[tepl] AppWindow: add get_window_group()

[Sébastien Wilmet <swilmet src gnome org>]

commit 316e75f1c967065d35c8f5fab60c30ea26f17c47
Author: Sébastien Wilmet <swilmet gnome org>
Date:   Sat Oct 14 14:55:24 2017 +0200

    AppWindow: add get_window_group()
    
    Like in GeditWindow.

 docs/reference/tepl-3.0-sections.txt |    1 +
 tepl/tepl-application-window.c       |   49 ++++++++++++++++++++++++++++++++++
 tepl/tepl-application-window.h       |    2 +
 3 files changed, 52 insertions(+), 0 deletions(-)
---
diff --git a/docs/reference/tepl-3.0-sections.txt b/docs/reference/tepl-3.0-sections.txt
index 64d1162..f51104b 100644
--- a/docs/reference/tepl-3.0-sections.txt
+++ b/docs/reference/tepl-3.0-sections.txt
@@ -219,6 +219,7 @@ tepl_application_window_get_from_gtk_application_window
 tepl_application_window_get_application_window
 tepl_application_window_set_tab_group
 tepl_application_window_is_main_window
+tepl_application_window_get_window_group
 tepl_application_window_get_handle_title
 tepl_application_window_set_handle_title
 tepl_application_window_open_file
diff --git a/tepl/tepl-application-window.c b/tepl/tepl-application-window.c
index 3c0b0fb..eebf7a2 100644
--- a/tepl/tepl-application-window.c
+++ b/tepl/tepl-application-window.c
@@ -86,6 +86,9 @@
 struct _TeplApplicationWindowPrivate
 {
        GtkApplicationWindow *gtk_window;
+
+       GtkWindowGroup *window_group;
+
        TeplTabGroup *tab_group;
        TeplSignalGroup *view_signal_group;
        TeplSignalGroup *buffer_signal_group;
@@ -932,6 +935,9 @@ tepl_application_window_dispose (GObject *object)
        TeplApplicationWindow *tepl_window = TEPL_APPLICATION_WINDOW (object);
 
        tepl_window->priv->gtk_window = NULL;
+
+       g_clear_object (&tepl_window->priv->window_group);
+
        g_clear_object (&tepl_window->priv->tab_group);
        _tepl_signal_group_clear (&tepl_window->priv->view_signal_group);
        _tepl_signal_group_clear (&tepl_window->priv->buffer_signal_group);
@@ -1361,6 +1367,49 @@ tepl_application_window_is_main_window (GtkApplicationWindow *gtk_window)
 }
 
 /**
+ * tepl_application_window_get_window_group:
+ * @tepl_window: a #TeplApplicationWindow.
+ *
+ * Gets the #GtkWindowGroup in which @tepl_window resides.
+ *
+ * You should call this function only on main windows, to add secondary windows
+ * to the #GtkWindowGroup.
+ *
+ * Returns: (transfer none): the #GtkWindowGroup.
+ * Since: 3.2
+ */
+GtkWindowGroup *
+tepl_application_window_get_window_group (TeplApplicationWindow *tepl_window)
+{
+       g_return_val_if_fail (TEPL_IS_APPLICATION_WINDOW (tepl_window), NULL);
+
+       /* Lazy init.
+        *
+        * If the GtkWindowGroup was created in constructed() instead, this can
+        * be dangerous because the mere fact of calling
+        * tepl_application_window_get_from_gtk_application_window() would add
+        * the window to a different GtkWindowGroup. If for one reason or
+        * another the TeplApplicationWindow object is created for a secondary
+        * window, it should not cause problems.
+        *
+        * It is not a problem if a main window is still part of the default
+        * window group (i.e. if this function has never been called on that
+        * main window). For example when creating a modal dialog, this function
+        * will be called on the corresponding main window, and it'll still be
+        * possible to interact with the other main windows that are part of the
+        * default window group.
+        */
+       if (tepl_window->priv->window_group == NULL)
+       {
+               tepl_window->priv->window_group = gtk_window_group_new ();
+               gtk_window_group_add_window (tepl_window->priv->window_group,
+                                            GTK_WINDOW (tepl_window->priv->gtk_window));
+       }
+
+       return tepl_window->priv->window_group;
+}
+
+/**
  * tepl_application_window_get_handle_title:
  * @tepl_window: a #TeplApplicationWindow.
  *
diff --git a/tepl/tepl-application-window.h b/tepl/tepl-application-window.h
index 76e4280..be5231f 100644
--- a/tepl/tepl-application-window.h
+++ b/tepl/tepl-application-window.h
@@ -64,6 +64,8 @@ void                  tepl_application_window_set_tab_group                   
(TeplApplicationWindow *tepl_wind
 
 gboolean               tepl_application_window_is_main_window                  (GtkApplicationWindow 
*gtk_window);
 
+GtkWindowGroup *       tepl_application_window_get_window_group                (TeplApplicationWindow 
*tepl_window);
+
 gboolean               tepl_application_window_get_handle_title                (TeplApplicationWindow 
*tepl_window);
 
 void                   tepl_application_window_set_handle_title                (TeplApplicationWindow 
*tepl_window,