Merge pull request #3199 from sipa/mempoolmove

Cleanup refactoring of coins/mempool

13 files changed, 613 insertions, 605 deletions

diff --git a/src/Makefile.am b/src/Makefile.am
index 2571a6d755..d4d17b2a9b 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -14,7 +14,7 @@ DIST_SUBDIRS = . qt test
 # bitcoin core #
 BITCOIN_CORE_H = addrman.h alert.h allocators.h base58.h bignum.h \
   bitcoinrpc.h bloom.h chainparams.h checkpoints.h checkqueue.h \
-  clientversion.h compat.h core.h crypter.h db.h hash.h init.h \
+  clientversion.h compat.h core.h coins.h crypter.h db.h hash.h init.h \
   key.h keystore.h leveldbwrapper.h limitedmap.h main.h miner.h mruset.h \
   netbase.h net.h noui.h protocol.h script.h serialize.h sync.h threadsafety.h \
   txdb.h txmempool.h ui_interface.h uint256.h util.h version.h walletdb.h wallet.h
@@ -32,7 +32,7 @@ obj/build.h: FORCE
 version.o: obj/build.h
 
 libbitcoin_a_SOURCES = addrman.cpp alert.cpp allocators.cpp bitcoinrpc.cpp bloom.cpp \
-  chainparams.cpp checkpoints.cpp core.cpp crypter.cpp db.cpp hash.cpp \
+  chainparams.cpp checkpoints.cpp core.cpp coins.cpp crypter.cpp db.cpp hash.cpp \
   init.cpp key.cpp keystore.cpp leveldbwrapper.cpp main.cpp miner.cpp \
   netbase.cpp net.cpp noui.cpp protocol.cpp rpcblockchain.cpp rpcdump.cpp \
   rpcmining.cpp rpcnet.cpp rpcrawtransaction.cpp rpcwallet.cpp script.cpp \
diff --git a/src/coins.cpp b/src/coins.cpp
new file mode 100644
index 0000000000..ed82c9df8b
--- /dev/null
+++ b/src/coins.cpp
@@ -0,0 +1,180 @@
+// 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 <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) { return false; }
+bool CCoinsView::SetCoins(const uint256 &txid, const CCoins &coins) { return false; }
+bool CCoinsView::HaveCoins(const uint256 &txid) { return false; }
+uint256 CCoinsView::GetBestBlock() { return uint256(0); }
+bool CCoinsView::SetBestBlock(const uint256 &hashBlock) { return false; }
+bool CCoinsView::BatchWrite(const std::map<uint256, CCoins> &mapCoins, const uint256 &hashBlock) { return false; }
+bool CCoinsView::GetStats(CCoinsStats &stats) { return false; }
+
+
+CCoinsViewBacked::CCoinsViewBacked(CCoinsView &viewIn) : base(&viewIn) { }
+bool CCoinsViewBacked::GetCoins(const uint256 &txid, CCoins &coins) { return base->GetCoins(txid, coins); }
+bool CCoinsViewBacked::SetCoins(const uint256 &txid, const CCoins &coins) { return base->SetCoins(txid, coins); }
+bool CCoinsViewBacked::HaveCoins(const uint256 &txid) { return base->HaveCoins(txid); }
+uint256 CCoinsViewBacked::GetBestBlock() { return base->GetBestBlock(); }
+bool CCoinsViewBacked::SetBestBlock(const uint256 &hashBlock) { return base->SetBestBlock(hashBlock); }
+void CCoinsViewBacked::SetBackend(CCoinsView &viewIn) { base = &viewIn; }
+bool CCoinsViewBacked::BatchWrite(const std::map<uint256, CCoins> &mapCoins, const uint256 &hashBlock) { return base->BatchWrite(mapCoins, hashBlock); }
+bool CCoinsViewBacked::GetStats(CCoinsStats &stats) { return base->GetStats(stats); }
+
+CCoinsViewCache::CCoinsViewCache(CCoinsView &baseIn, bool fDummy) : CCoinsViewBacked(baseIn), hashBlock(0) { }
+
+bool CCoinsViewCache::GetCoins(const uint256 &txid, CCoins &coins) {
