Android: clean up Surface resources when it is destroyed

Clean up any resources using the Android Surface when it
has been destroyed. Previously the resource clean up was done
only after Qt app state changed to Hidden or below and we initiate
the removal of the Surface. However, in the case of QtSurface
which is a SurfaceView, it will destroy its Surface before
we ever get to that part, leading to the resources holding
a reference to a destroyed Surface.

Task-number: QTBUG-118231
Change-Id: I282ddcc2813bf0a4e19cbb906376258dd2b4004f
Reviewed-by: Assam Boudjelthia <assam.boudjelthia@qt.io>
(cherry picked from commit 9343d1a)
Reviewed-by: Qt Cherry-pick Bot <cherrypick_bot@qt-project.org>

src/android/jar/src/org/qtproject/qt/android/QtSurface.java

@@ -47,6 +47,8 @@ public void surfaceChanged(SurfaceHolder holder, int format, int width, int heig
     @Override
     public void surfaceDestroyed(SurfaceHolder holder)
     {
+        // Once we return from this function, the Surface will be destroyed,
+        // so everything holding a reference to it needs to clean it up before we do that
         if (m_surfaceCallback != null)
             m_surfaceCallback.onSurfaceChanged(null);
     }

src/plugins/platforms/android/qandroidplatformopenglcontext.cpp

@@ -50,6 +50,12 @@ bool QAndroidPlatformOpenGLContext::makeCurrent(QPlatformSurface *surface)
 
     QAndroidPlatformOpenGLWindow *window = static_cast<QAndroidPlatformOpenGLWindow *>(surface);
     window->lockSurface();
+    // Has the Surface been destroyed?
+    if (window->eglSurface(eglConfig()) == EGL_NO_SURFACE) {
+        qWarning() << "makeCurrent(): no EGLSurface, likely Surface destroyed by Android.";
+        window->unlockSurface();
+        return false;
+    }
     const bool ok = QEGLPlatformContext::makeCurrent(surface);
     window->unlockSurface();
     return ok;

src/plugins/platforms/android/qandroidplatformopenglwindow.cpp

@@ -33,7 +33,7 @@ QAndroidPlatformOpenGLWindow::~QAndroidPlatformOpenGLWindow()
     m_surfaceWaitCondition.wakeOne();
     lockSurface();
     destroySurface();
-    clearEgl();
+    clearSurface();
     unlockSurface();
 }
 
@@ -58,13 +58,15 @@ EGLSurface QAndroidPlatformOpenGLWindow::eglSurface(EGLConfig config)
         QGuiApplication::applicationState() == Qt::ApplicationSuspended) {
         return m_eglSurface;
     }
-
+    // If we haven't called createSurface() yet, call it and wait until Android has created
+    // the Surface
     if (!m_surfaceCreated) {
         AndroidDeadlockProtector protector;
         if (!protector.acquire())
             return m_eglSurface;
 
         createSurface();
+        qCDebug(lcQpaWindow) << "called createSurface(), waiting for Surface to be ready...";
         m_surfaceWaitCondition.wait(&m_surfaceMutex);
     }
 
@@ -79,7 +81,7 @@ EGLSurface QAndroidPlatformOpenGLWindow::eglSurface(EGLConfig config)
 bool QAndroidPlatformOpenGLWindow::checkNativeSurface(EGLConfig config)
 {
     // Either no surface created, or the m_eglSurface already wraps the active Surface
-    // -> makeCurrent is NOT needed.
+    // -> makeCurrent is NOT needed, and we should not create a new EGL surface
     if (!m_surfaceCreated || !m_androidSurfaceObject.isValid())
         return false;
 
@@ -96,14 +98,14 @@ void QAndroidPlatformOpenGLWindow::applicationStateChanged(Qt::ApplicationState
     if (state <=  Qt::ApplicationHidden) {
         lockSurface();
         destroySurface();
-        clearEgl();
+        clearSurface();
         unlockSurface();
     }
 }
 
 void QAndroidPlatformOpenGLWindow::createEgl(EGLConfig config)
 {
-    clearEgl();
+    clearSurface();
     QJniEnvironment env;
     m_nativeWindow = ANativeWindow_fromSurface(env.jniEnv(), m_androidSurfaceObject.object());
     m_androidSurfaceObject = QJniObject();
@@ -124,7 +126,7 @@ QSurfaceFormat QAndroidPlatformOpenGLWindow::format() const
     return m_format;
 }
 
-void QAndroidPlatformOpenGLWindow::clearEgl()
+void QAndroidPlatformOpenGLWindow::clearSurface()
 {
     if (m_eglSurface != EGL_NO_SURFACE) {
         eglMakeCurrent(m_eglDisplay, EGL_NO_SURFACE, EGL_NO_SURFACE, EGL_NO_CONTEXT);
@@ -134,7 +136,7 @@ void QAndroidPlatformOpenGLWindow::clearEgl()
 
     if (m_nativeWindow) {
         ANativeWindow_release(m_nativeWindow);
-        m_nativeWindow = 0;
+        m_nativeWindow = nullptr;
     }
 }
 

src/plugins/platforms/android/qandroidplatformopenglwindow.h

@@ -31,7 +31,7 @@ class QAndroidPlatformOpenGLWindow : public QAndroidPlatformWindow
 
 protected:
     void createEgl(EGLConfig config);
-    void clearEgl();
+    void clearSurface() override;
 
 private:
     EGLDisplay m_eglDisplay = EGL_NO_DISPLAY;

src/plugins/platforms/android/qandroidplatformvulkanwindow.h

@@ -31,8 +31,10 @@ class QAndroidPlatformVulkanWindow : public QAndroidPlatformWindow
 
     VkSurfaceKHR *vkSurface();
 
+protected:
+    void clearSurface() override;
+
 private:
-    void clearSurface();
     void destroyAndClearSurface();
 
     ANativeWindow *m_nativeWindow;

src/plugins/platforms/android/qandroidplatformwindow.cpp

@@ -303,10 +303,14 @@ void QAndroidPlatformWindow::destroySurface()
 void QAndroidPlatformWindow::onSurfaceChanged(QtJniTypes::Surface surface)
 {
     lockSurface();
+    const bool surfaceIsValid = surface.isValid();
+    qCDebug(lcQpaWindow) << "onSurfaceChanged():, valid Surface received" << surfaceIsValid;
     m_androidSurfaceObject = surface;
-    if (m_androidSurfaceObject.isValid()) {
+    if (surfaceIsValid) {
         // wait until we have a valid surface to draw into
         m_surfaceWaitCondition.wakeOne();
+    } else {
+        clearSurface();
     }
 
     unlockSurface();

src/plugins/platforms/android/qandroidplatformwindow.h

@@ -77,6 +77,7 @@ class QAndroidPlatformWindow: public QPlatformWindow
     void sendExpose() const;
     bool blockedByModal() const;
     bool isEmbeddingContainer() const;
+    virtual void clearSurface() {}
 
     Qt::WindowFlags m_windowFlags;
     Qt::WindowStates m_windowState;