diff --git a/doc/release-notes.md b/doc/release-notes.md
index 06c4dddc5..f93bb0067 100644
--- a/doc/release-notes.md
+++ b/doc/release-notes.md
@@ -1,38 +1,59 @@
 Bitcoin ABC version 0.19.7 is now available from:
 
   <https://download.bitcoinabc.org/0.19.7/>
 
 This release includes the following features and fixes:
  - `-includeconf=<file>` can be used to include additional configuration files.
   Only works inside the `bitcoin.conf` file, not inside included files or from
   command-line. Multiple files may be included. Can be disabled from command-
   line via `-noincludeconf`. Note that multi-argument commands like
   `-includeconf` will override preceding `-noincludeconf`, i.e.
     noincludeconf=1
     includeconf=relative.conf
   as bitcoin.conf will still include `relative.conf`.
  - The `createrawtransaction` RPC will now accept an array or dictionary (kept for compatibility) for the `outputs` parameter. This means the order of transaction outputs can be specified by the client.
  - The new RPC `testmempoolaccept` can be used to test acceptance of a transaction to the mempool without adding it.
  - An `initialblockdownload` boolean has been added to the `getblockchaininfo` RPC to indicate whether the node is currently in IBD or not.
  - The '-usehd' option has been removed. It is no longer possible to create a non HD wallet.
 
 External wallet files
 ---------------------
 
 The `-wallet=<path>` option now accepts full paths instead of requiring wallets
-to be located in the -walletdir directory. When wallets are located in
-different directories, wallet data will be stored independently, so data from
-every wallet is not mixed into the same <walletdir>/database/log.??????????
-files.
+to be located in the -walletdir directory.
+
+Newly created wallet format
+---------------------------
+
+If `-wallet=<path>` is specified with a path that does not exist, it will now
+create a wallet directory at the specified location (containing a wallet.dat
+data file, a db.log file, and database/log.?????????? files) instead of just
+creating a data file at the path and storing log files in the parent
+directory. This should make backing up wallets more straightforward than
+before because the specified wallet path can just be directly archived
+without having to look in the parent directory for transaction log files.
+
+For backwards compatibility, wallet paths that are names of existing data
+files in the `-walletdir` directory will continue to be accepted and
+interpreted the same as before.
+
+Low-level RPC changes
+---------------------
+
+ - When bitcoind is not started with any `-wallet=<path>` options, the name of
+   the default wallet returned by `getwalletinfo` and `listwallets` RPCs is now
+   the empty string `""` instead of `"wallet.dat"`. If bitcoind is started with
+   any `-wallet=<path>` options, there is no change in behavior, and the name of
+   any wallet is just its `<path>` string.
 
 Transaction index changes
 -------------------------
 
 The transaction index is now built separately from the main node procedure,
 meaning the `-txindex` flag can be toggled without a full reindex. If bitcoind
 is run with `-txindex` on a node that is already partially or fully synced
 without one, the transaction index will be built in the background and become
 available once caught up. When switching from running `-txindex` to running
 without the flag, the transaction index database will *not* be deleted
 automatically, meaning it could be turned back on at a later time without a full
 resync.
diff --git a/src/bitcoin-cli.cpp b/src/bitcoin-cli.cpp
index 587ca034f..594f84444 100644
--- a/src/bitcoin-cli.cpp
+++ b/src/bitcoin-cli.cpp
@@ -1,604 +1,604 @@
 // Copyright (c) 2009-2010 Satoshi Nakamoto
 // Copyright (c) 2009-2016 The Bitcoin Core developers
 // Distributed under the MIT software license, see the accompanying
 // file COPYING or http://www.opensource.org/licenses/mit-license.php.
 
 #if defined(HAVE_CONFIG_H)
 #include <config/bitcoin-config.h>
 #endif
 
 #include <chainparamsbase.h>
 #include <clientversion.h>
 #include <fs.h>
 #include <rpc/client.h>
 #include <rpc/protocol.h>
 #include <support/events.h>
 #include <util.h>
 #include <utilstrencodings.h>
 
 #include <boost/filesystem/operations.hpp>
 
 #include <event2/buffer.h>
 #include <event2/keyvalq_struct.h>
 
 #include <univalue.h>
 
 #include <cstdio>
 
 static const char DEFAULT_RPCCONNECT[] = "127.0.0.1";
 static const int DEFAULT_HTTP_CLIENT_TIMEOUT = 900;
 static const bool DEFAULT_NAMED = false;
 static const int CONTINUE_EXECUTION = -1;
 
 static void SetupCliArgs() {
     const auto defaultBaseParams =
         CreateBaseChainParams(CBaseChainParams::MAIN);
     const auto testnetBaseParams =
         CreateBaseChainParams(CBaseChainParams::TESTNET);
 
     gArgs.AddArg("-?", _("This help message"), false, OptionsCategory::OPTIONS);
     gArgs.AddArg("-conf=<file>",
                  strprintf(_("Specify configuration file (default: %s)"),
                            BITCOIN_CONF_FILENAME),
                  false, OptionsCategory::OPTIONS);
     gArgs.AddArg("-datadir=<dir>", _("Specify data directory"), false,
                  OptionsCategory::OPTIONS);
     gArgs.AddArg(
         "-getinfo",
         _("Get general information from the remote server. Note that unlike "
           "server-side RPC calls, the results of -getinfo is the result of "
           "multiple non-atomic requests. Some entries in the result may "
           "represent results from different states (e.g. wallet balance may be "
           "as of a different block from the chain state reported)"),
         false, OptionsCategory::OPTIONS);
     SetupChainParamsBaseOptions();
     gArgs.AddArg(
         "-named",
         strprintf(_("Pass named instead of positional arguments (default: %s)"),
                   DEFAULT_NAMED),
         false, OptionsCategory::OPTIONS);
     gArgs.AddArg(
         "-rpcconnect=<ip>",
         strprintf(_("Send commands to node running on <ip> (default: %s)"),
                   DEFAULT_RPCCONNECT),
         false, OptionsCategory::OPTIONS);
     gArgs.AddArg(
         "-rpcport=<port>",
         strprintf(
             _("Connect to JSON-RPC on <port> (default: %u or testnet: %u)"),
             defaultBaseParams->RPCPort(), testnetBaseParams->RPCPort()),
         false, OptionsCategory::OPTIONS);
     gArgs.AddArg("-rpcwait", _("Wait for RPC server to start"), false,
                  OptionsCategory::OPTIONS);
     gArgs.AddArg("-rpcuser=<user>", _("Username for JSON-RPC connections"),
                  false, OptionsCategory::OPTIONS);
     gArgs.AddArg("-rpcpassword=<pw>", _("Password for JSON-RPC connections"),
                  false, OptionsCategory::OPTIONS);
     gArgs.AddArg("-rpcclienttimeout=<n>",
                  strprintf(_("Timeout in seconds during HTTP requests, or 0 "
                              "for no timeout. (default: %d)"),
                            DEFAULT_HTTP_CLIENT_TIMEOUT),
                  false, OptionsCategory::OPTIONS);
 
     gArgs.AddArg(
         "-stdinrpcpass",
         strprintf(_("Read RPC password from standard input as a single line. "
                     "When combined with -stdin, the first line from standard "
                     "input is used for the RPC password.")),
         false, OptionsCategory::OPTIONS);
     gArgs.AddArg("-stdin",
                  _("Read extra arguments from standard input, one per line "
                    "until EOF/Ctrl-D (recommended for sensitive information "
                    "such as passphrases)"),
                  false, OptionsCategory::OPTIONS);
     gArgs.AddArg(
         "-rpcwallet=<walletname>",
         _("Send RPC for non-default wallet on RPC server (needs to exactly "
           "match corresponding -wallet option passed to bitcoind)"),
         false, OptionsCategory::OPTIONS);
 }
 
 //////////////////////////////////////////////////////////////////////////////
 //
 // Start
 //
 
 //
 // Exception thrown on connection error.  This error is used to determine when
 // to wait if -rpcwait is given.
 //
 class CConnectionFailed : public std::runtime_error {
 public:
     explicit inline CConnectionFailed(const std::string &msg)
         : std::runtime_error(msg) {}
 };
 
 //
 // This function returns either one of EXIT_ codes when it's expected to stop
 // the process or CONTINUE_EXECUTION when it's expected to continue further.
 //
 static int AppInitRPC(int argc, char *argv[]) {
     //
     // Parameters
     //
     SetupCliArgs();
     gArgs.ParseParameters(argc, argv);
     if (argc < 2 || HelpRequested(gArgs) || gArgs.IsArgSet("-version")) {
         std::string strUsage =
             PACKAGE_NAME " RPC client version " + FormatFullVersion() + "\n";
         if (!gArgs.IsArgSet("-version")) {
             strUsage += "\n"
                         "Usage:  bitcoin-cli [options] <command> [params]  "
                         "Send command to " PACKAGE_NAME "\n"
                         "or:     bitcoin-cli [options] -named <command> "
                         "[name=value]...  Send command to " PACKAGE_NAME
                         " (with named arguments)\n"
                         "or:     bitcoin-cli [options] help                "
                         "List commands\n"
                         "or:     bitcoin-cli [options] help <command>      Get "
                         "help for a command\n";
 
             strUsage += "\n" + gArgs.GetHelpMessage();
         }
 
         fprintf(stdout, "%s", strUsage.c_str());
         if (argc < 2) {
             fprintf(stderr, "Error: too few parameters\n");
             return EXIT_FAILURE;
         }
         return EXIT_SUCCESS;
     }
     if (!fs::is_directory(GetDataDir(false))) {
         fprintf(stderr,
                 "Error: Specified data directory \"%s\" does not exist.\n",
                 gArgs.GetArg("-datadir", "").c_str());
         return EXIT_FAILURE;
     }
     try {
         gArgs.ReadConfigFiles();
     } catch (const std::exception &e) {
         fprintf(stderr, "Error reading configuration file: %s\n", e.what());
         return EXIT_FAILURE;
     }
     // Check for -testnet or -regtest parameter (BaseParams() calls are only
     // valid after this clause)
     try {
         SelectBaseParams(gArgs.GetChainName());
     } catch (const std::exception &e) {
         fprintf(stderr, "Error: %s\n", e.what());
         return EXIT_FAILURE;
     }
     if (gArgs.GetBoolArg("-rpcssl", false)) {
         fprintf(stderr,
                 "Error: SSL mode for RPC (-rpcssl) is no longer supported.\n");
         return EXIT_FAILURE;
     }
     return CONTINUE_EXECUTION;
 }
 
 /** Reply structure for request_done to fill in */
 struct HTTPReply {
     HTTPReply() : status(0), error(-1) {}
 
     int status;
     int error;
     std::string body;
 };
 
 const char *http_errorstring(int code) {
     switch (code) {
 #if LIBEVENT_VERSION_NUMBER >= 0x02010300
         case EVREQ_HTTP_TIMEOUT:
             return "timeout reached";
         case EVREQ_HTTP_EOF:
             return "EOF reached";
         case EVREQ_HTTP_INVALID_HEADER:
             return "error while reading header, or invalid header";
         case EVREQ_HTTP_BUFFER_ERROR:
             return "error encountered while reading or writing";
         case EVREQ_HTTP_REQUEST_CANCEL:
             return "request was canceled";
         case EVREQ_HTTP_DATA_TOO_LONG:
             return "response body is larger than allowed";
 #endif
         default:
             return "unknown";
     }
 }
 
 static void http_request_done(struct evhttp_request *req, void *ctx) {
     HTTPReply *reply = static_cast<HTTPReply *>(ctx);
 
     if (req == nullptr) {
         /**
          * If req is nullptr, it means an error occurred while connecting: the
          * error code will have been passed to http_error_cb.
          */
         reply->status = 0;
         return;
     }
 
     reply->status = evhttp_request_get_response_code(req);
 
     struct evbuffer *buf = evhttp_request_get_input_buffer(req);
     if (buf) {
         size_t size = evbuffer_get_length(buf);
         const char *data = (const char *)evbuffer_pullup(buf, size);
         if (data) reply->body = std::string(data, size);
         evbuffer_drain(buf, size);
     }
 }
 
 #if LIBEVENT_VERSION_NUMBER >= 0x02010300
 static void http_error_cb(enum evhttp_request_error err, void *ctx) {
     HTTPReply *reply = static_cast<HTTPReply *>(ctx);
     reply->error = err;
 }
 #endif
 
 /**
  * Class that handles the conversion from a command-line to a JSON-RPC request,
  * as well as converting back to a JSON object that can be shown as result.
  */
 class BaseRequestHandler {
 public:
     virtual UniValue PrepareRequest(const std::string &method,
                                     const std::vector<std::string> &args) = 0;
     virtual UniValue ProcessReply(const UniValue &batch_in) = 0;
 };
 
 /** Process getinfo requests */
 class GetinfoRequestHandler : public BaseRequestHandler {
 public:
     const int ID_NETWORKINFO = 0;
     const int ID_BLOCKCHAININFO = 1;
     const int ID_WALLETINFO = 2;
 
     /** Create a simulated `getinfo` request. */
     UniValue PrepareRequest(const std::string &method,
                             const std::vector<std::string> &args) override {
         UniValue result(UniValue::VARR);
         result.push_back(
             JSONRPCRequestObj("getnetworkinfo", NullUniValue, ID_NETWORKINFO));
         result.push_back(JSONRPCRequestObj("getblockchaininfo", NullUniValue,
                                            ID_BLOCKCHAININFO));
         result.push_back(
             JSONRPCRequestObj("getwalletinfo", NullUniValue, ID_WALLETINFO));
         return result;
     }
 
     /** Collect values from the batch and form a simulated `getinfo` reply. */
     UniValue ProcessReply(const UniValue &batch_in) override {
         UniValue result(UniValue::VOBJ);
         std::vector<UniValue> batch = JSONRPCProcessBatchReply(batch_in, 3);
         // Errors in getnetworkinfo() and getblockchaininfo() are fatal, pass
         // them on getwalletinfo() is allowed to fail in case there is no
         // wallet.
         if (!batch[ID_NETWORKINFO]["error"].isNull()) {
             return batch[ID_NETWORKINFO];
         }
         if (!batch[ID_BLOCKCHAININFO]["error"].isNull()) {
             return batch[ID_BLOCKCHAININFO];
         }
         result.pushKV("version", batch[ID_NETWORKINFO]["result"]["version"]);
         result.pushKV("protocolversion",
                       batch[ID_NETWORKINFO]["result"]["protocolversion"]);
         if (!batch[ID_WALLETINFO].isNull()) {
             result.pushKV("walletversion",
                           batch[ID_WALLETINFO]["result"]["walletversion"]);
             result.pushKV("balance", batch[ID_WALLETINFO]["result"]["balance"]);
         }
         result.pushKV("blocks", batch[ID_BLOCKCHAININFO]["result"]["blocks"]);
         result.pushKV("timeoffset",
                       batch[ID_NETWORKINFO]["result"]["timeoffset"]);
         result.pushKV("connections",
                       batch[ID_NETWORKINFO]["result"]["connections"]);
         result.pushKV("proxy",
                       batch[ID_NETWORKINFO]["result"]["networks"][0]["proxy"]);
         result.pushKV("difficulty",
                       batch[ID_BLOCKCHAININFO]["result"]["difficulty"]);
         result.pushKV(
             "testnet",
             UniValue(batch[ID_BLOCKCHAININFO]["result"]["chain"].get_str() ==
                      "test"));
         if (!batch[ID_WALLETINFO].isNull()) {
             result.pushKV("walletversion",
                           batch[ID_WALLETINFO]["result"]["walletversion"]);
             result.pushKV("balance", batch[ID_WALLETINFO]["result"]["balance"]);
             result.pushKV("keypoololdest",
                           batch[ID_WALLETINFO]["result"]["keypoololdest"]);
             result.pushKV("keypoolsize",
                           batch[ID_WALLETINFO]["result"]["keypoolsize"]);
             if (!batch[ID_WALLETINFO]["result"]["unlocked_until"].isNull()) {
                 result.pushKV("unlocked_until",
                               batch[ID_WALLETINFO]["result"]["unlocked_until"]);
             }
             result.pushKV("paytxfee",
                           batch[ID_WALLETINFO]["result"]["paytxfee"]);
         }
         result.pushKV("relayfee", batch[ID_NETWORKINFO]["result"]["relayfee"]);
         result.pushKV("warnings", batch[ID_NETWORKINFO]["result"]["warnings"]);
         return JSONRPCReplyObj(result, NullUniValue, 1);
     }
 };
 
 /** Process default single requests */
 class DefaultRequestHandler : public BaseRequestHandler {
 public:
     UniValue PrepareRequest(const std::string &method,
                             const std::vector<std::string> &args) override {
         UniValue params;
         if (gArgs.GetBoolArg("-named", DEFAULT_NAMED)) {
             params = RPCConvertNamedValues(method, args);
         } else {
             params = RPCConvertValues(method, args);
         }
         return JSONRPCRequestObj(method, params, 1);
     }
 
     UniValue ProcessReply(const UniValue &reply) override {
         return reply.get_obj();
     }
 };
 
 static UniValue CallRPC(BaseRequestHandler *rh, const std::string &strMethod,
                         const std::vector<std::string> &args) {
     std::string host;
     // In preference order, we choose the following for the port:
     //     1. -rpcport
     //     2. port in -rpcconnect (ie following : in ipv4 or ]: in ipv6)
     //     3. default port for chain
     int port = BaseParams().RPCPort();
     SplitHostPort(gArgs.GetArg("-rpcconnect", DEFAULT_RPCCONNECT), port, host);
     port = gArgs.GetArg("-rpcport", port);
 
     // Obtain event base
     raii_event_base base = obtain_event_base();
 
     // Synchronously look up hostname
     raii_evhttp_connection evcon =
         obtain_evhttp_connection_base(base.get(), host, port);
     evhttp_connection_set_timeout(
         evcon.get(),
         gArgs.GetArg("-rpcclienttimeout", DEFAULT_HTTP_CLIENT_TIMEOUT));
 
     HTTPReply response;
     raii_evhttp_request req =
         obtain_evhttp_request(http_request_done, (void *)&response);
     if (req == nullptr) throw std::runtime_error("create http request failed");
 #if LIBEVENT_VERSION_NUMBER >= 0x02010300
     evhttp_request_set_error_cb(req.get(), http_error_cb);
 #endif
 
     // Get credentials
     std::string strRPCUserColonPass;
     if (gArgs.GetArg("-rpcpassword", "") == "") {
         // Try fall back to cookie-based authentication if no password is
         // provided
         if (!GetAuthCookie(&strRPCUserColonPass)) {
             throw std::runtime_error(strprintf(
                 _("Could not locate RPC credentials. No authentication cookie "
                   "could be found, and RPC password is not set.  See "
                   "-rpcpassword and -stdinrpcpass.  Configuration file: (%s)"),
                 GetConfigFile(gArgs.GetArg("-conf", BITCOIN_CONF_FILENAME))
                     .string()
                     .c_str()));
         }
     } else {
         strRPCUserColonPass = gArgs.GetArg("-rpcuser", "") + ":" +
                               gArgs.GetArg("-rpcpassword", "");
     }
 
     struct evkeyvalq *output_headers =
         evhttp_request_get_output_headers(req.get());
     assert(output_headers);
     evhttp_add_header(output_headers, "Host", host.c_str());
     evhttp_add_header(output_headers, "Connection", "close");
     evhttp_add_header(
         output_headers, "Authorization",
         (std::string("Basic ") + EncodeBase64(strRPCUserColonPass)).c_str());
 
     // Attach request data
     std::string strRequest = rh->PrepareRequest(strMethod, args).write() + "\n";
     struct evbuffer *output_buffer =
         evhttp_request_get_output_buffer(req.get());
     assert(output_buffer);
     evbuffer_add(output_buffer, strRequest.data(), strRequest.size());
 
     // check if we should use a special wallet endpoint
     std::string endpoint = "/";
-    std::string walletName = gArgs.GetArg("-rpcwallet", "");
-    if (!walletName.empty()) {
+    if (!gArgs.GetArgs("-rpcwallet").empty()) {
+        std::string walletName = gArgs.GetArg("-rpcwallet", "");
         char *encodedURI =
             evhttp_uriencode(walletName.c_str(), walletName.size(), false);
         if (encodedURI) {
             endpoint = "/wallet/" + std::string(encodedURI);
             free(encodedURI);
         } else {
             throw CConnectionFailed("uri-encode failed");
         }
     }
     int r = evhttp_make_request(evcon.get(), req.get(), EVHTTP_REQ_POST,
                                 endpoint.c_str());
     // ownership moved to evcon in above call
     req.release();
     if (r != 0) {
         throw CConnectionFailed("send http request failed");
     }
 
     event_base_dispatch(base.get());
 
     if (response.status == 0) {
         throw CConnectionFailed(strprintf(
             "couldn't connect to server: %s (code %d)\n(make sure server is "
             "running and you are connecting to the correct RPC port)",
             http_errorstring(response.error), response.error));
     } else if (response.status == HTTP_UNAUTHORIZED) {
         throw std::runtime_error(
             "incorrect rpcuser or rpcpassword (authorization failed)");
     } else if (response.status >= 400 && response.status != HTTP_BAD_REQUEST &&
                response.status != HTTP_NOT_FOUND &&
                response.status != HTTP_INTERNAL_SERVER_ERROR) {
         throw std::runtime_error(
             strprintf("server returned HTTP error %d", response.status));
     } else if (response.body.empty()) {
         throw std::runtime_error("no response from server");
     }
 
     // Parse reply
     UniValue valReply(UniValue::VSTR);
     if (!valReply.read(response.body)) {
         throw std::runtime_error("couldn't parse reply from server");
     }
     const UniValue reply = rh->ProcessReply(valReply);
     if (reply.empty()) {
         throw std::runtime_error(
             "expected reply to have result, error and id properties");
     }
 
     return reply;
 }
 
 int CommandLineRPC(int argc, char *argv[]) {
     std::string strPrint;
     int nRet = 0;
     try {
         // Skip switches
         while (argc > 1 && IsSwitchChar(argv[1][0])) {
             argc--;
             argv++;
         }
         std::string rpcPass;
         if (gArgs.GetBoolArg("-stdinrpcpass", false)) {
             if (!std::getline(std::cin, rpcPass))
                 throw std::runtime_error("-stdinrpcpass specified but failed "
                                          "to read from standard input");
             gArgs.ForceSetArg("-rpcpassword", rpcPass);
         }
         std::vector<std::string> args =
             std::vector<std::string>(&argv[1], &argv[argc]);
         if (gArgs.GetBoolArg("-stdin", false)) {
             // Read one arg per line from stdin and append
             std::string line;
             while (std::getline(std::cin, line)) {
                 args.push_back(line);
             }
         }
         std::unique_ptr<BaseRequestHandler> rh;
         std::string method;
         if (gArgs.GetBoolArg("-getinfo", false)) {
             rh.reset(new GetinfoRequestHandler());
             method = "";
         } else {
             rh.reset(new DefaultRequestHandler());
             if (args.size() < 1) {
                 throw std::runtime_error(
                     "too few parameters (need at least command)");
             }
             method = args[0];
             // Remove trailing method name from arguments vector
             args.erase(args.begin());
         }
 
         // Execute and handle connection failures with -rpcwait
         const bool fWait = gArgs.GetBoolArg("-rpcwait", false);
         do {
             try {
                 const UniValue reply = CallRPC(rh.get(), method, args);
 
                 // Parse reply
                 const UniValue &result = find_value(reply, "result");
                 const UniValue &error = find_value(reply, "error");
 
                 if (!error.isNull()) {
                     // Error
                     int code = error["code"].get_int();
                     if (fWait && code == RPC_IN_WARMUP)
                         throw CConnectionFailed("server in warmup");
                     strPrint = "error: " + error.write();
                     nRet = abs(code);
                     if (error.isObject()) {
                         UniValue errCode = find_value(error, "code");
                         UniValue errMsg = find_value(error, "message");
                         strPrint =
                             errCode.isNull()
                                 ? ""
                                 : "error code: " + errCode.getValStr() + "\n";
 
                         if (errMsg.isStr()) {
                             strPrint += "error message:\n" + errMsg.get_str();
                         }
 
                         if (errCode.isNum() &&
                             errCode.get_int() == RPC_WALLET_NOT_SPECIFIED) {
                             strPrint += "\nTry adding "
                                         "\"-rpcwallet=<filename>\" option to "
                                         "bitcoin-cli command line.";
                         }
                     }
                 } else {
                     // Result
                     if (result.isNull()) {
                         strPrint = "";
                     } else if (result.isStr()) {
                         strPrint = result.get_str();
                     } else {
                         strPrint = result.write(2);
                     }
                 }
                 // Connection succeeded, no need to retry.
                 break;
             } catch (const CConnectionFailed &) {
                 if (fWait) {
                     MilliSleep(1000);
                 } else {
                     throw;
                 }
             }
         } while (fWait);
     } catch (const boost::thread_interrupted &) {
         throw;
     } catch (const std::exception &e) {
         strPrint = std::string("error: ") + e.what();
         nRet = EXIT_FAILURE;
     } catch (...) {
         PrintExceptionContinue(nullptr, "CommandLineRPC()");
         throw;
     }
 
     if (strPrint != "") {
         fprintf((nRet == 0 ? stdout : stderr), "%s\n", strPrint.c_str());
     }
     return nRet;
 }
 
 int main(int argc, char *argv[]) {
     SetupEnvironment();
     if (!SetupNetworking()) {
         fprintf(stderr, "Error: Initializing networking failed\n");
         return EXIT_FAILURE;
     }
 
     try {
         int ret = AppInitRPC(argc, argv);
         if (ret != CONTINUE_EXECUTION) {
             return ret;
         }
     } catch (const std::exception &e) {
         PrintExceptionContinue(&e, "AppInitRPC()");
         return EXIT_FAILURE;
     } catch (...) {
         PrintExceptionContinue(nullptr, "AppInitRPC()");
         return EXIT_FAILURE;
     }
 
     int ret = EXIT_FAILURE;
     try {
         ret = CommandLineRPC(argc, argv);
     } catch (const std::exception &e) {
         PrintExceptionContinue(&e, "CommandLineRPC()");
     } catch (...) {
         PrintExceptionContinue(nullptr, "CommandLineRPC()");
     }
     return ret;
 }
diff --git a/src/wallet/db.cpp b/src/wallet/db.cpp
index 565066d6a..b5257cc4c 100644
--- a/src/wallet/db.cpp
+++ b/src/wallet/db.cpp
@@ -1,847 +1,858 @@
 // Copyright (c) 2009-2010 Satoshi Nakamoto
 // Copyright (c) 2009-2016 The Bitcoin Core developers
 // Distributed under the MIT software license, see the accompanying
 // file COPYING or http://www.opensource.org/licenses/mit-license.php.
 
 #include <wallet/db.h>
 
 #include <addrman.h>
 #include <fs.h>
 #include <hash.h>
 #include <protocol.h>
 #include <util.h>
 #include <utilstrencodings.h>
 #include <wallet/walletutil.h>
 
 #include <boost/thread.hpp> // boost::this_thread::interruption_point() (mingw)
 #include <boost/version.hpp>
 
 #include <cstdint>
 #ifndef WIN32
 #include <sys/stat.h>
 #endif
 
 namespace {
 //! Make sure database has a unique fileid within the environment. If it
 //! doesn't, throw an error. BDB caches do not work properly when more than one
 //! open database has the same fileid (values written to one database may show
 //! up in reads to other databases).
 //!
 //! BerkeleyDB generates unique fileids by default
 //! (https://docs.oracle.com/cd/E17275_01/html/programmer_reference/program_copy.html),
 //! so bitcoin should never create different databases with the same fileid, but
 //! this error can be triggered if users manually copy database files.
 void CheckUniqueFileid(const CDBEnv &env, const std::string &filename, Db &db) {
     if (env.IsMock()) {
         return;
     }
 
     u_int8_t fileid[DB_FILE_ID_LEN];
     int ret = db.get_mpf()->get_fileid(fileid);
     if (ret != 0) {
         throw std::runtime_error(
             strprintf("CDB: Can't open database %s (get_fileid failed with %d)",
                       filename, ret));
     }
 
     for (const auto &item : env.mapDb) {
         u_int8_t item_fileid[DB_FILE_ID_LEN];
         if (item.second &&
             item.second->get_mpf()->get_fileid(item_fileid) == 0 &&
             memcmp(fileid, item_fileid, sizeof(fileid)) == 0) {
             const char *item_filename = nullptr;
             item.second->get_dbname(&item_filename, nullptr);
             throw std::runtime_error(strprintf(
                 "CDB: Can't open database %s (duplicates fileid %s from %s)",
                 filename,
                 HexStr(std::begin(item_fileid), std::end(item_fileid)),
                 item_filename ? item_filename : "(unknown database)"));
         }
     }
 }
 
 CCriticalSection cs_db;
 //!< Map from directory name to open db environment.
 std::map<std::string, CDBEnv> g_dbenvs;
 } // namespace
 
 CDBEnv *GetWalletEnv(const fs::path &wallet_path,
                      std::string &database_filename) {
-    fs::path env_directory = wallet_path.parent_path();
-    database_filename = wallet_path.filename().string();
+    fs::path env_directory;
+    if (fs::is_regular_file(wallet_path)) {
+        // Special case for backwards compatibility: if wallet path points to an
+        // existing file, treat it as the path to a BDB data file in a parent
+        // directory that also contains BDB log files.
+        env_directory = wallet_path.parent_path();
+        database_filename = wallet_path.filename().string();
+    } else {
+        // Normal case: Interpret wallet path as a directory path containing
+        // data and log files.
+        env_directory = wallet_path;
+        database_filename = "wallet.dat";
+    }
     LOCK(cs_db);
     // Note: An ununsed temporary CDBEnv object may be created inside the
     // emplace function if the key already exists. This is a little inefficient,
     // but not a big concern since the map will be changed in the future to hold
     // pointers instead of objects, anyway.
     return &g_dbenvs
                 .emplace(std::piecewise_construct,
                          std::forward_as_tuple(env_directory.string()),
                          std::forward_as_tuple(env_directory))
                 .first->second;
 }
 
 //
 // CDB
 //
 
 void CDBEnv::Close() {
     if (!fDbEnvInit) {
         return;
     }
 
     fDbEnvInit = false;
 
     for (auto &db : mapDb) {
         auto count = mapFileUseCount.find(db.first);
         assert(count == mapFileUseCount.end() || count->second == 0);
         if (db.second) {
             db.second->close(0);
             delete db.second;
             db.second = nullptr;
         }
     }
 
     int ret = dbenv->close(0);
     if (ret != 0) {
         LogPrintf("CDBEnv::EnvShutdown: Error %d shutting down database "
                   "environment: %s\n",
                   ret, DbEnv::strerror(ret));
     }
 
     if (!fMockDb) {
         DbEnv(uint32_t(0)).remove(strPath.c_str(), 0);
     }
 }
 
 void CDBEnv::Reset() {
     dbenv.reset(new DbEnv(DB_CXX_NO_EXCEPTIONS));
     fDbEnvInit = false;
     fMockDb = false;
 }
 
 CDBEnv::CDBEnv(const fs::path &dir_path) : strPath(dir_path.string()) {
     Reset();
 }
 
 CDBEnv::~CDBEnv() {
     Close();
 }
 
 bool CDBEnv::Open(bool retry) {
     if (fDbEnvInit) {
         return true;
     }
 
     boost::this_thread::interruption_point();
 
     fs::path pathIn = strPath;
     TryCreateDirectories(pathIn);
     if (!LockDirectory(pathIn, ".walletlock")) {
         LogPrintf("Cannot obtain a lock on wallet directory %s. Another "
                   "instance of bitcoin may be using it.\n",
                   strPath);
         return false;
     }
 
     fs::path pathLogDir = pathIn / "database";
     TryCreateDirectories(pathLogDir);
     fs::path pathErrorFile = pathIn / "db.log";
     LogPrintf("CDBEnv::Open: LogDir=%s ErrorFile=%s\n", pathLogDir.string(),
               pathErrorFile.string());
 
     unsigned int nEnvFlags = 0;
     if (gArgs.GetBoolArg("-privdb", DEFAULT_WALLET_PRIVDB)) {
         nEnvFlags |= DB_PRIVATE;
     }
 
     dbenv->set_lg_dir(pathLogDir.string().c_str());
     // 1 MiB should be enough for just the wallet
     dbenv->set_cachesize(0, 0x100000, 1);
     dbenv->set_lg_bsize(0x10000);
     dbenv->set_lg_max(1048576);
     dbenv->set_lk_max_locks(40000);
     dbenv->set_lk_max_objects(40000);
     /// debug
     dbenv->set_errfile(fsbridge::fopen(pathErrorFile, "a"));
     dbenv->set_flags(DB_AUTO_COMMIT, 1);
     dbenv->set_flags(DB_TXN_WRITE_NOSYNC, 1);
     dbenv->log_set_config(DB_LOG_AUTO_REMOVE, 1);
     int ret =
         dbenv->open(strPath.c_str(),
                     DB_CREATE | DB_INIT_LOCK | DB_INIT_LOG | DB_INIT_MPOOL |
                         DB_INIT_TXN | DB_THREAD | DB_RECOVER | nEnvFlags,
                     S_IRUSR | S_IWUSR);
     if (ret != 0) {
         dbenv->close(0);
         LogPrintf("CDBEnv::Open: Error %d opening database environment: %s\n",
                   ret, DbEnv::strerror(ret));
         if (retry) {
             // try moving the database env out of the way
             fs::path pathDatabaseBak =
                 pathIn / strprintf("database.%d.bak", GetTime());
             try {
                 fs::rename(pathLogDir, pathDatabaseBak);
                 LogPrintf("Moved old %s to %s. Retrying.\n",
                           pathLogDir.string(), pathDatabaseBak.string());
             } catch (const fs::filesystem_error &) {
                 // failure is ok (well, not really, but it's not worse than what
                 // we started with)
             }
             // try opening it again one more time
             if (!Open(false /* retry */)) {
                 // if it still fails, it probably means we can't even create the
                 // database env
                 return false;
             }
         } else {
             return false;
         }
     }
 
     fDbEnvInit = true;
     fMockDb = false;
     return true;
 }
 
 void CDBEnv::MakeMock() {
     if (fDbEnvInit) {
         throw std::runtime_error("CDBEnv::MakeMock: Already initialized");
     }
 
     boost::this_thread::interruption_point();
 
     LogPrint(BCLog::DB, "CDBEnv::MakeMock\n");
 
     dbenv->set_cachesize(1, 0, 1);
     dbenv->set_lg_bsize(10485760 * 4);
     dbenv->set_lg_max(10485760);
     dbenv->set_lk_max_locks(10000);
     dbenv->set_lk_max_objects(10000);
     dbenv->set_flags(DB_AUTO_COMMIT, 1);
     dbenv->log_set_config(DB_LOG_IN_MEMORY, 1);
     int ret =
         dbenv->open(nullptr,
                     DB_CREATE | DB_INIT_LOCK | DB_INIT_LOG | DB_INIT_MPOOL |
                         DB_INIT_TXN | DB_THREAD | DB_PRIVATE,
                     S_IRUSR | S_IWUSR);
     if (ret > 0) {
         throw std::runtime_error(strprintf(
             "CDBEnv::MakeMock: Error %d opening database environment.", ret));
     }
 
     fDbEnvInit = true;
     fMockDb = true;
 }
 
 CDBEnv::VerifyResult CDBEnv::Verify(const std::string &strFile,
                                     recoverFunc_type recoverFunc,
                                     std::string &out_backup_filename) {
     LOCK(cs_db);
     assert(mapFileUseCount.count(strFile) == 0);
 
     Db db(dbenv.get(), 0);
     int result = db.verify(strFile.c_str(), nullptr, nullptr, 0);
     if (result == 0) {
         return VerifyResult::VERIFY_OK;
     } else if (recoverFunc == nullptr) {
         return VerifyResult::RECOVER_FAIL;
     }
 
     // Try to recover:
     bool fRecovered =
         (*recoverFunc)(fs::path(strPath) / strFile, out_backup_filename);
     return (fRecovered ? VerifyResult::RECOVER_OK : VerifyResult::RECOVER_FAIL);
 }
 
 bool CDB::Recover(const fs::path &file_path, void *callbackDataIn,
                   bool (*recoverKVcallback)(void *callbackData,
                                             CDataStream ssKey,
                                             CDataStream ssValue),
                   std::string &newFilename) {
     std::string filename;
     CDBEnv *env = GetWalletEnv(file_path, filename);
 
