From Kovarththanan Rajaratnam via bug 3702:

This patch optimizes the data source name processing in add_new_data_source()
by delaying it. We now simply store the constant string and lazily compute the
name when needed. This gives a performance boost because we only need the name
if we have multiple data sources.

svn path=/trunk/; revision=29066

epan/dissectors/packet-dcerpc-eventlog.c

@@ -1586,7 +1586,7 @@ eventlog_dissect_element_ReadEventLogW_handle_(tvbuff_t *tvb _U_, int offset _U_
 static int
 eventlog_dissect_element_ReadEventLogW_flags(tvbuff_t *tvb _U_, int offset _U_, packet_info *pinfo _U_, proto_tree *tree _U_, guint8 *drep _U_)
 {
-	offset = PIDL_dissect_uint32(tvb, offset, pinfo, tree, drep, hf_eventlog_eventlog_ReadEventLogW_flags, 0);
+	offset = eventlog_dissect_bitmap_eventlogReadFlags(tvb, offset, pinfo, tree, drep, hf_eventlog_eventlog_ReadEventLogW_flags, 0);
 
 	return offset;
 }

epan/frame_data.h

@@ -67,7 +67,8 @@ typedef struct _frame_data {
  */
 typedef struct {
   tvbuff_t *tvb;
-  char *name;
+  gboolean name_initialized;
+  const char *name;
 } data_source;
 
 /* Utility routines used by packet*.c */

epan/libwireshark.def

@@ -485,6 +485,7 @@ get_column_title
 get_column_width_string
 get_datafile_dir
 get_datafile_path
+get_data_source_name
 get_dirname
 get_dissector_table_selector_type
 get_dissector_table_ui_name

epan/packet.c

@@ -197,15 +197,22 @@ add_new_data_source(packet_info *pinfo, tvbuff_t *tvb, const char *name)
 
 	src = ep_alloc(sizeof (data_source));
 	src->tvb = tvb;
-	/*
-	 * XXX - if we require this argument to be a string constant,
-	 * we don't need to allocate a buffer for a copy and make a
-	 * copy, and wouldn't need to free the buffer, either.
-	 */
-	src->name = ep_strdup_printf("%s (%u bytes)", name, tvb_length(tvb));
+    src->name_initialized = FALSE;
+	src->name = name;
 	pinfo->data_src = g_slist_append(pinfo->data_src, src);
 }
 
+const char*
+get_data_source_name(data_source *src)
+{
+	if (!src->name_initialized) {
+		src->name = ep_strdup_printf("%s (%u bytes)", src->name, tvb_length(src->tvb));
+		src->name_initialized = TRUE;
+	}
+
+	return src->name;
+}
+
 /*
  * Free up a frame's list of data sources.
  */

epan/packet.h

@@ -383,6 +383,11 @@ final_registration_all_protocols(void);
 extern void add_new_data_source(packet_info *pinfo, tvbuff_t *tvb,
     const char *name);
 
+/*
+ * Return the data source name.
+ */
+extern const char* get_data_source_name(data_source *src);
+
 /*
  * Free up a frame's list of data sources.
  */

gtk/main_proto_draw.c

@@ -654,7 +654,7 @@ add_byte_views(epan_dissect_t *edt, GtkWidget *tree_view,
 	 */
 	for (src_le = edt->pi.data_src; src_le != NULL; src_le = src_le->next) {
 		src = src_le->data;
-		add_byte_tab(byte_nb_ptr, src->name, src->tvb, edt->tree,
+		add_byte_tab(byte_nb_ptr, get_data_source_name(src), src->tvb, edt->tree,
                              tree_view);
 	}
 

print.c

@@ -771,7 +771,7 @@ print_hex_data(print_stream_t *stream, epan_dissect_t *edt)
 	GSList *src_le;
 	data_source *src;
 	tvbuff_t *tvb;
-	char *name;
+	const char *name;
 	char *line;
 	const guchar *cp;
 	guint length;
@@ -789,7 +789,7 @@ print_hex_data(print_stream_t *stream, epan_dissect_t *edt)
 		src = src_le->data;
 		tvb = src->tvb;
 		if (multiple_sources) {
-			name = src->name;
+			name = get_data_source_name(src);
 			print_line(stream, 0, "");
 			line = g_strdup_printf("%s:", name);
 			print_line(stream, 0, line);