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+// 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