+    if (cacheCoins.count(txid)) {
+        coins = cacheCoins[txid];
+        return true;
+    }
+    if (base->GetCoins(txid, coins)) {
+        cacheCoins[txid] = coins;
+        return true;
+    }
+    return false;
+}
+
+std::map<uint256,CCoins>::iterator CCoinsViewCache::FetchCoins(const uint256 &txid) {
+    std::map<uint256,CCoins>::iterator it = cacheCoins.lower_bound(txid);
+    if (it != cacheCoins.end() && it->first == txid)
+        return it;
+    CCoins tmp;
+    if (!base->GetCoins(txid,tmp))
+        return cacheCoins.end();
+    std::map<uint256,CCoins>::iterator ret = cacheCoins.insert(it, std::make_pair(txid, CCoins()));
+    tmp.swap(ret->second);
+    return ret;
+}
+
+CCoins &CCoinsViewCache::GetCoins(const uint256 &txid) {
+    std::map<uint256,CCoins>::iterator it = FetchCoins(txid);
+    assert(it != cacheCoins.end());
+    return it->second;
+}
+
+bool CCoinsViewCache::SetCoins(const uint256 &txid, const CCoins &coins) {
+    cacheCoins[txid] = coins;
+    return true;
+}
+
+bool CCoinsViewCache::HaveCoins(const uint256 &txid) {
+    return FetchCoins(txid) != cacheCoins.end();
+}
+
+uint256 CCoinsViewCache::GetBestBlock() {
+    if (hashBlock == uint256(0))
+        hashBlock = base->GetBestBlock();
+    return hashBlock;
+}
+
+bool CCoinsViewCache::SetBestBlock(const uint256 &hashBlockIn) {
+    hashBlock = hashBlockIn;
+    return true;
+}
+
+bool CCoinsViewCache::BatchWrite(const std::map<uint256, CCoins> &mapCoins, const uint256 &hashBlockIn) {
+    for (std::map<uint256, CCoins>::const_iterator it = mapCoins.begin(); it != mapCoins.end(); it++)
+        cacheCoins[it->first] = it->second;
+    hashBlock = hashBlockIn;
+    return true;
+}
+
+bool CCoinsViewCache::Flush() {
+    bool fOk = base->BatchWrite(cacheCoins, hashBlock);
+    if (fOk)
+        cacheCoins.clear();
+    return fOk;
+}
+
+unsigned int CCoinsViewCache::GetCacheSize() {
+    return cacheCoins.size();
+}
+
+const CTxOut &CCoinsViewCache::GetOutputFor(const CTxIn& input)
+{
+    const CCoins &coins = GetCoins(input.prevout.hash);
+    assert(coins.IsAvailable(input.prevout.n));
+    return coins.vout[input.prevout.n];
+}
+
+int64_t CCoinsViewCache::GetValueIn(const CTransaction& tx)
+{
+    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)
+{
+    if (!tx.IsCoinBase()) {
+        // first check whether information about the prevout hash is available
+        for (unsigned int i = 0; i < tx.vin.size(); i++) {
+            const COutPoint &prevout = tx.vin[i].prevout;
+            if (!HaveCoins(prevout.hash))
+                return false;
+        }
+
+        // then check whether the actual outputs are available
+        for (unsigned int i = 0; i < tx.vin.size(); i++) {
+            const COutPoint &prevout = tx.vin[i].prevout;
+            const CCoins &coins = GetCoins(prevout.hash);
+            if (!coins.IsAvailable(prevout.n))
+                return false;
+        }
+    }
+    return true;
+}
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
diff --git a/src/core.cpp b/src/core.cpp
index 26c2cfc5c5..80cdcb0849 100644
--- a/src/core.cpp
+++ b/src/core.cpp
@@ -183,49 +183,6 @@ uint64_t CTxOutCompressor::DecompressAmount(uint64_t x)
     return n;
 }
 
