winrt: Fix pause/play for videos

This is partially a revert of bff19dbe6733d245. While that commit fixed
switching cameras it did not respect pausing a video, where setActive is
called from a different thread than in the camera case. Using shutdown
introduced a wait, which in that case deadlocked.

Instead revert to request an interrupt, but when restarting make sure
that the render thread is on hold before start is invoked.

Task-number: QTBUG-53722
Change-Id: Id5a722911bb2c30509fabb73bec925cadbf77628
Reviewed-by: Oliver Wolff <oliver.wolff@qt.io>

1 files changed, 9 insertions, 1 deletions

diff --git a/src/plugins/winrt/qwinrtabstractvideorenderercontrol.cpp b/src/plugins/winrt/qwinrtabstractvideorenderercontrol.cpp
index 561d9e03c..b3fd11111 100644
--- a/src/plugins/winrt/qwinrtabstractvideorenderercontrol.cpp
+++ b/src/plugins/winrt/qwinrtabstractvideorenderercontrol.cpp
@@ -356,6 +356,13 @@ void QWinRTAbstractVideoRendererControl::setActive(bool active)
         if (!d->surface)
             return;
 
+        // This only happens for quick restart scenarios, for instance
+        // when switching cameras.
+        if (d->renderThread.isRunning() && d->renderThread.isInterruptionRequested()) {
+            CriticalSectionLocker lock(&d->mutex);
+            d->renderThread.wait();
+        }
+
         if (!d->surface->isActive())
             d->surface->start(d->format);
 
@@ -363,7 +370,8 @@ void QWinRTAbstractVideoRendererControl::setActive(bool active)
         return;
     }
 
-    shutdown();
+    d->renderThread.requestInterruption();
+
     if (d->surface && d->surface->isActive())
         d->surface->stop();
 }