[Spice-devel] [PATCH v3] display-gst: small refactor get_decoded_frame()

[Victor Toso]

From: Victor Toso <me at victortoso.com>

Small refactor to make each code block a bit more obvious.

This code should (1) find the @buffer in the queue; (2) remove all old
elements from queue. That perfectly fit in two loops in sequence, but
they don't need to be nested and they don't need to use the same
pointer (gstframe).

As @num_frames_dropped is only used in the second block, this was
moved as well, together with the debug.

Signed-off-by: Victor Toso <victortoso at redhat.com>
---
 src/channel-display-gst.c | 34 ++++++++++++++++------------------
 1 file changed, 16 insertions(+), 18 deletions(-)

diff --git a/src/channel-display-gst.c b/src/channel-display-gst.c
index 4e66122..584e95b 100644
--- a/src/channel-display-gst.c
+++ b/src/channel-display-gst.c
@@ -212,8 +212,6 @@ static void schedule_frame(SpiceGstDecoder *decoder)
  */
 static SpiceGstFrame *get_decoded_frame(SpiceGstDecoder *decoder, GstBuffer *buffer)
 {
-    guint num_frames_dropped = 0;
-
     /* Gstreamer sometimes returns the same buffer twice
      * or buffers that have a modified, and thus unrecognizable, PTS.
      * Blindly removing frames from the decoding_queue until we find a
@@ -226,27 +224,27 @@ static SpiceGstFrame *get_decoded_frame(SpiceGstDecoder *decoder, GstBuffer *buf
     while (l) {
         gstframe = l->data;
         if (gstframe->timestamp == GST_BUFFER_PTS(buffer)) {
-
-            /* Now that we know there is a match, remove it and the older
-             * frames from the decoding queue.
-             */
-            while ((gstframe = g_queue_pop_head(decoder->decoding_queue))) {
-                if (gstframe->timestamp == GST_BUFFER_PTS(buffer)) {
-                    break;
-                }
-                /* The GStreamer pipeline dropped the corresponding
-                 * buffer.
-                 */
-                num_frames_dropped++;
-                free_gst_frame(gstframe);
-            }
             break;
         }
         gstframe = NULL;
         l = l->next;
     }
-    if (num_frames_dropped != 0) {
-        SPICE_DEBUG("the GStreamer pipeline dropped %u frames", num_frames_dropped);
+
+    if (gstframe != NULL) {
+        /* Now that we know there is a match, remove it and the older
+         * frames from the decoding queue */
+        SpiceGstFrame *late_frame;
+        guint num_frames_dropped = 0;
+
+        /* The GStreamer pipeline dropped the corresponding buffer. */
+        while ((late_frame = g_queue_pop_head(decoder->decoding_queue)) != gstframe) {
+            num_frames_dropped++;
+            free_gst_frame(late_frame);
+        }
+
+        if (num_frames_dropped != 0) {
+            SPICE_DEBUG("the GStreamer pipeline dropped %u frames", num_frames_dropped);
+        }
     }
     return gstframe;
 }
-- 
2.20.1