Merge branch 'jc/again'
[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 #include "delta.h"
12 #include "xdiff-interface.h"
13
14 static int use_size_cache;
15
16 int diff_rename_limit_default = -1;
17
18 int git_diff_config(const char *var, const char *value)
19 {
20         if (!strcmp(var, "diff.renamelimit")) {
21                 diff_rename_limit_default = git_config_int(var, value);
22                 return 0;
23         }
24
25         return git_default_config(var, value);
26 }
27
28 static char *quote_one(const char *str)
29 {
30         int needlen;
31         char *xp;
32
33         if (!str)
34                 return NULL;
35         needlen = quote_c_style(str, NULL, NULL, 0);
36         if (!needlen)
37                 return strdup(str);
38         xp = xmalloc(needlen + 1);
39         quote_c_style(str, xp, NULL, 0);
40         return xp;
41 }
42
43 static char *quote_two(const char *one, const char *two)
44 {
45         int need_one = quote_c_style(one, NULL, NULL, 1);
46         int need_two = quote_c_style(two, NULL, NULL, 1);
47         char *xp;
48
49         if (need_one + need_two) {
50                 if (!need_one) need_one = strlen(one);
51                 if (!need_two) need_one = strlen(two);
52
53                 xp = xmalloc(need_one + need_two + 3);
54                 xp[0] = '"';
55                 quote_c_style(one, xp + 1, NULL, 1);
56                 quote_c_style(two, xp + need_one + 1, NULL, 1);
57                 strcpy(xp + need_one + need_two + 1, "\"");
58                 return xp;
59         }
60         need_one = strlen(one);
61         need_two = strlen(two);
62         xp = xmalloc(need_one + need_two + 1);
63         strcpy(xp, one);
64         strcpy(xp + need_one, two);
65         return xp;
66 }
67
68 static const char *external_diff(void)
69 {
70         static const char *external_diff_cmd = NULL;
71         static int done_preparing = 0;
72
73         if (done_preparing)
74                 return external_diff_cmd;
75         external_diff_cmd = getenv("GIT_EXTERNAL_DIFF");
76         done_preparing = 1;
77         return external_diff_cmd;
78 }
79
80 #define TEMPFILE_PATH_LEN               50
81
82 static struct diff_tempfile {
83         const char *name; /* filename external diff should read from */
84         char hex[41];
85         char mode[10];
86         char tmp_path[TEMPFILE_PATH_LEN];
87 } diff_temp[2];
88
89 static int count_lines(const char *data, int size)
90 {
91         int count, ch, completely_empty = 1, nl_just_seen = 0;
92         count = 0;
93         while (0 < size--) {
94                 ch = *data++;
95                 if (ch == '\n') {
96                         count++;
97                         nl_just_seen = 1;
98                         completely_empty = 0;
99                 }
100                 else {
101                         nl_just_seen = 0;
102                         completely_empty = 0;
103                 }
104         }
105         if (completely_empty)
106                 return 0;
107         if (!nl_just_seen)
108                 count++; /* no trailing newline */
109         return count;
110 }
111
112 static void print_line_count(int count)
113 {
114         switch (count) {
115         case 0:
116                 printf("0,0");
117                 break;
118         case 1:
119                 printf("1");
120                 break;
121         default:
122                 printf("1,%d", count);
123                 break;
124         }
125 }
126
127 static void copy_file(int prefix, const char *data, int size)
128 {
129         int ch, nl_just_seen = 1;
130         while (0 < size--) {
131                 ch = *data++;
132                 if (nl_just_seen)
133                         putchar(prefix);
134                 putchar(ch);
135                 if (ch == '\n')
136                         nl_just_seen = 1;
137                 else
138                         nl_just_seen = 0;
139         }
140         if (!nl_just_seen)
141                 printf("\n\\ No newline at end of file\n");
142 }
143
144 static void emit_rewrite_diff(const char *name_a,
145                               const char *name_b,
146                               struct diff_filespec *one,
147                               struct diff_filespec *two)
148 {
149         int lc_a, lc_b;
150         diff_populate_filespec(one, 0);
151         diff_populate_filespec(two, 0);
152         lc_a = count_lines(one->data, one->size);
153         lc_b = count_lines(two->data, two->size);
154         printf("--- %s\n+++ %s\n@@ -", name_a, name_b);
155         print_line_count(lc_a);
156         printf(" +");
157         print_line_count(lc_b);
158         printf(" @@\n");
159         if (lc_a)
160                 copy_file('-', one->data, one->size);
161         if (lc_b)
162                 copy_file('+', two->data, two->size);
163 }
164
165 static int fill_mmfile(mmfile_t *mf, struct diff_filespec *one)
166 {
167         if (!DIFF_FILE_VALID(one)) {
168                 mf->ptr = ""; /* does not matter */
169                 mf->size = 0;
170                 return 0;
171         }
172         else if (diff_populate_filespec(one, 0))
173                 return -1;
174         mf->ptr = one->data;
175         mf->size = one->size;
176         return 0;
177 }
178
179 struct emit_callback {
180         const char **label_path;
181 };
182
183 static int fn_out(void *priv, mmbuffer_t *mb, int nbuf)
184 {
185         int i;
186         struct emit_callback *ecbdata = priv;
187
188         if (ecbdata->label_path[0]) {
189                 printf("--- %s\n", ecbdata->label_path[0]);
190                 printf("+++ %s\n", ecbdata->label_path[1]);
191                 ecbdata->label_path[0] = ecbdata->label_path[1] = NULL;
192         }
193         for (i = 0; i < nbuf; i++)
194                 if (!fwrite(mb[i].ptr, mb[i].size, 1, stdout))
195                         return -1;
196         return 0;
197 }
198
199 static char *pprint_rename(const char *a, const char *b)
200 {
201         const char *old = a;
202         const char *new = b;
203         char *name = NULL;
204         int pfx_length, sfx_length;
205         int len_a = strlen(a);
206         int len_b = strlen(b);
207
208         /* Find common prefix */
209         pfx_length = 0;
210         while (*old && *new && *old == *new) {
211                 if (*old == '/')
212                         pfx_length = old - a + 1;
213                 old++;
214                 new++;
215         }
216
217         /* Find common suffix */
218         old = a + len_a;
219         new = b + len_b;
220         sfx_length = 0;
221         while (a <= old && b <= new && *old == *new) {
222                 if (*old == '/')
223                         sfx_length = len_a - (old - a);
224                 old--;
225                 new--;
226         }
227
228         /*
229          * pfx{mid-a => mid-b}sfx
230          * {pfx-a => pfx-b}sfx
231          * pfx{sfx-a => sfx-b}
232          * name-a => name-b
233          */
234         if (pfx_length + sfx_length) {
235                 name = xmalloc(len_a + len_b - pfx_length - sfx_length + 7);
236                 sprintf(name, "%.*s{%.*s => %.*s}%s",
237                         pfx_length, a,
238                         len_a - pfx_length - sfx_length, a + pfx_length,
239                         len_b - pfx_length - sfx_length, b + pfx_length,
240                         a + len_a - sfx_length);
241         }
242         else {
243                 name = xmalloc(len_a + len_b + 5);
244                 sprintf(name, "%s => %s", a, b);
245         }
246         return name;
247 }
248
249 struct diffstat_t {
250         struct xdiff_emit_state xm;
251
252         int nr;
253         int alloc;
254         struct diffstat_file {
255                 char *name;
256                 unsigned is_unmerged:1;
257                 unsigned is_binary:1;
258                 unsigned is_renamed:1;
259                 unsigned int added, deleted;
260         } **files;
261 };
262
263 static struct diffstat_file *diffstat_add(struct diffstat_t *diffstat,
264                                           const char *name_a,
265                                           const char *name_b)
266 {
267         struct diffstat_file *x;
268         x = xcalloc(sizeof (*x), 1);
269         if (diffstat->nr == diffstat->alloc) {
270                 diffstat->alloc = alloc_nr(diffstat->alloc);
271                 diffstat->files = xrealloc(diffstat->files,
272                                 diffstat->alloc * sizeof(x));
273         }
274         diffstat->files[diffstat->nr++] = x;
275         if (name_b) {
276                 x->name = pprint_rename(name_a, name_b);
277                 x->is_renamed = 1;
278         }
279         else
280                 x->name = strdup(name_a);
281         return x;
282 }
283
284 static void diffstat_consume(void *priv, char *line, unsigned long len)
285 {
286         struct diffstat_t *diffstat = priv;
287         struct diffstat_file *x = diffstat->files[diffstat->nr - 1];
288
