diff options
author | Thiago Macieira <thiago.macieira@nokia.com> | 2011-06-23 14:11:50 +0200 |
---|---|---|
committer | Qt by Nokia <qt-info@nokia.com> | 2011-07-11 12:43:52 +0200 |
commit | f9035587b98ac5dc9491e642b8ec84470ec03f0e (patch) | |
tree | f91962125963ee91ff6d13fa029606966b00a272 /src | |
parent | 915ec02cadcd6e3ca423968a094a97ad417783a1 (diff) |
Replace try/catch blocks in favour of destructors in the event loop.
This has two direct benefits:
1) compiles regardless of -fno-exceptions: no need for #ifndef
QT_NO_EXCEPTIONS or QT_TRY/QT_CATCH
2) no QT_RETHROW either, which means the backtrace of an application
crashing due to an uncaught exception will include the actual throw
point.
Change-Id: I18e5500e121bfa81431ef16699df96d962794f0e
Reviewed-on: http://codereview.qt.nokia.com/663
Reviewed-by: Qt Sanity Bot <qt_sanity_bot@ovi.com>
Reviewed-by: Olivier Goffart <olivier.goffart@nokia.com>
Diffstat (limited to 'src')
-rw-r--r-- | src/corelib/kernel/qcoreapplication.cpp | 101 | ||||
-rw-r--r-- | src/corelib/kernel/qeventloop.cpp | 66 | ||||
-rw-r--r-- | src/corelib/kernel/qobject.cpp | 130 |
3 files changed, 156 insertions, 141 deletions
diff --git a/src/corelib/kernel/qcoreapplication.cpp b/src/corelib/kernel/qcoreapplication.cpp index 5f11b10ec5..2458f9649e 100644 --- a/src/corelib/kernel/qcoreapplication.cpp +++ b/src/corelib/kernel/qcoreapplication.cpp @@ -816,7 +816,16 @@ bool QCoreApplication::notifyInternal(QObject *receiver, QEvent *event) // call overhead. QObjectPrivate *d = receiver->d_func(); QThreadData *threadData = d->threadData; - ++threadData->loopLevel; + + // Exception-safety without try/catch + struct Incrementer { + int &variable; + inline Incrementer(int &variable) : variable(variable) + { ++variable; } + inline ~Incrementer() + { --variable; } + }; + Incrementer inc(threadData->loopLevel); #ifdef QT_JAMBI_BUILD int deleteWatch = 0; @@ -827,12 +836,7 @@ bool QCoreApplication::notifyInternal(QObject *receiver, QEvent *event) #endif bool returnValue; - QT_TRY { - returnValue = notify(receiver, event); - } QT_CATCH (...) { - --threadData->loopLevel; - QT_RETHROW; - } + returnValue = notify(receiver, event); #ifdef QT_JAMBI_BUILD // Restore the previous state if the object was not deleted.. @@ -841,7 +845,6 @@ bool QCoreApplication::notifyInternal(QObject *receiver, QEvent *event) } QObjectPrivate::resetDeleteWatch(d, oldDeleteWatch, deleteWatch); #endif - --threadData->loopLevel; return returnValue; } @@ -1384,6 +1387,40 @@ void QCoreApplicationPrivate::sendPostedEvents(QObject *receiver, int event_type int &i = (!event_type && !receiver) ? data->postEventList.startOffset : startOffset; data->postEventList.insertionOffset = data->postEventList.size(); + // Exception-safe cleaning up without the need for a try/catch block + struct CleanUp { + QObject *receiver; + int event_type; + QThreadData *data; + bool exceptionCaught; + + inline CleanUp(QObject *receiver, int event_type, QThreadData *data) : + receiver(receiver), event_type(event_type), data(data), exceptionCaught(true) + {} + inline ~CleanUp() + { + if (exceptionCaught) { + // since we were interrupted, we need another pass to make sure we clean everything up + data->canWait = false; + } + + --data->postEventList.recursion; + if (!data->postEventList.recursion && !data->canWait && data->eventDispatcher) + data->eventDispatcher->wakeUp(); + + // clear the global list, i.e. remove everything that was + // delivered. + if (!event_type && !receiver && data->postEventList.startOffset >= 0) { + const QPostEventList::iterator it = data->postEventList.begin(); + data->postEventList.erase(it, it + data->postEventList.startOffset); + data->postEventList.insertionOffset -= data->postEventList.startOffset; + Q_ASSERT(data->postEventList.insertionOffset >= 0); + data->postEventList.startOffset = 0; + } + } + }; + CleanUp cleanup(receiver, event_type, data); + while (i < data->postEventList.size()) { // avoid