2 * "git difftool" builtin command
4 * This is a wrapper around the GIT_EXTERNAL_DIFF-compatible
5 * git-difftool--helper script.
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.
10 * Any arguments that are unknown to this script are forwarded to 'git diff'.
12 * Copyright (C) 2016 Johannes Schindelin
17 #include "run-command.h"
19 #include "parse-options.h"
20 #include "argv-array.h"
25 static char *diff_gui_tool
;
26 static int trust_exit_code
;
28 static const char *const builtin_difftool_usage
[] = {
29 N_("git difftool [<options>] [<commit> [<commit>]] [--] [<path>...]"),
33 static int difftool_config(const char *var
, const char *value
, void *cb
)
35 if (!strcmp(var
, "diff.guitool")) {
36 diff_gui_tool
= xstrdup(value
);
40 if (!strcmp(var
, "difftool.trustexitcode")) {
41 trust_exit_code
= git_config_bool(var
, value
);
45 return git_default_config(var
, value
, cb
);
48 static int print_tool_help(void)
50 const char *argv
[] = { "mergetool", "--tool-help=diff", NULL
};
51 return run_command_v_opt(argv
, RUN_GIT_CMD
);
54 static int parse_index_info(char *p
, int *mode1
, int *mode2
,
55 struct object_id
*oid1
, struct object_id
*oid2
,
59 return error("expected ':', got '%c'", *p
);
60 *mode1
= (int)strtol(p
+ 1, &p
, 8);
62 return error("expected ' ', got '%c'", *p
);
63 *mode2
= (int)strtol(p
+ 1, &p
, 8);
65 return error("expected ' ', got '%c'", *p
);
66 if (get_oid_hex(++p
, oid1
))
67 return error("expected object ID, got '%s'", p
+ 1);
70 return error("expected ' ', got '%c'", *p
);
71 if (get_oid_hex(++p
, oid2
))
72 return error("expected object ID, got '%s'", p
+ 1);
75 return error("expected ' ', got '%c'", *p
);
78 return error("missing status");
79 if (p
[1] && !isdigit(p
[1]))
80 return error("unexpected trailer: '%s'", p
+ 1);
85 * Remove any trailing slash from $workdir
86 * before starting to avoid double slashes in symlink targets.
88 static void add_path(struct strbuf
*buf
, size_t base_len
, const char *path
)
90 strbuf_setlen(buf
, base_len
);
91 if (buf
->len
&& buf
->buf
[buf
->len
- 1] != '/')
92 strbuf_addch(buf
, '/');
93 strbuf_addstr(buf
, path
);
97 * Determine whether we can simply reuse the file in the worktree.
99 static int use_wt_file(const char *workdir
, const char *name
,
100 struct object_id
*oid
)
102 struct strbuf buf
= STRBUF_INIT
;
106 strbuf_addstr(&buf
, workdir
);
107 add_path(&buf
, buf
.len
, name
);
109 if (!lstat(buf
.buf
, &st
) && !S_ISLNK(st
.st_mode
)) {
110 struct object_id wt_oid
;
111 int fd
= open(buf
.buf
, O_RDONLY
);
114 !index_fd(wt_oid
.hash
, fd
, &st
, OBJ_BLOB
, name
, 0)) {
115 if (is_null_oid(oid
)) {
116 oidcpy(oid
, &wt_oid
);
118 } else if (!oidcmp(oid
, &wt_oid
))
123 strbuf_release(&buf
);
128 struct working_tree_entry
{
129 struct hashmap_entry entry
;
130 char path
[FLEX_ARRAY
];
133 static int working_tree_entry_cmp(struct working_tree_entry
*a
,
134 struct working_tree_entry
*b
, void *keydata
)
136 return strcmp(a
->path
, b
->path
);
140 * The `left` and `right` entries hold paths for the symlinks hashmap,
141 * and a SHA-1 surrounded by brief text for submodules.
