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