1/*
2 * "git difftool" builtin command
3 *
4 * This is a wrapper around the GIT_EXTERNAL_DIFF-compatible
5 * git-difftool--helper script.
6 *
7 * This script exports GIT_EXTERNAL_DIFF and GIT_PAGER for use by git.
8 * The GIT_DIFF* variables are exported for use by git-difftool--helper.
9 *
10 * Any arguments that are unknown to this script are forwarded to 'git diff'.
11 *
12 * Copyright (C) 2016 Johannes Schindelin
13 */
14#define USE_THE_INDEX_COMPATIBILITY_MACROS
15#include "cache.h"
16#include "config.h"
17#include "builtin.h"
18#include "run-command.h"
19#include "exec-cmd.h"
20#include "parse-options.h"
21#include "argv-array.h"
22#include "strbuf.h"
23#include "lockfile.h"
24#include "object-store.h"
25#include "dir.h"
26static char *diff_gui_tool;
28static int trust_exit_code;
29static const char *const builtin_difftool_usage[] = {
31 N_("git difftool [<options>] [<commit> [<commit>]] [--] [<path>...]"),
32 NULL
33};
34static int difftool_config(const char *var, const char *value, void *cb)
36{
37 if (!strcmp(var, "diff.guitool")) {
38 diff_gui_tool = xstrdup(value);
39 return 0;
40 }
41 if (!strcmp(var, "difftool.trustexitcode")) {
43 trust_exit_code = git_config_bool(var, value);
44 return 0;
45 }
46 return git_default_config(var, value, cb);
48}
49static int print_tool_help(void)
51{
52 const char *argv[] = { "mergetool", "--tool-help=diff", NULL };
53 return run_command_v_opt(argv, RUN_GIT_CMD);
54}
55static int parse_index_info(char *p, int *mode1, int *mode2,
57 struct object_id *oid1, struct object_id *oid2,
58 char *status)
59{
60 if (*p != ':')
61 return error("expected ':', got '%c'", *p);
62 *mode1 = (int)strtol(p + 1, &p, 8);
63 if (*p != ' ')
64 return error("expected ' ', got '%c'", *p);
65 *mode2 = (int)strtol(p + 1, &p, 8);
66 if (*p != ' ')
67 return error("expected ' ', got '%c'", *p);
68 if (parse_oid_hex(++p, oid1, (const char **)&p))
69 return error("expected object ID, got '%s'", p);
70 if (*p != ' ')
71 return error("expected ' ', got '%c'", *p);
72 if (parse_oid_hex(++p, oid2, (const char **)&p))
73 return error("expected object ID, got '%s'", p);
74 if (*p != ' ')
75 return error("expected ' ', got '%c'", *p);
76 *status = *++p;
77 if (!*status)
78 return error("missing status");
79 if (p[1] && !isdigit(p[1]))
80 return error("unexpected trailer: '%s'", p + 1);
81 return 0;
82}
83/*
85 * Remove any trailing slash from $workdir
86 * before starting to avoid double slashes in symlink targets.
87 */
88static void add_path(struct strbuf *buf, size_t base_len, const char *path)
89{
90 strbuf_setlen(buf, base_len);
91 if (buf->len && buf->buf[buf->len - 1] != '/')
92 strbuf_addch(buf, '/');
93 strbuf_addstr(buf, path);
94}
95/*
97 * Determine whether we can simply reuse the file in the worktree.
