dfilter: Return an error object instead of string

Return an struct containing error information. This simplifies
the interface to more easily provide richer diagnostics in the future.

Add an error code besides a human-readable error string to allow
checking programmatically for errors in a robust manner. Currently
there is only a generic error code, it is expected to increase
in the future.

Move error location information to the struct. Change callers and
implementation to use the new interface.

3 files changed, 12 insertions, 10 deletions

diff --git a/ui/logray/logray_main.cpp b/ui/logray/logray_main.cpp
index db2a044614..774840593c 100644
--- a/ui/logray/logray_main.cpp
+++ b/ui/logray/logray_main.cpp
@@ -428,6 +428,7 @@ int main(int argc, char *qt_argv[])
 #endif
 #endif
     gchar               *err_msg = NULL;
+    df_error_t          *df_err = NULL;
 
     QString              dfilter, read_filter;
 #ifdef HAVE_LIBPCAP
@@ -960,13 +961,13 @@ int main(int argc, char *qt_argv[])
             } else if (global_commandline_info.jfilter != NULL) {
                 dfilter_t *jump_to_filter = NULL;
                 /* try to compile given filter */
-                if (!dfilter_compile(global_commandline_info.jfilter, &jump_to_filter, &err_msg)) {
+                if (!dfilter_compile(global_commandline_info.jfilter, &jump_to_filter, &df_err)) {
                     // Similar code in MainWindow::mergeCaptureFile().
                     QMessageBox::warning(main_w, QObject::tr("Invalid Display Filter"),
                                          QObject::tr("The filter expression %1 isn't a valid display filter. (%2).")
-                                                 .arg(global_commandline_info.jfilter, err_msg),
+                                                 .arg(global_commandline_info.jfilter, df_err->msg),
                                          QMessageBox::Ok);
-                    g_free(err_msg);
+                    dfilter_error_free(df_err);
                 } else {
                     /* Filter ok, jump to the first packet matching the filter
                        conditions. Default search direction is forward, but if
diff --git a/ui/logray/logray_main_window.cpp b/ui/logray/logray_main_window.cpp
index 6c1dd3973a..8151f07b27 100644
--- a/ui/logray/logray_main_window.cpp
+++ b/ui/logray/logray_main_window.cpp
@@ -1164,16 +1164,16 @@ void LograyMainWindow::mergeCaptureFile()
         char        *tmpname;
 
         if (merge_dlg.merge(file_name, read_filter)) {
-            gchar *err_msg;
+            df_error_t *df_err = NULL;
 
-            if (!dfilter_compile(qUtf8Printable(read_filter), &rfcode, &err_msg)) {
+            if (!dfilter_compile(qUtf8Printable(read_filter), &rfcode, &df_err)) {
                 /* Not valid. Tell the user, and go back and run the file
                    selection box again once they dismiss the alert. */
                 // Similar to commandline_info.jfilter section in main().
                 QMessageBox::warning(this, tr("Invalid Read Filter"),
-                                     QString(tr("The filter expression %1 isn't a valid read filter. (%2).").arg(read_filter, err_msg)),
+                                     QString(tr("The filter expression %1 isn't a valid read filter. (%2).").arg(read_filter, df_err->msg)),
                                      QMessageBox::Ok);
-                g_free(err_msg);
+                dfilter_error_free(df_err);
                 continue;
             }
         } else {
diff --git a/ui/logray/logray_main_window_slots.cpp b/ui/logray/logray_main_window_slots.cpp
index d8465aca6d..70fd5b003c 100644
--- a/ui/logray/logray_main_window_slots.cpp
+++ b/ui/logray/logray_main_window_slots.cpp
@@ -161,7 +161,7 @@ bool LograyMainWindow::openCaptureFile(QString cf_path, QString read_filter, uns
 {
     QString file_name = "";
     dfilter_t *rfcode = NULL;
-    gchar *err_msg;
+    df_error_t *df_err = NULL;
     int err;
     gboolean name_param;
     gboolean ret = true;
@@ -194,7 +194,7 @@ bool LograyMainWindow::openCaptureFile(QString cf_path, QString read_filter, uns
             goto finish;
         }
 
-        if (dfilter_compile(qUtf8Printable(read_filter), &rfcode, &err_msg)) {
+        if (dfilter_compile(qUtf8Printable(read_filter), &rfcode, &df_err)) {
             cf_set_rfcode(CaptureFile::globalCapFile(), rfcode);
         } else {
             /* Not valid.  Tell the user, and go back and run the file
@@ -204,8 +204,9 @@ bool LograyMainWindow::openCaptureFile(QString cf_path, QString read_filter, uns
                     QString("The filter expression ") +
                     read_filter +
                     QString(" isn't a valid display filter. (") +
-                    err_msg + QString(")."),
+                    df_err->msg + QString(")."),
                     QMessageBox::Ok);
+            dfilter_error_free(df_err);
 
             if (!name_param) {
                 // go back to the selection dialogue only if the file