backends: Move HW cursor inhibitors to MetaBackend

We are aiming for a split of HW and SW cursor rendering management.
Given the HW plane is a limited resource and the amount of cursor
renderers may be >1 (due to tablets, even though we currently use an
always-software cursor renderer there), it would ideally be able to
switch between renderers.

Being MetaCursorRenderer not really a singleton, having cursor
inhibitor accounting here doesn't pan out. Make it MetaBackend API
so all cursor renderers get the same picture.

https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1403

src/backends/meta-backend-private.h

@@ -196,4 +196,12 @@ GList * meta_backend_get_gpus (MetaBackend *backend);
 WacomDeviceDatabase * meta_backend_get_wacom_database (MetaBackend *backend);
 #endif
 
+void meta_backend_add_hw_cursor_inhibitor (MetaBackend           *backend,
+                                           MetaHwCursorInhibitor *inhibitor);
+
+void meta_backend_remove_hw_cursor_inhibitor (MetaBackend           *backend,
+                                              MetaHwCursorInhibitor *inhibitor);
+
+gboolean meta_backend_is_hw_cursors_inhibited (MetaBackend *backend);
+
 #endif /* META_BACKEND_PRIVATE_H */

src/backends/meta-backend.c

@@ -53,6 +53,7 @@
 
 #include <stdlib.h>
 
+#include "backends/meta-cursor-renderer.h"
 #include "backends/meta-cursor-tracker-private.h"
 #include "backends/meta-idle-monitor-private.h"
 #include "backends/meta-input-settings-private.h"
@@ -150,6 +151,7 @@ struct _MetaBackendPrivate
   ClutterActor *stage;
 
   GList *gpus;
+  GList *hw_cursor_inhibitors;
 
   gboolean is_pointer_position_initialized;
 
@@ -1503,3 +1505,40 @@ meta_backend_get_wacom_database (MetaBackend *backend)
   return priv->wacom_db;
 }
 #endif
+
+void
+meta_backend_add_hw_cursor_inhibitor (MetaBackend           *backend,
+                                      MetaHwCursorInhibitor *inhibitor)
+{
+  MetaBackendPrivate *priv = meta_backend_get_instance_private (backend);
+
+  priv->hw_cursor_inhibitors = g_list_prepend (priv->hw_cursor_inhibitors,
+                                               inhibitor);
+}
+
+void
+meta_backend_remove_hw_cursor_inhibitor (MetaBackend           *backend,
+                                         MetaHwCursorInhibitor *inhibitor)
+{
+  MetaBackendPrivate *priv = meta_backend_get_instance_private (backend);
+
+  priv->hw_cursor_inhibitors = g_list_remove (priv->hw_cursor_inhibitors,
+                                              inhibitor);
+}
+
+gboolean
+meta_backend_is_hw_cursors_inhibited (MetaBackend *backend)
+{
+  MetaBackendPrivate *priv = meta_backend_get_instance_private (backend);
+  GList *l;
+
+  for (l = priv->hw_cursor_inhibitors; l; l = l->next)
+    {
+      MetaHwCursorInhibitor *inhibitor = l->data;
+
+      if (meta_hw_cursor_inhibitor_is_cursor_inhibited (inhibitor))
+        return TRUE;
+    }
+
+  return FALSE;
+}

src/backends/meta-cursor-renderer.c

@@ -81,7 +81,7 @@ static guint signals[LAST_SIGNAL];
 
 G_DEFINE_TYPE_WITH_PRIVATE (MetaCursorRenderer, meta_cursor_renderer, G_TYPE_OBJECT);
 
-static gboolean
+gboolean
 meta_hw_cursor_inhibitor_is_cursor_inhibited (MetaHwCursorInhibitor *inhibitor)
 {
   MetaHwCursorInhibitorInterface *iface =
@@ -475,46 +475,6 @@ meta_cursor_renderer_is_overlay_visible (MetaCursorRenderer *renderer)
   return meta_overlay_is_visible (priv->stage_overlay);
 }
 
