[gnome-remote-desktop] session-rdp: Add API to encode pending frame for RDP surface

[Jonas Ådahl <jadahl src gnome org>]

commit a52926933cdc015d614aa27617791640eea9b793
Author: Pascal Nowack <Pascal Nowack gmx de>
Date:   Fri Mar 19 18:06:24 2021 +0100

    session-rdp: Add API to encode pending frame for RDP surface
    
    Currently, gnome-remote-desktop encodes all pending frame data upon the
    end of the SuppressOutput PDU.
    When using the graphics pipeline, gnome-remote-desktop needs to be able
    to control the rate of the encodings.
    This means: gnome-remote-desktop needs to be able to suspend the
    encoding and continue it later.
    This is the case, when the client is too slow with the decoding.
    In that case, gnome-remote-desktop needs to immediately stop the
    encoding to not flood the client with too much new frame content.
    When the client acked enough pending frames, continue the encoding
    process.
    
    To be able to do that, add an API to encode the pending frame of an RDP
    surface.

 src/grd-session-rdp.c | 38 +++++++++++++++++++++++---------------
 src/grd-session-rdp.h |  3 +++
 2 files changed, 26 insertions(+), 15 deletions(-)
---
diff --git a/src/grd-session-rdp.c b/src/grd-session-rdp.c
index cc0f9f0..d910ff1 100644
--- a/src/grd-session-rdp.c
+++ b/src/grd-session-rdp.c
@@ -287,6 +287,28 @@ grd_session_rdp_take_buffer (GrdSessionRdp *session_rdp,
     }
 }
 
+void
+grd_session_rdp_maybe_encode_pending_frame (GrdSessionRdp *session_rdp,
+                                            GrdRdpSurface *rdp_surface)
+{
+  RdpPeerContext *rdp_peer_context;
+
+  g_assert (session_rdp->peer);
+  g_assert (session_rdp->peer->context);
+
+  rdp_peer_context = (RdpPeerContext *) session_rdp->peer->context;
+  if (!is_rdp_peer_flag_set (rdp_peer_context, RDP_PEER_ACTIVATED) ||
+      !is_rdp_peer_flag_set (rdp_peer_context, RDP_PEER_OUTPUT_ENABLED))
+    return;
+
+  if (!rdp_surface->pending_frame)
+    return;
+
+  grd_session_rdp_take_buffer (session_rdp,
+                               g_steal_pointer (&rdp_surface->pending_frame),
+                               rdp_surface->width, rdp_surface->height);
+}
+
 static gboolean
 is_mouse_pointer_hidden (uint32_t  width,
                          uint32_t  height,
@@ -1950,24 +1972,10 @@ static gboolean
 encode_pending_frames (gpointer user_data)
 {
   GrdSessionRdp *session_rdp = user_data;
-  RdpPeerContext *rdp_peer_context;
   GrdRdpSurface *rdp_surface;
 
-  g_assert (session_rdp->peer);
-  g_assert (session_rdp->peer->context);
-
-  rdp_peer_context = (RdpPeerContext *) session_rdp->peer->context;
-  if (!is_rdp_peer_flag_set (rdp_peer_context, RDP_PEER_ACTIVATED) ||
-      !is_rdp_peer_flag_set (rdp_peer_context, RDP_PEER_OUTPUT_ENABLED))
-    return G_SOURCE_CONTINUE;
-
   rdp_surface = session_rdp->rdp_surface;
-  if (!rdp_surface->pending_frame)
-    return G_SOURCE_CONTINUE;
-
-  grd_session_rdp_take_buffer (session_rdp,
-                               g_steal_pointer (&rdp_surface->pending_frame),
-                               rdp_surface->width, rdp_surface->height);
+  grd_session_rdp_maybe_encode_pending_frame (session_rdp, rdp_surface);
 
   return G_SOURCE_CONTINUE;
 }
diff --git a/src/grd-session-rdp.h b/src/grd-session-rdp.h
index 454f883..64c4a5b 100644
--- a/src/grd-session-rdp.h
+++ b/src/grd-session-rdp.h
@@ -47,6 +47,9 @@ void grd_session_rdp_take_buffer (GrdSessionRdp *session_rdp,
                                   uint16_t       width,
                                   uint16_t       height);
 
+void grd_session_rdp_maybe_encode_pending_frame (GrdSessionRdp *session_rdp,
+                                                 GrdRdpSurface *rdp_surface);
+
 void grd_session_rdp_update_pointer (GrdSessionRdp *session_rdp,
                                      uint16_t       hotspot_x,
                                      uint16_t       hotspot_y,