Android: Don't crash when displaying multiple top-levels

While the raster platform plugin supports multiple top
level windows, this is not supported on the GL plugin,
so if you use GL or QtQuick2 in your app and use several
top levels, the app would crash with an error message.

A problem is that the top-level SurfaceView is a special
overlay View and does not support being stacked in a
layout. So instead, we let all windows share the same
GL surface and draw on top of each other. This works
fine for simple use cases.

We implement a new platform capability to make sure no
top level windows (even combobox popups and dialogs)
get non-fullscreen geometries. That has never
worked properly with the eglfs plugin.

Task-number: QTBUG-30473
Change-Id: Ia1438019638fc739cc93ffe79b46b81631254df2
Reviewed-by: Paul Olav Tvete <paul.tvete@digia.com>

src/gui/kernel/qplatformintegration.cpp

@@ -210,6 +210,11 @@ QPlatformServices *QPlatformIntegration::services() const
     \value ForeignWindows The platform allows creating QWindows which represent
     native windows created by other processes or anyway created by using native
     libraries.
+
+    \value NonFullScreenWindows The platform supports top-level windows which do not
+    fill the screen. The default implementation returns true. Returning false for
+    this will cause all windows, including dialogs and popups, to be resized to fill the
+    screen.
  */
 
 
@@ -227,8 +232,7 @@ QPlatformServices *QPlatformIntegration::services() const
 
 bool QPlatformIntegration::hasCapability(Capability cap) const
 {
-    Q_UNUSED(cap);
-    return false;
+    return cap == NonFullScreenWindows;
 }
 
 QPlatformPixmap *QPlatformIntegration::createPlatformPixmap(QPlatformPixmap::PixelType type) const

src/gui/kernel/qplatformintegration.h

@@ -90,7 +90,8 @@ public:
         WindowMasks,
         MultipleWindows,
         ApplicationState,
-        ForeignWindows
+        ForeignWindows,
+        NonFullScreenWindows
     };
 
     virtual ~QPlatformIntegration() { }

src/plugins/platforms/android/src/androidjnimain.cpp

@@ -559,7 +559,6 @@ static void setSurface(JNIEnv *env, jobject /*thiz*/, jobject jSurface)
         m_surfaceMutex.unlock();
         m_androidPlatformIntegration->surfaceChanged();
     } else if (m_androidPlatformIntegration && sameNativeWindow) {
-        QAndroidOpenGLPlatformWindow *window = m_androidPlatformIntegration->primaryWindow();
         QPlatformScreen *screen = m_androidPlatformIntegration->screen();
         QSize size = QtAndroid::nativeWindowSize();
 
@@ -567,6 +566,11 @@ static void setSurface(JNIEnv *env, jobject /*thiz*/, jobject jSurface)
         QWindowSystemInterface::handleScreenAvailableGeometryChange(screen->screen(), geometry);
         QWindowSystemInterface::handleScreenGeometryChange(screen->screen(), geometry);
 
+        // Resize all top level windows, since they share the same surface
+        foreach (QWindow *w, QGuiApplication::topLevelWindows()) {
+            QAndroidOpenGLPlatformWindow *window =
+                    static_cast<QAndroidOpenGLPlatformWindow *>(w->handle());
+
             if (window != 0) {
                 window->lock();
                 window->scheduleResize(size);
@@ -575,6 +579,7 @@ static void setSurface(JNIEnv *env, jobject /*thiz*/, jobject jSurface)
                                                           QRegion(window->window()->geometry()));
                 window->unlock();
             }
+        }
 
         m_surfaceMutex.unlock();
     } else {

src/plugins/platforms/android/src/opengl/qandroidopenglcontext.cpp

@@ -62,16 +62,16 @@ void QAndroidOpenGLContext::swapBuffers(QPlatformSurface *surface)
 {
     QEglFSContext::swapBuffers(surface);
 
