+
+static const char *get_next_line(const char *start, const char *end)
+{
+ const char *nl = memchr(start, '\n', end - start);
+ return nl ? nl + 1 : end;
+}
+
+/*
+ * To allow quick access to the contents of nth line in the
+ * final image, prepare an index in the scoreboard.
+ */
+static int prepare_lines(struct blame_scoreboard *sb)
+{
+ const char *buf = sb->final_buf;
+ unsigned long len = sb->final_buf_size;
+ const char *end = buf + len;
+ const char *p;
+ int *lineno;
+ int num = 0;
+
+ for (p = buf; p < end; p = get_next_line(p, end))
+ num++;
+
+ ALLOC_ARRAY(sb->lineno, num + 1);
+ lineno = sb->lineno;
+
+ for (p = buf; p < end; p = get_next_line(p, end))
+ *lineno++ = p - buf;
+
+ *lineno = len;
+
+ sb->num_lines = num;
+ return sb->num_lines;
+}
+
+static struct commit *find_single_final(struct rev_info *revs,
+ const char **name_p)
+{
+ int i;
+ struct commit *found = NULL;
+ const char *name = NULL;
+
+ for (i = 0; i < revs->pending.nr; i++) {
+ struct object *obj = revs->pending.objects[i].item;
+ if (obj->flags & UNINTERESTING)
+ continue;
+ obj = deref_tag(obj, NULL, 0);
+ if (obj->type != OBJ_COMMIT)
+ die("Non commit %s?", revs->pending.objects[i].name);
+ if (found)
+ die("More than one commit to dig from %s and %s?",
+ revs->pending.objects[i].name, name);
+ found = (struct commit *)obj;
+ name = revs->pending.objects[i].name;
+ }
+ if (name_p)
+ *name_p = name;
+ return found;
+}
+
+static struct commit *dwim_reverse_initial(struct rev_info *revs,
+ const char **name_p)
+{
+ /*
+ * DWIM "git blame --reverse ONE -- PATH" as
+ * "git blame --reverse ONE..HEAD -- PATH" but only do so
+ * when it makes sense.
+ */
+ struct object *obj;
+ struct commit *head_commit;
+ unsigned char head_sha1[20];
+
+ if (revs->pending.nr != 1)
+ return NULL;
+
+ /* Is that sole rev a committish? */
+ obj = revs->pending.objects[0].item;
+ obj = deref_tag(obj, NULL, 0);
+ if (obj->type != OBJ_COMMIT)
+ return NULL;
+
+ /* Do we have HEAD? */
+ if (!resolve_ref_unsafe("HEAD", RESOLVE_REF_READING, head_sha1, NULL))
+ return NULL;
+ head_commit = lookup_commit_reference_gently(head_sha1, 1);
+ if (!head_commit)
+ return NULL;
+
+ /* Turn "ONE" into "ONE..HEAD" then */
+ obj->flags |= UNINTERESTING;
+ add_pending_object(revs, &head_commit->object, "HEAD");
+
+ if (name_p)
+ *name_p = revs->pending.objects[0].name;
+ return (struct commit *)obj;
+}
+
+static struct commit *find_single_initial(struct rev_info *revs,
+ const char **name_p)
+{
+ int i;
+ struct commit *found = NULL;
+ const char *name = NULL;
+
+ /*
+ * There must be one and only one negative commit, and it must be
+ * the boundary.
