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;
16 static const char *external_diff(void)
18 static const char *external_diff_cmd = NULL;
19 static int done_preparing = 0;
22 return external_diff_cmd;
25 * Default values above are meant to match the
26 * Linux kernel development style. Examples of
27 * alternative styles you can specify via environment
32 if (gitenv("GIT_EXTERNAL_DIFF"))
33 external_diff_cmd = gitenv("GIT_EXTERNAL_DIFF");
35 /* In case external diff fails... */
36 diff_opts = gitenv("GIT_DIFF_OPTS") ? : diff_opts;
39 return external_diff_cmd;
42 /* Help to copy the thing properly quoted for the shell safety.
43 * any single quote is replaced with '\'', and the caller is
44 * expected to enclose the result within a single quote pair.
47 * original sq_expand result
48 * name ==> name ==> 'name'
49 * a b ==> a b ==> 'a b'
50 * a'b ==> a'\''b ==> 'a'\''b'
52 static char *sq_expand(const char *src)
54 static char *buf = NULL;
59 /* count bytes needed to store the quoted string. */
60 for (cnt = 1, cp = src; *cp; cnt++, cp++)
66 while ((c = *src++)) {
70 bp = strcpy(bp, "'\\''");
78 static struct diff_tempfile {
79 const char *name; /* filename external diff should read from */
85 static void builtin_diff(const char *name_a,
87 struct diff_tempfile *temp,
90 int i, next_at, cmd_size;
91 const char *diff_cmd = "diff -L'%s%s' -L'%s%s'";
92 const char *diff_arg = "'%s' '%s'||:"; /* "||:" is to return 0 */
93 const char *input_name_sq[2];
96 const char *name_sq[2];
99 name_sq[0] = sq_expand(name_a);
100 name_sq[1] = sq_expand(name_b);
102 /* diff_cmd and diff_arg have 6 %s in total which makes
103 * the sum of these strings 12 bytes larger than required.
104 * we use 2 spaces around diff-opts, and we need to count
105 * terminating NUL, so we subtract 9 here.
107 cmd_size = (strlen(diff_cmd) + strlen(diff_opts) +
108 strlen(diff_arg) - 9);
109 for (i = 0; i < 2; i++) {
110 input_name_sq[i] = sq_expand(temp[i].name);
111 if (!strcmp(temp[i].name, "/dev/null")) {
112 path0[i] = "/dev/null";
115 path0[i] = i ? "b/" : "a/";
116 path1[i] = name_sq[i];
118 cmd_size += (strlen(path0[i]) + strlen(path1[i]) +
119 strlen(input_name_sq[i]));
122 cmd = xmalloc(cmd_size);
125 next_at += snprintf(cmd+next_at, cmd_size-next_at,
127 path0[0], path1[0], path0[1], path1[1]);
128 next_at += snprintf(cmd+next_at, cmd_size-next_at,
130 next_at += snprintf(cmd+next_at, cmd_size-next_at,
131 diff_arg, input_name_sq[0], input_name_sq[1]);
133 printf("diff --git a/%s b/%s\n", name_a, name_b);
135 printf("new file mode %s\n", temp[1].mode);
136 else if (!path1[1][0])
137 printf("deleted file mode %s\n", temp[0].mode);
139 if (strcmp(temp[0].mode, temp[1].mode)) {
140 printf("old mode %s\n", temp[0].mode);
141 printf("new mode %s\n", temp[1].mode);
143 if (xfrm_msg && xfrm_msg[0])
144 fputs(xfrm_msg, stdout);
146 if (strncmp(temp[0].mode, temp[1].mode, 3))
147 /* we do not run diff between different kind
153 execlp("/bin/sh","sh", "-c", cmd, NULL);
156 struct diff_filespec *alloc_filespec(const char *path)
158 int namelen = strlen(path);
159 struct diff_filespec *spec = xmalloc(sizeof(*spec) + namelen + 1);
160 spec->path = (char *)(spec + 1);
161 strcpy(spec->path, path);
162 spec->should_free = spec->should_munmap = 0;
163 spec->xfrm_flags = 0;
167 memset(spec->sha1, 0, 20);
171 void fill_filespec(struct diff_filespec *spec, const unsigned char *sha1,
174 if (mode) { /* just playing defensive */
176 memcpy(spec->sha1, sha1, 20);
177 spec->sha1_valid = !!memcmp(sha1, null_sha1, 20);
182 * Given a name and sha1 pair, if the dircache tells us the file in
183 * the work tree has that object contents, return true, so that
184 * prepare_temp_file() does not have to inflate and extract.