289         if (line[0] == '+')
290                 x->added++;
291         else if (line[0] == '-')
292                 x->deleted++;
293 }
294
295 static const char pluses[] = "++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++";
296 static const char minuses[]= "----------------------------------------------------------------------";
297
298 static void show_stats(struct diffstat_t* data)
299 {
300         int i, len, add, del, total, adds = 0, dels = 0;
301         int max, max_change = 0, max_len = 0;
302         int total_files = data->nr;
303
304         if (data->nr == 0)
305                 return;
306
307         for (i = 0; i < data->nr; i++) {
308                 struct diffstat_file *file = data->files[i];
309
310                 len = strlen(file->name);
311                 if (max_len < len)
312                         max_len = len;
313
314                 if (file->is_binary || file->is_unmerged)
315                         continue;
316                 if (max_change < file->added + file->deleted)
317                         max_change = file->added + file->deleted;
318         }
319
320         for (i = 0; i < data->nr; i++) {
321                 char *prefix = "";
322                 char *name = data->files[i]->name;
323                 int added = data->files[i]->added;
324                 int deleted = data->files[i]->deleted;
325
326                 if (0 < (len = quote_c_style(name, NULL, NULL, 0))) {
327                         char *qname = xmalloc(len + 1);
328                         quote_c_style(name, qname, NULL, 0);
329                         free(name);
330                         data->files[i]->name = name = qname;
331                 }
332
333                 /*
334                  * "scale" the filename
335                  */
336                 len = strlen(name);
337                 max = max_len;
338                 if (max > 50)
339                         max = 50;
340                 if (len > max) {
341                         char *slash;
342                         prefix = "...";
343                         max -= 3;
344                         name += len - max;
345                         slash = strchr(name, '/');
346                         if (slash)
347                                 name = slash;
348                 }
349                 len = max;
350
351                 /*
352                  * scale the add/delete
353                  */
354                 max = max_change;
355                 if (max + len > 70)
356                         max = 70 - len;
357
358                 if (data->files[i]->is_binary) {
359                         printf(" %s%-*s |  Bin\n", prefix, len, name);
360                         goto free_diffstat_file;
361                 }
362                 else if (data->files[i]->is_unmerged) {
363                         printf(" %s%-*s |  Unmerged\n", prefix, len, name);
364                         goto free_diffstat_file;
365                 }
366                 else if (!data->files[i]->is_renamed &&
367                          (added + deleted == 0)) {
368                         total_files--;
369                         goto free_diffstat_file;
370                 }
371
372                 add = added;
373                 del = deleted;
374                 total = add + del;
375                 adds += add;
376                 dels += del;
377
378                 if (max_change > 0) {
379                         total = (total * max + max_change / 2) / max_change;
380                         add = (add * max + max_change / 2) / max_change;
381                         del = total - add;
382                 }
383                 printf(" %s%-*s |%5d %.*s%.*s\n", prefix,
384                                 len, name, added + deleted,
385                                 add, pluses, del, minuses);
386         free_diffstat_file:
387                 free(data->files[i]->name);
388                 free(data->files[i]);
389         }
390         free(data->files);
391         printf(" %d files changed, %d insertions(+), %d deletions(-)\n",
392                         total_files, adds, dels);
393 }
394
395 static unsigned char *deflate_it(char *data,
396                                  unsigned long size,
397                                  unsigned long *result_size)
398 {
399         int bound;
400         unsigned char *deflated;
401         z_stream stream;
402
403         memset(&stream, 0, sizeof(stream));
404         deflateInit(&stream, Z_BEST_COMPRESSION);
405         bound = deflateBound(&stream, size);
406         deflated = xmalloc(bound);
407         stream.next_out = deflated;
408         stream.avail_out = bound;
409
410         stream.next_in = (unsigned char *)data;
411         stream.avail_in = size;
412         while (deflate(&stream, Z_FINISH) == Z_OK)
413                 ; /* nothing */
414         deflateEnd(&stream);
415         *result_size = stream.total_out;
416         return deflated;
417 }
418
419 static void emit_binary_diff(mmfile_t *one, mmfile_t *two)
420 {
421         void *cp;
422         void *delta;
423         void *deflated;
424         void *data;
425         unsigned long orig_size;
426         unsigned long delta_size;
427         unsigned long deflate_size;
428         unsigned long data_size;
429
430         printf("GIT binary patch\n");
431         /* We could do deflated delta, or we could do just deflated two,
432          * whichever is smaller.
433          */
434         delta = NULL;
435         deflated = deflate_it(two->ptr, two->size, &deflate_size);
436         if (one->size && two->size) {
437                 delta = diff_delta(one->ptr, one->size,
438                                    two->ptr, two->size,
439                                    &delta_size, deflate_size);
440                 if (delta) {
441                         void *to_free = delta;
442                         orig_size = delta_size;
443                         delta = deflate_it(delta, delta_size, &delta_size);
444                         free(to_free);
445                 }
446         }
447
448         if (delta && delta_size < deflate_size) {
449                 printf("delta %lu\n", orig_size);
450                 free(deflated);
451                 data = delta;
452                 data_size = delta_size;
453         }
454         else {
455                 printf("literal %lu\n", two->size);
456                 free(delta);
457                 data = deflated;
458                 data_size = deflate_size;
459         }
460
461         /* emit data encoded in base85 */
462         cp = data;
463         while (data_size) {
464                 int bytes = (52 < data_size) ? 52 : data_size;
465                 char line[70];
466                 data_size -= bytes;
467                 if (bytes <= 26)
468                         line[0] = bytes + 'A' - 1;
469                 else
470                         line[0] = bytes - 26 + 'a' - 1;
471                 encode_85(line + 1, cp, bytes);
472                 cp += bytes;
473                 puts(line);
474         }
475         printf("\n");
476         free(data);
477 }
478
479 #define FIRST_FEW_BYTES 8000
480 static int mmfile_is_binary(mmfile_t *mf)
481 {
482         long sz = mf->size;
483         if (FIRST_FEW_BYTES < sz)
484                 sz = FIRST_FEW_BYTES;
485         if (memchr(mf->ptr, 0, sz))
486                 return 1;
487         return 0;
488 }
489
490 static void builtin_diff(const char *name_a,
491                          const char *name_b,
492                          struct diff_filespec *one,
493                          struct diff_filespec *two,
494                          const char *xfrm_msg,
495                          struct diff_options *o,
496                          int complete_rewrite)
497 {
498         mmfile_t mf1, mf2;
499         const char *lbl[2];
500         char *a_one, *b_two;
501
502         a_one = quote_two("a/", name_a);
503         b_two = quote_two("b/", name_b);
504         lbl[0] = DIFF_FILE_VALID(one) ? a_one : "/dev/null";
505         lbl[1] = DIFF_FILE_VALID(two) ? b_two : "/dev/null";
506         printf("diff --git %s %s\n", a_one, b_two);
507         if (lbl[0][0] == '/') {
508                 /* /dev/null */
509                 printf("new file mode %06o\n", two->mode);
510                 if (xfrm_msg && xfrm_msg[0])
511                         puts(xfrm_msg);
512         }
513         else if (lbl[1][0] == '/') {
514                 printf("deleted file mode %06o\n", one->mode);
515                 if (xfrm_msg && xfrm_msg[0])
516                         puts(xfrm_msg);
517         }
518         else {
519                 if (one->mode != two->mode) {
520                         printf("old mode %06o\n", one->mode);
521                         printf("new mode %06o\n", two->mode);
522                 }
523                 if (xfrm_msg && xfrm_msg[0])
524                         puts(xfrm_msg);
525                 /*
526                  * we do not run diff between different kind
527                  * of objects.
