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

Protect all accesses to the global engine cache by a mutex

Browse Source 
Otherwise, we'll end up with corrupted memory when using
QRegExp from multiple threads.

Amends bbdc1b5ccbb19405f997cd67ec53b2c4860105f7.

Change-Id: I9d35897629d0bc26503aa0c537c5f99013921fdd
Reviewed-by: Simon Hausmann <simon.hausmann@qt.io>
This commit is contained in:
Lars Knoll 2018-04-23 21:08:10 +02:00 committed by Simon Hausmann
parent 960424f86b
commit a9fc91466c
1 changed files with 32 additions and 34 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

58
src/corelib/tools/qregexp.cpp
View File

@ -3813,60 +3813,57 @@ struct QRegExpPrivate
};
#if !defined(QT_NO_REGEXP_OPTIM)
struct QRECache
{
typedef QHash<QRegExpEngineKey, QRegExpEngine *> EngineCache;
Q_GLOBAL_STATIC(EngineCache, globalEngineCache)
typedef QCache<QRegExpEngineKey, QRegExpEngine> UnusedEngineCache;
Q_GLOBAL_STATIC(UnusedEngineCache, globalUnusedEngineCache)
static QBasicMutex globalEngineCacheMutex;
EngineCache usedEngines;
UnusedEngineCache unusedEngines;
};
Q_GLOBAL_STATIC(QRECache, engineCache)
static QBasicMutex engineCacheMutex;
#endif // QT_NO_REGEXP_OPTIM
static void derefEngine(QRegExpEngine *eng, const QRegExpEngineKey &key)
{
if (!eng->ref.deref()) {
#if !defined(QT_NO_REGEXP_OPTIM)
if (globalUnusedEngineCache()) {
QMutexLocker locker(&globalEngineCacheMutex);
QT_TRY {
globalUnusedEngineCache()->insert(key, eng, 4 + key.pattern.length() / 4);
} QT_CATCH(const std::bad_alloc &) {
// in case of an exception (e.g. oom), just delete the engine
delete eng;
}
if (globalEngineCache())
globalEngineCache()->remove(key);
QMutexLocker locker(&engineCacheMutex);
if (!eng->ref.deref()) {
if (QRECache *c = engineCache()) {
c->unusedEngines.insert(key, eng, 4 + key.pattern.length() / 4);
c->usedEngines.remove(key);
} else {
delete eng;
}
}
#else
Q_UNUSED(key);
if (!eng->ref.deref())
delete eng;
#endif
}
}
static void prepareEngine_helper(QRegExpPrivate *priv)
{
bool initMatchState = !priv->eng;
Q_ASSERT(!priv->eng);
#if !defined(QT_NO_REGEXP_OPTIM)
if (!priv->eng && globalUnusedEngineCache()) {
QMutexLocker locker(&globalEngineCacheMutex);
priv->eng = globalUnusedEngineCache()->take(priv->engineKey);
if (!priv->eng && globalEngineCache())
priv->eng = globalEngineCache()->value(priv->engineKey);
if (priv->eng != 0)
QMutexLocker locker(&engineCacheMutex);
if (QRECache *c = engineCache()) {
priv->eng = c->unusedEngines.take(priv->engineKey);
if (!priv->eng)
priv->eng = c->usedEngines.value(priv->engineKey);
if (!priv->eng)
priv->eng = new QRegExpEngine(priv->engineKey);
else
priv->eng->ref.ref();
c->usedEngines.insert(priv->engineKey, priv->eng);
return;
}
#endif // QT_NO_REGEXP_OPTIM
if (!priv->eng)
priv->eng = new QRegExpEngine(priv->engineKey);
#if !defined(QT_NO_REGEXP_OPTIM)
if (globalEngineCache())
globalEngineCache()->insert(priv->engineKey, priv->eng);
#endif
if (initMatchState)
priv->matchState.prepareForMatch(priv->eng);
}
inline static void prepareEngine(QRegExpPrivate *priv)
@ -3874,6 +3871,7 @@ inline static void prepareEngine(QRegExpPrivate *priv)
if (priv->eng)
return;
prepareEngine_helper(priv);
priv->matchState.prepareForMatch(priv->eng);
}
static void prepareEngineForMatch(QRegExpPrivate *priv, const QString &str)