186 static int work_tree_matches(const char *name, const unsigned char *sha1)
188 struct cache_entry *ce;
192 /* We do not read the cache ourselves here, because the
193 * benchmark with my previous version that always reads cache
194 * shows that it makes things worse for diff-tree comparing
195 * two linux-2.6 kernel trees in an already checked out work
196 * tree. This is because most diff-tree comparisons deal with
197 * only a small number of files, while reading the cache is
198 * expensive for a large project, and its cost outweighs the
199 * savings we get by not inflating the object to a temporary
200 * file. Practically, this code only helps when we are used
201 * by diff-cache --cached, which does read the cache before
208 pos = cache_name_pos(name, len);
211 ce = active_cache[pos];
212 if ((lstat(name, &st) < 0) ||
213 !S_ISREG(st.st_mode) || /* careful! */
214 ce_match_stat(ce, &st) ||
215 memcmp(sha1, ce->sha1, 20))
217 /* we return 1 only when we can stat, it is a regular file,
218 * stat information matches, and sha1 recorded in the cache
219 * matches. I.e. we know the file in the work tree really is
220 * the same as the <name, sha1> pair.
226 * While doing rename detection and pickaxe operation, we may need to
227 * grab the data for the blob (or file) for our own in-core comparison.
228 * diff_filespec has data and size fields for this purpose.
230 int diff_populate_filespec(struct diff_filespec *s)
233 if (!DIFF_FILE_VALID(s))
234 die("internal error: asking to populate invalid file.");
235 if (S_ISDIR(s->mode))
240 if (!s->sha1_valid ||
241 work_tree_matches(s->path, s->sha1)) {
244 if (lstat(s->path, &st) < 0) {
245 if (errno == ENOENT) {
254 s->size = st.st_size;
257 if (S_ISLNK(st.st_mode)) {
259 s->data = xmalloc(s->size);
261 ret = readlink(s->path, s->data, s->size);
268 fd = open(s->path, O_RDONLY);
271 s->data = mmap(NULL, s->size, PROT_READ, MAP_PRIVATE, fd, 0);
272 s->should_munmap = 1;
277 s->data = read_sha1_file(s->sha1, type, &s->size);
283 void diff_free_filespec_data(struct diff_filespec *s)
287 else if (s->should_munmap)
288 munmap(s->data, s->size);
289 s->should_free = s->should_munmap = 0;
293 static void prep_temp_blob(struct diff_tempfile *temp,
301 strcpy(temp->tmp_path, ".diff_XXXXXX");
302 fd = mkstemp(temp->tmp_path);
304 die("unable to create temp-file");
305 if (write(fd, blob, size) != size)
306 die("unable to write temp-file");
308 temp->name = temp->tmp_path;
309 strcpy(temp->hex, sha1_to_hex(sha1));
311 sprintf(temp->mode, "%06o", mode);
314 static void prepare_temp_file(const char *name,
315 struct diff_tempfile *temp,
316 struct diff_filespec *one)
318 if (!DIFF_FILE_VALID(one)) {
320 /* A '-' entry produces this for file-2, and
321 * a '+' entry produces this for file-1.
323 temp->name = "/dev/null";
324 strcpy(temp->hex, ".");
325 strcpy(temp->mode, ".");
329 if (!one->sha1_valid ||
330 work_tree_matches(name, one->sha1)) {
332 if (lstat(name, &st) < 0) {
334 goto not_a_valid_file;
335 die("stat(%s): %s", name, strerror(errno));
337 if (S_ISLNK(st.st_mode)) {
339 char *buf, buf_[1024];
340 buf = ((sizeof(buf_) < st.st_size) ?
