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 (get_oid_hex(++p, oid1))
69 return error("expected object ID, got '%s'", p + 1);
70 p += GIT_SHA1_HEXSZ;
71 if (*p != ' ')
72 return error("expected ' ', got '%c'", *p);
73 if (get_oid_hex(++p, oid2))
74 return error("expected object ID, got '%s'", p + 1);
75 p += GIT_SHA1_HEXSZ;
76 if (*p != ' ')
77 return error("expected ' ', got '%c'", *p);
78 *status = *++p;
79 if (!*status)
80 return error("missing status");
81 if (p[1] && !isdigit(p[1]))
82 return error("unexpected trailer: '%s'", p + 1);
83 return 0;
84}
85/*
87 * Remove any trailing slash from $workdir
88 * before starting to avoid double slashes in symlink targets.
89 */
90static void add_path(struct strbuf *buf, size_t base_len, const char *path)
91{
92 strbuf_setlen(buf, base_len);
93 if (buf->len && buf->buf[buf->len - 1] != '/')
94 strbuf_addch(buf, '/');
95 strbuf_addstr(buf, path);
96}
97/*
99 * Determine whether we can simply reuse the file in the worktree.
100 */
101static int use_wt_file(const char *workdir, const char *name,
102 struct object_id *oid)
103{
104 struct strbuf buf = STRBUF_INIT;
105 struct stat st;
106 int use = 0;
107 strbuf_addstr(&buf, workdir);
109 add_path(&buf, buf.len, name);
110 if (!lstat(buf.buf, &st) && !S_ISLNK(st.st_mode)) {
112 struct object_id wt_oid;
113 int fd = open(buf.buf, O_RDONLY);
114 if (fd >= 0 &&
116 !index_fd(&the_index, &wt_oid, fd, &st, OBJ_BLOB, name, 0)) {
117 if (is_null_oid(oid)) {
118 oidcpy(oid, &wt_oid);
119 use = 1;
120 } else if (oideq(oid, &wt_oid))
121 use = 1;
122 }
123 }
124 strbuf_release(&buf);
126 return use;
128}
129struct working_tree_entry {
131 struct hashmap_entry entry;
132 char path[FLEX_ARRAY];
133};
134static int working_tree_entry_cmp(const void *unused_cmp_data,
136 const void *entry,
137 const void *entry_or_key,
138 const void *unused_keydata)
139{
140 const struct working_tree_entry *a = entry;
141 const struct working_tree_entry *b = entry_or_key;
142 return strcmp(a->path, b->path);
143}
144/*
146 * The `left` and `right` entries hold paths for the symlinks hashmap,
147 * and a SHA-1 surrounded by brief text for submodules.
148 */
149struct pair_entry {
150 struct hashmap_entry entry;
151 char left[PATH_MAX], right[PATH_MAX];
152 const char path[FLEX_ARRAY];
153};
154static int pair_cmp(const void *unused_cmp_data,
156 const void *entry,
157 const void *entry_or_key,
158 const void *unused_keydata)
159{
160 const struct pair_entry *a = entry;
161 const struct pair_entry *b = entry_or_key;
162 return strcmp(a->path, b->path);
164}
165static void add_left_or_right(struct hashmap *map, const char *path,
167 const char *content, int is_right)
168{
169 struct pair_entry *e, *existing;
170 FLEX_ALLOC_STR(e, path, path);
172 hashmap_entry_init(e, strhash(path));
173 existing = hashmap_get(map, e, NULL);
174 if (existing) {
175 free(e);
176 e = existing;
177 } else {
178 e->left[0] = e->right[0] = '\0';
179 hashmap_add(map, e);
180 }
181 strlcpy(is_right ? e->right : e->left, content, PATH_MAX);
182}
183struct path_entry {
185 struct hashmap_entry entry;
186 char path[FLEX_ARRAY];
187};
188static int path_entry_cmp(const void *unused_cmp_data,
190 const void *entry,
191 const void *entry_or_key,
192 const void *key)
193{
194 const struct path_entry *a = entry;
195 const struct path_entry *b = entry_or_key;
