+static void run_external_diff(const char *pgm,
+ const char *name,
+ const char *other,
+ struct diff_filespec *one,
+ struct diff_filespec *two,
+ const char *xfrm_msg,
+ int complete_rewrite)
+{
+ struct diff_tempfile *temp = diff_temp;
+ pid_t pid;
+ int status;
+ static int atexit_asked = 0;
+ const char *othername;
+
+ othername = (other? other : name);
+ if (one && two) {
+ prepare_temp_file(name, &temp[0], one);
+ prepare_temp_file(othername, &temp[1], two);
+ if (! atexit_asked &&
+ (temp[0].name == temp[0].tmp_path ||
+ temp[1].name == temp[1].tmp_path)) {
+ atexit_asked = 1;
+ atexit(remove_tempfile);
+ }
+ signal(SIGINT, remove_tempfile_on_signal);
+ }
+
+ fflush(NULL);
+ pid = fork();
+ if (pid < 0)
+ die("unable to fork");
+ if (!pid) {
+ if (pgm) {
+ if (one && two) {
+ const char *exec_arg[10];
+ const char **arg = &exec_arg[0];
+ *arg++ = pgm;
+ *arg++ = name;
+ *arg++ = temp[0].name;
+ *arg++ = temp[0].hex;
+ *arg++ = temp[0].mode;
+ *arg++ = temp[1].name;
+ *arg++ = temp[1].hex;
+ *arg++ = temp[1].mode;
+ if (other) {
+ *arg++ = other;
+ *arg++ = xfrm_msg;
+ }
+ *arg = NULL;
+ execvp(pgm, (char *const*) exec_arg);
+ }
+ else
+ execlp(pgm, pgm, name, NULL);
+ }
+ /*
+ * otherwise we use the built-in one.
+ */
+ if (one && two)
+ builtin_diff(name, othername, temp, xfrm_msg,
+ complete_rewrite);
+ else
+ printf("* Unmerged path %s\n", name);
+ exit(0);
+ }
+ if (waitpid(pid, &status, 0) < 0 ||
+ !WIFEXITED(status) || WEXITSTATUS(status)) {
+ /* Earlier we did not check the exit status because
+ * diff exits non-zero if files are different, and
+ * we are not interested in knowing that. It was a
+ * mistake which made it harder to quit a diff-*
+ * session that uses the git-apply-patch-script as
+ * the GIT_EXTERNAL_DIFF. A custom GIT_EXTERNAL_DIFF
+ * should also exit non-zero only when it wants to
+ * abort the entire diff-* session.
+ */
+ remove_tempfile();
+ fprintf(stderr, "external diff died, stopping at %s.\n", name);
+ exit(1);
+ }
+ remove_tempfile();
+}
+
+static void diff_fill_sha1_info(struct diff_filespec *one)
+{
+ if (DIFF_FILE_VALID(one)) {
+ if (!one->sha1_valid) {
+ struct stat st;
+ if (stat(one->path, &st) < 0)
+ die("stat %s", one->path);
+ if (index_path(one->sha1, one->path, &st, 0))
+ die("cannot hash %s\n", one->path);
+ }
+ }
+ else
+ memset(one->sha1, 0, 20);
+}
+
+static void run_diff(struct diff_filepair *p)
+{
+ const char *pgm = external_diff();
+ char msg[PATH_MAX*2+300], *xfrm_msg;
+ struct diff_filespec *one;
+ struct diff_filespec *two;
+ const char *name;
+ const char *other;
+ int complete_rewrite = 0;
+ int len;
+
+ if (DIFF_PAIR_UNMERGED(p)) {
+ /* unmerged */
+ run_external_diff(pgm, p->one->path, NULL, NULL, NULL, NULL,
+ 0);
+ return;
+ }
+
+ name = p->one->path;
+ other = (strcmp(name, p->two->path) ? p->two->path : NULL);
+ one = p->one; two = p->two;
+
+ diff_fill_sha1_info(one);
+ diff_fill_sha1_info(two);
+
+ len = 0;
+ switch (p->status) {
+ case DIFF_STATUS_COPIED:
+ len += snprintf(msg + len, sizeof(msg) - len,
+ "similarity index %d%%\n"
+ "copy from %s\n"
+ "copy to %s\n",
+ (int)(0.5 + p->score * 100.0/MAX_SCORE),
+ name, other);
+ break;
+ case DIFF_STATUS_RENAMED:
+ len += snprintf(msg + len, sizeof(msg) - len,
+ "similarity index %d%%\n"
+ "rename from %s\n"
+ "rename to %s\n",
+ (int)(0.5 + p->score * 100.0/MAX_SCORE),
+ name, other);
+ break;
+ case DIFF_STATUS_MODIFIED:
+ if (p->score) {
+ len += snprintf(msg + len, sizeof(msg) - len,
+ "dissimilarity index %d%%\n",
+ (int)(0.5 + p->score *
+ 100.0/MAX_SCORE));
+ complete_rewrite = 1;
+ break;
+ }
+ /* fallthru */
+ default:
+ /* nothing */
+ ;
+ }
+
+ if (memcmp(one->sha1, two->sha1, 20)) {
+ char one_sha1[41];
+ memcpy(one_sha1, sha1_to_hex(one->sha1), 41);
+
+ len += snprintf(msg + len, sizeof(msg) - len,
+ "index %.7s..%.7s", one_sha1,
+ sha1_to_hex(two->sha1));
+ if (one->mode == two->mode)
+ len += snprintf(msg + len, sizeof(msg) - len,
+ " %06o", one->mode);
+ len += snprintf(msg + len, sizeof(msg) - len, "\n");
+ }
+
+ if (len)
+ msg[--len] = 0;
+ xfrm_msg = len ? msg : NULL;
+
+ if (!pgm &&
+ DIFF_FILE_VALID(one) && DIFF_FILE_VALID(two) &&
+ (S_IFMT & one->mode) != (S_IFMT & two->mode)) {
+ /* a filepair that changes between file and symlink
+ * needs to be split into deletion and creation.
