Merge branch 'maint'
[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 #include "sigchain.h"
16 #include "submodule.h"
17 #include "ll-merge.h"
18 #include "string-list.h"
19
20 #ifdef NO_FAST_WORKING_DIRECTORY
21 #define FAST_WORKING_DIRECTORY 0
22 #else
23 #define FAST_WORKING_DIRECTORY 1
24 #endif
25
26 static int diff_detect_rename_default;
27 static int diff_rename_limit_default = 400;
28 static int diff_suppress_blank_empty;
29 static int diff_use_color_default = -1;
30 static int diff_context_default = 3;
31 static const char *diff_word_regex_cfg;
32 static const char *external_diff_cmd_cfg;
33 int diff_auto_refresh_index = 1;
34 static int diff_mnemonic_prefix;
35 static int diff_no_prefix;
36 static int diff_stat_graph_width;
37 static int diff_dirstat_permille_default = 30;
38 static struct diff_options default_diff_options;
39 static long diff_algorithm;
40
41 static char diff_colors[][COLOR_MAXLEN] = {
42         GIT_COLOR_RESET,
43         GIT_COLOR_NORMAL,       /* PLAIN */
44         GIT_COLOR_BOLD,         /* METAINFO */
45         GIT_COLOR_CYAN,         /* FRAGINFO */
46         GIT_COLOR_RED,          /* OLD */
47         GIT_COLOR_GREEN,        /* NEW */
48         GIT_COLOR_YELLOW,       /* COMMIT */
49         GIT_COLOR_BG_RED,       /* WHITESPACE */
50         GIT_COLOR_NORMAL,       /* FUNCINFO */
51 };
52
53 static int parse_diff_color_slot(const char *var, int ofs)
54 {
55         if (!strcasecmp(var+ofs, "plain"))
56                 return DIFF_PLAIN;
57         if (!strcasecmp(var+ofs, "meta"))
58                 return DIFF_METAINFO;
59         if (!strcasecmp(var+ofs, "frag"))
60                 return DIFF_FRAGINFO;
61         if (!strcasecmp(var+ofs, "old"))
62                 return DIFF_FILE_OLD;
63         if (!strcasecmp(var+ofs, "new"))
64                 return DIFF_FILE_NEW;
65         if (!strcasecmp(var+ofs, "commit"))
66                 return DIFF_COMMIT;
67         if (!strcasecmp(var+ofs, "whitespace"))
68                 return DIFF_WHITESPACE;
69         if (!strcasecmp(var+ofs, "func"))
70                 return DIFF_FUNCINFO;
71         return -1;
72 }
73
74 static int parse_dirstat_params(struct diff_options *options, const char *params_string,
75                                 struct strbuf *errmsg)
76 {
77         char *params_copy = xstrdup(params_string);
78         struct string_list params = STRING_LIST_INIT_NODUP;
79         int ret = 0;
80         int i;
81
82         if (*params_copy)
83                 string_list_split_in_place(&params, params_copy, ',', -1);
84         for (i = 0; i < params.nr; i++) {
85                 const char *p = params.items[i].string;
86                 if (!strcmp(p, "changes")) {
87                         DIFF_OPT_CLR(options, DIRSTAT_BY_LINE);
88                         DIFF_OPT_CLR(options, DIRSTAT_BY_FILE);
89                 } else if (!strcmp(p, "lines")) {
90                         DIFF_OPT_SET(options, DIRSTAT_BY_LINE);
91                         DIFF_OPT_CLR(options, DIRSTAT_BY_FILE);
92                 } else if (!strcmp(p, "files")) {
93                         DIFF_OPT_CLR(options, DIRSTAT_BY_LINE);
94                         DIFF_OPT_SET(options, DIRSTAT_BY_FILE);
95                 } else if (!strcmp(p, "noncumulative")) {
96                         DIFF_OPT_CLR(options, DIRSTAT_CUMULATIVE);
97                 } else if (!strcmp(p, "cumulative")) {
98                         DIFF_OPT_SET(options, DIRSTAT_CUMULATIVE);
99                 } else if (isdigit(*p)) {
100                         char *end;
101                         int permille = strtoul(p, &end, 10) * 10;
102                         if (*end == '.' && isdigit(*++end)) {
103                                 /* only use first digit */
104                                 permille += *end - '0';
105                                 /* .. and ignore any further digits */
106                                 while (isdigit(*++end))
107                                         ; /* nothing */
108                         }
109                         if (!*end)
110                                 options->dirstat_permille = permille;
111                         else {
112                                 strbuf_addf(errmsg, _("  Failed to parse dirstat cut-off percentage '%s'\n"),
113                                             p);
114                                 ret++;
115                         }
116                 } else {
117                         strbuf_addf(errmsg, _("  Unknown dirstat parameter '%s'\n"), p);
118                         ret++;
119                 }
120
121         }
122         string_list_clear(&params, 0);
123         free(params_copy);
124         return ret;
125 }
126
127 static int parse_submodule_params(struct diff_options *options, const char *value)
128 {
129         if (!strcmp(value, "log"))
130                 DIFF_OPT_SET(options, SUBMODULE_LOG);
131         else if (!strcmp(value, "short"))
132                 DIFF_OPT_CLR(options, SUBMODULE_LOG);
133         else
134                 return -1;
135         return 0;
136 }
137
138 static int git_config_rename(const char *var, const char *value)
139 {
140         if (!value)
141                 return DIFF_DETECT_RENAME;
142         if (!strcasecmp(value, "copies") || !strcasecmp(value, "copy"))
143                 return  DIFF_DETECT_COPY;
144         return git_config_bool(var,value) ? DIFF_DETECT_RENAME : 0;
145 }
146
147 long parse_algorithm_value(const char *value)
148 {
149         if (!value)
150                 return -1;
151         else if (!strcasecmp(value, "myers") || !strcasecmp(value, "default"))
152                 return 0;
153         else if (!strcasecmp(value, "minimal"))
154                 return XDF_NEED_MINIMAL;
155         else if (!strcasecmp(value, "patience"))
156                 return XDF_PATIENCE_DIFF;
157         else if (!strcasecmp(value, "histogram"))
158                 return XDF_HISTOGRAM_DIFF;
159         return -1;
160 }
161
162 /*
163  * These are to give UI layer defaults.
164  * The core-level commands such as git-diff-files should
165  * never be affected by the setting of diff.renames
166  * the user happens to have in the configuration file.
167  */
168 int git_diff_ui_config(const char *var, const char *value, void *cb)
169 {
170         if (!strcmp(var, "diff.color") || !strcmp(var, "color.diff")) {
171                 diff_use_color_default = git_config_colorbool(var, value);
172                 return 0;
173         }
174         if (!strcmp(var, "diff.context")) {
175                 diff_context_default = git_config_int(var, value);
176                 if (diff_context_default < 0)
177                         return -1;
178                 return 0;
179         }
180         if (!strcmp(var, "diff.renames")) {
181                 diff_detect_rename_default = git_config_rename(var, value);
182                 return 0;
183         }
184         if (!strcmp(var, "diff.autorefreshindex")) {
185                 diff_auto_refresh_index = git_config_bool(var, value);
186                 return 0;
187         }
188         if (!strcmp(var, "diff.mnemonicprefix")) {
189                 diff_mnemonic_prefix = git_config_bool(var, value);
190                 return 0;
191         }
192         if (!strcmp(var, "diff.noprefix")) {
193                 diff_no_prefix = git_config_bool(var, value);
194                 return 0;
195         }
196         if (!strcmp(var, "diff.statgraphwidth")) {
197                 diff_stat_graph_width = git_config_int(var, value);
198                 return 0;
199         }
200         if (!strcmp(var, "diff.external"))
201                 return git_config_string(&external_diff_cmd_cfg, var, value);
202         if (!strcmp(var, "diff.wordregex"))
203                 return git_config_string(&diff_word_regex_cfg, var, value);
204
205         if (!strcmp(var, "diff.ignoresubmodules"))
206                 handle_ignore_submodules_arg(&default_diff_options, value);
207
208         if (!strcmp(var, "diff.submodule")) {
209                 if (parse_submodule_params(&default_diff_options, value))
210                         warning(_("Unknown value for 'diff.submodule' config variable: '%s'"),
211                                 value);
212                 return 0;
213         }
214
215         if (!strcmp(var, "diff.algorithm")) {
216                 diff_algorithm = parse_algorithm_value(value);
217                 if (diff_algorithm < 0)
218                         return -1;
219                 return 0;
220         }
221
222         if (git_color_config(var, value, cb) < 0)
223                 return -1;
224
225         return git_diff_basic_config(var, value, cb);
226 }
227
228 int git_diff_basic_config(const char *var, const char *value, void *cb)
229 {
230         if (!strcmp(var, "diff.renamelimit")) {
231                 diff_rename_limit_default = git_config_int(var, value);
232                 return 0;
233         }
234
235         if (userdiff_config(var, value) < 0)
236                 return -1;
237
238         if (!prefixcmp(var, "diff.color.") || !prefixcmp(var, "color.diff.")) {
239                 int slot = parse_diff_color_slot(var, 11);
240                 if (slot < 0)
241                         return 0;
242                 if (!value)
243                         return config_error_nonbool(var);
244                 color_parse(value, var, diff_colors[slot]);
245                 return 0;
246         }
247
248         /* like GNU diff's --suppress-blank-empty option  */
249         if (!strcmp(var, "diff.suppressblankempty") ||
250                         /* for backwards compatibility */
251                         !strcmp(var, "diff.suppress-blank-empty")) {
252                 diff_suppress_blank_empty = git_config_bool(var, value);
253                 return 0;
254         }
255
256         if (!strcmp(var, "diff.dirstat")) {
257                 struct strbuf errmsg = STRBUF_INIT;
258                 default_diff_options.dirstat_permille = diff_dirstat_permille_default;
259                 if (parse_dirstat_params(&default_diff_options, value, &errmsg))
260                         warning(_("Found errors in 'diff.dirstat' config variable:\n%s"),
261                                 errmsg.buf);
262                 strbuf_release(&errmsg);
263                 diff_dirstat_permille_default = default_diff_options.dirstat_permille;
264                 return 0;
265         }
266
267         if (!prefixcmp(var, "submodule."))
268                 return parse_submodule_config_option(var, value);
269
270         return git_default_config(var, value, cb);
271 }
272
273 static char *quote_two(const char *one, const char *two)
274 {
275         int need_one = quote_c_style(one, NULL, NULL, 1);
276         int need_two = quote_c_style(two, NULL, NULL, 1);
277         struct strbuf res = STRBUF_INIT;
278
279         if (need_one + need_two) {
280                 strbuf_addch(&res, '"');
281                 quote_c_style(one, &res, NULL, 1);
282                 quote_c_style(two, &res, NULL, 1);
283                 strbuf_addch(&res, '"');
284         } else {
285                 strbuf_addstr(&res, one);
286                 strbuf_addstr(&res, two);
287         }
288         return strbuf_detach(&res, NULL);
289 }
290
291 static const char *external_diff(void)
292 {
293         static const char *external_diff_cmd = NULL;
294         static int done_preparing = 0;
295
296         if (done_preparing)
297                 return external_diff_cmd;
298         external_diff_cmd = getenv("GIT_EXTERNAL_DIFF");
299         if (!external_diff_cmd)
300                 external_diff_cmd = external_diff_cmd_cfg;
301         done_preparing = 1;
302         return external_diff_cmd;
303 }
304
305 static struct diff_tempfile {
306         const char *name; /* filename external diff should read from */
307         char hex[41];
308         char mode[10];
309         char tmp_path[PATH_MAX];
310 } diff_temp[2];
311
312 typedef unsigned long (*sane_truncate_fn)(char *line, unsigned long len);
313
314 struct emit_callback {
315         int color_diff;
316         unsigned ws_rule;
317         int blank_at_eof_in_preimage;
318         int blank_at_eof_in_postimage;
319         int lno_in_preimage;
320         int lno_in_postimage;
321         sane_truncate_fn truncate;
322         const char **label_path;
323         struct diff_words_data *diff_words;
324         struct diff_options *opt;
325         int *found_changesp;
326         struct strbuf *header;
327 };
328
329 static int count_lines(const char *data, int size)
330 {
331         int count, ch, completely_empty = 1, nl_just_seen = 0;
332         count = 0;
333         while (0 < size--) {
334                 ch = *data++;
335                 if (ch == '\n') {
336                         count++;
337                         nl_just_seen = 1;
338                         completely_empty = 0;
339                 }
340                 else {
341                         nl_just_seen = 0;
342                         completely_empty = 0;
343                 }
344         }
345         if (completely_empty)
346                 return 0;
347         if (!nl_just_seen)
348                 count++; /* no trailing newline */
349         return count;
350 }
351
352 static int fill_mmfile(mmfile_t *mf, struct diff_filespec *one)
353 {
354         if (!DIFF_FILE_VALID(one)) {
355                 mf->ptr = (char *)""; /* does not matter */
356                 mf->size = 0;
357                 return 0;
358         }
359         else if (diff_populate_filespec(one, 0))
360                 return -1;
361
362         mf->ptr = one->data;
363         mf->size = one->size;
364         return 0;
365 }
366
367 /* like fill_mmfile, but only for size, so we can avoid retrieving blob */
368 static unsigned long diff_filespec_size(struct diff_filespec *one)
369 {
370         if (!DIFF_FILE_VALID(one))
371                 return 0;
372         diff_populate_filespec(one, 1);
373         return one->size;
374 }
375
376 static int count_trailing_blank(mmfile_t *mf, unsigned ws_rule)
377 {
378         char *ptr = mf->ptr;
379         long size = mf->size;
380         int cnt = 0;
381
382         if (!size)
383                 return cnt;
384         ptr += size - 1; /* pointing at the very end */
385         if (*ptr != '\n')
386                 ; /* incomplete line */
387         else
388                 ptr--; /* skip the last LF */
389         while (mf->ptr < ptr) {
390                 char *prev_eol;
391                 for (prev_eol = ptr; mf->ptr <= prev_eol; prev_eol--)
392                         if (*prev_eol == '\n')
393                                 break;
394                 if (!ws_blank_line(prev_eol + 1, ptr - prev_eol, ws_rule))
395                         break;
396                 cnt++;
397                 ptr = prev_eol - 1;
398         }
399         return cnt;
400 }
401
402 static void check_blank_at_eof(mmfile_t *mf1, mmfile_t *mf2,
403                                struct emit_callback *ecbdata)
404 {
405         int l1, l2, at;
406         unsigned ws_rule = ecbdata->ws_rule;
407         l1 = count_trailing_blank(mf1, ws_rule);
408         l2 = count_trailing_blank(mf2, ws_rule);
409         if (l2 <= l1) {
410                 ecbdata->blank_at_eof_in_preimage = 0;
411                 ecbdata->blank_at_eof_in_postimage = 0;
412                 return;
413         }
414         at = count_lines(mf1->ptr, mf1->size);
415         ecbdata->blank_at_eof_in_preimage = (at - l1) + 1;
416
417         at = count_lines(mf2->ptr, mf2->size);
418         ecbdata->blank_at_eof_in_postimage = (at - l2) + 1;
419 }
420
421 static void emit_line_0(struct diff_options *o, const char *set, const char *reset,
422                         int first, const char *line, int len)
423 {
424         int has_trailing_newline, has_trailing_carriage_return;
425         int nofirst;
426         FILE *file = o->file;
427
428         fputs(diff_line_prefix(o), file);
429
430         if (len == 0) {
431                 has_trailing_newline = (first == '\n');
432                 has_trailing_carriage_return = (!has_trailing_newline &&
433                                                 (first == '\r'));
434                 nofirst = has_trailing_newline || has_trailing_carriage_return;
435         } else {
436                 has_trailing_newline = (len > 0 && line[len-1] == '\n');
437                 if (has_trailing_newline)
438                         len--;
439                 has_trailing_carriage_return = (len > 0 && line[len-1] == '\r');
440                 if (has_trailing_carriage_return)
441                         len--;
442                 nofirst = 0;
443         }
444
445         if (len || !nofirst) {
446                 fputs(set, file);
447                 if (!nofirst)
448                         fputc(first, file);
449                 fwrite(line, len, 1, file);
450                 fputs(reset, file);
451         }
452         if (has_trailing_carriage_return)
453                 fputc('\r', file);
454         if (has_trailing_newline)
455                 fputc('\n', file);
456 }
457
458 static void emit_line(struct diff_options *o, const char *set, const char *reset,
459                       const char *line, int len)
460 {
461         emit_line_0(o, set, reset, line[0], line+1, len-1);
462 }
463
464 static int new_blank_line_at_eof(struct emit_callback *ecbdata, const char *line, int len)
465 {
466         if (!((ecbdata->ws_rule & WS_BLANK_AT_EOF) &&
467               ecbdata->blank_at_eof_in_preimage &&
468               ecbdata->blank_at_eof_in_postimage &&
469               ecbdata->blank_at_eof_in_preimage <= ecbdata->lno_in_preimage &&
470               ecbdata->blank_at_eof_in_postimage <= ecbdata->lno_in_postimage))
471                 return 0;
472         return ws_blank_line(line, len, ecbdata->ws_rule);
473 }
474
475 static void emit_add_line(const char *reset,
476                           struct emit_callback *ecbdata,
477                           const char *line, int len)
478 {
479         const char *ws = diff_get_color(ecbdata->color_diff, DIFF_WHITESPACE);
480         const char *set = diff_get_color(ecbdata->color_diff, DIFF_FILE_NEW);
481
482         if (!*ws)
483                 emit_line_0(ecbdata->opt, set, reset, '+', line, len);
484         else if (new_blank_line_at_eof(ecbdata, line, len))
485                 /* Blank line at EOF - paint '+' as well */
486                 emit_line_0(ecbdata->opt, ws, reset, '+', line, len);
487         else {
488                 /* Emit just the prefix, then the rest. */
489                 emit_line_0(ecbdata->opt, set, reset, '+', "", 0);
490                 ws_check_emit(line, len, ecbdata->ws_rule,
491                               ecbdata->opt->file, set, reset, ws);
492         }
493 }
494
495 static void emit_hunk_header(struct emit_callback *ecbdata,
496                              const char *line, int len)
497 {
498         const char *plain = diff_get_color(ecbdata->color_diff, DIFF_PLAIN);
499         const char *frag = diff_get_color(ecbdata->color_diff, DIFF_FRAGINFO);
500         const char *func = diff_get_color(ecbdata->color_diff, DIFF_FUNCINFO);
501         const char *reset = diff_get_color(ecbdata->color_diff, DIFF_RESET);
502         static const char atat[2] = { '@', '@' };
503         const char *cp, *ep;
504         struct strbuf msgbuf = STRBUF_INIT;
505         int org_len = len;
506         int i = 1;
507
508         /*
509          * As a hunk header must begin with "@@ -<old>, +<new> @@",
510          * it always is at least 10 bytes long.
