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[git] / diff.c
1 /*
2  * Copyright (C) 2005 Junio C Hamano
3  */
4 #include <sys/types.h>
5 #include <sys/wait.h>
6 #include <signal.h>
7 #include "cache.h"
8 #include "quote.h"
9 #include "diff.h"
10 #include "diffcore.h"
11
12 static const char *diff_opts = "-pu";
13 static unsigned char null_sha1[20] = { 0, };
14
15 static int use_size_cache;
16
17 static const char *external_diff(void)
18 {
19         static const char *external_diff_cmd = NULL;
20         static int done_preparing = 0;
21         const char *env_diff_opts;
22
23         if (done_preparing)
24                 return external_diff_cmd;
25
26         /*
27          * Default values above are meant to match the
28          * Linux kernel development style.  Examples of
29          * alternative styles you can specify via environment
30          * variables are:
31          *
32          * GIT_DIFF_OPTS="-c";
33          */
34         external_diff_cmd = getenv("GIT_EXTERNAL_DIFF");
35
36         /* In case external diff fails... */
37         env_diff_opts = getenv("GIT_DIFF_OPTS");
38         if (env_diff_opts) diff_opts = env_diff_opts;
39
40         done_preparing = 1;
41         return external_diff_cmd;
42 }
43
44 #define TEMPFILE_PATH_LEN               50
45
46 static struct diff_tempfile {
47         const char *name; /* filename external diff should read from */
48         char hex[41];
49         char mode[10];
50         char tmp_path[TEMPFILE_PATH_LEN];
51 } diff_temp[2];
52
53 static int count_lines(const char *filename)
54 {
55         FILE *in;
56         int count, ch, completely_empty = 1, nl_just_seen = 0;
57         in = fopen(filename, "r");
58         count = 0;
59         while ((ch = fgetc(in)) != EOF)
60                 if (ch == '\n') {
61                         count++;
62                         nl_just_seen = 1;
63                         completely_empty = 0;
64                 }
65                 else {
66                         nl_just_seen = 0;
67                         completely_empty = 0;
68                 }
69         fclose(in);
70         if (completely_empty)
71                 return 0;
72         if (!nl_just_seen)
73                 count++; /* no trailing newline */
74         return count;
75 }
76
77 static void print_line_count(int count)
78 {
79         switch (count) {
80         case 0:
81                 printf("0,0");
82                 break;
83         case 1:
84                 printf("1");
85                 break;
86         default:
87                 printf("1,%d", count);
88                 break;
89         }
90 }
91
92 static void copy_file(int prefix, const char *filename)
93 {
94         FILE *in;
95         int ch, nl_just_seen = 1;
96         in = fopen(filename, "r");
97         while ((ch = fgetc(in)) != EOF) {
98                 if (nl_just_seen)
99                         putchar(prefix);
100                 putchar(ch);
101                 if (ch == '\n')
102                         nl_just_seen = 1;
103                 else
104                         nl_just_seen = 0;
105         }
106         fclose(in);
107         if (!nl_just_seen)
108                 printf("\n\\ No newline at end of file\n");
109 }
110
111 static void emit_rewrite_diff(const char *name_a,
112                               const char *name_b,
113                               struct diff_tempfile *temp)
114 {
115         /* Use temp[i].name as input, name_a and name_b as labels */
116         int lc_a, lc_b;
117         lc_a = count_lines(temp[0].name);
118         lc_b = count_lines(temp[1].name);
119         printf("--- %s\n+++ %s\n@@ -", name_a, name_b);
120         print_line_count(lc_a);
121         printf(" +");
122         print_line_count(lc_b);
123         printf(" @@\n");
124         if (lc_a)
125                 copy_file('-', temp[0].name);
126         if (lc_b)
127                 copy_file('+', temp[1].name);
128 }
129
130 static void builtin_diff(const char *name_a,
131                          const char *name_b,
132                          struct diff_tempfile *temp,
133                          const char *xfrm_msg,
134                          int complete_rewrite)
135 {
136         int i, next_at, cmd_size;
137         const char *const diff_cmd = "diff -L%s%s -L%s%s";
138         const char *const diff_arg  = "%s %s||:"; /* "||:" is to return 0 */
139         const char *input_name_sq[2];
140         const char *path0[2];
141         const char *path1[2];
142         const char *name_sq[2];
143         char *cmd;
144
145         name_sq[0] = sq_quote(name_a);
146         name_sq[1] = sq_quote(name_b);
147
148         /* diff_cmd and diff_arg have 6 %s in total which makes
149          * the sum of these strings 12 bytes larger than required.
150          * we use 2 spaces around diff-opts, and we need to count
151          * terminating NUL, so we subtract 9 here.
