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713 lines
21 KiB
C++
713 lines
21 KiB
C++
// Copyright (c) 2012-2020 The Bitcoin Core developers
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// Distributed under the MIT software license, see the accompanying
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// file COPYING or http://www.opensource.org/licenses/mit-license.php.
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#ifndef BITCOIN_DBWRAPPER_H
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#define BITCOIN_DBWRAPPER_H
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#include <clientversion.h>
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#include <fs.h>
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#include <serialize.h>
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#include <span.h>
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#include <streams.h>
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#include <util/strencodings.h>
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#include <util/system.h>
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#include <typeindex>
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#include <leveldb/db.h>
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#include <leveldb/write_batch.h>
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static const size_t DBWRAPPER_PREALLOC_KEY_SIZE = 64;
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static const size_t DBWRAPPER_PREALLOC_VALUE_SIZE = 1024;
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class dbwrapper_error : public std::runtime_error
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{
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public:
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explicit dbwrapper_error(const std::string& msg) : std::runtime_error(msg) {}
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};
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class CDBWrapper;
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/** These should be considered an implementation detail of the specific database.
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*/
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namespace dbwrapper_private {
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/** Handle database error by throwing dbwrapper_error exception.
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*/
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void HandleError(const leveldb::Status& status);
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/** Work around circular dependency, as well as for testing in dbwrapper_tests.
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* Database obfuscation should be considered an implementation detail of the
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* specific database.
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*/
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const std::vector<unsigned char>& GetObfuscateKey(const CDBWrapper &w);
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};
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/** Batch of changes queued to be written to a CDBWrapper */
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class CDBBatch
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{
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friend class CDBWrapper;
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private:
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const CDBWrapper &parent;
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leveldb::WriteBatch batch;
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CDataStream ssKey;
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CDataStream ssValue;
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size_t size_estimate;
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public:
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/**
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* @param[in] _parent CDBWrapper that this batch is to be submitted to
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*/
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explicit CDBBatch(const CDBWrapper &_parent) : parent(_parent), ssKey(SER_DISK, CLIENT_VERSION), ssValue(SER_DISK, CLIENT_VERSION), size_estimate(0) { };
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void Clear()
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{
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batch.Clear();
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size_estimate = 0;
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}
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template <typename K, typename V>
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void Write(const K& key, const V& value)
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{
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ssKey.reserve(DBWRAPPER_PREALLOC_KEY_SIZE);
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ssKey << key;
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Write(ssKey, value);
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ssKey.clear();
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}
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template <typename V>
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void Write(const CDataStream& _ssKey, const V& value)
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{
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leveldb::Slice slKey((const char*)_ssKey.data(), _ssKey.size());
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ssValue.reserve(DBWRAPPER_PREALLOC_VALUE_SIZE);
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ssValue << value;
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ssValue.Xor(dbwrapper_private::GetObfuscateKey(parent));
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leveldb::Slice slValue((const char*)ssValue.data(), ssValue.size());
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batch.Put(slKey, slValue);
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// - varint: key length (1 byte up to 127B, 2 bytes up to 16383B, ...)
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// - byte[]: key
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// - varint: value length
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// - byte[]: value
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// The formula below assumes the key and value are both less than 16k.
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size_estimate += 3 + (slKey.size() > 127) + slKey.size() + (slValue.size() > 127) + slValue.size();
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ssValue.clear();
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}
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template <typename K>
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void Erase(const K& key)
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{
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ssKey.reserve(DBWRAPPER_PREALLOC_KEY_SIZE);
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ssKey << key;
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Erase(ssKey);
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ssKey.clear();
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}
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void Erase(const CDataStream& _ssKey) {
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leveldb::Slice slKey((const char*)_ssKey.data(), _ssKey.size());
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batch.Delete(slKey);
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// - byte: header
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// - varint: key length
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// - byte[]: key
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// The formula below assumes the key is less than 16kB.
