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>

7 files changed, 108 insertions, 33 deletions

diff --git a/src/plugins/platforms/android/src/androidjnimain.cpp b/src/plugins/platforms/android/src/androidjnimain.cpp
index cd7fa25da7..162a8aa977 100644
--- a/src/plugins/platforms/android/src/androidjnimain.cpp
+++ b/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();
 
@@ -567,13 +566,19 @@ static void setSurface(JNIEnv *env, jobject /*thiz*/, jobject jSurface)
         QWindowSystemInterface::handleScreenAvailableGeometryChange(screen->screen(), geometry);
         QWindowSystemInterface::handleScreenGeometryChange(screen->screen(), geometry);
 
-        if (window != 0) {
-            window->lock();
-            window->scheduleResize(size);
+        // Resize all top level windows, since they share the same surface
+        foreach (QWindow *w, QGuiApplication::topLevelWindows()) {
+            QAndroidOpenGLPlatformWindow *window =
+                    static_cast<QAndroidOpenGLPlatformWindow *>(w->handle());
 
-            QWindowSystemInterface::handleExposeEvent(window->window(),
-                                                      QRegion(window->window()->geometry()));
-            window->unlock();
+            if (window != 0) {
+                window->lock();
+                window->scheduleResize(size);
+
+                QWindowSystemInterface::handleExposeEvent(window->window(),
+                                                          QRegion(window->window()->geometry()));
+                window->unlock();
+            }
         }
 
         m_surfaceMutex.unlock();
diff --git a/src/plugins/platforms/android/src/opengl/qandroidopenglcontext.cpp b/src/plugins/platforms/android/src/opengl/qandroidopenglcontext.cpp
index aa8ee57341..4d741807d0 100644
--- a/src/plugins/platforms/android/src/opengl/qandroidopenglcontext.cpp
+++ b/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();
     }
 }
 
diff --git a/src/plugins/platforms/android/src/opengl/qandroidopenglplatformwindow.cpp b/src/plugins/platforms/android/src/opengl/qandroidopenglplatformwindow.cpp
index 15c6559157..5362906e0e 100644
--- a/src/plugins/platforms/android/src/opengl/qandroidopenglplatformwindow.cpp
+++ b/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()
 {
-    QEglFSWindow::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();
 }
diff --git a/src/plugins/platforms/android/src/opengl/qandroidopenglplatformwindow.h b/src/plugins/platforms/android/src/opengl/qandroidopenglplatformwindow.h
index b835cb3246..36a110e1a8 100644
--- a/src/plugins/platforms/android/src/opengl/qandroidopenglplatformwindow.h
+++ b/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
diff --git a/src/plugins/platforms/android/src/opengl/qeglfshooks_android.cpp b/src/plugins/platforms/android/src/opengl/qeglfshooks_android.cpp
index 4734d47eb3..005758d83d 100644
--- a/src/plugins/platforms/android/src/opengl/qeglfshooks_android.cpp
+++ b/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);
diff --git a/src/plugins/platforms/android/src/qandroidplatformintegration.cpp b/src/plugins/platforms/android/src/qandroidplatformintegration.cpp
index cbd0f26835..3de6c47ad0 100644
--- a/src/plugins/platforms/android/src/qandroidplatformintegration.cpp
+++ b/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
diff --git a/src/plugins/platforms/android/src/qandroidplatformintegration.h b/src/plugins/platforms/android/src/qandroidplatformintegration.h
index 3f8cc5a809..8da9fb2ff4 100644
--- a/src/plugins/platforms/android/src/qandroidplatformintegration.h
+++ b/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;