98 */
99static int use_wt_file(const char *workdir, const char *name,
100 struct object_id *oid)
101{
102 struct strbuf buf = STRBUF_INIT;
103 struct stat st;
104 int use = 0;
105 strbuf_addstr(&buf, workdir);
107 add_path(&buf, buf.len, name);
108 if (!lstat(buf.buf, &st) && !S_ISLNK(st.st_mode)) {
110 struct object_id wt_oid;
111 int fd = open(buf.buf, O_RDONLY);
112 if (fd >= 0 &&
114 !index_fd(&the_index, &wt_oid, fd, &st, OBJ_BLOB, name, 0)) {
115 if (is_null_oid(oid)) {
116 oidcpy(oid, &wt_oid);
117 use = 1;
118 } else if (oideq(oid, &wt_oid))
119 use = 1;
120 }
121 }
122 strbuf_release(&buf);
124 return use;
126}
127struct working_tree_entry {
129 struct hashmap_entry entry;
130 char path[FLEX_ARRAY];
131};
132static int working_tree_entry_cmp(const void *unused_cmp_data,
134 const void *entry,
135 const void *entry_or_key,
136 const void *unused_keydata)
137{
138 const struct working_tree_entry *a = entry;
139 const struct working_tree_entry *b = entry_or_key;
140 return strcmp(a->path, b->path);
141}
142/*
144 * The `left` and `right` entries hold paths for the symlinks hashmap,
145 * and a SHA-1 surrounded by brief text for submodules.
146 */
147struct pair_entry {
148 struct hashmap_entry entry;
149 char left[PATH_MAX], right[PATH_MAX];
150 const char path[FLEX_ARRAY];
151};
152static int pair_cmp(const void *unused_cmp_data,
154 const void *entry,
155 const void *entry_or_key,
156 const void *unused_keydata)
157{
158 const struct pair_entry *a = entry;
159 const struct pair_entry *b = entry_or_key;
160 return strcmp(a->path, b->path);
162}
163static void add_left_or_right(struct hashmap *map, const char *path,
165 const char *content, int is_right)
166{
167 struct pair_entry *e, *existing;
168 FLEX_ALLOC_STR(e, path, path);
170 hashmap_entry_init(e, strhash(path));
171 existing = hashmap_get(map, e, NULL);
172 if (existing) {
173 free(e);
174 e = existing;
175 } else {
176 e->left[0] = e->right[0] = '\0';
177 hashmap_add(map, e);
178 }
179 strlcpy(is_right ? e->right : e->left, content, PATH_MAX);
180}
181struct path_entry {
183 struct hashmap_entry entry;
184 char path[FLEX_ARRAY];
185};
186static int path_entry_cmp(const void *unused_cmp_data,
188 const void *entry,
189 const void *entry_or_key,
190 const void *key)
191{
192 const struct path_entry *a = entry;
193 const struct path_entry *b = entry_or_key;
194 return strcmp(a->path, key ? key : b->path);
196}
197static void changed_files(struct hashmap *result, const char *index_path,
199 const char *workdir)
200{
201 struct child_process update_index = CHILD_PROCESS_INIT;
202 struct child_process diff_files = CHILD_PROCESS_INIT;
203 struct strbuf index_env = STRBUF_INIT, buf = STRBUF_INIT;
204 const char *git_dir = absolute_path(get_git_dir()), *env[] = {
205 NULL, NULL
206 };
207 FILE *fp;
208 strbuf_addf(&index_env, "GIT_INDEX_FILE=%s", index_path);
210 env[0] = index_env.buf;
211 argv_array_pushl(&update_index.args,
213 "--git-dir", git_dir, "--work-tree", workdir,
214 "update-index", "--really-refresh", "-q",
215 "--unmerged", NULL);
216 update_index.no_stdin = 1;
217 update_index.no_stdout = 1;
218 update_index.no_stderr = 1;
219 update_index.git_cmd = 1;
220 update_index.use_shell = 0;
221 update_index.clean_on_exit = 1;
222 update_index.dir = workdir;
223 update_index.env = env;
224 /* Ignore any errors of update-index */
