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506 lines
17 KiB
C++
506 lines
17 KiB
C++
// Copyright (c) 2009-2010 Satoshi Nakamoto
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// Copyright (c) 2009-2022 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_CHAIN_H
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#define BITCOIN_CHAIN_H
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#include <arith_uint256.h>
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#include <consensus/params.h>
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#include <flatfile.h>
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#include <kernel/cs_main.h>
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#include <primitives/block.h>
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#include <sync.h>
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#include <uint256.h>
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#include <util/time.h>
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#include <vector>
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/**
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* Maximum amount of time that a block timestamp is allowed to exceed the
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* current network-adjusted time before the block will be accepted.
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*/
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static constexpr int64_t MAX_FUTURE_BLOCK_TIME = 2 * 60 * 60;
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/**
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* Timestamp window used as a grace period by code that compares external
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* timestamps (such as timestamps passed to RPCs, or wallet key creation times)
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* to block timestamps. This should be set at least as high as
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* MAX_FUTURE_BLOCK_TIME.
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*/
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static constexpr int64_t TIMESTAMP_WINDOW = MAX_FUTURE_BLOCK_TIME;
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/**
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* Maximum gap between node time and block time used
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* for the "Catching up..." mode in GUI.
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*
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* Ref: https://github.com/bitcoin/bitcoin/pull/1026
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*/
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static constexpr int64_t MAX_BLOCK_TIME_GAP = 90 * 60;
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class CBlockFileInfo
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{
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public:
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unsigned int nBlocks; //!< number of blocks stored in file
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unsigned int nSize; //!< number of used bytes of block file
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unsigned int nUndoSize; //!< number of used bytes in the undo file
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unsigned int nHeightFirst; //!< lowest height of block in file
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unsigned int nHeightLast; //!< highest height of block in file
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uint64_t nTimeFirst; //!< earliest time of block in file
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uint64_t nTimeLast; //!< latest time of block in file
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SERIALIZE_METHODS(CBlockFileInfo, obj)
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{
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READWRITE(VARINT(obj.nBlocks));
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READWRITE(VARINT(obj.nSize));
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READWRITE(VARINT(obj.nUndoSize));
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READWRITE(VARINT(obj.nHeightFirst));
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READWRITE(VARINT(obj.nHeightLast));
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READWRITE(VARINT(obj.nTimeFirst));
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READWRITE(VARINT(obj.nTimeLast));
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}
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void SetNull()
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{
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nBlocks = 0;
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nSize = 0;
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nUndoSize = 0;
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nHeightFirst = 0;
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nHeightLast = 0;
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nTimeFirst = 0;
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nTimeLast = 0;
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}
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CBlockFileInfo()
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{
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SetNull();
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}
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std::string ToString() const;
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/** update statistics (does not update nSize) */
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void AddBlock(unsigned int nHeightIn, uint64_t nTimeIn)
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{
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if (nBlocks == 0 || nHeightFirst > nHeightIn)
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nHeightFirst = nHeightIn;
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if (nBlocks == 0 || nTimeFirst > nTimeIn)
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nTimeFirst = nTimeIn;
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nBlocks++;
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if (nHeightIn > nHeightLast)
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nHeightLast = nHeightIn;
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if (nTimeIn > nTimeLast)
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nTimeLast = nTimeIn;
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}
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};
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enum BlockStatus : uint32_t {
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//! Unused.
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BLOCK_VALID_UNKNOWN = 0,
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//! Reserved (was BLOCK_VALID_HEADER).
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BLOCK_VALID_RESERVED = 1,
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//! All parent headers found, difficulty matches, timestamp >= median previous, checkpoint. Implies all parents
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//! are also at least TREE.
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BLOCK_VALID_TREE = 2,
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/**
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* Only first tx is coinbase, 2 <= coinbase input script length <= 100, transactions valid, no duplicate txids,
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* sigops, size, merkle root. Implies all parents are at least TREE but not necessarily TRANSACTIONS. When all
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* parent blocks also have TRANSACTIONS, CBlockIndex::nChainTx will be set.
