Merge git://repo.or.cz/git-gui
[git] / diff.c
1 /*
2  * Copyright (C) 2005 Junio C Hamano
3  */
4 #include "cache.h"
5 #include "quote.h"
6 #include "diff.h"
7 #include "diffcore.h"
8 #include "delta.h"
9 #include "xdiff-interface.h"
10 #include "color.h"
11 #include "attr.h"
12 #include "run-command.h"
13 #include "utf8.h"
14 #include "userdiff.h"
15
16 #ifdef NO_FAST_WORKING_DIRECTORY
17 #define FAST_WORKING_DIRECTORY 0
18 #else
19 #define FAST_WORKING_DIRECTORY 1
20 #endif
21
22 static int diff_detect_rename_default;
23 static int diff_rename_limit_default = 200;
24 static int diff_suppress_blank_empty;
25 int diff_use_color_default = -1;
26 static const char *external_diff_cmd_cfg;
27 int diff_auto_refresh_index = 1;
28 static int diff_mnemonic_prefix;
29
30 static char diff_colors[][COLOR_MAXLEN] = {
31         "\033[m",       /* reset */
32         "",             /* PLAIN (normal) */
33         "\033[1m",      /* METAINFO (bold) */
34         "\033[36m",     /* FRAGINFO (cyan) */
35         "\033[31m",     /* OLD (red) */
36         "\033[32m",     /* NEW (green) */
37         "\033[33m",     /* COMMIT (yellow) */
38         "\033[41m",     /* WHITESPACE (red background) */
39 };
40
41 static void diff_filespec_load_driver(struct diff_filespec *one);
42 static char *run_textconv(const char *, struct diff_filespec *, size_t *);
43
44 static int parse_diff_color_slot(const char *var, int ofs)
45 {
46         if (!strcasecmp(var+ofs, "plain"))
47                 return DIFF_PLAIN;
48         if (!strcasecmp(var+ofs, "meta"))
49                 return DIFF_METAINFO;
50         if (!strcasecmp(var+ofs, "frag"))
51                 return DIFF_FRAGINFO;
52         if (!strcasecmp(var+ofs, "old"))
53                 return DIFF_FILE_OLD;
54         if (!strcasecmp(var+ofs, "new"))
55                 return DIFF_FILE_NEW;
56         if (!strcasecmp(var+ofs, "commit"))
57                 return DIFF_COMMIT;
58         if (!strcasecmp(var+ofs, "whitespace"))
59                 return DIFF_WHITESPACE;
60         die("bad config variable '%s'", var);
61 }
62
63 /*
64  * These are to give UI layer defaults.
65  * The core-level commands such as git-diff-files should
66  * never be affected by the setting of diff.renames
67  * the user happens to have in the configuration file.
68  */
69 int git_diff_ui_config(const char *var, const char *value, void *cb)
70 {
71         if (!strcmp(var, "diff.color") || !strcmp(var, "color.diff")) {
72                 diff_use_color_default = git_config_colorbool(var, value, -1);
73                 return 0;
74         }
75         if (!strcmp(var, "diff.renames")) {
76                 if (!value)
77                         diff_detect_rename_default = DIFF_DETECT_RENAME;
78                 else if (!strcasecmp(value, "copies") ||
79                          !strcasecmp(value, "copy"))
80                         diff_detect_rename_default = DIFF_DETECT_COPY;
81                 else if (git_config_bool(var,value))
82                         diff_detect_rename_default = DIFF_DETECT_RENAME;
83                 return 0;
84         }
85         if (!strcmp(var, "diff.autorefreshindex")) {
86                 diff_auto_refresh_index = git_config_bool(var, value);
87                 return 0;
88         }
89         if (!strcmp(var, "diff.mnemonicprefix")) {
90                 diff_mnemonic_prefix = git_config_bool(var, value);
91                 return 0;
92         }
93         if (!strcmp(var, "diff.external"))
94                 return git_config_string(&external_diff_cmd_cfg, var, value);
95
96         return git_diff_basic_config(var, value, cb);
97 }
98
99 int git_diff_basic_config(const char *var, const char *value, void *cb)
100 {
101         if (!strcmp(var, "diff.renamelimit")) {
102                 diff_rename_limit_default = git_config_int(var, value);
103                 return 0;
104         }
105
106         switch (userdiff_config(var, value)) {
107                 case 0: break;
108                 case -1: return -1;
109                 default: return 0;
110         }
111
112         if (!prefixcmp(var, "diff.color.") || !prefixcmp(var, "color.diff.")) {
113                 int slot = parse_diff_color_slot(var, 11);
114                 if (!value)
115                         return config_error_nonbool(var);
116                 color_parse(value, var, diff_colors[slot]);
117                 return 0;
118         }
119
120         /* like GNU diff's --suppress-blank-empty option  */
121         if (!strcmp(var, "diff.suppress-blank-empty")) {
122                 diff_suppress_blank_empty = git_config_bool(var, value);
123                 return 0;
124         }
125
126         return git_color_default_config(var, value, cb);
127 }
128
129 static char *quote_two(const char *one, const char *two)
130 {
131         int need_one = quote_c_style(one, NULL, NULL, 1);
132         int need_two = quote_c_style(two, NULL, NULL, 1);
133         struct strbuf res = STRBUF_INIT;
134
135         if (need_one + need_two) {
136                 strbuf_addch(&res, '"');
137                 quote_c_style(one, &res, NULL, 1);
138                 quote_c_style(two, &res, NULL, 1);
139                 strbuf_addch(&res, '"');
140         } else {
141                 strbuf_addstr(&res, one);
142                 strbuf_addstr(&res, two);
143         }
144         return strbuf_detach(&res, NULL);
145 }
146
147 static const char *external_diff(void)
148 {
149         static const char *external_diff_cmd = NULL;
150         static int done_preparing = 0;
151
152         if (done_preparing)
153                 return external_diff_cmd;
154         external_diff_cmd = getenv("GIT_EXTERNAL_DIFF");
155         if (!external_diff_cmd)
156                 external_diff_cmd = external_diff_cmd_cfg;
157         done_preparing = 1;
158         return external_diff_cmd;
159 }
160
161 static struct diff_tempfile {
162         const char *name; /* filename external diff should read from */
163         char hex[41];
164         char mode[10];
165         char tmp_path[PATH_MAX];
166 } diff_temp[2];
167
168 static int count_lines(const char *data, int size)
169 {
170         int count, ch, completely_empty = 1, nl_just_seen = 0;
171         count = 0;
172         while (0 < size--) {
173                 ch = *data++;
174                 if (ch == '\n') {
175                         count++;
176                         nl_just_seen = 1;
177                         completely_empty = 0;
178                 }
179                 else {
180                         nl_just_seen = 0;
181                         completely_empty = 0;
182                 }
183         }
184         if (completely_empty)
185                 return 0;
186         if (!nl_just_seen)
187                 count++; /* no trailing newline */
188         return count;
189 }
190
191 static void print_line_count(FILE *file, int count)
192 {
193         switch (count) {
194         case 0:
195                 fprintf(file, "0,0");
196                 break;
197         case 1:
198                 fprintf(file, "1");
199                 break;
200         default:
201                 fprintf(file, "1,%d", count);
202                 break;
203         }
204 }
205
206 static void copy_file_with_prefix(FILE *file,
207                                   int prefix, const char *data, int size,
208                                   const char *set, const char *reset)
209 {
210         int ch, nl_just_seen = 1;
211         while (0 < size--) {
212                 ch = *data++;
213                 if (nl_just_seen) {
214                         fputs(set, file);
215                         putc(prefix, file);
216                 }
217                 if (ch == '\n') {
218                         nl_just_seen = 1;
219                         fputs(reset, file);
220                 } else
221                         nl_just_seen = 0;
222                 putc(ch, file);
223         }
224         if (!nl_just_seen)
225                 fprintf(file, "%s\n\\ No newline at end of file\n", reset);
226 }
227
228 static void emit_rewrite_diff(const char *name_a,
229                               const char *name_b,
230                               struct diff_filespec *one,
231                               struct diff_filespec *two,
232                               struct diff_options *o)
233 {
234         int lc_a, lc_b;
235         int color_diff = DIFF_OPT_TST(o, COLOR_DIFF);
236         const char *name_a_tab, *name_b_tab;
237         const char *metainfo = diff_get_color(color_diff, DIFF_METAINFO);
238         const char *fraginfo = diff_get_color(color_diff, DIFF_FRAGINFO);
239         const char *old = diff_get_color(color_diff, DIFF_FILE_OLD);
240         const char *new = diff_get_color(color_diff, DIFF_FILE_NEW);
241         const char *reset = diff_get_color(color_diff, DIFF_RESET);
242         static struct strbuf a_name = STRBUF_INIT, b_name = STRBUF_INIT;
243         const char *a_prefix, *b_prefix;
244
245         if (diff_mnemonic_prefix && DIFF_OPT_TST(o, REVERSE_DIFF)) {
246                 a_prefix = o->b_prefix;
247                 b_prefix = o->a_prefix;
248         } else {
249                 a_prefix = o->a_prefix;
250                 b_prefix = o->b_prefix;
251         }
252
253         name_a += (*name_a == '/');
254         name_b += (*name_b == '/');
255         name_a_tab = strchr(name_a, ' ') ? "\t" : "";
256         name_b_tab = strchr(name_b, ' ') ? "\t" : "";
257
258         strbuf_reset(&a_name);
259         strbuf_reset(&b_name);
260         quote_two_c_style(&a_name, a_prefix, name_a, 0);
261         quote_two_c_style(&b_name, b_prefix, name_b, 0);
262
263         diff_populate_filespec(one, 0);
264         diff_populate_filespec(two, 0);
265         lc_a = count_lines(one->data, one->size);
266         lc_b = count_lines(two->data, two->size);
267         fprintf(o->file,
268                 "%s--- %s%s%s\n%s+++ %s%s%s\n%s@@ -",
269                 metainfo, a_name.buf, name_a_tab, reset,
270                 metainfo, b_name.buf, name_b_tab, reset, fraginfo);
271         print_line_count(o->file, lc_a);
272         fprintf(o->file, " +");
273         print_line_count(o->file, lc_b);
274         fprintf(o->file, " @@%s\n", reset);
275         if (lc_a)
276                 copy_file_with_prefix(o->file, '-', one->data, one->size, old, reset);
277         if (lc_b)
278                 copy_file_with_prefix(o->file, '+', two->data, two->size, new, reset);
279 }
280
281 static int fill_mmfile(mmfile_t *mf, struct diff_filespec *one)
282 {
283         if (!DIFF_FILE_VALID(one)) {
284                 mf->ptr = (char *)""; /* does not matter */
285                 mf->size = 0;
286                 return 0;
287         }
288         else if (diff_populate_filespec(one, 0))
289                 return -1;
290
291         mf->ptr = one->data;
292         mf->size = one->size;
293         return 0;
294 }
295
296 struct diff_words_buffer {
297         mmfile_t text;
298         long alloc;
299         long current; /* output pointer */
300         int suppressed_newline;
301 };
302
303 static void diff_words_append(char *line, unsigned long len,
304                 struct diff_words_buffer *buffer)
305 {
306         if (buffer->text.size + len > buffer->alloc) {
307                 buffer->alloc = (buffer->text.size + len) * 3 / 2;
308                 buffer->text.ptr = xrealloc(buffer->text.ptr, buffer->alloc);
309         }
310         line++;
311         len--;
312         memcpy(buffer->text.ptr + buffer->text.size, line, len);
313         buffer->text.size += len;
314 }
315
316 struct diff_words_data {
317         struct diff_words_buffer minus, plus;
318         FILE *file;
319 };
320
321 static void print_word(FILE *file, struct diff_words_buffer *buffer, int len, int color,
322                 int suppress_newline)
323 {
324         const char *ptr;
325         int eol = 0;
326
327         if (len == 0)
328                 return;
329
330         ptr  = buffer->text.ptr + buffer->current;
331         buffer->current += len;
332
333         if (ptr[len - 1] == '\n') {
334                 eol = 1;
335                 len--;
336         }
337
338         fputs(diff_get_color(1, color), file);
339         fwrite(ptr, len, 1, file);
340         fputs(diff_get_color(1, DIFF_RESET), file);
341
342         if (eol) {
343                 if (suppress_newline)
344                         buffer->suppressed_newline = 1;
345                 else
346                         putc('\n', file);
347         }
348 }
349
350 static void fn_out_diff_words_aux(void *priv, char *line, unsigned long len)
351 {
352         struct diff_words_data *diff_words = priv;
353
354         if (diff_words->minus.suppressed_newline) {
355                 if (line[0] != '+')
356                         putc('\n', diff_words->file);
357                 diff_words->minus.suppressed_newline = 0;
358         }
359
360         len--;
361         switch (line[0]) {
362                 case '-':
363                         print_word(diff_words->file,
364                                    &diff_words->minus, len, DIFF_FILE_OLD, 1);
365                         break;
366                 case '+':
367                         print_word(diff_words->file,
368                                    &diff_words->plus, len, DIFF_FILE_NEW, 0);
369                         break;
370                 case ' ':
371                         print_word(diff_words->file,
372                                    &diff_words->plus, len, DIFF_PLAIN, 0);
373                         diff_words->minus.current += len;
374                         break;
375         }
376 }
377
378 /* this executes the word diff on the accumulated buffers */
379 static void diff_words_show(struct diff_words_data *diff_words)
380 {
381         xpparam_t xpp;
382         xdemitconf_t xecfg;
383         xdemitcb_t ecb;
384         mmfile_t minus, plus;
385         int i;
386
387         memset(&xpp, 0, sizeof(xpp));
388         memset(&xecfg, 0, sizeof(xecfg));
389         minus.size = diff_words->minus.text.size;
390         minus.ptr = xmalloc(minus.size);
391         memcpy(minus.ptr, diff_words->minus.text.ptr, minus.size);
392         for (i = 0; i < minus.size; i++)
393                 if (isspace(minus.ptr[i]))
394                         minus.ptr[i] = '\n';
395         diff_words->minus.current = 0;
396
397         plus.size = diff_words->plus.text.size;
398         plus.ptr = xmalloc(plus.size);
399         memcpy(plus.ptr, diff_words->plus.text.ptr, plus.size);
400         for (i = 0; i < plus.size; i++)
401                 if (isspace(plus.ptr[i]))
402                         plus.ptr[i] = '\n';
403         diff_words->plus.current = 0;
404
405         xpp.flags = XDF_NEED_MINIMAL;
406         xecfg.ctxlen = diff_words->minus.alloc + diff_words->plus.alloc;
407         xdi_diff_outf(&minus, &plus, fn_out_diff_words_aux, diff_words,
408                       &xpp, &xecfg, &ecb);
409         free(minus.ptr);
410         free(plus.ptr);
411         diff_words->minus.text.size = diff_words->plus.text.size = 0;
412
413         if (diff_words->minus.suppressed_newline) {
414                 putc('\n', diff_words->file);
415                 diff_words->minus.suppressed_newline = 0;
416         }
417 }
418
419 typedef unsigned long (*sane_truncate_fn)(char *line, unsigned long len);
420
421 struct emit_callback {
422         int nparents, color_diff;
423         unsigned ws_rule;
424         sane_truncate_fn truncate;
425         const char **label_path;
426         struct diff_words_data *diff_words;
427         int *found_changesp;
428         FILE *file;
429 };
430
431 static void free_diff_words_data(struct emit_callback *ecbdata)
432 {
433         if (ecbdata->diff_words) {
434                 /* flush buffers */
435                 if (ecbdata->diff_words->minus.text.size ||
436                                 ecbdata->diff_words->plus.text.size)
437                         diff_words_show(ecbdata->diff_words);
438
439                 free (ecbdata->diff_words->minus.text.ptr);
440                 free (ecbdata->diff_words->plus.text.ptr);
441                 free(ecbdata->diff_words);
442                 ecbdata->diff_words = NULL;
443         }
444 }
445
446 const char *diff_get_color(int diff_use_color, enum color_diff ix)
447 {
448         if (diff_use_color)
449                 return diff_colors[ix];
450         return "";
451 }
452
453 static void emit_line(FILE *file, const char *set, const char *reset, const char *line, int len)
454 {
455         int has_trailing_newline, has_trailing_carriage_return;
456
457         has_trailing_newline = (len > 0 && line[len-1] == '\n');
458         if (has_trailing_newline)
459                 len--;
460         has_trailing_carriage_return = (len > 0 && line[len-1] == '\r');
461         if (has_trailing_carriage_return)
462                 len--;
463
464         fputs(set, file);
465         fwrite(line, len, 1, file);
466         fputs(reset, file);
467         if (has_trailing_carriage_return)
468                 fputc('\r', file);
469         if (has_trailing_newline)
470                 fputc('\n', file);
471 }
472
473 static void emit_add_line(const char *reset, struct emit_callback *ecbdata, const char *line, int len)
474 {
475         const char *ws = diff_get_color(ecbdata->color_diff, DIFF_WHITESPACE);
476         const char *set = diff_get_color(ecbdata->color_diff, DIFF_FILE_NEW);
477
478         if (!*ws)
479                 emit_line(ecbdata->file, set, reset, line, len);
480         else {
481                 /* Emit just the prefix, then the rest. */
482                 emit_line(ecbdata->file, set, reset, line, ecbdata->nparents);
483                 ws_check_emit(line + ecbdata->nparents,
484                               len - ecbdata->nparents, ecbdata->ws_rule,
485                               ecbdata->file, set, reset, ws);
486         }
487 }
488
489 static unsigned long sane_truncate_line(struct emit_callback *ecb, char *line, unsigned long len)
490 {
491         const char *cp;
492         unsigned long allot;
493         size_t l = len;
494
495         if (ecb->truncate)
496                 return ecb->truncate(line, len);
497         cp = line;
498         allot = l;
499         while (0 < l) {
500                 (void) utf8_width(&cp, &l);
501                 if (!cp)
502                         break; /* truncated in the middle? */
503         }
504         return allot - l;
505 }
506
507 static void fn_out_consume(void *priv, char *line, unsigned long len)
508 {
509         int i;
510         int color;
511         struct emit_callback *ecbdata = priv;
512         const char *meta = diff_get_color(ecbdata->color_diff, DIFF_METAINFO);
513         const char *plain = diff_get_color(ecbdata->color_diff, DIFF_PLAIN);
514         const char *reset = diff_get_color(ecbdata->color_diff, DIFF_RESET);
515
516         *(ecbdata->found_changesp) = 1;
517
518         if (ecbdata->label_path[0]) {
519                 const char *name_a_tab, *name_b_tab;
520
521                 name_a_tab = strchr(ecbdata->label_path[0], ' ') ? "\t" : "";
522                 name_b_tab = strchr(ecbdata->label_path[1], ' ') ? "\t" : "";
523
524                 fprintf(ecbdata->file, "%s--- %s%s%s\n",
525                         meta, ecbdata->label_path[0], reset, name_a_tab);
526                 fprintf(ecbdata->file, "%s+++ %s%s%s\n",
527                         meta, ecbdata->label_path[1], reset, name_b_tab);
528                 ecbdata->label_path[0] = ecbdata->label_path[1] = NULL;
529         }
530
531         if (diff_suppress_blank_empty
532             && len == 2 && line[0] == ' ' && line[1] == '\n') {
533                 line[0] = '\n';
534                 len = 1;
535         }
536
537         /* This is not really necessary for now because
538          * this codepath only deals with two-way diffs.
