transaction.h

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// Copyright (c) 2009-2010 Satoshi Nakamoto
// Copyright (c) 2009-2016 The Bitcoin Core developers
// Copyright (c) 2017-2019 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 <consensus/amount.h>
#include <feerate.h>
#include <primitives/txid.h>
#include <script/script.h>
#include <serialize.h>
 
class COutPoint {
private:
    TxId txid;
    uint32_t n;
 
public:
    static constexpr uint32_t NULL_INDEX = std::numeric_limits<uint32_t>::max();
 
    COutPoint() : txid(), n(NULL_INDEX) {}
    COutPoint(TxId txidIn, uint32_t nIn) : txid(txidIn), n(nIn) {}
 
    SERIALIZE_METHODS(COutPoint, obj) { READWRITE(obj.txid, obj.n); }
 
    bool IsNull() const { return txid.IsNull() && n == NULL_INDEX; }
 
    const TxId &GetTxId() const { return txid; }
    uint32_t GetN() const { return n; }
 
    friend bool operator<(const COutPoint &a, const COutPoint &b) {
        int cmp = a.txid.Compare(b.txid);
        return cmp < 0 || (cmp == 0 && a.n < b.n);
    }
 
    friend bool operator==(const COutPoint &a, const COutPoint &b) {
        return (a.txid == b.txid && a.n == b.n);
    }
 
    friend bool operator!=(const COutPoint &a, const COutPoint &b) {
        return !(a == b);
    }
 
    std::string ToString() const;
};
 
class CTxIn {
public:
    COutPoint prevout;
    CScript scriptSig;
    uint32_t nSequence;
 
    static const uint32_t SEQUENCE_FINAL = 0xffffffff;
 
    /* Below flags apply in the context of BIP 68*/
    static const uint32_t SEQUENCE_LOCKTIME_DISABLE_FLAG = (1U << 31);
 
    static const uint32_t SEQUENCE_LOCKTIME_TYPE_FLAG = (1 << 22);
 
    static const uint32_t SEQUENCE_LOCKTIME_MASK = 0x0000ffff;
 
    static const int SEQUENCE_LOCKTIME_GRANULARITY = 9;
 
    CTxIn() { nSequence = SEQUENCE_FINAL; }
 
    explicit CTxIn(COutPoint prevoutIn, CScript scriptSigIn = CScript(),
                   uint32_t nSequenceIn = SEQUENCE_FINAL)
        : prevout(prevoutIn), scriptSig(scriptSigIn), nSequence(nSequenceIn) {}
    CTxIn(TxId prevTxId, uint32_t nOut, CScript scriptSigIn = CScript(),
          uint32_t nSequenceIn = SEQUENCE_FINAL)
        : CTxIn(COutPoint(prevTxId, nOut), scriptSigIn, nSequenceIn) {}
 
    SERIALIZE_METHODS(CTxIn, obj) {
        READWRITE(obj.prevout, obj.scriptSig, obj.nSequence);
    }
 
    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;
};
 
class CTxOut {
public:
    Amount nValue;
    CScript scriptPubKey;
 
    CTxOut() { SetNull(); }
 
    CTxOut(Amount nValueIn, CScript scriptPubKeyIn)
        : nValue(nValueIn), scriptPubKey(scriptPubKeyIn) {}
 
    SERIALIZE_METHODS(CTxOut, obj) { READWRITE(obj.nValue, obj.scriptPubKey); }
 
    void SetNull() {
        nValue = -SATOSHI;
        scriptPubKey.clear();
    }
 
    bool IsNull() const { return nValue == -SATOSHI; }
 
    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;
};
 
class CMutableTransaction;
 
template <typename Stream, typename TxType>
inline void UnserializeTransaction(TxType &tx, Stream &s) {
    s >> tx.nVersion;
    tx.vin.clear();
    tx.vout.clear();
    /* Try to read the vin. In case the dummy is there, this will be read as an
     * empty vector. */
    s >> tx.vin;
    /* We read a non-empty vin. Assume a normal vout follows. */
    s >> tx.vout;
    s >> tx.nLockTime;
}
 
template <typename Stream, typename TxType>
inline void SerializeTransaction(const TxType &tx, Stream &s) {
    s << tx.nVersion;
    s << tx.vin;
    s << tx.vout;
    s << tx.nLockTime;
}
 
class CTransaction {
public:
    // Default transaction version.
    static constexpr int32_t CURRENT_VERSION = 2;
 