-void
-meta_cursor_renderer_add_hw_cursor_inhibitor (MetaCursorRenderer    *renderer,
-                                              MetaHwCursorInhibitor *inhibitor)
-{
-  MetaCursorRendererPrivate *priv =
-    meta_cursor_renderer_get_instance_private (renderer);
-
-  priv->hw_cursor_inhibitors = g_list_prepend (priv->hw_cursor_inhibitors,
-                                               inhibitor);
-}
-
-void
-meta_cursor_renderer_remove_hw_cursor_inhibitor (MetaCursorRenderer    *renderer,
-                                                 MetaHwCursorInhibitor *inhibitor)
-{
-  MetaCursorRendererPrivate *priv =
-    meta_cursor_renderer_get_instance_private (renderer);
-
-  priv->hw_cursor_inhibitors = g_list_remove (priv->hw_cursor_inhibitors,
-                                              inhibitor);
-}
-
-gboolean
-meta_cursor_renderer_is_hw_cursors_inhibited (MetaCursorRenderer *renderer)
-{
-  MetaCursorRendererPrivate *priv =
-    meta_cursor_renderer_get_instance_private (renderer);
-  GList *l;
-
-  for (l = priv->hw_cursor_inhibitors; l; l = l->next)
-    {
-      MetaHwCursorInhibitor *inhibitor = l->data;
-
-      if (meta_hw_cursor_inhibitor_is_cursor_inhibited (inhibitor))
-        return TRUE;
-    }
-
-  return FALSE;
-}
-
 ClutterInputDevice *
 meta_cursor_renderer_get_input_device (MetaCursorRenderer *renderer)
 {

src/backends/meta-cursor-renderer.h

@@ -41,6 +41,8 @@ struct _MetaHwCursorInhibitorInterface
   gboolean (* is_cursor_inhibited) (MetaHwCursorInhibitor *inhibitor);
 };
 
+gboolean meta_hw_cursor_inhibitor_is_cursor_inhibited (MetaHwCursorInhibitor *inhibitor);
+
 #define META_TYPE_CURSOR_RENDERER (meta_cursor_renderer_get_type ())
 G_DECLARE_DERIVABLE_TYPE (MetaCursorRenderer, meta_cursor_renderer,
                           META, CURSOR_RENDERER, GObject);
@@ -66,14 +68,6 @@ MetaCursorSprite * meta_cursor_renderer_get_cursor (MetaCursorRenderer *renderer
 
 gboolean meta_cursor_renderer_is_overlay_visible (MetaCursorRenderer *renderer);
 
-void meta_cursor_renderer_add_hw_cursor_inhibitor (MetaCursorRenderer    *renderer,
-                                                   MetaHwCursorInhibitor *inhibitor);
-
-void meta_cursor_renderer_remove_hw_cursor_inhibitor (MetaCursorRenderer    *renderer,
-                                                      MetaHwCursorInhibitor *inhibitor);
-
-gboolean meta_cursor_renderer_is_hw_cursors_inhibited (MetaCursorRenderer *renderer);
-
 graphene_rect_t meta_cursor_renderer_calculate_rect (MetaCursorRenderer *renderer,
                                                      MetaCursorSprite   *cursor_sprite);
 

src/backends/meta-screen-cast-area-stream-src.c

@@ -83,19 +83,6 @@ get_backend (MetaScreenCastAreaStreamSrc *area_src)
   return meta_screen_cast_get_backend (screen_cast);
 }
 
-static MetaCursorRenderer *
-get_cursor_renderer (MetaScreenCastAreaStreamSrc *area_src)
-{
-  MetaScreenCastStreamSrc *src = META_SCREEN_CAST_STREAM_SRC (area_src);
-  MetaScreenCastStream *stream = meta_screen_cast_stream_src_get_stream (src);
-  MetaScreenCastSession *session = meta_screen_cast_stream_get_session (stream);
-  MetaScreenCast *screen_cast =
-    meta_screen_cast_session_get_screen_cast (session);
-  MetaBackend *backend = meta_screen_cast_get_backend (screen_cast);
-
-  return meta_backend_get_cursor_renderer (backend);
-}
-
 static void
 meta_screen_cast_area_stream_src_get_specs (MetaScreenCastStreamSrc *src,
                                             int                     *width,
@@ -202,14 +189,14 @@ cursor_changed (MetaCursorTracker           *cursor_tracker,
 static void
 inhibit_hw_cursor (MetaScreenCastAreaStreamSrc *area_src)
 {
-  MetaCursorRenderer *cursor_renderer;
   MetaHwCursorInhibitor *inhibitor;
+  MetaBackend *backend;
 
   g_return_if_fail (!area_src->hw_cursor_inhibited);
 
-  cursor_renderer = get_cursor_renderer (area_src);
+  backend = get_backend (area_src);
   inhibitor = META_HW_CURSOR_INHIBITOR (area_src);
-  meta_cursor_renderer_add_hw_cursor_inhibitor (cursor_renderer, inhibitor);
+  meta_backend_add_hw_cursor_inhibitor (backend, inhibitor);
 
   area_src->hw_cursor_inhibited = TRUE;
 }
@@ -217,14 +204,14 @@ inhibit_hw_cursor (MetaScreenCastAreaStreamSrc *area_src)
 static void
 uninhibit_hw_cursor (MetaScreenCastAreaStreamSrc *area_src)
 {
-  MetaCursorRenderer *cursor_renderer;
   MetaHwCursorInhibitor *inhibitor;
+  MetaBackend *backend;
 
   g_return_if_fail (area_src->hw_cursor_inhibited);
 