528                  */
529                 if ((one->mode ^ two->mode) & S_IFMT)
530                         goto free_ab_and_return;
531                 if (complete_rewrite) {
532                         emit_rewrite_diff(name_a, name_b, one, two);
533                         goto free_ab_and_return;
534                 }
535         }
536
537         if (fill_mmfile(&mf1, one) < 0 || fill_mmfile(&mf2, two) < 0)
538                 die("unable to read files to diff");
539
540         if (mmfile_is_binary(&mf1) || mmfile_is_binary(&mf2)) {
541                 /* Quite common confusing case */
542                 if (mf1.size == mf2.size &&
543                     !memcmp(mf1.ptr, mf2.ptr, mf1.size))
544                         goto free_ab_and_return;
545                 if (o->binary)
546                         emit_binary_diff(&mf1, &mf2);
547                 else
548                         printf("Binary files %s and %s differ\n",
549                                lbl[0], lbl[1]);
550         }
551         else {
552                 /* Crazy xdl interfaces.. */
553                 const char *diffopts = getenv("GIT_DIFF_OPTS");
554                 xpparam_t xpp;
555                 xdemitconf_t xecfg;
556                 xdemitcb_t ecb;
557                 struct emit_callback ecbdata;
558
559                 ecbdata.label_path = lbl;
560                 xpp.flags = XDF_NEED_MINIMAL;
561                 xecfg.ctxlen = 3;
562                 xecfg.flags = XDL_EMIT_FUNCNAMES;
563                 if (!diffopts)
564                         ;
565                 else if (!strncmp(diffopts, "--unified=", 10))
566                         xecfg.ctxlen = strtoul(diffopts + 10, NULL, 10);
567                 else if (!strncmp(diffopts, "-u", 2))
568                         xecfg.ctxlen = strtoul(diffopts + 2, NULL, 10);
569                 ecb.outf = fn_out;
570                 ecb.priv = &ecbdata;
571                 xdl_diff(&mf1, &mf2, &xpp, &xecfg, &ecb);
572         }
573
574  free_ab_and_return:
575         free(a_one);
576         free(b_two);
577         return;
578 }
579
580 static void builtin_diffstat(const char *name_a, const char *name_b,
581                              struct diff_filespec *one,
582                              struct diff_filespec *two,
583                              struct diffstat_t *diffstat,
584                              int complete_rewrite)
585 {
586         mmfile_t mf1, mf2;
587         struct diffstat_file *data;
588
589         data = diffstat_add(diffstat, name_a, name_b);
590
591         if (!one || !two) {
592                 data->is_unmerged = 1;
593                 return;
594         }
595         if (complete_rewrite) {
596                 diff_populate_filespec(one, 0);
597                 diff_populate_filespec(two, 0);
598                 data->deleted = count_lines(one->data, one->size);
599                 data->added = count_lines(two->data, two->size);
600                 return;
601         }
602         if (fill_mmfile(&mf1, one) < 0 || fill_mmfile(&mf2, two) < 0)
603                 die("unable to read files to diff");
604
605         if (mmfile_is_binary(&mf1) || mmfile_is_binary(&mf2))
606                 data->is_binary = 1;
607         else {
608                 /* Crazy xdl interfaces.. */
609                 xpparam_t xpp;
610                 xdemitconf_t xecfg;
611                 xdemitcb_t ecb;
612
613                 xpp.flags = XDF_NEED_MINIMAL;
614                 xecfg.ctxlen = 0;
615                 xecfg.flags = 0;
616                 ecb.outf = xdiff_outf;
617                 ecb.priv = diffstat;
618                 xdl_diff(&mf1, &mf2, &xpp, &xecfg, &ecb);
619         }
620 }
621
622 struct diff_filespec *alloc_filespec(const char *path)
623 {
624         int namelen = strlen(path);
625         struct diff_filespec *spec = xmalloc(sizeof(*spec) + namelen + 1);
626
627         memset(spec, 0, sizeof(*spec));
628         spec->path = (char *)(spec + 1);
629         memcpy(spec->path, path, namelen+1);
630         return spec;
631 }
632
633 void fill_filespec(struct diff_filespec *spec, const unsigned char *sha1,
634                    unsigned short mode)
635 {
636         if (mode) {
637                 spec->mode = canon_mode(mode);
638                 memcpy(spec->sha1, sha1, 20);
639                 spec->sha1_valid = !!memcmp(sha1, null_sha1, 20);
640         }
641 }
642
643 /*
644  * Given a name and sha1 pair, if the dircache tells us the file in
645  * the work tree has that object contents, return true, so that
646  * prepare_temp_file() does not have to inflate and extract.
647  */
648 static int work_tree_matches(const char *name, const unsigned char *sha1)
649 {
650         struct cache_entry *ce;
651         struct stat st;
652         int pos, len;
653
654         /* We do not read the cache ourselves here, because the
655          * benchmark with my previous version that always reads cache
656          * shows that it makes things worse for diff-tree comparing
657          * two linux-2.6 kernel trees in an already checked out work
658          * tree.  This is because most diff-tree comparisons deal with
659          * only a small number of files, while reading the cache is
660          * expensive for a large project, and its cost outweighs the
661          * savings we get by not inflating the object to a temporary
662          * file.  Practically, this code only helps when we are used
663          * by diff-cache --cached, which does read the cache before
664          * calling us.
665          */
666         if (!active_cache)
667                 return 0;
668
669         len = strlen(name);
670         pos = cache_name_pos(name, len);
671         if (pos < 0)
672                 return 0;
673         ce = active_cache[pos];
674         if ((lstat(name, &st) < 0) ||
675             !S_ISREG(st.st_mode) || /* careful! */
676             ce_match_stat(ce, &st, 0) ||
677             memcmp(sha1, ce->sha1, 20))
678                 return 0;
679         /* we return 1 only when we can stat, it is a regular file,
680          * stat information matches, and sha1 recorded in the cache
681          * matches.  I.e. we know the file in the work tree really is
682          * the same as the <name, sha1> pair.
683          */
684         return 1;
685 }
686
687 static struct sha1_size_cache {
688         unsigned char sha1[20];
689         unsigned long size;
690 } **sha1_size_cache;
691 static int sha1_size_cache_nr, sha1_size_cache_alloc;
692
693 static struct sha1_size_cache *locate_size_cache(unsigned char *sha1,
694                                                  int find_only,
695                                                  unsigned long size)
696 {
697         int first, last;
698         struct sha1_size_cache *e;
699
700         first = 0;
701         last = sha1_size_cache_nr;
702         while (last > first) {
703                 int cmp, next = (last + first) >> 1;
704                 e = sha1_size_cache[next];
705                 cmp = memcmp(e->sha1, sha1, 20);
706                 if (!cmp)
707                         return e;
708                 if (cmp < 0) {
709                         last = next;
710                         continue;
711                 }
712                 first = next+1;
713         }
714         /* not found */
715         if (find_only)
716                 return NULL;
717         /* insert to make it at "first" */
718         if (sha1_size_cache_alloc <= sha1_size_cache_nr) {
719                 sha1_size_cache_alloc = alloc_nr(sha1_size_cache_alloc);
720                 sha1_size_cache = xrealloc(sha1_size_cache,
721                                            sha1_size_cache_alloc *
722                                            sizeof(*sha1_size_cache));
723         }
724         sha1_size_cache_nr++;
725         if (first < sha1_size_cache_nr)
726                 memmove(sha1_size_cache + first + 1, sha1_size_cache + first,
727                         (sha1_size_cache_nr - first - 1) *
728                         sizeof(*sha1_size_cache));
729         e = xmalloc(sizeof(struct sha1_size_cache));
730         sha1_size_cache[first] = e;
731         memcpy(e->sha1, sha1, 20);
732         e->size = size;
733         return e;
734 }
735
736 /*
737  * While doing rename detection and pickaxe operation, we may need to
738  * grab the data for the blob (or file) for our own in-core comparison.
739  * diff_filespec has data and size fields for this purpose.
