+ int retval;
+
+ tree1 = read_object_with_reference(old, "tree", &size1, 0);
+ if (!tree1)
+ die("unable to read source tree (%s)", sha1_to_hex(old));
+ tree2 = read_object_with_reference(new, "tree", &size2, 0);
+ if (!tree2)
+ die("unable to read destination tree (%s)", sha1_to_hex(new));
+ retval = diff_tree(tree1, size1, tree2, size2, base);
+ free(tree1);
+ free(tree2);
+ return retval;
+}
+
+static int diff_tree_sha1_top(const unsigned char *old,
+ const unsigned char *new, const char *base)
+{
+ int ret;
+
+ diff_setup(detect_rename, diff_score_opt, reverse_diff,
+ (generate_patch ? -1 : line_termination),
+ 0, 0);
+ ret = diff_tree_sha1(old, new, base);
+ diff_flush();
+ return ret;
+}
+
+static int diff_root_tree(const unsigned char *new, const char *base)
+{
+ int retval;
+ void *tree;
+ unsigned long size;
+
+ diff_setup(detect_rename, diff_score_opt, reverse_diff,
+ (generate_patch ? -1 : line_termination),
+ 0, 0);
+ tree = read_object_with_reference(new, "tree", &size, 0);
+ if (!tree)
+ die("unable to read root tree (%s)", sha1_to_hex(new));
+ retval = diff_tree("", 0, tree, size, base);
+ free(tree);
+ diff_flush();
+ return retval;
+}
+
+static int get_one_line(const char *msg, unsigned long len)
+{
+ int ret = 0;
+
+ while (len--) {
+ ret++;
+ if (*msg++ == '\n')
+ break;
+ }
+ return ret;
+}
+
+static int add_author_info(char *buf, const char *line, int len)
+{
+ char *date;
+ unsigned int namelen;
+ unsigned long time;
+ int tz;
+
+ line += strlen("author ");
+ date = strchr(line, '>');
+ if (!date)
+ return 0;
+ namelen = ++date - line;
+ time = strtoul(date, &date, 10);
+ tz = strtol(date, NULL, 10);
+
+ return sprintf(buf, "Author: %.*s\nDate: %s\n",
+ namelen, line,
+ show_date(time, tz));
+}
+
+static char *generate_header(const char *commit, const char *parent, const char *msg, unsigned long len)
+{
+ static char this_header[1000];
+ int offset;
+
+ offset = sprintf(this_header, "%s%s (from %s)\n", header_prefix, commit, parent);
+ if (verbose_header) {
+ int hdr = 1;
+
+ for (;;) {
+ const char *line = msg;
+ int linelen = get_one_line(msg, len);
+
+ if (!linelen)
+ break;
+ if (offset + linelen + 10 > sizeof(this_header))
+ break;
+
+ msg += linelen;
+ len -= linelen;
+ if (linelen == 1)
+ hdr = 0;
+ if (hdr) {
+ if (!memcmp(line, "author ", 7))
+ offset += add_author_info(this_header + offset, line, linelen);
+ continue;
+ }
+ memset(this_header + offset, ' ', 4);
+ memcpy(this_header + offset + 4, line, linelen);
+ offset += linelen + 4;
+ }
+ this_header[offset++] = '\n';
+ this_header[offset] = 0;
+ }
+
+ return this_header;
+}
+
+static int diff_tree_commit(const unsigned char *commit, const char *name)
+{
+ unsigned long size, offset;
+ char *buf = read_object_with_reference(commit, "commit", &size, NULL);
+
+ if (!buf)
+ return -1;
+
+ if (!name) {
+ static char commit_name[60];
+ strcpy(commit_name, sha1_to_hex(commit));
