Fix QtSharedPointer::ExternalRefCountData object leaks

Call destroyObject() for every QV4::Heap::QObectWrapper object in heap in
QV4::MemoryManager::sweep() to make sure the QPointer object contained in
QV4::Heap::QObjectWrapper is properly destructed.
We also keep track of QObjectWrapper in QV4::Heap::ModelObject to make
sure we destory them in QV4::MemoryManager::sweep()

Change-Id: I3b3e96cfc300c2e21ab691762879ac2970afa90c
Reviewed-by: Simon Hausmann <simon.hausmann@theqtcompany.com>

2 files changed, 11 insertions, 2 deletions

diff --git a/src/qml/memory/qv4mm.cpp b/src/qml/memory/qv4mm.cpp
index 5181bf912b..053dfb856c 100644
--- a/src/qml/memory/qv4mm.cpp
+++ b/src/qml/memory/qv4mm.cpp
@@ -41,8 +41,6 @@
 #include "StdLibExtras.h"
 
 #include <QTime>
-#include <QVector>
-#include <QVector>
 #include <QMap>
 
 #include <iostream>
@@ -437,6 +435,15 @@ void MemoryManager::sweep(bool lastSweep)
         (*it) = Primitive::undefinedValue();
     }
 
+    // Some QV4::QObjectWrapper objects will be removed from PersistentValueStorage in WeakValue::~WeakValue()
+    // before MemoryManager::sweep() is being called, in this case we will never have a chance to call detroyObject()
+    // on those QV4::QObjectWrapper objects. Here we call detroyObject() for each pending destroyed Heap::QObjectWrapper
+    // object on the heap to make sure that we can release all the resources held by them
+    for (QVector<Heap::QObjectWrapper *>::const_iterator it = m_pendingDestroyedObjectWrappers.constBegin();
+         it != m_pendingDestroyedObjectWrappers.constEnd(); ++it)
+        QObjectWrapper::destroyObject(*it, lastSweep);
+    m_pendingDestroyedObjectWrappers.clear();
+
     if (MultiplyWrappedQObjectMap *multiplyWrappedQObjects = engine->m_multiplyWrappedQObjects) {
         for (MultiplyWrappedQObjectMap::Iterator it = multiplyWrappedQObjects->begin(); it != multiplyWrappedQObjects->end();) {
             if (!it.value().isNullOrUndefined())
diff --git a/src/qml/memory/qv4mm_p.h b/src/qml/memory/qv4mm_p.h
index 3543da0907..69aae1c5bf 100644
--- a/src/qml/memory/qv4mm_p.h
+++ b/src/qml/memory/qv4mm_p.h
@@ -49,6 +49,7 @@
 #include <private/qv4value_p.h>
 #include <private/qv4scopedvalue_p.h>
 #include <private/qv4object_p.h>
+#include <QVector>
 
 //#define DETAILED_MM_STATS
 
@@ -327,6 +328,7 @@ public:
     QScopedPointer<Data> m_d;
     PersistentValueStorage *m_persistentValues;
     PersistentValueStorage *m_weakValues;
+    QVector<Heap::QObjectWrapper *> m_pendingDestroyedObjectWrappers;
 };
 
 }