2 * Copyright (C) 2005 Junio C Hamano
11 static const char *diff_opts
= "-pu";
12 static unsigned char null_sha1
[20] = { 0, };
14 static int reverse_diff
;
15 static int generate_patch
;
16 static int line_termination
= '\n';
17 static int inter_name_termination
= '\t';
19 static const char *external_diff(void)
21 static const char *external_diff_cmd
= NULL
;
22 static int done_preparing
= 0;
25 return external_diff_cmd
;
28 * Default values above are meant to match the
29 * Linux kernel development style. Examples of
30 * alternative styles you can specify via environment
35 if (gitenv("GIT_EXTERNAL_DIFF"))
36 external_diff_cmd
= gitenv("GIT_EXTERNAL_DIFF");
38 /* In case external diff fails... */
39 diff_opts
= gitenv("GIT_DIFF_OPTS") ? : diff_opts
;
42 return external_diff_cmd
;
45 /* Help to copy the thing properly quoted for the shell safety.
46 * any single quote is replaced with '\'', and the caller is
47 * expected to enclose the result within a single quote pair.
50 * original sq_expand result
51 * name ==> name ==> 'name'
52 * a b ==> a b ==> 'a b'
53 * a'b ==> a'\''b ==> 'a'\''b'
55 static char *sq_expand(const char *src
)
57 static char *buf
= NULL
;
62 /* count bytes needed to store the quoted string. */
63 for (cnt
= 1, cp
= src
; *cp
; cnt
++, cp
++)
69 while ((c
= *src
++)) {
73 bp
= strcpy(bp
, "'\\''");
81 static struct diff_tempfile
{
82 const char *name
; /* filename external diff should read from */
88 static void builtin_diff(const char *name_a
,
90 struct diff_tempfile
*temp
,
93 int i
, next_at
, cmd_size
;
94 const char *diff_cmd
= "diff -L'%s%s' -L'%s%s'";
95 const char *diff_arg
= "'%s' '%s'||:"; /* "||:" is to return 0 */
96 const char *input_name_sq
[2];
99 const char *name_sq
[2];
102 name_sq
[0] = sq_expand(name_a
);
103 name_sq
[1] = sq_expand(name_b
);
105 /* diff_cmd and diff_arg have 6 %s in total which makes
106 * the sum of these strings 12 bytes larger than required.
107 * we use 2 spaces around diff-opts, and we need to count
108 * terminating NUL, so we subtract 9 here.
110 cmd_size
= (strlen(diff_cmd
) + strlen(diff_opts
) +
111 strlen(diff_arg
) - 9);
112 for (i
= 0; i
< 2; i
++) {
113 input_name_sq
[i
] = sq_expand(temp
[i
].name
);
114 if (!strcmp(temp
[i
].name
, "/dev/null")) {
115 path0
[i
] = "/dev/null";
118 path0
[i
] = i
? "b/" : "a/";
119 path1
[i
] = name_sq
[i
];
121 cmd_size
+= (strlen(path0
[i
]) + strlen(path1
[i
]) +
122 strlen(input_name_sq
[i
]));
125 cmd
= xmalloc(cmd_size
);
128 next_at
+= snprintf(cmd
+next_at
, cmd_size
-next_at
,
130 path0
[0], path1
[0], path0
[1], path1
[1]);
131 next_at
+= snprintf(cmd
+next_at
, cmd_size
-next_at
,
133 next_at
+= snprintf(cmd
+next_at
, cmd_size
-next_at
,
134 diff_arg
, input_name_sq
[0], input_name_sq
[1]);
136 printf("diff --git a/%s b/%s\n", name_a
, name_b
);
138 printf("new file mode %s\n", temp
[1].mode
);
139 else if (!path1
[1][0])
140 printf("deleted file mode %s\n", temp
[0].mode
);
142 if (strcmp(temp
[0].mode
, temp
[1].mode
)) {
143 printf("old mode %s\n", temp
[0].mode
);
144 printf("new mode %s\n", temp
[1].mode
);
146 if (xfrm_msg
&& xfrm_msg
[0])
147 fputs(xfrm_msg
, stdout
);
149 if (strncmp(temp
[0].mode
, temp
[1].mode
, 3))
150 /* we do not run diff between different kind
156 execlp("/bin/sh","sh", "-c", cmd
, NULL
);
159 struct diff_filespec
*alloc_filespec(const char *path
)
161 int namelen
= strlen(path
);
162 struct diff_filespec
*spec
= xmalloc(sizeof(*spec
) + namelen
+ 1);
163 spec
->path
= (char *)(spec
+ 1);
164 strcpy(spec
->path
, path
);
165 spec
->should_free
= spec
->should_munmap
= 0;
166 spec
->xfrm_flags
= 0;
170 memset(spec
->sha1
, 0, 20);
174 void fill_filespec(struct diff_filespec
*spec
, const unsigned char *sha1
,
177 if (mode
) { /* just playing defensive */
179 memcpy(spec
->sha1
, sha1
, 20);
180 spec
->sha1_valid
= !!memcmp(sha1
, null_sha1
, 20);
185 * Given a name and sha1 pair, if the dircache tells us the file in
186 * the work tree has that object contents, return true, so that
187 * prepare_temp_file() does not have to inflate and extract.
