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#include "cache.h"
15#include "builtin.h"
16#include "run-command.h"
17#include "exec_cmd.h"
18#include "parse-options.h"
19#include "argv-array.h"
20#include "strbuf.h"
21#include "lockfile.h"
22#include "dir.h"
23static char *diff_gui_tool;
25static int trust_exit_code;
26static const char *const builtin_difftool_usage[] = {
28 N_("git difftool [<options>] [<commit> [<commit>]] [--] [<path>...]"),
29 NULL
30};
31static int difftool_config(const char *var, const char *value, void *cb)
33{
34 if (!strcmp(var, "diff.guitool")) {
35 diff_gui_tool = xstrdup(value);
36 return 0;
37 }
38 if (!strcmp(var, "difftool.trustexitcode")) {
40 trust_exit_code = git_config_bool(var, value);
41 return 0;
42 }
43 return git_default_config(var, value, cb);
45}
46static int print_tool_help(void)
48{
49 const char *argv[] = { "mergetool", "--tool-help=diff", NULL };
50 return run_command_v_opt(argv, RUN_GIT_CMD);
51}
52static int parse_index_info(char *p, int *mode1, int *mode2,
54 struct object_id *oid1, struct object_id *oid2,
55 char *status)
56{
57 if (*p != ':')
58 return error("expected ':', got '%c'", *p);
59 *mode1 = (int)strtol(p + 1, &p, 8);
60 if (*p != ' ')
61 return error("expected ' ', got '%c'", *p);
62 *mode2 = (int)strtol(p + 1, &p, 8);
63 if (*p != ' ')
64 return error("expected ' ', got '%c'", *p);
65 if (get_oid_hex(++p, oid1))
66 return error("expected object ID, got '%s'", p + 1);
67 p += GIT_SHA1_HEXSZ;
68 if (*p != ' ')
69 return error("expected ' ', got '%c'", *p);
70 if (get_oid_hex(++p, oid2))
71 return error("expected object ID, got '%s'", p + 1);
72 p += GIT_SHA1_HEXSZ;
73 if (*p != ' ')
74 return error("expected ' ', got '%c'", *p);
75 *status = *++p;
76 if (!*status)
77 return error("missing status");
78 if (p[1] && !isdigit(p[1]))
79 return error("unexpected trailer: '%s'", p + 1);
80 return 0;
81}
82/*
84 * Remove any trailing slash from $workdir
85 * before starting to avoid double slashes in symlink targets.
86 */
87static void add_path(struct strbuf *buf, size_t base_len, const char *path)
88{
89 strbuf_setlen(buf, base_len);
90 if (buf->len && buf->buf[buf->len - 1] != '/')
91 strbuf_addch(buf, '/');
92 strbuf_addstr(buf, path);
93}
94/*
96 * Determine whether we can simply reuse the file in the worktree.
97 */
98static int use_wt_file(const char *workdir, const char *name,
99 struct object_id *oid)
100{
101 struct strbuf buf = STRBUF_INIT;
102 struct stat st;
103 int use = 0;
104 strbuf_addstr(&buf, workdir);
106 add_path(&buf, buf.len, name);
107 if (!lstat(buf.buf, &st) && !S_ISLNK(st.st_mode)) {
109 struct object_id wt_oid;
110 int fd = open(buf.buf, O_RDONLY);
111 if (fd >= 0 &&
113 !index_fd(wt_oid.hash, fd, &st, OBJ_BLOB, name, 0)) {
114 if (is_null_oid(oid)) {
115 oidcpy(oid, &wt_oid);
116 use = 1;
117 } else if (!oidcmp(oid, &wt_oid))
118 use = 1;
119 }
120 }
121 strbuf_release(&buf);
123 return use;
125}
126struct working_tree_entry {
128 struct hashmap_entry entry;
129 char path[FLEX_ARRAY];
130};
131static int working_tree_entry_cmp(struct working_tree_entry *a,
133 struct working_tree_entry *b, void *keydata)
134{
135 return strcmp(a->path, b->path);
136}
137/*
139 * The `left` and `right` entries hold paths for the symlinks hashmap,
140 * and a SHA-1 surrounded by brief text for submodules.
