{decoder,player}_thread: convert to C++

1 files changed, 1198 insertions, 0 deletions

diff --git a/src/PlayerThread.cxx b/src/PlayerThread.cxx
new file mode 100644
index 00000000..ad7a008d
--- /dev/null
+++ b/src/PlayerThread.cxx
@@ -0,0 +1,1198 @@
+/*
+ * Copyright (C) 2003-2013 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.
+ */
+
+#include "config.h"
+#include "PlayerThread.hxx"
+#include "DecoderThread.hxx"
+#include "song.h"
+#include "Main.hxx"
+#include "mpd_error.h"
+
+extern "C" {
+#include "player_control.h"
+#include "decoder_control.h"
+#include "output_all.h"
+#include "event_pipe.h"
+#include "crossfade.h"
+#include "tag.h"
+#include "pipe.h"
+#include "chunk.h"
+#include "idle.h"
+#include "buffer.h"
+}
+
+#include <glib.h>
+
+#undef G_LOG_DOMAIN
+#define G_LOG_DOMAIN "player_thread"
+
+enum xfade_state {
+	XFADE_DISABLED = -1,
+	XFADE_UNKNOWN = 0,
+	XFADE_ENABLED = 1
+};
+
+struct player {
+	struct player_control *pc;
+
+	struct decoder_control *dc;
+
+	struct music_pipe *pipe;
+
+	/**
+	 * are we waiting for buffered_before_play?
+	 */
+	bool buffering;
+
+	/**
+	 * true if the decoder is starting and did not provide data
+	 * yet
+	 */
+	bool decoder_starting;
+
+	/**
+	 * is the player paused?
+	 */
+	bool paused;
+
+	/**
+	 * is there a new song in pc.next_song?
+	 */
+	bool queued;
+
+	/**
+	 * Was any audio output opened successfully?  It might have
+	 * failed meanwhile, but was not explicitly closed by the
+	 * player thread.  When this flag is unset, some output
+	 * methods must not be called.
+	 */
+	bool output_open;
+
+	/**
+	 * the song currently being played
+	 */
+	struct song *song;
+
+	/**
+	 * is cross fading enabled?
+	 */
+	enum xfade_state xfade;
+
+	/**
+	 * has cross-fading begun?
+	 */
+	bool cross_fading;
+
+	/**
+	 * The number of chunks used for crossfading.
+	 */
+	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.
+	 */
+	struct audio_format play_audio_format;
+
+	/**
+	 * The time stamp of the chunk most recently sent to the
+	 * output thread.  This attribute is only used if
+	 * audio_output_all_get_elapsed_time() didn't return a usable
+	 * value; the output thread can estimate the elapsed time more
+	 * precisely.
+	 */
+	float elapsed_time;
+
+	player(player_control *_pc, decoder_control *_dc)
+		:pc(_pc), dc(_dc),
+		 buffering(false),
+		 decoder_starting(false),
+		 paused(false),
+		 queued(true),
+		 output_open(false),
+		 song(NULL),
+		 xfade(XFADE_UNKNOWN),
+		 cross_fading(false),
+		 cross_fade_chunks(0),
+		 cross_fade_tag(NULL),
+		 elapsed_time(0.0) {}
+};
+
+static struct music_buffer *player_buffer;
+
+static void
+player_command_finished_locked(struct player_control *pc)
+{
+	assert(pc->command != PLAYER_COMMAND_NONE);
+
+	pc->command = PLAYER_COMMAND_NONE;
+	g_cond_signal(main_cond);
+}
+
+static void
+player_command_finished(struct player_control *pc)
+{
+	player_lock(pc);
+	player_command_finished_locked(pc);
+	player_unlock(pc);
+}
+
+/**
+ * Start the decoder.
+ *
+ * Player lock is not held.
+ */
+static void
+player_dc_start(struct player *player, struct music_pipe *pipe)
+{
+	struct player_control *pc = player->pc;
+	struct decoder_control *dc = player->dc;
+
+	assert(player->queued || pc->command == PLAYER_COMMAND_SEEK);
+	assert(pc->next_song != NULL);
+
+	unsigned start_ms = pc->next_song->start_ms;
+	if (pc->command == PLAYER_COMMAND_SEEK)
+		start_ms += (unsigned)(pc->seek_where * 1000);
+
+	dc_start(dc, song_dup_detached(pc->next_song),
+		 start_ms, pc->next_song->end_ms,
+		 player_buffer, pipe);
+}
+
+/**
+ * Is the decoder still busy on the same song as the player?