189 static int work_tree_matches(const char *name
, const unsigned char *sha1
)
191 struct cache_entry
*ce
;
195 /* We do not read the cache ourselves here, because the
196 * benchmark with my previous version that always reads cache
197 * shows that it makes things worse for diff-tree comparing
198 * two linux-2.6 kernel trees in an already checked out work
199 * tree. This is because most diff-tree comparisons deal with
200 * only a small number of files, while reading the cache is
201 * expensive for a large project, and its cost outweighs the
202 * savings we get by not inflating the object to a temporary
203 * file. Practically, this code only helps when we are used
204 * by diff-cache --cached, which does read the cache before
211 pos
= cache_name_pos(name
, len
);
214 ce
= active_cache
[pos
];
215 if ((lstat(name
, &st
) < 0) ||
216 !S_ISREG(st
.st_mode
) || /* careful! */
217 ce_match_stat(ce
, &st
) ||
218 memcmp(sha1
, ce
->sha1
, 20))
220 /* we return 1 only when we can stat, it is a regular file,
221 * stat information matches, and sha1 recorded in the cache
222 * matches. I.e. we know the file in the work tree really is
223 * the same as the <name, sha1> pair.
229 * While doing rename detection and pickaxe operation, we may need to
230 * grab the data for the blob (or file) for our own in-core comparison.
231 * diff_filespec has data and size fields for this purpose.
233 int diff_populate_filespec(struct diff_filespec
*s
)
236 if (!DIFF_FILE_VALID(s
))
237 die("internal error: asking to populate invalid file.");
238 if (S_ISDIR(s
->mode
))
243 if (!s
->sha1_valid
||
244 work_tree_matches(s
->path
, s
->sha1
)) {
247 if (lstat(s
->path
, &st
) < 0) {
248 if (errno
== ENOENT
) {
257 s
->size
= st
.st_size
;
260 if (S_ISLNK(st
.st_mode
)) {
262 s
->data
= xmalloc(s
->size
);
264 ret
= readlink(s
->path
, s
->data
, s
->size
);
271 fd
= open(s
->path
, O_RDONLY
);
274 s
->data
= mmap(NULL
, s
->size
, PROT_READ
, MAP_PRIVATE
, fd
, 0);
275 s
->should_munmap
= 1;
280 s
->data
= read_sha1_file(s
->sha1
, type
, &s
->size
);
286 void diff_free_filepair(struct diff_filepair
*p
)
292 void diff_free_filespec_data(struct diff_filespec
*s
)
296 else if (s
->should_munmap
)
297 munmap(s
->data
, s
->size
);
298 s
->should_free
= s
->should_munmap
= 0;
302 static void prep_temp_blob(struct diff_tempfile
*temp
,
310 strcpy(temp
->tmp_path
, ".diff_XXXXXX");
311 fd
= mkstemp(temp
->tmp_path
);
313 die("unable to create temp-file");
314 if (write(fd
, blob
, size
) != size
)
315 die("unable to write temp-file");
317 temp
->name
= temp
->tmp_path
;
318 strcpy(temp
->hex
, sha1_to_hex(sha1
));
320 sprintf(temp
->mode
, "%06o", mode
);
323 static void prepare_temp_file(const char *name
,
324 struct diff_tempfile
*temp
,
325 struct diff_filespec
*one
)
327 if (!DIFF_FILE_VALID(one
)) {
329 /* A '-' entry produces this for file-2, and
330 * a '+' entry produces this for file-1.