511          */
512         if (len < 10 ||
513             memcmp(line, atat, 2) ||
514             !(ep = memmem(line + 2, len - 2, atat, 2))) {
515                 emit_line(ecbdata->opt, plain, reset, line, len);
516                 return;
517         }
518         ep += 2; /* skip over @@ */
519
520         /* The hunk header in fraginfo color */
521         strbuf_add(&msgbuf, frag, strlen(frag));
522         strbuf_add(&msgbuf, line, ep - line);
523         strbuf_add(&msgbuf, reset, strlen(reset));
524
525         /*
526          * trailing "\r\n"
527          */
528         for ( ; i < 3; i++)
529                 if (line[len - i] == '\r' || line[len - i] == '\n')
530                         len--;
531
532         /* blank before the func header */
533         for (cp = ep; ep - line < len; ep++)
534                 if (*ep != ' ' && *ep != '\t')
535                         break;
536         if (ep != cp) {
537                 strbuf_add(&msgbuf, plain, strlen(plain));
538                 strbuf_add(&msgbuf, cp, ep - cp);
539                 strbuf_add(&msgbuf, reset, strlen(reset));
540         }
541
542         if (ep < line + len) {
543                 strbuf_add(&msgbuf, func, strlen(func));
544                 strbuf_add(&msgbuf, ep, line + len - ep);
545                 strbuf_add(&msgbuf, reset, strlen(reset));
546         }
547
548         strbuf_add(&msgbuf, line + len, org_len - len);
549         emit_line(ecbdata->opt, "", "", msgbuf.buf, msgbuf.len);
550         strbuf_release(&msgbuf);
551 }
552
553 static struct diff_tempfile *claim_diff_tempfile(void) {
554         int i;
555         for (i = 0; i < ARRAY_SIZE(diff_temp); i++)
556                 if (!diff_temp[i].name)
557                         return diff_temp + i;
558         die("BUG: diff is failing to clean up its tempfiles");
559 }
560
561 static int remove_tempfile_installed;
562
563 static void remove_tempfile(void)
564 {
565         int i;
566         for (i = 0; i < ARRAY_SIZE(diff_temp); i++) {
567                 if (diff_temp[i].name == diff_temp[i].tmp_path)
568                         unlink_or_warn(diff_temp[i].name);
569                 diff_temp[i].name = NULL;
570         }
571 }
572
573 static void remove_tempfile_on_signal(int signo)
574 {
575         remove_tempfile();
576         sigchain_pop(signo);
577         raise(signo);
578 }
579
580 static void print_line_count(FILE *file, int count)
581 {
582         switch (count) {
583         case 0:
584                 fprintf(file, "0,0");
585                 break;
586         case 1:
587                 fprintf(file, "1");
588                 break;
589         default:
590                 fprintf(file, "1,%d", count);
591                 break;
592         }
593 }
594
595 static void emit_rewrite_lines(struct emit_callback *ecb,
596                                int prefix, const char *data, int size)
597 {
598         const char *endp = NULL;
599         static const char *nneof = " No newline at end of file\n";
600         const char *old = diff_get_color(ecb->color_diff, DIFF_FILE_OLD);
601         const char *reset = diff_get_color(ecb->color_diff, DIFF_RESET);
602
603         while (0 < size) {
604                 int len;
605
606                 endp = memchr(data, '\n', size);
607                 len = endp ? (endp - data + 1) : size;
608                 if (prefix != '+') {
609                         ecb->lno_in_preimage++;
610                         emit_line_0(ecb->opt, old, reset, '-',
611                                     data, len);
612                 } else {
613                         ecb->lno_in_postimage++;
614                         emit_add_line(reset, ecb, data, len);
615                 }
616                 size -= len;
617                 data += len;
618         }
619         if (!endp) {
620                 const char *plain = diff_get_color(ecb->color_diff,
621                                                    DIFF_PLAIN);
622                 putc('\n', ecb->opt->file);
623                 emit_line_0(ecb->opt, plain, reset, '\\',
624                             nneof, strlen(nneof));
625         }
626 }
627
628 static void emit_rewrite_diff(const char *name_a,
629                               const char *name_b,
630                               struct diff_filespec *one,
631                               struct diff_filespec *two,
632                               struct userdiff_driver *textconv_one,
633                               struct userdiff_driver *textconv_two,
634                               struct diff_options *o)
635 {
636         int lc_a, lc_b;
637         const char *name_a_tab, *name_b_tab;
638         const char *metainfo = diff_get_color(o->use_color, DIFF_METAINFO);
639         const char *fraginfo = diff_get_color(o->use_color, DIFF_FRAGINFO);
640         const char *reset = diff_get_color(o->use_color, DIFF_RESET);
641         static struct strbuf a_name = STRBUF_INIT, b_name = STRBUF_INIT;
642         const char *a_prefix, *b_prefix;
643         char *data_one, *data_two;
644         size_t size_one, size_two;
645         struct emit_callback ecbdata;
646         const char *line_prefix = diff_line_prefix(o);
647
648         if (diff_mnemonic_prefix && DIFF_OPT_TST(o, REVERSE_DIFF)) {
649                 a_prefix = o->b_prefix;
650                 b_prefix = o->a_prefix;
651         } else {
652                 a_prefix = o->a_prefix;
653                 b_prefix = o->b_prefix;
654         }
655
656         name_a += (*name_a == '/');
657         name_b += (*name_b == '/');
658         name_a_tab = strchr(name_a, ' ') ? "\t" : "";
659         name_b_tab = strchr(name_b, ' ') ? "\t" : "";
660
661         strbuf_reset(&a_name);
662         strbuf_reset(&b_name);
663         quote_two_c_style(&a_name, a_prefix, name_a, 0);
664         quote_two_c_style(&b_name, b_prefix, name_b, 0);
665
666         size_one = fill_textconv(textconv_one, one, &data_one);
667         size_two = fill_textconv(textconv_two, two, &data_two);
668
669         memset(&ecbdata, 0, sizeof(ecbdata));
670         ecbdata.color_diff = want_color(o->use_color);
671         ecbdata.found_changesp = &o->found_changes;
672         ecbdata.ws_rule = whitespace_rule(name_b ? name_b : name_a);
673         ecbdata.opt = o;
674         if (ecbdata.ws_rule & WS_BLANK_AT_EOF) {
675                 mmfile_t mf1, mf2;
676                 mf1.ptr = (char *)data_one;
677                 mf2.ptr = (char *)data_two;
678                 mf1.size = size_one;
679                 mf2.size = size_two;
680                 check_blank_at_eof(&mf1, &mf2, &ecbdata);
681         }
682         ecbdata.lno_in_preimage = 1;
683         ecbdata.lno_in_postimage = 1;
684
685         lc_a = count_lines(data_one, size_one);
686         lc_b = count_lines(data_two, size_two);
687         fprintf(o->file,
688                 "%s%s--- %s%s%s\n%s%s+++ %s%s%s\n%s%s@@ -",
689                 line_prefix, metainfo, a_name.buf, name_a_tab, reset,
690                 line_prefix, metainfo, b_name.buf, name_b_tab, reset,
691                 line_prefix, fraginfo);
692         if (!o->irreversible_delete)
693                 print_line_count(o->file, lc_a);
694         else
695                 fprintf(o->file, "?,?");
696         fprintf(o->file, " +");
697         print_line_count(o->file, lc_b);
698         fprintf(o->file, " @@%s\n", reset);
699         if (lc_a && !o->irreversible_delete)
700                 emit_rewrite_lines(&ecbdata, '-', data_one, size_one);
701         if (lc_b)
702                 emit_rewrite_lines(&ecbdata, '+', data_two, size_two);
703         if (textconv_one)
704                 free((char *)data_one);
705         if (textconv_two)
706                 free((char *)data_two);
707 }
708
709 struct diff_words_buffer {
710         mmfile_t text;
711         long alloc;
712         struct diff_words_orig {
713                 const char *begin, *end;
714         } *orig;
715         int orig_nr, orig_alloc;
716 };
717
718 static void diff_words_append(char *line, unsigned long len,
719                 struct diff_words_buffer *buffer)
720 {
721         ALLOC_GROW(buffer->text.ptr, buffer->text.size + len, buffer->alloc);
722         line++;
723         len--;
724         memcpy(buffer->text.ptr + buffer->text.size, line, len);
725         buffer->text.size += len;
726         buffer->text.ptr[buffer->text.size] = '\0';
727 }
728
729 struct diff_words_style_elem {
730         const char *prefix;
731         const char *suffix;
732         const char *color; /* NULL; filled in by the setup code if
733                             * color is enabled */
734 };
735
736 struct diff_words_style {
737         enum diff_words_type type;
738         struct diff_words_style_elem new, old, ctx;
739         const char *newline;
740 };
741
742 static struct diff_words_style diff_words_styles[] = {
743         { DIFF_WORDS_PORCELAIN, {"+", "\n"}, {"-", "\n"}, {" ", "\n"}, "~\n" },
744         { DIFF_WORDS_PLAIN, {"{+", "+}"}, {"[-", "-]"}, {"", ""}, "\n" },
745         { DIFF_WORDS_COLOR, {"", ""}, {"", ""}, {"", ""}, "\n" }
746 };
747
748 struct diff_words_data {
749         struct diff_words_buffer minus, plus;
750         const char *current_plus;
751         int last_minus;
752         struct diff_options *opt;
753         regex_t *word_regex;
754         enum diff_words_type type;
755         struct diff_words_style *style;
756 };
757
758 static int fn_out_diff_words_write_helper(FILE *fp,
759                                           struct diff_words_style_elem *st_el,
760                                           const char *newline,
761                                           size_t count, const char *buf,
762                                           const char *line_prefix)
763 {
764         int print = 0;
765
766         while (count) {
767                 char *p = memchr(buf, '\n', count);
768                 if (print)
769                         fputs(line_prefix, fp);
770                 if (p != buf) {
771                         if (st_el->color && fputs(st_el->color, fp) < 0)
772                                 return -1;
773                         if (fputs(st_el->prefix, fp) < 0 ||
774                             fwrite(buf, p ? p - buf : count, 1, fp) != 1 ||
775                             fputs(st_el->suffix, fp) < 0)
776                                 return -1;
777                         if (st_el->color && *st_el->color
778                             && fputs(GIT_COLOR_RESET, fp) < 0)
779                                 return -1;
780                 }
781                 if (!p)
782                         return 0;
783                 if (fputs(newline, fp) < 0)
784                         return -1;
785                 count -= p + 1 - buf;
786                 buf = p + 1;
787                 print = 1;
788         }
789         return 0;
790 }
791
792 /*
793  * '--color-words' algorithm can be described as:
794  *
795  *   1. collect a the minus/plus lines of a diff hunk, divided into
796  *      minus-lines and plus-lines;
797  *
798  *   2. break both minus-lines and plus-lines into words and
799  *      place them into two mmfile_t with one word for each line;
800  *
801  *   3. use xdiff to run diff on the two mmfile_t to get the words level diff;
802  *
803  * And for the common parts of the both file, we output the plus side text.
804  * diff_words->current_plus is used to trace the current position of the plus file
805  * which printed. diff_words->last_minus is used to trace the last minus word
806  * printed.
807  *
808  * For '--graph' to work with '--color-words', we need to output the graph prefix
809  * on each line of color words output. Generally, there are two conditions on
810  * which we should output the prefix.
811  *
812  *   1. diff_words->last_minus == 0 &&
813  *      diff_words->current_plus == diff_words->plus.text.ptr
814  *
815  *      that is: the plus text must start as a new line, and if there is no minus
816  *      word printed, a graph prefix must be printed.
817  *
818  *   2. diff_words->current_plus > diff_words->plus.text.ptr &&
819  *      *(diff_words->current_plus - 1) == '\n'
820  *
821  *      that is: a graph prefix must be printed following a '\n'
822  */
823 static int color_words_output_graph_prefix(struct diff_words_data *diff_words)
824 {
825         if ((diff_words->last_minus == 0 &&
826                 diff_words->current_plus == diff_words->plus.text.ptr) ||
827                 (diff_words->current_plus > diff_words->plus.text.ptr &&
828                 *(diff_words->current_plus - 1) == '\n')) {
829                 return 1;
830         } else {
831                 return 0;
832         }
833 }
834
835 static void fn_out_diff_words_aux(void *priv, char *line, unsigned long len)
836 {
837         struct diff_words_data *diff_words = priv;
838         struct diff_words_style *style = diff_words->style;
839         int minus_first, minus_len, plus_first, plus_len;
840         const char *minus_begin, *minus_end, *plus_begin, *plus_end;
841         struct diff_options *opt = diff_words->opt;
842         const char *line_prefix;
843
844         if (line[0] != '@' || parse_hunk_header(line, len,
845                         &minus_first, &minus_len, &plus_first, &plus_len))
846                 return;
847
848         assert(opt);
849         line_prefix = diff_line_prefix(opt);
850
851         /* POSIX requires that first be decremented by one if len == 0... */
852         if (minus_len) {
853                 minus_begin = diff_words->minus.orig[minus_first].begin;
854                 minus_end =
855                         diff_words->minus.orig[minus_first + minus_len - 1].end;
856         } else
857                 minus_begin = minus_end =
858                         diff_words->minus.orig[minus_first].end;
859
860         if (plus_len) {
861                 plus_begin = diff_words->plus.orig[plus_first].begin;
862                 plus_end = diff_words->plus.orig[plus_first + plus_len - 1].end;
863         } else
864                 plus_begin = plus_end = diff_words->plus.orig[plus_first].end;
865
866         if (color_words_output_graph_prefix(diff_words)) {
867                 fputs(line_prefix, diff_words->opt->file);
868         }
869         if (diff_words->current_plus != plus_begin) {
870                 fn_out_diff_words_write_helper(diff_words->opt->file,
871                                 &style->ctx, style->newline,
872                                 plus_begin - diff_words->current_plus,
873                                 diff_words->current_plus, line_prefix);
874                 if (*(plus_begin - 1) == '\n')
875                         fputs(line_prefix, diff_words->opt->file);
876         }
877         if (minus_begin != minus_end) {
878                 fn_out_diff_words_write_helper(diff_words->opt->file,
879                                 &style->old, style->newline,
880                                 minus_end - minus_begin, minus_begin,
881                                 line_prefix);
882         }
883         if (plus_begin != plus_end) {
884                 fn_out_diff_words_write_helper(diff_words->opt->file,
885                                 &style->new, style->newline,
886                                 plus_end - plus_begin, plus_begin,
887                                 line_prefix);
888         }
889
890         diff_words->current_plus = plus_end;
891         diff_words->last_minus = minus_first;
892 }
893
894 /* This function starts looking at *begin, and returns 0 iff a word was found. */
895 static int find_word_boundaries(mmfile_t *buffer, regex_t *word_regex,
896                 int *begin, int *end)
897 {
898         if (word_regex && *begin < buffer->size) {
899                 regmatch_t match[1];
900                 if (!regexec(word_regex, buffer->ptr + *begin, 1, match, 0)) {
901                         char *p = memchr(buffer->ptr + *begin + match[0].rm_so,
902                                         '\n', match[0].rm_eo - match[0].rm_so);
903                         *end = p ? p - buffer->ptr : match[0].rm_eo + *begin;
904                         *begin += match[0].rm_so;
905                         return *begin >= *end;
906                 }
907                 return -1;
908         }
909
910         /* find the next word */
911         while (*begin < buffer->size && isspace(buffer->ptr[*begin]))
912                 (*begin)++;
913         if (*begin >= buffer->size)
914                 return -1;
915
916         /* find the end of the word */
917         *end = *begin + 1;
918         while (*end < buffer->size && !isspace(buffer->ptr[*end]))
919                 (*end)++;
920
921         return 0;
922 }
923
924 /*
925  * This function splits the words in buffer->text, stores the list with
926  * newline separator into out, and saves the offsets of the original words
927  * in buffer->orig.
928  */
929 static void diff_words_fill(struct diff_words_buffer *buffer, mmfile_t *out,
930                 regex_t *word_regex)
931 {
932         int i, j;
933         long alloc = 0;
934
935         out->size = 0;
936         out->ptr = NULL;
937
938         /* fake an empty "0th" word */
939         ALLOC_GROW(buffer->orig, 1, buffer->orig_alloc);
940         buffer->orig[0].begin = buffer->orig[0].end = buffer->text.ptr;
941         buffer->orig_nr = 1;
942
943         for (i = 0; i < buffer->text.size; i++) {
944                 if (find_word_boundaries(&buffer->text, word_regex, &i, &j))
945                         return;
946
947                 /* store original boundaries */
948                 ALLOC_GROW(buffer->orig, buffer->orig_nr + 1,
949                                 buffer->orig_alloc);
950                 buffer->orig[buffer->orig_nr].begin = buffer->text.ptr + i;
951                 buffer->orig[buffer->orig_nr].end = buffer->text.ptr + j;
952                 buffer->orig_nr++;
953
954                 /* store one word */
955                 ALLOC_GROW(out->ptr, out->size + j - i + 1, alloc);
956                 memcpy(out->ptr + out->size, buffer->text.ptr + i, j - i);
957                 out->ptr[out->size + j - i] = '\n';
958                 out->size += j - i + 1;
959
960                 i = j - 1;
961         }
962 }
963
964 /* this executes the word diff on the accumulated buffers */
965 static void diff_words_show(struct diff_words_data *diff_words)
966 {
967         xpparam_t xpp;
968         xdemitconf_t xecfg;
969         mmfile_t minus, plus;
970         struct diff_words_style *style = diff_words->style;
971
972         struct diff_options *opt = diff_words->opt;
973         const char *line_prefix;
974
975         assert(opt);
976         line_prefix = diff_line_prefix(opt);
977
978         /* special case: only removal */
979         if (!diff_words->plus.text.size) {
980                 fputs(line_prefix, diff_words->opt->file);
981                 fn_out_diff_words_write_helper(diff_words->opt->file,
982                         &style->old, style->newline,
983                         diff_words->minus.text.size,
984                         diff_words->minus.text.ptr, line_prefix);
985                 diff_words->minus.text.size = 0;
986                 return;
987         }
988
989         diff_words->current_plus = diff_words->plus.text.ptr;
990         diff_words->last_minus = 0;
991
992         memset(&xpp, 0, sizeof(xpp));
993         memset(&xecfg, 0, sizeof(xecfg));
994         diff_words_fill(&diff_words->minus, &minus, diff_words->word_regex);
995         diff_words_fill(&diff_words->plus, &plus, diff_words->word_regex);
996         xpp.flags = 0;
997         /* as only the hunk header will be parsed, we need a 0-context */
998         xecfg.ctxlen = 0;
999         xdi_diff_outf(&minus, &plus, fn_out_diff_words_aux, diff_words,
1000                       &xpp, &xecfg);
1001         free(minus.ptr);
1002         free(plus.ptr);
1003         if (diff_words->current_plus != diff_words->plus.text.ptr +
1004                         diff_words->plus.text.size) {
1005                 if (color_words_output_graph_prefix(diff_words))
1006                         fputs(line_prefix, diff_words->opt->file);
1007                 fn_out_diff_words_write_helper(diff_words->opt->file,
1008                         &style->ctx, style->newline,
1009                         diff_words->plus.text.ptr + diff_words->plus.text.size
1010                         - diff_words->current_plus, diff_words->current_plus,
1011                         line_prefix);
1012         }
1013         diff_words->minus.text.size = diff_words->plus.text.size = 0;
1014 }
1015
1016 /* In "color-words" mode, show word-diff of words accumulated in the buffer */
1017 static void diff_words_flush(struct emit_callback *ecbdata)
1018 {
1019         if (ecbdata->diff_words->minus.text.size ||
1020             ecbdata->diff_words->plus.text.size)
1021                 diff_words_show(ecbdata->diff_words);
1022 }
1023
1024 static void diff_filespec_load_driver(struct diff_filespec *one)
1025 {
1026         /* Use already-loaded driver */
1027         if (one->driver)
1028                 return;
1029
1030         if (S_ISREG(one->mode))
1031                 one->driver = userdiff_find_by_path(one->path);
1032
1033         /* Fallback to default settings */
1034         if (!one->driver)
1035                 one->driver = userdiff_find_by_name("default");
1036 }
1037
1038 static const char *userdiff_word_regex(struct diff_filespec *one)
1039 {
1040         diff_filespec_load_driver(one);
1041         return one->driver->word_regex;
1042 }
1043
1044 static void init_diff_words_data(struct emit_callback *ecbdata,
1045                                  struct diff_options *orig_opts,
1046                                  struct diff_filespec *one,
1047                                  struct diff_filespec *two)
1048 {
1049         int i;
1050         struct diff_options *o = xmalloc(sizeof(struct diff_options));
1051         memcpy(o, orig_opts, sizeof(struct diff_options));
1052
1053         ecbdata->diff_words =
1054                 xcalloc(1, sizeof(struct diff_words_data));
1055         ecbdata->diff_words->type = o->word_diff;
1056         ecbdata->diff_words->opt = o;
1057         if (!o->word_regex)
1058                 o->word_regex = userdiff_word_regex(one);
1059         if (!o->word_regex)
1060                 o->word_regex = userdiff_word_regex(two);
1061         if (!o->word_regex)
1062                 o->word_regex = diff_word_regex_cfg;
1063         if (o->word_regex) {
1064                 ecbdata->diff_words->word_regex = (regex_t *)
1065                         xmalloc(sizeof(regex_t));
1066                 if (regcomp(ecbdata->diff_words->word_regex,
1067                             o->word_regex,
1068                             REG_EXTENDED | REG_NEWLINE))
1069                         die ("Invalid regular expression: %s",
1070                              o->word_regex);
1071         }
1072         for (i = 0; i < ARRAY_SIZE(diff_words_styles); i++) {
1073                 if (o->word_diff == diff_words_styles[i].type) {
1074                         ecbdata->diff_words->style =
1075                                 &diff_words_styles[i];
1076                         break;
1077                 }
1078         }
1079         if (want_color(o->use_color)) {
1080                 struct diff_words_style *st = ecbdata->diff_words->style;
1081                 st->old.color = diff_get_color_opt(o, DIFF_FILE_OLD);
1082                 st->new.color = diff_get_color_opt(o, DIFF_FILE_NEW);
1083                 st->ctx.color = diff_get_color_opt(o, DIFF_PLAIN);
1084         }
1085 }
1086
1087 static void free_diff_words_data(struct emit_callback *ecbdata)
1088 {
1089         if (ecbdata->diff_words) {
1090                 diff_words_flush(ecbdata);
1091                 free (ecbdata->diff_words->opt);
1092                 free (ecbdata->diff_words->minus.text.ptr);
1093                 free (ecbdata->diff_words->minus.orig);
1094                 free (ecbdata->diff_words->plus.text.ptr);
1095                 free (ecbdata->diff_words->plus.orig);
1096                 if (ecbdata->diff_words->word_regex) {
1097                         regfree(ecbdata->diff_words->word_regex);
1098                         free(ecbdata->diff_words->word_regex);
1099                 }
1100                 free(ecbdata->diff_words);
1101                 ecbdata->diff_words = NULL;
1102         }
1103 }
1104
1105 const char *diff_get_color(int diff_use_color, enum color_diff ix)
1106 {
1107         if (want_color(diff_use_color))
1108                 return diff_colors[ix];
1109         return "";
1110 }
1111
1112 const char *diff_line_prefix(struct diff_options *opt)
1113 {
1114         struct strbuf *msgbuf;
1115         if (!opt->output_prefix)
1116                 return "";
1117
1118         msgbuf = opt->output_prefix(opt, opt->output_prefix_data);
1119         return msgbuf->buf;
1120 }
1121
1122 static unsigned long sane_truncate_line(struct emit_callback *ecb, char *line, unsigned long len)
1123 {
1124         const char *cp;
1125         unsigned long allot;
1126         size_t l = len;
1127
1128         if (ecb->truncate)
1129                 return ecb->truncate(line, len);
1130         cp = line;
1131         allot = l;
1132         while (0 < l) {
1133                 (void) utf8_width(&cp, &l);
1134                 if (!cp)
1135                         break; /* truncated in the middle? */
1136         }
1137         return allot - l;
1138 }
1139
1140 static void find_lno(const char *line, struct emit_callback *ecbdata)
1141 {
1142         const char *p;
1143         ecbdata->lno_in_preimage = 0;
1144         ecbdata->lno_in_postimage = 0;
1145         p = strchr(line, '-');
1146         if (!p)
1147                 return; /* cannot happen */
1148         ecbdata->lno_in_preimage = strtol(p + 1, NULL, 10);
1149         p = strchr(p, '+');
1150         if (!p)
1151                 return; /* cannot happen */
1152         ecbdata->lno_in_postimage = strtol(p + 1, NULL, 10);
1153 }
1154
1155 static void fn_out_consume(void *priv, char *line, unsigned long len)
1156 {
1157         struct emit_callback *ecbdata = priv;
1158         const char *meta = diff_get_color(ecbdata->color_diff, DIFF_METAINFO);
1159         const char *plain = diff_get_color(ecbdata->color_diff, DIFF_PLAIN);
1160         const char *reset = diff_get_color(ecbdata->color_diff, DIFF_RESET);
1161         struct diff_options *o = ecbdata->opt;
1162         const char *line_prefix = diff_line_prefix(o);
1163
1164         if (ecbdata->header) {
1165                 fprintf(ecbdata->opt->file, "%s", ecbdata->header->buf);
1166                 strbuf_reset(ecbdata->header);
1167                 ecbdata->header = NULL;
1168         }
1169         *(ecbdata->found_changesp) = 1;
1170
1171         if (ecbdata->label_path[0]) {
1172                 const char *name_a_tab, *name_b_tab;
1173
1174                 name_a_tab = strchr(ecbdata->label_path[0], ' ') ? "\t" : "";
1175                 name_b_tab = strchr(ecbdata->label_path[1], ' ') ? "\t" : "";
1176
1177                 fprintf(ecbdata->opt->file, "%s%s--- %s%s%s\n",
1178                         line_prefix, meta, ecbdata->label_path[0], reset, name_a_tab);
1179                 fprintf(ecbdata->opt->file, "%s%s+++ %s%s%s\n",
1180                         line_prefix, meta, ecbdata->label_path[1], reset, name_b_tab);
1181                 ecbdata->label_path[0] = ecbdata->label_path[1] = NULL;
1182         }
1183
1184         if (diff_suppress_blank_empty
1185             && len == 2 && line[0] == ' ' && line[1] == '\n') {
1186                 line[0] = '\n';
1187                 len = 1;
1188         }
1189
1190         if (line[0] == '@') {
1191                 if (ecbdata->diff_words)
1192                         diff_words_flush(ecbdata);
1193                 len = sane_truncate_line(ecbdata, line, len);
1194                 find_lno(line, ecbdata);
1195                 emit_hunk_header(ecbdata, line, len);
1196                 if (line[len-1] != '\n')
1197                         putc('\n', ecbdata->opt->file);
1198                 return;
1199         }
1200
1201         if (len < 1) {
1202                 emit_line(ecbdata->opt, reset, reset, line, len);
1203                 if (ecbdata->diff_words
1204                     && ecbdata->diff_words->type == DIFF_WORDS_PORCELAIN)
1205                         fputs("~\n", ecbdata->opt->file);
1206                 return;
1207         }
1208
1209         if (ecbdata->diff_words) {
1210                 if (line[0] == '-') {
1211                         diff_words_append(line, len,
1212                                           &ecbdata->diff_words->minus);
1213                         return;
1214                 } else if (line[0] == '+') {
1215                         diff_words_append(line, len,
1216                                           &ecbdata->diff_words->plus);
1217                         return;
1218                 } else if (!prefixcmp(line, "\\ ")) {
1219                         /*
1220                          * Eat the "no newline at eof" marker as if we
1221                          * saw a "+" or "-" line with nothing on it,
1222                          * and return without diff_words_flush() to
1223                          * defer processing. If this is the end of
1224                          * preimage, more "+" lines may come after it.
1225                          */
1226                         return;
1227                 }
1228                 diff_words_flush(ecbdata);
1229                 if (ecbdata->diff_words->type == DIFF_WORDS_PORCELAIN) {
1230                         emit_line(ecbdata->opt, plain, reset, line, len);
1231                         fputs("~\n", ecbdata->opt->file);
1232                 } else {
1233                         /*
1234                          * Skip the prefix character, if any.  With
1235                          * diff_suppress_blank_empty, there may be
1236                          * none.