+ *
+ * Note: this function does not check if the decoder is already
+ * finished.
+ */
+static bool
+player_dc_at_current_song(const struct player *player)
+{
+	assert(player != NULL);
+	assert(player->pipe != NULL);
+
+	return player->dc->pipe == player->pipe;
+}
+
+/**
+ * Returns true if the decoder is decoding the next song (or has begun
+ * decoding it, or has finished doing it), and the player hasn't
+ * switched to that song yet.
+ */
+static bool
+player_dc_at_next_song(const struct player *player)
+{
+	return player->dc->pipe != NULL && !player_dc_at_current_song(player);
+}
+
+/**
+ * Stop the decoder and clears (and frees) its music pipe.
+ *
+ * Player lock is not held.
+ */
+static void
+player_dc_stop(struct player *player)
+{
+	struct decoder_control *dc = player->dc;
+
+	dc_stop(dc);
+
+	if (dc->pipe != NULL) {
+		/* clear and free the decoder pipe */
+
+		music_pipe_clear(dc->pipe, player_buffer);
+
+		if (dc->pipe != player->pipe)
+			music_pipe_free(dc->pipe);
+
+		dc->pipe = NULL;
+	}
+}
+
+/**
+ * After the decoder has been started asynchronously, wait for the
+ * "START" command to finish.  The decoder may not be initialized yet,
+ * i.e. there is no audio_format information yet.
+ *
+ * The player lock is not held.
+ */
+static bool
+player_wait_for_decoder(struct player *player)
+{
+	struct player_control *pc = player->pc;
+	struct decoder_control *dc = player->dc;
+
+	assert(player->queued || pc->command == PLAYER_COMMAND_SEEK);
+	assert(pc->next_song != NULL);
+
+	player->queued = false;
+
+	GError *error = dc_lock_get_error(dc);
+	if (error != NULL) {
+		player_lock(pc);
+		pc_set_error(pc, PLAYER_ERROR_DECODER, error);
+
+		song_free(pc->next_song);
+		pc->next_song = NULL;
+
+		player_unlock(pc);
+
+		return false;
+	}
+
+	if (player->song != NULL)
+		song_free(player->song);
+
+	player->song = pc->next_song;
+	player->elapsed_time = 0.0;
+
+	/* set the "starting" flag, which will be cleared by
+	   player_check_decoder_startup() */
+	player->decoder_starting = true;
+
+	player_lock(pc);
+
+	/* update player_control's song information */
+	pc->total_time = song_get_duration(pc->next_song);
+	pc->bit_rate = 0;
+	audio_format_clear(&pc->audio_format);
+
+	/* clear the queued song */
+	pc->next_song = NULL;
+
+	player_unlock(pc);
+
+	/* call syncPlaylistWithQueue() in the main thread */
+	event_pipe_emit(PIPE_EVENT_PLAYLIST);
+
+	return true;
+}
+
+/**
+ * Returns the real duration of the song, comprising the duration
+ * indicated by the decoder plugin.
+ */
+static double
+real_song_duration(const struct song *song, double decoder_duration)
+{
+	assert(song != NULL);
+
+	if (decoder_duration <= 0.0)
+		/* the decoder plugin didn't provide information; fall
+		   back to song_get_duration() */
+		return song_get_duration(song);
+
+	if (song->end_ms > 0 && song->end_ms / 1000.0 < decoder_duration)
+		return (song->end_ms - song->start_ms) / 1000.0;
+
+	return decoder_duration - song->start_ms / 1000.0;
+}
+
+/**
+ * Wrapper for audio_output_all_open().  Upon failure, it pauses the
+ * player.