196 return strcmp(a->path, key ? key : b->path);
198}
199static void changed_files(struct hashmap *result, const char *index_path,
201 const char *workdir)
202{
203 struct child_process update_index = CHILD_PROCESS_INIT;
204 struct child_process diff_files = CHILD_PROCESS_INIT;
205 struct strbuf index_env = STRBUF_INIT, buf = STRBUF_INIT;
206 const char *git_dir = absolute_path(get_git_dir()), *env[] = {
207 NULL, NULL
208 };
209 FILE *fp;
210 strbuf_addf(&index_env, "GIT_INDEX_FILE=%s", index_path);
212 env[0] = index_env.buf;
213 argv_array_pushl(&update_index.args,
215 "--git-dir", git_dir, "--work-tree", workdir,
216 "update-index", "--really-refresh", "-q",
217 "--unmerged", NULL);
218 update_index.no_stdin = 1;
219 update_index.no_stdout = 1;
220 update_index.no_stderr = 1;
221 update_index.git_cmd = 1;
222 update_index.use_shell = 0;
223 update_index.clean_on_exit = 1;
224 update_index.dir = workdir;
225 update_index.env = env;
226 /* Ignore any errors of update-index */
227 run_command(&update_index);
228 argv_array_pushl(&diff_files.args,
230 "--git-dir", git_dir, "--work-tree", workdir,
231 "diff-files", "--name-only", "-z", NULL);
232 diff_files.no_stdin = 1;
233 diff_files.git_cmd = 1;
234 diff_files.use_shell = 0;
235 diff_files.clean_on_exit = 1;
236 diff_files.out = -1;
237 diff_files.dir = workdir;
238 diff_files.env = env;
239 if (start_command(&diff_files))
240 die("could not obtain raw diff");
241 fp = xfdopen(diff_files.out, "r");
242 while (!strbuf_getline_nul(&buf, fp)) {
243 struct path_entry *entry;
244 FLEX_ALLOC_STR(entry, path, buf.buf);
245 hashmap_entry_init(entry, strhash(buf.buf));
246 hashmap_add(result, entry);
247 }
248 fclose(fp);
249 if (finish_command(&diff_files))
250 die("diff-files did not exit properly");
251 strbuf_release(&index_env);
252 strbuf_release(&buf);
253}
254static NORETURN void exit_cleanup(const char *tmpdir, int exit_code)
256{
257 struct strbuf buf = STRBUF_INIT;
258 strbuf_addstr(&buf, tmpdir);
259 remove_dir_recursively(&buf, 0);
260 if (exit_code)
261 warning(_("failed: %d"), exit_code);
262 exit(exit_code);
263}
264static int ensure_leading_directories(char *path)
266{
267 switch (safe_create_leading_directories(path)) {
268 case SCLD_OK:
269 case SCLD_EXISTS:
270 return 0;
271 default:
272 return error(_("could not create leading directories "
273 "of '%s'"), path);
274 }
275}
276/*
278 * Unconditional writing of a plain regular file is what
279 * "git difftool --dir-diff" wants to do for symlinks. We are preparing two
280 * temporary directories to be fed to a Git-unaware tool that knows how to
281 * show a diff of two directories (e.g. "diff -r A B").
282 *
283 * Because the tool is Git-unaware, if a symbolic link appears in either of
284 * these temporary directories, it will try to dereference and show the
285 * difference of the target of the symbolic link, which is not what we want,
286 * as the goal of the dir-diff mode is to produce an output that is logically
287 * equivalent to what "git diff" produces.
288 *
289 * Most importantly, we want to get textual comparison of the result of the
290 * readlink(2). get_symlink() provides that---it returns the contents of
291 * the symlink that gets written to a regular file to force the external tool
292 * to compare the readlink(2) result as text, even on a filesystem that is
293 * capable of doing a symbolic link.
