music_chunk: added assertions on the audio format

In !NDEBUG, remember which audio_format is stored in every chunk and
every pipe.  Check the audio_format of every new data block appended
to the music_chunk, and the format of every new chunk appended to the
music_pipe.

src/chunk.c

@@ -36,6 +36,19 @@ music_chunk_free(struct music_chunk *chunk)
 		tag_free(chunk->tag);
 }
 
+#ifndef NDEBUG
+bool
+music_chunk_check_format(const struct music_chunk *chunk,
+			 const struct audio_format *audio_format)
+{
+	assert(chunk != NULL);
+	assert(audio_format != NULL);
+
+	return chunk->length == 0 ||
+		audio_format_equals(&chunk->audio_format, audio_format);
+}
+#endif
+
 void *
 music_chunk_write(struct music_chunk *chunk,
 		  const struct audio_format *audio_format,
@@ -45,6 +58,8 @@ music_chunk_write(struct music_chunk *chunk,
 	const size_t frame_size = audio_format_frame_size(audio_format);
 	size_t num_frames;
 
+	assert(music_chunk_check_format(chunk, audio_format));
+
 	if (chunk->length == 0) {
 		/* if the chunk is empty, nobody has set bitRate and
 		   times yet */
@@ -57,6 +72,10 @@ music_chunk_write(struct music_chunk *chunk,
 	if (num_frames == 0)
 		return NULL;
 
+#ifndef NDEBUG
+	chunk->audio_format = *audio_format;
+#endif
+
 	*max_length_r = num_frames * frame_size;
 	return chunk->data + chunk->length;
 }
@@ -69,6 +88,7 @@ music_chunk_expand(struct music_chunk *chunk,
 
 	assert(chunk != NULL);
 	assert(chunk->length + length <= sizeof(chunk->data));
+	assert(audio_format_equals(&chunk->audio_format, audio_format));
 
 	chunk->length += length;
 

src/chunk.h

@@ -19,6 +19,10 @@
 #ifndef MPD_CHUNK_H
 #define MPD_CHUNK_H
 
+#ifndef NDEBUG
+#include "audio_format.h"
+#endif
+
 #include <stdbool.h>
 #include <stdint.h>
 #include <stddef.h>
@@ -57,6 +61,10 @@ struct music_chunk {
 
 	/** the data (probably PCM) */
 	char data[CHUNK_SIZE];
+
+#ifndef NDEBUG
+	struct audio_format audio_format;
+#endif
 };
 
 void
@@ -71,6 +79,16 @@ music_chunk_is_empty(const struct music_chunk *chunk)
 	return chunk->length == 0 && chunk->tag == NULL;
 }
 
+#ifndef NDEBUG
+/**
+ * Checks if the audio format if the chunk is equal to the specified
+ * audio_format.
+ */
+bool
+music_chunk_check_format(const struct music_chunk *chunk,
+			 const struct audio_format *audio_format);
+#endif
+
 /**
  * Prepares appending to the music chunk.  Returns a buffer where you
  * may write into.  After you are finished, call music_chunk_expand().

src/pipe.c

@@ -36,6 +36,10 @@ struct music_pipe {
 
 	/** a mutex which protects #head and #tail_r */
 	GMutex *mutex;
+
+#ifndef NDEBUG
+	struct audio_format audio_format;
+#endif
 };
 
 struct music_pipe *
@@ -48,6 +52,10 @@ music_pipe_new(void)
 	mp->size = 0;
 	mp->mutex = g_mutex_new();
 
+#ifndef NDEBUG
+	audio_format_clear(&mp->audio_format);
+#endif
+
 	return mp;
 }
 
@@ -61,6 +69,19 @@ music_pipe_free(struct music_pipe *mp)
 	g_free(mp);
 }
 
+#ifndef NDEBUG
+bool
+music_pipe_check_format(const struct music_pipe *pipe,
+			const struct audio_format *audio_format)
+{
+	assert(pipe != NULL);
+	assert(audio_format != NULL);
+
+	return !audio_format_defined(&pipe->audio_format) ||
+		audio_format_equals(&pipe->audio_format, audio_format);
+}
+#endif
+
 const struct music_chunk *
 music_pipe_peek(const struct music_pipe *mp)
 {
@@ -94,6 +115,9 @@ music_pipe_shift(struct music_pipe *mp)
 #ifndef NDEBUG
 		/* poison the "next" reference */
 		chunk->next = (void*)0x01010101;
+
+		if (mp->size == 0)
+			audio_format_clear(&mp->audio_format);
 #endif
 	}
 
@@ -118,6 +142,15 @@ music_pipe_push(struct music_pipe *mp, struct music_chunk *chunk)
 
 	g_mutex_lock(mp->mutex);
 
+	assert(mp->size > 0 || !audio_format_defined(&mp->audio_format));
+	assert(!audio_format_defined(&mp->audio_format) ||
+	       music_chunk_check_format(chunk, &mp->audio_format));
+
+#ifndef NDEBUG
+	if (!audio_format_defined(&mp->audio_format) && chunk->length > 0)
+		mp->audio_format = chunk->audio_format;
+#endif
+
 	chunk->next = NULL;
 	*mp->tail_r = chunk;
 	mp->tail_r = &chunk->next;

src/pipe.h

@@ -19,6 +19,12 @@
 #ifndef MPD_PIPE_H
 #define MPD_PIPE_H
 
+#ifndef NDEBUG
+#include <stdbool.h>
+
+struct audio_format;
+#endif
+
 struct music_chunk;
 struct music_buffer;
 
@@ -40,6 +46,16 @@ music_pipe_new(void);
 void
 music_pipe_free(struct music_pipe *mp);
 
+#ifndef NDEBUG
+/**
+ * Checks if the audio format if the chunk is equal to the specified
+ * audio_format.
+ */
+bool
+music_pipe_check_format(const struct music_pipe *pipe,
+			const struct audio_format *audio_format);
+#endif
+
 /**
  * Returns the first #music_chunk from the pipe.  Returns NULL if the
  * pipe is empty.

src/player_thread.c

@@ -313,6 +313,8 @@ play_chunk(struct song *song, struct music_chunk *chunk,
 {
 	bool success;
 
+	assert(music_chunk_check_format(chunk, format));
+
 	pc.elapsed_time = chunk->times;
 	pc.bit_rate = chunk->bit_rate;