Merge pull request #5306

d227011 MOVEONLY: core/ -> primitives/ (Luke Dashjr)

4 files changed, 716 insertions, 0 deletions

diff --git a/src/primitives/block.cpp b/src/primitives/block.cpp
new file mode 100644
index 0000000000..225bb80be8
--- /dev/null
+++ b/src/primitives/block.cpp
@@ -0,0 +1,130 @@
+// Copyright (c) 2009-2010 Satoshi Nakamoto
+// Copyright (c) 2009-2014 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 "primitives/block.h"
+
+#include "hash.h"
+#include "tinyformat.h"
+#include "utilstrencodings.h"
+
+uint256 CBlockHeader::GetHash() const
+{
+    return Hash(BEGIN(nVersion), END(nNonce));
+}
+
+uint256 CBlock::BuildMerkleTree(bool* fMutated) const
+{
+    /* WARNING! If you're reading this because you're learning about crypto
+       and/or designing a new system that will use merkle trees, keep in mind
+       that the following merkle tree algorithm has a serious flaw related to
+       duplicate txids, resulting in a vulnerability (CVE-2012-2459).
+
+       The reason is that if the number of hashes in the list at a given time
+       is odd, the last one is duplicated before computing the next level (which
+       is unusual in Merkle trees). This results in certain sequences of
+       transactions leading to the same merkle root. For example, these two
+       trees:
+
+                    A               A
+                  /  \            /   \
+                B     C         B       C
+               / \    |        / \     / \
+              D   E   F       D   E   F   F
+             / \ / \ / \     / \ / \ / \ / \
+             1 2 3 4 5 6     1 2 3 4 5 6 5 6
+
+       for transaction lists [1,2,3,4,5,6] and [1,2,3,4,5,6,5,6] (where 5 and
+       6 are repeated) result in the same root hash A (because the hash of both
+       of (F) and (F,F) is C).
+
+       The vulnerability results from being able to send a block with such a
+       transaction list, with the same merkle root, and the same block hash as
+       the original without duplication, resulting in failed validation. If the
+       receiving node proceeds to mark that block as permanently invalid
+       however, it will fail to accept further unmodified (and thus potentially
+       valid) versions of the same block. We defend against this by detecting
+       the case where we would hash two identical hashes at the end of the list
+       together, and treating that identically to the block having an invalid
+       merkle root. Assuming no double-SHA256 collisions, this will detect all
+       known ways of changing the transactions without affecting the merkle
+       root.
+    */
+    vMerkleTree.clear();
+    vMerkleTree.reserve(vtx.size() * 2 + 16); // Safe upper bound for the number of total nodes.
+    for (std::vector<CTransaction>::const_iterator it(vtx.begin()); it != vtx.end(); ++it)
+        vMerkleTree.push_back(it->GetHash());
+    int j = 0;
+    bool mutated = false;
+    for (int nSize = vtx.size(); nSize > 1; nSize = (nSize + 1) / 2)
+    {
+        for (int i = 0; i < nSize; i += 2)
+        {
+            int i2 = std::min(i+1, nSize-1);
+            if (i2 == i + 1 && i2 + 1 == nSize && vMerkleTree[j+i] == vMerkleTree[j+i2]) {
+                // Two identical hashes at the end of the list at a particular level.
