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// Copyright (c) 2009-2010 Satoshi Nakamoto
// Copyright (c) 2009-2013 The Bitcoin developers
// Distributed under the MIT/X11 software license, see the accompanying
// file COPYING or http://www.opensource.org/licenses/mit-license.php.
#ifndef BITCOIN_DB_H
#define BITCOIN_DB_H
#include "serialize.h"
#include "sync.h"
#include "version.h"
#include <map>
#include <string>
#include <vector>
#include <boost/filesystem/path.hpp>
#include <db_cxx.h>
class CDiskBlockIndex;
class COutPoint;
struct CBlockLocator;
extern unsigned int nWalletDBUpdated;
void ThreadFlushWalletDB(const std::string& strWalletFile);
class CDBEnv
{
private:
bool fDbEnvInit;
bool fMockDb;
boost::filesystem::path path;
void EnvShutdown();
public:
mutable CCriticalSection cs_db;
DbEnv dbenv;
std::map<std::string, int> mapFileUseCount;
std::map<std::string, Db*> mapDb;
CDBEnv();
~CDBEnv();
void MakeMock();
bool IsMock() { return fMockDb; }
/*
* Verify that database file strFile is OK. If it is not,
* call the callback to try to recover.
* This must be called BEFORE strFile is opened.
* Returns true if strFile is OK.
*/
enum VerifyResult { VERIFY_OK,
RECOVER_OK,
RECOVER_FAIL };
VerifyResult Verify(std::string strFile, bool (*recoverFunc)(CDBEnv& dbenv, std::string strFile));
/*
* Salvage data from a file that Verify says is bad.
* fAggressive sets the DB_AGGRESSIVE flag (see berkeley DB->verify() method documentation).
* Appends binary key/value pairs to vResult, returns true if successful.
* NOTE: reads the entire database into memory, so cannot be used
* for huge databases.
*/
typedef std::pair<std::vector<unsigned char>, std::vector<unsigned char> > KeyValPair;
bool Salvage(std::string strFile, bool fAggressive, std::vector<KeyValPair>& vResult);
bool Open(const boost::filesystem::path& path);
void Close();
void Flush(bool fShutdown);
void CheckpointLSN(const std::string& strFile);
void CloseDb(const std::string& strFile);
bool RemoveDb(const std::string& strFile);
DbTxn* TxnBegin(int flags = DB_TXN_WRITE_NOSYNC)
{
DbTxn* ptxn = NULL;
int ret = dbenv.txn_begin(NULL, &ptxn, flags);
if (!ptxn || ret != 0)
return NULL;
return ptxn;
}
};
extern CDBEnv bitdb;
/** RAII class that provides access to a Berkeley database */
class CDB
{
protected:
Db* pdb;
std::string strFile;
DbTxn* activeTxn;
bool fReadOnly;
explicit CDB(const std::string& strFilename, const char* pszMode = "r+");
~CDB() { Close(); }
public:
void Flush();
void Close();
private:
CDB(const CDB&);
void operator=(const CDB&);
protected:
template <typename K, typename T>
bool Read(const K& key, T& value)
{
if (!pdb)
return false;
// Key
CDataStream ssKey(SER_DISK, CLIENT_VERSION);
ssKey.reserve(1000);
ssKey << key;
Dbt datKey(&ssKey[0], ssKey.size());
// Read
Dbt datValue;
datValue.set_flags(DB_DBT_MALLOC);
int ret = pdb->get(activeTxn, &datKey, &datValue, 0);
memset(datKey.get_data(), 0, datKey.get_size());
if (datValue.get_data() == NULL)
return false;
// Unserialize value
try {
CDataStream ssValue((char*)datValue.get_data(), (char*)datValue.get_data() + datValue.get_size(), SER_DISK, CLIENT_VERSION);
ssValue >> value;
} catch (const std::exception&) {
return false;
}
// Clear and free memory
memset(datValue.get_data(), 0, datValue.get_size());
free(datValue.get_data());
return (ret == 0);
}
template <typename K, typename T>
bool Write(const K& key, const T& value, bool fOverwrite = true)
