decoder_control: removed the global variable "dc"

Allocate a decoder_control object where needed, and pass it around.
This will allow more than one decoder thread one day.

7 files changed, 284 insertions, 240 deletions

diff --git a/src/decoder_api.c b/src/decoder_api.c
index 070151a67..f1ce0f5f7 100644
--- a/src/decoder_api.c
+++ b/src/decoder_api.c
@@ -37,12 +37,15 @@
 #undef G_LOG_DOMAIN
 #define G_LOG_DOMAIN "decoder"
 
-void decoder_initialized(G_GNUC_UNUSED struct decoder * decoder,
-			 const struct audio_format *audio_format,
-			 bool seekable, float total_time)
+void
+decoder_initialized(struct decoder *decoder,
+		    const struct audio_format *audio_format,
+		    bool seekable, float total_time)
 {
-	assert(dc.state == DECODE_STATE_START);
-	assert(dc.pipe != NULL);
+	struct decoder_control *dc = decoder->dc;
+
+	assert(dc->state == DECODE_STATE_START);
+	assert(dc->pipe != NULL);
 	assert(decoder != NULL);
 	assert(decoder->stream_tag == NULL);
 	assert(decoder->decoder_tag == NULL);
@@ -51,86 +54,98 @@ void decoder_initialized(G_GNUC_UNUSED struct decoder * decoder,
 	assert(audio_format_defined(audio_format));
 	assert(audio_format_valid(audio_format));
 
-	dc.in_audio_format = *audio_format;
-	getOutputAudioFormat(audio_format, &dc.out_audio_format);
+	dc->in_audio_format = *audio_format;
+	getOutputAudioFormat(audio_format, &dc->out_audio_format);
 
-	dc.seekable = seekable;
-	dc.total_time = total_time;
+	dc->seekable = seekable;
+	dc->total_time = total_time;
 
-	decoder_lock();
-	dc.state = DECODE_STATE_DECODE;
-	decoder_unlock();
+	decoder_lock(dc);
+	dc->state = DECODE_STATE_DECODE;
+	decoder_unlock(dc);
 
 	player_lock_signal();
 
 	g_debug("audio_format=%u:%u:%u, seekable=%s",
-		dc.in_audio_format.sample_rate, dc.in_audio_format.bits,
-		dc.in_audio_format.channels,
+		dc->in_audio_format.sample_rate,
+		dc->in_audio_format.bits,
+		dc->in_audio_format.channels,
 		seekable ? "true" : "false");
 
-	if (!audio_format_equals(&dc.in_audio_format, &dc.out_audio_format))
+	if (!audio_format_equals(&dc->in_audio_format,
+				 &dc->out_audio_format))
 		g_debug("converting to %u:%u:%u",
-			dc.out_audio_format.sample_rate,
-			dc.out_audio_format.bits,
-			dc.out_audio_format.channels);
+			dc->out_audio_format.sample_rate,
+			dc->out_audio_format.bits,
+			dc->out_audio_format.channels);
 }
 
 char *decoder_get_uri(G_GNUC_UNUSED struct decoder *decoder)
 {
-	assert(dc.pipe != NULL);
+	const struct decoder_control *dc = decoder->dc;
+
+	assert(dc->pipe != NULL);
 
-	return song_get_uri(dc.current_song);
+	return song_get_uri(dc->current_song);
 }
 
 enum decoder_command decoder_get_command(G_GNUC_UNUSED struct decoder * decoder)
 {
-	assert(dc.pipe != NULL);
+	const struct decoder_control *dc = decoder->dc;
+
+	assert(dc->pipe != NULL);
 
-	return dc.command;
+	return dc->command;
 }
 
 void decoder_command_finished(G_GNUC_UNUSED struct decoder * decoder)
 {
-	decoder_lock();
+	struct decoder_control *dc = decoder->dc;
 
-	assert(dc.command != DECODE_COMMAND_NONE);
-	assert(dc.command != DECODE_COMMAND_SEEK ||
-	       dc.seek_error || decoder->seeking);
-	assert(dc.pipe != NULL);
+	decoder_lock(dc);
 
-	if (dc.command == DECODE_COMMAND_SEEK) {
+	assert(dc->command != DECODE_COMMAND_NONE);
+	assert(dc->command != DECODE_COMMAND_SEEK ||
+	       dc->seek_error || decoder->seeking);
+	assert(dc->pipe != NULL);
+
+	if (dc->command == DECODE_COMMAND_SEEK) {
 		/* delete frames from the old song position */
 
 		if (decoder->chunk != NULL) {
-			music_buffer_return(dc.buffer, decoder->chunk);
+			music_buffer_return(dc->buffer, decoder->chunk);
 			decoder->chunk = NULL;
 		}
 