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size_estimate += 2 + (slKey.size() > 127) + slKey.size();
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}
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size_t SizeEstimate() const { return size_estimate; }
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};
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class CDBIterator
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{
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private:
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const CDBWrapper &parent;
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leveldb::Iterator *piter;
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public:
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/**
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* @param[in] _parent Parent CDBWrapper instance.
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* @param[in] _piter The original leveldb iterator.
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*/
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CDBIterator(const CDBWrapper &_parent, leveldb::Iterator *_piter) :
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parent(_parent), piter(_piter) { };
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~CDBIterator();
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bool Valid() const;
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void SeekToFirst();
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template<typename K> void Seek(const K& key) {
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CDataStream ssKey(SER_DISK, CLIENT_VERSION);
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ssKey.reserve(DBWRAPPER_PREALLOC_KEY_SIZE);
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ssKey << key;
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Seek(ssKey);
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}
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void Seek(const CDataStream& ssKey) {
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leveldb::Slice slKey((const char*)ssKey.data(), ssKey.size());
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piter->Seek(slKey);
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}
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void Next();
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template<typename K> bool GetKey(K& key) {
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try {
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CDataStream ssKey = GetKey();
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ssKey >> key;
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} catch (const std::exception&) {
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return false;
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}
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return true;
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}
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CDataStream GetKey() {
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leveldb::Slice slKey = piter->key();
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return CDataStream{MakeByteSpan(slKey), SER_DISK, CLIENT_VERSION};
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}
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unsigned int GetKeySize() {
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return piter->key().size();
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}
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template<typename V> bool GetValue(V& value) {
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leveldb::Slice slValue = piter->value();
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try {
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CDataStream ssValue{MakeByteSpan(slValue), SER_DISK, CLIENT_VERSION};
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ssValue.Xor(dbwrapper_private::GetObfuscateKey(parent));
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ssValue >> value;
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} catch (const std::exception&) {
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return false;
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}
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return true;
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}
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unsigned int GetValueSize() {
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return piter->value().size();
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}
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};
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class CDBWrapper
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{
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friend const std::vector<unsigned char>& dbwrapper_private::GetObfuscateKey(const CDBWrapper &w);
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private:
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//! custom environment this database is using (may be nullptr in case of default environment)
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leveldb::Env* penv;
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//! database options used
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leveldb::Options options;
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//! options used when reading from the database
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leveldb::ReadOptions readoptions;
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//! options used when iterating over values of the database
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leveldb::ReadOptions iteroptions;
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//! options used when writing to the database
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leveldb::WriteOptions writeoptions;
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//! options used when sync writing to the database
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leveldb::WriteOptions syncoptions;
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//! the database itself
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leveldb::DB* pdb;
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//! the name of this database
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std::string m_name;
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//! a key used for optional XOR-obfuscation of the database
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std::vector<unsigned char> obfuscate_key;
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//! the key under which the obfuscation key is stored
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static const std::string OBFUSCATE_KEY_KEY;
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//! the length of the obfuscate key in number of bytes
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static const unsigned int OBFUSCATE_KEY_NUM_BYTES;
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std::vector<unsigned char> CreateObfuscateKey() const;
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public:
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/**
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* @param[in] path Location in the filesystem where leveldb data will be stored.
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* @param[in] nCacheSize Configures various leveldb cache settings.
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* @param[in] fMemory If true, use leveldb's memory environment.
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* @param[in] fWipe If true, remove all existing data.
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* @param[in] obfuscate If true, store data obfuscated via simple XOR. If false, XOR
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* with a zero'd byte array.
