+static int diff_tree_stdin(char *line)
+{
+ int len = strlen(line);
+ unsigned char commit[20], parent[20];
+ unsigned long size, offset;
+ char *buf;
+
+ if (!len || line[len-1] != '\n')
+ return -1;
+ line[len-1] = 0;
+ if (get_sha1_hex(line, commit))
+ return -1;
+ if (isspace(line[40]) && !get_sha1_hex(line+41, parent)) {
+ line[40] = ' ';
+ line[81] = 0;
+ printf("%s:\n", line);
+ return diff_tree_sha1(parent, commit, "");
+ }
+ buf = read_object_with_reference(commit, "commit", &size, NULL);
+ if (!buf)
+ return -1;
+
+ /* More than one parent? */
+ if (ignore_merges) {
+ if (!memcmp(buf + 46 + 48, "parent ", 7))
+ return 0;
+ }
+
+ line[40] = 0;
+ offset = 46;
+ while (offset + 48 < size && !memcmp(buf + offset, "parent ", 7)) {
+ if (get_sha1_hex(buf + offset + 7, parent))
+ return -1;
+ printf("%s %s:\n", line, sha1_to_hex(parent));
+ diff_tree_sha1(parent, commit, "");
+ offset += 48;
+ }
+ return -1;
+}
+