-// 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);
-}
-
 uint256 CBlockHeader::GetHash() const
 {
     return Hash(BEGIN(nVersion), END(nNonce));
diff --git a/src/core.h b/src/core.h
index c881a78f9d..e31a7e6582 100644
--- a/src/core.h
+++ b/src/core.h
@@ -12,8 +12,6 @@
 
 #include <stdint.h>
 
-#include <boost/foreach.hpp>
-
 class CTransaction;
 
 /** An outpoint - a combination of a transaction hash and an index n into its vout */
@@ -324,232 +322,6 @@ public:
 };
 
 
-/** 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;
-    }
-};
-
-
 /** Nodes collect new transactions into a block, hash them into a hash tree,
  * and scan through nonce values to make the block's hash satisfy proof-of-work
  * requirements.  When they solve the proof-of-work, they broadcast the block
diff --git a/src/main.cpp b/src/main.cpp
index 11f262d9cb..8aef91d829 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -229,128 +229,6 @@ CBlockIndex *CChain::FindFork(const CBlockLocator &locator) const {
     return Genesis();
 }
 
-//////////////////////////////////////////////////////////////////////////////
-//
-// CCoinsView implementations
-//
-
-bool CCoinsView::GetCoins(const uint256 &txid, CCoins &coins) { return false; }
-bool CCoinsView::SetCoins(const uint256 &txid, const CCoins &coins) { return false; }
-bool CCoinsView::HaveCoins(const uint256 &txid) { return false; }
-CBlockIndex *CCoinsView::GetBestBlock() { return NULL; }
-bool CCoinsView::SetBestBlock(CBlockIndex *pindex) { return false; }
-bool CCoinsView::BatchWrite(const std::map<uint256, CCoins> &mapCoins, CBlockIndex *pindex) { return false; }
-bool CCoinsView::GetStats(CCoinsStats &stats) { return false; }
-
-
-CCoinsViewBacked::CCoinsViewBacked(CCoinsView &viewIn) : base(&viewIn) { }
-bool CCoinsViewBacked::GetCoins(const uint256 &txid, CCoins &coins) { return base->GetCoins(txid, coins); }
-bool CCoinsViewBacked::SetCoins(const uint256 &txid, const CCoins &coins) { return base->SetCoins(txid, coins); }
-bool CCoinsViewBacked::HaveCoins(const uint256 &txid) { return base->HaveCoins(txid); }
-CBlockIndex *CCoinsViewBacked::GetBestBlock() { return base->GetBestBlock(); }
-bool CCoinsViewBacked::SetBestBlock(CBlockIndex *pindex) { return base->SetBestBlock(pindex); }
-void CCoinsViewBacked::SetBackend(CCoinsView &viewIn) { base = &viewIn; }
-bool CCoinsViewBacked::BatchWrite(const std::map<uint256, CCoins> &mapCoins, CBlockIndex *pindex) { return base->BatchWrite(mapCoins, pindex); }
-bool CCoinsViewBacked::GetStats(CCoinsStats &stats) { return base->GetStats(stats); }
-
-CCoinsViewCache::CCoinsViewCache(CCoinsView &baseIn, bool fDummy) : CCoinsViewBacked(baseIn), pindexTip(NULL) { }
-
-bool CCoinsViewCache::GetCoins(const uint256 &txid, CCoins &coins) {
-    if (cacheCoins.count(txid)) {
-        coins = cacheCoins[txid];
-        return true;
-    }
-    if (base->GetCoins(txid, coins)) {
-        cacheCoins[txid] = coins;
-        return true;
-    }
-    return false;
-}
-
-std::map<uint256,CCoins>::iterator CCoinsViewCache::FetchCoins(const uint256 &txid) {
-    std::map<uint256,CCoins>::iterator it = cacheCoins.lower_bound(txid);
-    if (it != cacheCoins.end() && it->first == txid)
-        return it;
-    CCoins tmp;
-    if (!base->GetCoins(txid,tmp))
-        return cacheCoins.end();
-    std::map<uint256,CCoins>::iterator ret = cacheCoins.insert(it, std::make_pair(txid, CCoins()));
-    tmp.swap(ret->second);
-    return ret;
-}
-
-CCoins &CCoinsViewCache::GetCoins(const uint256 &txid) {
-    std::map<uint256,CCoins>::iterator it = FetchCoins(txid);
-    assert(it != cacheCoins.end());
-    return it->second;
-}
-
-bool CCoinsViewCache::SetCoins(const uint256 &txid, const CCoins &coins) {
-    cacheCoins[txid] = coins;
-    return true;
-}
-
-bool CCoinsViewCache::HaveCoins(const uint256 &txid) {
-    return FetchCoins(txid) != cacheCoins.end();
-}
-
-CBlockIndex *CCoinsViewCache::GetBestBlock() {
-    if (pindexTip == NULL)
-        pindexTip = base->GetBestBlock();
-    return pindexTip;
-}
-
-bool CCoinsViewCache::SetBestBlock(CBlockIndex *pindex) {
-    pindexTip = pindex;
-    return true;
-}
-
-bool CCoinsViewCache::BatchWrite(const std::map<uint256, CCoins> &mapCoins, CBlockIndex *pindex) {
-    for (std::map<uint256, CCoins>::const_iterator it = mapCoins.begin(); it != mapCoins.end(); it++)
-        cacheCoins[it->first] = it->second;
-    pindexTip = pindex;
-    return true;
-}
-
-bool CCoinsViewCache::Flush() {
-    bool fOk = base->BatchWrite(cacheCoins, pindexTip);
-    if (fOk)
-        cacheCoins.clear();
-    return fOk;
-}
-
-unsigned int CCoinsViewCache::GetCacheSize() {
-    return cacheCoins.size();
-}
-
-/** Helper; lookup from tip (used calling mempool.check()
-    NOTE: code calling this MUST hold the cs_main lock so
-    another thread doesn't modify pcoinsTip. When we switch
-    to C++11 this should be replaced by lambda expressions...
- **/
-static CCoins &LookupFromTip(const uint256& hash) {
-    return pcoinsTip->GetCoins(hash);
-}
-
-/** CCoinsView that brings transactions from a memorypool into view.
-    It does not check for spendings by memory pool transactions. */
-CCoinsViewMemPool::CCoinsViewMemPool(CCoinsView &baseIn, CTxMemPool &mempoolIn) : CCoinsViewBacked(baseIn), mempool(mempoolIn) { }
-
-bool CCoinsViewMemPool::GetCoins(const uint256 &txid, CCoins &coins) {
-    if (base->GetCoins(txid, coins))
-        return true;
-    CTransaction tx;
-    if (mempool.lookup(txid, tx)) {
-        coins = CCoins(tx, MEMPOOL_HEIGHT);
-        return true;
-    }
-    return false;
-}
-
-bool CCoinsViewMemPool::HaveCoins(const uint256 &txid) {
-    return mempool.exists(txid) || base->HaveCoins(txid);
-}
-
 CCoinsViewCache *pcoinsTip = NULL;
 CBlockTreeDB *pblocktree = NULL;
 
