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// Copyright (c) 2012-2013 The Bitcoin developers
// Distributed under the MIT/X11 software license, see the accompanying
// file COPYING or http://www.opensource.org/licenses/mit-license.php.
#include "coins.h"
#include "random.h"
#include <assert.h>
// calculate number of bytes for the bitmask, and its number of non-zero bytes
// each bit in the bitmask represents the availability of one output, but the
// availabilities of the first two outputs are encoded separately
void CCoins::CalcMaskSize(unsigned int &nBytes, unsigned int &nNonzeroBytes) const {
unsigned int nLastUsedByte = 0;
for (unsigned int b = 0; 2+b*8 < vout.size(); b++) {
bool fZero = true;
for (unsigned int i = 0; i < 8 && 2+b*8+i < vout.size(); i++) {
if (!vout[2+b*8+i].IsNull()) {
fZero = false;
continue;
}
}
if (!fZero) {
nLastUsedByte = b + 1;
nNonzeroBytes++;
}
}
nBytes += nLastUsedByte;
}
bool CCoins::Spend(const COutPoint &out, CTxInUndo &undo) {
if (out.n >= vout.size())
return false;
if (vout[out.n].IsNull())
return false;
undo = CTxInUndo(vout[out.n]);
vout[out.n].SetNull();
Cleanup();
if (vout.size() == 0) {
undo.nHeight = nHeight;
undo.fCoinBase = fCoinBase;
undo.nVersion = this->nVersion;
}
return true;
}
bool CCoins::Spend(int nPos) {
CTxInUndo undo;
COutPoint out(0, nPos);
return Spend(out, undo);
}
bool CCoinsView::GetCoins(const uint256 &txid, CCoins &coins) const { return false; }
bool CCoinsView::HaveCoins(const uint256 &txid) const { return false; }
uint256 CCoinsView::GetBestBlock() const { return uint256(0); }
bool CCoinsView::BatchWrite(CCoinsMap &mapCoins, const uint256 &hashBlock) { return false; }
bool CCoinsView::GetStats(CCoinsStats &stats) const { return false; }
CCoinsViewBacked::CCoinsViewBacked(CCoinsView &viewIn) : base(&viewIn) { }
bool CCoinsViewBacked::GetCoins(const uint256 &txid, CCoins &coins) const { return base->GetCoins(txid, coins); }
bool CCoinsViewBacked::HaveCoins(const uint256 &txid) const { return base->HaveCoins(txid); }
uint256 CCoinsViewBacked::GetBestBlock() const { return base->GetBestBlock(); }
void CCoinsViewBacked::SetBackend(CCoinsView &viewIn) { base = &viewIn; }
bool CCoinsViewBacked::BatchWrite(CCoinsMap &mapCoins, const uint256 &hashBlock) { return base->BatchWrite(mapCoins, hashBlock); }
bool CCoinsViewBacked::GetStats(CCoinsStats &stats) const { return base->GetStats(stats); }
CCoinsKeyHasher::CCoinsKeyHasher() : salt(GetRandHash()) {}
CCoinsViewCache::CCoinsViewCache(CCoinsView &baseIn, bool fDummy) : CCoinsViewBacked(baseIn), hasModifier(false), hashBlock(0) { }
bool CCoinsViewCache::GetCoins(const uint256 &txid, CCoins &coins) const {
if (cacheCoins.count(txid)) {
coins = cacheCoins[txid];
return true;
}
if (base->GetCoins(txid, coins)) {
cacheCoins[txid] = coins;
return true;
}
return false;
}
CCoinsViewCache::~CCoinsViewCache()
{
assert(!hasModifier);
}
CCoinsMap::const_iterator CCoinsViewCache::FetchCoins(const uint256 &txid) const {
CCoinsMap::iterator it = cacheCoins.find(txid);
if (it != cacheCoins.end())
return it;
CCoins tmp;
if (!base->GetCoins(txid,tmp))
return cacheCoins.end();
CCoinsMap::iterator ret = cacheCoins.insert(it, std::make_pair(txid, CCoins()));
tmp.swap(ret->second);
return ret;
}
CCoinsModifier CCoinsViewCache::ModifyCoins(const uint256 &txid) {
assert(!hasModifier);
hasModifier = true;
std::pair<CCoinsMap::iterator, bool> ret = cacheCoins.insert(std::make_pair(txid, CCoins()));
if (ret.second) {
if (!base->GetCoins(txid, ret.first->second))
ret.first->second.Clear();
}
return CCoinsModifier(*this, ret.first);
}
const CCoins* CCoinsViewCache::AccessCoins(const uint256 &txid) const {
CCoinsMap::const_iterator it = FetchCoins(txid);
if (it == cacheCoins.end()) {
return NULL;
} else {
return &it->second;
}
}
bool CCoinsViewCache::HaveCoins(const uint256 &txid) const {
CCoinsMap::const_iterator it = FetchCoins(txid);
// We're using vtx.empty() instead of IsPruned here for performance reasons,
// as we only care about the case where an transaction was replaced entirely
// in a reorganization (which wipes vout entirely, as opposed to spending
// which just cleans individual outputs).