141 */
142struct pair_entry {
143 struct hashmap_entry entry;
144 char left[PATH_MAX], right[PATH_MAX];
145 const char path[FLEX_ARRAY];
146};
147static int pair_cmp(struct pair_entry *a, struct pair_entry *b, void *keydata)
149{
150 return strcmp(a->path, b->path);
151}
152static void add_left_or_right(struct hashmap *map, const char *path,
154 const char *content, int is_right)
155{
156 struct pair_entry *e, *existing;
157 FLEX_ALLOC_STR(e, path, path);
159 hashmap_entry_init(e, strhash(path));
160 existing = hashmap_get(map, e, NULL);
161 if (existing) {
162 free(e);
163 e = existing;
164 } else {
165 e->left[0] = e->right[0] = '\0';
166 hashmap_add(map, e);
167 }
168 strlcpy(is_right ? e->right : e->left, content, PATH_MAX);
169}
170struct path_entry {
172 struct hashmap_entry entry;
173 char path[FLEX_ARRAY];
174};
175static int path_entry_cmp(struct path_entry *a, struct path_entry *b, void *key)
177{
178 return strcmp(a->path, key ? key : b->path);
179}
180static void changed_files(struct hashmap *result, const char *index_path,
182 const char *workdir)
183{
184 struct child_process update_index = CHILD_PROCESS_INIT;
185 struct child_process diff_files = CHILD_PROCESS_INIT;
186 struct strbuf index_env = STRBUF_INIT, buf = STRBUF_INIT;
187 const char *git_dir = absolute_path(get_git_dir()), *env[] = {
188 NULL, NULL
189 };
190 FILE *fp;
191 strbuf_addf(&index_env, "GIT_INDEX_FILE=%s", index_path);
193 env[0] = index_env.buf;
194 argv_array_pushl(&update_index.args,
196 "--git-dir", git_dir, "--work-tree", workdir,
197 "update-index", "--really-refresh", "-q",
198 "--unmerged", NULL);
199 update_index.no_stdin = 1;
200 update_index.no_stdout = 1;
201 update_index.no_stderr = 1;
202 update_index.git_cmd = 1;
203 update_index.use_shell = 0;
204 update_index.clean_on_exit = 1;
205 update_index.dir = workdir;
206 update_index.env = env;
207 /* Ignore any errors of update-index */
208 run_command(&update_index);
209 argv_array_pushl(&diff_files.args,
211 "--git-dir", git_dir, "--work-tree", workdir,
212 "diff-files", "--name-only", "-z", NULL);
213 diff_files.no_stdin = 1;
214 diff_files.git_cmd = 1;
215 diff_files.use_shell = 0;
216 diff_files.clean_on_exit = 1;
217 diff_files.out = -1;
218 diff_files.dir = workdir;
219 diff_files.env = env;
220 if (start_command(&diff_files))
221 die("could not obtain raw diff");
222 fp = xfdopen(diff_files.out, "r");
223 while (!strbuf_getline_nul(&buf, fp)) {
224 struct path_entry *entry;
225 FLEX_ALLOC_STR(entry, path, buf.buf);
226 hashmap_entry_init(entry, strhash(buf.buf));
227 hashmap_add(result, entry);
228 }
229 if (finish_command(&diff_files))
230 die("diff-files did not exit properly");
231 strbuf_release(&index_env);
232 strbuf_release(&buf);
233}
234static NORETURN void exit_cleanup(const char *tmpdir, int exit_code)
236{
237 struct strbuf buf = STRBUF_INIT;
238 strbuf_addstr(&buf, tmpdir);
239 remove_dir_recursively(&buf, 0);
240 if (exit_code)
241 warning(_("failed: %d"), exit_code);
242 exit(exit_code);
243}
244static int ensure_leading_directories(char *path)
246{
247 switch (safe_create_leading_directories(path)) {
248 case SCLD_OK:
249 case SCLD_EXISTS:
250 return 0;
251 default:
252 return error(_("could not create leading directories "
253 "of '%s'"), path);
254 }
255}
256/*
258 * Unconditional writing of a plain regular file is what
259 * "git difftool --dir-diff" wants to do for symlinks. We are preparing two
260 * temporary directories to be fed to a Git-unaware tool that knows how to
261 * show a diff of two directories (e.g. "diff -r A B").