@@ -1430,25 +1308,6 @@ void UpdateTime(CBlockHeader& block, const CBlockIndex* pindexPrev)
 
 
 
-const CTxOut &CCoinsViewCache::GetOutputFor(const CTxIn& input)
-{
-    const CCoins &coins = GetCoins(input.prevout.hash);
-    assert(coins.IsAvailable(input.prevout.n));
-    return coins.vout[input.prevout.n];
-}
-
-int64_t CCoinsViewCache::GetValueIn(const CTransaction& tx)
-{
-    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;
-}
-
 void UpdateCoins(const CTransaction& tx, CValidationState &state, CCoinsViewCache &inputs, CTxUndo &txundo, int nHeight, const uint256 &txhash)
 {
     // mark inputs spent
@@ -1465,27 +1324,6 @@ void UpdateCoins(const CTransaction& tx, CValidationState &state, CCoinsViewCach
     assert(inputs.SetCoins(txhash, CCoins(tx, nHeight)));
 }
 
-bool CCoinsViewCache::HaveInputs(const CTransaction& tx)
-{
-    if (!tx.IsCoinBase()) {
-        // first check whether information about the prevout hash is available
-        for (unsigned int i = 0; i < tx.vin.size(); i++) {
-            const COutPoint &prevout = tx.vin[i].prevout;
-            if (!HaveCoins(prevout.hash))
-                return false;
-        }
-
-        // then check whether the actual outputs are available
-        for (unsigned int i = 0; i < tx.vin.size(); i++) {
-            const COutPoint &prevout = tx.vin[i].prevout;
-            const CCoins &coins = GetCoins(prevout.hash);
-            if (!coins.IsAvailable(prevout.n))
-                return false;
-        }
-    }
-    return true;
-}
-
 bool CScriptCheck::operator()() const {
     const CScript &scriptSig = ptxTo->vin[nIn].scriptSig;
     if (!VerifyScript(scriptSig, scriptPubKey, *ptxTo, nIn, nFlags, nHashType))
@@ -1512,7 +1350,8 @@ bool CheckInputs(const CTransaction& tx, CValidationState &state, CCoinsViewCach
 
         // While checking, GetBestBlock() refers to the parent block.
         // This is also true for mempool checks.
-        int nSpendHeight = inputs.GetBestBlock()->nHeight + 1;
+        CBlockIndex *pindexPrev = mapBlockIndex.find(inputs.GetBestBlock())->second;
+        int nSpendHeight = pindexPrev->nHeight + 1;
         int64_t nValueIn = 0;
         int64_t nFees = 0;
         for (unsigned int i = 0; i < tx.vin.size(); i++)
@@ -1588,7 +1427,7 @@ bool CheckInputs(const CTransaction& tx, CValidationState &state, CCoinsViewCach
 
 bool DisconnectBlock(CBlock& block, CValidationState& state, CBlockIndex* pindex, CCoinsViewCache& view, bool* pfClean)
 {
-    assert(pindex == view.GetBestBlock());
+    assert(pindex->GetBlockHash() == view.GetBestBlock());
 
     if (pfClean)
         *pfClean = false;
@@ -1664,7 +1503,7 @@ bool DisconnectBlock(CBlock& block, CValidationState& state, CBlockIndex* pindex
     }
 