225 run_command(&update_index);
226 argv_array_pushl(&diff_files.args,
228 "--git-dir", git_dir, "--work-tree", workdir,
229 "diff-files", "--name-only", "-z", NULL);
230 diff_files.no_stdin = 1;
231 diff_files.git_cmd = 1;
232 diff_files.use_shell = 0;
233 diff_files.clean_on_exit = 1;
234 diff_files.out = -1;
235 diff_files.dir = workdir;
236 diff_files.env = env;
237 if (start_command(&diff_files))
238 die("could not obtain raw diff");
239 fp = xfdopen(diff_files.out, "r");
240 while (!strbuf_getline_nul(&buf, fp)) {
241 struct path_entry *entry;
242 FLEX_ALLOC_STR(entry, path, buf.buf);
243 hashmap_entry_init(entry, strhash(buf.buf));
244 hashmap_add(result, entry);
245 }
246 fclose(fp);
247 if (finish_command(&diff_files))
248 die("diff-files did not exit properly");
249 strbuf_release(&index_env);
250 strbuf_release(&buf);
251}
252static NORETURN void exit_cleanup(const char *tmpdir, int exit_code)
254{
255 struct strbuf buf = STRBUF_INIT;
256 strbuf_addstr(&buf, tmpdir);
257 remove_dir_recursively(&buf, 0);
258 if (exit_code)
259 warning(_("failed: %d"), exit_code);
260 exit(exit_code);
261}
262static int ensure_leading_directories(char *path)
264{
265 switch (safe_create_leading_directories(path)) {
266 case SCLD_OK:
267 case SCLD_EXISTS:
268 return 0;
269 default:
270 return error(_("could not create leading directories "
271 "of '%s'"), path);
272 }
273}
274/*
276 * Unconditional writing of a plain regular file is what
277 * "git difftool --dir-diff" wants to do for symlinks. We are preparing two
278 * temporary directories to be fed to a Git-unaware tool that knows how to
279 * show a diff of two directories (e.g. "diff -r A B").
280 *
281 * Because the tool is Git-unaware, if a symbolic link appears in either of
282 * these temporary directories, it will try to dereference and show the
283 * difference of the target of the symbolic link, which is not what we want,
284 * as the goal of the dir-diff mode is to produce an output that is logically
285 * equivalent to what "git diff" produces.
286 *
287 * Most importantly, we want to get textual comparison of the result of the
288 * readlink(2). get_symlink() provides that---it returns the contents of
289 * the symlink that gets written to a regular file to force the external tool
290 * to compare the readlink(2) result as text, even on a filesystem that is
291 * capable of doing a symbolic link.
292 */
293static char *get_symlink(const struct object_id *oid, const char *path)
294{
295 char *data;
296 if (is_null_oid(oid)) {
297 /* The symlink is unknown to Git so read from the filesystem */
298 struct strbuf link = STRBUF_INIT;
299 if (has_symlinks) {
300 if (strbuf_readlink(&link, path, strlen(path)))
301 die(_("could not read symlink %s"), path);
302 } else if (strbuf_read_file(&link, path, 128))
303 die(_("could not read symlink file %s"), path);
304 data = strbuf_detach(&link, NULL);
306 } else {
307 enum object_type type;
308 unsigned long size;
309 data = read_object_file(oid, &type, &size);
310 if (!data)
311 die(_("could not read object %s for symlink %s"),
312 oid_to_hex(oid), path);
313 }
314 return data;
316}
317static int checkout_path(unsigned mode, struct object_id *oid,
319 const char *path, const struct checkout *state)
320{
321 struct cache_entry *ce;
322 int ret;
323 ce = make_transient_cache_entry(mode, oid, path, 0);