1237                          */
1238                         if (line[0] != '\n') {
1239                               line++;
1240                               len--;
1241                         }
1242                         emit_line(ecbdata->opt, plain, reset, line, len);
1243                 }
1244                 return;
1245         }
1246
1247         if (line[0] != '+') {
1248                 const char *color =
1249                         diff_get_color(ecbdata->color_diff,
1250                                        line[0] == '-' ? DIFF_FILE_OLD : DIFF_PLAIN);
1251                 ecbdata->lno_in_preimage++;
1252                 if (line[0] == ' ')
1253                         ecbdata->lno_in_postimage++;
1254                 emit_line(ecbdata->opt, color, reset, line, len);
1255         } else {
1256                 ecbdata->lno_in_postimage++;
1257                 emit_add_line(reset, ecbdata, line + 1, len - 1);
1258         }
1259 }
1260
1261 static char *pprint_rename(const char *a, const char *b)
1262 {
1263         const char *old = a;
1264         const char *new = b;
1265         struct strbuf name = STRBUF_INIT;
1266         int pfx_length, sfx_length;
1267         int pfx_adjust_for_slash;
1268         int len_a = strlen(a);
1269         int len_b = strlen(b);
1270         int a_midlen, b_midlen;
1271         int qlen_a = quote_c_style(a, NULL, NULL, 0);
1272         int qlen_b = quote_c_style(b, NULL, NULL, 0);
1273
1274         if (qlen_a || qlen_b) {
1275                 quote_c_style(a, &name, NULL, 0);
1276                 strbuf_addstr(&name, " => ");
1277                 quote_c_style(b, &name, NULL, 0);
1278                 return strbuf_detach(&name, NULL);
1279         }
1280
1281         /* Find common prefix */
1282         pfx_length = 0;
1283         while (*old && *new && *old == *new) {
1284                 if (*old == '/')
1285                         pfx_length = old - a + 1;
1286                 old++;
1287                 new++;
1288         }
1289
1290         /* Find common suffix */
1291         old = a + len_a;
1292         new = b + len_b;
1293         sfx_length = 0;
1294         /*
1295          * If there is a common prefix, it must end in a slash.  In
1296          * that case we let this loop run 1 into the prefix to see the
1297          * same slash.
1298          *
1299          * If there is no common prefix, we cannot do this as it would
1300          * underrun the input strings.
1301          */
1302         pfx_adjust_for_slash = (pfx_length ? 1 : 0);
1303         while (a + pfx_length - pfx_adjust_for_slash <= old &&
1304                b + pfx_length - pfx_adjust_for_slash <= new &&
1305                *old == *new) {
1306                 if (*old == '/')
1307                         sfx_length = len_a - (old - a);
1308                 old--;
1309                 new--;
1310         }
1311
1312         /*
1313          * pfx{mid-a => mid-b}sfx
1314          * {pfx-a => pfx-b}sfx
1315          * pfx{sfx-a => sfx-b}
1316          * name-a => name-b
1317          */
1318         a_midlen = len_a - pfx_length - sfx_length;
1319         b_midlen = len_b - pfx_length - sfx_length;
1320         if (a_midlen < 0)
1321                 a_midlen = 0;
1322         if (b_midlen < 0)
1323                 b_midlen = 0;
1324
1325         strbuf_grow(&name, pfx_length + a_midlen + b_midlen + sfx_length + 7);
1326         if (pfx_length + sfx_length) {
1327                 strbuf_add(&name, a, pfx_length);
1328                 strbuf_addch(&name, '{');
1329         }
1330         strbuf_add(&name, a + pfx_length, a_midlen);
1331         strbuf_addstr(&name, " => ");
1332         strbuf_add(&name, b + pfx_length, b_midlen);
1333         if (pfx_length + sfx_length) {
1334                 strbuf_addch(&name, '}');
1335                 strbuf_add(&name, a + len_a - sfx_length, sfx_length);
1336         }
1337         return strbuf_detach(&name, NULL);
1338 }
1339
1340 struct diffstat_t {
1341         int nr;
1342         int alloc;
1343         struct diffstat_file {
1344                 char *from_name;
1345                 char *name;
1346                 char *print_name;
1347                 unsigned is_unmerged:1;
1348                 unsigned is_binary:1;
1349                 unsigned is_renamed:1;
1350                 unsigned is_interesting:1;
1351                 uintmax_t added, deleted;
1352         } **files;
1353 };
1354
1355 static struct diffstat_file *diffstat_add(struct diffstat_t *diffstat,
1356                                           const char *name_a,
1357                                           const char *name_b)
1358 {
1359         struct diffstat_file *x;
1360         x = xcalloc(sizeof (*x), 1);
1361         if (diffstat->nr == diffstat->alloc) {
1362                 diffstat->alloc = alloc_nr(diffstat->alloc);
1363                 diffstat->files = xrealloc(diffstat->files,
1364                                 diffstat->alloc * sizeof(x));
1365         }
1366         diffstat->files[diffstat->nr++] = x;
1367         if (name_b) {
1368                 x->from_name = xstrdup(name_a);
1369                 x->name = xstrdup(name_b);
1370                 x->is_renamed = 1;
1371         }
1372         else {
1373                 x->from_name = NULL;
1374                 x->name = xstrdup(name_a);
1375         }
1376         return x;
1377 }
1378
1379 static void diffstat_consume(void *priv, char *line, unsigned long len)
1380 {
1381         struct diffstat_t *diffstat = priv;
1382         struct diffstat_file *x = diffstat->files[diffstat->nr - 1];
1383
1384         if (line[0] == '+')
1385                 x->added++;
1386         else if (line[0] == '-')
1387                 x->deleted++;
1388 }
1389
1390 const char mime_boundary_leader[] = "------------";
1391
1392 static int scale_linear(int it, int width, int max_change)
1393 {
1394         if (!it)
1395                 return 0;
1396         /*
1397          * make sure that at least one '-' or '+' is printed if
1398          * there is any change to this path. The easiest way is to
1399          * scale linearly as if the alloted width is one column shorter
1400          * than it is, and then add 1 to the result.
1401          */
1402         return 1 + (it * (width - 1) / max_change);
1403 }
1404
1405 static void show_name(FILE *file,
1406                       const char *prefix, const char *name, int len)
1407 {
1408         fprintf(file, " %s%-*s |", prefix, len, name);
1409 }
1410
1411 static void show_graph(FILE *file, char ch, int cnt, const char *set, const char *reset)
1412 {
1413         if (cnt <= 0)
1414                 return;
1415         fprintf(file, "%s", set);
1416         while (cnt--)
1417                 putc(ch, file);
1418         fprintf(file, "%s", reset);
1419 }
1420
1421 static void fill_print_name(struct diffstat_file *file)
1422 {
1423         char *pname;
1424
1425         if (file->print_name)
1426                 return;
1427
1428         if (!file->is_renamed) {
1429                 struct strbuf buf = STRBUF_INIT;
1430                 if (quote_c_style(file->name, &buf, NULL, 0)) {
1431                         pname = strbuf_detach(&buf, NULL);
1432                 } else {
1433                         pname = file->name;
1434                         strbuf_release(&buf);
1435                 }
1436         } else {
1437                 pname = pprint_rename(file->from_name, file->name);
1438         }
1439         file->print_name = pname;
1440 }
1441
1442 int print_stat_summary(FILE *fp, int files, int insertions, int deletions)
1443 {
1444         struct strbuf sb = STRBUF_INIT;
1445         int ret;
1446
1447         if (!files) {
1448                 assert(insertions == 0 && deletions == 0);
1449                 return fprintf(fp, "%s\n", " 0 files changed");
1450         }
1451
1452         strbuf_addf(&sb,
1453                     (files == 1) ? " %d file changed" : " %d files changed",
1454                     files);
1455
1456         /*
1457          * For binary diff, the caller may want to print "x files
1458          * changed" with insertions == 0 && deletions == 0.
1459          *
1460          * Not omitting "0 insertions(+), 0 deletions(-)" in this case
1461          * is probably less confusing (i.e skip over "2 files changed
1462          * but nothing about added/removed lines? Is this a bug in Git?").
1463          */
1464         if (insertions || deletions == 0) {
1465                 /*
1466                  * TRANSLATORS: "+" in (+) is a line addition marker;
1467                  * do not translate it.
1468                  */
1469                 strbuf_addf(&sb,
1470                             (insertions == 1) ? ", %d insertion(+)" : ", %d insertions(+)",
1471                             insertions);
1472         }
1473
1474         if (deletions || insertions == 0) {
1475                 /*
1476                  * TRANSLATORS: "-" in (-) is a line removal marker;
1477                  * do not translate it.
1478                  */
1479                 strbuf_addf(&sb,
1480                             (deletions == 1) ? ", %d deletion(-)" : ", %d deletions(-)",
1481                             deletions);
1482         }
1483         strbuf_addch(&sb, '\n');
1484         ret = fputs(sb.buf, fp);
1485         strbuf_release(&sb);
1486         return ret;
1487 }
1488
1489 static void show_stats(struct diffstat_t *data, struct diff_options *options)
1490 {
1491         int i, len, add, del, adds = 0, dels = 0;
1492         uintmax_t max_change = 0, max_len = 0;
1493         int total_files = data->nr, count;
1494         int width, name_width, graph_width, number_width = 0, bin_width = 0;
1495         const char *reset, *add_c, *del_c;
1496         const char *line_prefix = "";
1497         int extra_shown = 0;
1498
1499         if (data->nr == 0)
1500                 return;
1501
1502         line_prefix = diff_line_prefix(options);
1503         count = options->stat_count ? options->stat_count : data->nr;
1504
1505         reset = diff_get_color_opt(options, DIFF_RESET);
1506         add_c = diff_get_color_opt(options, DIFF_FILE_NEW);
1507         del_c = diff_get_color_opt(options, DIFF_FILE_OLD);
1508
1509         /*
1510          * Find the longest filename and max number of changes
1511          */
1512         for (i = 0; (i < count) && (i < data->nr); i++) {
1513                 struct diffstat_file *file = data->files[i];
1514                 uintmax_t change = file->added + file->deleted;
1515
1516                 if (!file->is_interesting && (change == 0)) {
1517                         count++; /* not shown == room for one more */
1518                         continue;
1519                 }
1520                 fill_print_name(file);
1521                 len = strlen(file->print_name);
1522                 if (max_len < len)
1523                         max_len = len;
1524
1525                 if (file->is_unmerged) {
1526                         /* "Unmerged" is 8 characters */
1527                         bin_width = bin_width < 8 ? 8 : bin_width;
1528                         continue;
1529                 }
1530                 if (file->is_binary) {
1531                         /* "Bin XXX -> YYY bytes" */
1532                         int w = 14 + decimal_width(file->added)
1533                                 + decimal_width(file->deleted);
1534                         bin_width = bin_width < w ? w : bin_width;
1535                         /* Display change counts aligned with "Bin" */
1536                         number_width = 3;
1537                         continue;
1538                 }
1539
1540                 if (max_change < change)
1541                         max_change = change;
1542         }
1543         count = i; /* where we can stop scanning in data->files[] */
1544
1545         /*
1546          * We have width = stat_width or term_columns() columns total.
1547          * We want a maximum of min(max_len, stat_name_width) for the name part.
1548          * We want a maximum of min(max_change, stat_graph_width) for the +- part.
1549          * We also need 1 for " " and 4 + decimal_width(max_change)
1550          * for " | NNNN " and one the empty column at the end, altogether
1551          * 6 + decimal_width(max_change).
1552          *
1553          * If there's not enough space, we will use the smaller of
1554          * stat_name_width (if set) and 5/8*width for the filename,
1555          * and the rest for constant elements + graph part, but no more
1556          * than stat_graph_width for the graph part.
1557          * (5/8 gives 50 for filename and 30 for the constant parts + graph
1558          * for the standard terminal size).
1559          *
1560          * In other words: stat_width limits the maximum width, and
1561          * stat_name_width fixes the maximum width of the filename,
1562          * and is also used to divide available columns if there
1563          * aren't enough.
1564          *
1565          * Binary files are displayed with "Bin XXX -> YYY bytes"
1566          * instead of the change count and graph. This part is treated
1567          * similarly to the graph part, except that it is not
1568          * "scaled". If total width is too small to accommodate the
1569          * guaranteed minimum width of the filename part and the
1570          * separators and this message, this message will "overflow"
1571          * making the line longer than the maximum width.
1572          */
1573
1574         if (options->stat_width == -1)
1575                 width = term_columns() - options->output_prefix_length;
1576         else
1577                 width = options->stat_width ? options->stat_width : 80;
1578         number_width = decimal_width(max_change) > number_width ?
1579                 decimal_width(max_change) : number_width;
1580
1581         if (options->stat_graph_width == -1)
1582                 options->stat_graph_width = diff_stat_graph_width;
1583
1584         /*
1585          * Guarantee 3/8*16==6 for the graph part
1586          * and 5/8*16==10 for the filename part
1587          */
1588         if (width < 16 + 6 + number_width)
1589                 width = 16 + 6 + number_width;
1590
1591         /*
1592          * First assign sizes that are wanted, ignoring available width.
1593          * strlen("Bin XXX -> YYY bytes") == bin_width, and the part
1594          * starting from "XXX" should fit in graph_width.
1595          */
1596         graph_width = max_change + 4 > bin_width ? max_change : bin_width - 4;
1597         if (options->stat_graph_width &&
1598             options->stat_graph_width < graph_width)
1599                 graph_width = options->stat_graph_width;
1600
1601         name_width = (options->stat_name_width > 0 &&
1602                       options->stat_name_width < max_len) ?
1603                 options->stat_name_width : max_len;
1604
1605         /*
1606          * Adjust adjustable widths not to exceed maximum width
1607          */
1608         if (name_width + number_width + 6 + graph_width > width) {
1609                 if (graph_width > width * 3/8 - number_width - 6) {
1610                         graph_width = width * 3/8 - number_width - 6;
1611                         if (graph_width < 6)
1612                                 graph_width = 6;
1613                 }
1614
1615                 if (options->stat_graph_width &&
1616                     graph_width > options->stat_graph_width)
1617                         graph_width = options->stat_graph_width;
1618                 if (name_width > width - number_width - 6 - graph_width)
1619                         name_width = width - number_width - 6 - graph_width;
1620                 else
1621                         graph_width = width - number_width - 6 - name_width;
1622         }
1623
1624         /*
1625          * From here name_width is the width of the name area,
1626          * and graph_width is the width of the graph area.
1627          * max_change is used to scale graph properly.
1628          */
1629         for (i = 0; i < count; i++) {
1630                 const char *prefix = "";
1631                 struct diffstat_file *file = data->files[i];
1632                 char *name = file->print_name;
1633                 uintmax_t added = file->added;
1634                 uintmax_t deleted = file->deleted;
1635                 int name_len;
1636
1637                 if (!file->is_interesting && (added + deleted == 0))
1638                         continue;
1639
1640                 /*
1641                  * "scale" the filename
1642                  */
1643                 len = name_width;
1644                 name_len = strlen(name);
1645                 if (name_width < name_len) {
1646                         char *slash;
1647                         prefix = "...";
1648                         len -= 3;
1649                         name += name_len - len;
1650                         slash = strchr(name, '/');
1651                         if (slash)
1652                                 name = slash;
1653                 }
1654
1655                 if (file->is_binary) {
1656                         fprintf(options->file, "%s", line_prefix);
1657                         show_name(options->file, prefix, name, len);
1658                         fprintf(options->file, " %*s", number_width, "Bin");
1659                         if (!added && !deleted) {
1660                                 putc('\n', options->file);
1661                                 continue;
1662                         }
1663                         fprintf(options->file, " %s%"PRIuMAX"%s",
1664                                 del_c, deleted, reset);
1665                         fprintf(options->file, " -> ");
1666                         fprintf(options->file, "%s%"PRIuMAX"%s",
1667                                 add_c, added, reset);
1668                         fprintf(options->file, " bytes");
1669                         fprintf(options->file, "\n");
1670                         continue;
1671                 }
1672                 else if (file->is_unmerged) {
1673                         fprintf(options->file, "%s", line_prefix);
1674                         show_name(options->file, prefix, name, len);
1675                         fprintf(options->file, " Unmerged\n");
1676                         continue;
1677                 }
1678
1679                 /*
1680                  * scale the add/delete
1681                  */
1682                 add = added;
1683                 del = deleted;
1684
1685                 if (graph_width <= max_change) {
1686                         int total = add + del;
1687
1688                         total = scale_linear(add + del, graph_width, max_change);
1689                         if (total < 2 && add && del)
1690                                 /* width >= 2 due to the sanity check */
1691                                 total = 2;
1692                         if (add < del) {
1693                                 add = scale_linear(add, graph_width, max_change);
1694                                 del = total - add;
1695                         } else {
1696                                 del = scale_linear(del, graph_width, max_change);
1697                                 add = total - del;
1698                         }
1699                 }
1700                 fprintf(options->file, "%s", line_prefix);
1701                 show_name(options->file, prefix, name, len);
1702                 fprintf(options->file, " %*"PRIuMAX"%s",
1703                         number_width, added + deleted,
1704                         added + deleted ? " " : "");
1705                 show_graph(options->file, '+', add, add_c, reset);
1706                 show_graph(options->file, '-', del, del_c, reset);
1707                 fprintf(options->file, "\n");
1708         }
1709
1710         for (i = 0; i < data->nr; i++) {
1711                 struct diffstat_file *file = data->files[i];
1712                 uintmax_t added = file->added;
1713                 uintmax_t deleted = file->deleted;
1714
1715                 if (file->is_unmerged ||
1716                     (!file->is_interesting && (added + deleted == 0))) {
1717                         total_files--;
1718                         continue;
1719                 }
1720
1721                 if (!file->is_binary) {
1722                         adds += added;
1723                         dels += deleted;
1724                 }
1725                 if (i < count)
1726                         continue;
1727                 if (!extra_shown)
1728                         fprintf(options->file, "%s ...\n", line_prefix);
1729                 extra_shown = 1;
1730         }
1731         fprintf(options->file, "%s", line_prefix);
1732         print_stat_summary(options->file, total_files, adds, dels);
1733 }
1734
1735 static void show_shortstats(struct diffstat_t *data, struct diff_options *options)
1736 {
1737         int i, adds = 0, dels = 0, total_files = data->nr;
1738
1739         if (data->nr == 0)
1740                 return;
1741
1742         for (i = 0; i < data->nr; i++) {
1743                 int added = data->files[i]->added;
1744                 int deleted= data->files[i]->deleted;
1745
1746                 if (data->files[i]->is_unmerged ||
1747                     (!data->files[i]->is_interesting && (added + deleted == 0))) {
1748                         total_files--;
1749                 } else if (!data->files[i]->is_binary) { /* don't count bytes */
1750                         adds += added;
1751                         dels += deleted;
1752                 }
1753         }
1754         fprintf(options->file, "%s", diff_line_prefix(options));
1755         print_stat_summary(options->file, total_files, adds, dels);
1756 }
1757
1758 static void show_numstat(struct diffstat_t *data, struct diff_options *options)
1759 {
1760         int i;
1761
1762         if (data->nr == 0)
1763                 return;
1764
1765         for (i = 0; i < data->nr; i++) {
1766                 struct diffstat_file *file = data->files[i];
1767
1768                 fprintf(options->file, "%s", diff_line_prefix(options));
1769
1770                 if (file->is_binary)
1771                         fprintf(options->file, "-\t-\t");
1772                 else
1773                         fprintf(options->file,
1774                                 "%"PRIuMAX"\t%"PRIuMAX"\t",
1775                                 file->added, file->deleted);
1776                 if (options->line_termination) {
1777                         fill_print_name(file);
1778                         if (!file->is_renamed)
1779                                 write_name_quoted(file->name, options->file,
1780                                                   options->line_termination);
1781                         else {
1782                                 fputs(file->print_name, options->file);
1783                                 putc(options->line_termination, options->file);
1784                         }
1785                 } else {
1786                         if (file->is_renamed) {
1787                                 putc('\0', options->file);
1788                                 write_name_quoted(file->from_name, options->file, '\0');
1789                         }
1790                         write_name_quoted(file->name, options->file, '\0');
1791                 }
1792         }
1793 }
1794
1795 struct dirstat_file {
1796         const char *name;
1797         unsigned long changed;
1798 };
1799
1800 struct dirstat_dir {
1801         struct dirstat_file *files;
1802         int alloc, nr, permille, cumulative;
1803 };
1804
1805 static long gather_dirstat(struct diff_options *opt, struct dirstat_dir *dir,
1806                 unsigned long changed, const char *base, int baselen)
1807 {
1808         unsigned long this_dir = 0;
1809         unsigned int sources = 0;
1810         const char *line_prefix = diff_line_prefix(opt);
1811
1812         while (dir->nr) {
1813                 struct dirstat_file *f = dir->files;
1814                 int namelen = strlen(f->name);
1815                 unsigned long this;
1816                 char *slash;
1817
1818                 if (namelen < baselen)
1819                         break;
1820                 if (memcmp(f->name, base, baselen))
1821                         break;
1822                 slash = strchr(f->name + baselen, '/');
1823                 if (slash) {
1824                         int newbaselen = slash + 1 - f->name;
1825                         this = gather_dirstat(opt, dir, changed, f->name, newbaselen);
1826                         sources++;
1827                 } else {
1828                         this = f->changed;
1829                         dir->files++;
1830                         dir->nr--;
1831                         sources += 2;
1832                 }
1833                 this_dir += this;
1834         }
1835
1836         /*
1837          * We don't report dirstat's for
1838          *  - the top level
1839          *  - or cases where everything came from a single directory
1840          *    under this directory (sources == 1).
1841          */
1842         if (baselen && sources != 1) {
1843                 if (this_dir) {
1844                         int permille = this_dir * 1000 / changed;
1845                         if (permille >= dir->permille) {
1846                                 fprintf(opt->file, "%s%4d.%01d%% %.*s\n", line_prefix,
1847                                         permille / 10, permille % 10, baselen, base);
1848                                 if (!dir->cumulative)
1849                                         return 0;
1850                         }
1851                 }
1852         }
1853         return this_dir;
1854 }
1855
1856 static int dirstat_compare(const void *_a, const void *_b)
1857 {
1858         const struct dirstat_file *a = _a;
1859         const struct dirstat_file *b = _b;
1860         return strcmp(a->name, b->name);
1861 }
1862
1863 static void show_dirstat(struct diff_options *options)
1864 {
1865         int i;
1866         unsigned long changed;
1867         struct dirstat_dir dir;
1868         struct diff_queue_struct *q = &diff_queued_diff;
1869
1870         dir.files = NULL;
1871         dir.alloc = 0;
1872         dir.nr = 0;
1873         dir.permille = options->dirstat_permille;
1874         dir.cumulative = DIFF_OPT_TST(options, DIRSTAT_CUMULATIVE);
1875
1876         changed = 0;
1877         for (i = 0; i < q->nr; i++) {
1878                 struct diff_filepair *p = q->queue[i];
1879                 const char *name;
1880                 unsigned long copied, added, damage;
1881                 int content_changed;
1882
1883                 name = p->two->path ? p->two->path : p->one->path;
1884
1885                 if (p->one->sha1_valid && p->two->sha1_valid)
1886                         content_changed = hashcmp(p->one->sha1, p->two->sha1);
1887                 else
1888                         content_changed = 1;
1889
1890                 if (!content_changed) {
1891                         /*
1892                          * The SHA1 has not changed, so pre-/post-content is
1893                          * identical. We can therefore skip looking at the
1894                          * file contents altogether.
1895                          */
1896                         damage = 0;
1897                         goto found_damage;
1898                 }
1899
1900                 if (DIFF_OPT_TST(options, DIRSTAT_BY_FILE)) {
1901                         /*
1902                          * In --dirstat-by-file mode, we don't really need to
1903                          * look at the actual file contents at all.
1904                          * The fact that the SHA1 changed is enough for us to
1905                          * add this file to the list of results
1906                          * (with each file contributing equal damage).
1907                          */
1908                         damage = 1;
1909                         goto found_damage;
1910                 }
1911
1912                 if (DIFF_FILE_VALID(p->one) && DIFF_FILE_VALID(p->two)) {
1913                         diff_populate_filespec(p->one, 0);
1914                         diff_populate_filespec(p->two, 0);
1915                         diffcore_count_changes(p->one, p->two, NULL, NULL, 0,
1916                                                &copied, &added);
1917                         diff_free_filespec_data(p->one);
1918                         diff_free_filespec_data(p->two);
1919                 } else if (DIFF_FILE_VALID(p->one)) {
1920                         diff_populate_filespec(p->one, 1);
1921                         copied = added = 0;
1922                         diff_free_filespec_data(p->one);
1923                 } else if (DIFF_FILE_VALID(p->two)) {
1924                         diff_populate_filespec(p->two, 1);
1925                         copied = 0;
1926                         added = p->two->size;
1927                         diff_free_filespec_data(p->two);
1928                 } else
1929                         continue;
1930
1931                 /*
1932                  * Original minus copied is the removed material,
1933                  * added is the new material.  They are both damages
1934                  * made to the preimage.