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*/
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BLOCK_VALID_TRANSACTIONS = 3,
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//! Outputs do not overspend inputs, no double spends, coinbase output ok, no immature coinbase spends, BIP30.
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//! Implies all parents are also at least CHAIN.
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BLOCK_VALID_CHAIN = 4,
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//! Scripts & signatures ok. Implies all parents are also at least SCRIPTS.
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BLOCK_VALID_SCRIPTS = 5,
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//! All validity bits.
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BLOCK_VALID_MASK = BLOCK_VALID_RESERVED | BLOCK_VALID_TREE | BLOCK_VALID_TRANSACTIONS |
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BLOCK_VALID_CHAIN | BLOCK_VALID_SCRIPTS,
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BLOCK_HAVE_DATA = 8, //!< full block available in blk*.dat
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BLOCK_HAVE_UNDO = 16, //!< undo data available in rev*.dat
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BLOCK_HAVE_MASK = BLOCK_HAVE_DATA | BLOCK_HAVE_UNDO,
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BLOCK_FAILED_VALID = 32, //!< stage after last reached validness failed
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BLOCK_FAILED_CHILD = 64, //!< descends from failed block
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BLOCK_FAILED_MASK = BLOCK_FAILED_VALID | BLOCK_FAILED_CHILD,
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BLOCK_OPT_WITNESS = 128, //!< block data in blk*.dat was received with a witness-enforcing client
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/**
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* If set, this indicates that the block index entry is assumed-valid.
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* Certain diagnostics will be skipped in e.g. CheckBlockIndex().
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* It almost certainly means that the block's full validation is pending
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* on a background chainstate. See `doc/design/assumeutxo.md`.
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*/
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BLOCK_ASSUMED_VALID = 256,
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};
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/** The block chain is a tree shaped structure starting with the
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* genesis block at the root, with each block potentially having multiple
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* candidates to be the next block. A blockindex may have multiple pprev pointing
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* to it, but at most one of them can be part of the currently active branch.
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*/
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class CBlockIndex
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{
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public:
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//! pointer to the hash of the block, if any. Memory is owned by this CBlockIndex
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const uint256* phashBlock{nullptr};
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//! pointer to the index of the predecessor of this block
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CBlockIndex* pprev{nullptr};
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//! pointer to the index of some further predecessor of this block
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CBlockIndex* pskip{nullptr};
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//! height of the entry in the chain. The genesis block has height 0
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int nHeight{0};
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//! Which # file this block is stored in (blk?????.dat)
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int nFile GUARDED_BY(::cs_main){0};
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//! Byte offset within blk?????.dat where this block's data is stored
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unsigned int nDataPos GUARDED_BY(::cs_main){0};
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//! Byte offset within rev?????.dat where this block's undo data is stored
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unsigned int nUndoPos GUARDED_BY(::cs_main){0};
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//! (memory only) Total amount of work (expected number of hashes) in the chain up to and including this block
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arith_uint256 nChainWork{};
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//! Number of transactions in this block.
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//! Note: in a potential headers-first mode, this number cannot be relied upon
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//! Note: this value is faked during UTXO snapshot load to ensure that
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//! LoadBlockIndex() will load index entries for blocks that we lack data for.
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//! @sa ActivateSnapshot
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unsigned int nTx{0};
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//! (memory only) Number of transactions in the chain up to and including this block.
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//! This value will be non-zero only if and only if transactions for this block and all its parents are available.
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//! Change to 64-bit type before 2024 (assuming worst case of 60 byte transactions).
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//!
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//! Note: this value is faked during use of a UTXO snapshot because we don't
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//! have the underlying block data available during snapshot load.