-    QAndroidOpenGLPlatformWindow *primaryWindow = m_platformIntegration->primaryWindow();
-    if (primaryWindow == surface) {
-        primaryWindow->lock();
-        QSize size = primaryWindow->scheduledResize();
+    if (surface->surface()->surfaceClass() == QSurface::Window) {
+        QAndroidOpenGLPlatformWindow *window = static_cast<QAndroidOpenGLPlatformWindow *>(surface);
+        window->lock();
+        QSize size = window->scheduledResize();
         if (size.isValid()) {
             QRect geometry(QPoint(0, 0), size);
-            primaryWindow->setGeometry(geometry);
-            primaryWindow->scheduleResize(QSize());
+            window->setGeometry(geometry);
+            window->scheduleResize(QSize());
         }
-        primaryWindow->unlock();
+        window->unlock();
     }
 }
 

src/plugins/platforms/android/src/opengl/qandroidopenglplatformwindow.cpp

@@ -45,11 +45,21 @@
 
 QT_BEGIN_NAMESPACE
 
+EGLSurface QAndroidOpenGLPlatformWindow::m_staticSurface = 0;
+EGLNativeWindowType QAndroidOpenGLPlatformWindow::m_staticNativeWindow = 0;
+QReadWriteLock QAndroidOpenGLPlatformWindow::m_staticSurfaceLock;
+QBasicAtomicInt QAndroidOpenGLPlatformWindow::m_referenceCount = Q_BASIC_ATOMIC_INITIALIZER(0);
+
 QAndroidOpenGLPlatformWindow::QAndroidOpenGLPlatformWindow(QWindow *window)
     : QEglFSWindow(window)
 {
 }
 
+QAndroidOpenGLPlatformWindow::~QAndroidOpenGLPlatformWindow()
+{
+    destroy();
+}
+
 bool QAndroidOpenGLPlatformWindow::isExposed() const
 {
     return QtAndroid::nativeWindow(false) != 0 && QEglFSWindow::isExposed();
@@ -60,11 +70,57 @@ void QAndroidOpenGLPlatformWindow::invalidateSurface()
     QWindowSystemInterface::handleExposeEvent(window(), QRegion()); // Obscure event
     QWindowSystemInterface::flushWindowSystemEvents();
     QEglFSWindow::invalidateSurface();
+
+    m_window = 0;
+    m_surface = 0;
+
+    if (!m_referenceCount.deref()){
+        QWriteLocker locker(&m_staticSurfaceLock);
+
+        EGLDisplay display = (static_cast<QEglFSScreen *>(window()->screen()->handle()))->display();
+        eglDestroySurface(display, m_staticSurface);
+
+        m_staticSurface = 0;
+        m_staticNativeWindow = 0;
+    }
 }
 
 void QAndroidOpenGLPlatformWindow::resetSurface()
 {
+    m_referenceCount.ref();
+    if (m_staticSurface == 0) {
+        QWriteLocker locker(&m_staticSurfaceLock);
         QEglFSWindow::resetSurface();
+        m_staticSurface = m_surface;
+        m_staticNativeWindow = m_window;
+    } else {
+        QReadLocker locker(&m_staticSurfaceLock);
+        Q_ASSERT(m_staticSurface != m_surface);
+        m_window = m_staticNativeWindow;
+        m_surface = m_staticSurface;
+    }
+
+    QWindowSystemInterface::handleExposeEvent(window(), QRegion(geometry())); // Expose event
+    QWindowSystemInterface::flushWindowSystemEvents();
+}
+
+void QAndroidOpenGLPlatformWindow::destroy()
+{
+    if (!m_referenceCount.deref()) {
+        QEglFSWindow::destroy();
+    } else {
+        m_window = 0;
+        m_surface = 0;
+    }
+}
+
+void QAndroidOpenGLPlatformWindow::raise()
+{
+}
+
+void QAndroidOpenGLPlatformWindow::setVisible(bool visible)
+{
+    QEglFSWindow::setVisible(visible);
     QWindowSystemInterface::handleExposeEvent(window(), QRegion(geometry())); // Expose event
     QWindowSystemInterface::flushWindowSystemEvents();
 }

src/plugins/platforms/android/src/opengl/qandroidopenglplatformwindow.h

@@ -44,6 +44,7 @@
 
 #include "qeglfswindow.h"
 #include <QtCore/qmutex.h>
+#include <QtCore/qreadwritelock.h>
 