539          */
540         for (i = 0; i < len && line[i] == '@'; i++)
541                 ;
542         if (2 <= i && i < len && line[i] == ' ') {
543                 ecbdata->nparents = i - 1;
544                 len = sane_truncate_line(ecbdata, line, len);
545                 emit_line(ecbdata->file,
546                           diff_get_color(ecbdata->color_diff, DIFF_FRAGINFO),
547                           reset, line, len);
548                 if (line[len-1] != '\n')
549                         putc('\n', ecbdata->file);
550                 return;
551         }
552
553         if (len < ecbdata->nparents) {
554                 emit_line(ecbdata->file, reset, reset, line, len);
555                 return;
556         }
557
558         color = DIFF_PLAIN;
559         if (ecbdata->diff_words && ecbdata->nparents != 1)
560                 /* fall back to normal diff */
561                 free_diff_words_data(ecbdata);
562         if (ecbdata->diff_words) {
563                 if (line[0] == '-') {
564                         diff_words_append(line, len,
565                                           &ecbdata->diff_words->minus);
566                         return;
567                 } else if (line[0] == '+') {
568                         diff_words_append(line, len,
569                                           &ecbdata->diff_words->plus);
570                         return;
571                 }
572                 if (ecbdata->diff_words->minus.text.size ||
573                     ecbdata->diff_words->plus.text.size)
574                         diff_words_show(ecbdata->diff_words);
575                 line++;
576                 len--;
577                 emit_line(ecbdata->file, plain, reset, line, len);
578                 return;
579         }
580         for (i = 0; i < ecbdata->nparents && len; i++) {
581                 if (line[i] == '-')
582                         color = DIFF_FILE_OLD;
583                 else if (line[i] == '+')
584                         color = DIFF_FILE_NEW;
585         }
586
587         if (color != DIFF_FILE_NEW) {
588                 emit_line(ecbdata->file,
589                           diff_get_color(ecbdata->color_diff, color),
590                           reset, line, len);
591                 return;
592         }
593         emit_add_line(reset, ecbdata, line, len);
594 }
595
596 static char *pprint_rename(const char *a, const char *b)
597 {
598         const char *old = a;
599         const char *new = b;
600         struct strbuf name = STRBUF_INIT;
601         int pfx_length, sfx_length;
602         int len_a = strlen(a);
603         int len_b = strlen(b);
604         int a_midlen, b_midlen;
605         int qlen_a = quote_c_style(a, NULL, NULL, 0);
606         int qlen_b = quote_c_style(b, NULL, NULL, 0);
607
608         if (qlen_a || qlen_b) {
609                 quote_c_style(a, &name, NULL, 0);
610                 strbuf_addstr(&name, " => ");
611                 quote_c_style(b, &name, NULL, 0);
612                 return strbuf_detach(&name, NULL);
613         }
614
615         /* Find common prefix */
616         pfx_length = 0;
617         while (*old && *new && *old == *new) {
618                 if (*old == '/')
619                         pfx_length = old - a + 1;
620                 old++;
621                 new++;
622         }
623
624         /* Find common suffix */
625         old = a + len_a;
626         new = b + len_b;
627         sfx_length = 0;
628         while (a <= old && b <= new && *old == *new) {
629                 if (*old == '/')
630                         sfx_length = len_a - (old - a);
631                 old--;
632                 new--;
633         }
634
635         /*
636          * pfx{mid-a => mid-b}sfx
637          * {pfx-a => pfx-b}sfx
638          * pfx{sfx-a => sfx-b}
639          * name-a => name-b
640          */
641         a_midlen = len_a - pfx_length - sfx_length;
642         b_midlen = len_b - pfx_length - sfx_length;
643         if (a_midlen < 0)
644                 a_midlen = 0;
645         if (b_midlen < 0)
646                 b_midlen = 0;
647
648         strbuf_grow(&name, pfx_length + a_midlen + b_midlen + sfx_length + 7);
649         if (pfx_length + sfx_length) {
650                 strbuf_add(&name, a, pfx_length);
651                 strbuf_addch(&name, '{');
652         }
653         strbuf_add(&name, a + pfx_length, a_midlen);
654         strbuf_addstr(&name, " => ");
655         strbuf_add(&name, b + pfx_length, b_midlen);
656         if (pfx_length + sfx_length) {
657                 strbuf_addch(&name, '}');
658                 strbuf_add(&name, a + len_a - sfx_length, sfx_length);
659         }
660         return strbuf_detach(&name, NULL);
661 }
662
663 struct diffstat_t {
664         int nr;
665         int alloc;
666         struct diffstat_file {
667                 char *from_name;
668                 char *name;
669                 char *print_name;
670                 unsigned is_unmerged:1;
671                 unsigned is_binary:1;
672                 unsigned is_renamed:1;
673                 unsigned int added, deleted;
674         } **files;
675 };
676
677 static struct diffstat_file *diffstat_add(struct diffstat_t *diffstat,
678                                           const char *name_a,
679                                           const char *name_b)
680 {
681         struct diffstat_file *x;
682         x = xcalloc(sizeof (*x), 1);
683         if (diffstat->nr == diffstat->alloc) {
684                 diffstat->alloc = alloc_nr(diffstat->alloc);
685                 diffstat->files = xrealloc(diffstat->files,
686                                 diffstat->alloc * sizeof(x));
687         }
688         diffstat->files[diffstat->nr++] = x;
689         if (name_b) {
690                 x->from_name = xstrdup(name_a);
691                 x->name = xstrdup(name_b);
692                 x->is_renamed = 1;
693         }
694         else {
695                 x->from_name = NULL;
696                 x->name = xstrdup(name_a);
697         }
698         return x;
699 }
700
701 static void diffstat_consume(void *priv, char *line, unsigned long len)
702 {
703         struct diffstat_t *diffstat = priv;
704         struct diffstat_file *x = diffstat->files[diffstat->nr - 1];
705
706         if (line[0] == '+')
707                 x->added++;
708         else if (line[0] == '-')
709                 x->deleted++;
710 }
711
712 const char mime_boundary_leader[] = "------------";
713
714 static int scale_linear(int it, int width, int max_change)
715 {
716         /*
717          * make sure that at least one '-' is printed if there were deletions,
718          * and likewise for '+'.
719          */
720         if (max_change < 2)
721                 return it;
722         return ((it - 1) * (width - 1) + max_change - 1) / (max_change - 1);
723 }
724
725 static void show_name(FILE *file,
726                       const char *prefix, const char *name, int len,
727                       const char *reset, const char *set)
728 {
729         fprintf(file, " %s%s%-*s%s |", set, prefix, len, name, reset);
730 }
731
732 static void show_graph(FILE *file, char ch, int cnt, const char *set, const char *reset)
733 {
734         if (cnt <= 0)
735                 return;
736         fprintf(file, "%s", set);
737         while (cnt--)
738                 putc(ch, file);
739         fprintf(file, "%s", reset);
740 }
741
742 static void fill_print_name(struct diffstat_file *file)
743 {
744         char *pname;
745
746         if (file->print_name)
747                 return;
748
749         if (!file->is_renamed) {
750                 struct strbuf buf = STRBUF_INIT;
751                 if (quote_c_style(file->name, &buf, NULL, 0)) {
752                         pname = strbuf_detach(&buf, NULL);
753                 } else {
754                         pname = file->name;
755                         strbuf_release(&buf);
756                 }
757         } else {
758                 pname = pprint_rename(file->from_name, file->name);
759         }
760         file->print_name = pname;
761 }
762
763 static void show_stats(struct diffstat_t* data, struct diff_options *options)
764 {
765         int i, len, add, del, total, adds = 0, dels = 0;
766         int max_change = 0, max_len = 0;
767         int total_files = data->nr;
768         int width, name_width;
769         const char *reset, *set, *add_c, *del_c;
770
771         if (data->nr == 0)
772                 return;
773
774         width = options->stat_width ? options->stat_width : 80;
775         name_width = options->stat_name_width ? options->stat_name_width : 50;
776
777         /* Sanity: give at least 5 columns to the graph,
778          * but leave at least 10 columns for the name.
779          */
780         if (width < 25)
781                 width = 25;
782         if (name_width < 10)
783                 name_width = 10;
784         else if (width < name_width + 15)
785                 name_width = width - 15;
786
787         /* Find the longest filename and max number of changes */
788         reset = diff_get_color_opt(options, DIFF_RESET);
789         set   = diff_get_color_opt(options, DIFF_PLAIN);
790         add_c = diff_get_color_opt(options, DIFF_FILE_NEW);
791         del_c = diff_get_color_opt(options, DIFF_FILE_OLD);
792
793         for (i = 0; i < data->nr; i++) {
794                 struct diffstat_file *file = data->files[i];
795                 int change = file->added + file->deleted;
796                 fill_print_name(file);
797                 len = strlen(file->print_name);
798                 if (max_len < len)
799                         max_len = len;
800
801                 if (file->is_binary || file->is_unmerged)
802                         continue;
803                 if (max_change < change)
804                         max_change = change;
805         }
806
807         /* Compute the width of the graph part;
808          * 10 is for one blank at the beginning of the line plus
809          * " | count " between the name and the graph.
810          *
811          * From here on, name_width is the width of the name area,
812          * and width is the width of the graph area.
813          */
814         name_width = (name_width < max_len) ? name_width : max_len;
815         if (width < (name_width + 10) + max_change)
816                 width = width - (name_width + 10);
817         else
818                 width = max_change;
819
820         for (i = 0; i < data->nr; i++) {
821                 const char *prefix = "";
822                 char *name = data->files[i]->print_name;
823                 int added = data->files[i]->added;
824                 int deleted = data->files[i]->deleted;
825                 int name_len;
826
827                 /*
828                  * "scale" the filename
829                  */
830                 len = name_width;
831                 name_len = strlen(name);
832                 if (name_width < name_len) {
833                         char *slash;
834                         prefix = "...";
835                         len -= 3;
836                         name += name_len - len;
837                         slash = strchr(name, '/');
838                         if (slash)
839                                 name = slash;
840                 }
841
842                 if (data->files[i]->is_binary) {
843                         show_name(options->file, prefix, name, len, reset, set);
844                         fprintf(options->file, "  Bin ");
845                         fprintf(options->file, "%s%d%s", del_c, deleted, reset);
846                         fprintf(options->file, " -> ");
847                         fprintf(options->file, "%s%d%s", add_c, added, reset);
848                         fprintf(options->file, " bytes");
849                         fprintf(options->file, "\n");
850                         continue;
851                 }
852                 else if (data->files[i]->is_unmerged) {
853                         show_name(options->file, prefix, name, len, reset, set);
854                         fprintf(options->file, "  Unmerged\n");
855                         continue;
856                 }
857                 else if (!data->files[i]->is_renamed &&
858                          (added + deleted == 0)) {
859                         total_files--;
860                         continue;
861                 }
862
863                 /*
864                  * scale the add/delete
865                  */
866                 add = added;
867                 del = deleted;
868                 total = add + del;
869                 adds += add;
870                 dels += del;
871
872                 if (width <= max_change) {
873                         add = scale_linear(add, width, max_change);
874                         del = scale_linear(del, width, max_change);
875                         total = add + del;
876                 }
877                 show_name(options->file, prefix, name, len, reset, set);
878                 fprintf(options->file, "%5d%s", added + deleted,
879                                 added + deleted ? " " : "");
880                 show_graph(options->file, '+', add, add_c, reset);
881                 show_graph(options->file, '-', del, del_c, reset);
882                 fprintf(options->file, "\n");
883         }
884         fprintf(options->file,
885                "%s %d files changed, %d insertions(+), %d deletions(-)%s\n",
886                set, total_files, adds, dels, reset);
887 }
888
889 static void show_shortstats(struct diffstat_t* data, struct diff_options *options)
890 {
891         int i, adds = 0, dels = 0, total_files = data->nr;
892
893         if (data->nr == 0)
894                 return;
895
896         for (i = 0; i < data->nr; i++) {
897                 if (!data->files[i]->is_binary &&
898                     !data->files[i]->is_unmerged) {
899                         int added = data->files[i]->added;
900                         int deleted= data->files[i]->deleted;
901                         if (!data->files[i]->is_renamed &&
902                             (added + deleted == 0)) {
903                                 total_files--;
904                         } else {
905                                 adds += added;
906                                 dels += deleted;
907                         }
908                 }
909         }
910         fprintf(options->file, " %d files changed, %d insertions(+), %d deletions(-)\n",
911                total_files, adds, dels);
912 }
913
914 static void show_numstat(struct diffstat_t* data, struct diff_options *options)
915 {
916         int i;
917
918         if (data->nr == 0)
919                 return;
920
921         for (i = 0; i < data->nr; i++) {
922                 struct diffstat_file *file = data->files[i];
923
924                 if (file->is_binary)
925                         fprintf(options->file, "-\t-\t");
926                 else
927                         fprintf(options->file,
928                                 "%d\t%d\t", file->added, file->deleted);
929                 if (options->line_termination) {
930                         fill_print_name(file);
931                         if (!file->is_renamed)
932                                 write_name_quoted(file->name, options->file,
933                                                   options->line_termination);
934                         else {
935                                 fputs(file->print_name, options->file);
936                                 putc(options->line_termination, options->file);
937                         }
938                 } else {
939                         if (file->is_renamed) {
940                                 putc('\0', options->file);
941                                 write_name_quoted(file->from_name, options->file, '\0');
942                         }
943                         write_name_quoted(file->name, options->file, '\0');
944                 }
945         }
946 }
947
948 struct dirstat_file {
949         const char *name;
950         unsigned long changed;
951 };
952
953 struct dirstat_dir {
954         struct dirstat_file *files;
955         int alloc, nr, percent, cumulative;
956 };
957
958 static long gather_dirstat(FILE *file, struct dirstat_dir *dir, unsigned long changed, const char *base, int baselen)
959 {
960         unsigned long this_dir = 0;
961         unsigned int sources = 0;
962
963         while (dir->nr) {
964                 struct dirstat_file *f = dir->files;
965                 int namelen = strlen(f->name);
966                 unsigned long this;
967                 char *slash;
968
969                 if (namelen < baselen)
970                         break;
971                 if (memcmp(f->name, base, baselen))
972                         break;
973                 slash = strchr(f->name + baselen, '/');
974                 if (slash) {
975                         int newbaselen = slash + 1 - f->name;
976                         this = gather_dirstat(file, dir, changed, f->name, newbaselen);
977                         sources++;
978                 } else {
979                         this = f->changed;
980                         dir->files++;
981                         dir->nr--;
982                         sources += 2;
983                 }
984                 this_dir += this;
985         }
986
987         /*
988          * We don't report dirstat's for
989          *  - the top level
990          *  - or cases where everything came from a single directory
991          *    under this directory (sources == 1).