+                mutated = true;
+            }
+            vMerkleTree.push_back(Hash(BEGIN(vMerkleTree[j+i]),  END(vMerkleTree[j+i]),
+                                       BEGIN(vMerkleTree[j+i2]), END(vMerkleTree[j+i2])));
+        }
+        j += nSize;
+    }
+    if (fMutated) {
+        *fMutated = mutated;
+    }
+    return (vMerkleTree.empty() ? 0 : vMerkleTree.back());
+}
+
+std::vector<uint256> CBlock::GetMerkleBranch(int nIndex) const
+{
+    if (vMerkleTree.empty())
+        BuildMerkleTree();
+    std::vector<uint256> vMerkleBranch;
+    int j = 0;
+    for (int nSize = vtx.size(); nSize > 1; nSize = (nSize + 1) / 2)
+    {
+        int i = std::min(nIndex^1, nSize-1);
+        vMerkleBranch.push_back(vMerkleTree[j+i]);
+        nIndex >>= 1;
+        j += nSize;
+    }
+    return vMerkleBranch;
+}
+
+uint256 CBlock::CheckMerkleBranch(uint256 hash, const std::vector<uint256>& vMerkleBranch, int nIndex)
+{
+    if (nIndex == -1)
+        return 0;
+    for (std::vector<uint256>::const_iterator it(vMerkleBranch.begin()); it != vMerkleBranch.end(); ++it)
+    {
+        if (nIndex & 1)
+            hash = Hash(BEGIN(*it), END(*it), BEGIN(hash), END(hash));
+        else
+            hash = Hash(BEGIN(hash), END(hash), BEGIN(*it), END(*it));
+        nIndex >>= 1;
+    }
+    return hash;
+}
+
+std::string CBlock::ToString() const
+{
+    std::stringstream s;
+    s << strprintf("CBlock(hash=%s, ver=%d, hashPrevBlock=%s, hashMerkleRoot=%s, nTime=%u, nBits=%08x, nNonce=%u, vtx=%u)\n",
+        GetHash().ToString(),
+        nVersion,
+        hashPrevBlock.ToString(),
+        hashMerkleRoot.ToString(),
+        nTime, nBits, nNonce,
+        vtx.size());
+    for (unsigned int i = 0; i < vtx.size(); i++)
+    {
+        s << "  " << vtx[i].ToString() << "\n";
+    }
+    s << "  vMerkleTree: ";
+    for (unsigned int i = 0; i < vMerkleTree.size(); i++)
+        s << " " << vMerkleTree[i].ToString();
+    s << "\n";
+    return s.str();
+}
diff --git a/src/primitives/block.h b/src/primitives/block.h
new file mode 100644
index 0000000000..e663c91e84
--- /dev/null
+++ b/src/primitives/block.h
@@ -0,0 +1,168 @@
+// 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_PRIMITIVES_BLOCK_H
+#define BITCOIN_PRIMITIVES_BLOCK_H
+
+#include "primitives/transaction.h"
+#include "serialize.h"
+#include "uint256.h"
+
+/** 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
+ * to everyone and the block is added to the block chain.  The first transaction
+ * in the block is a special one that creates a new coin owned by the creator
+ * of the block.
+ */
+class CBlockHeader
+{
+public:
+    // header
+    static const int32_t CURRENT_VERSION=2;
+    int32_t nVersion;
+    uint256 hashPrevBlock;
+    uint256 hashMerkleRoot;
+    uint32_t nTime;
+    uint32_t nBits;
+    uint32_t nNonce;
+
+    CBlockHeader()
+    {
+        SetNull();
+    }
+
+    ADD_SERIALIZE_METHODS;
+
+    template <typename Stream, typename Operation>
+    inline void SerializationOp(Stream& s, Operation ser_action, int nType, int nVersion) {
+        READWRITE(this->nVersion);
+        nVersion = this->nVersion;
+        READWRITE(hashPrevBlock);
+        READWRITE(hashMerkleRoot);
+        READWRITE(nTime);
+        READWRITE(nBits);
+        READWRITE(nNonce);
+    }
+
+    void SetNull()
+    {
+        nVersion = CBlockHeader::CURRENT_VERSION;
+        hashPrevBlock = 0;
+        hashMerkleRoot = 0;
+        nTime = 0;
+        nBits = 0;
+        nNonce = 0;
+    }
+
+    bool IsNull() const
+    {
+        return (nBits == 0);
+    }
+
+    uint256 GetHash() const;
+
+    int64_t GetBlockTime() const
+    {
+        return (int64_t)nTime;
+    }
+};
+
+
+class CBlock : public CBlockHeader
+{
+public:
+    // network and disk
+    std::vector<CTransaction> vtx;
+
+    // memory only
+    mutable std::vector<uint256> vMerkleTree;
+
+    CBlock()
+    {
+        SetNull();
+    }
+
+    CBlock(const CBlockHeader &header)
+    {
+        SetNull();
+        *((CBlockHeader*)this) = header;
+    }
+
+    ADD_SERIALIZE_METHODS;
+
+    template <typename Stream, typename Operation>
+    inline void SerializationOp(Stream& s, Operation ser_action, int nType, int nVersion) {
+        READWRITE(*(CBlockHeader*)this);
+        READWRITE(vtx);
+    }
+
+    void SetNull()
+    {
+        CBlockHeader::SetNull();
+        vtx.clear();
+        vMerkleTree.clear();
+    }
+
+    CBlockHeader GetBlockHeader() const
+    {
+        CBlockHeader block;
+        block.nVersion       = nVersion;
+        block.hashPrevBlock  = hashPrevBlock;
+        block.hashMerkleRoot = hashMerkleRoot;
+        block.nTime          = nTime;
+        block.nBits          = nBits;
+        block.nNonce         = nNonce;
+        return block;
+    }
+
+    // Build the in-memory merkle tree for this block and return the merkle root.
