Add Pine 4.63 help from Daniel.
[git.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 reverse_diff;
16 static int use_size_cache;
17
18 static const char *external_diff(void)
19 {
20         static const char *external_diff_cmd = NULL;
21         static int done_preparing = 0;
22         const char *env_diff_opts;
23
24         if (done_preparing)
25                 return external_diff_cmd;
26
27         /*
28          * Default values above are meant to match the
29          * Linux kernel development style.  Examples of
30          * alternative styles you can specify via environment
31          * variables are:
32          *
33          * GIT_DIFF_OPTS="-c";
34          */
35         external_diff_cmd = gitenv("GIT_EXTERNAL_DIFF");
36
37         /* In case external diff fails... */
38         env_diff_opts = gitenv("GIT_DIFF_OPTS");
39         if (env_diff_opts) diff_opts = env_diff_opts;
40
41         done_preparing = 1;
42         return external_diff_cmd;
43 }
44
45 #define TEMPFILE_PATH_LEN               50
46
47 static struct diff_tempfile {
48         const char *name; /* filename external diff should read from */
49         char hex[41];
50         char mode[10];
51         char tmp_path[TEMPFILE_PATH_LEN];
52 } diff_temp[2];
53
54 static int count_lines(const char *filename)
55 {
56         FILE *in;
57         int count, ch, completely_empty = 1, nl_just_seen = 0;
58         in = fopen(filename, "r");
59         count = 0;
60         while ((ch = fgetc(in)) != EOF)
61                 if (ch == '\n') {
62                         count++;
63                         nl_just_seen = 1;
64                         completely_empty = 0;
65                 }
66                 else {
67                         nl_just_seen = 0;
68                         completely_empty = 0;
69                 }
70         fclose(in);
71         if (completely_empty)
72                 return 0;
73         if (!nl_just_seen)
74                 count++; /* no trailing newline */
75         return count;
76 }
77
78 static void print_line_count(int count)
79 {
80         switch (count) {
81         case 0:
82                 printf("0,0");
83                 break;
84         case 1:
85                 printf("1");
86                 break;
87         default:
88                 printf("1,%d", count);
89                 break;
90         }
91 }
92
93 static void copy_file(int prefix, const char *filename)
94 {
95         FILE *in;
96         int ch, nl_just_seen = 1;
97         in = fopen(filename, "r");
98         while ((ch = fgetc(in)) != EOF) {
99                 if (nl_just_seen)
100                         putchar(prefix);
101                 putchar(ch);
102                 if (ch == '\n')
103                         nl_just_seen = 1;
104                 else
105                         nl_just_seen = 0;
106         }
107         fclose(in);
108         if (!nl_just_seen)
109                 printf("\n\\ No newline at end of file\n");
110 }
111
112 static void emit_rewrite_diff(const char *name_a,
113                               const char *name_b,
114                               struct diff_tempfile *temp)
115 {
116         /* Use temp[i].name as input, name_a and name_b as labels */
117         int lc_a, lc_b;
118         lc_a = count_lines(temp[0].name);
119         lc_b = count_lines(temp[1].name);
120         printf("--- %s\n+++ %s\n@@ -", name_a, name_b);
121         print_line_count(lc_a);
122         printf(" +");
123         print_line_count(lc_b);
124         printf(" @@\n");
125         if (lc_a)
126                 copy_file('-', temp[0].name);
127         if (lc_b)
128                 copy_file('+', temp[1].name);
129 }
130
131 static void builtin_diff(const char *name_a,
132                          const char *name_b,
133                          struct diff_tempfile *temp,
134                          const char *xfrm_msg,
135                          int complete_rewrite)
136 {
137         int i, next_at, cmd_size;
138         const char *const diff_cmd = "diff -L%s%s -L%s%s";
139         const char *const diff_arg  = "%s %s||:"; /* "||:" is to return 0 */
140         const char *input_name_sq[2];
141         const char *path0[2];
142         const char *path1[2];
143         const char *name_sq[2];
144         char *cmd;
145
146         name_sq[0] = sq_quote(name_a);
147         name_sq[1] = sq_quote(name_b);
148
149         /* diff_cmd and diff_arg have 6 %s in total which makes
150          * the sum of these strings 12 bytes larger than required.
151          * we use 2 spaces around diff-opts, and we need to count
152          * terminating NUL, so we subtract 9 here.