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*/
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CDBWrapper(const fs::path& path, size_t nCacheSize, bool fMemory = false, bool fWipe = false, bool obfuscate = false);
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~CDBWrapper();
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CDBWrapper(const CDBWrapper&) = delete;
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CDBWrapper& operator=(const CDBWrapper&) = delete;
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template <typename K>
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bool ReadDataStream(const K& key, CDataStream& ssValue) const
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{
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CDataStream ssKey(SER_DISK, CLIENT_VERSION);
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ssKey.reserve(DBWRAPPER_PREALLOC_KEY_SIZE);
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ssKey << key;
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return ReadDataStream(ssKey, ssValue);
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}
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bool ReadDataStream(const CDataStream& ssKey, CDataStream& ssValue) const
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{
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leveldb::Slice slKey((const char*)ssKey.data(), ssKey.size());
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std::string strValue;
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leveldb::Status status = pdb->Get(readoptions, slKey, &strValue);
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if (!status.ok()) {
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if (status.IsNotFound())
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return false;
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LogPrintf("LevelDB read failure: %s\n", status.ToString());
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dbwrapper_private::HandleError(status);
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}
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CDataStream ssValueTmp{MakeByteSpan(strValue), SER_DISK, CLIENT_VERSION};
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ssValueTmp.Xor(obfuscate_key);
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ssValue = std::move(ssValueTmp);
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return true;
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}
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template <typename K, typename V>
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bool Read(const K& key, V& value) const
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{
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CDataStream ssKey(SER_DISK, CLIENT_VERSION);
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ssKey.reserve(DBWRAPPER_PREALLOC_KEY_SIZE);
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ssKey << key;
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return Read(ssKey, value);
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}
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template <typename V>
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bool Read(const CDataStream& ssKey, V& value) const
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{
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CDataStream ssValue(SER_DISK, CLIENT_VERSION);
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if (!ReadDataStream(ssKey, ssValue)) {
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return false;
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}
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try {
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ssValue >> value;
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} catch (const std::exception&) {
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return false;
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}
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return true;
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}
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template <typename K, typename V>
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bool Write(const K& key, const V& value, bool fSync = false)
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{
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CDBBatch batch(*this);
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batch.Write(key, value);
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return WriteBatch(batch, fSync);
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}
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template <typename K>
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bool Exists(const K& key) const
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{
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CDataStream ssKey(SER_DISK, CLIENT_VERSION);
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ssKey.reserve(DBWRAPPER_PREALLOC_KEY_SIZE);
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ssKey << key;
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return Exists(ssKey);
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}
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bool Exists(const CDataStream& key) const
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{
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leveldb::Slice slKey((const char*)key.data(), key.size());
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std::string strValue;
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leveldb::Status status = pdb->Get(readoptions, slKey, &strValue);
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if (!status.ok()) {
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if (status.IsNotFound())
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return false;
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LogPrintf("LevelDB read failure: %s\n", status.ToString());
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dbwrapper_private::HandleError(status);
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}
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return true;
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}
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template <typename K>
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bool Erase(const K& key, bool fSync = false)
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{
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CDBBatch batch(*this);
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batch.Erase(key);
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return WriteBatch(batch, fSync);
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}
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bool WriteBatch(CDBBatch& batch, bool fSync = false);
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// Get an estimate of LevelDB memory usage (in bytes).
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size_t DynamicMemoryUsage() const;
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CDBIterator *NewIterator()
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{
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return new CDBIterator(*this, pdb->NewIterator(iteroptions));
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}
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/**
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* Return true if the database managed by this class contains no entries.
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*/
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bool IsEmpty();
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template<typename K>
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size_t EstimateSize(const K& key_begin, const K& key_end) const
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{
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CDataStream ssKey1(SER_DISK, CLIENT_VERSION), ssKey2(SER_DISK, CLIENT_VERSION);
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ssKey1.reserve(DBWRAPPER_PREALLOC_KEY_SIZE);
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ssKey2.reserve(DBWRAPPER_PREALLOC_KEY_SIZE);
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ssKey1 << key_begin;
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ssKey2 << key_end;
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leveldb::Slice slKey1((const char*)ssKey1.data(), ssKey1.size());
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leveldb::Slice slKey2((const char*)ssKey2.data(), ssKey2.size());
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uint64_t size = 0;
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leveldb::Range range(slKey1, slKey2);
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pdb->GetApproximateSizes(&range, 1, &size);
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return size;
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}
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/**
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* Compact a certain range of keys in the database.