992          */
993         if (baselen && sources != 1) {
994                 int permille = this_dir * 1000 / changed;
995                 if (permille) {
996                         int percent = permille / 10;
997                         if (percent >= dir->percent) {
998                                 fprintf(file, "%4d.%01d%% %.*s\n", percent, permille % 10, baselen, base);
999                                 if (!dir->cumulative)
1000                                         return 0;
1001                         }
1002                 }
1003         }
1004         return this_dir;
1005 }
1006
1007 static int dirstat_compare(const void *_a, const void *_b)
1008 {
1009         const struct dirstat_file *a = _a;
1010         const struct dirstat_file *b = _b;
1011         return strcmp(a->name, b->name);
1012 }
1013
1014 static void show_dirstat(struct diff_options *options)
1015 {
1016         int i;
1017         unsigned long changed;
1018         struct dirstat_dir dir;
1019         struct diff_queue_struct *q = &diff_queued_diff;
1020
1021         dir.files = NULL;
1022         dir.alloc = 0;
1023         dir.nr = 0;
1024         dir.percent = options->dirstat_percent;
1025         dir.cumulative = DIFF_OPT_TST(options, DIRSTAT_CUMULATIVE);
1026
1027         changed = 0;
1028         for (i = 0; i < q->nr; i++) {
1029                 struct diff_filepair *p = q->queue[i];
1030                 const char *name;
1031                 unsigned long copied, added, damage;
1032
1033                 name = p->one->path ? p->one->path : p->two->path;
1034
1035                 if (DIFF_FILE_VALID(p->one) && DIFF_FILE_VALID(p->two)) {
1036                         diff_populate_filespec(p->one, 0);
1037                         diff_populate_filespec(p->two, 0);
1038                         diffcore_count_changes(p->one, p->two, NULL, NULL, 0,
1039                                                &copied, &added);
1040                         diff_free_filespec_data(p->one);
1041                         diff_free_filespec_data(p->two);
1042                 } else if (DIFF_FILE_VALID(p->one)) {
1043                         diff_populate_filespec(p->one, 1);
1044                         copied = added = 0;
1045                         diff_free_filespec_data(p->one);
1046                 } else if (DIFF_FILE_VALID(p->two)) {
1047                         diff_populate_filespec(p->two, 1);
1048                         copied = 0;
1049                         added = p->two->size;
1050                         diff_free_filespec_data(p->two);
1051                 } else
1052                         continue;
1053
1054                 /*
1055                  * Original minus copied is the removed material,
1056                  * added is the new material.  They are both damages
1057                  * made to the preimage. In --dirstat-by-file mode, count
1058                  * damaged files, not damaged lines. This is done by
1059                  * counting only a single damaged line per file.
1060                  */
1061                 damage = (p->one->size - copied) + added;
1062                 if (DIFF_OPT_TST(options, DIRSTAT_BY_FILE) && damage > 0)
1063                         damage = 1;
1064
1065                 ALLOC_GROW(dir.files, dir.nr + 1, dir.alloc);
1066                 dir.files[dir.nr].name = name;
1067                 dir.files[dir.nr].changed = damage;
1068                 changed += damage;
1069                 dir.nr++;
1070         }
1071
1072         /* This can happen even with many files, if everything was renames */
1073         if (!changed)
1074                 return;
1075
1076         /* Show all directories with more than x% of the changes */
1077         qsort(dir.files, dir.nr, sizeof(dir.files[0]), dirstat_compare);
1078         gather_dirstat(options->file, &dir, changed, "", 0);
1079 }
1080
1081 static void free_diffstat_info(struct diffstat_t *diffstat)
1082 {
1083         int i;
1084         for (i = 0; i < diffstat->nr; i++) {
1085                 struct diffstat_file *f = diffstat->files[i];
1086                 if (f->name != f->print_name)
1087                         free(f->print_name);
1088                 free(f->name);
1089                 free(f->from_name);
1090                 free(f);
1091         }
1092         free(diffstat->files);
1093 }
1094
1095 struct checkdiff_t {
1096         const char *filename;
1097         int lineno;
1098         struct diff_options *o;
1099         unsigned ws_rule;
1100         unsigned status;
1101         int trailing_blanks_start;
1102 };
1103
1104 static int is_conflict_marker(const char *line, unsigned long len)
1105 {
1106         char firstchar;
1107         int cnt;
1108
1109         if (len < 8)
1110                 return 0;
1111         firstchar = line[0];
1112         switch (firstchar) {
1113         case '=': case '>': case '<':
1114                 break;
1115         default:
1116                 return 0;
1117         }
1118         for (cnt = 1; cnt < 7; cnt++)
1119                 if (line[cnt] != firstchar)
1120                         return 0;
1121         /* line[0] thru line[6] are same as firstchar */
1122         if (firstchar == '=') {
1123                 /* divider between ours and theirs? */
1124                 if (len != 8 || line[7] != '\n')
1125                         return 0;
1126         } else if (len < 8 || !isspace(line[7])) {
1127                 /* not divider before ours nor after theirs */
1128                 return 0;
1129         }
1130         return 1;
1131 }
1132
1133 static void checkdiff_consume(void *priv, char *line, unsigned long len)
1134 {
1135         struct checkdiff_t *data = priv;
1136         int color_diff = DIFF_OPT_TST(data->o, COLOR_DIFF);
1137         const char *ws = diff_get_color(color_diff, DIFF_WHITESPACE);
1138         const char *reset = diff_get_color(color_diff, DIFF_RESET);
1139         const char *set = diff_get_color(color_diff, DIFF_FILE_NEW);
1140         char *err;
1141
1142         if (line[0] == '+') {
1143                 unsigned bad;
1144                 data->lineno++;
1145                 if (!ws_blank_line(line + 1, len - 1, data->ws_rule))
1146                         data->trailing_blanks_start = 0;
1147                 else if (!data->trailing_blanks_start)
1148                         data->trailing_blanks_start = data->lineno;
1149                 if (is_conflict_marker(line + 1, len - 1)) {
1150                         data->status |= 1;
1151                         fprintf(data->o->file,
1152                                 "%s:%d: leftover conflict marker\n",
1153                                 data->filename, data->lineno);
1154                 }
1155                 bad = ws_check(line + 1, len - 1, data->ws_rule);
1156                 if (!bad)
1157                         return;
1158                 data->status |= bad;
1159                 err = whitespace_error_string(bad);
1160                 fprintf(data->o->file, "%s:%d: %s.\n",
1161                         data->filename, data->lineno, err);
1162                 free(err);
1163                 emit_line(data->o->file, set, reset, line, 1);
1164                 ws_check_emit(line + 1, len - 1, data->ws_rule,
1165                               data->o->file, set, reset, ws);
1166         } else if (line[0] == ' ') {
1167                 data->lineno++;
1168                 data->trailing_blanks_start = 0;
1169         } else if (line[0] == '@') {
1170                 char *plus = strchr(line, '+');
1171                 if (plus)
1172                         data->lineno = strtol(plus, NULL, 10) - 1;
1173                 else
1174                         die("invalid diff");
1175                 data->trailing_blanks_start = 0;
1176         }
1177 }
1178
1179 static unsigned char *deflate_it(char *data,
1180                                  unsigned long size,
1181                                  unsigned long *result_size)
1182 {
1183         int bound;
1184         unsigned char *deflated;
1185         z_stream stream;
1186
1187         memset(&stream, 0, sizeof(stream));
1188         deflateInit(&stream, zlib_compression_level);
1189         bound = deflateBound(&stream, size);
1190         deflated = xmalloc(bound);
1191         stream.next_out = deflated;
1192         stream.avail_out = bound;
1193
1194         stream.next_in = (unsigned char *)data;
1195         stream.avail_in = size;
1196         while (deflate(&stream, Z_FINISH) == Z_OK)
1197                 ; /* nothing */
1198         deflateEnd(&stream);
1199         *result_size = stream.total_out;
1200         return deflated;
1201 }
1202
1203 static void emit_binary_diff_body(FILE *file, mmfile_t *one, mmfile_t *two)
1204 {
1205         void *cp;
1206         void *delta;
1207         void *deflated;
1208         void *data;
1209         unsigned long orig_size;
1210         unsigned long delta_size;
1211         unsigned long deflate_size;
1212         unsigned long data_size;
1213
1214         /* We could do deflated delta, or we could do just deflated two,
1215          * whichever is smaller.
1216          */
1217         delta = NULL;
1218         deflated = deflate_it(two->ptr, two->size, &deflate_size);
1219         if (one->size && two->size) {
1220                 delta = diff_delta(one->ptr, one->size,
1221                                    two->ptr, two->size,
1222                                    &delta_size, deflate_size);
1223                 if (delta) {
1224                         void *to_free = delta;
1225                         orig_size = delta_size;
1226                         delta = deflate_it(delta, delta_size, &delta_size);
1227                         free(to_free);
1228                 }
1229         }
1230
1231         if (delta && delta_size < deflate_size) {
1232                 fprintf(file, "delta %lu\n", orig_size);
1233                 free(deflated);
1234                 data = delta;
1235                 data_size = delta_size;
1236         }
1237         else {
1238                 fprintf(file, "literal %lu\n", two->size);
1239                 free(delta);
1240                 data = deflated;
1241                 data_size = deflate_size;
1242         }
1243
1244         /* emit data encoded in base85 */
1245         cp = data;
1246         while (data_size) {
1247                 int bytes = (52 < data_size) ? 52 : data_size;
1248                 char line[70];
1249                 data_size -= bytes;
1250                 if (bytes <= 26)
1251                         line[0] = bytes + 'A' - 1;
1252                 else
1253                         line[0] = bytes - 26 + 'a' - 1;
1254                 encode_85(line + 1, cp, bytes);
1255                 cp = (char *) cp + bytes;
1256                 fputs(line, file);
1257                 fputc('\n', file);
1258         }
1259         fprintf(file, "\n");
1260         free(data);
1261 }
1262
1263 static void emit_binary_diff(FILE *file, mmfile_t *one, mmfile_t *two)
1264 {
1265         fprintf(file, "GIT binary patch\n");
1266         emit_binary_diff_body(file, one, two);
1267         emit_binary_diff_body(file, two, one);
1268 }
1269
1270 static void diff_filespec_load_driver(struct diff_filespec *one)
1271 {
1272         if (!one->driver)
1273                 one->driver = userdiff_find_by_path(one->path);
1274         if (!one->driver)
1275                 one->driver = userdiff_find_by_name("default");
1276 }
1277
1278 int diff_filespec_is_binary(struct diff_filespec *one)
1279 {
1280         if (one->is_binary == -1) {
1281                 diff_filespec_load_driver(one);
1282                 if (one->driver->binary != -1)
1283                         one->is_binary = one->driver->binary;
1284                 else {
1285                         if (!one->data && DIFF_FILE_VALID(one))
1286                                 diff_populate_filespec(one, 0);
1287                         if (one->data)
1288                                 one->is_binary = buffer_is_binary(one->data,
1289                                                 one->size);
1290                         if (one->is_binary == -1)
1291                                 one->is_binary = 0;
1292                 }
1293         }
1294         return one->is_binary;
1295 }
1296
1297 static const struct userdiff_funcname *diff_funcname_pattern(struct diff_filespec *one)
1298 {
1299         diff_filespec_load_driver(one);
1300         return one->driver->funcname.pattern ? &one->driver->funcname : NULL;
1301 }
1302
1303 void diff_set_mnemonic_prefix(struct diff_options *options, const char *a, const char *b)
1304 {
1305         if (!options->a_prefix)
1306                 options->a_prefix = a;
1307         if (!options->b_prefix)
1308                 options->b_prefix = b;
1309 }
1310
1311 static const char *get_textconv(struct diff_filespec *one)
1312 {
1313         if (!DIFF_FILE_VALID(one))
1314                 return NULL;
1315         if (!S_ISREG(one->mode))
1316                 return NULL;
1317         diff_filespec_load_driver(one);
1318         return one->driver->textconv;
1319 }
1320
1321 static void builtin_diff(const char *name_a,
1322                          const char *name_b,
1323                          struct diff_filespec *one,
1324                          struct diff_filespec *two,
1325                          const char *xfrm_msg,
1326                          struct diff_options *o,
1327                          int complete_rewrite)
1328 {
1329         mmfile_t mf1, mf2;
1330         const char *lbl[2];
1331         char *a_one, *b_two;
1332         const char *set = diff_get_color_opt(o, DIFF_METAINFO);
1333         const char *reset = diff_get_color_opt(o, DIFF_RESET);
1334         const char *a_prefix, *b_prefix;
1335         const char *textconv_one = NULL, *textconv_two = NULL;
1336
1337         diff_set_mnemonic_prefix(o, "a/", "b/");
1338         if (DIFF_OPT_TST(o, REVERSE_DIFF)) {
1339                 a_prefix = o->b_prefix;
1340                 b_prefix = o->a_prefix;
1341         } else {
1342                 a_prefix = o->a_prefix;
1343                 b_prefix = o->b_prefix;
1344         }
1345
1346         /* Never use a non-valid filename anywhere if at all possible */
1347         name_a = DIFF_FILE_VALID(one) ? name_a : name_b;
1348         name_b = DIFF_FILE_VALID(two) ? name_b : name_a;
1349
1350         a_one = quote_two(a_prefix, name_a + (*name_a == '/'));
1351         b_two = quote_two(b_prefix, name_b + (*name_b == '/'));
1352         lbl[0] = DIFF_FILE_VALID(one) ? a_one : "/dev/null";
1353         lbl[1] = DIFF_FILE_VALID(two) ? b_two : "/dev/null";
1354         fprintf(o->file, "%sdiff --git %s %s%s\n", set, a_one, b_two, reset);
1355         if (lbl[0][0] == '/') {
1356                 /* /dev/null */
1357                 fprintf(o->file, "%snew file mode %06o%s\n", set, two->mode, reset);
1358                 if (xfrm_msg && xfrm_msg[0])
1359                         fprintf(o->file, "%s%s%s\n", set, xfrm_msg, reset);
1360         }
1361         else if (lbl[1][0] == '/') {
1362                 fprintf(o->file, "%sdeleted file mode %06o%s\n", set, one->mode, reset);
1363                 if (xfrm_msg && xfrm_msg[0])
1364                         fprintf(o->file, "%s%s%s\n", set, xfrm_msg, reset);
1365         }
1366         else {
1367                 if (one->mode != two->mode) {
1368                         fprintf(o->file, "%sold mode %06o%s\n", set, one->mode, reset);
1369                         fprintf(o->file, "%snew mode %06o%s\n", set, two->mode, reset);
1370                 }
1371                 if (xfrm_msg && xfrm_msg[0])
1372                         fprintf(o->file, "%s%s%s\n", set, xfrm_msg, reset);
1373                 /*
1374                  * we do not run diff between different kind
1375                  * of objects.
