input_stream: non-blocking I/O

Add GMutex, GCond attributes which will be used by callers to
conditionally wait on the stream.

Remove the (now-useless) plugin method buffer(), wait on GCond
instead.  Lock the input_stream before each method call.  Do the same
with the playlist plugins.

1 files changed, 15 insertions, 3 deletions

diff --git a/src/song_update.c b/src/song_update.c
index e2a845eef..e7279a6f6 100644
--- a/src/song_update.c
+++ b/src/song_update.c
@@ -131,6 +131,9 @@ song_file_update(struct song *song)
 
 	song->mtime = st.st_mtime;
 
+	GMutex *mutex = NULL;
+	GCond *cond;
+
 	do {
 		/* load file tag */
 		song->tag = decoder_plugin_tag_dup(plugin, path_fs);
@@ -141,8 +144,12 @@ song_file_update(struct song *song)
 		if (plugin->stream_tag != NULL) {
 			/* open the input_stream (if not already
 			   open) */
-			if (is == NULL)
-				is = input_stream_open(path_fs, NULL);
+			if (is == NULL) {
+				mutex = g_mutex_new();
+				cond = g_cond_new();
+				is = input_stream_open(path_fs, mutex, cond,
+						       NULL);
+			}
 
 			/* now try the stream_tag() method */
 			if (is != NULL) {
@@ -151,7 +158,7 @@ song_file_update(struct song *song)
 				if (song->tag != NULL)
 					break;
 
-				input_stream_seek(is, 0, SEEK_SET, NULL);
+				input_stream_lock_seek(is, 0, SEEK_SET, NULL);
 			}
 		}
 
@@ -161,6 +168,11 @@ song_file_update(struct song *song)
 	if (is != NULL)
 		input_stream_close(is);
 
+	if (mutex != NULL) {
+		g_cond_free(cond);
+		g_mutex_free(mutex);
+	}
+
 	if (song->tag != NULL && tag_is_empty(song->tag))
 		song->tag = tag_fallback(path_fs, song->tag);