[gcr/wip/nielsdg/lose-x11-dependency: 1/2] prompt: Support transient_for in Wayland

[Niels De Graef <nielsdg src gnome org>]

commit aa49547f2d06fd1cafab4e23a2a8470015993fbe
Author: Niels De Graef <nielsdegraef gmail com>
Date:   Tue Dec 3 08:51:28 2019 +0100

    prompt: Support transient_for in Wayland
    
    GDK provides an interface to the _xdg-foreign_ protocol extension, which
    exactly allows to export a handle that another window can use to set
    itself transient to.

 gcr/gcr-prompt.c       |  4 +++
 ui/gcr-prompt-dialog.c | 71 +++++++++++++++++++++++++++++++++++++-------------
 2 files changed, 57 insertions(+), 18 deletions(-)
---
diff --git a/gcr/gcr-prompt.c b/gcr/gcr-prompt.c
index d1e71a4..a2a6aaf 100644
--- a/gcr/gcr-prompt.c
+++ b/gcr/gcr-prompt.c
@@ -210,6 +210,10 @@ gcr_prompt_default_init (GcrPromptIface *iface)
                 * The caller window indicates to the prompt which window is prompting the
                 * user. The prompt may choose to ignore this information or use it in whatever
                 * way it sees fit.
+                *
+                * In X11, this will be a stringified version of the XWindow handle; in
+                * Wayland this is the result of an export using the XDG foreign
+                * protocol.
                 */
                g_object_interface_install_property (iface,
                                g_param_spec_string ("caller-window", "Caller window", "Window ID of 
application window requesting prompt",
diff --git a/ui/gcr-prompt-dialog.c b/ui/gcr-prompt-dialog.c
index f623df1..9646069 100644
--- a/ui/gcr-prompt-dialog.c
+++ b/ui/gcr-prompt-dialog.c
@@ -126,14 +126,54 @@ G_DEFINE_TYPE_WITH_CODE (GcrPromptDialog, gcr_prompt_dialog, GTK_TYPE_DIALOG,
                          G_IMPLEMENT_INTERFACE (GCR_TYPE_PROMPT, gcr_prompt_dialog_prompt_iface);
 );
 
+#ifdef GDK_WINDOWING_X11
+static gboolean
+update_transient_for_x11 (GcrPromptDialog *self, GdkWindow *window)
+{
+       gint64 handle;
+       gchar *end;
+       GdkDisplay *display;
+       GdkWindow *transient_for;
+
+       handle = g_ascii_strtoll (self->pv->caller_window, &end, 10);
+       if (!end || *end != '\0') {
+               g_warning ("couldn't parse caller-window property: %s", self->pv->caller_window);
+               return FALSE;
+       }
+
+       display = gtk_widget_get_display (GTK_WIDGET (self));
+       transient_for = gdk_x11_window_foreign_new_for_display (display, (Window)handle);
+       if (transient_for == NULL) {
+               g_warning ("caller-window property doesn't represent a window on current display: %s",
+                          self->pv->caller_window);
+               return FALSE;
+
+       gdk_window_set_transient_for (window, transient_for);
+       g_object_unref (transient_for);
+       return TRUE;
+}
+#endif
+
+#ifdef GDK_WINDOWING_WAYLAND
+static gboolean
+update_transient_for_wl (GcrPromptDialog *self, GdkWindow *window)
+{
+       if (gdk_wayland_window_set_transient_for_exported (window, self->pv->caller_window)) {
+               g_debug ("Succesfully set transient for WL window %s", self->pv->caller_window);
+               return TRUE;
+       }
+
+       g_warning ("caller-window property doesn't represent a window on current display: %s",
+                  self->pv->caller_window);
+       return FALSE;
+}
+#endif
+
 static void
 update_transient_for (GcrPromptDialog *self)
 {
-       GdkDisplay *display;
-       GdkWindow *transient_for = NULL;
        GdkWindow *window;
-       gint64 handle;
-       gchar *end;
+       gboolean success = FALSE;
 
        if (self->pv->caller_window == NULL || g_str_equal (self->pv->caller_window, "")) {
                gtk_window_set_modal (GTK_WINDOW (self), FALSE);
@@ -145,22 +185,17 @@ update_transient_for (GcrPromptDialog *self)
                return;
 
 #ifdef GDK_WINDOWING_X11
-       handle = g_ascii_strtoll (self->pv->caller_window, &end, 10);
-       if (!end || *end != '\0') {
-               g_warning ("couldn't parse caller-window property: %s", self->pv->caller_window);
-               return;
-       }
+       if (!success)
+               success |= update_transient_for_x11 ();
+#endif
+#ifdef GDK_WINDOWING_WAYLAND
+       if (!success)
+               success |= update_transient_for_wl ();
+#endif
 
-       display = gtk_widget_get_display (GTK_WIDGET (self));
-       transient_for = gdk_x11_window_foreign_new_for_display (display, (Window)handle);
-       if (transient_for == NULL) {
-               g_warning ("caller-window property doesn't represent a window on current display: %s",
-                          self->pv->caller_window);
-       } else {
-               gdk_window_set_transient_for (window, transient_for);
-               g_object_unref (transient_for);
+       if (!success) {
+               g_warning ("Couldn't set transient to caller window");
        }
-#endif
 
        gtk_window_set_modal (GTK_WINDOW (self), TRUE);
 }