Suspend butler on player may-change as otherwise there's a window

between Player::_suspended being set to false and the the butler
requesting a seek, during which the butler may call pass().

4 files changed, 36 insertions, 15 deletions

diff --git a/src/lib/butler.cc b/src/lib/butler.cc
index 386e7f9db..f04b324cd 100644
--- a/src/lib/butler.cc
+++ b/src/lib/butler.cc
@@ -54,6 +54,7 @@ Butler::Butler (shared_ptr<Player> player, shared_ptr<Log> log, AudioMapping aud
 	, _log (log)
 	, _prepare_work (new boost::asio::io_service::work (_prepare_service))
 	, _pending_seek_accurate (false)
+	, _suspended (false)
 	, _finished (false)
 	, _died (false)
 	, _stop_thread (false)
@@ -64,6 +65,7 @@ Butler::Butler (shared_ptr<Player> player, shared_ptr<Log> log, AudioMapping aud
 	_player_video_connection = _player->Video.connect (bind (&Butler::video, this, _1, _2));
 	_player_audio_connection = _player->Audio.connect (bind (&Butler::audio, this, _1, _2));
 	_player_text_connection = _player->Text.connect (bind (&Butler::text, this, _1, _2, _3));
+	_player_may_change_connection = _player->MayChange.connect (bind (&Butler::suspend, this));
 	_player_changed_connection = _player->Changed.connect (bind (&Butler::return_seek, this, _2));
 	_player_not_changed_connection = _player->NotChanged.connect (bind (&Butler::return_seek, this, false));
 	_thread = new boost::thread (bind (&Butler::thread, this));
@@ -105,6 +107,10 @@ Butler::~Butler ()
 bool
 Butler::should_run () const
 {
+	if (_suspended) {
+		return false;
+	}
+
 	if (_video.size() >= MAXIMUM_VIDEO_READAHEAD * 10) {
 		/* This is way too big */
 		throw ProgrammingError
@@ -257,8 +263,8 @@ Butler::video (shared_ptr<PlayerVideo> video, DCPTime time)
 {
 	boost::mutex::scoped_lock lm (_mutex);
 
-	if (_pending_seek_position) {
-		/* Don't store any video while a seek is pending */
+	if (_pending_seek_position || _suspended) {
+		/* Don't store any video in these cases */
 		return;
 	}
 
@@ -273,8 +279,8 @@ Butler::audio (shared_ptr<AudioBuffers> audio, DCPTime time)
 {
 	{
 		boost::mutex::scoped_lock lm (_mutex);
-		if (_pending_seek_position || _disable_audio) {
-			/* Don't store any audio while a seek is pending, or if audio is disabled */
+		if (_pending_seek_position || _disable_audio || _suspended) {
+			/* Don't store any audio in these cases */
 			return;
 		}
 	}
@@ -329,6 +335,7 @@ Butler::return_seek (bool frequent)
 	}
 
 	seek_unlocked (seek_to, true);
+	_suspended = false;
 	_awaiting = seek_to;
 }
 
@@ -342,3 +349,10 @@ Butler::text (PlayerText pt, TextType type, DCPTimePeriod period)
 	boost::mutex::scoped_lock lm2 (_buffers_mutex);
 	_closed_caption.put (make_pair(pt, period));
 }
+
+void
+Butler::suspend ()
+{
+	boost::mutex::scoped_lock lm (_mutex);
+	_suspended = true;
+}
diff --git a/src/lib/butler.h b/src/lib/butler.h
index 56374deeb..6a13ed2d7 100644
--- a/src/lib/butler.h
+++ b/src/lib/butler.h
@@ -56,6 +56,7 @@ private:
 	void text (PlayerText pt, TextType type, DCPTimePeriod period);
 	bool should_run () const;
 	void prepare (boost::weak_ptr<PlayerVideo> video) const;
+	void suspend ();
 	void return_seek (bool frequent);
 	void seek_unlocked (DCPTime position, bool accurate);
 