294 */
295static char *get_symlink(const struct object_id *oid, const char *path)
296{
297 char *data;
298 if (is_null_oid(oid)) {
299 /* The symlink is unknown to Git so read from the filesystem */
300 struct strbuf link = STRBUF_INIT;
301 if (has_symlinks) {
302 if (strbuf_readlink(&link, path, strlen(path)))
303 die(_("could not read symlink %s"), path);
304 } else if (strbuf_read_file(&link, path, 128))
305 die(_("could not read symlink file %s"), path);
306 data = strbuf_detach(&link, NULL);
308 } else {
309 enum object_type type;
310 unsigned long size;
311 data = read_object_file(oid, &type, &size);
312 if (!data)
313 die(_("could not read object %s for symlink %s"),
314 oid_to_hex(oid), path);
315 }
316 return data;
318}
319static int checkout_path(unsigned mode, struct object_id *oid,
321 const char *path, const struct checkout *state)
322{
323 struct cache_entry *ce;
324 int ret;
325 ce = make_transient_cache_entry(mode, oid, path, 0);
327 ret = checkout_entry(ce, state, NULL, NULL);
328 discard_cache_entry(ce);
330 return ret;
331}
332static int run_dir_diff(const char *extcmd, int symlinks, const char *prefix,
334 int argc, const char **argv)
335{
336 char tmpdir[PATH_MAX];
337 struct strbuf info = STRBUF_INIT, lpath = STRBUF_INIT;
338 struct strbuf rpath = STRBUF_INIT, buf = STRBUF_INIT;
339 struct strbuf ldir = STRBUF_INIT, rdir = STRBUF_INIT;
340 struct strbuf wtdir = STRBUF_INIT;
341 char *lbase_dir, *rbase_dir;
342 size_t ldir_len, rdir_len, wtdir_len;
343 const char *workdir, *tmp;
344 int ret = 0, i;
345 FILE *fp;
346 struct hashmap working_tree_dups, submodules, symlinks2;
347 struct hashmap_iter iter;
348 struct pair_entry *entry;
349 struct index_state wtindex;
350 struct checkout lstate, rstate;
351 int rc, flags = RUN_GIT_CMD, err = 0;
352 struct child_process child = CHILD_PROCESS_INIT;
353 const char *helper_argv[] = { "difftool--helper", NULL, NULL, NULL };
354 struct hashmap wt_modified, tmp_modified;
355 int indices_loaded = 0;
356 workdir = get_git_work_tree();
358 /* Setup temp directories */
360 tmp = getenv("TMPDIR");
361 xsnprintf(tmpdir, sizeof(tmpdir), "%s/git-difftool.XXXXXX", tmp ? tmp : "/tmp");
362 if (!mkdtemp(tmpdir))
363 return error("could not create '%s'", tmpdir);
364 strbuf_addf(&ldir, "%s/left/", tmpdir);
365 strbuf_addf(&rdir, "%s/right/", tmpdir);
366 strbuf_addstr(&wtdir, workdir);
367 if (!wtdir.len || !is_dir_sep(wtdir.buf[wtdir.len - 1]))
368 strbuf_addch(&wtdir, '/');
369 mkdir(ldir.buf, 0700);
370 mkdir(rdir.buf, 0700);
371 memset(&wtindex, 0, sizeof(wtindex));
373 memset(&lstate, 0, sizeof(lstate));
375 lstate.base_dir = lbase_dir = xstrdup(ldir.buf);
376 lstate.base_dir_len = ldir.len;
377 lstate.force = 1;
378 memset(&rstate, 0, sizeof(rstate));
379 rstate.base_dir = rbase_dir = xstrdup(rdir.buf);
380 rstate.base_dir_len = rdir.len;
381 rstate.force = 1;
382 ldir_len = ldir.len;
384 rdir_len = rdir.len;
385 wtdir_len = wtdir.len;
386 hashmap_init(&working_tree_dups, working_tree_entry_cmp, NULL, 0);
388 hashmap_init(&submodules, pair_cmp, NULL, 0);
389 hashmap_init(&symlinks2, pair_cmp, NULL, 0);
390 child.no_stdin = 1;
392 child.git_cmd = 1;
393 child.use_shell = 0;
394 child.clean_on_exit = 1;
395 child.dir = prefix;
396 child.out = -1;
397 argv_array_pushl(&child.args, "diff", "--raw", "--no-abbrev", "-z",
398 NULL);
399 for (i = 0; i < argc; i++)
400 argv_array_push(&child.args, argv[i]);
401 if (start_command(&child))
402 die("could not obtain raw diff");
403 fp = xfdopen(child.out, "r");
404 /* Build index info for left and right sides of the diff */
406 i = 0;
407 while (!strbuf_getline_nul(&info, fp)) {
408 int lmode, rmode;
409 struct object_id loid, roid;
410 char status;
411 const char *src_path, *dst_path;
412 if (starts_with(info.buf, "::"))
414 die(N_("combined diff formats('-c' and '--cc') are "
