wayland: Implement the XDG dialog protocol

This protocol takes over some of our homegrown GTK Shell
protocol, allowing to specify hints on surfaces such as
dialog modality.

Part-of: <https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/3557>

meson.build

@@ -46,7 +46,7 @@ gudev_req = '>= 232'
 
 # wayland version requirements
 wayland_server_req = '>= 1.22'
-wayland_protocols_req = '>= 1.33'
+wayland_protocols_req = '>= 1.36'
 
 # native backend version requirements
 libinput_req = '>= 1.19.0'

src/meson.build

@@ -702,6 +702,8 @@ if have_wayland
     'wayland/meta-wayland-xdg-foreign-private.h',
     'wayland/meta-wayland-xdg-shell.c',
     'wayland/meta-wayland-xdg-shell.h',
+    'wayland/meta-wayland-xdg-dialog.c',
+    'wayland/meta-wayland-xdg-dialog.h',
     'wayland/meta-window-wayland.c',
     'wayland/meta-window-wayland.h',
   ]
@@ -1077,6 +1079,7 @@ if have_wayland
     ['text-input', 'unstable', 'v3', ],
     ['viewporter', 'stable', ],
     ['xdg-activation', 'staging', 'v1', ],
+    ['xdg-dialog', 'staging', 'v1', ],
     ['xdg-foreign', 'unstable', 'v1', ],
     ['xdg-foreign', 'unstable', 'v2', ],
     ['xdg-output', 'unstable', 'v1', ],

src/wayland/meta-wayland-versions.h

@@ -57,3 +57,4 @@
 #define META_WP_SINGLE_PIXEL_BUFFER_V1_VERSION 1
 #define META_MUTTER_X11_INTEROP_VERSION 1
 #define META_WP_FRACTIONAL_SCALE_VERSION 1
+#define META_XDG_DIALOG_VERSION 1

