cursor-renderer: Add API to allow inhibiting HW cursor

There may be reasons to temporarly inhibit the HW cursor under certain
circumstances. Allow adding such inhibitations by adding API to the
cursor renderer to allow API users to add generic inhibitors with
whatever logic is deemed necessary.

https://gitlab.gnome.org/GNOME/mutter/merge_requests/357

src/backends/meta-cursor-renderer.c

@@ -34,6 +34,9 @@
 #include "meta/meta-backend.h"
 #include "meta/util.h"
 
+G_DEFINE_INTERFACE (MetaHwCursorInhibitor, meta_hw_cursor_inhibitor,
+                    G_TYPE_OBJECT)
+
 struct _MetaCursorRendererPrivate
 {
   float current_x;
@@ -43,6 +46,8 @@ struct _MetaCursorRendererPrivate
   MetaOverlay *stage_overlay;
   gboolean handled_by_backend;
   guint post_paint_func_id;
+
+  GList *hw_cursor_inhibitors;
 };
 typedef struct _MetaCursorRendererPrivate MetaCursorRendererPrivate;
 
@@ -54,6 +59,21 @@ static guint signals[LAST_SIGNAL];
 
 G_DEFINE_TYPE_WITH_PRIVATE (MetaCursorRenderer, meta_cursor_renderer, G_TYPE_OBJECT);
 
+static gboolean
+meta_hw_cursor_inhibitor_is_cursor_sprite_inhibited (MetaHwCursorInhibitor *inhibitor,
+                                                     MetaCursorSprite      *cursor_sprite)
+{
+  MetaHwCursorInhibitorInterface *iface =
+    META_HW_CURSOR_INHIBITOR_GET_IFACE (inhibitor);
+
+  return iface->is_cursor_sprite_inhibited (inhibitor, cursor_sprite);
+}
+
+static void
+meta_hw_cursor_inhibitor_default_init (MetaHwCursorInhibitorInterface *iface)
+{
+}
+
 void
 meta_cursor_renderer_emit_painted (MetaCursorRenderer *renderer,
                                    MetaCursorSprite   *cursor_sprite)
@@ -282,3 +302,45 @@ meta_cursor_renderer_get_cursor (MetaCursorRenderer *renderer)
 
   return priv->displayed_cursor;
 }
+
+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,
+                                              MetaCursorSprite   *cursor_sprite)
+{
+  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_sprite_inhibited (inhibitor,
+                                                               cursor_sprite))
+        return TRUE;
+    }
+
+  return FALSE;
+}