415 "not supported in\n"
416 "directory diff mode('-d' and '--dir-diff')."));
417 if (parse_index_info(info.buf, &lmode, &rmode, &loid, &roid,
419 &status))
420 break;
421 if (strbuf_getline_nul(&lpath, fp))
422 break;
423 src_path = lpath.buf;
424 i++;
426 if (status != 'C' && status != 'R') {
427 dst_path = src_path;
428 } else {
429 if (strbuf_getline_nul(&rpath, fp))
430 break;
431 dst_path = rpath.buf;
432 }
433 if (S_ISGITLINK(lmode) || S_ISGITLINK(rmode)) {
435 strbuf_reset(&buf);
436 strbuf_addf(&buf, "Subproject commit %s",
437 oid_to_hex(&loid));
438 add_left_or_right(&submodules, src_path, buf.buf, 0);
439 strbuf_reset(&buf);
440 strbuf_addf(&buf, "Subproject commit %s",
441 oid_to_hex(&roid));
442 if (oideq(&loid, &roid))
443 strbuf_addstr(&buf, "-dirty");
444 add_left_or_right(&submodules, dst_path, buf.buf, 1);
445 continue;
446 }
447 if (S_ISLNK(lmode)) {
449 char *content = get_symlink(&loid, src_path);
450 add_left_or_right(&symlinks2, src_path, content, 0);
451 free(content);
452 }
453 if (S_ISLNK(rmode)) {
455 char *content = get_symlink(&roid, dst_path);
456 add_left_or_right(&symlinks2, dst_path, content, 1);
457 free(content);
458 }
459 if (lmode && status != 'C') {
461 if (checkout_path(lmode, &loid, src_path, &lstate)) {
462 ret = error("could not write '%s'", src_path);
463 goto finish;
464 }
465 }
466 if (rmode && !S_ISLNK(rmode)) {
468 struct working_tree_entry *entry;
469 /* Avoid duplicate working_tree entries */
471 FLEX_ALLOC_STR(entry, path, dst_path);
472 hashmap_entry_init(entry, strhash(dst_path));
473 if (hashmap_get(&working_tree_dups, entry, NULL)) {
474 free(entry);
475 continue;
476 }
477 hashmap_add(&working_tree_dups, entry);
478 if (!use_wt_file(workdir, dst_path, &roid)) {
480 if (checkout_path(rmode, &roid, dst_path,
481 &rstate)) {
482 ret = error("could not write '%s'",
483 dst_path);
484 goto finish;
485 }
486 } else if (!is_null_oid(&roid)) {
487 /*
488 * Changes in the working tree need special
489 * treatment since they are not part of the
490 * index.
491 */
492 struct cache_entry *ce2 =
493 make_cache_entry(&wtindex, rmode, &roid,
494 dst_path, 0, 0);
495 add_index_entry(&wtindex, ce2,
497 ADD_CACHE_JUST_APPEND);
498 add_path(&rdir, rdir_len, dst_path);
500 if (ensure_leading_directories(rdir.buf)) {
501 ret = error("could not create "
502 "directory for '%s'",
503 dst_path);
504 goto finish;
505 }
506 add_path(&wtdir, wtdir_len, dst_path);
507 if (symlinks) {
508 if (symlink(wtdir.buf, rdir.buf)) {
509 ret = error_errno("could not symlink '%s' to '%s'", wtdir.buf, rdir.buf);
510 goto finish;
511 }
512 } else {
513 struct stat st;
514 if (stat(wtdir.buf, &st))
515 st.st_mode = 0644;
516 if (copy_file(rdir.buf, wtdir.buf,
517 st.st_mode)) {
518 ret = error("could not copy '%s' to '%s'", wtdir.buf, rdir.buf);
519 goto finish;
520 }
521 }
522 }
523 }
524 }
525 fclose(fp);
527 fp = NULL;
528 if (finish_command(&child)) {
529 ret = error("error occurred running diff --raw");
530 goto finish;
531 }
532 if (!i)
534 goto finish;
535 /*
537 * Changes to submodules require special treatment.This loop writes a
538 * temporary file to both the left and right directories to show the
539 * change in the recorded SHA1 for the submodule.
540 */
541 hashmap_iter_init(&submodules, &iter);
542 while ((entry = hashmap_iter_next(&iter))) {
543 if (*entry->left) {
544 add_path(&ldir, ldir_len, entry->path);
545 ensure_leading_directories(ldir.buf);
546 write_file(ldir.buf, "%s", entry->left);
547 }
548 if (*entry->right) {
549 add_path(&rdir, rdir_len, entry->path);
550 ensure_leading_directories(rdir.buf);
551 write_file(rdir.buf, "%s", entry->right);
552 }
553 }
554 /*
556 * Symbolic links require special treatment.The standard "git diff"
557 * shows only the link itself, not the contents of the link target.