+ *
+ * @return true on success
+ */
+static bool
+player_open_output(struct player *player)
+{
+	struct player_control *pc = player->pc;
+
+	assert(audio_format_defined(&player->play_audio_format));
+	assert(pc->state == PLAYER_STATE_PLAY ||
+	       pc->state == PLAYER_STATE_PAUSE);
+
+	GError *error = NULL;
+	if (audio_output_all_open(&player->play_audio_format, player_buffer,
+				  &error)) {
+		player->output_open = true;
+		player->paused = false;
+
+		player_lock(pc);
+		pc->state = PLAYER_STATE_PLAY;
+		player_unlock(pc);
+
+		return true;
+	} else {
+		g_warning("%s", error->message);
+
+		player->output_open = false;
+
+		/* pause: the user may resume playback as soon as an
+		   audio output becomes available */
+		player->paused = true;
+
+		player_lock(pc);
+		pc_set_error(pc, PLAYER_ERROR_OUTPUT, error);
+		pc->state = PLAYER_STATE_PAUSE;
+		player_unlock(pc);
+
+		return false;
+	}
+}
+
+/**
+ * The decoder has acknowledged the "START" command (see
+ * player_wait_for_decoder()).  This function checks if the decoder
+ * initialization has completed yet.
+ *
+ * The player lock is not held.
+ */
+static bool
+player_check_decoder_startup(struct player *player)
+{
+	struct player_control *pc = player->pc;
+	struct decoder_control *dc = player->dc;
+
+	assert(player->decoder_starting);
+
+	decoder_lock(dc);
+
+	GError *error = dc_get_error(dc);
+	if (error != NULL) {
+		/* the decoder failed */
+		decoder_unlock(dc);
+
+		player_lock(pc);
+		pc_set_error(pc, PLAYER_ERROR_DECODER, error);
+		player_unlock(pc);
+
+		return false;
+	} else if (!decoder_is_starting(dc)) {
+		/* the decoder is ready and ok */
+
+		decoder_unlock(dc);
+
+		if (player->output_open &&
+		    !audio_output_all_wait(pc, 1))
+			/* the output devices havn't finished playing
+			   all chunks yet - wait for that */
+			return true;
+
+		player_lock(pc);
+		pc->total_time = real_song_duration(dc->song, dc->total_time);
+		pc->audio_format = dc->in_audio_format;
+		player_unlock(pc);
+
+		player->play_audio_format = dc->out_audio_format;
+		player->decoder_starting = false;
+
+		if (!player->paused && !player_open_output(player)) {
+			char *uri = song_get_uri(dc->song);
+			g_warning("problems opening audio device "
+				  "while playing \"%s\"", uri);
+			g_free(uri);
+
+			return true;
+		}
+
+		return true;
+	} else {
+		/* the decoder is not yet ready; wait
+		   some more */
+		player_wait_decoder(pc, dc);
+		decoder_unlock(dc);
+
+		return true;
+	}
+}
+
+/**
+ * Sends a chunk of silence to the audio outputs.  This is called when
+ * there is not enough decoded data in the pipe yet, to prevent
+ * underruns in the hardware buffers.
+ *
+ * The player lock is not held.
+ */
+static bool
+player_send_silence(struct player *player)
+{
+	assert(player->output_open);
+	assert(audio_format_defined(&player->play_audio_format));
+
+	struct music_chunk *chunk = music_buffer_allocate(player_buffer);
+	if (chunk == NULL) {
+		g_warning("Failed to allocate silence buffer");
+		return false;
+	}
+
+#ifndef NDEBUG
+	chunk->audio_format = player->play_audio_format;
+#endif
+
+	size_t frame_size =
+		audio_format_frame_size(&player->play_audio_format);
+	/* this formula ensures that we don't send
+	   partial frames */
+	unsigned num_frames = sizeof(chunk->data) / frame_size;
+
+	chunk->times = -1.0; /* undefined time stamp */
+	chunk->length = num_frames * frame_size;
+	memset(chunk->data, 0, chunk->length);
+
+	GError *error = NULL;
+	if (!audio_output_all_play(chunk, &error)) {
+		g_warning("%s", error->message);
+		g_error_free(error);
+
+		music_buffer_return(player_buffer, chunk);
+		return false;
+	}
+
+	return true;
+}
+
+/**
+ * This is the handler for the #PLAYER_COMMAND_SEEK command.