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//! @sa AssumeutxoData
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//! @sa ActivateSnapshot
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unsigned int nChainTx{0};
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//! Verification status of this block. See enum BlockStatus
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//!
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//! Note: this value is modified to show BLOCK_OPT_WITNESS during UTXO snapshot
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//! load to avoid the block index being spuriously rewound.
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//! @sa NeedsRedownload
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//! @sa ActivateSnapshot
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uint32_t nStatus GUARDED_BY(::cs_main){0};
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//! block header
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int32_t nVersion{0};
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uint256 hashMerkleRoot{};
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uint32_t nTime{0};
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uint32_t nBits{0};
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uint32_t nNonce{0};
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//! (memory only) Sequential id assigned to distinguish order in which blocks are received.
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int32_t nSequenceId{0};
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//! (memory only) Maximum nTime in the chain up to and including this block.
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unsigned int nTimeMax{0};
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explicit CBlockIndex(const CBlockHeader& block)
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: nVersion{block.nVersion},
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hashMerkleRoot{block.hashMerkleRoot},
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nTime{block.nTime},
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nBits{block.nBits},
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nNonce{block.nNonce}
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{
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}
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FlatFilePos GetBlockPos() const EXCLUSIVE_LOCKS_REQUIRED(::cs_main)
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{
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AssertLockHeld(::cs_main);
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FlatFilePos ret;
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if (nStatus & BLOCK_HAVE_DATA) {
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ret.nFile = nFile;
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ret.nPos = nDataPos;
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}
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return ret;
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}
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FlatFilePos GetUndoPos() const EXCLUSIVE_LOCKS_REQUIRED(::cs_main)
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{
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AssertLockHeld(::cs_main);
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FlatFilePos ret;
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if (nStatus & BLOCK_HAVE_UNDO) {
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ret.nFile = nFile;
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ret.nPos = nUndoPos;
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}
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return ret;
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}
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CBlockHeader GetBlockHeader() const
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{
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CBlockHeader block;
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block.nVersion = nVersion;
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if (pprev)
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block.hashPrevBlock = pprev->GetBlockHash();
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block.hashMerkleRoot = hashMerkleRoot;
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block.nTime = nTime;
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block.nBits = nBits;
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block.nNonce = nNonce;
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return block;
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}
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uint256 GetBlockHash() const
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{
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assert(phashBlock != nullptr);
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return *phashBlock;
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}
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/**
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* Check whether this block's and all previous blocks' transactions have been
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* downloaded (and stored to disk) at some point.
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*
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* Does not imply the transactions are consensus-valid (ConnectTip might fail)
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* Does not imply the transactions are still stored on disk. (IsBlockPruned might return true)
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*/
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bool HaveTxsDownloaded() const { return nChainTx != 0; }
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NodeSeconds Time() const
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{
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return NodeSeconds{std::chrono::seconds{nTime}};
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}
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int64_t GetBlockTime() const
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{
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return (int64_t)nTime;
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}
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int64_t GetBlockTimeMax() const
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{
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return (int64_t)nTimeMax;
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}
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static constexpr int nMedianTimeSpan = 11;
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int64_t GetMedianTimePast() const
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{
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int64_t pmedian[nMedianTimeSpan];
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int64_t* pbegin = &pmedian[nMedianTimeSpan];
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int64_t* pend = &pmedian[nMedianTimeSpan];
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const CBlockIndex* pindex = this;
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for (int i = 0; i < nMedianTimeSpan && pindex; i++, pindex = pindex->pprev)
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*(--pbegin) = pindex->GetBlockTime();
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std::sort(pbegin, pend);
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return pbegin[(pend - pbegin) / 2];
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}
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std::string ToString() const;
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//! Check whether this block index entry is valid up to the passed validity level.
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bool IsValid(enum BlockStatus nUpTo = BLOCK_VALID_TRANSACTIONS) const
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EXCLUSIVE_LOCKS_REQUIRED(::cs_main)
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{
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AssertLockHeld(::cs_main);
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assert(!(nUpTo & ~BLOCK_VALID_MASK)); // Only validity flags allowed.