1376                  */
1377                 if ((one->mode ^ two->mode) & S_IFMT)
1378                         goto free_ab_and_return;
1379                 if (complete_rewrite) {
1380                         emit_rewrite_diff(name_a, name_b, one, two, o);
1381                         o->found_changes = 1;
1382                         goto free_ab_and_return;
1383                 }
1384         }
1385
1386         if (fill_mmfile(&mf1, one) < 0 || fill_mmfile(&mf2, two) < 0)
1387                 die("unable to read files to diff");
1388
1389         if (DIFF_OPT_TST(o, ALLOW_TEXTCONV)) {
1390                 textconv_one = get_textconv(one);
1391                 textconv_two = get_textconv(two);
1392         }
1393
1394         if (!DIFF_OPT_TST(o, TEXT) &&
1395             ( (diff_filespec_is_binary(one) && !textconv_one) ||
1396               (diff_filespec_is_binary(two) && !textconv_two) )) {
1397                 /* Quite common confusing case */
1398                 if (mf1.size == mf2.size &&
1399                     !memcmp(mf1.ptr, mf2.ptr, mf1.size))
1400                         goto free_ab_and_return;
1401                 if (DIFF_OPT_TST(o, BINARY))
1402                         emit_binary_diff(o->file, &mf1, &mf2);
1403                 else
1404                         fprintf(o->file, "Binary files %s and %s differ\n",
1405                                 lbl[0], lbl[1]);
1406                 o->found_changes = 1;
1407         }
1408         else {
1409                 /* Crazy xdl interfaces.. */
1410                 const char *diffopts = getenv("GIT_DIFF_OPTS");
1411                 xpparam_t xpp;
1412                 xdemitconf_t xecfg;
1413                 xdemitcb_t ecb;
1414                 struct emit_callback ecbdata;
1415                 const struct userdiff_funcname *pe;
1416
1417                 if (textconv_one) {
1418                         size_t size;
1419                         mf1.ptr = run_textconv(textconv_one, one, &size);
1420                         if (!mf1.ptr)
1421                                 die("unable to read files to diff");
1422                         mf1.size = size;
1423                 }
1424                 if (textconv_two) {
1425                         size_t size;
1426                         mf2.ptr = run_textconv(textconv_two, two, &size);
1427                         if (!mf2.ptr)
1428                                 die("unable to read files to diff");
1429                         mf2.size = size;
1430                 }
1431
1432                 pe = diff_funcname_pattern(one);
1433                 if (!pe)
1434                         pe = diff_funcname_pattern(two);
1435
1436                 memset(&xpp, 0, sizeof(xpp));
1437                 memset(&xecfg, 0, sizeof(xecfg));
1438                 memset(&ecbdata, 0, sizeof(ecbdata));
1439                 ecbdata.label_path = lbl;
1440                 ecbdata.color_diff = DIFF_OPT_TST(o, COLOR_DIFF);
1441                 ecbdata.found_changesp = &o->found_changes;
1442                 ecbdata.ws_rule = whitespace_rule(name_b ? name_b : name_a);
1443                 ecbdata.file = o->file;
1444                 xpp.flags = XDF_NEED_MINIMAL | o->xdl_opts;
1445                 xecfg.ctxlen = o->context;
1446                 xecfg.flags = XDL_EMIT_FUNCNAMES;
1447                 if (pe)
1448                         xdiff_set_find_func(&xecfg, pe->pattern, pe->cflags);
1449                 if (!diffopts)
1450                         ;
1451                 else if (!prefixcmp(diffopts, "--unified="))
1452                         xecfg.ctxlen = strtoul(diffopts + 10, NULL, 10);
1453                 else if (!prefixcmp(diffopts, "-u"))
1454                         xecfg.ctxlen = strtoul(diffopts + 2, NULL, 10);
1455                 if (DIFF_OPT_TST(o, COLOR_DIFF_WORDS)) {
1456                         ecbdata.diff_words =
1457                                 xcalloc(1, sizeof(struct diff_words_data));
1458                         ecbdata.diff_words->file = o->file;
1459                 }
1460                 xdi_diff_outf(&mf1, &mf2, fn_out_consume, &ecbdata,
1461                               &xpp, &xecfg, &ecb);
1462                 if (DIFF_OPT_TST(o, COLOR_DIFF_WORDS))
1463                         free_diff_words_data(&ecbdata);
1464                 if (textconv_one)
1465                         free(mf1.ptr);
1466                 if (textconv_two)
1467                         free(mf2.ptr);
1468         }
1469
1470  free_ab_and_return:
1471         diff_free_filespec_data(one);
1472         diff_free_filespec_data(two);
1473         free(a_one);
1474         free(b_two);
1475         return;
1476 }
1477
1478 static void builtin_diffstat(const char *name_a, const char *name_b,
1479                              struct diff_filespec *one,
1480                              struct diff_filespec *two,
1481                              struct diffstat_t *diffstat,
1482                              struct diff_options *o,
1483                              int complete_rewrite)
1484 {
1485         mmfile_t mf1, mf2;
1486         struct diffstat_file *data;
1487
1488         data = diffstat_add(diffstat, name_a, name_b);
1489
1490         if (!one || !two) {
1491                 data->is_unmerged = 1;
1492                 return;
1493         }
1494         if (complete_rewrite) {
1495                 diff_populate_filespec(one, 0);
1496                 diff_populate_filespec(two, 0);
1497                 data->deleted = count_lines(one->data, one->size);
1498                 data->added = count_lines(two->data, two->size);
1499                 goto free_and_return;
1500         }
1501         if (fill_mmfile(&mf1, one) < 0 || fill_mmfile(&mf2, two) < 0)
1502                 die("unable to read files to diff");
1503
1504         if (diff_filespec_is_binary(one) || diff_filespec_is_binary(two)) {
1505                 data->is_binary = 1;
1506                 data->added = mf2.size;
1507                 data->deleted = mf1.size;
1508         } else {
1509                 /* Crazy xdl interfaces.. */
1510                 xpparam_t xpp;
1511                 xdemitconf_t xecfg;
1512                 xdemitcb_t ecb;
1513
1514                 memset(&xpp, 0, sizeof(xpp));
1515                 memset(&xecfg, 0, sizeof(xecfg));
1516                 xpp.flags = XDF_NEED_MINIMAL | o->xdl_opts;
1517                 xdi_diff_outf(&mf1, &mf2, diffstat_consume, diffstat,
1518                               &xpp, &xecfg, &ecb);
1519         }
1520
1521  free_and_return:
1522         diff_free_filespec_data(one);
1523         diff_free_filespec_data(two);
1524 }
1525
1526 static void builtin_checkdiff(const char *name_a, const char *name_b,
1527                               const char *attr_path,
1528                               struct diff_filespec *one,
1529                               struct diff_filespec *two,
1530                               struct diff_options *o)
1531 {
1532         mmfile_t mf1, mf2;
1533         struct checkdiff_t data;
1534
1535         if (!two)
1536                 return;
1537
1538         memset(&data, 0, sizeof(data));
1539         data.filename = name_b ? name_b : name_a;
1540         data.lineno = 0;
1541         data.o = o;
1542         data.ws_rule = whitespace_rule(attr_path);
1543
1544         if (fill_mmfile(&mf1, one) < 0 || fill_mmfile(&mf2, two) < 0)
1545                 die("unable to read files to diff");
1546
1547         /*
1548          * All the other codepaths check both sides, but not checking
1549          * the "old" side here is deliberate.  We are checking the newly
1550          * introduced changes, and as long as the "new" side is text, we
1551          * can and should check what it introduces.
1552          */
1553         if (diff_filespec_is_binary(two))
1554                 goto free_and_return;
1555         else {
1556                 /* Crazy xdl interfaces.. */
1557                 xpparam_t xpp;
1558                 xdemitconf_t xecfg;
1559                 xdemitcb_t ecb;
1560
1561                 memset(&xpp, 0, sizeof(xpp));
1562                 memset(&xecfg, 0, sizeof(xecfg));
1563                 xecfg.ctxlen = 1; /* at least one context line */
1564                 xpp.flags = XDF_NEED_MINIMAL;
1565                 xdi_diff_outf(&mf1, &mf2, checkdiff_consume, &data,
1566                               &xpp, &xecfg, &ecb);
1567
1568                 if ((data.ws_rule & WS_TRAILING_SPACE) &&
1569                     data.trailing_blanks_start) {
1570                         fprintf(o->file, "%s:%d: ends with blank lines.\n",
1571                                 data.filename, data.trailing_blanks_start);
1572                         data.status = 1; /* report errors */
1573                 }
1574         }
1575  free_and_return:
1576         diff_free_filespec_data(one);
1577         diff_free_filespec_data(two);
1578         if (data.status)
1579                 DIFF_OPT_SET(o, CHECK_FAILED);
1580 }
1581
1582 struct diff_filespec *alloc_filespec(const char *path)
1583 {
1584         int namelen = strlen(path);
1585         struct diff_filespec *spec = xmalloc(sizeof(*spec) + namelen + 1);
1586
1587         memset(spec, 0, sizeof(*spec));
1588         spec->path = (char *)(spec + 1);
1589         memcpy(spec->path, path, namelen+1);
1590         spec->count = 1;
1591         spec->is_binary = -1;
1592         return spec;
1593 }
1594
1595 void free_filespec(struct diff_filespec *spec)
1596 {
1597         if (!--spec->count) {
1598                 diff_free_filespec_data(spec);
1599                 free(spec);
1600         }
1601 }
1602
1603 void fill_filespec(struct diff_filespec *spec, const unsigned char *sha1,
1604                    unsigned short mode)
1605 {
1606         if (mode) {
1607                 spec->mode = canon_mode(mode);
1608                 hashcpy(spec->sha1, sha1);
1609                 spec->sha1_valid = !is_null_sha1(sha1);
1610         }
1611 }
1612
1613 /*
1614  * Given a name and sha1 pair, if the index tells us the file in
1615  * the work tree has that object contents, return true, so that
1616  * prepare_temp_file() does not have to inflate and extract.
1617  */
1618 static int reuse_worktree_file(const char *name, const unsigned char *sha1, int want_file)
1619 {
1620         struct cache_entry *ce;
1621         struct stat st;
1622         int pos, len;
1623
1624         /* We do not read the cache ourselves here, because the
1625          * benchmark with my previous version that always reads cache
1626          * shows that it makes things worse for diff-tree comparing
1627          * two linux-2.6 kernel trees in an already checked out work
1628          * tree.  This is because most diff-tree comparisons deal with
1629          * only a small number of files, while reading the cache is
1630          * expensive for a large project, and its cost outweighs the
1631          * savings we get by not inflating the object to a temporary
1632          * file.  Practically, this code only helps when we are used
1633          * by diff-cache --cached, which does read the cache before
1634          * calling us.
1635          */
1636         if (!active_cache)
1637                 return 0;
1638
1639         /* We want to avoid the working directory if our caller
1640          * doesn't need the data in a normal file, this system
1641          * is rather slow with its stat/open/mmap/close syscalls,
1642          * and the object is contained in a pack file.  The pack
1643          * is probably already open and will be faster to obtain
1644          * the data through than the working directory.  Loose
1645          * objects however would tend to be slower as they need
1646          * to be individually opened and inflated.
1647          */
1648         if (!FAST_WORKING_DIRECTORY && !want_file && has_sha1_pack(sha1, NULL))
1649                 return 0;
1650
1651         len = strlen(name);
1652         pos = cache_name_pos(name, len);
1653         if (pos < 0)
1654                 return 0;
1655         ce = active_cache[pos];
1656
1657         /*
1658          * This is not the sha1 we are looking for, or
1659          * unreusable because it is not a regular file.
1660          */
1661         if (hashcmp(sha1, ce->sha1) || !S_ISREG(ce->ce_mode))
1662                 return 0;
1663
1664         /*
1665          * If ce matches the file in the work tree, we can reuse it.
1666          */
1667         if (ce_uptodate(ce) ||
1668             (!lstat(name, &st) && !ce_match_stat(ce, &st, 0)))
1669                 return 1;
1670
1671         return 0;
1672 }
1673
1674 static int populate_from_stdin(struct diff_filespec *s)
1675 {
1676         struct strbuf buf = STRBUF_INIT;
1677         size_t size = 0;
1678
1679         if (strbuf_read(&buf, 0, 0) < 0)
1680                 return error("error while reading from stdin %s",
1681                                      strerror(errno));
1682
1683         s->should_munmap = 0;
1684         s->data = strbuf_detach(&buf, &size);
1685         s->size = size;
1686         s->should_free = 1;
1687         return 0;
1688 }
1689
1690 static int diff_populate_gitlink(struct diff_filespec *s, int size_only)
1691 {
1692         int len;
1693         char *data = xmalloc(100);
1694         len = snprintf(data, 100,
1695                 "Subproject commit %s\n", sha1_to_hex(s->sha1));
1696         s->data = data;
1697         s->size = len;
1698         s->should_free = 1;
1699         if (size_only) {
1700                 s->data = NULL;
1701                 free(data);
1702         }
1703         return 0;
1704 }
1705
1706 /*
1707  * While doing rename detection and pickaxe operation, we may need to
1708  * grab the data for the blob (or file) for our own in-core comparison.
1709  * diff_filespec has data and size fields for this purpose.
1710  */
1711 int diff_populate_filespec(struct diff_filespec *s, int size_only)
1712 {
1713         int err = 0;
1714         if (!DIFF_FILE_VALID(s))
1715                 die("internal error: asking to populate invalid file.");
1716         if (S_ISDIR(s->mode))
1717                 return -1;
1718
1719         if (s->data)
1720                 return 0;
1721
1722         if (size_only && 0 < s->size)
1723                 return 0;
1724
1725         if (S_ISGITLINK(s->mode))
1726                 return diff_populate_gitlink(s, size_only);
1727
1728         if (!s->sha1_valid ||
1729             reuse_worktree_file(s->path, s->sha1, 0)) {
1730                 struct strbuf buf = STRBUF_INIT;
1731                 struct stat st;
1732                 int fd;
1733
1734                 if (!strcmp(s->path, "-"))
1735                         return populate_from_stdin(s);
1736
1737                 if (lstat(s->path, &st) < 0) {
1738                         if (errno == ENOENT) {
1739                         err_empty:
1740                                 err = -1;
1741                         empty:
1742                                 s->data = (char *)"";
1743                                 s->size = 0;
1744                                 return err;
1745                         }
1746                 }
1747                 s->size = xsize_t(st.st_size);
1748                 if (!s->size)
1749                         goto empty;
1750                 if (size_only)
1751                         return 0;
1752                 if (S_ISLNK(st.st_mode)) {
1753                         int ret;
1754                         s->data = xmalloc(s->size);
1755                         s->should_free = 1;
1756                         ret = readlink(s->path, s->data, s->size);
1757                         if (ret < 0) {
1758                                 free(s->data);
1759                                 goto err_empty;
1760                         }
1761                         return 0;
1762                 }
1763                 fd = open(s->path, O_RDONLY);
1764                 if (fd < 0)
1765                         goto err_empty;
1766                 s->data = xmmap(NULL, s->size, PROT_READ, MAP_PRIVATE, fd, 0);
1767                 close(fd);
1768                 s->should_munmap = 1;
1769
1770                 /*
1771                  * Convert from working tree format to canonical git format
1772                  */
1773                 if (convert_to_git(s->path, s->data, s->size, &buf, safe_crlf)) {
1774                         size_t size = 0;
1775                         munmap(s->data, s->size);
1776                         s->should_munmap = 0;
1777                         s->data = strbuf_detach(&buf, &size);
1778                         s->size = size;
1779                         s->should_free = 1;
1780                 }
1781         }
1782         else {
1783                 enum object_type type;
1784                 if (size_only)
1785                         type = sha1_object_info(s->sha1, &s->size);
1786                 else {
1787                         s->data = read_sha1_file(s->sha1, &type, &s->size);
1788                         s->should_free = 1;
1789                 }
1790         }
1791         return 0;
1792 }
1793
1794 void diff_free_filespec_blob(struct diff_filespec *s)
1795 {
1796         if (s->should_free)
1797                 free(s->data);
1798         else if (s->should_munmap)
1799                 munmap(s->data, s->size);
1800
1801         if (s->should_free || s->should_munmap) {
1802                 s->should_free = s->should_munmap = 0;
1803                 s->data = NULL;
1804         }
1805 }
1806
1807 void diff_free_filespec_data(struct diff_filespec *s)
1808 {
1809         diff_free_filespec_blob(s);
1810         free(s->cnt_data);
1811         s->cnt_data = NULL;
1812 }
1813
1814 static void prep_temp_blob(struct diff_tempfile *temp,
1815                            void *blob,
1816                            unsigned long size,
1817                            const unsigned char *sha1,
1818                            int mode)
1819 {
1820         int fd;
1821
1822         fd = git_mkstemp(temp->tmp_path, PATH_MAX, ".diff_XXXXXX");
1823         if (fd < 0)
1824                 die("unable to create temp-file: %s", strerror(errno));
1825         if (write_in_full(fd, blob, size) != size)
1826                 die("unable to write temp-file");
1827         close(fd);
1828         temp->name = temp->tmp_path;
1829         strcpy(temp->hex, sha1_to_hex(sha1));
1830         temp->hex[40] = 0;
1831         sprintf(temp->mode, "%06o", mode);
1832 }
1833
1834 static void prepare_temp_file(const char *name,
1835                               struct diff_tempfile *temp,
1836                               struct diff_filespec *one)
1837 {
1838         if (!DIFF_FILE_VALID(one)) {
1839         not_a_valid_file:
1840                 /* A '-' entry produces this for file-2, and
1841                  * a '+' entry produces this for file-1.
