Add CTxUndo: transaction undo information

The CTxUndo class encapsulates data necessary to undo the effects of
a transaction on the txout set, namely the previous outputs consumed
by it (script + amount), and potentially transaction meta-data when
it is spent entirely.
This commit is contained in:
Pieter Wuille 2012-06-18 16:55:29 +02:00
parent 10fd8604d7
commit 44ac1c0fe3

View File

@ -673,6 +673,60 @@ public:
});)
};
/** Undo information for a CTxIn
*
* Contains the prevout's CTxOut being spent, and if this was the
* last output of the affected transaction, its metadata as well
* (coinbase or not, height, transaction version)
*/
class CTxInUndo
{
public:
CTxOut txout; // the txout data before being spent
bool fCoinBase; // if the outpoint was the last unspent: whether it belonged to a coinbase
unsigned int nHeight; // if the outpoint was the last unspent: its height
int nVersion; // if the outpoint was the last unspent: its version
CTxInUndo() : txout(), fCoinBase(false), nHeight(0), nVersion(0) {}
CTxInUndo(const CTxOut &txoutIn, bool fCoinBaseIn = false, unsigned int nHeightIn = 0, int nVersionIn = 0) : txout(txoutIn), fCoinBase(fCoinBaseIn), nHeight(nHeightIn), nVersion(nVersionIn) { }
unsigned int GetSerializeSize(int nType, int nVersion) const {
return ::GetSerializeSize(VARINT(nHeight*2+(fCoinBase ? 1 : 0)), nType, nVersion) +
(nHeight > 0 ? ::GetSerializeSize(VARINT(this->nVersion), nType, nVersion) : 0) +
::GetSerializeSize(CTxOutCompressor(REF(txout)), nType, nVersion);
}
template<typename Stream>
void Serialize(Stream &s, int nType, int nVersion) const {
::Serialize(s, VARINT(nHeight*2+(fCoinBase ? 1 : 0)), nType, nVersion);
if (nHeight > 0)
::Serialize(s, VARINT(this->nVersion), nType, nVersion);
::Serialize(s, CTxOutCompressor(REF(txout)), nType, nVersion);
}
template<typename Stream>
void Unserialize(Stream &s, int nType, int nVersion) {
unsigned int nCode = 0;
::Unserialize(s, VARINT(nCode), nType, nVersion);
nHeight = nCode / 2;
fCoinBase = nCode & 1;
if (nHeight > 0)
::Unserialize(s, VARINT(this->nVersion), nType, nVersion);
::Unserialize(s, REF(CTxOutCompressor(REF(txout))), nType, nVersion);
}
};
/** Undo information for a CTransaction */
class CTxUndo
{
public:
std::vector<CTxInUndo> vprevout;
IMPLEMENT_SERIALIZE(
READWRITE(vprevout);
)
};
/** pruned version of CTransaction: only retains metadata and unspent transaction outputs
*
* Serialized format:
@ -874,21 +928,28 @@ public:
Cleanup();
}
// mark an outpoint spent
bool Spend(const COutPoint &out) {
// mark an outpoint spent, and construct undo information
bool 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;
}
// mark a vout spent
bool Spend(int nPos) {
CTxInUndo undo;
COutPoint out(0, nPos);
return Spend(out);
return Spend(out, undo);
}
// check whether a particular output is still available