740  */
741 int diff_populate_filespec(struct diff_filespec *s, int size_only)
742 {
743         int err = 0;
744         if (!DIFF_FILE_VALID(s))
745                 die("internal error: asking to populate invalid file.");
746         if (S_ISDIR(s->mode))
747                 return -1;
748
749         if (!use_size_cache)
750                 size_only = 0;
751
752         if (s->data)
753                 return err;
754         if (!s->sha1_valid ||
755             work_tree_matches(s->path, s->sha1)) {
756                 struct stat st;
757                 int fd;
758                 if (lstat(s->path, &st) < 0) {
759                         if (errno == ENOENT) {
760                         err_empty:
761                                 err = -1;
762                         empty:
763                                 s->data = "";
764                                 s->size = 0;
765                                 return err;
766                         }
767                 }
768                 s->size = st.st_size;
769                 if (!s->size)
770                         goto empty;
771                 if (size_only)
772                         return 0;
773                 if (S_ISLNK(st.st_mode)) {
774                         int ret;
775                         s->data = xmalloc(s->size);
776                         s->should_free = 1;
777                         ret = readlink(s->path, s->data, s->size);
778                         if (ret < 0) {
779                                 free(s->data);
780                                 goto err_empty;
781                         }
782                         return 0;
783                 }
784                 fd = open(s->path, O_RDONLY);
785                 if (fd < 0)
786                         goto err_empty;
787                 s->data = mmap(NULL, s->size, PROT_READ, MAP_PRIVATE, fd, 0);
788                 close(fd);
789                 if (s->data == MAP_FAILED)
790                         goto err_empty;
791                 s->should_munmap = 1;
792         }
793         else {
794                 char type[20];
795                 struct sha1_size_cache *e;
796
797                 if (size_only) {
798                         e = locate_size_cache(s->sha1, 1, 0);
799                         if (e) {
800                                 s->size = e->size;
801                                 return 0;
802                         }
803                         if (!sha1_object_info(s->sha1, type, &s->size))
804                                 locate_size_cache(s->sha1, 0, s->size);
805                 }
806                 else {
807                         s->data = read_sha1_file(s->sha1, type, &s->size);
808                         s->should_free = 1;
809                 }
810         }
811         return 0;
812 }
813
814 void diff_free_filespec_data(struct diff_filespec *s)
815 {
816         if (s->should_free)
817                 free(s->data);
818         else if (s->should_munmap)
819                 munmap(s->data, s->size);
820         s->should_free = s->should_munmap = 0;
821         s->data = NULL;
822         free(s->cnt_data);
823         s->cnt_data = NULL;
824 }
825
826 static void prep_temp_blob(struct diff_tempfile *temp,
827                            void *blob,
828                            unsigned long size,
829                            const unsigned char *sha1,
830                            int mode)
831 {
832         int fd;
833
834         fd = git_mkstemp(temp->tmp_path, TEMPFILE_PATH_LEN, ".diff_XXXXXX");
835         if (fd < 0)
836                 die("unable to create temp-file");
837         if (write(fd, blob, size) != size)
838                 die("unable to write temp-file");
839         close(fd);
840         temp->name = temp->tmp_path;
841         strcpy(temp->hex, sha1_to_hex(sha1));
842         temp->hex[40] = 0;
843         sprintf(temp->mode, "%06o", mode);
844 }
845
846 static void prepare_temp_file(const char *name,
847                               struct diff_tempfile *temp,
848                               struct diff_filespec *one)
849 {
850         if (!DIFF_FILE_VALID(one)) {
851         not_a_valid_file:
852                 /* A '-' entry produces this for file-2, and
853                  * a '+' entry produces this for file-1.
854                  */
855                 temp->name = "/dev/null";
856                 strcpy(temp->hex, ".");
857                 strcpy(temp->mode, ".");
858                 return;
859         }
860
861         if (!one->sha1_valid ||
862             work_tree_matches(name, one->sha1)) {
863                 struct stat st;
864                 if (lstat(name, &st) < 0) {
865                         if (errno == ENOENT)
866                                 goto not_a_valid_file;
867                         die("stat(%s): %s", name, strerror(errno));
868                 }
869                 if (S_ISLNK(st.st_mode)) {
870                         int ret;
871                         char buf[PATH_MAX + 1]; /* ought to be SYMLINK_MAX */
872                         if (sizeof(buf) <= st.st_size)
873                                 die("symlink too long: %s", name);
874                         ret = readlink(name, buf, st.st_size);
875                         if (ret < 0)
876                                 die("readlink(%s)", name);
877                         prep_temp_blob(temp, buf, st.st_size,
878                                        (one->sha1_valid ?
879                                         one->sha1 : null_sha1),
880                                        (one->sha1_valid ?
881                                         one->mode : S_IFLNK));
882                 }
883                 else {
884                         /* we can borrow from the file in the work tree */
885                         temp->name = name;
886                         if (!one->sha1_valid)
887                                 strcpy(temp->hex, sha1_to_hex(null_sha1));
888                         else
889                                 strcpy(temp->hex, sha1_to_hex(one->sha1));
890                         /* Even though we may sometimes borrow the
891                          * contents from the work tree, we always want
892                          * one->mode.  mode is trustworthy even when
893                          * !(one->sha1_valid), as long as
894                          * DIFF_FILE_VALID(one).
895                          */
896                         sprintf(temp->mode, "%06o", one->mode);
897                 }
898                 return;
899         }
900         else {
901                 if (diff_populate_filespec(one, 0))
902                         die("cannot read data blob for %s", one->path);
903                 prep_temp_blob(temp, one->data, one->size,
904                                one->sha1, one->mode);
905         }
906 }
907
908 static void remove_tempfile(void)
909 {
910         int i;
911
912         for (i = 0; i < 2; i++)
913                 if (diff_temp[i].name == diff_temp[i].tmp_path) {
914                         unlink(diff_temp[i].name);
915                         diff_temp[i].name = NULL;
916                 }
917 }
918
919 static void remove_tempfile_on_signal(int signo)
920 {
921         remove_tempfile();
922         signal(SIGINT, SIG_DFL);
923         raise(signo);
924 }
925
926 static int spawn_prog(const char *pgm, const char **arg)
927 {
928         pid_t pid;
929         int status;
930
931         fflush(NULL);
932         pid = fork();
933         if (pid < 0)
934                 die("unable to fork");
935         if (!pid) {
936                 execvp(pgm, (char *const*) arg);
937                 exit(255);
938         }
939
940         while (waitpid(pid, &status, 0) < 0) {
941                 if (errno == EINTR)
942                         continue;
943                 return -1;
944         }
945
946         /* Earlier we did not check the exit status because
947          * diff exits non-zero if files are different, and
948          * we are not interested in knowing that.  It was a
949          * mistake which made it harder to quit a diff-*
950          * session that uses the git-apply-patch-script as
951          * the GIT_EXTERNAL_DIFF.  A custom GIT_EXTERNAL_DIFF
952          * should also exit non-zero only when it wants to
953          * abort the entire diff-* session.
954          */
955         if (WIFEXITED(status) && !WEXITSTATUS(status))
956                 return 0;
957         return -1;
958 }
959
960 /* An external diff command takes:
961  *
962  * diff-cmd name infile1 infile1-sha1 infile1-mode \
963  *               infile2 infile2-sha1 infile2-mode [ rename-to ]
964  *
965  */
966 static void run_external_diff(const char *pgm,
967                               const char *name,
968                               const char *other,
969                               struct diff_filespec *one,
970                               struct diff_filespec *two,
971                               const char *xfrm_msg,
972                               int complete_rewrite)
973 {
974         const char *spawn_arg[10];
975         struct diff_tempfile *temp = diff_temp;
976         int retval;
977         static int atexit_asked = 0;
978         const char *othername;
979         const char **arg = &spawn_arg[0];
980
981         othername = (other? other : name);
982         if (one && two) {
983                 prepare_temp_file(name, &temp[0], one);