152          */
153         cmd_size = (strlen(diff_cmd) + strlen(diff_opts) +
154                         strlen(diff_arg) - 9);
155         for (i = 0; i < 2; i++) {
156                 input_name_sq[i] = sq_quote(temp[i].name);
157                 if (!strcmp(temp[i].name, "/dev/null")) {
158                         path0[i] = "/dev/null";
159                         path1[i] = "";
160                 } else {
161                         path0[i] = i ? "b/" : "a/";
162                         path1[i] = name_sq[i];
163                 }
164                 cmd_size += (strlen(path0[i]) + strlen(path1[i]) +
165                              strlen(input_name_sq[i]));
166         }
167
168         cmd = xmalloc(cmd_size);
169
170         next_at = 0;
171         next_at += snprintf(cmd+next_at, cmd_size-next_at,
172                             diff_cmd,
173                             path0[0], path1[0], path0[1], path1[1]);
174         next_at += snprintf(cmd+next_at, cmd_size-next_at,
175                             " %s ", diff_opts);
176         next_at += snprintf(cmd+next_at, cmd_size-next_at,
177                             diff_arg, input_name_sq[0], input_name_sq[1]);
178
179         printf("diff --git a/%s b/%s\n", name_a, name_b);
180         if (!path1[0][0]) {
181                 printf("new file mode %s\n", temp[1].mode);
182                 if (xfrm_msg && xfrm_msg[0])
183                         puts(xfrm_msg);
184         }
185         else if (!path1[1][0]) {
186                 printf("deleted file mode %s\n", temp[0].mode);
187                 if (xfrm_msg && xfrm_msg[0])
188                         puts(xfrm_msg);
189         }
190         else {
191                 if (strcmp(temp[0].mode, temp[1].mode)) {
192                         printf("old mode %s\n", temp[0].mode);
193                         printf("new mode %s\n", temp[1].mode);
194                 }
195                 if (xfrm_msg && xfrm_msg[0])
196                         puts(xfrm_msg);
197                 if (strncmp(temp[0].mode, temp[1].mode, 3))
198                         /* we do not run diff between different kind
199                          * of objects.
200                          */
201                         exit(0);
202                 if (complete_rewrite) {
203                         fflush(NULL);
204                         emit_rewrite_diff(name_a, name_b, temp);
205                         exit(0);
206                 }
207         }
208         fflush(NULL);
209         execlp("/bin/sh","sh", "-c", cmd, NULL);
210 }
211
212 struct diff_filespec *alloc_filespec(const char *path)
213 {
214         int namelen = strlen(path);
215         struct diff_filespec *spec = xmalloc(sizeof(*spec) + namelen + 1);
216
217         memset(spec, 0, sizeof(*spec));
218         spec->path = (char *)(spec + 1);
219         memcpy(spec->path, path, namelen+1);
220         return spec;
221 }
222
223 void fill_filespec(struct diff_filespec *spec, const unsigned char *sha1,
224                    unsigned short mode)
225 {
226         if (mode) {
227                 spec->mode = DIFF_FILE_CANON_MODE(mode);
228                 memcpy(spec->sha1, sha1, 20);
229                 spec->sha1_valid = !!memcmp(sha1, null_sha1, 20);
230         }
231 }
232
233 /*
234  * Given a name and sha1 pair, if the dircache tells us the file in
235  * the work tree has that object contents, return true, so that
236  * prepare_temp_file() does not have to inflate and extract.
237  */
238 static int work_tree_matches(const char *name, const unsigned char *sha1)
239 {
240         struct cache_entry *ce;
241         struct stat st;
242         int pos, len;
243
244         /* We do not read the cache ourselves here, because the
245          * benchmark with my previous version that always reads cache
246          * shows that it makes things worse for diff-tree comparing
247          * two linux-2.6 kernel trees in an already checked out work
248          * tree.  This is because most diff-tree comparisons deal with
249          * only a small number of files, while reading the cache is
250          * expensive for a large project, and its cost outweighs the
251          * savings we get by not inflating the object to a temporary
252          * file.  Practically, this code only helps when we are used
253          * by diff-cache --cached, which does read the cache before
254          * calling us.
255          */
256         if (!active_cache)
257                 return 0;
258
259         len = strlen(name);
260         pos = cache_name_pos(name, len);
261         if (pos < 0)
262                 return 0;
263         ce = active_cache[pos];
264         if ((lstat(name, &st) < 0) ||
265             !S_ISREG(st.st_mode) || /* careful! */
266             ce_match_stat(ce, &st) ||
267             memcmp(sha1, ce->sha1, 20))
268                 return 0;
269         /* we return 1 only when we can stat, it is a regular file,
270          * stat information matches, and sha1 recorded in the cache
271          * matches.  I.e. we know the file in the work tree really is
272          * the same as the <name, sha1> pair.
273          */
274         return 1;
275 }
276
277 static struct sha1_size_cache {
278         unsigned char sha1[20];
279         unsigned long size;
280 } **sha1_size_cache;
281 static int sha1_size_cache_nr, sha1_size_cache_alloc;
282
283 static struct sha1_size_cache *locate_size_cache(unsigned char *sha1,
284                                                  int find_only,
285                                                  unsigned long size)
286 {
287         int first, last;
288         struct sha1_size_cache *e;
289
290         first = 0;
291         last = sha1_size_cache_nr;
292         while (last > first) {
293                 int cmp, next = (last + first) >> 1;
294                 e = sha1_size_cache[next];
295                 cmp = memcmp(e->sha1, sha1, 20);
296                 if (!cmp)
297                         return e;
298                 if (cmp < 0) {
299                         last = next;
300                         continue;
301                 }
302                 first = next+1;
303         }
304         /* not found */
305         if (find_only)
306                 return NULL;
307         /* insert to make it at "first" */
308         if (sha1_size_cache_alloc <= sha1_size_cache_nr) {
309                 sha1_size_cache_alloc = alloc_nr(sha1_size_cache_alloc);
310                 sha1_size_cache = xrealloc(sha1_size_cache,
311                                            sha1_size_cache_alloc *
312                                            sizeof(*sha1_size_cache));
313         }
314         sha1_size_cache_nr++;
315         if (first < sha1_size_cache_nr)
316                 memmove(sha1_size_cache + first + 1, sha1_size_cache + first,
317                         (sha1_size_cache_nr - first - 1) *
318                         sizeof(*sha1_size_cache));
319         e = xmalloc(sizeof(struct sha1_size_cache));
320         sha1_size_cache[first] = e;
321         memcpy(e->sha1, sha1, 20);
322         e->size = size;
323         return e;
324 }
325
326 /*
327  * While doing rename detection and pickaxe operation, we may need to
328  * grab the data for the blob (or file) for our own in-core comparison.
