[PATCH] Re-Fix SIGSEGV on unmerged files in git-diff-files -p
[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 "diff.h"
9 #include "diffcore.h"
10
11 static const char *diff_opts = "-pu";
12 static unsigned char null_sha1[20] = { 0, };
13
14 static int reverse_diff;
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
22         if (done_preparing)
23                 return external_diff_cmd;
24
25         /*
26          * Default values above are meant to match the
27          * Linux kernel development style.  Examples of
28          * alternative styles you can specify via environment
29          * variables are:
30          *
31          * GIT_DIFF_OPTS="-c";
32          */
33         if (gitenv("GIT_EXTERNAL_DIFF"))
34                 external_diff_cmd = gitenv("GIT_EXTERNAL_DIFF");
35
36         /* In case external diff fails... */
37         diff_opts = gitenv("GIT_DIFF_OPTS") ? : diff_opts;
38
39         done_preparing = 1;
40         return external_diff_cmd;
41 }
42
43 /* Help to copy the thing properly quoted for the shell safety.
44  * any single quote is replaced with '\'', and the caller is
45  * expected to enclose the result within a single quote pair.
46  *
47  * E.g.
48  *  original     sq_expand     result
49  *  name     ==> name      ==> 'name'
50  *  a b      ==> a b       ==> 'a b'
51  *  a'b      ==> a'\''b    ==> 'a'\''b'
52  */
53 static char *sq_expand(const char *src)
54 {
55         static char *buf = NULL;
56         int cnt, c;
57         const char *cp;
58         char *bp;
59
60         /* count bytes needed to store the quoted string. */
61         for (cnt = 1, cp = src; *cp; cnt++, cp++)
62                 if (*cp == '\'')
63                         cnt += 3;
64
65         buf = xmalloc(cnt);
66         bp = buf;
67         while ((c = *src++)) {
68                 if (c != '\'')
69                         *bp++ = c;
70                 else {
71                         bp = strcpy(bp, "'\\''");
72                         bp += 4;
73                 }
74         }
75         *bp = 0;
76         return buf;
77 }
78
79 static struct diff_tempfile {
80         const char *name; /* filename external diff should read from */
81         char hex[41];
82         char mode[10];
83         char tmp_path[50];
84 } diff_temp[2];
85
86 static void builtin_diff(const char *name_a,
87                          const char *name_b,
88                          struct diff_tempfile *temp,
89                          const char *xfrm_msg)
90 {
91         int i, next_at, cmd_size;
92         const char *diff_cmd = "diff -L'%s%s' -L'%s%s'";
93         const char *diff_arg  = "'%s' '%s'||:"; /* "||:" is to return 0 */
94         const char *input_name_sq[2];
95         const char *path0[2];
96         const char *path1[2];
97         const char *name_sq[2];
98         char *cmd;
99
100         name_sq[0] = sq_expand(name_a);
101         name_sq[1] = sq_expand(name_b);
102
103         /* diff_cmd and diff_arg have 6 %s in total which makes
104          * the sum of these strings 12 bytes larger than required.
105          * we use 2 spaces around diff-opts, and we need to count
106          * terminating NUL, so we subtract 9 here.
107          */
108         cmd_size = (strlen(diff_cmd) + strlen(diff_opts) +
109                         strlen(diff_arg) - 9);
110         for (i = 0; i < 2; i++) {
111                 input_name_sq[i] = sq_expand(temp[i].name);
112                 if (!strcmp(temp[i].name, "/dev/null")) {
113                         path0[i] = "/dev/null";
114                         path1[i] = "";
115                 } else {
116                         path0[i] = i ? "b/" : "a/";
117                         path1[i] = name_sq[i];
118                 }
119                 cmd_size += (strlen(path0[i]) + strlen(path1[i]) +
120                              strlen(input_name_sq[i]));
121         }
122
123         cmd = xmalloc(cmd_size);
124
125         next_at = 0;
126         next_at += snprintf(cmd+next_at, cmd_size-next_at,
127                             diff_cmd,
128                             path0[0], path1[0], path0[1], path1[1]);
129         next_at += snprintf(cmd+next_at, cmd_size-next_at,
130                             " %s ", diff_opts);
131         next_at += snprintf(cmd+next_at, cmd_size-next_at,
132                             diff_arg, input_name_sq[0], input_name_sq[1]);
133
134         printf("diff --git a/%s b/%s\n", name_a, name_b);
135         if (!path1[0][0]) {
136                 printf("new file mode %s\n", temp[1].mode);
137                 if (xfrm_msg && xfrm_msg[0])
138                         puts(xfrm_msg);
139         }
140         else if (!path1[1][0]) {
141                 printf("deleted file mode %s\n", temp[0].mode);
142                 if (xfrm_msg && xfrm_msg[0])
143                         puts(xfrm_msg);
144         }
145         else {
146                 if (strcmp(temp[0].mode, temp[1].mode)) {
147                         printf("old mode %s\n", temp[0].mode);
148                         printf("new mode %s\n", temp[1].mode);
149                 }
150                 if (xfrm_msg && xfrm_msg[0])
151                         puts(xfrm_msg);
152
153                 if (strncmp(temp[0].mode, temp[1].mode, 3))
154                         /* we do not run diff between different kind
155                          * of objects.