325 ret = checkout_entry(ce, state, NULL, NULL);
326 discard_cache_entry(ce);
328 return ret;
329}
330static int run_dir_diff(const char *extcmd, int symlinks, const char *prefix,
332 int argc, const char **argv)
333{
334 char tmpdir[PATH_MAX];
335 struct strbuf info = STRBUF_INIT, lpath = STRBUF_INIT;
336 struct strbuf rpath = STRBUF_INIT, buf = STRBUF_INIT;
337 struct strbuf ldir = STRBUF_INIT, rdir = STRBUF_INIT;
338 struct strbuf wtdir = STRBUF_INIT;
339 char *lbase_dir, *rbase_dir;
340 size_t ldir_len, rdir_len, wtdir_len;
341 const char *workdir, *tmp;
342 int ret = 0, i;
343 FILE *fp;
344 struct hashmap working_tree_dups, submodules, symlinks2;
345 struct hashmap_iter iter;
346 struct pair_entry *entry;
347 struct index_state wtindex;
348 struct checkout lstate, rstate;
349 int rc, flags = RUN_GIT_CMD, err = 0;
350 struct child_process child = CHILD_PROCESS_INIT;
351 const char *helper_argv[] = { "difftool--helper", NULL, NULL, NULL };
352 struct hashmap wt_modified, tmp_modified;
353 int indices_loaded = 0;
354 workdir = get_git_work_tree();
356 /* Setup temp directories */
358 tmp = getenv("TMPDIR");
359 xsnprintf(tmpdir, sizeof(tmpdir), "%s/git-difftool.XXXXXX", tmp ? tmp : "/tmp");
360 if (!mkdtemp(tmpdir))
361 return error("could not create '%s'", tmpdir);
362 strbuf_addf(&ldir, "%s/left/", tmpdir);
363 strbuf_addf(&rdir, "%s/right/", tmpdir);
364 strbuf_addstr(&wtdir, workdir);
365 if (!wtdir.len || !is_dir_sep(wtdir.buf[wtdir.len - 1]))
366 strbuf_addch(&wtdir, '/');
367 mkdir(ldir.buf, 0700);
368 mkdir(rdir.buf, 0700);
369 memset(&wtindex, 0, sizeof(wtindex));
371 memset(&lstate, 0, sizeof(lstate));
373 lstate.base_dir = lbase_dir = xstrdup(ldir.buf);
374 lstate.base_dir_len = ldir.len;
375 lstate.force = 1;
376 memset(&rstate, 0, sizeof(rstate));
377 rstate.base_dir = rbase_dir = xstrdup(rdir.buf);
378 rstate.base_dir_len = rdir.len;
379 rstate.force = 1;
380 ldir_len = ldir.len;
382 rdir_len = rdir.len;
383 wtdir_len = wtdir.len;
384 hashmap_init(&working_tree_dups, working_tree_entry_cmp, NULL, 0);
386 hashmap_init(&submodules, pair_cmp, NULL, 0);
387 hashmap_init(&symlinks2, pair_cmp, NULL, 0);
388 child.no_stdin = 1;
390 child.git_cmd = 1;
391 child.use_shell = 0;
392 child.clean_on_exit = 1;
393 child.dir = prefix;
394 child.out = -1;
395 argv_array_pushl(&child.args, "diff", "--raw", "--no-abbrev", "-z",
396 NULL);
397 for (i = 0; i < argc; i++)
398 argv_array_push(&child.args, argv[i]);
399 if (start_command(&child))
400 die("could not obtain raw diff");
401 fp = xfdopen(child.out, "r");
402 /* Build index info for left and right sides of the diff */
404 i = 0;
405 while (!strbuf_getline_nul(&info, fp)) {
406 int lmode, rmode;
407 struct object_id loid, roid;
408 char status;
409 const char *src_path, *dst_path;
410 if (starts_with(info.buf, "::"))
412 die(N_("combined diff formats('-c' and '--cc') are "
413 "not supported in\n"
414 "directory diff mode('-d' and '--dir-diff')."));
415 if (parse_index_info(info.buf, &lmode, &rmode, &loid, &roid,
417 &status))
418 break;
419 if (strbuf_getline_nul(&lpath, fp))
420 break;
421 src_path = lpath.buf;
422 i++;
424 if (status != 'C' && status != 'R') {
425 dst_path = src_path;
426 } else {
427 if (strbuf_getline_nul(&rpath, fp))
428 break;
429 dst_path = rpath.buf;
430 }
431 if (S_ISGITLINK(lmode) || S_ISGITLINK(rmode)) {
433 strbuf_reset(&buf);
