cogl: Add CoglX11Onscreen interface

Mutter needs to fetch the X11 Window ID from the onscreen and did that
by using an X11 specific API on the CoglOnscreen, where the X11 type was
"expanded" (Window -> uint32_t). Change this by introducing an interface
called CoglX11Onscreen, implemented by both the Xlib and GLX onscreen
implementations, that keeps the right type (Window), while avoiding X11
specific API for CoglOnscreen.

Part-of: <https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1514>

cogl/cogl/cogl-mutter.h

@@ -48,6 +48,9 @@
 #if defined (COGL_HAS_XLIB_SUPPORT)
 #include <cogl/winsys/cogl-onscreen-xlib.h>
 #endif
+#ifdef COGL_HAS_X11
+#include <cogl/cogl-x11-onscreen.h>
+#endif
 #include <cogl/winsys/cogl-winsys-private.h>
 
 COGL_EXPORT

cogl/cogl/cogl-onscreen.c

@@ -498,20 +498,6 @@ cogl_onscreen_pop_head_frame_info (CoglOnscreen *onscreen)
   return g_queue_pop_head (&priv->pending_frame_infos);
 }
 
-#ifdef COGL_HAS_X11_SUPPORT
-uint32_t
-cogl_x11_onscreen_get_window_xid (CoglOnscreen *onscreen)
-{
-  CoglFramebuffer *framebuffer = COGL_FRAMEBUFFER (onscreen);
-  const CoglWinsysVtable *winsys = _cogl_framebuffer_get_winsys (framebuffer);
-
-  /* This should only be called for x11 onscreens */
-  g_return_val_if_fail (winsys->onscreen_x11_get_window_xid != NULL, 0);
-
-  return winsys->onscreen_x11_get_window_xid (onscreen);
-}
-#endif /* COGL_HAS_X11_SUPPORT */
-
 CoglFrameClosure *
 cogl_onscreen_add_frame_callback (CoglOnscreen *onscreen,
                                   CoglFrameCallback callback,

cogl/cogl/cogl-onscreen.h

@@ -90,29 +90,6 @@ typedef enum _CoglScanoutError
   COGL_SCANOUT_ERROR_INHIBITED,
 } CoglScanoutError;
 
-#ifdef COGL_HAS_X11
-/**
- * cogl_x11_onscreen_get_window_xid:
- * @onscreen: A #CoglOnscreen framebuffer
- *
- * Assuming you know the given @onscreen framebuffer is based on an x11 window
- * this queries the XID of that window. If
- * cogl_x11_onscreen_set_foreign_window_xid() was previously called then it
- * will return that same XID otherwise it will be the XID of a window Cogl
- * created internally. If the window has not been allocated yet and a foreign
- * xid has not been set then it's undefined what value will be returned.
- *
- * It's undefined what this function does if called when not using an x11 based
- * renderer.
- *
- * Since: 1.10
- * Stability: unstable
- */
-COGL_EXPORT uint32_t
-cogl_x11_onscreen_get_window_xid (CoglOnscreen *onscreen);
-
-#endif /* COGL_HAS_X11 */
-
 /**
  * cogl_onscreen_show:
  * @onscreen: The onscreen framebuffer to make visible

cogl/cogl/cogl-x11-onscreen.c

@@ -0,0 +1,40 @@
+/*
+ * Copyright (C) 2020 Red Hat Inc.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; either version 2 of the
+ * License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
+ * 02111-1307, USA.
+ *
+ */
+
+#include "cogl-config.h"
+
+#include "cogl-x11-onscreen.h"
+
+G_DEFINE_INTERFACE (CoglX11Onscreen, cogl_x11_onscreen,
+                    G_TYPE_OBJECT)
+
+Window
+cogl_x11_onscreen_get_x11_window (CoglX11Onscreen *x11_onscreen)
+{
+  CoglX11OnscreenInterface *iface =
+    COGL_X11_ONSCREEN_GET_IFACE (x11_onscreen);
+
+  return iface->get_x11_window (x11_onscreen);
+}
+
+static void
+cogl_x11_onscreen_default_init (CoglX11OnscreenInterface *iface)
+{
+}