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*/
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template<typename K>
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void CompactRange(const K& key_begin, const K& key_end) const
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{
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CDataStream ssKey1(SER_DISK, CLIENT_VERSION), ssKey2(SER_DISK, CLIENT_VERSION);
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ssKey1.reserve(DBWRAPPER_PREALLOC_KEY_SIZE);
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ssKey2.reserve(DBWRAPPER_PREALLOC_KEY_SIZE);
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ssKey1 << key_begin;
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ssKey2 << key_end;
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leveldb::Slice slKey1((const char*)ssKey1.data(), ssKey1.size());
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leveldb::Slice slKey2((const char*)ssKey2.data(), ssKey2.size());
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pdb->CompactRange(&slKey1, &slKey2);
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}
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void CompactFull() const
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{
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pdb->CompactRange(nullptr, nullptr);
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}
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};
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template<typename CDBTransaction>
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class CDBTransactionIterator
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{
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private:
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CDBTransaction& transaction;
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typedef typename std::remove_pointer<decltype(transaction.parent.NewIterator())>::type ParentIterator;
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// We maintain 2 iterators, one for the transaction and one for the parent
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// At all times, only one of both provides the current value. The decision is made by comparing the current keys
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// of both iterators, so that always the smaller key is the current one. On Next(), the previously chosen iterator
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// is advanced.
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typename CDBTransaction::WritesMap::iterator transactionIt;
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std::unique_ptr<ParentIterator> parentIt;
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CDataStream parentKey;
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bool curIsParent{false};
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public:
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explicit CDBTransactionIterator(CDBTransaction& _transaction) :
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transaction(_transaction),
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parentKey(SER_DISK, CLIENT_VERSION)
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{
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transactionIt = transaction.writes.end();
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parentIt = std::unique_ptr<ParentIterator>(transaction.parent.NewIterator());
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}
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void SeekToFirst() {
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transactionIt = transaction.writes.begin();
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parentIt->SeekToFirst();
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SkipDeletedAndOverwritten();
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DecideCur();
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}
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template<typename K>
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void Seek(const K& key) {
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Seek(CDBTransaction::KeyToDataStream(key));
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}
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void Seek(const CDataStream& ssKey) {
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transactionIt = transaction.writes.lower_bound(ssKey);
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parentIt->Seek(ssKey);
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SkipDeletedAndOverwritten();
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DecideCur();
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}
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bool Valid() {
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return transactionIt != transaction.writes.end() || parentIt->Valid();
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}
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void Next() {
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if (transactionIt == transaction.writes.end() && !parentIt->Valid()) {
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return;
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}
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if (curIsParent) {
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assert(parentIt->Valid());
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parentIt->Next();