332 temp
->name
= "/dev/null";
333 strcpy(temp
->hex
, ".");
334 strcpy(temp
->mode
, ".");
338 if (!one
->sha1_valid
||
339 work_tree_matches(name
, one
->sha1
)) {
341 if (lstat(name
, &st
) < 0) {
343 goto not_a_valid_file
;
344 die("stat(%s): %s", name
, strerror(errno
));
346 if (S_ISLNK(st
.st_mode
)) {
348 char *buf
, buf_
[1024];
349 buf
= ((sizeof(buf_
) < st
.st_size
) ?
350 xmalloc(st
.st_size
) : buf_
);
351 ret
= readlink(name
, buf
, st
.st_size
);
353 die("readlink(%s)", name
);
354 prep_temp_blob(temp
, buf
, st
.st_size
,
356 one
->sha1
: null_sha1
),
358 one
->mode
: S_IFLNK
));
361 /* we can borrow from the file in the work tree */
363 if (!one
->sha1_valid
)
364 strcpy(temp
->hex
, sha1_to_hex(null_sha1
));
366 strcpy(temp
->hex
, sha1_to_hex(one
->sha1
));
367 sprintf(temp
->mode
, "%06o",
368 S_IFREG
|ce_permissions(st
.st_mode
));
373 if (diff_populate_filespec(one
))
374 die("cannot read data blob for %s", one
->path
);
375 prep_temp_blob(temp
, one
->data
, one
->size
,
376 one
->sha1
, one
->mode
);
380 static void remove_tempfile(void)
384 for (i
= 0; i
< 2; i
++)
385 if (diff_temp
[i
].name
== diff_temp
[i
].tmp_path
) {
386 unlink(diff_temp
[i
].name
);
387 diff_temp
[i
].name
= NULL
;
391 static void remove_tempfile_on_signal(int signo
)
396 /* An external diff command takes:
398 * diff-cmd name infile1 infile1-sha1 infile1-mode \
399 * infile2 infile2-sha1 infile2-mode [ rename-to ]
402 static void run_external_diff(const char *name
,
404 struct diff_filespec
*one
,
405 struct diff_filespec
*two
,
406 const char *xfrm_msg
)
408 struct diff_tempfile
*temp
= diff_temp
;
411 static int atexit_asked
= 0;
414 prepare_temp_file(name
, &temp
[0], one
);
415 prepare_temp_file(other
? : name
, &temp
[1], two
);
416 if (! atexit_asked
&&
417 (temp
[0].name
== temp
[0].tmp_path
||
418 temp
[1].name
== temp
[1].tmp_path
)) {
420 atexit(remove_tempfile
);
422 signal(SIGINT
, remove_tempfile_on_signal
);
428 die("unable to fork");
430 const char *pgm
= external_diff();
433 const char *exec_arg
[10];
434 const char **arg
= &exec_arg
[0];
437 *arg
++ = temp
[0].name
;
438 *arg
++ = temp
[0].hex
;
439 *arg
++ = temp
[0].mode
;
440 *arg
++ = temp
[1].name
;
441 *arg
++ = temp
[1].hex
;
442 *arg
++ = temp
[1].mode
;
448 execvp(pgm
, (char *const*) exec_arg
);
451 execlp(pgm
, pgm
, name
, NULL
);
454 * otherwise we use the built-in one.
457 builtin_diff(name
, other
? : name
, temp
, xfrm_msg
);
459 printf("* Unmerged path %s\n", name
);
462 if (waitpid(pid
, &status
, 0) < 0 ||
463 !WIFEXITED(status
) || WEXITSTATUS(status
)) {
464 /* Earlier we did not check the exit status because
465 * diff exits non-zero if files are different, and
466 * we are not interested in knowing that. It was a
467 * mistake which made it harder to quit a diff-*
468 * session that uses the git-apply-patch-script as
469 * the GIT_EXTERNAL_DIFF. A custom GIT_EXTERNAL_DIFF
470 * should also exit non-zero only when it wants to
471 * abort the entire diff-* session.
