1 files changed, 4 insertions, 1 deletions

diff --git a/ui-diff.c b/ui-diff.c
index 7ec5701..999b6f3 100644
--- a/ui-diff.c
+++ b/ui-diff.c
@@ -1,102 +1,105 @@
 /* ui-diff.c: show diff between two blobs
  *
  * Copyright (C) 2006 Lars Hjemli
  *
  * Licensed under GNU General Public License v2
  *   (see COPYING for full license text)
  */
 
 #include "cgit.h"
 
 
 /*
  * print a single line returned from xdiff
  */
 static void print_line(char *line, int len)
 {
         char *class = "ctx";
         char c = line[len-1];
 
         if (line[0] == '+')
                 class = "add";
         else if (line[0] == '-')
                 class = "del";
         else if (line[0] == '@')
                 class = "hunk";
 
         htmlf("<div class='%s'>", class);
         line[len-1] = '\0';
         html_txt(line);
         html("</div>");
         line[len-1] = c;
 }
 
 static void header(unsigned char *sha1, char *path1,
                    unsigned char *sha2, char *path2)
 {
         char *abbrev1, *abbrev2;
-
+        if (is_null_sha1(sha1))
+                path1 = "dev/null";
+        if (is_null_sha1(sha2))
+                path2 = "dev/null";
         html("<tr><td>");
         html("<div class='head'>");
         html("diff --git a/");
         html_txt(path1);
         html(" b/");
         html_txt(path2);
         abbrev1 = xstrdup(find_unique_abbrev(sha1, DEFAULT_ABBREV));
         abbrev2 = xstrdup(find_unique_abbrev(sha2, DEFAULT_ABBREV));
         htmlf("\nindex %s..%s", abbrev1, abbrev2);
         free(abbrev1);
         free(abbrev2);
         html("\n--- a/");
         html_txt(path1);
         html("\n+++ b/");
         html_txt(path2);
         html("</div>");
 }
 
 static void filepair_cb(struct diff_filepair *pair)
 {
         header(pair->one->sha1, pair->one->path,
                pair->two->sha1, pair->two->path);
         if (cgit_diff_files(pair->one->sha1, pair->two->sha1, print_line))
                 cgit_print_error("Error running diff");
         html("</tr></td>");
 }
 
 void cgit_print_diff(const char *old_hex, const char *new_hex, char *path)
 {
         unsigned char sha1[20], sha2[20];
         enum object_type type;
         unsigned long size;
 
         get_sha1(old_hex, sha1);
         get_sha1(new_hex, sha2);
 
         type = sha1_object_info(sha1, &size);
         if (type == OBJ_BAD) {
                 type = sha1_object_info(sha2, &size);
                 if (type == OBJ_BAD) {
                         cgit_print_error(fmt("Bad object names: %s, %s", old_hex, new_hex));
                         return;
                 }
         }
 
         html("<table class='diff'>");
         switch(type) {
         case OBJ_BLOB:
                 html("<tr><td>");
                 header(sha1, path, sha2, path);
                 if (cgit_diff_files(sha1, sha2, print_line))
                         cgit_print_error("Error running diff");
                 html("</tr></td>");
                 break;
         case OBJ_TREE:
                 cgit_diff_tree(sha1, sha2, filepair_cb);
                 break;
         default:
                 cgit_print_error(fmt("Unhandled object type: %s",
                                      typename(type)));
                 break;
         }
         html("</td></tr></table>");
 }