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SkipDeletedAndOverwritten();
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} else {
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assert(transactionIt != transaction.writes.end());
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++transactionIt;
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}
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DecideCur();
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}
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template<typename K>
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bool GetKey(K& key) {
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if (!Valid()) {
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return false;
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}
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try {
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// TODO try to avoid copy transactionIt->first (we need a stream that allows reading from external buffers)
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(curIsParent ? parentKey : CDataStream{transactionIt->first}) >> key;
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} catch (const std::exception&) {
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return false;
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}
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return true;
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}
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CDataStream GetKey() {
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if (!Valid()) {
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return CDataStream(SER_DISK, CLIENT_VERSION);
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}
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if (curIsParent) {
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return parentKey;
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} else {
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return transactionIt->first;
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}
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}
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unsigned int GetKeySize() {
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if (!Valid()) {
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return 0;
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}
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if (curIsParent) {
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return parentIt->GetKeySize();
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} else {
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return transactionIt->first.vKey.size();
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}
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}
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template<typename V>
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bool GetValue(V& value) {
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if (!Valid()) {
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return false;
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}
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if (curIsParent) {
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return transaction.Read(parentKey, value);
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} else {
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return transaction.Read(transactionIt->first, value);
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}
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};
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private:
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void SkipDeletedAndOverwritten() {
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while (parentIt->Valid()) {
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parentKey = parentIt->GetKey();
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if (!transaction.deletes.count(parentKey) && !transaction.writes.count(parentKey)) {
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break;
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}
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parentIt->Next();
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}
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}
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void DecideCur() {
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if (transactionIt != transaction.writes.end() && !parentIt->Valid()) {
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curIsParent = false;
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} else if (transactionIt == transaction.writes.end() && parentIt->Valid()) {
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curIsParent = true;
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} else if (transactionIt != transaction.writes.end() && parentIt->Valid()) {
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if (CDBTransaction::DataStreamCmp::less(transactionIt->first, parentKey)) {
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curIsParent = false;
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} else {
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curIsParent = true;
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}
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}
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}
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};