153          */
154         cmd_size = (strlen(diff_cmd) + strlen(diff_opts) +
155                         strlen(diff_arg) - 9);
156         for (i = 0; i < 2; i++) {
157                 input_name_sq[i] = sq_quote(temp[i].name);
158                 if (!strcmp(temp[i].name, "/dev/null")) {
159                         path0[i] = "/dev/null";
160                         path1[i] = "";
161                 } else {
162                         path0[i] = i ? "b/" : "a/";
163                         path1[i] = name_sq[i];
164                 }
165                 cmd_size += (strlen(path0[i]) + strlen(path1[i]) +
166                              strlen(input_name_sq[i]));
167         }
168
169         cmd = xmalloc(cmd_size);
170
171         next_at = 0;
172         next_at += snprintf(cmd+next_at, cmd_size-next_at,
173                             diff_cmd,
174                             path0[0], path1[0], path0[1], path1[1]);
175         next_at += snprintf(cmd+next_at, cmd_size-next_at,
176                             " %s ", diff_opts);
177         next_at += snprintf(cmd+next_at, cmd_size-next_at,
178                             diff_arg, input_name_sq[0], input_name_sq[1]);
179
180         printf("diff --git a/%s b/%s\n", name_a, name_b);
181         if (!path1[0][0]) {
182                 printf("new file mode %s\n", temp[1].mode);
183                 if (xfrm_msg && xfrm_msg[0])
184                         puts(xfrm_msg);
185         }
186         else if (!path1[1][0]) {
187                 printf("deleted file mode %s\n", temp[0].mode);
188                 if (xfrm_msg && xfrm_msg[0])
189                         puts(xfrm_msg);
190         }
191         else {
192                 if (strcmp(temp[0].mode, temp[1].mode)) {
193                         printf("old mode %s\n", temp[0].mode);
194                         printf("new mode %s\n", temp[1].mode);
195                 }
196                 if (xfrm_msg && xfrm_msg[0])
197                         puts(xfrm_msg);
198                 if (strncmp(temp[0].mode, temp[1].mode, 3))
199                         /* we do not run diff between different kind
200                          * of objects.
201                          */
202                         exit(0);
203                 if (complete_rewrite) {
204                         fflush(NULL);
205                         emit_rewrite_diff(name_a, name_b, temp);
206                         exit(0);
207                 }
208         }
209         fflush(NULL);
210         execlp("/bin/sh","sh", "-c", cmd, NULL);
211 }
212
213 struct diff_filespec *alloc_filespec(const char *path)
214 {
215         int namelen = strlen(path);
216         struct diff_filespec *spec = xmalloc(sizeof(*spec) + namelen + 1);
217         spec->path = (char *)(spec + 1);
218         strcpy(spec->path, path);
219         spec->should_free = spec->should_munmap = 0;
220         spec->xfrm_flags = 0;
221         spec->size = 0;
222         spec->data = NULL;
223         spec->mode = 0;
224         memset(spec->sha1, 0, 20);
225         return spec;
226 }
227
228 void fill_filespec(struct diff_filespec *spec, const unsigned char *sha1,
229                    unsigned short mode)
230 {
231         if (mode) {
232                 spec->mode = DIFF_FILE_CANON_MODE(mode);
233                 memcpy(spec->sha1, sha1, 20);
234                 spec->sha1_valid = !!memcmp(sha1, null_sha1, 20);
235         }
236 }
237
238 /*
239  * Given a name and sha1 pair, if the dircache tells us the file in
240  * the work tree has that object contents, return true, so that
241  * prepare_temp_file() does not have to inflate and extract.
242  */
243 static int work_tree_matches(const char *name, const unsigned char *sha1)
244 {
245         struct cache_entry *ce;
246         struct stat st;
247         int pos, len;
248
249         /* We do not read the cache ourselves here, because the
250          * benchmark with my previous version that always reads cache
251          * shows that it makes things worse for diff-tree comparing
252          * two linux-2.6 kernel trees in an already checked out work
253          * tree.  This is because most diff-tree comparisons deal with
254          * only a small number of files, while reading the cache is
255          * expensive for a large project, and its cost outweighs the
256          * savings we get by not inflating the object to a temporary
257          * file.  Practically, this code only helps when we are used
258          * by diff-cache --cached, which does read the cache before
259          * calling us.
260          */
261         if (!active_cache)
262                 return 0;
263
264         len = strlen(name);
265         pos = cache_name_pos(name, len);
266         if (pos < 0)
267                 return 0;
268         ce = active_cache[pos];
269         if ((lstat(name, &st) < 0) ||
270             !S_ISREG(st.st_mode) || /* careful! */
271             ce_match_stat(ce, &st) ||
272             memcmp(sha1, ce->sha1, 20))
273                 return 0;
274         /* we return 1 only when we can stat, it is a regular file,
275          * stat information matches, and sha1 recorded in the cache
276          * matches.  I.e. we know the file in the work tree really is
277          * the same as the <name, sha1> pair.
278          */
279         return 1;
280 }
281
282 static struct sha1_size_cache {
283         unsigned char sha1[20];
284         unsigned long size;
285 } **sha1_size_cache;
286 static int sha1_size_cache_nr, sha1_size_cache_alloc;
287
288 static struct sha1_size_cache *locate_size_cache(unsigned char *sha1,
289                                                  int find_only,
290                                                  unsigned long size)
291 {
292         int first, last;
293         struct sha1_size_cache *e;
294
295         first = 0;
296         last = sha1_size_cache_nr;
297         while (last > first) {
298                 int cmp, next = (last + first) >> 1;
299                 e = sha1_size_cache[next];
300                 cmp = memcmp(e->sha1, sha1, 20);
301                 if (!cmp)
302                         return e;
303                 if (cmp < 0) {
304                         last = next;
305                         continue;
306                 }
307                 first = next+1;
308         }
309         /* not found */
310         if (find_only)
311                 return NULL;
312         /* insert to make it at "first" */
313         if (sha1_size_cache_alloc <= sha1_size_cache_nr) {
314                 sha1_size_cache_alloc = alloc_nr(sha1_size_cache_alloc);
315                 sha1_size_cache = xrealloc(sha1_size_cache,
316                                            sha1_size_cache_alloc *
317                                            sizeof(*sha1_size_cache));
318         }
319         sha1_size_cache_nr++;
320         if (first < sha1_size_cache_nr)
321                 memmove(sha1_size_cache + first + 1, sha1_size_cache + first,
322                         (sha1_size_cache_nr - first - 1) *
323                         sizeof(*sha1_size_cache));
324         e = xmalloc(sizeof(struct sha1_size_cache));
325         sha1_size_cache[first] = e;
326         memcpy(e->sha1, sha1, 20);
327         e->size = size;
328         return e;
329 }
330
331 /*
332  * While doing rename detection and pickaxe operation, we may need to
333  * grab the data for the blob (or file) for our own in-core comparison.