1842                  */
1843                 temp->name = "/dev/null";
1844                 strcpy(temp->hex, ".");
1845                 strcpy(temp->mode, ".");
1846                 return;
1847         }
1848
1849         if (!one->sha1_valid ||
1850             reuse_worktree_file(name, one->sha1, 1)) {
1851                 struct stat st;
1852                 if (lstat(name, &st) < 0) {
1853                         if (errno == ENOENT)
1854                                 goto not_a_valid_file;
1855                         die("stat(%s): %s", name, strerror(errno));
1856                 }
1857                 if (S_ISLNK(st.st_mode)) {
1858                         int ret;
1859                         char buf[PATH_MAX + 1]; /* ought to be SYMLINK_MAX */
1860                         size_t sz = xsize_t(st.st_size);
1861                         if (sizeof(buf) <= st.st_size)
1862                                 die("symlink too long: %s", name);
1863                         ret = readlink(name, buf, sz);
1864                         if (ret < 0)
1865                                 die("readlink(%s)", name);
1866                         prep_temp_blob(temp, buf, sz,
1867                                        (one->sha1_valid ?
1868                                         one->sha1 : null_sha1),
1869                                        (one->sha1_valid ?
1870                                         one->mode : S_IFLNK));
1871                 }
1872                 else {
1873                         /* we can borrow from the file in the work tree */
1874                         temp->name = name;
1875                         if (!one->sha1_valid)
1876                                 strcpy(temp->hex, sha1_to_hex(null_sha1));
1877                         else
1878                                 strcpy(temp->hex, sha1_to_hex(one->sha1));
1879                         /* Even though we may sometimes borrow the
1880                          * contents from the work tree, we always want
1881                          * one->mode.  mode is trustworthy even when
1882                          * !(one->sha1_valid), as long as
1883                          * DIFF_FILE_VALID(one).
1884                          */
1885                         sprintf(temp->mode, "%06o", one->mode);
1886                 }
1887                 return;
1888         }
1889         else {
1890                 if (diff_populate_filespec(one, 0))
1891                         die("cannot read data blob for %s", one->path);
1892                 prep_temp_blob(temp, one->data, one->size,
1893                                one->sha1, one->mode);
1894         }
1895 }
1896
1897 static void remove_tempfile(void)
1898 {
1899         int i;
1900
1901         for (i = 0; i < 2; i++)
1902                 if (diff_temp[i].name == diff_temp[i].tmp_path) {
1903                         unlink(diff_temp[i].name);
1904                         diff_temp[i].name = NULL;
1905                 }
1906 }
1907
1908 static void remove_tempfile_on_signal(int signo)
1909 {
1910         remove_tempfile();
1911         signal(SIGINT, SIG_DFL);
1912         raise(signo);
1913 }
1914
1915 /* An external diff command takes:
1916  *
1917  * diff-cmd name infile1 infile1-sha1 infile1-mode \
1918  *               infile2 infile2-sha1 infile2-mode [ rename-to ]
1919  *
1920  */
1921 static void run_external_diff(const char *pgm,
1922                               const char *name,
1923                               const char *other,
1924                               struct diff_filespec *one,
1925                               struct diff_filespec *two,
1926                               const char *xfrm_msg,
1927                               int complete_rewrite)
1928 {
1929         const char *spawn_arg[10];
1930         struct diff_tempfile *temp = diff_temp;
1931         int retval;
1932         static int atexit_asked = 0;
1933         const char *othername;
1934         const char **arg = &spawn_arg[0];
1935
1936         othername = (other? other : name);
1937         if (one && two) {
1938                 prepare_temp_file(name, &temp[0], one);
1939                 prepare_temp_file(othername, &temp[1], two);
1940                 if (! atexit_asked &&
1941                     (temp[0].name == temp[0].tmp_path ||
1942                      temp[1].name == temp[1].tmp_path)) {
1943                         atexit_asked = 1;
1944                         atexit(remove_tempfile);
1945                 }
1946                 signal(SIGINT, remove_tempfile_on_signal);
1947         }
1948
1949         if (one && two) {
1950                 *arg++ = pgm;
1951                 *arg++ = name;
1952                 *arg++ = temp[0].name;
1953                 *arg++ = temp[0].hex;
1954                 *arg++ = temp[0].mode;
1955                 *arg++ = temp[1].name;
1956                 *arg++ = temp[1].hex;
1957                 *arg++ = temp[1].mode;
1958                 if (other) {
1959                         *arg++ = other;
1960                         *arg++ = xfrm_msg;
1961                 }
1962         } else {
1963                 *arg++ = pgm;
1964                 *arg++ = name;
1965         }
1966         *arg = NULL;
1967         fflush(NULL);
1968         retval = run_command_v_opt(spawn_arg, 0);
1969         remove_tempfile();
1970         if (retval) {
1971                 fprintf(stderr, "external diff died, stopping at %s.\n", name);
1972                 exit(1);
1973         }
1974 }
1975
1976 static void run_diff_cmd(const char *pgm,
1977                          const char *name,
1978                          const char *other,
1979                          const char *attr_path,
1980                          struct diff_filespec *one,
1981                          struct diff_filespec *two,
1982                          const char *xfrm_msg,
1983                          struct diff_options *o,
1984                          int complete_rewrite)
1985 {
1986         if (!DIFF_OPT_TST(o, ALLOW_EXTERNAL))
1987                 pgm = NULL;
1988         else {
1989                 struct userdiff_driver *drv = userdiff_find_by_path(attr_path);
1990                 if (drv && drv->external)
1991                         pgm = drv->external;
1992         }
1993
1994         if (pgm) {
1995                 run_external_diff(pgm, name, other, one, two, xfrm_msg,
1996                                   complete_rewrite);
1997                 return;
1998         }
1999         if (one && two)
2000                 builtin_diff(name, other ? other : name,
2001                              one, two, xfrm_msg, o, complete_rewrite);
2002         else
2003                 fprintf(o->file, "* Unmerged path %s\n", name);
2004 }
2005
2006 static void diff_fill_sha1_info(struct diff_filespec *one)
2007 {
2008         if (DIFF_FILE_VALID(one)) {
2009                 if (!one->sha1_valid) {
2010                         struct stat st;
2011                         if (!strcmp(one->path, "-")) {
2012                                 hashcpy(one->sha1, null_sha1);
2013                                 return;
2014                         }
2015                         if (lstat(one->path, &st) < 0)
2016                                 die("stat %s", one->path);
2017                         if (index_path(one->sha1, one->path, &st, 0))
2018                                 die("cannot hash %s\n", one->path);
2019                 }
2020         }
2021         else
2022                 hashclr(one->sha1);
2023 }
2024
2025 static int similarity_index(struct diff_filepair *p)
2026 {
2027         return p->score * 100 / MAX_SCORE;
2028 }
2029
2030 static void strip_prefix(int prefix_length, const char **namep, const char **otherp)
2031 {
2032         /* Strip the prefix but do not molest /dev/null and absolute paths */
2033         if (*namep && **namep != '/')
2034                 *namep += prefix_length;
2035         if (*otherp && **otherp != '/')
2036                 *otherp += prefix_length;
2037 }
2038
2039 static void run_diff(struct diff_filepair *p, struct diff_options *o)
2040 {
2041         const char *pgm = external_diff();
2042         struct strbuf msg;
2043         char *xfrm_msg;
2044         struct diff_filespec *one = p->one;
2045         struct diff_filespec *two = p->two;
2046         const char *name;
2047         const char *other;
2048         const char *attr_path;
2049         int complete_rewrite = 0;
2050
2051         name  = p->one->path;
2052         other = (strcmp(name, p->two->path) ? p->two->path : NULL);
2053         attr_path = name;
2054         if (o->prefix_length)
2055                 strip_prefix(o->prefix_length, &name, &other);
2056
2057         if (DIFF_PAIR_UNMERGED(p)) {
2058                 run_diff_cmd(pgm, name, NULL, attr_path,
2059                              NULL, NULL, NULL, o, 0);
2060                 return;
2061         }
2062
2063         diff_fill_sha1_info(one);
2064         diff_fill_sha1_info(two);
2065
2066         strbuf_init(&msg, PATH_MAX * 2 + 300);
2067         switch (p->status) {
2068         case DIFF_STATUS_COPIED:
2069                 strbuf_addf(&msg, "similarity index %d%%", similarity_index(p));
2070                 strbuf_addstr(&msg, "\ncopy from ");
2071                 quote_c_style(name, &msg, NULL, 0);
2072                 strbuf_addstr(&msg, "\ncopy to ");
2073                 quote_c_style(other, &msg, NULL, 0);
2074                 strbuf_addch(&msg, '\n');
2075                 break;
2076         case DIFF_STATUS_RENAMED:
2077                 strbuf_addf(&msg, "similarity index %d%%", similarity_index(p));
2078                 strbuf_addstr(&msg, "\nrename from ");
2079                 quote_c_style(name, &msg, NULL, 0);
2080                 strbuf_addstr(&msg, "\nrename to ");
2081                 quote_c_style(other, &msg, NULL, 0);
2082                 strbuf_addch(&msg, '\n');
2083                 break;
2084         case DIFF_STATUS_MODIFIED:
2085                 if (p->score) {
2086                         strbuf_addf(&msg, "dissimilarity index %d%%\n",
2087                                         similarity_index(p));
2088                         complete_rewrite = 1;
2089                         break;
2090                 }
2091                 /* fallthru */
2092         default:
2093                 /* nothing */
2094                 ;
2095         }
2096
2097         if (hashcmp(one->sha1, two->sha1)) {
2098                 int abbrev = DIFF_OPT_TST(o, FULL_INDEX) ? 40 : DEFAULT_ABBREV;
2099
2100                 if (DIFF_OPT_TST(o, BINARY)) {
2101                         mmfile_t mf;
2102                         if ((!fill_mmfile(&mf, one) && diff_filespec_is_binary(one)) ||
2103                             (!fill_mmfile(&mf, two) && diff_filespec_is_binary(two)))
2104                                 abbrev = 40;
2105                 }
2106                 strbuf_addf(&msg, "index %.*s..%.*s",
2107                                 abbrev, sha1_to_hex(one->sha1),
2108                                 abbrev, sha1_to_hex(two->sha1));
2109                 if (one->mode == two->mode)
2110                         strbuf_addf(&msg, " %06o", one->mode);
2111                 strbuf_addch(&msg, '\n');
2112         }
2113
2114         if (msg.len)
2115                 strbuf_setlen(&msg, msg.len - 1);
2116         xfrm_msg = msg.len ? msg.buf : NULL;
2117
2118         if (!pgm &&
2119             DIFF_FILE_VALID(one) && DIFF_FILE_VALID(two) &&
2120             (S_IFMT & one->mode) != (S_IFMT & two->mode)) {
2121                 /* a filepair that changes between file and symlink
2122                  * needs to be split into deletion and creation.
2123                  */
2124                 struct diff_filespec *null = alloc_filespec(two->path);
2125                 run_diff_cmd(NULL, name, other, attr_path,
2126                              one, null, xfrm_msg, o, 0);
2127                 free(null);
2128                 null = alloc_filespec(one->path);
2129                 run_diff_cmd(NULL, name, other, attr_path,
2130                              null, two, xfrm_msg, o, 0);
2131                 free(null);
2132         }
2133         else
2134                 run_diff_cmd(pgm, name, other, attr_path,
2135                              one, two, xfrm_msg, o, complete_rewrite);
2136
2137         strbuf_release(&msg);
2138 }
2139
2140 static void run_diffstat(struct diff_filepair *p, struct diff_options *o,
2141                          struct diffstat_t *diffstat)
2142 {
2143         const char *name;
2144         const char *other;
2145         int complete_rewrite = 0;
2146
2147         if (DIFF_PAIR_UNMERGED(p)) {
2148                 /* unmerged */
2149                 builtin_diffstat(p->one->path, NULL, NULL, NULL, diffstat, o, 0);
2150                 return;
2151         }
2152
2153         name = p->one->path;
2154         other = (strcmp(name, p->two->path) ? p->two->path : NULL);
2155
2156         if (o->prefix_length)
2157                 strip_prefix(o->prefix_length, &name, &other);
2158
2159         diff_fill_sha1_info(p->one);
2160         diff_fill_sha1_info(p->two);
2161
2162         if (p->status == DIFF_STATUS_MODIFIED && p->score)
2163                 complete_rewrite = 1;
2164         builtin_diffstat(name, other, p->one, p->two, diffstat, o, complete_rewrite);
2165 }
2166
2167 static void run_checkdiff(struct diff_filepair *p, struct diff_options *o)
2168 {
2169         const char *name;
2170         const char *other;
2171         const char *attr_path;
2172
2173         if (DIFF_PAIR_UNMERGED(p)) {
2174                 /* unmerged */
2175                 return;
2176         }
2177
2178         name = p->one->path;
2179         other = (strcmp(name, p->two->path) ? p->two->path : NULL);
2180         attr_path = other ? other : name;
2181
2182         if (o->prefix_length)
2183                 strip_prefix(o->prefix_length, &name, &other);
2184
2185         diff_fill_sha1_info(p->one);
2186         diff_fill_sha1_info(p->two);
2187
2188         builtin_checkdiff(name, other, attr_path, p->one, p->two, o);
2189 }
2190
2191 void diff_setup(struct diff_options *options)
2192 {
2193         memset(options, 0, sizeof(*options));
2194
2195         options->file = stdout;
2196
2197         options->line_termination = '\n';
2198         options->break_opt = -1;
2199         options->rename_limit = -1;
2200         options->dirstat_percent = 3;
2201         DIFF_OPT_CLR(options, DIRSTAT_CUMULATIVE);
2202         options->context = 3;
2203
2204         options->change = diff_change;
2205         options->add_remove = diff_addremove;
2206         if (diff_use_color_default > 0)
2207                 DIFF_OPT_SET(options, COLOR_DIFF);
2208         else
2209                 DIFF_OPT_CLR(options, COLOR_DIFF);
2210         options->detect_rename = diff_detect_rename_default;
2211
2212         if (!diff_mnemonic_prefix) {
2213                 options->a_prefix = "a/";
2214                 options->b_prefix = "b/";
2215         }
2216 }
2217
2218 int diff_setup_done(struct diff_options *options)
2219 {
2220         int count = 0;
2221
2222         if (options->output_format & DIFF_FORMAT_NAME)
2223                 count++;
2224         if (options->output_format & DIFF_FORMAT_NAME_STATUS)
2225                 count++;
2226         if (options->output_format & DIFF_FORMAT_CHECKDIFF)
2227                 count++;
2228         if (options->output_format & DIFF_FORMAT_NO_OUTPUT)
2229                 count++;
2230         if (count > 1)
2231                 die("--name-only, --name-status, --check and -s are mutually exclusive");
2232
2233         if (DIFF_OPT_TST(options, FIND_COPIES_HARDER))
2234                 options->detect_rename = DIFF_DETECT_COPY;
2235
2236         if (!DIFF_OPT_TST(options, RELATIVE_NAME))
2237                 options->prefix = NULL;
2238         if (options->prefix)
2239                 options->prefix_length = strlen(options->prefix);
2240         else
2241                 options->prefix_length = 0;
2242
2243         if (options->output_format & (DIFF_FORMAT_NAME |
2244                                       DIFF_FORMAT_NAME_STATUS |
2245                                       DIFF_FORMAT_CHECKDIFF |
2246                                       DIFF_FORMAT_NO_OUTPUT))
2247                 options->output_format &= ~(DIFF_FORMAT_RAW |
2248                                             DIFF_FORMAT_NUMSTAT |
2249                                             DIFF_FORMAT_DIFFSTAT |
2250                                             DIFF_FORMAT_SHORTSTAT |
2251                                             DIFF_FORMAT_DIRSTAT |
2252                                             DIFF_FORMAT_SUMMARY |
2253                                             DIFF_FORMAT_PATCH);
2254
2255         /*
2256          * These cases always need recursive; we do not drop caller-supplied
2257          * recursive bits for other formats here.