156                          */
157                         exit(0);
158         }
159         fflush(NULL);
160         execlp("/bin/sh","sh", "-c", cmd, NULL);
161 }
162
163 struct diff_filespec *alloc_filespec(const char *path)
164 {
165         int namelen = strlen(path);
166         struct diff_filespec *spec = xmalloc(sizeof(*spec) + namelen + 1);
167         spec->path = (char *)(spec + 1);
168         strcpy(spec->path, path);
169         spec->should_free = spec->should_munmap = 0;
170         spec->xfrm_flags = 0;
171         spec->size = 0;
172         spec->data = NULL;
173         spec->mode = 0;
174         memset(spec->sha1, 0, 20);
175         return spec;
176 }
177
178 void fill_filespec(struct diff_filespec *spec, const unsigned char *sha1,
179                    unsigned short mode)
180 {
181         if (mode) {
182                 spec->mode = DIFF_FILE_CANON_MODE(mode);
183                 memcpy(spec->sha1, sha1, 20);
184                 spec->sha1_valid = !!memcmp(sha1, null_sha1, 20);
185         }
186 }
187
188 /*
189  * Given a name and sha1 pair, if the dircache tells us the file in
190  * the work tree has that object contents, return true, so that
191  * prepare_temp_file() does not have to inflate and extract.
192  */
193 static int work_tree_matches(const char *name, const unsigned char *sha1)
194 {
195         struct cache_entry *ce;
196         struct stat st;
197         int pos, len;
198
199         /* We do not read the cache ourselves here, because the
200          * benchmark with my previous version that always reads cache
201          * shows that it makes things worse for diff-tree comparing
202          * two linux-2.6 kernel trees in an already checked out work
203          * tree.  This is because most diff-tree comparisons deal with
204          * only a small number of files, while reading the cache is
205          * expensive for a large project, and its cost outweighs the
206          * savings we get by not inflating the object to a temporary
207          * file.  Practically, this code only helps when we are used
208          * by diff-cache --cached, which does read the cache before
209          * calling us.
210          */
211         if (!active_cache)
212                 return 0;
213
214         len = strlen(name);
215         pos = cache_name_pos(name, len);
216         if (pos < 0)
217                 return 0;
218         ce = active_cache[pos];
219         if ((lstat(name, &st) < 0) ||
220             !S_ISREG(st.st_mode) || /* careful! */
221             ce_match_stat(ce, &st) ||
222             memcmp(sha1, ce->sha1, 20))
223                 return 0;
224         /* we return 1 only when we can stat, it is a regular file,
225          * stat information matches, and sha1 recorded in the cache
226          * matches.  I.e. we know the file in the work tree really is
227          * the same as the <name, sha1> pair.
228          */
229         return 1;
230 }
231
232 static struct sha1_size_cache {
233         unsigned char sha1[20];
234         unsigned long size;
235 } **sha1_size_cache;
236 static int sha1_size_cache_nr, sha1_size_cache_alloc;
237
238 static struct sha1_size_cache *locate_size_cache(unsigned char *sha1,
239                                                  int find_only,
240                                                  unsigned long size)
241 {
242         int first, last;
243         struct sha1_size_cache *e;
244
245         first = 0;
246         last = sha1_size_cache_nr;
247         while (last > first) {
248                 int cmp, next = (last + first) >> 1;
249                 e = sha1_size_cache[next];
250                 cmp = memcmp(e->sha1, sha1, 20);
251                 if (!cmp)
252                         return e;
253                 if (cmp < 0) {
254                         last = next;
255                         continue;
256                 }
257                 first = next+1;
258         }
259         /* not found */
260         if (find_only)
261                 return NULL;
262         /* insert to make it at "first" */
263         if (sha1_size_cache_alloc <= sha1_size_cache_nr) {
264                 sha1_size_cache_alloc = alloc_nr(sha1_size_cache_alloc);
265                 sha1_size_cache = xrealloc(sha1_size_cache,
266                                            sha1_size_cache_alloc *
267                                            sizeof(*sha1_size_cache));
268         }
269         sha1_size_cache_nr++;
270         if (first < sha1_size_cache_nr)
271                 memmove(sha1_size_cache + first + 1, sha1_size_cache + first,
272                         (sha1_size_cache_nr - first - 1) *
273                         sizeof(*sha1_size_cache));
274         e = xmalloc(sizeof(struct sha1_size_cache));
275         sha1_size_cache[first] = e;
276         memcpy(e->sha1, sha1, 20);
277         e->size = size;
278         return e;
279 }
280
281 /*
282  * While doing rename detection and pickaxe operation, we may need to
283  * grab the data for the blob (or file) for our own in-core comparison.
