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/rlc_lte_graph.c b/ui/gtk/rlc_lte_graph.c
index 05ad9e03a0..3b0323dcab 100644
--- a/ui/gtk/rlc_lte_graph.c
+++ b/ui/gtk/rlc_lte_graph.c
@@ -892,6 +892,7 @@ static rlc_lte_tap_info *select_rlc_lte_session(capture_file *cf, struct segment
     frame_data     *fdata;
     epan_dissect_t  edt;
     dfilter_t      *sfcode;
+    gchar          *err_msg;
     GString        *error_string;
     nstime_t        rel_ts;
     th_t            th = {0, {NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL}};
@@ -903,8 +904,9 @@ static rlc_lte_tap_info *select_rlc_lte_session(capture_file *cf, struct segment
     fdata = cf->current_frame;
 
     /* no real filter yet */
-    if (!dfilter_compile("rlc-lte", &sfcode)) {
-        simple_dialog(ESD_TYPE_ERROR, ESD_BTN_OK, "%s", dfilter_error_msg);
+    if (!dfilter_compile("rlc-lte", &sfcode, &err_msg)) {
+        simple_dialog(ESD_TYPE_ERROR, ESD_BTN_OK, "%s", err_msg);
+        g_free(err_msg);
         return NULL;
     }