    // Consensus: Valid min/max for nVersion, enforced as a consensus rule after
    // Wellington.
    static constexpr int32_t MIN_VERSION = 1, MAX_VERSION = 2;
 
    // 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 std::vector<CTxIn> vin;
    const std::vector<CTxOut> vout;
    const int32_t nVersion;
    const uint32_t nLockTime;
 
private:
    const uint256 hash;
 
    uint256 ComputeHash() const;
 
public:
    CTransaction();
 
    explicit CTransaction(const CMutableTransaction &tx);
    explicit CTransaction(CMutableTransaction &&tx);
 
    template <typename Stream> inline void Serialize(Stream &s) const {
        SerializeTransaction(*this, s);
    }
 
    template <typename Stream>
    CTransaction(deserialize_type, Stream &s)
        : CTransaction(CMutableTransaction(deserialize, s)) {}
 
    bool IsNull() const { return vin.empty() && vout.empty(); }
 
    const TxId GetId() const { return TxId(hash); }
    const TxHash GetHash() const { return TxHash(hash); }
 
    // Return sum of txouts.
    Amount GetValueOut() const;
 
    unsigned int GetTotalSize() const;
 
    bool IsCoinBase() const {
        return (vin.size() == 1 && vin[0].prevout.IsNull());
    }
 
    friend bool operator==(const CTransaction &a, const CTransaction &b) {
        return a.GetHash() == b.GetHash();
    }
 
    friend bool operator!=(const CTransaction &a, const CTransaction &b) {
        return !(a == b);
    }
 
    std::string ToString() const;
};
#if defined(__x86_64__)
static_assert(sizeof(CTransaction) == 88,
              "sizeof CTransaction is expected to be 88 bytes");
#endif
 
class CMutableTransaction {
public:
    std::vector<CTxIn> vin;
    std::vector<CTxOut> vout;
    int32_t nVersion;
    uint32_t nLockTime;
 
    CMutableTransaction();
    explicit CMutableTransaction(const CTransaction &tx);
 
    template <typename Stream> inline void Serialize(Stream &s) const {
        SerializeTransaction(*this, s);
    }
 
    template <typename Stream> inline void Unserialize(Stream &s) {
        UnserializeTransaction(*this, s);
    }
 
    template <typename Stream>
    CMutableTransaction(deserialize_type, Stream &s) {
        Unserialize(s);
    }
 
    TxId GetId() const;
    TxHash GetHash() const;
 
    friend bool operator==(const CMutableTransaction &a,
                           const CMutableTransaction &b) {
        return a.GetHash() == b.GetHash();
    }
};
#if defined(__x86_64__)
static_assert(sizeof(CMutableTransaction) == 56,
              "sizeof CMutableTransaction is expected to be 56 bytes");
#endif
 
using CTransactionRef = std::shared_ptr<const CTransaction>;
static inline CTransactionRef MakeTransactionRef() {
    return std::make_shared<const CTransaction>();
}
template <typename Tx>
static inline CTransactionRef MakeTransactionRef(Tx &&txIn) {
    return std::make_shared<const CTransaction>(std::forward<Tx>(txIn));
}
 
struct PrecomputedTransactionData {
    uint256 hashPrevouts, hashSequence, hashOutputs;
 
    PrecomputedTransactionData()
        : hashPrevouts(), hashSequence(), hashOutputs() {}
 
    PrecomputedTransactionData(const PrecomputedTransactionData &txdata) =
        default;
    PrecomputedTransactionData &
    operator=(const PrecomputedTransactionData &txdata) = default;
 
    template <class T> explicit PrecomputedTransactionData(const T &tx);
};
 
#endif // BITCOIN_PRIMITIVES_TRANSACTION_H