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Diffstat (limited to 'src/coins.h')
| -rw-r--r-- | src/coins.h | 356 |
1 files changed, 356 insertions, 0 deletions
diff --git a/src/coins.h b/src/coins.h new file mode 100644 index 0000000000..2c72ee88e1 --- /dev/null +++ b/src/coins.h @@ -0,0 +1,356 @@ +// Copyright (c) 2009-2010 Satoshi Nakamoto +// Copyright (c) 2009-2013 The Bitcoin developers +// Distributed under the MIT/X11 software license, see the accompanying +// file COPYING or http://www.opensource.org/licenses/mit-license.php. +#ifndef BITCOIN_COINS_H +#define BITCOIN_COINS_H + +#include "core.h" +#include "serialize.h" +#include "uint256.h" + +#include <assert.h> +#include <stdint.h> + +#include <boost/foreach.hpp> + +/** pruned version of CTransaction: only retains metadata and unspent transaction outputs + * + * Serialized format: + * - VARINT(nVersion) + * - VARINT(nCode) + * - unspentness bitvector, for vout[2] and further; least significant byte first + * - the non-spent CTxOuts (via CTxOutCompressor) + * - VARINT(nHeight) + * + * The nCode value consists of: + * - bit 1: IsCoinBase() + * - bit 2: vout[0] is not spent + * - bit 4: vout[1] is not spent + * - The higher bits encode N, the number of non-zero bytes in the following bitvector. + * - In case both bit 2 and bit 4 are unset, they encode N-1, as there must be at + * least one non-spent output). + * + * Example: 0104835800816115944e077fe7c803cfa57f29b36bf87c1d358bb85e + * <><><--------------------------------------------><----> + * | \ | / + * version code vout[1] height + * + * - version = 1 + * - code = 4 (vout[1] is not spent, and 0 non-zero bytes of bitvector follow) + * - unspentness bitvector: as 0 non-zero bytes follow, it has length 0 + * - vout[1]: 835800816115944e077fe7c803cfa57f29b36bf87c1d35 + * * 8358: compact amount representation for 60000000000 (600 BTC) + * * 00: special txout type pay-to-pubkey-hash + * * 816115944e077fe7c803cfa57f29b36bf87c1d35: address uint160 + * - height = 203998 + * + * + * Example: 0109044086ef97d5790061b01caab50f1b8e9c50a5057eb43c2d9563a4eebbd123008c988f1a4a4de2161e0f50aac7f17e7f9555caa486af3b + * <><><--><--------------------------------------------------><----------------------------------------------><----> + * / \ \ | | / + * version code unspentness vout[4] vout[16] height + * + * - version = 1 + * - code = 9 (coinbase, neither vout[0] or vout[1] are unspent, + * 2 (1, +1 because both bit 2 and bit 4 are unset) non-zero bitvector bytes follow) + * - unspentness bitvector: bits 2 (0x04) and 14 (0x4000) are set, so vout[2+2] and vout[14+2] are unspent + * - vout[4]: 86ef97d5790061b01caab50f1b8e9c50a5057eb43c2d9563a4ee + * * 86ef97d579: compact amount representation for 234925952 (2.35 BTC) + * * 00: special txout type pay-to-pubkey-hash + * * 61b01caab50f1b8e9c50a5057eb43c2d9563a4ee: address uint160 + * - vout[16]: bbd123008c988f1a4a4de2161e0f50aac7f17e7f9555caa4 + * * bbd123: compact amount representation for 110397 (0.001 BTC) + * * 00: special txout type pay-to-pubkey-hash + * * 8c988f1a4a4de2161e0f50aac7f17e7f9555caa4: address uint160 + * - height = 120891 + */ +class CCoins +{ +public: + // whether transaction is a coinbase + bool fCoinBase; + + // unspent transaction outputs; spent outputs are .IsNull(); spent outputs at the end of the array are dropped + std::vector<CTxOut> vout; + + // at which height this transaction was included in the active block chain + int nHeight; + + // version of the CTransaction; accesses to this value should probably check for nHeight as well, + // as new tx version will probably only be introduced at certain heights + int nVersion; + + // construct a CCoins from a CTransaction, at a given height + CCoins(const CTransaction &tx, int nHeightIn) : fCoinBase(tx.IsCoinBase()), vout(tx.vout), nHeight(nHeightIn), nVersion(tx.nVersion) { + ClearUnspendable(); + } + + // empty constructor + CCoins() : fCoinBase(false), vout(0), nHeight(0), nVersion(0) { } + + // remove spent outputs at the end of vout + void Cleanup() { + while (vout.size() > 0 && vout.back().IsNull()) + vout.pop_back(); + if (vout.empty()) + std::vector<CTxOut>().swap(vout); + } + + void ClearUnspendable() { + BOOST_FOREACH(CTxOut &txout, vout) { + if (txout.scriptPubKey.IsUnspendable()) + txout.SetNull(); + } + Cleanup(); + } + + void swap(CCoins &to) { + std::swap(to.fCoinBase, fCoinBase); + to.vout.swap(vout); + std::swap(to.nHeight, nHeight); + std::swap(to.nVersion, nVersion); + } + + // equality test + friend bool operator==(const CCoins &a, const CCoins &b) { + // Empty CCoins objects are always equal. + if (a.IsPruned() && b.IsPruned()) + return true; + return a.fCoinBase == b.fCoinBase && + a.nHeight == b.nHeight && + a.nVersion == b.nVersion && + a.vout == b.vout; + } + friend bool operator!=(const CCoins &a, const CCoins &b) { + return !(a == b); + } + + void CalcMaskSize(unsigned int &nBytes, unsigned int &nNonzeroBytes) const; + + bool IsCoinBase() const { + return fCoinBase; + } + + unsigned int GetSerializeSize(int nType, int nVersion) const { + unsigned int nSize = 0; + unsigned int nMaskSize = 0, nMaskCode = 0; + CalcMaskSize(nMaskSize, nMaskCode); + bool fFirst = vout.size() > 0 && !vout[0].IsNull(); + bool fSecond = vout.size() > 1 && !vout[1].IsNull(); + assert(fFirst || fSecond || nMaskCode); + unsigned int nCode = 8*(nMaskCode - (fFirst || fSecond ? 0 : 1)) + (fCoinBase ? 1 : 0) + (fFirst ? 2 : 0) + (fSecond ? 4 : 0); + // version + nSize += ::GetSerializeSize(VARINT(this->nVersion), nType, nVersion); + // size of header code + nSize += ::GetSerializeSize(VARINT(nCode), nType, nVersion); + // spentness bitmask + nSize += nMaskSize; + // txouts themself + for (unsigned int i = 0; i < vout.size(); i++) + if (!vout[i].IsNull()) + nSize += ::GetSerializeSize(CTxOutCompressor(REF(vout[i])), nType, nVersion); + // height + nSize += ::GetSerializeSize(VARINT(nHeight), nType, nVersion); + return nSize; + } + + template<typename Stream> + void Serialize(Stream &s, int nType, int nVersion) const { + unsigned int nMaskSize = 0, nMaskCode = 0; + CalcMaskSize(nMaskSize, nMaskCode); + bool fFirst = vout.size() > 0 && !vout[0].IsNull(); + bool fSecond = vout.size() > 1 && !vout[1].IsNull(); + assert(fFirst || fSecond || nMaskCode); + unsigned int nCode = 8*(nMaskCode - (fFirst || fSecond ? 0 : 1)) + (fCoinBase ? 1 : 0) + (fFirst ? 2 : 0) + (fSecond ? 4 : 0); + // version + ::Serialize(s, VARINT(this->nVersion), nType, nVersion); + // header code + ::Serialize(s, VARINT(nCode), nType, nVersion); + // spentness bitmask + for (unsigned int b = 0; b<nMaskSize; b++) { + unsigned char chAvail = 0; + for (unsigned int i = 0; i < 8 && 2+b*8+i < vout.size(); i++) + if (!vout[2+b*8+i].IsNull()) + chAvail |= (1 << i); + ::Serialize(s, chAvail, nType, nVersion); + } + // txouts themself + for (unsigned int i = 0; i < vout.size(); i++) { + if (!vout[i].IsNull()) + ::Serialize(s, CTxOutCompressor(REF(vout[i])), nType, nVersion); + } + // coinbase height + ::Serialize(s, VARINT(nHeight), nType, nVersion); + } + + template<typename Stream> + void Unserialize(Stream &s, int nType, int nVersion) { + unsigned int nCode = 0; + // version + ::Unserialize(s, VARINT(this->nVersion), nType, nVersion); + // header code + ::Unserialize(s, VARINT(nCode), nType, nVersion); + fCoinBase = nCode & 1; + std::vector<bool> vAvail(2, false); + vAvail[0] = nCode & 2; + vAvail[1] = nCode & 4; + unsigned int nMaskCode = (nCode / 8) + ((nCode & 6) != 0 ? 0 : 1); + // spentness bitmask + while (nMaskCode > 0) { + unsigned char chAvail = 0; + ::Unserialize(s, chAvail, nType, nVersion); + for (unsigned int p = 0; p < 8; p++) { + bool f = (chAvail & (1 << p)) != 0; + vAvail.push_back(f); + } + if (chAvail != 0) + nMaskCode--; + } + // txouts themself + vout.assign(vAvail.size(), CTxOut()); + for (unsigned int i = 0; i < vAvail.size(); i++) { + if (vAvail[i]) + ::Unserialize(s, REF(CTxOutCompressor(vout[i])), nType, nVersion); + } + // coinbase height + ::Unserialize(s, VARINT(nHeight), nType, nVersion); + Cleanup(); + } + + // mark an outpoint spent, and construct undo information + bool Spend(const COutPoint &out, CTxInUndo &undo); + + // mark a vout spent + bool Spend(int nPos); + + // check whether a particular output is still available + bool IsAvailable(unsigned