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if (nStatus & BLOCK_FAILED_MASK)
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return false;
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return ((nStatus & BLOCK_VALID_MASK) >= nUpTo);
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}
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//! @returns true if the block is assumed-valid; this means it is queued to be
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//! validated by a background chainstate.
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bool IsAssumedValid() const EXCLUSIVE_LOCKS_REQUIRED(::cs_main)
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{
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AssertLockHeld(::cs_main);
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return nStatus & BLOCK_ASSUMED_VALID;
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}
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//! Raise the validity level of this block index entry.
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//! Returns true if the validity was changed.
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bool RaiseValidity(enum BlockStatus nUpTo) EXCLUSIVE_LOCKS_REQUIRED(::cs_main)
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{
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AssertLockHeld(::cs_main);
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assert(!(nUpTo & ~BLOCK_VALID_MASK)); // Only validity flags allowed.
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if (nStatus & BLOCK_FAILED_MASK) return false;
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if ((nStatus & BLOCK_VALID_MASK) < nUpTo) {
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// If this block had been marked assumed-valid and we're raising
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// its validity to a certain point, there is no longer an assumption.
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if (nStatus & BLOCK_ASSUMED_VALID && nUpTo >= BLOCK_VALID_SCRIPTS) {
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nStatus &= ~BLOCK_ASSUMED_VALID;
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}
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nStatus = (nStatus & ~BLOCK_VALID_MASK) | nUpTo;
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return true;
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}
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return false;
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}
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//! Build the skiplist pointer for this entry.
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void BuildSkip();
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//! Efficiently find an ancestor of this block.
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CBlockIndex* GetAncestor(int height);
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const CBlockIndex* GetAncestor(int height) const;
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CBlockIndex() = default;
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~CBlockIndex() = default;
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protected:
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//! CBlockIndex should not allow public copy construction because equality
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//! comparison via pointer is very common throughout the codebase, making
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//! use of copy a footgun. Also, use of copies do not have the benefit
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//! of simplifying lifetime considerations due to attributes like pprev and
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//! pskip, which are at risk of becoming dangling pointers in a copied
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//! instance.
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//!
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//! We declare these protected instead of simply deleting them so that
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//! CDiskBlockIndex can reuse copy construction.
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CBlockIndex(const CBlockIndex&) = default;
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CBlockIndex& operator=(const CBlockIndex&) = delete;
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CBlockIndex(CBlockIndex&&) = delete;
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CBlockIndex& operator=(CBlockIndex&&) = delete;
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};
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arith_uint256 GetBlockProof(const CBlockIndex& block);
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/** Return the time it would take to redo the work difference between from and to, assuming the current hashrate corresponds to the difficulty at tip, in seconds. */
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int64_t GetBlockProofEquivalentTime(const CBlockIndex& to, const CBlockIndex& from, const CBlockIndex& tip, const Consensus::Params&);
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/** Find the forking point between two chain tips. */
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const CBlockIndex* LastCommonAncestor(const CBlockIndex* pa, const CBlockIndex* pb);
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/** Used to marshal pointers into hashes for db storage. */
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class CDiskBlockIndex : public CBlockIndex
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{
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public:
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uint256 hashPrev;
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CDiskBlockIndex()
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{
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hashPrev = uint256();
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}
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explicit CDiskBlockIndex(const CBlockIndex* pindex) : CBlockIndex(*pindex)
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{
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hashPrev = (pprev ? pprev->GetBlockHash() : uint256());
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}
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SERIALIZE_METHODS(CDiskBlockIndex, obj)
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{
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LOCK(::cs_main);
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int _nVersion = s.GetVersion();
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if (!(s.GetType() & SER_GETHASH)) READWRITE(VARINT_MODE(_nVersion, VarIntMode::NONNEGATIVE_SIGNED));
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READWRITE(VARINT_MODE(obj.nHeight, VarIntMode::NONNEGATIVE_SIGNED));
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READWRITE(VARINT(obj.nStatus));
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READWRITE(VARINT(obj.nTx));