329  * diff_filespec has data and size fields for this purpose.
330  */
331 int diff_populate_filespec(struct diff_filespec *s, int size_only)
332 {
333         int err = 0;
334         if (!DIFF_FILE_VALID(s))
335                 die("internal error: asking to populate invalid file.");
336         if (S_ISDIR(s->mode))
337                 return -1;
338
339         if (!use_size_cache)
340                 size_only = 0;
341
342         if (s->data)
343                 return err;
344         if (!s->sha1_valid ||
345             work_tree_matches(s->path, s->sha1)) {
346                 struct stat st;
347                 int fd;
348                 if (lstat(s->path, &st) < 0) {
349                         if (errno == ENOENT) {
350                         err_empty:
351                                 err = -1;
352                         empty:
353                                 s->data = "";
354                                 s->size = 0;
355                                 return err;
356                         }
357                 }
358                 s->size = st.st_size;
359                 if (!s->size)
360                         goto empty;
361                 if (size_only)
362                         return 0;
363                 if (S_ISLNK(st.st_mode)) {
364                         int ret;
365                         s->data = xmalloc(s->size);
366                         s->should_free = 1;
367                         ret = readlink(s->path, s->data, s->size);
368                         if (ret < 0) {
369                                 free(s->data);
370                                 goto err_empty;
371                         }
372                         return 0;
373                 }
374                 fd = open(s->path, O_RDONLY);
375                 if (fd < 0)
376                         goto err_empty;
377                 s->data = mmap(NULL, s->size, PROT_READ, MAP_PRIVATE, fd, 0);
378                 close(fd);
379                 if (s->data == MAP_FAILED)
380                         goto err_empty;
381                 s->should_munmap = 1;
382         }
383         else {
384                 char type[20];
385                 struct sha1_size_cache *e;
386
387                 if (size_only) {
388                         e = locate_size_cache(s->sha1, 1, 0);
389                         if (e) {
390                                 s->size = e->size;
391                                 return 0;
392                         }
393                         if (!sha1_object_info(s->sha1, type, &s->size))
394                                 locate_size_cache(s->sha1, 0, s->size);
395                 }
396                 else {
397                         s->data = read_sha1_file(s->sha1, type, &s->size);
398                         s->should_free = 1;
399                 }
400         }
401         return 0;
402 }
403
404 void diff_free_filespec_data(struct diff_filespec *s)
405 {
406         if (s->should_free)
407                 free(s->data);
408         else if (s->should_munmap)
409                 munmap(s->data, s->size);
410         s->should_free = s->should_munmap = 0;
411         s->data = NULL;
412 }
413
414 static void prep_temp_blob(struct diff_tempfile *temp,
415                            void *blob,
416                            unsigned long size,
417                            unsigned char *sha1,
418                            int mode)
419 {
420         int fd;
421
422         fd = git_mkstemp(temp->tmp_path, TEMPFILE_PATH_LEN, ".diff_XXXXXX");
423         if (fd < 0)
424                 die("unable to create temp-file");
425         if (write(fd, blob, size) != size)
426                 die("unable to write temp-file");
427         close(fd);
428         temp->name = temp->tmp_path;
429         strcpy(temp->hex, sha1_to_hex(sha1));
430         temp->hex[40] = 0;
431         sprintf(temp->mode, "%06o", mode);
432 }
433
434 static void prepare_temp_file(const char *name,
435                               struct diff_tempfile *temp,
436                               struct diff_filespec *one)
437 {
438         if (!DIFF_FILE_VALID(one)) {
439         not_a_valid_file:
440                 /* A '-' entry produces this for file-2, and
441                  * a '+' entry produces this for file-1.
442                  */
443                 temp->name = "/dev/null";
444                 strcpy(temp->hex, ".");
445                 strcpy(temp->mode, ".");
446                 return;
447         }
448
449         if (!one->sha1_valid ||
450             work_tree_matches(name, one->sha1)) {
451                 struct stat st;
452                 if (lstat(name, &st) < 0) {
453                         if (errno == ENOENT)
454                                 goto not_a_valid_file;
455                         die("stat(%s): %s", name, strerror(errno));
456                 }
457                 if (S_ISLNK(st.st_mode)) {
458                         int ret;
459                         char *buf, buf_[1024];
460                         buf = ((sizeof(buf_) < st.st_size) ?
461                                xmalloc(st.st_size) : buf_);
462                         ret = readlink(name, buf, st.st_size);
463                         if (ret < 0)
464                                 die("readlink(%s)", name);
465                         prep_temp_blob(temp, buf, st.st_size,
466                                        (one->sha1_valid ?
467                                         one->sha1 : null_sha1),
468                                        (one->sha1_valid ?
469                                         one->mode : S_IFLNK));
470                 }
471                 else {
472                         /* we can borrow from the file in the work tree */
473                         temp->name = name;
474                         if (!one->sha1_valid)
475                                 strcpy(temp->hex, sha1_to_hex(null_sha1));
476                         else
477                                 strcpy(temp->hex, sha1_to_hex(one->sha1));
478                         /* Even though we may sometimes borrow the
479                          * contents from the work tree, we always want
480                          * one->mode.  mode is trustworthy even when
481                          * !(one->sha1_valid), as long as
482                          * DIFF_FILE_VALID(one).