-		music_pipe_clear(dc.pipe, dc.buffer);
+		music_pipe_clear(dc->pipe, dc->buffer);
 	}
 
-	dc.command = DECODE_COMMAND_NONE;
-	decoder_unlock();
+	dc->command = DECODE_COMMAND_NONE;
+	decoder_unlock(dc);
 
 	player_lock_signal();
 }
 
 double decoder_seek_where(G_GNUC_UNUSED struct decoder * decoder)
 {
-	assert(dc.command == DECODE_COMMAND_SEEK);
-	assert(dc.pipe != NULL);
+	const struct decoder_control *dc = decoder->dc;
+
+	assert(dc->command == DECODE_COMMAND_SEEK);
+	assert(dc->pipe != NULL);
 
 	decoder->seeking = true;
 
-	return dc.seek_where;
+	return dc->seek_where;
 }
 
 void decoder_seek_error(struct decoder * decoder)
 {
-	assert(dc.command == DECODE_COMMAND_SEEK);
-	assert(dc.pipe != NULL);
+	struct decoder_control *dc = decoder->dc;
+
+	assert(dc->command == DECODE_COMMAND_SEEK);
+	assert(dc->pipe != NULL);
 
-	dc.seek_error = true;
+	dc->seek_error = true;
 	decoder_command_finished(decoder);
 }
 
@@ -138,11 +153,12 @@ size_t decoder_read(struct decoder *decoder,
 		    struct input_stream *is,
 		    void *buffer, size_t length)
 {
+	const struct decoder_control *dc = decoder->dc;
 	size_t nbytes;
 
 	assert(decoder == NULL ||
-	       dc.state == DECODE_STATE_START ||
-	       dc.state == DECODE_STATE_DECODE);
+	       dc->state == DECODE_STATE_START ||
+	       dc->state == DECODE_STATE_DECODE);
 	assert(is != NULL);
 	assert(buffer != NULL);
 
@@ -155,9 +171,9 @@ size_t decoder_read(struct decoder *decoder,
 		    /* ignore the SEEK command during initialization,
 		       the plugin should handle that after it has
 		       initialized successfully */
-		    (dc.command != DECODE_COMMAND_SEEK ||
-		     (dc.state != DECODE_STATE_START && !decoder->seeking)) &&
-		    dc.command != DECODE_COMMAND_NONE)
+		    (dc->command != DECODE_COMMAND_SEEK ||
+		     (dc->state != DECODE_STATE_START && !decoder->seeking)) &&
+		    dc->command != DECODE_COMMAND_NONE)
 			return 0;
 
 		nbytes = input_stream_read(is, buffer, length);
@@ -191,8 +207,8 @@ do_send_tag(struct decoder *decoder, struct input_stream *is,
 
 	chunk = decoder_get_chunk(decoder, is);
 	if (chunk == NULL) {
-		assert(dc.command != DECODE_COMMAND_NONE);
-		return dc.command;
+		assert(decoder->dc->command != DECODE_COMMAND_NONE);
+		return decoder->dc->command;
 	}
 
 	chunk->tag = tag_dup(tag);
@@ -231,17 +247,18 @@ decoder_data(struct decoder *decoder,
 	     float data_time, uint16_t bitRate,
 	     struct replay_gain_info *replay_gain_info)
 {
+	struct decoder_control *dc = decoder->dc;
 	const char *data = _data;
 	GError *error = NULL;
 	enum decoder_command cmd;
 
-	assert(dc.state == DECODE_STATE_DECODE);
-	assert(dc.pipe != NULL);
-	assert(length % audio_format_frame_size(&dc.in_audio_format) == 0);
+	assert(dc->state == DECODE_STATE_DECODE);
+	assert(dc->pipe != NULL);
+	assert(length % audio_format_frame_size(&dc->in_audio_format) == 0);
 
-	decoder_lock();
-	cmd = dc.command;
-	decoder_unlock();
+	decoder_lock(dc);
+	cmd = dc->command;
+	decoder_unlock(dc);
 
 	if (cmd == DECODE_COMMAND_STOP || cmd == DECODE_COMMAND_SEEK ||
 	    length == 0)
@@ -266,10 +283,10 @@ decoder_data(struct decoder *decoder,
 			return cmd;
 	}
 
