diff options
author | Dario Freddi <dario.freddi@ispirata.com> | 2013-08-07 11:17:25 +0200 |
---|---|---|
committer | The Qt Project <gerrit-noreply@qt-project.org> | 2013-08-07 12:42:45 +0200 |
commit | 5885b8f775998c30d53f40b7f368c5f6364e6df4 (patch) | |
tree | 7921f5dc1d9dfde2fd45cfe53ca2dcde46ed7e7a | |
parent | 4881f9db7cf338f8dc5233591bd5c11ecd2f8ca9 (diff) |
qobject: Do not destroy slot objects inside a lock
This prevents deadlocks in case the destructor re-enters.
(Example: a functor containing a QSharedPointer of a QObject)
This also fixes a leaked slot object in disconnectHelper.
Change-Id: Ia939790e3b54e64067b99540974306b4808a77f2
Reviewed-by: Olivier Goffart <ogoffart@woboq.com>
-rw-r--r-- | src/corelib/kernel/qobject.cpp | 34 | ||||
-rw-r--r-- | tests/auto/corelib/kernel/qobject/tst_qobject.cpp | 58 |
2 files changed, 77 insertions, 15 deletions
diff --git a/src/corelib/kernel/qobject.cpp b/src/corelib/kernel/qobject.cpp index 02794e9fe3..33e2adf5ba 100644 --- a/src/corelib/kernel/qobject.cpp +++ b/src/corelib/kernel/qobject.cpp @@ -816,6 +816,14 @@ QObject::~QObject() m->unlock(); connectionList.first = c->nextConnectionList; + + // The destroy operation must happen outside the lock + if (c->isSlotObject) { + locker.unlock(); + c->slotObj->destroyIfLastRef(); + c->isSlotObject = false; + locker.relock(); + } c->deref(); } } @@ -3135,6 +3143,13 @@ bool QMetaObjectPrivate::disconnectHelper(QObjectPrivate::Connection *c, c->receiver = 0; + if (c->isSlotObject) { + senderMutex->unlock(); + c->slotObj->destroyIfLastRef(); + c->isSlotObject = false; + senderMutex->lock(); + } + success = true; if (disconnectType == DisconnectOne) @@ -4363,16 +4378,19 @@ bool QObject::disconnect(const QMetaObject::Connection &connection) QMutex *senderMutex = signalSlotLock(c->sender); QMutex *receiverMutex = signalSlotLock(c->receiver); - QOrderedMutexLocker locker(senderMutex, receiverMutex); - QObjectConnectionListVector *connectionLists = QObjectPrivate::get(c->sender)->connectionLists; - Q_ASSERT(connectionLists); - connectionLists->dirty = true; + { + QOrderedMutexLocker locker(senderMutex, receiverMutex); - *c->prev = c->next; - if (c->next) - c->next->prev = c->prev; - c->receiver = 0; + QObjectConnectionListVector *connectionLists = QObjectPrivate::get(c->sender)->connectionLists; + Q_ASSERT(connectionLists); + connectionLists->dirty = true; + + *c->prev = c->next; + if (c->next) + c->next->prev = c->prev; + c->receiver = 0; + } // destroy the QSlotObject, if possible if (c->isSlotObject) { diff --git a/tests/auto/corelib/kernel/qobject/tst_qobject.cpp b/tests/auto/corelib/kernel/qobject/tst_qobject.cpp index d16369de02..1cdf39018b 100644 --- a/tests/auto/corelib/kernel/qobject/tst_qobject.cpp +++ b/tests/auto/corelib/kernel/qobject/tst_qobject.cpp @@ -5726,27 +5726,44 @@ void tst_QObject::connectFunctorOverloads() #endif } +class GetSenderObject : public QObject +{ + Q_OBJECT +public: + QObject *accessSender() { return sender(); } + +public Q_SLOTS: + void triggerSignal() { Q_EMIT aSignal(); } + +Q_SIGNALS: + void aSignal(); +}; + static int countedStructObjectsCount = 0; struct CountedStruct { - CountedStruct() { ++countedStructObjectsCount; } - CountedStruct(const CountedStruct &) { ++countedStructObjectsCount; } + CountedStruct() : sender(Q_NULLPTR) { ++countedStructObjectsCount; } + CountedStruct(GetSenderObject *sender) : sender(sender) { ++countedStructObjectsCount; } + CountedStruct(const CountedStruct &o) : sender(o.sender) { ++countedStructObjectsCount; } CountedStruct &operator=(const CountedStruct &) { return *this; } - ~CountedStruct() { --countedStructObjectsCount; } - void operator()() const {} + // accessSender here allows us to check if there's a deadlock + ~CountedStruct() { --countedStructObjectsCount; if (sender != Q_NULLPTR) (void)sender->accessSender(); } + void operator()() const { } + + GetSenderObject *sender; }; void tst_QObject::disconnectDoesNotLeakFunctor() { QCOMPARE(countedStructObjectsCount, 0); { + GetSenderObject obj; QMetaObject::Connection c; { - CountedStruct s; + CountedStruct s(&obj); QCOMPARE(countedStructObjectsCount, 1); - QTimer timer; - c = connect(&timer, &QTimer::timeout, s); + c = connect(&obj, &GetSenderObject::aSignal, s); QVERIFY(c); QCOMPARE(countedStructObjectsCount, 2); QVERIFY(QObject::disconnect(c)); @@ -5797,6 +5814,33 @@ void tst_QObject::disconnectDoesNotLeakFunctor() } QCOMPARE(countedStructObjectsCount, 0); { + QTimer *timer = new QTimer; + QEventLoop e; + + connect(timer, &QTimer::timeout, CountedStruct()); + QCOMPARE(countedStructObjectsCount, 1); // only one instance, in Qt internals + timer->deleteLater(); + connect(timer, &QObject::destroyed, &e, &QEventLoop::quit, Qt::QueuedConnection); + e.exec(); + QCOMPARE(countedStructObjectsCount, 0); // functor being destroyed + } + QCOMPARE(countedStructObjectsCount, 0); + { + GetSenderObject obj; + + connect(&obj, &GetSenderObject::aSignal, CountedStruct(&obj)); + QCOMPARE(countedStructObjectsCount, 1); + } + QCOMPARE(countedStructObjectsCount, 0); + { + GetSenderObject obj; + + connect(&obj, &GetSenderObject::aSignal, CountedStruct(&obj)); + QCOMPARE(countedStructObjectsCount, 1); + QObject::disconnect(&obj, &GetSenderObject::aSignal, 0, 0); + } + QCOMPARE(countedStructObjectsCount, 0); + { #if defined(Q_COMPILER_LAMBDA) CountedStruct s; QCOMPARE(countedStructObjectsCount, 1); |