Differential D4834 Diff 15923 src/script/scriptcache.h

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src/script/scriptcache.h

	// Copyright (c) 2017 - The Bitcoin Developers			// Copyright (c) 2017 - The Bitcoin Developers
	// Distributed under the MIT software license, see the accompanying			// Distributed under the MIT software license, see the accompanying
	// file COPYING or http://www.opensource.org/licenses/mit-license.php.			// file COPYING or http://www.opensource.org/licenses/mit-license.php.

	#ifndef BITCOIN_SCRIPT_SCRIPTCACHE_H			#ifndef BITCOIN_SCRIPT_SCRIPTCACHE_H
	#define BITCOIN_SCRIPT_SCRIPTCACHE_H			#define BITCOIN_SCRIPT_SCRIPTCACHE_H

	#include <uint256.h>			#include <array>

	#include <cstdint>			#include <cstdint>

	class CTransaction;			class CTransaction;

				/**
				* The script cache is a map using a key/value element, that caches the
				* success of executing a specific transaction's input scripts under a
				* specific set of flags, along with any associated information learned
				* during execution.
				*
				* The key is slightly shorter than a power-of-two size to make room for
				* the value.
				*/
				class ScriptCacheKey {
				std::array<uint8_t, 28> data;

				public:
				ScriptCacheKey() = default;
				ScriptCacheKey(const ScriptCacheKey &rhs) = default;
				ScriptCacheKey(const CTransaction &tx, uint32_t flags);

				bool operator==(const ScriptCacheKey &rhs) const {
				return rhs.data == data;
				}

				friend class ScriptCacheHasher;
				};

	// DoS prevention: limit cache size to 32MB (over 1000000 entries on 64-bit			// DoS prevention: limit cache size to 32MB (over 1000000 entries on 64-bit
	// systems). Due to how we count cache size, actual memory usage is slightly			// systems). Due to how we count cache size, actual memory usage is slightly
	// more (~32.25 MB)			// more (~32.25 MB)
	static const unsigned int DEFAULT_MAX_SCRIPT_CACHE_SIZE = 32;			static const unsigned int DEFAULT_MAX_SCRIPT_CACHE_SIZE = 32;
	// Maximum sig cache size allowed			// Maximum sig cache size allowed
	static const int64_t MAX_MAX_SCRIPT_CACHE_SIZE = 16384;			static const int64_t MAX_MAX_SCRIPT_CACHE_SIZE = 16384;

	/** Initializes the script-execution cache */			/** Initializes the script-execution cache */
	void InitScriptExecutionCache();			void InitScriptExecutionCache();

	/** Compute the cache key for a given transaction and flags. */			/**
	uint256 GetScriptCacheKey(const CTransaction &tx, uint32_t flags);			* Check if a given key is in the cache, and if so, return its values.
				* (if not found, nSigChecks may or may not be set to an arbitrary value)
	/** Check if a given key is in the cache. */			*/
	bool IsKeyInScriptCache(uint256 key, bool erase);			bool IsKeyInScriptCache(ScriptCacheKey key, bool erase, int &nSigChecksOut);

	/** Add an entry in the cache. */			/**
	void AddKeyInScriptCache(uint256 key);			* Add an entry in the cache.
				*/
				void AddKeyInScriptCache(ScriptCacheKey key, int nSigChecks);

	#endif // BITCOIN_SCRIPT_SCRIPTCACHE_H			#endif // BITCOIN_SCRIPT_SCRIPTCACHE_H