284  * diff_filespec has data and size fields for this purpose.
285  */
286 int diff_populate_filespec(struct diff_filespec *s, int size_only)
287 {
288         int err = 0;
289         if (!DIFF_FILE_VALID(s))
290                 die("internal error: asking to populate invalid file.");
291         if (S_ISDIR(s->mode))
292                 return -1;
293
294         if (!use_size_cache)
295                 size_only = 0;
296
297         if (s->data)
298                 return err;
299         if (!s->sha1_valid ||
300             work_tree_matches(s->path, s->sha1)) {
301                 struct stat st;
302                 int fd;
303                 if (lstat(s->path, &st) < 0) {
304                         if (errno == ENOENT) {
305                         err_empty:
306                                 err = -1;
307                         empty:
308                                 s->data = "";
309                                 s->size = 0;
310                                 return err;
311                         }
312                 }
313                 s->size = st.st_size;
314                 if (!s->size)
315                         goto empty;
316                 if (size_only)
317                         return 0;
318                 if (S_ISLNK(st.st_mode)) {
319                         int ret;
320                         s->data = xmalloc(s->size);
321                         s->should_free = 1;
322                         ret = readlink(s->path, s->data, s->size);
323                         if (ret < 0) {
324                                 free(s->data);
325                                 goto err_empty;
326                         }
327                         return 0;
328                 }
329                 fd = open(s->path, O_RDONLY);
330                 if (fd < 0)
331                         goto err_empty;
332                 s->data = mmap(NULL, s->size, PROT_READ, MAP_PRIVATE, fd, 0);
333                 s->should_munmap = 1;
334                 close(fd);
335         }
336         else {
337                 char type[20];
338                 struct sha1_size_cache *e;
339
340                 if (size_only) {
341                         e = locate_size_cache(s->sha1, 1, 0);
342                         if (e) {
343                                 s->size = e->size;
344                                 return 0;
345                         }
346                         if (!sha1_file_size(s->sha1, &s->size))
347                                 locate_size_cache(s->sha1, 0, s->size);
348                 }
349                 else {
350                         s->data = read_sha1_file(s->sha1, type, &s->size);
351                         s->should_free = 1;
352                 }
353         }
354         return 0;
355 }
356
357 void diff_free_filespec_data(struct diff_filespec *s)
358 {
359         if (s->should_free)
360                 free(s->data);
361         else if (s->should_munmap)
362                 munmap(s->data, s->size);
363         s->should_free = s->should_munmap = 0;
364         s->data = NULL;
365 }
366
367 static void prep_temp_blob(struct diff_tempfile *temp,
368                            void *blob,
369                            unsigned long size,
370                            unsigned char *sha1,
371                            int mode)
372 {
373         int fd;
374
375         strcpy(temp->tmp_path, ".diff_XXXXXX");
376         fd = mkstemp(temp->tmp_path);
377         if (fd < 0)
378                 die("unable to create temp-file");
379         if (write(fd, blob, size) != size)
380                 die("unable to write temp-file");
381         close(fd);
382         temp->name = temp->tmp_path;
383         strcpy(temp->hex, sha1_to_hex(sha1));
384         temp->hex[40] = 0;
385         sprintf(temp->mode, "%06o", mode);
386 }
387
388 static void prepare_temp_file(const char *name,
389                               struct diff_tempfile *temp,
390                               struct diff_filespec *one)
391 {
392         if (!DIFF_FILE_VALID(one)) {
393         not_a_valid_file:
394                 /* A '-' entry produces this for file-2, and
395                  * a '+' entry produces this for file-1.
396                  */
397                 temp->name = "/dev/null";
398                 strcpy(temp->hex, ".");
399                 strcpy(temp->mode, ".");
400                 return;
401         }
402
403         if (!one->sha1_valid ||
404             work_tree_matches(name, one->sha1)) {
405                 struct stat st;
406                 if (lstat(name, &st) < 0) {
407                         if (errno == ENOENT)
408                                 goto not_a_valid_file;
409                         die("stat(%s): %s", name, strerror(errno));
410                 }
411                 if (S_ISLNK(st.st_mode)) {
412                         int ret;
413                         char *buf, buf_[1024];
414                         buf = ((sizeof(buf_) < st.st_size) ?