984                 prepare_temp_file(othername, &temp[1], two);
985                 if (! atexit_asked &&
986                     (temp[0].name == temp[0].tmp_path ||
987                      temp[1].name == temp[1].tmp_path)) {
988                         atexit_asked = 1;
989                         atexit(remove_tempfile);
990                 }
991                 signal(SIGINT, remove_tempfile_on_signal);
992         }
993
994         if (one && two) {
995                 *arg++ = pgm;
996                 *arg++ = name;
997                 *arg++ = temp[0].name;
998                 *arg++ = temp[0].hex;
999                 *arg++ = temp[0].mode;
1000                 *arg++ = temp[1].name;
1001                 *arg++ = temp[1].hex;
1002                 *arg++ = temp[1].mode;
1003                 if (other) {
1004                         *arg++ = other;
1005                         *arg++ = xfrm_msg;
1006                 }
1007         } else {
1008                 *arg++ = pgm;
1009                 *arg++ = name;
1010         }
1011         *arg = NULL;
1012         retval = spawn_prog(pgm, spawn_arg);
1013         remove_tempfile();
1014         if (retval) {
1015                 fprintf(stderr, "external diff died, stopping at %s.\n", name);
1016                 exit(1);
1017         }
1018 }
1019
1020 static void run_diff_cmd(const char *pgm,
1021                          const char *name,
1022                          const char *other,
1023                          struct diff_filespec *one,
1024                          struct diff_filespec *two,
1025                          const char *xfrm_msg,
1026                          struct diff_options *o,
1027                          int complete_rewrite)
1028 {
1029         if (pgm) {
1030                 run_external_diff(pgm, name, other, one, two, xfrm_msg,
1031                                   complete_rewrite);
1032                 return;
1033         }
1034         if (one && two)
1035                 builtin_diff(name, other ? other : name,
1036                              one, two, xfrm_msg, o, complete_rewrite);
1037         else
1038                 printf("* Unmerged path %s\n", name);
1039 }
1040
1041 static void diff_fill_sha1_info(struct diff_filespec *one)
1042 {
1043         if (DIFF_FILE_VALID(one)) {
1044                 if (!one->sha1_valid) {
1045                         struct stat st;
1046                         if (lstat(one->path, &st) < 0)
1047                                 die("stat %s", one->path);
1048                         if (index_path(one->sha1, one->path, &st, 0))
1049                                 die("cannot hash %s\n", one->path);
1050                 }
1051         }
1052         else
1053                 memset(one->sha1, 0, 20);
1054 }
1055
1056 static void run_diff(struct diff_filepair *p, struct diff_options *o)
1057 {
1058         const char *pgm = external_diff();
1059         char msg[PATH_MAX*2+300], *xfrm_msg;
1060         struct diff_filespec *one;
1061         struct diff_filespec *two;
1062         const char *name;
1063         const char *other;
1064         char *name_munged, *other_munged;
1065         int complete_rewrite = 0;
1066         int len;
1067
1068         if (DIFF_PAIR_UNMERGED(p)) {
1069                 /* unmerged */
1070                 run_diff_cmd(pgm, p->one->path, NULL, NULL, NULL, NULL, o, 0);
1071                 return;
1072         }
1073
1074         name = p->one->path;
1075         other = (strcmp(name, p->two->path) ? p->two->path : NULL);
1076         name_munged = quote_one(name);
1077         other_munged = quote_one(other);
1078         one = p->one; two = p->two;
1079
1080         diff_fill_sha1_info(one);
1081         diff_fill_sha1_info(two);
1082
1083         len = 0;
1084         switch (p->status) {
1085         case DIFF_STATUS_COPIED:
1086                 len += snprintf(msg + len, sizeof(msg) - len,
1087                                 "similarity index %d%%\n"
1088                                 "copy from %s\n"
1089                                 "copy to %s\n",
1090                                 (int)(0.5 + p->score * 100.0/MAX_SCORE),
1091                                 name_munged, other_munged);
1092                 break;
1093         case DIFF_STATUS_RENAMED:
1094                 len += snprintf(msg + len, sizeof(msg) - len,
1095                                 "similarity index %d%%\n"
1096                                 "rename from %s\n"
1097                                 "rename to %s\n",
1098                                 (int)(0.5 + p->score * 100.0/MAX_SCORE),
1099                                 name_munged, other_munged);
1100                 break;
1101         case DIFF_STATUS_MODIFIED:
1102                 if (p->score) {
1103                         len += snprintf(msg + len, sizeof(msg) - len,
1104                                         "dissimilarity index %d%%\n",
1105                                         (int)(0.5 + p->score *
1106                                               100.0/MAX_SCORE));
1107                         complete_rewrite = 1;
1108                         break;
1109                 }
1110                 /* fallthru */
1111         default:
1112                 /* nothing */
1113                 ;
1114         }
1115
1116         if (memcmp(one->sha1, two->sha1, 20)) {
1117                 int abbrev = o->full_index ? 40 : DEFAULT_ABBREV;
1118
1119                 len += snprintf(msg + len, sizeof(msg) - len,
1120                                 "index %.*s..%.*s",
1121                                 abbrev, sha1_to_hex(one->sha1),
1122                                 abbrev, sha1_to_hex(two->sha1));
1123                 if (one->mode == two->mode)
1124                         len += snprintf(msg + len, sizeof(msg) - len,
1125                                         " %06o", one->mode);
1126                 len += snprintf(msg + len, sizeof(msg) - len, "\n");
1127         }
1128
1129         if (len)
1130                 msg[--len] = 0;
1131         xfrm_msg = len ? msg : NULL;
1132
1133         if (!pgm &&
1134             DIFF_FILE_VALID(one) && DIFF_FILE_VALID(two) &&
1135             (S_IFMT & one->mode) != (S_IFMT & two->mode)) {
1136                 /* a filepair that changes between file and symlink
1137                  * needs to be split into deletion and creation.
1138                  */
1139                 struct diff_filespec *null = alloc_filespec(two->path);
1140                 run_diff_cmd(NULL, name, other, one, null, xfrm_msg, o, 0);
1141                 free(null);
1142                 null = alloc_filespec(one->path);
1143                 run_diff_cmd(NULL, name, other, null, two, xfrm_msg, o, 0);
1144                 free(null);
1145         }
1146         else
1147                 run_diff_cmd(pgm, name, other, one, two, xfrm_msg, o,
1148                              complete_rewrite);
1149
1150         free(name_munged);
1151         free(other_munged);
1152 }
1153
1154 static void run_diffstat(struct diff_filepair *p, struct diff_options *o,
1155                          struct diffstat_t *diffstat)
1156 {
1157         const char *name;
1158         const char *other;
1159         int complete_rewrite = 0;
1160
1161         if (DIFF_PAIR_UNMERGED(p)) {
1162                 /* unmerged */
1163                 builtin_diffstat(p->one->path, NULL, NULL, NULL, diffstat, 0);
1164                 return;
1165         }
1166
1167         name = p->one->path;
1168         other = (strcmp(name, p->two->path) ? p->two->path : NULL);
1169
1170         diff_fill_sha1_info(p->one);
1171         diff_fill_sha1_info(p->two);
1172
1173         if (p->status == DIFF_STATUS_MODIFIED && p->score)
1174                 complete_rewrite = 1;
1175         builtin_diffstat(name, other, p->one, p->two, diffstat, complete_rewrite);
1176 }
1177
1178 void diff_setup(struct diff_options *options)
1179 {
1180         memset(options, 0, sizeof(*options));
1181         options->output_format = DIFF_FORMAT_RAW;
1182         options->line_termination = '\n';
1183         options->break_opt = -1;
1184         options->rename_limit = -1;
1185
1186         options->change = diff_change;
1187         options->add_remove = diff_addremove;
1188 }
1189
1190 int diff_setup_done(struct diff_options *options)
1191 {
1192         if ((options->find_copies_harder &&
1193              options->detect_rename != DIFF_DETECT_COPY) ||
1194             (0 <= options->rename_limit && !options->detect_rename))
1195                 return -1;
1196
1197         /*
1198          * These cases always need recursive; we do not drop caller-supplied
1199          * recursive bits for other formats here.
1200          */
1201         if ((options->output_format == DIFF_FORMAT_PATCH) ||
1202             (options->output_format == DIFF_FORMAT_DIFFSTAT))
1203                 options->recursive = 1;
1204
1205         if (options->detect_rename && options->rename_limit < 0)
1206                 options->rename_limit = diff_rename_limit_default;
1207         if (options->setup & DIFF_SETUP_USE_CACHE) {
1208                 if (!active_cache)
1209                         /* read-cache does not die even when it fails
1210                          * so it is safe for us to do this here.  Also
1211                          * it does not smudge active_cache or active_nr
1212                          * when it fails, so we do not have to worry about
1213                          * cleaning it up ourselves either.