+ *
+ * The player lock is not held.
+ */
+static bool player_seek_decoder(struct player *player)
+{
+	struct player_control *pc = player->pc;
+	struct song *song = pc->next_song;
+	struct decoder_control *dc = player->dc;
+
+	assert(pc->next_song != NULL);
+
+	const unsigned start_ms = song->start_ms;
+
+	if (!decoder_lock_is_current_song(dc, song)) {
+		/* the decoder is already decoding the "next" song -
+		   stop it and start the previous song again */
+
+		player_dc_stop(player);
+
+		/* clear music chunks which might still reside in the
+		   pipe */
+		music_pipe_clear(player->pipe, player_buffer);
+
+		/* re-start the decoder */
+		player_dc_start(player, player->pipe);
+		if (!player_wait_for_decoder(player)) {
+			/* decoder failure */
+			player_command_finished(pc);
+			return false;
+		}
+	} else {
+		if (!player_dc_at_current_song(player)) {
+			/* the decoder is already decoding the "next" song,
+			   but it is the same song file; exchange the pipe */
+			music_pipe_clear(player->pipe, player_buffer);
+			music_pipe_free(player->pipe);
+			player->pipe = dc->pipe;
+		}
+
+		song_free(pc->next_song);
+		pc->next_song = NULL;
+		player->queued = false;
+	}
+
+	/* wait for the decoder to complete initialization */
+
+	while (player->decoder_starting) {
+		if (!player_check_decoder_startup(player)) {
+			/* decoder failure */
+			player_command_finished(pc);
+			return false;
+		}
+	}
+
+	/* send the SEEK command */
+
+	double where = pc->seek_where;
+	if (where > pc->total_time)
+		where = pc->total_time - 0.1;
+	if (where < 0.0)
+		where = 0.0;
+
+	if (!dc_seek(dc, where + start_ms / 1000.0)) {
+		/* decoder failure */
+		player_command_finished(pc);
+		return false;
+	}
+
+	player->elapsed_time = where;
+
+	player_command_finished(pc);
+
+	player->xfade = XFADE_UNKNOWN;
+
+	/* re-fill the buffer after seeking */
+	player->buffering = true;
+
+	audio_output_all_cancel();
+
+	return true;
+}
+
+/**
+ * Player lock must be held before calling.
+ */
+static void player_process_command(struct player *player)
+{
+	struct player_control *pc = player->pc;
+	G_GNUC_UNUSED struct decoder_control *dc = player->dc;
+
+	switch (pc->command) {
+	case PLAYER_COMMAND_NONE:
+	case PLAYER_COMMAND_STOP:
+	case PLAYER_COMMAND_EXIT:
+	case PLAYER_COMMAND_CLOSE_AUDIO:
+		break;
+
+	case PLAYER_COMMAND_UPDATE_AUDIO:
+		player_unlock(pc);
+		audio_output_all_enable_disable();
+		player_lock(pc);
+		player_command_finished_locked(pc);
+		break;
+
+	case PLAYER_COMMAND_QUEUE:
+		assert(pc->next_song != NULL);
+		assert(!player->queued);
+		assert(!player_dc_at_next_song(player));
+
+		player->queued = true;
+		player_command_finished_locked(pc);
+		break;
+
+	case PLAYER_COMMAND_PAUSE:
+		player_unlock(pc);
+
+		player->paused = !player->paused;
+		if (player->paused) {
+			audio_output_all_pause();
+			player_lock(pc);
+
+			pc->state = PLAYER_STATE_PAUSE;
+		} else if (!audio_format_defined(&player->play_audio_format)) {