341 xmalloc(st.st_size) : buf_);
342 ret = readlink(name, buf, st.st_size);
344 die("readlink(%s)", name);
345 prep_temp_blob(temp, buf, st.st_size,
347 one->sha1 : null_sha1),
349 one->mode : S_IFLNK));
352 /* we can borrow from the file in the work tree */
354 if (!one->sha1_valid)
355 strcpy(temp->hex, sha1_to_hex(null_sha1));
357 strcpy(temp->hex, sha1_to_hex(one->sha1));
358 sprintf(temp->mode, "%06o",
359 S_IFREG |ce_permissions(st.st_mode));
364 if (diff_populate_filespec(one))
365 die("cannot read data blob for %s", one->path);
366 prep_temp_blob(temp, one->data, one->size,
367 one->sha1, one->mode);
371 static void remove_tempfile(void)
375 for (i = 0; i < 2; i++)
376 if (diff_temp[i].name == diff_temp[i].tmp_path) {
377 unlink(diff_temp[i].name);
378 diff_temp[i].name = NULL;
382 static void remove_tempfile_on_signal(int signo)
387 /* An external diff command takes:
389 * diff-cmd name infile1 infile1-sha1 infile1-mode \
390 * infile2 infile2-sha1 infile2-mode [ rename-to ]
393 static void run_external_diff(const char *name,
395 struct diff_filespec *one,
396 struct diff_filespec *two,
397 const char *xfrm_msg)
399 struct diff_tempfile *temp = diff_temp;
402 static int atexit_asked = 0;
405 prepare_temp_file(name, &temp[0], one);
406 prepare_temp_file(other ? : name, &temp[1], two);
407 if (! atexit_asked &&
408 (temp[0].name == temp[0].tmp_path ||
409 temp[1].name == temp[1].tmp_path)) {
411 atexit(remove_tempfile);
413 signal(SIGINT, remove_tempfile_on_signal);
419 die("unable to fork");
421 const char *pgm = external_diff();
424 const char *exec_arg[10];
425 const char **arg = &exec_arg[0];
428 *arg++ = temp[0].name;
429 *arg++ = temp[0].hex;
430 *arg++ = temp[0].mode;
431 *arg++ = temp[1].name;
432 *arg++ = temp[1].hex;
433 *arg++ = temp[1].mode;
439 execvp(pgm, (char *const*) exec_arg);
442 execlp(pgm, pgm, name, NULL);
445 * otherwise we use the built-in one.
448 builtin_diff(name, other ? : name, temp, xfrm_msg);
450 printf("* Unmerged path %s\n", name);
453 if (waitpid(pid, &status, 0) < 0 ||
454 !WIFEXITED(status) || WEXITSTATUS(status)) {
455 /* Earlier we did not check the exit status because
456 * diff exits non-zero if files are different, and
457 * we are not interested in knowing that. It was a
458 * mistake which made it harder to quit a diff-*
459 * session that uses the git-apply-patch-script as
460 * the GIT_EXTERNAL_DIFF. A custom GIT_EXTERNAL_DIFF
461 * should also exit non-zero only when it wants to
462 * abort the entire diff-* session.
465 fprintf(stderr, "external diff died, stopping at %s.\n", name);
471 void diff_setup(int reverse_diff_)
473 reverse_diff = reverse_diff_;
476 struct diff_queue_struct diff_queued_diff;
478 void diff_q(struct diff_queue_struct *queue, struct diff_filepair *dp)
480 if (queue->alloc <= queue->nr) {
481 queue->alloc = alloc_nr(queue->alloc);
482 queue->queue = xrealloc(queue->queue,
483 sizeof(dp) * queue->alloc);
485 queue->queue[queue->nr++] = dp;
488 struct diff_filepair *diff_queue(struct diff_queue_struct *queue,
489 struct diff_filespec *one,
490 struct diff_filespec *two)
492 struct diff_filepair *dp = xmalloc(sizeof(*dp));
496 dp->orig_order = queue->nr;
502 static void diff_flush_raw(struct diff_filepair *p,
503 int line_termination,
504 int inter_name_termination)
511 sprintf(status, "%c%1d", p->status, p->score);
515 status[0] = p->status;
519 printf(":%06o %06o %s ",
520 p->one->mode, p->two->mode, sha1_to_hex(p->one->sha1));
522 sha1_to_hex(p->two->sha1),
524 inter_name_termination,
527 printf("%c%s", inter_name_termination, p->two->path);
528 putchar(line_termination);
531 int diff_unmodified_pair(struct diff_filepair *p)
533 /* This function is written stricter than necessary to support
534 * the currently implemented transformers, but the idea is to
535 * let transformers to produce diff_filepairs any way they want,
536 * and filter and clean them up here before producing the output.
