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// Copyright (c) 2009-2010 Satoshi Nakamoto
// Copyright (c) 2009-2015 The Bitcoin Core 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"
static const int SERIALIZE_TRANSACTION_NO_WITNESS = 0x40000000;
static const int WITNESS_SCALE_FACTOR = 4;
/** 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(hash);
READWRITE(n);
}
void SetNull() { hash.SetNull(); n = (uint32_t) -1; }
bool IsNull() const { return (hash.IsNull() && n == (uint32_t) -1); }
friend bool operator<(const COutPoint& a, const COutPoint& b)
{
int cmp = a.hash.Compare(b.hash);
return cmp < 0 || (cmp == 0 && 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;
/* Setting nSequence to this value for every input in a transaction
* disables nLockTime. */
static const uint32_t SEQUENCE_FINAL = 0xffffffff;
/* Below flags apply in the context of BIP 68*/
/* If this flag set, CTxIn::nSequence is NOT interpreted as a
* relative lock-time. */
static const uint32_t SEQUENCE_LOCKTIME_DISABLE_FLAG = (1 << 31);
/* If CTxIn::nSequence encodes a relative lock-time and this flag
* is set, the relative lock-time has units of 512 seconds,
* otherwise it specifies blocks with a granularity of 1. */
static const uint32_t SEQUENCE_LOCKTIME_TYPE_FLAG = (1 << 22);
/* If CTxIn::nSequence encodes a relative lock-time, this mask is
* applied to extract that lock-time from the sequence field. */
static const uint32_t SEQUENCE_LOCKTIME_MASK = 0x0000ffff;
/* In order to use the same number of bits to encode roughly the
* same wall-clock duration, and because blocks are naturally
* limited to occur every 600s on average, the minimum granularity
* for time-based relative lock-time is fixed at 512 seconds.
* Converting from CTxIn::nSequence to seconds is performed by
* multiplying by 512 = 2^9, or equivalently shifting up by
* 9 bits. */
static const int SEQUENCE_LOCKTIME_GRANULARITY = 9;
CTxIn()
{
nSequence = SEQUENCE_FINAL;
}
explicit CTxIn(COutPoint prevoutIn, CScript scriptSigIn=CScript(), uint32_t nSequenceIn=SEQUENCE_FINAL);
CTxIn(uint256 hashPrevTx, uint32_t nOut, CScript scriptSigIn=CScript(), uint32_t nSequenceIn=SEQUENCE_FINAL);
ADD_SERIALIZE_METHODS;
template <typename Stream, typename Operation>
inline void SerializationOp(Stream& s, Operation ser_action, int nType, int nVersion) {
READWRITE(prevout);
READWRITE(*(CScriptBase*)(&scriptSig));
READWRITE(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;
};
/** 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(*(CScriptBase*)(&scriptPubKey));
}
void SetNull()
{
nValue = -1;
scriptPubKey.clear();
}
bool IsNull() const
{
return (nValue == -1);
}
uint256 GetHash() const;
CAmount GetDustThreshold(const 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 spendable non-segwit txout is 34 bytes big, and will
// need a CTxIn of at least 148 bytes to spend:
// so dust is a spendable txout less than
// 546*minRelayTxFee/1000 (in satoshis).
// A typical spendable segwit txout is 31 bytes big, and will
// need a CTxIn of at least 67 bytes to spend:
// so dust is a spendable txout less than
// 294*minRelayTxFee/1000 (in satoshis).
if (scriptPubKey.IsUnspendable())
return 0;
size_t nSize = GetSerializeSize(SER_DISK, 0);
int witnessversion = 0;
std::vector<unsigned char> witnessprogram;
if (scriptPubKey.IsWitnessProgram(witnessversion, witnessprogram)) {
// sum the sizes of the parts of a transaction input
// with 75% segwit discount applied to the script size.