     // move best block pointer to prevout block
-    view.SetBestBlock(pindex->pprev);
+    view.SetBestBlock(pindex->pprev->GetBlockHash());
 
     if (pfClean) {
         *pfClean = fClean;
@@ -1713,12 +1552,13 @@ bool ConnectBlock(CBlock& block, CValidationState& state, CBlockIndex* pindex, C
         return false;
 
     // verify that the view's current state corresponds to the previous block
-    assert(pindex->pprev == view.GetBestBlock());
+    uint256 hashPrevBlock = pindex->pprev == NULL ? uint256(0) : pindex->pprev->GetBlockHash();
+    assert(hashPrevBlock == view.GetBestBlock());
 
     // Special case for the genesis block, skipping connection of its transactions
     // (its coinbase is unspendable)
     if (block.GetHash() == Params().HashGenesisBlock()) {
-        view.SetBestBlock(pindex);
+        view.SetBestBlock(pindex->GetBlockHash());
         return true;
     }
 
@@ -1855,7 +1695,7 @@ bool ConnectBlock(CBlock& block, CValidationState& state, CBlockIndex* pindex, C
             return state.Abort(_("Failed to write transaction index"));
 
     // add this block to the view's block chain
-    assert(view.SetBestBlock(pindex));
+    assert(view.SetBestBlock(pindex->GetBlockHash()));
 
     // Watch for transactions paying to me
     for (unsigned int i = 0; i < block.vtx.size(); i++)
@@ -1866,14 +1706,16 @@ bool ConnectBlock(CBlock& block, CValidationState& state, CBlockIndex* pindex, C
 
 bool SetBestChain(CValidationState &state, CBlockIndex* pindexNew)
 {
-    mempool.check(&LookupFromTip);
+    mempool.check(pcoinsTip);
 
     // All modifications to the coin state will be done in this cache.
     // Only when all have succeeded, we push it to pcoinsTip.
     CCoinsViewCache view(*pcoinsTip, true);
 
     // Find the fork (typically, there is none)
-    CBlockIndex* pfork = view.GetBestBlock();
+    std::map<uint256, CBlockIndex*>::iterator it = mapBlockIndex.find(view.GetBestBlock());
+    CBlockIndex* ptip = (it != mapBlockIndex.end()) ? it->second : NULL;
+    CBlockIndex* pfork = ptip;
     CBlockIndex* plonger = pindexNew;
     while (pfork && pfork != plonger)
     {
@@ -1889,7 +1731,7 @@ bool SetBestChain(CValidationState &state, CBlockIndex* pindexNew)
 
     // List of what to disconnect (typically nothing)
     vector<CBlockIndex*> vDisconnect;
-    for (CBlockIndex* pindex = view.GetBestBlock(); pindex != pfork; pindex = pindex->pprev)
+    for (CBlockIndex* pindex = ptip; pindex != pfork; pindex = pindex->pprev)
         vDisconnect.push_back(pindex);
 
     // List of what to connect (typically only pindexNew)
@@ -1989,7 +1831,7 @@ bool SetBestChain(CValidationState &state, CBlockIndex* pindexNew)
         mempool.removeConflicts(tx);
     }
 
-    mempool.check(&LookupFromTip);
+    mempool.check(pcoinsTip);
 
     // Update best block in wallet (so we can detect restored wallets)
     if ((pindexNew->nHeight % 20160) == 0 || (!fIsInitialDownload && (pindexNew->nHeight % 144) == 0))
@@ -2730,9 +2572,10 @@ bool static LoadBlockIndexDB()
     LogPrintf("LoadBlockIndexDB(): transaction index %s\n", fTxIndex ? "enabled" : "disabled");
 
     // Load pointer to end of best chain
-    chainActive.SetTip(pcoinsTip->GetBestBlock());
-    if (chainActive.Tip() == NULL)
+    std::map<uint256, CBlockIndex*>::iterator it = mapBlockIndex.find(pcoinsTip->GetBestBlock());
+    if (it == mapBlockIndex.end())
         return true;
+    chainActive.SetTip(it->second);
     LogPrintf("LoadBlockIndexDB(): hashBestChain=%s  height=%d date=%s\n",
         chainActive.Tip()->GetBlockHash().ToString().c_str(), chainActive.Height(),
         DateTimeStrFormat("%Y-%m-%d %H:%M:%S", chainActive.Tip()->GetBlockTime()).c_str());
@@ -3580,7 +3423,7 @@ bool static ProcessMessage(CNode* pfrom, string strCommand, CDataStream& vRecv)
         CValidationState state;
         if (AcceptToMemoryPool(mempool, state, tx, true, &fMissingInputs))
         {
-            mempool.check(&LookupFromTip);
+            mempool.check(pcoinsTip);
             RelayTransaction(tx, inv.hash);
             mapAlreadyAskedFor.erase(inv);
             vWorkQueue.push_back(inv.hash);
@@ -3616,7 +3459,7 @@ bool static ProcessMessage(CNode* pfrom, string strCommand, CDataStream& vRecv)
                         vEraseQueue.push_back(orphanHash);
                         LogPrint("mempool", "   removed orphan tx %s\n", orphanHash.ToString().c_str());
                     }
-                    mempool.check(&LookupFromTip);
+                    mempool.check(pcoinsTip);
                 }
             }
 