1214                          */
1215                         read_cache();
1216         }
1217         if (options->setup & DIFF_SETUP_USE_SIZE_CACHE)
1218                 use_size_cache = 1;
1219         if (options->abbrev <= 0 || 40 < options->abbrev)
1220                 options->abbrev = 40; /* full */
1221
1222         return 0;
1223 }
1224
1225 int diff_opt_parse(struct diff_options *options, const char **av, int ac)
1226 {
1227         const char *arg = av[0];
1228         if (!strcmp(arg, "-p") || !strcmp(arg, "-u"))
1229                 options->output_format = DIFF_FORMAT_PATCH;
1230         else if (!strcmp(arg, "--patch-with-raw")) {
1231                 options->output_format = DIFF_FORMAT_PATCH;
1232                 options->with_raw = 1;
1233         }
1234         else if (!strcmp(arg, "--stat"))
1235                 options->output_format = DIFF_FORMAT_DIFFSTAT;
1236         else if (!strcmp(arg, "--patch-with-stat")) {
1237                 options->output_format = DIFF_FORMAT_PATCH;
1238                 options->with_stat = 1;
1239         }
1240         else if (!strcmp(arg, "-z"))
1241                 options->line_termination = 0;
1242         else if (!strncmp(arg, "-l", 2))
1243                 options->rename_limit = strtoul(arg+2, NULL, 10);
1244         else if (!strcmp(arg, "--full-index"))
1245                 options->full_index = 1;
1246         else if (!strcmp(arg, "--binary")) {
1247                 options->output_format = DIFF_FORMAT_PATCH;
1248                 options->full_index = options->binary = 1;
1249         }
1250         else if (!strcmp(arg, "--name-only"))
1251                 options->output_format = DIFF_FORMAT_NAME;
1252         else if (!strcmp(arg, "--name-status"))
1253                 options->output_format = DIFF_FORMAT_NAME_STATUS;
1254         else if (!strcmp(arg, "-R"))
1255                 options->reverse_diff = 1;
1256         else if (!strncmp(arg, "-S", 2))
1257                 options->pickaxe = arg + 2;
1258         else if (!strcmp(arg, "-s"))
1259                 options->output_format = DIFF_FORMAT_NO_OUTPUT;
1260         else if (!strncmp(arg, "-O", 2))
1261                 options->orderfile = arg + 2;
1262         else if (!strncmp(arg, "--diff-filter=", 14))
1263                 options->filter = arg + 14;
1264         else if (!strcmp(arg, "--pickaxe-all"))
1265                 options->pickaxe_opts = DIFF_PICKAXE_ALL;
1266         else if (!strcmp(arg, "--pickaxe-regex"))
1267                 options->pickaxe_opts = DIFF_PICKAXE_REGEX;
1268         else if (!strncmp(arg, "-B", 2)) {
1269                 if ((options->break_opt =
1270                      diff_scoreopt_parse(arg)) == -1)
1271                         return -1;
1272         }
1273         else if (!strncmp(arg, "-M", 2)) {
1274                 if ((options->rename_score =
1275                      diff_scoreopt_parse(arg)) == -1)
1276                         return -1;
1277                 options->detect_rename = DIFF_DETECT_RENAME;
1278         }
1279         else if (!strncmp(arg, "-C", 2)) {
1280                 if ((options->rename_score =
1281                      diff_scoreopt_parse(arg)) == -1)
1282                         return -1;
1283                 options->detect_rename = DIFF_DETECT_COPY;
1284         }
1285         else if (!strcmp(arg, "--find-copies-harder"))
1286                 options->find_copies_harder = 1;
1287         else if (!strcmp(arg, "--abbrev"))
1288                 options->abbrev = DEFAULT_ABBREV;
1289         else if (!strncmp(arg, "--abbrev=", 9)) {
1290                 options->abbrev = strtoul(arg + 9, NULL, 10);
1291                 if (options->abbrev < MINIMUM_ABBREV)
1292                         options->abbrev = MINIMUM_ABBREV;
1293                 else if (40 < options->abbrev)
1294                         options->abbrev = 40;
1295         }
1296         else
1297                 return 0;
1298         return 1;
1299 }
1300
1301 static int parse_num(const char **cp_p)
1302 {
1303         unsigned long num, scale;
1304         int ch, dot;
1305         const char *cp = *cp_p;
1306
1307         num = 0;
1308         scale = 1;
1309         dot = 0;
1310         for(;;) {
1311                 ch = *cp;
1312                 if ( !dot && ch == '.' ) {
1313                         scale = 1;
1314                         dot = 1;
1315                 } else if ( ch == '%' ) {
1316                         scale = dot ? scale*100 : 100;
1317                         cp++;   /* % is always at the end */
1318                         break;
1319                 } else if ( ch >= '0' && ch <= '9' ) {
1320                         if ( scale < 100000 ) {
1321                                 scale *= 10;
1322                                 num = (num*10) + (ch-'0');
1323                         }
1324                 } else {
1325                         break;
1326                 }
1327                 cp++;
1328         }
1329         *cp_p = cp;
1330
1331         /* user says num divided by scale and we say internally that
1332          * is MAX_SCORE * num / scale.
1333          */
1334         return (num >= scale) ? MAX_SCORE : (MAX_SCORE * num / scale);
1335 }
1336
1337 int diff_scoreopt_parse(const char *opt)
1338 {
1339         int opt1, opt2, cmd;
1340
1341         if (*opt++ != '-')
1342                 return -1;
1343         cmd = *opt++;
1344         if (cmd != 'M' && cmd != 'C' && cmd != 'B')
1345                 return -1; /* that is not a -M, -C nor -B option */
1346
1347         opt1 = parse_num(&opt);
1348         if (cmd != 'B')
1349                 opt2 = 0;
1350         else {
1351                 if (*opt == 0)
1352                         opt2 = 0;
1353                 else if (*opt != '/')
1354                         return -1; /* we expect -B80/99 or -B80 */
1355                 else {
1356                         opt++;
1357                         opt2 = parse_num(&opt);
1358                 }
1359         }
1360         if (*opt != 0)
1361                 return -1;
1362         return opt1 | (opt2 << 16);
1363 }
1364
1365 struct diff_queue_struct diff_queued_diff;
1366
1367 void diff_q(struct diff_queue_struct *queue, struct diff_filepair *dp)
1368 {
1369         if (queue->alloc <= queue->nr) {
1370                 queue->alloc = alloc_nr(queue->alloc);
1371                 queue->queue = xrealloc(queue->queue,
1372                                         sizeof(dp) * queue->alloc);
1373         }
1374         queue->queue[queue->nr++] = dp;
1375 }
1376
1377 struct diff_filepair *diff_queue(struct diff_queue_struct *queue,
1378                                  struct diff_filespec *one,
1379                                  struct diff_filespec *two)
1380 {
1381         struct diff_filepair *dp = xmalloc(sizeof(*dp));
1382         dp->one = one;
1383         dp->two = two;
1384         dp->score = 0;
1385         dp->status = 0;
1386         dp->source_stays = 0;
1387         dp->broken_pair = 0;
1388         if (queue)
1389                 diff_q(queue, dp);
1390         return dp;
1391 }
1392
1393 void diff_free_filepair(struct diff_filepair *p)
1394 {
1395         diff_free_filespec_data(p->one);
1396         diff_free_filespec_data(p->two);
1397         free(p->one);
1398         free(p->two);
1399         free(p);
1400 }
1401
1402 /* This is different from find_unique_abbrev() in that
1403  * it stuffs the result with dots for alignment.
1404  */
1405 const char *diff_unique_abbrev(const unsigned char *sha1, int len)
1406 {
1407         int abblen;
1408         const char *abbrev;
1409         if (len == 40)
1410                 return sha1_to_hex(sha1);
1411
1412         abbrev = find_unique_abbrev(sha1, len);
1413         if (!abbrev)
1414                 return sha1_to_hex(sha1);
1415         abblen = strlen(abbrev);
1416         if (abblen < 37) {
1417                 static char hex[41];
1418                 if (len < abblen && abblen <= len + 2)
1419                         sprintf(hex, "%s%.*s", abbrev, len+3-abblen, "..");
1420                 else
1421                         sprintf(hex, "%s...", abbrev);
1422                 return hex;
1423         }
1424         return sha1_to_hex(sha1);
1425 }
1426
1427 static void diff_flush_raw(struct diff_filepair *p,
1428                            int line_termination,
1429                            int inter_name_termination,
1430                            struct diff_options *options,
1431                            int output_format)
1432 {
1433         int two_paths;
1434         char status[10];
1435         int abbrev = options->abbrev;
1436         const char *path_one, *path_two;
1437
1438         path_one = p->one->path;
1439         path_two = p->two->path;
1440         if (line_termination) {
1441                 path_one = quote_one(path_one);
1442                 path_two = quote_one(path_two);
1443         }
1444
1445         if (p->score)
1446                 sprintf(status, "%c%03d", p->status,
1447                         (int)(0.5 + p->score * 100.0/MAX_SCORE));
1448         else {
1449                 status[0] = p->status;
1450                 status[1] = 0;
1451         }
1452         switch (p->status) {
1453         case DIFF_STATUS_COPIED:
1454         case DIFF_STATUS_RENAMED:
1455                 two_paths = 1;
1456                 break;
1457         case DIFF_STATUS_ADDED:
1458         case DIFF_STATUS_DELETED:
1459                 two_paths = 0;
1460                 break;
1461         default:
1462                 two_paths = 0;
1463                 break;
1464         }
1465         if (output_format != DIFF_FORMAT_NAME_STATUS) {
1466                 printf(":%06o %06o %s ",
1467                        p->one->mode, p->two->mode,
1468                        diff_unique_abbrev(p->one->sha1, abbrev));
1469                 printf("%s ",
1470                        diff_unique_abbrev(p->two->sha1, abbrev));
1471         }
1472         printf("%s%c%s", status, inter_name_termination, path_one);
1473         if (two_paths)
1474                 printf("%c%s", inter_name_termination, path_two);
1475         putchar(line_termination);
1476         if (path_one != p->one->path)
1477                 free((void*)path_one);
1478         if (path_two != p->two->path)
1479                 free((void*)path_two);
1480 }
1481
1482 static void diff_flush_name(struct diff_filepair *p,
1483                             int inter_name_termination,
1484                             int line_termination)
1485 {
1486         char *path = p->two->path;
1487
1488         if (line_termination)
1489                 path = quote_one(p->two->path);
1490         else
1491                 path = p->two->path;
1492         printf("%s%c", path, line_termination);
1493         if (p->two->path != path)
1494                 free(path);
1495 }
1496
1497 int diff_unmodified_pair(struct diff_filepair *p)
1498 {
1499         /* This function is written stricter than necessary to support
1500          * the currently implemented transformers, but the idea is to
1501          * let transformers to produce diff_filepairs any way they want,
1502          * and filter and clean them up here before producing the output.
