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Diffstat (limited to 'src/chain.h')
| -rw-r--r-- | src/chain.h | 390 |
1 files changed, 390 insertions, 0 deletions
diff --git a/src/chain.h b/src/chain.h new file mode 100644 index 0000000000..0aafb40b98 --- /dev/null +++ b/src/chain.h @@ -0,0 +1,390 @@ +// Copyright (c) 2009-2010 Satoshi Nakamoto +// Copyright (c) 2009-2014 The Bitcoin developers +// Distributed under the MIT software license, see the accompanying +// file COPYING or http://www.opensource.org/licenses/mit-license.php. + +#ifndef H_BITCOIN_CHAIN +#define H_BITCOIN_CHAIN + +#include "core.h" +#include "pow.h" +#include "uint256.h" + +#include <vector> + +#include <boost/foreach.hpp> + +struct CDiskBlockPos +{ + int nFile; + unsigned int nPos; + + ADD_SERIALIZE_METHODS; + + template <typename Stream, typename Operation> + inline void SerializationOp(Stream& s, Operation ser_action, int nType, int nVersion) { + READWRITE(VARINT(nFile)); + READWRITE(VARINT(nPos)); + } + + CDiskBlockPos() { + SetNull(); + } + + CDiskBlockPos(int nFileIn, unsigned int nPosIn) { + nFile = nFileIn; + nPos = nPosIn; + } + + friend bool operator==(const CDiskBlockPos &a, const CDiskBlockPos &b) { + return (a.nFile == b.nFile && a.nPos == b.nPos); + } + + friend bool operator!=(const CDiskBlockPos &a, const CDiskBlockPos &b) { + return !(a == b); + } + + void SetNull() { nFile = -1; nPos = 0; } + bool IsNull() const { return (nFile == -1); } +}; + +enum BlockStatus { + BLOCK_VALID_UNKNOWN = 0, + BLOCK_VALID_HEADER = 1, // parsed, version ok, hash satisfies claimed PoW, 1 <= vtx count <= max, timestamp not in future + BLOCK_VALID_TREE = 2, // parent found, difficulty matches, timestamp >= median previous, checkpoint + BLOCK_VALID_TRANSACTIONS = 3, // only first tx is coinbase, 2 <= coinbase input script length <= 100, transactions valid, no duplicate txids, sigops, size, merkle root + BLOCK_VALID_CHAIN = 4, // outputs do not overspend inputs, no double spends, coinbase output ok, immature coinbase spends, BIP30 + BLOCK_VALID_SCRIPTS = 5, // scripts/signatures ok + BLOCK_VALID_MASK = BLOCK_VALID_HEADER | BLOCK_VALID_TREE | BLOCK_VALID_TRANSACTIONS | + BLOCK_VALID_CHAIN | BLOCK_VALID_SCRIPTS, + + BLOCK_HAVE_DATA = 8, // full block available in blk*.dat + BLOCK_HAVE_UNDO = 16, // undo data available in rev*.dat + BLOCK_HAVE_MASK = BLOCK_HAVE_DATA | BLOCK_HAVE_UNDO, + + BLOCK_FAILED_VALID = 32, // stage after last reached validness failed + BLOCK_FAILED_CHILD = 64, // descends from failed block + BLOCK_FAILED_MASK = BLOCK_FAILED_VALID | BLOCK_FAILED_CHILD, +}; + +/** The block chain is a tree shaped structure starting with the + * genesis block at the root, with each block potentially having multiple + * candidates to be the next block. A blockindex may have multiple pprev pointing + * to it, but at most one of them can be part of the currently active branch. + */ +class CBlockIndex +{ +public: + // pointer to the hash of the block, if any. memory is owned by this CBlockIndex + const uint256* phashBlock; + + // pointer to the index of the predecessor of this block + CBlockIndex* pprev; + + // pointer to the index of some further predecessor of this block + CBlockIndex* pskip; + + // height of the entry in the chain. The genesis block has height 0 + int nHeight; + + // Which # file this block is stored in (blk?????.dat) + int nFile; + + // Byte offset within blk?????.dat where this block's data is stored + unsigned int nDataPos; + + // Byte offset within rev?????.dat where this block's undo data is stored + unsigned int nUndoPos; + + // (memory only) Total amount of work (expected number of hashes) in the chain up to and including this block + uint256 