+			/* the decoder hasn't provided an audio format
+			   yet - don't open the audio device yet */
+			player_lock(pc);
+
+			pc->state = PLAYER_STATE_PLAY;
+		} else {
+			player_open_output(player);
+
+			player_lock(pc);
+		}
+
+		player_command_finished_locked(pc);
+		break;
+
+	case PLAYER_COMMAND_SEEK:
+		player_unlock(pc);
+		player_seek_decoder(player);
+		player_lock(pc);
+		break;
+
+	case PLAYER_COMMAND_CANCEL:
+		if (pc->next_song == NULL) {
+			/* the cancel request arrived too late, we're
+			   already playing the queued song...  stop
+			   everything now */
+			pc->command = PLAYER_COMMAND_STOP;
+			return;
+		}
+
+		if (player_dc_at_next_song(player)) {
+			/* the decoder is already decoding the song -
+			   stop it and reset the position */
+			player_unlock(pc);
+			player_dc_stop(player);
+			player_lock(pc);
+		}
+
+		song_free(pc->next_song);
+		pc->next_song = NULL;
+		player->queued = false;
+		player_command_finished_locked(pc);
+		break;
+
+	case PLAYER_COMMAND_REFRESH:
+		if (player->output_open && !player->paused) {
+			player_unlock(pc);
+			audio_output_all_check();
+			player_lock(pc);
+		}
+
+		pc->elapsed_time = audio_output_all_get_elapsed_time();
+		if (pc->elapsed_time < 0.0)
+			pc->elapsed_time = player->elapsed_time;
+
+		player_command_finished_locked(pc);
+		break;
+	}
+}
+
+static void
+update_song_tag(struct song *song, const struct tag *new_tag)
+{
+	if (song_is_file(song))
+		/* don't update tags of local files, only remote
+		   streams may change tags dynamically */
+		return;
+
+	struct tag *old_tag = song->tag;
+	song->tag = tag_dup(new_tag);
+
+	if (old_tag != NULL)
+		tag_free(old_tag);
+
+	/* the main thread will update the playlist version when he
+	   receives this event */
+	event_pipe_emit(PIPE_EVENT_TAG);
+
+	/* notify all clients that the tag of the current song has
+	   changed */
+	idle_add(IDLE_PLAYER);
+}
+
+/**
+ * Plays a #music_chunk object (after applying software volume).  If
+ * it contains a (stream) tag, copy it to the current song, so MPD's
+ * playlist reflects the new stream tag.
+ *
+ * Player lock is not held.
+ */
+static bool
+play_chunk(struct player_control *pc,
+	   struct song *song, struct music_chunk *chunk,
+	   const struct audio_format *format,
+	   GError **error_r)
+{
+	assert(music_chunk_check_format(chunk, format));
+
+	if (chunk->tag != NULL)
+		update_song_tag(song, chunk->tag);
+
+	if (chunk->length == 0) {
+		music_buffer_return(player_buffer, chunk);
+		return true;
+	}
+
+	player_lock(pc);
+	pc->bit_rate = chunk->bit_rate;
+	player_unlock(pc);
+
+	/* send the chunk to the audio outputs */
+
+	if (!audio_output_all_play(chunk, error_r))
+		return false;
+
+	pc->total_play_time += (double)chunk->length /
+		audio_format_time_to_size(format);
+	return true;
+}
+
+/**
+ * Obtains the next chunk from the music pipe, optionally applies
+ * cross-fading, and sends it to all audio outputs.
