Don't busy-wait when there's nothing to play.

[dcpomatic.git] / src / wx / video_view.cc

diff --git a/src/wx/video_view.cc b/src/wx/video_view.cc
index 7e9e1a94723b11ff89a90d383494367a1e9cd068..4edc2cd23a28cf0f3b943fe3a9d6cb409fecd973 100644 (file)
--- a/src/wx/video_view.cc
+++ b/src/wx/video_view.cc
@@ -22,8 +22,10 @@
 #include "wx_util.h"
 #include "film_viewer.h"
 #include "lib/butler.h"
+#include <boost/optional.hpp>
 
 using boost::shared_ptr;
+using boost::optional;
 
 VideoView::VideoView (FilmViewer* viewer)
        : _viewer (viewer)
@@ -60,7 +62,9 @@ VideoView::get_next_frame (bool non_blocking)
        }
 
        shared_ptr<Butler> butler = _viewer->butler ();
-       DCPOMATIC_ASSERT (butler);
+       if (!butler) {
+               return false;
+       }
        add_get ();
 
        boost::mutex::scoped_lock lm (_mutex);
@@ -87,13 +91,13 @@ VideoView::one_video_frame () const
        return dcpomatic::DCPTime::from_frames (1, video_frame_rate());
 }
 
-/** @return Time in ms until the next frame is due */
-int
+/** @return Time in ms until the next frame is due, or empty if nothing is due */
+optional<int>
 VideoView::time_until_next_frame () const
 {
        if (length() == dcpomatic::DCPTime()) {
                /* There's no content, so this doesn't matter */
-               return 0;
+               return optional<int>();
        }
 
        dcpomatic::DCPTime const next = position() + one_video_frame();