483                          */
484                         sprintf(temp->mode, "%06o", one->mode);
485                 }
486                 return;
487         }
488         else {
489                 if (diff_populate_filespec(one, 0))
490                         die("cannot read data blob for %s", one->path);
491                 prep_temp_blob(temp, one->data, one->size,
492                                one->sha1, one->mode);
493         }
494 }
495
496 static void remove_tempfile(void)
497 {
498         int i;
499
500         for (i = 0; i < 2; i++)
501                 if (diff_temp[i].name == diff_temp[i].tmp_path) {
502                         unlink(diff_temp[i].name);
503                         diff_temp[i].name = NULL;
504                 }
505 }
506
507 static void remove_tempfile_on_signal(int signo)
508 {
509         remove_tempfile();
510 }
511
512 /* An external diff command takes:
513  *
514  * diff-cmd name infile1 infile1-sha1 infile1-mode \
515  *               infile2 infile2-sha1 infile2-mode [ rename-to ]
516  *
517  */
518 static void run_external_diff(const char *pgm,
519                               const char *name,
520                               const char *other,
521                               struct diff_filespec *one,
522                               struct diff_filespec *two,
523                               const char *xfrm_msg,
524                               int complete_rewrite)
525 {
526         struct diff_tempfile *temp = diff_temp;
527         pid_t pid;
528         int status;
529         static int atexit_asked = 0;
530         const char *othername;
531
532         othername = (other? other : name);
533         if (one && two) {
534                 prepare_temp_file(name, &temp[0], one);
535                 prepare_temp_file(othername, &temp[1], two);
536                 if (! atexit_asked &&
537                     (temp[0].name == temp[0].tmp_path ||
538                      temp[1].name == temp[1].tmp_path)) {
539                         atexit_asked = 1;
540                         atexit(remove_tempfile);
541                 }
542                 signal(SIGINT, remove_tempfile_on_signal);
543         }
544
545         fflush(NULL);
546         pid = fork();
547         if (pid < 0)
548                 die("unable to fork");
549         if (!pid) {
550                 if (pgm) {
551                         if (one && two) {
552                                 const char *exec_arg[10];
553                                 const char **arg = &exec_arg[0];
554                                 *arg++ = pgm;
555                                 *arg++ = name;
556                                 *arg++ = temp[0].name;
557                                 *arg++ = temp[0].hex;
558                                 *arg++ = temp[0].mode;
559                                 *arg++ = temp[1].name;
560                                 *arg++ = temp[1].hex;
561                                 *arg++ = temp[1].mode;
562                                 if (other) {
563                                         *arg++ = other;
564                                         *arg++ = xfrm_msg;
565                                 }
566                                 *arg = NULL;
567                                 execvp(pgm, (char *const*) exec_arg);
568                         }
569                         else
570                                 execlp(pgm, pgm, name, NULL);
571                 }
572                 /*
573                  * otherwise we use the built-in one.
574                  */
575                 if (one && two)
576                         builtin_diff(name, othername, temp, xfrm_msg,
577                                      complete_rewrite);
578                 else
579                         printf("* Unmerged path %s\n", name);
580                 exit(0);
581         }
582         if (waitpid(pid, &status, 0) < 0 ||
583             !WIFEXITED(status) || WEXITSTATUS(status)) {
584                 /* Earlier we did not check the exit status because
585                  * diff exits non-zero if files are different, and
586                  * we are not interested in knowing that.  It was a
587                  * mistake which made it harder to quit a diff-*
588                  * session that uses the git-apply-patch-script as
589                  * the GIT_EXTERNAL_DIFF.  A custom GIT_EXTERNAL_DIFF
590                  * should also exit non-zero only when it wants to
591                  * abort the entire diff-* session.
592                  */
593                 remove_tempfile();
594                 fprintf(stderr, "external diff died, stopping at %s.\n", name);
595                 exit(1);
596         }
597         remove_tempfile();
598 }
599
600 static void run_diff(struct diff_filepair *p)
601 {
602         const char *pgm = external_diff();
603         char msg_[PATH_MAX*2+200], *xfrm_msg;
604         struct diff_filespec *one;
605         struct diff_filespec *two;
606         const char *name;
607         const char *other;
608         int complete_rewrite = 0;
609
610         if (DIFF_PAIR_UNMERGED(p)) {
611                 /* unmerged */
612                 run_external_diff(pgm, p->one->path, NULL, NULL, NULL, NULL,
613                                   0);
614                 return;
615         }
616
617         name = p->one->path;
618         other = (strcmp(name, p->two->path) ? p->two->path : NULL);
619         one = p->one; two = p->two;
620         switch (p->status) {
621         case DIFF_STATUS_COPIED:
622                 sprintf(msg_,
623                         "similarity index %d%%\n"
624                         "copy from %s\n"
625                         "copy to %s",
626                         (int)(0.5 + p->score * 100.0/MAX_SCORE),
627                         name, other);
628                 xfrm_msg = msg_;
629                 break;
630         case DIFF_STATUS_RENAMED:
631                 sprintf(msg_,
632                         "similarity index %d%%\n"
633                         "rename from %s\n"
634                         "rename to %s",
635                         (int)(0.5 + p->score * 100.0/MAX_SCORE),
636                         name, other);
637                 xfrm_msg = msg_;
638                 break;
639         case DIFF_STATUS_MODIFIED:
640                 if (p->score) {
641                         sprintf(msg_,
642                                 "dissimilarity index %d%%",
643                                 (int)(0.5 + p->score * 100.0/MAX_SCORE));
644                         xfrm_msg = msg_;
645                         complete_rewrite = 1;
646                         break;
647                 }
648                 /* fallthru */
649         default:
650                 xfrm_msg = NULL;
651         }
652
653         if (!pgm &&
654             DIFF_FILE_VALID(one) && DIFF_FILE_VALID(two) &&
655             (S_IFMT & one->mode) != (S_IFMT & two->mode)) {
656                 /* a filepair that changes between file and symlink
657                  * needs to be split into deletion and creation.