+    // If non-NULL, *mutated is set to whether mutation was detected in the merkle
+    // tree (a duplication of transactions in the block leading to an identical
+    // merkle root).
+    uint256 BuildMerkleTree(bool* mutated = NULL) const;
+
+    std::vector<uint256> GetMerkleBranch(int nIndex) const;
+    static uint256 CheckMerkleBranch(uint256 hash, const std::vector<uint256>& vMerkleBranch, int nIndex);
+    std::string ToString() const;
+};
+
+
+/** Describes a place in the block chain to another node such that if the
+ * other node doesn't have the same branch, it can find a recent common trunk.
+ * The further back it is, the further before the fork it may be.
+ */
+struct CBlockLocator
+{
+    std::vector<uint256> vHave;
+
+    CBlockLocator() {}
+
+    CBlockLocator(const std::vector<uint256>& vHaveIn)
+    {
+        vHave = vHaveIn;
+    }
+
+    ADD_SERIALIZE_METHODS;
+
+    template <typename Stream, typename Operation>
+    inline void SerializationOp(Stream& s, Operation ser_action, int nType, int nVersion) {
+        if (!(nType & SER_GETHASH))
+            READWRITE(nVersion);
+        READWRITE(vHave);
+    }
+
+    void SetNull()
+    {
+        vHave.clear();
+    }
+
+    bool IsNull()
+    {
+        return vHave.empty();
+    }
+};
+
+#endif // BITCOIN_PRIMITIVES_BLOCK_H
diff --git a/src/primitives/transaction.cpp b/src/primitives/transaction.cpp
new file mode 100644
index 0000000000..336151905c
--- /dev/null
+++ b/src/primitives/transaction.cpp
@@ -0,0 +1,142 @@
+// Copyright (c) 2009-2010 Satoshi Nakamoto
+// Copyright (c) 2009-2014 The Bitcoin developers
+// Distributed under the MIT software license, see the accompanying
+// file COPYING or http://www.opensource.org/licenses/mit-license.php.
+
+#include "primitives/transaction.h"
+
+#include "hash.h"
+#include "tinyformat.h"
+#include "utilstrencodings.h"
+
+std::string COutPoint::ToString() const
+{
+    return strprintf("COutPoint(%s, %u)", hash.ToString().substr(0,10), n);
+}
+
+CTxIn::CTxIn(COutPoint prevoutIn, CScript scriptSigIn, uint32_t nSequenceIn)
+{
+    prevout = prevoutIn;
+    scriptSig = scriptSigIn;
+    nSequence = nSequenceIn;
+}
+
+CTxIn::CTxIn(uint256 hashPrevTx, uint32_t nOut, CScript scriptSigIn, uint32_t nSequenceIn)
+{
+    prevout = COutPoint(hashPrevTx, nOut);
+    scriptSig = scriptSigIn;
+    nSequence = nSequenceIn;
+}
+
+std::string CTxIn::ToString() const
+{
+    std::string str;
+    str += "CTxIn(";
+    str += prevout.ToString();
+    if (prevout.IsNull())
+        str += strprintf(", coinbase %s", HexStr(scriptSig));
+    else
+        str += strprintf(", scriptSig=%s", scriptSig.ToString().substr(0,24));
+    if (nSequence != std::numeric_limits<unsigned int>::max())
+        str += strprintf(", nSequence=%u", nSequence);
+    str += ")";
+    return str;
+}
+
+CTxOut::CTxOut(const CAmount& nValueIn, CScript scriptPubKeyIn)
+{
+    nValue = nValueIn;
+    scriptPubKey = scriptPubKeyIn;
+}
+
+uint256 CTxOut::GetHash() const
+{
+    return SerializeHash(*this);
+}
+
+std::string CTxOut::ToString() const
+{
+    return strprintf("CTxOut(nValue=%d.%08d, scriptPubKey=%s)", nValue / COIN, nValue % COIN, scriptPubKey.ToString().substr(0,30));
+}
+
+CMutableTransaction::CMutableTransaction() : nVersion(CTransaction::CURRENT_VERSION), nLockTime(0) {}
