[vlc-devel] [PATCH] decoder: document vout/aout locking

[Thomas Guillem]

---
 src/input/decoder.c | 15 +++++++++++++--
 1 file changed, 13 insertions(+), 2 deletions(-)

diff --git a/src/input/decoder.c b/src/input/decoder.c
index 782dc0a422..8a1227a2d2 100644
--- a/src/input/decoder.c
+++ b/src/input/decoder.c
@@ -101,9 +101,20 @@ struct decoder_owner
     vlc_cond_t  wait_acknowledge;
     vlc_cond_t  wait_fifo; /* TODO: merge with wait_acknowledge */
 
-    /* -- These variables need locking on write(only) -- */
+    /* -- These variables need locking on write(only) --
+     * 3 threads can read/write these output variables, the DecoderThread, the
+     * input thread, and the OutputThread. The OutputThread is either the
+     * DecoderThread for synchronous modules or any threads for asynchronous
+     * modules. The asynchronous module is responsible for serializing/locking
+     * every output calls, cf. decoder_UpdateVideoFormat() and
+     * decoder_NewPicture() notes. The OutputThread is the owner of these
+     * variables, it should hold the lock when writing them but doesn't have to
+     * hold it when using them. The DecoderThread should always hold the lock
+     * when reading/using aout/vouts. The input thread can read these variables
+     * in order to stop outputs, when both OutputThread and DecoderThread are
+     * stopped (from DecoderDelete()).
+     */
     audio_output_t *p_aout;
-
     vout_thread_t   *p_vout;
 
     /* -- Theses variables need locking on read *and* write -- */
-- 
2.20.1