Bugfix: only track UTXO modification after lookup

Otherwise, if CCoinsViewCache::ModifyCoins throws an exception in between
setting hasModifier and constructing the CCoinsModifier, the cache ends up
in an inconsistent state, resulting in an assert failure in the next
modification.

Bug discovered by Wladimir J. van der Laan.
This commit is contained in:
Pieter Wuille 2015-01-04 17:15:02 +01:00
parent a99ef7d353
commit 02bced1661

View File

@ -106,7 +106,6 @@ bool CCoinsViewCache::GetCoins(const uint256 &txid, CCoins &coins) const {
CCoinsModifier CCoinsViewCache::ModifyCoins(const uint256 &txid) {
assert(!hasModifier);
hasModifier = true;
std::pair<CCoinsMap::iterator, bool> ret = cacheCoins.insert(std::make_pair(txid, CCoinsCacheEntry()));
if (ret.second) {
if (!base->GetCoins(txid, ret.first->second.coins)) {
@ -247,7 +246,10 @@ double CCoinsViewCache::GetPriority(const CTransaction &tx, int nHeight) const
return tx.ComputePriority(dResult);
}
CCoinsModifier::CCoinsModifier(CCoinsViewCache& cache_, CCoinsMap::iterator it_) : cache(cache_), it(it_) {}
CCoinsModifier::CCoinsModifier(CCoinsViewCache& cache_, CCoinsMap::iterator it_) : cache(cache_), it(it_) {
assert(!cache.hasModifier);
cache.hasModifier = true;
}
CCoinsModifier::~CCoinsModifier()
{