 QT_BEGIN_NAMESPACE
 
@@ -51,6 +52,7 @@ class QAndroidOpenGLPlatformWindow : public QEglFSWindow
 {
 public:
     QAndroidOpenGLPlatformWindow(QWindow *window);
+    ~QAndroidOpenGLPlatformWindow();
 
     QSize scheduledResize() const { return m_scheduledResize; }
     void scheduleResize(const QSize &size) { m_scheduledResize = size; }
@@ -60,12 +62,23 @@ public:
 
     bool isExposed() const;
 
+    void raise();
+
     void invalidateSurface();
     void resetSurface();
 
+    void setVisible(bool visible);
+
+    void destroy();
+
 private:
     QSize m_scheduledResize;
     QMutex m_lock;
+
+    static QReadWriteLock m_staticSurfaceLock;
+    static EGLSurface m_staticSurface;
+    static EGLNativeWindowType m_staticNativeWindow;
+    static QBasicAtomicInt m_referenceCount;
 };
 
 QT_END_NAMESPACE

src/plugins/platforms/android/src/opengl/qeglfshooks_android.cpp

@@ -96,6 +96,7 @@ QDpi QEglFSAndroidHooks::logicalDpi() const
 
 EGLNativeWindowType QEglFSAndroidHooks::createNativeWindow(const QSize &size, const QSurfaceFormat &format)
 {
+    Q_UNUSED(size);
     ANativeWindow *window = QtAndroid::nativeWindow();
     if (window != 0)
         ANativeWindow_acquire(window);

src/plugins/platforms/android/src/qandroidplatformintegration.cpp

@@ -43,6 +43,7 @@
 #include "qabstracteventdispatcher.h"
 #include "androidjnimain.h"
 #include <QtGui/private/qpixmap_raster_p.h>
+#include <QtGui/qguiapplication.h>
 #include <qpa/qwindowsysteminterface.h>
 #include <QThread>
 #include <qpa/qplatformwindow.h>
@@ -85,9 +86,6 @@ void *QAndroidPlatformNativeInterface::nativeResourceForIntegration(const QByteA
 
 QAndroidPlatformIntegration::QAndroidPlatformIntegration(const QStringList &paramList)
     : m_touchDevice(0)
-#ifdef ANDROID_PLUGIN_OPENGL
-    , m_primaryWindow(0)
-#endif
 {
     Q_UNUSED(paramList);
 
@@ -116,6 +114,7 @@ bool QAndroidPlatformIntegration::hasCapability(Capability cap) const
 {
     switch (cap) {
         case ThreadedPixmaps: return true;
+        case NonFullScreenWindows: return false;
         default:
 #ifndef ANDROID_PLUGIN_OPENGL
         return QPlatformIntegration::hasCapability(cap);
@@ -143,28 +142,32 @@ QAbstractEventDispatcher *QAndroidPlatformIntegration::guiThreadEventDispatcher(
 #else // !ANDROID_PLUGIN_OPENGL
 QPlatformWindow *QAndroidPlatformIntegration::createPlatformWindow(QWindow *window) const
 {
-    if (m_primaryWindow != 0) {
-        qWarning("QAndroidPlatformIntegration::createPlatformWindow: Unsupported case: More than "
-                 "one top-level window created.");
-    }
-
-    m_primaryWindow = new QAndroidOpenGLPlatformWindow(window);
-    m_primaryWindow->requestActivateWindow();
+    QAndroidOpenGLPlatformWindow *platformWindow = new QAndroidOpenGLPlatformWindow(window);
+    platformWindow->create();
+    platformWindow->requestActivateWindow();
     QtAndroidMenu::setActiveTopLevelWindow(window);
 