1935                  * If the resulting damage is zero, we know that
1936                  * diffcore_count_changes() considers the two entries to
1937                  * be identical, but since content_changed is true, we
1938                  * know that there must have been _some_ kind of change,
1939                  * so we force all entries to have damage > 0.
1940                  */
1941                 damage = (p->one->size - copied) + added;
1942                 if (!damage)
1943                         damage = 1;
1944
1945 found_damage:
1946                 ALLOC_GROW(dir.files, dir.nr + 1, dir.alloc);
1947                 dir.files[dir.nr].name = name;
1948                 dir.files[dir.nr].changed = damage;
1949                 changed += damage;
1950                 dir.nr++;
1951         }
1952
1953         /* This can happen even with many files, if everything was renames */
1954         if (!changed)
1955                 return;
1956
1957         /* Show all directories with more than x% of the changes */
1958         qsort(dir.files, dir.nr, sizeof(dir.files[0]), dirstat_compare);
1959         gather_dirstat(options, &dir, changed, "", 0);
1960 }
1961
1962 static void show_dirstat_by_line(struct diffstat_t *data, struct diff_options *options)
1963 {
1964         int i;
1965         unsigned long changed;
1966         struct dirstat_dir dir;
1967
1968         if (data->nr == 0)
1969                 return;
1970
1971         dir.files = NULL;
1972         dir.alloc = 0;
1973         dir.nr = 0;
1974         dir.permille = options->dirstat_permille;
1975         dir.cumulative = DIFF_OPT_TST(options, DIRSTAT_CUMULATIVE);
1976
1977         changed = 0;
1978         for (i = 0; i < data->nr; i++) {
1979                 struct diffstat_file *file = data->files[i];
1980                 unsigned long damage = file->added + file->deleted;
1981                 if (file->is_binary)
1982                         /*
1983                          * binary files counts bytes, not lines. Must find some
1984                          * way to normalize binary bytes vs. textual lines.
1985                          * The following heuristic assumes that there are 64
1986                          * bytes per "line".
1987                          * This is stupid and ugly, but very cheap...
1988                          */
1989                         damage = (damage + 63) / 64;
1990                 ALLOC_GROW(dir.files, dir.nr + 1, dir.alloc);
1991                 dir.files[dir.nr].name = file->name;
1992                 dir.files[dir.nr].changed = damage;
1993                 changed += damage;
1994                 dir.nr++;
1995         }
1996
1997         /* This can happen even with many files, if everything was renames */
1998         if (!changed)
1999                 return;
2000
2001         /* Show all directories with more than x% of the changes */
2002         qsort(dir.files, dir.nr, sizeof(dir.files[0]), dirstat_compare);
2003         gather_dirstat(options, &dir, changed, "", 0);
2004 }
2005
2006 static void free_diffstat_info(struct diffstat_t *diffstat)
2007 {
2008         int i;
2009         for (i = 0; i < diffstat->nr; i++) {
2010                 struct diffstat_file *f = diffstat->files[i];
2011                 if (f->name != f->print_name)
2012                         free(f->print_name);
2013                 free(f->name);
2014                 free(f->from_name);
2015                 free(f);
2016         }
2017         free(diffstat->files);
2018 }
2019
2020 struct checkdiff_t {
2021         const char *filename;
2022         int lineno;
2023         int conflict_marker_size;
2024         struct diff_options *o;
2025         unsigned ws_rule;
2026         unsigned status;
2027 };
2028
2029 static int is_conflict_marker(const char *line, int marker_size, unsigned long len)
2030 {
2031         char firstchar;
2032         int cnt;
2033
2034         if (len < marker_size + 1)
2035                 return 0;
2036         firstchar = line[0];
2037         switch (firstchar) {
2038         case '=': case '>': case '<': case '|':
2039                 break;
2040         default:
2041                 return 0;
2042         }
2043         for (cnt = 1; cnt < marker_size; cnt++)
2044                 if (line[cnt] != firstchar)
2045                         return 0;
2046         /* line[1] thru line[marker_size-1] are same as firstchar */
2047         if (len < marker_size + 1 || !isspace(line[marker_size]))
2048                 return 0;
2049         return 1;
2050 }
2051
2052 static void checkdiff_consume(void *priv, char *line, unsigned long len)
2053 {
2054         struct checkdiff_t *data = priv;
2055         int marker_size = data->conflict_marker_size;
2056         const char *ws = diff_get_color(data->o->use_color, DIFF_WHITESPACE);
2057         const char *reset = diff_get_color(data->o->use_color, DIFF_RESET);
2058         const char *set = diff_get_color(data->o->use_color, DIFF_FILE_NEW);
2059         char *err;
2060         const char *line_prefix;
2061
2062         assert(data->o);
2063         line_prefix = diff_line_prefix(data->o);
2064
2065         if (line[0] == '+') {
2066                 unsigned bad;
2067                 data->lineno++;
2068                 if (is_conflict_marker(line + 1, marker_size, len - 1)) {
2069                         data->status |= 1;
2070                         fprintf(data->o->file,
2071                                 "%s%s:%d: leftover conflict marker\n",
2072                                 line_prefix, data->filename, data->lineno);
2073                 }
2074                 bad = ws_check(line + 1, len - 1, data->ws_rule);
2075                 if (!bad)
2076                         return;
2077                 data->status |= bad;
2078                 err = whitespace_error_string(bad);
2079                 fprintf(data->o->file, "%s%s:%d: %s.\n",
2080                         line_prefix, data->filename, data->lineno, err);
2081                 free(err);
2082                 emit_line(data->o, set, reset, line, 1);
2083                 ws_check_emit(line + 1, len - 1, data->ws_rule,
2084                               data->o->file, set, reset, ws);
2085         } else if (line[0] == ' ') {
2086                 data->lineno++;
2087         } else if (line[0] == '@') {
2088                 char *plus = strchr(line, '+');
2089                 if (plus)
2090                         data->lineno = strtol(plus, NULL, 10) - 1;
2091                 else
2092                         die("invalid diff");
2093         }
2094 }
2095
2096 static unsigned char *deflate_it(char *data,
2097                                  unsigned long size,
2098                                  unsigned long *result_size)
2099 {
2100         int bound;
2101         unsigned char *deflated;
2102         git_zstream stream;
2103
2104         memset(&stream, 0, sizeof(stream));
2105         git_deflate_init(&stream, zlib_compression_level);
2106         bound = git_deflate_bound(&stream, size);
2107         deflated = xmalloc(bound);
2108         stream.next_out = deflated;
2109         stream.avail_out = bound;
2110
2111         stream.next_in = (unsigned char *)data;
2112         stream.avail_in = size;
2113         while (git_deflate(&stream, Z_FINISH) == Z_OK)
2114                 ; /* nothing */
2115         git_deflate_end(&stream);
2116         *result_size = stream.total_out;
2117         return deflated;
2118 }
2119
2120 static void emit_binary_diff_body(FILE *file, mmfile_t *one, mmfile_t *two,
2121                                   const char *prefix)
2122 {
2123         void *cp;
2124         void *delta;
2125         void *deflated;
2126         void *data;
2127         unsigned long orig_size;
2128         unsigned long delta_size;
2129         unsigned long deflate_size;
2130         unsigned long data_size;
2131
2132         /* We could do deflated delta, or we could do just deflated two,
2133          * whichever is smaller.
2134          */
2135         delta = NULL;
2136         deflated = deflate_it(two->ptr, two->size, &deflate_size);
2137         if (one->size && two->size) {
2138                 delta = diff_delta(one->ptr, one->size,
2139                                    two->ptr, two->size,
2140                                    &delta_size, deflate_size);
2141                 if (delta) {
2142                         void *to_free = delta;
2143                         orig_size = delta_size;
2144                         delta = deflate_it(delta, delta_size, &delta_size);
2145                         free(to_free);
2146                 }
2147         }
2148
2149         if (delta && delta_size < deflate_size) {
2150                 fprintf(file, "%sdelta %lu\n", prefix, orig_size);
2151                 free(deflated);
2152                 data = delta;
2153                 data_size = delta_size;
2154         }
2155         else {
2156                 fprintf(file, "%sliteral %lu\n", prefix, two->size);
2157                 free(delta);
2158                 data = deflated;
2159                 data_size = deflate_size;
2160         }
2161
2162         /* emit data encoded in base85 */
2163         cp = data;
2164         while (data_size) {
2165                 int bytes = (52 < data_size) ? 52 : data_size;
2166                 char line[70];
2167                 data_size -= bytes;
2168                 if (bytes <= 26)
2169                         line[0] = bytes + 'A' - 1;
2170                 else
2171                         line[0] = bytes - 26 + 'a' - 1;
2172                 encode_85(line + 1, cp, bytes);
2173                 cp = (char *) cp + bytes;
2174                 fprintf(file, "%s", prefix);
2175                 fputs(line, file);
2176                 fputc('\n', file);
2177         }
2178         fprintf(file, "%s\n", prefix);
2179         free(data);
2180 }
2181
2182 static void emit_binary_diff(FILE *file, mmfile_t *one, mmfile_t *two,
2183                              const char *prefix)
2184 {
2185         fprintf(file, "%sGIT binary patch\n", prefix);
2186         emit_binary_diff_body(file, one, two, prefix);
2187         emit_binary_diff_body(file, two, one, prefix);
2188 }
2189
2190 int diff_filespec_is_binary(struct diff_filespec *one)
2191 {
2192         if (one->is_binary == -1) {
2193                 diff_filespec_load_driver(one);
2194                 if (one->driver->binary != -1)
2195                         one->is_binary = one->driver->binary;
2196                 else {
2197                         if (!one->data && DIFF_FILE_VALID(one))
2198                                 diff_populate_filespec(one, 0);
2199                         if (one->data)
2200                                 one->is_binary = buffer_is_binary(one->data,
2201                                                 one->size);
2202                         if (one->is_binary == -1)
2203                                 one->is_binary = 0;
2204                 }
2205         }
2206         return one->is_binary;
2207 }
2208
2209 static const struct userdiff_funcname *diff_funcname_pattern(struct diff_filespec *one)
2210 {
2211         diff_filespec_load_driver(one);
2212         return one->driver->funcname.pattern ? &one->driver->funcname : NULL;
2213 }
2214
2215 void diff_set_mnemonic_prefix(struct diff_options *options, const char *a, const char *b)
2216 {
2217         if (!options->a_prefix)
2218                 options->a_prefix = a;
2219         if (!options->b_prefix)
2220                 options->b_prefix = b;
2221 }
2222
2223 struct userdiff_driver *get_textconv(struct diff_filespec *one)
2224 {
2225         if (!DIFF_FILE_VALID(one))
2226                 return NULL;
2227
2228         diff_filespec_load_driver(one);
2229         return userdiff_get_textconv(one->driver);
2230 }
2231
2232 static void builtin_diff(const char *name_a,
2233                          const char *name_b,
2234                          struct diff_filespec *one,
2235                          struct diff_filespec *two,
2236                          const char *xfrm_msg,
2237                          int must_show_header,
2238                          struct diff_options *o,
2239                          int complete_rewrite)
2240 {
2241         mmfile_t mf1, mf2;
2242         const char *lbl[2];
2243         char *a_one, *b_two;
2244         const char *meta = diff_get_color_opt(o, DIFF_METAINFO);
2245         const char *reset = diff_get_color_opt(o, DIFF_RESET);
2246         const char *a_prefix, *b_prefix;
2247         struct userdiff_driver *textconv_one = NULL;
2248         struct userdiff_driver *textconv_two = NULL;
2249         struct strbuf header = STRBUF_INIT;
2250         const char *line_prefix = diff_line_prefix(o);
2251
2252         if (DIFF_OPT_TST(o, SUBMODULE_LOG) &&
2253                         (!one->mode || S_ISGITLINK(one->mode)) &&
2254                         (!two->mode || S_ISGITLINK(two->mode))) {
2255                 const char *del = diff_get_color_opt(o, DIFF_FILE_OLD);
2256                 const char *add = diff_get_color_opt(o, DIFF_FILE_NEW);
2257                 show_submodule_summary(o->file, one ? one->path : two->path,
2258                                 line_prefix,
2259                                 one->sha1, two->sha1, two->dirty_submodule,
2260                                 meta, del, add, reset);
2261                 return;
2262         }
2263
2264         if (DIFF_OPT_TST(o, ALLOW_TEXTCONV)) {
2265                 textconv_one = get_textconv(one);
2266                 textconv_two = get_textconv(two);
2267         }
2268
2269         diff_set_mnemonic_prefix(o, "a/", "b/");
2270         if (DIFF_OPT_TST(o, REVERSE_DIFF)) {
2271                 a_prefix = o->b_prefix;
2272                 b_prefix = o->a_prefix;
2273         } else {
2274                 a_prefix = o->a_prefix;
2275                 b_prefix = o->b_prefix;
2276         }
2277
2278         /* Never use a non-valid filename anywhere if at all possible */
2279         name_a = DIFF_FILE_VALID(one) ? name_a : name_b;
2280         name_b = DIFF_FILE_VALID(two) ? name_b : name_a;
2281
2282         a_one = quote_two(a_prefix, name_a + (*name_a == '/'));
2283         b_two = quote_two(b_prefix, name_b + (*name_b == '/'));
2284         lbl[0] = DIFF_FILE_VALID(one) ? a_one : "/dev/null";
2285         lbl[1] = DIFF_FILE_VALID(two) ? b_two : "/dev/null";
2286         strbuf_addf(&header, "%s%sdiff --git %s %s%s\n", line_prefix, meta, a_one, b_two, reset);
2287         if (lbl[0][0] == '/') {
2288                 /* /dev/null */
2289                 strbuf_addf(&header, "%s%snew file mode %06o%s\n", line_prefix, meta, two->mode, reset);
2290                 if (xfrm_msg)
2291                         strbuf_addstr(&header, xfrm_msg);
2292                 must_show_header = 1;
2293         }
2294         else if (lbl[1][0] == '/') {
2295                 strbuf_addf(&header, "%s%sdeleted file mode %06o%s\n", line_prefix, meta, one->mode, reset);
2296                 if (xfrm_msg)
2297                         strbuf_addstr(&header, xfrm_msg);
2298                 must_show_header = 1;
2299         }
2300         else {
2301                 if (one->mode != two->mode) {
2302                         strbuf_addf(&header, "%s%sold mode %06o%s\n", line_prefix, meta, one->mode, reset);
2303                         strbuf_addf(&header, "%s%snew mode %06o%s\n", line_prefix, meta, two->mode, reset);
2304                         must_show_header = 1;
2305                 }
2306                 if (xfrm_msg)
2307                         strbuf_addstr(&header, xfrm_msg);
2308
2309                 /*
2310                  * we do not run diff between different kind
2311                  * of objects.
2312                  */
2313                 if ((one->mode ^ two->mode) & S_IFMT)
2314                         goto free_ab_and_return;
2315                 if (complete_rewrite &&
2316                     (textconv_one || !diff_filespec_is_binary(one)) &&
2317                     (textconv_two || !diff_filespec_is_binary(two))) {
2318                         fprintf(o->file, "%s", header.buf);
2319                         strbuf_reset(&header);
2320                         emit_rewrite_diff(name_a, name_b, one, two,
2321                                                 textconv_one, textconv_two, o);
2322                         o->found_changes = 1;
2323                         goto free_ab_and_return;
2324                 }
2325         }
2326
2327         if (o->irreversible_delete && lbl[1][0] == '/') {
2328                 fprintf(o->file, "%s", header.buf);
2329                 strbuf_reset(&header);
2330                 goto free_ab_and_return;
2331         } else if (!DIFF_OPT_TST(o, TEXT) &&
2332             ( (!textconv_one && diff_filespec_is_binary(one)) ||
2333               (!textconv_two && diff_filespec_is_binary(two)) )) {
2334                 if (fill_mmfile(&mf1, one) < 0 || fill_mmfile(&mf2, two) < 0)
2335                         die("unable to read files to diff");
2336                 /* Quite common confusing case */
2337                 if (mf1.size == mf2.size &&
2338                     !memcmp(mf1.ptr, mf2.ptr, mf1.size)) {
2339                         if (must_show_header)
2340                                 fprintf(o->file, "%s", header.buf);
2341                         goto free_ab_and_return;
2342                 }
2343                 fprintf(o->file, "%s", header.buf);
2344                 strbuf_reset(&header);
2345                 if (DIFF_OPT_TST(o, BINARY))
2346                         emit_binary_diff(o->file, &mf1, &mf2, line_prefix);
2347                 else
2348                         fprintf(o->file, "%sBinary files %s and %s differ\n",
2349                                 line_prefix, lbl[0], lbl[1]);
2350                 o->found_changes = 1;
2351         } else {
2352                 /* Crazy xdl interfaces.. */
2353                 const char *diffopts = getenv("GIT_DIFF_OPTS");
2354                 xpparam_t xpp;
2355                 xdemitconf_t xecfg;
2356                 struct emit_callback ecbdata;
2357                 const struct userdiff_funcname *pe;
2358
2359                 if (must_show_header) {
2360                         fprintf(o->file, "%s", header.buf);
2361                         strbuf_reset(&header);
2362                 }
2363
2364                 mf1.size = fill_textconv(textconv_one, one, &mf1.ptr);
2365                 mf2.size = fill_textconv(textconv_two, two, &mf2.ptr);
2366
2367                 pe = diff_funcname_pattern(one);
2368                 if (!pe)
2369                         pe = diff_funcname_pattern(two);
2370
2371                 memset(&xpp, 0, sizeof(xpp));
2372                 memset(&xecfg, 0, sizeof(xecfg));
2373                 memset(&ecbdata, 0, sizeof(ecbdata));
2374                 ecbdata.label_path = lbl;
2375                 ecbdata.color_diff = want_color(o->use_color);
2376                 ecbdata.found_changesp = &o->found_changes;
2377                 ecbdata.ws_rule = whitespace_rule(name_b ? name_b : name_a);
2378                 if (ecbdata.ws_rule & WS_BLANK_AT_EOF)
2379                         check_blank_at_eof(&mf1, &mf2, &ecbdata);
2380                 ecbdata.opt = o;
2381                 ecbdata.header = header.len ? &header : NULL;
2382                 xpp.flags = o->xdl_opts;
2383                 xecfg.ctxlen = o->context;
2384                 xecfg.interhunkctxlen = o->interhunkcontext;
2385                 xecfg.flags = XDL_EMIT_FUNCNAMES;
2386                 if (DIFF_OPT_TST(o, FUNCCONTEXT))
2387                         xecfg.flags |= XDL_EMIT_FUNCCONTEXT;
2388                 if (pe)
2389                         xdiff_set_find_func(&xecfg, pe->pattern, pe->cflags);
2390                 if (!diffopts)
2391                         ;
2392                 else if (!prefixcmp(diffopts, "--unified="))
2393                         xecfg.ctxlen = strtoul(diffopts + 10, NULL, 10);
2394                 else if (!prefixcmp(diffopts, "-u"))
2395                         xecfg.ctxlen = strtoul(diffopts + 2, NULL, 10);
2396                 if (o->word_diff)
2397                         init_diff_words_data(&ecbdata, o, one, two);
2398                 xdi_diff_outf(&mf1, &mf2, fn_out_consume, &ecbdata,
2399                               &xpp, &xecfg);
2400                 if (o->word_diff)
2401                         free_diff_words_data(&ecbdata);
2402                 if (textconv_one)
2403                         free(mf1.ptr);
2404                 if (textconv_two)
2405                         free(mf2.ptr);
2406                 xdiff_clear_find_func(&xecfg);
2407         }
2408
2409  free_ab_and_return:
2410         strbuf_release(&header);
2411         diff_free_filespec_data(one);
2412         diff_free_filespec_data(two);
2413         free(a_one);
2414         free(b_two);
2415         return;
2416 }
2417
2418 static void builtin_diffstat(const char *name_a, const char *name_b,
2419                              struct diff_filespec *one,
2420                              struct diff_filespec *two,
2421                              struct diffstat_t *diffstat,
2422                              struct diff_options *o,
2423                              struct diff_filepair *p)
2424 {
2425         mmfile_t mf1, mf2;
2426         struct diffstat_file *data;
2427         int same_contents;
2428         int complete_rewrite = 0;
2429
2430         if (!DIFF_PAIR_UNMERGED(p)) {
2431                 if (p->status == DIFF_STATUS_MODIFIED && p->score)
2432                         complete_rewrite = 1;
2433         }
2434
2435         data = diffstat_add(diffstat, name_a, name_b);
2436         data->is_interesting = p->status != DIFF_STATUS_UNKNOWN;
2437
2438         if (!one || !two) {
2439                 data->is_unmerged = 1;
2440                 return;
2441         }
2442
2443         same_contents = !hashcmp(one->sha1, two->sha1);
2444
2445         if (diff_filespec_is_binary(one) || diff_filespec_is_binary(two)) {
2446                 data->is_binary = 1;
2447                 if (same_contents) {
2448                         data->added = 0;
2449                         data->deleted = 0;
2450                 } else {
2451                         data->added = diff_filespec_size(two);
2452                         data->deleted = diff_filespec_size(one);
2453                 }
2454         }
2455
2456         else if (complete_rewrite) {
2457                 diff_populate_filespec(one, 0);
2458                 diff_populate_filespec(two, 0);
2459                 data->deleted = count_lines(one->data, one->size);
2460                 data->added = count_lines(two->data, two->size);
2461         }
2462
2463         else if (!same_contents) {
2464                 /* Crazy xdl interfaces.. */
2465                 xpparam_t xpp;
2466                 xdemitconf_t xecfg;
2467
2468                 if (fill_mmfile(&mf1, one) < 0 || fill_mmfile(&mf2, two) < 0)
2469                         die("unable to read files to diff");
2470
2471                 memset(&xpp, 0, sizeof(xpp));
2472                 memset(&xecfg, 0, sizeof(xecfg));
2473                 xpp.flags = o->xdl_opts;
2474                 xecfg.ctxlen = o->context;
2475                 xecfg.interhunkctxlen = o->interhunkcontext;
2476                 xdi_diff_outf(&mf1, &mf2, diffstat_consume, diffstat,
2477                               &xpp, &xecfg);
2478         }
2479
2480         diff_free_filespec_data(one);
2481         diff_free_filespec_data(two);
2482 }
2483
2484 static void builtin_checkdiff(const char *name_a, const char *name_b,
2485                               const char *attr_path,
2486                               struct diff_filespec *one,
2487                               struct diff_filespec *two,
2488                               struct diff_options *o)
2489 {
2490         mmfile_t mf1, mf2;
2491         struct checkdiff_t data;
2492
2493         if (!two)
2494                 return;
2495
2496         memset(&data, 0, sizeof(data));
2497         data.filename = name_b ? name_b : name_a;
2498         data.lineno = 0;
2499         data.o = o;
2500         data.ws_rule = whitespace_rule(attr_path);
2501         data.conflict_marker_size = ll_merge_marker_size(attr_path);
2502
2503         if (fill_mmfile(&mf1, one) < 0 || fill_mmfile(&mf2, two) < 0)
2504                 die("unable to read files to diff");
2505
2506         /*
2507          * All the other codepaths check both sides, but not checking
2508          * the "old" side here is deliberate.  We are checking the newly
2509          * introduced changes, and as long as the "new" side is text, we
2510          * can and should check what it introduces.