1503          */
1504         struct diff_filespec *one, *two;
1505
1506         if (DIFF_PAIR_UNMERGED(p))
1507                 return 0; /* unmerged is interesting */
1508
1509         one = p->one;
1510         two = p->two;
1511
1512         /* deletion, addition, mode or type change
1513          * and rename are all interesting.
1514          */
1515         if (DIFF_FILE_VALID(one) != DIFF_FILE_VALID(two) ||
1516             DIFF_PAIR_MODE_CHANGED(p) ||
1517             strcmp(one->path, two->path))
1518                 return 0;
1519
1520         /* both are valid and point at the same path.  that is, we are
1521          * dealing with a change.
1522          */
1523         if (one->sha1_valid && two->sha1_valid &&
1524             !memcmp(one->sha1, two->sha1, sizeof(one->sha1)))
1525                 return 1; /* no change */
1526         if (!one->sha1_valid && !two->sha1_valid)
1527                 return 1; /* both look at the same file on the filesystem. */
1528         return 0;
1529 }
1530
1531 static void diff_flush_patch(struct diff_filepair *p, struct diff_options *o)
1532 {
1533         if (diff_unmodified_pair(p))
1534                 return;
1535
1536         if ((DIFF_FILE_VALID(p->one) && S_ISDIR(p->one->mode)) ||
1537             (DIFF_FILE_VALID(p->two) && S_ISDIR(p->two->mode)))
1538                 return; /* no tree diffs in patch format */
1539
1540         run_diff(p, o);
1541 }
1542
1543 static void diff_flush_stat(struct diff_filepair *p, struct diff_options *o,
1544                             struct diffstat_t *diffstat)
1545 {
1546         if (diff_unmodified_pair(p))
1547                 return;
1548
1549         if ((DIFF_FILE_VALID(p->one) && S_ISDIR(p->one->mode)) ||
1550             (DIFF_FILE_VALID(p->two) && S_ISDIR(p->two->mode)))
1551                 return; /* no tree diffs in patch format */
1552
1553         run_diffstat(p, o, diffstat);
1554 }
1555
1556 int diff_queue_is_empty(void)
1557 {
1558         struct diff_queue_struct *q = &diff_queued_diff;
1559         int i;
1560         for (i = 0; i < q->nr; i++)
1561                 if (!diff_unmodified_pair(q->queue[i]))
1562                         return 0;
1563         return 1;
1564 }
1565
1566 #if DIFF_DEBUG
1567 void diff_debug_filespec(struct diff_filespec *s, int x, const char *one)
1568 {
1569         fprintf(stderr, "queue[%d] %s (%s) %s %06o %s\n",
1570                 x, one ? one : "",
1571                 s->path,
1572                 DIFF_FILE_VALID(s) ? "valid" : "invalid",
1573                 s->mode,
1574                 s->sha1_valid ? sha1_to_hex(s->sha1) : "");
1575         fprintf(stderr, "queue[%d] %s size %lu flags %d\n",
1576                 x, one ? one : "",
1577                 s->size, s->xfrm_flags);
1578 }
1579
1580 void diff_debug_filepair(const struct diff_filepair *p, int i)
1581 {
1582         diff_debug_filespec(p->one, i, "one");
1583         diff_debug_filespec(p->two, i, "two");
1584         fprintf(stderr, "score %d, status %c stays %d broken %d\n",
1585                 p->score, p->status ? p->status : '?',
1586                 p->source_stays, p->broken_pair);
1587 }
1588
1589 void diff_debug_queue(const char *msg, struct diff_queue_struct *q)
1590 {
1591         int i;
1592         if (msg)
1593                 fprintf(stderr, "%s\n", msg);
1594         fprintf(stderr, "q->nr = %d\n", q->nr);
1595         for (i = 0; i < q->nr; i++) {
1596                 struct diff_filepair *p = q->queue[i];
1597                 diff_debug_filepair(p, i);
1598         }
1599 }
1600 #endif
1601
1602 static void diff_resolve_rename_copy(void)
1603 {
1604         int i, j;
1605         struct diff_filepair *p, *pp;
1606         struct diff_queue_struct *q = &diff_queued_diff;
1607
1608         diff_debug_queue("resolve-rename-copy", q);
1609
1610         for (i = 0; i < q->nr; i++) {
1611                 p = q->queue[i];
1612                 p->status = 0; /* undecided */
1613                 if (DIFF_PAIR_UNMERGED(p))
1614                         p->status = DIFF_STATUS_UNMERGED;
1615                 else if (!DIFF_FILE_VALID(p->one))
1616                         p->status = DIFF_STATUS_ADDED;
1617                 else if (!DIFF_FILE_VALID(p->two))
1618                         p->status = DIFF_STATUS_DELETED;
1619                 else if (DIFF_PAIR_TYPE_CHANGED(p))
1620                         p->status = DIFF_STATUS_TYPE_CHANGED;
1621
1622                 /* from this point on, we are dealing with a pair
1623                  * whose both sides are valid and of the same type, i.e.
1624                  * either in-place edit or rename/copy edit.
1625                  */
1626                 else if (DIFF_PAIR_RENAME(p)) {
1627                         if (p->source_stays) {
1628                                 p->status = DIFF_STATUS_COPIED;
1629                                 continue;
1630                         }
1631                         /* See if there is some other filepair that
1632                          * copies from the same source as us.  If so
1633                          * we are a copy.  Otherwise we are either a
1634                          * copy if the path stays, or a rename if it
1635                          * does not, but we already handled "stays" case.
1636                          */
1637                         for (j = i + 1; j < q->nr; j++) {
1638                                 pp = q->queue[j];
1639                                 if (strcmp(pp->one->path, p->one->path))
1640                                         continue; /* not us */
1641                                 if (!DIFF_PAIR_RENAME(pp))
1642                                         continue; /* not a rename/copy */
1643                                 /* pp is a rename/copy from the same source */
1644                                 p->status = DIFF_STATUS_COPIED;
1645                                 break;
1646                         }
1647                         if (!p->status)
1648                                 p->status = DIFF_STATUS_RENAMED;
1649                 }
1650                 else if (memcmp(p->one->sha1, p->two->sha1, 20) ||
1651                          p->one->mode != p->two->mode)
1652                         p->status = DIFF_STATUS_MODIFIED;
1653                 else {
1654                         /* This is a "no-change" entry and should not
1655                          * happen anymore, but prepare for broken callers.