+ */
+ for (i = 0; i < revs->pending.nr; i++) {
+ struct object *obj = revs->pending.objects[i].item;
+ if (!(obj->flags & UNINTERESTING))
+ continue;
+ obj = deref_tag(obj, NULL, 0);
+ if (obj->type != OBJ_COMMIT)
+ die("Non commit %s?", revs->pending.objects[i].name);
+ if (found)
+ die("More than one commit to dig up from, %s and %s?",
+ revs->pending.objects[i].name, name);
+ found = (struct commit *) obj;
+ name = revs->pending.objects[i].name;
+ }
+
+ if (!name)
+ found = dwim_reverse_initial(revs, &name);
+ if (!name)
+ die("No commit to dig up from?");
+
+ if (name_p)
+ *name_p = name;
+ return found;
+}
+
+void init_scoreboard(struct blame_scoreboard *sb)
+{
+ memset(sb, 0, sizeof(struct blame_scoreboard));
+ sb->move_score = BLAME_DEFAULT_MOVE_SCORE;
+ sb->copy_score = BLAME_DEFAULT_COPY_SCORE;
+}
+
+void setup_scoreboard(struct blame_scoreboard *sb, const char *path, struct blame_origin **orig)
+{
+ const char *final_commit_name = NULL;
+ struct blame_origin *o;
+ struct commit *final_commit = NULL;
+ enum object_type type;
+
+ if (sb->reverse && sb->contents_from)
+ die(_("--contents and --reverse do not blend well."));
+
+ if (!sb->reverse) {
+ sb->final = find_single_final(sb->revs, &final_commit_name);
+ sb->commits.compare = compare_commits_by_commit_date;
+ } else {
+ sb->final = find_single_initial(sb->revs, &final_commit_name);
+ sb->commits.compare = compare_commits_by_reverse_commit_date;
+ }
+
+ if (sb->final && sb->contents_from)
+ die(_("cannot use --contents with final commit object name"));
+
+ if (sb->reverse && sb->revs->first_parent_only)
+ sb->revs->children.name = NULL;
+
+ if (!sb->final) {
+ /*
+ * "--not A B -- path" without anything positive;
+ * do not default to HEAD, but use the working tree
+ * or "--contents".
+ */
+ setup_work_tree();
+ sb->final = fake_working_tree_commit(&sb->revs->diffopt,
+ path, sb->contents_from);
+ add_pending_object(sb->revs, &(sb->final->object), ":");
+ }
+
+ if (sb->reverse && sb->revs->first_parent_only) {
+ final_commit = find_single_final(sb->revs, NULL);
+ if (!final_commit)
+ die(_("--reverse and --first-parent together require specified latest commit"));
+ }
+
+ /*
+ * If we have bottom, this will mark the ancestors of the
+ * bottom commits we would reach while traversing as
+ * uninteresting.
+ */
+ if (prepare_revision_walk(sb->revs))
+ die(_("revision walk setup failed"));
+
+ if (sb->reverse && sb->revs->first_parent_only) {
+ struct commit *c = final_commit;
+
+ sb->revs->children.name = "children";
+ while (c->parents &&
+ oidcmp(&c->object.oid, &sb->final->object.oid)) {
+ struct commit_list *l = xcalloc(1, sizeof(*l));
+
+ l->item = c;
+ if (add_decoration(&sb->revs->children,
+ &c->parents->item->object, l))
+ die("BUG: not unique item in first-parent chain");
+ c = c->parents->item;
+ }
+
+ if (oidcmp(&c->object.oid, &sb->final->object.oid))
+ die(_("--reverse --first-parent together require range along first-parent chain"));
+ }
+
+ if (is_null_oid(&sb->final->object.oid)) {
+ o = sb->final->util;
+ sb->final_buf = xmemdupz(o->file.ptr, o->file.size);
+ sb->final_buf_size = o->file.size;
+ }
+ else {
+ o = get_origin(sb->final, path);
+ if (fill_blob_sha1_and_mode(o))
+ die(_("no such path %s in %s"), path, final_commit_name);
+
+ if (DIFF_OPT_TST(&sb->revs->diffopt, ALLOW_TEXTCONV) &&
+ textconv_object(path, o->mode, &o->blob_oid, 1, (char **) &sb->final_buf,
+ &sb->final_buf_size))
+ ;
+ else
+ sb->final_buf = read_sha1_file(o->blob_oid.hash, &type,
+ &sb->final_buf_size);
+
+ if (!sb->final_buf)
+ die(_("cannot read blob %s for path %s"),
+ oid_to_hex(&o->blob_oid),
+ path);
+ }
+ sb->num_read_blob++;
+ prepare_lines(sb);
+
+ if (orig)
+ *orig = o;
+}