144 struct hashmap_entry entry
;
145 char left
[PATH_MAX
], right
[PATH_MAX
];
146 const char path
[FLEX_ARRAY
];
149 static int pair_cmp(struct pair_entry
*a
, struct pair_entry
*b
, void *keydata
)
151 return strcmp(a
->path
, b
->path
);
154 static void add_left_or_right(struct hashmap
*map
, const char *path
,
155 const char *content
, int is_right
)
157 struct pair_entry
*e
, *existing
;
159 FLEX_ALLOC_STR(e
, path
, path
);
160 hashmap_entry_init(e
, strhash(path
));
161 existing
= hashmap_get(map
, e
, NULL
);
166 e
->left
[0] = e
->right
[0] = '\0';
169 strlcpy(is_right
? e
->right
: e
->left
, content
, PATH_MAX
);
173 struct hashmap_entry entry
;
174 char path
[FLEX_ARRAY
];
177 static int path_entry_cmp(struct path_entry
*a
, struct path_entry
*b
, void *key
)
179 return strcmp(a
->path
, key
? key
: b
->path
);
182 static void changed_files(struct hashmap
*result
, const char *index_path
,
185 struct child_process update_index
= CHILD_PROCESS_INIT
;
186 struct child_process diff_files
= CHILD_PROCESS_INIT
;
187 struct strbuf index_env
= STRBUF_INIT
, buf
= STRBUF_INIT
;
188 const char *git_dir
= absolute_path(get_git_dir()), *env
[] = {
193 strbuf_addf(&index_env
, "GIT_INDEX_FILE=%s", index_path
);
194 env
[0] = index_env
.buf
;
196 argv_array_pushl(&update_index
.args
,
197 "--git-dir", git_dir
, "--work-tree", workdir
,
198 "update-index", "--really-refresh", "-q",
200 update_index
.no_stdin
= 1;
201 update_index
.no_stdout
= 1;
202 update_index
.no_stderr
= 1;
203 update_index
.git_cmd
= 1;
204 update_index
.use_shell
= 0;
205 update_index
.clean_on_exit
= 1;
206 update_index
.dir
= workdir
;
207 update_index
.env
= env
;
208 /* Ignore any errors of update-index */
209 run_command(&update_index
);
211 argv_array_pushl(&diff_files
.args
,
212 "--git-dir", git_dir
, "--work-tree", workdir
,
213 "diff-files", "--name-only", "-z", NULL
);
214 diff_files
.no_stdin
= 1;
215 diff_files
.git_cmd
= 1;
216 diff_files
.use_shell
= 0;
217 diff_files
.clean_on_exit
= 1;
219 diff_files
.dir
= workdir
;
220 diff_files
.env
= env
;
221 if (start_command(&diff_files
))
222 die("could not obtain raw diff");
223 fp
= xfdopen(diff_files
.out
, "r");
224 while (!strbuf_getline_nul(&buf
, fp
)) {
225 struct path_entry
*entry
;
226 FLEX_ALLOC_STR(entry
, path
, buf
.buf
);
227 hashmap_entry_init(entry
, strhash(buf
.buf
));
228 hashmap_add(result
, entry
);
231 if (finish_command(&diff_files
))
232 die("diff-files did not exit properly");
233 strbuf_release(&index_env
);
234 strbuf_release(&buf
);
237 static NORETURN
void exit_cleanup(const char *tmpdir
, int exit_code
)
239 struct strbuf buf
= STRBUF_INIT
;
240 strbuf_addstr(&buf
, tmpdir
);
241 remove_dir_recursively(&buf
, 0);
243 warning(_("failed: %d"), exit_code
);
247 static int ensure_leading_directories(char *path
)
249 switch (safe_create_leading_directories(path
)) {
254 return error(_("could not create leading directories "
260 * Unconditional writing of a plain regular file is what
261 * "git difftool --dir-diff" wants to do for symlinks. We are preparing two
262 * temporary directories to be fed to a Git-unaware tool that knows how to
263 * show a diff of two directories (e.g. "diff -r A B").
265 * Because the tool is Git-unaware, if a symbolic link appears in either of
266 * these temporary directories, it will try to dereference and show the
267 * difference of the target of the symbolic link, which is not what we want,
268 * as the goal of the dir-diff mode is to produce an output that is logically
269 * equivalent to what "git diff" produces.
271 * Most importantly, we want to get textual comparison of the result of the
272 * readlink(2). get_symlink() provides that---it returns the contents of
273 * the symlink that gets written to a regular file to force the external tool
274 * to compare the readlink(2) result as text, even on a filesystem that is
275 * capable of doing a symbolic link.