658                  */
659                 struct diff_filespec *null = alloc_filespec(two->path);
660                 run_external_diff(NULL, name, other, one, null, xfrm_msg, 0);
661                 free(null);
662                 null = alloc_filespec(one->path);
663                 run_external_diff(NULL, name, other, null, two, xfrm_msg, 0);
664                 free(null);
665         }
666         else
667                 run_external_diff(pgm, name, other, one, two, xfrm_msg,
668                                   complete_rewrite);
669 }
670
671 void diff_setup(struct diff_options *options)
672 {
673         memset(options, 0, sizeof(*options));
674         options->output_format = DIFF_FORMAT_RAW;
675         options->line_termination = '\n';
676         options->break_opt = -1;
677         options->rename_limit = -1;
678 }
679
680 int diff_setup_done(struct diff_options *options)
681 {
682         if ((options->find_copies_harder || 0 <= options->rename_limit) &&
683             options->detect_rename != DIFF_DETECT_COPY)
684                 return -1;
685         if (options->setup & DIFF_SETUP_USE_CACHE) {
686                 if (!active_cache)
687                         /* read-cache does not die even when it fails
688                          * so it is safe for us to do this here.  Also
689                          * it does not smudge active_cache or active_nr
690                          * when it fails, so we do not have to worry about
691                          * cleaning it up oufselves either.
692                          */
693                         read_cache();
694         }
695         if (options->setup & DIFF_SETUP_USE_SIZE_CACHE)
696                 use_size_cache = 1;
697
698         return 0;
699 }
700
701 int diff_opt_parse(struct diff_options *options, const char **av, int ac)
702 {
703         const char *arg = av[0];
704         if (!strcmp(arg, "-p") || !strcmp(arg, "-u"))
705                 options->output_format = DIFF_FORMAT_PATCH;
706         else if (!strcmp(arg, "-z"))
707                 options->line_termination = 0;
708         else if (!strncmp(arg, "-l", 2))
709                 options->rename_limit = strtoul(arg+2, NULL, 10);
710         else if (!strcmp(arg, "--name-only"))
711                 options->output_format = DIFF_FORMAT_NAME;
712         else if (!strcmp(arg, "--name-status"))
713                 options->output_format = DIFF_FORMAT_NAME_STATUS;
714         else if (!strcmp(arg, "-R"))
715                 options->reverse_diff = 1;
716         else if (!strncmp(arg, "-S", 2))
717                 options->pickaxe = arg + 2;
718         else if (!strcmp(arg, "-s"))
719                 options->output_format = DIFF_FORMAT_NO_OUTPUT;
720         else if (!strncmp(arg, "-O", 2))
721                 options->orderfile = arg + 2;
722         else if (!strncmp(arg, "--diff-filter=", 14))
723                 options->filter = arg + 14;
724         else if (!strcmp(arg, "--pickaxe-all"))
725                 options->pickaxe_opts = DIFF_PICKAXE_ALL;
726         else if (!strncmp(arg, "-B", 2)) {
727                 if ((options->break_opt =
728                      diff_scoreopt_parse(arg)) == -1)
729                         return -1;
730         }
731         else if (!strncmp(arg, "-M", 2)) {
732                 if ((options->rename_score =
733                      diff_scoreopt_parse(arg)) == -1)
734                         return -1;
735                 options->detect_rename = DIFF_DETECT_RENAME;
736         }
737         else if (!strncmp(arg, "-C", 2)) {
738                 if ((options->rename_score =
739                      diff_scoreopt_parse(arg)) == -1)
740                         return -1;
741                 options->detect_rename = DIFF_DETECT_COPY;
742         }
743         else if (!strcmp(arg, "--find-copies-harder"))
744                 options->find_copies_harder = 1;
745         else
746                 return 0;
747         return 1;
748 }
749
750 static int parse_num(const char **cp_p)
751 {
752         int num, scale, ch, cnt;
753         const char *cp = *cp_p;
754
755         cnt = num = 0;
756         scale = 1;
757         while ('0' <= (ch = *cp) && ch <= '9') {
758                 if (cnt++ < 5) {
759                         /* We simply ignore more than 5 digits precision. */
760                         scale *= 10;
761                         num = num * 10 + ch - '0';
762                 }
763                 cp++;
764         }
765         *cp_p = cp;
766
767         /* user says num divided by scale and we say internally that
768          * is MAX_SCORE * num / scale.