nChainWork; + + // Number of transactions in this block. + // Note: in a potential headers-first mode, this number cannot be relied upon + unsigned int nTx; + + // (memory only) Number of transactions in the chain up to and including this block + unsigned int nChainTx; // change to 64-bit type when necessary; won't happen before 2030 + + // Verification status of this block. See enum BlockStatus + unsigned int nStatus; + + // block header + int nVersion; + uint256 hashMerkleRoot; + unsigned int nTime; + unsigned int nBits; + unsigned int nNonce; + + // (memory only) Sequencial id assigned to distinguish order in which blocks are received. + uint32_t nSequenceId; + + void SetNull() + { + phashBlock = NULL; + pprev = NULL; + pskip = NULL; + nHeight = 0; + nFile = 0; + nDataPos = 0; + nUndoPos = 0; + nChainWork = 0; + nTx = 0; + nChainTx = 0; + nStatus = 0; + nSequenceId = 0; + + nVersion = 0; + hashMerkleRoot = 0; + nTime = 0; + nBits = 0; + nNonce = 0; + } + + CBlockIndex() + { + SetNull(); + } + + CBlockIndex(CBlockHeader& block) + { + SetNull(); + + nVersion = block.nVersion; + hashMerkleRoot = block.hashMerkleRoot; + nTime = block.nTime; + nBits = block.nBits; + nNonce = block.nNonce; + } + + CDiskBlockPos GetBlockPos() const { + CDiskBlockPos ret; + if (nStatus & BLOCK_HAVE_DATA) { + ret.nFile = nFile; + ret.nPos = nDataPos; + } + return ret; + } + + CDiskBlockPos GetUndoPos() const { + CDiskBlockPos ret; + if (nStatus & BLOCK_HAVE_UNDO) { + ret.nFile = nFile; + ret.nPos = nUndoPos; + } + return ret; + } + + CBlockHeader GetBlockHeader() const + { + CBlockHeader block; + block.nVersion = nVersion; + if (pprev) + block.hashPrevBlock = pprev->GetBlockHash(); + block.hashMerkleRoot = hashMerkleRoot; + block.nTime = nTime; + block.nBits = nBits; + block.nNonce = nNonce; + return block; + } + + uint256 GetBlockHash() const + { + return *phashBlock; + } + + int64_t GetBlockTime() const + { + return (int64_t)nTime; + } + + uint256 GetBlockWork() const + { + return GetProofIncrement(nBits); + } + + enum { nMedianTimeSpan=11 }; + + int64_t GetMedianTimePast() const + { + int64_t pmedian[nMedianTimeSpan]; + int64_t* pbegin = &pmedian[nMedianTimeSpan]; + int64_t* pend = &pmedian[nMedianTimeSpan]; + + const CBlockIndex* pindex = this; + for (int i = 0; i < nMedianTimeSpan && pindex; i++, pindex = pindex->pprev) + *(--pbegin) = pindex->GetBlockTime(); + + std::sort(pbegin, pend); + return pbegin[(pend - pbegin)/2]; + } + + /** + * Returns true if there are nRequired or more blocks of minVersion or above + * in the last Params().ToCheckBlockUpgradeMajority() blocks, starting at pstart + * and going backwards. + */ + static bool IsSuperMajority(int minVersion, const CBlockIndex* pstart, + unsigned int nRequired); + + std::string ToString() const + { + return strprintf("CBlockIndex(pprev=%p, nHeight=%d, merkle=%s, hashBlock=%s)", + pprev, nHeight, + hashMerkleRoot.ToString(), + GetBlockHash().ToString()); + } + + // Check whether this block index entry is valid up to the passed validity level. + bool IsValid(enum BlockStatus nUpTo = BLOCK_VALID_TRANSACTIONS) const + { + assert(!(nUpTo & ~BLOCK_VALID_MASK)); // Only validity flags allowed. + if (nStatus & BLOCK_FAILED_MASK) + return false; + return ((nStatus & BLOCK_VALID_MASK) >= nUpTo); + } + + // Raise the validity level of this block index entry. + // Returns true if the validity was changed. + bool RaiseValidity(enum BlockStatus nUpTo) + { + assert(!