live-lock if (i >= data->postEventList.insertionOffset) @@ -1422,7 +1459,7 @@ void QCoreApplicationPrivate::sendPostedEvents(QObject *receiver, int event_type // first, we diddle the event so that we can deliver // it, and that no one will try to touch it later. pe.event->posted = false; - QEvent * e = pe.event; + QScopedPointer<QEvent> e(pe.event); QObject * r = pe.receiver; --r->d_func()->postedEvents; @@ -1432,49 +1469,23 @@ void QCoreApplicationPrivate::sendPostedEvents(QObject *receiver, int event_type // for the next event. const_cast<QPostEvent &>(pe).event = 0; - locker.unlock(); - // after all that work, it's time to deliver the event. -#ifdef QT_NO_EXCEPTIONS - QCoreApplication::sendEvent(r, e); -#else - try { - QCoreApplication::sendEvent(r, e); - } catch (...) { - delete e; - locker.relock(); - - // since we were interrupted, we need another pass to make sure we clean everything up - data->canWait = false; - - // uglehack: copied from below - --data->postEventList.recursion; - if (!data->postEventList.recursion && !data->canWait && data->eventDispatcher) - data->eventDispatcher->wakeUp(); - throw; // rethrow - } -#endif + struct MutexUnlocker + { + QMutexLocker &m; + MutexUnlocker(QMutexLocker &m) : m(m) { m.unlock(); } + ~MutexUnlocker() { m.relock(); } + }; + MutexUnlocker unlocker(locker); - delete e; - locker.relock(); + // after all that work, it's time to deliver the event. + QCoreApplication::sendEvent(r, e.data()); // careful when adding anything below this point - the // sendEvent() call might invalidate any invariants this // function depends on. } - --data->postEventList.recursion; - if (!data->postEventList.recursion && !data->canWait && data->eventDispatcher) - data->eventDispatcher->wakeUp(); - - // clear the global list, i.e. remove everything that was - // delivered. - if (!event_type && !receiver && data->postEventList.startOffset >= 0) { - const QPostEventList::iterator it = data->postEventList.begin(); - data->postEventList.erase(it, it + data->postEventList.startOffset); - data->postEventList.insertionOffset -= data->postEventList.startOffset; - Q_ASSERT(data->postEventList.insertionOffset >= 0); - data->postEventList.startOffset = 0; - } + cleanup.exceptionCaught = false; } /*! diff --git a/src/corelib/kernel/qeventloop.cpp b/src/corelib/kernel/qeventloop.cpp index 5a4ce973bc..37c06a2093 100644 --- a/src/corelib/kernel/qeventloop.cpp +++ b/src/corelib/kernel/qeventloop.cpp @@ -184,49 +184,47 @@ int QEventLoop::exec(ProcessEventsFlags flags) qWarning("QEventLoop::exec: instance %p has already called exec()", this); return -1; } - d->inExec = true; - d->exit = false; - ++d->threadData->loopLevel; - d->threadData->eventLoops.push(this); - locker.unlock(); + + struct LoopReference { + QEventLoopPrivate *d; + QMutexLocker &locker; + + bool exceptionCaught; + LoopReference(QEventLoopPrivate *d, QMutexLocker &locker) : d(d), locker(locker), exceptionCaught(true) + { + d->inExec = true; + d->exit = false; + ++d->threadData->loopLevel; + d->threadData->eventLoops.push(d->q_func()); + locker.unlock(); + } + + ~LoopReference() + { + if (exceptionCaught) { + qWarning("Qt has caught an exception thrown from an event handler. Throwing\n" + "exceptions from an event handler is not supported in Qt. You must\n" + "reimplement QApplication::notify() and catch all exceptions there.\n"); + } + locker.relock(); + QEventLoop *eventLoop = d->threadData->eventLoops.pop(); + Q_ASSERT_X(eventLoop == d->q_func(), "QEventLoop::exec()", "internal error"); + Q_UNUSED(eventLoop); // --release warning + d->inExec = false; + --d->threadData->loopLevel; + } + }; + LoopReference ref(d, locker); // remove posted quit events when entering a new event loop QCoreApplication *app = QCoreApplication::instance(); if (app && app->thread() == thread()) QCoreApplication::removePostedEvents(app, QEvent::Quit); -#if defined(QT_NO_EXCEPTIONS) while (!d->exit) processEvents(flags | WaitForMoreEvents | EventLoopExec); -#else - try { - while (!d->exit) - processEvents(flags | WaitForMoreEvents | EventLoopExec); - } catch (...) { - qWarning("Qt has caught an exception thrown from an event handler. Throwing\n" - "exceptions from an event handler is not supported in Qt. You must\n" - "reimplement QApplication::notify() and catch all exceptions there.