474 fprintf(stderr
, "external diff died, stopping at %s.\n", name
);
480 void diff_setup(int reverse_diff_
)
482 reverse_diff
= reverse_diff_
;
485 struct diff_queue_struct diff_queued_diff
;
487 void diff_q(struct diff_queue_struct
*queue
, struct diff_filepair
*dp
)
489 if (queue
->alloc
<= queue
->nr
) {
490 queue
->alloc
= alloc_nr(queue
->alloc
);
491 queue
->queue
= xrealloc(queue
->queue
,
492 sizeof(dp
) * queue
->alloc
);
494 queue
->queue
[queue
->nr
++] = dp
;
497 struct diff_filepair
*diff_queue(struct diff_queue_struct
*queue
,
498 struct diff_filespec
*one
,
499 struct diff_filespec
*two
)
501 struct diff_filepair
*dp
= xmalloc(sizeof(*dp
));
505 dp
->orig_order
= queue
->nr
;
511 static void diff_flush_raw(struct diff_filepair
*p
)
513 if (DIFF_PAIR_UNMERGED(p
)) {
514 printf("U %s%c", p
->one
->path
, line_termination
);
517 printf(":%06o %06o %s ",
518 p
->one
->mode
, p
->two
->mode
, sha1_to_hex(p
->one
->sha1
));
519 printf("%s%c%s%c%s%c",
520 sha1_to_hex(p
->two
->sha1
), inter_name_termination
,
521 p
->one
->path
, inter_name_termination
,
522 p
->two
->path
, line_termination
);
525 static void diff_flush_patch(struct diff_filepair
*p
)
527 const char *name
, *other
;
530 other
= (strcmp(name
, p
->two
->path
) ? p
->two
->path
: NULL
);
531 if ((DIFF_FILE_VALID(p
->one
) && S_ISDIR(p
->one
->mode
)) ||
532 (DIFF_FILE_VALID(p
->two
) && S_ISDIR(p
->two
->mode
)))
533 return; /* no tree diffs in patch format */
535 if (DIFF_PAIR_UNMERGED(p
))
536 run_external_diff(name
, NULL
, NULL
, NULL
, NULL
);
538 run_external_diff(name
, other
, p
->one
, p
->two
, p
->xfrm_msg
);
541 static int uninteresting(struct diff_filepair
*p
)
543 /* This function is written stricter than necessary to support
544 * the currently implemented transformers, but the idea is to
545 * let transformers to produce diff_filepairs any way they want,
546 * and filter and clean them up here before producing the output.
548 struct diff_filespec
*one
, *two
;
550 if (DIFF_PAIR_UNMERGED(p
))
551 return 0; /* unmerged is interesting */
556 /* deletion, addition, mode change and renames are all interesting. */
557 if (DIFF_FILE_VALID(one
) != DIFF_FILE_VALID(two
) ||
558 (one
->mode
!= two
->mode
) ||
559 strcmp(one
->path
, two
->path
))
562 /* both are valid and point at the same path. that is, we are
563 * dealing with a change.
565 if (one
->sha1_valid
&& two
->sha1_valid
&&
566 !memcmp(one
->sha1
, two
->sha1
, sizeof(one
->sha1
)))
567 return 1; /* no change */
568 if (!one
->sha1_valid
&& !two
->sha1_valid
)
569 return 1; /* both look at the same file on the filesystem. */
573 void diffcore_prune(void)
576 * Although rename/copy detection wants to have "no-change"
577 * entries fed into them, the downstream do not need to see
578 * them. This function removes such entries.
580 * The applications that use rename/copy should:
582 * (1) feed change and "no-change" entries via diff_queue().
583 * (2) call diffcore_rename, and any other future diffcore_xxx
584 * that would benefit by still having "no-change" entries.
585 * (3) call diffcore_prune
586 * (4) call other diffcore_xxx that do not need to see
587 * "no-change" entries.
