PlayerListener: new interface to replace GlobalEvents access

Makefile.am

@@ -137,6 +137,7 @@ libmpd_a_SOURCES = \
 	src/Permission.cxx src/Permission.hxx \
 	src/PlayerThread.cxx src/PlayerThread.hxx \
 	src/PlayerControl.cxx src/PlayerControl.hxx \
+	src/PlayerListener.hxx \
 	src/Playlist.cxx src/Playlist.hxx \
 	src/PlaylistError.cxx src/PlaylistError.hxx \
 	src/PlaylistGlobal.cxx src/PlaylistGlobal.hxx \

src/Partition.cxx

@@ -23,6 +23,7 @@
 #include "output/MultipleOutputs.hxx"
 #include "mixer/Volume.hxx"
 #include "Idle.hxx"
+#include "GlobalEvents.hxx"
 
 #ifdef ENABLE_DATABASE
 
@@ -51,6 +52,18 @@ Partition::SyncWithPlayer()
 }
 
 void
+Partition::OnPlayerSync()
+{
+	GlobalEvents::Emit(GlobalEvents::PLAYLIST);
+}
+
+void
+Partition::OnPlayerTagModified()
+{
+	GlobalEvents::Emit(GlobalEvents::TAG);
+}
+
+void
 Partition::OnMixerVolumeChanged(gcc_unused Mixer &mixer, gcc_unused int volume)
 {
 	InvalidateHardwareVolume();

src/Partition.hxx

@@ -24,6 +24,7 @@
 #include "output/MultipleOutputs.hxx"
 #include "mixer/Listener.hxx"
 #include "PlayerControl.hxx"
+#include "PlayerListener.hxx"
 
 struct Instance;
 class MultipleOutputs;
@@ -33,7 +34,7 @@ class SongLoader;
  * A partition of the Music Player Daemon.  It is a separate unit with
  * a playlist, a player, outputs etc.
  */
-struct Partition final : private MixerListener {
+struct Partition final : private PlayerListener, private MixerListener {
 	Instance &instance;
 
 	struct playlist playlist;
@@ -48,7 +49,7 @@ struct Partition final : private MixerListener {
 		  unsigned buffered_before_play)
 		:instance(_instance), playlist(max_length),
 		 outputs(*this),
-		 pc(outputs, buffer_chunks, buffered_before_play) {}
+		 pc(*this, outputs, buffer_chunks, buffered_before_play) {}
 
 	void ClearQueue() {
 		playlist.Clear(pc);
@@ -192,6 +193,10 @@ struct Partition final : private MixerListener {
 	void SyncWithPlayer();
 
 private:
+	/* virtual methods from class PlayerListener */
+	virtual void OnPlayerSync() override;
+	virtual void OnPlayerTagModified() override;
+
 	/* virtual methods from class MixerListener */
 	virtual void OnMixerVolumeChanged(Mixer &mixer, int volume) override;
 };

src/PlayerControl.cxx

@@ -26,10 +26,11 @@
 
 #include <assert.h>
 
-PlayerControl::PlayerControl(MultipleOutputs &_outputs,
+PlayerControl::PlayerControl(PlayerListener &_listener,
+			     MultipleOutputs &_outputs,
 			     unsigned _buffer_chunks,
 			     unsigned _buffered_before_play)
-	:outputs(_outputs),
+	:listener(_listener), outputs(_outputs),
 	 buffer_chunks(_buffer_chunks),
 	 buffered_before_play(_buffered_before_play),
 	 command(PlayerCommand::NONE),

src/PlayerControl.hxx

@@ -29,6 +29,7 @@
 
 #include <stdint.h>
 
+class PlayerListener;
 class MultipleOutputs;
 class DetachedSong;
 
