Merge remote-tracking branch 'origin/5.7' into dev

Conflicts:
	mkspecs/common/mac.conf
	mkspecs/features/configure_base.prf
	mkspecs/features/configure.prf
	mkspecs/macx-clang-32/qmake.conf
	mkspecs/macx-clang/qmake.conf
	mkspecs/macx-ios-clang/qmake.conf
	src/network/ssl/qsslsocket_openssl_symbols_p.h

Change-Id: I768b592e8e589662b1fdb9b8cbd633fef26845b6

2 files changed, 6 insertions, 21 deletions

diff --git a/src/plugins/platforms/ios/qioscontext.mm b/src/plugins/platforms/ios/qioscontext.mm
index d18e317bfb..50374dc951 100644
--- a/src/plugins/platforms/ios/qioscontext.mm
+++ b/src/plugins/platforms/ios/qioscontext.mm
@@ -217,8 +217,12 @@ void QIOSContext::swapBuffers(QPlatformSurface *surface)
     if (surface->surface()->surfaceClass() == QSurface::Offscreen)
         return; // Nothing to do
 
+    // When using threaded rendering, the render-thread may not have picked up
+    // yet on the fact that a window is no longer exposed, and will try to swap
+    // a non-exposed window. This may in some cases result in crashes, e.g. when
+    // iOS is suspending an application, so we have an extra guard here.
     if (!static_cast<QIOSWindow *>(surface)->isExposed()) {
-        qCWarning(lcQpaGLContext, "Detected swapBuffers on a non-exposed window, skipping flush");
+        qCDebug(lcQpaGLContext, "Detected swapBuffers on a non-exposed window, skipping flush");
         return;
     }
 
diff --git a/src/plugins/platforms/ios/qioswindow.mm b/src/plugins/platforms/ios/qioswindow.mm
index 2805eaa304..cddfbe6b06 100644
--- a/src/plugins/platforms/ios/qioswindow.mm
+++ b/src/plugins/platforms/ios/qioswindow.mm
@@ -223,26 +223,7 @@ void QIOSWindow::applyGeometry(const QRect &rect)
 
 bool QIOSWindow::isExposed() const
 {
-    // Note: At startup of an iOS app it will enter UIApplicationStateInactive
-    // while showing the launch screen, and once the application returns from
-    // applicationDidFinishLaunching it will hide the launch screen and enter
-    // UIApplicationStateActive. Technically, a window is not exposed until
-    // it's actually visible on screen, and Apple also documents that "Apps
-    // that use OpenGL ES for drawing must not use didFinishLaunching to
-    // prepare their drawing environment. Instead, defer any OpenGL ES
-    // drawing calls to applicationDidBecomeActive". Unfortunately, if we
-    // wait until the applicationState reaches ApplicationActive to signal
-    // that the window is exposed, we get a lag between hiding the launch
-    // screen and blitting the first pixels of the application, as Qt
-    // spends some time drawing those pixels in response to the expose.
-    // In practice there doesn't seem to be any issues starting GL setup
-    // and drawing from within applicationDidFinishLaunching, and this is
-    // also the recommended approach for other 3rd party GL toolkits on iOS,
-    // so we 'cheat', and report that a window is exposed even if the app
-    // is in UIApplicationStateInactive, so that the startup transition
-    // between the launch screen and the application content is smooth.
-
-    return qApp->applicationState() > Qt::ApplicationHidden
+    return qApp->applicationState() >= Qt::ApplicationActive
         && window()->isVisible() && !window()->geometry().isEmpty();
 }