src/wayland/meta-wayland-xdg-dialog.c

@@ -0,0 +1,233 @@
+/*
+ * Wayland Support
+ *
+ * Copyright (C) 2024 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, see <http://www.gnu.org/licenses/>.
+ *
+ * Author: Carlos Garnacho <carlosg@gnome.org>
+ */
+
+#include "config.h"
+
+#include "wayland/meta-wayland-xdg-dialog.h"
+
+#include "core/window-private.h"
+#include "wayland/meta-wayland-private.h"
+#include "wayland/meta-wayland-xdg-shell.h"
+#include "wayland/meta-wayland-versions.h"
+
+#include "xdg-dialog-v1-server-protocol.h"
+
+static GQuark quark_xdg_dialog_data = 0;
+
+typedef struct _MetaWaylandXdgDialog
+{
+  struct wl_resource *resource;
+  MetaWaylandXdgSurface *toplevel;
+  gboolean is_modal;
+} MetaWaylandXdgDialog;
+
+struct _MetaWaylandXdgWmDialog
+{
+  GObject parent;
+  struct wl_list resources;
+};
+
+#define META_TYPE_WAYLAND_XDG_WM_DIALOG (meta_wayland_xdg_wm_dialog_get_type ())
+G_DECLARE_FINAL_TYPE (MetaWaylandXdgWmDialog, meta_wayland_xdg_wm_dialog,
+                      META, WAYLAND_XDG_WM_DIALOG, GObject)
+
+G_DEFINE_TYPE (MetaWaylandXdgWmDialog, meta_wayland_xdg_wm_dialog, G_TYPE_OBJECT)
+
+static void
+xdg_dialog_destructor (struct wl_resource *resource)
+{
+  MetaWaylandXdgDialog *xdg_dialog = wl_resource_get_user_data (resource);
+
+  if (xdg_dialog->toplevel)
+    {
+      g_object_steal_qdata (G_OBJECT (xdg_dialog->toplevel),
+                            quark_xdg_dialog_data);
+    }
+
+  g_free (xdg_dialog);
+}
+
+static void
+xdg_dialog_set_modal (struct wl_client   *client,
+                      struct wl_resource *resource)
+{
+  MetaWaylandXdgDialog *xdg_dialog = wl_resource_get_user_data (resource);
+  MetaWaylandXdgSurface *xdg_surface;
+
+  xdg_surface = xdg_dialog->toplevel;
+
+  if (xdg_surface && !xdg_dialog->is_modal)
+    {
+      MetaWaylandSurfaceRole *surface_role =
+        META_WAYLAND_SURFACE_ROLE (xdg_surface);
+      MetaWaylandSurface *surface =
+        meta_wayland_surface_role_get_surface (surface_role);
+      MetaWindow *window = meta_wayland_surface_get_window (surface);
+
+      xdg_dialog->is_modal = TRUE;
+      meta_window_set_type (window, META_WINDOW_MODAL_DIALOG);
+    }
+}
+
+static void
+xdg_dialog_unset_modal (struct wl_client   *client,
+                        struct wl_resource *resource)
+{
+  MetaWaylandXdgDialog *xdg_dialog = wl_resource_get_user_data (resource);
+  MetaWaylandXdgSurface *xdg_surface;
+
+  xdg_surface = xdg_dialog->toplevel;
+
+  if (xdg_surface && xdg_dialog->is_modal)
+    {
+      MetaWaylandSurfaceRole *surface_role =
+        META_WAYLAND_SURFACE_ROLE (xdg_surface);
+      MetaWaylandSurface *surface =
+        meta_wayland_surface_role_get_surface (surface_role);
+      MetaWindow *window = meta_wayland_surface_get_window (surface);
+
+      xdg_dialog->is_modal = FALSE;
+      meta_window_set_type (window, META_WINDOW_NORMAL);
+    }
+}
+
+static void
+xdg_dialog_destroy (struct wl_client   *client,
+                    struct wl_resource *resource)
+{
+  wl_resource_destroy (resource);
+}
+
+static const struct xdg_dialog_v1_interface meta_wayland_xdg_dialog_interface = {
+  xdg_dialog_destroy,
+  xdg_dialog_set_modal,
+  xdg_dialog_unset_modal,
+};
+
+static void
+xdg_dialog_toplevel_destroyed (MetaWaylandXdgDialog *xdg_dialog)
+{
+  xdg_dialog->toplevel = NULL;
+}
+
+static void
+xdg_wm_dialog_destroy (struct wl_client   *client,
+                       struct wl_resource *resource)
+{
+  wl_resource_destroy (resource);
+}
+
+static void
+xdg_wm_dialog_get_xdg_dialog (struct wl_client   *client,
+                              struct wl_resource *resource,
+                              uint32_t            id,
+                              struct wl_resource *toplevel_resource)
+{
+  MetaWaylandXdgSurface *xdg_surface = wl_resource_get_user_data (toplevel_resource);
+  MetaWaylandXdgDialog *xdg_dialog;
+
+  xdg_dialog = g_object_get_qdata (G_OBJECT (xdg_surface), quark_xdg_dialog_data);
+  if (xdg_dialog)