+ *
+ * @return true on success, false on error (playback will be stopped)
+ */
+static bool
+play_next_chunk(struct player *player)
+{
+	struct player_control *pc = player->pc;
+	struct decoder_control *dc = player->dc;
+
+	if (!audio_output_all_wait(pc, 64))
+		/* the output pipe is still large enough, don't send
+		   another chunk */
+		return true;
+
+	unsigned cross_fade_position;
+	struct music_chunk *chunk = NULL;
+	if (player->xfade == XFADE_ENABLED &&
+	    player_dc_at_next_song(player) &&
+	    (cross_fade_position = music_pipe_size(player->pipe))
+	    <= player->cross_fade_chunks) {
+		/* perform cross fade */
+		struct music_chunk *other_chunk =
+			music_pipe_shift(dc->pipe);
+
+		if (!player->cross_fading) {
+			/* beginning of the cross fade - adjust
+			   crossFadeChunks which might be bigger than
+			   the remaining number of chunks in the old
+			   song */
+			player->cross_fade_chunks = cross_fade_position;
+			player->cross_fading = true;
+		}
+
+		if (other_chunk != NULL) {
+			chunk = music_pipe_shift(player->pipe);
+			assert(chunk != NULL);
+			assert(chunk->other == 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;
+
+			if (isnan(pc->mixramp_delay_seconds)) {
+				chunk->mix_ratio = ((float)cross_fade_position)
+					     / player->cross_fade_chunks;
+			} else {
+				chunk->mix_ratio = nan("");
+			}
+
+			if (music_chunk_is_empty(other_chunk)) {
+				/* the "other" chunk was a music_chunk
+				   which had only a tag, but no music
+				   data - we cannot cross-fade that;
+				   but since this happens only at the
+				   beginning of the new song, we can
+				   easily recover by throwing it away
+				   now */
+				music_buffer_return(player_buffer,
+						    other_chunk);
+				other_chunk = NULL;
+			}
+
+			chunk->other = other_chunk;
+		} else {
+			/* there are not enough decoded chunks yet */
+
+			decoder_lock(dc);
+
+			if (decoder_is_idle(dc)) {
+				/* the decoder isn't running, abort
+				   cross fading */
+				decoder_unlock(dc);
+
+				player->xfade = XFADE_DISABLED;
+			} else {
+				/* wait for the decoder */
+				decoder_signal(dc);
+				player_wait_decoder(pc, dc);
+				decoder_unlock(dc);
+
+				return true;
+			}
+		}
+	}
+
+	if (chunk == NULL)
+		chunk = music_pipe_shift(player->pipe);
+
+	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 */
+
+	GError *error = NULL;
+	if (!play_chunk(player->pc, player->song, chunk,
+			&player->play_audio_format, &error)) {
+		g_warning("%s", error->message);
+
+		music_buffer_return(player_buffer, chunk);
+
+		player_lock(pc);
+
+		pc_set_error(pc, PLAYER_ERROR_OUTPUT, error);
+
+		/* pause: the user may resume playback as soon as an
+		   audio output becomes available */
+		pc->state = PLAYER_STATE_PAUSE;
+		player->paused = true;
+
+		player_unlock(pc);
+
+		return false;
+	}
+
+	/* this formula should prevent that the decoder gets woken up
+	   with each chunk; it is more efficient to make it decode a
+	   larger block at a time */
+	decoder_lock(dc);
+	if (!decoder_is_idle(dc) &&
+	    music_pipe_size(dc->pipe) <= (pc->buffered_before_play +
+					 music_buffer_size(player_buffer) * 3) / 4)
+		decoder_signal(dc);
+	decoder_unlock(dc);
+
+	return true;
+}
+
+/**
+ * This is called at the border between two songs: the audio output
+ * has consumed all chunks of the current song, and we should start
+ * sending chunks from the next one.
+ *
+ * The player lock is not held.
+ *
+ * @return true on success, false on error (playback will be stopped)
+ */
+static bool
+player_song_border(struct player *player)
+{
+	player->xfade = XFADE_UNKNOWN;
+
+	char *uri = song_get_uri(player->song);
+	g_message("played \"%s\"", uri);
+	g_free(uri);
+
+	music_pipe_free(player->pipe);
+	player->pipe = player->dc->pipe;
+
+	audio_output_all_song_border();
+
+	if (!player_wait_for_decoder(player))
+		return false;
+
+	struct player_control *const pc = player->pc;
+	player_lock(pc);
+
+	if (pc->border_pause) {
+		player->paused = true;
+		pc->state = PLAYER_STATE_PAUSE;
+	}
+
+	player_unlock(pc);
+
+	return true;
+}
+
+/*
+ * The main loop of the player thread, during playback.  This is
+ * basically a state machine, which multiplexes data between the
+ * decoder thread and the output threads.
