int show_file_header)
 {
        struct diff_options *opt = &rev->diffopt;
-       int abbrev = DIFF_OPT_TST(opt, FULL_INDEX) ? GIT_SHA1_HEXSZ : DEFAULT_ABBREV;
+       int abbrev = opt->flags.full_index ? GIT_SHA1_HEXSZ : DEFAULT_ABBREV;
        const char *a_prefix = opt->a_prefix ? opt->a_prefix : "a/";
        const char *b_prefix = opt->b_prefix ? opt->b_prefix : "b/";
        const char *c_meta = diff_get_color_opt(opt, DIFF_METAINFO);
        userdiff = userdiff_find_by_path(elem->path);
        if (!userdiff)
                userdiff = userdiff_find_by_name("default");
-       if (DIFF_OPT_TST(opt, ALLOW_TEXTCONV))
+       if (opt->flags.allow_textconv)
                textconv = userdiff_get_textconv(userdiff);
 
        /* Read the result of merge first */
                        elem->mode = canon_mode(st.st_mode);
                } else if (S_ISDIR(st.st_mode)) {
                        struct object_id oid;
-                       if (resolve_gitlink_ref(elem->path, "HEAD", oid.hash) < 0)
+                       if (resolve_gitlink_ref(elem->path, "HEAD", &oid) < 0)
                                result = grab_blob(&elem->oid, elem->mode,
                                                   &result_size, NULL, NULL);
                        else
                        if (is_file) {
                                struct strbuf buf = STRBUF_INIT;
 
-                               if (convert_to_git(elem->path, result, len, &buf, safe_crlf)) {
+                               if (convert_to_git(&the_index, elem->path, result, len, &buf, safe_crlf)) {
                                        free(result);
                                        result = strbuf_detach(&buf, &len);
                                        result_size = len;
        struct diff_options *opt)
 {
        int i, nparent = parents->nr;
-       const unsigned char **parents_sha1;
+       const struct object_id **parents_oid;
        struct combine_diff_path paths_head;
        struct strbuf base;
 
-       ALLOC_ARRAY(parents_sha1, nparent);
+       ALLOC_ARRAY(parents_oid, nparent);
        for (i = 0; i < nparent; i++)
-               parents_sha1[i] = parents->oid[i].hash;
+               parents_oid[i] = &parents->oid[i];
 
        /* fake list head, so worker can assume it is non-NULL */
        paths_head.next = NULL;
 
        strbuf_init(&base, PATH_MAX);
-       diff_tree_paths(&paths_head, oid->hash, parents_sha1, nparent, &base, opt);
+       diff_tree_paths(&paths_head, oid, parents_oid, nparent, &base, opt);
 
        strbuf_release(&base);
-       free(parents_sha1);
+       free(parents_oid);
        return paths_head.next;
 }
 
 
        diffopts = *opt;
        copy_pathspec(&diffopts.pathspec, &opt->pathspec);
-       DIFF_OPT_SET(&diffopts, RECURSIVE);
-       DIFF_OPT_CLR(&diffopts, ALLOW_EXTERNAL);
+       diffopts.flags.recursive = 1;
+       diffopts.flags.allow_external = 0;
 
        /* find set of paths that everybody touches
         *
         * NOTE please keep this semantically in sync with diffcore_std()
         */
        need_generic_pathscan = opt->skip_stat_unmatch  ||
-                       DIFF_OPT_TST(opt, FOLLOW_RENAMES)       ||
+                       opt->flags.follow_renames       ||
                        opt->break_opt != -1    ||
                        opt->detect_rename      ||
                        opt->pickaxe            ||