-	if (!audio_format_equals(&dc.in_audio_format, &dc.out_audio_format)) {
+	if (!audio_format_equals(&dc->in_audio_format, &dc->out_audio_format)) {
 		data = pcm_convert(&decoder->conv_state,
-				   &dc.in_audio_format, data, length,
-				   &dc.out_audio_format, &length,
+				   &dc->in_audio_format, data, length,
+				   &dc->out_audio_format, &length,
 				   &error);
 		if (data == NULL) {
 			/* the PCM conversion has failed - stop
@@ -288,11 +305,11 @@ decoder_data(struct decoder *decoder,
 
 		chunk = decoder_get_chunk(decoder, is);
 		if (chunk == NULL) {
-			assert(dc.command != DECODE_COMMAND_NONE);
-			return dc.command;
+			assert(dc->command != DECODE_COMMAND_NONE);
+			return dc->command;
 		}
 
-		dest = music_chunk_write(chunk, &dc.out_audio_format,
+		dest = music_chunk_write(chunk, &dc->out_audio_format,
 					 data_time, bitRate, &nbytes);
 		if (dest == NULL) {
 			/* the chunk is full, flush it */
@@ -314,13 +331,13 @@ decoder_data(struct decoder *decoder,
 
 		if (replay_gain_mode != REPLAY_GAIN_OFF)
 			replay_gain_apply(replay_gain_info, dest, nbytes,
-					  &dc.out_audio_format);
+					  &dc->out_audio_format);
 		else if (normalizationEnabled)
-			normalizeData(dest, nbytes, &dc.out_audio_format);
+			normalizeData(dest, nbytes, &dc->out_audio_format);
 
 		/* expand the music pipe chunk */
 
-		full = music_chunk_expand(chunk, &dc.out_audio_format, nbytes);
+		full = music_chunk_expand(chunk, &dc->out_audio_format, nbytes);
 		if (full) {
 			/* the chunk is full, flush it */
 			decoder_flush_chunk(decoder);
@@ -338,10 +355,11 @@ enum decoder_command
 decoder_tag(G_GNUC_UNUSED struct decoder *decoder, struct input_stream *is,
 	    const struct tag *tag)
 {
+	const struct decoder_control *dc = decoder->dc;
 	enum decoder_command cmd;
 
-	assert(dc.state == DECODE_STATE_DECODE);
-	assert(dc.pipe != NULL);
+	assert(dc->state == DECODE_STATE_DECODE);
+	assert(dc->pipe != NULL);
 	assert(tag != NULL);
 
 	/* save the tag */
diff --git a/src/decoder_control.c b/src/decoder_control.c
index d7f5808fc..10f576c5c 100644
--- a/src/decoder_control.c
+++ b/src/decoder_control.c
@@ -22,131 +22,134 @@
 
 #include <assert.h>
 
-struct decoder_control dc;
-
-void dc_init(void)
+void
+dc_init(struct decoder_control *dc)
 {
-	dc.mutex = g_mutex_new();
-	dc.cond = g_cond_new();
+	dc->thread = NULL;
+
+	dc->mutex = g_mutex_new();
+	dc->cond = g_cond_new();
 
-	dc.state = DECODE_STATE_STOP;
-	dc.command = DECODE_COMMAND_NONE;
+	dc->state = DECODE_STATE_STOP;
+	dc->command = DECODE_COMMAND_NONE;
 }
 
-void dc_deinit(void)
+void
+dc_deinit(struct decoder_control *dc)
 {
-	g_cond_free(dc.cond);
-	g_mutex_free(dc.mutex);
+	g_cond_free(dc->cond);
+	g_mutex_free(dc->mutex);
 }
 
 static void
-dc_command_wait_locked(void)
+dc_command_wait_locked(struct decoder_control *dc)
 {
-	while (dc.command != DECODE_COMMAND_NONE) {
-		decoder_signal();
-		player_wait_decoder();
+	while (dc->command != DECODE_COMMAND_NONE) {
+		decoder_signal(dc);
+		player_wait_decoder(dc);
 	}
 }
 
 void
-dc_command_wait(void)
+dc_command_wait(struct decoder_control *dc)
 {
-	decoder_lock();
-	dc_command_wait_locked();
-	decoder_unlock();
+	decoder_lock(dc);
+	dc_command_wait_locked(dc);
+	decoder_unlock(dc);
 }
 
 static void
-dc_command_locked(enum decoder_command cmd)
+dc_command_locked(struct decoder_control *dc, enum decoder_command cmd)
 {
-	dc.command = cmd;
-	dc_command_wait_locked();
+	dc->command = cmd;
+	dc_command_wait_locked(dc);
 }
 
 static void
-dc_command(enum decoder_command cmd)
+dc_command(struct decoder_control *dc, enum decoder_command cmd)
 {
-	decoder_lock();
-	dc_command_locked(cmd);
-	decoder_unlock();
+	decoder_lock(dc);
+	dc_command_locked(dc, cmd);
+	decoder_unlock(dc);
 }
 