334  * diff_filespec has data and size fields for this purpose.
335  */
336 int diff_populate_filespec(struct diff_filespec *s, int size_only)
337 {
338         int err = 0;
339         if (!DIFF_FILE_VALID(s))
340                 die("internal error: asking to populate invalid file.");
341         if (S_ISDIR(s->mode))
342                 return -1;
343
344         if (!use_size_cache)
345                 size_only = 0;
346
347         if (s->data)
348                 return err;
349         if (!s->sha1_valid ||
350             work_tree_matches(s->path, s->sha1)) {
351                 struct stat st;
352                 int fd;
353                 if (lstat(s->path, &st) < 0) {
354                         if (errno == ENOENT) {
355                         err_empty:
356                                 err = -1;
357                         empty:
358                                 s->data = "";
359                                 s->size = 0;
360                                 return err;
361                         }
362                 }
363                 s->size = st.st_size;
364                 if (!s->size)
365                         goto empty;
366                 if (size_only)
367                         return 0;
368                 if (S_ISLNK(st.st_mode)) {
369                         int ret;
370                         s->data = xmalloc(s->size);
371                         s->should_free = 1;
372                         ret = readlink(s->path, s->data, s->size);
373                         if (ret < 0) {
374                                 free(s->data);
375                                 goto err_empty;
376                         }
377                         return 0;
378                 }
379                 fd = open(s->path, O_RDONLY);
380                 if (fd < 0)
381                         goto err_empty;
382                 s->data = mmap(NULL, s->size, PROT_READ, MAP_PRIVATE, fd, 0);
383                 close(fd);
384                 if (s->data == MAP_FAILED)
385                         goto err_empty;
386                 s->should_munmap = 1;
387         }
388         else {
389                 char type[20];
390                 struct sha1_size_cache *e;
391
392                 if (size_only) {
393                         e = locate_size_cache(s->sha1, 1, 0);
394                         if (e) {
395                                 s->size = e->size;
396                                 return 0;
397                         }
398                         if (!sha1_object_info(s->sha1, type, &s->size))
399                                 locate_size_cache(s->sha1, 0, s->size);
400                 }
401                 else {
402                         s->data = read_sha1_file(s->sha1, type, &s->size);
403                         s->should_free = 1;
404                 }
405         }
406         return 0;
407 }
408
409 void diff_free_filespec(struct diff_filespec *s)
410 {
411         if (s->should_free)
412                 free(s->data);
413         else if (s->should_munmap)
414                 munmap(s->data, s->size);
415         free(s);
416 }
417
418 static void prep_temp_blob(struct diff_tempfile *temp,
419                            void *blob,
420                            unsigned long size,
421                            unsigned char *sha1,
422                            int mode)
423 {
424         int fd;
425
426         fd = git_mkstemp(temp->tmp_path, TEMPFILE_PATH_LEN, ".diff_XXXXXX");
427         if (fd < 0)
428                 die("unable to create temp-file");
429         if (write(fd, blob, size) != size)
430                 die("unable to write temp-file");
431         close(fd);
432         temp->name = temp->tmp_path;
433         strcpy(temp->hex, sha1_to_hex(sha1));
434         temp->hex[40] = 0;
435         sprintf(temp->mode, "%06o", mode);
436 }
437
438 static void prepare_temp_file(const char *name,
439                               struct diff_tempfile *temp,
440                               struct diff_filespec *one)
441 {
442         if (!DIFF_FILE_VALID(one)) {
443         not_a_valid_file:
444                 /* A '-' entry produces this for file-2, and
445                  * a '+' entry produces this for file-1.
446                  */
447                 temp->name = "/dev/null";
448                 strcpy(temp->hex, ".");
449                 strcpy(temp->mode, ".");
450                 return;
451         }
452
453         if (!one->sha1_valid ||
454             work_tree_matches(name, one->sha1)) {
455                 struct stat st;
456                 if (lstat(name, &st) < 0) {
457                         if (errno == ENOENT)
458                                 goto not_a_valid_file;
459                         die("stat(%s): %s", name, strerror(errno));
460                 }
461                 if (S_ISLNK(st.st_mode)) {
462                         int ret;
463                         char *buf, buf_[1024];
464                         buf = ((sizeof(buf_) < st.st_size) ?
465                                xmalloc(st.st_size) : buf_);
466                         ret = readlink(name, buf, st.st_size);
467                         if (ret < 0)
468                                 die("readlink(%s)", name);
469                         prep_temp_blob(temp, buf, st.st_size,
470                                        (one->sha1_valid ?
471                                         one->sha1 : null_sha1),
472                                        (one->sha1_valid ?