int nPos) const { + return (nPos < vout.size() && !vout[nPos].IsNull()); + } + + // check whether the entire CCoins is spent + // note that only !IsPruned() CCoins can be serialized + bool IsPruned() const { + BOOST_FOREACH(const CTxOut &out, vout) + if (!out.IsNull()) + return false; + return true; + } +}; + + +struct CCoinsStats +{ + int nHeight; + uint256 hashBlock; + uint64_t nTransactions; + uint64_t nTransactionOutputs; + uint64_t nSerializedSize; + uint256 hashSerialized; + int64_t nTotalAmount; + + CCoinsStats() : nHeight(0), hashBlock(0), nTransactions(0), nTransactionOutputs(0), nSerializedSize(0), hashSerialized(0), nTotalAmount(0) {} +}; + + +/** Abstract view on the open txout dataset. */ +class CCoinsView +{ +public: + // Retrieve the CCoins (unspent transaction outputs) for a given txid + virtual bool GetCoins(const uint256 &txid, CCoins &coins); + + // Modify the CCoins for a given txid + virtual bool SetCoins(const uint256 &txid, const CCoins &coins); + + // Just check whether we have data for a given txid. + // This may (but cannot always) return true for fully spent transactions + virtual bool HaveCoins(const uint256 &txid); + + // Retrieve the block hash whose state this CCoinsView currently represents + virtual uint256 GetBestBlock(); + + // Modify the currently active block hash + virtual bool SetBestBlock(const uint256 &hashBlock); + + // Do a bulk modification (multiple SetCoins + one SetBestBlock) + virtual bool BatchWrite(const std::map<uint256, CCoins> &mapCoins, const uint256 &hashBlock); + + // Calculate statistics about the unspent transaction output set + virtual bool GetStats(CCoinsStats &stats); + + // As we use CCoinsViews polymorphically, have a virtual destructor + virtual ~CCoinsView() {} +}; + + +/** CCoinsView backed by another CCoinsView */ +class CCoinsViewBacked : public CCoinsView +{ +protected: + CCoinsView *base; + +public: + CCoinsViewBacked(CCoinsView &viewIn); + bool GetCoins(const uint256 &txid, CCoins &coins); + bool SetCoins(const uint256 &txid, const CCoins &coins); + bool HaveCoins(const uint256 &txid); + uint256 GetBestBlock(); + bool SetBestBlock(const uint256 &hashBlock); + void SetBackend(CCoinsView &viewIn); + bool BatchWrite(const std::map<uint256, CCoins> &mapCoins, const uint256 &hashBlock); + bool GetStats(CCoinsStats &stats); +}; + + +/** CCoinsView that adds a memory cache for transactions to another CCoinsView */ +class CCoinsViewCache : public CCoinsViewBacked +{ +protected: + uint256 hashBlock; + std::map<uint256,CCoins> cacheCoins; + +public: + CCoinsViewCache(CCoinsView &baseIn, bool fDummy = false); + + // Standard CCoinsView methods + bool GetCoins(const uint256 &txid, CCoins &coins); + bool SetCoins(const uint256 &txid, const CCoins &coins); + bool HaveCoins(const uint256 &txid); + uint256 GetBestBlock(); + bool SetBestBlock(const uint256 &hashBlock); + bool BatchWrite(const std::map<uint256, CCoins> &mapCoins, const uint256 &hashBlock); + + // Return a modifiable reference to a CCoins. Check HaveCoins first. + // Many methods explicitly require a CCoinsViewCache because of this method, to reduce + // copying. + CCoins &GetCoins(const uint256 &txid); + + // Push the modifications applied to this cache to its base. + // Failure to call this method before destruction will cause the changes to be forgotten. + bool Flush(); + + // Calculate the size of the cache (in number of transactions) + unsigned int GetCacheSize(); + + /** Amount of bitcoins coming in to a transaction + Note that lightweight clients may not know anything besides the hash of previous transactions, + so may not be able to calculate this. + + @param[in] tx transaction for which we are checking input total + @return Sum of value of all inputs (scriptSigs) + @see CTransaction::FetchInputs + */ + int64_t GetValueIn(const CTransaction& tx); + + // Check whether all prevouts of the transaction are present in the UTXO set represented by this view + bool HaveInputs(const CTransaction& tx); + + const CTxOut &GetOutputFor(const CTxIn& input); + +private: + std::map<uint256,CCoins>::iterator FetchCoins(const uint256 &txid); +}; + +#endif |