415                                xmalloc(st.st_size) : buf_);
416                         ret = readlink(name, buf, st.st_size);
417                         if (ret < 0)
418                                 die("readlink(%s)", name);
419                         prep_temp_blob(temp, buf, st.st_size,
420                                        (one->sha1_valid ?
421                                         one->sha1 : null_sha1),
422                                        (one->sha1_valid ?
423                                         one->mode : S_IFLNK));
424                 }
425                 else {
426                         /* we can borrow from the file in the work tree */
427                         temp->name = name;
428                         if (!one->sha1_valid)
429                                 strcpy(temp->hex, sha1_to_hex(null_sha1));
430                         else
431                                 strcpy(temp->hex, sha1_to_hex(one->sha1));
432                         /* Even though we may sometimes borrow the
433                          * contents from the work tree, we always want
434                          * one->mode.  mode is trustworthy even when
435                          * !(one->sha1_valid), as long as
436                          * DIFF_FILE_VALID(one).
437                          */
438                         sprintf(temp->mode, "%06o", one->mode);
439                 }
440                 return;
441         }
442         else {
443                 if (diff_populate_filespec(one, 0))
444                         die("cannot read data blob for %s", one->path);
445                 prep_temp_blob(temp, one->data, one->size,
446                                one->sha1, one->mode);
447         }
448 }
449
450 static void remove_tempfile(void)
451 {
452         int i;
453
454         for (i = 0; i < 2; i++)
455                 if (diff_temp[i].name == diff_temp[i].tmp_path) {
456                         unlink(diff_temp[i].name);
457                         diff_temp[i].name = NULL;
458                 }
459 }
460
461 static void remove_tempfile_on_signal(int signo)
462 {
463         remove_tempfile();
464 }
465
466 /* An external diff command takes:
467  *
468  * diff-cmd name infile1 infile1-sha1 infile1-mode \
469  *               infile2 infile2-sha1 infile2-mode [ rename-to ]
470  *
471  */
472 static void run_external_diff(const char *pgm,
473                               const char *name,
474                               const char *other,
475                               struct diff_filespec *one,
476                               struct diff_filespec *two,
477                               const char *xfrm_msg)
478 {
479         struct diff_tempfile *temp = diff_temp;
480         pid_t pid;
481         int status;
482         static int atexit_asked = 0;
483
484         if (one && two) {
485                 prepare_temp_file(name, &temp[0], one);
486                 prepare_temp_file(other ? : name, &temp[1], two);
487                 if (! atexit_asked &&
488                     (temp[0].name == temp[0].tmp_path ||
489                      temp[1].name == temp[1].tmp_path)) {
490                         atexit_asked = 1;
491                         atexit(remove_tempfile);
492                 }
493                 signal(SIGINT, remove_tempfile_on_signal);
494         }
495
496         fflush(NULL);
497         pid = fork();
498         if (pid < 0)
499                 die("unable to fork");
500         if (!pid) {
501                 if (pgm) {
502                         if (one && two) {
503                                 const char *exec_arg[10];
504                                 const char **arg = &exec_arg[0];
505                                 *arg++ = pgm;
506                                 *arg++ = name;
507                                 *arg++ = temp[0].name;
508                                 *arg++ = temp[0].hex;
509                                 *arg++ = temp[0].mode;
510                                 *arg++ = temp[1].name;
511                                 *arg++ = temp[1].hex;
512                                 *arg++ = temp[1].mode;
513                                 if (other) {
514                                         *arg++ = other;
515                                         *arg++ = xfrm_msg;
516                                 }
517                                 *arg = NULL;
518                                 execvp(pgm, (char *const*) exec_arg);
519                         }
520                         else
521                                 execlp(pgm, pgm, name, NULL);
522                 }
523                 /*
524                  * otherwise we use the built-in one.
525                  */
526                 if (one && two)
527                         builtin_diff(name, other ? : name, temp, xfrm_msg);
528                 else
529                         printf("* Unmerged path %s\n", name);
530                 exit(0);
531         }
532         if (waitpid(pid, &status, 0) < 0 ||
533             !WIFEXITED(status) || WEXITSTATUS(status)) {
534                 /* Earlier we did not check the exit status because
535                  * diff exits non-zero if files are different, and
536                  * we are not interested in knowing that.  It was a
537                  * mistake which made it harder to quit a diff-*
538                  * session that uses the git-apply-patch-script as
539                  * the GIT_EXTERNAL_DIFF.  A custom GIT_EXTERNAL_DIFF
540                  * should also exit non-zero only when it wants to
541                  * abort the entire diff-* session.