473                                         one->mode : S_IFLNK));
474                 }
475                 else {
476                         /* we can borrow from the file in the work tree */
477                         temp->name = name;
478                         if (!one->sha1_valid)
479                                 strcpy(temp->hex, sha1_to_hex(null_sha1));
480                         else
481                                 strcpy(temp->hex, sha1_to_hex(one->sha1));
482                         /* Even though we may sometimes borrow the
483                          * contents from the work tree, we always want
484                          * one->mode.  mode is trustworthy even when
485                          * !(one->sha1_valid), as long as
486                          * DIFF_FILE_VALID(one).
487                          */
488                         sprintf(temp->mode, "%06o", one->mode);
489                 }
490                 return;
491         }
492         else {
493                 if (diff_populate_filespec(one, 0))
494                         die("cannot read data blob for %s", one->path);
495                 prep_temp_blob(temp, one->data, one->size,
496                                one->sha1, one->mode);
497         }
498 }
499
500 static void remove_tempfile(void)
501 {
502         int i;
503
504         for (i = 0; i < 2; i++)
505                 if (diff_temp[i].name == diff_temp[i].tmp_path) {
506                         unlink(diff_temp[i].name);
507                         diff_temp[i].name = NULL;
508                 }
509 }
510
511 static void remove_tempfile_on_signal(int signo)
512 {
513         remove_tempfile();
514 }
515
516 /* An external diff command takes:
517  *
518  * diff-cmd name infile1 infile1-sha1 infile1-mode \
519  *               infile2 infile2-sha1 infile2-mode [ rename-to ]
520  *
521  */
522 static void run_external_diff(const char *pgm,
523                               const char *name,
524                               const char *other,
525                               struct diff_filespec *one,
526                               struct diff_filespec *two,
527                               const char *xfrm_msg,
528                               int complete_rewrite)
529 {
530         struct diff_tempfile *temp = diff_temp;
531         pid_t pid;
532         int status;
533         static int atexit_asked = 0;
534         const char *othername;
535
536         othername = (other? other : name);
537         if (one && two) {
538                 prepare_temp_file(name, &temp[0], one);
539                 prepare_temp_file(othername, &temp[1], two);
540                 if (! atexit_asked &&
541                     (temp[0].name == temp[0].tmp_path ||
542                      temp[1].name == temp[1].tmp_path)) {
543                         atexit_asked = 1;
544                         atexit(remove_tempfile);
545                 }
546                 signal(SIGINT, remove_tempfile_on_signal);
547         }
548
549         fflush(NULL);
550         pid = fork();
551         if (pid < 0)
552                 die("unable to fork");
553         if (!pid) {
554                 if (pgm) {
555                         if (one && two) {
556                                 const char *exec_arg[10];
557                                 const char **arg = &exec_arg[0];
558                                 *arg++ = pgm;
559                                 *arg++ = name;
560                                 *arg++ = temp[0].name;
561                                 *arg++ = temp[0].hex;
562                                 *arg++ = temp[0].mode;
563                                 *arg++ = temp[1].name;
564                                 *arg++ = temp[1].hex;
565                                 *arg++ = temp[1].mode;
566                                 if (other) {
567                                         *arg++ = other;
568                                         *arg++ = xfrm_msg;
569                                 }
570                                 *arg = NULL;
571                                 execvp(pgm, (char *const*) exec_arg);
572                         }
573                         else
574                                 execlp(pgm, pgm, name, NULL);
575                 }
576                 /*
577                  * otherwise we use the built-in one.
578                  */
579                 if (one && two)
580                         builtin_diff(name, othername, temp, xfrm_msg,
581                                      complete_rewrite);
582                 else
583                         printf("* Unmerged path %s\n", name);
584                 exit(0);
585         }
586         if (waitpid(pid, &status, 0) < 0 ||
587             !WIFEXITED(status) || WEXITSTATUS(status)) {
588                 /* Earlier we did not check the exit status because
589                  * diff exits non-zero if files are different, and
590                  * we are not interested in knowing that.  It was a
591                  * mistake which made it harder to quit a diff-*
592                  * session that uses the git-apply-patch-script as
593                  * the GIT_EXTERNAL_DIFF.  A custom GIT_EXTERNAL_DIFF
594                  * should also exit non-zero only when it wants to
595                  * abort the entire diff-* session.