\n"); - - // copied from below - locker.relock(); - QEventLoop *eventLoop = d->threadData->eventLoops.pop(); - Q_ASSERT_X(eventLoop == this, "QEventLoop::exec()", "internal error"); - Q_UNUSED(eventLoop); // --release warning - d->inExec = false; - --d->threadData->loopLevel; - - throw; - } -#endif - - // copied above - locker.relock(); - QEventLoop *eventLoop = d->threadData->eventLoops.pop(); - Q_ASSERT_X(eventLoop == this, "QEventLoop::exec()", "internal error"); - Q_UNUSED(eventLoop); // --release warning - d->inExec = false; - --d->threadData->loopLevel; + ref.exceptionCaught = false; return d->returnCode; } diff --git a/src/corelib/kernel/qobject.cpp b/src/corelib/kernel/qobject.cpp index 192e0accaa..c1ac70d8da 100644 --- a/src/corelib/kernel/qobject.cpp +++ b/src/corelib/kernel/qobject.cpp @@ -125,6 +125,39 @@ extern "C" Q_CORE_EXPORT void qt_removeObject(QObject *) } } +struct QConnectionSenderSwitcher { + QObject *receiver; + QObjectPrivate::Sender *previousSender; + QObjectPrivate::Sender currentSender; + bool switched; + + inline QConnectionSenderSwitcher() : switched(false) {} + + inline QConnectionSenderSwitcher(QObject *receiver, QObject *sender, int signal_absolute_id) + { + switchSender(receiver, sender, signal_absolute_id); + } + + inline void switchSender(QObject *receiver, QObject *sender, int signal_absolute_id) + { + this->receiver = receiver; + currentSender.sender = sender; + currentSender.signal = signal_absolute_id; + currentSender.ref = 1; + previousSender = QObjectPrivate::setCurrentSender(receiver, ¤tSender); + switched = true; + } + + inline ~QConnectionSenderSwitcher() + { + if (switched) + QObjectPrivate::resetCurrentSender(receiver, ¤tSender, previousSender); + } +private: + Q_DISABLE_COPY(QConnectionSenderSwitcher) +}; + + void (*QAbstractDeclarativeData::destroyed)(QAbstractDeclarativeData *, QObject *) = 0; void (*QAbstractDeclarativeData::parentChanged)(QAbstractDeclarativeData *, QObject *, QObject *) = 0; void (*QAbstractDeclarativeData::objectNameChanged)(QAbstractDeclarativeData *, QObject *) = 0; @@ -1083,23 +1116,10 @@ bool QObject::event(QEvent *e) d_func()->inEventHandler = false; #endif QMetaCallEvent *mce = static_cast<QMetaCallEvent*>(e); - QObjectPrivate::Sender currentSender; - currentSender.sender = const_cast<QObject*>(mce->sender()); - currentSender.signal = mce->signalId(); - currentSender.ref = 1; - QObjectPrivate::Sender * const previousSender = - QObjectPrivate::setCurrentSender(this, ¤tSender); -#if defined(QT_NO_EXCEPTIONS) + + QConnectionSenderSwitcher sw(this, const_cast<QObject*>(mce->sender()), mce->signalId()); + mce->placeMetaCall(this); -#else - QT_TRY { - mce->placeMetaCall(this); - } QT_CATCH(...) { - QObjectPrivate::resetCurrentSender(this, ¤tSender, previousSender); - QT_RETHROW; - } -#endif - QObjectPrivate::resetCurrentSender(this, ¤tSender, previousSender); break; } @@ -2976,7 +2996,7 @@ bool QMetaObjectPrivate::connect(const QObject *sender, int signal_index, type &= Qt::UniqueConnection - 1; } - QObjectPrivate::Connection *c = new QObjectPrivate::Connection; + QScopedPointer<QObjectPrivate::Connection> c(new QObjectPrivate::Connection); c->sender = s; c->receiver = r; c->method_relative = method_index; @@ -2986,16 +3006,11 @@ bool QMetaObjectPrivate::connect(const QObject *sender, int signal_index, c->nextConnectionList = 0; c->callFunction = callFunction; - QT_TRY { - QObjectPrivate::get(s)->addConnection(signal_index, c); - } QT_CATCH(...) { - delete c; - QT_RETHROW; - } + QObjectPrivate::get(s)->addConnection(signal_index, c.data()); c->prev = &(QObjectPrivate::get(r)->senders); c->next = *c->prev; - *c->prev = c; + *c->prev = c.data(); if (c->next) c->next->prev = &c->next; @@ -3006,6 +3021,7 @@ bool QMetaObjectPrivate::connect(const QObject *sender, int signal_index, sender_d->connectedSignals[signal_index >> 5] |= (1 << (signal_index & 0x1f)); } + c.take(); // stop tracking return true; } @@ -3264,16 +3280,37 @@ void QMetaObject::activate(QObject *sender, const QMetaObject *m, int local_sign Qt::HANDLE currentThreadId = QThread::currentThreadId(); + { QMutexLocker locker(signalSlotLock(sender)); - QObjectConnectionListVector *connectionLists = sender->d_func()->connectionLists; - if (!connectionLists) { + struct ConnectionListsRef { + QObjectConnectionListVector *connectionLists; + ConnectionListsRef(QObjectConnectionListVector *connectionLists) : connectionLists(connectionLists) + { + if (connectionLists) + ++connectionLists->inUse; + } + ~ConnectionListsRef() + { + if (!connectionLists) + return; + + --connectionLists->inUse; + Q_ASSERT(connectionLists->inUse >= 0); + if (connectionLists->orphaned) { + if (!connectionLists->inUse) + delete connectionLists; + } + } + + QObjectConnectionListVector *operator->() const { return connectionLists; } + }; + ConnectionListsRef connectionLists = sender->d_func()->connectionLists; + if (!connectionLists.connectionLists) { locker.unlock(); if (qt_signal_spy_callback_set.signal_end_callback != 0) qt_signal_spy_callback_set.signal_end_callback(sender, signal_absolute_index); return; } - ++connectionLists->inUse; - const QObjectPrivate::ConnectionList *list; if (signal_index < connectionLists->count()) @@ -3323,13 +3360,10 @@ void QMetaObject::activate(QObject *sender, const QMetaObject *m, int local_sign #endif } - QObjectPrivate::Sender currentSender; - QObjectPrivate::Sender *previousSender = 0; + QConnectionSenderSwitcher sw; + if (receiverInSameThread) { - currentSender.sender = sender; - currentSender.signal = signal_absolute_index; - currentSender.ref = 1; - previousSender = QObjectPrivate::setCurrentSender(receiver, ¤tSender); + sw.switchSender(receiver, sender, signal_absolute_index); } const QObjectPrivate::StaticMetaCallFunction callFunction = c->callFunction; const int method_relative = c->method_relative; @@ -3354,23 +3388,7 @@ void QMetaObject::activate(QObject *sender, const QMetaObject *m, int local_sign argv ? argv : empty_argv); } -#if defined(QT_NO_EXCEPTIONS) metacall(receiver, QMetaObject::InvokeMetaMethod, method, argv ? argv : empty_argv); -#else - QT_TRY { - metacall(receiver, QMetaObject::InvokeMetaMethod, method, argv ? argv : empty_argv); - } QT_CATCH(...) { - locker.relock(); - if (receiverInSameThread) - QObjectPrivate::resetCurrentSender(receiver, ¤tSender, previousSender); - - --connectionLists->inUse; - Q_ASSERT(connectionLists->inUse >= 0); - if (connectionLists->orphaned && !connectionLists->inUse) - delete connectionLists; - QT_RETHROW; - } -#endif if (qt_signal_spy_callback_set.slot_end_callback != 0) qt_signal_spy_callback_set.slot_end_callback(receiver, method); @@ -3378,9 +3396,6 @@ void QMetaObject::activate(QObject *sender, const QMetaObject *m, int local_sign locker.relock(); } - if (receiverInSameThread) - QObjectPrivate::resetCurrentSender(receiver, ¤tSender, previousSender); - if (connectionLists->orphaned) break; } while (c != last && (c = c->nextConnectionList) != 0); @@ -3391,17 +3406,8 @@ void QMetaObject::activate(QObject *sender, const QMetaObject *m, int local_sign //start over for all signals; ((list = &connectionLists->allsignals), true)); - --connectionLists->inUse; - Q_ASSERT(connectionLists->inUse >= 0); - if (connectionLists->orphaned) { - if (!connectionLists->inUse) - delete connectionLists; - } else if (connectionLists->dirty) { - sender->d_func()->cleanConnectionLists(); } - locker.unlock(); - if (qt_signal_spy_callback_set.signal_end_callback != 0) qt_signal_spy_callback_set.signal_end_callback(sender, signal_absolute_index); |