277 static char *get_symlink(const struct object_id
*oid
, const char *path
)
280 if (is_null_oid(oid
)) {
281 /* The symlink is unknown to Git so read from the filesystem */
282 struct strbuf link
= STRBUF_INIT
;
284 if (strbuf_readlink(&link
, path
, strlen(path
)))
285 die(_("could not read symlink %s"), path
);
286 } else if (strbuf_read_file(&link
, path
, 128))
287 die(_("could not read symlink file %s"), path
);
289 data
= strbuf_detach(&link
, NULL
);
291 enum object_type type
;
293 data
= read_sha1_file(oid
->hash
, &type
, &size
);
295 die(_("could not read object %s for symlink %s"),
296 oid_to_hex(oid
), path
);
302 static int checkout_path(unsigned mode
, struct object_id
*oid
,
303 const char *path
, const struct checkout
*state
)
305 struct cache_entry
*ce
;
308 ce
= make_cache_entry(mode
, oid
->hash
, path
, 0, 0);
309 ret
= checkout_entry(ce
, state
, NULL
);
315 static int run_dir_diff(const char *extcmd
, int symlinks
, const char *prefix
,
316 int argc
, const char **argv
)
318 char tmpdir
[PATH_MAX
];
319 struct strbuf info
= STRBUF_INIT
, lpath
= STRBUF_INIT
;
320 struct strbuf rpath
= STRBUF_INIT
, buf
= STRBUF_INIT
;
321 struct strbuf ldir
= STRBUF_INIT
, rdir
= STRBUF_INIT
;
322 struct strbuf wtdir
= STRBUF_INIT
;
323 char *lbase_dir
, *rbase_dir
;
324 size_t ldir_len
, rdir_len
, wtdir_len
;
325 const char *workdir
, *tmp
;
328 struct hashmap working_tree_dups
, submodules
, symlinks2
;
329 struct hashmap_iter iter
;
330 struct pair_entry
*entry
;
331 struct index_state wtindex
;
332 struct checkout lstate
, rstate
;
333 int rc
, flags
= RUN_GIT_CMD
, err
= 0;
334 struct child_process child
= CHILD_PROCESS_INIT
;
335 const char *helper_argv
[] = { "difftool--helper", NULL
, NULL
, NULL
};
336 struct hashmap wt_modified
, tmp_modified
;
337 int indices_loaded
= 0;
339 workdir
= get_git_work_tree();
341 /* Setup temp directories */
342 tmp
= getenv("TMPDIR");
343 xsnprintf(tmpdir
, sizeof(tmpdir
), "%s/git-difftool.XXXXXX", tmp
? tmp
: "/tmp");
344 if (!mkdtemp(tmpdir
))
345 return error("could not create '%s'", tmpdir
);
346 strbuf_addf(&ldir
, "%s/left/", tmpdir
);
347 strbuf_addf(&rdir
, "%s/right/", tmpdir
);
348 strbuf_addstr(&wtdir
, workdir
);
349 if (!wtdir
.len
|| !is_dir_sep(wtdir
.buf
[wtdir
.len
- 1]))
350 strbuf_addch(&wtdir
, '/');
351 mkdir(ldir
.buf
, 0700);
352 mkdir(rdir
.buf
, 0700);
354 memset(&wtindex
, 0, sizeof(wtindex
));
356 memset(&lstate
, 0, sizeof(lstate
));
357 lstate
.base_dir
= lbase_dir
= xstrdup(ldir
.buf
);
358 lstate
.base_dir_len
= ldir
.len
;
360 memset(&rstate
, 0, sizeof(rstate
));
361 rstate
.base_dir
= rbase_dir
= xstrdup(rdir
.buf
);
362 rstate
.base_dir_len
= rdir
.len
;
367 wtdir_len
= wtdir
.len
;
369 hashmap_init(&working_tree_dups
,
370 (hashmap_cmp_fn
)working_tree_entry_cmp
, 0);
371 hashmap_init(&submodules
, (hashmap_cmp_fn
)pair_cmp
, 0);
372 hashmap_init(&symlinks2
, (hashmap_cmp_fn
)pair_cmp
, 0);
377 child
.clean_on_exit
= 1;
380 argv_array_pushl(&child
.args
, "diff", "--raw", "--no-abbrev", "-z",