596                  */
597                 remove_tempfile();
598                 fprintf(stderr, "external diff died, stopping at %s.\n", name);
599                 exit(1);
600         }
601         remove_tempfile();
602 }
603
604 static void run_diff(struct diff_filepair *p)
605 {
606         const char *pgm = external_diff();
607         char msg_[PATH_MAX*2+200], *xfrm_msg;
608         struct diff_filespec *one;
609         struct diff_filespec *two;
610         const char *name;
611         const char *other;
612         int complete_rewrite = 0;
613
614         if (DIFF_PAIR_UNMERGED(p)) {
615                 /* unmerged */
616                 run_external_diff(pgm, p->one->path, NULL, NULL, NULL, NULL,
617                                   0);
618                 return;
619         }
620
621         name = p->one->path;
622         other = (strcmp(name, p->two->path) ? p->two->path : NULL);
623         one = p->one; two = p->two;
624         switch (p->status) {
625         case DIFF_STATUS_COPIED:
626                 sprintf(msg_,
627                         "similarity index %d%%\n"
628                         "copy from %s\n"
629                         "copy to %s",
630                         (int)(0.5 + p->score * 100.0/MAX_SCORE),
631                         name, other);
632                 xfrm_msg = msg_;
633                 break;
634         case DIFF_STATUS_RENAMED:
635                 sprintf(msg_,
636                         "similarity index %d%%\n"
637                         "rename from %s\n"
638                         "rename to %s",
639                         (int)(0.5 + p->score * 100.0/MAX_SCORE),
640                         name, other);
641                 xfrm_msg = msg_;
642                 break;
643         case DIFF_STATUS_MODIFIED:
644                 if (p->score) {
645                         sprintf(msg_,
646                                 "dissimilarity index %d%%",
647                                 (int)(0.5 + p->score * 100.0/MAX_SCORE));
648                         xfrm_msg = msg_;
649                         complete_rewrite = 1;
650                         break;
651                 }
652                 /* fallthru */
653         default:
654                 xfrm_msg = NULL;
655         }
656
657         if (!pgm &&
658             DIFF_FILE_VALID(one) && DIFF_FILE_VALID(two) &&
659             (S_IFMT & one->mode) != (S_IFMT & two->mode)) {
660                 /* a filepair that changes between file and symlink
661                  * needs to be split into deletion and creation.
662                  */
663                 struct diff_filespec *null = alloc_filespec(two->path);
664                 run_external_diff(NULL, name, other, one, null, xfrm_msg, 0);
665                 free(null);
666                 null = alloc_filespec(one->path);
667                 run_external_diff(NULL, name, other, null, two, xfrm_msg, 0);
668                 free(null);
669         }
670         else
671                 run_external_diff(pgm, name, other, one, two, xfrm_msg,
672                                   complete_rewrite);
673 }
674
675 void diff_setup(int flags)
676 {
677         if (flags & DIFF_SETUP_REVERSE)
678                 reverse_diff = 1;
679         if (flags & DIFF_SETUP_USE_CACHE) {
680                 if (!active_cache)
681                         /* read-cache does not die even when it fails
682                          * so it is safe for us to do this here.  Also
683                          * it does not smudge active_cache or active_nr
684                          * when it fails, so we do not have to worry about
685                          * cleaning it up oufselves either.
686                          */
687                         read_cache();
688         }
689         if (flags & DIFF_SETUP_USE_SIZE_CACHE)
690                 use_size_cache = 1;
691         
692 }
693
694 static int parse_num(const char **cp_p)
695 {
696         int num, scale, ch, cnt;
697         const char *cp = *cp_p;
698
699         cnt = num = 0;
700         scale = 1;
701         while ('0' <= (ch = *cp) && ch <= '9') {
702                 if (cnt++ < 5) {
703                         /* We simply ignore more than 5 digits precision. */
704                         scale *= 10;
705                         num = num * 10 + ch - '0';
706                 }
707                 cp++;
708         }
709         *cp_p = cp;
710
711         /* user says num divided by scale and we say internally that
712          * is MAX_SCORE * num / scale.
713          */
714         return (MAX_SCORE * num / scale);
715 }
716
717 int diff_scoreopt_parse(const char *opt)
718 {
719         int opt1, opt2, cmd;
720
721         if (*opt++ != '-')
722                 return -1;
723         cmd = *opt++;
724         if (cmd != 'M' && cmd != 'C' && cmd != 'B')
725                 return -1; /* that is not a -M, -C nor -B option */
726
727         opt1 = parse_num(&opt);
728         if (cmd != 'B')
729                 opt2 = 0;
730         else {
731                 if (*opt == 0)
732                         opt2 = 0;
733                 else if (*opt != '/')
734                         return -1; /* we expect -B80/99 or -B80 */
735                 else {
736                         opt++;
737                         opt2 = parse_num(&opt);
738                 }
739         }
740         if (*opt != 0)
741                 return -1;
742         return opt1 | (opt2 << 16);
743 }
744
745 struct diff_queue_struct diff_queued_diff;
746
747 void diff_q(struct diff_queue_struct *queue, struct diff_filepair *dp)
748 {
749         if (queue->alloc <= queue->nr) {
750                 queue->alloc = alloc_nr(queue->alloc);
751                 queue->queue = xrealloc(queue->queue,
752                                         sizeof(dp) * queue->alloc);
753         }
754         queue->queue[queue->nr++] = dp;
755 }
756
757 struct diff_filepair *diff_queue(struct diff_queue_struct *queue,
758                                  struct diff_filespec *one,
759                                  struct diff_filespec *two)
760 {
761         struct diff_filepair *dp = xmalloc(sizeof(*dp));
762         dp->one = one;
763         dp->two = two;
764         dp->score = 0;
765         dp->status = 0;
766         dp->source_stays = 0;
767         dp->broken_pair = 0;
768         diff_q(queue, dp);
769         return dp;
770 }
771
772 void diff_free_filepair(struct diff_filepair *p)
773 {
