highperfocused/bitcoin
1
0
Fork 0
mirror of https://github.com/bitcoin/bitcoin.git synced 2026-01-19 14:53:43 +01:00
Code Issues Packages Projects Releases Wiki Activity

[doc] MemPoolAccept coins views

Browse Source
This commit is contained in:
glozow
2025-07-14 12:38:12 -04:00
parent ba02c30b8a
commit 98ba2b1db2
1 changed files with 21 additions and 1 deletions
Download Patch File Download Diff File Expand all files Collapse all files

22
src/validation.cpp
View File

@@ -725,8 +725,27 @@ private:
private:
CTxMemPool& m_pool;
/** Holds a cached view of available coins from the UTXO set, mempool, and artificial temporary coins (to enable package validation).
* The view doesn't track whether a coin previously existed but has now been spent. We detect conflicts in other ways:
* - conflicts within a transaction are checked in CheckTransaction (bad-txns-inputs-duplicate)
* - conflicts within a package are checked in IsWellFormedPackage (conflict-in-package)
* - conflicts with an existing mempool transaction are found in CTxMemPool::GetConflictTx and replacements are allowed
* The temporary coins should persist between individual transaction checks so that package validation is possible,
* but must be cleaned up when we finish validating a subpackage, whether accepted or rejected. The cache must also
* be cleared when mempool contents change (when a changeset is applied or when the mempool trims itself) because it
* can return cached coins that no longer exist in the backend. Use CleanupTemporaryCoins() anytime you are finished
* with a SubPackageState or call LimitMempoolSize().
*/
CCoinsViewCache m_view;
// These are the two possible backends for m_view.
/** When m_view is connected to m_viewmempool as its backend, it can pull coins from the mempool and from the UTXO
* set. This is also where temporary coins are stored. */
CCoinsViewMemPool m_viewmempool;
/** When m_view is connected to m_dummy, it can no longer look up coins from the mempool or UTXO set (meaning no disk
* operations happen), but can still return coins it accessed previously. Useful for keeping track of which coins
* were pulled from disk. */
CCoinsView m_dummy;
Chainstate& m_active_chainstate;
@@ -1651,7 +1670,8 @@ void MemPoolAccept::CleanupTemporaryCoins()
// (3) Confirmed coins don't need to be removed. The chainstate has not changed (we are
// holding cs_main and no blocks have been processed) so the confirmed tx cannot disappear like
// a mempool tx can. The coin may now be spent after we submitted a tx to mempool, but
// we have already checked that the package does not have 2 transactions spending the same coin.
// we have already checked that the package does not have 2 transactions spending the same coin
// and we check whether a mempool transaction spends conflicting coins (CTxMemPool::GetConflictTx).
// Keeping them in m_view is an optimization to not re-fetch confirmed coins if we later look up
// inputs for this transaction again.
for (const auto& outpoint : m_viewmempool.GetNonBaseCoins()) {