[vlc-devel] [PATCH v4 3/9] video_output: move the dead (don't push) control handling in video_output

[Steve Lhomme]

Only the code that pushes code need to know it's not supposed to push anything
anymore. So far it was under a lock of the control thread. We use an atomic
boolean instead.

It doesn't matter if some command was being pushed at the time this flag is set.
In the end that command (and all previously enqueued commands) will be ignored
anyway. At this stage the vout thread is dead, the control FIFO will just be
cleaned a few lines later in vout_Release().
---
 src/video_output/control.c      | 14 ++------------
 src/video_output/control.h      |  2 --
 src/video_output/video_output.c | 10 +++++++---
 3 files changed, 9 insertions(+), 17 deletions(-)

diff --git a/src/video_output/control.c b/src/video_output/control.c
index fa5210bba9f..b22d0a03f66 100644
--- a/src/video_output/control.c
+++ b/src/video_output/control.c
@@ -38,7 +38,6 @@ void vout_control_Init(vout_control_t *ctrl)
 
     ctrl->is_held = false;
     ctrl->is_waiting = false;
-    ctrl->is_dead = false;
     ctrl->can_sleep = true;
     ARRAY_INIT(ctrl->cmd);
 }
@@ -49,20 +48,11 @@ void vout_control_Clean(vout_control_t *ctrl)
     ARRAY_RESET(ctrl->cmd);
 }
 
-void vout_control_Dead(vout_control_t *ctrl)
-{
-    vlc_mutex_lock(&ctrl->lock);
-    ctrl->is_dead = true;
-    vlc_mutex_unlock(&ctrl->lock);
-}
-
 static void vout_control_Push(vout_control_t *ctrl, vout_control_cmd_t *cmd)
 {
     vlc_mutex_lock(&ctrl->lock);
-    if (!ctrl->is_dead) {
-        ARRAY_APPEND(ctrl->cmd, *cmd);
-        vlc_cond_signal(&ctrl->wait_request);
-    }
+    ARRAY_APPEND(ctrl->cmd, *cmd);
+    vlc_cond_signal(&ctrl->wait_request);
     vlc_mutex_unlock(&ctrl->lock);
 }
 
diff --git a/src/video_output/control.h b/src/video_output/control.h
index 5976a0f6750..464bf349cc9 100644
--- a/src/video_output/control.h
+++ b/src/video_output/control.h
@@ -43,7 +43,6 @@ typedef struct {
     vlc_cond_t  wait_available;
 
     /* */
-    bool is_dead;
     bool can_sleep;
     bool is_waiting;
     bool is_held;
@@ -63,6 +62,5 @@ void vout_control_Release(vout_control_t *);
 
 /* control inside of the vout thread */
 int vout_control_Pop(vout_control_t *, vout_control_cmd_t *, vlc_tick_t deadline);
-void vout_control_Dead(vout_control_t *);
 
 #endif
diff --git a/src/video_output/video_output.c b/src/video_output/video_output.c
index 29b8b140e09..e3e9b112679 100644
--- a/src/video_output/video_output.c
+++ b/src/video_output/video_output.c
@@ -118,6 +118,7 @@ typedef struct vout_thread_sys_t
 
     /* Thread & synchronization */
     vout_control_t  control;
+    atomic_bool     control_is_dead; // do not push any more commands
     vlc_thread_t    thread;
 
     struct {
@@ -392,7 +393,8 @@ void vout_MouseState(vout_thread_t *vout, const vlc_mouse_t *mouse)
         video_mouse = *mouse;
     vlc_mutex_unlock(&sys->display_lock);
 
-    vout_control_PushMouse(&sys->control, &video_mouse);
+    if (!atomic_load(&sys->control_is_dead))
+        vout_control_PushMouse(&sys->control, &video_mouse);
 }
 
 void vout_PutSubpicture( vout_thread_t *vout, subpicture_t *subpic )
@@ -1971,7 +1973,8 @@ void vout_StopDisplay(vout_thread_t *vout)
 {
     vout_thread_sys_t *sys = VOUT_THREAD_TO_SYS(vout);
 
-    vout_control_PushTerminate(&sys->control);
+    if (!atomic_load(&sys->control_dead))
+        vout_control_PushTerminate(&sys->control);
     vlc_join(sys->thread, NULL);
 
     vout_ReleaseDisplay(sys);
@@ -2010,7 +2013,7 @@ void vout_Close(vout_thread_t *vout)
 
     vout_IntfDeinit(VLC_OBJECT(vout));
     vout_snapshot_End(sys->snapshot);
-    vout_control_Dead(&sys->control);
+    atomic_store(&sys->control_is_dead, true);
     vout_chrono_Clean(&sys->render);
 
     if (sys->spu)
@@ -2117,6 +2120,7 @@ vout_thread_t *vout_Create(vlc_object_t *object)
                spu_Create(vout, vout) : NULL;
 
     vout_control_Init(&sys->control);
+    atomic_init(&sys->control_is_dead, false);
 
     sys->title.show     = var_InheritBool(vout, "video-title-show");
     sys->title.timeout  = var_InheritInteger(vout, "video-title-timeout");
-- 
2.29.2