app: reload GEGL operation with version management appropriately.

We are adding the infrastructure in both GEGL and GIMP to be able to
reload the expected rendering of a filter while still allowing updating
its arguments.
For this to work, a GEGL operation will have to keep code path for older
versions.

app/tools/gimpfiltertool.c

@@ -1167,6 +1167,7 @@ gimp_filter_tool_commit (GimpFilterTool *filter_tool,
       region          = gimp_drawable_filter_get_region (filter_tool->filter);
 
       existing_node = gimp_drawable_filter_get_operation (filter_tool->existing_filter);
+      gegl_node_set_op_version (existing_node, NULL);
       gegl_node_get (existing_node,
                      "operation", &name,
                      NULL);

app/xcf/xcf-load.c

@@ -2515,8 +2515,9 @@ xcf_load_effect_props (XcfInfo      *info,
             xcf_read_int32 (info, (guint32 *) &filter_type, 1);
 
             /* Check if valid property first */
-            if (! (pspec = gegl_operation_find_property (filter->operation_name,
-                                                         filter_prop_name)))
+            if (! (pspec = gegl_operation_find_property_for_version (filter->operation_name,
+                                                                     filter_prop_name,
+                                                                     filter->op_version)))
               {
                 gimp_message (info->gimp, G_OBJECT (info->progress),
                               GIMP_MESSAGE_WARNING,
@@ -3398,8 +3399,8 @@ xcf_load_effect (XcfInfo      *info,
     }
 
   if (filter->op_version &&
-      g_strcmp0 (gegl_operation_get_op_version (filter->operation_name),
-                 filter->op_version) != 0)
+      ! gegl_operation_is_supported_version (filter->operation_name,
+                                             filter->op_version))
     {
       filter->unsupported_operation = TRUE;
 
@@ -3421,6 +3422,9 @@ xcf_load_effect (XcfInfo      *info,
                  "operation", filter->operation_name,
                  NULL);
 
+  if (filter->op_version)
+    gegl_node_set_op_version (filter->operation, filter->op_version);
+
   /* read in the effect properties */
   if (! xcf_load_effect_props (info, &(*filter)))
     goto error;

app/xcf/xcf-save.c

@@ -835,10 +835,11 @@ xcf_save_effect_props (XcfInfo      *info,
                        GimpFilter   *filter,
                        GError      **error)
 {
-  GParamSpec **pspecs;
-  guint        n_pspecs;
-  GeglNode    *node;
-  gchar       *operation;
+  const gchar **names = NULL;
+  GParamSpec  **pspecs;
+  guint         n_pspecs;
+  GeglNode     *node;
+  gchar        *operation;
 
   xcf_check_error (xcf_save_prop (info, image, PROP_VISIBLE, error,
                                   gimp_filter_get_active (filter)), ;);
@@ -864,7 +865,7 @@ xcf_save_effect_props (XcfInfo      *info,
                  "operation", &operation,
                  NULL);
 
-  pspecs = gegl_operation_list_properties (operation, &n_pspecs);
+  pspecs = gegl_node_list_properties (node, &names, &n_pspecs);
 
   for (gint i = 0; i < n_pspecs; i++)
     {
@@ -873,8 +874,7 @@ xcf_save_effect_props (XcfInfo      *info,
       FilterPropType  filter_type = FILTER_PROP_UNKNOWN;
 
       g_value_init (&value, pspec->value_type);
-      gegl_node_get_property (node, pspec->name,
-                              &value);
+      gegl_node_get_property (node, names[i], &value);
 
       switch (G_VALUE_TYPE (&value))
         {
@@ -918,7 +918,7 @@ xcf_save_effect_props (XcfInfo      *info,
                               GIMP_MESSAGE_WARNING,
                               "XCF Warning: argument \"%s\" of filter %s has "
                               "unsupported type %s. It was discarded.",
-                              pspec->name, operation,
+                              names[i], operation,
                               g_type_name (G_VALUE_TYPE (&value)));
               }
             break;
@@ -926,12 +926,13 @@ xcf_save_effect_props (XcfInfo      *info,
 
       if (filter_type != FILTER_PROP_UNKNOWN)
         xcf_check_error (xcf_save_prop (info, image, PROP_FILTER_ARGUMENT, error,
-                         pspec->name, filter_type, value), ;);
+                         names[i], filter_type, value), ;);
 
       g_value_unset (&value);
     }
   g_free (operation);
   g_free (pspecs);
+  g_free (names);
 
   xcf_check_error (xcf_save_prop (info, image, PROP_END, error), ;);