542                  */
543                 remove_tempfile();
544                 fprintf(stderr, "external diff died, stopping at %s.\n", name);
545                 exit(1);
546         }
547         remove_tempfile();
548 }
549
550 static void run_diff(const char *name,
551                      const char *other,
552                      struct diff_filespec *one,
553                      struct diff_filespec *two,
554                      const char *xfrm_msg)
555 {
556         const char *pgm = external_diff();
557         if (!pgm &&
558             one && two &&
559             DIFF_FILE_VALID(one) && DIFF_FILE_VALID(two) &&
560             (S_IFMT & one->mode) != (S_IFMT & two->mode)) {
561                 /* a filepair that changes between file and symlink
562                  * needs to be split into deletion and creation.
563                  */
564                 struct diff_filespec *null = alloc_filespec(two->path);
565                 run_external_diff(NULL, name, other, one, null, xfrm_msg);
566                 free(null);
567                 null = alloc_filespec(one->path);
568                 run_external_diff(NULL, name, other, null, two, xfrm_msg);
569                 free(null);
570         }
571         else
572                 run_external_diff(pgm, name, other, one, two, xfrm_msg);
573 }
574
575 void diff_setup(int flags)
576 {
577         if (flags & DIFF_SETUP_REVERSE)
578                 reverse_diff = 1;
579         if (flags & DIFF_SETUP_USE_CACHE) {
580                 if (!active_cache)
581                         /* read-cache does not die even when it fails
582                          * so it is safe for us to do this here.  Also
583                          * it does not smudge active_cache or active_nr
584                          * when it fails, so we do not have to worry about
585                          * cleaning it up oufselves either.
586                          */
587                         read_cache();
588         }
589         if (flags & DIFF_SETUP_USE_SIZE_CACHE)
590                 use_size_cache = 1;
591         
592 }
593
594 static int parse_num(const char **cp_p)
595 {
596         int num, scale, ch, cnt;
597         const char *cp = *cp_p;
598
599         cnt = num = 0;
600         scale = 1;
601         while ('0' <= (ch = *cp) && ch <= '9') {
602                 if (cnt++ < 5) {
603                         /* We simply ignore more than 5 digits precision. */
604                         scale *= 10;
605                         num = num * 10 + ch - '0';
606                 }
607                 *cp++;
608         }
609         *cp_p = cp;
610
611         /* user says num divided by scale and we say internally that
612          * is MAX_SCORE * num / scale.
613          */
614         return (MAX_SCORE * num / scale);
615 }
616
617 int diff_scoreopt_parse(const char *opt)
618 {
619         int opt1, opt2, cmd;
620
621         if (*opt++ != '-')
622                 return -1;
623         cmd = *opt++;
624         if (cmd != 'M' && cmd != 'C' && cmd != 'B')
625                 return -1; /* that is not a -M, -C nor -B option */
626
627         opt1 = parse_num(&opt);
628         if (cmd != 'B')
629                 opt2 = 0;
630         else {
631                 if (*opt == 0)
632                         opt2 = 0;
633                 else if (*opt != '/')
634                         return -1; /* we expect -B80/99 or -B80 */
635                 else {
636                         opt++;
637                         opt2 = parse_num(&opt);
638                 }
639         }
640         if (*opt != 0)
641                 return -1;
642         return opt1 | (opt2 << 16);
643 }
644
645 struct diff_queue_struct diff_queued_diff;
646
647 void diff_q(struct diff_queue_struct *queue, struct diff_filepair *dp)
648 {
649         if (queue->alloc <= queue->nr) {
650                 queue->alloc = alloc_nr(queue->alloc);
651                 queue->queue = xrealloc(queue->queue,
652                                         sizeof(dp) * queue->alloc);
653         }
654         queue->queue[queue->nr++] = dp;
655 }
656
657 struct diff_filepair *diff_queue(struct diff_queue_struct *queue,
658                                  struct diff_filespec *one,
659                                  struct diff_filespec *two)
660 {
661         struct diff_filepair *dp = xmalloc(sizeof(*dp));
662         dp->one = one;
663         dp->two = two;
664         dp->score = 0;
665         dp->source_stays = 0;
666         dp->broken_pair = 0;
667         diff_q(queue, dp);
668         return dp;
669 }
670
671 void diff_free_filepair(struct diff_filepair *p)
672 {
673         diff_free_filespec_data(p->one);
674         diff_free_filespec_data(p->two);
675         free(p);