+CMutableTransaction::CMutableTransaction(const CTransaction& tx) : nVersion(tx.nVersion), vin(tx.vin), vout(tx.vout), nLockTime(tx.nLockTime) {}
+
+uint256 CMutableTransaction::GetHash() const
+{
+    return SerializeHash(*this);
+}
+
+void CTransaction::UpdateHash() const
+{
+    *const_cast<uint256*>(&hash) = SerializeHash(*this);
+}
+
+CTransaction::CTransaction() : hash(0), nVersion(CTransaction::CURRENT_VERSION), vin(), vout(), nLockTime(0) { }
+
+CTransaction::CTransaction(const CMutableTransaction &tx) : nVersion(tx.nVersion), vin(tx.vin), vout(tx.vout), nLockTime(tx.nLockTime) {
+    UpdateHash();
+}
+
+CTransaction& CTransaction::operator=(const CTransaction &tx) {
+    *const_cast<int*>(&nVersion) = tx.nVersion;
+    *const_cast<std::vector<CTxIn>*>(&vin) = tx.vin;
+    *const_cast<std::vector<CTxOut>*>(&vout) = tx.vout;
+    *const_cast<unsigned int*>(&nLockTime) = tx.nLockTime;
+    *const_cast<uint256*>(&hash) = tx.hash;
+    return *this;
+}
+
+CAmount CTransaction::GetValueOut() const
+{
+    CAmount nValueOut = 0;
+    for (std::vector<CTxOut>::const_iterator it(vout.begin()); it != vout.end(); ++it)
+    {
+        nValueOut += it->nValue;
+        if (!MoneyRange(it->nValue) || !MoneyRange(nValueOut))
+            throw std::runtime_error("CTransaction::GetValueOut() : value out of range");
+    }
+    return nValueOut;
+}
+
+double CTransaction::ComputePriority(double dPriorityInputs, unsigned int nTxSize) const
+{
+    nTxSize = CalculateModifiedSize(nTxSize);
+    if (nTxSize == 0) return 0.0;
+
+    return dPriorityInputs / nTxSize;
+}
+
+unsigned int CTransaction::CalculateModifiedSize(unsigned int nTxSize) const
+{
+    // In order to avoid disincentivizing cleaning up the UTXO set we don't count
+    // the constant overhead for each txin and up to 110 bytes of scriptSig (which
+    // is enough to cover a compressed pubkey p2sh redemption) for priority.
+    // Providing any more cleanup incentive than making additional inputs free would
+    // risk encouraging people to create junk outputs to redeem later.
+    if (nTxSize == 0)
+        nTxSize = ::GetSerializeSize(*this, SER_NETWORK, PROTOCOL_VERSION);
+    for (std::vector<CTxIn>::const_iterator it(vin.begin()); it != vin.end(); ++it)
+    {
+        unsigned int offset = 41U + std::min(110U, (unsigned int)it->scriptSig.size());
+        if (nTxSize > offset)
+            nTxSize -= offset;
+    }
+    return nTxSize;
+}
+
+std::string CTransaction::ToString() const
+{
+    std::string str;
+    str += strprintf("CTransaction(hash=%s, ver=%d, vin.size=%u, vout.size=%u, nLockTime=%u)\n",
+        GetHash().ToString().substr(0,10),
+        nVersion,
+        vin.size(),
+        vout.size(),
+        nLockTime);
+    for (unsigned int i = 0; i < vin.size(); i++)
+        str += "    " + vin[i].ToString() + "\n";
+    for (unsigned int i = 0; i < vout.size(); i++)
+        str += "    " + vout[i].ToString() + "\n";
+    return str;
+}
diff --git a/src/primitives/transaction.h b/src/primitives/transaction.h
new file mode 100644
index 0000000000..a7a1e013ed
--- /dev/null
+++ b/src/primitives/transaction.h
@@ -0,0 +1,276 @@
+// Copyright (c) 2009-2010 Satoshi Nakamoto
+// Copyright (c) 2009-2014 The Bitcoin developers
+// Distributed under the MIT software license, see the accompanying
+// file COPYING or http://www.opensource.org/licenses/mit-license.php.