+ */
+static void do_play(struct player_control *pc, struct decoder_control *dc)
+{
+	player player(pc, dc);
+
+	player_unlock(pc);
+
+	player.pipe = music_pipe_new();
+
+	player_dc_start(&player, player.pipe);
+	if (!player_wait_for_decoder(&player)) {
+		assert(player.song == NULL);
+
+		player_dc_stop(&player);
+		player_command_finished(pc);
+		music_pipe_free(player.pipe);
+		event_pipe_emit(PIPE_EVENT_PLAYLIST);
+		player_lock(pc);
+		return;
+	}
+
+	player_lock(pc);
+	pc->state = PLAYER_STATE_PLAY;
+
+	if (pc->command == PLAYER_COMMAND_SEEK)
+		player.elapsed_time = pc->seek_where;
+
+	player_command_finished_locked(pc);
+
+	while (true) {
+		player_process_command(&player);
+		if (pc->command == PLAYER_COMMAND_STOP ||
+		    pc->command == PLAYER_COMMAND_EXIT ||
+		    pc->command == PLAYER_COMMAND_CLOSE_AUDIO) {
+			player_unlock(pc);
+			audio_output_all_cancel();
+			break;
+		}
+
+		player_unlock(pc);
+
+		if (player.buffering) {
+			/* buffering at the start of the song - wait
+			   until the buffer is large enough, to
+			   prevent stuttering on slow machines */
+
+			if (music_pipe_size(player.pipe) < pc->buffered_before_play &&
+			    !decoder_lock_is_idle(dc)) {
+				/* not enough decoded buffer space yet */
+
+				if (!player.paused &&
+				    player.output_open &&
+				    audio_output_all_check() < 4 &&
+				    !player_send_silence(&player))
+					break;
+
+				decoder_lock(dc);
+				/* XXX race condition: check decoder again */
+				player_wait_decoder(pc, dc);
+				decoder_unlock(dc);
+				player_lock(pc);
+				continue;
+			} else {
+				/* buffering is complete */
+				player.buffering = false;
+			}
+		}
+
+		if (player.decoder_starting) {
+			/* wait until the decoder is initialized completely */
+
+			if (!player_check_decoder_startup(&player))
+				break;
+
+			player_lock(pc);
+			continue;
+		}
+
+#ifndef NDEBUG
+		/*
+		music_pipe_check_format(&play_audio_format,
+					player.next_song_chunk,
+					&dc->out_audio_format);
+		*/
+#endif
+
+		if (decoder_lock_is_idle(dc) && player.queued &&
+		    dc->pipe == player.pipe) {
+			/* the decoder has finished the current song;
+			   make it decode the next song */
+
+			assert(dc->pipe == NULL || dc->pipe == player.pipe);
+
+			player_dc_start(&player, music_pipe_new());
+		}
+
+		if (/* no cross-fading if MPD is going to pause at the
+		       end of the current song */
+		    !pc->border_pause &&
+		    player_dc_at_next_song(&player) &&
+		    player.xfade == XFADE_UNKNOWN &&
+		    !decoder_lock_is_starting(dc)) {
+			/* enable cross fading in this song?  if yes,
+			   calculate how many chunks will be required
+			   for it */
+			player.cross_fade_chunks =
+				cross_fade_calc(pc->cross_fade_seconds, dc->total_time,
+						pc->mixramp_db,
+						pc->mixramp_delay_seconds,
+						dc->replay_gain_db,
+						dc->replay_gain_prev_db,
+						dc->mixramp_start,
+						dc->mixramp_prev_end,
+						&dc->out_audio_format,
+						&player.play_audio_format,
+						music_buffer_size(player_buffer) -
+						pc->buffered_before_play);
+			if (player.cross_fade_chunks > 0) {
+				player.xfade = XFADE_ENABLED;
+				player.cross_fading = false;
+			} else
+				/* cross fading is disabled or the
+				   next song is too short */
+				player.xfade = XFADE_DISABLED;
+		}
+
+		if (player.paused) {
+			player_lock(pc);
+
+			if (pc->command == PLAYER_COMMAND_NONE)
+				player_wait(pc);
+			continue;
+		} else if (!music_pipe_empty(player.pipe)) {
+			/* at least one music chunk is ready - send it
+			   to the audio output */
+
+			play_next_chunk(&player);
