Revert resource releasing logic inside window managers.

This was based on the assumption that exposure and visibility
would take similar code paths, but this is not the case and
the fallout of this change (like not releasing resources at all)
is not worth it.

This reverts ef6318ae38322b5a4a0619b581924290f114fa74 and most
of 5f0013ee76605b9c7ceab168702b57e797b698e0

Change-Id: Ib2e29972502a8ec956cd6bd294a2a2bb50d8e76e
Reviewed-by: Alan Alpert <alan.alpert@nokia.com>

1 files changed, 37 insertions, 117 deletions

diff --git a/src/quick/items/qquickwindowmanager.cpp b/src/quick/items/qquickwindowmanager.cpp
index b999e6f85d..16b6d92e22 100644
--- a/src/quick/items/qquickwindowmanager.cpp
+++ b/src/quick/items/qquickwindowmanager.cpp
@@ -48,8 +48,8 @@
 #include <QtCore/private/qabstractanimation_p.h>
 
 #include <QtGui/QOpenGLContext>
-#include <QtGui/QPlatformIntegration>
 #include <QtGui/private/qguiapplication_p.h>
+#include <QtGui/qplatformintegration_qpa.h>
 
 #include <QtDeclarative/private/qdeclarativeglobal_p.h>
 
@@ -145,6 +145,10 @@ DEFINE_BOOL_CONFIG_OPTION(qmlNoThreadedRenderer, QML_BAD_GUI_RENDER_LOOP);
 
 //#define THREAD_DEBUG
 
+QQuickWindowManager::~QQuickWindowManager()
+{
+}
+
 class QQuickRenderThreadSingleContextWindowManager : public QThread, public QQuickWindowManager
 {
     Q_OBJECT
@@ -165,7 +169,6 @@ public:
         , shouldExit(false)
         , hasExited(false)
         , isDeferredUpdatePosted(false)
-        , runToReleaseResources(false)
         , canvasToGrab(0)
     {
         sg->moveToThread(this);
@@ -176,13 +179,10 @@ public:
         connect(animationDriver, SIGNAL(stopped()), this, SLOT(animationStopped()));
     }
 
-    ~QQuickRenderThreadSingleContextWindowManager()
-    {
-        releaseResources();
-    }
-
     QSGContext *sceneGraphContext() const { return sg; }
 
+    void releaseResources() { }
+
     void show(QQuickCanvas *canvas);
     void hide(QQuickCanvas *canvas);
 
@@ -201,8 +201,6 @@ public:
     void sync(bool guiAlreadyLocked);
 
     void initialize();
-    void releaseResources();
-    void releaseResourcesInThread();
 
     bool *allowMainThreadProcessing() { return &allowMainThreadProcessingFlag; }
 
@@ -258,7 +256,6 @@ private:
     uint shouldExit : 1;
     uint hasExited : 1;
     uint isDeferredUpdatePosted : 1;
-    uint runToReleaseResources : 1;
 
     QQuickCanvas *canvasToGrab;
     QImage grabContent;
@@ -291,17 +288,12 @@ class QQuickTrivialWindowManager : public QObject, public QQuickWindowManager
 {
 public:
     QQuickTrivialWindowManager();
-    ~QQuickTrivialWindowManager()
-    {
-        releaseResources();
-    }
 
     void show(QQuickCanvas *canvas);
     void hide(QQuickCanvas *canvas);
 
     void canvasDestroyed(QQuickCanvas *canvas);
 
-    void releaseResources();
     void initializeGL();
     void renderCanvas(QQuickCanvas *canvas);
     void paint(QQuickCanvas *canvas);
@@ -310,10 +302,11 @@ public:
 
     void maybeUpdate(QQuickCanvas *canvas);
 
+    void releaseResources() { }
+
     bool *allowMainThreadProcessing();
 
     QSGContext *sceneGraphContext() const;
-    QQuickCanvas *masterCanvas() const;
 
     bool event(QEvent *);
 
@@ -564,18 +557,10 @@ void QQuickRenderThreadSingleContextWindowManager::run()
 #ifdef THREAD_DEBUG
     printf("QML Rendering Thread Started\n");
 #endif
-    lock();
-
-    if (runToReleaseResources) {
-        releaseResourcesInThread();
-        runToReleaseResources = false;
-        unlock();
-        return;
-    }
-
-    if (!gl)
-        initialize();
 
+    lock();
+    Q_ASSERT(!gl);
+    initialize();
     // Wake GUI as it is waiting for the GL context to have appeared, as
     // an indication that the render thread is now running.
     wake();
@@ -772,6 +757,12 @@ void QQuickRenderThreadSingleContextWindowManager::run()
     m_removed_windows << m_rendered_windows.keys();
     handleRemovedWindows();
 
+    sg->invalidate();
+
+    gl->doneCurrent();
+    delete gl;
+    gl = 0;
+
 #ifdef THREAD_DEBUG
     printf("                RenderThread: render loop exited... Good Night!\n");
 #endif
@@ -790,59 +781,6 @@ void QQuickRenderThreadSingleContextWindowManager::run()
 #endif
 }
 
