Files
bitcoin/src/index/db_key.h
2025-12-04 12:57:13 -05:00

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3.5 KiB
C++

// Copyright (c) 2025-present The Bitcoin Core developers
// Distributed under the MIT software license, see the accompanying
// file COPYING or http://www.opensource.org/licenses/mit-license.php.
#ifndef BITCOIN_INDEX_DB_KEY_H
#define BITCOIN_INDEX_DB_KEY_H
#include <dbwrapper.h>
#include <interfaces/types.h>
#include <logging.h>
#include <serialize.h>
#include <uint256.h>
#include <cstdint>
#include <ios>
#include <string>
#include <utility>
namespace index_util {
/*
* This file includes the logic for the db keys used by blockfilterindex and coinstatsindex.
* Index data is usually indexed by height, but in case of a reorg, entries of blocks no
* longer in the main chain will be copied to a hash index by which they can still be queried.
* Keys for the height index have the type [DB_BLOCK_HEIGHT, uint32 (BE)]. The height is represented
* as big-endian so that sequential reads of filters by height are fast.
* Keys for the hash index have the type [DB_BLOCK_HASH, uint256].
*/
static constexpr uint8_t DB_BLOCK_HASH{'s'};
static constexpr uint8_t DB_BLOCK_HEIGHT{'t'};
struct DBHeightKey {
int height;
explicit DBHeightKey(int height_in) : height(height_in) {}
template<typename Stream>
void Serialize(Stream& s) const
{
ser_writedata8(s, DB_BLOCK_HEIGHT);
ser_writedata32be(s, height);
}
template<typename Stream>
void Unserialize(Stream& s)
{
const uint8_t prefix{ser_readdata8(s)};
if (prefix != DB_BLOCK_HEIGHT) {
throw std::ios_base::failure("Invalid format for index DB height key");
}
height = ser_readdata32be(s);
}
};
struct DBHashKey {
uint256 hash;
explicit DBHashKey(const uint256& hash_in) : hash(hash_in) {}
SERIALIZE_METHODS(DBHashKey, obj) {
uint8_t prefix{DB_BLOCK_HASH};
READWRITE(prefix);
if (prefix != DB_BLOCK_HASH) {
throw std::ios_base::failure("Invalid format for index DB hash key");
}
READWRITE(obj.hash);
}
};
template <typename DBVal>
[[nodiscard]] static bool CopyHeightIndexToHashIndex(CDBIterator& db_it, CDBBatch& batch,
const std::string& index_name, int height)
{
DBHeightKey key(height);
db_it.Seek(key);
if (!db_it.GetKey(key) || key.height != height) {
LogError("unexpected key in %s: expected (%c, %d)",
index_name, DB_BLOCK_HEIGHT, height);
return false;
}
std::pair<uint256, DBVal> value;
if (!db_it.GetValue(value)) {
LogError("unable to read value in %s at key (%c, %d)",
index_name, DB_BLOCK_HEIGHT, height);
return false;
}
batch.Write(DBHashKey(value.first), value.second);
return true;
}
template <typename DBVal>
static bool LookUpOne(const CDBWrapper& db, const interfaces::BlockRef& block, DBVal& result)
{
// First check if the result is stored under the height index and the value
// there matches the block hash. This should be the case if the block is on
// the active chain.
std::pair<uint256, DBVal> read_out;
if (!db.Read(DBHeightKey(block.height), read_out)) {
return false;
}
if (read_out.first == block.hash) {
result = std::move(read_out.second);
return true;
}
// If value at the height index corresponds to an different block, the
// result will be stored in the hash index.
return db.Read(DBHashKey(block.hash), result);
}
} // namespace index_util
#endif // BITCOIN_INDEX_DB_KEY_H