2258          */
2259         if (options->output_format & (DIFF_FORMAT_PATCH |
2260                                       DIFF_FORMAT_NUMSTAT |
2261                                       DIFF_FORMAT_DIFFSTAT |
2262                                       DIFF_FORMAT_SHORTSTAT |
2263                                       DIFF_FORMAT_DIRSTAT |
2264                                       DIFF_FORMAT_SUMMARY |
2265                                       DIFF_FORMAT_CHECKDIFF))
2266                 DIFF_OPT_SET(options, RECURSIVE);
2267         /*
2268          * Also pickaxe would not work very well if you do not say recursive
2269          */
2270         if (options->pickaxe)
2271                 DIFF_OPT_SET(options, RECURSIVE);
2272
2273         if (options->detect_rename && options->rename_limit < 0)
2274                 options->rename_limit = diff_rename_limit_default;
2275         if (options->setup & DIFF_SETUP_USE_CACHE) {
2276                 if (!active_cache)
2277                         /* read-cache does not die even when it fails
2278                          * so it is safe for us to do this here.  Also
2279                          * it does not smudge active_cache or active_nr
2280                          * when it fails, so we do not have to worry about
2281                          * cleaning it up ourselves either.
2282                          */
2283                         read_cache();
2284         }
2285         if (options->abbrev <= 0 || 40 < options->abbrev)
2286                 options->abbrev = 40; /* full */
2287
2288         /*
2289          * It does not make sense to show the first hit we happened
2290          * to have found.  It does not make sense not to return with
2291          * exit code in such a case either.
2292          */
2293         if (DIFF_OPT_TST(options, QUIET)) {
2294                 options->output_format = DIFF_FORMAT_NO_OUTPUT;
2295                 DIFF_OPT_SET(options, EXIT_WITH_STATUS);
2296         }
2297
2298         return 0;
2299 }
2300
2301 static int opt_arg(const char *arg, int arg_short, const char *arg_long, int *val)
2302 {
2303         char c, *eq;
2304         int len;
2305
2306         if (*arg != '-')
2307                 return 0;
2308         c = *++arg;
2309         if (!c)
2310                 return 0;
2311         if (c == arg_short) {
2312                 c = *++arg;
2313                 if (!c)
2314                         return 1;
2315                 if (val && isdigit(c)) {
2316                         char *end;
2317                         int n = strtoul(arg, &end, 10);
2318                         if (*end)
2319                                 return 0;
2320                         *val = n;
2321                         return 1;
2322                 }
2323                 return 0;
2324         }
2325         if (c != '-')
2326                 return 0;
2327         arg++;
2328         eq = strchr(arg, '=');
2329         if (eq)
2330                 len = eq - arg;
2331         else
2332                 len = strlen(arg);
2333         if (!len || strncmp(arg, arg_long, len))
2334                 return 0;
2335         if (eq) {
2336                 int n;
2337                 char *end;
2338                 if (!isdigit(*++eq))
2339                         return 0;
2340                 n = strtoul(eq, &end, 10);
2341                 if (*end)
2342                         return 0;
2343                 *val = n;
2344         }
2345         return 1;
2346 }
2347
2348 static int diff_scoreopt_parse(const char *opt);
2349
2350 int diff_opt_parse(struct diff_options *options, const char **av, int ac)
2351 {
2352         const char *arg = av[0];
2353
2354         /* Output format options */
2355         if (!strcmp(arg, "-p") || !strcmp(arg, "-u"))
2356                 options->output_format |= DIFF_FORMAT_PATCH;
2357         else if (opt_arg(arg, 'U', "unified", &options->context))
2358                 options->output_format |= DIFF_FORMAT_PATCH;
2359         else if (!strcmp(arg, "--raw"))
2360                 options->output_format |= DIFF_FORMAT_RAW;
2361         else if (!strcmp(arg, "--patch-with-raw"))
2362                 options->output_format |= DIFF_FORMAT_PATCH | DIFF_FORMAT_RAW;
2363         else if (!strcmp(arg, "--numstat"))
2364                 options->output_format |= DIFF_FORMAT_NUMSTAT;
2365         else if (!strcmp(arg, "--shortstat"))
2366                 options->output_format |= DIFF_FORMAT_SHORTSTAT;
2367         else if (opt_arg(arg, 'X', "dirstat", &options->dirstat_percent))
2368                 options->output_format |= DIFF_FORMAT_DIRSTAT;
2369         else if (!strcmp(arg, "--cumulative")) {
2370                 options->output_format |= DIFF_FORMAT_DIRSTAT;
2371                 DIFF_OPT_SET(options, DIRSTAT_CUMULATIVE);
2372         } else if (opt_arg(arg, 0, "dirstat-by-file",
2373                            &options->dirstat_percent)) {
2374                 options->output_format |= DIFF_FORMAT_DIRSTAT;
2375                 DIFF_OPT_SET(options, DIRSTAT_BY_FILE);
2376         }
2377         else if (!strcmp(arg, "--check"))
2378                 options->output_format |= DIFF_FORMAT_CHECKDIFF;
2379         else if (!strcmp(arg, "--summary"))
2380                 options->output_format |= DIFF_FORMAT_SUMMARY;
2381         else if (!strcmp(arg, "--patch-with-stat"))
2382                 options->output_format |= DIFF_FORMAT_PATCH | DIFF_FORMAT_DIFFSTAT;
2383         else if (!strcmp(arg, "--name-only"))
2384                 options->output_format |= DIFF_FORMAT_NAME;
2385         else if (!strcmp(arg, "--name-status"))
2386                 options->output_format |= DIFF_FORMAT_NAME_STATUS;
2387         else if (!strcmp(arg, "-s"))
2388                 options->output_format |= DIFF_FORMAT_NO_OUTPUT;
2389         else if (!prefixcmp(arg, "--stat")) {
2390                 char *end;
2391                 int width = options->stat_width;
2392                 int name_width = options->stat_name_width;
2393                 arg += 6;
2394                 end = (char *)arg;
2395
2396                 switch (*arg) {
2397                 case '-':
2398                         if (!prefixcmp(arg, "-width="))
2399                                 width = strtoul(arg + 7, &end, 10);
2400                         else if (!prefixcmp(arg, "-name-width="))
2401                                 name_width = strtoul(arg + 12, &end, 10);
2402                         break;
2403                 case '=':
2404                         width = strtoul(arg+1, &end, 10);
2405                         if (*end == ',')
2406                                 name_width = strtoul(end+1, &end, 10);
2407                 }
2408
2409                 /* Important! This checks all the error cases! */
2410                 if (*end)
2411                         return 0;
2412                 options->output_format |= DIFF_FORMAT_DIFFSTAT;
2413                 options->stat_name_width = name_width;
2414                 options->stat_width = width;
2415         }
2416
2417         /* renames options */
2418         else if (!prefixcmp(arg, "-B")) {
2419                 if ((options->break_opt = diff_scoreopt_parse(arg)) == -1)
2420                         return -1;
2421         }
2422         else if (!prefixcmp(arg, "-M")) {
2423                 if ((options->rename_score = diff_scoreopt_parse(arg)) == -1)
2424                         return -1;
2425                 options->detect_rename = DIFF_DETECT_RENAME;
2426         }
2427         else if (!prefixcmp(arg, "-C")) {
2428                 if (options->detect_rename == DIFF_DETECT_COPY)
2429                         DIFF_OPT_SET(options, FIND_COPIES_HARDER);
2430                 if ((options->rename_score = diff_scoreopt_parse(arg)) == -1)
2431                         return -1;
2432                 options->detect_rename = DIFF_DETECT_COPY;
2433         }
2434         else if (!strcmp(arg, "--no-renames"))
2435                 options->detect_rename = 0;
2436         else if (!strcmp(arg, "--relative"))
2437                 DIFF_OPT_SET(options, RELATIVE_NAME);
2438         else if (!prefixcmp(arg, "--relative=")) {
2439                 DIFF_OPT_SET(options, RELATIVE_NAME);
2440                 options->prefix = arg + 11;
2441         }
2442
2443         /* xdiff options */
2444         else if (!strcmp(arg, "-w") || !strcmp(arg, "--ignore-all-space"))
2445                 options->xdl_opts |= XDF_IGNORE_WHITESPACE;
2446         else if (!strcmp(arg, "-b") || !strcmp(arg, "--ignore-space-change"))
2447                 options->xdl_opts |= XDF_IGNORE_WHITESPACE_CHANGE;
2448         else if (!strcmp(arg, "--ignore-space-at-eol"))
2449                 options->xdl_opts |= XDF_IGNORE_WHITESPACE_AT_EOL;
2450
2451         /* flags options */
2452         else if (!strcmp(arg, "--binary")) {
2453                 options->output_format |= DIFF_FORMAT_PATCH;
2454                 DIFF_OPT_SET(options, BINARY);
2455         }
2456         else if (!strcmp(arg, "--full-index"))
2457                 DIFF_OPT_SET(options, FULL_INDEX);
2458         else if (!strcmp(arg, "-a") || !strcmp(arg, "--text"))
2459                 DIFF_OPT_SET(options, TEXT);
2460         else if (!strcmp(arg, "-R"))
2461                 DIFF_OPT_SET(options, REVERSE_DIFF);
2462         else if (!strcmp(arg, "--find-copies-harder"))
2463                 DIFF_OPT_SET(options, FIND_COPIES_HARDER);
2464         else if (!strcmp(arg, "--follow"))
2465                 DIFF_OPT_SET(options, FOLLOW_RENAMES);
2466         else if (!strcmp(arg, "--color"))
2467                 DIFF_OPT_SET(options, COLOR_DIFF);
2468         else if (!strcmp(arg, "--no-color"))
2469                 DIFF_OPT_CLR(options, COLOR_DIFF);
2470         else if (!strcmp(arg, "--color-words"))
2471                 options->flags |= DIFF_OPT_COLOR_DIFF | DIFF_OPT_COLOR_DIFF_WORDS;
2472         else if (!strcmp(arg, "--exit-code"))
2473                 DIFF_OPT_SET(options, EXIT_WITH_STATUS);
2474         else if (!strcmp(arg, "--quiet"))
2475                 DIFF_OPT_SET(options, QUIET);
2476         else if (!strcmp(arg, "--ext-diff"))
2477                 DIFF_OPT_SET(options, ALLOW_EXTERNAL);
2478         else if (!strcmp(arg, "--no-ext-diff"))
2479                 DIFF_OPT_CLR(options, ALLOW_EXTERNAL);
2480         else if (!strcmp(arg, "--ignore-submodules"))
2481                 DIFF_OPT_SET(options, IGNORE_SUBMODULES);
2482
2483         /* misc options */
2484         else if (!strcmp(arg, "-z"))
2485                 options->line_termination = 0;
2486         else if (!prefixcmp(arg, "-l"))
2487                 options->rename_limit = strtoul(arg+2, NULL, 10);
2488         else if (!prefixcmp(arg, "-S"))
2489                 options->pickaxe = arg + 2;
2490         else if (!strcmp(arg, "--pickaxe-all"))
2491                 options->pickaxe_opts = DIFF_PICKAXE_ALL;
2492         else if (!strcmp(arg, "--pickaxe-regex"))
2493                 options->pickaxe_opts = DIFF_PICKAXE_REGEX;
2494         else if (!prefixcmp(arg, "-O"))
2495                 options->orderfile = arg + 2;
2496         else if (!prefixcmp(arg, "--diff-filter="))
2497                 options->filter = arg + 14;
2498         else if (!strcmp(arg, "--abbrev"))
2499                 options->abbrev = DEFAULT_ABBREV;
2500         else if (!prefixcmp(arg, "--abbrev=")) {
2501                 options->abbrev = strtoul(arg + 9, NULL, 10);
2502                 if (options->abbrev < MINIMUM_ABBREV)
2503                         options->abbrev = MINIMUM_ABBREV;
2504                 else if (40 < options->abbrev)
2505                         options->abbrev = 40;
2506         }
2507         else if (!prefixcmp(arg, "--src-prefix="))
2508                 options->a_prefix = arg + 13;
2509         else if (!prefixcmp(arg, "--dst-prefix="))
2510                 options->b_prefix = arg + 13;
2511         else if (!strcmp(arg, "--no-prefix"))
2512                 options->a_prefix = options->b_prefix = "";
2513         else if (!prefixcmp(arg, "--output=")) {
2514                 options->file = fopen(arg + strlen("--output="), "w");
2515                 options->close_file = 1;
2516         } else
2517                 return 0;
2518         return 1;
2519 }
2520
2521 static int parse_num(const char **cp_p)
2522 {
2523         unsigned long num, scale;
2524         int ch, dot;
2525         const char *cp = *cp_p;
2526
2527         num = 0;
2528         scale = 1;
2529         dot = 0;
2530         for(;;) {
2531                 ch = *cp;
2532                 if ( !dot && ch == '.' ) {
2533                         scale = 1;
2534                         dot = 1;
2535                 } else if ( ch == '%' ) {
2536                         scale = dot ? scale*100 : 100;
2537                         cp++;   /* % is always at the end */
2538                         break;
2539                 } else if ( ch >= '0' && ch <= '9' ) {
2540                         if ( scale < 100000 ) {
2541                                 scale *= 10;
2542                                 num = (num*10) + (ch-'0');
2543                         }
2544                 } else {
2545                         break;
2546                 }
2547                 cp++;
2548         }
2549         *cp_p = cp;
2550
2551         /* user says num divided by scale and we say internally that
2552          * is MAX_SCORE * num / scale.
2553          */
2554         return (int)((num >= scale) ? MAX_SCORE : (MAX_SCORE * num / scale));
2555 }
2556
2557 static int diff_scoreopt_parse(const char *opt)
2558 {
2559         int opt1, opt2, cmd;
2560
2561         if (*opt++ != '-')
2562                 return -1;
2563         cmd = *opt++;
2564         if (cmd != 'M' && cmd != 'C' && cmd != 'B')
2565                 return -1; /* that is not a -M, -C nor -B option */
2566
2567         opt1 = parse_num(&opt);
2568         if (cmd != 'B')
2569                 opt2 = 0;
2570         else {
2571                 if (*opt == 0)
2572                         opt2 = 0;
2573                 else if (*opt != '/')
2574                         return -1; /* we expect -B80/99 or -B80 */
2575                 else {
2576                         opt++;
2577                         opt2 = parse_num(&opt);
2578                 }
2579         }
2580         if (*opt != 0)
2581                 return -1;
2582         return opt1 | (opt2 << 16);
2583 }
2584
2585 struct diff_queue_struct diff_queued_diff;
2586
2587 void diff_q(struct diff_queue_struct *queue, struct diff_filepair *dp)
2588 {
2589         if (queue->alloc <= queue->nr) {
2590                 queue->alloc = alloc_nr(queue->alloc);
2591                 queue->queue = xrealloc(queue->queue,
2592                                         sizeof(dp) * queue->alloc);
2593         }
2594         queue->queue[queue->nr++] = dp;
2595 }
2596
2597 struct diff_filepair *diff_queue(struct diff_queue_struct *queue,
2598                                  struct diff_filespec *one,
2599                                  struct diff_filespec *two)
2600 {
2601         struct diff_filepair *dp = xcalloc(1, sizeof(*dp));
2602         dp->one = one;
2603         dp->two = two;
2604         if (queue)
2605                 diff_q(queue, dp);
2606         return dp;
2607 }
2608
2609 void diff_free_filepair(struct diff_filepair *p)
2610 {
2611         free_filespec(p->one);
2612         free_filespec(p->two);
2613         free(p);
2614 }
2615
2616 /* This is different from find_unique_abbrev() in that
2617  * it stuffs the result with dots for alignment.
