Fix a leak and a crash in designerv5.7.1

This change downports the
56ac0c12ab5e7269e16bcc1248e4241302d91d09
change to the 5.7.1 branch in order to
have a chance for releasing Qt Creator 4.2
with a fix. The crash doesn't appear in
the standalone Designer, it only appears
in the Designer plugin of Qt Creator during reload.
There is no other way to fix that crash
outside of Qt.

Task-number: QTCREATORBUG-17150
Change-Id: Ide521677a1526d3de862d0d8e283531a67b2a7a8
Reviewed-by: Friedemann Kleint <Friedemann.Kleint@qt.io>
(cherry picked from commit 56ac0c12ab5e7269e16bcc1248e4241302d91d09)

3 files changed, 71 insertions, 29 deletions

diff --git a/src/designer/src/lib/shared/formwindowbase.cpp b/src/designer/src/lib/shared/formwindowbase.cpp
index e702d777a..d8f422a0a 100644
--- a/src/designer/src/lib/shared/formwindowbase.cpp
+++ b/src/designer/src/lib/shared/formwindowbase.cpp
@@ -47,6 +47,7 @@
 
 #include <QtCore/qdebug.h>
 #include <QtCore/QList>
+#include <QtCore/QSet>
 #include <QtCore/QTimer>
 #include <QtWidgets/QMenu>
 #include <QtWidgets/QListWidget>
@@ -112,6 +113,15 @@ FormWindowBase::FormWindowBase(QDesignerFormEditorInterface *core, QWidget *pare
 
 FormWindowBase::~FormWindowBase()
 {
+    QSet<QDesignerPropertySheet *> sheets = m_d->m_reloadableResources.keys().toSet();
+    sheets |= m_d->m_reloadablePropertySheets.keys().toSet();
+
+    m_d->m_reloadableResources.clear();
+    m_d->m_reloadablePropertySheets.clear();
+
+    for (QDesignerPropertySheet *sheet : sheets)
+        disconnectSheet(sheet);
+
     delete m_d;
 }
 
@@ -137,14 +147,17 @@ void FormWindowBase::setResourceSet(QtResourceSet *resourceSet)
 
 void FormWindowBase::addReloadableProperty(QDesignerPropertySheet *sheet, int index)
 {
+    connectSheet(sheet);
     m_d->m_reloadableResources[sheet][index] = true;
 }
 
 void FormWindowBase::removeReloadableProperty(QDesignerPropertySheet *sheet, int index)
 {
     m_d->m_reloadableResources[sheet].remove(index);
-    if (m_d->m_reloadableResources[sheet].count() == 0)
+    if (!m_d->m_reloadableResources[sheet].count()) {
         m_d->m_reloadableResources.remove(sheet);
+        disconnectSheet(sheet);
+    }
 }
 
 void FormWindowBase::addReloadablePropertySheet(QDesignerPropertySheet *sheet, QObject *object)
@@ -152,13 +165,53 @@ void FormWindowBase::addReloadablePropertySheet(QDesignerPropertySheet *sheet, Q
     if (qobject_cast<QTreeWidget *>(object) ||
             qobject_cast<QTableWidget *>(object) ||
             qobject_cast<QListWidget *>(object) ||
-            qobject_cast<QComboBox *>(object))
+            qobject_cast<QComboBox *>(object)) {
+        connectSheet(sheet);
         m_d->m_reloadablePropertySheets[sheet] = object;
+    }
 }
 
-void FormWindowBase::removeReloadablePropertySheet(QDesignerPropertySheet *sheet)
+void FormWindowBase::connectSheet(QDesignerPropertySheet *sheet)
 {
-    m_d->m_reloadablePropertySheets.remove(sheet);
+    if (m_d->m_reloadableResources.contains(sheet)
+            || m_d->m_reloadablePropertySheets.contains(sheet)) {
+        // already connected
+        return;
+    }
+    connect(sheet, &QObject::destroyed, this, &FormWindowBase::sheetDestroyed);
+}
+
+void FormWindowBase::disconnectSheet(QDesignerPropertySheet *sheet)
+{
+    if (m_d->m_reloadableResources.contains(sheet)
+            || m_d->m_reloadablePropertySheets.contains(sheet)) {
+        // still need to be connected
+        return;
+    }
+    disconnect(sheet, &QObject::destroyed, this, &FormWindowBase::sheetDestroyed);
+}
+
+void FormWindowBase::sheetDestroyed(QObject *object)
+{
+    // qobject_cast<QDesignerPropertySheet *>(object)
+    // will fail since the destructor of QDesignerPropertySheet
+    // has already finished
+
+    for (auto it = m_d->m_reloadableResources.begin();
+         it != m_d->m_reloadableResources.end(); ++it) {
+        if (it.key() == object) {
+            m_d->m_reloadableResources.erase(it);
+            break;
+        }
+    }
+
+    for (auto it = m_d->m_reloadablePropertySheets.begin();
+         it != m_d->m_reloadablePropertySheets.end(); ++it) {
+        if (it.key() == object) {
+            m_d->m_reloadablePropertySheets.erase(it);
+            break;
+        }
+    }
 }
 