1656                          */
1657                         error("feeding unmodified %s to diffcore",
1658                               p->one->path);
1659                         p->status = DIFF_STATUS_UNKNOWN;
1660                 }
1661         }
1662         diff_debug_queue("resolve-rename-copy done", q);
1663 }
1664
1665 static void flush_one_pair(struct diff_filepair *p,
1666                            int diff_output_format,
1667                            struct diff_options *options,
1668                            struct diffstat_t *diffstat)
1669 {
1670         int inter_name_termination = '\t';
1671         int line_termination = options->line_termination;
1672         if (!line_termination)
1673                 inter_name_termination = 0;
1674
1675         switch (p->status) {
1676         case DIFF_STATUS_UNKNOWN:
1677                 break;
1678         case 0:
1679                 die("internal error in diff-resolve-rename-copy");
1680                 break;
1681         default:
1682                 switch (diff_output_format) {
1683                 case DIFF_FORMAT_DIFFSTAT:
1684                         diff_flush_stat(p, options, diffstat);
1685                         break;
1686                 case DIFF_FORMAT_PATCH:
1687                         diff_flush_patch(p, options);
1688                         break;
1689                 case DIFF_FORMAT_RAW:
1690                 case DIFF_FORMAT_NAME_STATUS:
1691                         diff_flush_raw(p, line_termination,
1692                                        inter_name_termination,
1693                                        options, diff_output_format);
1694                         break;
1695                 case DIFF_FORMAT_NAME:
1696                         diff_flush_name(p,
1697                                         inter_name_termination,
1698                                         line_termination);
1699                         break;
1700                 case DIFF_FORMAT_NO_OUTPUT:
1701                         break;
1702                 }
1703         }
1704 }
1705
1706 void diff_flush(struct diff_options *options)
1707 {
1708         struct diff_queue_struct *q = &diff_queued_diff;
1709         int i;
1710         int diff_output_format = options->output_format;
1711         struct diffstat_t *diffstat = NULL;
1712
1713         if (diff_output_format == DIFF_FORMAT_DIFFSTAT || options->with_stat) {
1714                 diffstat = xcalloc(sizeof (struct diffstat_t), 1);
1715                 diffstat->xm.consume = diffstat_consume;
1716         }
1717
1718         if (options->with_raw) {
1719                 for (i = 0; i < q->nr; i++) {
1720                         struct diff_filepair *p = q->queue[i];
1721                         flush_one_pair(p, DIFF_FORMAT_RAW, options, NULL);
1722                 }
1723                 putchar(options->line_termination);
1724         }
1725         if (options->with_stat) {
1726                 for (i = 0; i < q->nr; i++) {
1727                         struct diff_filepair *p = q->queue[i];
1728                         flush_one_pair(p, DIFF_FORMAT_DIFFSTAT, options,
1729                                        diffstat);
1730                 }
1731                 show_stats(diffstat);
1732                 free(diffstat);
1733                 diffstat = NULL;
1734                 putchar(options->line_termination);
1735         }
1736         for (i = 0; i < q->nr; i++) {
1737                 struct diff_filepair *p = q->queue[i];
1738                 flush_one_pair(p, diff_output_format, options, diffstat);
1739                 diff_free_filepair(p);
1740         }
1741
1742         if (diffstat) {
1743                 show_stats(diffstat);
1744                 free(diffstat);
1745         }
1746
1747         free(q->queue);
1748         q->queue = NULL;
1749         q->nr = q->alloc = 0;
1750 }
1751
1752 static void diffcore_apply_filter(const char *filter)
1753 {
1754         int i;
1755         struct diff_queue_struct *q = &diff_queued_diff;
1756         struct diff_queue_struct outq;
1757         outq.queue = NULL;
1758         outq.nr = outq.alloc = 0;
1759
1760         if (!filter)
1761                 return;
1762
1763         if (strchr(filter, DIFF_STATUS_FILTER_AON)) {
1764                 int found;
1765                 for (i = found = 0; !found && i < q->nr; i++) {
1766                         struct diff_filepair *p = q->queue[i];
1767                         if (((p->status == DIFF_STATUS_MODIFIED) &&
1768                              ((p->score &&
1769                                strchr(filter, DIFF_STATUS_FILTER_BROKEN)) ||
1770                               (!p->score &&
1771                                strchr(filter, DIFF_STATUS_MODIFIED)))) ||
1772                             ((p->status != DIFF_STATUS_MODIFIED) &&
1773                              strchr(filter, p->status)))
1774                                 found++;
1775                 }
1776                 if (found)
1777                         return;
1778
1779                 /* otherwise we will clear the whole queue
1780                  * by copying the empty outq at the end of this
1781                  * function, but first clear the current entries
1782                  * in the queue.
1783                  */
1784                 for (i = 0; i < q->nr; i++)
1785                         diff_free_filepair(q->queue[i]);
1786         }
1787         else {
1788                 /* Only the matching ones */
1789                 for (i = 0; i < q->nr; i++) {
1790                         struct diff_filepair *p = q->queue[i];
1791
1792                         if (((p->status == DIFF_STATUS_MODIFIED) &&
1793                              ((p->score &&
1794                                strchr(filter, DIFF_STATUS_FILTER_BROKEN)) ||
1795                               (!p->score &&
1796                                strchr(filter, DIFF_STATUS_MODIFIED)))) ||
1797                             ((p->status != DIFF_STATUS_MODIFIED) &&
1798                              strchr(filter, p->status)))
1799                                 diff_q(&outq, p);
1800                         else
1801                                 diff_free_filepair(p);
1802                 }
1803         }
1804         free(q->queue);
1805         *q = outq;
1806 }
1807
1808 void diffcore_std(struct diff_options *options)
1809 {
1810         if (options->break_opt != -1)
1811                 diffcore_break(options->break_opt);
1812         if (options->detect_rename)
1813                 diffcore_rename(options);
1814         if (options->break_opt != -1)
1815                 diffcore_merge_broken();
1816         if (options->pickaxe)
1817                 diffcore_pickaxe(options->pickaxe, options->pickaxe_opts);
1818         if (options->orderfile)
1819                 diffcore_order(options->orderfile);
1820         diff_resolve_rename_copy();
1821         diffcore_apply_filter(options->filter);
1822 }
1823
1824
1825 void diffcore_std_no_resolve(struct diff_options *options)
1826 {
1827         if (options->pickaxe)
1828                 diffcore_pickaxe(options->pickaxe, options->pickaxe_opts);
1829         if (options->orderfile)
1830                 diffcore_order(options->orderfile);
1831         diffcore_apply_filter(options->filter);
1832 }
1833
1834 void diff_addremove(struct diff_options *options,
1835                     int addremove, unsigned mode,
1836                     const unsigned char *sha1,
1837                     const char *base, const char *path)
1838 {
1839         char concatpath[PATH_MAX];
1840         struct diff_filespec *one, *two;
1841
1842         /* This may look odd, but it is a preparation for
1843          * feeding "there are unchanged files which should
1844          * not produce diffs, but when you are doing copy
1845          * detection you would need them, so here they are"
1846          * entries to the diff-core.  They will be prefixed
1847          * with something like '=' or '*' (I haven't decided
1848          * which but should not make any difference).
1849          * Feeding the same new and old to diff_change() 
1850          * also has the same effect.
1851          * Before the final output happens, they are pruned after
1852          * merged into rename/copy pairs as appropriate.
1853          */
1854         if (options->reverse_diff)
1855                 addremove = (addremove == '+' ? '-' :
1856                              addremove == '-' ? '+' : addremove);
1857
1858         if (!path) path = "";
1859         sprintf(concatpath, "%s%s", base, path);
1860         one = alloc_filespec(concatpath);
1861         two = alloc_filespec(concatpath);
1862
1863         if (addremove != '+')
1864                 fill_filespec(one, sha1, mode);
1865         if (addremove != '-')
1866                 fill_filespec(two, sha1, mode);
1867
1868         diff_queue(&diff_queued_diff, one, two);
1869 }
1870
1871 void diff_change(struct diff_options *options,
1872                  unsigned old_mode, unsigned new_mode,
1873                  const unsigned char *old_sha1,
1874                  const unsigned char *new_sha1,
1875                  const char *base, const char *path) 
1876 {
1877         char concatpath[PATH_MAX];
1878         struct diff_filespec *one, *two;
1879
1880         if (options->reverse_diff) {
1881                 unsigned tmp;
1882                 const unsigned char *tmp_c;
1883                 tmp = old_mode; old_mode = new_mode; new_mode = tmp;
1884                 tmp_c = old_sha1; old_sha1 = new_sha1; new_sha1 = tmp_c;
1885         }
1886         if (!path) path = "";
1887         sprintf(concatpath, "%s%s", base, path);
1888         one = alloc_filespec(concatpath);
1889         two = alloc_filespec(concatpath);
1890         fill_filespec(one, old_sha1, old_mode);
1891         fill_filespec(two, new_sha1, new_mode);
1892
1893         diff_queue(&diff_queued_diff, one, two);
1894 }
1895
1896 void diff_unmerge(struct diff_options *options,
1897                   const char *path)
1898 {
1899         struct diff_filespec *one, *two;
1900         one = alloc_filespec(path);
1901         two = alloc_filespec(path);
1902         diff_queue(&diff_queued_diff, one, two);
1903 }