+
+#ifndef BITCOIN_PRIMITIVES_TRANSACTION_H
+#define BITCOIN_PRIMITIVES_TRANSACTION_H
+
+#include "amount.h"
+#include "script/script.h"
+#include "serialize.h"
+#include "uint256.h"
+
+/** An outpoint - a combination of a transaction hash and an index n into its vout */
+class COutPoint
+{
+public:
+    uint256 hash;
+    uint32_t n;
+
+    COutPoint() { SetNull(); }
+    COutPoint(uint256 hashIn, uint32_t nIn) { hash = hashIn; n = nIn; }
+
+    ADD_SERIALIZE_METHODS;
+
+    template <typename Stream, typename Operation>
+    inline void SerializationOp(Stream& s, Operation ser_action, int nType, int nVersion) {
+        READWRITE(FLATDATA(*this));
+    }
+
+    void SetNull() { hash = 0; n = (uint32_t) -1; }
+    bool IsNull() const { return (hash == 0 && n == (uint32_t) -1); }
+
+    friend bool operator<(const COutPoint& a, const COutPoint& b)
+    {
+        return (a.hash < b.hash || (a.hash == b.hash && a.n < b.n));
+    }
+
+    friend bool operator==(const COutPoint& a, const COutPoint& b)
+    {
+        return (a.hash == b.hash && a.n == b.n);
+    }
+
+    friend bool operator!=(const COutPoint& a, const COutPoint& b)
+    {
+        return !(a == b);
+    }
+
+    std::string ToString() const;
+};
+
+/** An input of a transaction.  It contains the location of the previous
+ * transaction's output that it claims and a signature that matches the
+ * output's public key.
+ */
+class CTxIn
+{
+public:
+    COutPoint prevout;
+    CScript scriptSig;
+    uint32_t nSequence;
+
+    CTxIn()
+    {
+        nSequence = std::numeric_limits<unsigned int>::max();
+    }
+
+    explicit CTxIn(COutPoint prevoutIn, CScript scriptSigIn=CScript(), uint32_t nSequenceIn=std::numeric_limits<unsigned int>::max());
+    CTxIn(uint256 hashPrevTx, uint32_t nOut, CScript scriptSigIn=CScript(), uint32_t nSequenceIn=std::numeric_limits<uint32_t>::max());
+
+    ADD_SERIALIZE_METHODS;
+
+    template <typename Stream, typename Operation>
+    inline void SerializationOp(Stream& s, Operation ser_action, int nType, int nVersion) {
+        READWRITE(prevout);
+        READWRITE(scriptSig);
+        READWRITE(nSequence);
+    }
+
+    bool IsFinal() const
+    {
+        return (nSequence == std::numeric_limits<uint32_t>::max());
+    }
+
+    friend bool operator==(const CTxIn& a, const CTxIn& b)
+    {
+        return (a.prevout   == b.prevout &&
+                a.scriptSig == b.scriptSig &&
+                a.nSequence == b.nSequence);
+    }
+
+    friend bool operator!=(const CTxIn& a, const CTxIn& b)
+    {
+        return !(a == b);
+    }
+
+    std::string ToString() const;
+};
+
+/** An output of a transaction.  It contains the public key that the next input
+ * must be able to sign with to claim it.
+ */
+class CTxOut
+{
+public:
+    CAmount nValue;
+    CScript scriptPubKey;
+
+    CTxOut()
+    {
+        SetNull();
+    }
+
+    CTxOut(const CAmount& nValueIn, CScript scriptPubKeyIn);
+
+    ADD_SERIALIZE_METHODS;
+
+    template <typename Stream, typename Operation>
+    inline void SerializationOp(Stream& s, Operation ser_action, int nType, int nVersion) {
+        READWRITE(nValue);
+        READWRITE(scriptPubKey);
+    }
+
+    void SetNull()
+    {
+        nValue = -1;
+        scriptPubKey.clear();
+    }
+
+    bool IsNull() const
+    {
+        return (nValue == -1);
+    }
+
+    uint256 GetHash() const;
+
+    bool IsDust(CFeeRate minRelayTxFee) const
+    {
+        // "Dust" is defined in terms of CTransaction::minRelayTxFee,
+        // which has units satoshis-per-kilobyte.
+        // If you'd pay more than 1/3 in fees
+        // to spend something, then we consider it dust.
+        // A typical txout is 34 bytes big, and will
+        // need a CTxIn of at least 148 bytes to spend:
+        // so dust is a txout less than 546 satoshis 
+        // with default minRelayTxFee.