774         diff_free_filespec(p->one);
775         diff_free_filespec(p->two);
776         free(p);
777 }
778
779 static void diff_flush_raw(struct diff_filepair *p,
780                            int line_termination,
781                            int inter_name_termination)
782 {
783         int two_paths;
784         char status[10];
785
786         if (line_termination) {
787                 const char *const err =
788                         "path %s cannot be expressed without -z";
789                 if (strchr(p->one->path, line_termination) ||
790                     strchr(p->one->path, inter_name_termination))
791                         die(err, p->one->path);
792                 if (strchr(p->two->path, line_termination) ||
793                     strchr(p->two->path, inter_name_termination))
794                         die(err, p->two->path);
795         }
796
797         if (p->score)
798                 sprintf(status, "%c%03d", p->status,
799                         (int)(0.5 + p->score * 100.0/MAX_SCORE));
800         else {
801                 status[0] = p->status;
802                 status[1] = 0;
803         }
804         switch (p->status) {
805         case DIFF_STATUS_COPIED:
806         case DIFF_STATUS_RENAMED:
807                 two_paths = 1;
808                 break;
809         case DIFF_STATUS_ADDED:
810         case DIFF_STATUS_DELETED:
811                 two_paths = 0;
812                 break;
813         default:
814                 two_paths = 0;
815                 break;
816         }
817         printf(":%06o %06o %s ",
818                p->one->mode, p->two->mode, sha1_to_hex(p->one->sha1));
819         printf("%s %s%c%s",
820                sha1_to_hex(p->two->sha1),
821                status,
822                inter_name_termination,
823                p->one->path);
824         if (two_paths)
825                 printf("%c%s", inter_name_termination, p->two->path);
826         putchar(line_termination);
827 }
828
829 static void diff_flush_name(struct diff_filepair *p,
830                             int line_termination)
831 {
832         printf("%s%c", p->two->path, line_termination);
833 }
834
835 int diff_unmodified_pair(struct diff_filepair *p)
836 {
837         /* This function is written stricter than necessary to support
838          * the currently implemented transformers, but the idea is to
839          * let transformers to produce diff_filepairs any way they want,
840          * and filter and clean them up here before producing the output.
841          */
842         struct diff_filespec *one, *two;
843
844         if (DIFF_PAIR_UNMERGED(p))
845                 return 0; /* unmerged is interesting */
846
847         one = p->one;
848         two = p->two;
849
850         /* deletion, addition, mode or type change
851          * and rename are all interesting.
852          */
853         if (DIFF_FILE_VALID(one) != DIFF_FILE_VALID(two) ||
854             DIFF_PAIR_MODE_CHANGED(p) ||
855             strcmp(one->path, two->path))
856                 return 0;
857
858         /* both are valid and point at the same path.  that is, we are
859          * dealing with a change.
860          */
861         if (one->sha1_valid && two->sha1_valid &&
862             !memcmp(one->sha1, two->sha1, sizeof(one->sha1)))
863                 return 1; /* no change */
864         if (!one->sha1_valid && !two->sha1_valid)
865                 return 1; /* both look at the same file on the filesystem. */
866         return 0;
867 }
868
869 static void diff_flush_patch(struct diff_filepair *p)
870 {
871         if (diff_unmodified_pair(p))
872                 return;
873
874         if ((DIFF_FILE_VALID(p->one) && S_ISDIR(p->one->mode)) ||
875             (DIFF_FILE_VALID(p->two) && S_ISDIR(p->two->mode)))
876                 return; /* no tree diffs in patch format */ 
877
878         run_diff(p);
879 }
880
881 int diff_queue_is_empty(void)
882 {
883         struct diff_queue_struct *q = &diff_queued_diff;
884         int i;
885         for (i = 0; i < q->nr; i++)
886                 if (!diff_unmodified_pair(q->queue[i]))
887                         return 0;
888         return 1;
889 }
890
891 #if DIFF_DEBUG
892 void diff_debug_filespec(struct diff_filespec *s, int x, const char *one)
893 {
894         fprintf(stderr, "queue[%d] %s (%s) %s %06o %s\n",
895                 x, one ? one : "",
896                 s->path,
897                 DIFF_FILE_VALID(s) ? "valid" : "invalid",
898                 s->mode,
899                 s->sha1_valid ? sha1_to_hex(s->sha1) : "");
900         fprintf(stderr, "queue[%d] %s size %lu flags %d\n",
901                 x, one ? one : "",
902                 s->size, s->xfrm_flags);
903 }
904
905 void diff_debug_filepair(const struct diff_filepair *p, int i)
906 {
907         diff_debug_filespec(p->one, i, "one");
908         diff_debug_filespec(p->two, i, "two");
909         fprintf(stderr, "score %d, status %c stays %d broken %d\n",
910                 p->score, p->status ? p->status : '?',
911                 p->source_stays, p->broken_pair);
912 }
913
914 void diff_debug_queue(const char *msg, struct diff_queue_struct *q)
915 {
916         int i;
917         if (msg)
918                 fprintf(stderr, "%s\n", msg);
919         fprintf(stderr, "q->nr = %d\n", q->nr);
920         for (i = 0; i < q->nr; i++) {
921                 struct diff_filepair *p = q->queue[i];
922                 diff_debug_filepair(p, i);
923         }
924 }
925 #endif
926
927 static void diff_resolve_rename_copy(void)
928 {
929         int i, j;
930         struct diff_filepair *p, *pp;
931         struct diff_queue_struct *q = &diff_queued_diff;
932
933         diff_debug_queue("resolve-rename-copy", q);
934
935         for (i = 0; i < q->nr; i++) {
936                 p = q->queue[i];
937                 p->status = 0; /* undecided */
938                 if (DIFF_PAIR_UNMERGED(p))
939                         p->status = DIFF_STATUS_UNMERGED;
940                 else if (!DIFF_FILE_VALID(p->one))
941                         p->status = DIFF_STATUS_ADDED;
942                 else if (!DIFF_FILE_VALID(p->two))
943                         p->status = DIFF_STATUS_DELETED;
944                 else if (DIFF_PAIR_TYPE_CHANGED(p))
945                         p->status = DIFF_STATUS_TYPE_CHANGED;
946
947                 /* from this point on, we are dealing with a pair
948                  * whose both sides are valid and of the same type, i.e.