-void QQuickRenderThreadSingleContextWindowManager::releaseResourcesInThread()
-{
-#ifdef THREAD_DEBUG
-    printf("                RenderThread: releasing resources...\n");
-#endif
-    QQuickCanvas *canvas = masterCanvas();
-    QWindow *tmpSurface = 0;
-
-    if (canvas) {
-        gl->makeCurrent(canvas);
-    } else {
-        tmpSurface = new QWindow();
-        tmpSurface->setSurfaceType(QSurface::OpenGLSurface);
-        tmpSurface->resize(4, 4);
-        tmpSurface->create();
-        gl->makeCurrent(tmpSurface);
-    }
-
-    sg->invalidate();
-    gl->doneCurrent();
-    delete gl;
-    gl = 0;
-
-    if (tmpSurface)
-        delete tmpSurface;
-
-    wake();
-}
-
-void QQuickRenderThreadSingleContextWindowManager::releaseResources()
-{
-#ifdef THREAD_DEBUG
-    printf("GUI: releasing resources\n");
-#endif
-
-    lockInGui();
-    if (!isRunning() && gl) {
-        runToReleaseResources = true;
-        start();
-
-        while (isRunning()) {
-            wait();
-        }
-    }
-#ifdef THREAD_DEBUG
-    else {
-        printf("GUI: render thread running not releasing resources...\n");
-    }
-#endif
-    unlockInGui();
-
-}
-
 bool QQuickRenderThreadSingleContextWindowManager::event(QEvent *e)
 {
     Q_ASSERT(QThread::currentThread() == qApp->thread());
@@ -1074,6 +1012,7 @@ void QQuickRenderThreadSingleContextWindowManager::startRendering()
         animationTimer = -1;
     }
 
+
 }
 
 
@@ -1216,46 +1155,17 @@ void QQuickTrivialWindowManager::hide(QQuickCanvas *canvas)
     m_windows.remove(canvas);
     QQuickCanvasPrivate *cd = QQuickCanvasPrivate::get(canvas);
     cd->cleanupNodesOnShutdown();
-}
-
-void QQuickTrivialWindowManager::canvasDestroyed(QQuickCanvas *canvas)
-{
-    hide(canvas);
-}
-
-void QQuickTrivialWindowManager::releaseResources()
-{
-    if (m_windows.size() == 0 && gl) {
-        QQuickCanvas *canvas = masterCanvas();
-        QWindow *tmpSurface = 0;
-
-        if (canvas) {
-            gl->makeCurrent(canvas);
-        } else {
-            tmpSurface = new QWindow();
-            tmpSurface->setSurfaceType(QSurface::OpenGLSurface);
-            tmpSurface->resize(4, 4);
-            tmpSurface->create();
-            gl->makeCurrent(tmpSurface);
-        }
 
+    if (m_windows.size() == 0) {
         sg->invalidate();
         delete gl;
         gl = 0;
-
-        delete tmpSurface;
     }
 }
 
-QQuickCanvas *QQuickTrivialWindowManager::masterCanvas() const
+void QQuickTrivialWindowManager::canvasDestroyed(QQuickCanvas *canvas)
 {
-    // Find a "proper surface" to bind...
-    for (QHash<QQuickCanvas *, CanvasData>::const_iterator it = m_windows.constBegin();
-             it != m_windows.constEnd(); ++it) {
-            if (it.key()->visible())
-                return it.key();
-    }
-    return 0;
+    hide(canvas);
 }
 
 void QQuickTrivialWindowManager::renderCanvas(QQuickCanvas *canvas)
@@ -1265,20 +1175,30 @@ void QQuickTrivialWindowManager::renderCanvas(QQuickCanvas *canvas)
 
     CanvasData &data = const_cast<CanvasData &>(m_windows[canvas]);
 
-    QQuickCanvas *window = canvas->visible() ? canvas : masterCanvas();
+    QQuickCanvas *masterCanvas = 0;
+    if (!canvas->visible()) {
+        // Find a "proper surface" to bind...
+        for (QHash<QQuickCanvas *, CanvasData>::const_iterator it = m_windows.constBegin();
+             it != m_windows.constEnd() && !masterCanvas; ++it) {
+            if (it.key()->visible())
+                masterCanvas = it.key();
+        }
+    } else {
+        masterCanvas = canvas;
+    }
 
-    if (!window)
+    if (!masterCanvas)
         return;
 
     if (!gl) {
         gl = new QOpenGLContext();
-        gl->setFormat(window->requestedFormat());
+        gl->setFormat(masterCanvas->requestedFormat());
         gl->create();
-        if (!gl->makeCurrent(window))
+        if (!gl->makeCurrent(masterCanvas))
             qWarning("QQuickCanvas: makeCurrent() failed...");
         sg->initialize(gl);
     } else {
-        gl->makeCurrent(window);
+        gl->makeCurrent(masterCanvas);
     }
 
     bool alsoSwap = data.updatePending;