Merge branch 'nd/clear-gitenv-upon-use-of-alias'
[git] / diff.c
1 /*
2  * Copyright (C) 2005 Junio C Hamano
3  */
4 #include "cache.h"
5 #include "tempfile.h"
6 #include "quote.h"
7 #include "diff.h"
8 #include "diffcore.h"
9 #include "delta.h"
10 #include "xdiff-interface.h"
11 #include "color.h"
12 #include "attr.h"
13 #include "run-command.h"
14 #include "utf8.h"
15 #include "userdiff.h"
16 #include "submodule-config.h"
17 #include "submodule.h"
18 #include "ll-merge.h"
19 #include "string-list.h"
20 #include "argv-array.h"
21
22 #ifdef NO_FAST_WORKING_DIRECTORY
23 #define FAST_WORKING_DIRECTORY 0
24 #else
25 #define FAST_WORKING_DIRECTORY 1
26 #endif
27
28 static int diff_detect_rename_default;
29 static int diff_rename_limit_default = 400;
30 static int diff_suppress_blank_empty;
31 static int diff_use_color_default = -1;
32 static int diff_context_default = 3;
33 static const char *diff_word_regex_cfg;
34 static const char *external_diff_cmd_cfg;
35 static const char *diff_order_file_cfg;
36 int diff_auto_refresh_index = 1;
37 static int diff_mnemonic_prefix;
38 static int diff_no_prefix;
39 static int diff_stat_graph_width;
40 static int diff_dirstat_permille_default = 30;
41 static struct diff_options default_diff_options;
42 static long diff_algorithm;
43
44 static char diff_colors[][COLOR_MAXLEN] = {
45         GIT_COLOR_RESET,
46         GIT_COLOR_NORMAL,       /* CONTEXT */
47         GIT_COLOR_BOLD,         /* METAINFO */
48         GIT_COLOR_CYAN,         /* FRAGINFO */
49         GIT_COLOR_RED,          /* OLD */
50         GIT_COLOR_GREEN,        /* NEW */
51         GIT_COLOR_YELLOW,       /* COMMIT */
52         GIT_COLOR_BG_RED,       /* WHITESPACE */
53         GIT_COLOR_NORMAL,       /* FUNCINFO */
54 };
55
56 static int parse_diff_color_slot(const char *var)
57 {
58         if (!strcasecmp(var, "context") || !strcasecmp(var, "plain"))
59                 return DIFF_CONTEXT;
60         if (!strcasecmp(var, "meta"))
61                 return DIFF_METAINFO;
62         if (!strcasecmp(var, "frag"))
63                 return DIFF_FRAGINFO;
64         if (!strcasecmp(var, "old"))
65                 return DIFF_FILE_OLD;
66         if (!strcasecmp(var, "new"))
67                 return DIFF_FILE_NEW;
68         if (!strcasecmp(var, "commit"))
69                 return DIFF_COMMIT;
70         if (!strcasecmp(var, "whitespace"))
71                 return DIFF_WHITESPACE;
72         if (!strcasecmp(var, "func"))
73                 return DIFF_FUNCINFO;
74         return -1;
75 }
76
77 static int parse_dirstat_params(struct diff_options *options, const char *params_string,
78                                 struct strbuf *errmsg)
79 {
80         char *params_copy = xstrdup(params_string);
81         struct string_list params = STRING_LIST_INIT_NODUP;
82         int ret = 0;
83         int i;
84
85         if (*params_copy)
86                 string_list_split_in_place(&params, params_copy, ',', -1);
87         for (i = 0; i < params.nr; i++) {
88                 const char *p = params.items[i].string;
89                 if (!strcmp(p, "changes")) {
90                         DIFF_OPT_CLR(options, DIRSTAT_BY_LINE);
91                         DIFF_OPT_CLR(options, DIRSTAT_BY_FILE);
92                 } else if (!strcmp(p, "lines")) {
93                         DIFF_OPT_SET(options, DIRSTAT_BY_LINE);
94                         DIFF_OPT_CLR(options, DIRSTAT_BY_FILE);
95                 } else if (!strcmp(p, "files")) {
96                         DIFF_OPT_CLR(options, DIRSTAT_BY_LINE);
97                         DIFF_OPT_SET(options, DIRSTAT_BY_FILE);
98                 } else if (!strcmp(p, "noncumulative")) {
99                         DIFF_OPT_CLR(options, DIRSTAT_CUMULATIVE);
100                 } else if (!strcmp(p, "cumulative")) {
101                         DIFF_OPT_SET(options, DIRSTAT_CUMULATIVE);
102                 } else if (isdigit(*p)) {
103                         char *end;
104                         int permille = strtoul(p, &end, 10) * 10;
105                         if (*end == '.' && isdigit(*++end)) {
106                                 /* only use first digit */
107                                 permille += *end - '0';
108                                 /* .. and ignore any further digits */
109                                 while (isdigit(*++end))
110                                         ; /* nothing */
111                         }
112                         if (!*end)
113                                 options->dirstat_permille = permille;
114                         else {
115                                 strbuf_addf(errmsg, _("  Failed to parse dirstat cut-off percentage '%s'\n"),
116                                             p);
117                                 ret++;
118                         }
119                 } else {
120                         strbuf_addf(errmsg, _("  Unknown dirstat parameter '%s'\n"), p);
121                         ret++;
122                 }
123
124         }
125         string_list_clear(&params, 0);
126         free(params_copy);
127         return ret;
128 }
129
130 static int parse_submodule_params(struct diff_options *options, const char *value)
131 {
132         if (!strcmp(value, "log"))
133                 DIFF_OPT_SET(options, SUBMODULE_LOG);
134         else if (!strcmp(value, "short"))
135                 DIFF_OPT_CLR(options, SUBMODULE_LOG);
136         else
137                 return -1;
138         return 0;
139 }
140
141 static int git_config_rename(const char *var, const char *value)
