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_filespec_data(struct diff_filespec *s)
290 else if (s->should_munmap)
291 munmap(s->data, s->size);
292 s->should_free = s->should_munmap = 0;
296 static void prep_temp_blob(struct diff_tempfile *temp,
304 strcpy(temp->tmp_path, ".diff_XXXXXX");
305 fd = mkstemp(temp->tmp_path);
307 die("unable to create temp-file");
308 if (write(fd, blob, size) != size)
309 die("unable to write temp-file");
311 temp->name = temp->tmp_path;
312 strcpy(temp->hex, sha1_to_hex(sha1));
314 sprintf(temp->mode, "%06o", mode);
317 static void prepare_temp_file(const char *name,
318 struct diff_tempfile *temp,
319 struct diff_filespec *one)
321 if (!DIFF_FILE_VALID(one)) {
323 /* A '-' entry produces this for file-2, and
324 * a '+' entry produces this for file-1.
326 temp->name = "/dev/null";
327 strcpy(temp->hex, ".");
328 strcpy(temp->mode, ".");
332 if (!one->sha1_valid ||
333 work_tree_matches(name, one->sha1)) {
335 if (lstat(name, &st) < 0) {
337 goto not_a_valid_file;
338 die("stat(%s): %s", name, strerror(errno));
340 if (S_ISLNK(st.st_mode)) {
342 char *buf, buf_[1024];
343 buf = ((sizeof(buf_) < st.st_size) ?
344 xmalloc(st.st_size) : buf_);
345 ret = readlink(name, buf, st.st_size);
347 die("readlink(%s)", name);
348 prep_temp_blob(temp, buf, st.st_size,
350 one->sha1 : null_sha1),
352 one->mode : S_IFLNK));
355 /* we can borrow from the file in the work tree */
357 if (!one->sha1_valid)
358 strcpy(temp->hex, sha1_to_hex(null_sha1));
360 strcpy(temp->hex, sha1_to_hex(one->sha1));
361 sprintf(temp->mode, "%06o",
362 S_IFREG |ce_permissions(st.st_mode));
367 if (diff_populate_filespec(one))
368 die("cannot read data blob for %s", one->path);
369 prep_temp_blob(temp, one->data, one->size,
370 one->sha1, one->mode);
374 static void remove_tempfile(void)
378 for (i = 0; i < 2; i++)
379 if (diff_temp[i].name == diff_temp[i].tmp_path) {
380 unlink(diff_temp[i].name);
381 diff_temp[i].name = NULL;
385 static void remove_tempfile_on_signal(int signo)
390 /* An external diff command takes:
392 * diff-cmd name infile1 infile1-sha1 infile1-mode \
393 * infile2 infile2-sha1 infile2-mode [ rename-to ]
396 static void run_external_diff(const char *name,
398 struct diff_filespec *one,
399 struct diff_filespec *two,
400 const char *xfrm_msg)
402 struct diff_tempfile *temp = diff_temp;
405 static int atexit_asked = 0;
408 prepare_temp_file(name, &temp[0], one);
409 prepare_temp_file(other ? : name, &temp[1], two);
410 if (! atexit_asked &&
411 (temp[0].name == temp[0].tmp_path ||
412 temp[1].name == temp[1].tmp_path)) {
414 atexit(remove_tempfile);
416 signal(SIGINT, remove_tempfile_on_signal);
422 die("unable to fork");
424 const char *pgm = external_diff();
427 const char *exec_arg[10];
428 const char **arg = &exec_arg[0];
431 *arg++ = temp[0].name;
432 *arg++ = temp[0].hex;
433 *arg++ = temp[0].mode;
434 *arg++ = temp[1].name;
435 *arg++ = temp[1].hex;
436 *arg++ = temp[1].mode;
442 execvp(pgm, (char *const*) exec_arg);
445 execlp(pgm, pgm, name, NULL);
448 * otherwise we use the built-in one.
451 builtin_diff(name, other ? : name, temp, xfrm_msg);
453 printf("* Unmerged path %s\n", name);
456 if (waitpid(pid, &status, 0) < 0 ||
457 !WIFEXITED(status) || WEXITSTATUS(status)) {
458 /* Earlier we did not check the exit status because
459 * diff exits non-zero if files are different, and
460 * we are not interested in knowing that. It was a
461 * mistake which made it harder to quit a diff-*
462 * session that uses the git-apply-patch-script as
463 * the GIT_EXTERNAL_DIFF. A custom GIT_EXTERNAL_DIFF
464 * should also exit non-zero only when it wants to
465 * abort the entire diff-* session.