     // Recovery procedure:
     // Move wallet file to walletfilename.timestamp.bak
     // Call Salvage with fAggressive=true to get as much data as possible.
     // Rewrite salvaged data to fresh wallet file.
     // Set -rescan so any missing transactions will be found.
     int64_t now = GetTime();
     newFilename = strprintf("%s.%d.bak", filename, now);
 
     int result = env->dbenv->dbrename(nullptr, filename.c_str(), nullptr,
                                       newFilename.c_str(), DB_AUTO_COMMIT);
     if (result == 0) {
         LogPrintf("Renamed %s to %s\n", filename, newFilename);
     } else {
         LogPrintf("Failed to rename %s to %s\n", filename, newFilename);
         return false;
     }
 
     std::vector<CDBEnv::KeyValPair> salvagedData;
     bool fSuccess = env->Salvage(newFilename, true, salvagedData);
     if (salvagedData.empty()) {
         LogPrintf("Salvage(aggressive) found no records in %s.\n", newFilename);
         return false;
     }
     LogPrintf("Salvage(aggressive) found %u records\n", salvagedData.size());
 
     std::unique_ptr<Db> pdbCopy = std::make_unique<Db>(env->dbenv.get(), 0);
     int ret = pdbCopy->open(nullptr,          // Txn pointer
                             filename.c_str(), // Filename
                             "main",           // Logical db name
                             DB_BTREE,         // Database type
                             DB_CREATE,        // Flags
                             0);
     if (ret > 0) {
         LogPrintf("Cannot create database file %s\n", filename);
         pdbCopy->close(0);
         return false;
     }
 
     DbTxn *ptxn = env->TxnBegin();
     for (CDBEnv::KeyValPair &row : salvagedData) {
         if (recoverKVcallback) {
             CDataStream ssKey(row.first, SER_DISK, CLIENT_VERSION);
             CDataStream ssValue(row.second, SER_DISK, CLIENT_VERSION);
             std::string strType, strErr;
             if (!(*recoverKVcallback)(callbackDataIn, ssKey, ssValue)) {
                 continue;
             }
         }
         Dbt datKey(&row.first[0], row.first.size());
         Dbt datValue(&row.second[0], row.second.size());
         int ret2 = pdbCopy->put(ptxn, &datKey, &datValue, DB_NOOVERWRITE);
         if (ret2 > 0) {
             fSuccess = false;
         }
     }
     ptxn->commit(0);
     pdbCopy->close(0);
 
     return fSuccess;
 }
 
 bool CDB::VerifyEnvironment(const fs::path &file_path, std::string &errorStr) {
     std::string walletFile;
     CDBEnv *env = GetWalletEnv(file_path, walletFile);
     fs::path walletDir = env->Directory();
 
     LogPrintf("Using BerkeleyDB version %s\n", DbEnv::version(0, 0, 0));
     LogPrintf("Using wallet %s\n", walletFile);
 
     // Wallet file must be a plain filename without a directory
     if (walletFile != fs::basename(walletFile) + fs::extension(walletFile)) {
         errorStr = strprintf(_("Wallet %s resides outside wallet directory %s"),
                              walletFile, walletDir.string());
         return false;
     }
 
     if (!env->Open(true /* retry */)) {
         errorStr = strprintf(
             _("Error initializing wallet database environment %s!"), walletDir);
         return false;
     }
 
     return true;
 }
 
 bool CDB::VerifyDatabaseFile(const fs::path &file_path, std::string &warningStr,
                              std::string &errorStr,
                              CDBEnv::recoverFunc_type recoverFunc) {
     std::string walletFile;
     CDBEnv *env = GetWalletEnv(file_path, walletFile);
     fs::path walletDir = env->Directory();
 
     if (fs::exists(walletDir / walletFile)) {
         std::string backup_filename;
         CDBEnv::VerifyResult r =
             env->Verify(walletFile, recoverFunc, backup_filename);
         if (r == CDBEnv::VerifyResult::RECOVER_OK) {
             warningStr = strprintf(
                 _("Warning: Wallet file corrupt, data salvaged!"
                   " Original %s saved as %s in %s; if"
                   " your balance or transactions are incorrect you should"
                   " restore from a backup."),
                 walletFile, backup_filename, walletDir);
         }
         if (r == CDBEnv::VerifyResult::RECOVER_FAIL) {
             errorStr = strprintf(_("%s corrupt, salvage failed"), walletFile);
             return false;
         }
     }
     // also return true if files does not exists
     return true;
 }
 
 /* End of headers, beginning of key/value data */
 static const char *HEADER_END = "HEADER=END";
 /* End of key/value data */
 static const char *DATA_END = "DATA=END";
 
 bool CDBEnv::Salvage(const std::string &strFile, bool fAggressive,
                      std::vector<CDBEnv::KeyValPair> &vResult) {
     LOCK(cs_db);
     assert(mapFileUseCount.count(strFile) == 0);
 
     u_int32_t flags = DB_SALVAGE;
     if (fAggressive) {
         flags |= DB_AGGRESSIVE;
     }
 
     std::stringstream strDump;
 
     Db db(dbenv.get(), 0);
     int result = db.verify(strFile.c_str(), nullptr, &strDump, flags);
     if (result == DB_VERIFY_BAD) {
         LogPrintf("CDBEnv::Salvage: Database salvage found errors, all data "
                   "may not be recoverable.\n");
         if (!fAggressive) {
             LogPrintf("CDBEnv::Salvage: Rerun with aggressive mode to ignore "
                       "errors and continue.\n");
             return false;
         }
     }
     if (result != 0 && result != DB_VERIFY_BAD) {
         LogPrintf("CDBEnv::Salvage: Database salvage failed with result %d.\n",
                   result);
         return false;
     }
 
     // Format of bdb dump is ascii lines:
     // header lines...
     // HEADER=END
     //  hexadecimal key
     //  hexadecimal value
     //  ... repeated
     // DATA=END
 
     std::string strLine;
     while (!strDump.eof() && strLine != HEADER_END) {
         // Skip past header
         getline(strDump, strLine);
     }
 
     std::string keyHex, valueHex;
     while (!strDump.eof() && keyHex != DATA_END) {
         getline(strDump, keyHex);
         if (keyHex != DATA_END) {
             if (strDump.eof()) {
                 break;
             }
             getline(strDump, valueHex);
             if (valueHex == DATA_END) {
                 LogPrintf("CDBEnv::Salvage: WARNING: Number of keys in data "
                           "does not match number of values.\n");
                 break;
             }
             vResult.push_back(make_pair(ParseHex(keyHex), ParseHex(valueHex)));
         }
     }
 
     if (keyHex != DATA_END) {
         LogPrintf("CDBEnv::Salvage: WARNING: Unexpected end of file while "
                   "reading salvage output.\n");
         return false;
     }
 
     return (result == 0);
 }
 
 void CDBEnv::CheckpointLSN(const std::string &strFile) {
     dbenv->txn_checkpoint(0, 0, 0);
     if (fMockDb) {
         return;
     }
     dbenv->lsn_reset(strFile.c_str(), 0);
 }
 
 CDB::CDB(CWalletDBWrapper &dbw, const char *pszMode, bool fFlushOnCloseIn)
     : pdb(nullptr), activeTxn(nullptr) {
     int ret;
     fReadOnly = (!strchr(pszMode, '+') && !strchr(pszMode, 'w'));
     fFlushOnClose = fFlushOnCloseIn;
     env = dbw.env;
     if (dbw.IsDummy()) {
         return;
     }
 
     const std::string &strFilename = dbw.strFile;
 
     bool fCreate = strchr(pszMode, 'c') != nullptr;
     unsigned int nFlags = DB_THREAD;
     if (fCreate) {
         nFlags |= DB_CREATE;
     }
 
     {
         LOCK(cs_db);
         if (!env->Open(false /* retry */)) {
             throw std::runtime_error(
                 "CDB: Failed to open database environment.");
         }
 
         pdb = env->mapDb[strFilename];
         if (pdb == nullptr) {
             std::unique_ptr<Db> pdb_temp =
                 std::make_unique<Db>(env->dbenv.get(), 0);
 
             bool fMockDb = env->IsMock();
             if (fMockDb) {
                 DbMpoolFile *mpf = pdb_temp->get_mpf();
                 ret = mpf->set_flags(DB_MPOOL_NOFILE, 1);
                 if (ret != 0) {
                     throw std::runtime_error(
                         strprintf("CDB: Failed to configure for no temp file "
                                   "backing for database %s",
                                   strFilename));
                 }
             }
 
             ret = pdb_temp->open(
                 nullptr,                                 // Txn pointer
                 fMockDb ? nullptr : strFilename.c_str(), // Filename
                 fMockDb ? strFilename.c_str() : "main",  // Logical db name
                 DB_BTREE,                                // Database type
                 nFlags,                                  // Flags
                 0);
 
             if (ret != 0) {
                 throw std::runtime_error(strprintf(
                     "CDB: Error %d, can't open database %s", ret, strFilename));
             }
 
             // Call CheckUniqueFileid on the containing BDB environment to
             // avoid BDB data consistency bugs that happen when different data
             // files in the same environment have the same fileid.
             //
             // Also call CheckUniqueFileid on all the other g_dbenvs to prevent
             // bitcoin from opening the same data file through another
             // environment when the file is referenced through equivalent but
             // not obviously identical symlinked or hard linked or bind mounted
             // paths. In the future a more relaxed check for equal inode and
             // device ids could be done instead, which would allow opening
             // different backup copies of a wallet at the same time. Maybe even
             // more ideally, an exclusive lock for accessing the database could
             // be implemented, so no equality checks are needed at all. (Newer
             // versions of BDB have an set_lk_exclusive method for this
             // purpose, but the older version we use does not.)
             for (auto &dbenv : g_dbenvs) {
                 CheckUniqueFileid(dbenv.second, strFilename, *pdb_temp);
             }
 
             pdb = pdb_temp.release();
             env->mapDb[strFilename] = pdb;
 
             if (fCreate && !Exists(std::string("version"))) {
                 bool fTmp = fReadOnly;
                 fReadOnly = false;
                 WriteVersion(CLIENT_VERSION);
                 fReadOnly = fTmp;
             }
         }
         ++env->mapFileUseCount[strFilename];
         strFile = strFilename;
     }
 }
 
 void CDB::Flush() {
     if (activeTxn) {
         return;
     }
 
     // Flush database activity from memory pool to disk log
     unsigned int nMinutes = 0;
     if (fReadOnly) {
         nMinutes = 1;
     }
 
     env->dbenv->txn_checkpoint(
         nMinutes ? gArgs.GetArg("-dblogsize", DEFAULT_WALLET_DBLOGSIZE) * 1024
                  : 0,
         nMinutes, 0);
 }
 
 void CWalletDBWrapper::IncrementUpdateCounter() {
     ++nUpdateCounter;
 }
 
 void CDB::Close() {
     if (!pdb) {
         return;
     }
     if (activeTxn) {
         activeTxn->abort();
     }
     activeTxn = nullptr;
     pdb = nullptr;
 
     if (fFlushOnClose) {
         Flush();
     }
 
     LOCK(cs_db);
     --env->mapFileUseCount[strFile];
 }
 
 void CDBEnv::CloseDb(const std::string &strFile) {
     LOCK(cs_db);
     if (mapDb[strFile] != nullptr) {
         // Close the database handle
         Db *pdb = mapDb[strFile];
         pdb->close(0);
         delete pdb;
         mapDb[strFile] = nullptr;
     }
 }
 
 bool CDB::Rewrite(CWalletDBWrapper &dbw, const char *pszSkip) {
     if (dbw.IsDummy()) {
         return true;
     }
     CDBEnv *env = dbw.env;
     const std::string &strFile = dbw.strFile;
     while (true) {
         {
             LOCK(cs_db);
             if (!env->mapFileUseCount.count(strFile) ||
                 env->mapFileUseCount[strFile] == 0) {
                 // Flush log data to the dat file
                 env->CloseDb(strFile);
                 env->CheckpointLSN(strFile);
                 env->mapFileUseCount.erase(strFile);
 
                 bool fSuccess = true;
                 LogPrintf("CDB::Rewrite: Rewriting %s...\n", strFile);
                 std::string strFileRes = strFile + ".rewrite";
                 {
                     // surround usage of db with extra {}
                     CDB db(dbw, "r");
                     std::unique_ptr<Db> pdbCopy =
                         std::make_unique<Db>(env->dbenv.get(), 0);
 
                     int ret = pdbCopy->open(nullptr,            // Txn pointer
                                             strFileRes.c_str(), // Filename
                                             "main",    // Logical db name
                                             DB_BTREE,  // Database type
                                             DB_CREATE, // Flags
                                             0);
                     if (ret > 0) {
                         LogPrintf(
                             "CDB::Rewrite: Can't create database file %s\n",
                             strFileRes);
                         fSuccess = false;
                     }
 
                     Dbc *pcursor = db.GetCursor();
                     if (pcursor)
                         while (fSuccess) {
                             CDataStream ssKey(SER_DISK, CLIENT_VERSION);
                             CDataStream ssValue(SER_DISK, CLIENT_VERSION);
                             int ret1 = db.ReadAtCursor(pcursor, ssKey, ssValue);
                             if (ret1 == DB_NOTFOUND) {
                                 pcursor->close();
                                 break;
                             }
                             if (ret1 != 0) {
                                 pcursor->close();
                                 fSuccess = false;
                                 break;
                             }
                             if (pszSkip &&
                                 strncmp(ssKey.data(), pszSkip,
                                         std::min(ssKey.size(),
                                                  strlen(pszSkip))) == 0) {
                                 continue;
                             }
                             if (strncmp(ssKey.data(), "\x07version", 8) == 0) {
                                 // Update version:
                                 ssValue.clear();
                                 ssValue << CLIENT_VERSION;
                             }
                             Dbt datKey(ssKey.data(), ssKey.size());
                             Dbt datValue(ssValue.data(), ssValue.size());
                             int ret2 = pdbCopy->put(nullptr, &datKey, &datValue,
                                                     DB_NOOVERWRITE);
                             if (ret2 > 0) {
                                 fSuccess = false;
                             }
                         }
                     if (fSuccess) {
                         db.Close();
                         env->CloseDb(strFile);
                         if (pdbCopy->close(0)) {
                             fSuccess = false;
                         }
                     } else {
                         pdbCopy->close(0);
                     }
                 }
                 if (fSuccess) {
                     Db dbA(env->dbenv.get(), 0);
                     if (dbA.remove(strFile.c_str(), nullptr, 0)) {
                         fSuccess = false;
                     }
                     Db dbB(env->dbenv.get(), 0);
                     if (dbB.rename(strFileRes.c_str(), nullptr, strFile.c_str(),
                                    0)) {
                         fSuccess = false;
                     }
                 }
                 if (!fSuccess) {
                     LogPrintf(
                         "CDB::Rewrite: Failed to rewrite database file %s\n",
                         strFileRes);
                 }
                 return fSuccess;
             }
         }
         MilliSleep(100);
     }
     return false;
 }
 
 void CDBEnv::Flush(bool fShutdown) {
     int64_t nStart = GetTimeMillis();
     // Flush log data to the actual data file on all files that are not in use
     LogPrint(BCLog::DB, "CDBEnv::Flush: Flush(%s)%s\n",
              fShutdown ? "true" : "false",
              fDbEnvInit ? "" : " database not started");
     if (!fDbEnvInit) {
         return;
     }
     {
         LOCK(cs_db);
         std::map<std::string, int>::iterator mi = mapFileUseCount.begin();
         while (mi != mapFileUseCount.end()) {
             std::string strFile = (*mi).first;
             int nRefCount = (*mi).second;
             LogPrint(BCLog::DB,
                      "CDBEnv::Flush: Flushing %s (refcount = %d)...\n", strFile,
                      nRefCount);
             if (nRefCount == 0) {
                 // Move log data to the dat file
                 CloseDb(strFile);
                 LogPrint(BCLog::DB, "CDBEnv::Flush: %s checkpoint\n", strFile);
                 dbenv->txn_checkpoint(0, 0, 0);
                 LogPrint(BCLog::DB, "CDBEnv::Flush: %s detach\n", strFile);
                 if (!fMockDb) {
                     dbenv->lsn_reset(strFile.c_str(), 0);
                 }
                 LogPrint(BCLog::DB, "CDBEnv::Flush: %s closed\n", strFile);
                 mapFileUseCount.erase(mi++);
             } else {
                 mi++;
             }
         }
         LogPrint(BCLog::DB, "CDBEnv::Flush: Flush(%s)%s took %15dms\n",
                  fShutdown ? "true" : "false",
                  fDbEnvInit ? "" : " database not started",
                  GetTimeMillis() - nStart);
         if (fShutdown) {
             char **listp;
             if (mapFileUseCount.empty()) {
                 dbenv->log_archive(&listp, DB_ARCH_REMOVE);
                 Close();
                 if (!fMockDb) {
                     fs::remove_all(fs::path(strPath) / "database");
                 }
             }
         }
     }
 }
 
 bool CDB::PeriodicFlush(CWalletDBWrapper &dbw) {
     if (dbw.IsDummy()) {
         return true;
     }
     bool ret = false;
     CDBEnv *env = dbw.env;
     const std::string &strFile = dbw.strFile;
     TRY_LOCK(cs_db, lockDb);
     if (lockDb) {
         // Don't do this if any databases are in use
         int nRefCount = 0;
         std::map<std::string, int>::iterator mit = env->mapFileUseCount.begin();
         while (mit != env->mapFileUseCount.end()) {
             nRefCount += (*mit).second;
             mit++;
         }
 
         if (nRefCount == 0) {
             boost::this_thread::interruption_point();
             std::map<std::string, int>::iterator mi =
                 env->mapFileUseCount.find(strFile);
             if (mi != env->mapFileUseCount.end()) {
                 LogPrint(BCLog::DB, "Flushing %s\n", strFile);
                 int64_t nStart = GetTimeMillis();
 
                 // Flush wallet file so it's self contained
                 env->CloseDb(strFile);
                 env->CheckpointLSN(strFile);
 
                 env->mapFileUseCount.erase(mi++);
                 LogPrint(BCLog::DB, "Flushed %s %dms\n", strFile,
                          GetTimeMillis() - nStart);
                 ret = true;
             }
         }
     }
 
     return ret;
 }
 
 bool CWalletDBWrapper::Rewrite(const char *pszSkip) {
     return CDB::Rewrite(*this, pszSkip);
 }
 
 bool CWalletDBWrapper::Backup(const std::string &strDest) {
     if (IsDummy()) {
         return false;
     }
     while (true) {
         {
             LOCK(cs_db);
             if (!env->mapFileUseCount.count(strFile) ||
                 env->mapFileUseCount[strFile] == 0) {
                 // Flush log data to the dat file
                 env->CloseDb(strFile);
                 env->CheckpointLSN(strFile);
                 env->mapFileUseCount.erase(strFile);
 
                 // Copy wallet file.
                 fs::path pathSrc = GetWalletDir() / strFile;
                 fs::path pathDest(strDest);
                 if (fs::is_directory(pathDest)) {
                     pathDest /= strFile;
                 }
 
                 try {
                     if (fs::equivalent(pathSrc, pathDest)) {
                         LogPrintf("cannot backup to wallet source file %s\n",
                                   pathDest.string());
                         return false;
                     }
 
                     fs::copy_file(pathSrc, pathDest,
                                   fs::copy_option::overwrite_if_exists);
                     LogPrintf("copied %s to %s\n", strFile, pathDest.string());
                     return true;
                 } catch (const fs::filesystem_error &e) {
                     LogPrintf("error copying %s to %s - %s\n", strFile,
                               pathDest.string(), e.what());
                     return false;
                 }
             }
         }
         MilliSleep(100);
     }
     return false;
 }
 
 void CWalletDBWrapper::Flush(bool shutdown) {
     if (!IsDummy()) {
         env->Flush(shutdown);
     }
 }
diff --git a/src/wallet/init.cpp b/src/wallet/init.cpp
index 894239849..90e5a9863 100644
--- a/src/wallet/init.cpp
+++ b/src/wallet/init.cpp
@@ -1,417 +1,434 @@
 // Copyright (c) 2009-2010 Satoshi Nakamoto
 // Copyright (c) 2009-2017 The Bitcoin Core developers
 // Copyright (c) 2018 The Bitcoin developers
 // Distributed under the MIT software license, see the accompanying
 // file COPYING or http://www.opensource.org/licenses/mit-license.php.
 
 #include <config.h>
 #include <init.h>
 #include <net.h>
 #include <util.h>
 #include <utilmoneystr.h>
 #include <validation.h>
 #include <wallet/rpcdump.h>
 #include <wallet/rpcwallet.h>
 #include <wallet/wallet.h>
 #include <wallet/walletutil.h>
 #include <walletinitinterface.h>
 
 class WalletInit : public WalletInitInterface {
 public:
     //! Return the wallets help message.
     void AddWalletOptions() const override;
 
     //! Wallets parameter interaction
     bool ParameterInteraction() const override;
 
     //! Register wallet RPCs.
     void RegisterRPC(CRPCTable &tableRPC) const override;
 
     //! Responsible for reading and validating the -wallet arguments and
     //! verifying the wallet database.
     //  This function will perform salvage on the wallet if requested, as long
     //  as only one wallet is being loaded (WalletParameterInteraction forbids
     //  -salvagewallet, -zapwallettxes or -upgradewallet with multiwallet).
     bool Verify(const CChainParams &chainParams) const override;
 
     //! Load wallet databases.
     bool Open(const CChainParams &chainParams) const override;
 
     //! Complete startup of wallets.
     void Start(CScheduler &scheduler) const override;
 
     //! Flush all wallets in preparation for shutdown.
     void Flush() const override;
 
     //! Stop all wallets. Wallets will be flushed first.
     void Stop() const override;
 
     //! Close all wallets.
     void Close() const override;
 };
 
 const WalletInitInterface &g_wallet_init_interface = WalletInit();
 
 void WalletInit::AddWalletOptions() const {
     gArgs.AddArg("-disablewallet",
                  _("Do not load the wallet and disable wallet RPC calls"),
                  false, OptionsCategory::WALLET);
     gArgs.AddArg("-keypool=<n>",
                  strprintf(_("Set key pool size to <n> (default: %u)"),
                            DEFAULT_KEYPOOL_SIZE),
                  false, OptionsCategory::WALLET);
     gArgs.AddArg("-fallbackfee=<amt>",
                  strprintf(_("A fee rate (in %s/kB) that will be used when fee "
                              "estimation has insufficient data (default: %s)"),
                            CURRENCY_UNIT, FormatMoney(DEFAULT_FALLBACK_FEE)),
                  false, OptionsCategory::WALLET);
     gArgs.AddArg(
         "-paytxfee=<amt>",
         strprintf(
             _("Fee (in %s/kB) to add to transactions you send (default: %s)"),
             CURRENCY_UNIT, FormatMoney(payTxFee.GetFeePerK())),
         false, OptionsCategory::WALLET);
     gArgs.AddArg(
         "-rescan",
         _("Rescan the block chain for missing wallet transactions on startup"),
         false, OptionsCategory::WALLET);
     gArgs.AddArg(
         "-salvagewallet",
         _("Attempt to recover private keys from a corrupt wallet on startup"),
         false, OptionsCategory::WALLET);
 
     gArgs.AddArg("-spendzeroconfchange",
                  strprintf(_("Spend unconfirmed change when sending "
                              "transactions (default: %d)"),
                            DEFAULT_SPEND_ZEROCONF_CHANGE),
                  false, OptionsCategory::WALLET);
     gArgs.AddArg("-upgradewallet",
                  _("Upgrade wallet to latest format on startup"), false,
                  OptionsCategory::WALLET);
     gArgs.AddArg(
         "-wallet=<path>",
         _("Specify wallet database path. Can be specified multiple times to "
           "load multiple wallets. Path is interpreted relative to <walletdir> "
-          "if it is not absolute, and will be created if it does not exist.") +
-            " " + strprintf(_("(default: %s)"), DEFAULT_WALLET_DAT),
+          "if it is not absolute, and will be created if it does not exist (as "
+          "a directory containing a wallet.dat file and log files). For "
+          "backwards compatibility this will also accept names of existing "
+          "data files in <walletdir>.)"),
         false, OptionsCategory::WALLET);
     gArgs.AddArg("-walletbroadcast",
                  _("Make the wallet broadcast transactions") + " " +
                      strprintf(_("(default: %d)"), DEFAULT_WALLETBROADCAST),
                  false, OptionsCategory::WALLET);
     gArgs.AddArg("-walletdir=<dir>",
                  _("Specify directory to hold wallets (default: "
                    "<datadir>/wallets if it exists, otherwise <datadir>)"),
                  false, OptionsCategory::WALLET);
     gArgs.AddArg("-walletnotify=<cmd>",
                  _("Execute command when a wallet transaction changes (%s in "
                    "cmd is replaced by TxID)"),
                  false, OptionsCategory::WALLET);
     gArgs.AddArg("-zapwallettxes=<mode>",
                  _("Delete all wallet transactions and only recover those "
                    "parts of the blockchain through -rescan on startup") +
                      " " +
                      _("(1 = keep tx meta data e.g. account owner and payment "
                        "request information, 2 = drop tx meta data)"),
                  false, OptionsCategory::WALLET);
 
     gArgs.AddArg("-dblogsize=<n>",
                  strprintf("Flush wallet database activity from memory to disk "
                            "log every <n> megabytes (default: %u)",
                            DEFAULT_WALLET_DBLOGSIZE),
                  true, OptionsCategory::WALLET_DEBUG_TEST);
     gArgs.AddArg(
         "-flushwallet",
         strprintf("Run a thread to flush wallet periodically (default: %d)",
                   DEFAULT_FLUSHWALLET),
         true, OptionsCategory::WALLET_DEBUG_TEST);
     gArgs.AddArg("-privdb",
                  strprintf("Sets the DB_PRIVATE flag in the wallet db "
                            "environment (default: %d)",
                            DEFAULT_WALLET_PRIVDB),
                  true, OptionsCategory::WALLET_DEBUG_TEST);
     gArgs.AddArg("-walletrejectlongchains",
                  strprintf(_("Wallet will not create transactions that violate "
                              "mempool chain limits (default: %d)"),
                            DEFAULT_WALLET_REJECT_LONG_CHAINS),
                  true, OptionsCategory::WALLET_DEBUG_TEST);
 }
 
 bool WalletInit::ParameterInteraction() const {
     CFeeRate minRelayTxFee = GetConfig().GetMinFeePerKB();
 
-    gArgs.SoftSetArg("-wallet", DEFAULT_WALLET_DAT);
+    gArgs.SoftSetArg("-wallet", "");
     const bool is_multiwallet = gArgs.GetArgs("-wallet").size() > 1;
 
     if (gArgs.GetBoolArg("-disablewallet", DEFAULT_DISABLE_WALLET)) {
         return true;
     }
 
     if (gArgs.GetBoolArg("-blocksonly", DEFAULT_BLOCKSONLY) &&
         gArgs.SoftSetBoolArg("-walletbroadcast", false)) {
         LogPrintf("%s: parameter interaction: -blocksonly=1 -> setting "
                   "-walletbroadcast=0\n",
                   __func__);
     }
 
     if (gArgs.GetBoolArg("-salvagewallet", false) &&
         gArgs.SoftSetBoolArg("-rescan", true)) {
         if (is_multiwallet) {
             return InitError(
                 strprintf("%s is only allowed with a single wallet file",
                           "-salvagewallet"));
         }
         // Rewrite just private keys: rescan to find transactions
         LogPrintf("%s: parameter interaction: -salvagewallet=1 -> setting "
                   "-rescan=1\n",
                   __func__);
     }
 
     int zapwallettxes = gArgs.GetArg("-zapwallettxes", 0);
     // -zapwallettxes implies dropping the mempool on startup
     if (zapwallettxes != 0 && gArgs.SoftSetBoolArg("-persistmempool", false)) {
         LogPrintf("%s: parameter interaction: -zapwallettxes=%s -> setting "
                   "-persistmempool=0\n",
                   __func__, zapwallettxes);
     }
 
     // -zapwallettxes implies a rescan
     if (zapwallettxes != 0) {
         if (is_multiwallet) {
             return InitError(
                 strprintf("%s is only allowed with a single wallet file",
                           "-zapwallettxes"));
         }
         if (gArgs.SoftSetBoolArg("-rescan", true)) {
             LogPrintf("%s: parameter interaction: -zapwallettxes=%s -> setting "
                       "-rescan=1\n",
                       __func__, zapwallettxes);
         }
         LogPrintf("%s: parameter interaction: -zapwallettxes=<mode> -> setting "
                   "-rescan=1\n",
                   __func__);
     }
 
     if (is_multiwallet) {
         if (gArgs.GetBoolArg("-upgradewallet", false)) {
             return InitError(
                 strprintf("%s is only allowed with a single wallet file",
                           "-upgradewallet"));
         }
     }
 
     if (gArgs.GetBoolArg("-sysperms", false)) {
         return InitError("-sysperms is not allowed in combination with enabled "
                          "wallet functionality");
     }
 
     if (gArgs.GetArg("-prune", 0) && gArgs.GetBoolArg("-rescan", false)) {
         return InitError(
             _("Rescans are not possible in pruned mode. You will need to use "
               "-reindex which will download the whole blockchain again."));
     }
 
     if (minRelayTxFee.GetFeePerK() > HIGH_TX_FEE_PER_KB) {
         InitWarning(
             AmountHighWarn("-minrelaytxfee") + " " +
             _("The wallet will avoid paying less than the minimum relay fee."));
     }
 
     if (gArgs.IsArgSet("-fallbackfee")) {
         Amount nFeePerK = Amount::zero();
         if (!ParseMoney(gArgs.GetArg("-fallbackfee", ""), nFeePerK)) {
             return InitError(
                 strprintf(_("Invalid amount for -fallbackfee=<amount>: '%s'"),
                           gArgs.GetArg("-fallbackfee", "")));
         }
 
         if (nFeePerK > HIGH_TX_FEE_PER_KB) {
             InitWarning(AmountHighWarn("-fallbackfee") + " " +
                         _("This is the transaction fee you may pay when fee "
                           "estimates are not available."));
         }
 
         CWallet::fallbackFee = CFeeRate(nFeePerK);
     }
 
     if (gArgs.IsArgSet("-paytxfee")) {
         Amount nFeePerK = Amount::zero();
         if (!ParseMoney(gArgs.GetArg("-paytxfee", ""), nFeePerK)) {
             return InitError(
                 AmountErrMsg("paytxfee", gArgs.GetArg("-paytxfee", "")));
         }
 
         if (nFeePerK > HIGH_TX_FEE_PER_KB) {
             InitWarning(AmountHighWarn("-paytxfee") + " " +
                         _("This is the transaction fee you will pay if you "
                           "send a transaction."));
         }
 
         payTxFee = CFeeRate(nFeePerK, 1000);
         if (payTxFee < minRelayTxFee) {
             return InitError(strprintf(
                 _("Invalid amount for -paytxfee=<amount>: '%s' (must "
                   "be at least %s)"),
                 gArgs.GetArg("-paytxfee", ""), minRelayTxFee.ToString()));
         }
     }
 
     if (gArgs.IsArgSet("-maxtxfee")) {
         Amount nMaxFee = Amount::zero();
         if (!ParseMoney(gArgs.GetArg("-maxtxfee", ""), nMaxFee)) {
             return InitError(
                 AmountErrMsg("maxtxfee", gArgs.GetArg("-maxtxfee", "")));
         }
 
         if (nMaxFee > HIGH_MAX_TX_FEE) {
             InitWarning(_("-maxtxfee is set very high! Fees this large could "
                           "be paid on a single transaction."));
         }
 
         maxTxFee = nMaxFee;
         if (CFeeRate(maxTxFee, 1000) < minRelayTxFee) {
             return InitError(strprintf(
                 _("Invalid amount for -maxtxfee=<amount>: '%s' (must "
                   "be at least the minrelay fee of %s to prevent "
                   "stuck transactions)"),
                 gArgs.GetArg("-maxtxfee", ""), minRelayTxFee.ToString()));
         }
     }
 
     bSpendZeroConfChange =
         gArgs.GetBoolArg("-spendzeroconfchange", DEFAULT_SPEND_ZEROCONF_CHANGE);
 
     g_address_type = OutputType::DEFAULT;
     g_change_type = OutputType::DEFAULT;
 
     return true;
 }
 
 void WalletInit::RegisterRPC(CRPCTable &t) const {
     if (gArgs.GetBoolArg("-disablewallet", DEFAULT_DISABLE_WALLET)) {
         return;
     }
 
     RegisterWalletRPCCommands(t);
     RegisterDumpRPCCommands(t);
 }
 
 bool WalletInit::Verify(const CChainParams &chainParams) const {
     if (gArgs.GetBoolArg("-disablewallet", DEFAULT_DISABLE_WALLET)) {
         return true;
     }
 
     if (gArgs.IsArgSet("-walletdir")) {
         fs::path wallet_dir = gArgs.GetArg("-walletdir", "");
         if (!fs::exists(wallet_dir)) {
             return InitError(
                 strprintf(_("Specified -walletdir \"%s\" does not exist"),
                           wallet_dir.string()));
         } else if (!fs::is_directory(wallet_dir)) {
             return InitError(
                 strprintf(_("Specified -walletdir \"%s\" is not a directory"),
                           wallet_dir.string()));
         } else if (!wallet_dir.is_absolute()) {
             return InitError(
                 strprintf(_("Specified -walletdir \"%s\" is a relative path"),
                           wallet_dir.string()));
         }
     }
 
     LogPrintf("Using wallet directory %s\n", GetWalletDir().string());
 
     uiInterface.InitMessage(_("Verifying wallet(s)..."));
 
     // Keep track of each wallet absolute path to detect duplicates.
     std::set<fs::path> wallet_paths;
 
     for (const std::string &walletFile : gArgs.GetArgs("-wallet")) {
+        // Do some checking on wallet path. It should be either a:
+        //
+        // 1. Path where a directory can be created.
+        // 2. Path to an existing directory.
+        // 3. Path to a symlink to a directory.
+        // 4. For backwards compatibility, the name of a data file in
+        // -walletdir.
         fs::path wallet_path = fs::absolute(walletFile, GetWalletDir());
-
-        if (fs::exists(wallet_path) && (!fs::is_regular_file(wallet_path) ||
-                                        fs::is_symlink(wallet_path))) {
-            return InitError(strprintf(_("Error loading wallet %s. -wallet "
-                                         "filename must be a regular file."),
-                                       walletFile));
+        fs::file_type path_type = fs::symlink_status(wallet_path).type();
+        if (!(path_type == fs::file_not_found ||
+              path_type == fs::directory_file ||
+              (path_type == fs::symlink_file &&
+               fs::is_directory(wallet_path)) ||
+              (path_type == fs::regular_file &&
+               fs::path(walletFile).filename() == walletFile))) {
+            return InitError(strprintf(
+                _("Invalid -wallet path '%s'. -wallet path should point to a "
+                  "directory where wallet.dat and database/log.?????????? "
+                  "files can be stored, a location where such a directory "
+                  "could be created, or (for backwards compatibility) the name "
+                  "of an existing data file in -walletdir (%s)"),
+                walletFile, GetWalletDir()));
         }
 
         if (!wallet_paths.insert(wallet_path).second) {
             return InitError(strprintf(_("Error loading wallet %s. Duplicate "
                                          "-wallet filename specified."),
                                        walletFile));
         }
 
         std::string strError;
         if (!CWalletDB::VerifyEnvironment(wallet_path, strError)) {
             return InitError(strError);
         }
 
         if (gArgs.GetBoolArg("-salvagewallet", false)) {
             // Recover readable keypairs:
             CWallet dummyWallet(chainParams, "dummy",
                                 CWalletDBWrapper::CreateDummy());
             std::string backup_filename;
             if (!CWalletDB::Recover(wallet_path, (void *)&dummyWallet,
                                     CWalletDB::RecoverKeysOnlyFilter,
                                     backup_filename)) {
                 return false;
             }
         }
 
         std::string strWarning;
         bool dbV =
             CWalletDB::VerifyDatabaseFile(wallet_path, strWarning, strError);
         if (!strWarning.empty()) {
             InitWarning(strWarning);
         }
         if (!dbV) {
             InitError(strError);
             return false;
         }
     }
 
     return true;
 }
 
 bool WalletInit::Open(const CChainParams &chainParams) const {
     if (gArgs.GetBoolArg("-disablewallet", DEFAULT_DISABLE_WALLET)) {
         LogPrintf("Wallet disabled!\n");
         return true;
     }
 
     for (const std::string &walletFile : gArgs.GetArgs("-wallet")) {
         CWallet *const pwallet = CWallet::CreateWalletFromFile(
             chainParams, walletFile, fs::absolute(walletFile, GetWalletDir()));
         if (!pwallet) {
             return false;
         }
         vpwallets.push_back(pwallet);
     }
 
     return true;
 }
 
 void WalletInit::Start(CScheduler &scheduler) const {
     for (CWalletRef pwallet : vpwallets) {
         pwallet->postInitProcess(scheduler);
     }
 }
 
 void WalletInit::Flush() const {
     for (CWalletRef pwallet : vpwallets) {
         pwallet->Flush(false);
     }
 }
 
 void WalletInit::Stop() const {
     for (CWalletRef pwallet : vpwallets) {
         pwallet->Flush(true);
     }
 }
 
 void WalletInit::Close() const {
     for (CWalletRef pwallet : vpwallets) {
         delete pwallet;
     }
     vpwallets.clear();
 }
diff --git a/src/wallet/wallet.cpp b/src/wallet/wallet.cpp
index ac921d4fa..3a411d049 100644
--- a/src/wallet/wallet.cpp
+++ b/src/wallet/wallet.cpp
@@ -1,4570 +1,4569 @@
 // Copyright (c) 2009-2010 Satoshi Nakamoto
 // Copyright (c) 2009-2016 The Bitcoin Core developers
 // Distributed under the MIT software license, see the accompanying
 // file COPYING or http://www.opensource.org/licenses/mit-license.php.
 