142 {
143         if (!value)
144                 return DIFF_DETECT_RENAME;
145         if (!strcasecmp(value, "copies") || !strcasecmp(value, "copy"))
146                 return  DIFF_DETECT_COPY;
147         return git_config_bool(var,value) ? DIFF_DETECT_RENAME : 0;
148 }
149
150 long parse_algorithm_value(const char *value)
151 {
152         if (!value)
153                 return -1;
154         else if (!strcasecmp(value, "myers") || !strcasecmp(value, "default"))
155                 return 0;
156         else if (!strcasecmp(value, "minimal"))
157                 return XDF_NEED_MINIMAL;
158         else if (!strcasecmp(value, "patience"))
159                 return XDF_PATIENCE_DIFF;
160         else if (!strcasecmp(value, "histogram"))
161                 return XDF_HISTOGRAM_DIFF;
162         return -1;
163 }
164
165 /*
166  * These are to give UI layer defaults.
167  * The core-level commands such as git-diff-files should
168  * never be affected by the setting of diff.renames
169  * the user happens to have in the configuration file.
170  */
171 int git_diff_ui_config(const char *var, const char *value, void *cb)
172 {
173         if (!strcmp(var, "diff.color") || !strcmp(var, "color.diff")) {
174                 diff_use_color_default = git_config_colorbool(var, value);
175                 return 0;
176         }
177         if (!strcmp(var, "diff.context")) {
178                 diff_context_default = git_config_int(var, value);
179                 if (diff_context_default < 0)
180                         return -1;
181                 return 0;
182         }
183         if (!strcmp(var, "diff.renames")) {
184                 diff_detect_rename_default = git_config_rename(var, value);
185                 return 0;
186         }
187         if (!strcmp(var, "diff.autorefreshindex")) {
188                 diff_auto_refresh_index = git_config_bool(var, value);
189                 return 0;
190         }
191         if (!strcmp(var, "diff.mnemonicprefix")) {
192                 diff_mnemonic_prefix = git_config_bool(var, value);
193                 return 0;
194         }
195         if (!strcmp(var, "diff.noprefix")) {
196                 diff_no_prefix = git_config_bool(var, value);
197                 return 0;
198         }
199         if (!strcmp(var, "diff.statgraphwidth")) {
200                 diff_stat_graph_width = git_config_int(var, value);
201                 return 0;
202         }
203         if (!strcmp(var, "diff.external"))
204                 return git_config_string(&external_diff_cmd_cfg, var, value);
205         if (!strcmp(var, "diff.wordregex"))
206                 return git_config_string(&diff_word_regex_cfg, var, value);
207         if (!strcmp(var, "diff.orderfile"))
208                 return git_config_pathname(&diff_order_file_cfg, var, value);
209
210         if (!strcmp(var, "diff.ignoresubmodules"))
211                 handle_ignore_submodules_arg(&default_diff_options, value);
212
213         if (!strcmp(var, "diff.submodule")) {
214                 if (parse_submodule_params(&default_diff_options, value))
215                         warning(_("Unknown value for 'diff.submodule' config variable: '%s'"),
216                                 value);
217                 return 0;
218         }
219
220         if (!strcmp(var, "diff.algorithm")) {
221                 diff_algorithm = parse_algorithm_value(value);
222                 if (diff_algorithm < 0)
223                         return -1;
224                 return 0;
225         }
226
227         if (git_color_config(var, value, cb) < 0)
228                 return -1;
229
230         return git_diff_basic_config(var, value, cb);
231 }
232
233 int git_diff_basic_config(const char *var, const char *value, void *cb)
234 {
235         const char *name;
236
237         if (!strcmp(var, "diff.renamelimit")) {
238                 diff_rename_limit_default = git_config_int(var, value);
239                 return 0;
240         }
241
242         if (userdiff_config(var, value) < 0)
243                 return -1;
244
245         if (skip_prefix(var, "diff.color.", &name) ||
246             skip_prefix(var, "color.diff.", &name)) {
247                 int slot = parse_diff_color_slot(name);
248                 if (slot < 0)
249                         return 0;
250                 if (!value)
251                         return config_error_nonbool(var);
252                 return color_parse(value, diff_colors[slot]);
253         }
254
255         /* like GNU diff's --suppress-blank-empty option  */
256         if (!strcmp(var, "diff.suppressblankempty") ||
257                         /* for backwards compatibility */
258                         !strcmp(var, "diff.suppress-blank-empty")) {
259                 diff_suppress_blank_empty = git_config_bool(var, value);
260                 return 0;
261         }
262
263         if (!strcmp(var, "diff.dirstat")) {
264                 struct strbuf errmsg = STRBUF_INIT;
265                 default_diff_options.dirstat_permille = diff_dirstat_permille_default;
266                 if (parse_dirstat_params(&default_diff_options, value, &errmsg))
267                         warning(_("Found errors in 'diff.dirstat' config variable:\n%s"),
268                                 errmsg.buf);
269                 strbuf_release(&errmsg);
270                 diff_dirstat_permille_default = default_diff_options.dirstat_permille;
271                 return 0;
272         }
273
274         if (starts_with(var, "submodule."))
