Allow the butler to say "try again later" when get_video() is called

while it's suspended.  Then make the GUI follow that suggestion.
Should

3 files changed, 25 insertions, 4 deletions

diff --git a/src/lib/butler.cc b/src/lib/butler.cc
index a127ee9bd..3e408c4d5 100644
--- a/src/lib/butler.cc
+++ b/src/lib/butler.cc
@@ -190,17 +190,27 @@ try
 }
 
 pair<shared_ptr<PlayerVideo>, DCPTime>
-Butler::get_video ()
+Butler::get_video (Error* e)
 {
 	boost::mutex::scoped_lock lm (_mutex);
 
+	if (_suspended) {
+		if (e) {
+			*e = AGAIN;
+		}
+		return make_pair(shared_ptr<PlayerVideo>(), DCPTime());
+	}
+
 	/* Wait for data if we have none */
 	while (_video.empty() && !_finished && !_died) {
 		_arrived.wait (lm);
 	}
 
 	if (_video.empty()) {
-		return make_pair (shared_ptr<PlayerVideo>(), DCPTime());
+		if (e) {
+			*e = NONE;
+		}
+		return make_pair(shared_ptr<PlayerVideo>(), DCPTime());
 	}
 
 	pair<shared_ptr<PlayerVideo>, DCPTime> const r = _video.get ();
diff --git a/src/lib/butler.h b/src/lib/butler.h
index 4322c401d..fb133d108 100644
--- a/src/lib/butler.h
+++ b/src/lib/butler.h
@@ -41,7 +41,13 @@ public:
 	~Butler ();
 
 	void seek (DCPTime position, bool accurate);
-	std::pair<boost::shared_ptr<PlayerVideo>, DCPTime> get_video ();
+
+	enum Error {
+		NONE,
+		AGAIN
+	};
+
+	std::pair<boost::shared_ptr<PlayerVideo>, DCPTime> get_video (Error* e = 0);
 	boost::optional<DCPTime> get_audio (float* out, Frame frames);
 	boost::optional<TextRingBuffers::Data> get_closed_caption ();
 
diff --git a/src/wx/film_viewer.cc b/src/wx/film_viewer.cc
index 76e269975..d954e1818 100644
--- a/src/wx/film_viewer.cc
+++ b/src/wx/film_viewer.cc
@@ -294,7 +294,12 @@ FilmViewer::get ()
 	DCPOMATIC_ASSERT (_butler);
 
 	do {
-		_player_video = _butler->get_video ();
+		Butler::Error e;
+		_player_video = _butler->get_video (&e);
+		if (!_player_video.first && e == Butler::AGAIN) {
+			signal_manager->when_idle (boost::bind(&FilmViewer::get, this));
+			return;
+		}
 	} while (
 		_player_video.first &&
 		_film->three_d() &&