382 for (i
= 0; i
< argc
; i
++)
383 argv_array_push(&child
.args
, argv
[i
]);
384 if (start_command(&child
))
385 die("could not obtain raw diff");
386 fp
= xfdopen(child
.out
, "r");
388 /* Build index info for left and right sides of the diff */
390 while (!strbuf_getline_nul(&info
, fp
)) {
392 struct object_id loid
, roid
;
394 const char *src_path
, *dst_path
;
396 if (starts_with(info
.buf
, "::"))
397 die(N_("combined diff formats('-c' and '--cc') are "
399 "directory diff mode('-d' and '--dir-diff')."));
401 if (parse_index_info(info
.buf
, &lmode
, &rmode
, &loid
, &roid
,
404 if (strbuf_getline_nul(&lpath
, fp
))
406 src_path
= lpath
.buf
;
409 if (status
!= 'C' && status
!= 'R') {
412 if (strbuf_getline_nul(&rpath
, fp
))
414 dst_path
= rpath
.buf
;
417 if (S_ISGITLINK(lmode
) || S_ISGITLINK(rmode
)) {
419 strbuf_addf(&buf
, "Subproject commit %s",
421 add_left_or_right(&submodules
, src_path
, buf
.buf
, 0);
423 strbuf_addf(&buf
, "Subproject commit %s",
425 if (!oidcmp(&loid
, &roid
))
426 strbuf_addstr(&buf
, "-dirty");
427 add_left_or_right(&submodules
, dst_path
, buf
.buf
, 1);
431 if (S_ISLNK(lmode
)) {
432 char *content
= get_symlink(&loid
, src_path
);
433 add_left_or_right(&symlinks2
, src_path
, content
, 0);
437 if (S_ISLNK(rmode
)) {
438 char *content
= get_symlink(&roid
, dst_path
);
439 add_left_or_right(&symlinks2
, dst_path
, content
, 1);
443 if (lmode
&& status
!= 'C') {
444 if (checkout_path(lmode
, &loid
, src_path
, &lstate
)) {
445 ret
= error("could not write '%s'", src_path
);
450 if (rmode
&& !S_ISLNK(rmode
)) {
451 struct working_tree_entry
*entry
;
453 /* Avoid duplicate working_tree entries */
454 FLEX_ALLOC_STR(entry
, path
, dst_path
);
455 hashmap_entry_init(entry
, strhash(dst_path
));
456 if (hashmap_get(&working_tree_dups
, entry
, NULL
)) {
460 hashmap_add(&working_tree_dups
, entry
);
462 if (!use_wt_file(workdir
, dst_path
, &roid
)) {
463 if (checkout_path(rmode
, &roid
, dst_path
,
465 ret
= error("could not write '%s'",
469 } else if (!is_null_oid(&roid
)) {
471 * Changes in the working tree need special
472 * treatment since they are not part of the
475 struct cache_entry
*ce2
=
476 make_cache_entry(rmode
, roid
.hash
,
479 add_index_entry(&wtindex
, ce2
,
480 ADD_CACHE_JUST_APPEND
);
482 add_path(&rdir
, rdir_len
, dst_path
);
483 if (ensure_leading_directories(rdir
.buf
)) {
484 ret
= error("could not create "
485 "directory for '%s'",
489 add_path(&wtdir
, wtdir_len
, dst_path
);
491 if (symlink(wtdir
.buf
, rdir
.buf
)) {
492 ret
= error_errno("could not symlink '%s' to '%s'", wtdir
.buf
, rdir
.buf
);
497 if (stat(wtdir
.buf
, &st
))
499 if (copy_file(rdir
.buf
, wtdir
.buf
,
501 ret
= error("could not copy '%s' to '%s'", wtdir
.buf
, rdir
.buf
);
511 if (finish_command(&child
)) {
512 ret
= error("error occurred running diff --raw");
520 * Changes to submodules require special treatment.This loop writes a
521 * temporary file to both the left and right directories to show the
522 * change in the recorded SHA1 for the submodule.