275                 return parse_submodule_config_option(var, value);
276
277         return git_default_config(var, value, cb);
278 }
279
280 static char *quote_two(const char *one, const char *two)
281 {
282         int need_one = quote_c_style(one, NULL, NULL, 1);
283         int need_two = quote_c_style(two, NULL, NULL, 1);
284         struct strbuf res = STRBUF_INIT;
285
286         if (need_one + need_two) {
287                 strbuf_addch(&res, '"');
288                 quote_c_style(one, &res, NULL, 1);
289                 quote_c_style(two, &res, NULL, 1);
290                 strbuf_addch(&res, '"');
291         } else {
292                 strbuf_addstr(&res, one);
293                 strbuf_addstr(&res, two);
294         }
295         return strbuf_detach(&res, NULL);
296 }
297
298 static const char *external_diff(void)
299 {
300         static const char *external_diff_cmd = NULL;
301         static int done_preparing = 0;
302
303         if (done_preparing)
304                 return external_diff_cmd;
305         external_diff_cmd = getenv("GIT_EXTERNAL_DIFF");
306         if (!external_diff_cmd)
307                 external_diff_cmd = external_diff_cmd_cfg;
308         done_preparing = 1;
309         return external_diff_cmd;
310 }
311
312 /*
313  * Keep track of files used for diffing. Sometimes such an entry
314  * refers to a temporary file, sometimes to an existing file, and
315  * sometimes to "/dev/null".
316  */
317 static struct diff_tempfile {
318         /*
319          * filename external diff should read from, or NULL if this
320          * entry is currently not in use:
321          */
322         const char *name;
323
324         char hex[GIT_SHA1_HEXSZ + 1];
325         char mode[10];
326
327         /*
328          * If this diff_tempfile instance refers to a temporary file,
329          * this tempfile object is used to manage its lifetime.
330          */
331         struct tempfile tempfile;
332 } diff_temp[2];
333
334 typedef unsigned long (*sane_truncate_fn)(char *line, unsigned long len);
335
336 struct emit_callback {
337         int color_diff;
338         unsigned ws_rule;
339         int blank_at_eof_in_preimage;
340         int blank_at_eof_in_postimage;
341         int lno_in_preimage;
342         int lno_in_postimage;
343         sane_truncate_fn truncate;
344         const char **label_path;
345         struct diff_words_data *diff_words;
346         struct diff_options *opt;
347         int *found_changesp;
348         struct strbuf *header;
349 };
350
351 static int count_lines(const char *data, int size)
352 {
353         int count, ch, completely_empty = 1, nl_just_seen = 0;
354         count = 0;
355         while (0 < size--) {
356                 ch = *data++;
357                 if (ch == '\n') {
358                         count++;
359                         nl_just_seen = 1;
360                         completely_empty = 0;
361                 }
362                 else {
363                         nl_just_seen = 0;
364                         completely_empty = 0;
365                 }
366         }
367         if (completely_empty)
368                 return 0;
369         if (!nl_just_seen)
370                 count++; /* no trailing newline */
371         return count;
372 }
373
374 static int fill_mmfile(mmfile_t *mf, struct diff_filespec *one)
375 {
376         if (!DIFF_FILE_VALID(one)) {
377                 mf->ptr = (char *)""; /* does not matter */
378                 mf->size = 0;
379                 return 0;
380         }
381         else if (diff_populate_filespec(one, 0))
382                 return -1;
383
384         mf->ptr = one->data;
385         mf->size = one->size;
386         return 0;
387 }
388
389 /* like fill_mmfile, but only for size, so we can avoid retrieving blob */
390 static unsigned long diff_filespec_size(struct diff_filespec *one)
391 {
392         if (!DIFF_FILE_VALID(one))
393                 return 0;
394         diff_populate_filespec(one, CHECK_SIZE_ONLY);
395         return one->size;
396 }
397
398 static int count_trailing_blank(mmfile_t *mf, unsigned ws_rule)
399 {
400         char *ptr = mf->ptr;
401         long size = mf->size;
402         int cnt = 0;
403
404         if (!size)
405                 return cnt;
406         ptr += size - 1; /* pointing at the very end */
407         if (*ptr != '\n')
408                 ; /* incomplete line */
409         else
410                 ptr--; /* skip the last LF */
411         while (mf->ptr < ptr) {
412                 char *prev_eol;
413                 for (prev_eol = ptr; mf->ptr <= prev_eol; prev_eol--)
414                         if (*prev_eol == '\n')
415                                 break;
416                 if (!ws_blank_line(prev_eol + 1, ptr - prev_eol, ws_rule))
417                         break;
418                 cnt++;
419                 ptr = prev_eol - 1;
420         }
