1berry/qtbase
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

QCache: when overwriting, store the new cost instead of the delta

Browse Source 
The delta was clearly intended to be used on the total (and still is)
but it also wound up getting stored in the cache, which wouldn't be a
big problem unless the object was removed, in which case we could
incidentally 'free up more space' than intended.

Change-Id: Ib2b0f072d30da6d16a93dce60e4c5f6080c109fc
Reviewed-by: Lars Knoll <lars.knoll@qt.io>
(cherry picked from commit d2e2d0d3a6249ccbc17ec92acb32fec9a0d71807)
Reviewed-by: Qt Cherry-pick Bot <cherrypick_bot@qt-project.org>
This commit is contained in:
Mårten Nordheim 2021-01-12 17:25:03 +01:00 committed by Qt Cherry-pick Bot
parent 9e4d9fca8a
commit baa0356849
2 changed files with 16 additions and 1 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

3
src/corelib/tools/qcache.h
View File

@ -245,8 +245,9 @@ public:
auto result = d.findOrInsert(key);
Node *n = result.it.node();
if (result.initialized) {
cost -= n->value.cost;
auto prevCost = n->value.cost;
result.it.node()->emplace(object, cost);
cost -= prevCost;
relink(key);
} else {
Node::createInPlace(n, key, object, cost);

14
tests/auto/corelib/tools/qcache/tst_qcache.cpp
View File

@ -49,6 +49,7 @@ private slots:
void axioms_on_key_type();
void largeCache();
void internalChainOrderAfterEntryUpdate();
void emplaceLowerCost();
};
@ -431,5 +432,18 @@ void tst_QCache::internalChainOrderAfterEntryUpdate()
QCOMPARE(cache.size(), 0);
}
void tst_QCache::emplaceLowerCost()
{
QCache<QString, int> cache;
cache.setMaxCost(5);
cache.insert("a", new int, 3); // insert high cost
cache.insert("a", new int, 1); // and then exchange it with a lower-cost object
QCOMPARE(cache.totalCost(), 1);
cache.remove("a"); // then remove the object
// The cache should now have a cost == 0 and be empty.
QCOMPARE(cache.totalCost(), 0);
QVERIFY(cache.isEmpty());
}
QTEST_APPLESS_MAIN(tst_QCache)
#include "tst_qcache.moc"