[mutter] screen-cast/virtual-src: Don't recreate the virtual monitor on resizes

[Marge Bot <marge-bot src gnome org>]

commit 4de740c7a3f1161d734a244036f584d86a7d8674
Author: Jonas Ådahl <jadahl gmail com>
Date:   Thu Feb 3 11:45:18 2022 +0100

    screen-cast/virtual-src: Don't recreate the virtual monitor on resizes
    
    Keep the virtual monitor around if it's being resized. This reduces the
    number of unnecessary object rebuilding that happen during monitor
    rebuilding.
    
    This changes finalize() vfunc into a dispose() vfunc in the abstract
    stream source object implementation, as it needs the abstract stream
    source object to close the stream early, so that various signal
    listeners get disconnected early.
    
    Closes: https://gitlab.gnome.org/GNOME/mutter/-/issues/1904
    Part-of: <https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/2270>

 src/backends/meta-screen-cast-stream-src.c         | 12 +++++-----
 src/backends/meta-screen-cast-virtual-stream-src.c | 28 +++++++++++++++++++---
 2 files changed, 31 insertions(+), 9 deletions(-)
---
diff --git a/src/backends/meta-screen-cast-stream-src.c b/src/backends/meta-screen-cast-stream-src.c
index e801324f03..e86f9a2b7c 100644
--- a/src/backends/meta-screen-cast-stream-src.c
+++ b/src/backends/meta-screen-cast-stream-src.c
@@ -1213,7 +1213,8 @@ create_pipewire_source (MetaScreenCastStreamSrc *src)
                         G_IO_IN | G_IO_ERR);
 
   pw_loop_enter (pipewire_source->pipewire_loop);
-  g_source_attach (&pipewire_source->base, NULL);
+  g_source_attach (source, NULL);
+  g_source_unref (source);
 
   return pipewire_source;
 }
@@ -1285,7 +1286,7 @@ meta_screen_cast_stream_src_get_stream (MetaScreenCastStreamSrc *src)
 }
 
 static void
-meta_screen_cast_stream_src_finalize (GObject *object)
+meta_screen_cast_stream_src_dispose (GObject *object)
 {
   MetaScreenCastStreamSrc *src = META_SCREEN_CAST_STREAM_SRC (object);
   MetaScreenCastStreamSrcPrivate *priv =
@@ -1298,10 +1299,9 @@ meta_screen_cast_stream_src_finalize (GObject *object)
   g_clear_pointer (&priv->dmabuf_handles, g_hash_table_destroy);
   g_clear_pointer (&priv->pipewire_core, pw_core_disconnect);
   g_clear_pointer (&priv->pipewire_context, pw_context_destroy);
-  g_source_destroy (&priv->pipewire_source->base);
-  g_source_unref (&priv->pipewire_source->base);
+  g_clear_pointer ((GSource **) &priv->pipewire_source, g_source_destroy);
 
-  G_OBJECT_CLASS (meta_screen_cast_stream_src_parent_class)->finalize (object);
+  G_OBJECT_CLASS (meta_screen_cast_stream_src_parent_class)->dispose (object);
 }
 
 static void
@@ -1360,7 +1360,7 @@ meta_screen_cast_stream_src_class_init (MetaScreenCastStreamSrcClass *klass)
 {
   GObjectClass *object_class = G_OBJECT_CLASS (klass);
 
-  object_class->finalize = meta_screen_cast_stream_src_finalize;
+  object_class->dispose = meta_screen_cast_stream_src_dispose;
   object_class->set_property = meta_screen_cast_stream_src_set_property;
   object_class->get_property = meta_screen_cast_stream_src_get_property;
 
diff --git a/src/backends/meta-screen-cast-virtual-stream-src.c 
b/src/backends/meta-screen-cast-virtual-stream-src.c
index 47a917da98..3341aedd9b 100644
--- a/src/backends/meta-screen-cast-virtual-stream-src.c
+++ b/src/backends/meta-screen-cast-virtual-stream-src.c
@@ -312,8 +312,6 @@ meta_screen_cast_virtual_stream_src_disable (MetaScreenCastStreamSrc *src)
     case META_SCREEN_CAST_CURSOR_MODE_HIDDEN:
       break;
     }
-
-  g_clear_object (&virtual_src->virtual_monitor);
 }
 
 static gboolean
@@ -526,12 +524,20 @@ ensure_virtual_monitor (MetaScreenCastVirtualStreamSrc *virtual_src,
       MetaCrtcMode *crtc_mode =
         meta_virtual_monitor_get_crtc_mode (virtual_monitor);
       const MetaCrtcModeInfo *mode_info = meta_crtc_mode_get_info (crtc_mode);
+      float refresh_rate;
 
       if (mode_info->width == video_format->size.width &&
           mode_info->height == video_format->size.height)
         return;
 
-      g_clear_object (&virtual_src->virtual_monitor);
+      refresh_rate = ((float) video_format->max_framerate.num /
+                      video_format->max_framerate.denom);
+      meta_virtual_monitor_set_mode (virtual_monitor,
+                                     video_format->size.width,
+                                     video_format->size.height,
+                                     refresh_rate);
+      meta_monitor_manager_reload (monitor_manager);
+      return;
     }
 
   virtual_monitor = create_virtual_monitor (virtual_src, video_format, &error);
@@ -585,6 +591,19 @@ hw_cursor_inhibitor_iface_init (MetaHwCursorInhibitorInterface *iface)
     meta_screen_cast_virtual_stream_src_is_cursor_inhibited;
 }
 
+static void
+meta_screen_cast_virtual_stream_src_dispose (GObject *object)
+{
+  MetaScreenCastVirtualStreamSrc *virtual_src =
+    META_SCREEN_CAST_VIRTUAL_STREAM_SRC (object);
+  GObjectClass *parent_class =
+    G_OBJECT_CLASS (meta_screen_cast_virtual_stream_src_parent_class);
+
+  parent_class->dispose (object);
+
+  g_clear_object (&virtual_src->virtual_monitor);
+}
+
 static void
 meta_screen_cast_virtual_stream_src_init (MetaScreenCastVirtualStreamSrc *virtual_src)
 {
@@ -593,9 +612,12 @@ meta_screen_cast_virtual_stream_src_init (MetaScreenCastVirtualStreamSrc *virtua
 static void
 meta_screen_cast_virtual_stream_src_class_init (MetaScreenCastVirtualStreamSrcClass *klass)
 {
+  GObjectClass *object_class = G_OBJECT_CLASS (klass);
   MetaScreenCastStreamSrcClass *src_class =
     META_SCREEN_CAST_STREAM_SRC_CLASS (klass);
 
+  object_class->dispose = meta_screen_cast_virtual_stream_src_dispose;
+
   src_class->get_specs = meta_screen_cast_virtual_stream_src_get_specs;
   src_class->enable = meta_screen_cast_virtual_stream_src_enable;
   src_class->disable = meta_screen_cast_virtual_stream_src_disable;