421         return cnt;
422 }
423
424 static void check_blank_at_eof(mmfile_t *mf1, mmfile_t *mf2,
425                                struct emit_callback *ecbdata)
426 {
427         int l1, l2, at;
428         unsigned ws_rule = ecbdata->ws_rule;
429         l1 = count_trailing_blank(mf1, ws_rule);
430         l2 = count_trailing_blank(mf2, ws_rule);
431         if (l2 <= l1) {
432                 ecbdata->blank_at_eof_in_preimage = 0;
433                 ecbdata->blank_at_eof_in_postimage = 0;
434                 return;
435         }
436         at = count_lines(mf1->ptr, mf1->size);
437         ecbdata->blank_at_eof_in_preimage = (at - l1) + 1;
438
439         at = count_lines(mf2->ptr, mf2->size);
440         ecbdata->blank_at_eof_in_postimage = (at - l2) + 1;
441 }
442
443 static void emit_line_0(struct diff_options *o, const char *set, const char *reset,
444                         int first, const char *line, int len)
445 {
446         int has_trailing_newline, has_trailing_carriage_return;
447         int nofirst;
448         FILE *file = o->file;
449
450         fputs(diff_line_prefix(o), file);
451
452         if (len == 0) {
453                 has_trailing_newline = (first == '\n');
454                 has_trailing_carriage_return = (!has_trailing_newline &&
455                                                 (first == '\r'));
456                 nofirst = has_trailing_newline || has_trailing_carriage_return;
457         } else {
458                 has_trailing_newline = (len > 0 && line[len-1] == '\n');
459                 if (has_trailing_newline)
460                         len--;
461                 has_trailing_carriage_return = (len > 0 && line[len-1] == '\r');
462                 if (has_trailing_carriage_return)
463                         len--;
464                 nofirst = 0;
465         }
466
467         if (len || !nofirst) {
468                 fputs(set, file);
469                 if (!nofirst)
470                         fputc(first, file);
471                 fwrite(line, len, 1, file);
472                 fputs(reset, file);
473         }
474         if (has_trailing_carriage_return)
475                 fputc('\r', file);
476         if (has_trailing_newline)
477                 fputc('\n', file);
478 }
479
480 static void emit_line(struct diff_options *o, const char *set, const char *reset,
481                       const char *line, int len)
482 {
483         emit_line_0(o, set, reset, line[0], line+1, len-1);
484 }
485
486 static int new_blank_line_at_eof(struct emit_callback *ecbdata, const char *line, int len)
487 {
488         if (!((ecbdata->ws_rule & WS_BLANK_AT_EOF) &&
489               ecbdata->blank_at_eof_in_preimage &&
490               ecbdata->blank_at_eof_in_postimage &&
491               ecbdata->blank_at_eof_in_preimage <= ecbdata->lno_in_preimage &&
492               ecbdata->blank_at_eof_in_postimage <= ecbdata->lno_in_postimage))
493                 return 0;
494         return ws_blank_line(line, len, ecbdata->ws_rule);
495 }
496
497 static void emit_line_checked(const char *reset,
498                               struct emit_callback *ecbdata,
499                               const char *line, int len,
500                               enum color_diff color,
501                               unsigned ws_error_highlight,
502                               char sign)
503 {
504         const char *set = diff_get_color(ecbdata->color_diff, color);
505         const char *ws = NULL;
506
507         if (ecbdata->opt->ws_error_highlight & ws_error_highlight) {
508                 ws = diff_get_color(ecbdata->color_diff, DIFF_WHITESPACE);
509                 if (!*ws)
510                         ws = NULL;
511         }
512
513         if (!ws)
514                 emit_line_0(ecbdata->opt, set, reset, sign, line, len);
515         else if (sign == '+' && new_blank_line_at_eof(ecbdata, line, len))
516                 /* Blank line at EOF - paint '+' as well */
517                 emit_line_0(ecbdata->opt, ws, reset, sign, line, len);
518         else {
519                 /* Emit just the prefix, then the rest. */
520                 emit_line_0(ecbdata->opt, set, reset, sign, "", 0);
521                 ws_check_emit(line, len, ecbdata->ws_rule,
522                               ecbdata->opt->file, set, reset, ws);
523         }
524 }
525
526 static void emit_add_line(const char *reset,
527                           struct emit_callback *ecbdata,
528                           const char *line, int len)
529 {
530         emit_line_checked(reset, ecbdata, line, len,
531                           DIFF_FILE_NEW, WSEH_NEW, '+');
532 }
533
534 static void emit_del_line(const char *reset,
535                           struct emit_callback *ecbdata,
536                           const char *line, int len)
537 {
538         emit_line_checked(reset, ecbdata, line, len,
539                           DIFF_FILE_OLD, WSEH_OLD, '-');