 #include <wallet/wallet.h>
 
 #include <chain.h>
 #include <checkpoints.h>
 #include <config.h>
 #include <consensus/consensus.h>
 #include <consensus/validation.h>
 #include <dstencode.h>
 #include <fs.h>
 #include <init.h>
 #include <key.h>
 #include <keystore.h>
 #include <net.h>
 #include <policy/policy.h>
 #include <primitives/block.h>
 #include <primitives/transaction.h>
 #include <rpc/server.h> // for IsDeprecatedRPCEnabled
 #include <scheduler.h>
 #include <script/script.h>
 #include <script/sighashtype.h>
 #include <script/sign.h>
 #include <timedata.h>
 #include <txmempool.h>
 #include <ui_interface.h>
 #include <util.h>
 #include <utilmoneystr.h>
 #include <validation.h>
 #include <wallet/coincontrol.h>
 #include <wallet/fees.h>
 #include <wallet/finaltx.h>
 
 #include <boost/algorithm/string/replace.hpp>
 
 #include <cassert>
 #include <future>
 
 std::vector<CWalletRef> vpwallets;
 
 /** Transaction fee set by the user */
 CFeeRate payTxFee(DEFAULT_TRANSACTION_FEE);
 bool bSpendZeroConfChange = DEFAULT_SPEND_ZEROCONF_CHANGE;
 
 OutputType g_address_type = OutputType::NONE;
 OutputType g_change_type = OutputType::NONE;
 
-const char *DEFAULT_WALLET_DAT = "wallet.dat";
 const uint32_t BIP32_HARDENED_KEY_LIMIT = 0x80000000;
 
 /**
  * If fee estimation does not have enough data to provide estimates, use this
  * fee instead. Has no effect if not using fee estimation.
  * Override with -fallbackfee
  */
 CFeeRate CWallet::fallbackFee = CFeeRate(DEFAULT_FALLBACK_FEE);
 
 const uint256 CMerkleTx::ABANDON_HASH(uint256S(
     "0000000000000000000000000000000000000000000000000000000000000001"));
 
 /** @defgroup mapWallet
  *
  * @{
  */
 
 struct CompareValueOnly {
     bool operator()(const CInputCoin &t1, const CInputCoin &t2) const {
         return t1.txout.nValue < t2.txout.nValue;
     }
 };
 
 std::string COutput::ToString() const {
     return strprintf("COutput(%s, %d, %d) [%s]", tx->GetId().ToString(), i,
                      nDepth, FormatMoney(tx->tx->vout[i].nValue));
 }
 
 class CAffectedKeysVisitor : public boost::static_visitor<void> {
 private:
     const CKeyStore &keystore;
     std::vector<CKeyID> &vKeys;
 
 public:
     CAffectedKeysVisitor(const CKeyStore &keystoreIn,
                          std::vector<CKeyID> &vKeysIn)
         : keystore(keystoreIn), vKeys(vKeysIn) {}
 
     void Process(const CScript &script) {
         txnouttype type;
         std::vector<CTxDestination> vDest;
         int nRequired;
         if (ExtractDestinations(script, type, vDest, nRequired)) {
             for (const CTxDestination &dest : vDest) {
                 boost::apply_visitor(*this, dest);
             }
         }
     }
 
     void operator()(const CKeyID &keyId) {
         if (keystore.HaveKey(keyId)) {
             vKeys.push_back(keyId);
         }
     }
 
     void operator()(const CScriptID &scriptId) {
         CScript script;
         if (keystore.GetCScript(scriptId, script)) {
             Process(script);
         }
     }
 
     void operator()(const CNoDestination &none) {}
 };
 
 const CWalletTx *CWallet::GetWalletTx(const TxId &txid) const {
     LOCK(cs_wallet);
     std::map<TxId, CWalletTx>::const_iterator it = mapWallet.find(txid);
     if (it == mapWallet.end()) {
         return nullptr;
     }
 
     return &(it->second);
 }
 
 CPubKey CWallet::GenerateNewKey(CWalletDB &walletdb, bool internal) {
     // mapKeyMetadata
     AssertLockHeld(cs_wallet);
     // default to compressed public keys if we want 0.6.0 wallets
     bool fCompressed = CanSupportFeature(FEATURE_COMPRPUBKEY);
 
     CKey secret;
 
     // Create new metadata
     int64_t nCreationTime = GetTime();
     CKeyMetadata metadata(nCreationTime);
 
     // use HD key derivation if HD was enabled during wallet creation
     if (IsHDEnabled()) {
         DeriveNewChildKey(
             walletdb, metadata, secret,
             (CanSupportFeature(FEATURE_HD_SPLIT) ? internal : false));
     } else {
         secret.MakeNewKey(fCompressed);
     }
 
     // Compressed public keys were introduced in version 0.6.0
     if (fCompressed) {
         SetMinVersion(FEATURE_COMPRPUBKEY);
     }
 
     CPubKey pubkey = secret.GetPubKey();
     assert(secret.VerifyPubKey(pubkey));
 
     mapKeyMetadata[pubkey.GetID()] = metadata;
     UpdateTimeFirstKey(nCreationTime);
 
     if (!AddKeyPubKeyWithDB(walletdb, secret, pubkey)) {
         throw std::runtime_error(std::string(__func__) + ": AddKey failed");
     }
 
     return pubkey;
 }
 
 void CWallet::DeriveNewChildKey(CWalletDB &walletdb, CKeyMetadata &metadata,
                                 CKey &secret, bool internal) {
     // for now we use a fixed keypath scheme of m/0'/0'/k
     // master key seed (256bit)
     CKey key;
     // hd master key
     CExtKey masterKey;
     // key at m/0'
     CExtKey accountKey;
     // key at m/0'/0' (external) or m/0'/1' (internal)
     CExtKey chainChildKey;
     // key at m/0'/0'/<n>'
     CExtKey childKey;
 
     // try to get the master key
     if (!GetKey(hdChain.masterKeyID, key)) {
         throw std::runtime_error(std::string(__func__) +
                                  ": Master key not found");
     }
 
     masterKey.SetMaster(key.begin(), key.size());
 
     // derive m/0'
     // use hardened derivation (child keys >= 0x80000000 are hardened after
     // bip32)
     masterKey.Derive(accountKey, BIP32_HARDENED_KEY_LIMIT);
 
     // derive m/0'/0' (external chain) OR m/0'/1' (internal chain)
     assert(internal ? CanSupportFeature(FEATURE_HD_SPLIT) : true);
     accountKey.Derive(chainChildKey,
                       BIP32_HARDENED_KEY_LIMIT + (internal ? 1 : 0));
 
     // derive child key at next index, skip keys already known to the wallet
     do {
         // always derive hardened keys
         // childIndex | BIP32_HARDENED_KEY_LIMIT = derive childIndex in hardened
         // child-index-range
         // example: 1 | BIP32_HARDENED_KEY_LIMIT == 0x80000001 == 2147483649
         if (internal) {
             chainChildKey.Derive(childKey, hdChain.nInternalChainCounter |
                                                BIP32_HARDENED_KEY_LIMIT);
             metadata.hdKeypath = "m/0'/1'/" +
                                  std::to_string(hdChain.nInternalChainCounter) +
                                  "'";
             hdChain.nInternalChainCounter++;
         } else {
             chainChildKey.Derive(childKey, hdChain.nExternalChainCounter |
                                                BIP32_HARDENED_KEY_LIMIT);
             metadata.hdKeypath = "m/0'/0'/" +
                                  std::to_string(hdChain.nExternalChainCounter) +
                                  "'";
             hdChain.nExternalChainCounter++;
         }
     } while (HaveKey(childKey.key.GetPubKey().GetID()));
     secret = childKey.key;
     metadata.hdMasterKeyID = hdChain.masterKeyID;
     // update the chain model in the database
     if (!walletdb.WriteHDChain(hdChain)) {
         throw std::runtime_error(std::string(__func__) +
                                  ": Writing HD chain model failed");
     }
 }
 
 bool CWallet::AddKeyPubKeyWithDB(CWalletDB &walletdb, const CKey &secret,
                                  const CPubKey &pubkey) {
     // mapKeyMetadata
     AssertLockHeld(cs_wallet);
 
     // CCryptoKeyStore has no concept of wallet databases, but calls
     // AddCryptedKey
     // which is overridden below.  To avoid flushes, the database handle is
     // tunneled through to it.
     bool needsDB = !pwalletdbEncryption;
     if (needsDB) {
         pwalletdbEncryption = &walletdb;
     }
     if (!CCryptoKeyStore::AddKeyPubKey(secret, pubkey)) {
         if (needsDB) {
             pwalletdbEncryption = nullptr;
         }
         return false;
     }
 
     if (needsDB) {
         pwalletdbEncryption = nullptr;
     }
 
     // Check if we need to remove from watch-only.
     CScript script;
     script = GetScriptForDestination(pubkey.GetID());
     if (HaveWatchOnly(script)) {
         RemoveWatchOnly(script);
     }
 
     script = GetScriptForRawPubKey(pubkey);
     if (HaveWatchOnly(script)) {
         RemoveWatchOnly(script);
     }
 
     if (IsCrypted()) {
         return true;
     }
 
     return walletdb.WriteKey(pubkey, secret.GetPrivKey(),
                              mapKeyMetadata[pubkey.GetID()]);
 }
 
 bool CWallet::AddKeyPubKey(const CKey &secret, const CPubKey &pubkey) {
     CWalletDB walletdb(*dbw);
     return CWallet::AddKeyPubKeyWithDB(walletdb, secret, pubkey);
 }
 
 bool CWallet::AddCryptedKey(const CPubKey &vchPubKey,
                             const std::vector<uint8_t> &vchCryptedSecret) {
     if (!CCryptoKeyStore::AddCryptedKey(vchPubKey, vchCryptedSecret)) {
         return false;
     }
 
     LOCK(cs_wallet);
     if (pwalletdbEncryption) {
         return pwalletdbEncryption->WriteCryptedKey(
             vchPubKey, vchCryptedSecret, mapKeyMetadata[vchPubKey.GetID()]);
     }
 
     return CWalletDB(*dbw).WriteCryptedKey(vchPubKey, vchCryptedSecret,
                                            mapKeyMetadata[vchPubKey.GetID()]);
 }
 
 bool CWallet::LoadKeyMetadata(const CKeyID &keyID, const CKeyMetadata &meta) {
     // mapKeyMetadata
     AssertLockHeld(cs_wallet);
     UpdateTimeFirstKey(meta.nCreateTime);
     mapKeyMetadata[keyID] = meta;
     return true;
 }
 
 bool CWallet::LoadScriptMetadata(const CScriptID &script_id,
                                  const CKeyMetadata &meta) {
     // m_script_metadata
     AssertLockHeld(cs_wallet);
     UpdateTimeFirstKey(meta.nCreateTime);
     m_script_metadata[script_id] = meta;
     return true;
 }
 
 bool CWallet::LoadCryptedKey(const CPubKey &vchPubKey,
                              const std::vector<uint8_t> &vchCryptedSecret) {
     return CCryptoKeyStore::AddCryptedKey(vchPubKey, vchCryptedSecret);
 }
 
 /**
  * Update wallet first key creation time. This should be called whenever keys
  * are added to the wallet, with the oldest key creation time.
  */
 void CWallet::UpdateTimeFirstKey(int64_t nCreateTime) {
     AssertLockHeld(cs_wallet);
     if (nCreateTime <= 1) {
         // Cannot determine birthday information, so set the wallet birthday to
         // the beginning of time.
         nTimeFirstKey = 1;
     } else if (!nTimeFirstKey || nCreateTime < nTimeFirstKey) {
         nTimeFirstKey = nCreateTime;
     }
 }
 
 bool CWallet::AddCScript(const CScript &redeemScript) {
     if (!CCryptoKeyStore::AddCScript(redeemScript)) {
         return false;
     }
 
     return CWalletDB(*dbw).WriteCScript(Hash160(redeemScript), redeemScript);
 }
 
 bool CWallet::LoadCScript(const CScript &redeemScript) {
     /**
      * A sanity check was added in pull #3843 to avoid adding redeemScripts that
      * never can be redeemed. However, old wallets may still contain these. Do
      * not add them to the wallet and warn.
      */
     if (redeemScript.size() > MAX_SCRIPT_ELEMENT_SIZE) {
         std::string strAddr = EncodeDestination(CScriptID(redeemScript));
         LogPrintf("%s: Warning: This wallet contains a redeemScript of size %i "
                   "which exceeds maximum size %i thus can never be redeemed. "
                   "Do not use address %s.\n",
                   __func__, redeemScript.size(), MAX_SCRIPT_ELEMENT_SIZE,
                   strAddr);
         return true;
     }
 
     return CCryptoKeyStore::AddCScript(redeemScript);
 }
 
 bool CWallet::AddWatchOnly(const CScript &dest) {
     if (!CCryptoKeyStore::AddWatchOnly(dest)) {
         return false;
     }
 
     const CKeyMetadata &meta = m_script_metadata[CScriptID(dest)];
     UpdateTimeFirstKey(meta.nCreateTime);
     NotifyWatchonlyChanged(true);
     return CWalletDB(*dbw).WriteWatchOnly(dest, meta);
 }
 
 bool CWallet::AddWatchOnly(const CScript &dest, int64_t nCreateTime) {
     m_script_metadata[CScriptID(dest)].nCreateTime = nCreateTime;
     return AddWatchOnly(dest);
 }
 
 bool CWallet::RemoveWatchOnly(const CScript &dest) {
     AssertLockHeld(cs_wallet);
     if (!CCryptoKeyStore::RemoveWatchOnly(dest)) {
         return false;
     }
 
     if (!HaveWatchOnly()) {
         NotifyWatchonlyChanged(false);
     }
 
     return CWalletDB(*dbw).EraseWatchOnly(dest);
 }
 
 bool CWallet::LoadWatchOnly(const CScript &dest) {
     return CCryptoKeyStore::AddWatchOnly(dest);
 }
 
 bool CWallet::Unlock(const SecureString &strWalletPassphrase) {
     CCrypter crypter;
     CKeyingMaterial _vMasterKey;
 
     LOCK(cs_wallet);
     for (const MasterKeyMap::value_type &pMasterKey : mapMasterKeys) {
         if (!crypter.SetKeyFromPassphrase(
                 strWalletPassphrase, pMasterKey.second.vchSalt,
                 pMasterKey.second.nDeriveIterations,
                 pMasterKey.second.nDerivationMethod)) {
             return false;
         }
 
         if (!crypter.Decrypt(pMasterKey.second.vchCryptedKey, _vMasterKey)) {
             // try another master key
             continue;
         }
 
         if (CCryptoKeyStore::Unlock(_vMasterKey)) {
             return true;
         }
     }
 
     return false;
 }
 
 bool CWallet::ChangeWalletPassphrase(
     const SecureString &strOldWalletPassphrase,
     const SecureString &strNewWalletPassphrase) {
     bool fWasLocked = IsLocked();
 
     LOCK(cs_wallet);
     Lock();
 
     CCrypter crypter;
     CKeyingMaterial _vMasterKey;
     for (MasterKeyMap::value_type &pMasterKey : mapMasterKeys) {
         if (!crypter.SetKeyFromPassphrase(
                 strOldWalletPassphrase, pMasterKey.second.vchSalt,
                 pMasterKey.second.nDeriveIterations,
                 pMasterKey.second.nDerivationMethod)) {
             return false;
         }
 
         if (!crypter.Decrypt(pMasterKey.second.vchCryptedKey, _vMasterKey)) {
             return false;
         }
 
         if (CCryptoKeyStore::Unlock(_vMasterKey)) {
             int64_t nStartTime = GetTimeMillis();
             crypter.SetKeyFromPassphrase(strNewWalletPassphrase,
                                          pMasterKey.second.vchSalt,
                                          pMasterKey.second.nDeriveIterations,
                                          pMasterKey.second.nDerivationMethod);
             pMasterKey.second.nDeriveIterations =
                 pMasterKey.second.nDeriveIterations *
                 (100 / ((double)(GetTimeMillis() - nStartTime)));
 
             nStartTime = GetTimeMillis();
             crypter.SetKeyFromPassphrase(strNewWalletPassphrase,
                                          pMasterKey.second.vchSalt,
                                          pMasterKey.second.nDeriveIterations,
                                          pMasterKey.second.nDerivationMethod);
             pMasterKey.second.nDeriveIterations =
                 (pMasterKey.second.nDeriveIterations +
                  pMasterKey.second.nDeriveIterations * 100 /
                      double(GetTimeMillis() - nStartTime)) /
                 2;
 
             if (pMasterKey.second.nDeriveIterations < 25000) {
                 pMasterKey.second.nDeriveIterations = 25000;
             }
 
             LogPrintf(
                 "Wallet passphrase changed to an nDeriveIterations of %i\n",
                 pMasterKey.second.nDeriveIterations);
 
             if (!crypter.SetKeyFromPassphrase(
                     strNewWalletPassphrase, pMasterKey.second.vchSalt,
                     pMasterKey.second.nDeriveIterations,
                     pMasterKey.second.nDerivationMethod)) {
                 return false;
             }
 
             if (!crypter.Encrypt(_vMasterKey,
                                  pMasterKey.second.vchCryptedKey)) {
                 return false;
             }
 
             CWalletDB(*dbw).WriteMasterKey(pMasterKey.first, pMasterKey.second);
             if (fWasLocked) {
                 Lock();
             }
 
             return true;
         }
     }
 
     return false;
 }
 
 void CWallet::ChainStateFlushed(const CBlockLocator &loc) {
     CWalletDB walletdb(*dbw);
     walletdb.WriteBestBlock(loc);
 }
 
 bool CWallet::SetMinVersion(enum WalletFeature nVersion, CWalletDB *pwalletdbIn,
                             bool fExplicit) {
     // nWalletVersion
     LOCK(cs_wallet);
     if (nWalletVersion >= nVersion) {
         return true;
     }
 
     // When doing an explicit upgrade, if we pass the max version permitted,
     // upgrade all the way.
     if (fExplicit && nVersion > nWalletMaxVersion) {
         nVersion = FEATURE_LATEST;
     }
 
     nWalletVersion = nVersion;
 
     if (nVersion > nWalletMaxVersion) {
         nWalletMaxVersion = nVersion;
     }
 
     CWalletDB *pwalletdb = pwalletdbIn ? pwalletdbIn : new CWalletDB(*dbw);
     if (nWalletVersion > 40000) {
         pwalletdb->WriteMinVersion(nWalletVersion);
     }
 
     if (!pwalletdbIn) {
         delete pwalletdb;
     }
 
     return true;
 }
 
 bool CWallet::SetMaxVersion(int nVersion) {
     // nWalletVersion, nWalletMaxVersion
     LOCK(cs_wallet);
 
     // Cannot downgrade below current version
     if (nWalletVersion > nVersion) {
         return false;
     }
 
     nWalletMaxVersion = nVersion;
 
     return true;
 }
 
 std::set<TxId> CWallet::GetConflicts(const TxId &txid) const {
     std::set<TxId> result;
     AssertLockHeld(cs_wallet);
 
     std::map<TxId, CWalletTx>::const_iterator it = mapWallet.find(txid);
     if (it == mapWallet.end()) {
         return result;
     }
 
     const CWalletTx &wtx = it->second;
 
     std::pair<TxSpends::const_iterator, TxSpends::const_iterator> range;
 
     for (const CTxIn &txin : wtx.tx->vin) {
         if (mapTxSpends.count(txin.prevout) <= 1) {
             // No conflict if zero or one spends.
             continue;
         }
 
         range = mapTxSpends.equal_range(txin.prevout);
         for (TxSpends::const_iterator _it = range.first; _it != range.second;
              ++_it) {
             result.insert(_it->second);
         }
     }
 
     return result;
 }
 
 bool CWallet::HasWalletSpend(const TxId &txid) const {
     AssertLockHeld(cs_wallet);
     auto iter = mapTxSpends.lower_bound(COutPoint(txid, 0));
     return (iter != mapTxSpends.end() && iter->first.GetTxId() == txid);
 }
 
 void CWallet::Flush(bool shutdown) {
     dbw->Flush(shutdown);
 }
 
 void CWallet::SyncMetaData(
     std::pair<TxSpends::iterator, TxSpends::iterator> range) {
     // We want all the wallet transactions in range to have the same metadata as
     // the oldest (smallest nOrderPos).
     // So: find smallest nOrderPos:
 
     int nMinOrderPos = std::numeric_limits<int>::max();
     const CWalletTx *copyFrom = nullptr;
     for (TxSpends::iterator it = range.first; it != range.second; ++it) {
         const CWalletTx *wtx = &mapWallet.at(it->second);
         if (wtx->nOrderPos < nMinOrderPos) {
             nMinOrderPos = wtx->nOrderPos;
             copyFrom = wtx;
         }
     }
 
     // Now copy data from copyFrom to rest:
     for (TxSpends::iterator it = range.first; it != range.second; ++it) {
         const TxId &txid = it->second;
         CWalletTx *copyTo = &mapWallet.at(txid);
         if (copyFrom == copyTo) {
             continue;
         }
 
         assert(
             copyFrom &&
             "Oldest wallet transaction in range assumed to have been found.");
 
         if (!copyFrom->IsEquivalentTo(*copyTo)) {
             continue;
         }
 
         copyTo->mapValue = copyFrom->mapValue;
         copyTo->vOrderForm = copyFrom->vOrderForm;
         // fTimeReceivedIsTxTime not copied on purpose nTimeReceived not copied
         // on purpose.
         copyTo->nTimeSmart = copyFrom->nTimeSmart;
         copyTo->fFromMe = copyFrom->fFromMe;
         copyTo->strFromAccount = copyFrom->strFromAccount;
         // nOrderPos not copied on purpose cached members not copied on purpose.
     }
 }
 
 /**
  * Outpoint is spent if any non-conflicted transaction, spends it:
  */
 bool CWallet::IsSpent(const TxId &txid, uint32_t n) const {
     const COutPoint outpoint(txid, n);
     std::pair<TxSpends::const_iterator, TxSpends::const_iterator> range =
         mapTxSpends.equal_range(outpoint);
 
     for (TxSpends::const_iterator it = range.first; it != range.second; ++it) {
         const TxId &wtxid = it->second;
         std::map<TxId, CWalletTx>::const_iterator mit = mapWallet.find(wtxid);
         if (mit != mapWallet.end()) {
             int depth = mit->second.GetDepthInMainChain();
             if (depth > 0 || (depth == 0 && !mit->second.isAbandoned())) {
                 // Spent
                 return true;
             }
         }
     }
 
     return false;
 }
 
 void CWallet::AddToSpends(const COutPoint &outpoint, const TxId &wtxid) {
     mapTxSpends.insert(std::make_pair(outpoint, wtxid));
 
     std::pair<TxSpends::iterator, TxSpends::iterator> range;
     range = mapTxSpends.equal_range(outpoint);
     SyncMetaData(range);
 }
 
 void CWallet::AddToSpends(const TxId &wtxid) {
     auto it = mapWallet.find(wtxid);
     assert(it != mapWallet.end());
     CWalletTx &thisTx = it->second;
     // Coinbases don't spend anything!
     if (thisTx.IsCoinBase()) {
         return;
     }
 
     for (const CTxIn &txin : thisTx.tx->vin) {
         AddToSpends(txin.prevout, wtxid);
     }
 }
 
 bool CWallet::EncryptWallet(const SecureString &strWalletPassphrase) {
     if (IsCrypted()) {
         return false;
     }
 
     CKeyingMaterial _vMasterKey;
 
     _vMasterKey.resize(WALLET_CRYPTO_KEY_SIZE);
     GetStrongRandBytes(&_vMasterKey[0], WALLET_CRYPTO_KEY_SIZE);
 
     CMasterKey kMasterKey;
 
     kMasterKey.vchSalt.resize(WALLET_CRYPTO_SALT_SIZE);
     GetStrongRandBytes(&kMasterKey.vchSalt[0], WALLET_CRYPTO_SALT_SIZE);
 
     CCrypter crypter;
     int64_t nStartTime = GetTimeMillis();
     crypter.SetKeyFromPassphrase(strWalletPassphrase, kMasterKey.vchSalt, 25000,
                                  kMasterKey.nDerivationMethod);
     kMasterKey.nDeriveIterations =
         2500000 / ((double)(GetTimeMillis() - nStartTime));
 
     nStartTime = GetTimeMillis();
     crypter.SetKeyFromPassphrase(strWalletPassphrase, kMasterKey.vchSalt,
                                  kMasterKey.nDeriveIterations,
                                  kMasterKey.nDerivationMethod);
     kMasterKey.nDeriveIterations =
         (kMasterKey.nDeriveIterations +
          kMasterKey.nDeriveIterations * 100 /
              ((double)(GetTimeMillis() - nStartTime))) /
         2;
 
     if (kMasterKey.nDeriveIterations < 25000) {
         kMasterKey.nDeriveIterations = 25000;
     }
 
     LogPrintf("Encrypting Wallet with an nDeriveIterations of %i\n",
               kMasterKey.nDeriveIterations);
 
     if (!crypter.SetKeyFromPassphrase(strWalletPassphrase, kMasterKey.vchSalt,
                                       kMasterKey.nDeriveIterations,
                                       kMasterKey.nDerivationMethod)) {
         return false;
     }
 
     if (!crypter.Encrypt(_vMasterKey, kMasterKey.vchCryptedKey)) {
         return false;
     }
 
     {
         LOCK(cs_wallet);
         mapMasterKeys[++nMasterKeyMaxID] = kMasterKey;
         assert(!pwalletdbEncryption);
         pwalletdbEncryption = new CWalletDB(*dbw);
         if (!pwalletdbEncryption->TxnBegin()) {
             delete pwalletdbEncryption;
             pwalletdbEncryption = nullptr;
             return false;
         }
         pwalletdbEncryption->WriteMasterKey(nMasterKeyMaxID, kMasterKey);
 
         if (!EncryptKeys(_vMasterKey)) {
             pwalletdbEncryption->TxnAbort();
             delete pwalletdbEncryption;
             // We now probably have half of our keys encrypted in memory, and
             // half not... die and let the user reload the unencrypted wallet.
             assert(false);
         }
 
         // Encryption was introduced in version 0.4.0
         SetMinVersion(FEATURE_WALLETCRYPT, pwalletdbEncryption, true);
 
         if (!pwalletdbEncryption->TxnCommit()) {
             delete pwalletdbEncryption;
             // We now have keys encrypted in memory, but not on disk... die to
             // avoid confusion and let the user reload the unencrypted wallet.
             assert(false);
         }
 
         delete pwalletdbEncryption;
         pwalletdbEncryption = nullptr;
 
         Lock();
         Unlock(strWalletPassphrase);
 
         // If we are using HD, replace the HD master key (seed) with a new one.
         if (IsHDEnabled()) {
             if (!SetHDMasterKey(GenerateNewHDMasterKey())) {
                 return false;
             }
         }
 
         NewKeyPool();
         Lock();
 
         // Need to completely rewrite the wallet file; if we don't, bdb might
         // keep bits of the unencrypted private key in slack space in the
         // database file.
         dbw->Rewrite();
     }
 
     NotifyStatusChanged(this);
     return true;
 }
 
 DBErrors CWallet::ReorderTransactions() {
     LOCK(cs_wallet);
     CWalletDB walletdb(*dbw);
 
     // Old wallets didn't have any defined order for transactions. Probably a
     // bad idea to change the output of this.
 
     // First: get all CWalletTx and CAccountingEntry into a sorted-by-time
     // multimap.
     TxItems txByTime;
 
     for (auto &entry : mapWallet) {
         CWalletTx *wtx = &entry.second;
         txByTime.insert(
             std::make_pair(wtx->nTimeReceived, TxPair(wtx, nullptr)));
     }
 
     std::list<CAccountingEntry> acentries;
     walletdb.ListAccountCreditDebit("", acentries);
     for (CAccountingEntry &entry : acentries) {
         txByTime.insert(std::make_pair(entry.nTime, TxPair(nullptr, &entry)));
     }
 
     nOrderPosNext = 0;
     std::vector<int64_t> nOrderPosOffsets;
     for (TxItems::iterator it = txByTime.begin(); it != txByTime.end(); ++it) {
         CWalletTx *const pwtx = (*it).second.first;
         CAccountingEntry *const pacentry = (*it).second.second;
         int64_t &nOrderPos =
             (pwtx != nullptr) ? pwtx->nOrderPos : pacentry->nOrderPos;
 
         if (nOrderPos == -1) {
             nOrderPos = nOrderPosNext++;
             nOrderPosOffsets.push_back(nOrderPos);
 
             if (pwtx) {
                 if (!walletdb.WriteTx(*pwtx)) {
                     return DBErrors::LOAD_FAIL;
                 }
             } else if (!walletdb.WriteAccountingEntry(pacentry->nEntryNo,
                                                       *pacentry)) {
                 return DBErrors::LOAD_FAIL;
             }
         } else {
             int64_t nOrderPosOff = 0;
             for (const int64_t &nOffsetStart : nOrderPosOffsets) {
                 if (nOrderPos >= nOffsetStart) {
                     ++nOrderPosOff;
                 }
             }
 
             nOrderPos += nOrderPosOff;
             nOrderPosNext = std::max(nOrderPosNext, nOrderPos + 1);
 
             if (!nOrderPosOff) {
                 continue;
             }
 
             // Since we're changing the order, write it back.
             if (pwtx) {
                 if (!walletdb.WriteTx(*pwtx)) {
                     return DBErrors::LOAD_FAIL;
                 }
             } else if (!walletdb.WriteAccountingEntry(pacentry->nEntryNo,
                                                       *pacentry)) {
                 return DBErrors::LOAD_FAIL;
             }
         }
     }
 
     walletdb.WriteOrderPosNext(nOrderPosNext);
 
     return DBErrors::LOAD_OK;
 }
 
 int64_t CWallet::IncOrderPosNext(CWalletDB *pwalletdb) {
     // nOrderPosNext
     AssertLockHeld(cs_wallet);
     int64_t nRet = nOrderPosNext++;
     if (pwalletdb) {
         pwalletdb->WriteOrderPosNext(nOrderPosNext);
     } else {
         CWalletDB(*dbw).WriteOrderPosNext(nOrderPosNext);
     }
 
     return nRet;
 }
 
 bool CWallet::AccountMove(std::string strFrom, std::string strTo,
                           const Amount nAmount, std::string strComment) {
     CWalletDB walletdb(*dbw);
     if (!walletdb.TxnBegin()) {
         return false;
     }
 
     int64_t nNow = GetAdjustedTime();
 
     // Debit
     CAccountingEntry debit;
     debit.nOrderPos = IncOrderPosNext(&walletdb);
     debit.strAccount = strFrom;
     debit.nCreditDebit = -nAmount;
     debit.nTime = nNow;
     debit.strOtherAccount = strTo;
     debit.strComment = strComment;
     AddAccountingEntry(debit, &walletdb);
 
     // Credit
     CAccountingEntry credit;
     credit.nOrderPos = IncOrderPosNext(&walletdb);
     credit.strAccount = strTo;
     credit.nCreditDebit = nAmount;
     credit.nTime = nNow;
     credit.strOtherAccount = strFrom;
     credit.strComment = strComment;
     AddAccountingEntry(credit, &walletdb);
 
     return walletdb.TxnCommit();
 }
 
 bool CWallet::GetLabelDestination(CTxDestination &dest,
                                   const std::string &label, bool bForceNew) {
     CWalletDB walletdb(*dbw);
 
     CAccount account;
     walletdb.ReadAccount(label, account);
 
     if (!bForceNew) {
         if (!account.vchPubKey.IsValid()) {
             bForceNew = true;
         } else {
             // Check if the current key has been used (TODO: check other
             // addresses with the same key)
             CScript scriptPubKey = GetScriptForDestination(
                 GetDestinationForKey(account.vchPubKey, g_address_type));
             for (std::map<TxId, CWalletTx>::iterator it = mapWallet.begin();
                  it != mapWallet.end() && account.vchPubKey.IsValid(); ++it) {
                 for (const CTxOut &txout : (*it).second.tx->vout) {
                     if (txout.scriptPubKey == scriptPubKey) {
                         bForceNew = true;
                         break;
                     }
                 }
             }
         }
     }
 
     // Generate a new key
     if (bForceNew) {
         if (!GetKeyFromPool(account.vchPubKey, false)) {
             return false;
         }
 
         LearnRelatedScripts(account.vchPubKey, g_address_type);
         dest = GetDestinationForKey(account.vchPubKey, g_address_type);
         SetAddressBook(dest, label, "receive");
         walletdb.WriteAccount(label, account);
     } else {
         dest = GetDestinationForKey(account.vchPubKey, g_address_type);
     }
 
     return true;
 }
 
 void CWallet::MarkDirty() {
     LOCK(cs_wallet);
     for (std::pair<const TxId, CWalletTx> &item : mapWallet) {
         item.second.MarkDirty();
     }
 }
 
 bool CWallet::AddToWallet(const CWalletTx &wtxIn, bool fFlushOnClose) {
     LOCK(cs_wallet);
 
     CWalletDB walletdb(*dbw, "r+", fFlushOnClose);
 
     const TxId &txid = wtxIn.GetId();
 
     // Inserts only if not already there, returns tx inserted or tx found.
     std::pair<std::map<TxId, CWalletTx>::iterator, bool> ret =
         mapWallet.insert(std::make_pair(txid, wtxIn));
     CWalletTx &wtx = (*ret.first).second;
     wtx.BindWallet(this);
     bool fInsertedNew = ret.second;
     if (fInsertedNew) {
         wtx.nTimeReceived = GetAdjustedTime();
         wtx.nOrderPos = IncOrderPosNext(&walletdb);
         wtxOrdered.insert(std::make_pair(wtx.nOrderPos, TxPair(&wtx, nullptr)));
         wtx.nTimeSmart = ComputeTimeSmart(wtx);
         AddToSpends(txid);
     }
 
     bool fUpdated = false;
     if (!fInsertedNew) {
         // Merge
         if (!wtxIn.hashUnset() && wtxIn.hashBlock != wtx.hashBlock) {
             wtx.hashBlock = wtxIn.hashBlock;
             fUpdated = true;
         }
 
         // If no longer abandoned, update
         if (wtxIn.hashBlock.IsNull() && wtx.isAbandoned()) {
             wtx.hashBlock = wtxIn.hashBlock;
             fUpdated = true;
         }
 
         if (wtxIn.nIndex != -1 && (wtxIn.nIndex != wtx.nIndex)) {
             wtx.nIndex = wtxIn.nIndex;
             fUpdated = true;
         }
 
         if (wtxIn.fFromMe && wtxIn.fFromMe != wtx.fFromMe) {
             wtx.fFromMe = wtxIn.fFromMe;
             fUpdated = true;
         }
     }
 
     //// debug print
     LogPrintf("AddToWallet %s  %s%s\n", wtxIn.GetId().ToString(),
               (fInsertedNew ? "new" : ""), (fUpdated ? "update" : ""));
 
     // Write to disk
     if ((fInsertedNew || fUpdated) && !walletdb.WriteTx(wtx)) {
         return false;
     }
 
     // Break debit/credit balance caches:
     wtx.MarkDirty();
 
     // Notify UI of new or updated transaction.
     NotifyTransactionChanged(this, txid, fInsertedNew ? CT_NEW : CT_UPDATED);
 