 void FormWindowBase::reloadProperties()
diff --git a/src/designer/src/lib/shared/formwindowbase_p.h b/src/designer/src/lib/shared/formwindowbase_p.h
index 0740e48a6..ceb8beb80 100644
--- a/src/designer/src/lib/shared/formwindowbase_p.h
+++ b/src/designer/src/lib/shared/formwindowbase_p.h
@@ -138,7 +138,6 @@ public:
     void addReloadableProperty(QDesignerPropertySheet *sheet, int index);
     void removeReloadableProperty(QDesignerPropertySheet *sheet, int index);
     void addReloadablePropertySheet(QDesignerPropertySheet *sheet, QObject *object);
-    void removeReloadablePropertySheet(QDesignerPropertySheet *sheet);
     void reloadProperties();
 
     void emitWidgetRemoved(QWidget *w);
@@ -167,9 +166,12 @@ public slots:
 
 private slots:
     void triggerDefaultAction(QWidget *w);
+    void sheetDestroyed(QObject *object);
 
 private:
     void syncGridFeature();
+    void connectSheet(QDesignerPropertySheet *sheet);
+    void disconnectSheet(QDesignerPropertySheet *sheet);
 
     FormWindowBasePrivate *m_d;
 };
diff --git a/src/designer/src/lib/shared/qdesigner_propertysheet.cpp b/src/designer/src/lib/shared/qdesigner_propertysheet.cpp
index 3caaba690..6a0910e2a 100644
--- a/src/designer/src/lib/shared/qdesigner_propertysheet.cpp
+++ b/src/designer/src/lib/shared/qdesigner_propertysheet.cpp
@@ -699,8 +699,6 @@ QDesignerPropertySheet::QDesignerPropertySheet(QObject *object, QObject *parent)
 
 QDesignerPropertySheet::~QDesignerPropertySheet()
 {
-    if (d->m_fwb)
-        d->m_fwb->removeReloadablePropertySheet(this);
     delete d;
 }
 
@@ -1627,8 +1625,6 @@ struct QDesignerAbstractPropertySheetFactory::PropertySheetFactoryPrivate {
 
     typedef QMap<QObject*, QObject*> ExtensionMap;
     ExtensionMap m_extensions;
-    typedef QHash<QObject*, bool> ExtendedSet;
-    ExtendedSet m_extended;
 };
 
 QDesignerAbstractPropertySheetFactory::PropertySheetFactoryPrivate::PropertySheetFactoryPrivate() :
@@ -1653,30 +1649,20 @@ QDesignerAbstractPropertySheetFactory::~QDesignerAbstractPropertySheetFactory()
 
 QObject *QDesignerAbstractPropertySheetFactory::extension(QObject *object, const QString &iid) const
 {
-    typedef PropertySheetFactoryPrivate::ExtensionMap ExtensionMap;
     if (!object)
         return 0;
 
     if (iid != m_impl->m_propertySheetId && iid != m_impl->m_dynamicPropertySheetId)
         return 0;
 
-    ExtensionMap::iterator it = m_impl->m_extensions.find(object);
-    if (it == m_impl->m_extensions.end()) {
-        if (QObject *ext = createPropertySheet(object, const_cast<QDesignerAbstractPropertySheetFactory*>(this))) {
-            connect(ext, &QObject::destroyed, this, &QDesignerAbstractPropertySheetFactory::objectDestroyed);
-            it = m_impl->m_extensions.insert(object, ext);
-        }
-    }
-
-    if (!m_impl->m_extended.contains(object)) {
+    QObject *ext = m_impl->m_extensions.value(object, 0);
+    if (!ext && (ext = createPropertySheet(object, const_cast<QDesignerAbstractPropertySheetFactory*>(this)))) {
+        connect(ext, &QObject::destroyed, this, &QDesignerAbstractPropertySheetFactory::objectDestroyed);
         connect(object, &QObject::destroyed, this, &QDesignerAbstractPropertySheetFactory::objectDestroyed);
-        m_impl->m_extended.insert(object, true);
+        m_impl->m_extensions.insert(object, ext);
     }
 
-    if (it == m_impl->m_extensions.end())
-        return 0;
-
-    return it.value();
+    return ext;
 }
 
 void QDesignerAbstractPropertySheetFactory::objectDestroyed(QObject *object)
@@ -1684,14 +1670,15 @@ void QDesignerAbstractPropertySheetFactory::objectDestroyed(QObject *object)
     QMutableMapIterator<QObject*, QObject*> it(m_impl->m_extensions);
     while (it.hasNext()) {
         it.next();
-
-        QObject *o = it.key();
-        if (o == object || object == it.value()) {
+        if (it.key() == object || it.value() == object) {
+            if (it.key() == object) {
+                QObject *ext = it.value();
+                disconnect(ext, &QObject::destroyed, this, &QDesignerAbstractPropertySheetFactory::objectDestroyed);
+                delete ext;
+            }
             it.remove();
         }
     }
-
-    m_impl->m_extended.remove(object);
 }
 
 QT_END_NAMESPACE