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template<typename Parent, typename CommitTarget>
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class CDBTransaction {
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friend class CDBTransactionIterator<CDBTransaction>;
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protected:
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Parent &parent;
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CommitTarget &commitTarget;
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ssize_t memoryUsage{0}; // signed, just in case we made an error in the calculations so that we don't get an overflow
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struct DataStreamCmp {
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static bool less(const CDataStream& a, const CDataStream& b) {
|
|
return std::lexicographical_compare(
|
|
(const uint8_t*)a.data(), (const uint8_t*)a.data() + a.size(),
|
|
(const uint8_t*)b.data(), (const uint8_t*)b.data() + b.size());
|
|
}
|
|
bool operator()(const CDataStream& a, const CDataStream& b) const {
|
|
return less(a, b);
|
|
}
|
|
};
|
|
|
|
struct ValueHolder {
|
|
size_t memoryUsage;
|
|
explicit ValueHolder(size_t _memoryUsage) : memoryUsage(_memoryUsage) {}
|
|
virtual ~ValueHolder() = default;
|
|
virtual void Write(const CDataStream& ssKey, CommitTarget &parent) = 0;
|
|
};
|
|
typedef std::unique_ptr<ValueHolder> ValueHolderPtr;
|
|
|
|
template <typename V>
|
|
struct ValueHolderImpl : ValueHolder {
|
|
ValueHolderImpl(const V &_value, size_t _memoryUsage) : ValueHolder(_memoryUsage), value(_value) {}
|
|
|
|
virtual void Write(const CDataStream& ssKey, CommitTarget &commitTarget) override {
|
|
// we're moving the value instead of copying it. This means that Write() can only be called once per
|
|
// ValueHolderImpl instance. Commit() clears the write maps, so this ok.
|
|
commitTarget.Write(ssKey, std::move(value));
|
|
}
|
|
V value;
|
|
};
|
|
|
|
template<typename K>
|
|
static CDataStream KeyToDataStream(const K& key) {
|
|
CDataStream ssKey(SER_DISK, CLIENT_VERSION);
|
|
ssKey.reserve(DBWRAPPER_PREALLOC_KEY_SIZE);
|
|
ssKey << key;
|
|
return ssKey;
|
|
}
|
|
|
|
typedef std::map<CDataStream, ValueHolderPtr, DataStreamCmp> WritesMap;
|
|
typedef std::set<CDataStream, DataStreamCmp> DeletesSet;
|
|
|
|
WritesMap writes;
|
|
DeletesSet deletes;
|
|
|
|
public:
|
|
CDBTransaction(Parent &_parent, CommitTarget &_commitTarget) : parent(_parent), commitTarget(_commitTarget) {}
|
|
|
|
template <typename K, typename V>
|
|
void Write(const K& key, const V& v) {
|
|
Write(KeyToDataStream(key), v);
|
|
}
|
|
|
|
template <typename V>
|
|
void Write(const CDataStream& ssKey, const V& v) {
|
|
auto valueMemoryUsage = ::GetSerializeSize(v, CLIENT_VERSION);
|
|
|
|
if (deletes.erase(ssKey)) {
|
|
memoryUsage -= ssKey.size();
|
|
}
|
|
auto it = writes.emplace(ssKey, nullptr).first;
|
|
if (it->second) {
|
|
memoryUsage -= ssKey.size() + it->second->memoryUsage;
|
|
}
|
|
it->second = std::make_unique<ValueHolderImpl<V>>(v, valueMemoryUsage);
|
|
|
|
memoryUsage += ssKey.size() + valueMemoryUsage;
|
|
}
|
|
|
|
template <typename K, typename V>
|
|
bool Read(const K& key, V& value) {
|
|
return Read(KeyToDataStream(key), value);
|
|
}
|
|
|
|
template <typename V>
|
|
bool Read(const CDataStream& ssKey, V& value) {
|
|
if (deletes.count(ssKey)) {
|
|
return false;
|
|
}
|
|
|
|
auto it = writes.find(ssKey);
|
|
if (it != writes.end()) {
|
|
auto *impl = dynamic_cast<ValueHolderImpl<V> *>(it->second.get());
|
|
if (!impl) {
|
|
throw std::runtime_error("Read called with V != previously written type");
|
|
}
|
|
value = impl->value;
|
|
return true;
|
|
}
|
|
|
|
return parent.Read(ssKey, value);
|
|
}
|
|
|
|
template <typename K>
|
|
bool Exists(const K& key) {
|
|
return Exists(KeyToDataStream(key));
|
|
}
|
|
|
|
bool Exists(const CDataStream& ssKey) {
|
|
if (deletes.count(ssKey)) {
|
|
return false;
|
|
}
|
|
|
|
if (writes.count(ssKey)) {
|
|
return true;
|
|
}
|
|
|
|
return parent.Exists(ssKey);
|
|
}
|
|
|
|
template <typename K>
|
|
void Erase(const K& key) {
|
|
return Erase(KeyToDataStream(key));
|
|
}
|
|
|
|
void Erase(const CDataStream& ssKey) {
|
|
auto it = writes.find(ssKey);
|
|
if (it != writes.end()) {
|
|
memoryUsage -= ssKey.size() + it->second->memoryUsage;
|
|
writes.erase(it);
|
|
}
|
|
if (deletes.emplace(ssKey).second) {
|
|
memoryUsage += ssKey.size();
|
|
}
|
|
}
|
|
|
|
void Clear() {
|
|
writes.clear();
|
|
deletes.clear();
|
|
memoryUsage = 0;
|
|
}
|
|
|
|
void Commit() {
|
|
for (const auto &k : deletes) {
|
|
commitTarget.Erase(k);
|
|
}
|
|
for (auto &p : writes) {
|
|
p.second->Write(p.first, commitTarget);
|
|
}
|
|
Clear();
|
|
}
|
|
|
|
bool IsClean() const {
|
|
return writes.empty() && deletes.empty();
|
|
}
|
|
|
|
size_t GetMemoryUsage() const {
|
|
if (memoryUsage < 0) {
|
|
// something went wrong when we accounted/calculated used memory...
|
|
static volatile bool didPrint = false;
|
|
if (!didPrint) {
|
|
LogPrintf("CDBTransaction::%s -- negative memoryUsage (%d)\n", __func__, memoryUsage);
|
|
didPrint = true;
|
|
}
|
|
return 0;
|
|
}
|
|
return (size_t)memoryUsage;
|
|
}
|
|
|
|
CDBTransactionIterator<CDBTransaction>* NewIterator() {
|
|
return new CDBTransactionIterator<CDBTransaction>(*this);
|
|
}
|
|
std::unique_ptr<CDBTransactionIterator<CDBTransaction>> NewIteratorUniquePtr() {
|
|
return std::make_unique<CDBTransactionIterator<CDBTransaction>>(*this);
|
|
}
|
|
};
|
|
|
|
#endif // BITCOIN_DBWRAPPER_H
|