769          */
770         return (MAX_SCORE * num / scale);
771 }
772
773 int diff_scoreopt_parse(const char *opt)
774 {
775         int opt1, opt2, cmd;
776
777         if (*opt++ != '-')
778                 return -1;
779         cmd = *opt++;
780         if (cmd != 'M' && cmd != 'C' && cmd != 'B')
781                 return -1; /* that is not a -M, -C nor -B option */
782
783         opt1 = parse_num(&opt);
784         if (cmd != 'B')
785                 opt2 = 0;
786         else {
787                 if (*opt == 0)
788                         opt2 = 0;
789                 else if (*opt != '/')
790                         return -1; /* we expect -B80/99 or -B80 */
791                 else {
792                         opt++;
793                         opt2 = parse_num(&opt);
794                 }
795         }
796         if (*opt != 0)
797                 return -1;
798         return opt1 | (opt2 << 16);
799 }
800
801 struct diff_queue_struct diff_queued_diff;
802
803 void diff_q(struct diff_queue_struct *queue, struct diff_filepair *dp)
804 {
805         if (queue->alloc <= queue->nr) {
806                 queue->alloc = alloc_nr(queue->alloc);
807                 queue->queue = xrealloc(queue->queue,
808                                         sizeof(dp) * queue->alloc);
809         }
810         queue->queue[queue->nr++] = dp;
811 }
812
813 struct diff_filepair *diff_queue(struct diff_queue_struct *queue,
814                                  struct diff_filespec *one,
815                                  struct diff_filespec *two)
816 {
817         struct diff_filepair *dp = xmalloc(sizeof(*dp));
818         dp->one = one;
819         dp->two = two;
820         dp->score = 0;
821         dp->status = 0;
822         dp->source_stays = 0;
823         dp->broken_pair = 0;
824         if (queue)
825                 diff_q(queue, dp);
826         return dp;
827 }
828
829 void diff_free_filepair(struct diff_filepair *p)
830 {
831         diff_free_filespec_data(p->one);
832         diff_free_filespec_data(p->two);
833         free(p->one);
834         free(p->two);
835         free(p);
836 }
837
838 static void diff_flush_raw(struct diff_filepair *p,
839                            int line_termination,
840                            int inter_name_termination,
841                            int output_format)
842 {
843         int two_paths;
844         char status[10];
845
846         if (line_termination) {
847                 const char *const err =
848                         "path %s cannot be expressed without -z";
849                 if (strchr(p->one->path, line_termination) ||
850                     strchr(p->one->path, inter_name_termination))
851                         die(err, p->one->path);
852                 if (strchr(p->two->path, line_termination) ||
853                     strchr(p->two->path, inter_name_termination))
854                         die(err, p->two->path);
855         }
856
857         if (p->score)
858                 sprintf(status, "%c%03d", p->status,
859                         (int)(0.5 + p->score * 100.0/MAX_SCORE));
860         else {
861                 status[0] = p->status;
862                 status[1] = 0;
863         }
864         switch (p->status) {
865         case DIFF_STATUS_COPIED:
866         case DIFF_STATUS_RENAMED:
867                 two_paths = 1;
868                 break;
869         case DIFF_STATUS_ADDED:
870         case DIFF_STATUS_DELETED:
871                 two_paths = 0;
872                 break;
873         default:
874                 two_paths = 0;
875                 break;
876         }
877         if (output_format != DIFF_FORMAT_NAME_STATUS) {
878                 printf(":%06o %06o %s ",
879                        p->one->mode, p->two->mode, sha1_to_hex(p->one->sha1));
880                 printf("%s ", sha1_to_hex(p->two->sha1));
881         }
882         printf("%s%c%s",status, inter_name_termination, p->one->path);
883         if (two_paths)
884                 printf("%c%s", inter_name_termination, p->two->path);
885         putchar(line_termination);
886 }
887
888 static void diff_flush_name(struct diff_filepair *p,
889                             int line_termination)
890 {
891         printf("%s%c", p->two->path, line_termination);
892 }
893
894 int diff_unmodified_pair(struct diff_filepair *p)
895 {
896         /* This function is written stricter than necessary to support
897          * the currently implemented transformers, but the idea is to
898          * let transformers to produce diff_filepairs any way they want,
899          * and filter and clean them up here before producing the output.
900          */
901         struct diff_filespec *one, *two;
902
903         if (DIFF_PAIR_UNMERGED(p))
904                 return 0; /* unmerged is interesting */
905
906         one = p->one;
907         two = p->two;
908
909         /* deletion, addition, mode or type change
910          * and rename are all interesting.
911          */
912         if (DIFF_FILE_VALID(one) != DIFF_FILE_VALID(two) ||
913             DIFF_PAIR_MODE_CHANGED(p) ||
914             strcmp(one->path, two->path))
915                 return 0;
916
917         /* both are valid and point at the same path.  that is, we are
918          * dealing with a change.