diff --git a/src/main.h b/src/main.h
index 460929d624..b02aa60665 100644
--- a/src/main.h
+++ b/src/main.h
@@ -12,6 +12,7 @@
 
 #include "bignum.h"
 #include "chainparams.h"
+#include "coins.h"
 #include "core.h"
 #include "net.h"
 #include "script.h"
@@ -48,8 +49,6 @@ static const unsigned int MAX_BLOCKFILE_SIZE = 0x8000000; // 128 MiB
 static const unsigned int BLOCKFILE_CHUNK_SIZE = 0x1000000; // 16 MiB
 /** The pre-allocation chunk size for rev?????.dat files (since 0.8) */
 static const unsigned int UNDOFILE_CHUNK_SIZE = 0x100000; // 1 MiB
-/** Fake height value used in CCoins to signify they are only in the memory pool (since 0.8) */
-static const unsigned int MEMPOOL_HEIGHT = 0x7FFFFFFF;
 /** No amount larger than this (in satoshi) is valid */
 static const int64_t MAX_MONEY = 21000000 * COIN;
 inline bool MoneyRange(int64_t nValue) { return (nValue >= 0 && nValue <= MAX_MONEY); }
@@ -111,8 +110,6 @@ class CCoinsDB;
 class CBlockTreeDB;
 struct CDiskBlockPos;
 class CTxUndo;
-class CCoinsView;
-class CCoinsViewCache;
 class CScriptCheck;
 class CValidationState;
 class CWalletInterface;
@@ -1049,135 +1046,6 @@ public:
 extern CChain chainActive;
 
 
-
-
-
-
-
-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 index whose state this CCoinsView currently represents
-    virtual CBlockIndex *GetBestBlock();
-
-    // Modify the currently active block index
-    virtual bool SetBestBlock(CBlockIndex *pindex);
-
-    // Do a bulk modification (multiple SetCoins + one SetBestBlock)
-    virtual bool BatchWrite(const std::map<uint256, CCoins> &mapCoins, CBlockIndex *pindex);
-
-    // 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);
-    CBlockIndex *GetBestBlock();
-    bool SetBestBlock(CBlockIndex *pindex);
-    void SetBackend(CCoinsView &viewIn);
-    bool BatchWrite(const std::map<uint256, CCoins> &mapCoins, CBlockIndex *pindex);
-    bool GetStats(CCoinsStats &stats);
-};
-
-/** CCoinsView that adds a memory cache for transactions to another CCoinsView */
-class CCoinsViewCache : public CCoinsViewBacked
-{
-protected:
-    CBlockIndex *pindexTip;
-    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);
-    CBlockIndex *GetBestBlock();
-    bool SetBestBlock(CBlockIndex *pindex);
-    bool BatchWrite(const std::map<uint256, CCoins> &mapCoins, CBlockIndex *pindex);
-
-    // 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);
-};
-
-/** CCoinsView that brings transactions from a memorypool into view.
-    It does not check for spendings by memory pool transactions. */
-class CCoinsViewMemPool : public CCoinsViewBacked
-{
-protected:
-    CTxMemPool &mempool;
-
-public:
-    CCoinsViewMemPool(CCoinsView &baseIn, CTxMemPool &mempoolIn);
-    bool GetCoins(const uint256 &txid, CCoins &coins);
-    bool HaveCoins(const uint256 &txid);
-};
-
 /** Global variable that points to the active CCoinsView (protected by cs_main) */
 extern CCoinsViewCache *pcoinsTip;
 
diff --git a/src/net.h b/src/net.h
index b07c10610d..4f3d400058 100644
--- a/src/net.h
+++ b/src/net.h
@@ -32,7 +32,6 @@
 
 class CAddrMan;
 class CBlockIndex;
-class CNetAddr;
 class CNode;
 
 namespace boost {
diff --git a/src/rpcblockchain.cpp b/src/rpcblockchain.cpp
index 18e213257e..483d8d2e8d 100644
--- a/src/rpcblockchain.cpp
+++ b/src/rpcblockchain.cpp
@@ -245,11 +245,13 @@ Value gettxout(const Array& params, bool fHelp)
     if (n<0 || (unsigned int)n>=coins.vout.size() || coins.vout[n].IsNull())
         return Value::null;
 
