Merge branch 'jc/blame' into next

* jc/blame:
  blame -S <ancestry-file>
  Match ofs/cnt types in diff interface.

diff --combined blame.c
index a596410,75cffd8..6730b10
--- 1/blame.c
--- 2/blame.c
+++ b/blame.c
@@@ -703,11 -703,30 +703,30 @@@ static void* topo_getter(struct commit
        return util->topo_data;
  }
  
+ static int read_ancestry(const char *graft_file,
+                        unsigned char **start_sha1)
+ {
+       FILE *fp = fopen(graft_file, "r");
+       char buf[1024];
+       if (!fp)
+               return -1;
+       while (fgets(buf, sizeof(buf), fp)) {
+               /* The format is just "Commit Parent1 Parent2 ...\n" */
+               int len = strlen(buf);
+               struct commit_graft *graft = read_graft_line(buf, len);
+               register_commit_graft(graft, 0);
+               if (!*start_sha1)
+                       *start_sha1 = graft->sha1;
+       }
+       fclose(fp);
+       return 0;
+ }
+ 
  int main(int argc, const char **argv)
  {
        int i;
        struct commit *initial = NULL;
-       unsigned char sha1[20];
+       unsigned char sha1[20], *sha1_p = NULL;
  
        const char *filename = NULL, *commit = NULL;
        char filename_buf[256];
@@@ -741,6 -760,14 +760,14 @@@
                                  !strcmp(argv[i], "--compability")) {
                                compability = 1;
                                continue;
+                       } else if(!strcmp(argv[i], "-S")) {
+                               if (i + 1 < argc &&
+                                   !read_ancestry(argv[i + 1], &sha1_p)) {
+                                       compability = 1;
+                                       i++;
+                                       continue;
+                               }
+                               usage(blame_usage);
                        } else if(!strcmp(argv[i], "--")) {
                                options = 0;
                                continue;
@@@ -762,7 -789,9 +789,9 @@@
  
        if(!filename)
                usage(blame_usage);
-       if(!commit)
+       if (commit && sha1_p)
+               usage(blame_usage);
+       else if(!commit)
                commit = "HEAD";
  
        if(prefix)
@@@ -771,9 -800,12 +800,12 @@@
                strcpy(filename_buf, filename);
        filename = filename_buf;
  
-       if (get_sha1(commit, sha1))
-               die("get_sha1 failed, commit '%s' not found", commit);
-       start_commit = lookup_commit_reference(sha1);
+       if (!sha1_p) {
+               if (get_sha1(commit, sha1))
+                       die("get_sha1 failed, commit '%s' not found", commit);
+               sha1_p = sha1;
+       }
+       start_commit = lookup_commit_reference(sha1_p);
        get_util(start_commit)->pathname = filename;
        if (fill_util_info(start_commit)) {
                printf("%s not found in %s\n", filename, commit);
@@@ -787,7 -819,6 +819,7 @@@
        rev.prune_fn = simplify_commit;
        rev.topo_setter = topo_setter;
        rev.topo_getter = topo_getter;
 +      rev.parents = 1;
        rev.limited = 1;
  
        commit_list_insert(start_commit, &rev.commits);