540 }
541
542 static void emit_context_line(const char *reset,
543                               struct emit_callback *ecbdata,
544                               const char *line, int len)
545 {
546         emit_line_checked(reset, ecbdata, line, len,
547                           DIFF_CONTEXT, WSEH_CONTEXT, ' ');
548 }
549
550 static void emit_hunk_header(struct emit_callback *ecbdata,
551                              const char *line, int len)
552 {
553         const char *context = diff_get_color(ecbdata->color_diff, DIFF_CONTEXT);
554         const char *frag = diff_get_color(ecbdata->color_diff, DIFF_FRAGINFO);
555         const char *func = diff_get_color(ecbdata->color_diff, DIFF_FUNCINFO);
556         const char *reset = diff_get_color(ecbdata->color_diff, DIFF_RESET);
557         static const char atat[2] = { '@', '@' };
558         const char *cp, *ep;
559         struct strbuf msgbuf = STRBUF_INIT;
560         int org_len = len;
561         int i = 1;
562
563         /*
564          * As a hunk header must begin with "@@ -<old>, +<new> @@",
565          * it always is at least 10 bytes long.
566          */
567         if (len < 10 ||
568             memcmp(line, atat, 2) ||
569             !(ep = memmem(line + 2, len - 2, atat, 2))) {
570                 emit_line(ecbdata->opt, context, reset, line, len);
571                 return;
572         }
573         ep += 2; /* skip over @@ */
574
575         /* The hunk header in fraginfo color */
576         strbuf_addstr(&msgbuf, frag);
577         strbuf_add(&msgbuf, line, ep - line);
578         strbuf_addstr(&msgbuf, reset);
579
580         /*
581          * trailing "\r\n"
582          */
583         for ( ; i < 3; i++)
584                 if (line[len - i] == '\r' || line[len - i] == '\n')
585                         len--;
586
587         /* blank before the func header */
588         for (cp = ep; ep - line < len; ep++)
589                 if (*ep != ' ' && *ep != '\t')
590                         break;
591         if (ep != cp) {
592                 strbuf_addstr(&msgbuf, context);
593                 strbuf_add(&msgbuf, cp, ep - cp);
594                 strbuf_addstr(&msgbuf, reset);
595         }
596
597         if (ep < line + len) {
598                 strbuf_addstr(&msgbuf, func);
599                 strbuf_add(&msgbuf, ep, line + len - ep);
600                 strbuf_addstr(&msgbuf, reset);
601         }
602
603         strbuf_add(&msgbuf, line + len, org_len - len);
604         emit_line(ecbdata->opt, "", "", msgbuf.buf, msgbuf.len);
605         strbuf_release(&msgbuf);
606 }
607
608 static struct diff_tempfile *claim_diff_tempfile(void) {
609         int i;
610         for (i = 0; i < ARRAY_SIZE(diff_temp); i++)
611                 if (!diff_temp[i].name)
612                         return diff_temp + i;
613         die("BUG: diff is failing to clean up its tempfiles");
614 }
615
616 static void remove_tempfile(void)
617 {
618         int i;
619         for (i = 0; i < ARRAY_SIZE(diff_temp); i++) {
620                 if (is_tempfile_active(&diff_temp[i].tempfile))
621                         delete_tempfile(&diff_temp[i].tempfile);
622                 diff_temp[i].name = NULL;
623         }
624 }
625
626 static void print_line_count(FILE *file, int count)
627 {
628         switch (count) {
629         case 0:
630                 fprintf(file, "0,0");
631                 break;
632         case 1:
633                 fprintf(file, "1");
634                 break;
635         default:
636                 fprintf(file, "1,%d", count);
637                 break;
638         }
639 }
640
641 static void emit_rewrite_lines(struct emit_callback *ecb,
642                                int prefix, const char *data, int size)
643 {
644         const char *endp = NULL;
645         static const char *nneof = " No newline at end of file\n";
646         const char *reset = diff_get_color(ecb->color_diff, DIFF_RESET);
647
648         while (0 < size) {
649                 int len;
650
651                 endp = memchr(data, '\n', size);
652                 len = endp ? (endp - data + 1) : size;
653                 if (prefix != '+') {
654                         ecb->lno_in_preimage++;
655                         emit_del_line(reset, ecb, data, len);
656                 } else {
657                         ecb->lno_in_postimage++;
658                         emit_add_line(reset, ecb, data, len);
659                 }
660                 size -= len;
661                 data += len;
662         }
663         if (!endp) {
664                 const char *context = diff_get_color(ecb->color_diff,
665                                                      DIFF_CONTEXT);
666                 putc('\n', ecb->opt->file);
667                 emit_line_0(ecb->opt, context, reset, '\\',
668                             nneof, strlen(nneof));
669         }
670 }
671