-  cursor_renderer = get_cursor_renderer (area_src);
+  backend = get_backend (area_src);
   inhibitor = META_HW_CURSOR_INHIBITOR (area_src);
-  meta_cursor_renderer_remove_hw_cursor_inhibitor (cursor_renderer, inhibitor);
+  meta_backend_remove_hw_cursor_inhibitor (backend, inhibitor);
 
   area_src->hw_cursor_inhibited = FALSE;
 }

src/backends/meta-screen-cast-monitor-stream-src.c

@@ -236,30 +236,17 @@ cursor_changed (MetaCursorTracker              *cursor_tracker,
   sync_cursor_state (monitor_src);
 }
 
-static MetaCursorRenderer *
-get_cursor_renderer (MetaScreenCastMonitorStreamSrc *monitor_src)
-{
-  MetaScreenCastStreamSrc *src = META_SCREEN_CAST_STREAM_SRC (monitor_src);
-  MetaScreenCastStream *stream = meta_screen_cast_stream_src_get_stream (src);
-  MetaScreenCastSession *session = meta_screen_cast_stream_get_session (stream);
-  MetaScreenCast *screen_cast =
-    meta_screen_cast_session_get_screen_cast (session);
-  MetaBackend *backend = meta_screen_cast_get_backend (screen_cast);
-
-  return meta_backend_get_cursor_renderer (backend);
-}
-
 static void
 inhibit_hw_cursor (MetaScreenCastMonitorStreamSrc *monitor_src)
 {
-  MetaCursorRenderer *cursor_renderer;
   MetaHwCursorInhibitor *inhibitor;
+  MetaBackend *backend;
 
   g_return_if_fail (!monitor_src->hw_cursor_inhibited);
 
-  cursor_renderer = get_cursor_renderer (monitor_src);
+  backend = get_backend (monitor_src);
   inhibitor = META_HW_CURSOR_INHIBITOR (monitor_src);
-  meta_cursor_renderer_add_hw_cursor_inhibitor (cursor_renderer, inhibitor);
+  meta_backend_add_hw_cursor_inhibitor (backend, inhibitor);
 
   monitor_src->hw_cursor_inhibited = TRUE;
 }
@@ -267,14 +254,14 @@ inhibit_hw_cursor (MetaScreenCastMonitorStreamSrc *monitor_src)
 static void
 uninhibit_hw_cursor (MetaScreenCastMonitorStreamSrc *monitor_src)
 {
-  MetaCursorRenderer *cursor_renderer;
   MetaHwCursorInhibitor *inhibitor;
+  MetaBackend *backend;
 
   g_return_if_fail (monitor_src->hw_cursor_inhibited);
 
-  cursor_renderer = get_cursor_renderer (monitor_src);
+  backend = get_backend (monitor_src);
   inhibitor = META_HW_CURSOR_INHIBITOR (monitor_src);
-  meta_cursor_renderer_remove_hw_cursor_inhibitor (cursor_renderer, inhibitor);
+  meta_backend_remove_hw_cursor_inhibitor (backend, inhibitor);
 
   monitor_src->hw_cursor_inhibited = FALSE;
 }

src/backends/native/meta-cursor-renderer-native.c

@@ -872,6 +872,10 @@ should_have_hw_cursor (MetaCursorRenderer *renderer,
                        MetaCursorSprite   *cursor_sprite,
                        GList              *gpus)
 {
+  MetaCursorRendererNative *cursor_renderer_native =
+    META_CURSOR_RENDERER_NATIVE (renderer);
+  MetaCursorRendererNativePrivate *priv =
+    meta_cursor_renderer_native_get_instance_private (cursor_renderer_native);
   CoglTexture *texture;
   MetaMonitorTransform transform;
   float scale;
@@ -880,7 +884,7 @@ should_have_hw_cursor (MetaCursorRenderer *renderer,
   if (!cursor_sprite)
     return FALSE;
 
-  if (meta_cursor_renderer_is_hw_cursors_inhibited (renderer))
+  if (meta_backend_is_hw_cursors_inhibited (priv->backend))
     return FALSE;
 
   for (l = gpus; l; l = l->next)