434 strbuf_addf(&buf, "Subproject commit %s",
435 oid_to_hex(&loid));
436 add_left_or_right(&submodules, src_path, buf.buf, 0);
437 strbuf_reset(&buf);
438 strbuf_addf(&buf, "Subproject commit %s",
439 oid_to_hex(&roid));
440 if (oideq(&loid, &roid))
441 strbuf_addstr(&buf, "-dirty");
442 add_left_or_right(&submodules, dst_path, buf.buf, 1);
443 continue;
444 }
445 if (S_ISLNK(lmode)) {
447 char *content = get_symlink(&loid, src_path);
448 add_left_or_right(&symlinks2, src_path, content, 0);
449 free(content);
450 }
451 if (S_ISLNK(rmode)) {
453 char *content = get_symlink(&roid, dst_path);
454 add_left_or_right(&symlinks2, dst_path, content, 1);
455 free(content);
456 }
457 if (lmode && status != 'C') {
459 if (checkout_path(lmode, &loid, src_path, &lstate)) {
460 ret = error("could not write '%s'", src_path);
461 goto finish;
462 }
463 }
464 if (rmode && !S_ISLNK(rmode)) {
466 struct working_tree_entry *entry;
467 /* Avoid duplicate working_tree entries */
469 FLEX_ALLOC_STR(entry, path, dst_path);
470 hashmap_entry_init(entry, strhash(dst_path));
471 if (hashmap_get(&working_tree_dups, entry, NULL)) {
472 free(entry);
473 continue;
474 }
475 hashmap_add(&working_tree_dups, entry);
476 if (!use_wt_file(workdir, dst_path, &roid)) {
478 if (checkout_path(rmode, &roid, dst_path,
479 &rstate)) {
480 ret = error("could not write '%s'",
481 dst_path);
482 goto finish;
483 }
484 } else if (!is_null_oid(&roid)) {
485 /*
486 * Changes in the working tree need special
487 * treatment since they are not part of the
488 * index.
489 */
490 struct cache_entry *ce2 =
491 make_cache_entry(&wtindex, rmode, &roid,
492 dst_path, 0, 0);
493 add_index_entry(&wtindex, ce2,
495 ADD_CACHE_JUST_APPEND);
496 add_path(&rdir, rdir_len, dst_path);
498 if (ensure_leading_directories(rdir.buf)) {
499 ret = error("could not create "
500 "directory for '%s'",
501 dst_path);
502 goto finish;
503 }
504 add_path(&wtdir, wtdir_len, dst_path);
505 if (symlinks) {
506 if (symlink(wtdir.buf, rdir.buf)) {
507 ret = error_errno("could not symlink '%s' to '%s'", wtdir.buf, rdir.buf);
508 goto finish;
509 }
510 } else {
511 struct stat st;
512 if (stat(wtdir.buf, &st))
513 st.st_mode = 0644;
514 if (copy_file(rdir.buf, wtdir.buf,
515 st.st_mode)) {
516 ret = error("could not copy '%s' to '%s'", wtdir.buf, rdir.buf);
517 goto finish;
518 }
519 }
520 }
521 }
522 }
523 fclose(fp);
525 fp = NULL;
526 if (finish_command(&child)) {
527 ret = error("error occurred running diff --raw");
528 goto finish;
529 }
530 if (!i)
532 goto finish;
533 /*
535 * Changes to submodules require special treatment.This loop writes a
536 * temporary file to both the left and right directories to show the
537 * change in the recorded SHA1 for the submodule.
538 */
539 hashmap_iter_init(&submodules, &iter);
540 while ((entry = hashmap_iter_next(&iter))) {
541 if (*entry->left) {
542 add_path(&ldir, ldir_len, entry->path);
543 ensure_leading_directories(ldir.buf);
544 write_file(ldir.buf, "%s", entry->left);
545 }
546 if (*entry->right) {
547 add_path(&rdir, rdir_len, entry->path);
548 ensure_leading_directories(rdir.buf);
549 write_file(rdir.buf, "%s", entry->right);
550 }
551 }
552 /*
554 * Symbolic links require special treatment.The standard "git diff"
555 * shows only the link itself, not the contents of the link target.
556 * This loop replicates that behavior.
