[vlc-devel] [PATCH] Handle GET_PARAMETER keepalive responses during PAUSE

[Paul Clark]

Fixes ticket#14939

Because Demux() is not called during PAUSE the GET_PARAMETER keepalives are
sent by the TimeoutPrevention thread.  However this was not giving Live555
a chance to handle the responses through doEventLoop(), and so the responses
were queued up.  Because of a separate issue in handling pipelined
GET_PARAMETER responses in Live555 itself (now fixed, 2015-06-24), after two
GPs this would result in the loss of the PLAY response on resume, locking
everything up.

Even with the fix to Live555, queuing up all GP responses until the stream
is resumed is unpleasant and will eventually overflow Live555's response
buffer.

This fix calls the usual Live555 response handling mechanism for GPs sent
in the background thread during pause.  I have not added it to the normal
GP sends in Demux() because that calls doEventLoop() anyway, and to do so
would add a delay to normal processing.

TimeoutPrevention now requires access to p_demux itself, not just p_sys.
---
  modules/access/live555.cpp | 20 +++++++++++++++-----
  1 file changed, 15 insertions(+), 5 deletions(-)

diff --git a/modules/access/live555.cpp b/modules/access/live555.cpp
index fef590a..517ce58 100644
--- a/modules/access/live555.cpp
+++ b/modules/access/live555.cpp
@@ -172,7 +172,7 @@ typedef struct

  struct timeout_thread_t
  {
-    demux_sys_t  *p_sys;
+    demux_t     *p_demux;
      vlc_thread_t handle;
      bool         b_handle_keep_alive;
  };
@@ -1235,7 +1235,7 @@ static int Play( demux_t *p_demux )
              if( p_sys->p_timeout )
              {
                  memset( p_sys->p_timeout, 0, sizeof(timeout_thread_t) );
-                p_sys->p_timeout->p_sys = p_demux->p_sys; /* lol, 
object recursion :D */
+                p_sys->p_timeout->p_demux = p_demux;
                  if( vlc_clone( &p_sys->p_timeout->handle,  
TimeoutPrevention,
                                 p_sys->p_timeout, 
VLC_THREAD_PRIORITY_LOW ) )
                  {
@@ -2108,6 +2108,8 @@ VLC_NORETURN
  static void* TimeoutPrevention( void *p_data )
  {
      timeout_thread_t *p_timeout = (timeout_thread_t *)p_data;
+    demux_t *p_demux = p_timeout->p_demux;
+    demux_sys_t *p_sys = p_demux->p_sys;

      for( ;; )
      {
@@ -2117,12 +2119,20 @@ static void* TimeoutPrevention( void *p_data )
              char *psz_bye = NULL;
              int canc = vlc_savecancel ();

- p_timeout->p_sys->rtsp->sendGetParameterCommand( 
*p_timeout->p_sys->ms, NULL, psz_bye );
+            p_sys->rtsp->sendGetParameterCommand( *p_sys->ms, 
default_live555_callback, psz_bye );
+
+            if( !wait_Live555_response( p_demux ) )
+            {
+              msg_Err( p_demux, "GET_PARAMETER keepalive failed: %s",
+                       p_sys->env->getResultMsg() );
+              /* Just continue, worst case is we get timed out later */
+            }
+
              vlc_restorecancel (canc);
          }
-        p_timeout->p_sys->b_timeout_call = !p_timeout->b_handle_keep_alive;
+        p_sys->b_timeout_call = !p_timeout->b_handle_keep_alive;

-        msleep (((int64_t)p_timeout->p_sys->i_timeout - 2) * CLOCK_FREQ);
+        msleep (((int64_t)p_sys->i_timeout - 2) * CLOCK_FREQ);
      }
      vlc_assert_unreachable(); /* dead code */
  }
-- 
2.1.4