Android: Fix crash when using QBackingStore

When making a QBackingStore for a QWindow that was not created yet,
Qt would try to dereference the (null) platform window pointer.

Task-number: QTBUG-31022
Change-Id: I866c71cce9d401ebb598ea4cc91f7cf9bbb30982
Reviewed-by: Samuel Rødal <samuel.rodal@digia.com>
Reviewed-by: Eskil Abrahamsen Blomfeldt <eskil.abrahamsen-blomfeldt@digia.com>

1 files changed, 13 insertions, 0 deletions

diff --git a/src/platformsupport/fbconvenience/qfbscreen.cpp b/src/platformsupport/fbconvenience/qfbscreen.cpp
index 6427b62972..e5b9f09c14 100644
--- a/src/platformsupport/fbconvenience/qfbscreen.cpp
+++ b/src/platformsupport/fbconvenience/qfbscreen.cpp
@@ -71,6 +71,19 @@ void QFbScreen::initializeCompositor()
 void QFbScreen::addWindow(QFbWindow *window)
 {
     mWindowStack.prepend(window);
+    if (!mBackingStores.isEmpty()) {
+        //check if we have a backing store for this window
+        for (int i = 0; i < mBackingStores.size(); ++i) {
+            QFbBackingStore *bs = mBackingStores.at(i);
+            // this gets called during QWindow::create() at a point where the
+            // invariant (window->handle()->window() == window) is broken
+            if (bs->window() == window->window()) {
+                window->setBackingStore(bs);
+                mBackingStores.removeAt(i);
+                break;
+            }
+        }
+    }
     invalidateRectCache();
     setDirty(window->geometry());
     QWindow *w = topWindow();