@@ -83,6 +84,7 @@ private:
 	boost::condition _arrived;
 	boost::optional<DCPTime> _pending_seek_position;
 	bool _pending_seek_accurate;
+	bool _suspended;
 	bool _finished;
 	bool _died;
 	bool _stop_thread;
@@ -100,6 +102,7 @@ private:
 	boost::signals2::scoped_connection _player_video_connection;
 	boost::signals2::scoped_connection _player_audio_connection;
 	boost::signals2::scoped_connection _player_text_connection;
+	boost::signals2::scoped_connection _player_may_change_connection;
 	boost::signals2::scoped_connection _player_changed_connection;
 	boost::signals2::scoped_connection _player_not_changed_connection;
 };
diff --git a/src/lib/player.cc b/src/lib/player.cc
index 91f1cb517..df8c47cf9 100644
--- a/src/lib/player.cc
+++ b/src/lib/player.cc
@@ -87,7 +87,7 @@ int const PlayerProperty::DCP_DECODE_REDUCTION = 704;
 Player::Player (shared_ptr<const Film> film, shared_ptr<const Playlist> playlist)
 	: _film (film)
 	, _playlist (playlist)
-	, _can_run (false)
+	, _suspended (false)
 	, _ignore_video (false)
 	, _ignore_audio (false)
 	, _ignore_text (false)
@@ -220,7 +220,7 @@ Player::setup_pieces_unlocked ()
 	_last_video_time = DCPTime ();
 	_last_video_eyes = EYES_BOTH;
 	_last_audio_time = DCPTime ();
-	_can_run = true;
+	_suspended = false;
 }
 
 void
@@ -232,7 +232,7 @@ Player::playlist_content_may_change ()
 		   until that has happened and we've rebuilt our pieces.  Stop pass()
 		   and seek() from working until then.
 		*/
-		_can_run = false;
+		_suspended = true;
 	}
 
 	MayChange ();
@@ -295,7 +295,6 @@ void
 Player::playlist_content_not_changed ()
 {
 	/* A possible content change did end up happening for some reason */
-	setup_pieces ();
 	NotChanged ();
 }
 
@@ -613,7 +612,7 @@ Player::pass ()
 {
 	boost::mutex::scoped_lock lm (_mutex);
 
-	if (!_can_run) {
+	if (_suspended) {
 		/* We can't pass in this state */
 		return false;
 	}
@@ -1039,7 +1038,7 @@ Player::seek (DCPTime time, bool accurate)
 {
 	boost::mutex::scoped_lock lm (_mutex);
 
-	if (!_can_run) {
+	if (_suspended) {
 		/* We can't seek in this state */
 		return;
 	}
diff --git a/src/lib/player.h b/src/lib/player.h
index c43cfd40e..f7ab1000d 100644
--- a/src/lib/player.h
+++ b/src/lib/player.h
@@ -88,16 +88,21 @@ public:
 
 	boost::optional<DCPTime> content_time_to_dcp (boost::shared_ptr<Content> content, ContentTime t);
 
+	/* The player's internal state may be about to change such so
+	   that its emissions from Video and Audio will suddenly be
+	   from an undefined position.  Listeners should prepare
+	   themselves for this possibility.
+	*/
 	boost::signals2::signal<void ()> MayChange;
 
-	/** Emitted when something has changed such that if we went back and emitted
-	 *  the last frame again it would look different.  This is not emitted after
-	 *  a seek.
+	/** The player's internal state has now changed.
 	 *
 	 *  The first parameter is what changed.
 	 *  The second parameter is true if these signals are currently likely to be frequent.
 	 */
 	boost::signals2::signal<void (int, bool)> Changed;
+
+	/** The change suggested by a MayChange did not happen */
 	boost::signals2::signal<void ()> NotChanged;
 
 	/** Emitted when a video frame is ready.  These emissions happen in the correct order. */
@@ -156,8 +161,8 @@ private:
 	boost::shared_ptr<const Film> _film;
 	boost::shared_ptr<const Playlist> _playlist;
 
-	/** We can pass() and seek() */
-	bool _can_run;
+	/** true if we are suspended (i.e. pass() and seek() do nothing */
+	bool _suspended;
 	std::list<boost::shared_ptr<Piece> > _pieces;
 
 	/** Size of the image in the DCP (e.g. 1990x1080 for flat) */