-static void dc_command_async(enum decoder_command cmd)
+static void
+dc_command_async(struct decoder_control *dc, enum decoder_command cmd)
 {
-	decoder_lock();
+	decoder_lock(dc);
 
-	dc.command = cmd;
-	decoder_signal();
+	dc->command = cmd;
+	decoder_signal(dc);
 
-	decoder_unlock();
+	decoder_unlock(dc);
 }
 
 void
-dc_start(struct song *song)
+dc_start(struct decoder_control *dc, struct song *song)
 {
-	assert(dc.pipe != NULL);
+	assert(dc->pipe != NULL);
 	assert(song != NULL);
 
-	dc.next_song = song;
-	dc_command(DECODE_COMMAND_START);
+	dc->next_song = song;
+	dc_command(dc, DECODE_COMMAND_START);
 }
 
 void
-dc_start_async(struct song *song)
+dc_start_async(struct decoder_control *dc, struct song *song)
 {
-	assert(dc.pipe != NULL);
+	assert(dc->pipe != NULL);
 	assert(song != NULL);
 
-	dc.next_song = song;
-	dc_command_async(DECODE_COMMAND_START);
+	dc->next_song = song;
+	dc_command_async(dc, DECODE_COMMAND_START);
 }
 
 void
-dc_stop(void)
+dc_stop(struct decoder_control *dc)
 {
-	decoder_lock();
+	decoder_lock(dc);
 
-	if (dc.command != DECODE_COMMAND_NONE)
+	if (dc->command != DECODE_COMMAND_NONE)
 		/* Attempt to cancel the current command.  If it's too
 		   late and the decoder thread is already executing
 		   the old command, we'll call STOP again in this
 		   function (see below). */
-		dc_command_locked(DECODE_COMMAND_STOP);
+		dc_command_locked(dc, DECODE_COMMAND_STOP);
 
-	if (dc.state != DECODE_STATE_STOP && dc.state != DECODE_STATE_ERROR)
-		dc_command_locked(DECODE_COMMAND_STOP);
+	if (dc->state != DECODE_STATE_STOP && dc->state != DECODE_STATE_ERROR)
+		dc_command_locked(dc, DECODE_COMMAND_STOP);
 
-	decoder_unlock();
+	decoder_unlock(dc);
 }
 
 bool
-dc_seek(double where)
+dc_seek(struct decoder_control *dc, double where)
 {
-	assert(dc.state != DECODE_STATE_START);
+	assert(dc->state != DECODE_STATE_START);
 	assert(where >= 0.0);
 
-	if (dc.state == DECODE_STATE_STOP ||
-	    dc.state == DECODE_STATE_ERROR || !dc.seekable)
+	if (dc->state == DECODE_STATE_STOP ||
+	    dc->state == DECODE_STATE_ERROR || !dc->seekable)
 		return false;
 
-	dc.seek_where = where;
-	dc.seek_error = false;
-	dc_command(DECODE_COMMAND_SEEK);
+	dc->seek_where = where;
+	dc->seek_error = false;
+	dc_command(dc, DECODE_COMMAND_SEEK);
 
-	if (dc.seek_error)
+	if (dc->seek_error)
 		return false;
 
 	return true;
 }
 
 void
-dc_quit(void)
+dc_quit(struct decoder_control *dc)
 {
-	assert(dc.thread != NULL);
+	assert(dc->thread != NULL);
 
-	dc.quit = true;
-	dc_command_async(DECODE_COMMAND_STOP);
+	dc->quit = true;
+	dc_command_async(dc, DECODE_COMMAND_STOP);
 
-	g_thread_join(dc.thread);
-	dc.thread = NULL;
+	g_thread_join(dc->thread);
+	dc->thread = NULL;
 }
diff --git a/src/decoder_control.h b/src/decoder_control.h
index cab6c69c7..d03c7a805 100644
--- a/src/decoder_control.h
+++ b/src/decoder_control.h
@@ -83,28 +83,28 @@ struct decoder_control {
 	struct music_pipe *pipe;
 };
 
-extern struct decoder_control dc;
-
-void dc_init(void);
+void
+dc_init(struct decoder_control *dc);
 
-void dc_deinit(void);
+void
+dc_deinit(struct decoder_control *dc);
 
 /**
  * Locks the #decoder_control object.
  */
 static inline void
-decoder_lock(void)
+decoder_lock(struct decoder_control *dc)
 {
-	g_mutex_lock(dc.mutex);
+	g_mutex_lock(dc->mutex);
 }
 