262 *
263 * Because the tool is Git-unaware, if a symbolic link appears in either of
264 * these temporary directories, it will try to dereference and show the
265 * difference of the target of the symbolic link, which is not what we want,
266 * as the goal of the dir-diff mode is to produce an output that is logically
267 * equivalent to what "git diff" produces.
268 *
269 * Most importantly, we want to get textual comparison of the result of the
270 * readlink(2). get_symlink() provides that---it returns the contents of
271 * the symlink that gets written to a regular file to force the external tool
272 * to compare the readlink(2) result as text, even on a filesystem that is
273 * capable of doing a symbolic link.
274 */
275static char *get_symlink(const struct object_id *oid, const char *path)
276{
277 char *data;
278 if (is_null_oid(oid)) {
279 /* The symlink is unknown to Git so read from the filesystem */
280 struct strbuf link = STRBUF_INIT;
281 if (has_symlinks) {
282 if (strbuf_readlink(&link, path, strlen(path)))
283 die(_("could not read symlink %s"), path);
284 } else if (strbuf_read_file(&link, path, 128))
285 die(_("could not read symlink file %s"), path);
286 data = strbuf_detach(&link, NULL);
288 } else {
289 enum object_type type;
290 unsigned long size;
291 data = read_sha1_file(oid->hash, &type, &size);
292 if (!data)
293 die(_("could not read object %s for symlink %s"),
294 oid_to_hex(oid), path);
295 }
296 return data;
298}
299static int checkout_path(unsigned mode, struct object_id *oid,
301 const char *path, const struct checkout *state)
302{
303 struct cache_entry *ce;
304 int ret;
305 ce = make_cache_entry(mode, oid->hash, path, 0, 0);
307 ret = checkout_entry(ce, state, NULL);
308 free(ce);
310 return ret;
311}
312static int run_dir_diff(const char *extcmd, int symlinks, const char *prefix,
314 int argc, const char **argv)
315{
316 char tmpdir[PATH_MAX];
317 struct strbuf info = STRBUF_INIT, lpath = STRBUF_INIT;
318 struct strbuf rpath = STRBUF_INIT, buf = STRBUF_INIT;
319 struct strbuf ldir = STRBUF_INIT, rdir = STRBUF_INIT;
320 struct strbuf wtdir = STRBUF_INIT;
321 size_t ldir_len, rdir_len, wtdir_len;
322 const char *workdir, *tmp;
323 int ret = 0, i;
324 FILE *fp;
325 struct hashmap working_tree_dups, submodules, symlinks2;
326 struct hashmap_iter iter;
327 struct pair_entry *entry;
328 struct index_state wtindex;
329 struct checkout lstate, rstate;
330 int rc, flags = RUN_GIT_CMD, err = 0;
331 struct child_process child = CHILD_PROCESS_INIT;
332 const char *helper_argv[] = { "difftool--helper", NULL, NULL, NULL };
333 struct hashmap wt_modified, tmp_modified;
334 int indices_loaded = 0;
335 workdir = get_git_work_tree();
337 /* Setup temp directories */
339 tmp = getenv("TMPDIR");
340 xsnprintf(tmpdir, sizeof(tmpdir), "%s/git-difftool.XXXXXX", tmp ? tmp : "/tmp");
341 if (!mkdtemp(tmpdir))
342 return error("could not create '%s'", tmpdir);
343 strbuf_addf(&ldir, "%s/left/", tmpdir);
344 strbuf_addf(&rdir, "%s/right/", tmpdir);
345 strbuf_addstr(&wtdir, workdir);
346 if (!wtdir.len || !is_dir_sep(wtdir.buf[wtdir.len - 1]))
347 strbuf_addch(&wtdir, '/');
348 mkdir(ldir.buf, 0700);
349 mkdir(rdir.buf, 0700);
350 memset(&wtindex, 0, sizeof(wtindex));