     // Notify an external script when a wallet transaction comes in or is
     // updated.
     std::string strCmd = gArgs.GetArg("-walletnotify", "");
 
     if (!strCmd.empty()) {
         boost::replace_all(strCmd, "%s", wtxIn.GetId().GetHex());
         std::thread t(runCommand, strCmd);
         // Thread runs free.
         t.detach();
     }
 
     return true;
 }
 
 bool CWallet::LoadToWallet(const CWalletTx &wtxIn) {
     const TxId &txid = wtxIn.GetId();
     CWalletTx &wtx = mapWallet.emplace(txid, wtxIn).first->second;
     wtx.BindWallet(this);
     wtxOrdered.insert(std::make_pair(wtx.nOrderPos, TxPair(&wtx, nullptr)));
     AddToSpends(txid);
     for (const CTxIn &txin : wtx.tx->vin) {
         auto it = mapWallet.find(txin.prevout.GetTxId());
         if (it != mapWallet.end()) {
             CWalletTx &prevtx = it->second;
             if (prevtx.nIndex == -1 && !prevtx.hashUnset()) {
                 MarkConflicted(prevtx.hashBlock, wtx.GetId());
             }
         }
     }
 
     return true;
 }
 
 /**
  * Add a transaction to the wallet, or update it.  pIndex and posInBlock should
  * be set when the transaction was known to be included in a block. When pIndex
  * == nullptr, then wallet state is not updated in AddToWallet, but
  * notifications happen and cached balances are marked dirty.
  *
  * If fUpdate is true, existing transactions will be updated.
  * TODO: One exception to this is that the abandoned state is cleared under the
  * assumption that any further notification of a transaction that was considered
  * abandoned is an indication that it is not safe to be considered abandoned.
  * Abandoned state should probably be more carefully tracked via different
  * posInBlock signals or by checking mempool presence when necessary.
  */
 bool CWallet::AddToWalletIfInvolvingMe(const CTransactionRef &ptx,
                                        const CBlockIndex *pIndex,
                                        int posInBlock, bool fUpdate) {
     const CTransaction &tx = *ptx;
     AssertLockHeld(cs_wallet);
 
     if (pIndex != nullptr) {
         for (const CTxIn &txin : tx.vin) {
             std::pair<TxSpends::const_iterator, TxSpends::const_iterator>
                 range = mapTxSpends.equal_range(txin.prevout);
             while (range.first != range.second) {
                 if (range.first->second != tx.GetId()) {
                     LogPrintf("Transaction %s (in block %s) conflicts with "
                               "wallet transaction %s (both spend %s:%i)\n",
                               tx.GetId().ToString(),
                               pIndex->GetBlockHash().ToString(),
                               range.first->second.ToString(),
                               range.first->first.GetTxId().ToString(),
                               range.first->first.GetN());
                     MarkConflicted(pIndex->GetBlockHash(), range.first->second);
                 }
                 range.first++;
             }
         }
     }
 
     bool fExisted = mapWallet.count(tx.GetId()) != 0;
     if (fExisted && !fUpdate) {
         return false;
     }
     if (fExisted || IsMine(tx) || IsFromMe(tx)) {
         /**
          * Check if any keys in the wallet keypool that were supposed to be
          * unused have appeared in a new transaction. If so, remove those keys
          * from the keypool. This can happen when restoring an old wallet backup
          * that does not contain the mostly recently created transactions from
          * newer versions of the wallet.
          */
 
         // loop though all outputs
         for (const CTxOut &txout : tx.vout) {
             // extract addresses and check if they match with an unused keypool
             // key
             std::vector<CKeyID> vAffected;
             CAffectedKeysVisitor(*this, vAffected).Process(txout.scriptPubKey);
             for (const CKeyID &keyid : vAffected) {
                 std::map<CKeyID, int64_t>::const_iterator mi =
                     m_pool_key_to_index.find(keyid);
                 if (mi != m_pool_key_to_index.end()) {
                     LogPrintf("%s: Detected a used keypool key, mark all "
                               "keypool key up to this key as used\n",
                               __func__);
                     MarkReserveKeysAsUsed(mi->second);
 
                     if (!TopUpKeyPool()) {
                         LogPrintf(
                             "%s: Topping up keypool failed (locked wallet)\n",
                             __func__);
                     }
                 }
             }
         }
 
         CWalletTx wtx(this, ptx);
 
         // Get merkle branch if transaction was found in a block
         if (pIndex != nullptr) {
             wtx.SetMerkleBranch(pIndex, posInBlock);
         }
 
         return AddToWallet(wtx, false);
     }
 
     return false;
 }
 
 bool CWallet::TransactionCanBeAbandoned(const TxId &txid) const {
     LOCK2(cs_main, cs_wallet);
     const CWalletTx *wtx = GetWalletTx(txid);
     return wtx && !wtx->isAbandoned() && wtx->GetDepthInMainChain() <= 0 &&
            !wtx->InMempool();
 }
 
 bool CWallet::AbandonTransaction(const TxId &txid) {
     LOCK2(cs_main, cs_wallet);
 
     CWalletDB walletdb(*dbw, "r+");
 
     std::set<TxId> todo;
     std::set<TxId> done;
 
     // Can't mark abandoned if confirmed or in mempool
     auto it = mapWallet.find(txid);
     assert(it != mapWallet.end());
     CWalletTx &origtx = it->second;
     if (origtx.GetDepthInMainChain() > 0 || origtx.InMempool()) {
         return false;
     }
 
     todo.insert(txid);
 
     while (!todo.empty()) {
         const TxId now = *todo.begin();
         todo.erase(now);
         done.insert(now);
         it = mapWallet.find(now);
         assert(it != mapWallet.end());
         CWalletTx &wtx = it->second;
         int currentconfirm = wtx.GetDepthInMainChain();
         // If the orig tx was not in block, none of its spends can be.
         assert(currentconfirm <= 0);
         // If (currentconfirm < 0) {Tx and spends are already conflicted, no
         // need to abandon}
         if (currentconfirm == 0 && !wtx.isAbandoned()) {
             // If the orig tx was not in block/mempool, none of its spends can
             // be in mempool.
             assert(!wtx.InMempool());
             wtx.nIndex = -1;
             wtx.setAbandoned();
             wtx.MarkDirty();
             walletdb.WriteTx(wtx);
             NotifyTransactionChanged(this, wtx.GetId(), CT_UPDATED);
             // Iterate over all its outputs, and mark transactions in the wallet
             // that spend them abandoned too.
             TxSpends::const_iterator iter =
                 mapTxSpends.lower_bound(COutPoint(now, 0));
             while (iter != mapTxSpends.end() && iter->first.GetTxId() == now) {
                 if (!done.count(iter->second)) {
                     todo.insert(iter->second);
                 }
                 iter++;
             }
 
             // If a transaction changes 'conflicted' state, that changes the
             // balance available of the outputs it spends. So force those to be
             // recomputed.
             for (const CTxIn &txin : wtx.tx->vin) {
                 auto it2 = mapWallet.find(txin.prevout.GetTxId());
                 if (it2 != mapWallet.end()) {
                     it2->second.MarkDirty();
                 }
             }
         }
     }
 
     return true;
 }
 
 void CWallet::MarkConflicted(const uint256 &hashBlock, const TxId &txid) {
     LOCK2(cs_main, cs_wallet);
 
     int conflictconfirms = 0;
     CBlockIndex *pindex = LookupBlockIndex(hashBlock);
     if (pindex && chainActive.Contains(pindex)) {
         conflictconfirms = -(chainActive.Height() - pindex->nHeight + 1);
     }
 
     // If number of conflict confirms cannot be determined, this means that the
     // block is still unknown or not yet part of the main chain, for example
     // when loading the wallet during a reindex. Do nothing in that case.
     if (conflictconfirms >= 0) {
         return;
     }
 
     // Do not flush the wallet here for performance reasons.
     CWalletDB walletdb(*dbw, "r+", false);
 
     std::set<TxId> todo;
     std::set<TxId> done;
 
     todo.insert(txid);
 
     while (!todo.empty()) {
         const TxId now = *todo.begin();
         todo.erase(now);
         done.insert(now);
         auto it = mapWallet.find(now);
         assert(it != mapWallet.end());
         CWalletTx &wtx = it->second;
         int currentconfirm = wtx.GetDepthInMainChain();
         if (conflictconfirms < currentconfirm) {
             // Block is 'more conflicted' than current confirm; update.
             // Mark transaction as conflicted with this block.
             wtx.nIndex = -1;
             wtx.hashBlock = hashBlock;
             wtx.MarkDirty();
             walletdb.WriteTx(wtx);
             // Iterate over all its outputs, and mark transactions in the wallet
             // that spend them conflicted too.
             TxSpends::const_iterator iter =
                 mapTxSpends.lower_bound(COutPoint(now, 0));
             while (iter != mapTxSpends.end() && iter->first.GetTxId() == now) {
                 if (!done.count(iter->second)) {
                     todo.insert(iter->second);
                 }
                 iter++;
             }
 
             // If a transaction changes 'conflicted' state, that changes the
             // balance available of the outputs it spends. So force those to be
             // recomputed.
             for (const CTxIn &txin : wtx.tx->vin) {
                 auto it2 = mapWallet.find(txin.prevout.GetTxId());
                 if (it2 != mapWallet.end()) {
                     it2->second.MarkDirty();
                 }
             }
         }
     }
 }
 
 void CWallet::SyncTransaction(const CTransactionRef &ptx,
                               const CBlockIndex *pindex, int posInBlock) {
     const CTransaction &tx = *ptx;
 
     if (!AddToWalletIfInvolvingMe(ptx, pindex, posInBlock, true)) {
         // Not one of ours
         return;
     }
 
     // If a transaction changes 'conflicted' state, that changes the balance
     // available of the outputs it spends. So force those to be
     // recomputed, also:
     for (const CTxIn &txin : tx.vin) {
         auto it = mapWallet.find(txin.prevout.GetTxId());
         if (it != mapWallet.end()) {
             it->second.MarkDirty();
         }
     }
 }
 
 void CWallet::TransactionAddedToMempool(const CTransactionRef &ptx) {
     LOCK2(cs_main, cs_wallet);
     SyncTransaction(ptx);
 
     auto it = mapWallet.find(ptx->GetId());
     if (it != mapWallet.end()) {
         it->second.fInMempool = true;
     }
 }
 
 void CWallet::TransactionRemovedFromMempool(const CTransactionRef &ptx) {
     LOCK(cs_wallet);
     auto it = mapWallet.find(ptx->GetId());
     if (it != mapWallet.end()) {
         it->second.fInMempool = false;
     }
 }
 
 void CWallet::BlockConnected(
     const std::shared_ptr<const CBlock> &pblock, const CBlockIndex *pindex,
     const std::vector<CTransactionRef> &vtxConflicted) {
     LOCK2(cs_main, cs_wallet);
 
     // TODO: Temporarily ensure that mempool removals are notified before
     // connected transactions. This shouldn't matter, but the abandoned state of
     // transactions in our wallet is currently cleared when we receive another
     // notification and there is a race condition where notification of a
     // connected conflict might cause an outside process to abandon a
     // transaction and then have it inadvertently cleared by the notification
     // that the conflicted transaction was evicted.
     for (const CTransactionRef &ptx : vtxConflicted) {
         SyncTransaction(ptx);
         TransactionRemovedFromMempool(ptx);
     }
 
     for (size_t i = 0; i < pblock->vtx.size(); i++) {
         SyncTransaction(pblock->vtx[i], pindex, i);
         TransactionRemovedFromMempool(pblock->vtx[i]);
     }
 
     m_last_block_processed = pindex;
 }
 
 void CWallet::BlockDisconnected(const std::shared_ptr<const CBlock> &pblock) {
     LOCK2(cs_main, cs_wallet);
 
     for (const CTransactionRef &ptx : pblock->vtx) {
         SyncTransaction(ptx);
     }
 }
 
 void CWallet::BlockUntilSyncedToCurrentChain() {
     AssertLockNotHeld(cs_main);
     AssertLockNotHeld(cs_wallet);
 
     {
         // Skip the queue-draining stuff if we know we're caught up with
         // chainActive.Tip()...
         // We could also take cs_wallet here, and call m_last_block_processed
         // protected by cs_wallet instead of cs_main, but as long as we need
         // cs_main here anyway, its easier to just call it cs_main-protected.
         LOCK(cs_main);
         const CBlockIndex *initialChainTip = chainActive.Tip();
 
         if (m_last_block_processed->GetAncestor(initialChainTip->nHeight) ==
             initialChainTip) {
             return;
         }
     }
 
     // ...otherwise put a callback in the validation interface queue and wait
     // for the queue to drain enough to execute it (indicating we are caught up
     // at least with the time we entered this function).
     SyncWithValidationInterfaceQueue();
 }
 
 isminetype CWallet::IsMine(const CTxIn &txin) const {
     LOCK(cs_wallet);
     std::map<TxId, CWalletTx>::const_iterator mi =
         mapWallet.find(txin.prevout.GetTxId());
     if (mi != mapWallet.end()) {
         const CWalletTx &prev = (*mi).second;
         if (txin.prevout.GetN() < prev.tx->vout.size()) {
             return IsMine(prev.tx->vout[txin.prevout.GetN()]);
         }
     }
 
     return ISMINE_NO;
 }
 
 // Note that this function doesn't distinguish between a 0-valued input, and a
 // not-"is mine" (according to the filter) input.
 Amount CWallet::GetDebit(const CTxIn &txin, const isminefilter &filter) const {
     LOCK(cs_wallet);
     std::map<TxId, CWalletTx>::const_iterator mi =
         mapWallet.find(txin.prevout.GetTxId());
     if (mi != mapWallet.end()) {
         const CWalletTx &prev = (*mi).second;
         if (txin.prevout.GetN() < prev.tx->vout.size()) {
             if (IsMine(prev.tx->vout[txin.prevout.GetN()]) & filter) {
                 return prev.tx->vout[txin.prevout.GetN()].nValue;
             }
         }
     }
 
     return Amount::zero();
 }
 
 isminetype CWallet::IsMine(const CTxOut &txout) const {
     return ::IsMine(*this, txout.scriptPubKey);
 }
 
 Amount CWallet::GetCredit(const CTxOut &txout,
                           const isminefilter &filter) const {
     if (!MoneyRange(txout.nValue)) {
         throw std::runtime_error(std::string(__func__) +
                                  ": value out of range");
     }
 
     return (IsMine(txout) & filter) ? txout.nValue : Amount::zero();
 }
 
 bool CWallet::IsChange(const CTxOut &txout) const {
     // TODO: fix handling of 'change' outputs. The assumption is that any
     // payment to a script that is ours, but is not in the address book is
     // change. That assumption is likely to break when we implement
     // multisignature wallets that return change back into a
     // multi-signature-protected address; a better way of identifying which
     // outputs are 'the send' and which are 'the change' will need to be
     // implemented (maybe extend CWalletTx to remember which output, if any, was
     // change).
     if (::IsMine(*this, txout.scriptPubKey)) {
         CTxDestination address;
         if (!ExtractDestination(txout.scriptPubKey, address)) {
             return true;
         }
 
         LOCK(cs_wallet);
         if (!mapAddressBook.count(address)) {
             return true;
         }
     }
 
     return false;
 }
 
 Amount CWallet::GetChange(const CTxOut &txout) const {
     if (!MoneyRange(txout.nValue)) {
         throw std::runtime_error(std::string(__func__) +
                                  ": value out of range");
     }
 
     return (IsChange(txout) ? txout.nValue : Amount::zero());
 }
 
 bool CWallet::IsMine(const CTransaction &tx) const {
     for (const CTxOut &txout : tx.vout) {
         if (IsMine(txout)) {
             return true;
         }
     }
 
     return false;
 }
 
 bool CWallet::IsFromMe(const CTransaction &tx) const {
     return GetDebit(tx, ISMINE_ALL) > Amount::zero();
 }
 
 Amount CWallet::GetDebit(const CTransaction &tx,
                          const isminefilter &filter) const {
     Amount nDebit = Amount::zero();
     for (const CTxIn &txin : tx.vin) {
         nDebit += GetDebit(txin, filter);
         if (!MoneyRange(nDebit)) {
             throw std::runtime_error(std::string(__func__) +
                                      ": value out of range");
         }
     }
 
     return nDebit;
 }
 
 bool CWallet::IsAllFromMe(const CTransaction &tx,
                           const isminefilter &filter) const {
     LOCK(cs_wallet);
 
     for (const CTxIn &txin : tx.vin) {
         auto mi = mapWallet.find(txin.prevout.GetTxId());
         if (mi == mapWallet.end()) {
             // Any unknown inputs can't be from us.
             return false;
         }
 
         const CWalletTx &prev = (*mi).second;
 
         if (txin.prevout.GetN() >= prev.tx->vout.size()) {
             // Invalid input!
             return false;
         }
 
         if (!(IsMine(prev.tx->vout[txin.prevout.GetN()]) & filter)) {
             return false;
         }
     }
 
     return true;
 }
 
 Amount CWallet::GetCredit(const CTransaction &tx,
                           const isminefilter &filter) const {
     Amount nCredit = Amount::zero();
     for (const CTxOut &txout : tx.vout) {
         nCredit += GetCredit(txout, filter);
         if (!MoneyRange(nCredit)) {
             throw std::runtime_error(std::string(__func__) +
                                      ": value out of range");
         }
     }
 
     return nCredit;
 }
 
 Amount CWallet::GetChange(const CTransaction &tx) const {
     Amount nChange = Amount::zero();
     for (const CTxOut &txout : tx.vout) {
         nChange += GetChange(txout);
         if (!MoneyRange(nChange)) {
             throw std::runtime_error(std::string(__func__) +
                                      ": value out of range");
         }
     }
 
     return nChange;
 }
 
 CPubKey CWallet::GenerateNewHDMasterKey() {
     CKey key;
     key.MakeNewKey(true);
 
     int64_t nCreationTime = GetTime();
     CKeyMetadata metadata(nCreationTime);
 
     // Calculate the pubkey.
     CPubKey pubkey = key.GetPubKey();
     assert(key.VerifyPubKey(pubkey));
 
     // Set the hd keypath to "m" -> Master, refers the masterkeyid to itself.
     metadata.hdKeypath = "m";
     metadata.hdMasterKeyID = pubkey.GetID();
 
     LOCK(cs_wallet);
 
     // mem store the metadata
     mapKeyMetadata[pubkey.GetID()] = metadata;
 
     // Write the key&metadata to the database.
     if (!AddKeyPubKey(key, pubkey)) {
         throw std::runtime_error(std::string(__func__) +
                                  ": AddKeyPubKey failed");
     }
 
     return pubkey;
 }
 
 bool CWallet::SetHDMasterKey(const CPubKey &pubkey) {
     LOCK(cs_wallet);
 
     // Store the keyid (hash160) together with the child index counter in the
     // database as a hdchain object.
     CHDChain newHdChain;
     newHdChain.nVersion = CanSupportFeature(FEATURE_HD_SPLIT)
                               ? CHDChain::VERSION_HD_CHAIN_SPLIT
                               : CHDChain::VERSION_HD_BASE;
     newHdChain.masterKeyID = pubkey.GetID();
     SetHDChain(newHdChain, false);
 
     return true;
 }
 
 bool CWallet::SetHDChain(const CHDChain &chain, bool memonly) {
     LOCK(cs_wallet);
     if (!memonly && !CWalletDB(*dbw).WriteHDChain(chain)) {
         throw std::runtime_error(std::string(__func__) +
                                  ": writing chain failed");
     }
 
     hdChain = chain;
     return true;
 }
 
 bool CWallet::IsHDEnabled() const {
     return !hdChain.masterKeyID.IsNull();
 }
 
 int64_t CWalletTx::GetTxTime() const {
     int64_t n = nTimeSmart;
     return n ? n : nTimeReceived;
 }
 
 int CWalletTx::GetRequestCount() const {
     LOCK(pwallet->cs_wallet);
 
     // Returns -1 if it wasn't being tracked.
     int nRequests = -1;
 
     if (IsCoinBase()) {
         // Generated block.
         if (!hashUnset()) {
             std::map<uint256, int>::const_iterator mi =
                 pwallet->mapRequestCount.find(hashBlock);
             if (mi != pwallet->mapRequestCount.end()) {
                 nRequests = (*mi).second;
             }
         }
     } else {
         // Did anyone request this transaction?
         std::map<uint256, int>::const_iterator mi =
             pwallet->mapRequestCount.find(GetId());
         if (mi != pwallet->mapRequestCount.end()) {
             nRequests = (*mi).second;
 
             // How about the block it's in?
             if (nRequests == 0 && !hashUnset()) {
                 std::map<uint256, int>::const_iterator _mi =
                     pwallet->mapRequestCount.find(hashBlock);
                 if (_mi != pwallet->mapRequestCount.end()) {
                     nRequests = (*_mi).second;
                 } else {
                     // If it's in someone else's block it must have got out.
                     nRequests = 1;
                 }
             }
         }
     }
 
     return nRequests;
 }
 
 void CWalletTx::GetAmounts(std::list<COutputEntry> &listReceived,
                            std::list<COutputEntry> &listSent, Amount &nFee,
                            std::string &strSentAccount,
                            const isminefilter &filter) const {
     nFee = Amount::zero();
     listReceived.clear();
     listSent.clear();
     strSentAccount = strFromAccount;
 
     // Compute fee:
     Amount nDebit = GetDebit(filter);
     // debit>0 means we signed/sent this transaction.
     if (nDebit > Amount::zero()) {
         Amount nValueOut = tx->GetValueOut();
         nFee = (nDebit - nValueOut);
     }
 
     // Sent/received.
     for (unsigned int i = 0; i < tx->vout.size(); ++i) {
         const CTxOut &txout = tx->vout[i];
         isminetype fIsMine = pwallet->IsMine(txout);
         // Only need to handle txouts if AT LEAST one of these is true:
         //   1) they debit from us (sent)
         //   2) the output is to us (received)
         if (nDebit > Amount::zero()) {
             // Don't report 'change' txouts
             if (pwallet->IsChange(txout)) {
                 continue;
             }
         } else if (!(fIsMine & filter)) {
             continue;
         }
 
         // In either case, we need to get the destination address.
         CTxDestination address;
 
         if (!ExtractDestination(txout.scriptPubKey, address) &&
             !txout.scriptPubKey.IsUnspendable()) {
             LogPrintf("CWalletTx::GetAmounts: Unknown transaction type found, "
                       "txid %s\n",
                       this->GetId().ToString());
             address = CNoDestination();
         }
 
         COutputEntry output = {address, txout.nValue, (int)i};
 
         // If we are debited by the transaction, add the output as a "sent"
         // entry.
         if (nDebit > Amount::zero()) {
             listSent.push_back(output);
         }
 
         // If we are receiving the output, add it as a "received" entry.
         if (fIsMine & filter) {
             listReceived.push_back(output);
         }
     }
 }
 
 /**
  * Scan active chain for relevant transactions after importing keys. This should
  * be called whenever new keys are added to the wallet, with the oldest key
  * creation time.
  *
  * @return Earliest timestamp that could be successfully scanned from. Timestamp
  * returned will be higher than startTime if relevant blocks could not be read.
  */
 int64_t CWallet::RescanFromTime(int64_t startTime,
                                 const WalletRescanReserver &reserver,
                                 bool update) {
     // Find starting block. May be null if nCreateTime is greater than the
     // highest blockchain timestamp, in which case there is nothing that needs
     // to be scanned.
     CBlockIndex *startBlock = nullptr;
     {
         LOCK(cs_main);
         startBlock =
             chainActive.FindEarliestAtLeast(startTime - TIMESTAMP_WINDOW);
         LogPrintf("%s: Rescanning last %i blocks\n", __func__,
                   startBlock ? chainActive.Height() - startBlock->nHeight + 1
                              : 0);
     }
 
     if (startBlock) {
         const CBlockIndex *const failedBlock =
             ScanForWalletTransactions(startBlock, nullptr, reserver, update);
         if (failedBlock) {
             return failedBlock->GetBlockTimeMax() + TIMESTAMP_WINDOW + 1;
         }
     }
     return startTime;
 }
 
 /**
  * Scan the block chain (starting in pindexStart) for transactions from or to
  * us. If fUpdate is true, found transactions that already exist in the wallet
  * will be updated.
  *
  * Returns null if scan was successful. Otherwise, if a complete rescan was not
  * possible (due to pruning or corruption), returns pointer to the most recent
  * block that could not be scanned.
  *
  * If pindexStop is not a nullptr, the scan will stop at the block-index
  * defined by pindexStop
  *
  * Caller needs to make sure pindexStop (and the optional pindexStart) are on
  * the main chain after to the addition of any new keys you want to detect
  * transactions for.
  */
 CBlockIndex *CWallet::ScanForWalletTransactions(
     CBlockIndex *pindexStart, CBlockIndex *pindexStop,
     const WalletRescanReserver &reserver, bool fUpdate) {
     int64_t nNow = GetTime();
 
     assert(reserver.isReserved());
     if (pindexStop) {
         assert(pindexStop->nHeight >= pindexStart->nHeight);
     }
 
     CBlockIndex *pindex = pindexStart;
     CBlockIndex *ret = nullptr;
     {
         fAbortRescan = false;
 
         // Show rescan progress in GUI as dialog or on splashscreen, if -rescan
         // on startup.
         ShowProgress(_("Rescanning..."), 0);
         CBlockIndex *tip = nullptr;
         double dProgressStart;
         double dProgressTip;
         {
             LOCK(cs_main);
             tip = chainActive.Tip();
             dProgressStart =
                 GuessVerificationProgress(chainParams.TxData(), pindex);
             dProgressTip = GuessVerificationProgress(chainParams.TxData(), tip);
         }
         while (pindex && !fAbortRescan) {
             if (pindex->nHeight % 100 == 0 &&
                 dProgressTip - dProgressStart > 0.0) {
                 double gvp = 0;
                 {
                     LOCK(cs_main);
                     gvp =
                         GuessVerificationProgress(chainParams.TxData(), pindex);
                 }
                 ShowProgress(
                     _("Rescanning..."),
                     std::max(
                         1, std::min(99, (int)((gvp - dProgressStart) /
                                               (dProgressTip - dProgressStart) *
                                               100))));
             }
             if (GetTime() >= nNow + 60) {
                 nNow = GetTime();
                 LOCK(cs_main);
                 LogPrintf(
                     "Still rescanning. At block %d. Progress=%f\n",
                     pindex->nHeight,
                     GuessVerificationProgress(chainParams.TxData(), pindex));
             }
 
             CBlock block;
             if (ReadBlockFromDisk(block, pindex, GetConfig())) {
                 LOCK2(cs_main, cs_wallet);
                 if (pindex && !chainActive.Contains(pindex)) {
                     // Abort scan if current block is no longer active, to
                     // prevent marking transactions as coming from the wrong
                     // block.
                     ret = pindex;
                     break;
                 }
                 for (size_t posInBlock = 0; posInBlock < block.vtx.size();
                      ++posInBlock) {
                     AddToWalletIfInvolvingMe(block.vtx[posInBlock], pindex,
                                              posInBlock, fUpdate);
                 }
             } else {
                 ret = pindex;
             }
             if (pindex == pindexStop) {
                 break;
             }
             {
                 LOCK(cs_main);
                 pindex = chainActive.Next(pindex);
                 if (tip != chainActive.Tip()) {
                     tip = chainActive.Tip();
                     // in case the tip has changed, update progress max
                     dProgressTip =
                         GuessVerificationProgress(chainParams.TxData(), tip);
                 }
             }
         }
 
         if (pindex && fAbortRescan) {
             LogPrintf("Rescan aborted at block %d. Progress=%f\n",
                       pindex->nHeight,
                       GuessVerificationProgress(chainParams.TxData(), pindex));
         }
 
         // Hide progress dialog in GUI.
         ShowProgress(_("Rescanning..."), 100);
     }
     return ret;
 }
 
 void CWallet::ReacceptWalletTransactions() {
     // If transactions aren't being broadcasted, don't let them into local
     // mempool either.
     if (!fBroadcastTransactions) {
         return;
     }
 
     LOCK2(cs_main, cs_wallet);
     std::map<int64_t, CWalletTx *> mapSorted;
 
     // Sort pending wallet transactions based on their initial wallet insertion
     // order.
     for (std::pair<const TxId, CWalletTx> &item : mapWallet) {
         const TxId &wtxid = item.first;
         CWalletTx &wtx = item.second;
         assert(wtx.GetId() == wtxid);
 
         int nDepth = wtx.GetDepthInMainChain();
 
         if (!wtx.IsCoinBase() && (nDepth == 0 && !wtx.isAbandoned())) {
             mapSorted.insert(std::make_pair(wtx.nOrderPos, &wtx));
         }
     }
 
     // Try to add wallet transactions to memory pool.
     for (std::pair<const int64_t, CWalletTx *> &item : mapSorted) {
         CWalletTx &wtx = *(item.second);
 
         LOCK(g_mempool.cs);
         CValidationState state;
         wtx.AcceptToMemoryPool(maxTxFee, state);
     }
 }
 
 bool CWalletTx::RelayWalletTransaction(CConnman *connman) {
     assert(pwallet->GetBroadcastTransactions());
     if (IsCoinBase() || isAbandoned() || GetDepthInMainChain() != 0) {
         return false;
     }
 
     CValidationState state;
     // GetDepthInMainChain already catches known conflicts.
     if (InMempool() || AcceptToMemoryPool(maxTxFee, state)) {
         LogPrintf("Relaying wtx %s\n", GetId().ToString());
         if (connman) {
             CInv inv(MSG_TX, GetId());
             connman->ForEachNode(
                 [&inv](CNode *pnode) { pnode->PushInventory(inv); });
             return true;
         }
     }
 
     return false;
 }
 
 std::set<TxId> CWalletTx::GetConflicts() const {
     std::set<TxId> result;
     if (pwallet != nullptr) {
         const TxId &txid = GetId();
         result = pwallet->GetConflicts(txid);
         result.erase(txid);
     }
 
     return result;
 }
 
 Amount CWalletTx::GetDebit(const isminefilter &filter) const {
     if (tx->vin.empty()) {
         return Amount::zero();
     }
 
     Amount debit = Amount::zero();
     if (filter & ISMINE_SPENDABLE) {
         if (fDebitCached) {
             debit += nDebitCached;
         } else {
             nDebitCached = pwallet->GetDebit(*tx, ISMINE_SPENDABLE);
             fDebitCached = true;
             debit += nDebitCached;
         }
     }
 
     if (filter & ISMINE_WATCH_ONLY) {
         if (fWatchDebitCached) {
             debit += nWatchDebitCached;
         } else {
             nWatchDebitCached = pwallet->GetDebit(*tx, ISMINE_WATCH_ONLY);
             fWatchDebitCached = true;
             debit += Amount(nWatchDebitCached);
         }
     }
 
     return debit;
 }
 
 Amount CWalletTx::GetCredit(const isminefilter &filter) const {
     // Must wait until coinbase is safely deep enough in the chain before
     // valuing it.
     if (IsImmatureCoinBase()) {
         return Amount::zero();
     }
 
     Amount credit = Amount::zero();
     if (filter & ISMINE_SPENDABLE) {
         // GetBalance can assume transactions in mapWallet won't change.
         if (fCreditCached) {
             credit += nCreditCached;
         } else {
             nCreditCached = pwallet->GetCredit(*tx, ISMINE_SPENDABLE);
             fCreditCached = true;
             credit += nCreditCached;
         }
     }
 
     if (filter & ISMINE_WATCH_ONLY) {
         if (fWatchCreditCached) {
             credit += nWatchCreditCached;
         } else {
             nWatchCreditCached = pwallet->GetCredit(*tx, ISMINE_WATCH_ONLY);
             fWatchCreditCached = true;
             credit += nWatchCreditCached;
         }
     }
 
     return credit;
 }
 
 Amount CWalletTx::GetImmatureCredit(bool fUseCache) const {
     if (IsImmatureCoinBase() && IsInMainChain()) {
         if (fUseCache && fImmatureCreditCached) {
             return nImmatureCreditCached;
         }
 
         nImmatureCreditCached = pwallet->GetCredit(*tx, ISMINE_SPENDABLE);
         fImmatureCreditCached = true;
         return nImmatureCreditCached;
     }
 
     return Amount::zero();
 }
 
 Amount CWalletTx::GetAvailableCredit(bool fUseCache) const {
     if (pwallet == nullptr) {
         return Amount::zero();
     }
 
     // Must wait until coinbase is safely deep enough in the chain before
     // valuing it.
     if (IsImmatureCoinBase()) {
         return Amount::zero();
     }
 
     if (fUseCache && fAvailableCreditCached) {
         return nAvailableCreditCached;
     }
 
     Amount nCredit = Amount::zero();
     for (uint32_t i = 0; i < tx->vout.size(); i++) {
         if (!pwallet->IsSpent(GetId(), i)) {
             const CTxOut &txout = tx->vout[i];
             nCredit += pwallet->GetCredit(txout, ISMINE_SPENDABLE);
             if (!MoneyRange(nCredit)) {
                 throw std::runtime_error(
                     "CWalletTx::GetAvailableCredit() : value out of range");
             }
         }
     }
 
     nAvailableCreditCached = nCredit;
     fAvailableCreditCached = true;
     return nCredit;
 }
 
 Amount CWalletTx::GetImmatureWatchOnlyCredit(const bool fUseCache) const {
     if (IsImmatureCoinBase() && IsInMainChain()) {
         if (fUseCache && fImmatureWatchCreditCached) {
             return nImmatureWatchCreditCached;
         }
 
         nImmatureWatchCreditCached = pwallet->GetCredit(*tx, ISMINE_WATCH_ONLY);
         fImmatureWatchCreditCached = true;
         return nImmatureWatchCreditCached;
     }
 
     return Amount::zero();
 }
 
 Amount CWalletTx::GetAvailableWatchOnlyCredit(const bool fUseCache) const {
     if (pwallet == nullptr) {
         return Amount::zero();
     }
 
     // Must wait until coinbase is safely deep enough in the chain before
     // valuing it.
     if (IsCoinBase() && GetBlocksToMaturity() > 0) {
         return Amount::zero();
     }
 
     if (fUseCache && fAvailableWatchCreditCached) {
         return nAvailableWatchCreditCached;
     }
 
     Amount nCredit = Amount::zero();
     for (uint32_t i = 0; i < tx->vout.size(); i++) {
         if (!pwallet->IsSpent(GetId(), i)) {
             const CTxOut &txout = tx->vout[i];
             nCredit += pwallet->GetCredit(txout, ISMINE_WATCH_ONLY);
             if (!MoneyRange(nCredit)) {
                 throw std::runtime_error(
                     "CWalletTx::GetAvailableCredit() : value out of range");
             }
         }
     }
 
     nAvailableWatchCreditCached = nCredit;
     fAvailableWatchCreditCached = true;
     return nCredit;
 }
 
 Amount CWalletTx::GetChange() const {
     if (fChangeCached) {
         return nChangeCached;
     }
 
     nChangeCached = pwallet->GetChange(*tx);
     fChangeCached = true;
     return nChangeCached;
 }
 
 bool CWalletTx::InMempool() const {
     return fInMempool;
 }
 
 bool CWalletTx::IsTrusted() const {
     // Quick answer in most cases
     if (!CheckFinalTx(*tx)) {
         return false;
     }
 
     int nDepth = GetDepthInMainChain();
     if (nDepth >= 1) {
         return true;
     }
 
     if (nDepth < 0) {
         return false;
     }
 
     // using wtx's cached debit
     if (!bSpendZeroConfChange || !IsFromMe(ISMINE_ALL)) {
         return false;
     }
 
     // Don't trust unconfirmed transactions from us unless they are in the
     // mempool.
     if (!InMempool()) {
         return false;
     }
 
     // Trusted if all inputs are from us and are in the mempool:
     for (const CTxIn &txin : tx->vin) {
         // Transactions not sent by us: not trusted
         const CWalletTx *parent = pwallet->GetWalletTx(txin.prevout.GetTxId());
         if (parent == nullptr) {
             return false;
         }
 
         const CTxOut &parentOut = parent->tx->vout[txin.prevout.GetN()];
         if (pwallet->IsMine(parentOut) != ISMINE_SPENDABLE) {
             return false;
         }
     }
 
     return true;
 }
 
 bool CWalletTx::IsEquivalentTo(const CWalletTx &_tx) const {
     CMutableTransaction tx1 = *this->tx;
     CMutableTransaction tx2 = *_tx.tx;
     for (CTxIn &in : tx1.vin) {
         in.scriptSig = CScript();
     }
 
     for (CTxIn &in : tx2.vin) {
         in.scriptSig = CScript();
     }
 
     return CTransaction(tx1) == CTransaction(tx2);
 }
 
 std::vector<uint256>
 CWallet::ResendWalletTransactionsBefore(int64_t nTime, CConnman *connman) {
     std::vector<uint256> result;
 
     LOCK(cs_wallet);
 