cogl/cogl/cogl-x11-onscreen.h

@@ -0,0 +1,49 @@
+/*
+ * Copyright (C) 2020 Red Hat Inc.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; either version 2 of the
+ * License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
+ * 02111-1307, USA.
+ *
+ */
+
+#if !defined(__COGL_H_INSIDE__) && !defined(COGL_COMPILATION)
+#error "Only <cogl/cogl.h> can be included directly."
+#endif
+
+#ifndef COGL_X11_ONSCREEN_H
+#define COGL_X11_ONSCREEN_H
+
+#include <glib-object.h>
+#include <X11/Xlib.h>
+
+#include "cogl-macros.h"
+
+#define COGL_TYPE_X11_ONSCREEN (cogl_x11_onscreen_get_type ())
+COGL_EXPORT
+G_DECLARE_INTERFACE (CoglX11Onscreen, cogl_x11_onscreen,
+                     COGL, X11_ONSCREEN,
+                     GObject)
+
+struct _CoglX11OnscreenInterface
+{
+  GTypeInterface parent_iface;
+
+  Window (* get_x11_window) (CoglX11Onscreen *x11_onscreen);
+};
+
+COGL_EXPORT
+Window cogl_x11_onscreen_get_x11_window (CoglX11Onscreen *x11_onscreen);
+
+#endif /* COGL_X11_ONSCREEN_H */

cogl/cogl/meson.build

@@ -371,6 +371,8 @@ if have_x11
     'cogl-xlib.h',
   ]
   cogl_sources += [
+    'cogl-x11-onscreen.c',
+    'cogl-x11-onscreen.h',
     'cogl-x11-renderer-private.h',
     'cogl-xlib-private.h',
     'cogl-xlib-renderer-private.h',

cogl/cogl/winsys/cogl-onscreen-glx.c

@@ -33,6 +33,7 @@
 #include "cogl-context-private.h"
 #include "cogl-frame-info-private.h"
 #include "cogl-renderer-private.h"
+#include "cogl-x11-onscreen.h"
 #include "cogl-xlib-renderer-private.h"
 #include "winsys/cogl-glx-display-private.h"
 #include "winsys/cogl-glx-renderer-private.h"
@@ -52,8 +53,13 @@ struct _CoglOnscreenGlx
   uint32_t pending_complete_notify;
 };
 
-G_DEFINE_TYPE (CoglOnscreenGlx, cogl_onscreen_glx,
+static void
-               COGL_TYPE_ONSCREEN)
+x11_onscreen_init_iface (CoglX11OnscreenInterface *iface);
+
+G_DEFINE_TYPE_WITH_CODE (CoglOnscreenGlx, cogl_onscreen_glx,
+                         COGL_TYPE_ONSCREEN,
+                         G_IMPLEMENT_INTERFACE (COGL_TYPE_X11_ONSCREEN,
+                                                x11_onscreen_init_iface))
 
 #define COGL_ONSCREEN_X11_EVENT_MASK (StructureNotifyMask | ExposureMask)
 
@@ -942,10 +948,10 @@ cogl_onscreen_glx_swap_buffers_with_damage (CoglOnscreen  *onscreen,
   set_frame_info_output (onscreen, onscreen_glx->output);
 }
 
-uint32_t
+static Window
-_cogl_winsys_onscreen_glx_get_window_xid (CoglOnscreen *onscreen)
+cogl_onscreen_glx_get_x11_window (CoglX11Onscreen *x11_onscreen)
 {
-  CoglOnscreenGlx *onscreen_glx = COGL_ONSCREEN_GLX (onscreen);
+  CoglOnscreenGlx *onscreen_glx = COGL_ONSCREEN_GLX (x11_onscreen);
 
   return onscreen_glx->xwin;
 }
@@ -1085,6 +1091,12 @@ cogl_onscreen_glx_init (CoglOnscreenGlx *onscreen_glx)
 {
 }
 
+static void
+x11_onscreen_init_iface (CoglX11OnscreenInterface *iface)
+{
+  iface->get_x11_window = cogl_onscreen_glx_get_x11_window;
+}
+
 static void
 cogl_onscreen_glx_class_init (CoglOnscreenGlxClass *klass)
 {

cogl/cogl/winsys/cogl-onscreen-glx.h

@@ -44,9 +44,6 @@ cogl_onscreen_glx_new (CoglContext *context,
 int
 _cogl_winsys_onscreen_glx_get_buffer_age (CoglOnscreen *onscreen);
 
-uint32_t
-_cogl_winsys_onscreen_glx_get_window_xid (CoglOnscreen *onscreen);
-
 void
 cogl_onscreen_glx_resize (CoglOnscreen    *onscreen,
                           XConfigureEvent *configure_event);

cogl/cogl/winsys/cogl-onscreen-xlib.c

@@ -30,6 +30,7 @@
 
 #include "cogl-context-private.h"
 #include "cogl-renderer-private.h"
+#include "cogl-x11-onscreen.h"
 #include "cogl-xlib-renderer-private.h"
 #include "winsys/cogl-onscreen-egl.h"
 #include "winsys/cogl-winsys-egl-x11-private.h"
@@ -41,8 +42,13 @@ struct _CoglOnscreenXlib
   Window xwin;
 };
 
