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Store/allow tx metadata in all undo records

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Previously, transaction metadata (height, coinbase or not, and before
the previous commit also nVersion) was only stored for undo records
that correspond to the last output of a transaction being spent.

This only saves 2 bytes per undo record. Change this to storing this
information for every undo record, and stop complaining for having it
in non-last output spends. This means that undo dat written with
this patch won't be readable by older versions anymore.
This commit is contained in:
Pieter Wuille 2017-04-25 11:29:19 -07:00
parent c3aa0c1194
commit 7d991b55db
2 changed files with 11 additions and 9 deletions
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3
src/undo.h
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@ -12,8 +12,7 @@
/** 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
* Contains the prevout's CTxOut being spent, and its metadata as well
* (coinbase or not, height). Earlier versions also stored the transaction
* version.
*/

17
src/validation.cpp
View file

@ -1082,11 +1082,9 @@ void UpdateCoins(const CTransaction& tx, CCoinsViewCache& inputs, CTxUndo &txund
// mark an outpoint spent, and construct undo information
txundo.vprevout.push_back(CTxInUndo(coins->vout[nPos]));
coins->Spend(nPos);
if (coins->vout.size() == 0) {
CTxInUndo& undo = txundo.vprevout.back();
undo.nHeight = coins->nHeight;
undo.fCoinBase = coins->fCoinBase;
}
CTxInUndo& undo = txundo.vprevout.back();
undo.nHeight = coins->nHeight;
undo.fCoinBase = coins->fCoinBase;
}
}
// add outputs
@ -1266,11 +1264,16 @@ int ApplyTxInUndo(const CTxInUndo& undo, CCoinsViewCache& view, const COutPoint&
CCoinsModifier coins = view.ModifyCoins(out.hash);
if (undo.nHeight != 0) {
// undo data contains height: this is the last output of the prevout tx being spent
if (!coins->IsPruned()) fClean = false; // overwriting existing transaction
if (!coins->IsPruned()) {
if (coins->fCoinBase != undo.fCoinBase || (uint32_t)coins->nHeight != undo.nHeight) fClean = false; // metadata mismatch
}
// restore height/coinbase tx metadata from undo data
coins->fCoinBase = undo.fCoinBase;
coins->nHeight = undo.nHeight;
} else {
// Undo data does not contain height/coinbase. This should never happen
// for newly created undo entries. Previously, this data was only saved
// for the last spend of a transaction's outputs, so check IsPruned().
if (coins->IsPruned()) fClean = false; // adding output to missing transaction
}
if (coins->IsAvailable(out.n)) fClean = false; // overwriting existing output