352 memset(&lstate, 0, sizeof(lstate));
354 lstate.base_dir = ldir.buf;
355 lstate.base_dir_len = ldir.len;
356 lstate.force = 1;
357 memset(&rstate, 0, sizeof(rstate));
358 rstate.base_dir = rdir.buf;
359 rstate.base_dir_len = rdir.len;
360 rstate.force = 1;
361 ldir_len = ldir.len;
363 rdir_len = rdir.len;
364 wtdir_len = wtdir.len;
365 hashmap_init(&working_tree_dups,
367 (hashmap_cmp_fn)working_tree_entry_cmp, 0);
368 hashmap_init(&submodules, (hashmap_cmp_fn)pair_cmp, 0);
369 hashmap_init(&symlinks2, (hashmap_cmp_fn)pair_cmp, 0);
370 child.no_stdin = 1;
372 child.git_cmd = 1;
373 child.use_shell = 0;
374 child.clean_on_exit = 1;
375 child.dir = prefix;
376 child.out = -1;
377 argv_array_pushl(&child.args, "diff", "--raw", "--no-abbrev", "-z",
378 NULL);
379 for (i = 0; i < argc; i++)
380 argv_array_push(&child.args, argv[i]);
381 if (start_command(&child))
382 die("could not obtain raw diff");
383 fp = xfdopen(child.out, "r");
384 /* Build index info for left and right sides of the diff */
386 i = 0;
387 while (!strbuf_getline_nul(&info, fp)) {
388 int lmode, rmode;
389 struct object_id loid, roid;
390 char status;
391 const char *src_path, *dst_path;
392 if (starts_with(info.buf, "::"))
394 die(N_("combined diff formats('-c' and '--cc') are "
395 "not supported in\n"
396 "directory diff mode('-d' and '--dir-diff')."));
397 if (parse_index_info(info.buf, &lmode, &rmode, &loid, &roid,
399 &status))
400 break;
401 if (strbuf_getline_nul(&lpath, fp))
402 break;
403 src_path = lpath.buf;
404 i++;
406 if (status != 'C' && status != 'R') {
407 dst_path = src_path;
408 } else {
409 if (strbuf_getline_nul(&rpath, fp))
410 break;
411 dst_path = rpath.buf;
412 }
413 if (S_ISGITLINK(lmode) || S_ISGITLINK(rmode)) {
415 strbuf_reset(&buf);
416 strbuf_addf(&buf, "Subproject commit %s",
417 oid_to_hex(&loid));
418 add_left_or_right(&submodules, src_path, buf.buf, 0);
419 strbuf_reset(&buf);
420 strbuf_addf(&buf, "Subproject commit %s",
421 oid_to_hex(&roid));
422 if (!oidcmp(&loid, &roid))
423 strbuf_addstr(&buf, "-dirty");
424 add_left_or_right(&submodules, dst_path, buf.buf, 1);
425 continue;
426 }
427 if (S_ISLNK(lmode)) {
429 char *content = get_symlink(&loid, src_path);
430 add_left_or_right(&symlinks2, src_path, content, 0);
431 free(content);
432 }
433 if (S_ISLNK(rmode)) {
435 char *content = get_symlink(&roid, dst_path);
436 add_left_or_right(&symlinks2, dst_path, content, 1);
437 free(content);
438 }
439 if (lmode && status != 'C') {
441 if (checkout_path(lmode, &loid, src_path, &lstate))
442 return error("could not write '%s'", src_path);
443 }
444 if (rmode && !S_ISLNK(rmode)) {
446 struct working_tree_entry *entry;
447 /* Avoid duplicate working_tree entries */
449 FLEX_ALLOC_STR(entry, path, dst_path);
450 hashmap_entry_init(entry, strhash(dst_path));
451 if (hashmap_get(&working_tree_dups, entry, NULL)) {
452 free(entry);
453 continue;
454 }
455 hashmap_add(&working_tree_dups, entry);
456 if (!use_wt_file(workdir, dst_path, &roid)) {
458 if (checkout_path(rmode, &roid, dst_path, &rstate))
459 return error("could not write '%s'",
460 dst_path);
461 } else if (!is_null_oid(&roid)) {
462 /*
463 * Changes in the working tree need special
464 * treatment since they are not part of the
465 * index.
