window: Add concept of popover "parent"

This will be the widget that the popover relates to (::pointing-to in
GtkPopover, ::parent in GtkTextHandle).

Additional API to check the popover/parent relationship between widgets
has been added, which will be useful wherever this is necessary in a
generic manner.

https://bugzilla.gnome.org/show_bug.cgi?id=750993

gtk/gtkpopover.c

@@ -1699,7 +1699,7 @@ _gtk_popover_parent_hierarchy_changed (GtkWidget  *widget,
     _gtk_window_remove_popover (priv->window, GTK_WIDGET (popover));
 
   if (new_window)
-    _gtk_window_add_popover (new_window, GTK_WIDGET (popover));
+    _gtk_window_add_popover (new_window, GTK_WIDGET (popover), priv->widget);
 
   priv->window = new_window;
 
@@ -1970,7 +1970,7 @@ gtk_popover_update_relative_to (GtkPopover *popover,
     }
 
   if (priv->window)
-    _gtk_window_add_popover (priv->window, GTK_WIDGET (popover));
+    _gtk_window_add_popover (priv->window, GTK_WIDGET (popover), priv->widget);
 
   if (relative_to)
     scrollable = GTK_SCROLLABLE (gtk_widget_get_ancestor (priv->widget, GTK_TYPE_SCROLLABLE));

gtk/gtktexthandle.c

@@ -309,7 +309,7 @@ _gtk_text_handle_ensure_widget (GtkTextHandle         *handle,
 
       priv->windows[pos].widget = g_object_ref_sink (widget);
       window = gtk_widget_get_ancestor (priv->parent, GTK_TYPE_WINDOW);
-      _gtk_window_add_popover (GTK_WINDOW (window), widget);
+      _gtk_window_add_popover (GTK_WINDOW (window), widget, priv->parent);
 
       gtk_style_context_set_parent (gtk_widget_get_style_context (widget),
                                     gtk_widget_get_style_context (priv->parent));

gtk/gtkwindow.c

@@ -132,6 +132,7 @@ typedef struct _GtkWindowPopover GtkWindowPopover;
 struct _GtkWindowPopover
 {
   GtkWidget *widget;
+  GtkWidget *parent;
   GdkWindow *window;
   GtkPositionType pos;
   cairo_rectangle_int_t rect;
@@ -11810,7 +11811,8 @@ _gtk_window_get_shadow_width (GtkWindow *window,
 
 void
 _gtk_window_add_popover (GtkWindow *window,
-                         GtkWidget *popover)
+                         GtkWidget *popover,
+                         GtkWidget *parent)
 {
   GtkWindowPrivate *priv;
   GtkWindowPopover *data;
@@ -11818,7 +11820,9 @@ _gtk_window_add_popover (GtkWindow *window,
 
   g_return_if_fail (GTK_IS_WINDOW (window));
   g_return_if_fail (GTK_IS_WIDGET (popover));
+  g_return_if_fail (GTK_IS_WIDGET (parent));
   g_return_if_fail (gtk_widget_get_parent (popover) == NULL);
+  g_return_if_fail (gtk_widget_is_ancestor (parent, GTK_WIDGET (window)));
 
   priv = window->priv;
 
@@ -11827,6 +11831,7 @@ _gtk_window_add_popover (GtkWindow *window,
 
   data = g_new0 (GtkWindowPopover, 1);
   data->widget = popover;
+  data->parent = parent;
   priv->popovers = g_list_prepend (priv->popovers, data);
 
   if (gtk_widget_get_realized (GTK_WIDGET (window)))
@@ -11943,6 +11948,52 @@ _gtk_window_get_popover_position (GtkWindow             *window,
     *rect = data->rect;
 }
 
+/*<private>
+ * _gtk_window_get_popover_parent:
+ * @window: A #GtkWindow
+ * @popover: A popover #GtkWidget
+ *
+ * Returns the conceptual parent of this popover, the real
+ * parent will always be @window.
+ *
+ * Returns: The conceptual parent widget, or %NULL.
+ **/
+GtkWidget *
+_gtk_window_get_popover_parent (GtkWindow *window,
+                                GtkWidget *popover)
+{
+  GtkWindowPopover *data;
+
+  g_return_if_fail (GTK_IS_WINDOW (window));
+  g_return_if_fail (GTK_IS_WIDGET (popover));
+
+  data = _gtk_window_has_popover (window, popover);
+
+  if (data && data->parent)
+    return data->parent;
+
+  return NULL;
+}
+
+/*<private>
+ * _gtk_window_is_popover_widget:
+ * @window: A #GtkWindow
+ * @possible_popover: A possible popover of @window
+ *
+ * Returns #TRUE if @possible_popover is a popover of @window.
+ *
+ * Returns: Whether the widget is a popover of @window
+ **/
+gboolean
+_gtk_window_is_popover_widget (GtkWindow *window,
+                               GtkWidget *possible_popover)
+{
+  g_return_val_if_fail (GTK_IS_WINDOW (window), FALSE);
+  g_return_val_if_fail (GTK_IS_WIDGET (possible_popover), FALSE);
+
+  return _gtk_window_has_popover (window, possible_popover) != NULL;
+}
+
 static GtkWidget *inspector_window = NULL;
 
 static void set_warn_again (gboolean warn);

gtk/gtkwindowprivate.h

@@ -104,7 +104,8 @@ void            _gtk_window_set_window_group (GtkWindow      *window,
 
 /* Popovers */
 void    _gtk_window_add_popover          (GtkWindow                   *window,
-                                          GtkWidget                   *popover);
+                                          GtkWidget                   *popover,
+                                          GtkWidget                   *popover_parent);
 void    _gtk_window_remove_popover       (GtkWindow                   *window,
                                           GtkWidget                   *popover);
 void    _gtk_window_set_popover_position (GtkWindow                   *window,
@@ -116,6 +117,11 @@ void    _gtk_window_get_popover_position (GtkWindow                   *window,
                                           GtkPositionType             *pos,
                                           cairo_rectangle_int_t       *rect);
 
+GtkWidget * _gtk_window_get_popover_parent (GtkWindow *window,
+                                            GtkWidget *popover);
+gboolean    _gtk_window_is_popover_widget  (GtkWindow *window,
+                                            GtkWidget *popover);
+
 GdkPixbuf *gtk_window_get_icon_for_size (GtkWindow *window,
                                          gint       size);