2511          */
2512         if (diff_filespec_is_binary(two))
2513                 goto free_and_return;
2514         else {
2515                 /* Crazy xdl interfaces.. */
2516                 xpparam_t xpp;
2517                 xdemitconf_t xecfg;
2518
2519                 memset(&xpp, 0, sizeof(xpp));
2520                 memset(&xecfg, 0, sizeof(xecfg));
2521                 xecfg.ctxlen = 1; /* at least one context line */
2522                 xpp.flags = 0;
2523                 xdi_diff_outf(&mf1, &mf2, checkdiff_consume, &data,
2524                               &xpp, &xecfg);
2525
2526                 if (data.ws_rule & WS_BLANK_AT_EOF) {
2527                         struct emit_callback ecbdata;
2528                         int blank_at_eof;
2529
2530                         ecbdata.ws_rule = data.ws_rule;
2531                         check_blank_at_eof(&mf1, &mf2, &ecbdata);
2532                         blank_at_eof = ecbdata.blank_at_eof_in_postimage;
2533
2534                         if (blank_at_eof) {
2535                                 static char *err;
2536                                 if (!err)
2537                                         err = whitespace_error_string(WS_BLANK_AT_EOF);
2538                                 fprintf(o->file, "%s:%d: %s.\n",
2539                                         data.filename, blank_at_eof, err);
2540                                 data.status = 1; /* report errors */
2541                         }
2542                 }
2543         }
2544  free_and_return:
2545         diff_free_filespec_data(one);
2546         diff_free_filespec_data(two);
2547         if (data.status)
2548                 DIFF_OPT_SET(o, CHECK_FAILED);
2549 }
2550
2551 struct diff_filespec *alloc_filespec(const char *path)
2552 {
2553         int namelen = strlen(path);
2554         struct diff_filespec *spec = xmalloc(sizeof(*spec) + namelen + 1);
2555
2556         memset(spec, 0, sizeof(*spec));
2557         spec->path = (char *)(spec + 1);
2558         memcpy(spec->path, path, namelen+1);
2559         spec->count = 1;
2560         spec->is_binary = -1;
2561         return spec;
2562 }
2563
2564 void free_filespec(struct diff_filespec *spec)
2565 {
2566         if (!--spec->count) {
2567                 diff_free_filespec_data(spec);
2568                 free(spec);
2569         }
2570 }
2571
2572 void fill_filespec(struct diff_filespec *spec, const unsigned char *sha1,
2573                    int sha1_valid, unsigned short mode)
2574 {
2575         if (mode) {
2576                 spec->mode = canon_mode(mode);
2577                 hashcpy(spec->sha1, sha1);
2578                 spec->sha1_valid = sha1_valid;
2579         }
2580 }
2581
2582 /*
2583  * Given a name and sha1 pair, if the index tells us the file in
2584  * the work tree has that object contents, return true, so that
2585  * prepare_temp_file() does not have to inflate and extract.
2586  */
2587 static int reuse_worktree_file(const char *name, const unsigned char *sha1, int want_file)
2588 {
2589         struct cache_entry *ce;
2590         struct stat st;
2591         int pos, len;
2592
2593         /*
2594          * We do not read the cache ourselves here, because the
2595          * benchmark with my previous version that always reads cache
2596          * shows that it makes things worse for diff-tree comparing
2597          * two linux-2.6 kernel trees in an already checked out work
2598          * tree.  This is because most diff-tree comparisons deal with
2599          * only a small number of files, while reading the cache is
2600          * expensive for a large project, and its cost outweighs the
2601          * savings we get by not inflating the object to a temporary
2602          * file.  Practically, this code only helps when we are used
2603          * by diff-cache --cached, which does read the cache before
2604          * calling us.
2605          */
2606         if (!active_cache)
2607                 return 0;
2608
2609         /* We want to avoid the working directory if our caller
2610          * doesn't need the data in a normal file, this system
2611          * is rather slow with its stat/open/mmap/close syscalls,
2612          * and the object is contained in a pack file.  The pack
2613          * is probably already open and will be faster to obtain
2614          * the data through than the working directory.  Loose
2615          * objects however would tend to be slower as they need
2616          * to be individually opened and inflated.
2617          */
2618         if (!FAST_WORKING_DIRECTORY && !want_file && has_sha1_pack(sha1))
2619                 return 0;
2620
2621         len = strlen(name);
2622         pos = cache_name_pos(name, len);
2623         if (pos < 0)
2624                 return 0;
2625         ce = active_cache[pos];
2626
2627         /*
2628          * This is not the sha1 we are looking for, or
2629          * unreusable because it is not a regular file.
2630          */
2631         if (hashcmp(sha1, ce->sha1) || !S_ISREG(ce->ce_mode))
2632                 return 0;
2633
2634         /*
2635          * If ce is marked as "assume unchanged", there is no
2636          * guarantee that work tree matches what we are looking for.
2637          */
2638         if ((ce->ce_flags & CE_VALID) || ce_skip_worktree(ce))
2639                 return 0;
2640
2641         /*
2642          * If ce matches the file in the work tree, we can reuse it.
2643          */
2644         if (ce_uptodate(ce) ||
2645             (!lstat(name, &st) && !ce_match_stat(ce, &st, 0)))
2646                 return 1;
2647
2648         return 0;
2649 }
2650
2651 static int diff_populate_gitlink(struct diff_filespec *s, int size_only)
2652 {
2653         int len;
2654         char *data = xmalloc(100), *dirty = "";
2655
2656         /* Are we looking at the work tree? */
2657         if (s->dirty_submodule)
2658                 dirty = "-dirty";
2659
2660         len = snprintf(data, 100,
2661                        "Subproject commit %s%s\n", sha1_to_hex(s->sha1), dirty);
2662         s->data = data;
2663         s->size = len;
2664         s->should_free = 1;
2665         if (size_only) {
2666                 s->data = NULL;
2667                 free(data);
2668         }
2669         return 0;
2670 }
2671
2672 /*
2673  * While doing rename detection and pickaxe operation, we may need to
2674  * grab the data for the blob (or file) for our own in-core comparison.
2675  * diff_filespec has data and size fields for this purpose.
2676  */
2677 int diff_populate_filespec(struct diff_filespec *s, int size_only)
2678 {
2679         int err = 0;
2680         if (!DIFF_FILE_VALID(s))
2681                 die("internal error: asking to populate invalid file.");
2682         if (S_ISDIR(s->mode))
2683                 return -1;
2684
2685         if (s->data)
2686                 return 0;
2687
2688         if (size_only && 0 < s->size)
2689                 return 0;
2690
2691         if (S_ISGITLINK(s->mode))
2692                 return diff_populate_gitlink(s, size_only);
2693
2694         if (!s->sha1_valid ||
2695             reuse_worktree_file(s->path, s->sha1, 0)) {
2696                 struct strbuf buf = STRBUF_INIT;
2697                 struct stat st;
2698                 int fd;
2699
2700                 if (lstat(s->path, &st) < 0) {
2701                         if (errno == ENOENT) {
2702                         err_empty:
2703                                 err = -1;
2704                         empty:
2705                                 s->data = (char *)"";
2706                                 s->size = 0;
2707                                 return err;
2708                         }
2709                 }
2710                 s->size = xsize_t(st.st_size);
2711                 if (!s->size)
2712                         goto empty;
2713                 if (S_ISLNK(st.st_mode)) {
2714                         struct strbuf sb = STRBUF_INIT;
2715
2716                         if (strbuf_readlink(&sb, s->path, s->size))
2717                                 goto err_empty;
2718                         s->size = sb.len;
2719                         s->data = strbuf_detach(&sb, NULL);
2720                         s->should_free = 1;
2721                         return 0;
2722                 }
2723                 if (size_only)
2724                         return 0;
2725                 fd = open(s->path, O_RDONLY);
2726                 if (fd < 0)
2727                         goto err_empty;
2728                 s->data = xmmap(NULL, s->size, PROT_READ, MAP_PRIVATE, fd, 0);
2729                 close(fd);
2730                 s->should_munmap = 1;
2731
2732                 /*
2733                  * Convert from working tree format to canonical git format
2734                  */
2735                 if (convert_to_git(s->path, s->data, s->size, &buf, safe_crlf)) {
2736                         size_t size = 0;
2737                         munmap(s->data, s->size);
2738                         s->should_munmap = 0;
2739                         s->data = strbuf_detach(&buf, &size);
2740                         s->size = size;
2741                         s->should_free = 1;
2742                 }
2743         }
2744         else {
2745                 enum object_type type;
2746                 if (size_only) {
2747                         type = sha1_object_info(s->sha1, &s->size);
2748                         if (type < 0)
2749                                 die("unable to read %s", sha1_to_hex(s->sha1));
2750                 } else {
2751                         s->data = read_sha1_file(s->sha1, &type, &s->size);
2752                         if (!s->data)
2753                                 die("unable to read %s", sha1_to_hex(s->sha1));
2754                         s->should_free = 1;
2755                 }
2756         }
2757         return 0;
2758 }
2759
2760 void diff_free_filespec_blob(struct diff_filespec *s)
2761 {
2762         if (s->should_free)
2763                 free(s->data);
2764         else if (s->should_munmap)
2765                 munmap(s->data, s->size);
2766
2767         if (s->should_free || s->should_munmap) {
2768                 s->should_free = s->should_munmap = 0;
2769                 s->data = NULL;
2770         }
2771 }
2772
2773 void diff_free_filespec_data(struct diff_filespec *s)
2774 {
2775         diff_free_filespec_blob(s);
2776         free(s->cnt_data);
2777         s->cnt_data = NULL;
2778 }
2779
2780 static void prep_temp_blob(const char *path, struct diff_tempfile *temp,
2781                            void *blob,
2782                            unsigned long size,
2783                            const unsigned char *sha1,
2784                            int mode)
2785 {
2786         int fd;
2787         struct strbuf buf = STRBUF_INIT;
2788         struct strbuf template = STRBUF_INIT;
2789         char *path_dup = xstrdup(path);
2790         const char *base = basename(path_dup);
2791
2792         /* Generate "XXXXXX_basename.ext" */
2793         strbuf_addstr(&template, "XXXXXX_");
2794         strbuf_addstr(&template, base);
2795
2796         fd = git_mkstemps(temp->tmp_path, PATH_MAX, template.buf,
2797                         strlen(base) + 1);
2798         if (fd < 0)
2799                 die_errno("unable to create temp-file");
2800         if (convert_to_working_tree(path,
2801                         (const char *)blob, (size_t)size, &buf)) {
2802                 blob = buf.buf;
2803                 size = buf.len;
2804         }
2805         if (write_in_full(fd, blob, size) != size)
2806                 die_errno("unable to write temp-file");
2807         close(fd);
2808         temp->name = temp->tmp_path;
2809         strcpy(temp->hex, sha1_to_hex(sha1));
2810         temp->hex[40] = 0;
2811         sprintf(temp->mode, "%06o", mode);
2812         strbuf_release(&buf);
2813         strbuf_release(&template);
2814         free(path_dup);
2815 }
2816
2817 static struct diff_tempfile *prepare_temp_file(const char *name,
2818                 struct diff_filespec *one)
2819 {
2820         struct diff_tempfile *temp = claim_diff_tempfile();
2821
2822         if (!DIFF_FILE_VALID(one)) {
2823         not_a_valid_file:
2824                 /* A '-' entry produces this for file-2, and
2825                  * a '+' entry produces this for file-1.
2826                  */
2827                 temp->name = "/dev/null";
2828                 strcpy(temp->hex, ".");
2829                 strcpy(temp->mode, ".");
2830                 return temp;
2831         }
2832
2833         if (!remove_tempfile_installed) {
2834                 atexit(remove_tempfile);
2835                 sigchain_push_common(remove_tempfile_on_signal);
2836                 remove_tempfile_installed = 1;
2837         }
2838
2839         if (!one->sha1_valid ||
2840             reuse_worktree_file(name, one->sha1, 1)) {
2841                 struct stat st;
2842                 if (lstat(name, &st) < 0) {
2843                         if (errno == ENOENT)
2844                                 goto not_a_valid_file;
2845                         die_errno("stat(%s)", name);
2846                 }
2847                 if (S_ISLNK(st.st_mode)) {
2848                         struct strbuf sb = STRBUF_INIT;
2849                         if (strbuf_readlink(&sb, name, st.st_size) < 0)
2850                                 die_errno("readlink(%s)", name);
2851                         prep_temp_blob(name, temp, sb.buf, sb.len,
2852                                        (one->sha1_valid ?
2853                                         one->sha1 : null_sha1),
2854                                        (one->sha1_valid ?
2855                                         one->mode : S_IFLNK));
2856                         strbuf_release(&sb);
2857                 }
2858                 else {
2859                         /* we can borrow from the file in the work tree */
2860                         temp->name = name;
2861                         if (!one->sha1_valid)
2862                                 strcpy(temp->hex, sha1_to_hex(null_sha1));
2863                         else
2864                                 strcpy(temp->hex, sha1_to_hex(one->sha1));
2865                         /* Even though we may sometimes borrow the
2866                          * contents from the work tree, we always want
2867                          * one->mode.  mode is trustworthy even when
2868                          * !(one->sha1_valid), as long as
2869                          * DIFF_FILE_VALID(one).
2870                          */
2871                         sprintf(temp->mode, "%06o", one->mode);
2872                 }
2873                 return temp;
2874         }
2875         else {
2876                 if (diff_populate_filespec(one, 0))
2877                         die("cannot read data blob for %s", one->path);
2878                 prep_temp_blob(name, temp, one->data, one->size,
2879                                one->sha1, one->mode);
2880         }
2881         return temp;
2882 }
2883
2884 /* An external diff command takes:
2885  *
2886  * diff-cmd name infile1 infile1-sha1 infile1-mode \
2887  *               infile2 infile2-sha1 infile2-mode [ rename-to ]
2888  *
2889  */
2890 static void run_external_diff(const char *pgm,
2891                               const char *name,
2892                               const char *other,
2893                               struct diff_filespec *one,
2894                               struct diff_filespec *two,
2895                               const char *xfrm_msg,
2896                               int complete_rewrite)
2897 {
2898         const char *spawn_arg[10];
2899         int retval;
2900         const char **arg = &spawn_arg[0];
2901
2902         if (one && two) {
2903                 struct diff_tempfile *temp_one, *temp_two;
2904                 const char *othername = (other ? other : name);
2905                 temp_one = prepare_temp_file(name, one);
2906                 temp_two = prepare_temp_file(othername, two);
2907                 *arg++ = pgm;
2908                 *arg++ = name;
2909                 *arg++ = temp_one->name;
2910                 *arg++ = temp_one->hex;
2911                 *arg++ = temp_one->mode;
2912                 *arg++ = temp_two->name;
2913                 *arg++ = temp_two->hex;
2914                 *arg++ = temp_two->mode;
2915                 if (other) {
2916                         *arg++ = other;
2917                         *arg++ = xfrm_msg;
2918                 }
2919         } else {
2920                 *arg++ = pgm;
2921                 *arg++ = name;
2922         }
2923         *arg = NULL;
2924         fflush(NULL);
2925         retval = run_command_v_opt(spawn_arg, RUN_USING_SHELL);
2926         remove_tempfile();
2927         if (retval) {
2928                 fprintf(stderr, "external diff died, stopping at %s.\n", name);
2929                 exit(1);
2930         }
2931 }
2932
2933 static int similarity_index(struct diff_filepair *p)
2934 {
2935         return p->score * 100 / MAX_SCORE;
2936 }
2937
2938 static void fill_metainfo(struct strbuf *msg,
2939                           const char *name,
2940                           const char *other,
2941                           struct diff_filespec *one,
2942                           struct diff_filespec *two,
2943                           struct diff_options *o,
2944                           struct diff_filepair *p,
2945                           int *must_show_header,
2946                           int use_color)
2947 {
2948         const char *set = diff_get_color(use_color, DIFF_METAINFO);
2949         const char *reset = diff_get_color(use_color, DIFF_RESET);
2950         const char *line_prefix = diff_line_prefix(o);
2951
2952         *must_show_header = 1;
2953         strbuf_init(msg, PATH_MAX * 2 + 300);
2954         switch (p->status) {
2955         case DIFF_STATUS_COPIED:
2956                 strbuf_addf(msg, "%s%ssimilarity index %d%%",
2957                             line_prefix, set, similarity_index(p));
2958                 strbuf_addf(msg, "%s\n%s%scopy from ",
2959                             reset,  line_prefix, set);
2960                 quote_c_style(name, msg, NULL, 0);
2961                 strbuf_addf(msg, "%s\n%s%scopy to ", reset, line_prefix, set);
2962                 quote_c_style(other, msg, NULL, 0);
2963                 strbuf_addf(msg, "%s\n", reset);
2964                 break;
2965         case DIFF_STATUS_RENAMED:
2966                 strbuf_addf(msg, "%s%ssimilarity index %d%%",
2967                             line_prefix, set, similarity_index(p));
2968                 strbuf_addf(msg, "%s\n%s%srename from ",
2969                             reset, line_prefix, set);
2970                 quote_c_style(name, msg, NULL, 0);
2971                 strbuf_addf(msg, "%s\n%s%srename to ",
2972                             reset, line_prefix, set);
2973                 quote_c_style(other, msg, NULL, 0);
2974                 strbuf_addf(msg, "%s\n", reset);
2975                 break;
2976         case DIFF_STATUS_MODIFIED:
2977                 if (p->score) {
2978                         strbuf_addf(msg, "%s%sdissimilarity index %d%%%s\n",
2979                                     line_prefix,
2980                                     set, similarity_index(p), reset);
2981                         break;
2982                 }
2983                 /* fallthru */
2984         default:
2985                 *must_show_header = 0;
2986         }
2987         if (one && two && hashcmp(one->sha1, two->sha1)) {
2988                 int abbrev = DIFF_OPT_TST(o, FULL_INDEX) ? 40 : DEFAULT_ABBREV;
2989
2990                 if (DIFF_OPT_TST(o, BINARY)) {
2991                         mmfile_t mf;
2992                         if ((!fill_mmfile(&mf, one) && diff_filespec_is_binary(one)) ||
2993                             (!fill_mmfile(&mf, two) && diff_filespec_is_binary(two)))
2994                                 abbrev = 40;
2995                 }
2996                 strbuf_addf(msg, "%s%sindex %s..", line_prefix, set,
2997                             find_unique_abbrev(one->sha1, abbrev));
2998                 strbuf_addstr(msg, find_unique_abbrev(two->sha1, abbrev));
2999                 if (one->mode == two->mode)
3000                         strbuf_addf(msg, " %06o", one->mode);
3001                 strbuf_addf(msg, "%s\n", reset);
3002         }
3003 }
3004
3005 static void run_diff_cmd(const char *pgm,
3006                          const char *name,
3007                          const char *other,
3008                          const char *attr_path,
3009                          struct diff_filespec *one,
3010                          struct diff_filespec *two,
3011                          struct strbuf *msg,
3012                          struct diff_options *o,
3013                          struct diff_filepair *p)
3014 {
3015         const char *xfrm_msg = NULL;
3016         int complete_rewrite = (p->status == DIFF_STATUS_MODIFIED) && p->score;
3017         int must_show_header = 0;
3018
3019
3020         if (DIFF_OPT_TST(o, ALLOW_EXTERNAL)) {
3021                 struct userdiff_driver *drv = userdiff_find_by_path(attr_path);
3022                 if (drv && drv->external)
3023                         pgm = drv->external;
3024         }
3025
3026         if (msg) {
3027                 /*
3028                  * don't use colors when the header is intended for an
3029                  * external diff driver
3030                  */
3031                 fill_metainfo(msg, name, other, one, two, o, p,
3032                               &must_show_header,
3033                               want_color(o->use_color) && !pgm);
3034                 xfrm_msg = msg->len ? msg->buf : NULL;
3035         }
3036
3037         if (pgm) {
3038                 run_external_diff(pgm, name, other, one, two, xfrm_msg,
3039                                   complete_rewrite);
3040                 return;
3041         }
3042         if (one && two)
3043                 builtin_diff(name, other ? other : name,
3044                              one, two, xfrm_msg, must_show_header,
3045                              o, complete_rewrite);
3046         else
3047                 fprintf(o->file, "* Unmerged path %s\n", name);
3048 }
3049
3050 static void diff_fill_sha1_info(struct diff_filespec *one)
3051 {
3052         if (DIFF_FILE_VALID(one)) {
3053                 if (!one->sha1_valid) {
3054                         struct stat st;
3055                         if (one->is_stdin) {
3056                                 hashcpy(one->sha1, null_sha1);
3057                                 return;
3058                         }
3059                         if (lstat(one->path, &st) < 0)
3060                                 die_errno("stat '%s'", one->path);
3061                         if (index_path(one->sha1, one->path, &st, 0))
3062                                 die("cannot hash %s", one->path);
3063                 }
3064         }
3065         else
3066                 hashclr(one->sha1);
3067 }
3068
3069 static void strip_prefix(int prefix_length, const char **namep, const char **otherp)
3070 {
3071         /* Strip the prefix but do not molest /dev/null and absolute paths */
3072         if (*namep && **namep != '/') {
3073                 *namep += prefix_length;
3074                 if (**namep == '/')
3075                         ++*namep;
3076         }
3077         if (*otherp && **otherp != '/') {
3078                 *otherp += prefix_length;
3079                 if (**otherp == '/')
3080                         ++*otherp;
3081         }
3082 }
3083
3084 static void run_diff(struct diff_filepair *p, struct diff_options *o)
3085 {
3086         const char *pgm = external_diff();
3087         struct strbuf msg;
3088         struct diff_filespec *one = p->one;
3089         struct diff_filespec *two = p->two;
3090         const char *name;
3091         const char *other;
3092         const char *attr_path;
3093
3094         name  = p->one->path;
3095         other = (strcmp(name, p->two->path) ? p->two->path : NULL);
3096         attr_path = name;
3097         if (o->prefix_length)
3098                 strip_prefix(o->prefix_length, &name, &other);
3099
3100         if (!DIFF_OPT_TST(o, ALLOW_EXTERNAL))
3101                 pgm = NULL;
3102
3103         if (DIFF_PAIR_UNMERGED(p)) {
3104                 run_diff_cmd(pgm, name, NULL, attr_path,
3105                              NULL, NULL, NULL, o, p);
3106                 return;
3107         }
3108
3109         diff_fill_sha1_info(one);
3110         diff_fill_sha1_info(two);
3111
3112         if (!pgm &&
3113             DIFF_FILE_VALID(one) && DIFF_FILE_VALID(two) &&
3114             (S_IFMT & one->mode) != (S_IFMT & two->mode)) {
3115                 /*
3116                  * a filepair that changes between file and symlink
3117                  * needs to be split into deletion and creation.