 /**
  * Unlocks the #decoder_control object.
  */
 static inline void
-decoder_unlock(void)
+decoder_unlock(struct decoder_control *dc)
 {
-	g_mutex_unlock(dc.mutex);
+	g_mutex_unlock(dc->mutex);
 }
 
 /**
@@ -113,9 +113,9 @@ decoder_unlock(void)
  * prior to calling this function.
  */
 static inline void
-decoder_wait(void)
+decoder_wait(struct decoder_control *dc)
 {
-	g_cond_wait(dc.cond, dc.mutex);
+	g_cond_wait(dc->cond, dc->mutex);
 }
 
 /**
@@ -124,75 +124,81 @@ decoder_wait(void)
  * this function.
  */
 static inline void
-decoder_signal(void)
+decoder_signal(struct decoder_control *dc)
 {
-	g_cond_signal(dc.cond);
+	g_cond_signal(dc->cond);
 }
 
-static inline bool decoder_is_idle(void)
+static inline bool
+decoder_is_idle(const struct decoder_control *dc)
 {
-	return (dc.state == DECODE_STATE_STOP ||
-		dc.state == DECODE_STATE_ERROR) &&
-		dc.command != DECODE_COMMAND_START;
+	return (dc->state == DECODE_STATE_STOP ||
+		dc->state == DECODE_STATE_ERROR) &&
+		dc->command != DECODE_COMMAND_START;
 }
 
-static inline bool decoder_is_starting(void)
+static inline bool
+decoder_is_starting(const struct decoder_control *dc)
 {
-	return dc.command == DECODE_COMMAND_START ||
-		dc.state == DECODE_STATE_START;
+	return dc->command == DECODE_COMMAND_START ||
+		dc->state == DECODE_STATE_START;
 }
 
-static inline bool decoder_has_failed(void)
+static inline bool
+decoder_has_failed(const struct decoder_control *dc)
 {
-	assert(dc.command == DECODE_COMMAND_NONE);
+	assert(dc->command == DECODE_COMMAND_NONE);
 
-	return dc.state == DECODE_STATE_ERROR;
+	return dc->state == DECODE_STATE_ERROR;
 }
 
-static inline bool decoder_lock_is_idle(void)
+static inline bool
+decoder_lock_is_idle(struct decoder_control *dc)
 {
 	bool ret;
 
-	decoder_lock();
-	ret = decoder_is_idle();
-	decoder_unlock();
+	decoder_lock(dc);
+	ret = decoder_is_idle(dc);
+	decoder_unlock(dc);
 
 	return ret;
 }
 
-static inline bool decoder_lock_is_starting(void)
+static inline bool
+decoder_lock_is_starting(struct decoder_control *dc)
 {
 	bool ret;
 
-	decoder_lock();
-	ret = decoder_is_starting();
-	decoder_unlock();
+	decoder_lock(dc);
+	ret = decoder_is_starting(dc);
+	decoder_unlock(dc);
 
 	return ret;
 }
 
-static inline bool decoder_lock_has_failed(void)
+static inline bool
+decoder_lock_has_failed(struct decoder_control *dc)
 {
 	bool ret;
 
-	decoder_lock();
-	ret = decoder_has_failed();
-	decoder_unlock();
+	decoder_lock(dc);
+	ret = decoder_has_failed(dc);
+	decoder_unlock(dc);
 
 	return ret;
 }
 
-static inline struct song *
-decoder_current_song(void)
+static inline const struct song *
+decoder_current_song(const struct decoder_control *dc)
 {
-	switch (dc.state) {
+	switch (dc->state) {
 	case DECODE_STATE_STOP:
 	case DECODE_STATE_ERROR:
 		return NULL;
 
 	case DECODE_STATE_START:
 	case DECODE_STATE_DECODE:
-		return dc.current_song;
+		return dc->current_song;
 	}
 
 	assert(false);
@@ -200,21 +206,21 @@ decoder_current_song(void)
 }
 
 void
-dc_command_wait(void);
+dc_command_wait(struct decoder_control *dc);
 
 void
-dc_start(struct song *song);
+dc_start(struct decoder_control *dc, struct song *song);
 
 void
-dc_start_async(struct song *song);
+dc_start_async(struct decoder_control *dc, struct song *song);
 
 void
-dc_stop(void);
+dc_stop(struct decoder_control *dc);
 
 bool
-dc_seek(double where);
+dc_seek(struct decoder_control *dc, double where);
 
 void
-dc_quit(void);
+dc_quit(struct decoder_control *dc);
 