     // Sort them in chronological order
     std::multimap<unsigned int, CWalletTx *> mapSorted;
     for (std::pair<const TxId, CWalletTx> &item : mapWallet) {
         CWalletTx &wtx = item.second;
         // Don't rebroadcast if newer than nTime:
         if (wtx.nTimeReceived > nTime) {
             continue;
         }
 
         mapSorted.insert(std::make_pair(wtx.nTimeReceived, &wtx));
     }
 
     for (std::pair<const unsigned int, CWalletTx *> &item : mapSorted) {
         CWalletTx &wtx = *item.second;
         if (wtx.RelayWalletTransaction(connman)) {
             result.push_back(wtx.GetId());
         }
     }
 
     return result;
 }
 
 void CWallet::ResendWalletTransactions(int64_t nBestBlockTime,
                                        CConnman *connman) {
     // Do this infrequently and randomly to avoid giving away that these are our
     // transactions.
     if (GetTime() < nNextResend || !fBroadcastTransactions) {
         return;
     }
 
     bool fFirst = (nNextResend == 0);
     nNextResend = GetTime() + GetRand(30 * 60);
     if (fFirst) {
         return;
     }
 
     // Only do it if there's been a new block since last time
     if (nBestBlockTime < nLastResend) {
         return;
     }
 
     nLastResend = GetTime();
 
     // Rebroadcast unconfirmed txes older than 5 minutes before the last block
     // was found:
     std::vector<uint256> relayed =
         ResendWalletTransactionsBefore(nBestBlockTime - 5 * 60, connman);
     if (!relayed.empty()) {
         LogPrintf("%s: rebroadcast %u unconfirmed transactions\n", __func__,
                   relayed.size());
     }
 }
 
 /** @} */ // end of mapWallet
 
 /**
  * @defgroup Actions
  *
  * @{
  */
 Amount CWallet::GetBalance() const {
     LOCK2(cs_main, cs_wallet);
 
     Amount nTotal = Amount::zero();
     for (const auto &entry : mapWallet) {
         const CWalletTx *pcoin = &entry.second;
         if (pcoin->IsTrusted()) {
             nTotal += pcoin->GetAvailableCredit();
         }
     }
 
     return nTotal;
 }
 
 Amount CWallet::GetUnconfirmedBalance() const {
     LOCK2(cs_main, cs_wallet);
 
     Amount nTotal = Amount::zero();
     for (const auto &entry : mapWallet) {
         const CWalletTx *pcoin = &entry.second;
         if (!pcoin->IsTrusted() && pcoin->GetDepthInMainChain() == 0 &&
             pcoin->InMempool()) {
             nTotal += pcoin->GetAvailableCredit();
         }
     }
 
     return nTotal;
 }
 
 Amount CWallet::GetImmatureBalance() const {
     LOCK2(cs_main, cs_wallet);
 
     Amount nTotal = Amount::zero();
     for (const auto &entry : mapWallet) {
         const CWalletTx *pcoin = &entry.second;
         nTotal += pcoin->GetImmatureCredit();
     }
 
     return nTotal;
 }
 
 Amount CWallet::GetWatchOnlyBalance() const {
     LOCK2(cs_main, cs_wallet);
 
     Amount nTotal = Amount::zero();
     for (const auto &entry : mapWallet) {
         const CWalletTx *pcoin = &entry.second;
         if (pcoin->IsTrusted()) {
             nTotal += pcoin->GetAvailableWatchOnlyCredit();
         }
     }
 
     return nTotal;
 }
 
 Amount CWallet::GetUnconfirmedWatchOnlyBalance() const {
     LOCK2(cs_main, cs_wallet);
 
     Amount nTotal = Amount::zero();
     for (const auto &entry : mapWallet) {
         const CWalletTx *pcoin = &entry.second;
         if (!pcoin->IsTrusted() && pcoin->GetDepthInMainChain() == 0 &&
             pcoin->InMempool()) {
             nTotal += pcoin->GetAvailableWatchOnlyCredit();
         }
     }
 
     return nTotal;
 }
 
 Amount CWallet::GetImmatureWatchOnlyBalance() const {
     LOCK2(cs_main, cs_wallet);
 
     Amount nTotal = Amount::zero();
     for (const auto &entry : mapWallet) {
         const CWalletTx *pcoin = &entry.second;
         nTotal += pcoin->GetImmatureWatchOnlyCredit();
     }
 
     return nTotal;
 }
 
 // Calculate total balance in a different way from GetBalance. The biggest
 // difference is that GetBalance sums up all unspent TxOuts paying to the
 // wallet, while this sums up both spent and unspent TxOuts paying to the
 // wallet, and then subtracts the values of TxIns spending from the wallet. This
 // also has fewer restrictions on which unconfirmed transactions are considered
 // trusted.
 Amount CWallet::GetLegacyBalance(const isminefilter &filter, int minDepth,
                                  const std::string *account) const {
     LOCK2(cs_main, cs_wallet);
 
     Amount balance = Amount::zero();
     for (const auto &entry : mapWallet) {
         const CWalletTx &wtx = entry.second;
         const int depth = wtx.GetDepthInMainChain();
         if (depth < 0 || !CheckFinalTx(*wtx.tx) || wtx.IsImmatureCoinBase()) {
 
             continue;
         }
 
         // Loop through tx outputs and add incoming payments. For outgoing txs,
         // treat change outputs specially, as part of the amount debited.
         Amount debit = wtx.GetDebit(filter);
         const bool outgoing = debit > Amount::zero();
         for (const CTxOut &out : wtx.tx->vout) {
             if (outgoing && IsChange(out)) {
                 debit -= out.nValue;
             } else if (IsMine(out) & filter && depth >= minDepth &&
                        (!account ||
                         *account == GetLabelName(out.scriptPubKey))) {
                 balance += out.nValue;
             }
         }
 
         // For outgoing txs, subtract amount debited.
         if (outgoing && (!account || *account == wtx.strFromAccount)) {
             balance -= debit;
         }
     }
 
     if (account) {
         balance += CWalletDB(*dbw).GetAccountCreditDebit(*account);
     }
 
     return balance;
 }
 
 Amount CWallet::GetAvailableBalance(const CCoinControl *coinControl) const {
     LOCK2(cs_main, cs_wallet);
 
     Amount balance = Amount::zero();
     std::vector<COutput> vCoins;
     AvailableCoins(vCoins, true, coinControl);
     for (const COutput &out : vCoins) {
         if (out.fSpendable) {
             balance += out.tx->tx->vout[out.i].nValue;
         }
     }
     return balance;
 }
 
 void CWallet::AvailableCoins(std::vector<COutput> &vCoins, bool fOnlySafe,
                              const CCoinControl *coinControl,
                              const Amount nMinimumAmount,
                              const Amount nMaximumAmount,
                              const Amount nMinimumSumAmount,
                              const uint64_t nMaximumCount, const int nMinDepth,
                              const int nMaxDepth) const {
     vCoins.clear();
     Amount nTotal = Amount::zero();
 
     LOCK2(cs_main, cs_wallet);
     for (const auto &entry : mapWallet) {
         const TxId &wtxid = entry.first;
         const CWalletTx *pcoin = &entry.second;
 
         if (!CheckFinalTx(*pcoin->tx)) {
             continue;
         }
 
         if (pcoin->IsImmatureCoinBase()) {
             continue;
         }
 
         int nDepth = pcoin->GetDepthInMainChain();
         if (nDepth < 0) {
             continue;
         }
 
         // We should not consider coins which aren't at least in our mempool.
         // It's possible for these to be conflicted via ancestors which we may
         // never be able to detect.
         if (nDepth == 0 && !pcoin->InMempool()) {
             continue;
         }
 
         bool safeTx = pcoin->IsTrusted();
 
         // Bitcoin-ABC: Removed check that prevents consideration of coins from
         // transactions that are replacing other transactions. This check based
         // on pcoin->mapValue.count("replaces_txid") which was not being set
         // anywhere.
 
         // Similarly, we should not consider coins from transactions that have
         // been replaced. In the example above, we would want to prevent
         // creation of a transaction A' spending an output of A, because if
         // transaction B were initially confirmed, conflicting with A and A', we
         // wouldn't want to the user to create a transaction D intending to
         // replace A', but potentially resulting in a scenario where A, A', and
         // D could all be accepted (instead of just B and D, or just A and A'
         // like the user would want).
 
         // Bitcoin-ABC: retained this check as 'replaced_by_txid' is still set
         // in the wallet code.
         if (nDepth == 0 && pcoin->mapValue.count("replaced_by_txid")) {
             safeTx = false;
         }
 
         if (fOnlySafe && !safeTx) {
             continue;
         }
 
         if (nDepth < nMinDepth || nDepth > nMaxDepth) {
             continue;
         }
 
         for (uint32_t i = 0; i < pcoin->tx->vout.size(); i++) {
             if (pcoin->tx->vout[i].nValue < nMinimumAmount ||
                 pcoin->tx->vout[i].nValue > nMaximumAmount) {
                 continue;
             }
 
             if (coinControl && coinControl->HasSelected() &&
                 !coinControl->fAllowOtherInputs &&
                 !coinControl->IsSelected(COutPoint(entry.first, i))) {
                 continue;
             }
 
             if (IsLockedCoin(entry.first, i)) {
                 continue;
             }
 
             if (IsSpent(wtxid, i)) {
                 continue;
             }
 
             isminetype mine = IsMine(pcoin->tx->vout[i]);
 
             if (mine == ISMINE_NO) {
                 continue;
             }
 
             bool fSpendableIn = ((mine & ISMINE_SPENDABLE) != ISMINE_NO) ||
                                 (coinControl && coinControl->fAllowWatchOnly &&
                                  (mine & ISMINE_WATCH_SOLVABLE) != ISMINE_NO);
             bool fSolvableIn =
                 (mine & (ISMINE_SPENDABLE | ISMINE_WATCH_SOLVABLE)) !=
                 ISMINE_NO;
 
             vCoins.push_back(
                 COutput(pcoin, i, nDepth, fSpendableIn, fSolvableIn, safeTx));
 
             // Checks the sum amount of all UTXO's.
             if (nMinimumSumAmount != MAX_MONEY) {
                 nTotal += pcoin->tx->vout[i].nValue;
 
                 if (nTotal >= nMinimumSumAmount) {
                     return;
                 }
             }
 
             // Checks the maximum number of UTXO's.
             if (nMaximumCount > 0 && vCoins.size() >= nMaximumCount) {
                 return;
             }
         }
     }
 }
 
 std::map<CTxDestination, std::vector<COutput>> CWallet::ListCoins() const {
     // TODO: Add AssertLockHeld(cs_wallet) here.
     //
     // Because the return value from this function contains pointers to
     // CWalletTx objects, callers to this function really should acquire the
     // cs_wallet lock before calling it. However, the current caller doesn't
     // acquire this lock yet. There was an attempt to add the missing lock in
     // https://github.com/bitcoin/bitcoin/pull/10340, but that change has been
     // postponed until after https://github.com/bitcoin/bitcoin/pull/10244 to
     // avoid adding some extra complexity to the Qt code.
 
     std::map<CTxDestination, std::vector<COutput>> result;
 
     std::vector<COutput> availableCoins;
     AvailableCoins(availableCoins);
 
     LOCK2(cs_main, cs_wallet);
     for (auto &coin : availableCoins) {
         CTxDestination address;
         if (coin.fSpendable &&
             ExtractDestination(
                 FindNonChangeParentOutput(*coin.tx->tx, coin.i).scriptPubKey,
                 address)) {
             result[address].emplace_back(std::move(coin));
         }
     }
 
     std::vector<COutPoint> lockedCoins;
     ListLockedCoins(lockedCoins);
     for (const auto &output : lockedCoins) {
         auto it = mapWallet.find(output.GetTxId());
         if (it != mapWallet.end()) {
             int depth = it->second.GetDepthInMainChain();
             if (depth >= 0 && output.GetN() < it->second.tx->vout.size() &&
                 IsMine(it->second.tx->vout[output.GetN()]) ==
                     ISMINE_SPENDABLE) {
                 CTxDestination address;
                 if (ExtractDestination(
                         FindNonChangeParentOutput(*it->second.tx, output.GetN())
                             .scriptPubKey,
                         address)) {
                     result[address].emplace_back(
                         &it->second, output.GetN(), depth, true /* spendable */,
                         true /* solvable */, false /* safe */);
                 }
             }
         }
     }
 
     return result;
 }
 
 const CTxOut &CWallet::FindNonChangeParentOutput(const CTransaction &tx,
                                                  int output) const {
     const CTransaction *ptx = &tx;
     int n = output;
     while (IsChange(ptx->vout[n]) && ptx->vin.size() > 0) {
         const COutPoint &prevout = ptx->vin[0].prevout;
         auto it = mapWallet.find(prevout.GetTxId());
         if (it == mapWallet.end() ||
             it->second.tx->vout.size() <= prevout.GetN() ||
             !IsMine(it->second.tx->vout[prevout.GetN()])) {
             break;
         }
         ptx = it->second.tx.get();
         n = prevout.GetN();
     }
     return ptx->vout[n];
 }
 
 static void ApproximateBestSubset(const std::vector<CInputCoin> &vValue,
                                   const Amount &nTotalLower,
                                   const Amount &nTargetValue,
                                   std::vector<char> &vfBest, Amount &nBest,
                                   int iterations = 1000) {
     std::vector<char> vfIncluded;
 
     vfBest.assign(vValue.size(), true);
     nBest = nTotalLower;
 
     FastRandomContext insecure_rand;
 
     for (int nRep = 0; nRep < iterations && nBest != nTargetValue; nRep++) {
         vfIncluded.assign(vValue.size(), false);
         Amount nTotal = Amount::zero();
         bool fReachedTarget = false;
         for (int nPass = 0; nPass < 2 && !fReachedTarget; nPass++) {
             for (size_t i = 0; i < vValue.size(); i++) {
                 // The solver here uses a randomized algorithm, the randomness
                 // serves no real security purpose but is just needed to prevent
                 // degenerate behavior and it is important that the rng is fast.
                 // We do not use a constant random sequence, because there may
                 // be some privacy improvement by making the selection random.
                 if (nPass == 0 ? insecure_rand.randbool() : !vfIncluded[i]) {
                     nTotal += vValue[i].txout.nValue;
                     vfIncluded[i] = true;
                     if (nTotal >= nTargetValue) {
                         fReachedTarget = true;
                         if (nTotal < nBest) {
                             nBest = nTotal;
                             vfBest = vfIncluded;
                         }
 
                         nTotal -= vValue[i].txout.nValue;
                         vfIncluded[i] = false;
                     }
                 }
             }
         }
     }
 }
 
 bool CWallet::SelectCoinsMinConf(const Amount nTargetValue, const int nConfMine,
                                  const int nConfTheirs,
                                  const uint64_t nMaxAncestors,
                                  std::vector<COutput> vCoins,
                                  std::set<CInputCoin> &setCoinsRet,
                                  Amount &nValueRet) const {
     setCoinsRet.clear();
     nValueRet = Amount::zero();
 
     // List of values less than target
     boost::optional<CInputCoin> coinLowestLarger;
     std::vector<CInputCoin> vValue;
     Amount nTotalLower = Amount::zero();
 
     random_shuffle(vCoins.begin(), vCoins.end(), GetRandInt);
 
     for (const COutput &output : vCoins) {
         if (!output.fSpendable) {
             continue;
         }
 
         const CWalletTx *pcoin = output.tx;
 
         if (output.nDepth <
             (pcoin->IsFromMe(ISMINE_ALL) ? nConfMine : nConfTheirs)) {
             continue;
         }
 
         if (!g_mempool.TransactionWithinChainLimit(pcoin->GetId(),
                                                    nMaxAncestors)) {
             continue;
         }
 
         int i = output.i;
         CInputCoin coin = CInputCoin(pcoin, i);
 
         if (coin.txout.nValue == nTargetValue) {
             setCoinsRet.insert(coin);
             nValueRet += coin.txout.nValue;
             return true;
         } else if (coin.txout.nValue < nTargetValue + MIN_CHANGE) {
             vValue.push_back(coin);
             nTotalLower += coin.txout.nValue;
         } else if (!coinLowestLarger ||
                    coin.txout.nValue < coinLowestLarger->txout.nValue) {
             coinLowestLarger = coin;
         }
     }
 
     if (nTotalLower == nTargetValue) {
         for (unsigned int i = 0; i < vValue.size(); ++i) {
             setCoinsRet.insert(vValue[i]);
             nValueRet += vValue[i].txout.nValue;
         }
 
         return true;
     }
 
     if (nTotalLower < nTargetValue) {
         if (!coinLowestLarger) {
             return false;
         }
 
         setCoinsRet.insert(coinLowestLarger.get());
         nValueRet += coinLowestLarger->txout.nValue;
         return true;
     }
 
     // Solve subset sum by stochastic approximation
     std::sort(vValue.begin(), vValue.end(), CompareValueOnly());
     std::reverse(vValue.begin(), vValue.end());
     std::vector<char> vfBest;
     Amount nBest;
 
     ApproximateBestSubset(vValue, nTotalLower, nTargetValue, vfBest, nBest);
     if (nBest != nTargetValue && nTotalLower >= nTargetValue + MIN_CHANGE) {
         ApproximateBestSubset(vValue, nTotalLower, nTargetValue + MIN_CHANGE,
                               vfBest, nBest);
     }
 
     // If we have a bigger coin and (either the stochastic approximation didn't
     // find a good solution, or the next bigger coin is closer), return the
     // bigger coin.
     if (coinLowestLarger &&
         ((nBest != nTargetValue && nBest < nTargetValue + MIN_CHANGE) ||
          coinLowestLarger->txout.nValue <= nBest)) {
         setCoinsRet.insert(coinLowestLarger.get());
         nValueRet += coinLowestLarger->txout.nValue;
     } else {
         for (unsigned int i = 0; i < vValue.size(); i++) {
             if (vfBest[i]) {
                 setCoinsRet.insert(vValue[i]);
                 nValueRet += vValue[i].txout.nValue;
             }
         }
 
         if (LogAcceptCategory(BCLog::SELECTCOINS)) {
             LogPrint(BCLog::SELECTCOINS, "SelectCoins() best subset: ");
             for (size_t i = 0; i < vValue.size(); i++) {
                 if (vfBest[i]) {
                     LogPrint(BCLog::SELECTCOINS, "%s ",
                              FormatMoney(vValue[i].txout.nValue));
                 }
             }
             LogPrint(BCLog::SELECTCOINS, "total %s\n", FormatMoney(nBest));
         }
     }
 
     return true;
 }
 
 bool CWallet::SelectCoins(const std::vector<COutput> &vAvailableCoins,
                           const Amount nTargetValue,
                           std::set<CInputCoin> &setCoinsRet, Amount &nValueRet,
                           const CCoinControl *coinControl) const {
     std::vector<COutput> vCoins(vAvailableCoins);
 
     // coin control -> return all selected outputs (we want all selected to go
     // into the transaction for sure).
     if (coinControl && coinControl->HasSelected() &&
         !coinControl->fAllowOtherInputs) {
         for (const COutput &out : vCoins) {
             if (!out.fSpendable) {
                 continue;
             }
 
             nValueRet += out.tx->tx->vout[out.i].nValue;
             setCoinsRet.insert(CInputCoin(out.tx, out.i));
         }
 
         return (nValueRet >= nTargetValue);
     }
 
     // Calculate value from preset inputs and store them.
     std::set<CInputCoin> setPresetCoins;
     Amount nValueFromPresetInputs = Amount::zero();
 
     std::vector<COutPoint> vPresetInputs;
     if (coinControl) {
         coinControl->ListSelected(vPresetInputs);
     }
 
     for (const COutPoint &outpoint : vPresetInputs) {
         std::map<TxId, CWalletTx>::const_iterator it =
             mapWallet.find(outpoint.GetTxId());
         if (it == mapWallet.end()) {
             // TODO: Allow non-wallet inputs
             return false;
         }
 
         const CWalletTx *pcoin = &it->second;
         // Clearly invalid input, fail.
         if (pcoin->tx->vout.size() <= outpoint.GetN()) {
             return false;
         }
 
         nValueFromPresetInputs += pcoin->tx->vout[outpoint.GetN()].nValue;
         setPresetCoins.insert(CInputCoin(pcoin, outpoint.GetN()));
     }
 
     // Remove preset inputs from vCoins.
     for (std::vector<COutput>::iterator it = vCoins.begin();
          it != vCoins.end() && coinControl && coinControl->HasSelected();) {
         if (setPresetCoins.count(CInputCoin(it->tx, it->i))) {
             it = vCoins.erase(it);
         } else {
             ++it;
         }
     }
 
     size_t nMaxChainLength = std::min(
         gArgs.GetArg("-limitancestorcount", DEFAULT_ANCESTOR_LIMIT),
         gArgs.GetArg("-limitdescendantcount", DEFAULT_DESCENDANT_LIMIT));
     bool fRejectLongChains = gArgs.GetBoolArg(
         "-walletrejectlongchains", DEFAULT_WALLET_REJECT_LONG_CHAINS);
 
     bool res =
         nTargetValue <= nValueFromPresetInputs ||
         SelectCoinsMinConf(nTargetValue - nValueFromPresetInputs, 1, 6, 0,
                            vCoins, setCoinsRet, nValueRet) ||
         SelectCoinsMinConf(nTargetValue - nValueFromPresetInputs, 1, 1, 0,
                            vCoins, setCoinsRet, nValueRet) ||
         (bSpendZeroConfChange &&
          SelectCoinsMinConf(nTargetValue - nValueFromPresetInputs, 0, 1, 2,
                             vCoins, setCoinsRet, nValueRet)) ||
         (bSpendZeroConfChange &&
          SelectCoinsMinConf(nTargetValue - nValueFromPresetInputs, 0, 1,
                             std::min((size_t)4, nMaxChainLength / 3), vCoins,
                             setCoinsRet, nValueRet)) ||
         (bSpendZeroConfChange &&
          SelectCoinsMinConf(nTargetValue - nValueFromPresetInputs, 0, 1,
                             nMaxChainLength / 2, vCoins, setCoinsRet,
                             nValueRet)) ||
         (bSpendZeroConfChange &&
          SelectCoinsMinConf(nTargetValue - nValueFromPresetInputs, 0, 1,
                             nMaxChainLength, vCoins, setCoinsRet, nValueRet)) ||
         (bSpendZeroConfChange && !fRejectLongChains &&
          SelectCoinsMinConf(nTargetValue - nValueFromPresetInputs, 0, 1,
                             std::numeric_limits<uint64_t>::max(), vCoins,
                             setCoinsRet, nValueRet));
 
     // Because SelectCoinsMinConf clears the setCoinsRet, we now add the
     // possible inputs to the coinset.
     setCoinsRet.insert(setPresetCoins.begin(), setPresetCoins.end());
 
     // Add preset inputs to the total value selected.
     nValueRet += nValueFromPresetInputs;
 
     return res;
 }
 
 bool CWallet::SignTransaction(CMutableTransaction &tx) {
     // sign the new tx
     CTransaction txNewConst(tx);
     int nIn = 0;
     for (auto &input : tx.vin) {
         auto mi = mapWallet.find(input.prevout.GetTxId());
         if (mi == mapWallet.end() ||
             input.prevout.GetN() >= mi->second.tx->vout.size()) {
             return false;
         }
         const CScript &scriptPubKey =
             mi->second.tx->vout[input.prevout.GetN()].scriptPubKey;
         const Amount amount = mi->second.tx->vout[input.prevout.GetN()].nValue;
         SignatureData sigdata;
         SigHashType sigHashType = SigHashType().withForkId();
         if (!ProduceSignature(TransactionSignatureCreator(
                                   this, &txNewConst, nIn, amount, sigHashType),
                               scriptPubKey, sigdata)) {
             return false;
         }
         UpdateTransaction(tx, nIn, sigdata);
         nIn++;
     }
     return true;
 }
 
 bool CWallet::FundTransaction(CMutableTransaction &tx, Amount &nFeeRet,
                               int &nChangePosInOut, std::string &strFailReason,
                               bool lockUnspents,
                               const std::set<int> &setSubtractFeeFromOutputs,
                               CCoinControl coinControl, bool keepReserveKey) {
     std::vector<CRecipient> vecSend;
 
     // Turn the txout set into a CRecipient vector.
     for (size_t idx = 0; idx < tx.vout.size(); idx++) {
         const CTxOut &txOut = tx.vout[idx];
         CRecipient recipient = {txOut.scriptPubKey, txOut.nValue,
                                 setSubtractFeeFromOutputs.count(idx) == 1};
         vecSend.push_back(recipient);
     }
 
     coinControl.fAllowOtherInputs = true;
 
     for (const CTxIn &txin : tx.vin) {
         coinControl.Select(txin.prevout);
     }
 
     CReserveKey reservekey(this);
     CTransactionRef tx_new;
     if (!CreateTransaction(vecSend, tx_new, reservekey, nFeeRet,
                            nChangePosInOut, strFailReason, coinControl,
                            false)) {
         return false;
     }
 
     if (nChangePosInOut != -1) {
         tx.vout.insert(tx.vout.begin() + nChangePosInOut,
                        tx_new->vout[nChangePosInOut]);
         // we dont have the normal Create/Commit cycle, and dont want to
         // risk reusing change, so just remove the key from the keypool
         // here.
         if (!IsDeprecatedRPCEnabled(gArgs, "fundrawtransaction")) {
             reservekey.KeepKey();
         }
     }
 
     // Copy output sizes from new transaction; they may have had the fee
     // subtracted from them.
     for (size_t idx = 0; idx < tx.vout.size(); idx++) {
         tx.vout[idx].nValue = tx_new->vout[idx].nValue;
     }
 
     // Add new txins (keeping original txin scriptSig/order)
     for (const CTxIn &txin : tx_new->vin) {
         if (!coinControl.IsSelected(txin.prevout)) {
             tx.vin.push_back(txin);
 
             if (lockUnspents) {
                 LOCK2(cs_main, cs_wallet);
                 LockCoin(txin.prevout);
             }
         }
     }
 
     // DEPRECATED, remove in 0.20 with -reserveChangeKey
     // Optionally keep the change output key.
     if (IsDeprecatedRPCEnabled(gArgs, "fundrawtransaction")) {
 
         if (keepReserveKey) {
             reservekey.KeepKey();
         }
     }
 
     return true;
 }
 
 bool CWallet::CreateTransaction(const std::vector<CRecipient> &vecSend,
                                 CTransactionRef &tx, CReserveKey &reservekey,
                                 Amount &nFeeRet, int &nChangePosInOut,
                                 std::string &strFailReason,
                                 const CCoinControl &coinControl, bool sign) {
     Amount nValue = Amount::zero();
     int nChangePosRequest = nChangePosInOut;
     unsigned int nSubtractFeeFromAmount = 0;
     for (const auto &recipient : vecSend) {
         if (nValue < Amount::zero() || recipient.nAmount < Amount::zero()) {
             strFailReason = _("Transaction amounts must not be negative");
             return false;
         }
 
         nValue += recipient.nAmount;
 
         if (recipient.fSubtractFeeFromAmount) {
             nSubtractFeeFromAmount++;
         }
     }
 
     if (vecSend.empty()) {
         strFailReason = _("Transaction must have at least one recipient");
         return false;
     }
 
     CMutableTransaction txNew;
 
     // Discourage fee sniping.
     //
     // For a large miner the value of the transactions in the best block and the
     // mempool can exceed the cost of deliberately attempting to mine two blocks
     // to orphan the current best block. By setting nLockTime such that only the
     // next block can include the transaction, we discourage this practice as
     // the height restricted and limited blocksize gives miners considering fee
     // sniping fewer options for pulling off this attack.
     //
     // A simple way to think about this is from the wallet's point of view we
     // always want the blockchain to move forward. By setting nLockTime this way
     // we're basically making the statement that we only want this transaction
     // to appear in the next block; we don't want to potentially encourage
     // reorgs by allowing transactions to appear at lower heights than the next
     // block in forks of the best chain.
     //
     // Of course, the subsidy is high enough, and transaction volume low enough,
     // that fee sniping isn't a problem yet, but by implementing a fix now we
     // ensure code won't be written that makes assumptions about nLockTime that
     // preclude a fix later.
     txNew.nLockTime = chainActive.Height();
 
     // Secondly occasionally randomly pick a nLockTime even further back, so
     // that transactions that are delayed after signing for whatever reason,
     // e.g. high-latency mix networks and some CoinJoin implementations, have
     // better privacy.
     if (GetRandInt(10) == 0) {
         txNew.nLockTime = std::max(0, (int)txNew.nLockTime - GetRandInt(100));
     }
 
     assert(txNew.nLockTime <= (unsigned int)chainActive.Height());
     assert(txNew.nLockTime < LOCKTIME_THRESHOLD);
 
     {
         std::set<CInputCoin> setCoins;
         LOCK2(cs_main, cs_wallet);
 
         std::vector<COutput> vAvailableCoins;
         AvailableCoins(vAvailableCoins, true, &coinControl);
 
         // Create change script that will be used if we need change
         // TODO: pass in scriptChange instead of reservekey so
         // change transaction isn't always pay-to-bitcoin-address
         CScript scriptChange;
 
         // coin control: send change to custom address
         if (!boost::get<CNoDestination>(&coinControl.destChange)) {
             scriptChange = GetScriptForDestination(coinControl.destChange);
 
             // no coin control: send change to newly generated address
         } else {
             // Note: We use a new key here to keep it from being obvious
             // which side is the change.
             //  The drawback is that by not reusing a previous key, the
             //  change may be lost if a backup is restored, if the backup
             //  doesn't have the new private key for the change. If we
             //  reused the old key, it would be possible to add code to look
             //  for and rediscover unknown transactions that were written
             //  with keys of ours to recover post-backup change.
 
             // Reserve a new key pair from key pool
             CPubKey vchPubKey;
             bool ret;
             ret = reservekey.GetReservedKey(vchPubKey, true);
             if (!ret) {
                 strFailReason =
                     _("Keypool ran out, please call keypoolrefill first");
                 return false;
             }
 
             LearnRelatedScripts(vchPubKey, g_change_type);
             scriptChange = GetScriptForDestination(
                 GetDestinationForKey(vchPubKey, g_change_type));
         }
         CTxOut change_prototype_txout(Amount::zero(), scriptChange);
         size_t change_prototype_size =
             GetSerializeSize(change_prototype_txout, SER_DISK, 0);
 
         nFeeRet = Amount::zero();
         bool pick_new_inputs = true;
         Amount nValueIn = Amount::zero();
         // Start with no fee and loop until there is enough fee
         while (true) {
             nChangePosInOut = nChangePosRequest;
             txNew.vin.clear();
             txNew.vout.clear();
             bool fFirst = true;
 
             Amount nValueToSelect = nValue;
             if (nSubtractFeeFromAmount == 0) {
                 nValueToSelect += nFeeRet;
             }
 
             double dPriority = 0;
             // vouts to the payees
             for (const auto &recipient : vecSend) {
                 CTxOut txout(recipient.nAmount, recipient.scriptPubKey);
 
                 if (recipient.fSubtractFeeFromAmount) {
                     // Subtract fee equally from each selected recipient.
                     txout.nValue -= nFeeRet / int(nSubtractFeeFromAmount);
 
                     // First receiver pays the remainder not divisible by output
                     // count.
                     if (fFirst) {
                         fFirst = false;
                         txout.nValue -= nFeeRet % int(nSubtractFeeFromAmount);
                     }
                 }
 
                 if (IsDust(txout, dustRelayFee)) {
                     if (recipient.fSubtractFeeFromAmount &&
                         nFeeRet > Amount::zero()) {
                         if (txout.nValue < Amount::zero()) {
                             strFailReason = _("The transaction amount is "
                                               "too small to pay the fee");
                         } else {
                             strFailReason =
                                 _("The transaction amount is too small to "
                                   "send after the fee has been deducted");
                         }
                     } else {
                         strFailReason = _("Transaction amount too small");
                     }
 
                     return false;
                 }
 
                 txNew.vout.push_back(txout);
             }
 
             // Choose coins to use
             if (pick_new_inputs) {
                 nValueIn = Amount::zero();
                 setCoins.clear();
                 if (!SelectCoins(vAvailableCoins, nValueToSelect, setCoins,
                                  nValueIn, &coinControl)) {
                     strFailReason = _("Insufficient funds");
                     return false;
                 }
             }
 
             for (const auto &pcoin : setCoins) {
                 Amount nCredit = pcoin.txout.nValue;
                 // The coin age after the next block (depth+1) is used instead
                 // of the current, reflecting an assumption the user would
                 // accept a bit more delay for a chance at a free transaction.
                 // But mempool inputs might still be in the mempool, so their
                 // age stays 0.
                 int age = pcoin.wtx->GetDepthInMainChain();
                 assert(age >= 0);
                 if (age != 0) {
                     age += 1;
                 }
 
                 dPriority += (age * nCredit) / SATOSHI;
             }
 
             const Amount nChange = nValueIn - nValueToSelect;
             if (nChange > Amount::zero()) {
                 // Fill a vout to ourself.
                 CTxOut newTxOut(nChange, scriptChange);
 
                 // We do not move dust-change to fees, because the sender would
                 // end up paying more than requested. This would be against the
                 // purpose of the all-inclusive feature. So instead we raise the
                 // change and deduct from the recipient.
                 if (nSubtractFeeFromAmount > 0 &&
                     IsDust(newTxOut, dustRelayFee)) {
                     Amount nDust = GetDustThreshold(newTxOut, dustRelayFee) -
                                    newTxOut.nValue;
                     // Raise change until no more dust.
                     newTxOut.nValue += nDust;
                     // Subtract from first recipient.
                     for (unsigned int i = 0; i < vecSend.size(); i++) {
                         if (vecSend[i].fSubtractFeeFromAmount) {
                             txNew.vout[i].nValue -= nDust;
                             if (IsDust(txNew.vout[i], dustRelayFee)) {
                                 strFailReason =
                                     _("The transaction amount is too small "
                                       "to send after the fee has been "
                                       "deducted");
                                 return false;
                             }
 
                             break;
                         }
                     }
                 }
 
                 // Never create dust outputs; if we would, just add the dust to
                 // the fee.
                 if (IsDust(newTxOut, dustRelayFee)) {
                     nChangePosInOut = -1;
                     nFeeRet += nChange;
                 } else {
                     if (nChangePosInOut == -1) {
                         // Insert change txn at random position:
                         nChangePosInOut = GetRandInt(txNew.vout.size() + 1);
                     } else if ((unsigned int)nChangePosInOut >
                                txNew.vout.size()) {
                         strFailReason = _("Change index out of range");
                         return false;
                     }
 
                     std::vector<CTxOut>::iterator position =
                         txNew.vout.begin() + nChangePosInOut;
                     txNew.vout.insert(position, newTxOut);
                 }
             } else {
                 nChangePosInOut = -1;
             }
 
             // Fill vin
             //
             // Note how the sequence number is set to non-maxint so that the
             // nLockTime set above actually works.
             for (const auto &coin : setCoins) {
                 txNew.vin.push_back(
                     CTxIn(coin.outpoint, CScript(),
                           std::numeric_limits<uint32_t>::max() - 1));
             }
 
             // Fill in dummy signatures for fee calculation.
             if (!DummySignTx(txNew, setCoins)) {
                 strFailReason = _("Signing transaction failed");
                 return false;
             }
 
             CTransaction txNewConst(txNew);
             unsigned int nBytes = txNewConst.GetTotalSize();
             dPriority = txNewConst.ComputePriority(dPriority, nBytes);
 
             // Remove scriptSigs to eliminate the fee calculation dummy
             // signatures.
             for (auto &vin : txNew.vin) {
                 vin.scriptSig = CScript();
             }
 
             Amount nFeeNeeded = GetMinimumFee(nBytes, g_mempool, coinControl);
 
             // If we made it here and we aren't even able to meet the relay fee
             // on the next pass, give up because we must be at the maximum
             // allowed fee.
             Amount minFee = GetConfig().GetMinFeePerKB().GetFeeCeiling(nBytes);
             if (nFeeNeeded < minFee) {
                 strFailReason = _("Transaction too large for fee policy");
                 return false;
             }
 
             if (nFeeRet >= nFeeNeeded) {
                 // Reduce fee to only the needed amount if possible. This
                 // prevents potential overpayment in fees if the coins selected
                 // to meet nFeeNeeded result in a transaction that requires less
                 // fee than the prior iteration.
 
                 // TODO: The case where nSubtractFeeFromAmount > 0 remains to be
                 // addressed because it requires returning the fee to the payees
                 // and not the change output.
 