558 * This loop replicates that behavior.
559 */
560 hashmap_iter_init(&symlinks2, &iter);
561 while ((entry = hashmap_iter_next(&iter))) {
562 if (*entry->left) {
563 add_path(&ldir, ldir_len, entry->path);
564 ensure_leading_directories(ldir.buf);
565 write_file(ldir.buf, "%s", entry->left);
566 }
567 if (*entry->right) {
568 add_path(&rdir, rdir_len, entry->path);
569 ensure_leading_directories(rdir.buf);
570 write_file(rdir.buf, "%s", entry->right);
571 }
572 }
573 strbuf_release(&buf);
575 strbuf_setlen(&ldir, ldir_len);
577 helper_argv[1] = ldir.buf;
578 strbuf_setlen(&rdir, rdir_len);
579 helper_argv[2] = rdir.buf;
580 if (extcmd) {
582 helper_argv[0] = extcmd;
583 flags = 0;
584 } else
585 setenv("GIT_DIFFTOOL_DIRDIFF", "true", 1);
586 rc = run_command_v_opt(helper_argv, flags);
587 /*
589 * If the diff includes working copy files and those
590 * files were modified during the diff, then the changes
591 * should be copied back to the working tree.
592 * Do not copy back files when symlinks are used and the
593 * external tool did not replace the original link with a file.
594 *
595 * These hashes are loaded lazily since they aren't needed
596 * in the common case of --symlinks and the difftool updating
597 * files through the symlink.
598 */
599 hashmap_init(&wt_modified, path_entry_cmp, NULL, wtindex.cache_nr);
600 hashmap_init(&tmp_modified, path_entry_cmp, NULL, wtindex.cache_nr);
601 for (i = 0; i < wtindex.cache_nr; i++) {
603 struct hashmap_entry dummy;
604 const char *name = wtindex.cache[i]->name;
605 struct stat st;
606 add_path(&rdir, rdir_len, name);
608 if (lstat(rdir.buf, &st))
609 continue;
610 if ((symlinks && S_ISLNK(st.st_mode)) || !S_ISREG(st.st_mode))
612 continue;
613 if (!indices_loaded) {
615 struct lock_file lock = LOCK_INIT;
616 strbuf_reset(&buf);
617 strbuf_addf(&buf, "%s/wtindex", tmpdir);
618 if (hold_lock_file_for_update(&lock, buf.buf, 0) < 0 ||
619 write_locked_index(&wtindex, &lock, COMMIT_LOCK)) {
620 ret = error("could not write %s", buf.buf);
621 goto finish;
622 }
623 changed_files(&wt_modified, buf.buf, workdir);
624 strbuf_setlen(&rdir, rdir_len);
625 changed_files(&tmp_modified, buf.buf, rdir.buf);
626 add_path(&rdir, rdir_len, name);
627 indices_loaded = 1;
628 }
629 hashmap_entry_init(&dummy, strhash(name));
631 if (hashmap_get(&tmp_modified, &dummy, name)) {
632 add_path(&wtdir, wtdir_len, name);
633 if (hashmap_get(&wt_modified, &dummy, name)) {
634 warning(_("both files modified: '%s' and '%s'."),
635 wtdir.buf, rdir.buf);
636 warning(_("working tree file has been left."));
637 warning("%s", "");
638 err = 1;
639 } else if (unlink(wtdir.buf) ||
640 copy_file(wtdir.buf, rdir.buf, st.st_mode))
641 warning_errno(_("could not copy '%s' to '%s'"),
642 rdir.buf, wtdir.buf);
643 }
644 }
645 if (err) {
647 warning(_("temporary files exist in '%s'."), tmpdir);
648 warning(_("you may want to cleanup or recover these."));
649 exit(1);
650 } else
651 exit_cleanup(tmpdir, rc);
652finish:
654 if (fp)
655 fclose(fp);
656 free(lbase_dir);
658 free(rbase_dir);
659 strbuf_release(&ldir);
660 strbuf_release(&rdir);
661 strbuf_release(&wtdir);
662 strbuf_release(&buf);
663 return ret;
665}
