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, 6 insertions, 3 deletions

diff --git a/ui/gtk/find_dlg.c b/ui/gtk/find_dlg.c
index faa9f48b83..7a128e552d 100644
--- a/ui/gtk/find_dlg.c
+++ b/ui/gtk/find_dlg.c
@@ -626,9 +626,12 @@ find_frame_ok_cb(GtkWidget *ok_bt _U_, gpointer parent_w)
     /*
      * Display filter search - try to compile the filter.
      */
-    if (!dfilter_compile(filter_text, &sfcode)) {
+    gchar *err_msg;
+
+    if (!dfilter_compile(filter_text, &sfcode, &err_msg)) {
       /* The attempt failed; report an error. */
-      bad_dfilter_alert_box(GTK_WIDGET(parent_w), filter_text);
+      bad_dfilter_alert_box(GTK_WIDGET(parent_w), filter_text, err_msg);
+      g_free(err_msg);
       return;
     }
 
@@ -752,7 +755,7 @@ find_previous_next(GtkWidget *w, gpointer d, search_direction dir)
       }
       g_free(string);
     } else {
-      if (!dfilter_compile(cfile.sfilter, &sfcode)) {
+      if (!dfilter_compile(cfile.sfilter, &sfcode, NULL)) {
 	/*
 	 * XXX - this shouldn't happen, as we've already successfully
 	 * translated the string once.