468 fprintf(stderr, "external diff died, stopping at %s.\n", name);
474 void diff_setup(int reverse_diff_)
476 reverse_diff = reverse_diff_;
479 struct diff_queue_struct diff_queued_diff;
481 void diff_q(struct diff_queue_struct *queue, struct diff_filepair *dp)
483 if (queue->alloc <= queue->nr) {
484 queue->alloc = alloc_nr(queue->alloc);
485 queue->queue = xrealloc(queue->queue,
486 sizeof(dp) * queue->alloc);
488 queue->queue[queue->nr++] = dp;
491 struct diff_filepair *diff_queue(struct diff_queue_struct *queue,
492 struct diff_filespec *one,
493 struct diff_filespec *two)
495 struct diff_filepair *dp = xmalloc(sizeof(*dp));
499 dp->orig_order = queue->nr;
505 static void diff_flush_raw(struct diff_filepair *p)
512 sprintf(status, "%c%1d", p->status, p->score);
516 status[0] = p->status;
520 printf(":%06o %06o %s ",
521 p->one->mode, p->two->mode, sha1_to_hex(p->one->sha1));
523 sha1_to_hex(p->two->sha1),
525 inter_name_termination,
528 printf("%c%s", inter_name_termination, p->two->path);
529 putchar(line_termination);
532 int diff_unmodified_pair(struct diff_filepair *p)
534 /* This function is written stricter than necessary to support
535 * the currently implemented transformers, but the idea is to
536 * let transformers to produce diff_filepairs any way they want,
537 * and filter and clean them up here before producing the output.
539 struct diff_filespec *one, *two;
541 if (DIFF_PAIR_UNMERGED(p))
542 return 0; /* unmerged is interesting */
547 /* deletion, addition, mode change and renames are all interesting. */
548 if (DIFF_FILE_VALID(one) != DIFF_FILE_VALID(two) ||
549 (one->mode != two->mode) ||
550 strcmp(one->path, two->path))
553 /* both are valid and point at the same path. that is, we are
554 * dealing with a change.
556 if (one->sha1_valid && two->sha1_valid &&
557 !memcmp(one->sha1, two->sha1, sizeof(one->sha1)))
558 return 1; /* no change */
559 if (!one->sha1_valid && !two->sha1_valid)
560 return 1; /* both look at the same file on the filesystem. */
564 static void diff_flush_patch(struct diff_filepair *p)
566 const char *name, *other;
567 char msg_[PATH_MAX*2+200], *msg;
569 /* diffcore_prune() keeps "stay" entries for diff-raw
570 * copy/rename detection, but when we are generating
571 * patches we do not need them.
573 if (diff_unmodified_pair(p))
577 other = (strcmp(name, p->two->path) ? p->two->path : NULL);
578 if ((DIFF_FILE_VALID(p->one) && S_ISDIR(p->one->mode)) ||
579 (DIFF_FILE_VALID(p->two) && S_ISDIR(p->two->mode)))
580 return; /* no tree diffs in patch format */
585 "similarity index %d%%\n"
588 (int)(0.5 + p->score * 100/MAX_SCORE),
589 p->one->path, p->two->path);
594 "similarity index %d%%\n"
597 (int)(0.5 + p->score * 100/MAX_SCORE),
598 p->one->path, p->two->path);
605 if (DIFF_PAIR_UNMERGED(p))
606 run_external_diff(name, NULL, NULL, NULL, NULL);
608 run_external_diff(name, other, p->one, p->two, msg);
611 int diff_needs_to_stay(struct diff_queue_struct *q, int i,
612 struct diff_filespec *it)
614 /* If it will be used in later entry (either stay or used
615 * as the source of rename/copy), we need to copy, not rename.
618 struct diff_filepair *p = q->queue[i++];
619 if (!DIFF_FILE_VALID(p->two))
620 continue; /* removed is fine */
621 if (strcmp(p->one->path, it->path))
622 continue; /* not relevant */
624 /* p has its src set to *it and it is not a delete;
625 * it will be used for in-place change, rename/copy,
626 * or just stays there. We cannot rename it out.
633 static int diff_used_as_source(struct diff_queue_struct *q, int lim,
634 struct diff_filespec *it)
637 for (i = 0; i < lim; i++) {
638 struct diff_filepair *p = q->queue[i++];
639 if (!strcmp(p->one->path, it->path))
645 void diffcore_prune(void)
648 * Although rename/copy detection wants to have "no-change"
649 * entries fed into them, the downstream do not need to see
650 * them, unless we had rename/copy for the same path earlier.
651 * This function removes such entries.
653 * The applications that use rename/copy should:
655 * (1) feed change and "no-change" entries via diff_queue().
656 * (2) call diffcore_rename, and any other future diffcore_xxx
657 * that would benefit by still having "no-change" entries.
