[dia] Object add/remove signaled only once per diagram change

[Hans Breuer <hans src gnome org>]

commit 2adebd449b21579f6666a8159206f3bd0f42fc8c
Author: Hans Breuer <hans breuer org>
Date:   Fri Jun 12 16:44:33 2009 +0200

    Object add/remove signaled only once per diagram change

 app/diagram.c |    2 +-
 app/undo.c    |   20 ++++++++------------
 lib/layer.c   |   19 +++++++++++++------
 3 files changed, 22 insertions(+), 19 deletions(-)
---
diff --git a/app/diagram.c b/app/diagram.c
index c05d064..b60c0e4 100644
--- a/app/diagram.c
+++ b/app/diagram.c
@@ -743,7 +743,7 @@ diagram_selected_break_external(Diagram *dia)
 	connected_list = g_list_next(connected_list);
       }
     }
-    data_emit (dia->data, dia_object_get_parent_layer(obj), obj, "object_remove");
+
     list = g_list_next(list);
   }
 }
diff --git a/app/undo.c b/app/undo.c
index 88f81cc..9a3d634 100644
--- a/app/undo.c
+++ b/app/undo.c
@@ -658,18 +658,14 @@ delete_objects_revert(struct DeleteObjectsChange *change, Diagram *dia)
 			g_list_copy(change->original_objects));
   object_add_updates_list(change->obj_list, dia);
 
- list = change->obj_list;
- while (list)
- {
-   DiaObject *obj = (DiaObject *) list->data;
-   if (obj->parent) /* Restore child references */
-   	obj->parent->children = g_list_append(obj->parent->children, obj);
-   	
-   /* Emit a signal per object reverted */
-   data_emit(layer_get_parent_diagram(change->layer),change->layer,obj,"object_add");
-
-  list = g_list_next(list);
- }
+  list = change->obj_list;
+  while (list) {
+    DiaObject *obj = (DiaObject *) list->data;
+    if (obj->parent) /* Restore child references */
+      obj->parent->children = g_list_append(obj->parent->children, obj);
+    /* no need to emit object_add signal, already done by layer_set_object_list */
+    list = g_list_next(list);
+  }
 }
 
 static void
diff --git a/lib/layer.c b/lib/layer.c
index d78f2ea..c5dd131 100644
--- a/lib/layer.c
+++ b/lib/layer.c
@@ -255,13 +255,14 @@ layer_remove_objects(Layer *layer, GList *obj_list)
   while (obj_list != NULL) {
     obj = (DiaObject *) obj_list->data;
     
+    /* send a signal that we will remove an object from the diagram */
+    data_emit (layer_get_parent_diagram(layer), layer, obj, "object_remove");
+
     layer->objects = g_list_remove(layer->objects, obj);
     
     obj_list = g_list_next(obj_list);
     dynobj_list_remove_object(obj);
     set_parent_layer(obj, NULL);
-    /* send a signal that we have removed a object from the diagram */
-    data_emit (layer_get_parent_diagram(layer), layer, obj, "object_remove");
   }
 }
 
@@ -537,26 +538,32 @@ layer_remove_dynobj(gpointer obj, gpointer userdata)
   dynobj_list_remove_object((DiaObject*)obj);
 }
 
-void layer_set_object_list(Layer *layer, GList *list)
+void 
+layer_set_object_list(Layer *layer, GList *list)
 {
   GList *ol;
   /* signal removal on all objects */
   ol = layer->objects;
   while (ol) {
-    data_emit (layer_get_parent_diagram(layer), layer, ol->data, "object_remove");
+    if (!g_list_find (list, ol->data)) /* only if it really vanishes */
+      data_emit (layer_get_parent_diagram(layer), layer, ol->data, "object_remove");
     ol = g_list_next (ol);
   }
+  /* restore old list */
+  ol = layer->objects;
   g_list_foreach(layer->objects, set_parent_layer, NULL);
   g_list_foreach(layer->objects, layer_remove_dynobj, NULL);
-  g_list_free(layer->objects);
+
   layer->objects = list;
   g_list_foreach(layer->objects, set_parent_layer, layer);
   /* signal addition on all objects */
   list = layer->objects;
   while (list) {
-    data_emit (layer_get_parent_diagram(layer), layer, list->data, "object_add");
+    if (!g_list_find (ol, list->data)) /* only if it is new */
+      data_emit (layer_get_parent_diagram(layer), layer, list->data, "object_add");
     list = g_list_next (list);
   }
+  g_list_free(ol);
 }
 
 DiagramData *