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if (obj.nStatus & (BLOCK_HAVE_DATA | BLOCK_HAVE_UNDO)) READWRITE(VARINT_MODE(obj.nFile, VarIntMode::NONNEGATIVE_SIGNED));
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if (obj.nStatus & BLOCK_HAVE_DATA) READWRITE(VARINT(obj.nDataPos));
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if (obj.nStatus & BLOCK_HAVE_UNDO) READWRITE(VARINT(obj.nUndoPos));
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// block header
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READWRITE(obj.nVersion);
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READWRITE(obj.hashPrev);
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READWRITE(obj.hashMerkleRoot);
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READWRITE(obj.nTime);
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READWRITE(obj.nBits);
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READWRITE(obj.nNonce);
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}
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uint256 ConstructBlockHash() const
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{
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CBlockHeader block;
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block.nVersion = nVersion;
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block.hashPrevBlock = hashPrev;
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block.hashMerkleRoot = hashMerkleRoot;
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block.nTime = nTime;
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block.nBits = nBits;
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block.nNonce = nNonce;
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return block.GetHash();
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}
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uint256 GetBlockHash() = delete;
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std::string ToString() = delete;
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};
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/** An in-memory indexed chain of blocks. */
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class CChain
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{
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private:
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std::vector<CBlockIndex*> vChain;
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public:
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CChain() = default;
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CChain(const CChain&) = delete;
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CChain& operator=(const CChain&) = delete;
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/** Returns the index entry for the genesis block of this chain, or nullptr if none. */
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CBlockIndex* Genesis() const
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{
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return vChain.size() > 0 ? vChain[0] : nullptr;
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}
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/** Returns the index entry for the tip of this chain, or nullptr if none. */
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CBlockIndex* Tip() const
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{
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return vChain.size() > 0 ? vChain[vChain.size() - 1] : nullptr;
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}
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/** Returns the index entry at a particular height in this chain, or nullptr if no such height exists. */
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CBlockIndex* operator[](int nHeight) const
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{
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if (nHeight < 0 || nHeight >= (int)vChain.size())
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return nullptr;
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return vChain[nHeight];
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}
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/** Efficiently check whether a block is present in this chain. */
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bool Contains(const CBlockIndex* pindex) const
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{
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return (*this)[pindex->nHeight] == pindex;
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}
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/** Find the successor of a block in this chain, or nullptr if the given index is not found or is the tip. */
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CBlockIndex* Next(const CBlockIndex* pindex) const
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{
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if (Contains(pindex))
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return (*this)[pindex->nHeight + 1];
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else
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return nullptr;
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}
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/** Return the maximal height in the chain. Is equal to chain.Tip() ? chain.Tip()->nHeight : -1. */
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int Height() const
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{
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return int(vChain.size()) - 1;
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}
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/** Set/initialize a chain with a given tip. */
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void SetTip(CBlockIndex& block);
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/** Return a CBlockLocator that refers to the tip in of this chain. */
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CBlockLocator GetLocator() const;
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/** Find the last common block between this chain and a block index entry. */
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const CBlockIndex* FindFork(const CBlockIndex* pindex) const;
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/** Find the earliest block with timestamp equal or greater than the given time and height equal or greater than the given height. */
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CBlockIndex* FindEarliestAtLeast(int64_t nTime, int height) const;
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};
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/** Get a locator for a block index entry. */
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CBlockLocator GetLocator(const CBlockIndex* index);
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/** Construct a list of hash entries to put in a locator. */
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std::vector<uint256> LocatorEntries(const CBlockIndex* index);
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#endif // BITCOIN_CHAIN_H
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