-G_DEFINE_TYPE (CoglOnscreenXlib, cogl_onscreen_xlib,
+static void
-               COGL_TYPE_ONSCREEN_EGL)
+x11_onscreen_init_iface (CoglX11OnscreenInterface *iface);
+
+G_DEFINE_TYPE_WITH_CODE (CoglOnscreenXlib, cogl_onscreen_xlib,
+                         COGL_TYPE_ONSCREEN_EGL,
+                         G_IMPLEMENT_INTERFACE (COGL_TYPE_X11_ONSCREEN,
+                                                x11_onscreen_init_iface))
 
 #define COGL_ONSCREEN_X11_EVENT_MASK (StructureNotifyMask | ExposureMask)
 
@@ -194,10 +200,10 @@ cogl_onscreen_xlib_dispose (GObject *object)
     }
 }
 
-uint32_t
+static Window
-_cogl_winsys_onscreen_xlib_get_window_xid (CoglOnscreen *onscreen)
+cogl_onscreen_xlib_get_x11_window (CoglX11Onscreen *x11_onscreen)
 {
-  CoglOnscreenXlib *onscreen_xlib = COGL_ONSCREEN_XLIB (onscreen);
+  CoglOnscreenXlib *onscreen_xlib = COGL_ONSCREEN_XLIB (x11_onscreen);
 
   return onscreen_xlib->xwin;
 }
@@ -244,6 +250,12 @@ cogl_onscreen_xlib_init (CoglOnscreenXlib *onscreen_xlib)
 {
 }
 
+static void
+x11_onscreen_init_iface (CoglX11OnscreenInterface *iface)
+{
+  iface->get_x11_window = cogl_onscreen_xlib_get_x11_window;
+}
+
 static void
 cogl_onscreen_xlib_class_init (CoglOnscreenXlibClass *klass)
 {

cogl/cogl/winsys/cogl-onscreen-xlib.h

@@ -49,9 +49,6 @@ cogl_onscreen_xlib_new (CoglContext *context,
 void
 _cogl_winsys_egl_onscreen_xlib_deinit (CoglOnscreen *onscreen);
 
-uint32_t
-_cogl_winsys_onscreen_xlib_get_window_xid (CoglOnscreen *onscreen);
-
 gboolean
 cogl_onscreen_xlib_is_for_window (CoglOnscreen *onscreen,
                                   Window        window);

cogl/cogl/winsys/cogl-winsys-egl-x11.c

@@ -590,9 +590,6 @@ _cogl_winsys_egl_xlib_get_vtable (void)
       vtable.renderer_connect = _cogl_winsys_renderer_connect;
       vtable.renderer_disconnect = _cogl_winsys_renderer_disconnect;
 
-      vtable.onscreen_x11_get_window_xid =
-        _cogl_winsys_onscreen_xlib_get_window_xid;
-
 #ifdef EGL_KHR_image_pixmap
       /* X11 tfp support... */
       /* XXX: instead of having a rather monolithic winsys vtable we could

cogl/cogl/winsys/cogl-winsys-glx.c

@@ -1470,8 +1470,6 @@ static CoglWinsysVtable _cogl_winsys_vtable =
     .context_deinit = _cogl_winsys_context_deinit,
     .context_get_clock_time = _cogl_winsys_get_clock_time,
     .onscreen_get_buffer_age = _cogl_winsys_onscreen_glx_get_buffer_age,
-    .onscreen_x11_get_window_xid =
-      _cogl_winsys_onscreen_glx_get_window_xid,
 
     /* X11 tfp support... */
     /* XXX: instead of having a rather monolithic winsys vtable we could

cogl/cogl/winsys/cogl-winsys-private.h

@@ -112,9 +112,6 @@ typedef struct _CoglWinsysVtable
   int
   (*onscreen_get_buffer_age) (CoglOnscreen *onscreen);
 
-  uint32_t
-  (*onscreen_x11_get_window_xid) (CoglOnscreen *onscreen);
-
 #ifdef COGL_HAS_XLIB_SUPPORT
   gboolean
   (*texture_pixmap_x11_create) (CoglTexturePixmapX11 *tex_pixmap);

src/backends/x11/meta-stage-x11.c

@@ -330,7 +330,8 @@ meta_stage_x11_realize (ClutterStageWindow *stage_window)
   if (!(clutter_stage_window_parent_iface->realize (stage_window)))
     return FALSE;
 
-  stage_x11->xwin = cogl_x11_onscreen_get_window_xid (stage_x11->onscreen);
+  stage_x11->xwin =
+    cogl_x11_onscreen_get_x11_window (COGL_X11_ONSCREEN (stage_x11->onscreen));
 
   if (clutter_stages_by_xid == NULL)
     clutter_stages_by_xid = g_hash_table_new (NULL, NULL);