658 * (3) call diffcore_prune
659 * (4) call other diffcore_xxx that do not need to see
660 * "no-change" entries.
661 * (5) call diff_flush().
663 struct diff_queue_struct *q = &diff_queued_diff;
664 struct diff_queue_struct outq;
668 outq.nr = outq.alloc = 0;
670 for (i = 0; i < q->nr; i++) {
671 struct diff_filepair *p = q->queue[i];
672 if (!diff_unmodified_pair(p) ||
673 diff_used_as_source(q, i, p->one))
683 int diff_queue_is_empty(void)
685 struct diff_queue_struct *q = &diff_queued_diff;
689 void diff_flush(int diff_output_style, int resolve_rename_copy)
691 struct diff_queue_struct *q = &diff_queued_diff;
695 switch (diff_output_style) {
696 case DIFF_FORMAT_HUMAN:
697 line_termination = '\n';
698 inter_name_termination = '\t';
700 case DIFF_FORMAT_MACHINE:
701 line_termination = inter_name_termination = 0;
703 case DIFF_FORMAT_PATCH:
707 for (i = 0; i < q->nr; i++) {
708 struct diff_filepair *p = q->queue[i];
709 if (resolve_rename_copy) {
710 if (DIFF_PAIR_UNMERGED(p))
712 else if (!DIFF_FILE_VALID((p)->one))
714 else if (!DIFF_FILE_VALID((p)->two))
716 else if (strcmp(p->one->path, p->two->path)) {
717 /* This is rename or copy. Which one is it? */
718 if (diff_needs_to_stay(q, i+1, p->one))
732 for (i = 0; i < q->nr; i++) {
733 struct diff_filepair *p = q->queue[i];
734 diff_free_filespec_data(p->one);
735 diff_free_filespec_data(p->two);
740 q->nr = q->alloc = 0;
743 void diff_addremove(int addremove, unsigned mode,
744 const unsigned char *sha1,
745 const char *base, const char *path)
747 char concatpath[PATH_MAX];
748 struct diff_filespec *one, *two;
750 /* This may look odd, but it is a preparation for
751 * feeding "there are unchanged files which should
752 * not produce diffs, but when you are doing copy
753 * detection you would need them, so here they are"
754 * entries to the diff-core. They will be prefixed
755 * with something like '=' or '*' (I haven't decided
756 * which but should not make any difference).
757 * Feeding the same new and old to diff_change()
758 * also has the same effect. diffcore_prune() should
759 * be used to filter uninteresting ones out before the
760 * final output happens.
763 addremove = (addremove == '+' ? '-' :
764 addremove == '-' ? '+' : addremove);
766 if (!path) path = "";
767 sprintf(concatpath, "%s%s", base, path);
768 one = alloc_filespec(concatpath);
769 two = alloc_filespec(concatpath);
771 if (addremove != '+')
772 fill_filespec(one, sha1, mode);
773 if (addremove != '-')
774 fill_filespec(two, sha1, mode);
776 diff_queue(&diff_queued_diff, one, two);
779 void diff_helper_input(unsigned old_mode,
781 const unsigned char *old_sha1,
782 const unsigned char *new_sha1,
783 const char *old_path,
786 const char *new_path)
788 struct diff_filespec *one, *two;
789 struct diff_filepair *dp;
791 one = alloc_filespec(old_path);
792 two = alloc_filespec(new_path);
794 fill_filespec(one, old_sha1, old_mode);
796 fill_filespec(two, new_sha1, new_mode);
797 dp = diff_queue(&diff_queued_diff, one, two);
802 void diff_change(unsigned old_mode, unsigned new_mode,
803 const unsigned char *old_sha1,
804 const unsigned char *new_sha1,
805 const char *base, const char *path)
807 char concatpath[PATH_MAX];
808 struct diff_filespec *one, *two;
812 const unsigned char *tmp_c;
813 tmp = old_mode; old_mode = new_mode; new_mode = tmp;
814 tmp_c = old_sha1; old_sha1 = new_sha1; new_sha1 = tmp_c;
816 if (!path) path = "";
817 sprintf(concatpath, "%s%s", base, path);
818 one = alloc_filespec(concatpath);
819 two = alloc_filespec(concatpath);
820 fill_filespec(one, old_sha1, old_mode);
821 fill_filespec(two, new_sha1, new_mode);
823 diff_queue(&diff_queued_diff, one, two);
826 void diff_unmerge(const char *path)
828 struct diff_filespec *one, *two;
829 one = alloc_filespec(path);
830 two = alloc_filespec(path);
831 diff_queue(&diff_queued_diff, one, two);