[vlc-commits] vout/control: allow queueing asynchronous requests

[Rémi Denis-Courmont]

vlc | branch: master | Rémi Denis-Courmont <remi at remlab.net> | Mon Jan 28 22:18:29 2019 +0200| [3ea0d902fa615ff71f63998da7e5d4c9e075124b] | committer: Rémi Denis-Courmont

vout/control: allow queueing asynchronous requests

Asynchronous requests from the user interface should still be queued
without blocking, even if the video output is held by other processing.

For that, we need to release the mutex between Hold() and Release().

> http://git.videolan.org/gitweb.cgi/vlc.git/?a=commit;h=3ea0d902fa615ff71f63998da7e5d4c9e075124b
---

 src/video_output/control.c | 23 ++++++++++++++---------
 src/video_output/control.h |  3 ++-
 2 files changed, 16 insertions(+), 10 deletions(-)

diff --git a/src/video_output/control.c b/src/video_output/control.c
index 4fa1475258..dbcc3036ff 100644
--- a/src/video_output/control.c
+++ b/src/video_output/control.c
@@ -51,7 +51,7 @@ void vout_control_Init(vout_control_t *ctrl)
 {
     vlc_mutex_init(&ctrl->lock);
     vlc_cond_init(&ctrl->wait_request);
-    vlc_cond_init(&ctrl->wait_acknowledge);
+    vlc_cond_init(&ctrl->wait_available);
 
     ctrl->is_dead = false;
     ctrl->can_sleep = true;
@@ -69,16 +69,14 @@ void vout_control_Clean(vout_control_t *ctrl)
 
     vlc_mutex_destroy(&ctrl->lock);
     vlc_cond_destroy(&ctrl->wait_request);
-    vlc_cond_destroy(&ctrl->wait_acknowledge);
+    vlc_cond_destroy(&ctrl->wait_available);
 }
 
 void vout_control_Dead(vout_control_t *ctrl)
 {
     vlc_mutex_lock(&ctrl->lock);
     ctrl->is_dead = true;
-    vlc_cond_broadcast(&ctrl->wait_acknowledge);
     vlc_mutex_unlock(&ctrl->lock);
-
 }
 
 void vout_control_Push(vout_control_t *ctrl, vout_control_cmd_t *cmd)
@@ -137,13 +135,18 @@ void vout_control_PushString(vout_control_t *ctrl, int type, const char *string)
 void vout_control_Hold(vout_control_t *ctrl)
 {
     vlc_mutex_lock(&ctrl->lock);
-    while (!ctrl->is_waiting && !ctrl->is_dead)
-        vlc_cond_wait(&ctrl->wait_acknowledge, &ctrl->lock);
-    /* TODO: unlock to let other threads queue requests */
+    while (ctrl->is_held || !ctrl->is_waiting)
+        vlc_cond_wait(&ctrl->wait_available, &ctrl->lock);
+    ctrl->is_held = true;
+    vlc_mutex_unlock(&ctrl->lock);
 }
 
 void vout_control_Release(vout_control_t *ctrl)
 {
+    vlc_mutex_lock(&ctrl->lock);
+    assert(ctrl->is_held);
+    ctrl->is_held = false;
+    vlc_cond_signal(&ctrl->wait_available);
     vlc_mutex_unlock(&ctrl->lock);
 }
 
@@ -152,16 +155,18 @@ int vout_control_Pop(vout_control_t *ctrl, vout_control_cmd_t *cmd,
 {
     vlc_mutex_lock(&ctrl->lock);
     if (ctrl->cmd.i_size <= 0) {
-        vlc_cond_broadcast(&ctrl->wait_acknowledge);
-
         /* Spurious wakeups are perfectly fine */
         if (deadline != VLC_TICK_INVALID && ctrl->can_sleep) {
             ctrl->is_waiting = true;
+            vlc_cond_signal(&ctrl->wait_available);
             vlc_cond_timedwait(&ctrl->wait_request, &ctrl->lock, deadline);
             ctrl->is_waiting = false;
         }
     }
 
+    while (ctrl->is_held)
+        vlc_cond_wait(&ctrl->wait_available, &ctrl->lock);
+
     bool has_cmd;
     if (ctrl->cmd.i_size > 0) {
         has_cmd = true;
diff --git a/src/video_output/control.h b/src/video_output/control.h
index b05eabff65..9eb7ac32e3 100644
--- a/src/video_output/control.h
+++ b/src/video_output/control.h
@@ -82,12 +82,13 @@ void vout_control_cmd_Clean(vout_control_cmd_t *);
 typedef struct {
     vlc_mutex_t lock;
     vlc_cond_t  wait_request;
-    vlc_cond_t  wait_acknowledge;
+    vlc_cond_t  wait_available;
 
     /* */
     bool is_dead;
     bool can_sleep;
     bool is_waiting;
+    bool is_held;
     DECL_ARRAY(vout_control_cmd_t) cmd;
 } vout_control_t;