557 */
558 hashmap_iter_init(&symlinks2, &iter);
559 while ((entry = hashmap_iter_next(&iter))) {
560 if (*entry->left) {
561 add_path(&ldir, ldir_len, entry->path);
562 ensure_leading_directories(ldir.buf);
563 write_file(ldir.buf, "%s", entry->left);
564 }
565 if (*entry->right) {
566 add_path(&rdir, rdir_len, entry->path);
567 ensure_leading_directories(rdir.buf);
568 write_file(rdir.buf, "%s", entry->right);
569 }
570 }
571 strbuf_release(&buf);
573 strbuf_setlen(&ldir, ldir_len);
575 helper_argv[1] = ldir.buf;
576 strbuf_setlen(&rdir, rdir_len);
577 helper_argv[2] = rdir.buf;
578 if (extcmd) {
580 helper_argv[0] = extcmd;
581 flags = 0;
582 } else
583 setenv("GIT_DIFFTOOL_DIRDIFF", "true", 1);
584 rc = run_command_v_opt(helper_argv, flags);
585 /*
587 * If the diff includes working copy files and those
588 * files were modified during the diff, then the changes
589 * should be copied back to the working tree.
590 * Do not copy back files when symlinks are used and the
591 * external tool did not replace the original link with a file.
592 *
593 * These hashes are loaded lazily since they aren't needed
594 * in the common case of --symlinks and the difftool updating
595 * files through the symlink.
596 */
597 hashmap_init(&wt_modified, path_entry_cmp, NULL, wtindex.cache_nr);
598 hashmap_init(&tmp_modified, path_entry_cmp, NULL, wtindex.cache_nr);
599 for (i = 0; i < wtindex.cache_nr; i++) {
601 struct hashmap_entry dummy;
602 const char *name = wtindex.cache[i]->name;
603 struct stat st;
604 add_path(&rdir, rdir_len, name);
606 if (lstat(rdir.buf, &st))
607 continue;
608 if ((symlinks && S_ISLNK(st.st_mode)) || !S_ISREG(st.st_mode))
610 continue;
611 if (!indices_loaded) {
613 struct lock_file lock = LOCK_INIT;
614 strbuf_reset(&buf);
615 strbuf_addf(&buf, "%s/wtindex", tmpdir);
616 if (hold_lock_file_for_update(&lock, buf.buf, 0) < 0 ||
617 write_locked_index(&wtindex, &lock, COMMIT_LOCK)) {
618 ret = error("could not write %s", buf.buf);
619 goto finish;
620 }
621 changed_files(&wt_modified, buf.buf, workdir);
622 strbuf_setlen(&rdir, rdir_len);
623 changed_files(&tmp_modified, buf.buf, rdir.buf);
624 add_path(&rdir, rdir_len, name);
625 indices_loaded = 1;
626 }
627 hashmap_entry_init(&dummy, strhash(name));
629 if (hashmap_get(&tmp_modified, &dummy, name)) {
630 add_path(&wtdir, wtdir_len, name);
631 if (hashmap_get(&wt_modified, &dummy, name)) {
632 warning(_("both files modified: '%s' and '%s'."),
633 wtdir.buf, rdir.buf);
634 warning(_("working tree file has been left."));
635 warning("%s", "");
636 err = 1;
637 } else if (unlink(wtdir.buf) ||
638 copy_file(wtdir.buf, rdir.buf, st.st_mode))
639 warning_errno(_("could not copy '%s' to '%s'"),
640 rdir.buf, wtdir.buf);
641 }
642 }
643 if (err) {
645 warning(_("temporary files exist in '%s'."), tmpdir);
646 warning(_("you may want to cleanup or recover these."));
647 exit(1);
648 } else
649 exit_cleanup(tmpdir, rc);
650finish:
652 if (fp)
653 fclose(fp);
654 free(lbase_dir);
656 free(rbase_dir);
657 strbuf_release(&ldir);
658 strbuf_release(&rdir);
659 strbuf_release(&wtdir);
660 strbuf_release(&buf);
661 return ret;
663}
664static int run_file_diff(int prompt, const char *prefix,
666 int argc, const char **argv)
667{