-    return m_primaryWindow;
+    return platformWindow;
 }
 
 void QAndroidPlatformIntegration::invalidateNativeSurface()
 {
-    if (m_primaryWindow != 0)
-        m_primaryWindow->invalidateSurface();
+    foreach (QWindow *w, QGuiApplication::topLevelWindows()) {
+        QAndroidOpenGLPlatformWindow *window =
+                static_cast<QAndroidOpenGLPlatformWindow *>(w->handle());
+        if (window != 0)
+            window->invalidateSurface();
+    }
 }
 
 void QAndroidPlatformIntegration::surfaceChanged()
 {
-    if (m_primaryWindow != 0)
-        m_primaryWindow->resetSurface();
+    foreach (QWindow *w, QGuiApplication::topLevelWindows()) {
+        QAndroidOpenGLPlatformWindow *window =
+                static_cast<QAndroidOpenGLPlatformWindow *>(w->handle());
+        if (window != 0)
+            window->resetSurface();
+    }
 }
 
 QPlatformOpenGLContext *QAndroidPlatformIntegration::createPlatformOpenGLContext(QOpenGLContext *context) const

src/plugins/platforms/android/src/qandroidplatformintegration.h

@@ -95,7 +95,6 @@ public:
     QPlatformWindow *createPlatformWindow(QWindow *window) const;
     void invalidateNativeSurface();
     void surfaceChanged();
-    QAndroidOpenGLPlatformWindow *primaryWindow() const { return m_primaryWindow; }
     QPlatformOpenGLContext *createPlatformOpenGLContext(QOpenGLContext *context) const;
 #endif
 
@@ -138,8 +137,6 @@ private:
 #ifndef ANDROID_PLUGIN_OPENGL
     QAbstractEventDispatcher *m_eventDispatcher;
     QAndroidPlatformScreen *m_primaryScreen;
-#else
-    mutable QAndroidOpenGLPlatformWindow *m_primaryWindow;
 #endif
 
     QThread *m_mainThread;

src/widgets/kernel/qwidget_qpa.cpp

@@ -52,6 +52,7 @@
 #include <qpa/qplatformopenglcontext.h>
 #include <qpa/qplatformintegration.h>
 #include "QtGui/private/qwindow_p.h"
+#include "QtGui/private/qguiapplication_p.h"
 
 #include <qpa/qplatformcursor.h>
 #include <QtGui/QGuiApplication>
@@ -675,6 +676,16 @@ void QWidgetPrivate::setGeometry_sys(int x, int y, int w, int h, bool isMove)
         h = qMax(h,extra->minh);
     }
 
+    if (q->isWindow() && q->windowHandle()) {
+        QPlatformIntegration *integration = QGuiApplicationPrivate::platformIntegration();
+        if (!integration->hasCapability(QPlatformIntegration::NonFullScreenWindows)) {
+            x = 0;
+            y = 0;
+            w = q->windowHandle()->width();
+            h = q->windowHandle()->height();
+        }
+    }
+
     QPoint oldp = q->geometry().topLeft();
     QSize olds = q->size();
     QRect r(x, y, w, h);
@@ -720,7 +731,7 @@ void QWidgetPrivate::setGeometry_sys(int x, int y, int w, int h, bool isMove)
                     q->windowHandle()->setGeometry(QRect(posInNativeParent,r.size()));
                 }
                 const QWidgetBackingStore *bs = maybeBackingStore();
-                if (bs->store) {
+                if (bs && bs->store) {
                     if (isResize)
                         bs->store->resize(r.size());
                 }