666static int run_file_diff(int prompt, const char *prefix,
668 int argc, const char **argv)
669{
670 struct argv_array args = ARGV_ARRAY_INIT;
671 const char *env[] = {
672 "GIT_PAGER=", "GIT_EXTERNAL_DIFF=git-difftool--helper", NULL,
673 NULL
674 };
675 int ret = 0, i;
676 if (prompt > 0)
678 env[2] = "GIT_DIFFTOOL_PROMPT=true";
679 else if (!prompt)
680 env[2] = "GIT_DIFFTOOL_NO_PROMPT=true";
681 argv_array_push(&args, "diff");
684 for (i = 0; i < argc; i++)
685 argv_array_push(&args, argv[i]);
686 ret = run_command_v_opt_cd_env(args.argv, RUN_GIT_CMD, prefix, env);
687 exit(ret);
688}
689int cmd_difftool(int argc, const char **argv, const char *prefix)
691{
692 int use_gui_tool = 0, dir_diff = 0, prompt = -1, symlinks = 0,
693 tool_help = 0;
694 static char *difftool_cmd = NULL, *extcmd = NULL;
695 struct option builtin_difftool_options[] = {
696 OPT_BOOL('g', "gui", &use_gui_tool,
697 N_("use `diff.guitool` instead of `diff.tool`")),
698 OPT_BOOL('d', "dir-diff", &dir_diff,
699 N_("perform a full-directory diff")),
700 OPT_SET_INT_F('y', "no-prompt", &prompt,
701 N_("do not prompt before launching a diff tool"),
702 0, PARSE_OPT_NONEG),
703 OPT_SET_INT_F(0, "prompt", &prompt, NULL,
704 1, PARSE_OPT_NONEG | PARSE_OPT_HIDDEN),
705 OPT_BOOL(0, "symlinks", &symlinks,
706 N_("use symlinks in dir-diff mode")),
707 OPT_STRING('t', "tool", &difftool_cmd, N_("tool"),
708 N_("use the specified diff tool")),
709 OPT_BOOL(0, "tool-help", &tool_help,
710 N_("print a list of diff tools that may be used with "
711 "`--tool`")),
712 OPT_BOOL(0, "trust-exit-code", &trust_exit_code,
713 N_("make 'git-difftool' exit when an invoked diff "
714 "tool returns a non - zero exit code")),
715 OPT_STRING('x', "extcmd", &extcmd, N_("command"),
716 N_("specify a custom command for viewing diffs")),
717 OPT_END()
718 };
719 git_config(difftool_config, NULL);
721 symlinks = has_symlinks;
722 argc = parse_options(argc, argv, prefix, builtin_difftool_options,
724 builtin_difftool_usage, PARSE_OPT_KEEP_UNKNOWN |
725 PARSE_OPT_KEEP_DASHDASH);
726 if (tool_help)
728 return print_tool_help();
729 /* NEEDSWORK: once we no longer spawn anything, remove this */
731 setenv(GIT_DIR_ENVIRONMENT, absolute_path(get_git_dir()), 1);
732 setenv(GIT_WORK_TREE_ENVIRONMENT, absolute_path(get_git_work_tree()), 1);
733 if (use_gui_tool && diff_gui_tool && *diff_gui_tool)
735 setenv("GIT_DIFF_TOOL", diff_gui_tool, 1);
736 else if (difftool_cmd) {
737 if (*difftool_cmd)
738 setenv("GIT_DIFF_TOOL", difftool_cmd, 1);
739 else
740 die(_("no <tool> given for --tool=<tool>"));
741 }
742 if (extcmd) {
744 if (*extcmd)
745 setenv("GIT_DIFFTOOL_EXTCMD", extcmd, 1);
746 else
747 die(_("no <cmd> given for --extcmd=<cmd>"));
748 }
749 setenv("GIT_DIFFTOOL_TRUST_EXIT_CODE",
751 trust_exit_code ? "true" : "false", 1);
752 /*
754 * In directory diff mode, 'git-difftool--helper' is called once
755 * to compare the a / b directories. In file diff mode, 'git diff'
756 * will invoke a separate instance of 'git-difftool--helper' for
757 * each file that changed.
758 */
759 if (dir_diff)
760 return run_dir_diff(extcmd, symlinks, prefix, argc, argv);
761 return run_file_diff(prompt, prefix, argc, argv);
762}