3118                  */
3119                 struct diff_filespec *null = alloc_filespec(two->path);
3120                 run_diff_cmd(NULL, name, other, attr_path,
3121                              one, null, &msg, o, p);
3122                 free(null);
3123                 strbuf_release(&msg);
3124
3125                 null = alloc_filespec(one->path);
3126                 run_diff_cmd(NULL, name, other, attr_path,
3127                              null, two, &msg, o, p);
3128                 free(null);
3129         }
3130         else
3131                 run_diff_cmd(pgm, name, other, attr_path,
3132                              one, two, &msg, o, p);
3133
3134         strbuf_release(&msg);
3135 }
3136
3137 static void run_diffstat(struct diff_filepair *p, struct diff_options *o,
3138                          struct diffstat_t *diffstat)
3139 {
3140         const char *name;
3141         const char *other;
3142
3143         if (DIFF_PAIR_UNMERGED(p)) {
3144                 /* unmerged */
3145                 builtin_diffstat(p->one->path, NULL, NULL, NULL, diffstat, o, p);
3146                 return;
3147         }
3148
3149         name = p->one->path;
3150         other = (strcmp(name, p->two->path) ? p->two->path : NULL);
3151
3152         if (o->prefix_length)
3153                 strip_prefix(o->prefix_length, &name, &other);
3154
3155         diff_fill_sha1_info(p->one);
3156         diff_fill_sha1_info(p->two);
3157
3158         builtin_diffstat(name, other, p->one, p->two, diffstat, o, p);
3159 }
3160
3161 static void run_checkdiff(struct diff_filepair *p, struct diff_options *o)
3162 {
3163         const char *name;
3164         const char *other;
3165         const char *attr_path;
3166
3167         if (DIFF_PAIR_UNMERGED(p)) {
3168                 /* unmerged */
3169                 return;
3170         }
3171
3172         name = p->one->path;
3173         other = (strcmp(name, p->two->path) ? p->two->path : NULL);
3174         attr_path = other ? other : name;
3175
3176         if (o->prefix_length)
3177                 strip_prefix(o->prefix_length, &name, &other);
3178
3179         diff_fill_sha1_info(p->one);
3180         diff_fill_sha1_info(p->two);
3181
3182         builtin_checkdiff(name, other, attr_path, p->one, p->two, o);
3183 }
3184
3185 void diff_setup(struct diff_options *options)
3186 {
3187         memcpy(options, &default_diff_options, sizeof(*options));
3188
3189         options->file = stdout;
3190
3191         options->line_termination = '\n';
3192         options->break_opt = -1;
3193         options->rename_limit = -1;
3194         options->dirstat_permille = diff_dirstat_permille_default;
3195         options->context = diff_context_default;
3196         DIFF_OPT_SET(options, RENAME_EMPTY);
3197
3198         options->change = diff_change;
3199         options->add_remove = diff_addremove;
3200         options->use_color = diff_use_color_default;
3201         options->detect_rename = diff_detect_rename_default;
3202         options->xdl_opts |= diff_algorithm;
3203
3204         if (diff_no_prefix) {
3205                 options->a_prefix = options->b_prefix = "";
3206         } else if (!diff_mnemonic_prefix) {
3207                 options->a_prefix = "a/";
3208                 options->b_prefix = "b/";
3209         }
3210 }
3211
3212 void diff_setup_done(struct diff_options *options)
3213 {
3214         int count = 0;
3215
3216         if (options->output_format & DIFF_FORMAT_NAME)
3217                 count++;
3218         if (options->output_format & DIFF_FORMAT_NAME_STATUS)
3219                 count++;
3220         if (options->output_format & DIFF_FORMAT_CHECKDIFF)
3221                 count++;
3222         if (options->output_format & DIFF_FORMAT_NO_OUTPUT)
3223                 count++;
3224         if (count > 1)
3225                 die("--name-only, --name-status, --check and -s are mutually exclusive");
3226
3227         /*
3228          * Most of the time we can say "there are changes"
3229          * only by checking if there are changed paths, but
3230          * --ignore-whitespace* options force us to look
3231          * inside contents.
3232          */
3233
3234         if (DIFF_XDL_TST(options, IGNORE_WHITESPACE) ||
3235             DIFF_XDL_TST(options, IGNORE_WHITESPACE_CHANGE) ||
3236             DIFF_XDL_TST(options, IGNORE_WHITESPACE_AT_EOL))
3237                 DIFF_OPT_SET(options, DIFF_FROM_CONTENTS);
3238         else
3239                 DIFF_OPT_CLR(options, DIFF_FROM_CONTENTS);
3240
3241         if (DIFF_OPT_TST(options, FIND_COPIES_HARDER))
3242                 options->detect_rename = DIFF_DETECT_COPY;
3243
3244         if (!DIFF_OPT_TST(options, RELATIVE_NAME))
3245                 options->prefix = NULL;
3246         if (options->prefix)
3247                 options->prefix_length = strlen(options->prefix);
3248         else
3249                 options->prefix_length = 0;
3250
3251         if (options->output_format & (DIFF_FORMAT_NAME |
3252                                       DIFF_FORMAT_NAME_STATUS |
3253                                       DIFF_FORMAT_CHECKDIFF |
3254                                       DIFF_FORMAT_NO_OUTPUT))
3255                 options->output_format &= ~(DIFF_FORMAT_RAW |
3256                                             DIFF_FORMAT_NUMSTAT |
3257                                             DIFF_FORMAT_DIFFSTAT |
3258                                             DIFF_FORMAT_SHORTSTAT |
3259                                             DIFF_FORMAT_DIRSTAT |
3260                                             DIFF_FORMAT_SUMMARY |
3261                                             DIFF_FORMAT_PATCH);
3262
3263         /*
3264          * These cases always need recursive; we do not drop caller-supplied
3265          * recursive bits for other formats here.
3266          */
3267         if (options->output_format & (DIFF_FORMAT_PATCH |
3268                                       DIFF_FORMAT_NUMSTAT |
3269                                       DIFF_FORMAT_DIFFSTAT |
3270                                       DIFF_FORMAT_SHORTSTAT |
3271                                       DIFF_FORMAT_DIRSTAT |
3272                                       DIFF_FORMAT_SUMMARY |
3273                                       DIFF_FORMAT_CHECKDIFF))
3274                 DIFF_OPT_SET(options, RECURSIVE);
3275         /*
3276          * Also pickaxe would not work very well if you do not say recursive
3277          */
3278         if (options->pickaxe)
3279                 DIFF_OPT_SET(options, RECURSIVE);
3280         /*
3281          * When patches are generated, submodules diffed against the work tree
3282          * must be checked for dirtiness too so it can be shown in the output
3283          */
3284         if (options->output_format & DIFF_FORMAT_PATCH)
3285                 DIFF_OPT_SET(options, DIRTY_SUBMODULES);
3286
3287         if (options->detect_rename && options->rename_limit < 0)
3288                 options->rename_limit = diff_rename_limit_default;
3289         if (options->setup & DIFF_SETUP_USE_CACHE) {
3290                 if (!active_cache)
3291                         /* read-cache does not die even when it fails
3292                          * so it is safe for us to do this here.  Also
3293                          * it does not smudge active_cache or active_nr
3294                          * when it fails, so we do not have to worry about
3295                          * cleaning it up ourselves either.
3296                          */
3297                         read_cache();
3298         }
3299         if (options->abbrev <= 0 || 40 < options->abbrev)
3300                 options->abbrev = 40; /* full */
3301
3302         /*
3303          * It does not make sense to show the first hit we happened
3304          * to have found.  It does not make sense not to return with
3305          * exit code in such a case either.
3306          */
3307         if (DIFF_OPT_TST(options, QUICK)) {
3308                 options->output_format = DIFF_FORMAT_NO_OUTPUT;
3309                 DIFF_OPT_SET(options, EXIT_WITH_STATUS);
3310         }
3311 }
3312
3313 static int opt_arg(const char *arg, int arg_short, const char *arg_long, int *val)
3314 {
3315         char c, *eq;
3316         int len;
3317
3318         if (*arg != '-')
3319                 return 0;
3320         c = *++arg;
3321         if (!c)
3322                 return 0;
3323         if (c == arg_short) {
3324                 c = *++arg;
3325                 if (!c)
3326                         return 1;
3327                 if (val && isdigit(c)) {
3328                         char *end;
3329                         int n = strtoul(arg, &end, 10);
3330                         if (*end)
3331                                 return 0;
3332                         *val = n;
3333                         return 1;
3334                 }
3335                 return 0;
3336         }
3337         if (c != '-')
3338                 return 0;
3339         arg++;
3340         eq = strchr(arg, '=');
3341         if (eq)
3342                 len = eq - arg;
3343         else
3344                 len = strlen(arg);
3345         if (!len || strncmp(arg, arg_long, len))
3346                 return 0;
3347         if (eq) {
3348                 int n;
3349                 char *end;
3350                 if (!isdigit(*++eq))
3351                         return 0;
3352                 n = strtoul(eq, &end, 10);
3353                 if (*end)
3354                         return 0;
3355                 *val = n;
3356         }
3357         return 1;
3358 }
3359
3360 static int diff_scoreopt_parse(const char *opt);
3361
3362 static inline int short_opt(char opt, const char **argv,
3363                             const char **optarg)
3364 {
3365         const char *arg = argv[0];
3366         if (arg[0] != '-' || arg[1] != opt)
3367                 return 0;
3368         if (arg[2] != '\0') {
3369                 *optarg = arg + 2;
3370                 return 1;
3371         }
3372         if (!argv[1])
3373                 die("Option '%c' requires a value", opt);
3374         *optarg = argv[1];
3375         return 2;
3376 }
3377
3378 int parse_long_opt(const char *opt, const char **argv,
3379                    const char **optarg)
3380 {
3381         const char *arg = argv[0];
3382         if (arg[0] != '-' || arg[1] != '-')
3383                 return 0;
3384         arg += strlen("--");
3385         if (prefixcmp(arg, opt))
3386                 return 0;
3387         arg += strlen(opt);
3388         if (*arg == '=') { /* sticked form: --option=value */
3389                 *optarg = arg + 1;
3390                 return 1;
3391         }
3392         if (*arg != '\0')
3393                 return 0;
3394         /* separate form: --option value */
3395         if (!argv[1])
3396                 die("Option '--%s' requires a value", opt);
3397         *optarg = argv[1];
3398         return 2;
3399 }
3400
3401 static int stat_opt(struct diff_options *options, const char **av)
3402 {
3403         const char *arg = av[0];
3404         char *end;
3405         int width = options->stat_width;
3406         int name_width = options->stat_name_width;
3407         int graph_width = options->stat_graph_width;
3408         int count = options->stat_count;
3409         int argcount = 1;
3410
3411         arg += strlen("--stat");
3412         end = (char *)arg;
3413
3414         switch (*arg) {
3415         case '-':
3416                 if (!prefixcmp(arg, "-width")) {
3417                         arg += strlen("-width");
3418                         if (*arg == '=')
3419                                 width = strtoul(arg + 1, &end, 10);
3420                         else if (!*arg && !av[1])
3421                                 die("Option '--stat-width' requires a value");
3422                         else if (!*arg) {
3423                                 width = strtoul(av[1], &end, 10);
3424                                 argcount = 2;
3425                         }
3426                 } else if (!prefixcmp(arg, "-name-width")) {
3427                         arg += strlen("-name-width");
3428                         if (*arg == '=')
3429                                 name_width = strtoul(arg + 1, &end, 10);
3430                         else if (!*arg && !av[1])
3431                                 die("Option '--stat-name-width' requires a value");
3432                         else if (!*arg) {
3433                                 name_width = strtoul(av[1], &end, 10);
3434                                 argcount = 2;
3435                         }
3436                 } else if (!prefixcmp(arg, "-graph-width")) {
3437                         arg += strlen("-graph-width");
3438                         if (*arg == '=')
3439                                 graph_width = strtoul(arg + 1, &end, 10);
3440                         else if (!*arg && !av[1])
3441                                 die("Option '--stat-graph-width' requires a value");
3442                         else if (!*arg) {
3443                                 graph_width = strtoul(av[1], &end, 10);
3444                                 argcount = 2;
3445                         }
3446                 } else if (!prefixcmp(arg, "-count")) {
3447                         arg += strlen("-count");
3448                         if (*arg == '=')
3449                                 count = strtoul(arg + 1, &end, 10);
3450                         else if (!*arg && !av[1])
3451                                 die("Option '--stat-count' requires a value");
3452                         else if (!*arg) {
3453                                 count = strtoul(av[1], &end, 10);
3454                                 argcount = 2;
3455                         }
3456                 }
3457                 break;
3458         case '=':
3459                 width = strtoul(arg+1, &end, 10);
3460                 if (*end == ',')
3461                         name_width = strtoul(end+1, &end, 10);
3462                 if (*end == ',')
3463                         count = strtoul(end+1, &end, 10);
3464         }
3465
3466         /* Important! This checks all the error cases! */
3467         if (*end)
3468                 return 0;
3469         options->output_format |= DIFF_FORMAT_DIFFSTAT;
3470         options->stat_name_width = name_width;
3471         options->stat_graph_width = graph_width;
3472         options->stat_width = width;
3473         options->stat_count = count;
3474         return argcount;
3475 }
3476
3477 static int parse_dirstat_opt(struct diff_options *options, const char *params)
3478 {
3479         struct strbuf errmsg = STRBUF_INIT;
3480         if (parse_dirstat_params(options, params, &errmsg))
3481                 die(_("Failed to parse --dirstat/-X option parameter:\n%s"),
3482                     errmsg.buf);
3483         strbuf_release(&errmsg);
3484         /*
3485          * The caller knows a dirstat-related option is given from the command
3486          * line; allow it to say "return this_function();"
3487          */
3488         options->output_format |= DIFF_FORMAT_DIRSTAT;
3489         return 1;
3490 }
3491
3492 static int parse_submodule_opt(struct diff_options *options, const char *value)
3493 {
3494         if (parse_submodule_params(options, value))
3495                 die(_("Failed to parse --submodule option parameter: '%s'"),
3496                         value);
3497         return 1;
3498 }
3499
3500 int diff_opt_parse(struct diff_options *options, const char **av, int ac)
3501 {
3502         const char *arg = av[0];
3503         const char *optarg;
3504         int argcount;
3505
3506         /* Output format options */
3507         if (!strcmp(arg, "-p") || !strcmp(arg, "-u") || !strcmp(arg, "--patch"))
3508                 options->output_format |= DIFF_FORMAT_PATCH;
3509         else if (opt_arg(arg, 'U', "unified", &options->context))
3510                 options->output_format |= DIFF_FORMAT_PATCH;
3511         else if (!strcmp(arg, "--raw"))
3512                 options->output_format |= DIFF_FORMAT_RAW;
3513         else if (!strcmp(arg, "--patch-with-raw"))
3514                 options->output_format |= DIFF_FORMAT_PATCH | DIFF_FORMAT_RAW;
3515         else if (!strcmp(arg, "--numstat"))
3516                 options->output_format |= DIFF_FORMAT_NUMSTAT;
3517         else if (!strcmp(arg, "--shortstat"))
3518                 options->output_format |= DIFF_FORMAT_SHORTSTAT;
3519         else if (!strcmp(arg, "-X") || !strcmp(arg, "--dirstat"))
3520                 return parse_dirstat_opt(options, "");
3521         else if (!prefixcmp(arg, "-X"))
3522                 return parse_dirstat_opt(options, arg + 2);
3523         else if (!prefixcmp(arg, "--dirstat="))
3524                 return parse_dirstat_opt(options, arg + 10);
3525         else if (!strcmp(arg, "--cumulative"))
3526                 return parse_dirstat_opt(options, "cumulative");
3527         else if (!strcmp(arg, "--dirstat-by-file"))
3528                 return parse_dirstat_opt(options, "files");
3529         else if (!prefixcmp(arg, "--dirstat-by-file=")) {
3530                 parse_dirstat_opt(options, "files");
3531                 return parse_dirstat_opt(options, arg + 18);
3532         }
3533         else if (!strcmp(arg, "--check"))
3534                 options->output_format |= DIFF_FORMAT_CHECKDIFF;
3535         else if (!strcmp(arg, "--summary"))
3536                 options->output_format |= DIFF_FORMAT_SUMMARY;
3537         else if (!strcmp(arg, "--patch-with-stat"))
3538                 options->output_format |= DIFF_FORMAT_PATCH | DIFF_FORMAT_DIFFSTAT;
3539         else if (!strcmp(arg, "--name-only"))
3540                 options->output_format |= DIFF_FORMAT_NAME;
3541         else if (!strcmp(arg, "--name-status"))
3542                 options->output_format |= DIFF_FORMAT_NAME_STATUS;
3543         else if (!strcmp(arg, "-s"))
3544                 options->output_format |= DIFF_FORMAT_NO_OUTPUT;
3545         else if (!prefixcmp(arg, "--stat"))
3546                 /* --stat, --stat-width, --stat-name-width, or --stat-count */
3547                 return stat_opt(options, av);
3548
3549         /* renames options */
3550         else if (!prefixcmp(arg, "-B") || !prefixcmp(arg, "--break-rewrites=") ||
3551                  !strcmp(arg, "--break-rewrites")) {
3552                 if ((options->break_opt = diff_scoreopt_parse(arg)) == -1)
3553                         return error("invalid argument to -B: %s", arg+2);
3554         }
3555         else if (!prefixcmp(arg, "-M") || !prefixcmp(arg, "--find-renames=") ||
3556                  !strcmp(arg, "--find-renames")) {
3557                 if ((options->rename_score = diff_scoreopt_parse(arg)) == -1)
3558                         return error("invalid argument to -M: %s", arg+2);
3559                 options->detect_rename = DIFF_DETECT_RENAME;
3560         }
3561         else if (!strcmp(arg, "-D") || !strcmp(arg, "--irreversible-delete")) {
3562                 options->irreversible_delete = 1;
3563         }
3564         else if (!prefixcmp(arg, "-C") || !prefixcmp(arg, "--find-copies=") ||
3565                  !strcmp(arg, "--find-copies")) {
3566                 if (options->detect_rename == DIFF_DETECT_COPY)
3567                         DIFF_OPT_SET(options, FIND_COPIES_HARDER);
3568                 if ((options->rename_score = diff_scoreopt_parse(arg)) == -1)
3569                         return error("invalid argument to -C: %s", arg+2);
3570                 options->detect_rename = DIFF_DETECT_COPY;
3571         }
3572         else if (!strcmp(arg, "--no-renames"))
3573                 options->detect_rename = 0;
3574         else if (!strcmp(arg, "--rename-empty"))
3575                 DIFF_OPT_SET(options, RENAME_EMPTY);
3576         else if (!strcmp(arg, "--no-rename-empty"))
3577                 DIFF_OPT_CLR(options, RENAME_EMPTY);
3578         else if (!strcmp(arg, "--relative"))
3579                 DIFF_OPT_SET(options, RELATIVE_NAME);
3580         else if (!prefixcmp(arg, "--relative=")) {
3581                 DIFF_OPT_SET(options, RELATIVE_NAME);
3582                 options->prefix = arg + 11;
3583         }
3584
3585         /* xdiff options */
3586         else if (!strcmp(arg, "--minimal"))
3587                 DIFF_XDL_SET(options, NEED_MINIMAL);
3588         else if (!strcmp(arg, "--no-minimal"))
3589                 DIFF_XDL_CLR(options, NEED_MINIMAL);
3590         else if (!strcmp(arg, "-w") || !strcmp(arg, "--ignore-all-space"))
3591                 DIFF_XDL_SET(options, IGNORE_WHITESPACE);
3592         else if (!strcmp(arg, "-b") || !strcmp(arg, "--ignore-space-change"))
3593                 DIFF_XDL_SET(options, IGNORE_WHITESPACE_CHANGE);
3594         else if (!strcmp(arg, "--ignore-space-at-eol"))
3595                 DIFF_XDL_SET(options, IGNORE_WHITESPACE_AT_EOL);
3596         else if (!strcmp(arg, "--patience"))
3597                 options->xdl_opts = DIFF_WITH_ALG(options, PATIENCE_DIFF);
3598         else if (!strcmp(arg, "--histogram"))
3599                 options->xdl_opts = DIFF_WITH_ALG(options, HISTOGRAM_DIFF);
3600         else if ((argcount = parse_long_opt("diff-algorithm", av, &optarg))) {
3601                 long value = parse_algorithm_value(optarg);
3602                 if (value < 0)
3603                         return error("option diff-algorithm accepts \"myers\", "
3604                                      "\"minimal\", \"patience\" and \"histogram\"");
3605                 /* clear out previous settings */
3606                 DIFF_XDL_CLR(options, NEED_MINIMAL);
3607                 options->xdl_opts &= ~XDF_DIFF_ALGORITHM_MASK;
3608                 options->xdl_opts |= value;
3609                 return argcount;
3610         }
3611
3612         /* flags options */
3613         else if (!strcmp(arg, "--binary")) {
3614                 options->output_format |= DIFF_FORMAT_PATCH;
3615                 DIFF_OPT_SET(options, BINARY);
3616         }
3617         else if (!strcmp(arg, "--full-index"))
3618                 DIFF_OPT_SET(options, FULL_INDEX);
3619         else if (!strcmp(arg, "-a") || !strcmp(arg, "--text"))
3620                 DIFF_OPT_SET(options, TEXT);
3621         else if (!strcmp(arg, "-R"))
3622                 DIFF_OPT_SET(options, REVERSE_DIFF);
3623         else if (!strcmp(arg, "--find-copies-harder"))
3624                 DIFF_OPT_SET(options, FIND_COPIES_HARDER);
3625         else if (!strcmp(arg, "--follow"))
3626                 DIFF_OPT_SET(options, FOLLOW_RENAMES);
3627         else if (!strcmp(arg, "--no-follow"))
3628                 DIFF_OPT_CLR(options, FOLLOW_RENAMES);
3629         else if (!strcmp(arg, "--color"))
3630                 options->use_color = 1;
3631         else if (!prefixcmp(arg, "--color=")) {
3632                 int value = git_config_colorbool(NULL, arg+8);
3633                 if (value < 0)
3634                         return error("option `color' expects \"always\", \"auto\", or \"never\"");
3635                 options->use_color = value;
3636         }
3637         else if (!strcmp(arg, "--no-color"))
3638                 options->use_color = 0;
3639         else if (!strcmp(arg, "--color-words")) {
3640                 options->use_color = 1;
3641                 options->word_diff = DIFF_WORDS_COLOR;
3642         }
3643         else if (!prefixcmp(arg, "--color-words=")) {
3644                 options->use_color = 1;
3645                 options->word_diff = DIFF_WORDS_COLOR;
3646                 options->word_regex = arg + 14;
3647         }
3648         else if (!strcmp(arg, "--word-diff")) {
3649                 if (options->word_diff == DIFF_WORDS_NONE)
3650                         options->word_diff = DIFF_WORDS_PLAIN;
3651         }
3652         else if (!prefixcmp(arg, "--word-diff=")) {
3653                 const char *type = arg + 12;
3654                 if (!strcmp(type, "plain"))
3655                         options->word_diff = DIFF_WORDS_PLAIN;
3656                 else if (!strcmp(type, "color")) {
3657                         options->use_color = 1;
3658                         options->word_diff = DIFF_WORDS_COLOR;
3659                 }
3660                 else if (!strcmp(type, "porcelain"))
3661                         options->word_diff = DIFF_WORDS_PORCELAIN;
3662                 else if (!strcmp(type, "none"))
3663                         options->word_diff = DIFF_WORDS_NONE;
3664                 else
3665                         die("bad --word-diff argument: %s", type);
3666         }
3667         else if ((argcount = parse_long_opt("word-diff-regex", av, &optarg))) {
3668                 if (options->word_diff == DIFF_WORDS_NONE)
3669                         options->word_diff = DIFF_WORDS_PLAIN;
3670                 options->word_regex = optarg;
3671                 return argcount;
3672         }
3673         else if (!strcmp(arg, "--exit-code"))
3674                 DIFF_OPT_SET(options, EXIT_WITH_STATUS);
3675         else if (!strcmp(arg, "--quiet"))
3676                 DIFF_OPT_SET(options, QUICK);
3677         else if (!strcmp(arg, "--ext-diff"))
3678                 DIFF_OPT_SET(options, ALLOW_EXTERNAL);
3679         else if (!strcmp(arg, "--no-ext-diff"))
3680                 DIFF_OPT_CLR(options, ALLOW_EXTERNAL);
3681         else if (!strcmp(arg, "--textconv"))
3682                 DIFF_OPT_SET(options, ALLOW_TEXTCONV);
3683         else if (!strcmp(arg, "--no-textconv"))
3684                 DIFF_OPT_CLR(options, ALLOW_TEXTCONV);
3685         else if (!strcmp(arg, "--ignore-submodules")) {
3686                 DIFF_OPT_SET(options, OVERRIDE_SUBMODULE_CONFIG);
3687                 handle_ignore_submodules_arg(options, "all");
3688         } else if (!prefixcmp(arg, "--ignore-submodules=")) {
3689                 DIFF_OPT_SET(options, OVERRIDE_SUBMODULE_CONFIG);
3690                 handle_ignore_submodules_arg(options, arg + 20);
3691         } else if (!strcmp(arg, "--submodule"))
3692                 DIFF_OPT_SET(options, SUBMODULE_LOG);
3693         else if (!prefixcmp(arg, "--submodule="))
3694                 return parse_submodule_opt(options, arg + 12);
3695
3696         /* misc options */
3697         else if (!strcmp(arg, "-z"))
3698                 options->line_termination = 0;
3699         else if ((argcount = short_opt('l', av, &optarg))) {
3700                 options->rename_limit = strtoul(optarg, NULL, 10);
3701                 return argcount;
3702         }
3703         else if ((argcount = short_opt('S', av, &optarg))) {
3704                 options->pickaxe = optarg;
3705                 options->pickaxe_opts |= DIFF_PICKAXE_KIND_S;
3706                 return argcount;
3707         } else if ((argcount = short_opt('G', av, &optarg))) {
3708                 options->pickaxe = optarg;
3709                 options->pickaxe_opts |= DIFF_PICKAXE_KIND_G;
3710                 return argcount;
3711         }
3712         else if (!strcmp(arg, "--pickaxe-all"))
3713                 options->pickaxe_opts |= DIFF_PICKAXE_ALL;
3714         else if (!strcmp(arg, "--pickaxe-regex"))
3715                 options->pickaxe_opts |= DIFF_PICKAXE_REGEX;
3716         else if ((argcount = short_opt('O', av, &optarg))) {
3717                 options->orderfile = optarg;
3718                 return argcount;
3719         }
3720         else if ((argcount = parse_long_opt("diff-filter", av, &optarg))) {
3721                 options->filter = optarg;
3722                 return argcount;
3723         }
3724         else if (!strcmp(arg, "--abbrev"))
3725                 options->abbrev = DEFAULT_ABBREV;
3726         else if (!prefixcmp(arg, "--abbrev=")) {
3727                 options->abbrev = strtoul(arg + 9, NULL, 10);
3728                 if (options->abbrev < MINIMUM_ABBREV)
3729                         options->abbrev = MINIMUM_ABBREV;
3730                 else if (40 < options->abbrev)
3731                         options->abbrev = 40;
3732         }
3733         else if ((argcount = parse_long_opt("src-prefix", av, &optarg))) {
3734                 options->a_prefix = optarg;
3735                 return argcount;
3736         }
3737         else if ((argcount = parse_long_opt("dst-prefix", av, &optarg))) {
3738                 options->b_prefix = optarg;
3739                 return argcount;
3740         }
3741         else if (!strcmp(arg, "--no-prefix"))
3742                 options->a_prefix = options->b_prefix = "";
3743         else if (opt_arg(arg, '\0', "inter-hunk-context",
3744                          &options->interhunkcontext))
3745                 ;
3746         else if (!strcmp(arg, "-W"))
3747                 DIFF_OPT_SET(options, FUNCCONTEXT);
3748         else if (!strcmp(arg, "--function-context"))
3749                 DIFF_OPT_SET(options, FUNCCONTEXT);
3750         else if (!strcmp(arg, "--no-function-context"))
3751                 DIFF_OPT_CLR(options, FUNCCONTEXT);
3752         else if ((argcount = parse_long_opt("output", av, &optarg))) {
3753                 options->file = fopen(optarg, "w");
3754                 if (!options->file)
3755                         die_errno("Could not open '%s'", optarg);
3756                 options->close_file = 1;
3757                 return argcount;
3758         } else
3759                 return 0;
3760         return 1;
3761 }
3762
3763 int parse_rename_score(const char **cp_p)
3764 {
3765         unsigned long num, scale;
3766         int ch, dot;
3767         const char *cp = *cp_p;
3768
3769         num = 0;
3770         scale = 1;
3771         dot = 0;
3772         for (;;) {
3773                 ch = *cp;
3774                 if ( !dot && ch == '.' ) {
3775                         scale = 1;
3776                         dot = 1;
3777                 } else if ( ch == '%' ) {
3778                         scale = dot ? scale*100 : 100;
3779                         cp++;   /* % is always at the end */
3780                         break;
3781                 } else if ( ch >= '0' && ch <= '9' ) {
3782                         if ( scale < 100000 ) {
3783                                 scale *= 10;
3784                                 num = (num*10) + (ch-'0');
3785                         }
3786                 } else {
3787                         break;
3788                 }
3789                 cp++;
3790         }
3791         *cp_p = cp;
3792
3793         /* user says num divided by scale and we say internally that
3794          * is MAX_SCORE * num / scale.