949                  * either in-place edit or rename/copy edit.
950                  */
951                 else if (DIFF_PAIR_RENAME(p)) {
952                         if (p->source_stays) {
953                                 p->status = DIFF_STATUS_COPIED;
954                                 continue;
955                         }
956                         /* See if there is some other filepair that
957                          * copies from the same source as us.  If so
958                          * we are a copy.  Otherwise we are a rename.
959                          */
960                         for (j = i + 1; j < q->nr; j++) {
961                                 pp = q->queue[j];
962                                 if (strcmp(pp->one->path, p->one->path))
963                                         continue; /* not us */
964                                 if (!DIFF_PAIR_RENAME(pp))
965                                         continue; /* not a rename/copy */
966                                 /* pp is a rename/copy from the same source */
967                                 p->status = DIFF_STATUS_COPIED;
968                                 break;
969                         }
970                         if (!p->status)
971                                 p->status = DIFF_STATUS_RENAMED;
972                 }
973                 else if (memcmp(p->one->sha1, p->two->sha1, 20) ||
974                          p->one->mode != p->two->mode)
975                         p->status = DIFF_STATUS_MODIFIED;
976                 else {
977                         /* This is a "no-change" entry and should not
978                          * happen anymore, but prepare for broken callers.
979                          */
980                         error("feeding unmodified %s to diffcore",
981                               p->one->path);
982                         p->status = DIFF_STATUS_UNKNOWN;
983                 }
984         }
985         diff_debug_queue("resolve-rename-copy done", q);
986 }
987
988 void diff_flush(int diff_output_style, int line_termination)
989 {
990         struct diff_queue_struct *q = &diff_queued_diff;
991         int i;
992         int inter_name_termination = '\t';
993
994         if (!line_termination)
995                 inter_name_termination = 0;
996
997         for (i = 0; i < q->nr; i++) {
998                 struct diff_filepair *p = q->queue[i];
999                 if ((diff_output_style == DIFF_FORMAT_NO_OUTPUT) ||
1000                     (p->status == DIFF_STATUS_UNKNOWN))
1001                         continue;
1002                 if (p->status == 0)
1003                         die("internal error in diff-resolve-rename-copy");
1004                 switch (diff_output_style) {
1005                 case DIFF_FORMAT_PATCH:
1006                         diff_flush_patch(p);
1007                         break;
1008                 case DIFF_FORMAT_RAW:
1009                         diff_flush_raw(p, line_termination,
1010                                        inter_name_termination);
1011                         break;
1012                 case DIFF_FORMAT_NAME:
1013                         diff_flush_name(p, line_termination);
1014                         break;
1015                 }
1016                 diff_free_filepair(q->queue[i]);
1017         }
1018         free(q->queue);
1019         q->queue = NULL;
1020         q->nr = q->alloc = 0;
1021 }
1022
1023 static void diffcore_apply_filter(const char *filter)
1024 {
1025         int i;
1026         struct diff_queue_struct *q = &diff_queued_diff;
1027         struct diff_queue_struct outq;
1028         outq.queue = NULL;
1029         outq.nr = outq.alloc = 0;
1030
1031         if (!filter)
1032                 return;
1033
1034         if (strchr(filter, DIFF_STATUS_FILTER_AON)) {
1035                 int found;
1036                 for (i = found = 0; !found && i < q->nr; i++) {
1037                         struct diff_filepair *p = q->queue[i];
1038                         if (((p->status == DIFF_STATUS_MODIFIED) &&
1039                              ((p->score &&
1040                                strchr(filter, DIFF_STATUS_FILTER_BROKEN)) ||
1041                               (!p->score &&
1042                                strchr(filter, DIFF_STATUS_MODIFIED)))) ||
1043                             ((p->status != DIFF_STATUS_MODIFIED) &&
1044                              strchr(filter, p->status)))
1045                                 found++;
1046                 }
1047                 if (found)
1048                         return;
1049
1050                 /* otherwise we will clear the whole queue
1051                  * by copying the empty outq at the end of this
1052                  * function, but first clear the current entries
1053                  * in the queue.
