From adc66e70a7423be412f2ccda0c4fc69af681f284 Mon Sep 17 00:00:00 2001 From: MarcoFalke Date: Fri, 10 Nov 2017 14:22:36 -0500 Subject: [PATCH] Merge #11353: Small refactor of CCoinsViewCache::BatchWrite() 5b9748f97 Small refactor of CCoinsViewCache::BatchWrite() (Dan Raviv) Pull request description: `std::unordered_map::erase( const_iterator pos )` returns an iterator to the element following the removed one. Use that to optimize (probably minor-performance-wise, and definitely code-structure-wise) the implementation of `CCoinsViewCache::BatchWrite()`. Tree-SHA512: 00abc838ad91771cfcddd45688841c9414869b75289d09b483a7f0ba835614fe189e9c8aca8a80e3de78ee397ec14083ae52e2e92b7863b3b6eb0d0cb892c9dd --- src/coins.cpp | 94 ++++++++++++++++++++++++++------------------------- 1 file changed, 48 insertions(+), 46 deletions(-) diff --git a/src/coins.cpp b/src/coins.cpp index 4023cdeb95e3bc..c7365b2774b83d 100644 --- a/src/coins.cpp +++ b/src/coins.cpp @@ -146,56 +146,58 @@ void CCoinsViewCache::SetBestBlock(const uint256 &hashBlockIn) { } bool CCoinsViewCache::BatchWrite(CCoinsMap &mapCoins, const uint256 &hashBlockIn) { - for (CCoinsMap::iterator it = mapCoins.begin(); it != mapCoins.end();) { - if (it->second.flags & CCoinsCacheEntry::DIRTY) { // Ignore non-dirty entries (optimization). - CCoinsMap::iterator itUs = cacheCoins.find(it->first); - if (itUs == cacheCoins.end()) { - // The parent cache does not have an entry, while the child does - // We can ignore it if it's both FRESH and pruned in the child - if (!(it->second.flags & CCoinsCacheEntry::FRESH && it->second.coin.IsSpent())) { - // Otherwise we will need to create it in the parent - // and move the data up and mark it as dirty - CCoinsCacheEntry& entry = cacheCoins[it->first]; - entry.coin = std::move(it->second.coin); - cachedCoinsUsage += entry.coin.DynamicMemoryUsage(); - entry.flags = CCoinsCacheEntry::DIRTY; - // We can mark it FRESH in the parent if it was FRESH in the child - // Otherwise it might have just been flushed from the parent's cache - // and already exist in the grandparent - if (it->second.flags & CCoinsCacheEntry::FRESH) - entry.flags |= CCoinsCacheEntry::FRESH; + for (CCoinsMap::iterator it = mapCoins.begin(); it != mapCoins.end(); it = mapCoins.erase(it)) { + // Ignore non-dirty entries (optimization). + if (!(it->second.flags & CCoinsCacheEntry::DIRTY)) { + continue; + } + CCoinsMap::iterator itUs = cacheCoins.find(it->first); + if (itUs == cacheCoins.end()) { + // The parent cache does not have an entry, while the child does + // We can ignore it if it's both FRESH and pruned in the child + if (!(it->second.flags & CCoinsCacheEntry::FRESH && it->second.coin.IsSpent())) { + // Otherwise we will need to create it in the parent + // and move the data up and mark it as dirty + CCoinsCacheEntry& entry = cacheCoins[it->first]; + entry.coin = std::move(it->second.coin); + cachedCoinsUsage += entry.coin.DynamicMemoryUsage(); + entry.flags = CCoinsCacheEntry::DIRTY; + // We can mark it FRESH in the parent if it was FRESH in the child + // Otherwise it might have just been flushed from the parent's cache + // and already exist in the grandparent + if (it->second.flags & CCoinsCacheEntry::FRESH) { + entry.flags |= CCoinsCacheEntry::FRESH; } - } else { - // Assert that the child cache entry was not marked FRESH if the - // parent cache entry has unspent outputs. If this ever happens, - // it means the FRESH flag was misapplied and there is a logic - // error in the calling code. - if ((it->second.flags & CCoinsCacheEntry::FRESH) && !itUs->second.coin.IsSpent()) - throw std::logic_error("FRESH flag misapplied to cache entry for base transaction with spendable outputs"); + } + } else { + // Assert that the child cache entry was not marked FRESH if the + // parent cache entry has unspent outputs. If this ever happens, + // it means the FRESH flag was misapplied and there is a logic + // error in the calling code. + if ((it->second.flags & CCoinsCacheEntry::FRESH) && !itUs->second.coin.IsSpent()) { + throw std::logic_error("FRESH flag misapplied to cache entry for base transaction with spendable outputs"); + } - // Found the entry in the parent cache - if ((itUs->second.flags & CCoinsCacheEntry::FRESH) && it->second.coin.IsSpent()) { - // The grandparent does not have an entry, and the child is - // modified and being pruned. This means we can just delete - // it from the parent. - cachedCoinsUsage -= itUs->second.coin.DynamicMemoryUsage(); - cacheCoins.erase(itUs); - } else { - // A normal modification. - cachedCoinsUsage -= itUs->second.coin.DynamicMemoryUsage(); - itUs->second.coin = std::move(it->second.coin); - cachedCoinsUsage += itUs->second.coin.DynamicMemoryUsage(); - itUs->second.flags |= CCoinsCacheEntry::DIRTY; - // NOTE: It is possible the child has a FRESH flag here in - // the event the entry we found in the parent is pruned. But - // we must not copy that FRESH flag to the parent as that - // pruned state likely still needs to be communicated to the - // grandparent. - } + // Found the entry in the parent cache + if ((itUs->second.flags & CCoinsCacheEntry::FRESH) && it->second.coin.IsSpent()) { + // The grandparent does not have an entry, and the child is + // modified and being pruned. This means we can just delete + // it from the parent. + cachedCoinsUsage -= itUs->second.coin.DynamicMemoryUsage(); + cacheCoins.erase(itUs); + } else { + // A normal modification. + cachedCoinsUsage -= itUs->second.coin.DynamicMemoryUsage(); + itUs->second.coin = std::move(it->second.coin); + cachedCoinsUsage += itUs->second.coin.DynamicMemoryUsage(); + itUs->second.flags |= CCoinsCacheEntry::DIRTY; + // NOTE: It is possible the child has a FRESH flag here in + // the event the entry we found in the parent is pruned. But + // we must not copy that FRESH flag to the parent as that + // pruned state likely still needs to be communicated to the + // grandparent. } } - CCoinsMap::iterator itOld = it++; - mapCoins.erase(itOld); } hashBlock = hashBlockIn; return true;