3795          */
3796         return (int)((num >= scale) ? MAX_SCORE : (MAX_SCORE * num / scale));
3797 }
3798
3799 static int diff_scoreopt_parse(const char *opt)
3800 {
3801         int opt1, opt2, cmd;
3802
3803         if (*opt++ != '-')
3804                 return -1;
3805         cmd = *opt++;
3806         if (cmd == '-') {
3807                 /* convert the long-form arguments into short-form versions */
3808                 if (!prefixcmp(opt, "break-rewrites")) {
3809                         opt += strlen("break-rewrites");
3810                         if (*opt == 0 || *opt++ == '=')
3811                                 cmd = 'B';
3812                 } else if (!prefixcmp(opt, "find-copies")) {
3813                         opt += strlen("find-copies");
3814                         if (*opt == 0 || *opt++ == '=')
3815                                 cmd = 'C';
3816                 } else if (!prefixcmp(opt, "find-renames")) {
3817                         opt += strlen("find-renames");
3818                         if (*opt == 0 || *opt++ == '=')
3819                                 cmd = 'M';
3820                 }
3821         }
3822         if (cmd != 'M' && cmd != 'C' && cmd != 'B')
3823                 return -1; /* that is not a -M, -C nor -B option */
3824
3825         opt1 = parse_rename_score(&opt);
3826         if (cmd != 'B')
3827                 opt2 = 0;
3828         else {
3829                 if (*opt == 0)
3830                         opt2 = 0;
3831                 else if (*opt != '/')
3832                         return -1; /* we expect -B80/99 or -B80 */
3833                 else {
3834                         opt++;
3835                         opt2 = parse_rename_score(&opt);
3836                 }
3837         }
3838         if (*opt != 0)
3839                 return -1;
3840         return opt1 | (opt2 << 16);
3841 }
3842
3843 struct diff_queue_struct diff_queued_diff;
3844
3845 void diff_q(struct diff_queue_struct *queue, struct diff_filepair *dp)
3846 {
3847         if (queue->alloc <= queue->nr) {
3848                 queue->alloc = alloc_nr(queue->alloc);
3849                 queue->queue = xrealloc(queue->queue,
3850                                         sizeof(dp) * queue->alloc);
3851         }
3852         queue->queue[queue->nr++] = dp;
3853 }
3854
3855 struct diff_filepair *diff_queue(struct diff_queue_struct *queue,
3856                                  struct diff_filespec *one,
3857                                  struct diff_filespec *two)
3858 {
3859         struct diff_filepair *dp = xcalloc(1, sizeof(*dp));
3860         dp->one = one;
3861         dp->two = two;
3862         if (queue)
3863                 diff_q(queue, dp);
3864         return dp;
3865 }
3866
3867 void diff_free_filepair(struct diff_filepair *p)
3868 {
3869         free_filespec(p->one);
3870         free_filespec(p->two);
3871         free(p);
3872 }
3873
3874 /* This is different from find_unique_abbrev() in that
3875  * it stuffs the result with dots for alignment.
3876  */
3877 const char *diff_unique_abbrev(const unsigned char *sha1, int len)
3878 {
3879         int abblen;
3880         const char *abbrev;
3881         if (len == 40)
3882                 return sha1_to_hex(sha1);
3883
3884         abbrev = find_unique_abbrev(sha1, len);
3885         abblen = strlen(abbrev);
3886         if (abblen < 37) {
3887                 static char hex[41];
3888                 if (len < abblen && abblen <= len + 2)
3889                         sprintf(hex, "%s%.*s", abbrev, len+3-abblen, "..");
3890                 else
3891                         sprintf(hex, "%s...", abbrev);
3892                 return hex;
3893         }
3894         return sha1_to_hex(sha1);
3895 }
3896
3897 static void diff_flush_raw(struct diff_filepair *p, struct diff_options *opt)
3898 {
3899         int line_termination = opt->line_termination;
3900         int inter_name_termination = line_termination ? '\t' : '\0';
3901
3902         fprintf(opt->file, "%s", diff_line_prefix(opt));
3903         if (!(opt->output_format & DIFF_FORMAT_NAME_STATUS)) {
3904                 fprintf(opt->file, ":%06o %06o %s ", p->one->mode, p->two->mode,
3905                         diff_unique_abbrev(p->one->sha1, opt->abbrev));
3906                 fprintf(opt->file, "%s ", diff_unique_abbrev(p->two->sha1, opt->abbrev));
3907         }
3908         if (p->score) {
3909                 fprintf(opt->file, "%c%03d%c", p->status, similarity_index(p),
3910                         inter_name_termination);
3911         } else {
3912                 fprintf(opt->file, "%c%c", p->status, inter_name_termination);
3913         }
3914
3915         if (p->status == DIFF_STATUS_COPIED ||
3916             p->status == DIFF_STATUS_RENAMED) {
3917                 const char *name_a, *name_b;
3918                 name_a = p->one->path;
3919                 name_b = p->two->path;
3920                 strip_prefix(opt->prefix_length, &name_a, &name_b);
3921                 write_name_quoted(name_a, opt->file, inter_name_termination);
3922                 write_name_quoted(name_b, opt->file, line_termination);
3923         } else {
3924                 const char *name_a, *name_b;
3925                 name_a = p->one->mode ? p->one->path : p->two->path;
3926                 name_b = NULL;
3927                 strip_prefix(opt->prefix_length, &name_a, &name_b);
3928                 write_name_quoted(name_a, opt->file, line_termination);
3929         }
3930 }
3931
3932 int diff_unmodified_pair(struct diff_filepair *p)
3933 {
3934         /* This function is written stricter than necessary to support
3935          * the currently implemented transformers, but the idea is to
3936          * let transformers to produce diff_filepairs any way they want,
3937          * and filter and clean them up here before producing the output.
3938          */
3939         struct diff_filespec *one = p->one, *two = p->two;
3940
3941         if (DIFF_PAIR_UNMERGED(p))
3942                 return 0; /* unmerged is interesting */
3943
3944         /* deletion, addition, mode or type change
3945          * and rename are all interesting.
3946          */
3947         if (DIFF_FILE_VALID(one) != DIFF_FILE_VALID(two) ||
3948             DIFF_PAIR_MODE_CHANGED(p) ||
3949             strcmp(one->path, two->path))
3950                 return 0;
3951
3952         /* both are valid and point at the same path.  that is, we are
3953          * dealing with a change.
3954          */
3955         if (one->sha1_valid && two->sha1_valid &&
3956             !hashcmp(one->sha1, two->sha1) &&
3957             !one->dirty_submodule && !two->dirty_submodule)
3958                 return 1; /* no change */
3959         if (!one->sha1_valid && !two->sha1_valid)
3960                 return 1; /* both look at the same file on the filesystem. */
3961         return 0;
3962 }
3963
3964 static void diff_flush_patch(struct diff_filepair *p, struct diff_options *o)
3965 {
3966         if (diff_unmodified_pair(p))
3967                 return;
3968
3969         if ((DIFF_FILE_VALID(p->one) && S_ISDIR(p->one->mode)) ||
3970             (DIFF_FILE_VALID(p->two) && S_ISDIR(p->two->mode)))
3971                 return; /* no tree diffs in patch format */
3972
3973         run_diff(p, o);
3974 }
3975
3976 static void diff_flush_stat(struct diff_filepair *p, struct diff_options *o,
3977                             struct diffstat_t *diffstat)
3978 {
3979         if (diff_unmodified_pair(p))
3980                 return;
3981
3982         if ((DIFF_FILE_VALID(p->one) && S_ISDIR(p->one->mode)) ||
3983             (DIFF_FILE_VALID(p->two) && S_ISDIR(p->two->mode)))
3984                 return; /* no useful stat for tree diffs */
3985
3986         run_diffstat(p, o, diffstat);
3987 }
3988
3989 static void diff_flush_checkdiff(struct diff_filepair *p,
3990                 struct diff_options *o)
3991 {
3992         if (diff_unmodified_pair(p))
3993                 return;
3994
3995         if ((DIFF_FILE_VALID(p->one) && S_ISDIR(p->one->mode)) ||
3996             (DIFF_FILE_VALID(p->two) && S_ISDIR(p->two->mode)))
3997                 return; /* nothing to check in tree diffs */
3998
3999         run_checkdiff(p, o);
4000 }
4001
4002 int diff_queue_is_empty(void)
4003 {
4004         struct diff_queue_struct *q = &diff_queued_diff;
4005         int i;
4006         for (i = 0; i < q->nr; i++)
4007                 if (!diff_unmodified_pair(q->queue[i]))
4008                         return 0;
4009         return 1;
4010 }
4011
4012 #if DIFF_DEBUG
4013 void diff_debug_filespec(struct diff_filespec *s, int x, const char *one)
4014 {
4015         fprintf(stderr, "queue[%d] %s (%s) %s %06o %s\n",
4016                 x, one ? one : "",
4017                 s->path,
4018                 DIFF_FILE_VALID(s) ? "valid" : "invalid",
4019                 s->mode,
4020                 s->sha1_valid ? sha1_to_hex(s->sha1) : "");
4021         fprintf(stderr, "queue[%d] %s size %lu flags %d\n",
4022                 x, one ? one : "",
4023                 s->size, s->xfrm_flags);
4024 }
4025
4026 void diff_debug_filepair(const struct diff_filepair *p, int i)
4027 {
4028         diff_debug_filespec(p->one, i, "one");
4029         diff_debug_filespec(p->two, i, "two");
4030         fprintf(stderr, "score %d, status %c rename_used %d broken %d\n",
4031                 p->score, p->status ? p->status : '?',
4032                 p->one->rename_used, p->broken_pair);
4033 }
4034
4035 void diff_debug_queue(const char *msg, struct diff_queue_struct *q)
4036 {
4037         int i;
4038         if (msg)
4039                 fprintf(stderr, "%s\n", msg);
4040         fprintf(stderr, "q->nr = %d\n", q->nr);
4041         for (i = 0; i < q->nr; i++) {
4042                 struct diff_filepair *p = q->queue[i];
4043                 diff_debug_filepair(p, i);
4044         }
4045 }
4046 #endif
4047
4048 static void diff_resolve_rename_copy(void)
4049 {
4050         int i;
4051         struct diff_filepair *p;
4052         struct diff_queue_struct *q = &diff_queued_diff;
4053
4054         diff_debug_queue("resolve-rename-copy", q);
4055
4056         for (i = 0; i < q->nr; i++) {
4057                 p = q->queue[i];
4058                 p->status = 0; /* undecided */
4059                 if (DIFF_PAIR_UNMERGED(p))
4060                         p->status = DIFF_STATUS_UNMERGED;
4061                 else if (!DIFF_FILE_VALID(p->one))
4062                         p->status = DIFF_STATUS_ADDED;
4063                 else if (!DIFF_FILE_VALID(p->two))
4064                         p->status = DIFF_STATUS_DELETED;
4065                 else if (DIFF_PAIR_TYPE_CHANGED(p))
4066                         p->status = DIFF_STATUS_TYPE_CHANGED;
4067
4068                 /* from this point on, we are dealing with a pair
4069                  * whose both sides are valid and of the same type, i.e.
4070                  * either in-place edit or rename/copy edit.
4071                  */
4072                 else if (DIFF_PAIR_RENAME(p)) {
4073                         /*
4074                          * A rename might have re-connected a broken
4075                          * pair up, causing the pathnames to be the
4076                          * same again. If so, that's not a rename at
4077                          * all, just a modification..
4078                          *
4079                          * Otherwise, see if this source was used for
4080                          * multiple renames, in which case we decrement
4081                          * the count, and call it a copy.
4082                          */
4083                         if (!strcmp(p->one->path, p->two->path))
4084                                 p->status = DIFF_STATUS_MODIFIED;
4085                         else if (--p->one->rename_used > 0)
4086                                 p->status = DIFF_STATUS_COPIED;
4087                         else
4088                                 p->status = DIFF_STATUS_RENAMED;
4089                 }
4090                 else if (hashcmp(p->one->sha1, p->two->sha1) ||
4091                          p->one->mode != p->two->mode ||
4092                          p->one->dirty_submodule ||
4093                          p->two->dirty_submodule ||
4094                          is_null_sha1(p->one->sha1))
4095                         p->status = DIFF_STATUS_MODIFIED;
4096                 else {
4097                         /* This is a "no-change" entry and should not
4098                          * happen anymore, but prepare for broken callers.
4099                          */
4100                         error("feeding unmodified %s to diffcore",
4101                               p->one->path);
4102                         p->status = DIFF_STATUS_UNKNOWN;
4103                 }
4104         }
4105         diff_debug_queue("resolve-rename-copy done", q);
4106 }
4107
4108 static int check_pair_status(struct diff_filepair *p)
4109 {
4110         switch (p->status) {
4111         case DIFF_STATUS_UNKNOWN:
4112                 return 0;
4113         case 0:
4114                 die("internal error in diff-resolve-rename-copy");
4115         default:
4116                 return 1;
4117         }
4118 }
4119
4120 static void flush_one_pair(struct diff_filepair *p, struct diff_options *opt)
4121 {
4122         int fmt = opt->output_format;
4123
4124         if (fmt & DIFF_FORMAT_CHECKDIFF)
4125                 diff_flush_checkdiff(p, opt);
4126         else if (fmt & (DIFF_FORMAT_RAW | DIFF_FORMAT_NAME_STATUS))
4127                 diff_flush_raw(p, opt);
4128         else if (fmt & DIFF_FORMAT_NAME) {
4129                 const char *name_a, *name_b;
4130                 name_a = p->two->path;
4131                 name_b = NULL;
4132                 strip_prefix(opt->prefix_length, &name_a, &name_b);
4133                 write_name_quoted(name_a, opt->file, opt->line_termination);
4134         }
4135 }
4136
4137 static void show_file_mode_name(FILE *file, const char *newdelete, struct diff_filespec *fs)
4138 {
4139         if (fs->mode)
4140                 fprintf(file, " %s mode %06o ", newdelete, fs->mode);
4141         else
4142                 fprintf(file, " %s ", newdelete);
4143         write_name_quoted(fs->path, file, '\n');
4144 }
4145
4146
4147 static void show_mode_change(FILE *file, struct diff_filepair *p, int show_name,
4148                 const char *line_prefix)
4149 {
4150         if (p->one->mode && p->two->mode && p->one->mode != p->two->mode) {
4151                 fprintf(file, "%s mode change %06o => %06o%c", line_prefix, p->one->mode,
4152                         p->two->mode, show_name ? ' ' : '\n');
4153                 if (show_name) {
4154                         write_name_quoted(p->two->path, file, '\n');
4155                 }
4156         }
4157 }
4158
4159 static void show_rename_copy(FILE *file, const char *renamecopy, struct diff_filepair *p,
4160                         const char *line_prefix)
4161 {
4162         char *names = pprint_rename(p->one->path, p->two->path);
4163
4164         fprintf(file, " %s %s (%d%%)\n", renamecopy, names, similarity_index(p));
4165         free(names);
4166         show_mode_change(file, p, 0, line_prefix);
4167 }
4168
4169 static void diff_summary(struct diff_options *opt, struct diff_filepair *p)
4170 {
4171         FILE *file = opt->file;
4172         const char *line_prefix = diff_line_prefix(opt);
4173
4174         switch(p->status) {
4175         case DIFF_STATUS_DELETED:
4176                 fputs(line_prefix, file);
4177                 show_file_mode_name(file, "delete", p->one);
4178                 break;
4179         case DIFF_STATUS_ADDED:
4180                 fputs(line_prefix, file);
4181                 show_file_mode_name(file, "create", p->two);
4182                 break;
4183         case DIFF_STATUS_COPIED:
4184                 fputs(line_prefix, file);
4185                 show_rename_copy(file, "copy", p, line_prefix);
4186                 break;
4187         case DIFF_STATUS_RENAMED:
4188                 fputs(line_prefix, file);
4189                 show_rename_copy(file, "rename", p, line_prefix);
4190                 break;
4191         default:
4192                 if (p->score) {
4193                         fprintf(file, "%s rewrite ", line_prefix);
4194                         write_name_quoted(p->two->path, file, ' ');
4195                         fprintf(file, "(%d%%)\n", similarity_index(p));
4196                 }
4197                 show_mode_change(file, p, !p->score, line_prefix);
4198                 break;
4199         }
4200 }
4201
4202 struct patch_id_t {
4203         git_SHA_CTX *ctx;
4204         int patchlen;
4205 };
4206
4207 static int remove_space(char *line, int len)
4208 {
4209         int i;
4210         char *dst = line;
4211         unsigned char c;
4212
4213         for (i = 0; i < len; i++)
4214                 if (!isspace((c = line[i])))
4215                         *dst++ = c;
4216
4217         return dst - line;
4218 }
4219
4220 static void patch_id_consume(void *priv, char *line, unsigned long len)
4221 {
4222         struct patch_id_t *data = priv;
4223         int new_len;
4224
4225         /* Ignore line numbers when computing the SHA1 of the patch */
4226         if (!prefixcmp(line, "@@ -"))
4227                 return;
4228
4229         new_len = remove_space(line, len);
4230
4231         git_SHA1_Update(data->ctx, line, new_len);
4232         data->patchlen += new_len;
4233 }
4234
4235 /* returns 0 upon success, and writes result into sha1 */
4236 static int diff_get_patch_id(struct diff_options *options, unsigned char *sha1)
4237 {
4238         struct diff_queue_struct *q = &diff_queued_diff;
4239         int i;
4240         git_SHA_CTX ctx;
4241         struct patch_id_t data;
4242         char buffer[PATH_MAX * 4 + 20];
4243
4244         git_SHA1_Init(&ctx);
4245         memset(&data, 0, sizeof(struct patch_id_t));
4246         data.ctx = &ctx;
4247
4248         for (i = 0; i < q->nr; i++) {
4249                 xpparam_t xpp;
4250                 xdemitconf_t xecfg;
4251                 mmfile_t mf1, mf2;
4252                 struct diff_filepair *p = q->queue[i];
4253                 int len1, len2;
4254
4255                 memset(&xpp, 0, sizeof(xpp));
4256                 memset(&xecfg, 0, sizeof(xecfg));
4257                 if (p->status == 0)
4258                         return error("internal diff status error");
4259                 if (p->status == DIFF_STATUS_UNKNOWN)
4260                         continue;
4261                 if (diff_unmodified_pair(p))
4262                         continue;
4263                 if ((DIFF_FILE_VALID(p->one) && S_ISDIR(p->one->mode)) ||
4264                     (DIFF_FILE_VALID(p->two) && S_ISDIR(p->two->mode)))
4265                         continue;
4266                 if (DIFF_PAIR_UNMERGED(p))
4267                         continue;
4268
4269                 diff_fill_sha1_info(p->one);
4270                 diff_fill_sha1_info(p->two);
4271                 if (fill_mmfile(&mf1, p->one) < 0 ||
4272                                 fill_mmfile(&mf2, p->two) < 0)
4273                         return error("unable to read files to diff");
4274
4275                 len1 = remove_space(p->one->path, strlen(p->one->path));
4276                 len2 = remove_space(p->two->path, strlen(p->two->path));
4277                 if (p->one->mode == 0)
4278                         len1 = snprintf(buffer, sizeof(buffer),
4279                                         "diff--gita/%.*sb/%.*s"
4280                                         "newfilemode%06o"
4281                                         "---/dev/null"
4282                                         "+++b/%.*s",
4283                                         len1, p->one->path,
4284                                         len2, p->two->path,
4285                                         p->two->mode,
4286                                         len2, p->two->path);
4287                 else if (p->two->mode == 0)
4288                         len1 = snprintf(buffer, sizeof(buffer),
4289                                         "diff--gita/%.*sb/%.*s"
4290                                         "deletedfilemode%06o"
4291                                         "---a/%.*s"
4292                                         "+++/dev/null",
4293                                         len1, p->one->path,
4294                                         len2, p->two->path,
4295                                         p->one->mode,
4296                                         len1, p->one->path);
4297                 else
4298                         len1 = snprintf(buffer, sizeof(buffer),
4299                                         "diff--gita/%.*sb/%.*s"
4300                                         "---a/%.*s"
4301                                         "+++b/%.*s",
4302                                         len1, p->one->path,
4303                                         len2, p->two->path,
4304                                         len1, p->one->path,
4305                                         len2, p->two->path);
4306                 git_SHA1_Update(&ctx, buffer, len1);
4307
4308                 if (diff_filespec_is_binary(p->one) ||
4309                     diff_filespec_is_binary(p->two)) {
4310                         git_SHA1_Update(&ctx, sha1_to_hex(p->one->sha1), 40);
4311                         git_SHA1_Update(&ctx, sha1_to_hex(p->two->sha1), 40);
4312                         continue;
4313                 }
4314
4315                 xpp.flags = 0;
4316                 xecfg.ctxlen = 3;
4317                 xecfg.flags = 0;
4318                 xdi_diff_outf(&mf1, &mf2, patch_id_consume, &data,
4319                               &xpp, &xecfg);
4320         }
4321
4322         git_SHA1_Final(sha1, &ctx);
4323         return 0;
4324 }
4325
4326 int diff_flush_patch_id(struct diff_options *options, unsigned char *sha1)
4327 {
4328         struct diff_queue_struct *q = &diff_queued_diff;
4329         int i;
4330         int result = diff_get_patch_id(options, sha1);
4331
4332         for (i = 0; i < q->nr; i++)
4333                 diff_free_filepair(q->queue[i]);
4334
4335         free(q->queue);
4336         DIFF_QUEUE_CLEAR(q);
4337
4338         return result;
4339 }
4340
4341 static int is_summary_empty(const struct diff_queue_struct *q)
4342 {
4343         int i;
4344
4345         for (i = 0; i < q->nr; i++) {
4346                 const struct diff_filepair *p = q->queue[i];
4347
4348                 switch (p->status) {
4349                 case DIFF_STATUS_DELETED:
4350                 case DIFF_STATUS_ADDED:
4351                 case DIFF_STATUS_COPIED:
4352                 case DIFF_STATUS_RENAMED:
4353                         return 0;
4354                 default:
4355                         if (p->score)
4356                                 return 0;
4357                         if (p->one->mode && p->two->mode &&
4358                             p->one->mode != p->two->mode)
4359                                 return 0;
4360                         break;
4361                 }
4362         }
4363         return 1;
4364 }
4365
4366 static const char rename_limit_warning[] =
4367 "inexact rename detection was skipped due to too many files.";
4368
4369 static const char degrade_cc_to_c_warning[] =
4370 "only found copies from modified paths due to too many files.";
4371
4372 static const char rename_limit_advice[] =
4373 "you may want to set your %s variable to at least "
4374 "%d and retry the command.";
4375
4376 void diff_warn_rename_limit(const char *varname, int needed, int degraded_cc)
4377 {
4378         if (degraded_cc)
4379                 warning(degrade_cc_to_c_warning);
4380         else if (needed)
4381                 warning(rename_limit_warning);
4382         else
4383                 return;
4384         if (0 < needed && needed < 32767)
4385                 warning(rename_limit_advice, varname, needed);
4386 }
4387
4388 void diff_flush(struct diff_options *options)
4389 {
4390         struct diff_queue_struct *q = &diff_queued_diff;
4391         int i, output_format = options->output_format;
4392         int separator = 0;
4393         int dirstat_by_line = 0;
4394
4395         /*
4396          * Order: raw, stat, summary, patch
4397          * or:    name/name-status/checkdiff (other bits clear)
4398          */
4399         if (!q->nr)
4400                 goto free_queue;
4401
4402         if (output_format & (DIFF_FORMAT_RAW |
4403                              DIFF_FORMAT_NAME |
4404                              DIFF_FORMAT_NAME_STATUS |
4405                              DIFF_FORMAT_CHECKDIFF)) {
4406                 for (i = 0; i < q->nr; i++) {
4407                         struct diff_filepair *p = q->queue[i];
4408                         if (check_pair_status(p))
4409                                 flush_one_pair(p, options);
4410                 }
4411                 separator++;
4412         }
4413
4414         if (output_format & DIFF_FORMAT_DIRSTAT && DIFF_OPT_TST(options, DIRSTAT_BY_LINE))
4415                 dirstat_by_line = 1;
4416
4417         if (output_format & (DIFF_FORMAT_DIFFSTAT|DIFF_FORMAT_SHORTSTAT|DIFF_FORMAT_NUMSTAT) ||
4418             dirstat_by_line) {
4419                 struct diffstat_t diffstat;
4420
4421                 memset(&diffstat, 0, sizeof(struct diffstat_t));
4422                 for (i = 0; i < q->nr; i++) {
4423                         struct diff_filepair *p = q->queue[i];
4424                         if (check_pair_status(p))
4425                                 diff_flush_stat(p, options, &diffstat);
4426                 }
4427                 if (output_format & DIFF_FORMAT_NUMSTAT)
4428                         show_numstat(&diffstat, options);
4429                 if (output_format & DIFF_FORMAT_DIFFSTAT)
4430                         show_stats(&diffstat, options);
4431                 if (output_format & DIFF_FORMAT_SHORTSTAT)
4432                         show_shortstats(&diffstat, options);
4433                 if (output_format & DIFF_FORMAT_DIRSTAT)
4434                         show_dirstat_by_line(&diffstat, options);
4435                 free_diffstat_info(&diffstat);
4436                 separator++;
4437         }
4438         if ((output_format & DIFF_FORMAT_DIRSTAT) && !dirstat_by_line)
4439                 show_dirstat(options);
4440
4441         if (output_format & DIFF_FORMAT_SUMMARY && !is_summary_empty(q)) {
4442                 for (i = 0; i < q->nr; i++) {
4443                         diff_summary(options, q->queue[i]);
4444                 }
4445                 separator++;
4446         }
4447
4448         if (output_format & DIFF_FORMAT_NO_OUTPUT &&
4449             DIFF_OPT_TST(options, EXIT_WITH_STATUS) &&
4450             DIFF_OPT_TST(options, DIFF_FROM_CONTENTS)) {
4451                 /*
4452                  * run diff_flush_patch for the exit status. setting
4453                  * options->file to /dev/null should be safe, becaue we
4454                  * aren't supposed to produce any output anyway.
