Ensure that QOpenGLMultiGroupSharedResources are cleaned up

When a GL context group is destroyed, all multi-group shared
resources associated with the group should be cleaned up.
Otherwise we could get a double deletion in the resource's
destructor, because it still retained a pointer to the
deleted group.

The missing cleanup resulted in a crash when the global
static qt_gl_functions_resource was destroyed, first seen
in the tst_examples autotest in qtdeclarative. It possibly
didn't manifest before because it's event loop-dependent
(the contexts are deleted via deleteLater()).

Change-Id: I6b1e0bfdfbbb2bff8e795f545e680fcdfa094768
Reviewed-by: Samuel Rødal <samuel.rodal@nokia.com>

2 files changed, 13 insertions, 23 deletions

diff --git a/src/gui/kernel/qopenglcontext.cpp b/src/gui/kernel/qopenglcontext.cpp
index 2b2f13e4bd..88925df606 100644
--- a/src/gui/kernel/qopenglcontext.cpp
+++ b/src/gui/kernel/qopenglcontext.cpp
@@ -404,6 +404,15 @@ void QOpenGLContextGroupPrivate::removeContext(QOpenGLContext *ctx)
 
 void QOpenGLContextGroupPrivate::cleanup()
 {
+    Q_Q(QOpenGLContextGroup);
+    {
+        QHash<QOpenGLMultiGroupSharedResource *, QOpenGLSharedResource *>::const_iterator it, end;
+        end = m_resources.constEnd();
+        for (it = m_resources.constBegin(); it != end; ++it)
+            it.key()->cleanup(q, it.value());
+        m_resources.clear();
+    }
+
     QList<QOpenGLSharedResource *>::iterator it = m_sharedResources.begin();
     QList<QOpenGLSharedResource *>::iterator end = m_sharedResources.end();
 
@@ -581,29 +590,15 @@ QList<QOpenGLSharedResource *> QOpenGLMultiGroupSharedResource::resources() cons
     return result;
 }
 
-void QOpenGLMultiGroupSharedResource::cleanup(QOpenGLContext *ctx)
-{
-    QOpenGLSharedResource *resource = value(ctx);
-
-    if (resource != 0) {
-        resource->free();
-
-        QOpenGLContextGroup *group = ctx->shareGroup();
-        group->d_func()->m_resources.remove(this);
-        m_groups.removeOne(group);
-        active.deref();
-    }
-}
-
-void QOpenGLMultiGroupSharedResource::cleanup(QOpenGLContext *ctx, QOpenGLSharedResource *value)
+void QOpenGLMultiGroupSharedResource::cleanup(QOpenGLContextGroup *group, QOpenGLSharedResource *value)
 {
 #ifdef QT_GL_CONTEXT_RESOURCE_DEBUG
-    qDebug("Cleaning up context group resource %p, for context %p in thread %p.", this, ctx, QThread::currentThread());
+    qDebug("Cleaning up context group resource %p, for group %p in thread %p.", this, group, QThread::currentThread());
 #endif
     value->free();
     active.deref();
 
-    QOpenGLContextGroup *group = ctx->shareGroup();
+    Q_ASSERT(m_groups.contains(group));
     m_groups.removeOne(group);
 }
 
diff --git a/src/gui/kernel/qopenglcontext_p.h b/src/gui/kernel/qopenglcontext_p.h
index 059872c09f..1a47d293e5 100644
--- a/src/gui/kernel/qopenglcontext_p.h
+++ b/src/gui/kernel/qopenglcontext_p.h
@@ -138,8 +138,6 @@ public:
 
     QList<QOpenGLSharedResource *> m_sharedResources;
     QList<QOpenGLSharedResource *> m_pendingDeletion;
-
-    void cleanupResources(QOpenGLContext *ctx);
 };
 
 class Q_GUI_EXPORT QOpenGLMultiGroupSharedResource
@@ -149,8 +147,7 @@ public:
     ~QOpenGLMultiGroupSharedResource();
 
     void insert(QOpenGLContext *context, QOpenGLSharedResource *value);
-    void cleanup(QOpenGLContext *context);
-    void cleanup(QOpenGLContext *context, QOpenGLSharedResource *value);
+    void cleanup(QOpenGLContextGroup *group, QOpenGLSharedResource *value);
 
     QOpenGLSharedResource *value(QOpenGLContext *context);
 
@@ -220,8 +217,6 @@ public:
 
     QPaintEngineEx *active_engine;
 
-    QHash<QOpenGLMultiGroupSharedResource *, void *> m_resources;
-
     static void setCurrentContext(QOpenGLContext *context);
 
     int maxTextureSize() const { return 1024; }