919          */
920         if (one->sha1_valid && two->sha1_valid &&
921             !memcmp(one->sha1, two->sha1, sizeof(one->sha1)))
922                 return 1; /* no change */
923         if (!one->sha1_valid && !two->sha1_valid)
924                 return 1; /* both look at the same file on the filesystem. */
925         return 0;
926 }
927
928 static void diff_flush_patch(struct diff_filepair *p)
929 {
930         if (diff_unmodified_pair(p))
931                 return;
932
933         if ((DIFF_FILE_VALID(p->one) && S_ISDIR(p->one->mode)) ||
934             (DIFF_FILE_VALID(p->two) && S_ISDIR(p->two->mode)))
935                 return; /* no tree diffs in patch format */ 
936
937         run_diff(p);
938 }
939
940 int diff_queue_is_empty(void)
941 {
942         struct diff_queue_struct *q = &diff_queued_diff;
943         int i;
944         for (i = 0; i < q->nr; i++)
945                 if (!diff_unmodified_pair(q->queue[i]))
946                         return 0;
947         return 1;
948 }
949
950 #if DIFF_DEBUG
951 void diff_debug_filespec(struct diff_filespec *s, int x, const char *one)
952 {
953         fprintf(stderr, "queue[%d] %s (%s) %s %06o %s\n",
954                 x, one ? one : "",
955                 s->path,
956                 DIFF_FILE_VALID(s) ? "valid" : "invalid",
957                 s->mode,
958                 s->sha1_valid ? sha1_to_hex(s->sha1) : "");
959         fprintf(stderr, "queue[%d] %s size %lu flags %d\n",
960                 x, one ? one : "",
961                 s->size, s->xfrm_flags);
962 }
963
964 void diff_debug_filepair(const struct diff_filepair *p, int i)
965 {
966         diff_debug_filespec(p->one, i, "one");
967         diff_debug_filespec(p->two, i, "two");
968         fprintf(stderr, "score %d, status %c stays %d broken %d\n",
969                 p->score, p->status ? p->status : '?',
970                 p->source_stays, p->broken_pair);
971 }
972
973 void diff_debug_queue(const char *msg, struct diff_queue_struct *q)
974 {
975         int i;
976         if (msg)
977                 fprintf(stderr, "%s\n", msg);
978         fprintf(stderr, "q->nr = %d\n", q->nr);
979         for (i = 0; i < q->nr; i++) {
980                 struct diff_filepair *p = q->queue[i];
981                 diff_debug_filepair(p, i);
982         }
983 }
984 #endif
985
986 static void diff_resolve_rename_copy(void)
987 {
988         int i, j;
989         struct diff_filepair *p, *pp;
990         struct diff_queue_struct *q = &diff_queued_diff;
991
992         diff_debug_queue("resolve-rename-copy", q);
993
994         for (i = 0; i < q->nr; i++) {
995                 p = q->queue[i];
996                 p->status = 0; /* undecided */
997                 if (DIFF_PAIR_UNMERGED(p))
998                         p->status = DIFF_STATUS_UNMERGED;
999                 else if (!DIFF_FILE_VALID(p->one))
1000                         p->status = DIFF_STATUS_ADDED;
1001                 else if (!DIFF_FILE_VALID(p->two))
1002                         p->status = DIFF_STATUS_DELETED;
1003                 else if (DIFF_PAIR_TYPE_CHANGED(p))
1004                         p->status = DIFF_STATUS_TYPE_CHANGED;
1005
1006                 /* from this point on, we are dealing with a pair
1007                  * whose both sides are valid and of the same type, i.e.
1008                  * either in-place edit or rename/copy edit.
1009                  */
1010                 else if (DIFF_PAIR_RENAME(p)) {
1011                         if (p->source_stays) {
1012                                 p->status = DIFF_STATUS_COPIED;
1013                                 continue;
1014                         }
1015                         /* See if there is some other filepair that
1016                          * copies from the same source as us.  If so
1017                          * we are a copy.  Otherwise we are either a
1018                          * copy if the path stays, or a rename if it
1019                          * does not, but we already handled "stays" case.
1020                          */
1021                         for (j = i + 1; j < q->nr; j++) {
1022                                 pp = q->queue[j];
1023                                 if (strcmp(pp->one->path, p->one->path))
1024                                         continue; /* not us */
1025                                 if (!DIFF_PAIR_RENAME(pp))
1026                                         continue; /* not a rename/copy */
1027                                 /* pp is a rename/copy from the same source */
1028                                 p->status = DIFF_STATUS_COPIED;
1029                                 break;
1030                         }
1031                         if (!p->status)
1032                                 p->status = DIFF_STATUS_RENAMED;
1033                 }
1034                 else if (memcmp(p->one->sha1, p->two->sha1, 20) ||
1035                          p->one->mode != p->two->mode)
1036                         p->status = DIFF_STATUS_MODIFIED;
1037                 else {
1038                         /* This is a "no-change" entry and should not
1039                          * happen anymore, but prepare for broken callers.
1040                          */
1041                         error("feeding unmodified %s to diffcore",
1042                               p->one->path);
1043                         p->status = DIFF_STATUS_UNKNOWN;
1044                 }
1045         }
1046         diff_debug_queue("resolve-rename-copy done", q);
1047 }
1048
1049 void diff_flush(struct diff_options *options)
1050 {
1051         struct diff_queue_struct *q = &diff_queued_diff;
1052         int i;
1053         int inter_name_termination = '\t';
1054         int diff_output_format = options->output_format;
1055         int line_termination = options->line_termination;
1056
1057         if (!line_termination)
1058                 inter_name_termination = 0;
1059
1060         for (i = 0; i < q->nr; i++) {
1061                 struct diff_filepair *p = q->queue[i];
1062                 if ((diff_output_format == DIFF_FORMAT_NO_OUTPUT) ||
1063                     (p->status == DIFF_STATUS_UNKNOWN))
1064                         continue;
1065                 if (p->status == 0)
1066                         die("internal error in diff-resolve-rename-copy");
1067                 switch (diff_output_format) {
1068                 case DIFF_FORMAT_PATCH:
1069                         diff_flush_patch(p);
1070                         break;
1071                 case DIFF_FORMAT_RAW:
1072                 case DIFF_FORMAT_NAME_STATUS:
1073                         diff_flush_raw(p, line_termination,
1074                                        inter_name_termination,
1075                                        diff_output_format);
1076                         break;
1077                 case DIFF_FORMAT_NAME:
1078                         diff_flush_name(p, line_termination);
1079                         break;
1080                 }
1081                 diff_free_filepair(q->queue[i]);
1082         }
1083         free(q->queue);
1084         q->queue = NULL;
1085         q->nr = q->alloc = 0;
1086 }
1087
1088 static void diffcore_apply_filter(const char *filter)
1089 {
1090         int i;
1091         struct diff_queue_struct *q = &diff_queued_diff;
1092         struct diff_queue_struct outq;
1093         outq.queue = NULL;
1094         outq.nr = outq.alloc = 0;
1095
1096         if (!filter)
1097                 return;
1098
1099         if (strchr(filter, DIFF_STATUS_FILTER_AON)) {
1100                 int found;
1101                 for (i = found = 0; !found && i < q->nr; i++) {
1102                         struct diff_filepair *p = q->queue[i];
1103                         if (((p->status == DIFF_STATUS_MODIFIED) &&
1104                              ((p->score &&
1105                                strchr(filter, DIFF_STATUS_FILTER_BROKEN)) ||
1106                               (!p->score &&
1107                                strchr(filter, DIFF_STATUS_MODIFIED)))) ||
1108                             ((p->status != DIFF_STATUS_MODIFIED) &&
1109                              strchr(filter, p->status)))
1110                                 found++;
1111                 }
1112                 if (found)
1113                         return;
1114
1115                 /* otherwise we will clear the whole queue
1116                  * by copying the empty outq at the end of this
1117                  * function, but first clear the current entries
1118                  * in the queue.