538 struct diff_filespec *one, *two;
540 if (DIFF_PAIR_UNMERGED(p))
541 return 0; /* unmerged is interesting */
546 /* deletion, addition, mode change and renames are all interesting. */
547 if (DIFF_FILE_VALID(one) != DIFF_FILE_VALID(two) ||
548 (one->mode != two->mode) ||
549 strcmp(one->path, two->path))
552 /* both are valid and point at the same path. that is, we are
553 * dealing with a change.
555 if (one->sha1_valid && two->sha1_valid &&
556 !memcmp(one->sha1, two->sha1, sizeof(one->sha1)))
557 return 1; /* no change */
558 if (!one->sha1_valid && !two->sha1_valid)
559 return 1; /* both look at the same file on the filesystem. */
563 static void diff_flush_patch(struct diff_filepair *p)
565 const char *name, *other;
566 char msg_[PATH_MAX*2+200], *msg;
568 if (diff_unmodified_pair(p))
572 other = (strcmp(name, p->two->path) ? p->two->path : NULL);
573 if ((DIFF_FILE_VALID(p->one) && S_ISDIR(p->one->mode)) ||
574 (DIFF_FILE_VALID(p->two) && S_ISDIR(p->two->mode)))
575 return; /* no tree diffs in patch format */
580 "similarity index %d%%\n"
583 (int)(0.5 + p->score * 100.0/MAX_SCORE),
584 p->one->path, p->two->path);
589 "similarity index %d%%\n"
592 (int)(0.5 + p->score * 100.0/MAX_SCORE),
593 p->one->path, p->two->path);
600 if (DIFF_PAIR_UNMERGED(p))
601 run_external_diff(name, NULL, NULL, NULL, NULL);
603 run_external_diff(name, other, p->one, p->two, msg);
606 int diff_needs_to_stay(struct diff_queue_struct *q, int i,
607 struct diff_filespec *it)
609 /* If it will be used in later entry (either stay or used
610 * as the source of rename/copy), we need to copy, not rename.
613 struct diff_filepair *p = q->queue[i++];
614 if (!DIFF_FILE_VALID(p->two))
615 continue; /* removed is fine */
616 if (strcmp(p->one->path, it->path))
617 continue; /* not relevant */
619 /* p has its src set to *it and it is not a delete;
620 * it will be used for in-place change, rename/copy,
621 * or just stays there. We cannot rename it out.
628 int diff_queue_is_empty(void)
630 struct diff_queue_struct *q = &diff_queued_diff;
634 static void diff_resolve_rename_copy(void)
637 struct diff_queue_struct *q = &diff_queued_diff;
638 for (i = 0; i < q->nr; i++) {
639 struct diff_filepair *p = q->queue[i];
641 if (DIFF_PAIR_UNMERGED(p))
643 else if (!DIFF_FILE_VALID((p)->one))
645 else if (!DIFF_FILE_VALID((p)->two)) {
646 /* maybe earlier one said 'R', meaning
647 * it will take it, in which case we do
648 * not need to keep 'D'.