668 struct argv_array args = ARGV_ARRAY_INIT;
669 const char *env[] = {
670 "GIT_PAGER=", "GIT_EXTERNAL_DIFF=git-difftool--helper", NULL,
671 NULL
672 };
673 int ret = 0, i;
674 if (prompt > 0)
676 env[2] = "GIT_DIFFTOOL_PROMPT=true";
677 else if (!prompt)
678 env[2] = "GIT_DIFFTOOL_NO_PROMPT=true";
679 argv_array_push(&args, "diff");
682 for (i = 0; i < argc; i++)
683 argv_array_push(&args, argv[i]);
684 ret = run_command_v_opt_cd_env(args.argv, RUN_GIT_CMD, prefix, env);
685 exit(ret);
686}
687int cmd_difftool(int argc, const char **argv, const char *prefix)
689{
690 int use_gui_tool = 0, dir_diff = 0, prompt = -1, symlinks = 0,
691 tool_help = 0, no_index = 0;
692 static char *difftool_cmd = NULL, *extcmd = NULL;
693 struct option builtin_difftool_options[] = {
694 OPT_BOOL('g', "gui", &use_gui_tool,
695 N_("use `diff.guitool` instead of `diff.tool`")),
696 OPT_BOOL('d', "dir-diff", &dir_diff,
697 N_("perform a full-directory diff")),
698 OPT_SET_INT_F('y', "no-prompt", &prompt,
699 N_("do not prompt before launching a diff tool"),
700 0, PARSE_OPT_NONEG),
701 OPT_SET_INT_F(0, "prompt", &prompt, NULL,
702 1, PARSE_OPT_NONEG | PARSE_OPT_HIDDEN),
703 OPT_BOOL(0, "symlinks", &symlinks,
704 N_("use symlinks in dir-diff mode")),
705 OPT_STRING('t', "tool", &difftool_cmd, N_("tool"),
706 N_("use the specified diff tool")),
707 OPT_BOOL(0, "tool-help", &tool_help,
708 N_("print a list of diff tools that may be used with "
709 "`--tool`")),
710 OPT_BOOL(0, "trust-exit-code", &trust_exit_code,
711 N_("make 'git-difftool' exit when an invoked diff "
712 "tool returns a non - zero exit code")),
713 OPT_STRING('x', "extcmd", &extcmd, N_("command"),
714 N_("specify a custom command for viewing diffs")),
715 OPT_ARGUMENT("no-index", &no_index, N_("passed to `diff`")),
716 OPT_END()
717 };
718 git_config(difftool_config, NULL);
720 symlinks = has_symlinks;
721 argc = parse_options(argc, argv, prefix, builtin_difftool_options,
723 builtin_difftool_usage, PARSE_OPT_KEEP_UNKNOWN |
724 PARSE_OPT_KEEP_DASHDASH);
725 if (tool_help)
727 return print_tool_help();
728 if (!no_index && !startup_info->have_repository)
730 die(_("difftool requires worktree or --no-index"));
731 if (!no_index){
733 setup_work_tree();
734 setenv(GIT_DIR_ENVIRONMENT, absolute_path(get_git_dir()), 1);
735 setenv(GIT_WORK_TREE_ENVIRONMENT, absolute_path(get_git_work_tree()), 1);
736 }
737 if (use_gui_tool && diff_gui_tool && *diff_gui_tool)
739 setenv("GIT_DIFF_TOOL", diff_gui_tool, 1);
740 else if (difftool_cmd) {
741 if (*difftool_cmd)
742 setenv("GIT_DIFF_TOOL", difftool_cmd, 1);
743 else
744 die(_("no <tool> given for --tool=<tool>"));
745 }
746 if (extcmd) {
748 if (*extcmd)
749 setenv("GIT_DIFFTOOL_EXTCMD", extcmd, 1);
750 else
751 die(_("no <cmd> given for --extcmd=<cmd>"));
752 }
753 setenv("GIT_DIFFTOOL_TRUST_EXIT_CODE",
755 trust_exit_code ? "true" : "false", 1);
756 /*
758 * In directory diff mode, 'git-difftool--helper' is called once
759 * to compare the a / b directories. In file diff mode, 'git diff'
760 * will invoke a separate instance of 'git-difftool--helper' for
761 * each file that changed.
762 */
763 if (dir_diff)
764 return run_dir_diff(extcmd, symlinks, prefix, argc, argv);
765 return run_file_diff(prompt, prefix, argc, argv);
766}