(nUpTo & ~BLOCK_VALID_MASK)); // Only validity flags allowed. + if (nStatus & BLOCK_FAILED_MASK) + return false; + if ((nStatus & BLOCK_VALID_MASK) < nUpTo) { + nStatus = (nStatus & ~BLOCK_VALID_MASK) | nUpTo; + return true; + } + return false; + } + + // Build the skiplist pointer for this entry. + void BuildSkip(); + + // Efficiently find an ancestor of this block. + CBlockIndex* GetAncestor(int height); + const CBlockIndex* GetAncestor(int height) const; +}; + +/** Used to marshal pointers into hashes for db storage. */ +class CDiskBlockIndex : public CBlockIndex +{ +public: + uint256 hashPrev; + + CDiskBlockIndex() { + hashPrev = 0; + } + + explicit CDiskBlockIndex(CBlockIndex* pindex) : CBlockIndex(*pindex) { + hashPrev = (pprev ? pprev->GetBlockHash() : 0); + } + + ADD_SERIALIZE_METHODS; + + template <typename Stream, typename Operation> + inline void SerializationOp(Stream& s, Operation ser_action, int nType, int nVersion) { + if (!(nType & SER_GETHASH)) + READWRITE(VARINT(nVersion)); + + READWRITE(VARINT(nHeight)); + READWRITE(VARINT(nStatus)); + READWRITE(VARINT(nTx)); + if (nStatus & (BLOCK_HAVE_DATA | BLOCK_HAVE_UNDO)) + READWRITE(VARINT(nFile)); + if (nStatus & BLOCK_HAVE_DATA) + READWRITE(VARINT(nDataPos)); + if (nStatus & BLOCK_HAVE_UNDO) + READWRITE(VARINT(nUndoPos)); + + // block header + READWRITE(this->nVersion); + READWRITE(hashPrev); + READWRITE(hashMerkleRoot); + READWRITE(nTime); + READWRITE(nBits); + READWRITE(nNonce); + } + + uint256 GetBlockHash() const + { + CBlockHeader block; + block.nVersion = nVersion; + block.hashPrevBlock = hashPrev; + block.hashMerkleRoot = hashMerkleRoot; + block.nTime = nTime; + block.nBits = nBits; + block.nNonce = nNonce; + return block.GetHash(); + } + + + std::string ToString() const + { + std::string str = "CDiskBlockIndex("; + str += CBlockIndex::ToString(); + str += strprintf("\n hashBlock=%s, hashPrev=%s)", + GetBlockHash().ToString(), + hashPrev.ToString()); + return str; + } +}; + +/** An in-memory indexed chain of blocks. */ +class CChain { +private: + std::vector<CBlockIndex*> vChain; + +public: + /** Returns the index entry for the genesis block of this chain, or NULL if none. */ + CBlockIndex *Genesis() const { + return vChain.size() > 0 ? vChain[0] : NULL; + } + + /** Returns the index entry for the tip of this chain, or NULL if none. */ + CBlockIndex *Tip() const { + return vChain.size() > 0 ? vChain[vChain.size() - 1] : NULL; + } + + /** Returns the index entry at a particular height in this chain, or NULL if no such height exists. */ + CBlockIndex *operator[](int nHeight) const { + if (nHeight < 0 || nHeight >= (int)vChain.size()) + return NULL; + return vChain[nHeight]; + } + + /** Compare two chains efficiently. */ + friend bool operator==(const CChain &a, const CChain &b) { + return a.vChain.size() == b.vChain.size() && + a.vChain[a.vChain.size() - 1] == b.vChain[b.vChain.size() - 1]; + } + + /** Efficiently check whether a block is present in this chain. */ + bool Contains(const CBlockIndex *pindex) const { + return (*this)[pindex->nHeight] == pindex; + } + + /** Find the successor of a block in this chain, or NULL if the given index is not found or is the tip. */ + CBlockIndex *Next(const CBlockIndex *pindex) const { + if (Contains(pindex)) + return (*this)[pindex->nHeight + 1]; + else + return NULL; + } + + /** Return the maximal height in the chain. Is equal to chain.Tip() ? chain.Tip()->nHeight : -1. */ + int Height() const { + return vChain.size() - 1; + } + + /** Set/initialize a chain with a given tip. Returns the forking point. */ + CBlockIndex *SetTip(CBlockIndex *pindex); + + /** Return a CBlockLocator that refers to a block in this chain (by default the tip). */ + CBlockLocator GetLocator(const CBlockIndex *pindex = NULL) const; + + /** Find the last common block between this chain and a block index entry. */ + const CBlockIndex *FindFork(const CBlockIndex *pindex) const; +}; + +#endif // H_BITCOIN_CHAIN |