651 for (j = 0; j < i; j++) {
652 struct diff_filepair *pp = q->queue[j];
653 if (pp->status == 'R' &&
654 !strcmp(pp->one->path, p->one->path))
661 else if (strcmp(p->one->path, p->two->path)) {
662 /* This is rename or copy. Which one is it? */
663 if (diff_needs_to_stay(q, i+1, p->one))
668 else if (memcmp(p->one->sha1, p->two->sha1, 20))
671 /* we do not need this one */
677 void diff_flush(int diff_output_style, int resolve_rename_copy)
679 struct diff_queue_struct *q = &diff_queued_diff;
681 int line_termination = '\n';
682 int inter_name_termination = '\t';
684 if (diff_output_style == DIFF_FORMAT_MACHINE)
685 line_termination = inter_name_termination = 0;
686 if (resolve_rename_copy)
687 diff_resolve_rename_copy();
689 for (i = 0; i < q->nr; i++) {
690 struct diff_filepair *p = q->queue[i];
693 switch (diff_output_style) {
694 case DIFF_FORMAT_PATCH:
697 case DIFF_FORMAT_HUMAN:
698 case DIFF_FORMAT_MACHINE:
699 diff_flush_raw(p, line_termination,
700 inter_name_termination);
704 for (i = 0; i < q->nr; i++) {
705 struct diff_filepair *p = q->queue[i];
706 diff_free_filespec_data(p->one);
707 diff_free_filespec_data(p->two);
712 q->nr = q->alloc = 0;
715 void diff_addremove(int addremove, unsigned mode,
716 const unsigned char *sha1,
717 const char *base, const char *path)
719 char concatpath[PATH_MAX];
720 struct diff_filespec *one, *two;
722 /* This may look odd, but it is a preparation for
723 * feeding "there are unchanged files which should
724 * not produce diffs, but when you are doing copy
725 * detection you would need them, so here they are"
726 * entries to the diff-core. They will be prefixed
727 * with something like '=' or '*' (I haven't decided
728 * which but should not make any difference).
729 * Feeding the same new and old to diff_change()
730 * also has the same effect.
731 * Before the final output happens, they are pruned after
732 * merged into rename/copy pairs as appropriate.
735 addremove = (addremove == '+' ? '-' :
736 addremove == '-' ? '+' : addremove);
738 if (!path) path = "";
739 sprintf(concatpath, "%s%s", base, path);
740 one = alloc_filespec(concatpath);
741 two = alloc_filespec(concatpath);
743 if (addremove != '+')
744 fill_filespec(one, sha1, mode);
745 if (addremove != '-')
746 fill_filespec(two, sha1, mode);
748 diff_queue(&diff_queued_diff, one, two);
751 void diff_helper_input(unsigned old_mode,
753 const unsigned char *old_sha1,
754 const unsigned char *new_sha1,
755 const char *old_path,
758 const char *new_path)
760 struct diff_filespec *one, *two;
761 struct diff_filepair *dp;
763 one = alloc_filespec(old_path);
764 two = alloc_filespec(new_path);
766 fill_filespec(one, old_sha1, old_mode);
768 fill_filespec(two, new_sha1, new_mode);
769 dp = diff_queue(&diff_queued_diff, one, two);
774 void diff_change(unsigned old_mode, unsigned new_mode,
775 const unsigned char *old_sha1,
776 const unsigned char *new_sha1,
777 const char *base, const char *path)
779 char concatpath[PATH_MAX];
780 struct diff_filespec *one, *two;
784 const unsigned char *tmp_c;
785 tmp = old_mode; old_mode = new_mode; new_mode = tmp;
786 tmp_c = old_sha1; old_sha1 = new_sha1; new_sha1 = tmp_c;
788 if (!path) path = "";
789 sprintf(concatpath, "%s%s", base, path);
790 one = alloc_filespec(concatpath);
791 two = alloc_filespec(concatpath);
792 fill_filespec(one, old_sha1, old_mode);
793 fill_filespec(two, new_sha1, new_mode);
795 diff_queue(&diff_queued_diff, one, two);
798 void diff_unmerge(const char *path)
800 struct diff_filespec *one, *two;
801 one = alloc_filespec(path);
802 two = alloc_filespec(path);
803 diff_queue(&diff_queued_diff, one, two);