-    ret.push_back(Pair("bestblock", pcoinsTip->GetBestBlock()->GetBlockHash().GetHex()));
+    std::map<uint256, CBlockIndex*>::iterator it = mapBlockIndex.find(pcoinsTip->GetBestBlock());
+    CBlockIndex *pindex = it->second;
+    ret.push_back(Pair("bestblock", pindex->GetBlockHash().GetHex()));
     if ((unsigned int)coins.nHeight == MEMPOOL_HEIGHT)
         ret.push_back(Pair("confirmations", 0));
     else
-        ret.push_back(Pair("confirmations", pcoinsTip->GetBestBlock()->nHeight - coins.nHeight + 1));
+        ret.push_back(Pair("confirmations", pindex->nHeight - coins.nHeight + 1));
     ret.push_back(Pair("value", ValueFromAmount(coins.vout[n].nValue)));
     Object o;
     ScriptPubKeyToJSON(coins.vout[n].scriptPubKey, o, true);
diff --git a/src/txdb.cpp b/src/txdb.cpp
index 3c8b0b7fe1..99deb31404 100644
--- a/src/txdb.cpp
+++ b/src/txdb.cpp
@@ -40,30 +40,27 @@ bool CCoinsViewDB::HaveCoins(const uint256 &txid) {
     return db.Exists(make_pair('c', txid)); 
 }
 
-CBlockIndex *CCoinsViewDB::GetBestBlock() {
+uint256 CCoinsViewDB::GetBestBlock() {
     uint256 hashBestChain;
     if (!db.Read('B', hashBestChain))
-        return NULL;
-    std::map<uint256, CBlockIndex*>::iterator it = mapBlockIndex.find(hashBestChain);
-    if (it == mapBlockIndex.end())
-        return NULL;
-    return it->second;
+        return uint256(0);
+    return hashBestChain;
 }
 
-bool CCoinsViewDB::SetBestBlock(CBlockIndex *pindex) {
+bool CCoinsViewDB::SetBestBlock(const uint256 &hashBlock) {
     CLevelDBBatch batch;
-    BatchWriteHashBestChain(batch, pindex->GetBlockHash()); 
+    BatchWriteHashBestChain(batch, hashBlock);
     return db.WriteBatch(batch);
 }
 
-bool CCoinsViewDB::BatchWrite(const std::map<uint256, CCoins> &mapCoins, CBlockIndex *pindex) {
+bool CCoinsViewDB::BatchWrite(const std::map<uint256, CCoins> &mapCoins, const uint256 &hashBlock) {
     LogPrint("coindb", "Committing %u changed transactions to coin database...\n", (unsigned int)mapCoins.size());
 
     CLevelDBBatch batch;
     for (std::map<uint256, CCoins>::const_iterator it = mapCoins.begin(); it != mapCoins.end(); it++)
         BatchWriteCoins(batch, it->first, it->second);
-    if (pindex)
-        BatchWriteHashBestChain(batch, pindex->GetBlockHash());
+    if (hashBlock != uint256(0))
+        BatchWriteHashBestChain(batch, hashBlock);
 
     return db.WriteBatch(batch);
 }
@@ -115,7 +112,7 @@ bool CCoinsViewDB::GetStats(CCoinsStats &stats) {
     pcursor->SeekToFirst();
 
     CHashWriter ss(SER_GETHASH, PROTOCOL_VERSION);
-    stats.hashBlock = GetBestBlock()->GetBlockHash();
+    stats.hashBlock = GetBestBlock();
     ss << stats.hashBlock;
     int64_t nTotalAmount = 0;
     while (pcursor->Valid()) {
@@ -155,7 +152,7 @@ bool CCoinsViewDB::GetStats(CCoinsStats &stats) {
         }
     }
     delete pcursor;
-    stats.nHeight = GetBestBlock()->nHeight;
+    stats.nHeight = mapBlockIndex.find(GetBestBlock())->second->nHeight;
     stats.hashSerialized = ss.GetHash();
     stats.nTotalAmount = nTotalAmount;
     return true;
diff --git a/src/txdb.h b/src/txdb.h
index 8043a595a8..7ce6585d37 100644
--- a/src/txdb.h
+++ b/src/txdb.h
@@ -29,9 +29,9 @@ public:
     bool GetCoins(const uint256 &txid, CCoins &coins);
     bool SetCoins(const uint256 &txid, const CCoins &coins);
     bool HaveCoins(const uint256 &txid);
-    CBlockIndex *GetBestBlock();
-    bool SetBestBlock(CBlockIndex *pindex);
-    bool BatchWrite(const std::map<uint256, CCoins> &mapCoins, CBlockIndex *pindex);
+    uint256 GetBestBlock();
+    bool SetBestBlock(const uint256 &hashBlock);
+    bool BatchWrite(const std::map<uint256, CCoins> &mapCoins, const uint256 &hashBlock);
     bool GetStats(CCoinsStats &stats);
 };
 
