[mutter] cursor-renderer: Add API to allow inhibiting HW cursor

[Jonas Ådahl <jadahl src gnome org>]

commit 79d99cbe3feda7b609c67a3d1fc46c289ac23bfc
Author: Jonas Ådahl <jadahl gmail com>
Date:   Thu Sep 13 11:28:51 2018 +0200

    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               | 62 +++++++++++++++++++++++
 src/backends/meta-cursor-renderer.h               | 22 ++++++++
 src/backends/native/meta-cursor-renderer-native.c |  4 ++
 3 files changed, 88 insertions(+)
---
diff --git a/src/backends/meta-cursor-renderer.c b/src/backends/meta-cursor-renderer.c
index 1f76206f8..34a7f91d8 100644
--- a/src/backends/meta-cursor-renderer.c
+++ b/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;
+}
diff --git a/src/backends/meta-cursor-renderer.h b/src/backends/meta-cursor-renderer.h
index e1d5f8d42..60f1dbe15 100644
--- a/src/backends/meta-cursor-renderer.h
+++ b/src/backends/meta-cursor-renderer.h
@@ -27,8 +27,21 @@
 
 #include <glib-object.h>
 
+#include "backends/meta-backend-types.h"
 #include "backends/meta-cursor.h"
 
+#define META_TYPE_HW_CURSOR_INHIBITOR (meta_hw_cursor_inhibitor_get_type ())
+G_DECLARE_INTERFACE (MetaHwCursorInhibitor, meta_hw_cursor_inhibitor,
+                     META, HW_CURSOR_INHIBITOR, GObject)
+
+struct _MetaHwCursorInhibitorInterface
+{
+  GTypeInterface parent_iface;
+
+  gboolean (* is_cursor_sprite_inhibited) (MetaHwCursorInhibitor *inhibitor,
+                                           MetaCursorSprite      *cursor_sprite);
+};
+
 #define META_TYPE_CURSOR_RENDERER (meta_cursor_renderer_get_type ())
 G_DECLARE_DERIVABLE_TYPE (MetaCursorRenderer, meta_cursor_renderer,
                           META, CURSOR_RENDERER, GObject);
@@ -54,6 +67,15 @@ void meta_cursor_renderer_force_update (MetaCursorRenderer *renderer);
 
 MetaCursorSprite * meta_cursor_renderer_get_cursor (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,
+                                                       MetaCursorSprite   *cursor_sprite);
+
 ClutterRect meta_cursor_renderer_calculate_rect (MetaCursorRenderer *renderer,
                                                  MetaCursorSprite   *cursor_sprite);
 
diff --git a/src/backends/native/meta-cursor-renderer-native.c 
b/src/backends/native/meta-cursor-renderer-native.c
index 4fd7b1736..d32548344 100644
--- a/src/backends/native/meta-cursor-renderer-native.c
+++ b/src/backends/native/meta-cursor-renderer-native.c
@@ -586,6 +586,10 @@ should_have_hw_cursor (MetaCursorRenderer *renderer,
   if (!cursor_sprite)
     return FALSE;
 
+  if (meta_cursor_renderer_is_hw_cursors_inhibited (renderer,
+                                                    cursor_sprite))
+    return FALSE;
+
   for (l = gpus; l; l = l->next)
     {
       MetaGpuKms *gpu_kms = l->data;