{
if (!pdb)
return false;
if (fReadOnly)
assert(!"Write called on database in read-only mode");
// Key
CDataStream ssKey(SER_DISK, CLIENT_VERSION);
ssKey.reserve(1000);
ssKey << key;
Dbt datKey(&ssKey[0], ssKey.size());
// Value
CDataStream ssValue(SER_DISK, CLIENT_VERSION);
ssValue.reserve(10000);
ssValue << value;
Dbt datValue(&ssValue[0], ssValue.size());
// Write
int ret = pdb->put(activeTxn, &datKey, &datValue, (fOverwrite ? 0 : DB_NOOVERWRITE));
// Clear memory in case it was a private key
memset(datKey.get_data(), 0, datKey.get_size());
memset(datValue.get_data(), 0, datValue.get_size());
return (ret == 0);
}
template <typename K>
bool Erase(const K& key)
{
if (!pdb)
return false;
if (fReadOnly)
assert(!"Erase called on database in read-only mode");
// Key
CDataStream ssKey(SER_DISK, CLIENT_VERSION);
ssKey.reserve(1000);
ssKey << key;
Dbt datKey(&ssKey[0], ssKey.size());
// Erase
int ret = pdb->del(activeTxn, &datKey, 0);
// Clear memory
memset(datKey.get_data(), 0, datKey.get_size());
return (ret == 0 || ret == DB_NOTFOUND);
}
template <typename K>
bool Exists(const K& key)
{
if (!pdb)
return false;
// Key
CDataStream ssKey(SER_DISK, CLIENT_VERSION);
ssKey.reserve(1000);
ssKey << key;
Dbt datKey(&ssKey[0], ssKey.size());
// Exists
int ret = pdb->exists(activeTxn, &datKey, 0);
// Clear memory
memset(datKey.get_data(), 0, datKey.get_size());
return (ret == 0);
}
Dbc* GetCursor()
{
if (!pdb)
return NULL;
Dbc* pcursor = NULL;
int ret = pdb->cursor(NULL, &pcursor, 0);
if (ret != 0)
return NULL;
return pcursor;
}
int ReadAtCursor(Dbc* pcursor, CDataStream& ssKey, CDataStream& ssValue, unsigned int fFlags = DB_NEXT)
{
// Read at cursor
Dbt datKey;
if (fFlags == DB_SET || fFlags == DB_SET_RANGE || fFlags == DB_GET_BOTH || fFlags == DB_GET_BOTH_RANGE) {
datKey.set_data(&ssKey[0]);
datKey.set_size(ssKey.size());
}
Dbt datValue;
if (fFlags == DB_GET_BOTH || fFlags == DB_GET_BOTH_RANGE) {
datValue.set_data(&ssValue[0]);
datValue.set_size(ssValue.size());
}
datKey.set_flags(DB_DBT_MALLOC);
datValue.set_flags(DB_DBT_MALLOC);
int ret = pcursor->get(&datKey, &datValue, fFlags);
if (ret != 0)
return ret;
else if (datKey.get_data() == NULL || datValue.get_data() == NULL)
return 99999;
// Convert to streams
ssKey.SetType(SER_DISK);
ssKey.clear();
ssKey.write((char*)datKey.get_data(), datKey.get_size());
ssValue.SetType(SER_DISK);
ssValue.clear();
ssValue.write((char*)datValue.get_data(), datValue.get_size());
// Clear and free memory
memset(datKey.get_data(), 0, datKey.get_size());
memset(datValue.get_data(), 0, datValue.get_size());
free(datKey.get_data());
free(datValue.get_data());
return 0;
}
public:
bool TxnBegin()
{
if (!pdb || activeTxn)
return false;
DbTxn* ptxn = bitdb.TxnBegin();
if (!ptxn)
return false;
activeTxn = ptxn;
return true;
}
bool TxnCommit()
{
if (!pdb || !activeTxn)
return false;
int ret = activeTxn->commit(0);
activeTxn = NULL;
return (ret == 0);
}
bool TxnAbort()
{
if (!pdb || !activeTxn)
return false;
int ret = activeTxn->abort();
activeTxn = NULL;
return (ret == 0);
}
bool ReadVersion(int& nVersion)
{
nVersion = 0;
return Read(std::string("version"), nVersion);
}
bool WriteVersion(int nVersion)
{
return Write(std::string("version"), nVersion);
}
bool static Rewrite(const std::string& strFile, const char* pszSkip = NULL);
};
#endif // BITCOIN_DB_H

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