 #endif
diff --git a/src/decoder_internal.c b/src/decoder_internal.c
index db90333b4..d40ef89d7 100644
--- a/src/decoder_internal.c
+++ b/src/decoder_internal.c
@@ -34,13 +34,13 @@
  * potentially blocking operation.
  */
 static int
-decoder_input_buffer(struct input_stream *is)
+decoder_input_buffer(struct decoder_control *dc, struct input_stream *is)
 {
 	int ret;
 
-	decoder_unlock();
+	decoder_unlock(dc);
 	ret = input_stream_buffer(is) > 0;
-	decoder_lock();
+	decoder_lock(dc);
 
 	return ret;
 }
@@ -50,17 +50,17 @@ decoder_input_buffer(struct input_stream *is)
  * one.
  */
 static enum decoder_command
-need_chunks(struct input_stream *is, bool do_wait)
+need_chunks(struct decoder_control *dc, struct input_stream *is, bool do_wait)
 {
-	if (dc.command == DECODE_COMMAND_STOP ||
-	    dc.command == DECODE_COMMAND_SEEK)
-		return dc.command;
+	if (dc->command == DECODE_COMMAND_STOP ||
+	    dc->command == DECODE_COMMAND_SEEK)
+		return dc->command;
 
-	if ((is == NULL || decoder_input_buffer(is) <= 0) && do_wait) {
-		decoder_wait();
+	if ((is == NULL || decoder_input_buffer(dc, is) <= 0) && do_wait) {
+		decoder_wait(dc);
 		player_signal();
 
-		return dc.command;
+		return dc->command;
 	}
 
 	return DECODE_COMMAND_NONE;
@@ -69,6 +69,7 @@ need_chunks(struct input_stream *is, bool do_wait)
 struct music_chunk *
 decoder_get_chunk(struct decoder *decoder, struct input_stream *is)
 {
+	struct decoder_control *dc = decoder->dc;
 	enum decoder_command cmd;
 
 	assert(decoder != NULL);
@@ -77,13 +78,13 @@ decoder_get_chunk(struct decoder *decoder, struct input_stream *is)
 		return decoder->chunk;
 
 	do {
-		decoder->chunk = music_buffer_allocate(dc.buffer);
+		decoder->chunk = music_buffer_allocate(dc->buffer);
 		if (decoder->chunk != NULL)
 			return decoder->chunk;
 
-		decoder_lock();
-		cmd = need_chunks(is, true);
-		decoder_unlock();
+		decoder_lock(dc);
+		cmd = need_chunks(dc, is, true);
+		decoder_unlock(dc);
 	} while (cmd == DECODE_COMMAND_NONE);
 
 	return NULL;
@@ -92,13 +93,15 @@ decoder_get_chunk(struct decoder *decoder, struct input_stream *is)
 void
 decoder_flush_chunk(struct decoder *decoder)
 {
+	struct decoder_control *dc = decoder->dc;
+
 	assert(decoder != NULL);
 	assert(decoder->chunk != NULL);
 
 	if (music_chunk_is_empty(decoder->chunk))
-		music_buffer_return(dc.buffer, decoder->chunk);
+		music_buffer_return(dc->buffer, decoder->chunk);
 	else
-		music_pipe_push(dc.pipe, decoder->chunk);
+		music_pipe_push(dc->pipe, decoder->chunk);
 
 	decoder->chunk = NULL;
 }
diff --git a/src/decoder_internal.h b/src/decoder_internal.h
index cf54dbf6d..9d422d253 100644
--- a/src/decoder_internal.h
+++ b/src/decoder_internal.h
@@ -26,6 +26,8 @@
 struct input_stream;
 
 struct decoder {
+	struct decoder_control *dc;
+
 	struct pcm_convert_state conv_state;
 
 	bool seeking;
diff --git a/src/decoder_thread.c b/src/decoder_thread.c
index 712e4d20c..7308795c3 100644
--- a/src/decoder_thread.c
+++ b/src/decoder_thread.c
@@ -47,21 +47,21 @@ decoder_stream_decode(const struct decoder_plugin *plugin,
 	assert(decoder->decoder_tag == NULL);
 	assert(input_stream != NULL);
 	assert(input_stream->ready);
-	assert(dc.state == DECODE_STATE_START);
+	assert(decoder->dc->state == DECODE_STATE_START);
 
-	decoder_unlock();
+	decoder_unlock(decoder->dc);
 
 	/* rewind the stream, so each plugin gets a fresh start */
 	input_stream_seek(input_stream, 0, SEEK_SET);
 
 	decoder_plugin_stream_decode(plugin, decoder, input_stream);
 
-	decoder_lock();
+	decoder_lock(decoder->dc);
 