1054                  */
1055                 for (i = 0; i < q->nr; i++)
1056                         diff_free_filepair(q->queue[i]);
1057         }
1058         else {
1059                 /* Only the matching ones */
1060                 for (i = 0; i < q->nr; i++) {
1061                         struct diff_filepair *p = q->queue[i];
1062
1063                         if (((p->status == DIFF_STATUS_MODIFIED) &&
1064                              ((p->score &&
1065                                strchr(filter, DIFF_STATUS_FILTER_BROKEN)) ||
1066                               (!p->score &&
1067                                strchr(filter, DIFF_STATUS_MODIFIED)))) ||
1068                             ((p->status != DIFF_STATUS_MODIFIED) &&
1069                              strchr(filter, p->status)))
1070                                 diff_q(&outq, p);
1071                         else
1072                                 diff_free_filepair(p);
1073                 }
1074         }
1075         free(q->queue);
1076         *q = outq;
1077 }
1078
1079 void diffcore_std(const char **paths,
1080                   int detect_rename, int rename_score,
1081                   const char *pickaxe, int pickaxe_opts,
1082                   int break_opt,
1083                   const char *orderfile,
1084                   const char *filter)
1085 {
1086         if (paths && paths[0])
1087                 diffcore_pathspec(paths);
1088         if (break_opt != -1)
1089                 diffcore_break(break_opt);
1090         if (detect_rename)
1091                 diffcore_rename(detect_rename, rename_score);
1092         if (break_opt != -1)
1093                 diffcore_merge_broken();
1094         if (pickaxe)
1095                 diffcore_pickaxe(pickaxe, pickaxe_opts);
1096         if (orderfile)
1097                 diffcore_order(orderfile);
1098         diff_resolve_rename_copy();
1099         diffcore_apply_filter(filter);
1100 }
1101
1102
1103 void diffcore_std_no_resolve(const char **paths,
1104                              const char *pickaxe, int pickaxe_opts,
1105                              const char *orderfile,
1106                              const char *filter)
1107 {
1108         if (paths && paths[0])
1109                 diffcore_pathspec(paths);
1110         if (pickaxe)
1111                 diffcore_pickaxe(pickaxe, pickaxe_opts);
1112         if (orderfile)
1113                 diffcore_order(orderfile);
1114         diffcore_apply_filter(filter);
1115 }
1116
1117 void diff_addremove(int addremove, unsigned mode,
1118                     const unsigned char *sha1,
1119                     const char *base, const char *path)
1120 {
1121         char concatpath[PATH_MAX];
1122         struct diff_filespec *one, *two;
1123
1124         /* This may look odd, but it is a preparation for
1125          * feeding "there are unchanged files which should
1126          * not produce diffs, but when you are doing copy
1127          * detection you would need them, so here they are"
1128          * entries to the diff-core.  They will be prefixed
1129          * with something like '=' or '*' (I haven't decided
1130          * which but should not make any difference).
1131          * Feeding the same new and old to diff_change() 
1132          * also has the same effect.
1133          * Before the final output happens, they are pruned after
1134          * merged into rename/copy pairs as appropriate.
1135          */
1136         if (reverse_diff)
1137                 addremove = (addremove == '+' ? '-' :
1138                              addremove == '-' ? '+' : addremove);
1139
1140         if (!path) path = "";
1141         sprintf(concatpath, "%s%s", base, path);
1142         one = alloc_filespec(concatpath);
1143         two = alloc_filespec(concatpath);
1144
1145         if (addremove != '+')
1146                 fill_filespec(one, sha1, mode);
1147         if (addremove != '-')
1148                 fill_filespec(two, sha1, mode);
1149
1150         diff_queue(&diff_queued_diff, one, two);
1151 }
1152
1153 void diff_helper_input(unsigned old_mode,
1154                        unsigned new_mode,
1155                        const unsigned char *old_sha1,
1156                        const unsigned char *new_sha1,
1157                        const char *old_path,
1158                        int status,
1159                        int score,
1160                        const char *new_path)
1161 {
1162         struct diff_filespec *one, *two;
1163         struct diff_filepair *dp;
1164
1165         one = alloc_filespec(old_path);
1166         two = alloc_filespec(new_path);
1167         if (old_mode)
1168                 fill_filespec(one, old_sha1, old_mode);
1169         if (new_mode)
1170                 fill_filespec(two, new_sha1, new_mode);
1171         dp = diff_queue(&diff_queued_diff, one, two);
1172         dp->score = score * MAX_SCORE / 100;
1173         dp->status = status;
1174 }
1175
1176 void diff_change(unsigned old_mode, unsigned new_mode,
1177                  const unsigned char *old_sha1,
1178                  const unsigned char *new_sha1,
1179                  const char *base, const char *path) 
1180 {
1181         char concatpath[PATH_MAX];
1182         struct diff_filespec *one, *two;
1183
1184         if (reverse_diff) {
1185                 unsigned tmp;
1186                 const unsigned char *tmp_c;
1187                 tmp = old_mode; old_mode = new_mode; new_mode = tmp;
1188                 tmp_c = old_sha1; old_sha1 = new_sha1; new_sha1 = tmp_c;
1189         }
1190         if (!path) path = "";
1191         sprintf(concatpath, "%s%s", base, path);
1192         one = alloc_filespec(concatpath);
1193         two = alloc_filespec(concatpath);
1194         fill_filespec(one, old_sha1, old_mode);
1195         fill_filespec(two, new_sha1, new_mode);
1196
1197         diff_queue(&diff_queued_diff, one, two);
1198 }
1199
1200 void diff_unmerge(const char *path)
1201 {
1202         struct diff_filespec *one, *two;
1203         one = alloc_filespec(path);
1204         two = alloc_filespec(path);
1205         diff_queue(&diff_queued_diff, one, two);
1206 }