676 }
677
678 static void diff_flush_raw(struct diff_filepair *p,
679                            int line_termination,
680                            int inter_name_termination)
681 {
682         int two_paths;
683         char status[10];
684
685         if (line_termination) {
686                 const char *err = "path %s cannot be expressed without -z";
687                 if (strchr(p->one->path, line_termination) ||
688                     strchr(p->one->path, inter_name_termination))
689                         die(err, p->one->path);
690                 if (strchr(p->two->path, line_termination) ||
691                     strchr(p->two->path, inter_name_termination))
692                         die(err, p->two->path);
693         }
694
695         switch (p->status) {
696         case 'C': case 'R':
697                 two_paths = 1;
698                 sprintf(status, "%c%03d", p->status,
699                         (int)(0.5 + p->score * 100.0/MAX_SCORE));
700                 break;
701         case 'N': case 'D':
702                 two_paths = 0;
703                 if (p->score)
704                         sprintf(status, "%c%03d", p->status,
705                                 (int)(0.5 + p->score * 100.0/MAX_SCORE));
706                 else {
707                         status[0] = p->status;
708                         status[1] = 0;
709                 }
710                 break;
711         default:
712                 two_paths = 0;
713                 status[0] = p->status;
714                 status[1] = 0;
715                 break;
716         }
717         printf(":%06o %06o %s ",
718                p->one->mode, p->two->mode, sha1_to_hex(p->one->sha1));
719         printf("%s %s%c%s",
720                sha1_to_hex(p->two->sha1),
721                status,
722                inter_name_termination,
723                p->one->path);
724         if (two_paths)
725                 printf("%c%s", inter_name_termination, p->two->path);
726         putchar(line_termination);
727 }
728
729 int diff_unmodified_pair(struct diff_filepair *p)
730 {
731         /* This function is written stricter than necessary to support
732          * the currently implemented transformers, but the idea is to
733          * let transformers to produce diff_filepairs any way they want,
734          * and filter and clean them up here before producing the output.
735          */
736         struct diff_filespec *one, *two;
737
738         if (DIFF_PAIR_UNMERGED(p))
739                 return 0; /* unmerged is interesting */
740
741         one = p->one;
742         two = p->two;
743
744         /* deletion, addition, mode or type change
745          * and rename are all interesting.
746          */
747         if (DIFF_FILE_VALID(one) != DIFF_FILE_VALID(two) ||
748             DIFF_PAIR_MODE_CHANGED(p) ||
749             strcmp(one->path, two->path))
750                 return 0;
751
752         /* both are valid and point at the same path.  that is, we are
753          * dealing with a change.
754          */
755         if (one->sha1_valid && two->sha1_valid &&
756             !memcmp(one->sha1, two->sha1, sizeof(one->sha1)))
757                 return 1; /* no change */
758         if (!one->sha1_valid && !two->sha1_valid)
759                 return 1; /* both look at the same file on the filesystem. */
760         return 0;
761 }
762
763 static void diff_flush_patch(struct diff_filepair *p)
764 {
765         const char *name, *other;
766         char msg_[PATH_MAX*2+200], *msg;
767
768         if (diff_unmodified_pair(p))
769                 return;
770
771         name = p->one->path;
772         other = (strcmp(name, p->two->path) ? p->two->path : NULL);
773         if ((DIFF_FILE_VALID(p->one) && S_ISDIR(p->one->mode)) ||
774             (DIFF_FILE_VALID(p->two) && S_ISDIR(p->two->mode)))
775                 return; /* no tree diffs in patch format */ 
776
777         switch (p->status) {
778         case 'C':
779                 sprintf(msg_,
780                         "similarity index %d%%\n"
781                         "copy from %s\n"
782                         "copy to %s",
783                         (int)(0.5 + p->score * 100.0/MAX_SCORE),
784                         p->one->path, p->two->path);
785                 msg = msg_;
786                 break;
787         case 'R':
788                 sprintf(msg_,
789                         "similarity index %d%%\n"
790                         "rename from %s\n"
791                         "rename to %s",
792                         (int)(0.5 + p->score * 100.0/MAX_SCORE),
793                         p->one->path, p->two->path);
794                 msg = msg_;
795                 break;
796         case 'D': case 'N':
