src/xvba_video.c: rewrite sync_surface()

src/xvba_video.c

@@ -135,6 +135,7 @@ destroy_surface(xvba_driver_data_t *driver_data, object_surface_p obj_surface)
 }
 
 // Query surface status
+// NOTE: also used for images
 int
 query_surface_status(
     xvba_driver_data_t *driver_data,
@@ -145,21 +146,22 @@ query_surface_status(
 {
     int status;
 
-    if (surface_status)
-        *surface_status = VASurfaceReady;
+    if (!surface_status)
+        abort(); /* coding error */
 
+    *surface_status = 0;
     if (!obj_surface)
-        return 0;
+        abort(); /* coding error */
 
     switch (obj_surface->va_surface_status) {
     case VASurfaceRendering: /* Rendering (XvBA level) */
         ASSERT(obj_surface->used_for_decoding);
         if (!obj_context)
-            return 0;
+            goto ok; /* Can be called with obj_context = NULL */
         if (!obj_context->xvba_decoder)
-            return 0;
+            abort(); /* coding error */
         if (!obj_surface->xvba_surface)
-            return 0;
+            goto ok;;
         status = xvba_sync_surface(
             obj_context->xvba_decoder,
             obj_surface->xvba_surface,
@@ -177,11 +179,22 @@ query_surface_status(
         if (status == XVBA_COMPLETED)
             obj_surface->va_surface_status = VASurfaceReady;
         break;
+    default:
+        /* NOTE: va_surface_status could be 0 or VASurfaceSkipped
+         * in both cases it is safe to be used. */
+        if ((obj_surface->va_surface_status == 0) ||
+            (obj_surface->va_surface_status == VASurfaceSkipped)) {
+            goto ok;
+        }
+        break;
     }
 
-    if (surface_status)
     *surface_status = obj_surface->va_surface_status;
     return 0;
+
+ok: /* State is safe to continue surface is not used for decoding */
+    *surface_status = VASurfaceReady;
+    return 0;
 }
 
 // Synchronize surface
@@ -195,9 +208,10 @@ sync_surface(
     VASurfaceStatus surface_status;
     int status;
 
-    while ((status = query_surface_status(driver_data, obj_context, obj_surface, &surface_status)) == 0 &&
-           surface_status != VASurfaceReady)
+    do {
+        status = query_surface_status(driver_data, obj_context, obj_surface, &surface_status);
         delay_usec(XVBA_SYNC_DELAY);
+    } while(surface_status != VASurfaceReady && status != 0);
     return status;
 }