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, 3 insertions, 2 deletions

diff --git a/epan/ftypes/ftype-guid.c b/epan/ftypes/ftype-guid.c
index 290738ae20..20d448d078 100644
--- a/epan/ftypes/ftype-guid.c
+++ b/epan/ftypes/ftype-guid.c
@@ -84,12 +84,13 @@ get_guid(const char *s, e_guid_t *guid)
 }
 
 static gboolean
-guid_from_unparsed(fvalue_t *fv, const char *s, gboolean allow_partial_value _U_, LogFunc logfunc)
+guid_from_unparsed(fvalue_t *fv, const char *s, gboolean allow_partial_value _U_, gchar **err_msg)
 {
      e_guid_t guid;
 
     if (!get_guid(s, &guid)) {
-        logfunc("\"%s\" is not a valid GUID.", s);
+        if (err_msg != NULL)
+            *err_msg = g_strdup_printf("\"%s\" is not a valid GUID.", s);
         return FALSE;
     }