1 files changed, 266 insertions, 0 deletions
diff --git a/src/coins.cpp b/src/coins.cpp
new file mode 100644
index 0000000000..f02949de53
--- /dev/null
+++ b/src/coins.cpp
@@ -0,0 +1,266 @@
+// Copyright (c) 2012-2014 The Bitcoin Core developers
+// Distributed under the MIT software license, see the accompanying
+// file COPYING or http://www.opensource.org/licenses/mit-license.php.
+
+#include "coins.h"
+
+#include "memusage.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(uint32_t nPos) 
+{
+    if (nPos >= vout.size() || vout[nPos].IsNull())
+        return false;
+    vout[nPos].SetNull();
+    Cleanup();
+    return true;
+}
+
+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(); }
+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) : CCoinsViewBacked(baseIn), hasModifier(false), cachedCoinsUsage(0) { }
+
+CCoinsViewCache::~CCoinsViewCache()
+{
+    assert(!hasModifier);
+}
+
+size_t CCoinsViewCache::DynamicMemoryUsage() const {
+    return memusage::DynamicUsage(cacheCoins) + cachedCoinsUsage;
+}
+
+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(std::make_pair(txid, CCoinsCacheEntry())).first;
+    tmp.swap(ret->second.coins);
+    if (ret->second.coins.IsPruned()) {
+        // The parent only has an empty entry for this txid; we can consider our
+        // version as fresh.
+        ret->second.flags = CCoinsCacheEntry::FRESH;
+    }
+    cachedCoinsUsage += ret->second.coins.DynamicMemoryUsage();
+    return ret;
+}
+
+bool CCoinsViewCache::GetCoins(const uint256 &txid, CCoins &coins) const {
+    CCoinsMap::const_iterator it = FetchCoins(txid);
+    if (it != cacheCoins.end()) {
+        coins = it->second.coins;
+        return true;
+    }
+    return false;
+}
+
+CCoinsModifier CCoinsViewCache::ModifyCoins(const uint256 &txid) {
+    assert(!hasModifier);
+    std::pair<CCoinsMap::iterator, bool> ret = cacheCoins.insert(std::make_pair(txid, CCoinsCacheEntry()));
+    size_t cachedCoinUsage = 0;
+    if (ret.second) {
+        if (!base->GetCoins(txid, ret.first->second.coins)) {
+            // The parent view does not have this entry; mark it as fresh.
+            ret.first->second.coins.Clear();
+            ret.first->second.flags = CCoinsCacheEntry::FRESH;
+        } else if (ret.first->second.coins.IsPruned()) {
+            // The parent view only has a pruned entry for this; mark it as fresh.
+            ret.first->second.flags = CCoinsCacheEntry::FRESH;
+        }
+    } else {
+        cachedCoinUsage = ret.first->second.coins.DynamicMemoryUsage();
+    }
+    // Assume that whenever ModifyCoins is called, the entry will be modified.
+    ret.first->second.flags |= CCoinsCacheEntry::DIRTY;
+    return CCoinsModifier(*this, ret.first, cachedCoinUsage);
+}
+
+const CCoins* CCoinsViewCache::AccessCoins(const uint256 &txid) const {
+    CCoinsMap::const_iterator it = FetchCoins(txid);
+    if (it == cacheCoins.end()) {
+        return NULL;
+    } else {
+        return &it->second.coins;
+    }
+}
+
+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 a 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.coins.vout.empty());
+}
+
+uint256 CCoinsViewCache::GetBestBlock() const {
+    if (hashBlock.IsNull())
+        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();) {
+        if (it->second.flags & CCoinsCacheEntry::DIRTY) { // Ignore non-dirty entries (optimization).
+            CCoinsMap::iterator itUs = cacheCoins.find(it->first);
+            if (itUs == cacheCoins.end()) {
+                if (!it->second.coins.IsPruned()) {
+                    // The parent cache does not have an entry, while the child
+                    // cache does have (a non-pruned) one. Move the data up, and
+                    // mark it as fresh (if the grandparent did have it, we
+                    // would have pulled it in at first GetCoins).
+                    assert(it->second.flags & CCoinsCacheEntry::FRESH);
+                    CCoinsCacheEntry& entry = cacheCoins[it->first];
+                    entry.coins.swap(it->second.coins);
+                    cachedCoinsUsage += entry.coins.DynamicMemoryUsage();
+                    entry.flags = CCoinsCacheEntry::DIRTY | CCoinsCacheEntry::FRESH;
+                }
+            } else {
+                if ((itUs->second.flags & CCoinsCacheEntry::FRESH) && it->second.coins.IsPruned()) {
+                    // The grandparent does not have an entry, and the child is
+                    // modified and being pruned. This means we can just delete
+                    // it from the parent.
+                    cachedCoinsUsage -= itUs->second.coins.DynamicMemoryUsage();
+                    cacheCoins.erase(itUs);
+                } else {
+                    // A normal modification.
+                    cachedCoinsUsage -= itUs->second.coins.DynamicMemoryUsage();
+                    itUs->second.coins.swap(it->second.coins);
+                    cachedCoinsUsage += itUs->second.coins.DynamicMemoryUsage();
+                    itUs->second.flags |= CCoinsCacheEntry::DIRTY;
+                }
+            }
+        }
+        CCoinsMap::iterator itOld = it++;
+        mapCoins.erase(itOld);
+    }
+    hashBlock = hashBlockIn;
+    return true;
+}
+
+bool CCoinsViewCache::Flush() {
+    bool fOk = base->BatchWrite(cacheCoins, hashBlock);
+    cacheCoins.clear();
+    cachedCoinsUsage = 0;
+    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];
+}
+
+CAmount CCoinsViewCache::GetValueIn(const CTransaction& tx) const
+{
+    if (tx.IsCoinBase())
+        return 0;
+
+    CAmount 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_, size_t usage) : cache(cache_), it(it_), cachedCoinUsage(usage) {
+    assert(!cache.hasModifier);
+    cache.hasModifier = true;
+}
+
+CCoinsModifier::~CCoinsModifier()
+{
+    assert(cache.hasModifier);
+    cache.hasModifier = false;
+    it->second.coins.Cleanup();
+    cache.cachedCoinsUsage -= cachedCoinUsage; // Subtract the old usage
+    if ((it->second.flags & CCoinsCacheEntry::FRESH) && it->second.coins.IsPruned()) {
+        cache.cacheCoins.erase(it);
+    } else {
+        // If the coin still exists after the modification, add the new usage
+        cache.cachedCoinsUsage += it->second.coins.DynamicMemoryUsage();
+    }
+}