@@ -92,6 +93,8 @@ struct player_status {
 };
 
 struct PlayerControl {
+	PlayerListener &listener;
+
 	MultipleOutputs &outputs;
 
 	unsigned buffer_chunks;
@@ -137,8 +140,8 @@ struct PlayerControl {
 	 * A copy of the current #DetachedSong after its tags have
 	 * been updated by the decoder (for example, a radio stream
 	 * that has sent a new tag after switching to the next song).
-	 * This shall be used by the GlobalEvents::TAG handler to
-	 * update the current #DetachedSong in the queue.
+	 * This shall be used by PlayerListener::OnPlayerTagModified()
+	 * to update the current #DetachedSong in the queue.
 	 *
 	 * Protected by #mutex.  Set by the PlayerThread and consumed
 	 * by the main thread.
@@ -173,7 +176,8 @@ struct PlayerControl {
 	 */
 	bool border_pause;
 
-	PlayerControl(MultipleOutputs &_outputs,
+	PlayerControl(PlayerListener &_listener,
+		      MultipleOutputs &_outputs,
 		      unsigned buffer_chunks,
 		      unsigned buffered_before_play);
 	~PlayerControl();

src/PlayerListener.hxx

+/*
+ * Copyright (C) 2003-2014 The Music Player Daemon Project
+ * http://www.musicpd.org
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+
+#ifndef MPD_PLAYER_LISTENER_HXX
+#define MPD_PLAYER_LISTENER_HXX
+
+class PlayerListener {
+public:
+	/**
+	 * Must call playlist_sync().
+	 */
+	virtual void OnPlayerSync() = 0;
+
+	/**
+	 * The current song's tag has changed.
+	 */
+	virtual void OnPlayerTagModified() = 0;
+};
+
+#endif

src/PlayerThread.cxx

@@ -19,6 +19,7 @@
 
 #include "config.h"
 #include "PlayerThread.hxx"
+#include "PlayerListener.hxx"
 #include "decoder/DecoderThread.hxx"
 #include "decoder/DecoderControl.hxx"
 #include "MusicPipe.hxx"
@@ -31,7 +32,6 @@
 #include "output/MultipleOutputs.hxx"
 #include "tag/Tag.hxx"
 #include "Idle.hxx"
-#include "GlobalEvents.hxx"
 #include "util/Domain.hxx"
 #include "thread/Name.hxx"
 #include "Log.hxx"
@@ -359,7 +359,7 @@ Player::WaitForDecoder()
 	pc.Unlock();
 
 	/* call syncPlaylistWithQueue() in the main thread */
-	GlobalEvents::Emit(GlobalEvents::PLAYLIST);
+	pc.listener.OnPlayerSync();
 
 	return true;
 }
@@ -696,7 +696,7 @@ update_song_tag(PlayerControl &pc, DetachedSong &song, const Tag &new_tag)
 
 	/* the main thread will update the playlist version when he
 	   receives this event */
-	GlobalEvents::Emit(GlobalEvents::TAG);
+	pc.listener.OnPlayerTagModified();
 
 	/* notify all clients that the tag of the current song has
 	   changed */
@@ -1124,7 +1124,7 @@ player_task(void *arg)
 
 			pc.Unlock();
 			do_play(pc, dc, buffer);
-			GlobalEvents::Emit(GlobalEvents::PLAYLIST);
+			pc.listener.OnPlayerSync();
 			pc.Lock();
 			break;
 

test/run_output.cxx

@@ -53,10 +53,11 @@ filter_plugin_by_name(gcc_unused const char *name)
 	return NULL;
 }
 
-PlayerControl::PlayerControl(gcc_unused MultipleOutputs &_outputs,
+PlayerControl::PlayerControl(PlayerListener &_listener,
+			     MultipleOutputs &_outputs,
 			     gcc_unused unsigned _buffer_chunks,
 			     gcc_unused unsigned _buffered_before_play)
-	:outputs(_outputs) {}
+	:listener(_listener), outputs(_outputs) {}
 PlayerControl::~PlayerControl() {}
 
 static AudioOutput *
@@ -69,7 +70,8 @@ load_audio_output(EventLoop &event_loop, const char *name)
 		return nullptr;
 	}
 
-	static struct PlayerControl dummy_player_control(*(MultipleOutputs *)nullptr,
+	static struct PlayerControl dummy_player_control(*(PlayerListener *)nullptr,
+							 *(MultipleOutputs *)nullptr,
 							 32, 4);
 
 	Error error;