524 hashmap_iter_init(&submodules
, &iter
);
525 while ((entry
= hashmap_iter_next(&iter
))) {
527 add_path(&ldir
, ldir_len
, entry
->path
);
528 ensure_leading_directories(ldir
.buf
);
529 write_file(ldir
.buf
, "%s", entry
->left
);
532 add_path(&rdir
, rdir_len
, entry
->path
);
533 ensure_leading_directories(rdir
.buf
);
534 write_file(rdir
.buf
, "%s", entry
->right
);
539 * Symbolic links require special treatment.The standard "git diff"
540 * shows only the link itself, not the contents of the link target.
541 * This loop replicates that behavior.
543 hashmap_iter_init(&symlinks2
, &iter
);
544 while ((entry
= hashmap_iter_next(&iter
))) {
546 add_path(&ldir
, ldir_len
, entry
->path
);
547 ensure_leading_directories(ldir
.buf
);
548 write_file(ldir
.buf
, "%s", entry
->left
);
551 add_path(&rdir
, rdir_len
, entry
->path
);
552 ensure_leading_directories(rdir
.buf
);
553 write_file(rdir
.buf
, "%s", entry
->right
);
557 strbuf_release(&buf
);
559 strbuf_setlen(&ldir
, ldir_len
);
560 helper_argv
[1] = ldir
.buf
;
561 strbuf_setlen(&rdir
, rdir_len
);
562 helper_argv
[2] = rdir
.buf
;
565 helper_argv
[0] = extcmd
;
568 setenv("GIT_DIFFTOOL_DIRDIFF", "true", 1);
569 rc
= run_command_v_opt(helper_argv
, flags
);
572 * If the diff includes working copy files and those
573 * files were modified during the diff, then the changes
574 * should be copied back to the working tree.
575 * Do not copy back files when symlinks are used and the
576 * external tool did not replace the original link with a file.
578 * These hashes are loaded lazily since they aren't needed
579 * in the common case of --symlinks and the difftool updating
580 * files through the symlink.
582 hashmap_init(&wt_modified
, (hashmap_cmp_fn
)path_entry_cmp
,
584 hashmap_init(&tmp_modified
, (hashmap_cmp_fn
)path_entry_cmp
,
587 for (i
= 0; i
< wtindex
.cache_nr
; i
++) {
588 struct hashmap_entry dummy
;
589 const char *name
= wtindex
.cache
[i
]->name
;
592 add_path(&rdir
, rdir_len
, name
);
593 if (lstat(rdir
.buf
, &st
))
596 if ((symlinks
&& S_ISLNK(st
.st_mode
)) || !S_ISREG(st
.st_mode
))
599 if (!indices_loaded
) {
600 static struct lock_file lock
;
602 strbuf_addf(&buf
, "%s/wtindex", tmpdir
);
603 if (hold_lock_file_for_update(&lock
, buf
.buf
, 0) < 0 ||
604 write_locked_index(&wtindex
, &lock
, COMMIT_LOCK
)) {
605 ret
= error("could not write %s", buf
.buf
);
606 rollback_lock_file(&lock
);
609 changed_files(&wt_modified
, buf
.buf
, workdir
);
610 strbuf_setlen(&rdir
, rdir_len
);
611 changed_files(&tmp_modified
, buf
.buf
, rdir
.buf
);
612 add_path(&rdir
, rdir_len
, name
);
616 hashmap_entry_init(&dummy
, strhash(name
));
617 if (hashmap_get(&tmp_modified
, &dummy
, name
)) {
618 add_path(&wtdir
, wtdir_len
, name
);
619 if (hashmap_get(&wt_modified
, &dummy
, name
)) {
620 warning(_("both files modified: '%s' and '%s'."),
621 wtdir
.buf
, rdir
.buf
);
622 warning(_("working tree file has been left."));
625 } else if (unlink(wtdir
.buf
) ||
626 copy_file(wtdir
.buf
, rdir
.buf
, st
.st_mode
))
627 warning_errno(_("could not copy '%s' to '%s'"),
628 rdir
.buf
, wtdir
.buf
);
633 warning(_("temporary files exist in '%s'."), tmpdir
);