-	assert(dc.state == DECODE_STATE_START ||
-	       dc.state == DECODE_STATE_DECODE);
+	assert(decoder->dc->state == DECODE_STATE_START ||
+	       decoder->dc->state == DECODE_STATE_DECODE);
 
-	return dc.state != DECODE_STATE_START;
+	return decoder->dc->state != DECODE_STATE_START;
 }
 
 static bool
@@ -75,30 +75,34 @@ decoder_file_decode(const struct decoder_plugin *plugin,
 	assert(decoder->decoder_tag == NULL);
 	assert(path != NULL);
 	assert(g_path_is_absolute(path));
-	assert(dc.state == DECODE_STATE_START);
+	assert(decoder->dc->state == DECODE_STATE_START);
 
-	decoder_unlock();
+	decoder_unlock(decoder->dc);
 
 	decoder_plugin_file_decode(plugin, decoder, path);
 
-	decoder_lock();
+	decoder_lock(decoder->dc);
 
-	assert(dc.state == DECODE_STATE_START ||
-	       dc.state == DECODE_STATE_DECODE);
+	assert(decoder->dc->state == DECODE_STATE_START ||
+	       decoder->dc->state == DECODE_STATE_DECODE);
 
-	return dc.state != DECODE_STATE_START;
+	return decoder->dc->state != DECODE_STATE_START;
 }
 
-static void decoder_run_song(const struct song *song, const char *uri)
+static void
+decoder_run_song(struct decoder_control *dc,
+		 const struct song *song, const char *uri)
 {
-	struct decoder decoder;
+	struct decoder decoder = {
+		.dc = dc,
+	};
 	int ret;
 	bool close_instream = true;
 	struct input_stream input_stream;
 	const struct decoder_plugin *plugin;
 
 	if (!input_stream_open(&input_stream, uri)) {
-		dc.state = DECODE_STATE_ERROR;
+		dc->state = DECODE_STATE_ERROR;
 		return;
 	}
 
@@ -109,8 +113,8 @@ static void decoder_run_song(const struct song *song, const char *uri)
 	decoder.decoder_tag = NULL;
 	decoder.chunk = NULL;
 
-	dc.state = DECODE_STATE_START;
-	dc.command = DECODE_COMMAND_NONE;
+	dc->state = DECODE_STATE_START;
+	dc->command = DECODE_COMMAND_NONE;
 
 	player_signal();
 
@@ -118,32 +122,32 @@ static void decoder_run_song(const struct song *song, const char *uri)
 	   will be available then */
 
 	while (!input_stream.ready) {
-		if (dc.command == DECODE_COMMAND_STOP) {
-			decoder_unlock();
+		if (dc->command == DECODE_COMMAND_STOP) {
+			decoder_unlock(dc);
 			input_stream_close(&input_stream);
-			decoder_lock();
-			dc.state = DECODE_STATE_STOP;
+			decoder_lock(dc);
+			dc->state = DECODE_STATE_STOP;
 			return;
 		}
 
-		decoder_unlock();
+		decoder_unlock(dc);
 		ret = input_stream_buffer(&input_stream);
 		if (ret < 0) {
 			input_stream_close(&input_stream);
-			decoder_lock();
-			dc.state = DECODE_STATE_ERROR;
+			decoder_lock(dc);
+			dc->state = DECODE_STATE_ERROR;
 			return;
 		}
 
-		decoder_lock();
+		decoder_lock(dc);
 	}
 
-	if (dc.command == DECODE_COMMAND_STOP) {
-		decoder_unlock();
+	if (dc->command == DECODE_COMMAND_STOP) {
+		decoder_unlock(dc);
 		input_stream_close(&input_stream);
-		decoder_lock();
+		decoder_lock(dc);
 
-		dc.state = DECODE_STATE_STOP;
+		dc->state = DECODE_STATE_STOP;
 		return;
 	}
 
@@ -162,7 +166,7 @@ static void decoder_run_song(const struct song *song, const char *uri)
 			if (ret)
 				break;
 
-			assert(dc.state == DECODE_STATE_START);
+			assert(dc->state == DECODE_STATE_START);
 		}
 
 		/* if that fails, try suffix matching the URL: */
@@ -177,7 +181,7 @@ static void decoder_run_song(const struct song *song, const char *uri)
 				if (ret)
 					break;
 
-				assert(dc.state == DECODE_STATE_START);
+				assert(dc->state == DECODE_STATE_START);
 			}
 		}
 		/* fallback to mp3: */
@@ -196,9 +200,9 @@ static void decoder_run_song(const struct song *song, const char *uri)
 		const char *s = uri_get_suffix(uri);
 		while ((plugin = decoder_plugin_from_suffix(s, next++))) {
 			if (plugin->file_decode != NULL) {
-				decoder_unlock();
+				decoder_unlock(dc);
 				input_stream_close(&input_stream);
-				decoder_lock();
+				decoder_lock(dc);
 
 				close_instream = false;
 				ret = decoder_file_decode(plugin,
@@ -213,9 +217,9 @@ static void decoder_run_song(const struct song *song, const char *uri)
 					   reopen it */
 					bool success;
 
