From cbfaa4a2662c55d7ad6339d70b3665d066bf491a Mon Sep 17 00:00:00 2001
From: Max Kellermann <max@duempel.org>
Date: Wed, 17 Mar 2010 21:57:35 +0100
Subject: [PATCH] player_thread: postpone song tags during cross-fade

Previously, tags of the new song being cross-faded in were sent
immediately.  That can cause wrong information being displayed,
because the "previous" song might send its tag at the end again,
overriding the "next" song's tag.  This patch saves & merges the tag
of the next song, and sends it when cross-fading is finished, and the
next song really starts.
---
 NEWS                |  1 +
 src/player_thread.c | 27 +++++++++++++++++++++++++++
 2 files changed, 28 insertions(+)

diff --git a/NEWS b/NEWS
index 04fa38936..c2c9817ee 100644
--- a/NEWS
+++ b/NEWS
@@ -3,6 +3,7 @@ ver 0.15.9 (2009/??/??)
   - mad: fix crash when seeking at end of song
   - mpcdec: fix negative shift on fixed-point samples
 * playlist: fix single+repeat in random mode
+* player: postpone song tags during cross-fade
 
 
 ver 0.15.8 (2010/01/17)
diff --git a/src/player_thread.c b/src/player_thread.c
index 7fc55d3d1..e2c9b6f93 100644
--- a/src/player_thread.c
+++ b/src/player_thread.c
@@ -89,6 +89,13 @@ struct player {
 	 */
 	unsigned cross_fade_chunks;
 
+	/**
+	 * The tag of the "next" song during cross-fade.  It is
+	 * postponed, and sent to the output thread when the new song
+	 * really begins.
+	 */
+	struct tag *cross_fade_tag;
+
 	/**
 	 * The current audio format for the audio outputs.
 	 */
@@ -518,6 +525,14 @@ play_next_chunk(struct player *player)
 			chunk = music_pipe_shift(player->pipe);
 			assert(chunk != NULL);
 
+			/* don't send the tags of the new song (which
+			   is being faded in) yet; postpone it until
+			   the current song is faded out */
+			player->cross_fade_tag =
+				tag_merge_replace(player->cross_fade_tag,
+						  other_chunk->tag);
+			other_chunk->tag = NULL;
+
 			cross_fade_apply(chunk, other_chunk,
 					 &dc.out_audio_format,
 					 cross_fade_position,
@@ -544,6 +559,14 @@ play_next_chunk(struct player *player)
 
 	assert(chunk != NULL);
 
+	/* insert the postponed tag if cross-fading is finished */
+
+	if (player->xfade != XFADE_ENABLED && player->cross_fade_tag != NULL) {
+		chunk->tag = tag_merge_replace(chunk->tag,
+					       player->cross_fade_tag);
+		player->cross_fade_tag = NULL;
+	}
+
 	/* play the current chunk */
 
 	success = play_chunk(player->song, chunk, &player->play_audio_format,
@@ -608,6 +631,7 @@ static void do_play(void)
 		.xfade = XFADE_UNKNOWN,
 		.cross_fading = false,
 		.cross_fade_chunks = 0,
+		.cross_fade_tag = NULL,
 		.size_to_time = 0.0,
 	};
 
@@ -754,6 +778,9 @@ static void do_play(void)
 	music_pipe_clear(player.pipe, player_buffer);
 	music_pipe_free(player.pipe);
 
+	if (player.cross_fade_tag != NULL)
+		tag_free(player.cross_fade_tag);
+
 	pc.state = PLAYER_STATE_STOP;
 	event_pipe_emit(PIPE_EVENT_PLAYLIST);
 }