672 static void emit_rewrite_diff(const char *name_a,
673                               const char *name_b,
674                               struct diff_filespec *one,
675                               struct diff_filespec *two,
676                               struct userdiff_driver *textconv_one,
677                               struct userdiff_driver *textconv_two,
678                               struct diff_options *o)
679 {
680         int lc_a, lc_b;
681         const char *name_a_tab, *name_b_tab;
682         const char *metainfo = diff_get_color(o->use_color, DIFF_METAINFO);
683         const char *fraginfo = diff_get_color(o->use_color, DIFF_FRAGINFO);
684         const char *reset = diff_get_color(o->use_color, DIFF_RESET);
685         static struct strbuf a_name = STRBUF_INIT, b_name = STRBUF_INIT;
686         const char *a_prefix, *b_prefix;
687         char *data_one, *data_two;
688         size_t size_one, size_two;
689         struct emit_callback ecbdata;
690         const char *line_prefix = diff_line_prefix(o);
691
692         if (diff_mnemonic_prefix && DIFF_OPT_TST(o, REVERSE_DIFF)) {
693                 a_prefix = o->b_prefix;
694                 b_prefix = o->a_prefix;
695         } else {
696                 a_prefix = o->a_prefix;
697                 b_prefix = o->b_prefix;
698         }
699
700         name_a += (*name_a == '/');
701         name_b += (*name_b == '/');
702         name_a_tab = strchr(name_a, ' ') ? "\t" : "";
703         name_b_tab = strchr(name_b, ' ') ? "\t" : "";
704
705         strbuf_reset(&a_name);
706         strbuf_reset(&b_name);
707         quote_two_c_style(&a_name, a_prefix, name_a, 0);
708         quote_two_c_style(&b_name, b_prefix, name_b, 0);
709
710         size_one = fill_textconv(textconv_one, one, &data_one);
711         size_two = fill_textconv(textconv_two, two, &data_two);
712
713         memset(&ecbdata, 0, sizeof(ecbdata));
714         ecbdata.color_diff = want_color(o->use_color);
715         ecbdata.found_changesp = &o->found_changes;
716         ecbdata.ws_rule = whitespace_rule(name_b);
717         ecbdata.opt = o;
718         if (ecbdata.ws_rule & WS_BLANK_AT_EOF) {
719                 mmfile_t mf1, mf2;
720                 mf1.ptr = (char *)data_one;
721                 mf2.ptr = (char *)data_two;
722                 mf1.size = size_one;
723                 mf2.size = size_two;
724                 check_blank_at_eof(&mf1, &mf2, &ecbdata);
725         }
726         ecbdata.lno_in_preimage = 1;
727         ecbdata.lno_in_postimage = 1;
728
729         lc_a = count_lines(data_one, size_one);
730         lc_b = count_lines(data_two, size_two);
731         fprintf(o->file,
732                 "%s%s--- %s%s%s\n%s%s+++ %s%s%s\n%s%s@@ -",
733                 line_prefix, metainfo, a_name.buf, name_a_tab, reset,
734                 line_prefix, metainfo, b_name.buf, name_b_tab, reset,
735                 line_prefix, fraginfo);
736         if (!o->irreversible_delete)
737                 print_line_count(o->file, lc_a);
738         else
739                 fprintf(o->file, "?,?");
740         fprintf(o->file, " +");
741         print_line_count(o->file, lc_b);
742         fprintf(o->file, " @@%s\n", reset);
743         if (lc_a && !o->irreversible_delete)
744                 emit_rewrite_lines(&ecbdata, '-', data_one, size_one);
745         if (lc_b)
746                 emit_rewrite_lines(&ecbdata, '+', data_two, size_two);
747         if (textconv_one)
748                 free((char *)data_one);
749         if (textconv_two)
750                 free((char *)data_two);
751 }
752
753 struct diff_words_buffer {
754         mmfile_t text;
755         long alloc;
756         struct diff_words_orig {
757                 const char *begin, *end;
758         } *orig;
759         int orig_nr, orig_alloc;
760 };
761
762 static void diff_words_append(char *line, unsigned long len,
763                 struct diff_words_buffer *buffer)
764 {
765         ALLOC_GROW(buffer->text.ptr, buffer->text.size + len, buffer->alloc);
766         line++;
767         len--;
768         memcpy(buffer->text.ptr + buffer->text.size, line, len);
769         buffer->text.size += len;
770         buffer->text.ptr[buffer->text.size] = '\0';
771 }
772
773 struct diff_words_style_elem {
774         const char *prefix;
775         const char *suffix;
776         const char *color; /* NULL; filled in by the setup code if
777                             * color is enabled */
778 };
779
780 struct diff_words_style {
781         enum diff_words_type type;
782         struct diff_words_style_elem new, old, ctx;
783         const char *newline;
784 };
785
786 static struct diff_words_style diff_words_styles[] = {
787         { DIFF_WORDS_PORCELAIN, {"+", "\n"}, {"-", "\n"}, {" ", "\n"}, "~\n" },
788         { DIFF_WORDS_PLAIN, {"{+", "+}"}, {"[-", "-]"}, {"", ""}, "\n" },
789         { DIFF_WORDS_COLOR, {"", ""}, {"", ""}, {"", ""}, "\n" }