466 */
467 struct cache_entry *ce2 =
468 make_cache_entry(rmode, roid.hash,
469 dst_path, 0, 0);
470 add_index_entry(&wtindex, ce2,
472 ADD_CACHE_JUST_APPEND);
473 add_path(&rdir, rdir_len, dst_path);
475 if (ensure_leading_directories(rdir.buf))
476 return error("could not create "
477 "directory for '%s'",
478 dst_path);
479 add_path(&wtdir, wtdir_len, dst_path);
480 if (symlinks) {
481 if (symlink(wtdir.buf, rdir.buf)) {
482 ret = error_errno("could not symlink '%s' to '%s'", wtdir.buf, rdir.buf);
483 goto finish;
484 }
485 } else {
486 struct stat st;
487 if (stat(wtdir.buf, &st))
488 st.st_mode = 0644;
489 if (copy_file(rdir.buf, wtdir.buf,
490 st.st_mode)) {
491 ret = error("could not copy '%s' to '%s'", wtdir.buf, rdir.buf);
492 goto finish;
493 }
494 }
495 }
496 }
497 }
498 if (finish_command(&child)) {
500 ret = error("error occurred running diff --raw");
501 goto finish;
502 }
503 if (!i)
505 return 0;
506 /*
508 * Changes to submodules require special treatment.This loop writes a
509 * temporary file to both the left and right directories to show the
510 * change in the recorded SHA1 for the submodule.
511 */
512 hashmap_iter_init(&submodules, &iter);
513 while ((entry = hashmap_iter_next(&iter))) {
514 if (*entry->left) {
515 add_path(&ldir, ldir_len, entry->path);
516 ensure_leading_directories(ldir.buf);
517 write_file(ldir.buf, "%s", entry->left);
518 }
519 if (*entry->right) {
520 add_path(&rdir, rdir_len, entry->path);
521 ensure_leading_directories(rdir.buf);
522 write_file(rdir.buf, "%s", entry->right);
523 }
524 }
525 /*
527 * Symbolic links require special treatment.The standard "git diff"
528 * shows only the link itself, not the contents of the link target.
529 * This loop replicates that behavior.
530 */
531 hashmap_iter_init(&symlinks2, &iter);
532 while ((entry = hashmap_iter_next(&iter))) {
533 if (*entry->left) {
534 add_path(&ldir, ldir_len, entry->path);
535 ensure_leading_directories(ldir.buf);
536 write_file(ldir.buf, "%s", entry->left);
537 }
538 if (*entry->right) {
539 add_path(&rdir, rdir_len, entry->path);
540 ensure_leading_directories(rdir.buf);
541 write_file(rdir.buf, "%s", entry->right);
542 }
543 }
544 strbuf_release(&buf);
546 strbuf_setlen(&ldir, ldir_len);
548 helper_argv[1] = ldir.buf;
549 strbuf_setlen(&rdir, rdir_len);
550 helper_argv[2] = rdir.buf;
551 if (extcmd) {
553 helper_argv[0] = extcmd;
554 flags = 0;
555 } else
556 setenv("GIT_DIFFTOOL_DIRDIFF", "true", 1);
557 rc = run_command_v_opt(helper_argv, flags);
558 /*
560 * If the diff includes working copy files and those
561 * files were modified during the diff, then the changes
562 * should be copied back to the working tree.
