Speedup destruction of QObject if the eventloop is not entered.

QObjectPrivate::removePendingChildInsertedEvents intoduce O(n^2) complexity.
Remove this function and instead check the object has not been removed/reparented

Known side effects: if the object would be parented multiple times to the
same object, multiple QEvent::ChildInserted will be sends

This would also create the QWeakPointer external refcount for almost each objects.

Task-number: QTBUG-6546
Reviewed-by: Brad

4 files changed, 5 insertions, 35 deletions

diff --git a/src/corelib/kernel/qcoreapplication.cpp b/src/corelib/kernel/qcoreapplication.cpp
index 4e6e6b9..a354498 100644
--- a/src/corelib/kernel/qcoreapplication.cpp
+++ b/src/corelib/kernel/qcoreapplication.cpp
@@ -805,11 +805,6 @@ bool QCoreApplication::notify(QObject *receiver, QEvent *event)
     d->checkReceiverThread(receiver);
 #endif
 
-#ifdef QT3_SUPPORT
-    if (event->type() == QEvent::ChildRemoved && !receiver->d_func()->pendingChildInsertedEvents.isEmpty())
-        receiver->d_func()->removePendingChildInsertedEvents(static_cast<QChildEvent *>(event)->child());
-#endif // QT3_SUPPORT
-
     return receiver->isWidgetType() ? false : d->notify_helper(receiver, event);
 }
 
@@ -1475,7 +1470,7 @@ void QCoreApplication::removePostedEvents(QObject *receiver, int eventType)
             --pe.receiver->d_func()->postedEvents;
 #ifdef QT3_SUPPORT
             if (pe.event->type() == QEvent::ChildInsertedRequest)
-                pe.receiver->d_func()->removePendingChildInsertedEvents(0);
+                pe.receiver->d_func()->pendingChildInsertedEvents.clear();
 #endif
             pe.event->posted = false;
             events.append(pe.event);
diff --git a/src/corelib/kernel/qobject.cpp b/src/corelib/kernel/qobject.cpp
index 2648e6e..946c8d4 100644
--- a/src/corelib/kernel/qobject.cpp
+++ b/src/corelib/kernel/qobject.cpp
@@ -195,8 +195,8 @@ void QObjectPrivate::sendPendingChildInsertedEvents()
 {
     Q_Q(QObject);
     for (int i = 0; i < pendingChildInsertedEvents.size(); ++i) {
-        QObject *c = pendingChildInsertedEvents.at(i);
-        if (!c)
+        QObject *c = pendingChildInsertedEvents.at(i).data();
+        if (!c || c->parent() != q)
             continue;
         QChildEvent childEvent(QEvent::ChildInserted, c);
         QCoreApplication::sendEvent(q, &childEvent);
@@ -204,26 +204,6 @@ void QObjectPrivate::sendPendingChildInsertedEvents()
     pendingChildInsertedEvents.clear();
 }
 
-void QObjectPrivate::removePendingChildInsertedEvents(QObject *child)
-{
-    if (!child) {
-        pendingChildInsertedEvents.clear();
-        return;
-    }
-
-    // the QObject destructor calls QObject::removeChild, which calls
-    // QCoreApplication::sendEvent() directly.  this can happen while the event
-    // loop is in the middle of posting events, and when we get here, we may
-    // not have any more posted events for this object.
-
-    // if this is a child remove event and the child insert hasn't
-    // been dispatched yet, kill that insert
-    for (int i = 0; i < pendingChildInsertedEvents.size(); ++i) {
-        QObject *&c = pendingChildInsertedEvents[i];
-        if (c == child)
-            c = 0;
-    }
-}
 #endif
 
 
diff --git a/src/corelib/kernel/qobject_p.h b/src/corelib/kernel/qobject_p.h
index 35b4540..82023d4 100644
--- a/src/corelib/kernel/qobject_p.h
+++ b/src/corelib/kernel/qobject_p.h
@@ -55,6 +55,7 @@
 
 #include "QtCore/qobject.h"
 #include "QtCore/qpointer.h"
+#include "QtCore/qsharedpointer.h"
 #include "QtCore/qcoreevent.h"
 #include "QtCore/qlist.h"
 #include "QtCore/qvector.h"
@@ -153,7 +154,6 @@ public:
 
 #ifdef QT3_SUPPORT
     void sendPendingChildInsertedEvents();
-    void removePendingChildInsertedEvents(QObject *child);
 #endif
 
     static inline Sender *setCurrentSender(QObject *receiver,
@@ -186,7 +186,7 @@ public:
     mutable quint32 connectedSignals[2];
 
 #ifdef QT3_SUPPORT
-    QList<QObject *> pendingChildInsertedEvents;
+    QVector< QWeakPointer<QObject> > pendingChildInsertedEvents;
 #else
     // preserve binary compatibility with code compiled without Qt 3 support
     // keeping the binary layout stable helps the Qt Creator debugger
diff --git a/src/gui/kernel/qapplication.cpp b/src/gui/kernel/qapplication.cpp
index 7b62de1..88d81da 100644
--- a/src/gui/kernel/qapplication.cpp
+++ b/src/gui/kernel/qapplication.cpp
@@ -3655,11 +3655,6 @@ bool QApplication::notify(QObject *receiver, QEvent *e)
     d->checkReceiverThread(receiver);
 #endif
 
-#ifdef QT3_SUPPORT
-    if (e->type() == QEvent::ChildRemoved && !receiver->d_func()->pendingChildInsertedEvents.isEmpty())
-        receiver->d_func()->removePendingChildInsertedEvents(static_cast<QChildEvent *>(e)->child());
-#endif // QT3_SUPPORT
-
     // capture the current mouse/keyboard state
     if(e->spontaneous()) {
         if (e->type() == QEvent::KeyPress