790 };
791
792 struct diff_words_data {
793         struct diff_words_buffer minus, plus;
794         const char *current_plus;
795         int last_minus;
796         struct diff_options *opt;
797         regex_t *word_regex;
798         enum diff_words_type type;
799         struct diff_words_style *style;
800 };
801
802 static int fn_out_diff_words_write_helper(FILE *fp,
803                                           struct diff_words_style_elem *st_el,
804                                           const char *newline,
805                                           size_t count, const char *buf,
806                                           const char *line_prefix)
807 {
808         int print = 0;
809
810         while (count) {
811                 char *p = memchr(buf, '\n', count);
812                 if (print)
813                         fputs(line_prefix, fp);
814                 if (p != buf) {
815                         if (st_el->color && fputs(st_el->color, fp) < 0)
816                                 return -1;
817                         if (fputs(st_el->prefix, fp) < 0 ||
818                             fwrite(buf, p ? p - buf : count, 1, fp) != 1 ||
819                             fputs(st_el->suffix, fp) < 0)
820                                 return -1;
821                         if (st_el->color && *st_el->color
822                             && fputs(GIT_COLOR_RESET, fp) < 0)
823                                 return -1;
824                 }
825                 if (!p)
826                         return 0;
827                 if (fputs(newline, fp) < 0)
828                         return -1;
829                 count -= p + 1 - buf;
830                 buf = p + 1;
831                 print = 1;
832         }
833         return 0;
834 }
835
836 /*
837  * '--color-words' algorithm can be described as:
838  *
839  *   1. collect a the minus/plus lines of a diff hunk, divided into
840  *      minus-lines and plus-lines;
841  *
842  *   2. break both minus-lines and plus-lines into words and
843  *      place them into two mmfile_t with one word for each line;
844  *
845  *   3. use xdiff to run diff on the two mmfile_t to get the words level diff;
846  *
847  * And for the common parts of the both file, we output the plus side text.
848  * diff_words->current_plus is used to trace the current position of the plus file
849  * which printed. diff_words->last_minus is used to trace the last minus word
850  * printed.
851  *
852  * For '--graph' to work with '--color-words', we need to output the graph prefix
853  * on each line of color words output. Generally, there are two conditions on
854  * which we should output the prefix.
855  *
856  *   1. diff_words->last_minus == 0 &&
857  *      diff_words->current_plus == diff_words->plus.text.ptr
858  *
859  *      that is: the plus text must start as a new line, and if there is no minus
860  *      word printed, a graph prefix must be printed.
861  *
862  *   2. diff_words->current_plus > diff_words->plus.text.ptr &&
863  *      *(diff_words->current_plus - 1) == '\n'
864  *
865  *      that is: a graph prefix must be printed following a '\n'
866  */
867 static int color_words_output_graph_prefix(struct diff_words_data *diff_words)
868 {
869         if ((diff_words->last_minus == 0 &&
870                 diff_words->current_plus == diff_words->plus.text.ptr) ||
871                 (diff_words->current_plus > diff_words->plus.text.ptr &&
872                 *(diff_words->current_plus - 1) == '\n')) {
873                 return 1;
874         } else {
875                 return 0;
876         }
877 }
878
879 static void fn_out_diff_words_aux(void *priv, char *line, unsigned long len)
880 {
881         struct diff_words_data *diff_words = priv;
882         struct diff_words_style *style = diff_words->style;
883         int minus_first, minus_len, plus_first, plus_len;
884         const char *minus_begin, *minus_end, *plus_begin, *plus_end;
885         struct diff_options *opt = diff_words->opt;
886         const char *line_prefix;
887
888         if (line[0] != '@' || parse_hunk_header(line, len,
889                         &minus_first, &minus_len, &plus_first, &plus_len))
890                 return;
891
892         assert(opt);
893         line_prefix = diff_line_prefix(opt);
894
895         /* POSIX requires that first be decremented by one if len == 0... */
896         if (minus_len) {
897                 minus_begin = diff_words->minus.orig[minus_first].begin;
898                 minus_end =
899                         diff_words->minus.orig[minus_first + minus_len - 1].end;
900         } else
901                 minus_begin = minus_end =
902                         diff_words->minus.orig[minus_first].end;
903
904         if (plus_len) {
905                 plus_begin = diff_words->plus.orig[plus_first].begin;
906                 plus_end = diff_words->plus.orig[plus_first + plus_len - 1].end;