2618  */
2619 const char *diff_unique_abbrev(const unsigned char *sha1, int len)
2620 {
2621         int abblen;
2622         const char *abbrev;
2623         if (len == 40)
2624                 return sha1_to_hex(sha1);
2625
2626         abbrev = find_unique_abbrev(sha1, len);
2627         abblen = strlen(abbrev);
2628         if (abblen < 37) {
2629                 static char hex[41];
2630                 if (len < abblen && abblen <= len + 2)
2631                         sprintf(hex, "%s%.*s", abbrev, len+3-abblen, "..");
2632                 else
2633                         sprintf(hex, "%s...", abbrev);
2634                 return hex;
2635         }
2636         return sha1_to_hex(sha1);
2637 }
2638
2639 static void diff_flush_raw(struct diff_filepair *p, struct diff_options *opt)
2640 {
2641         int line_termination = opt->line_termination;
2642         int inter_name_termination = line_termination ? '\t' : '\0';
2643
2644         if (!(opt->output_format & DIFF_FORMAT_NAME_STATUS)) {
2645                 fprintf(opt->file, ":%06o %06o %s ", p->one->mode, p->two->mode,
2646                         diff_unique_abbrev(p->one->sha1, opt->abbrev));
2647                 fprintf(opt->file, "%s ", diff_unique_abbrev(p->two->sha1, opt->abbrev));
2648         }
2649         if (p->score) {
2650                 fprintf(opt->file, "%c%03d%c", p->status, similarity_index(p),
2651                         inter_name_termination);
2652         } else {
2653                 fprintf(opt->file, "%c%c", p->status, inter_name_termination);
2654         }
2655
2656         if (p->status == DIFF_STATUS_COPIED ||
2657             p->status == DIFF_STATUS_RENAMED) {
2658                 const char *name_a, *name_b;
2659                 name_a = p->one->path;
2660                 name_b = p->two->path;
2661                 strip_prefix(opt->prefix_length, &name_a, &name_b);
2662                 write_name_quoted(name_a, opt->file, inter_name_termination);
2663                 write_name_quoted(name_b, opt->file, line_termination);
2664         } else {
2665                 const char *name_a, *name_b;
2666                 name_a = p->one->mode ? p->one->path : p->two->path;
2667                 name_b = NULL;
2668                 strip_prefix(opt->prefix_length, &name_a, &name_b);
2669                 write_name_quoted(name_a, opt->file, line_termination);
2670         }
2671 }
2672
2673 int diff_unmodified_pair(struct diff_filepair *p)
2674 {
2675         /* This function is written stricter than necessary to support
2676          * the currently implemented transformers, but the idea is to
2677          * let transformers to produce diff_filepairs any way they want,
2678          * and filter and clean them up here before producing the output.
2679          */
2680         struct diff_filespec *one = p->one, *two = p->two;
2681
2682         if (DIFF_PAIR_UNMERGED(p))
2683                 return 0; /* unmerged is interesting */
2684
2685         /* deletion, addition, mode or type change
2686          * and rename are all interesting.
2687          */
2688         if (DIFF_FILE_VALID(one) != DIFF_FILE_VALID(two) ||
2689             DIFF_PAIR_MODE_CHANGED(p) ||
2690             strcmp(one->path, two->path))
2691                 return 0;
2692
2693         /* both are valid and point at the same path.  that is, we are
2694          * dealing with a change.
2695          */
2696         if (one->sha1_valid && two->sha1_valid &&
2697             !hashcmp(one->sha1, two->sha1))
2698                 return 1; /* no change */
2699         if (!one->sha1_valid && !two->sha1_valid)
2700                 return 1; /* both look at the same file on the filesystem. */
2701         return 0;
2702 }
2703
2704 static void diff_flush_patch(struct diff_filepair *p, struct diff_options *o)
2705 {
2706         if (diff_unmodified_pair(p))
2707                 return;
2708
2709         if ((DIFF_FILE_VALID(p->one) && S_ISDIR(p->one->mode)) ||
2710             (DIFF_FILE_VALID(p->two) && S_ISDIR(p->two->mode)))
2711                 return; /* no tree diffs in patch format */
2712
2713         run_diff(p, o);
2714 }
2715
2716 static void diff_flush_stat(struct diff_filepair *p, struct diff_options *o,
2717                             struct diffstat_t *diffstat)
2718 {
2719         if (diff_unmodified_pair(p))
2720                 return;
2721
2722         if ((DIFF_FILE_VALID(p->one) && S_ISDIR(p->one->mode)) ||
2723             (DIFF_FILE_VALID(p->two) && S_ISDIR(p->two->mode)))
2724                 return; /* no tree diffs in patch format */
2725
2726         run_diffstat(p, o, diffstat);
2727 }
2728
2729 static void diff_flush_checkdiff(struct diff_filepair *p,
2730                 struct diff_options *o)
2731 {
2732         if (diff_unmodified_pair(p))
2733                 return;
2734
2735         if ((DIFF_FILE_VALID(p->one) && S_ISDIR(p->one->mode)) ||
2736             (DIFF_FILE_VALID(p->two) && S_ISDIR(p->two->mode)))
2737                 return; /* no tree diffs in patch format */
2738
2739         run_checkdiff(p, o);
2740 }
2741
2742 int diff_queue_is_empty(void)
2743 {
2744         struct diff_queue_struct *q = &diff_queued_diff;
2745         int i;
2746         for (i = 0; i < q->nr; i++)
2747                 if (!diff_unmodified_pair(q->queue[i]))
2748                         return 0;
2749         return 1;
2750 }
2751
2752 #if DIFF_DEBUG
2753 void diff_debug_filespec(struct diff_filespec *s, int x, const char *one)
2754 {
2755         fprintf(stderr, "queue[%d] %s (%s) %s %06o %s\n",
2756                 x, one ? one : "",
2757                 s->path,
2758                 DIFF_FILE_VALID(s) ? "valid" : "invalid",
2759                 s->mode,
2760                 s->sha1_valid ? sha1_to_hex(s->sha1) : "");
2761         fprintf(stderr, "queue[%d] %s size %lu flags %d\n",
2762                 x, one ? one : "",
2763                 s->size, s->xfrm_flags);
2764 }
2765
2766 void diff_debug_filepair(const struct diff_filepair *p, int i)
2767 {
2768         diff_debug_filespec(p->one, i, "one");
2769         diff_debug_filespec(p->two, i, "two");
2770         fprintf(stderr, "score %d, status %c rename_used %d broken %d\n",
2771                 p->score, p->status ? p->status : '?',
2772                 p->one->rename_used, p->broken_pair);
2773 }
2774
2775 void diff_debug_queue(const char *msg, struct diff_queue_struct *q)
2776 {
2777         int i;
2778         if (msg)
2779                 fprintf(stderr, "%s\n", msg);
2780         fprintf(stderr, "q->nr = %d\n", q->nr);
2781         for (i = 0; i < q->nr; i++) {
2782                 struct diff_filepair *p = q->queue[i];
2783                 diff_debug_filepair(p, i);
2784         }
2785 }
2786 #endif
2787
2788 static void diff_resolve_rename_copy(void)
2789 {
2790         int i;
2791         struct diff_filepair *p;
2792         struct diff_queue_struct *q = &diff_queued_diff;
2793
2794         diff_debug_queue("resolve-rename-copy", q);
2795
2796         for (i = 0; i < q->nr; i++) {
2797                 p = q->queue[i];
2798                 p->status = 0; /* undecided */
2799                 if (DIFF_PAIR_UNMERGED(p))
2800                         p->status = DIFF_STATUS_UNMERGED;
2801                 else if (!DIFF_FILE_VALID(p->one))
2802                         p->status = DIFF_STATUS_ADDED;
2803                 else if (!DIFF_FILE_VALID(p->two))
2804                         p->status = DIFF_STATUS_DELETED;
2805                 else if (DIFF_PAIR_TYPE_CHANGED(p))
2806                         p->status = DIFF_STATUS_TYPE_CHANGED;
2807
2808                 /* from this point on, we are dealing with a pair
2809                  * whose both sides are valid and of the same type, i.e.
2810                  * either in-place edit or rename/copy edit.
2811                  */
2812                 else if (DIFF_PAIR_RENAME(p)) {
2813                         /*
2814                          * A rename might have re-connected a broken
2815                          * pair up, causing the pathnames to be the
2816                          * same again. If so, that's not a rename at
2817                          * all, just a modification..
2818                          *
2819                          * Otherwise, see if this source was used for
2820                          * multiple renames, in which case we decrement
2821                          * the count, and call it a copy.
2822                          */
2823                         if (!strcmp(p->one->path, p->two->path))
2824                                 p->status = DIFF_STATUS_MODIFIED;
2825                         else if (--p->one->rename_used > 0)
2826                                 p->status = DIFF_STATUS_COPIED;
2827                         else
2828                                 p->status = DIFF_STATUS_RENAMED;
2829                 }
2830                 else if (hashcmp(p->one->sha1, p->two->sha1) ||
2831                          p->one->mode != p->two->mode ||
2832                          is_null_sha1(p->one->sha1))
2833                         p->status = DIFF_STATUS_MODIFIED;
2834                 else {
2835                         /* This is a "no-change" entry and should not
2836                          * happen anymore, but prepare for broken callers.
2837                          */
2838                         error("feeding unmodified %s to diffcore",
2839                               p->one->path);
2840                         p->status = DIFF_STATUS_UNKNOWN;
2841                 }
2842         }
2843         diff_debug_queue("resolve-rename-copy done", q);
2844 }
2845
2846 static int check_pair_status(struct diff_filepair *p)
2847 {
2848         switch (p->status) {
2849         case DIFF_STATUS_UNKNOWN:
2850                 return 0;
2851         case 0:
2852                 die("internal error in diff-resolve-rename-copy");
2853         default:
2854                 return 1;
2855         }
2856 }
2857
2858 static void flush_one_pair(struct diff_filepair *p, struct diff_options *opt)
2859 {
2860         int fmt = opt->output_format;
2861
2862         if (fmt & DIFF_FORMAT_CHECKDIFF)
2863                 diff_flush_checkdiff(p, opt);
2864         else if (fmt & (DIFF_FORMAT_RAW | DIFF_FORMAT_NAME_STATUS))
2865                 diff_flush_raw(p, opt);
2866         else if (fmt & DIFF_FORMAT_NAME) {
2867                 const char *name_a, *name_b;
2868                 name_a = p->two->path;
2869                 name_b = NULL;
2870                 strip_prefix(opt->prefix_length, &name_a, &name_b);
2871                 write_name_quoted(name_a, opt->file, opt->line_termination);
2872         }
2873 }
2874
2875 static void show_file_mode_name(FILE *file, const char *newdelete, struct diff_filespec *fs)
2876 {
2877         if (fs->mode)
2878                 fprintf(file, " %s mode %06o ", newdelete, fs->mode);
2879         else
2880                 fprintf(file, " %s ", newdelete);
2881         write_name_quoted(fs->path, file, '\n');
2882 }
2883
2884
2885 static void show_mode_change(FILE *file, struct diff_filepair *p, int show_name)
2886 {
2887         if (p->one->mode && p->two->mode && p->one->mode != p->two->mode) {
2888                 fprintf(file, " mode change %06o => %06o%c", p->one->mode, p->two->mode,
2889                         show_name ? ' ' : '\n');
2890                 if (show_name) {
2891                         write_name_quoted(p->two->path, file, '\n');
2892                 }
2893         }
2894 }
2895
2896 static void show_rename_copy(FILE *file, const char *renamecopy, struct diff_filepair *p)
2897 {
2898         char *names = pprint_rename(p->one->path, p->two->path);
2899
2900         fprintf(file, " %s %s (%d%%)\n", renamecopy, names, similarity_index(p));
2901         free(names);
2902         show_mode_change(file, p, 0);
2903 }
2904
2905 static void diff_summary(FILE *file, struct diff_filepair *p)
2906 {
2907         switch(p->status) {
2908         case DIFF_STATUS_DELETED:
2909                 show_file_mode_name(file, "delete", p->one);
2910                 break;
2911         case DIFF_STATUS_ADDED:
2912                 show_file_mode_name(file, "create", p->two);
2913                 break;
2914         case DIFF_STATUS_COPIED:
2915                 show_rename_copy(file, "copy", p);
2916                 break;
2917         case DIFF_STATUS_RENAMED:
2918                 show_rename_copy(file, "rename", p);
2919                 break;
2920         default:
2921                 if (p->score) {
2922                         fputs(" rewrite ", file);
2923                         write_name_quoted(p->two->path, file, ' ');
2924                         fprintf(file, "(%d%%)\n", similarity_index(p));
2925                 }
2926                 show_mode_change(file, p, !p->score);
2927                 break;
2928         }
2929 }
2930
2931 struct patch_id_t {
2932         git_SHA_CTX *ctx;
2933         int patchlen;
2934 };
2935
2936 static int remove_space(char *line, int len)
2937 {
2938         int i;
2939         char *dst = line;
2940         unsigned char c;
2941
2942         for (i = 0; i < len; i++)
2943                 if (!isspace((c = line[i])))
2944                         *dst++ = c;
2945
2946         return dst - line;
2947 }
2948
2949 static void patch_id_consume(void *priv, char *line, unsigned long len)
2950 {
2951         struct patch_id_t *data = priv;
2952         int new_len;
2953
2954         /* Ignore line numbers when computing the SHA1 of the patch */
2955         if (!prefixcmp(line, "@@ -"))
2956                 return;
2957
2958         new_len = remove_space(line, len);
2959
2960         git_SHA1_Update(data->ctx, line, new_len);
2961         data->patchlen += new_len;
2962 }
2963
2964 /* returns 0 upon success, and writes result into sha1 */
2965 static int diff_get_patch_id(struct diff_options *options, unsigned char *sha1)
2966 {
2967         struct diff_queue_struct *q = &diff_queued_diff;
2968         int i;
2969         git_SHA_CTX ctx;
2970         struct patch_id_t data;
2971         char buffer[PATH_MAX * 4 + 20];
2972
2973         git_SHA1_Init(&ctx);
2974         memset(&data, 0, sizeof(struct patch_id_t));
2975         data.ctx = &ctx;
2976
2977         for (i = 0; i < q->nr; i++) {
2978                 xpparam_t xpp;
2979                 xdemitconf_t xecfg;
2980                 xdemitcb_t ecb;
2981                 mmfile_t mf1, mf2;
2982                 struct diff_filepair *p = q->queue[i];
2983                 int len1, len2;
2984
2985                 memset(&xpp, 0, sizeof(xpp));
2986                 memset(&xecfg, 0, sizeof(xecfg));
2987                 if (p->status == 0)
2988                         return error("internal diff status error");
2989                 if (p->status == DIFF_STATUS_UNKNOWN)
2990                         continue;
2991                 if (diff_unmodified_pair(p))
2992                         continue;
2993                 if ((DIFF_FILE_VALID(p->one) && S_ISDIR(p->one->mode)) ||
2994                     (DIFF_FILE_VALID(p->two) && S_ISDIR(p->two->mode)))
2995                         continue;
2996                 if (DIFF_PAIR_UNMERGED(p))
2997                         continue;
2998
2999                 diff_fill_sha1_info(p->one);
3000                 diff_fill_sha1_info(p->two);
3001                 if (fill_mmfile(&mf1, p->one) < 0 ||
3002                                 fill_mmfile(&mf2, p->two) < 0)
3003                         return error("unable to read files to diff");
3004
3005                 len1 = remove_space(p->one->path, strlen(p->one->path));
3006                 len2 = remove_space(p->two->path, strlen(p->two->path));
3007                 if (p->one->mode == 0)
3008                         len1 = snprintf(buffer, sizeof(buffer),
3009                                         "diff--gita/%.*sb/%.*s"
3010                                         "newfilemode%06o"
3011                                         "---/dev/null"
3012                                         "+++b/%.*s",
3013                                         len1, p->one->path,
3014                                         len2, p->two->path,
3015                                         p->two->mode,
3016                                         len2, p->two->path);
3017                 else if (p->two->mode == 0)
3018                         len1 = snprintf(buffer, sizeof(buffer),
3019                                         "diff--gita/%.*sb/%.*s"
3020                                         "deletedfilemode%06o"
3021                                         "---a/%.*s"
3022                                         "+++/dev/null",
3023                                         len1, p->one->path,
3024                                         len2, p->two->path,
3025                                         p->one->mode,
3026                                         len1, p->one->path);
3027                 else
3028                         len1 = snprintf(buffer, sizeof(buffer),
3029                                         "diff--gita/%.*sb/%.*s"