+ */
+ struct diff_filespec *null = alloc_filespec(two->path);
+ run_external_diff(NULL, name, other, one, null, xfrm_msg, 0);
+ free(null);
+ null = alloc_filespec(one->path);
+ run_external_diff(NULL, name, other, null, two, xfrm_msg, 0);
+ free(null);
+ }
+ else
+ run_external_diff(pgm, name, other, one, two, xfrm_msg,
+ complete_rewrite);
+}
+
+void diff_setup(struct diff_options *options)
+{
+ memset(options, 0, sizeof(*options));
+ options->output_format = DIFF_FORMAT_RAW;
+ options->line_termination = '\n';
+ options->break_opt = -1;
+ options->rename_limit = -1;
+}
+
+int diff_setup_done(struct diff_options *options)
+{
+ if ((options->find_copies_harder || 0 <= options->rename_limit) &&
+ options->detect_rename != DIFF_DETECT_COPY)
+ return -1;
+ if (options->setup & DIFF_SETUP_USE_CACHE) {
+ if (!active_cache)
+ /* read-cache does not die even when it fails
+ * so it is safe for us to do this here. Also
+ * it does not smudge active_cache or active_nr
+ * when it fails, so we do not have to worry about
+ * cleaning it up oufselves either.
+ */
+ read_cache();
+ }
+ if (options->setup & DIFF_SETUP_USE_SIZE_CACHE)
+ use_size_cache = 1;
+
+ return 0;
+}
+
+int diff_opt_parse(struct diff_options *options, const char **av, int ac)
+{
+ const char *arg = av[0];
+ if (!strcmp(arg, "-p") || !strcmp(arg, "-u"))
+ options->output_format = DIFF_FORMAT_PATCH;
+ else if (!strcmp(arg, "-z"))
+ options->line_termination = 0;
+ else if (!strncmp(arg, "-l", 2))
+ options->rename_limit = strtoul(arg+2, NULL, 10);
+ else if (!strcmp(arg, "--name-only"))
+ options->output_format = DIFF_FORMAT_NAME;
+ else if (!strcmp(arg, "--name-status"))
+ options->output_format = DIFF_FORMAT_NAME_STATUS;
+ else if (!strcmp(arg, "-R"))
+ options->reverse_diff = 1;
+ else if (!strncmp(arg, "-S", 2))
+ options->pickaxe = arg + 2;
+ else if (!strcmp(arg, "-s"))
+ options->output_format = DIFF_FORMAT_NO_OUTPUT;
+ else if (!strncmp(arg, "-O", 2))
+ options->orderfile = arg + 2;
+ else if (!strncmp(arg, "--diff-filter=", 14))
+ options->filter = arg + 14;
+ else if (!strcmp(arg, "--pickaxe-all"))
+ options->pickaxe_opts = DIFF_PICKAXE_ALL;
+ else if (!strncmp(arg, "-B", 2)) {
+ if ((options->break_opt =
+ diff_scoreopt_parse(arg)) == -1)
+ return -1;
+ }
+ else if (!strncmp(arg, "-M", 2)) {
+ if ((options->rename_score =
+ diff_scoreopt_parse(arg)) == -1)
+ return -1;
+ options->detect_rename = DIFF_DETECT_RENAME;
+ }
+ else if (!strncmp(arg, "-C", 2)) {
+ if ((options->rename_score =
+ diff_scoreopt_parse(arg)) == -1)
+ return -1;
+ options->detect_rename = DIFF_DETECT_COPY;
+ }
+ else if (!strcmp(arg, "--find-copies-harder"))
+ options->find_copies_harder = 1;
+ else
+ return 0;
+ return 1;
+}
+
+static int parse_num(const char **cp_p)
+{
+ int num, scale, ch, cnt;
+ const char *cp = *cp_p;
+
+ cnt = num = 0;
+ scale = 1;
+ while ('0' <= (ch = *cp) && ch <= '9') {
+ if (cnt++ < 5) {
+ /* We simply ignore more than 5 digits precision. */
+ scale *= 10;
+ num = num * 10 + ch - '0';
+ }
+ cp++;
+ }
+ *cp_p = cp;
+
+ /* user says num divided by scale and we say internally that
+ * is MAX_SCORE * num / scale.
+ */
+ return (MAX_SCORE * num / scale);
+}
+
+int diff_scoreopt_parse(const char *opt)
+{
+ int opt1, opt2, cmd;
+
+ if (*opt++ != '-')
+ return -1;
+ cmd = *opt++;
+ if (cmd != 'M' && cmd != 'C' && cmd != 'B')
+ return -1; /* that is not a -M, -C nor -B option */
+
+ opt1 = parse_num(&opt);
+ if (cmd != 'B')
+ opt2 = 0;
+ else {
+ if (*opt == 0)
+ opt2 = 0;
+ else if (*opt != '/')
+ return -1; /* we expect -B80/99 or -B80 */