563 * Do not copy back files when symlinks are used and the
564 * external tool did not replace the original link with a file.
565 *
566 * These hashes are loaded lazily since they aren't needed
567 * in the common case of --symlinks and the difftool updating
568 * files through the symlink.
569 */
570 hashmap_init(&wt_modified, (hashmap_cmp_fn)path_entry_cmp,
571 wtindex.cache_nr);
572 hashmap_init(&tmp_modified, (hashmap_cmp_fn)path_entry_cmp,
573 wtindex.cache_nr);
574 for (i = 0; i < wtindex.cache_nr; i++) {
576 struct hashmap_entry dummy;
577 const char *name = wtindex.cache[i]->name;
578 struct stat st;
579 add_path(&rdir, rdir_len, name);
581 if (lstat(rdir.buf, &st))
582 continue;
583 if ((symlinks && S_ISLNK(st.st_mode)) || !S_ISREG(st.st_mode))
585 continue;
586 if (!indices_loaded) {
588 static struct lock_file lock;
589 strbuf_reset(&buf);
590 strbuf_addf(&buf, "%s/wtindex", tmpdir);
591 if (hold_lock_file_for_update(&lock, buf.buf, 0) < 0 ||
592 write_locked_index(&wtindex, &lock, COMMIT_LOCK)) {
593 ret = error("could not write %s", buf.buf);
594 rollback_lock_file(&lock);
595 goto finish;
596 }
597 changed_files(&wt_modified, buf.buf, workdir);
598 strbuf_setlen(&rdir, rdir_len);
599 changed_files(&tmp_modified, buf.buf, rdir.buf);
600 add_path(&rdir, rdir_len, name);
601 indices_loaded = 1;
602 }
603 hashmap_entry_init(&dummy, strhash(name));
605 if (hashmap_get(&tmp_modified, &dummy, name)) {
606 add_path(&wtdir, wtdir_len, name);
607 if (hashmap_get(&wt_modified, &dummy, name)) {
608 warning(_("both files modified: '%s' and '%s'."),
609 wtdir.buf, rdir.buf);
610 warning(_("working tree file has been left."));
611 warning("%s", "");
612 err = 1;
613 } else if (unlink(wtdir.buf) ||
614 copy_file(wtdir.buf, rdir.buf, st.st_mode))
615 warning_errno(_("could not copy '%s' to '%s'"),
616 rdir.buf, wtdir.buf);
617 }
618 }
619 if (err) {
621 warning(_("temporary files exist in '%s'."), tmpdir);
622 warning(_("you may want to cleanup or recover these."));
623 exit(1);
624 } else
625 exit_cleanup(tmpdir, rc);
626finish:
628 strbuf_release(&ldir);
629 strbuf_release(&rdir);
630 strbuf_release(&wtdir);
631 strbuf_release(&buf);
632 return ret;
634}
635static int run_file_diff(int prompt, const char *prefix,
637 int argc, const char **argv)
638{
639 struct argv_array args = ARGV_ARRAY_INIT;
640 const char *env[] = {
641 "GIT_PAGER=", "GIT_EXTERNAL_DIFF=git-difftool--helper", NULL,
642 NULL
643 };
644 int ret = 0, i;
645 if (prompt > 0)
647 env[2] = "GIT_DIFFTOOL_PROMPT=true";
648 else if (!prompt)
649 env[2] = "GIT_DIFFTOOL_NO_PROMPT=true";
650 argv_array_push(&args, "diff");
653 for (i = 0; i < argc; i++)
654 argv_array_push(&args, argv[i]);
655 ret = run_command_v_opt_cd_env(args.argv, RUN_GIT_CMD, prefix, env);