589 struct diff_queue_struct
*q
= &diff_queued_diff
;
590 struct diff_queue_struct outq
;
594 outq
.nr
= outq
.alloc
= 0;
596 for (i
= 0; i
< q
->nr
; i
++) {
597 struct diff_filepair
*p
= q
->queue
[i
];
598 if (!uninteresting(p
))
601 diff_free_filepair(p
);
608 static void diff_flush_one(struct diff_filepair
*p
)
610 if (uninteresting(p
))
618 int diff_queue_is_empty(void)
620 struct diff_queue_struct
*q
= &diff_queued_diff
;
623 for (i
= 0; i
< q
->nr
; i
++) {
624 struct diff_filepair
*p
= q
->queue
[i
];
625 if (!uninteresting(p
))
631 void diff_flush(int diff_output_style
)
633 struct diff_queue_struct
*q
= &diff_queued_diff
;
637 switch (diff_output_style
) {
638 case DIFF_FORMAT_HUMAN
:
639 line_termination
= '\n';
640 inter_name_termination
= '\t';
642 case DIFF_FORMAT_MACHINE
:
643 line_termination
= inter_name_termination
= 0;
645 case DIFF_FORMAT_PATCH
:
649 for (i
= 0; i
< q
->nr
; i
++)
650 diff_flush_one(q
->queue
[i
]);
651 for (i
= 0; i
< q
->nr
; i
++) {
652 struct diff_filepair
*p
= q
->queue
[i
];
653 diff_free_filespec_data(p
->one
);
654 diff_free_filespec_data(p
->two
);
660 q
->nr
= q
->alloc
= 0;
663 void diff_addremove(int addremove
, unsigned mode
,
664 const unsigned char *sha1
,
665 const char *base
, const char *path
)
667 char concatpath
[PATH_MAX
];
668 struct diff_filespec
*one
, *two
;
670 /* This may look odd, but it is a preparation for
671 * feeding "there are unchanged files which should
672 * not produce diffs, but when you are doing copy
673 * detection you would need them, so here they are"
674 * entries to the diff-core. They will be prefixed
675 * with something like '=' or '*' (I haven't decided
676 * which but should not make any difference).
677 * Feeding the same new and old to diff_change() should
678 * also have the same effect. diff_flush() should
679 * filter uninteresting ones out at the final output
683 addremove
= (addremove
== '+' ? '-' :
684 addremove
== '-' ? '+' : addremove
);
686 if (!path
) path
= "";
687 sprintf(concatpath
, "%s%s", base
, path
);
688 one
= alloc_filespec(concatpath
);
689 two
= alloc_filespec(concatpath
);
691 if (addremove
!= '+')
692 fill_filespec(one
, sha1
, mode
);
693 if (addremove
!= '-')
694 fill_filespec(two
, sha1
, mode
);
696 diff_queue(&diff_queued_diff
, one
, two
);
699 void diff_guif(unsigned old_mode
,
701 const unsigned char *old_sha1
,
702 const unsigned char *new_sha1
,
703 const char *old_path
,
704 const char *new_path
)
706 struct diff_filespec
*one
, *two
;
710 const unsigned char *tmp_c
;
711 tmp
= old_mode
; old_mode
= new_mode
; new_mode
= tmp
;
712 tmp_c
= old_sha1
; old_sha1
= new_sha1
; new_sha1
= tmp_c
;
714 one
= alloc_filespec(old_path
);
715 two
= alloc_filespec(new_path
);
717 fill_filespec(one
, old_sha1
, old_mode
);
719 fill_filespec(two
, new_sha1
, new_mode
);
720 diff_queue(&diff_queued_diff
, one
, two
);
723 void diff_change(unsigned old_mode
, unsigned new_mode
,
724 const unsigned char *old_sha1
,
725 const unsigned char *new_sha1
,
726 const char *base
, const char *path
)
728 char concatpath
[PATH_MAX
];
729 struct diff_filespec
*one
, *two
;
733 const unsigned char *tmp_c
;
734 tmp
= old_mode
; old_mode
= new_mode
; new_mode
= tmp
;
735 tmp_c
= old_sha1
; old_sha1
= new_sha1
; new_sha1
= tmp_c
;
737 if (!path
) path
= "";
738 sprintf(concatpath
, "%s%s", base
, path
);
739 one
= alloc_filespec(concatpath
);
740 two
= alloc_filespec(concatpath
);
741 fill_filespec(one
, old_sha1
, old_mode
);
742 fill_filespec(two
, new_sha1
, new_mode
);
744 diff_queue(&diff_queued_diff
, one
, two
);
747 void diff_unmerge(const char *path
)
749 struct diff_filespec
*one
, *two
;
750 one
= alloc_filespec(path
);
751 two
= alloc_filespec(path
);
752 diff_queue(&diff_queued_diff
, one
, two
);