797                 if (DIFF_PAIR_BROKEN(p)) {
798                         sprintf(msg_,
799                                 "dissimilarity index %d%%",
800                                 (int)(0.5 + p->score * 100.0/MAX_SCORE));
801                         msg = msg_;
802                 }
803                 else
804                         msg = NULL;
805                 break;
806         default:
807                 msg = NULL;
808         }
809
810         if (DIFF_PAIR_UNMERGED(p))
811                 run_diff(name, NULL, NULL, NULL, NULL);
812         else
813                 run_diff(name, other, p->one, p->two, msg);
814 }
815
816 int diff_queue_is_empty(void)
817 {
818         struct diff_queue_struct *q = &diff_queued_diff;
819         int i;
820         for (i = 0; i < q->nr; i++)
821                 if (!diff_unmodified_pair(q->queue[i]))
822                         return 0;
823         return 1;
824 }
825
826 #if DIFF_DEBUG
827 void diff_debug_filespec(struct diff_filespec *s, int x, const char *one)
828 {
829         fprintf(stderr, "queue[%d] %s (%s) %s %06o %s\n",
830                 x, one ? : "",
831                 s->path,
832                 DIFF_FILE_VALID(s) ? "valid" : "invalid",
833                 s->mode,
834                 s->sha1_valid ? sha1_to_hex(s->sha1) : "");
835         fprintf(stderr, "queue[%d] %s size %lu flags %d\n",
836                 x, one ? : "",
837                 s->size, s->xfrm_flags);
838 }
839
840 void diff_debug_filepair(const struct diff_filepair *p, int i)
841 {
842         diff_debug_filespec(p->one, i, "one");
843         diff_debug_filespec(p->two, i, "two");
844         fprintf(stderr, "score %d, status %c stays %d broken %d\n",
845                 p->score, p->status ? : '?',
846                 p->source_stays, p->broken_pair);
847 }
848
849 void diff_debug_queue(const char *msg, struct diff_queue_struct *q)
850 {
851         int i;
852         if (msg)
853                 fprintf(stderr, "%s\n", msg);
854         fprintf(stderr, "q->nr = %d\n", q->nr);
855         for (i = 0; i < q->nr; i++) {
856                 struct diff_filepair *p = q->queue[i];
857                 diff_debug_filepair(p, i);
858         }
859 }
860 #endif
861
862 static void diff_resolve_rename_copy(void)
863 {
864         int i, j;
865         struct diff_filepair *p, *pp;
866         struct diff_queue_struct *q = &diff_queued_diff;
867
868         diff_debug_queue("resolve-rename-copy", q);
869
870         for (i = 0; i < q->nr; i++) {
871                 p = q->queue[i];
872                 p->status = 0; /* undecided */
873                 if (DIFF_PAIR_UNMERGED(p))
874                         p->status = 'U';
875                 else if (!DIFF_FILE_VALID(p->one))
876                         p->status = 'N';
877                 else if (!DIFF_FILE_VALID(p->two))
878                         p->status = 'D';
879                 else if (DIFF_PAIR_TYPE_CHANGED(p))
880                         p->status = 'T';
881
882                 /* from this point on, we are dealing with a pair
883                  * whose both sides are valid and of the same type, i.e.
884                  * either in-place edit or rename/copy edit.
885                  */
886                 else if (DIFF_PAIR_RENAME(p)) {
887                         if (p->source_stays) {
888                                 p->status = 'C';
889                                 continue;
890                         }
891                         /* See if there is some other filepair that
892                          * copies from the same source as us.  If so
893                          * we are a copy.  Otherwise we are a rename.
894                          */
895                         for (j = i + 1; j < q->nr; j++) {
896                                 pp = q->queue[j];
897                                 if (strcmp(pp->one->path, p->one->path))
898                                         continue; /* not us */
899                                 if (!DIFF_PAIR_RENAME(pp))
900                                         continue; /* not a rename/copy */
901                                 /* pp is a rename/copy from the same source */
902                                 p->status = 'C';
903                                 break;
904                         }
905                         if (!p->status)
906                                 p->status = 'R';
907                 }
908                 else if (memcmp(p->one->sha1, p->two->sha1, 20) ||
909                          p->one->mode != p->two->mode)
910                         p->status = 'M';
911                 else {
912                         /* This is a "no-change" entry and should not
913                          * happen anymore, but prepare for broken callers.