656 exit(ret);
657}
658int cmd_difftool(int argc, const char **argv, const char *prefix)
660{
661 int use_gui_tool = 0, dir_diff = 0, prompt = -1, symlinks = 0,
662 tool_help = 0;
663 static char *difftool_cmd = NULL, *extcmd = NULL;
664 struct option builtin_difftool_options[] = {
665 OPT_BOOL('g', "gui", &use_gui_tool,
666 N_("use `diff.guitool` instead of `diff.tool`")),
667 OPT_BOOL('d', "dir-diff", &dir_diff,
668 N_("perform a full-directory diff")),
669 { OPTION_SET_INT, 'y', "no-prompt", &prompt, NULL,
670 N_("do not prompt before launching a diff tool"),
671 PARSE_OPT_NOARG | PARSE_OPT_NONEG, NULL, 0},
672 { OPTION_SET_INT, 0, "prompt", &prompt, NULL, NULL,
673 PARSE_OPT_NOARG | PARSE_OPT_NONEG | PARSE_OPT_HIDDEN,
674 NULL, 1 },
675 OPT_BOOL(0, "symlinks", &symlinks,
676 N_("use symlinks in dir-diff mode")),
677 OPT_STRING('t', "tool", &difftool_cmd, N_("<tool>"),
678 N_("use the specified diff tool")),
679 OPT_BOOL(0, "tool-help", &tool_help,
680 N_("print a list of diff tools that may be used with "
681 "`--tool`")),
682 OPT_BOOL(0, "trust-exit-code", &trust_exit_code,
683 N_("make 'git-difftool' exit when an invoked diff "
684 "tool returns a non - zero exit code")),
685 OPT_STRING('x', "extcmd", &extcmd, N_("<command>"),
686 N_("specify a custom command for viewing diffs")),
687 OPT_END()
688 };
689 git_config(difftool_config, NULL);
691 symlinks = has_symlinks;
692 argc = parse_options(argc, argv, prefix, builtin_difftool_options,
694 builtin_difftool_usage, PARSE_OPT_KEEP_UNKNOWN |
695 PARSE_OPT_KEEP_DASHDASH);
696 if (tool_help)
698 return print_tool_help();
699 /* NEEDSWORK: once we no longer spawn anything, remove this */
701 setenv(GIT_DIR_ENVIRONMENT, absolute_path(get_git_dir()), 1);
702 setenv(GIT_WORK_TREE_ENVIRONMENT, absolute_path(get_git_work_tree()), 1);
703 if (use_gui_tool && diff_gui_tool && *diff_gui_tool)
705 setenv("GIT_DIFF_TOOL", diff_gui_tool, 1);
706 else if (difftool_cmd) {
707 if (*difftool_cmd)
708 setenv("GIT_DIFF_TOOL", difftool_cmd, 1);
709 else
710 die(_("no <tool> given for --tool=<tool>"));
711 }
712 if (extcmd) {
714 if (*extcmd)
715 setenv("GIT_DIFFTOOL_EXTCMD", extcmd, 1);
716 else
717 die(_("no <cmd> given for --extcmd=<cmd>"));
718 }
719 setenv("GIT_DIFFTOOL_TRUST_EXIT_CODE",
721 trust_exit_code ? "true" : "false", 1);
722 /*
724 * In directory diff mode, 'git-difftool--helper' is called once
725 * to compare the a / b directories. In file diff mode, 'git diff'
726 * will invoke a separate instance of 'git-difftool--helper' for
727 * each file that changed.
728 */
729 if (dir_diff)
730 return run_dir_diff(extcmd, symlinks, prefix, argc, argv);
731 return run_file_diff(prompt, prefix, argc, argv);
732}