X-Git-Url: http://git.tuebingen.mpg.de/?p=paraslash.git;a=blobdiff_plain;f=osx_write.c;h=e34f03888c800ba5e157c89a4cc011aa66fc9469;hp=0f9d9605926a81fa5be0c4643ca6565fbe0391c2;hb=1c6fa9aa4483c491c4edf0129bc26478513324ed;hpb=c4bfb18b78b3935b8dbf68f70b219cfb2a192979

diff --git a/osx_write.c b/osx_write.c
index 0f9d9605..e34f0388 100644
--- a/osx_write.c
+++ b/osx_write.c
@@ -43,9 +43,28 @@ struct private_osx_write_data {
 	unsigned sample_format;
 	/** Number of channels of the current audio stream. */
 	unsigned channels;
-	/** Serializes access to buffer tree nodes. */
+	/**
+	 * Serializes access to buffer tree nodes between the writer and
+	 * the callback which runs in a different thread.
+	 */
 	int mutex;
-	/** The btr node of the callback. */
+	/**
+	 * The btr node of the callback.
+	 *
+	 * Although access to the btr node is serialized between the writer and
+	 * the callback via the above mutex, this does not stop other buffer
+	 * tree nodes, for example the decoder, to race against the osx
+	 * callback.
+	 *
+	 * However, since all operations on buffer tree nodes are local in the
+	 * sense that they only affect one level in the buffer tree (i.e.
+	 * parent or child nodes, but not the grandparent or the
+	 * grandchildren), we may work around this problem by using another
+	 * buffer tree node for the callback.
+	 *
+	 * The writer grabs the mutex in its post_select method and pushes down
+	 * the buffers to the callback node.
+	 */
 	struct btr_node *callback_btrn;
 };
 
@@ -217,18 +236,18 @@ e0:
 	return ret;
 }
 
-__malloc static void *osx_write_parse_config_or_die(const char *options)
+__malloc static void *osx_write_parse_config_or_die(int argc, char **argv)
 {
 	struct osx_write_args_info *conf = para_calloc(sizeof(*conf));
 
 	/* exits on errors */
-	osx_cmdline_parser_string(options, conf, "osx_write");
+	osx_write_cmdline_parser(argc, argv, conf);
 	return conf;
 }
 
 static void osx_free_config(void *conf)
 {
-	osx_cmdline_parser_free(conf);
+	osx_write_cmdline_parser_free(conf);
 }
 
 static void osx_write_close(struct writer_node *wn)
@@ -309,10 +328,9 @@ static void osx_write_post_select(__a_unused struct sched *s, struct task *t)
 	AudioOutputUnitStop(powd->audio_unit);
 	AudioUnitUninitialize(powd->audio_unit);
 	CloseComponent(powd->audio_unit);
-	btr_remove_node(powd->callback_btrn);
-	btr_free_node(powd->callback_btrn);
+	btr_remove_node(&powd->callback_btrn);
 remove_btrn:
-	btr_remove_node(btrn);
+	btr_remove_node(&wn->btrn);
 	PARA_NOTICE_LOG("%s\n", para_strerror(-ret));
 out:
 	t->error = ret;
@@ -327,7 +345,7 @@ void osx_write_init(struct writer *w)
 {
 	struct osx_write_args_info dummy;
 
-	osx_cmdline_parser_init(&dummy);
+	osx_write_cmdline_parser_init(&dummy);
 	w->close = osx_write_close;
 	w->pre_select = osx_write_pre_select;
 	w->post_select = osx_write_post_select;
@@ -337,5 +355,5 @@ void osx_write_init(struct writer *w)
 		.short_help = osx_write_args_info_help,
 		.detailed_help = osx_write_args_info_detailed_help
 	};
-	osx_cmdline_parser_free(&dummy);
+	osx_write_cmdline_parser_free(&dummy);
 }