[vlc-devel] [PATCH 2/3] decoder: document vout/aout locking
robux4 at ycbcr.xyz
Fri Sep 6 12:19:49 CEST 2019
From: Thomas Guillem <thomas at gllm.fr>
src/input/decoder.c | 21 ++++++++++++++++++++-
1 file changed, 20 insertions(+), 1 deletion(-)
diff --git a/src/input/decoder.c b/src/input/decoder.c
index 48bb18c9719..288059e313c 100644
@@ -101,7 +101,26 @@ struct decoder_owner
vlc_cond_t wait_fifo; /* TODO: merge with wait_acknowledge */
- /* -- These variables need locking on write(only) -- */
+ * 3 threads can read/write these output variables, the DecoderThread, the
+ * input thread, and the ModuleThread. The ModuleThread is either the
+ * DecoderThread for synchronous modules or any thread for asynchronous
+ * modules.
+ * Asynchronous modules are responsible for serializing/locking every
+ * output calls in any thread as long as the decoder_UpdateVideoFormat() or
+ * decoder_NewPicture() calls are not concurrent, cf.
+ * decoder_UpdateVideoFormat() and decoder_NewPicture() notes.
+ * The ModuleThread 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 ModuleThread and DecoderThread are stopped (from DecoderDelete()).
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