+ name = commit_name;
+ }
+
+ /* Root commit? */
+ if (show_root_diff && memcmp(buf + 46, "parent ", 7)) {
+ header = generate_header(name, "root", buf, size);
+ diff_root_tree(commit, "");
+ }
+
+ /* More than one parent? */
+ if (ignore_merges) {
+ if (!memcmp(buf + 46 + 48, "parent ", 7))
+ return 0;
+ }
+
+ offset = 46;
+ while (offset + 48 < size && !memcmp(buf + offset, "parent ", 7)) {
+ unsigned char parent[20];
+ if (get_sha1_hex(buf + offset + 7, parent))
+ return -1;
+ header = generate_header(name, sha1_to_hex(parent), buf, size);
+ diff_tree_sha1_top(parent, commit, "");
+ if (!header && verbose_header)
+ header_prefix = "\ndiff-tree ";
+ offset += 48;
+ }
+ return 0;
+}
+
+static int diff_tree_stdin(char *line)
+{
+ int len = strlen(line);
+ unsigned char commit[20], parent[20];
+ static char this_header[1000];
+
+ 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] = 0;
+ line[81] = 0;
+ sprintf(this_header, "%s (from %s)\n", line, line+41);
+ header = this_header;
+ return diff_tree_sha1_top(parent, commit, "");
+ }
+ line[40] = 0;
+ return diff_tree_commit(commit, line);
+}
+
+static char *diff_tree_usage =
+"git-diff-tree [-p] [-r] [-z] [--stdin] [-M] [-R] [-m] [-s] [-v] <tree-ish> <tree-ish>";
+
+int main(int argc, char **argv)
+{
+ int nr_sha1;
+ char line[1000];
+ unsigned char sha1[2][20];
+
+ nr_sha1 = 0;
+ for (;;) {
+ char *arg;
+
+ argv++;
+ argc--;
+ arg = *argv;
+ if (!arg)
+ break;
+
+ if (*arg != '-') {
+ if (nr_sha1 < 2 && !get_sha1(arg, sha1[nr_sha1])) {
+ nr_sha1++;
+ continue;
+ }
+ break;
+ }
+
+ if (!strcmp(arg, "--")) {
+ argv++;
+ argc--;
+ break;
+ }
+ if (!strcmp(arg, "-r")) {
+ recursive = 1;
+ continue;
+ }
+ if (!strcmp(arg, "-R")) {
+ reverse_diff = 1;
+ continue;
+ }
+ if (!strcmp(arg, "-p")) {
+ recursive = generate_patch = 1;
+ continue;
+ }
+ if (!strncmp(arg, "-M", 2)) {
+ detect_rename = recursive = generate_patch = 1;
+ diff_score_opt = diff_scoreopt_parse(arg);
+ continue;
+ }
+ if (!strcmp(arg, "-z")) {
+ line_termination = '\0';
+ continue;
+ }
+ if (!strcmp(arg, "-m")) {
+ ignore_merges = 0;
+ continue;
+ }
+ if (!strcmp(arg, "-s")) {
+ silent = 1;
+ continue;
+ }
+ if (!strcmp(arg, "-v")) {
+ verbose_header = 1;
+ header_prefix = "diff-tree ";
+ continue;
+ }
+ if (!strcmp(arg, "--stdin")) {
+ read_stdin = 1;
+ continue;
+ }
+ if (!strcmp(arg, "--root")) {
+ show_root_diff = 1;
+ continue;
+ }
+ usage(diff_tree_usage);
+ }
+
+ if (argc > 0) {
+ int i;
+
+ paths = argv;
+ nr_paths = argc;
+ pathlens = xmalloc(nr_paths * sizeof(int));
+ for (i=0; i<nr_paths; i++)
+ pathlens[i] = strlen(paths[i]);
+ }
+
+ switch (nr_sha1) {
+ case 0:
+ if (!read_stdin)
+ usage(diff_tree_usage);
+ break;
+ case 1:
+ diff_tree_commit(sha1[0], NULL);
+ break;
+ case 2:
+ diff_tree_sha1_top(sha1[0], sha1[1], "");
+ break;
+ }
+
+ if (!read_stdin)
+ return 0;
+
+ while (fgets(line, sizeof(line), stdin))
+ diff_tree_stdin(line);
+
+ return 0;