3030                                         "---a/%.*s"
3031                                         "+++b/%.*s",
3032                                         len1, p->one->path,
3033                                         len2, p->two->path,
3034                                         len1, p->one->path,
3035                                         len2, p->two->path);
3036                 git_SHA1_Update(&ctx, buffer, len1);
3037
3038                 xpp.flags = XDF_NEED_MINIMAL;
3039                 xecfg.ctxlen = 3;
3040                 xecfg.flags = XDL_EMIT_FUNCNAMES;
3041                 xdi_diff_outf(&mf1, &mf2, patch_id_consume, &data,
3042                               &xpp, &xecfg, &ecb);
3043         }
3044
3045         git_SHA1_Final(sha1, &ctx);
3046         return 0;
3047 }
3048
3049 int diff_flush_patch_id(struct diff_options *options, unsigned char *sha1)
3050 {
3051         struct diff_queue_struct *q = &diff_queued_diff;
3052         int i;
3053         int result = diff_get_patch_id(options, sha1);
3054
3055         for (i = 0; i < q->nr; i++)
3056                 diff_free_filepair(q->queue[i]);
3057
3058         free(q->queue);
3059         q->queue = NULL;
3060         q->nr = q->alloc = 0;
3061
3062         return result;
3063 }
3064
3065 static int is_summary_empty(const struct diff_queue_struct *q)
3066 {
3067         int i;
3068
3069         for (i = 0; i < q->nr; i++) {
3070                 const struct diff_filepair *p = q->queue[i];
3071
3072                 switch (p->status) {
3073                 case DIFF_STATUS_DELETED:
3074                 case DIFF_STATUS_ADDED:
3075                 case DIFF_STATUS_COPIED:
3076                 case DIFF_STATUS_RENAMED:
3077                         return 0;
3078                 default:
3079                         if (p->score)
3080                                 return 0;
3081                         if (p->one->mode && p->two->mode &&
3082                             p->one->mode != p->two->mode)
3083                                 return 0;
3084                         break;
3085                 }
3086         }
3087         return 1;
3088 }
3089
3090 void diff_flush(struct diff_options *options)
3091 {
3092         struct diff_queue_struct *q = &diff_queued_diff;
3093         int i, output_format = options->output_format;
3094         int separator = 0;
3095
3096         /*
3097          * Order: raw, stat, summary, patch
3098          * or:    name/name-status/checkdiff (other bits clear)
3099          */
3100         if (!q->nr)
3101                 goto free_queue;
3102
3103         if (output_format & (DIFF_FORMAT_RAW |
3104                              DIFF_FORMAT_NAME |
3105                              DIFF_FORMAT_NAME_STATUS |
3106                              DIFF_FORMAT_CHECKDIFF)) {
3107                 for (i = 0; i < q->nr; i++) {
3108                         struct diff_filepair *p = q->queue[i];
3109                         if (check_pair_status(p))
3110                                 flush_one_pair(p, options);
3111                 }
3112                 separator++;
3113         }
3114
3115         if (output_format & (DIFF_FORMAT_DIFFSTAT|DIFF_FORMAT_SHORTSTAT|DIFF_FORMAT_NUMSTAT)) {
3116                 struct diffstat_t diffstat;
3117
3118                 memset(&diffstat, 0, sizeof(struct diffstat_t));
3119                 for (i = 0; i < q->nr; i++) {
3120                         struct diff_filepair *p = q->queue[i];
3121                         if (check_pair_status(p))
3122                                 diff_flush_stat(p, options, &diffstat);
3123                 }
3124                 if (output_format & DIFF_FORMAT_NUMSTAT)
3125                         show_numstat(&diffstat, options);
3126                 if (output_format & DIFF_FORMAT_DIFFSTAT)
3127                         show_stats(&diffstat, options);
3128                 if (output_format & DIFF_FORMAT_SHORTSTAT)
3129                         show_shortstats(&diffstat, options);
3130                 free_diffstat_info(&diffstat);
3131                 separator++;
3132         }
3133         if (output_format & DIFF_FORMAT_DIRSTAT)
3134                 show_dirstat(options);
3135
3136         if (output_format & DIFF_FORMAT_SUMMARY && !is_summary_empty(q)) {
3137                 for (i = 0; i < q->nr; i++)
3138                         diff_summary(options->file, q->queue[i]);
3139                 separator++;
3140         }
3141
3142         if (output_format & DIFF_FORMAT_PATCH) {
3143                 if (separator) {
3144                         putc(options->line_termination, options->file);
3145                         if (options->stat_sep) {
3146                                 /* attach patch instead of inline */
3147                                 fputs(options->stat_sep, options->file);
3148                         }
3149                 }
3150
3151                 for (i = 0; i < q->nr; i++) {
3152                         struct diff_filepair *p = q->queue[i];
3153                         if (check_pair_status(p))
3154                                 diff_flush_patch(p, options);
3155                 }
3156         }
3157
3158         if (output_format & DIFF_FORMAT_CALLBACK)
3159                 options->format_callback(q, options, options->format_callback_data);
3160
3161         for (i = 0; i < q->nr; i++)
3162                 diff_free_filepair(q->queue[i]);
3163 free_queue:
3164         free(q->queue);
3165         q->queue = NULL;
3166         q->nr = q->alloc = 0;
3167         if (options->close_file)
3168                 fclose(options->file);
3169 }
3170
3171 static void diffcore_apply_filter(const char *filter)
3172 {
3173         int i;
3174         struct diff_queue_struct *q = &diff_queued_diff;
3175         struct diff_queue_struct outq;
3176         outq.queue = NULL;
3177         outq.nr = outq.alloc = 0;
3178
3179         if (!filter)
3180                 return;
3181
3182         if (strchr(filter, DIFF_STATUS_FILTER_AON)) {
3183                 int found;
3184                 for (i = found = 0; !found && i < q->nr; i++) {
3185                         struct diff_filepair *p = q->queue[i];
3186                         if (((p->status == DIFF_STATUS_MODIFIED) &&
3187                              ((p->score &&
3188                                strchr(filter, DIFF_STATUS_FILTER_BROKEN)) ||
3189                               (!p->score &&
3190                                strchr(filter, DIFF_STATUS_MODIFIED)))) ||
3191                             ((p->status != DIFF_STATUS_MODIFIED) &&
3192                              strchr(filter, p->status)))
3193                                 found++;
3194                 }
3195                 if (found)
3196                         return;
3197
3198                 /* otherwise we will clear the whole queue
3199                  * by copying the empty outq at the end of this
3200                  * function, but first clear the current entries
3201                  * in the queue.
3202                  */
3203                 for (i = 0; i < q->nr; i++)
3204                         diff_free_filepair(q->queue[i]);
3205         }
3206         else {
3207                 /* Only the matching ones */
3208                 for (i = 0; i < q->nr; i++) {
3209                         struct diff_filepair *p = q->queue[i];
3210
3211                         if (((p->status == DIFF_STATUS_MODIFIED) &&
3212                              ((p->score &&
3213                                strchr(filter, DIFF_STATUS_FILTER_BROKEN)) ||
3214                               (!p->score &&
3215                                strchr(filter, DIFF_STATUS_MODIFIED)))) ||
3216                             ((p->status != DIFF_STATUS_MODIFIED) &&
3217                              strchr(filter, p->status)))
3218                                 diff_q(&outq, p);
3219                         else
3220                                 diff_free_filepair(p);
3221                 }
3222         }
3223         free(q->queue);
3224         *q = outq;
3225 }
3226
3227 /* Check whether two filespecs with the same mode and size are identical */
3228 static int diff_filespec_is_identical(struct diff_filespec *one,
3229                                       struct diff_filespec *two)
3230 {
3231         if (S_ISGITLINK(one->mode))
3232                 return 0;
3233         if (diff_populate_filespec(one, 0))
3234                 return 0;
3235         if (diff_populate_filespec(two, 0))
3236                 return 0;
3237         return !memcmp(one->data, two->data, one->size);
3238 }
3239
3240 static void diffcore_skip_stat_unmatch(struct diff_options *diffopt)
3241 {
3242         int i;
3243         struct diff_queue_struct *q = &diff_queued_diff;
3244         struct diff_queue_struct outq;
3245         outq.queue = NULL;
3246         outq.nr = outq.alloc = 0;
3247
3248         for (i = 0; i < q->nr; i++) {
3249                 struct diff_filepair *p = q->queue[i];
3250
3251                 /*
3252                  * 1. Entries that come from stat info dirtyness
3253                  *    always have both sides (iow, not create/delete),
3254                  *    one side of the object name is unknown, with
3255                  *    the same mode and size.  Keep the ones that
3256                  *    do not match these criteria.  They have real
3257                  *    differences.
3258                  *
3259                  * 2. At this point, the file is known to be modified,
3260                  *    with the same mode and size, and the object
3261                  *    name of one side is unknown.  Need to inspect
3262                  *    the identical contents.
3263                  */
3264                 if (!DIFF_FILE_VALID(p->one) || /* (1) */
3265                     !DIFF_FILE_VALID(p->two) ||
3266                     (p->one->sha1_valid && p->two->sha1_valid) ||
3267                     (p->one->mode != p->two->mode) ||
3268                     diff_populate_filespec(p->one, 1) ||
3269                     diff_populate_filespec(p->two, 1) ||
3270                     (p->one->size != p->two->size) ||
3271                     !diff_filespec_is_identical(p->one, p->two)) /* (2) */
3272                         diff_q(&outq, p);
3273                 else {
3274                         /*
3275                          * The caller can subtract 1 from skip_stat_unmatch
3276                          * to determine how many paths were dirty only
3277                          * due to stat info mismatch.
3278                          */
3279                         if (!DIFF_OPT_TST(diffopt, NO_INDEX))
3280                                 diffopt->skip_stat_unmatch++;
3281                         diff_free_filepair(p);
3282                 }
3283         }
3284         free(q->queue);
3285         *q = outq;
3286 }
3287
3288 void diffcore_std(struct diff_options *options)
3289 {
3290         if (options->skip_stat_unmatch)
3291                 diffcore_skip_stat_unmatch(options);
3292         if (options->break_opt != -1)
3293                 diffcore_break(options->break_opt);
3294         if (options->detect_rename)
3295                 diffcore_rename(options);
3296         if (options->break_opt != -1)
3297                 diffcore_merge_broken();
3298         if (options->pickaxe)
3299                 diffcore_pickaxe(options->pickaxe, options->pickaxe_opts);
3300         if (options->orderfile)
3301                 diffcore_order(options->orderfile);
3302         diff_resolve_rename_copy();
3303         diffcore_apply_filter(options->filter);
3304
3305         if (diff_queued_diff.nr)
3306                 DIFF_OPT_SET(options, HAS_CHANGES);
3307         else
3308                 DIFF_OPT_CLR(options, HAS_CHANGES);
3309 }
3310
3311 int diff_result_code(struct diff_options *opt, int status)
3312 {
3313         int result = 0;
3314         if (!DIFF_OPT_TST(opt, EXIT_WITH_STATUS) &&
3315             !(opt->output_format & DIFF_FORMAT_CHECKDIFF))
3316                 return status;
3317         if (DIFF_OPT_TST(opt, EXIT_WITH_STATUS) &&
3318             DIFF_OPT_TST(opt, HAS_CHANGES))
3319                 result |= 01;
3320         if ((opt->output_format & DIFF_FORMAT_CHECKDIFF) &&
3321             DIFF_OPT_TST(opt, CHECK_FAILED))
3322                 result |= 02;
3323         return result;
3324 }
3325
3326 void diff_addremove(struct diff_options *options,
3327                     int addremove, unsigned mode,
3328                     const unsigned char *sha1,
3329                     const char *concatpath)
3330 {
3331         struct diff_filespec *one, *two;
3332
3333         if (DIFF_OPT_TST(options, IGNORE_SUBMODULES) && S_ISGITLINK(mode))
3334                 return;
3335
3336         /* This may look odd, but it is a preparation for
3337          * feeding "there are unchanged files which should
3338          * not produce diffs, but when you are doing copy
3339          * detection you would need them, so here they are"
3340          * entries to the diff-core.  They will be prefixed
3341          * with something like '=' or '*' (I haven't decided
3342          * which but should not make any difference).
3343          * Feeding the same new and old to diff_change()
3344          * also has the same effect.
3345          * Before the final output happens, they are pruned after
3346          * merged into rename/copy pairs as appropriate.
3347          */
3348         if (DIFF_OPT_TST(options, REVERSE_DIFF))
3349                 addremove = (addremove == '+' ? '-' :
3350                              addremove == '-' ? '+' : addremove);
3351
3352         if (options->prefix &&
3353             strncmp(concatpath, options->prefix, options->prefix_length))
3354                 return;
3355
3356         one = alloc_filespec(concatpath);
3357         two = alloc_filespec(concatpath);
3358
3359         if (addremove != '+')
3360                 fill_filespec(one, sha1, mode);
3361         if (addremove != '-')
3362                 fill_filespec(two, sha1, mode);
3363
3364         diff_queue(&diff_queued_diff, one, two);
3365         DIFF_OPT_SET(options, HAS_CHANGES);
3366 }
3367
3368 void diff_change(struct diff_options *options,
3369                  unsigned old_mode, unsigned new_mode,
3370                  const unsigned char *old_sha1,
3371                  const unsigned char *new_sha1,
3372                  const char *concatpath)
3373 {
3374         struct diff_filespec *one, *two;
3375
3376         if (DIFF_OPT_TST(options, IGNORE_SUBMODULES) && S_ISGITLINK(old_mode)
3377                         && S_ISGITLINK(new_mode))
3378                 return;
3379
3380         if (DIFF_OPT_TST(options, REVERSE_DIFF)) {
3381                 unsigned tmp;
3382                 const unsigned char *tmp_c;
3383                 tmp = old_mode; old_mode = new_mode; new_mode = tmp;
3384                 tmp_c = old_sha1; old_sha1 = new_sha1; new_sha1 = tmp_c;
3385         }
3386
3387         if (options->prefix &&
3388             strncmp(concatpath, options->prefix, options->prefix_length))
3389                 return;
3390
3391         one = alloc_filespec(concatpath);
3392         two = alloc_filespec(concatpath);
3393         fill_filespec(one, old_sha1, old_mode);
3394         fill_filespec(two, new_sha1, new_mode);
3395
3396         diff_queue(&diff_queued_diff, one, two);
3397         DIFF_OPT_SET(options, HAS_CHANGES);
3398 }
3399
3400 void diff_unmerge(struct diff_options *options,
3401                   const char *path,
3402                   unsigned mode, const unsigned char *sha1)
3403 {
3404         struct diff_filespec *one, *two;
3405
3406         if (options->prefix &&
3407             strncmp(path, options->prefix, options->prefix_length))
3408                 return;
3409
3410         one = alloc_filespec(path);
3411         two = alloc_filespec(path);
3412         fill_filespec(one, sha1, mode);
3413         diff_queue(&diff_queued_diff, one, two)->is_unmerged = 1;
3414 }
3415
3416 static char *run_textconv(const char *pgm, struct diff_filespec *spec,
3417                 size_t *outsize)
3418 {
3419         struct diff_tempfile temp;
3420         const char *argv[3];
3421         const char **arg = argv;
3422         struct child_process child;
3423         struct strbuf buf = STRBUF_INIT;
3424
3425         prepare_temp_file(spec->path, &temp, spec);
3426         *arg++ = pgm;
3427         *arg++ = temp.name;
3428         *arg = NULL;
3429
3430         memset(&child, 0, sizeof(child));
3431         child.argv = argv;
3432         child.out = -1;
3433         if (start_command(&child) != 0 ||
3434             strbuf_read(&buf, child.out, 0) < 0 ||
3435             finish_command(&child) != 0) {
3436                 if (temp.name == temp.tmp_path)
3437                         unlink(temp.name);
3438                 error("error running textconv command '%s'", pgm);
3439                 return NULL;
3440         }
3441         if (temp.name == temp.tmp_path)
3442                 unlink(temp.name);
3443
3444         return strbuf_detach(&buf, outsize);
3445 }