-					decoder_unlock();
+					decoder_unlock(dc);
 					success = input_stream_open(&input_stream, uri);
-					decoder_lock();
+					decoder_lock(dc);
 
 					if (success)
 						close_instream = true;
@@ -231,7 +235,7 @@ static void decoder_run_song(const struct song *song, const char *uri)
 		}
 	}
 
-	decoder_unlock();
+	decoder_unlock(dc);
 
 	pcm_convert_deinit(&decoder.conv_state);
 
@@ -251,14 +255,15 @@ static void decoder_run_song(const struct song *song, const char *uri)
 	if (decoder.decoder_tag != NULL)
 		tag_free(decoder.decoder_tag);
 
-	decoder_lock();
+	decoder_lock(dc);
 
-	dc.state = ret ? DECODE_STATE_STOP : DECODE_STATE_ERROR;
+	dc->state = ret ? DECODE_STATE_STOP : DECODE_STATE_ERROR;
 }
 
-static void decoder_run(void)
+static void
+decoder_run(struct decoder_control *dc)
 {
-	struct song *song = dc.next_song;
+	struct song *song = dc->next_song;
 	char *uri;
 
 	if (song_is_file(song))
@@ -267,58 +272,62 @@ static void decoder_run(void)
 		uri = song_get_uri(song);
 
 	if (uri == NULL) {
-		dc.state = DECODE_STATE_ERROR;
+		dc->state = DECODE_STATE_ERROR;
 		return;
 	}
 
-	dc.current_song = dc.next_song; /* NEED LOCK */
-	decoder_run_song(song, uri);
+	dc->current_song = dc->next_song; /* NEED LOCK */
+	decoder_run_song(dc, song, uri);
 	g_free(uri);
 
 }
 
-static gpointer decoder_task(G_GNUC_UNUSED gpointer arg)
+static gpointer
+decoder_task(gpointer arg)
 {
-	decoder_lock();
+	struct decoder_control *dc = arg;
+
+	decoder_lock(dc);
 
 	do {
-		assert(dc.state == DECODE_STATE_STOP ||
-		       dc.state == DECODE_STATE_ERROR);
+		assert(dc->state == DECODE_STATE_STOP ||
+		       dc->state == DECODE_STATE_ERROR);
 
-		switch (dc.command) {
+		switch (dc->command) {
 		case DECODE_COMMAND_START:
 		case DECODE_COMMAND_SEEK:
-			decoder_run();
+			decoder_run(dc);
 
-			dc.command = DECODE_COMMAND_NONE;
+			dc->command = DECODE_COMMAND_NONE;
 
 			player_signal();
 			break;
 
 		case DECODE_COMMAND_STOP:
-			dc.command = DECODE_COMMAND_NONE;
+			dc->command = DECODE_COMMAND_NONE;
 
 			player_signal();
 			break;
 
 		case DECODE_COMMAND_NONE:
-			decoder_wait();
+			decoder_wait(dc);
 			break;
 		}
-	} while (dc.command != DECODE_COMMAND_NONE || !dc.quit);
+	} while (dc->command != DECODE_COMMAND_NONE || !dc->quit);
 
-	decoder_unlock();
+	decoder_unlock(dc);
 
 	return NULL;
 }
 
-void decoder_thread_start(void)
+void
+decoder_thread_start(struct decoder_control *dc)
 {
 	GError *e = NULL;
 
-	assert(dc.thread == NULL);
+	assert(dc->thread == NULL);
 
-	dc.thread = g_thread_create(decoder_task, NULL, true, &e);
-	if (dc.thread == NULL)
+	dc->thread = g_thread_create(decoder_task, dc, true, &e);
+	if (dc->thread == NULL)
 		g_error("Failed to spawn decoder task: %s", e->message);
 }
diff --git a/src/decoder_thread.h b/src/decoder_thread.h
index 50ed7116e..a25564b87 100644
--- a/src/decoder_thread.h
+++ b/src/decoder_thread.h
@@ -20,6 +20,9 @@
 #ifndef MPD_DECODER_THREAD_H
 #define MPD_DECODER_THREAD_H
 
-void decoder_thread_start(void);
+struct decoder_control;
+
+void
+decoder_thread_start(struct decoder_control *dc);
 
 #endif