                 // If we have no change and a big enough excess fee, then try to
                 // construct transaction again only without picking new inputs.
                 // We now know we only need the smaller fee (because of reduced
                 // tx size) and so we should add a change output. Only try this
                 // once.
                 Amount fee_needed_for_change = GetMinimumFee(
                     change_prototype_size, g_mempool, coinControl);
                 Amount minimum_value_for_change =
                     GetDustThreshold(change_prototype_txout, dustRelayFee);
                 Amount max_excess_fee =
                     fee_needed_for_change + minimum_value_for_change;
                 if (nFeeRet > nFeeNeeded + max_excess_fee &&
                     nChangePosInOut == -1 && nSubtractFeeFromAmount == 0 &&
                     pick_new_inputs) {
                     pick_new_inputs = false;
                     nFeeRet = nFeeNeeded + fee_needed_for_change;
                     continue;
                 }
 
                 // If we have change output already, just increase it
                 if (nFeeRet > nFeeNeeded && nChangePosInOut != -1 &&
                     nSubtractFeeFromAmount == 0) {
                     Amount extraFeePaid = nFeeRet - nFeeNeeded;
                     std::vector<CTxOut>::iterator change_position =
                         txNew.vout.begin() + nChangePosInOut;
                     change_position->nValue += extraFeePaid;
                     nFeeRet -= extraFeePaid;
                 }
 
                 // Done, enough fee included.
                 break;
             } else if (!pick_new_inputs) {
                 // This shouldn't happen, we should have had enough excess fee
                 // to pay for the new output and still meet nFeeNeeded
                 strFailReason =
                     _("Transaction fee and change calculation failed");
                 return false;
             }
 
             // Try to reduce change to include necessary fee.
             if (nChangePosInOut != -1 && nSubtractFeeFromAmount == 0) {
                 Amount additionalFeeNeeded = nFeeNeeded - nFeeRet;
                 std::vector<CTxOut>::iterator change_position =
                     txNew.vout.begin() + nChangePosInOut;
                 // Only reduce change if remaining amount is still a large
                 // enough output.
                 if (change_position->nValue >=
                     MIN_FINAL_CHANGE + additionalFeeNeeded) {
                     change_position->nValue -= additionalFeeNeeded;
                     nFeeRet += additionalFeeNeeded;
                     // Done, able to increase fee from change.
                     break;
                 }
             }
 
             // Include more fee and try again.
             nFeeRet = nFeeNeeded;
             continue;
         }
 
         if (nChangePosInOut == -1) {
             // Return any reserved key if we don't have change
             reservekey.ReturnKey();
         }
 
         if (sign) {
             SigHashType sigHashType = SigHashType().withForkId();
 
             CTransaction txNewConst(txNew);
             int nIn = 0;
             for (const auto &coin : setCoins) {
                 const CScript &scriptPubKey = coin.txout.scriptPubKey;
                 SignatureData sigdata;
 
                 if (!ProduceSignature(TransactionSignatureCreator(
                                           this, &txNewConst, nIn,
                                           coin.txout.nValue, sigHashType),
                                       scriptPubKey, sigdata)) {
                     strFailReason = _("Signing transaction failed");
                     return false;
                 }
 
                 UpdateTransaction(txNew, nIn, sigdata);
                 nIn++;
             }
         }
 
         // Return the constructed transaction data.
         tx = MakeTransactionRef(std::move(txNew));
 
         // Limit size.
         if (tx->GetTotalSize() >= MAX_STANDARD_TX_SIZE) {
             strFailReason = _("Transaction too large");
             return false;
         }
     }
 
     if (gArgs.GetBoolArg("-walletrejectlongchains",
                          DEFAULT_WALLET_REJECT_LONG_CHAINS)) {
         // Lastly, ensure this tx will pass the mempool's chain limits.
         LockPoints lp;
         CTxMemPoolEntry entry(tx, Amount::zero(), 0, 0, 0, Amount::zero(),
                               false, 0, lp);
         CTxMemPool::setEntries setAncestors;
         size_t nLimitAncestors =
             gArgs.GetArg("-limitancestorcount", DEFAULT_ANCESTOR_LIMIT);
         size_t nLimitAncestorSize =
             gArgs.GetArg("-limitancestorsize", DEFAULT_ANCESTOR_SIZE_LIMIT) *
             1000;
         size_t nLimitDescendants =
             gArgs.GetArg("-limitdescendantcount", DEFAULT_DESCENDANT_LIMIT);
         size_t nLimitDescendantSize =
             gArgs.GetArg("-limitdescendantsize",
                          DEFAULT_DESCENDANT_SIZE_LIMIT) *
             1000;
         std::string errString;
         if (!g_mempool.CalculateMemPoolAncestors(
                 entry, setAncestors, nLimitAncestors, nLimitAncestorSize,
                 nLimitDescendants, nLimitDescendantSize, errString)) {
             strFailReason = _("Transaction has too long of a mempool chain");
             return false;
         }
     }
 
     return true;
 }
 
 /**
  * Call after CreateTransaction unless you want to abort
  */
 bool CWallet::CommitTransaction(
     CTransactionRef tx, mapValue_t mapValue,
     std::vector<std::pair<std::string, std::string>> orderForm,
     std::string fromAccount, CReserveKey &reservekey, CConnman *connman,
     CValidationState &state) {
     LOCK2(cs_main, cs_wallet);
 
     CWalletTx wtxNew(this, std::move(tx));
     wtxNew.mapValue = std::move(mapValue);
     wtxNew.vOrderForm = std::move(orderForm);
     wtxNew.strFromAccount = std::move(fromAccount);
     wtxNew.fTimeReceivedIsTxTime = true;
     wtxNew.fFromMe = true;
 
     LogPrintf("CommitTransaction:\n%s", wtxNew.tx->ToString());
 
     // Take key pair from key pool so it won't be used again.
     reservekey.KeepKey();
 
     // Add tx to wallet, because if it has change it's also ours, otherwise just
     // for transaction history.
     AddToWallet(wtxNew);
 
     // Notify that old coins are spent.
     for (const CTxIn &txin : wtxNew.tx->vin) {
         CWalletTx &coin = mapWallet.at(txin.prevout.GetTxId());
         coin.BindWallet(this);
         NotifyTransactionChanged(this, coin.GetId(), CT_UPDATED);
     }
 
     // Track how many getdata requests our transaction gets.
     mapRequestCount[wtxNew.GetId()] = 0;
 
     // Get the inserted-CWalletTx from mapWallet so that the
     // fInMempool flag is cached properly
     CWalletTx &wtx = mapWallet.at(wtxNew.GetId());
 
     if (fBroadcastTransactions) {
         // Broadcast
         if (!wtx.AcceptToMemoryPool(maxTxFee, state)) {
             LogPrintf("CommitTransaction(): Transaction cannot be broadcast "
                       "immediately, %s\n",
                       state.GetRejectReason());
             // TODO: if we expect the failure to be long term or permanent,
             // instead delete wtx from the wallet and return failure.
         } else {
             wtx.RelayWalletTransaction(connman);
         }
     }
 
     return true;
 }
 
 void CWallet::ListAccountCreditDebit(const std::string &strAccount,
                                      std::list<CAccountingEntry> &entries) {
     CWalletDB walletdb(*dbw);
     return walletdb.ListAccountCreditDebit(strAccount, entries);
 }
 
 bool CWallet::AddAccountingEntry(const CAccountingEntry &acentry) {
     CWalletDB walletdb(*dbw);
     return AddAccountingEntry(acentry, &walletdb);
 }
 
 bool CWallet::AddAccountingEntry(const CAccountingEntry &acentry,
                                  CWalletDB *pwalletdb) {
     if (!pwalletdb->WriteAccountingEntry(++nAccountingEntryNumber, acentry)) {
         return false;
     }
 
     laccentries.push_back(acentry);
     CAccountingEntry &entry = laccentries.back();
     wtxOrdered.insert(std::make_pair(entry.nOrderPos, TxPair(nullptr, &entry)));
 
     return true;
 }
 
 DBErrors CWallet::LoadWallet(bool &fFirstRunRet) {
     LOCK2(cs_main, cs_wallet);
 
     fFirstRunRet = false;
     DBErrors nLoadWalletRet = CWalletDB(*dbw, "cr+").LoadWallet(this);
     if (nLoadWalletRet == DBErrors::NEED_REWRITE) {
         if (dbw->Rewrite("\x04pool")) {
             setInternalKeyPool.clear();
             setExternalKeyPool.clear();
             m_pool_key_to_index.clear();
             // Note: can't top-up keypool here, because wallet is locked.
             // User will be prompted to unlock wallet the next operation
             // that requires a new key.
         }
     }
 
     // This wallet is in its first run if all of these are empty
     fFirstRunRet = mapKeys.empty() && mapCryptedKeys.empty() &&
                    mapWatchKeys.empty() && setWatchOnly.empty() &&
                    mapScripts.empty();
 
     if (nLoadWalletRet != DBErrors::LOAD_OK) {
         return nLoadWalletRet;
     }
 
     uiInterface.LoadWallet(this);
 
     return DBErrors::LOAD_OK;
 }
 
 DBErrors CWallet::ZapSelectTx(std::vector<TxId> &txIdsIn,
                               std::vector<TxId> &txIdsOut) {
     AssertLockHeld(cs_wallet); // mapWallet
     DBErrors nZapSelectTxRet =
         CWalletDB(*dbw, "cr+").ZapSelectTx(txIdsIn, txIdsOut);
     for (const TxId &txid : txIdsOut) {
         mapWallet.erase(txid);
     }
 
     if (nZapSelectTxRet == DBErrors::NEED_REWRITE) {
         if (dbw->Rewrite("\x04pool")) {
             setInternalKeyPool.clear();
             setExternalKeyPool.clear();
             m_pool_key_to_index.clear();
             // Note: can't top-up keypool here, because wallet is locked.
             // User will be prompted to unlock wallet the next operation
             // that requires a new key.
         }
     }
 
     if (nZapSelectTxRet != DBErrors::LOAD_OK) {
         return nZapSelectTxRet;
     }
 
     MarkDirty();
 
     return DBErrors::LOAD_OK;
 }
 
 DBErrors CWallet::ZapWalletTx(std::vector<CWalletTx> &vWtx) {
     DBErrors nZapWalletTxRet = CWalletDB(*dbw, "cr+").ZapWalletTx(vWtx);
     if (nZapWalletTxRet == DBErrors::NEED_REWRITE) {
         if (dbw->Rewrite("\x04pool")) {
             LOCK(cs_wallet);
             setInternalKeyPool.clear();
             setExternalKeyPool.clear();
             m_pool_key_to_index.clear();
             // Note: can't top-up keypool here, because wallet is locked.
             // User will be prompted to unlock wallet the next operation
             // that requires a new key.
         }
     }
 
     if (nZapWalletTxRet != DBErrors::LOAD_OK) {
         return nZapWalletTxRet;
     }
 
     return DBErrors::LOAD_OK;
 }
 
 bool CWallet::SetAddressBook(const CTxDestination &address,
                              const std::string &strName,
                              const std::string &strPurpose) {
     bool fUpdated = false;
     {
         // mapAddressBook
         LOCK(cs_wallet);
         std::map<CTxDestination, CAddressBookData>::iterator mi =
             mapAddressBook.find(address);
         fUpdated = mi != mapAddressBook.end();
         mapAddressBook[address].name = strName;
         // Update purpose only if requested.
         if (!strPurpose.empty()) {
             mapAddressBook[address].purpose = strPurpose;
         }
     }
 
     NotifyAddressBookChanged(this, address, strName,
                              ::IsMine(*this, address) != ISMINE_NO, strPurpose,
                              (fUpdated ? CT_UPDATED : CT_NEW));
 
     if (!strPurpose.empty() &&
         !CWalletDB(*dbw).WritePurpose(address, strPurpose)) {
         return false;
     }
 
     return CWalletDB(*dbw).WriteName(address, strName);
 }
 
 bool CWallet::DelAddressBook(const CTxDestination &address) {
     {
         // mapAddressBook
         LOCK(cs_wallet);
 
         // Delete destdata tuples associated with address.
         for (const std::pair<std::string, std::string> &item :
              mapAddressBook[address].destdata) {
             CWalletDB(*dbw).EraseDestData(address, item.first);
         }
 
         mapAddressBook.erase(address);
     }
 
     NotifyAddressBookChanged(this, address, "",
                              ::IsMine(*this, address) != ISMINE_NO, "",
                              CT_DELETED);
 
     CWalletDB(*dbw).ErasePurpose(address);
     return CWalletDB(*dbw).EraseName(address);
 }
 
 const std::string &CWallet::GetLabelName(const CScript &scriptPubKey) const {
     CTxDestination address;
     if (ExtractDestination(scriptPubKey, address) &&
         !scriptPubKey.IsUnspendable()) {
         auto mi = mapAddressBook.find(address);
         if (mi != mapAddressBook.end()) {
             return mi->second.name;
         }
     }
     // A scriptPubKey that doesn't have an entry in the address book is
     // associated with the default label ("").
     const static std::string DEFAULT_LABEL_NAME;
     return DEFAULT_LABEL_NAME;
 }
 
 /**
  * Mark old keypool keys as used, and generate all new keys.
  */
 bool CWallet::NewKeyPool() {
     LOCK(cs_wallet);
     CWalletDB walletdb(*dbw);
 
     for (int64_t nIndex : setInternalKeyPool) {
         walletdb.ErasePool(nIndex);
     }
     setInternalKeyPool.clear();
 
     for (int64_t nIndex : setExternalKeyPool) {
         walletdb.ErasePool(nIndex);
     }
     setExternalKeyPool.clear();
 
     m_pool_key_to_index.clear();
 
     if (!TopUpKeyPool()) {
         return false;
     }
 
     LogPrintf("CWallet::NewKeyPool rewrote keypool\n");
     return true;
 }
 
 size_t CWallet::KeypoolCountExternalKeys() {
     // setExternalKeyPool
     AssertLockHeld(cs_wallet);
     return setExternalKeyPool.size();
 }
 
 void CWallet::LoadKeyPool(int64_t nIndex, const CKeyPool &keypool) {
     AssertLockHeld(cs_wallet);
     if (keypool.fInternal) {
         setInternalKeyPool.insert(nIndex);
     } else {
         setExternalKeyPool.insert(nIndex);
     }
     m_max_keypool_index = std::max(m_max_keypool_index, nIndex);
     m_pool_key_to_index[keypool.vchPubKey.GetID()] = nIndex;
 
     // If no metadata exists yet, create a default with the pool key's
     // creation time. Note that this may be overwritten by actually
     // stored metadata for that key later, which is fine.
     CKeyID keyid = keypool.vchPubKey.GetID();
     if (mapKeyMetadata.count(keyid) == 0) {
         mapKeyMetadata[keyid] = CKeyMetadata(keypool.nTime);
     }
 }
 
 bool CWallet::TopUpKeyPool(unsigned int kpSize) {
     LOCK(cs_wallet);
 
     if (IsLocked()) {
         return false;
     }
 
     // Top up key pool
     unsigned int nTargetSize;
     if (kpSize > 0) {
         nTargetSize = kpSize;
     } else {
         nTargetSize = std::max<int64_t>(
             gArgs.GetArg("-keypool", DEFAULT_KEYPOOL_SIZE), 0);
     }
 
     // count amount of available keys (internal, external)
     // make sure the keypool of external and internal keys fits the user
     // selected target (-keypool)
     int64_t missingExternal = std::max<int64_t>(
         std::max<int64_t>(nTargetSize, 1) - setExternalKeyPool.size(), 0);
     int64_t missingInternal = std::max<int64_t>(
         std::max<int64_t>(nTargetSize, 1) - setInternalKeyPool.size(), 0);
 
     if (!IsHDEnabled() || !CanSupportFeature(FEATURE_HD_SPLIT)) {
         // don't create extra internal keys
         missingInternal = 0;
     }
     bool internal = false;
     CWalletDB walletdb(*dbw);
     for (int64_t i = missingInternal + missingExternal; i--;) {
         if (i < missingInternal) {
             internal = true;
         }
 
         // How in the hell did you use so many keys?
         assert(m_max_keypool_index < std::numeric_limits<int64_t>::max());
         int64_t index = ++m_max_keypool_index;
 
         CPubKey pubkey(GenerateNewKey(walletdb, internal));
         if (!walletdb.WritePool(index, CKeyPool(pubkey, internal))) {
             throw std::runtime_error(std::string(__func__) +
                                      ": writing generated key failed");
         }
 
         if (internal) {
             setInternalKeyPool.insert(index);
         } else {
             setExternalKeyPool.insert(index);
         }
         m_pool_key_to_index[pubkey.GetID()] = index;
     }
     if (missingInternal + missingExternal > 0) {
         LogPrintf(
             "keypool added %d keys (%d internal), size=%u (%u internal)\n",
             missingInternal + missingExternal, missingInternal,
             setInternalKeyPool.size() + setExternalKeyPool.size(),
             setInternalKeyPool.size());
     }
 
     return true;
 }
 
 void CWallet::ReserveKeyFromKeyPool(int64_t &nIndex, CKeyPool &keypool,
                                     bool fRequestedInternal) {
     nIndex = -1;
     keypool.vchPubKey = CPubKey();
 
     LOCK(cs_wallet);
 
     if (!IsLocked()) {
         TopUpKeyPool();
     }
 
     bool fReturningInternal = IsHDEnabled() &&
                               CanSupportFeature(FEATURE_HD_SPLIT) &&
                               fRequestedInternal;
     std::set<int64_t> &setKeyPool =
         fReturningInternal ? setInternalKeyPool : setExternalKeyPool;
 
     // Get the oldest key
     if (setKeyPool.empty()) {
         return;
     }
 
     CWalletDB walletdb(*dbw);
 
     auto it = setKeyPool.begin();
     nIndex = *it;
     setKeyPool.erase(it);
     if (!walletdb.ReadPool(nIndex, keypool)) {
         throw std::runtime_error(std::string(__func__) + ": read failed");
     }
     if (!HaveKey(keypool.vchPubKey.GetID())) {
         throw std::runtime_error(std::string(__func__) +
                                  ": unknown key in key pool");
     }
     if (keypool.fInternal != fReturningInternal) {
         throw std::runtime_error(std::string(__func__) +
                                  ": keypool entry misclassified");
     }
 
     assert(keypool.vchPubKey.IsValid());
     m_pool_key_to_index.erase(keypool.vchPubKey.GetID());
     LogPrintf("keypool reserve %d\n", nIndex);
 }
 
 void CWallet::KeepKey(int64_t nIndex) {
     // Remove from key pool.
     CWalletDB walletdb(*dbw);
     walletdb.ErasePool(nIndex);
     LogPrintf("keypool keep %d\n", nIndex);
 }
 
 void CWallet::ReturnKey(int64_t nIndex, bool fInternal, const CPubKey &pubkey) {
     // Return to key pool
     {
         LOCK(cs_wallet);
         if (fInternal) {
             setInternalKeyPool.insert(nIndex);
         } else {
             setExternalKeyPool.insert(nIndex);
         }
         m_pool_key_to_index[pubkey.GetID()] = nIndex;
     }
 
     LogPrintf("keypool return %d\n", nIndex);
 }
 
 bool CWallet::GetKeyFromPool(CPubKey &result, bool internal) {
     CKeyPool keypool;
     LOCK(cs_wallet);
     int64_t nIndex = 0;
     ReserveKeyFromKeyPool(nIndex, keypool, internal);
     if (nIndex == -1) {
         if (IsLocked()) {
             return false;
         }
         CWalletDB walletdb(*dbw);
         result = GenerateNewKey(walletdb, internal);
         return true;
     }
 
     KeepKey(nIndex);
     result = keypool.vchPubKey;
 
     return true;
 }
 
 static int64_t GetOldestKeyTimeInPool(const std::set<int64_t> &setKeyPool,
                                       CWalletDB &walletdb) {
     if (setKeyPool.empty()) {
         return GetTime();
     }
 
     CKeyPool keypool;
     int64_t nIndex = *(setKeyPool.begin());
     if (!walletdb.ReadPool(nIndex, keypool)) {
         throw std::runtime_error(std::string(__func__) +
                                  ": read oldest key in keypool failed");
     }
 
     assert(keypool.vchPubKey.IsValid());
     return keypool.nTime;
 }
 
 int64_t CWallet::GetOldestKeyPoolTime() {
     LOCK(cs_wallet);
 
     CWalletDB walletdb(*dbw);
 
     // load oldest key from keypool, get time and return
     int64_t oldestKey = GetOldestKeyTimeInPool(setExternalKeyPool, walletdb);
     if (IsHDEnabled() && CanSupportFeature(FEATURE_HD_SPLIT)) {
         oldestKey = std::max(
             GetOldestKeyTimeInPool(setInternalKeyPool, walletdb), oldestKey);
     }
 
     return oldestKey;
 }
 
 std::map<CTxDestination, Amount> CWallet::GetAddressBalances() {
     std::map<CTxDestination, Amount> balances;
 
     LOCK(cs_wallet);
     for (std::pair<TxId, CWalletTx> walletEntry : mapWallet) {
         CWalletTx *pcoin = &walletEntry.second;
 
         if (!pcoin->IsTrusted()) {
             continue;
         }
 
         if (pcoin->IsImmatureCoinBase()) {
             continue;
         }
 
         int nDepth = pcoin->GetDepthInMainChain();
         if (nDepth < (pcoin->IsFromMe(ISMINE_ALL) ? 0 : 1)) {
             continue;
         }
 
         for (uint32_t i = 0; i < pcoin->tx->vout.size(); i++) {
             CTxDestination addr;
             if (!IsMine(pcoin->tx->vout[i])) {
                 continue;
             }
 
             if (!ExtractDestination(pcoin->tx->vout[i].scriptPubKey, addr)) {
                 continue;
             }
 
             Amount n = IsSpent(walletEntry.first, i)
                            ? Amount::zero()
                            : pcoin->tx->vout[i].nValue;
 
             if (!balances.count(addr)) {
                 balances[addr] = Amount::zero();
             }
             balances[addr] += n;
         }
     }
 
     return balances;
 }
 
 std::set<std::set<CTxDestination>> CWallet::GetAddressGroupings() {
     // mapWallet
     AssertLockHeld(cs_wallet);
     std::set<std::set<CTxDestination>> groupings;
     std::set<CTxDestination> grouping;
 
     for (std::pair<uint256, CWalletTx> walletEntry : mapWallet) {
         CWalletTx *pcoin = &walletEntry.second;
 
         if (pcoin->tx->vin.size() > 0) {
             bool any_mine = false;
             // Group all input addresses with each other.
             for (CTxIn txin : pcoin->tx->vin) {
                 CTxDestination address;
                 // If this input isn't mine, ignore it.
                 if (!IsMine(txin)) {
                     continue;
                 }
 
                 if (!ExtractDestination(mapWallet.at(txin.prevout.GetTxId())
                                             .tx->vout[txin.prevout.GetN()]
                                             .scriptPubKey,
                                         address)) {
                     continue;
                 }
 
                 grouping.insert(address);
                 any_mine = true;
             }
 
             // Group change with input addresses.
             if (any_mine) {
                 for (CTxOut txout : pcoin->tx->vout) {
                     if (IsChange(txout)) {
                         CTxDestination txoutAddr;
                         if (!ExtractDestination(txout.scriptPubKey,
                                                 txoutAddr)) {
                             continue;
                         }
 
                         grouping.insert(txoutAddr);
                     }
                 }
             }
 
             if (grouping.size() > 0) {
                 groupings.insert(grouping);
                 grouping.clear();
             }
         }
 
         // Group lone addrs by themselves.
         for (unsigned int i = 0; i < pcoin->tx->vout.size(); i++)
             if (IsMine(pcoin->tx->vout[i])) {
                 CTxDestination address;
                 if (!ExtractDestination(pcoin->tx->vout[i].scriptPubKey,
                                         address)) {
                     continue;
                 }
 
                 grouping.insert(address);
                 groupings.insert(grouping);
                 grouping.clear();
             }
     }
 
     // A set of pointers to groups of addresses.
     std::set<std::set<CTxDestination> *> uniqueGroupings;
     // Map addresses to the unique group containing it.
     std::map<CTxDestination, std::set<CTxDestination> *> setmap;
     for (std::set<CTxDestination> _grouping : groupings) {
         // Make a set of all the groups hit by this new group.
         std::set<std::set<CTxDestination> *> hits;
         std::map<CTxDestination, std::set<CTxDestination> *>::iterator it;
         for (CTxDestination address : _grouping) {
             if ((it = setmap.find(address)) != setmap.end()) {
                 hits.insert((*it).second);
             }
         }
 
         // Merge all hit groups into a new single group and delete old groups.
         std::set<CTxDestination> *merged =
             new std::set<CTxDestination>(_grouping);
         for (std::set<CTxDestination> *hit : hits) {
             merged->insert(hit->begin(), hit->end());
             uniqueGroupings.erase(hit);
             delete hit;
         }
         uniqueGroupings.insert(merged);
 
         // Update setmap.
         for (CTxDestination element : *merged) {
             setmap[element] = merged;
         }
     }
 
     std::set<std::set<CTxDestination>> ret;
     for (std::set<CTxDestination> *uniqueGrouping : uniqueGroupings) {
         ret.insert(*uniqueGrouping);
         delete uniqueGrouping;
     }
 
     return ret;
 }
 
 std::set<CTxDestination>
 CWallet::GetLabelAddresses(const std::string &label) const {
     LOCK(cs_wallet);
     std::set<CTxDestination> result;
     for (const std::pair<CTxDestination, CAddressBookData> &item :
          mapAddressBook) {
         const CTxDestination &address = item.first;
         const std::string &strName = item.second.name;
         if (strName == label) {
             result.insert(address);
         }
     }
 
     return result;
 }
 
 bool CReserveKey::GetReservedKey(CPubKey &pubkey, bool internal) {
     if (nIndex == -1) {
         CKeyPool keypool;
         pwallet->ReserveKeyFromKeyPool(nIndex, keypool, internal);
         if (nIndex == -1) {
             return false;
         }
 
         vchPubKey = keypool.vchPubKey;
         fInternal = keypool.fInternal;
     }
 
     assert(vchPubKey.IsValid());
     pubkey = vchPubKey;
     return true;
 }
 
 void CReserveKey::KeepKey() {
     if (nIndex != -1) {
         pwallet->KeepKey(nIndex);
     }
 
     nIndex = -1;
     vchPubKey = CPubKey();
 }
 
 void CReserveKey::ReturnKey() {
     if (nIndex != -1) {
         pwallet->ReturnKey(nIndex, fInternal, vchPubKey);
     }
     nIndex = -1;
     vchPubKey = CPubKey();
 }
 
 void CWallet::MarkReserveKeysAsUsed(int64_t keypool_id) {
     AssertLockHeld(cs_wallet);
     bool internal = setInternalKeyPool.count(keypool_id);
     if (!internal) {
         assert(setExternalKeyPool.count(keypool_id));
     }
 
     std::set<int64_t> *setKeyPool =
         internal ? &setInternalKeyPool : &setExternalKeyPool;
     auto it = setKeyPool->begin();
 
     CWalletDB walletdb(*dbw);
     while (it != std::end(*setKeyPool)) {
         const int64_t &index = *(it);
         if (index > keypool_id) {
             // set*KeyPool is ordered
             break;
         }
 
         CKeyPool keypool;
         if (walletdb.ReadPool(index, keypool)) {
             // TODO: This should be unnecessary
             m_pool_key_to_index.erase(keypool.vchPubKey.GetID());
         }
         LearnAllRelatedScripts(keypool.vchPubKey);
         walletdb.ErasePool(index);
         it = setKeyPool->erase(it);
     }
 }
 
 bool CWallet::HasUnusedKeys(size_t min_keys) const {
     return setExternalKeyPool.size() >= min_keys &&
            (setInternalKeyPool.size() >= min_keys ||
             !CanSupportFeature(FEATURE_HD_SPLIT));
 }
 
 void CWallet::GetScriptForMining(std::shared_ptr<CReserveScript> &script) {
     std::shared_ptr<CReserveKey> rKey = std::make_shared<CReserveKey>(this);
     CPubKey pubkey;
     if (!rKey->GetReservedKey(pubkey)) {
         return;
     }
 
     script = rKey;
     script->reserveScript = CScript() << ToByteVector(pubkey) << OP_CHECKSIG;
 }
 
 void CWallet::LockCoin(const COutPoint &output) {
     // setLockedCoins
     AssertLockHeld(cs_wallet);
     setLockedCoins.insert(output);
 }
 
 void CWallet::UnlockCoin(const COutPoint &output) {
     // setLockedCoins
     AssertLockHeld(cs_wallet);
     setLockedCoins.erase(output);
 }
 
 void CWallet::UnlockAllCoins() {
     // setLockedCoins
     AssertLockHeld(cs_wallet);
     setLockedCoins.clear();
 }
 
 bool CWallet::IsLockedCoin(const TxId &txid, uint32_t n) const {
     // setLockedCoins
     AssertLockHeld(cs_wallet);
     COutPoint outpt(txid, n);
 
     return setLockedCoins.count(outpt) > 0;
 }
 
 void CWallet::ListLockedCoins(std::vector<COutPoint> &vOutpts) const {
     // setLockedCoins
     AssertLockHeld(cs_wallet);
     for (COutPoint outpoint : setLockedCoins) {
         vOutpts.push_back(outpoint);
     }
 }
 
 /** @} */ // end of Actions
 
 void CWallet::GetKeyBirthTimes(
     std::map<CTxDestination, int64_t> &mapKeyBirth) const {
     // mapKeyMetadata
     AssertLockHeld(cs_wallet);
     mapKeyBirth.clear();
 
     // Get birth times for keys with metadata.
     for (const auto &entry : mapKeyMetadata) {
         if (entry.second.nCreateTime) {
             mapKeyBirth[entry.first] = entry.second.nCreateTime;
         }
     }
 
     // Map in which we'll infer heights of other keys the tip can be
     // reorganized; use a 144-block safety margin.
     CBlockIndex *pindexMax =
         chainActive[std::max(0, chainActive.Height() - 144)];
     std::map<CKeyID, CBlockIndex *> mapKeyFirstBlock;
     for (const CKeyID &keyid : GetKeys()) {
         if (mapKeyBirth.count(keyid) == 0) {
             mapKeyFirstBlock[keyid] = pindexMax;
         }
     }
 
     // If there are no such keys, we're done.
     if (mapKeyFirstBlock.empty()) {
         return;
     }
 
     // Find first block that affects those keys, if there are any left.
     std::vector<CKeyID> vAffected;
     for (const auto &entry : mapWallet) {
         // iterate over all wallet transactions...
         const CWalletTx &wtx = entry.second;
         CBlockIndex *pindex = LookupBlockIndex(wtx.hashBlock);
         if (pindex && chainActive.Contains(pindex)) {
             // ... which are already in a block
             int nHeight = pindex->nHeight;
             for (const CTxOut &txout : wtx.tx->vout) {
                 // Iterate over all their outputs...
                 CAffectedKeysVisitor(*this, vAffected)
                     .Process(txout.scriptPubKey);
                 for (const CKeyID &keyid : vAffected) {
                     // ... and all their affected keys.
                     std::map<CKeyID, CBlockIndex *>::iterator rit =
                         mapKeyFirstBlock.find(keyid);
                     if (rit != mapKeyFirstBlock.end() &&
                         nHeight < rit->second->nHeight) {
                         rit->second = pindex;
                     }
                 }
                 vAffected.clear();
             }
         }
     }
 
     // Extract block timestamps for those keys.
     for (const auto &entry : mapKeyFirstBlock) {
         // block times can be 2h off
         mapKeyBirth[entry.first] =
             entry.second->GetBlockTime() - TIMESTAMP_WINDOW;
     }
 }
 
 /**
  * Compute smart timestamp for a transaction being added to the wallet.
  *
  * Logic:
  * - If sending a transaction, assign its timestamp to the current time.
  * - If receiving a transaction outside a block, assign its timestamp to the
  *   current time.
  * - If receiving a block with a future timestamp, assign all its (not already
  *   known) transactions' timestamps to the current time.
  * - If receiving a block with a past timestamp, before the most recent known
  *   transaction (that we care about), assign all its (not already known)
  *   transactions' timestamps to the same timestamp as that most-recent-known
  *   transaction.
  * - If receiving a block with a past timestamp, but after the most recent known
  *   transaction, assign all its (not already known) transactions' timestamps to
  *   the block time.
  *
  * For more information see CWalletTx::nTimeSmart,
  * https://bitcointalk.org/?topic=54527, or
  * https://github.com/bitcoin/bitcoin/pull/1393.
  */
 unsigned int CWallet::ComputeTimeSmart(const CWalletTx &wtx) const {
     unsigned int nTimeSmart = wtx.nTimeReceived;
     if (!wtx.hashUnset()) {
         if (const CBlockIndex *pindex = LookupBlockIndex(wtx.hashBlock)) {
             int64_t latestNow = wtx.nTimeReceived;
             int64_t latestEntry = 0;
 
             // Tolerate times up to the last timestamp in the wallet not more
             // than 5 minutes into the future
             int64_t latestTolerated = latestNow + 300;
             const TxItems &txOrdered = wtxOrdered;
             for (auto it = txOrdered.rbegin(); it != txOrdered.rend(); ++it) {
                 CWalletTx *const pwtx = it->second.first;
                 if (pwtx == &wtx) {
                     continue;
                 }
                 CAccountingEntry *const pacentry = it->second.second;
                 int64_t nSmartTime;
                 if (pwtx) {
                     nSmartTime = pwtx->nTimeSmart;
                     if (!nSmartTime) {
                         nSmartTime = pwtx->nTimeReceived;
                     }
                 } else {
                     nSmartTime = pacentry->nTime;
                 }
                 if (nSmartTime <= latestTolerated) {
                     latestEntry = nSmartTime;
                     if (nSmartTime > latestNow) {
                         latestNow = nSmartTime;
                     }
                     break;
                 }
             }
 
             int64_t blocktime = pindex->GetBlockTime();
             nTimeSmart = std::max(latestEntry, std::min(blocktime, latestNow));
         } else {
             LogPrintf("%s: found %s in block %s not in index\n", __func__,
                       wtx.GetId().ToString(), wtx.hashBlock.ToString());
         }
     }
     return nTimeSmart;
 }
 
 bool CWallet::AddDestData(const CTxDestination &dest, const std::string &key,
                           const std::string &value) {
     if (boost::get<CNoDestination>(&dest)) {
         return false;
     }
 
     mapAddressBook[dest].destdata.insert(std::make_pair(key, value));
     return CWalletDB(*dbw).WriteDestData(dest, key, value);
 }
 
 bool CWallet::EraseDestData(const CTxDestination &dest,
                             const std::string &key) {
     if (!mapAddressBook[dest].destdata.erase(key)) {
         return false;
     }
 
     return CWalletDB(*dbw).EraseDestData(dest, key);
 }
 
 bool CWallet::LoadDestData(const CTxDestination &dest, const std::string &key,
                            const std::string &value) {
     mapAddressBook[dest].destdata.insert(std::make_pair(key, value));
     return true;
 }
 
 bool CWallet::GetDestData(const CTxDestination &dest, const std::string &key,
                           std::string *value) const {
     std::map<CTxDestination, CAddressBookData>::const_iterator i =
         mapAddressBook.find(dest);
     if (i != mapAddressBook.end()) {
         CAddressBookData::StringMap::const_iterator j =
             i->second.destdata.find(key);
         if (j != i->second.destdata.end()) {
             if (value) {
                 *value = j->second;
             }
 
             return true;
         }
     }
     return false;
 }
 
 std::vector<std::string>
 CWallet::GetDestValues(const std::string &prefix) const {
     LOCK(cs_wallet);
     std::vector<std::string> values;
     for (const auto &address : mapAddressBook) {
         for (const auto &data : address.second.destdata) {
             if (!data.first.compare(0, prefix.size(), prefix)) {
                 values.emplace_back(data.second);
             }
         }
     }
     return values;
 }
 
 CWallet *CWallet::CreateWalletFromFile(const CChainParams &chainParams,
                                        const std::string &name,
                                        const fs::path &path) {
     const std::string &walletFile = name;
 