+		} else if (audio_output_all_check() > 0) {
+			/* not enough data from decoder, but the
+			   output thread is still busy, so it's
+			   okay */
+
+			/* XXX synchronize in a better way */
+			g_usleep(10000);
+		} else if (player_dc_at_next_song(&player)) {
+			/* at the beginning of a new song */
+
+			if (!player_song_border(&player))
+				break;
+		} else if (decoder_lock_is_idle(dc)) {
+			/* check the size of the pipe again, because
+			   the decoder thread may have added something
+			   since we last checked */
+			if (music_pipe_empty(player.pipe)) {
+				/* wait for the hardware to finish
+				   playback */
+				audio_output_all_drain();
+				break;
+			}
+		} else if (player.output_open) {
+			/* the decoder is too busy and hasn't provided
+			   new PCM data in time: send silence (if the
+			   output pipe is empty) */
+			if (!player_send_silence(&player))
+				break;
+		}
+
+		player_lock(pc);
+	}
+
+	player_dc_stop(&player);
+
+	music_pipe_clear(player.pipe, player_buffer);
+	music_pipe_free(player.pipe);
+
+	if (player.cross_fade_tag != NULL)
+		tag_free(player.cross_fade_tag);
+
+	if (player.song != NULL)
+		song_free(player.song);
+
+	player_lock(pc);
+
+	if (player.queued) {
+		assert(pc->next_song != NULL);
+		song_free(pc->next_song);
+		pc->next_song = NULL;
+	}
+
+	pc->state = PLAYER_STATE_STOP;
+
+	player_unlock(pc);
+
+	event_pipe_emit(PIPE_EVENT_PLAYLIST);
+
+	player_lock(pc);
+}
+
+static gpointer
+player_task(gpointer arg)
+{
+	struct player_control *pc = (struct player_control *)arg;
+
+	struct decoder_control *dc = dc_new(pc->cond);
+	decoder_thread_start(dc);
+
+	player_buffer = music_buffer_new(pc->buffer_chunks);
+
+	player_lock(pc);
+
+	while (1) {
+		switch (pc->command) {
+		case PLAYER_COMMAND_SEEK:
+		case PLAYER_COMMAND_QUEUE:
+			assert(pc->next_song != NULL);
+
+			do_play(pc, dc);
+			break;
+
+		case PLAYER_COMMAND_STOP:
+			player_unlock(pc);
+			audio_output_all_cancel();
+			player_lock(pc);
+
+			/* fall through */
+
+		case PLAYER_COMMAND_PAUSE:
+			if (pc->next_song != NULL) {
+				song_free(pc->next_song);
+				pc->next_song = NULL;
+			}
+
+			player_command_finished_locked(pc);
+			break;
+
+		case PLAYER_COMMAND_CLOSE_AUDIO:
+			player_unlock(pc);
+
+			audio_output_all_release();
+
+			player_lock(pc);
+			player_command_finished_locked(pc);
+
+#ifndef NDEBUG
+			/* in the DEBUG build, check for leaked
+			   music_chunk objects by freeing the
+			   music_buffer */
+			music_buffer_free(player_buffer);
+			player_buffer = music_buffer_new(pc->buffer_chunks);
+#endif
+
+			break;
+
+		case PLAYER_COMMAND_UPDATE_AUDIO:
+			player_unlock(pc);
+			audio_output_all_enable_disable();
+			player_lock(pc);
+			player_command_finished_locked(pc);
+			break;
+
+		case PLAYER_COMMAND_EXIT:
+			player_unlock(pc);
+
+			dc_quit(dc);
+			dc_free(dc);
+			audio_output_all_close();
+			music_buffer_free(player_buffer);
+
+			player_command_finished(pc);
+			return NULL;
+
+		case PLAYER_COMMAND_CANCEL:
+			if (pc->next_song != NULL) {
+				song_free(pc->next_song);
+				pc->next_song = NULL;
+			}
+
+			player_command_finished_locked(pc);
+			break;
+
+		case PLAYER_COMMAND_REFRESH:
+			/* no-op when not playing */
+			player_command_finished_locked(pc);
+			break;
+
+		case PLAYER_COMMAND_NONE:
+			player_wait(pc);
+			break;
+		}
+	}
+}
+
+void
+player_create(struct player_control *pc)
+{
+	assert(pc->thread == NULL);
+
+	GError *e = NULL;
+	pc->thread = g_thread_create(player_task, pc, true, &e);
+	if (pc->thread == NULL)
+		MPD_ERROR("Failed to spawn player task: %s", e->message);
+}