1119                  */
1120                 for (i = 0; i < q->nr; i++)
1121                         diff_free_filepair(q->queue[i]);
1122         }
1123         else {
1124                 /* Only the matching ones */
1125                 for (i = 0; i < q->nr; i++) {
1126                         struct diff_filepair *p = q->queue[i];
1127
1128                         if (((p->status == DIFF_STATUS_MODIFIED) &&
1129                              ((p->score &&
1130                                strchr(filter, DIFF_STATUS_FILTER_BROKEN)) ||
1131                               (!p->score &&
1132                                strchr(filter, DIFF_STATUS_MODIFIED)))) ||
1133                             ((p->status != DIFF_STATUS_MODIFIED) &&
1134                              strchr(filter, p->status)))
1135                                 diff_q(&outq, p);
1136                         else
1137                                 diff_free_filepair(p);
1138                 }
1139         }
1140         free(q->queue);
1141         *q = outq;
1142 }
1143
1144 void diffcore_std(struct diff_options *options)
1145 {
1146         if (options->paths && options->paths[0])
1147                 diffcore_pathspec(options->paths);
1148         if (options->break_opt != -1)
1149                 diffcore_break(options->break_opt);
1150         if (options->detect_rename)
1151                 diffcore_rename(options);
1152         if (options->break_opt != -1)
1153                 diffcore_merge_broken();
1154         if (options->pickaxe)
1155                 diffcore_pickaxe(options->pickaxe, options->pickaxe_opts);
1156         if (options->orderfile)
1157                 diffcore_order(options->orderfile);
1158         diff_resolve_rename_copy();
1159         diffcore_apply_filter(options->filter);
1160 }
1161
1162
1163 void diffcore_std_no_resolve(struct diff_options *options)
1164 {
1165         if (options->pickaxe)
1166                 diffcore_pickaxe(options->pickaxe, options->pickaxe_opts);
1167         if (options->orderfile)
1168                 diffcore_order(options->orderfile);
1169         diffcore_apply_filter(options->filter);
1170 }
1171
1172 void diff_addremove(struct diff_options *options,
1173                     int addremove, unsigned mode,
1174                     const unsigned char *sha1,
1175                     const char *base, const char *path)
1176 {
1177         char concatpath[PATH_MAX];
1178         struct diff_filespec *one, *two;
1179
1180         /* This may look odd, but it is a preparation for
1181          * feeding "there are unchanged files which should
1182          * not produce diffs, but when you are doing copy
1183          * detection you would need them, so here they are"
1184          * entries to the diff-core.  They will be prefixed
1185          * with something like '=' or '*' (I haven't decided
1186          * which but should not make any difference).
1187          * Feeding the same new and old to diff_change() 
1188          * also has the same effect.
1189          * Before the final output happens, they are pruned after
1190          * merged into rename/copy pairs as appropriate.
1191          */
1192         if (options->reverse_diff)
1193                 addremove = (addremove == '+' ? '-' :
1194                              addremove == '-' ? '+' : addremove);
1195
1196         if (!path) path = "";
1197         sprintf(concatpath, "%s%s", base, path);
1198         one = alloc_filespec(concatpath);
1199         two = alloc_filespec(concatpath);
1200
1201         if (addremove != '+')
1202                 fill_filespec(one, sha1, mode);
1203         if (addremove != '-')
1204                 fill_filespec(two, sha1, mode);
1205
1206         diff_queue(&diff_queued_diff, one, two);
1207 }
1208
1209 void diff_change(struct diff_options *options,
1210                  unsigned old_mode, unsigned new_mode,
1211                  const unsigned char *old_sha1,
1212                  const unsigned char *new_sha1,
1213                  const char *base, const char *path) 
1214 {
1215         char concatpath[PATH_MAX];
1216         struct diff_filespec *one, *two;
1217
1218         if (options->reverse_diff) {
1219                 unsigned tmp;
1220                 const unsigned char *tmp_c;
1221                 tmp = old_mode; old_mode = new_mode; new_mode = tmp;
1222                 tmp_c = old_sha1; old_sha1 = new_sha1; new_sha1 = tmp_c;
1223         }
1224         if (!path) path = "";
1225         sprintf(concatpath, "%s%s", base, path);
1226         one = alloc_filespec(concatpath);
1227         two = alloc_filespec(concatpath);
1228         fill_filespec(one, old_sha1, old_mode);
1229         fill_filespec(two, new_sha1, new_mode);
1230
1231         diff_queue(&diff_queued_diff, one, two);
1232 }
1233
1234 void diff_unmerge(struct diff_options *options,
1235                   const char *path)
1236 {
1237         struct diff_filespec *one, *two;
1238         one = alloc_filespec(path);
1239         two = alloc_filespec(path);
1240         diff_queue(&diff_queued_diff, one, two);
1241 }