return (it != cacheCoins.end() && !it->second.vout.empty());
}
uint256 CCoinsViewCache::GetBestBlock() const {
if (hashBlock == uint256(0))
hashBlock = base->GetBestBlock();
return hashBlock;
}
void CCoinsViewCache::SetBestBlock(const uint256 &hashBlockIn) {
hashBlock = hashBlockIn;
}
bool CCoinsViewCache::BatchWrite(CCoinsMap &mapCoins, const uint256 &hashBlockIn) {
assert(!hasModifier);
for (CCoinsMap::iterator it = mapCoins.begin(); it != mapCoins.end();) {
cacheCoins[it->first].swap(it->second);
CCoinsMap::iterator itOld = it++;
mapCoins.erase(itOld);
}
hashBlock = hashBlockIn;
return true;
}
bool CCoinsViewCache::Flush() {
bool fOk = base->BatchWrite(cacheCoins, hashBlock);
cacheCoins.clear();
return fOk;
}
unsigned int CCoinsViewCache::GetCacheSize() const {
return cacheCoins.size();
}
const CTxOut &CCoinsViewCache::GetOutputFor(const CTxIn& input) const
{
const CCoins* coins = AccessCoins(input.prevout.hash);
assert(coins && coins->IsAvailable(input.prevout.n));
return coins->vout[input.prevout.n];
}
int64_t CCoinsViewCache::GetValueIn(const CTransaction& tx) const
{
if (tx.IsCoinBase())
return 0;
int64_t nResult = 0;
for (unsigned int i = 0; i < tx.vin.size(); i++)
nResult += GetOutputFor(tx.vin[i]).nValue;
return nResult;
}
bool CCoinsViewCache::HaveInputs(const CTransaction& tx) const
{
if (!tx.IsCoinBase()) {
for (unsigned int i = 0; i < tx.vin.size(); i++) {
const COutPoint &prevout = tx.vin[i].prevout;
const CCoins* coins = AccessCoins(prevout.hash);
if (!coins || !coins->IsAvailable(prevout.n)) {
return false;
}
}
}
return true;
}
double CCoinsViewCache::GetPriority(const CTransaction &tx, int nHeight) const
{
if (tx.IsCoinBase())
return 0.0;
double dResult = 0.0;
BOOST_FOREACH(const CTxIn& txin, tx.vin)
{
const CCoins* coins = AccessCoins(txin.prevout.hash);
assert(coins);
if (!coins->IsAvailable(txin.prevout.n)) continue;
if (coins->nHeight < nHeight) {
dResult += coins->vout[txin.prevout.n].nValue * (nHeight-coins->nHeight);
}
}
return tx.ComputePriority(dResult);
}
CCoinsModifier::CCoinsModifier(CCoinsViewCache& cache_, CCoinsMap::iterator it_) : cache(cache_), it(it_) {}
CCoinsModifier::~CCoinsModifier() {
assert(cache.hasModifier);
cache.hasModifier = false;
it->second.Cleanup();
}