Fix potential crash during shutdown for QQuickWindows

The cleanup() function would deregister the render loop from all
windows the render loop had seen, but the render loop doesn't see
windows until the window gets a showEvent and for some implementations
it was removed as a result of hideEvent. So add explicit tracking to
QSGRenderLoop which is managed by QQuickWindow's constructor and
destructor. With this, we no longer need the lists from the
subclasses, so these functions are removed again.

Change-Id: I05e5507ad57e23c80bacd99752654cc7d0890dc1
Reviewed-by: Paul Olav Tvete <paul.tvete@digia.com>

6 files changed, 6 insertions, 24 deletions

diff --git a/src/quick/scenegraph/qsgrenderloop.cpp b/src/quick/scenegraph/qsgrenderloop.cpp
index bd9c7609ad..f3e879c354 100644
--- a/src/quick/scenegraph/qsgrenderloop.cpp
+++ b/src/quick/scenegraph/qsgrenderloop.cpp
@@ -126,8 +126,6 @@ public:
     QSGContext *sceneGraphContext() const;
     QSGRenderContext *createRenderContext(QSGContext *) const { return rc; }
 
-    QList<QQuickWindow *> windows() const { return m_windows.keys(); }
-
     bool event(QEvent *);
 
     struct WindowData {
diff --git a/src/quick/scenegraph/qsgrenderloop_p.h b/src/quick/scenegraph/qsgrenderloop_p.h
index 47b59992e2..4a22fd60e7 100644
--- a/src/quick/scenegraph/qsgrenderloop_p.h
+++ b/src/quick/scenegraph/qsgrenderloop_p.h
@@ -44,6 +44,7 @@
 
 #include <QtGui/QImage>
 #include <private/qtquickglobal_p.h>
+#include <QtCore/QSet>
 
 QT_BEGIN_NAMESPACE
 
@@ -78,7 +79,9 @@ public:
 
     virtual void releaseResources(QQuickWindow *window) = 0;
 
-    virtual QList<QQuickWindow *> windows() const = 0;
+    void addWindow(QQuickWindow *win) { m_windows.insert(win); }
+    void removeWindow(QQuickWindow *win) { m_windows.remove(win); }
+    QSet<QQuickWindow *> windows() const { return m_windows; }
 
     // ### make this less of a singleton
     static QSGRenderLoop *instance();
@@ -99,6 +102,8 @@ public Q_SLOTS:
 
 private:
     static QSGRenderLoop *s_instance;
+
+    QSet<QQuickWindow *> m_windows;
 };
 
 QT_END_NAMESPACE
diff --git a/src/quick/scenegraph/qsgthreadedrenderloop.cpp b/src/quick/scenegraph/qsgthreadedrenderloop.cpp
index 3dc2a50542..ba8c3a7fce 100644
--- a/src/quick/scenegraph/qsgthreadedrenderloop.cpp
+++ b/src/quick/scenegraph/qsgthreadedrenderloop.cpp
@@ -738,14 +738,6 @@ QSGThreadedRenderLoop::QSGThreadedRenderLoop()
     QSG_GUI_DEBUG((void *) 0, "QSGThreadedRenderLoop() created");
 }
 
-QList<QQuickWindow *> QSGThreadedRenderLoop::windows() const
-{
-    QList<QQuickWindow *> list;
-    foreach (const Window &w, m_windows)
-        list << w.window;
-    return list;
-}
-
 QSGRenderContext *QSGThreadedRenderLoop::createRenderContext(QSGContext *sg) const
 {
     return sg->createRenderContext();
diff --git a/src/quick/scenegraph/qsgthreadedrenderloop_p.h b/src/quick/scenegraph/qsgthreadedrenderloop_p.h
index 3997ef92b7..e142f7f2c8 100644
--- a/src/quick/scenegraph/qsgthreadedrenderloop_p.h
+++ b/src/quick/scenegraph/qsgthreadedrenderloop_p.h
@@ -79,8 +79,6 @@ public:
 
     bool interleaveIncubation() const;
 
-    QList<QQuickWindow *> windows() const;
-
 public Q_SLOTS:
     void animationStarted();
     void animationStopped();
diff --git a/src/quick/scenegraph/qsgwindowsrenderloop.cpp b/src/quick/scenegraph/qsgwindowsrenderloop.cpp
index cbe9ea384b..913b737798 100644
--- a/src/quick/scenegraph/qsgwindowsrenderloop.cpp
+++ b/src/quick/scenegraph/qsgwindowsrenderloop.cpp
@@ -111,15 +111,6 @@ QSGWindowsRenderLoop::~QSGWindowsRenderLoop()
     delete m_sg;
 }
 
-QList<QQuickWindow *> QSGWindowsRenderLoop::windows() const
-{
-    QList<QQuickWindow *> list;
-    foreach (const WindowData &w, m_windows)
-        list << w.window;
-    return list;
-}
-
-
 bool QSGWindowsRenderLoop::interleaveIncubation() const
 {
     return m_animationDriver->isRunning() && anyoneShowing();
diff --git a/src/quick/scenegraph/qsgwindowsrenderloop_p.h b/src/quick/scenegraph/qsgwindowsrenderloop_p.h
index 6c26e728da..e4ee688c9f 100644
--- a/src/quick/scenegraph/qsgwindowsrenderloop_p.h
+++ b/src/quick/scenegraph/qsgwindowsrenderloop_p.h
@@ -86,8 +86,6 @@ public:
 
     bool interleaveIncubation() const;
 
-    QList<QQuickWindow *> windows() const;
-
 public Q_SLOTS:
     void started();
     void stopped();