+        size_t nSize = GetSerializeSize(SER_DISK,0)+148u;
+        return (nValue < 3*minRelayTxFee.GetFee(nSize));
+    }
+
+    friend bool operator==(const CTxOut& a, const CTxOut& b)
+    {
+        return (a.nValue       == b.nValue &&
+                a.scriptPubKey == b.scriptPubKey);
+    }
+
+    friend bool operator!=(const CTxOut& a, const CTxOut& b)
+    {
+        return !(a == b);
+    }
+
+    std::string ToString() const;
+};
+
+struct CMutableTransaction;
+
+/** The basic transaction that is broadcasted on the network and contained in
+ * blocks.  A transaction can contain multiple inputs and outputs.
+ */
+class CTransaction
+{
+private:
+    /** Memory only. */
+    const uint256 hash;
+    void UpdateHash() const;
+
+public:
+    static const int32_t CURRENT_VERSION=1;
+
+    // The local variables are made const to prevent unintended modification
+    // without updating the cached hash value. However, CTransaction is not
+    // actually immutable; deserialization and assignment are implemented,
+    // and bypass the constness. This is safe, as they update the entire
+    // structure, including the hash.
+    const int32_t nVersion;
+    const std::vector<CTxIn> vin;
+    const std::vector<CTxOut> vout;
+    const uint32_t nLockTime;
+
+    /** Construct a CTransaction that qualifies as IsNull() */
+    CTransaction();
+
+    /** Convert a CMutableTransaction into a CTransaction. */
+    CTransaction(const CMutableTransaction &tx);
+
+    CTransaction& operator=(const CTransaction& tx);
+
+    ADD_SERIALIZE_METHODS;
+
+    template <typename Stream, typename Operation>
+    inline void SerializationOp(Stream& s, Operation ser_action, int nType, int nVersion) {
+        READWRITE(*const_cast<int32_t*>(&this->nVersion));
+        nVersion = this->nVersion;
+        READWRITE(*const_cast<std::vector<CTxIn>*>(&vin));
+        READWRITE(*const_cast<std::vector<CTxOut>*>(&vout));
+        READWRITE(*const_cast<uint32_t*>(&nLockTime));
+        if (ser_action.ForRead())
+            UpdateHash();
+    }
+
+    bool IsNull() const {
+        return vin.empty() && vout.empty();
+    }
+
+    const uint256& GetHash() const {
+        return hash;
+    }
+
+    // Return sum of txouts.
+    CAmount GetValueOut() const;
+    // GetValueIn() is a method on CCoinsViewCache, because
+    // inputs must be known to compute value in.
+
+    // Compute priority, given priority of inputs and (optionally) tx size
+    double ComputePriority(double dPriorityInputs, unsigned int nTxSize=0) const;
+
+    // Compute modified tx size for priority calculation (optionally given tx size)
+    unsigned int CalculateModifiedSize(unsigned int nTxSize=0) const;
+
+    bool IsCoinBase() const
+    {
+        return (vin.size() == 1 && vin[0].prevout.IsNull());
+    }
+
+    friend bool operator==(const CTransaction& a, const CTransaction& b)
+    {
+        return a.hash == b.hash;
+    }
+
+    friend bool operator!=(const CTransaction& a, const CTransaction& b)
+    {
+        return a.hash != b.hash;
+    }
+
+    std::string ToString() const;
+};
+
+/** A mutable version of CTransaction. */
+struct CMutableTransaction
+{
+    int32_t nVersion;
+    std::vector<CTxIn> vin;
+    std::vector<CTxOut> vout;
+    uint32_t nLockTime;
+
+    CMutableTransaction();
+    CMutableTransaction(const CTransaction& tx);
+
+    ADD_SERIALIZE_METHODS;
+
+    template <typename Stream, typename Operation>
+    inline void SerializationOp(Stream& s, Operation ser_action, int nType, int nVersion) {
+        READWRITE(this->nVersion);
+        nVersion = this->nVersion;
+        READWRITE(vin);
+        READWRITE(vout);
+        READWRITE(nLockTime);
+    }
+
+    /** Compute the hash of this CMutableTransaction. This is computed on the
+     * fly, as opposed to GetHash() in CTransaction, which uses a cached result.
+     */
+    uint256 GetHash() const;
+};
+
+#endif // BITCOIN_PRIMITIVES_TRANSACTION_H