nSize += (32 + 4 + 1 + (107 / WITNESS_SCALE_FACTOR) + 4);
} else {
nSize += (32 + 4 + 1 + 107 + 4); // the 148 mentioned above
}
return 3 * minRelayTxFee.GetFee(nSize);
}
bool IsDust(const CFeeRate &minRelayTxFee) const
{
return (nValue < GetDustThreshold(minRelayTxFee));
}
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 CTxInWitness
{
public:
CScriptWitness scriptWitness;
ADD_SERIALIZE_METHODS;
template <typename Stream, typename Operation>
inline void SerializationOp(Stream& s, Operation ser_action, int nType, int nVersion)
{
READWRITE(scriptWitness.stack);
}
bool IsNull() const { return scriptWitness.IsNull(); }
CTxInWitness() { }
};
class CTxWitness
{
public:
/** In case vtxinwit is missing, all entries are treated as if they were empty CTxInWitnesses */
std::vector<CTxInWitness> vtxinwit;
ADD_SERIALIZE_METHODS;
bool IsEmpty() const { return vtxinwit.empty(); }
bool IsNull() const
{
for (size_t n = 0; n < vtxinwit.size(); n++) {
if (!vtxinwit[n].IsNull()) {
return false;
}
}
return true;
}
void SetNull()
{
vtxinwit.clear();
}
template <typename Stream, typename Operation>
inline void SerializationOp(Stream& s, Operation ser_action, int nType, int nVersion)
{
for (size_t n = 0; n < vtxinwit.size(); n++) {
READWRITE(vtxinwit[n]);
}
if (IsNull()) {
/* It's illegal to encode a witness when all vtxinwit entries are empty. */
throw std::ios_base::failure("Superfluous witness record");
}
}
};
struct CMutableTransaction;
/**
* Basic transaction serialization format:
* - int32_t nVersion
* - std::vector<CTxIn> vin
* - std::vector<CTxOut> vout
* - uint32_t nLockTime
*
* Extended transaction serialization format:
* - int32_t nVersion
* - unsigned char dummy = 0x00
* - unsigned char flags (!= 0)
* - std::vector<CTxIn> vin
* - std::vector<CTxOut> vout
* - if (flags & 1):
* - CTxWitness wit;
* - uint32_t nLockTime
*/
template<typename Stream, typename Operation, typename TxType>
inline void SerializeTransaction(TxType& tx, Stream& s, Operation ser_action, int nType, int nVersion) {
READWRITE(*const_cast<int32_t*>(&tx.nVersion));
unsigned char flags = 0;
if (ser_action.ForRead()) {
const_cast<std::vector<CTxIn>*>(&tx.vin)->clear();
const_cast<std::vector<CTxOut>*>(&tx.vout)->clear();
const_cast<CTxWitness*>(&tx.wit)->SetNull();
/* Try to read the vin. In case the dummy is there, this will be read as an empty vector. */
READWRITE(*const_cast<std::vector<CTxIn>*>(&tx.vin));
if (tx.vin.size() == 0 && !(nVersion & SERIALIZE_TRANSACTION_NO_WITNESS)) {
/* We read a dummy or an empty vin. */
READWRITE(flags);
if (flags != 0) {
READWRITE(*const_cast<std::vector<CTxIn>*>(&tx.vin));
READWRITE(*const_cast<std::vector<CTxOut>*>(&tx.vout));
}
} else {
/* We read a non-empty vin. Assume a normal vout follows. */
READWRITE(*const_cast<std::vector<CTxOut>*>(&tx.vout));
}
if ((flags & 1) && !(nVersion & SERIALIZE_TRANSACTION_NO_WITNESS)) {
/* The witness flag is present, and we support witnesses. */
flags ^= 1;
const_cast<CTxWitness*>(&tx.wit)->vtxinwit.resize(tx.vin.size());
READWRITE(tx.wit);
}
if (flags) {
/* Unknown flag in the serialization */
throw std::ios_base::failure("Unknown transaction optional data");
}
} else {
// Consistency check
assert(tx.wit.vtxinwit.size() <= tx.vin.size());
if (!(nVersion & SERIALIZE_TRANSACTION_NO_WITNESS)) {
/* Check whether witnesses need to be serialized. */
if (!tx.wit.IsNull()) {
flags |= 1;
}
}
if (flags) {
/* Use extended format in case witnesses are to be serialized. */
std::vector<CTxIn> vinDummy;
READWRITE(vinDummy);
READWRITE(flags);
}
READWRITE(*const_cast<std::vector<CTxIn>*>(&tx.vin));
READWRITE(*const_cast<std::vector<CTxOut>*>(&tx.vout));
if (flags & 1) {
const_cast<CTxWitness*>(&tx.wit)->vtxinwit.resize(tx.vin.size());
READWRITE(tx.wit);
}
}
READWRITE(*const_cast<uint32_t*>(&tx.nLockTime));
}
/** 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;
public:
// Default transaction version.
static const int32_t CURRENT_VERSION=1;
// Changing the default transaction version requires a two step process: first
// adapting relay policy by bumping MAX_STANDARD_VERSION, and then later date
// bumping the default CURRENT_VERSION at which point both CURRENT_VERSION and
// MAX_STANDARD_VERSION will be equal.
static const int32_t MAX_STANDARD_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 int32_t nVersion;
const std::vector<CTxIn> vin;
const std::vector<CTxOut> vout;
CTxWitness wit; // Not const: can change without invalidating the txid cache
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) {
SerializeTransaction(*this, s, ser_action, nType, nVersion);
if (ser_action.ForRead()) {
UpdateHash();
}
}
bool IsNull() const {
return vin.empty() && vout.empty();
}
const uint256& GetHash() const {
return hash;
}
// Compute a hash that includes both transaction and witness data
uint256 GetWitnessHash() const;
// 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;
void UpdateHash() const;
};
/** A mutable version of CTransaction. */
struct CMutableTransaction
{
int32_t nVersion;
std::vector<CTxIn> vin;
std::vector<CTxOut> vout;
CTxWitness wit;
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) {
SerializeTransaction(*this, s, ser_action, nType, nVersion);
}
/** 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;
};
/** Compute the cost of a transaction, as defined by BIP 141 */
int64_t GetTransactionCost(const CTransaction &tx);
#endif // BITCOIN_PRIMITIVES_TRANSACTION_H