914                          */
915                         error("feeding unmodified %s to diffcore",
916                               p->one->path);
917                         p->status = 'X';
918                 }
919         }
920         diff_debug_queue("resolve-rename-copy done", q);
921 }
922
923 void diff_flush(int diff_output_style, int resolve_rename_copy)
924 {
925         struct diff_queue_struct *q = &diff_queued_diff;
926         int i;
927         int line_termination = '\n';
928         int inter_name_termination = '\t';
929
930         if (diff_output_style == DIFF_FORMAT_MACHINE)
931                 line_termination = inter_name_termination = 0;
932         if (resolve_rename_copy)
933                 diff_resolve_rename_copy();
934
935         for (i = 0; i < q->nr; i++) {
936                 struct diff_filepair *p = q->queue[i];
937                 if ((diff_output_style == DIFF_FORMAT_NO_OUTPUT) ||
938                     (p->status == 'X'))
939                         continue;
940                 if (p->status == 0)
941                         die("internal error in diff-resolve-rename-copy");
942                 switch (diff_output_style) {
943                 case DIFF_FORMAT_PATCH:
944                         diff_flush_patch(p);
945                         break;
946                 case DIFF_FORMAT_HUMAN:
947                 case DIFF_FORMAT_MACHINE:
948                         diff_flush_raw(p, line_termination,
949                                        inter_name_termination);
950                         break;
951                 }
952         }
953         for (i = 0; i < q->nr; i++)
954                 diff_free_filepair(q->queue[i]);
955         free(q->queue);
956         q->queue = NULL;
957         q->nr = q->alloc = 0;
958 }
959
960 void diffcore_std(const char **paths,
961                   int detect_rename, int rename_score,
962                   const char *pickaxe, int pickaxe_opts,
963                   int break_opt,
964                   const char *orderfile)
965 {
966         if (paths && paths[0])
967                 diffcore_pathspec(paths);
968         if (break_opt != -1)
969                 diffcore_break(break_opt);
970         if (detect_rename)
971                 diffcore_rename(detect_rename, rename_score);
972         if (break_opt != -1)
973                 diffcore_merge_broken();
974         if (pickaxe)
975                 diffcore_pickaxe(pickaxe, pickaxe_opts);
976         if (orderfile)
977                 diffcore_order(orderfile);
978 }
979
980 void diff_addremove(int addremove, unsigned mode,
981                     const unsigned char *sha1,
982                     const char *base, const char *path)
983 {
984         char concatpath[PATH_MAX];
985         struct diff_filespec *one, *two;
986
987         /* This may look odd, but it is a preparation for
988          * feeding "there are unchanged files which should
989          * not produce diffs, but when you are doing copy
990          * detection you would need them, so here they are"
991          * entries to the diff-core.  They will be prefixed
992          * with something like '=' or '*' (I haven't decided
993          * which but should not make any difference).
994          * Feeding the same new and old to diff_change() 
995          * also has the same effect.
996          * Before the final output happens, they are pruned after
997          * merged into rename/copy pairs as appropriate.
998          */
999         if (reverse_diff)
1000                 addremove = (addremove == '+' ? '-' :
1001                              addremove == '-' ? '+' : addremove);
1002
1003         if (!path) path = "";
1004         sprintf(concatpath, "%s%s", base, path);
1005         one = alloc_filespec(concatpath);
1006         two = alloc_filespec(concatpath);
1007
1008         if (addremove != '+')
1009                 fill_filespec(one, sha1, mode);
1010         if (addremove != '-')
1011                 fill_filespec(two, sha1, mode);
1012
1013         diff_queue(&diff_queued_diff, one, two);
1014 }
1015
1016 void diff_helper_input(unsigned old_mode,
1017                        unsigned new_mode,
1018                        const unsigned char *old_sha1,
1019                        const unsigned char *new_sha1,
1020                        const char *old_path,
1021                        int status,
1022                        int score,
1023                        const char *new_path)
1024 {
1025         struct diff_filespec *one, *two;
1026         struct diff_filepair *dp;
1027
1028         one = alloc_filespec(old_path);
1029         two = alloc_filespec(new_path);
1030         if (old_mode)
1031                 fill_filespec(one, old_sha1, old_mode);
1032         if (new_mode)
1033                 fill_filespec(two, new_sha1, new_mode);
1034         dp = diff_queue(&diff_queued_diff, one, two);
1035         dp->score = score * MAX_SCORE / 100;
1036         dp->status = status;
1037 }
1038
1039 void diff_change(unsigned old_mode, unsigned new_mode,
1040                  const unsigned char *old_sha1,
1041                  const unsigned char *new_sha1,
1042                  const char *base, const char *path) 
1043 {
1044         char concatpath[PATH_MAX];
1045         struct diff_filespec *one, *two;
1046
1047         if (reverse_diff) {
1048                 unsigned tmp;
1049                 const unsigned char *tmp_c;
1050                 tmp = old_mode; old_mode = new_mode; new_mode = tmp;
1051                 tmp_c = old_sha1; old_sha1 = new_sha1; new_sha1 = tmp_c;
1052         }
1053         if (!path) path = "";
1054         sprintf(concatpath, "%s%s", base, path);
1055         one = alloc_filespec(concatpath);
1056         two = alloc_filespec(concatpath);
1057         fill_filespec(one, old_sha1, old_mode);
1058         fill_filespec(two, new_sha1, new_mode);
1059
1060         diff_queue(&diff_queued_diff, one, two);
1061 }
1062
1063 void diff_unmerge(const char *path)
1064 {
1065         struct diff_filespec *one, *two;
1066         one = alloc_filespec(path);
1067         two = alloc_filespec(path);
1068         diff_queue(&diff_queued_diff, one, two);
1069 }