4455                  */
4456                 if (options->close_file)
4457                         fclose(options->file);
4458                 options->file = fopen("/dev/null", "w");
4459                 if (!options->file)
4460                         die_errno("Could not open /dev/null");
4461                 options->close_file = 1;
4462                 for (i = 0; i < q->nr; i++) {
4463                         struct diff_filepair *p = q->queue[i];
4464                         if (check_pair_status(p))
4465                                 diff_flush_patch(p, options);
4466                         if (options->found_changes)
4467                                 break;
4468                 }
4469         }
4470
4471         if (output_format & DIFF_FORMAT_PATCH) {
4472                 if (separator) {
4473                         fprintf(options->file, "%s%c",
4474                                 diff_line_prefix(options),
4475                                 options->line_termination);
4476                         if (options->stat_sep) {
4477                                 /* attach patch instead of inline */
4478                                 fputs(options->stat_sep, options->file);
4479                         }
4480                 }
4481
4482                 for (i = 0; i < q->nr; i++) {
4483                         struct diff_filepair *p = q->queue[i];
4484                         if (check_pair_status(p))
4485                                 diff_flush_patch(p, options);
4486                 }
4487         }
4488
4489         if (output_format & DIFF_FORMAT_CALLBACK)
4490                 options->format_callback(q, options, options->format_callback_data);
4491
4492         for (i = 0; i < q->nr; i++)
4493                 diff_free_filepair(q->queue[i]);
4494 free_queue:
4495         free(q->queue);
4496         DIFF_QUEUE_CLEAR(q);
4497         if (options->close_file)
4498                 fclose(options->file);
4499
4500         /*
4501          * Report the content-level differences with HAS_CHANGES;
4502          * diff_addremove/diff_change does not set the bit when
4503          * DIFF_FROM_CONTENTS is in effect (e.g. with -w).
4504          */
4505         if (DIFF_OPT_TST(options, DIFF_FROM_CONTENTS)) {
4506                 if (options->found_changes)
4507                         DIFF_OPT_SET(options, HAS_CHANGES);
4508                 else
4509                         DIFF_OPT_CLR(options, HAS_CHANGES);
4510         }
4511 }
4512
4513 static void diffcore_apply_filter(const char *filter)
4514 {
4515         int i;
4516         struct diff_queue_struct *q = &diff_queued_diff;
4517         struct diff_queue_struct outq;
4518         DIFF_QUEUE_CLEAR(&outq);
4519
4520         if (!filter)
4521                 return;
4522
4523         if (strchr(filter, DIFF_STATUS_FILTER_AON)) {
4524                 int found;
4525                 for (i = found = 0; !found && i < q->nr; i++) {
4526                         struct diff_filepair *p = q->queue[i];
4527                         if (((p->status == DIFF_STATUS_MODIFIED) &&
4528                              ((p->score &&
4529                                strchr(filter, DIFF_STATUS_FILTER_BROKEN)) ||
4530                               (!p->score &&
4531                                strchr(filter, DIFF_STATUS_MODIFIED)))) ||
4532                             ((p->status != DIFF_STATUS_MODIFIED) &&
4533                              strchr(filter, p->status)))
4534                                 found++;
4535                 }
4536                 if (found)
4537                         return;
4538
4539                 /* otherwise we will clear the whole queue
4540                  * by copying the empty outq at the end of this
4541                  * function, but first clear the current entries
4542                  * in the queue.
4543                  */
4544                 for (i = 0; i < q->nr; i++)
4545                         diff_free_filepair(q->queue[i]);
4546         }
4547         else {
4548                 /* Only the matching ones */
4549                 for (i = 0; i < q->nr; i++) {
4550                         struct diff_filepair *p = q->queue[i];
4551
4552                         if (((p->status == DIFF_STATUS_MODIFIED) &&
4553                              ((p->score &&
4554                                strchr(filter, DIFF_STATUS_FILTER_BROKEN)) ||
4555                               (!p->score &&
4556                                strchr(filter, DIFF_STATUS_MODIFIED)))) ||
4557                             ((p->status != DIFF_STATUS_MODIFIED) &&
4558                              strchr(filter, p->status)))
4559                                 diff_q(&outq, p);
4560                         else
4561                                 diff_free_filepair(p);
4562                 }
4563         }
4564         free(q->queue);
4565         *q = outq;
4566 }
4567
4568 /* Check whether two filespecs with the same mode and size are identical */
4569 static int diff_filespec_is_identical(struct diff_filespec *one,
4570                                       struct diff_filespec *two)
4571 {
4572         if (S_ISGITLINK(one->mode))
4573                 return 0;
4574         if (diff_populate_filespec(one, 0))
4575                 return 0;
4576         if (diff_populate_filespec(two, 0))
4577                 return 0;
4578         return !memcmp(one->data, two->data, one->size);
4579 }
4580
4581 static void diffcore_skip_stat_unmatch(struct diff_options *diffopt)
4582 {
4583         int i;
4584         struct diff_queue_struct *q = &diff_queued_diff;
4585         struct diff_queue_struct outq;
4586         DIFF_QUEUE_CLEAR(&outq);
4587
4588         for (i = 0; i < q->nr; i++) {
4589                 struct diff_filepair *p = q->queue[i];
4590
4591                 /*
4592                  * 1. Entries that come from stat info dirtiness
4593                  *    always have both sides (iow, not create/delete),
4594                  *    one side of the object name is unknown, with
4595                  *    the same mode and size.  Keep the ones that
4596                  *    do not match these criteria.  They have real
4597                  *    differences.
4598                  *
4599                  * 2. At this point, the file is known to be modified,
4600                  *    with the same mode and size, and the object
4601                  *    name of one side is unknown.  Need to inspect
4602                  *    the identical contents.
4603                  */
4604                 if (!DIFF_FILE_VALID(p->one) || /* (1) */
4605                     !DIFF_FILE_VALID(p->two) ||
4606                     (p->one->sha1_valid && p->two->sha1_valid) ||
4607                     (p->one->mode != p->two->mode) ||
4608                     diff_populate_filespec(p->one, 1) ||
4609                     diff_populate_filespec(p->two, 1) ||
4610                     (p->one->size != p->two->size) ||
4611                     !diff_filespec_is_identical(p->one, p->two)) /* (2) */
4612                         diff_q(&outq, p);
4613                 else {
4614                         /*
4615                          * The caller can subtract 1 from skip_stat_unmatch
4616                          * to determine how many paths were dirty only
4617                          * due to stat info mismatch.
4618                          */
4619                         if (!DIFF_OPT_TST(diffopt, NO_INDEX))
4620                                 diffopt->skip_stat_unmatch++;
4621                         diff_free_filepair(p);
4622                 }
4623         }
4624         free(q->queue);
4625         *q = outq;
4626 }
4627
4628 static int diffnamecmp(const void *a_, const void *b_)
4629 {
4630         const struct diff_filepair *a = *((const struct diff_filepair **)a_);
4631         const struct diff_filepair *b = *((const struct diff_filepair **)b_);
4632         const char *name_a, *name_b;
4633
4634         name_a = a->one ? a->one->path : a->two->path;
4635         name_b = b->one ? b->one->path : b->two->path;
4636         return strcmp(name_a, name_b);
4637 }
4638
4639 void diffcore_fix_diff_index(struct diff_options *options)
4640 {
4641         struct diff_queue_struct *q = &diff_queued_diff;
4642         qsort(q->queue, q->nr, sizeof(q->queue[0]), diffnamecmp);
4643 }
4644
4645 void diffcore_std(struct diff_options *options)
4646 {
4647         if (options->skip_stat_unmatch)
4648                 diffcore_skip_stat_unmatch(options);
4649         if (!options->found_follow) {
4650                 /* See try_to_follow_renames() in tree-diff.c */
4651                 if (options->break_opt != -1)
4652                         diffcore_break(options->break_opt);
4653                 if (options->detect_rename)
4654                         diffcore_rename(options);
4655                 if (options->break_opt != -1)
4656                         diffcore_merge_broken();
4657         }
4658         if (options->pickaxe)
4659                 diffcore_pickaxe(options);
4660         if (options->orderfile)
4661                 diffcore_order(options->orderfile);
4662         if (!options->found_follow)
4663                 /* See try_to_follow_renames() in tree-diff.c */
4664                 diff_resolve_rename_copy();
4665         diffcore_apply_filter(options->filter);
4666
4667         if (diff_queued_diff.nr && !DIFF_OPT_TST(options, DIFF_FROM_CONTENTS))
4668                 DIFF_OPT_SET(options, HAS_CHANGES);
4669         else
4670                 DIFF_OPT_CLR(options, HAS_CHANGES);
4671
4672         options->found_follow = 0;
4673 }
4674
4675 int diff_result_code(struct diff_options *opt, int status)
4676 {
4677         int result = 0;
4678
4679         diff_warn_rename_limit("diff.renameLimit",
4680                                opt->needed_rename_limit,
4681                                opt->degraded_cc_to_c);
4682         if (!DIFF_OPT_TST(opt, EXIT_WITH_STATUS) &&
4683             !(opt->output_format & DIFF_FORMAT_CHECKDIFF))
4684                 return status;
4685         if (DIFF_OPT_TST(opt, EXIT_WITH_STATUS) &&
4686             DIFF_OPT_TST(opt, HAS_CHANGES))
4687                 result |= 01;
4688         if ((opt->output_format & DIFF_FORMAT_CHECKDIFF) &&
4689             DIFF_OPT_TST(opt, CHECK_FAILED))
4690                 result |= 02;
4691         return result;
4692 }
4693
4694 int diff_can_quit_early(struct diff_options *opt)
4695 {
4696         return (DIFF_OPT_TST(opt, QUICK) &&
4697                 !opt->filter &&
4698                 DIFF_OPT_TST(opt, HAS_CHANGES));
4699 }
4700
4701 /*
4702  * Shall changes to this submodule be ignored?
4703  *
4704  * Submodule changes can be configured to be ignored separately for each path,
4705  * but that configuration can be overridden from the command line.
4706  */
4707 static int is_submodule_ignored(const char *path, struct diff_options *options)
4708 {
4709         int ignored = 0;
4710         unsigned orig_flags = options->flags;
4711         if (!DIFF_OPT_TST(options, OVERRIDE_SUBMODULE_CONFIG))
4712                 set_diffopt_flags_from_submodule_config(options, path);
4713         if (DIFF_OPT_TST(options, IGNORE_SUBMODULES))
4714                 ignored = 1;
4715         options->flags = orig_flags;
4716         return ignored;
4717 }
4718
4719 void diff_addremove(struct diff_options *options,
4720                     int addremove, unsigned mode,
4721                     const unsigned char *sha1,
4722                     int sha1_valid,
4723                     const char *concatpath, unsigned dirty_submodule)
4724 {
4725         struct diff_filespec *one, *two;
4726
4727         if (S_ISGITLINK(mode) && is_submodule_ignored(concatpath, options))
4728                 return;
4729
4730         /* This may look odd, but it is a preparation for
4731          * feeding "there are unchanged files which should
4732          * not produce diffs, but when you are doing copy
4733          * detection you would need them, so here they are"
4734          * entries to the diff-core.  They will be prefixed
4735          * with something like '=' or '*' (I haven't decided
4736          * which but should not make any difference).
4737          * Feeding the same new and old to diff_change()
4738          * also has the same effect.
4739          * Before the final output happens, they are pruned after
4740          * merged into rename/copy pairs as appropriate.
4741          */
4742         if (DIFF_OPT_TST(options, REVERSE_DIFF))
4743                 addremove = (addremove == '+' ? '-' :
4744                              addremove == '-' ? '+' : addremove);
4745
4746         if (options->prefix &&
4747             strncmp(concatpath, options->prefix, options->prefix_length))
4748                 return;
4749
4750         one = alloc_filespec(concatpath);
4751         two = alloc_filespec(concatpath);
4752
4753         if (addremove != '+')
4754                 fill_filespec(one, sha1, sha1_valid, mode);
4755         if (addremove != '-') {
4756                 fill_filespec(two, sha1, sha1_valid, mode);
4757                 two->dirty_submodule = dirty_submodule;
4758         }
4759
4760         diff_queue(&diff_queued_diff, one, two);
4761         if (!DIFF_OPT_TST(options, DIFF_FROM_CONTENTS))
4762                 DIFF_OPT_SET(options, HAS_CHANGES);
4763 }
4764
4765 void diff_change(struct diff_options *options,
4766                  unsigned old_mode, unsigned new_mode,
4767                  const unsigned char *old_sha1,
4768                  const unsigned char *new_sha1,
4769                  int old_sha1_valid, int new_sha1_valid,
4770                  const char *concatpath,
4771                  unsigned old_dirty_submodule, unsigned new_dirty_submodule)
4772 {
4773         struct diff_filespec *one, *two;
4774
4775         if (S_ISGITLINK(old_mode) && S_ISGITLINK(new_mode) &&
4776             is_submodule_ignored(concatpath, options))
4777                 return;
4778
4779         if (DIFF_OPT_TST(options, REVERSE_DIFF)) {
4780                 unsigned tmp;
4781                 const unsigned char *tmp_c;
4782                 tmp = old_mode; old_mode = new_mode; new_mode = tmp;
4783                 tmp_c = old_sha1; old_sha1 = new_sha1; new_sha1 = tmp_c;
4784                 tmp = old_sha1_valid; old_sha1_valid = new_sha1_valid;
4785                         new_sha1_valid = tmp;
4786                 tmp = old_dirty_submodule; old_dirty_submodule = new_dirty_submodule;
4787                         new_dirty_submodule = tmp;
4788         }
4789
4790         if (options->prefix &&
4791             strncmp(concatpath, options->prefix, options->prefix_length))
4792                 return;
4793
4794         one = alloc_filespec(concatpath);
4795         two = alloc_filespec(concatpath);
4796         fill_filespec(one, old_sha1, old_sha1_valid, old_mode);
4797         fill_filespec(two, new_sha1, new_sha1_valid, new_mode);
4798         one->dirty_submodule = old_dirty_submodule;
4799         two->dirty_submodule = new_dirty_submodule;
4800
4801         diff_queue(&diff_queued_diff, one, two);
4802         if (!DIFF_OPT_TST(options, DIFF_FROM_CONTENTS))
4803                 DIFF_OPT_SET(options, HAS_CHANGES);
4804 }
4805
4806 struct diff_filepair *diff_unmerge(struct diff_options *options, const char *path)
4807 {
4808         struct diff_filepair *pair;
4809         struct diff_filespec *one, *two;
4810
4811         if (options->prefix &&
4812             strncmp(path, options->prefix, options->prefix_length))
4813                 return NULL;
4814
4815         one = alloc_filespec(path);
4816         two = alloc_filespec(path);
4817         pair = diff_queue(&diff_queued_diff, one, two);
4818         pair->is_unmerged = 1;
4819         return pair;
4820 }
4821
4822 static char *run_textconv(const char *pgm, struct diff_filespec *spec,
4823                 size_t *outsize)
4824 {
4825         struct diff_tempfile *temp;
4826         const char *argv[3];
4827         const char **arg = argv;
4828         struct child_process child;
4829         struct strbuf buf = STRBUF_INIT;
4830         int err = 0;
4831
4832         temp = prepare_temp_file(spec->path, spec);
4833         *arg++ = pgm;
4834         *arg++ = temp->name;
4835         *arg = NULL;
4836
4837         memset(&child, 0, sizeof(child));
4838         child.use_shell = 1;
4839         child.argv = argv;
4840         child.out = -1;
4841         if (start_command(&child)) {
4842                 remove_tempfile();
4843                 return NULL;
4844         }
4845
4846         if (strbuf_read(&buf, child.out, 0) < 0)
4847                 err = error("error reading from textconv command '%s'", pgm);
4848         close(child.out);
4849
4850         if (finish_command(&child) || err) {
4851                 strbuf_release(&buf);
4852                 remove_tempfile();
4853                 return NULL;
4854         }
4855         remove_tempfile();
4856
4857         return strbuf_detach(&buf, outsize);
4858 }
4859
4860 size_t fill_textconv(struct userdiff_driver *driver,
4861                      struct diff_filespec *df,
4862                      char **outbuf)
4863 {
4864         size_t size;
4865
4866         if (!driver || !driver->textconv) {
4867                 if (!DIFF_FILE_VALID(df)) {
4868                         *outbuf = "";
4869                         return 0;
4870                 }
4871                 if (diff_populate_filespec(df, 0))
4872                         die("unable to read files to diff");
4873                 *outbuf = df->data;
4874                 return df->size;
4875         }
4876
4877         if (driver->textconv_cache && df->sha1_valid) {
4878                 *outbuf = notes_cache_get(driver->textconv_cache, df->sha1,
4879                                           &size);
4880                 if (*outbuf)
4881                         return size;
4882         }
4883
4884         *outbuf = run_textconv(driver->textconv, df, &size);
4885         if (!*outbuf)
4886                 die("unable to read files to diff");
4887
4888         if (driver->textconv_cache && df->sha1_valid) {
4889                 /* ignore errors, as we might be in a readonly repository */
4890                 notes_cache_put(driver->textconv_cache, df->sha1, *outbuf,
4891                                 size);
4892                 /*
4893                  * we could save up changes and flush them all at the end,
4894                  * but we would need an extra call after all diffing is done.
4895                  * Since generating a cache entry is the slow path anyway,
4896                  * this extra overhead probably isn't a big deal.
4897                  */
4898                 notes_cache_write(driver->textconv_cache);
4899         }
4900
4901         return size;
4902 }
4903
4904 void setup_diff_pager(struct diff_options *opt)
4905 {
4906         /*
4907          * If the user asked for our exit code, then either they want --quiet
4908          * or --exit-code. We should definitely not bother with a pager in the
4909          * former case, as we will generate no output. Since we still properly
4910          * report our exit code even when a pager is run, we _could_ run a
4911          * pager with --exit-code. But since we have not done so historically,
4912          * and because it is easy to find people oneline advising "git diff
4913          * --exit-code" in hooks and other scripts, we do not do so.
4914          */
4915         if (!DIFF_OPT_TST(opt, EXIT_WITH_STATUS) &&
4916             check_pager_config("diff") != 0)
4917                 setup_pager();
4918 }