     // Needed to restore wallet transaction meta data after -zapwallettxes
     std::vector<CWalletTx> vWtx;
 
     if (gArgs.GetBoolArg("-zapwallettxes", false)) {
         uiInterface.InitMessage(_("Zapping all transactions from wallet..."));
 
         std::unique_ptr<CWallet> tempWallet = std::make_unique<CWallet>(
             chainParams, name, CWalletDBWrapper::Create(path));
         DBErrors nZapWalletRet = tempWallet->ZapWalletTx(vWtx);
         if (nZapWalletRet != DBErrors::LOAD_OK) {
             InitError(
                 strprintf(_("Error loading %s: Wallet corrupted"), walletFile));
             return nullptr;
         }
     }
 
     uiInterface.InitMessage(_("Loading wallet..."));
 
     int64_t nStart = GetTimeMillis();
     bool fFirstRun = true;
     CWallet *walletInstance =
         new CWallet(chainParams, name, CWalletDBWrapper::Create(path));
     DBErrors nLoadWalletRet = walletInstance->LoadWallet(fFirstRun);
     if (nLoadWalletRet != DBErrors::LOAD_OK) {
         if (nLoadWalletRet == DBErrors::CORRUPT) {
             InitError(
                 strprintf(_("Error loading %s: Wallet corrupted"), walletFile));
             return nullptr;
         }
 
         if (nLoadWalletRet == DBErrors::NONCRITICAL_ERROR) {
             InitWarning(strprintf(
                 _("Error reading %s! All keys read correctly, but transaction "
                   "data"
                   " or address book entries might be missing or incorrect."),
                 walletFile));
         } else if (nLoadWalletRet == DBErrors::TOO_NEW) {
             InitError(strprintf(
                 _("Error loading %s: Wallet requires newer version of %s"),
                 walletFile, _(PACKAGE_NAME)));
             return nullptr;
         } else if (nLoadWalletRet == DBErrors::NEED_REWRITE) {
             InitError(strprintf(
                 _("Wallet needed to be rewritten: restart %s to complete"),
                 _(PACKAGE_NAME)));
             return nullptr;
         } else {
             InitError(strprintf(_("Error loading %s"), walletFile));
             return nullptr;
         }
     }
 
     if (gArgs.GetBoolArg("-upgradewallet", fFirstRun)) {
         int nMaxVersion = gArgs.GetArg("-upgradewallet", 0);
         // The -upgradewallet without argument case
         if (nMaxVersion == 0) {
             LogPrintf("Performing wallet upgrade to %i\n", FEATURE_LATEST);
             nMaxVersion = CLIENT_VERSION;
             // permanently upgrade the wallet immediately
             walletInstance->SetMinVersion(FEATURE_LATEST);
         } else {
             LogPrintf("Allowing wallet upgrade up to %i\n", nMaxVersion);
         }
 
         if (nMaxVersion < walletInstance->GetVersion()) {
             InitError(_("Cannot downgrade wallet"));
             return nullptr;
         }
 
         walletInstance->SetMaxVersion(nMaxVersion);
     }
 
     if (fFirstRun) {
         // Ensure this wallet.dat can only be opened by clients supporting
         // HD with chain split and expects no default key.
         walletInstance->SetMinVersion(FEATURE_NO_DEFAULT_KEY);
 
         // Generate a new master key.
         CPubKey masterPubKey = walletInstance->GenerateNewHDMasterKey();
         if (!walletInstance->SetHDMasterKey(masterPubKey)) {
             throw std::runtime_error(std::string(__func__) +
                                      ": Storing master key failed");
         }
 
         // Top up the keypool
         if (!walletInstance->TopUpKeyPool()) {
             InitError(_("Unable to generate initial keys") += "\n");
             return nullptr;
         }
 
         walletInstance->ChainStateFlushed(chainActive.GetLocator());
     } else if (gArgs.IsArgSet("-usehd")) {
         bool useHD = gArgs.GetBoolArg("-usehd", DEFAULT_USE_HD_WALLET);
         if (walletInstance->IsHDEnabled() && !useHD) {
             InitError(
                 strprintf(_("Error loading %s: You can't disable HD on an "
                             "already existing HD wallet"),
                           walletFile));
             return nullptr;
         }
 
         if (!walletInstance->IsHDEnabled() && useHD) {
             InitError(strprintf(_("Error loading %s: You can't enable HD on an "
                                   "already existing non-HD wallet or create "
                                   "new non-HD wallets."),
                                 walletFile));
             return nullptr;
         }
     }
 
     LogPrintf(" wallet      %15dms\n", GetTimeMillis() - nStart);
 
     // Try to top up keypool. No-op if the wallet is locked.
     walletInstance->TopUpKeyPool();
 
     LOCK(cs_main);
 
     CBlockIndex *pindexRescan = chainActive.Genesis();
     if (!gArgs.GetBoolArg("-rescan", false)) {
         CWalletDB walletdb(*walletInstance->dbw);
         CBlockLocator locator;
         if (walletdb.ReadBestBlock(locator)) {
             pindexRescan = FindForkInGlobalIndex(chainActive, locator);
         }
     }
 
     walletInstance->m_last_block_processed = chainActive.Tip();
     RegisterValidationInterface(walletInstance);
 
     if (chainActive.Tip() && chainActive.Tip() != pindexRescan) {
         // We can't rescan beyond non-pruned blocks, stop and throw an error.
         // This might happen if a user uses an old wallet within a pruned node
         // or if he ran -disablewallet for a longer time, then decided to
         // re-enable.
         if (fPruneMode) {
             CBlockIndex *block = chainActive.Tip();
             while (block && block->pprev && block->pprev->nStatus.hasData() &&
                    block->pprev->nTx > 0 && pindexRescan != block) {
                 block = block->pprev;
             }
 
             if (pindexRescan != block) {
                 InitError(_("Prune: last wallet synchronisation goes beyond "
                             "pruned data. You need to -reindex (download the "
                             "whole blockchain again in case of pruned node)"));
                 return nullptr;
             }
         }
 
         uiInterface.InitMessage(_("Rescanning..."));
         LogPrintf("Rescanning last %i blocks (from block %i)...\n",
                   chainActive.Height() - pindexRescan->nHeight,
                   pindexRescan->nHeight);
 
         // No need to read and scan block if block was created before our wallet
         // birthday (as adjusted for block time variability)
         while (pindexRescan && walletInstance->nTimeFirstKey &&
                (pindexRescan->GetBlockTime() <
                 (walletInstance->nTimeFirstKey - TIMESTAMP_WINDOW))) {
             pindexRescan = chainActive.Next(pindexRescan);
         }
 
         nStart = GetTimeMillis();
         {
             WalletRescanReserver reserver(walletInstance);
             if (!reserver.reserve()) {
                 InitError(
                     _("Failed to rescan the wallet during initialization"));
                 return nullptr;
             }
             walletInstance->ScanForWalletTransactions(pindexRescan, nullptr,
                                                       reserver, true);
         }
         LogPrintf(" rescan      %15dms\n", GetTimeMillis() - nStart);
         walletInstance->ChainStateFlushed(chainActive.GetLocator());
         walletInstance->dbw->IncrementUpdateCounter();
 
         // Restore wallet transaction metadata after -zapwallettxes=1
         if (gArgs.GetBoolArg("-zapwallettxes", false) &&
             gArgs.GetArg("-zapwallettxes", "1") != "2") {
             CWalletDB walletdb(*walletInstance->dbw);
 
             for (const CWalletTx &wtxOld : vWtx) {
                 const TxId txid = wtxOld.GetId();
                 std::map<TxId, CWalletTx>::iterator mi =
                     walletInstance->mapWallet.find(txid);
                 if (mi != walletInstance->mapWallet.end()) {
                     const CWalletTx *copyFrom = &wtxOld;
                     CWalletTx *copyTo = &mi->second;
                     copyTo->mapValue = copyFrom->mapValue;
                     copyTo->vOrderForm = copyFrom->vOrderForm;
                     copyTo->nTimeReceived = copyFrom->nTimeReceived;
                     copyTo->nTimeSmart = copyFrom->nTimeSmart;
                     copyTo->fFromMe = copyFrom->fFromMe;
                     copyTo->strFromAccount = copyFrom->strFromAccount;
                     copyTo->nOrderPos = copyFrom->nOrderPos;
                     walletdb.WriteTx(*copyTo);
                 }
             }
         }
     }
 
     walletInstance->SetBroadcastTransactions(
         gArgs.GetBoolArg("-walletbroadcast", DEFAULT_WALLETBROADCAST));
 
     LOCK(walletInstance->cs_wallet);
     LogPrintf("setKeyPool.size() = %u\n", walletInstance->GetKeyPoolSize());
     LogPrintf("mapWallet.size() = %u\n", walletInstance->mapWallet.size());
     LogPrintf("mapAddressBook.size() = %u\n",
               walletInstance->mapAddressBook.size());
 
     return walletInstance;
 }
 
 std::atomic<bool> CWallet::fFlushScheduled(false);
 
 void CWallet::postInitProcess(CScheduler &scheduler) {
     // Add wallet transactions that aren't already in a block to mempool.
     // Do this here as mempool requires genesis block to be loaded.
     ReacceptWalletTransactions();
 
     // Run a thread to flush wallet periodically.
     if (!CWallet::fFlushScheduled.exchange(true)) {
         scheduler.scheduleEvery(
             []() {
                 MaybeCompactWalletDB();
                 return true;
             },
             500);
     }
 }
 
 bool CWallet::BackupWallet(const std::string &strDest) {
     return dbw->Backup(strDest);
 }
 
 CKeyPool::CKeyPool() {
     nTime = GetTime();
     fInternal = false;
 }
 
 CKeyPool::CKeyPool(const CPubKey &vchPubKeyIn, bool internalIn) {
     nTime = GetTime();
     vchPubKey = vchPubKeyIn;
     fInternal = internalIn;
 }
 
 CWalletKey::CWalletKey(int64_t nExpires) {
     nTimeCreated = (nExpires ? GetTime() : 0);
     nTimeExpires = nExpires;
 }
 
 void CMerkleTx::SetMerkleBranch(const CBlockIndex *pindex, int posInBlock) {
     // Update the tx's hashBlock
     hashBlock = pindex->GetBlockHash();
 
     // Set the position of the transaction in the block.
     nIndex = posInBlock;
 }
 
 int CMerkleTx::GetDepthInMainChain(const CBlockIndex *&pindexRet) const {
     if (hashUnset()) {
         return 0;
     }
 
     AssertLockHeld(cs_main);
 
     // Find the block it claims to be in.
     CBlockIndex *pindex = LookupBlockIndex(hashBlock);
     if (!pindex || !chainActive.Contains(pindex)) {
         return 0;
     }
 
     pindexRet = pindex;
     return ((nIndex == -1) ? (-1) : 1) *
            (chainActive.Height() - pindex->nHeight + 1);
 }
 
 int CMerkleTx::GetBlocksToMaturity() const {
     if (!IsCoinBase()) {
         return 0;
     }
 
     return std::max(0, (COINBASE_MATURITY + 1) - GetDepthInMainChain());
 }
 
 bool CMerkleTx::IsImmatureCoinBase() const {
     // note GetBlocksToMaturity is 0 for non-coinbase tx
     return GetBlocksToMaturity() > 0;
 }
 
 bool CWalletTx::AcceptToMemoryPool(const Amount nAbsurdFee,
                                    CValidationState &state) {
     // We must set fInMempool here - while it will be re-set to true by the
     // entered-mempool callback, if we did not there would be a race where a
     // user could call sendmoney in a loop and hit spurious out of funds errors
     // because we think that the transaction they just generated's change is
     // unavailable as we're not yet aware its in mempool.
     bool ret = ::AcceptToMemoryPool(
         GetConfig(), g_mempool, state, tx, true /* fLimitFree */,
         nullptr /* pfMissingInputs */, false /* fOverrideMempoolLimit */,
         nAbsurdFee);
     fInMempool = ret;
     return ret;
 }
 
 static const std::string OUTPUT_TYPE_STRING_LEGACY = "legacy";
 
 OutputType ParseOutputType(const std::string &type, OutputType default_type) {
     if (type.empty()) {
         return default_type;
     } else if (type == OUTPUT_TYPE_STRING_LEGACY) {
         return OutputType::LEGACY;
     } else {
         return OutputType::NONE;
     }
 }
 
 const std::string &FormatOutputType(OutputType type) {
     switch (type) {
         case OutputType::LEGACY:
             return OUTPUT_TYPE_STRING_LEGACY;
         default:
             assert(false);
     }
 }
 
 void CWallet::LearnRelatedScripts(const CPubKey &key, OutputType type) {
     // Nothing to do...
 }
 
 void CWallet::LearnAllRelatedScripts(const CPubKey &key) {
     // Nothing to do...
 }
 
 CTxDestination GetDestinationForKey(const CPubKey &key, OutputType type) {
     switch (type) {
         case OutputType::LEGACY:
             return key.GetID();
         default:
             assert(false);
     }
 }
 
 std::vector<CTxDestination> GetAllDestinationsForKey(const CPubKey &key) {
     return std::vector<CTxDestination>{key.GetID()};
 }
 
 CTxDestination CWallet::AddAndGetDestinationForScript(const CScript &script,
                                                       OutputType type) {
     // Note that scripts over 520 bytes are not yet supported.
     switch (type) {
         case OutputType::LEGACY:
             return CScriptID(script);
         default:
             assert(false);
     }
 }
diff --git a/src/wallet/wallet.h b/src/wallet/wallet.h
index b51123507..1e4cc8ce5 100644
--- a/src/wallet/wallet.h
+++ b/src/wallet/wallet.h
@@ -1,1392 +1,1390 @@
 // Copyright (c) 2009-2010 Satoshi Nakamoto
 // Copyright (c) 2009-2016 The Bitcoin Core developers
 // Copyright (c) 2018 The Bitcoin developers
 // Distributed under the MIT software license, see the accompanying
 // file COPYING or http://www.opensource.org/licenses/mit-license.php.
 
 #ifndef BITCOIN_WALLET_WALLET_H
 #define BITCOIN_WALLET_WALLET_H
 
 #include <amount.h>
 #include <script/ismine.h>
 #include <script/sign.h>
 #include <streams.h>
 #include <tinyformat.h>
 #include <ui_interface.h>
 #include <util.h>
 #include <utilstrencodings.h>
 #include <validationinterface.h>
 #include <wallet/crypter.h>
 #include <wallet/rpcwallet.h>
 #include <wallet/walletdb.h>
 
 #include <algorithm>
 #include <atomic>
 #include <cstdint>
 #include <map>
 #include <set>
 #include <stdexcept>
 #include <string>
 #include <utility>
 #include <vector>
 
 typedef CWallet *CWalletRef;
 extern std::vector<CWalletRef> vpwallets;
 
 /**
  * Settings
  */
 extern CFeeRate payTxFee;
 extern bool bSpendZeroConfChange;
 
 static const unsigned int DEFAULT_KEYPOOL_SIZE = 1000;
 //! -paytxfee default
 static const Amount DEFAULT_TRANSACTION_FEE = Amount::zero();
 //! -fallbackfee default
 static const Amount DEFAULT_FALLBACK_FEE(20000 * SATOSHI);
 //! minimum recommended increment for BIP 125 replacement txs
 static const Amount WALLET_INCREMENTAL_RELAY_FEE(5000 * SATOSHI);
 //! target minimum change amount
 static const Amount MIN_CHANGE = CENT;
 //! final minimum change amount after paying for fees
 static const Amount MIN_FINAL_CHANGE = MIN_CHANGE / 2;
 //! Default for -spendzeroconfchange
 static const bool DEFAULT_SPEND_ZEROCONF_CHANGE = true;
 //! Default for -walletrejectlongchains
 static const bool DEFAULT_WALLET_REJECT_LONG_CHAINS = false;
 //! Largest (in bytes) free transaction we're willing to create
 static const unsigned int MAX_FREE_TRANSACTION_CREATE_SIZE = 1000;
 static const bool DEFAULT_WALLETBROADCAST = true;
 static const bool DEFAULT_DISABLE_WALLET = false;
 //! if set, all keys will be derived by using BIP32
 static const bool DEFAULT_USE_HD_WALLET = true;
 
-extern const char *DEFAULT_WALLET_DAT;
-
 static const int64_t TIMESTAMP_MIN = 0;
 
 class CBlockIndex;
 class CChainParams;
 class CCoinControl;
 class COutput;
 class CReserveKey;
 class CScript;
 class CScheduler;
 class CTxMemPool;
 class CWalletTx;
 
 /** (client) version numbers for particular wallet features */
 enum WalletFeature {
     // the earliest version new wallets supports (only useful for getinfo's
     // clientversion output)
     FEATURE_BASE = 10500,
 
     // wallet encryption
     FEATURE_WALLETCRYPT = 40000,
     // compressed public keys
     FEATURE_COMPRPUBKEY = 60000,
 
     // Hierarchical key derivation after BIP32 (HD Wallet)
     FEATURE_HD = 130000,
 
     // Wallet with HD chain split (change outputs will use m/0'/1'/k)
     FEATURE_HD_SPLIT = 160300,
 
     // Wallet without a default key written
     FEATURE_NO_DEFAULT_KEY = 190700,
 
     // HD is optional, use FEATURE_COMPRPUBKEY as latest version
     FEATURE_LATEST = FEATURE_COMPRPUBKEY,
 };
 
 enum class OutputType {
     NONE,
     LEGACY,
 
     DEFAULT = LEGACY,
 };
 
 extern OutputType g_address_type;
 extern OutputType g_change_type;
 
 /** A key pool entry */
 class CKeyPool {
 public:
     int64_t nTime;
     CPubKey vchPubKey;
     bool fInternal; // for change outputs
 
     CKeyPool();
     CKeyPool(const CPubKey &vchPubKeyIn, bool internalIn);
 
     ADD_SERIALIZE_METHODS;
 
     template <typename Stream, typename Operation>
     inline void SerializationOp(Stream &s, Operation ser_action) {
         int nVersion = s.GetVersion();
         if (!(s.GetType() & SER_GETHASH)) {
             READWRITE(nVersion);
         }
 
         READWRITE(nTime);
         READWRITE(vchPubKey);
         if (ser_action.ForRead()) {
             try {
                 READWRITE(fInternal);
             } catch (std::ios_base::failure &) {
                 /**
                  * flag as external address if we can't read the internal
                  * boolean
                  * (this will be the case for any wallet before the HD chain
                  * split version)
                  */
                 fInternal = false;
             }
         } else {
             READWRITE(fInternal);
         }
     }
 };
 
 /** Address book data */
 class CAddressBookData {
 public:
     std::string name;
     std::string purpose;
 
     CAddressBookData() : purpose("unknown") {}
 
     typedef std::map<std::string, std::string> StringMap;
     StringMap destdata;
 };
 
 struct CRecipient {
     CScript scriptPubKey;
     Amount nAmount;
     bool fSubtractFeeFromAmount;
 };
 
 typedef std::map<std::string, std::string> mapValue_t;
 
 static inline void ReadOrderPos(int64_t &nOrderPos, mapValue_t &mapValue) {
     if (!mapValue.count("n")) {
         // TODO: calculate elsewhere
         nOrderPos = -1;
         return;
     }
 
     nOrderPos = atoi64(mapValue["n"].c_str());
 }
 
 static inline void WriteOrderPos(const int64_t &nOrderPos,
                                  mapValue_t &mapValue) {
     if (nOrderPos == -1) return;
     mapValue["n"] = i64tostr(nOrderPos);
 }
 
 struct COutputEntry {
     CTxDestination destination;
     Amount amount;
     int vout;
 };
 
 /** A transaction with a merkle branch linking it to the block chain. */
 class CMerkleTx {
 private:
     /** Constant used in hashBlock to indicate tx has been abandoned */
     static const uint256 ABANDON_HASH;
 
 public:
     CTransactionRef tx;
     uint256 hashBlock;
 
     /**
      * An nIndex == -1 means that hashBlock (in nonzero) refers to the earliest
      * block in the chain we know this or any in-wallet dependency conflicts
      * with. Older clients interpret nIndex == -1 as unconfirmed for backward
      * compatibility.
      */
     int nIndex;
 
     CMerkleTx() {
         SetTx(MakeTransactionRef());
         Init();
     }
 
     explicit CMerkleTx(CTransactionRef arg) {
         SetTx(std::move(arg));
         Init();
     }
 
     void Init() {
         hashBlock = uint256();
         nIndex = -1;
     }
 
     void SetTx(CTransactionRef arg) { tx = std::move(arg); }
 
     ADD_SERIALIZE_METHODS;
 
     template <typename Stream, typename Operation>
     inline void SerializationOp(Stream &s, Operation ser_action) {
         // For compatibility with older versions.
         std::vector<uint256> vMerkleBranch;
         READWRITE(tx);
         READWRITE(hashBlock);
         READWRITE(vMerkleBranch);
         READWRITE(nIndex);
     }
 
     void SetMerkleBranch(const CBlockIndex *pIndex, int posInBlock);
 
     /**
      * Return depth of transaction in blockchain:
      * <0  : conflicts with a transaction this deep in the blockchain
      *  0  : in memory pool, waiting to be included in a block
      * >=1 : this many blocks deep in the main chain
      */
     int GetDepthInMainChain(const CBlockIndex *&pindexRet) const;
     int GetDepthInMainChain() const {
         const CBlockIndex *pindexRet;
         return GetDepthInMainChain(pindexRet);
     }
     bool IsInMainChain() const {
         const CBlockIndex *pindexRet;
         return GetDepthInMainChain(pindexRet) > 0;
     }
     /**
      * @return number of blocks to maturity for this transaction:
      *  0 : is not a coinbase transaction, or is a mature coinbase transaction
      * >0 : is a coinbase transaction which matures in this many blocks
      */
     int GetBlocksToMaturity() const;
     bool hashUnset() const {
         return (hashBlock.IsNull() || hashBlock == ABANDON_HASH);
     }
     bool isAbandoned() const { return (hashBlock == ABANDON_HASH); }
     void setAbandoned() { hashBlock = ABANDON_HASH; }
 
     TxId GetId() const { return tx->GetId(); }
     bool IsCoinBase() const { return tx->IsCoinBase(); }
     bool IsImmatureCoinBase() const;
 };
 
 /**
  * A transaction with a bunch of additional info that only the owner cares
  * about. It includes any unrecorded transactions needed to link it back to the
  * block chain.
  */
 class CWalletTx : public CMerkleTx {
 private:
     const CWallet *pwallet;
 
 public:
     /**
      * Key/value map with information about the transaction.
      *
      * The following keys can be read and written through the map and are
      * serialized in the wallet database:
      *
      *     "comment", "to"   - comment strings provided to sendtoaddress,
      *                         sendfrom, sendmany wallet RPCs
      *     "replaces_txid"   - txid (as HexStr) of transaction replaced by
      *                         bumpfee on transaction created by bumpfee
      *     "replaced_by_txid" - txid (as HexStr) of transaction created by
      *                         bumpfee on transaction replaced by bumpfee
      *     "from", "message" - obsolete fields that could be set in UI prior to
      *                         2011 (removed in commit 4d9b223)
      *
      * The following keys are serialized in the wallet database, but shouldn't
      * be read or written through the map (they will be temporarily added and
      * removed from the map during serialization):
      *
      *     "fromaccount"     - serialized strFromAccount value
      *     "n"               - serialized nOrderPos value
      *     "timesmart"       - serialized nTimeSmart value
      *     "spent"           - serialized vfSpent value that existed prior to
      *                         2014 (removed in commit 93a18a3)
      */
     mapValue_t mapValue;
     std::vector<std::pair<std::string, std::string>> vOrderForm;
     unsigned int fTimeReceivedIsTxTime;
     //!< time received by this node
     unsigned int nTimeReceived;
     /**
      * Stable timestamp that never changes, and reflects the order a transaction
      * was added to the wallet. Timestamp is based on the block time for a
      * transaction added as part of a block, or else the time when the
      * transaction was received if it wasn't part of a block, with the timestamp
      * adjusted in both cases so timestamp order matches the order transactions
      * were added to the wallet. More details can be found in
      * CWallet::ComputeTimeSmart().
      */
     unsigned int nTimeSmart;
     /**
      * From me flag is set to 1 for transactions that were created by the wallet
      * on this bitcoin node, and set to 0 for transactions that were created
      * externally and came in through the network or sendrawtransaction RPC.
      */
     char fFromMe;
     std::string strFromAccount;
     //!< position in ordered transaction list
     int64_t nOrderPos;
 
     // memory only
     mutable bool fDebitCached;
     mutable bool fCreditCached;
     mutable bool fImmatureCreditCached;
     mutable bool fAvailableCreditCached;
     mutable bool fWatchDebitCached;
     mutable bool fWatchCreditCached;
     mutable bool fImmatureWatchCreditCached;
     mutable bool fAvailableWatchCreditCached;
     mutable bool fChangeCached;
     mutable bool fInMempool;
     mutable Amount nDebitCached;
     mutable Amount nCreditCached;
     mutable Amount nImmatureCreditCached;
     mutable Amount nAvailableCreditCached;
     mutable Amount nWatchDebitCached;
     mutable Amount nWatchCreditCached;
     mutable Amount nImmatureWatchCreditCached;
     mutable Amount nAvailableWatchCreditCached;
     mutable Amount nChangeCached;
 
     CWalletTx(const CWallet *pwalletIn, CTransactionRef arg)
         : CMerkleTx(std::move(arg)) {
         Init(pwalletIn);
     }
 
     void Init(const CWallet *pwalletIn) {
         pwallet = pwalletIn;
         mapValue.clear();
         vOrderForm.clear();
         fTimeReceivedIsTxTime = false;
         nTimeReceived = 0;
         nTimeSmart = 0;
         fFromMe = false;
         strFromAccount.clear();
         fDebitCached = false;
         fCreditCached = false;
         fImmatureCreditCached = false;
         fAvailableCreditCached = false;
         fWatchDebitCached = false;
         fWatchCreditCached = false;
         fImmatureWatchCreditCached = false;
         fAvailableWatchCreditCached = false;
         fChangeCached = false;
         fInMempool = false;
         nDebitCached = Amount::zero();
         nCreditCached = Amount::zero();
         nImmatureCreditCached = Amount::zero();
         nAvailableCreditCached = Amount::zero();
         nWatchDebitCached = Amount::zero();
         nWatchCreditCached = Amount::zero();
         nAvailableWatchCreditCached = Amount::zero();
         nImmatureWatchCreditCached = Amount::zero();
         nChangeCached = Amount::zero();
         nOrderPos = -1;
     }
 
     template <typename Stream> void Serialize(Stream &s) const {
         char fSpent = false;
         mapValue_t mapValueCopy = mapValue;
 
         mapValueCopy["fromaccount"] = strFromAccount;
         WriteOrderPos(nOrderPos, mapValueCopy);
         if (nTimeSmart) {
             mapValueCopy["timesmart"] = strprintf("%u", nTimeSmart);
         }
 
         s << static_cast<const CMerkleTx &>(*this);
         //!< Used to be vtxPrev
         std::vector<CMerkleTx> vUnused;
         s << vUnused << mapValueCopy << vOrderForm << fTimeReceivedIsTxTime
           << nTimeReceived << fFromMe << fSpent;
     }
 
     template <typename Stream> void Unserialize(Stream &s) {
         Init(nullptr);
         char fSpent;
 
         s >> static_cast<CMerkleTx &>(*this);
         //!< Used to be vtxPrev
         std::vector<CMerkleTx> vUnused;
         s >> vUnused >> mapValue >> vOrderForm >> fTimeReceivedIsTxTime >>
             nTimeReceived >> fFromMe >> fSpent;
 
         strFromAccount = std::move(mapValue["fromaccount"]);
         ReadOrderPos(nOrderPos, mapValue);
         nTimeSmart = mapValue.count("timesmart")
                          ? (unsigned int)atoi64(mapValue["timesmart"])
                          : 0;
 
         mapValue.erase("fromaccount");
         mapValue.erase("spent");
         mapValue.erase("n");
         mapValue.erase("timesmart");
     }
 
     //! make sure balances are recalculated
     void MarkDirty() {
         fCreditCached = false;
         fAvailableCreditCached = false;
         fImmatureCreditCached = false;
         fWatchDebitCached = false;
         fWatchCreditCached = false;
         fAvailableWatchCreditCached = false;
         fImmatureWatchCreditCached = false;
         fDebitCached = false;
         fChangeCached = false;
     }
 
     void BindWallet(CWallet *pwalletIn) {
         pwallet = pwalletIn;
         MarkDirty();
     }
 
     //! filter decides which addresses will count towards the debit
     Amount GetDebit(const isminefilter &filter) const;
     Amount GetCredit(const isminefilter &filter) const;
     Amount GetImmatureCredit(bool fUseCache = true) const;
     Amount GetAvailableCredit(bool fUseCache = true) const;
     Amount GetImmatureWatchOnlyCredit(const bool fUseCache = true) const;
     Amount GetAvailableWatchOnlyCredit(const bool fUseCache = true) const;
     Amount GetChange() const;
 
     void GetAmounts(std::list<COutputEntry> &listReceived,
                     std::list<COutputEntry> &listSent, Amount &nFee,
                     std::string &strSentAccount,
                     const isminefilter &filter) const;
 
     bool IsFromMe(const isminefilter &filter) const {
         return GetDebit(filter) > Amount::zero();
     }
 
     // True if only scriptSigs are different
     bool IsEquivalentTo(const CWalletTx &tx) const;
 
     bool InMempool() const;
     bool IsTrusted() const;
 
     int64_t GetTxTime() const;
     int GetRequestCount() const;
 
     // RelayWalletTransaction may only be called if fBroadcastTransactions!
     bool RelayWalletTransaction(CConnman *connman);
 
     /**
      * Pass this transaction to the mempool. Fails if absolute fee exceeds
      * absurd fee.
      */
     bool AcceptToMemoryPool(const Amount nAbsurdFee, CValidationState &state);
 
     std::set<TxId> GetConflicts() const;
 };
 
 class CInputCoin {
 public:
     CInputCoin(const CWalletTx *walletTx, unsigned int i) : wtx(walletTx) {
         if (!walletTx) {
             throw std::invalid_argument("walletTx should not be null");
         }
         if (i >= walletTx->tx->vout.size()) {
             throw std::out_of_range("The output index is out of range");
         }
 
         outpoint = COutPoint(walletTx->GetId(), i);
         txout = walletTx->tx->vout[i];
     }
 
     COutPoint outpoint;
     CTxOut txout;
     const CWalletTx *wtx;
 
     bool operator<(const CInputCoin &rhs) const {
         return outpoint < rhs.outpoint;
     }
 
     bool operator!=(const CInputCoin &rhs) const {
         return outpoint != rhs.outpoint;
     }
 
     bool operator==(const CInputCoin &rhs) const {
         return outpoint == rhs.outpoint;
     }
 };
 
 class COutput {
 public:
     const CWalletTx *tx;
     int i;
     int nDepth;
 
     /** Whether we have the private keys to spend this output */
     bool fSpendable;
 
     /** Whether we know how to spend this output, ignoring the lack of keys */
     bool fSolvable;
 
     /**
      * Whether this output is considered safe to spend. Unconfirmed transactions
      * from outside keys are considered unsafe and will not be used to fund new
      * spending transactions.
      */
     bool fSafe;
 
     COutput(const CWalletTx *txIn, int iIn, int nDepthIn, bool fSpendableIn,
             bool fSolvableIn, bool fSafeIn) {
         tx = txIn;
         i = iIn;
         nDepth = nDepthIn;
         fSpendable = fSpendableIn;
         fSolvable = fSolvableIn;
         fSafe = fSafeIn;
     }
 
     std::string ToString() const;
 };
 
 /** Private key that includes an expiration date in case it never gets used. */
 class CWalletKey {
 public:
     CPrivKey vchPrivKey;
     int64_t nTimeCreated;
     int64_t nTimeExpires;
     std::string strComment;
     //! todo: add something to note what created it (user, getnewaddress,
     //! change) maybe should have a map<string, string> property map
 
     explicit CWalletKey(int64_t nExpires = 0);
 
     ADD_SERIALIZE_METHODS;
 
     template <typename Stream, typename Operation>
     inline void SerializationOp(Stream &s, Operation ser_action) {
         int nVersion = s.GetVersion();
         if (!(s.GetType() & SER_GETHASH)) READWRITE(nVersion);
         READWRITE(vchPrivKey);
         READWRITE(nTimeCreated);
         READWRITE(nTimeExpires);
         READWRITE(LIMITED_STRING(strComment, 65536));
     }
 };
 
 /**
  * Internal transfers.
  * Database key is acentry<account><counter>.
  */
 class CAccountingEntry {
 public:
     std::string strAccount;
     Amount nCreditDebit;
     int64_t nTime;
     std::string strOtherAccount;
     std::string strComment;
     mapValue_t mapValue;
     //!< position in ordered transaction list
     int64_t nOrderPos;
     uint64_t nEntryNo;
 
     CAccountingEntry() { SetNull(); }
 
     void SetNull() {
         nCreditDebit = Amount::zero();
         nTime = 0;
         strAccount.clear();
         strOtherAccount.clear();
         strComment.clear();
         nOrderPos = -1;
         nEntryNo = 0;
     }
 
     template <typename Stream> void Serialize(Stream &s) const {
         int nVersion = s.GetVersion();
         if (!(s.GetType() & SER_GETHASH)) {
             s << nVersion;
         }
         //! Note: strAccount is serialized as part of the key, not here.
         s << nCreditDebit << nTime << strOtherAccount;
 
         mapValue_t mapValueCopy = mapValue;
         WriteOrderPos(nOrderPos, mapValueCopy);
 
         std::string strCommentCopy = strComment;
         if (!mapValueCopy.empty() || !_ssExtra.empty()) {
             CDataStream ss(s.GetType(), s.GetVersion());
             ss.insert(ss.begin(), '\0');
             ss << mapValueCopy;
             ss.insert(ss.end(), _ssExtra.begin(), _ssExtra.end());
             strCommentCopy.append(ss.str());
         }
         s << strCommentCopy;
     }
 
     template <typename Stream> void Unserialize(Stream &s) {
         int nVersion = s.GetVersion();
         if (!(s.GetType() & SER_GETHASH)) {
             s >> nVersion;
         }
         //! Note: strAccount is serialized as part of the key, not here.
         s >> nCreditDebit >> nTime >> LIMITED_STRING(strOtherAccount, 65536) >>
             LIMITED_STRING(strComment, 65536);
 
         size_t nSepPos = strComment.find("\0", 0, 1);
         mapValue.clear();
         if (std::string::npos != nSepPos) {
             CDataStream ss(std::vector<char>(strComment.begin() + nSepPos + 1,
                                              strComment.end()),
                            s.GetType(), s.GetVersion());
             ss >> mapValue;
             _ssExtra = std::vector<char>(ss.begin(), ss.end());
         }
         ReadOrderPos(nOrderPos, mapValue);
         if (std::string::npos != nSepPos) {
             strComment.erase(nSepPos);
         }
 
         mapValue.erase("n");
     }
 
 private:
     std::vector<char> _ssExtra;
 };
 
 // forward declarations for ScanForWalletTransactions/RescanFromTime
 class WalletRescanReserver;
 /**
  * A CWallet is an extension of a keystore, which also maintains a set of
  * transactions and balances, and provides the ability to create new
  * transactions.
  */
 class CWallet final : public CCryptoKeyStore, public CValidationInterface {
 private:
     static std::atomic<bool> fFlushScheduled;
     std::atomic<bool> fAbortRescan;
     // controlled by WalletRescanReserver
     std::atomic<bool> fScanningWallet;
     std::mutex mutexScanning;
     friend class WalletRescanReserver;
 
     /**
      * Select a set of coins such that nValueRet >= nTargetValue and at least
      * all coins from coinControl are selected; Never select unconfirmed coins
      * if they are not ours.
      */
     bool SelectCoins(const std::vector<COutput> &vAvailableCoins,
                      const Amount nTargetValue,
                      std::set<CInputCoin> &setCoinsRet, Amount &nValueRet,
                      const CCoinControl *coinControl = nullptr) const;
 
     CWalletDB *pwalletdbEncryption;
 
     //! the current wallet version: clients below this version are not able to
     //! load the wallet
     int nWalletVersion;
 
     //! the maximum wallet format version: memory-only variable that specifies
     //! to what version this wallet may be upgraded
     int nWalletMaxVersion;
 
     int64_t nNextResend;
     int64_t nLastResend;
     bool fBroadcastTransactions;
 
     /**
      * Used to keep track of spent outpoints, and detect and report conflicts
      * (double-spends or mutated transactions where the mutant gets mined).
      */
     typedef std::multimap<COutPoint, TxId> TxSpends;
     TxSpends mapTxSpends;
     void AddToSpends(const COutPoint &outpoint, const TxId &wtxid);
     void AddToSpends(const TxId &wtxid);
 
     /**
      * Mark a transaction (and its in-wallet descendants) as conflicting with a
      * particular block.
      */
     void MarkConflicted(const uint256 &hashBlock, const TxId &txid);
 
     void SyncMetaData(std::pair<TxSpends::iterator, TxSpends::iterator>);
 
     /**
      * Used by TransactionAddedToMemorypool/BlockConnected/Disconnected.
      * Should be called with pindexBlock and posInBlock if this is for a
      * transaction that is included in a block.
      */
     void SyncTransaction(const CTransactionRef &tx,
                          const CBlockIndex *pindex = nullptr,
                          int posInBlock = 0);
 