+    {
+      wl_resource_post_error (toplevel_resource,
+                              XDG_WM_DIALOG_V1_ERROR_ALREADY_USED,
+                              "xdg_wm_dialog_v1::get_xdg_dialog already requested");
+      return;
+    }
+
+  xdg_dialog = g_new0 (MetaWaylandXdgDialog, 1);
+  xdg_dialog->toplevel = xdg_surface;
+  xdg_dialog->resource = wl_resource_create (client,
+                                             &xdg_dialog_v1_interface,
+                                             wl_resource_get_version (resource),
+                                             id);
+  wl_resource_set_implementation (xdg_dialog->resource,
+                                  &meta_wayland_xdg_dialog_interface,
+                                  xdg_dialog, xdg_dialog_destructor);
+
+  g_object_set_qdata_full (G_OBJECT (xdg_surface),
+                           quark_xdg_dialog_data,
+                           xdg_dialog,
+                           (GDestroyNotify) xdg_dialog_toplevel_destroyed);
+}
+
+static const struct xdg_wm_dialog_v1_interface meta_wayland_xdg_wm_dialog_interface = {
+  xdg_wm_dialog_destroy,
+  xdg_wm_dialog_get_xdg_dialog,
+};
+
+static void
+unbind_resource (struct wl_resource *resource)
+{
+  wl_list_remove (wl_resource_get_link (resource));
+}
+
+static void
+bind_xdg_wm_dialog (struct wl_client *client,
+                    void             *data,
+                    uint32_t          version,
+                    uint32_t          id)
+{
+  MetaWaylandXdgWmDialog *xdg_wm_dialog = data;
+  struct wl_resource *resource;
+
+  resource = wl_resource_create (client, &xdg_wm_dialog_v1_interface, version, id);
+  wl_resource_set_implementation (resource, &meta_wayland_xdg_wm_dialog_interface,
+                                  data, unbind_resource);
+  wl_list_insert (&xdg_wm_dialog->resources, wl_resource_get_link (resource));
+}
+
+static void
+meta_wayland_xdg_wm_dialog_init (MetaWaylandXdgWmDialog *xdg_wm_dialog)
+{
+  wl_list_init (&xdg_wm_dialog->resources);
+}
+
+static void
+meta_wayland_xdg_wm_dialog_class_init (MetaWaylandXdgWmDialogClass *klass)
+{
+  quark_xdg_dialog_data =
+    g_quark_from_static_string ("-meta-wayland-xdg-wm-dialog-surface-data");
+}
+
+static MetaWaylandXdgWmDialog *
+meta_wayland_xdg_wm_dialog_new (MetaWaylandCompositor *compositor)
+{
+  MetaWaylandXdgWmDialog *xdg_wm_dialog;
+
+  xdg_wm_dialog = g_object_new (META_TYPE_WAYLAND_XDG_WM_DIALOG, NULL);
+
+  if (wl_global_create (compositor->wayland_display,
+                        &xdg_wm_dialog_v1_interface,
+                        META_XDG_DIALOG_VERSION,
+                        xdg_wm_dialog, bind_xdg_wm_dialog) == NULL)
+    g_error ("Failed to register a global xdg-dialog object");
+
+  return xdg_wm_dialog;
+}
+
+void
+meta_wayland_init_xdg_wm_dialog (MetaWaylandCompositor *compositor)
+{
+  g_object_set_data_full (G_OBJECT (compositor), "-meta-wayland-xdg-wm-dialog",
+                          meta_wayland_xdg_wm_dialog_new (compositor),
+                          g_object_unref);
+}

src/wayland/meta-wayland-xdg-dialog.h

@@ -0,0 +1,22 @@
+/*
+ * Copyright (C) 2016 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, see <http://www.gnu.org/licenses/>.
+ */
+
+#pragma once
+
+#include "wayland/meta-wayland.h"
+
+void meta_wayland_init_xdg_wm_dialog (MetaWaylandCompositor *compositor);

src/wayland/meta-wayland.c

@@ -56,6 +56,7 @@
 #include "wayland/meta-wayland-subsurface.h"
 #include "wayland/meta-wayland-tablet-manager.h"
 #include "wayland/meta-wayland-transaction.h"
+#include "wayland/meta-wayland-xdg-dialog.h"
 #include "wayland/meta-wayland-xdg-foreign.h"
 #include "wayland/meta-wayland-linux-drm-syncobj.h"
 
@@ -870,6 +871,7 @@ meta_wayland_compositor_new (MetaContext *context)
   meta_wayland_transaction_init (compositor);
   meta_wayland_idle_inhibit_init (compositor);
   meta_wayland_drm_syncobj_init (compositor);
+  meta_wayland_init_xdg_wm_dialog (compositor);
 
 #ifdef HAVE_WAYLAND_EGLSTREAM
   {