diff --git a/src/txmempool.cpp b/src/txmempool.cpp
index 975955a458..d501b89ecf 100644
--- a/src/txmempool.cpp
+++ b/src/txmempool.cpp
@@ -105,7 +105,7 @@ void CTxMemPool::clear()
     ++nTransactionsUpdated;
 }
 
-void CTxMemPool::check(CTxMemPool::CoinLookupFunc fnLookup) const
+void CTxMemPool::check(CCoinsViewCache *pcoins) const
 {
     if (!fSanityCheck)
         return;
@@ -121,7 +121,7 @@ void CTxMemPool::check(CTxMemPool::CoinLookupFunc fnLookup) const
             if (it2 != mapTx.end()) {
                 assert(it2->second.vout.size() > txin.prevout.n && !it2->second.vout[txin.prevout.n].IsNull());
             } else {
-                CCoins &coins = (*fnLookup)(txin.prevout.hash);
+                CCoins &coins = pcoins->GetCoins(txin.prevout.hash);
                 assert(coins.IsAvailable(txin.prevout.n));
             }
             // Check whether its inputs are marked in mapNextTx.
@@ -160,3 +160,21 @@ bool CTxMemPool::lookup(uint256 hash, CTransaction& result) const
     result = i->second;
     return true;
 }
+
+CCoinsViewMemPool::CCoinsViewMemPool(CCoinsView &baseIn, CTxMemPool &mempoolIn) : CCoinsViewBacked(baseIn), mempool(mempoolIn) { }
+
+bool CCoinsViewMemPool::GetCoins(const uint256 &txid, CCoins &coins) {
+    if (base->GetCoins(txid, coins))
+        return true;
+    CTransaction tx;
+    if (mempool.lookup(txid, tx)) {
+        coins = CCoins(tx, MEMPOOL_HEIGHT);
+        return true;
+    }
+    return false;
+}
+
+bool CCoinsViewMemPool::HaveCoins(const uint256 &txid) {
+    return mempool.exists(txid) || base->HaveCoins(txid);
+}
+
diff --git a/src/txmempool.h b/src/txmempool.h
index d5a7832ff7..57b92789fb 100644
--- a/src/txmempool.h
+++ b/src/txmempool.h
@@ -5,9 +5,13 @@
 #ifndef BITCOIN_TXMEMPOOL_H
 #define BITCOIN_TXMEMPOOL_H
 
+#include "coins.h"
 #include "core.h"
 #include "sync.h"
 
+/** Fake height value used in CCoins to signify they are only in the memory pool (since 0.8) */
+static const unsigned int MEMPOOL_HEIGHT = 0x7FFFFFFF;
+
 /*
  * CTxMemPool stores valid-according-to-the-current-best-chain
  * transactions that may be included in the next block.
@@ -37,8 +41,7 @@ public:
      * all inputs are in the mapNextTx array). If sanity-checking is turned off,
      * check does nothing.
      */
-    typedef CCoins& (*CoinLookupFunc)(const uint256&);
-    void check(CoinLookupFunc fnLookup) const;
+    void check(CCoinsViewCache *pcoins) const;
     void setSanityCheck(bool _fSanityCheck) { fSanityCheck = _fSanityCheck; }
 
     bool addUnchecked(const uint256& hash, const CTransaction &tx);
@@ -65,4 +68,17 @@ public:
     bool lookup(uint256 hash, CTransaction& result) const;
 };
 
+/** CCoinsView that brings transactions from a memorypool into view.
+    It does not check for spendings by memory pool transactions. */
+class CCoinsViewMemPool : public CCoinsViewBacked
+{
+protected:
+    CTxMemPool &mempool;
+
+public:
+    CCoinsViewMemPool(CCoinsView &baseIn, CTxMemPool &mempoolIn);
+    bool GetCoins(const uint256 &txid, CCoins &coins);
+    bool HaveCoins(const uint256 &txid);
+};
+
 #endif /* BITCOIN_TXMEMPOOL_H */