[gnome-builder/wip/gtk4-port] libide/gui: add observation helpers for panes

[Christian Hergert <chergert src gnome org>]

commit 297d2b27270f2d3b3d5a5d9a62b38bfa9a2f6199
Author: Christian Hergert <chergert redhat com>
Date:   Mon Apr 18 06:08:55 2022 -0700

    libide/gui: add observation helpers for panes
    
    This can be useful so we can track panes without all the manual signal
    connection wiring. We will still use signals for that with the new
    destroyed signal on PanelWidget, but the helpers mean we are more likely
    to get the tracking right in plugins where the panels might need to be
    released or could have otherwise already been released.

 src/libide/gui/ide-pane.c | 39 +++++++++++++++++++++++++++++++++++++++
 src/libide/gui/ide-pane.h | 12 ++++++++++--
 2 files changed, 49 insertions(+), 2 deletions(-)
---
diff --git a/src/libide/gui/ide-pane.c b/src/libide/gui/ide-pane.c
index 63aabd011..6405bf321 100644
--- a/src/libide/gui/ide-pane.c
+++ b/src/libide/gui/ide-pane.c
@@ -62,3 +62,42 @@ ide_pane_destroy (IdePane *self)
   if ((frame = gtk_widget_get_ancestor (GTK_WIDGET (self), PANEL_TYPE_FRAME)))
     panel_frame_remove (PANEL_FRAME (frame), PANEL_WIDGET (self));
 }
+
+void
+ide_pane_observe (IdePane  *self,
+                  IdePane **location)
+{
+  g_return_if_fail (IDE_IS_PANE (self));
+  g_return_if_fail (location != NULL);
+
+  *location = self;
+  g_signal_connect_swapped (self,
+                            "destroyed",
+                            G_CALLBACK (g_nullify_pointer),
+                            location);
+}
+
+void
+ide_pane_unobserve (IdePane  *self,
+                    IdePane **location)
+{
+  g_return_if_fail (IDE_IS_PANE (self));
+  g_return_if_fail (location != NULL);
+
+  g_signal_handlers_disconnect_by_func (self,
+                                        G_CALLBACK (g_nullify_pointer),
+                                        location);
+  *location = NULL;
+}
+
+void
+ide_clear_pane (IdePane **location)
+{
+  IdePane *self = *location;
+
+  if (self == NULL)
+    return;
+
+  ide_pane_unobserve (self, location);
+  ide_pane_destroy (self);
+}
diff --git a/src/libide/gui/ide-pane.h b/src/libide/gui/ide-pane.h
index 7f52d5420..e2bfc09f4 100644
--- a/src/libide/gui/ide-pane.h
+++ b/src/libide/gui/ide-pane.h
@@ -41,8 +41,16 @@ struct _IdePaneClass
 };
 
 IDE_AVAILABLE_IN_ALL
-GtkWidget *ide_pane_new     (void);
+GtkWidget *ide_pane_new       (void);
 IDE_AVAILABLE_IN_ALL
-void       ide_pane_destroy (IdePane *self);
+void       ide_pane_destroy   (IdePane *self);
+IDE_AVAILABLE_IN_ALL
+void       ide_pane_observe   (IdePane  *self,
+                               IdePane **location);
+IDE_AVAILABLE_IN_ALL
+void       ide_pane_unobserve (IdePane  *self,
+                               IdePane **location);
+IDE_AVAILABLE_IN_ALL
+void       ide_clear_pane     (IdePane **location);
 
 G_END_DECLS