     /* the HD chain data model (external chain counters) */
     CHDChain hdChain;
 
     /* HD derive new child key (on internal or external chain) */
     void DeriveNewChildKey(CWalletDB &walletdb, CKeyMetadata &metadata,
                            CKey &secret, bool internal = false);
 
     std::set<int64_t> setInternalKeyPool;
     std::set<int64_t> setExternalKeyPool;
     int64_t m_max_keypool_index;
     std::map<CKeyID, int64_t> m_pool_key_to_index;
 
     int64_t nTimeFirstKey;
 
     /**
      * Private version of AddWatchOnly method which does not accept a timestamp,
      * and which will reset the wallet's nTimeFirstKey value to 1 if the watch
      * key did not previously have a timestamp associated with it. Because this
      * is an inherited virtual method, it is accessible despite being marked
      * private, but it is marked private anyway to encourage use of the other
      * AddWatchOnly which accepts a timestamp and sets nTimeFirstKey more
      * intelligently for more efficient rescans.
      */
     bool AddWatchOnly(const CScript &dest) override;
 
     /**
      * Wallet filename from wallet=<path> command line or config option.
      * Used in debug logs and to send RPCs to the right wallet instance when
      * more than one wallet is loaded.
      */
     std::string m_name;
 
     /** Internal database handle. */
     std::unique_ptr<CWalletDBWrapper> dbw;
 
     /**
      * The following is used to keep track of how far behind the wallet is
      * from the chain sync, and to allow clients to block on us being caught up.
      *
      * Note that this is *not* how far we've processed, we may need some rescan
      * to have seen all transactions in the chain, but is only used to track
      * live BlockConnected callbacks.
      *
      * Protected by cs_main (see BlockUntilSyncedToCurrentChain)
      */
     const CBlockIndex *m_last_block_processed;
 
 public:
     const CChainParams &chainParams;
     /*
      * Main wallet lock.
      * This lock protects all the fields added by CWallet.
      */
     mutable CCriticalSection cs_wallet;
 
     /**
      * Get database handle used by this wallet. Ideally this function would not
      * be necessary.
      */
     CWalletDBWrapper &GetDBHandle() { return *dbw; }
 
     /**
      * Get a name for this wallet for logging/debugging purposes.
      */
     std::string GetName() const { return m_name; }
 
     void LoadKeyPool(int64_t nIndex, const CKeyPool &keypool);
 
     // Map from Key ID to key metadata.
     std::map<CKeyID, CKeyMetadata> mapKeyMetadata;
 
     // Map from Script ID to key metadata (for watch-only keys).
     std::map<CScriptID, CKeyMetadata> m_script_metadata;
 
     typedef std::map<unsigned int, CMasterKey> MasterKeyMap;
     MasterKeyMap mapMasterKeys;
     unsigned int nMasterKeyMaxID;
 
     /** Construct wallet with specified name and database implementation. */
     CWallet(const CChainParams &chainParamsIn, std::string name,
             std::unique_ptr<CWalletDBWrapper> dbw_in)
         : m_name(std::move(name)), dbw(std::move(dbw_in)),
           chainParams(chainParamsIn) {
         SetNull();
     }
 
     ~CWallet() {
         delete pwalletdbEncryption;
         pwalletdbEncryption = nullptr;
     }
 
     void SetNull() {
         nWalletVersion = FEATURE_BASE;
         nWalletMaxVersion = FEATURE_BASE;
         nMasterKeyMaxID = 0;
         pwalletdbEncryption = nullptr;
         nOrderPosNext = 0;
         nAccountingEntryNumber = 0;
         nNextResend = 0;
         nLastResend = 0;
         m_max_keypool_index = 0;
         nTimeFirstKey = 0;
         fBroadcastTransactions = false;
         fAbortRescan = false;
         fScanningWallet = false;
         nRelockTime = 0;
     }
 
     std::map<TxId, CWalletTx> mapWallet;
     std::list<CAccountingEntry> laccentries;
 
     typedef std::pair<CWalletTx *, CAccountingEntry *> TxPair;
     typedef std::multimap<int64_t, TxPair> TxItems;
     TxItems wtxOrdered;
 
     int64_t nOrderPosNext;
     uint64_t nAccountingEntryNumber;
     std::map<uint256, int> mapRequestCount;
 
     std::map<CTxDestination, CAddressBookData> mapAddressBook;
 
     std::set<COutPoint> setLockedCoins;
 
     const CWalletTx *GetWalletTx(const TxId &txid) const;
 
     //! check whether we are allowed to upgrade (or already support) to the
     //! named feature
     bool CanSupportFeature(enum WalletFeature wf) const {
         AssertLockHeld(cs_wallet);
         return nWalletMaxVersion >= wf;
     }
 
     /**
      * populate vCoins with vector of available COutputs.
      */
     void AvailableCoins(std::vector<COutput> &vCoins, bool fOnlySafe = true,
                         const CCoinControl *coinControl = nullptr,
                         const Amount nMinimumAmount = SATOSHI,
                         const Amount nMaximumAmount = MAX_MONEY,
                         const Amount nMinimumSumAmount = MAX_MONEY,
                         const uint64_t nMaximumCount = 0,
                         const int nMinDepth = 0,
                         const int nMaxDepth = 9999999) const;
 
     /**
      * Return list of available coins and locked coins grouped by non-change
      * output address.
      */
     std::map<CTxDestination, std::vector<COutput>> ListCoins() const;
 
     /**
      * Find non-change parent output.
      */
     const CTxOut &FindNonChangeParentOutput(const CTransaction &tx,
                                             int output) const;
 
     /**
      * Shuffle and select coins until nTargetValue is reached while avoiding
      * small change; This method is stochastic for some inputs and upon
      * completion the coin set and corresponding actual target value is
      * assembled.
      */
     bool SelectCoinsMinConf(const Amount nTargetValue, int nConfMine,
                             int nConfTheirs, uint64_t nMaxAncestors,
                             std::vector<COutput> vCoins,
                             std::set<CInputCoin> &setCoinsRet,
                             Amount &nValueRet) const;
 
     bool IsSpent(const TxId &txid, uint32_t n) const;
 
     bool IsLockedCoin(const TxId &txid, uint32_t n) const;
     void LockCoin(const COutPoint &output);
     void UnlockCoin(const COutPoint &output);
     void UnlockAllCoins();
     void ListLockedCoins(std::vector<COutPoint> &vOutpts) const;
 
     /*
      * Rescan abort properties
      */
     void AbortRescan() { fAbortRescan = true; }
     bool IsAbortingRescan() { return fAbortRescan; }
     bool IsScanning() { return fScanningWallet; }
 
     /**
      * keystore implementation
      * Generate a new key
      */
     CPubKey GenerateNewKey(CWalletDB &walletdb, bool internal = false);
     //! Adds a key to the store, and saves it to disk.
     bool AddKeyPubKey(const CKey &key, const CPubKey &pubkey) override;
     bool AddKeyPubKeyWithDB(CWalletDB &walletdb, const CKey &key,
                             const CPubKey &pubkey);
     //! Adds a key to the store, without saving it to disk (used by LoadWallet)
     bool LoadKey(const CKey &key, const CPubKey &pubkey) {
         return CCryptoKeyStore::AddKeyPubKey(key, pubkey);
     }
 
     //! Load metadata (used by LoadWallet)
     bool LoadKeyMetadata(const CKeyID &keyID, const CKeyMetadata &metadata);
     bool LoadScriptMetadata(const CScriptID &script_id,
                             const CKeyMetadata &metadata);
 
     bool LoadMinVersion(int nVersion) {
         AssertLockHeld(cs_wallet);
         nWalletVersion = nVersion;
         nWalletMaxVersion = std::max(nWalletMaxVersion, nVersion);
         return true;
     }
     void UpdateTimeFirstKey(int64_t nCreateTime);
 
     //! Adds an encrypted key to the store, and saves it to disk.
     bool AddCryptedKey(const CPubKey &vchPubKey,
                        const std::vector<uint8_t> &vchCryptedSecret) override;
     //! Adds an encrypted key to the store, without saving it to disk (used by
     //! LoadWallet)
     bool LoadCryptedKey(const CPubKey &vchPubKey,
                         const std::vector<uint8_t> &vchCryptedSecret);
     bool AddCScript(const CScript &redeemScript) override;
     bool LoadCScript(const CScript &redeemScript);
 
     //! Adds a destination data tuple to the store, and saves it to disk
     bool AddDestData(const CTxDestination &dest, const std::string &key,
                      const std::string &value);
     //! Erases a destination data tuple in the store and on disk
     bool EraseDestData(const CTxDestination &dest, const std::string &key);
     //! Adds a destination data tuple to the store, without saving it to disk
     bool LoadDestData(const CTxDestination &dest, const std::string &key,
                       const std::string &value);
     //! Look up a destination data tuple in the store, return true if found
     //! false otherwise
     bool GetDestData(const CTxDestination &dest, const std::string &key,
                      std::string *value) const;
     //! Get all destination values matching a prefix.
     std::vector<std::string> GetDestValues(const std::string &prefix) const;
 
     //! Adds a watch-only address to the store, and saves it to disk.
     bool AddWatchOnly(const CScript &dest, int64_t nCreateTime);
     bool RemoveWatchOnly(const CScript &dest) override;
     //! Adds a watch-only address to the store, without saving it to disk (used
     //! by LoadWallet)
     bool LoadWatchOnly(const CScript &dest);
 
     //! Holds a timestamp at which point the wallet is scheduled (externally) to
     //! be relocked. Caller must arrange for actual relocking to occur via
     //! Lock().
     int64_t nRelockTime;
 
     bool Unlock(const SecureString &strWalletPassphrase);
     bool ChangeWalletPassphrase(const SecureString &strOldWalletPassphrase,
                                 const SecureString &strNewWalletPassphrase);
     bool EncryptWallet(const SecureString &strWalletPassphrase);
 
     void GetKeyBirthTimes(std::map<CTxDestination, int64_t> &mapKeyBirth) const;
     unsigned int ComputeTimeSmart(const CWalletTx &wtx) const;
 
     /**
      * Increment the next transaction order id
      * @return next transaction order id
      */
     int64_t IncOrderPosNext(CWalletDB *pwalletdb = nullptr);
     DBErrors ReorderTransactions();
     bool AccountMove(std::string strFrom, std::string strTo,
                      const Amount nAmount, std::string strComment = "");
     bool GetLabelDestination(CTxDestination &dest, const std::string &label,
                              bool bForceNew = false);
 
     void MarkDirty();
     bool AddToWallet(const CWalletTx &wtxIn, bool fFlushOnClose = true);
     bool LoadToWallet(const CWalletTx &wtxIn);
     void TransactionAddedToMempool(const CTransactionRef &tx) override;
     void
     BlockConnected(const std::shared_ptr<const CBlock> &pblock,
                    const CBlockIndex *pindex,
                    const std::vector<CTransactionRef> &vtxConflicted) override;
     void
     BlockDisconnected(const std::shared_ptr<const CBlock> &pblock) override;
     bool AddToWalletIfInvolvingMe(const CTransactionRef &tx,
                                   const CBlockIndex *pIndex, int posInBlock,
                                   bool fUpdate);
     int64_t RescanFromTime(int64_t startTime,
                            const WalletRescanReserver &reserver, bool update);
     CBlockIndex *ScanForWalletTransactions(CBlockIndex *pindexStart,
                                            CBlockIndex *pindexStop,
                                            const WalletRescanReserver &reserver,
                                            bool fUpdate = false);
     void TransactionRemovedFromMempool(const CTransactionRef &ptx) override;
     void ReacceptWalletTransactions();
     void ResendWalletTransactions(int64_t nBestBlockTime,
                                   CConnman *connman) override;
     // ResendWalletTransactionsBefore may only be called if
     // fBroadcastTransactions!
     std::vector<uint256> ResendWalletTransactionsBefore(int64_t nTime,
                                                         CConnman *connman);
     Amount GetBalance() const;
     Amount GetUnconfirmedBalance() const;
     Amount GetImmatureBalance() const;
     Amount GetWatchOnlyBalance() const;
     Amount GetUnconfirmedWatchOnlyBalance() const;
     Amount GetImmatureWatchOnlyBalance() const;
     Amount GetLegacyBalance(const isminefilter &filter, int minDepth,
                             const std::string *account) const;
     Amount GetAvailableBalance(const CCoinControl *coinControl = nullptr) const;
 
     /**
      * Insert additional inputs into the transaction by calling
      * CreateTransaction();
      */
     bool FundTransaction(CMutableTransaction &tx, Amount &nFeeRet,
                          int &nChangePosInOut, std::string &strFailReason,
                          bool lockUnspents,
                          const std::set<int> &setSubtractFeeFromOutputs,
                          CCoinControl coinControl, bool keepReserveKey);
     bool SignTransaction(CMutableTransaction &tx);
 
     /**
      * Create a new transaction paying the recipients with a set of coins
      * selected by SelectCoins(); Also create the change output, when needed
      * @note passing nChangePosInOut as -1 will result in setting a random
      * position
      */
     bool CreateTransaction(const std::vector<CRecipient> &vecSend,
                            CTransactionRef &tx, CReserveKey &reservekey,
                            Amount &nFeeRet, int &nChangePosInOut,
                            std::string &strFailReason,
                            const CCoinControl &coinControl, bool sign = true);
     bool CommitTransaction(
         CTransactionRef tx, mapValue_t mapValue,
         std::vector<std::pair<std::string, std::string>> orderForm,
         std::string fromAccount, CReserveKey &reservekey, CConnman *connman,
         CValidationState &state);
 
     void ListAccountCreditDebit(const std::string &strAccount,
                                 std::list<CAccountingEntry> &entries);
     bool AddAccountingEntry(const CAccountingEntry &);
     bool AddAccountingEntry(const CAccountingEntry &, CWalletDB *pwalletdb);
     template <typename ContainerType>
     bool DummySignTx(CMutableTransaction &txNew,
                      const ContainerType &coins) const;
 
     static CFeeRate fallbackFee;
 
     bool NewKeyPool();
     size_t KeypoolCountExternalKeys();
     bool TopUpKeyPool(unsigned int kpSize = 0);
     void ReserveKeyFromKeyPool(int64_t &nIndex, CKeyPool &keypool,
                                bool fRequestedInternal);
     void KeepKey(int64_t nIndex);
     void ReturnKey(int64_t nIndex, bool fInternal, const CPubKey &pubkey);
     bool GetKeyFromPool(CPubKey &key, bool internal = false);
     int64_t GetOldestKeyPoolTime();
     /**
      * Marks all keys in the keypool up to and including reserve_key as used.
      */
     void MarkReserveKeysAsUsed(int64_t keypool_id);
     const std::map<CKeyID, int64_t> &GetAllReserveKeys() const {
         return m_pool_key_to_index;
     }
     /** Does the wallet have at least min_keys in the keypool? */
     bool HasUnusedKeys(size_t min_keys) const;
 
     std::set<std::set<CTxDestination>> GetAddressGroupings();
     std::map<CTxDestination, Amount> GetAddressBalances();
 
     std::set<CTxDestination> GetLabelAddresses(const std::string &label) const;
 
     isminetype IsMine(const CTxIn &txin) const;
     /**
      * Returns amount of debit if the input matches the filter, otherwise
      * returns 0
      */
     Amount GetDebit(const CTxIn &txin, const isminefilter &filter) const;
     isminetype IsMine(const CTxOut &txout) const;
     Amount GetCredit(const CTxOut &txout, const isminefilter &filter) const;
     bool IsChange(const CTxOut &txout) const;
     Amount GetChange(const CTxOut &txout) const;
     bool IsMine(const CTransaction &tx) const;
     /** should probably be renamed to IsRelevantToMe */
     bool IsFromMe(const CTransaction &tx) const;
     Amount GetDebit(const CTransaction &tx, const isminefilter &filter) const;
     /** Returns whether all of the inputs match the filter */
     bool IsAllFromMe(const CTransaction &tx, const isminefilter &filter) const;
     Amount GetCredit(const CTransaction &tx, const isminefilter &filter) const;
     Amount GetChange(const CTransaction &tx) const;
     void ChainStateFlushed(const CBlockLocator &loc) override;
 
     DBErrors LoadWallet(bool &fFirstRunRet);
     DBErrors ZapWalletTx(std::vector<CWalletTx> &vWtx);
     DBErrors ZapSelectTx(std::vector<TxId> &txIdsIn,
                          std::vector<TxId> &txIdsOut);
 
     bool SetAddressBook(const CTxDestination &address,
                         const std::string &strName, const std::string &purpose);
 
     bool DelAddressBook(const CTxDestination &address);
 
     const std::string &GetLabelName(const CScript &scriptPubKey) const;
 
     void Inventory(const uint256 &hash) override {
         LOCK(cs_wallet);
         std::map<uint256, int>::iterator mi = mapRequestCount.find(hash);
         if (mi != mapRequestCount.end()) {
             (*mi).second++;
         }
     }
 
     void GetScriptForMining(std::shared_ptr<CReserveScript> &script);
 
     unsigned int GetKeyPoolSize() {
         // set{Ex,In}ternalKeyPool
         AssertLockHeld(cs_wallet);
         return setInternalKeyPool.size() + setExternalKeyPool.size();
     }
 
     //! signify that a particular wallet feature is now used. this may change
     //! nWalletVersion and nWalletMaxVersion if those are lower
     bool SetMinVersion(enum WalletFeature, CWalletDB *pwalletdbIn = nullptr,
                        bool fExplicit = false);
 
     //! change which version we're allowed to upgrade to (note that this does
     //! not immediately imply upgrading to that format)
     bool SetMaxVersion(int nVersion);
 
     //! get the current wallet format (the oldest client version guaranteed to
     //! understand this wallet)
     int GetVersion() {
         LOCK(cs_wallet);
         return nWalletVersion;
     }
 
     //! Get wallet transactions that conflict with given transaction (spend same
     //! outputs)
     std::set<TxId> GetConflicts(const TxId &txid) const;
 
     //! Check if a given transaction has any of its outputs spent by another
     //! transaction in the wallet
     bool HasWalletSpend(const TxId &txid) const;
 
     //! Flush wallet (bitdb flush)
     void Flush(bool shutdown = false);
 
     /**
      * Address book entry changed.
      * @note called with lock cs_wallet held.
      */
     boost::signals2::signal<void(CWallet *wallet, const CTxDestination &address,
                                  const std::string &label, bool isMine,
                                  const std::string &purpose, ChangeType status)>
         NotifyAddressBookChanged;
 
     /**
      * Wallet transaction added, removed or updated.
      * @note called with lock cs_wallet held.
      */
     boost::signals2::signal<void(CWallet *wallet, const TxId &txid,
                                  ChangeType status)>
         NotifyTransactionChanged;
 
     /** Show progress e.g. for rescan */
     boost::signals2::signal<void(const std::string &title, int nProgress)>
         ShowProgress;
 
     /** Watch-only address added */
     boost::signals2::signal<void(bool fHaveWatchOnly)> NotifyWatchonlyChanged;
 
     /** Inquire whether this wallet broadcasts transactions. */
     bool GetBroadcastTransactions() const { return fBroadcastTransactions; }
     /** Set whether this wallet broadcasts transactions. */
     void SetBroadcastTransactions(bool broadcast) {
         fBroadcastTransactions = broadcast;
     }
 
     /** Return whether transaction can be abandoned */
     bool TransactionCanBeAbandoned(const TxId &txid) const;
 
     /**
      * Mark a transaction (and it in-wallet descendants) as abandoned so its
      * inputs may be respent.
      */
     bool AbandonTransaction(const TxId &txid);
 
     /**
      * Initializes the wallet, returns a new CWallet instance or a null pointer
      * in case of an error.
      */
     static CWallet *CreateWalletFromFile(const CChainParams &chainParams,
                                          const std::string &name,
                                          const fs::path &path);
 
     /**
      * Wallet post-init setup
      * Gives the wallet a chance to register repetitive tasks and complete
      * post-init tasks
      */
     void postInitProcess(CScheduler &scheduler);
 
     bool BackupWallet(const std::string &strDest);
 
     /* Set the HD chain model (chain child index counters) */
     bool SetHDChain(const CHDChain &chain, bool memonly);
     const CHDChain &GetHDChain() const { return hdChain; }
 
     /* Returns true if HD is enabled */
     bool IsHDEnabled() const;
 
     /* Generates a new HD master key (will not be activated) */
     CPubKey GenerateNewHDMasterKey();
 
     /**
      * Set the current HD master key (will reset the chain child index counters)
      * Sets the master key's version based on the current wallet version (so the
      * caller must ensure the current wallet version is correct before calling
      *  this function).
      */
     bool SetHDMasterKey(const CPubKey &key);
 
     /**
      * Blocks until the wallet state is up-to-date to /at least/ the current
      * chain at the time this function is entered.
      * Obviously holding cs_main/cs_wallet when going into this call may cause
      * deadlock
      */
     void BlockUntilSyncedToCurrentChain();
 
     /**
      * Explicitly make the wallet learn the related scripts for outputs to the
      * given key. This is purely to make the wallet file compatible with older
      * software, as CBasicKeyStore automatically does this implicitly for all
      * keys now.
      */
     void LearnRelatedScripts(const CPubKey &key, OutputType);
 
     /**
      * Same as LearnRelatedScripts, but when the OutputType is not known (and
      * could be anything).
      */
     void LearnAllRelatedScripts(const CPubKey &key);
 
     /**
      * Get a destination of the requested type (if possible) to the specified
      * script. This function will automatically add the necessary scripts to the
      * wallet.
      */
     CTxDestination AddAndGetDestinationForScript(const CScript &script,
                                                  OutputType);
 };
 
 /** A key allocated from the key pool. */
 class CReserveKey final : public CReserveScript {
 protected:
     CWallet *pwallet;
     int64_t nIndex;
     CPubKey vchPubKey;
     bool fInternal;
 
 public:
     explicit CReserveKey(CWallet *pwalletIn) {
         nIndex = -1;
         pwallet = pwalletIn;
         fInternal = false;
     }
 
     CReserveKey() = default;
     CReserveKey(const CReserveKey &) = delete;
     CReserveKey &operator=(const CReserveKey &) = delete;
 
     ~CReserveKey() { ReturnKey(); }
 
     void ReturnKey();
     bool GetReservedKey(CPubKey &pubkey, bool internal = false);
     void KeepKey();
     void KeepScript() override { KeepKey(); }
 };
 
 /**
  * Account information.
  * Stored in wallet with key "acc"+string account name.
  */
 class CAccount {
 public:
     CPubKey vchPubKey;
 
     CAccount() { SetNull(); }
 
     void SetNull() { vchPubKey = CPubKey(); }
 
     ADD_SERIALIZE_METHODS;
 
     template <typename Stream, typename Operation>
     inline void SerializationOp(Stream &s, Operation ser_action) {
         int nVersion = s.GetVersion();
         if (!(s.GetType() & SER_GETHASH)) {
             READWRITE(nVersion);
         }
 
         READWRITE(vchPubKey);
     }
 };
 
 // Helper for producing a bunch of max-sized low-S signatures (eg 72 bytes)
 // ContainerType is meant to hold pair<CWalletTx *, int>, and be iterable so
 // that each entry corresponds to each vIn, in order.
 template <typename ContainerType>
 bool CWallet::DummySignTx(CMutableTransaction &txNew,
                           const ContainerType &coins) const {
     // Fill in dummy signatures for fee calculation.
     int nIn = 0;
     for (const auto &coin : coins) {
         const CScript &scriptPubKey = coin.txout.scriptPubKey;
         SignatureData sigdata;
 
         if (!ProduceSignature(DummySignatureCreator(this), scriptPubKey,
                               sigdata)) {
             return false;
         } else {
             UpdateTransaction(txNew, nIn, sigdata);
         }
 
         nIn++;
     }
 
     return true;
 }
 
 /** RAII object to check and reserve a wallet rescan */
 class WalletRescanReserver {
 private:
     CWalletRef m_wallet;
     bool m_could_reserve;
 
 public:
     explicit WalletRescanReserver(CWalletRef w)
         : m_wallet(w), m_could_reserve(false) {}
 
     bool reserve() {
         assert(!m_could_reserve);
         std::lock_guard<std::mutex> lock(m_wallet->mutexScanning);
         if (m_wallet->fScanningWallet) {
             return false;
         }
         m_wallet->fScanningWallet = true;
         m_could_reserve = true;
         return true;
     }
 
     bool isReserved() const {
         return (m_could_reserve && m_wallet->fScanningWallet);
     }
 
     ~WalletRescanReserver() {
         std::lock_guard<std::mutex> lock(m_wallet->mutexScanning);
         if (m_could_reserve) {
             m_wallet->fScanningWallet = false;
         }
     }
 };
 
 OutputType ParseOutputType(const std::string &str,
                            OutputType default_type = OutputType::DEFAULT);
 const std::string &FormatOutputType(OutputType type);
 
 /**
  * Get a destination of the requested type (if possible) to the specified key.
  * The caller must make sure LearnRelatedScripts has been called beforehand.
  */
 CTxDestination GetDestinationForKey(const CPubKey &key, OutputType);
 
 /**
  * Get all destinations (potentially) supported by the wallet for the given key.
  */
 std::vector<CTxDestination> GetAllDestinationsForKey(const CPubKey &key);
 
 #endif // BITCOIN_WALLET_WALLET_H
diff --git a/test/functional/feature_config_args.py b/test/functional/feature_config_args.py
index 666a3184f..d13494e26 100755
--- a/test/functional/feature_config_args.py
+++ b/test/functional/feature_config_args.py
@@ -1,61 +1,61 @@
 #!/usr/bin/env python3
 # Copyright (c) 2017 The Bitcoin Core developers
 # Distributed under the MIT software license, see the accompanying
 # file COPYING or http://www.opensource.org/licenses/mit-license.php.
 """Test various command line arguments and configuration file parameters."""
 import os
 
 from test_framework.test_framework import BitcoinTestFramework
 
 
 class ConfArgsTest(BitcoinTestFramework):
     def set_test_params(self):
         self.setup_clean_chain = True
         self.num_nodes = 1
 
     def run_test(self):
         self.stop_node(0)
         # Remove the -datadir argument so it doesn't override the config file
         self.nodes[0].remove_default_args(["-datadir"])
 
         default_data_dir = self.nodes[0].datadir
         new_data_dir = os.path.join(default_data_dir, 'newdatadir')
         new_data_dir_2 = os.path.join(default_data_dir, 'newdatadir2')
 
         # Check that using -datadir argument on non-existent directory fails
         self.nodes[0].datadir = new_data_dir
         self.assert_start_raises_init_error(
             0, ['-datadir='+new_data_dir],
             'Error: Specified data directory "' + new_data_dir + '" does not exist.')
 
         # Check that using non-existent datadir in conf file fails
         conf_file = os.path.join(default_data_dir, "bitcoin.conf")
 
         # datadir needs to be set before [regtest] section
         conf_file_contents = open(conf_file, encoding='utf8').read()
         with open(conf_file, 'w', encoding='utf8') as f:
             f.write("datadir=" + new_data_dir + "\n")
             f.write(conf_file_contents)
 
         self.assert_start_raises_init_error(
             0, ['-conf='+conf_file],
             'Error reading configuration file: specified data directory "' + new_data_dir + '" does not exist.')
 
         # Create the directory and ensure the config file now works
         os.mkdir(new_data_dir)
         self.start_node(0, ['-conf='+conf_file, '-wallet=w1'])
         self.stop_node(0)
-        assert os.path.isfile(os.path.join(
+        assert os.path.exists(os.path.join(
             new_data_dir, 'regtest', 'wallets', 'w1'))
 
         # Ensure command line argument overrides datadir in conf
         os.mkdir(new_data_dir_2)
         self.nodes[0].datadir = new_data_dir_2
         self.start_node(0, ['-datadir='+new_data_dir_2,
                             '-conf='+conf_file, '-wallet=w2'])
-        assert os.path.isfile(os.path.join(
+        assert os.path.exists(os.path.join(
             new_data_dir_2, 'regtest', 'wallets', 'w2'))
 
 
 if __name__ == '__main__':
     ConfArgsTest().main()
diff --git a/test/functional/wallet_multiwallet.py b/test/functional/wallet_multiwallet.py
index ed437427e..4c3a947a3 100755
--- a/test/functional/wallet_multiwallet.py
+++ b/test/functional/wallet_multiwallet.py
@@ -1,160 +1,170 @@
 #!/usr/bin/env python3
 # Copyright (c) 2017 The Bitcoin Core developers
 # Distributed under the MIT software license, see the accompanying
 # file COPYING or http://www.opensource.org/licenses/mit-license.php.
 """Test multiwallet.
 
 Verify that a bitcoind node can load multiple wallet files
 """
 import os
 import shutil
 
 from test_framework.test_framework import BitcoinTestFramework
 from test_framework.util import (
     assert_equal,
     assert_raises_rpc_error,
 )
 
 
 class MultiWalletTest(BitcoinTestFramework):
     def set_test_params(self):
         self.setup_clean_chain = True
         self.num_nodes = 2
         self.supports_cli = True
 
     def run_test(self):
         node = self.nodes[0]
 
         data_dir = lambda *p: os.path.join(node.datadir, 'regtest', *p)
         wallet_dir = lambda *p: data_dir('wallets', *p)
 
         def wallet(name): return node.get_wallet_rpc(name)
 
         # check wallet.dat is created
         self.stop_nodes()
         assert_equal(os.path.isfile(wallet_dir('wallet.dat')), True)
 
+        # create symlink to verify wallet directory path can be referenced
+        # through symlink
+        os.mkdir(wallet_dir('w7'))
+        os.symlink('w7', wallet_dir('w7_symlink'))
+
+        # rename wallet.dat to make sure plain wallet file paths (as opposed to
+        # directory paths) can be loaded
+        os.rename(wallet_dir("wallet.dat"), wallet_dir("w8"))
+
         # restart node with a mix of wallet names:
         #   w1, w2, w3 - to verify new wallets created when non-existing paths specified
         #   w          - to verify wallet name matching works when one wallet path is prefix of another
         #   sub/w5     - to verify relative wallet path is created correctly
         #   extern/w6  - to verify absolute wallet path is created correctly
-        #   wallet.dat - to verify existing wallet file is loaded correctly
+        #   w7_symlink - to verify symlinked wallet path is initialized correctly
+        #   w8         - to verify existing wallet file is loaded correctly
+        #   ''         - to verify default wallet file is created correctly
         wallet_names = ['w1', 'w2', 'w3', 'w', 'sub/w5',
-                        os.path.join(self.options.tmpdir, 'extern/w6'), 'wallet.dat']
+                        os.path.join(self.options.tmpdir, 'extern/w6'), 'w7_symlink', 'w8', '']
         extra_args = ['-wallet={}'.format(n) for n in wallet_names]
         self.start_node(0, extra_args)
         assert_equal(set(node.listwallets()), set(wallet_names))
 
         # check that all requested wallets were created
         self.stop_node(0)
         for wallet_name in wallet_names:
-            assert_equal(os.path.isfile(wallet_dir(wallet_name)), True)
+            if os.path.isdir(wallet_dir(wallet_name)):
+                assert_equal(os.path.isfile(
+                    wallet_dir(wallet_name, "wallet.dat")), True)
+            else:
+                assert_equal(os.path.isfile(wallet_dir(wallet_name)), True)
 
         # should not initialize if wallet path can't be created
         self.assert_start_raises_init_error(
-            0, ['-wallet=wallet.dat/bad'], 'File exists')
+            0, ['-wallet=wallet.dat/bad'], 'Not a directory')
 
         self.assert_start_raises_init_error(
             0, ['-walletdir=wallets'], 'Error: Specified -walletdir "wallets" does not exist')
         self.assert_start_raises_init_error(
             0, ['-walletdir=wallets'], 'Error: Specified -walletdir "wallets" is a relative path', cwd=data_dir())
         self.assert_start_raises_init_error(
             0, ['-walletdir=debug.log'], 'Error: Specified -walletdir "debug.log" is not a directory', cwd=data_dir())
 
         # should not initialize if there are duplicate wallets
         self.assert_start_raises_init_error(
             0, ['-wallet=w1', '-wallet=w1'], 'Error loading wallet w1. Duplicate -wallet filename specified.')
 
-        # should not initialize if wallet file is a directory
-        os.mkdir(wallet_dir('w11'))
-        self.assert_start_raises_init_error(
-            0, ['-wallet=w11'], 'Error loading wallet w11. -wallet filename must be a regular file.')
-
         # should not initialize if one wallet is a copy of another
-        shutil.copyfile(wallet_dir('w2'), wallet_dir('w22'))
+        shutil.copyfile(wallet_dir('w8'), wallet_dir('w8_copy'))
         self.assert_start_raises_init_error(
-            0, ['-wallet=w2', '-wallet=w22'], 'duplicates fileid')
+            0, ['-wallet=w8', '-wallet=w8_copy'], 'duplicates fileid')
 
         # should not initialize if wallet file is a symlink
-        os.symlink(wallet_dir('w1'), wallet_dir('w12'))
+        os.symlink('w8', wallet_dir('w8_symlink'))
         self.assert_start_raises_init_error(
-            0, ['-wallet=w12'], 'Error loading wallet w12. -wallet filename must be a regular file.')
+            0, ['-wallet=w8_symlink'], 'Invalid -wallet path')
 
         # should not initialize if the specified walletdir does not exist
         self.assert_start_raises_init_error(
             0, ['-walletdir=bad'], 'Error: Specified -walletdir "bad" does not exist')
         # should not initialize if the specified walletdir is not a directory
         not_a_dir = wallet_dir('notadir')
         open(not_a_dir, 'a').close()
         self.assert_start_raises_init_error(
             0, ['-walletdir='+not_a_dir], 'Error: Specified -walletdir "' + not_a_dir + '" is not a directory')
 
         # if wallets/ doesn't exist, datadir should be the default wallet dir
         wallet_dir2 = data_dir('walletdir')
         os.rename(wallet_dir(), wallet_dir2)
         self.start_node(0, ['-wallet=w4', '-wallet=w5'])
         assert_equal(set(node.listwallets()), {"w4", "w5"})
         w5 = wallet("w5")
         w5.generate(1)
 
         # now if wallets/ exists again, but the rootdir is specified as the walletdir, w4 and w5 should still be loaded
         os.rename(wallet_dir2, wallet_dir())
         self.restart_node(0, ['-wallet=w4', '-wallet=w5',
                               '-walletdir=' + data_dir()])
         assert_equal(set(node.listwallets()), {"w4", "w5"})
         w5 = wallet("w5")
         w5_info = w5.getwalletinfo()
         assert_equal(w5_info['immature_balance'], 50)
 
         competing_wallet_dir = os.path.join(
             self.options.tmpdir, 'competing_walletdir')
         os.mkdir(competing_wallet_dir)
         self.restart_node(0, ['-walletdir='+competing_wallet_dir])
         self.assert_start_raises_init_error(
             1, ['-walletdir='+competing_wallet_dir], 'Error initializing wallet database environment')
 
         self.restart_node(0, extra_args)
 
         wallets = [wallet(w) for w in wallet_names]
         wallet_bad = wallet("bad")
 
         # check wallet names and balances
         wallets[0].generate(1)
         for wallet_name, wallet in zip(wallet_names, wallets):
             info = wallet.getwalletinfo()
             assert_equal(info['immature_balance'],
                          50 if wallet is wallets[0] else 0)
             assert_equal(info['walletname'], wallet_name)
 
         # accessing invalid wallet fails
         assert_raises_rpc_error(-18, "Requested wallet does not exist or is not loaded",
                                 wallet_bad.getwalletinfo)
 
         # accessing wallet RPC without using wallet endpoint fails
         assert_raises_rpc_error(-19, "Wallet file not specified (must request wallet RPC through /wallet/<filename> uri-path).",
                                 node.getwalletinfo)
 
         w1, w2, w3, w4, *_ = wallets
         w1.generate(101)
         assert_equal(w1.getbalance(), 100)
         assert_equal(w2.getbalance(), 0)
         assert_equal(w3.getbalance(), 0)
         assert_equal(w4.getbalance(), 0)
 
         w1.sendtoaddress(w2.getnewaddress(), 1)
         w1.sendtoaddress(w3.getnewaddress(), 2)
         w1.sendtoaddress(w4.getnewaddress(), 3)
         w1.generate(1)
         assert_equal(w2.getbalance(), 1)
         assert_equal(w3.getbalance(), 2)
         assert_equal(w4.getbalance(), 3)
 
         batch = w1.batch([w1.getblockchaininfo.get_request(),
                           w1.getwalletinfo.get_request()])
         assert_equal(batch[0]["result"]["chain"], "regtest")
         assert_equal(batch[1]["result"]["walletname"], "w1")
 
 
 if __name__ == '__main__':
     MultiWalletTest().main()