634 warning(_("you may want to cleanup or recover these."));
637 exit_cleanup(tmpdir
, rc
);
645 strbuf_release(&ldir
);
646 strbuf_release(&rdir
);
647 strbuf_release(&wtdir
);
648 strbuf_release(&buf
);
653 static int run_file_diff(int prompt
, const char *prefix
,
654 int argc
, const char **argv
)
656 struct argv_array args
= ARGV_ARRAY_INIT
;
657 const char *env
[] = {
658 "GIT_PAGER=", "GIT_EXTERNAL_DIFF=git-difftool--helper", NULL
,
664 env
[2] = "GIT_DIFFTOOL_PROMPT=true";
666 env
[2] = "GIT_DIFFTOOL_NO_PROMPT=true";
669 argv_array_push(&args
, "diff");
670 for (i
= 0; i
< argc
; i
++)
671 argv_array_push(&args
, argv
[i
]);
672 ret
= run_command_v_opt_cd_env(args
.argv
, RUN_GIT_CMD
, prefix
, env
);
676 int cmd_difftool(int argc
, const char **argv
, const char *prefix
)
678 int use_gui_tool
= 0, dir_diff
= 0, prompt
= -1, symlinks
= 0,
680 static char *difftool_cmd
= NULL
, *extcmd
= NULL
;
681 struct option builtin_difftool_options
[] = {
682 OPT_BOOL('g', "gui", &use_gui_tool
,
683 N_("use `diff.guitool` instead of `diff.tool`")),
684 OPT_BOOL('d', "dir-diff", &dir_diff
,
685 N_("perform a full-directory diff")),
686 { OPTION_SET_INT
, 'y', "no-prompt", &prompt
, NULL
,
687 N_("do not prompt before launching a diff tool"),
688 PARSE_OPT_NOARG
| PARSE_OPT_NONEG
, NULL
, 0},
689 { OPTION_SET_INT
, 0, "prompt", &prompt
, NULL
, NULL
,
690 PARSE_OPT_NOARG
| PARSE_OPT_NONEG
| PARSE_OPT_HIDDEN
,
692 OPT_BOOL(0, "symlinks", &symlinks
,
693 N_("use symlinks in dir-diff mode")),
694 OPT_STRING('t', "tool", &difftool_cmd
, N_("<tool>"),
695 N_("use the specified diff tool")),
696 OPT_BOOL(0, "tool-help", &tool_help
,
697 N_("print a list of diff tools that may be used with "
699 OPT_BOOL(0, "trust-exit-code", &trust_exit_code
,
700 N_("make 'git-difftool' exit when an invoked diff "
701 "tool returns a non - zero exit code")),
702 OPT_STRING('x', "extcmd", &extcmd
, N_("<command>"),
703 N_("specify a custom command for viewing diffs")),
707 git_config(difftool_config
, NULL
);
708 symlinks
= has_symlinks
;
710 argc
= parse_options(argc
, argv
, prefix
, builtin_difftool_options
,
711 builtin_difftool_usage
, PARSE_OPT_KEEP_UNKNOWN
|
712 PARSE_OPT_KEEP_DASHDASH
);
715 return print_tool_help();
717 /* NEEDSWORK: once we no longer spawn anything, remove this */
718 setenv(GIT_DIR_ENVIRONMENT
, absolute_path(get_git_dir()), 1);
719 setenv(GIT_WORK_TREE_ENVIRONMENT
, absolute_path(get_git_work_tree()), 1);
721 if (use_gui_tool
&& diff_gui_tool
&& *diff_gui_tool
)
722 setenv("GIT_DIFF_TOOL", diff_gui_tool
, 1);
723 else if (difftool_cmd
) {
725 setenv("GIT_DIFF_TOOL", difftool_cmd
, 1);
727 die(_("no <tool> given for --tool=<tool>"));
732 setenv("GIT_DIFFTOOL_EXTCMD", extcmd
, 1);
734 die(_("no <cmd> given for --extcmd=<cmd>"));
737 setenv("GIT_DIFFTOOL_TRUST_EXIT_CODE",
738 trust_exit_code
? "true" : "false", 1);
741 * In directory diff mode, 'git-difftool--helper' is called once
742 * to compare the a / b directories. In file diff mode, 'git diff'
743 * will invoke a separate instance of 'git-difftool--helper' for
744 * each file that changed.
747 return run_dir_diff(extcmd
, symlinks
, prefix
, argc
, argv
);
748 return run_file_diff(prompt
, prefix
, argc
, argv
);