Clean up ftype-conversion and dfilter error message string handling.

Have dfilter_compile() take an additional gchar ** argument, pointing to
a gchar * item that, on error, gets set to point to a g_malloc()ed error
string.  That removes one bit of global state from the display filter
parser, and doesn't impose a fixed limit on the error message strings.

Have fvalue_from_string() and fvalue_from_unparsed() take a gchar **
argument, pointer to a gchar * item, rather than an error-reporting
function, and set the gchar * item to point to a g_malloc()ed error
string on an error.

Allow either gchar ** argument to be null; if the argument is null, no
error message is allocated or provided.

Change-Id: Ibd36b8aaa9bf4234aa6efa1e7fb95f7037493b4c
Reviewed-on: https://code.wireshark.org/review/6608
Reviewed-by: Guy Harris <guy@alum.mit.edu>

1 files changed, 4 insertions, 2 deletions

diff --git a/ui/gtk/color_edit_dlg.c b/ui/gtk/color_edit_dlg.c
index d9c2354f60..33aa800c9c 100644
--- a/ui/gtk/color_edit_dlg.c
+++ b/ui/gtk/color_edit_dlg.c
@@ -369,6 +369,7 @@ color_edit_dlg_ok_cb(GtkWidget *w _U_, gpointer user_data)
   gboolean        filter_disabled;
   color_filter_t *colorf;
   dfilter_t      *compiled_filter;
+  gchar          *err_msg;
   GtkTreeModel   *model;
   GtkTreeIter     iter;
   gchar           fg_str[14], bg_str[14];
@@ -386,11 +387,12 @@ color_edit_dlg_ok_cb(GtkWidget *w _U_, gpointer user_data)
     return;
   }
 
-  if (!dfilter_compile(filter_text, &compiled_filter)) {
+  if (!dfilter_compile(filter_text, &compiled_filter, &err_msg)) {
     simple_dialog(ESD_TYPE_ERROR, ESD_BTN_OK,
                   "Filter \"%s\" didn't compile correctly.\n"
                   " Please try again. Filter unchanged.\n%s\n", filter_name,
-                  dfilter_error_msg);
+                  err_msg);
+    g_free(err_msg);
     g_free(filter_name);
     g_free(filter_text);
     return;