907         } else
908                 plus_begin = plus_end = diff_words->plus.orig[plus_first].end;
909
910         if (color_words_output_graph_prefix(diff_words)) {
911                 fputs(line_prefix, diff_words->opt->file);
912         }
913         if (diff_words->current_plus != plus_begin) {
914                 fn_out_diff_words_write_helper(diff_words->opt->file,
915                                 &style->ctx, style->newline,
916                                 plus_begin - diff_words->current_plus,
917                                 diff_words->current_plus, line_prefix);
918                 if (*(plus_begin - 1) == '\n')
919                         fputs(line_prefix, diff_words->opt->file);
920         }
921         if (minus_begin != minus_end) {
922                 fn_out_diff_words_write_helper(diff_words->opt->file,
923                                 &style->old, style->newline,
924                                 minus_end - minus_begin, minus_begin,
925                                 line_prefix);
926         }
927         if (plus_begin != plus_end) {
928                 fn_out_diff_words_write_helper(diff_words->opt->file,
929                                 &style->new, style->newline,
930                                 plus_end - plus_begin, plus_begin,
931                                 line_prefix);
932         }
933
934         diff_words->current_plus = plus_end;
935         diff_words->last_minus = minus_first;
936 }
937
938 /* This function starts looking at *begin, and returns 0 iff a word was found. */
939 static int find_word_boundaries(mmfile_t *buffer, regex_t *word_regex,
940                 int *begin, int *end)
941 {
942         if (word_regex && *begin < buffer->size) {
943                 regmatch_t match[1];
944                 if (!regexec(word_regex, buffer->ptr + *begin, 1, match, 0)) {
945                         char *p = memchr(buffer->ptr + *begin + match[0].rm_so,
946                                         '\n', match[0].rm_eo - match[0].rm_so);
947                         *end = p ? p - buffer->ptr : match[0].rm_eo + *begin;
948                         *begin += match[0].rm_so;
949                         return *begin >= *end;
950                 }
951                 return -1;
952         }
953
954         /* find the next word */
955         while (*begin < buffer->size && isspace(buffer->ptr[*begin]))
956                 (*begin)++;
957         if (*begin >= buffer->size)
958                 return -1;
959
960         /* find the end of the word */
961         *end = *begin + 1;
962         while (*end < buffer->size && !isspace(buffer->ptr[*end]))
963                 (*end)++;
964
965         return 0;
966 }
967
968 /*
969  * This function splits the words in buffer->text, stores the list with
970  * newline separator into out, and saves the offsets of the original words
971  * in buffer->orig.
972  */
973 static void diff_words_fill(struct diff_words_buffer *buffer, mmfile_t *out,
974                 regex_t *word_regex)
975 {
976         int i, j;
977         long alloc = 0;
978
979         out->size = 0;
980         out->ptr = NULL;
981
982         /* fake an empty "0th" word */
983         ALLOC_GROW(buffer->orig, 1, buffer->orig_alloc);
984         buffer->orig[0].begin = buffer->orig[0].end = buffer->text.ptr;
985         buffer->orig_nr = 1;
986
987         for (i = 0; i < buffer->text.size; i++) {
988                 if (find_word_boundaries(&buffer->text, word_regex, &i, &j))
989                         return;
990
991                 /* store original boundaries */
992                 ALLOC_GROW(buffer->orig, buffer->orig_nr + 1,
993                                 buffer->orig_alloc);
994                 buffer->orig[buffer->orig_nr].begin = buffer->text.ptr + i;
995                 buffer->orig[buffer->orig_nr].end = buffer->text.ptr + j;
996                 buffer->orig_nr++;
997
998                 /* store one word */
999                 ALLOC_GROW(out->ptr, out->size + j - i + 1, alloc);
1000                 memcpy(out->ptr + out->size, buffer->text.ptr + i, j - i);
1001                 out->ptr[out->size + j - i] = '\n';
1002                 out->size += j - i + 1;
1003
1004                 i = j - 1;
1005         }
1006 }
1007
1008 /* this executes the word diff on the accumulated buffers */
1009 static void diff_words_show(struct diff_words_data *diff_words)
1010 {
1011         xpparam_t xpp;
1012         xdemitconf_t xecfg;
1013         mmfile_t minus, plus;
1014         struct diff_words_style *style = diff_words->style;
1015
1016         struct diff_options *opt = diff_words->opt;
1017         const char *line_prefix;
1018
1019         assert(opt);
1020         line_prefix = diff_line_prefix(opt);
1021
1022         /* special case: only removal */
1023         if (!diff_words->plus.text.size) {
1024                 fputs(line_prefix, diff_words->opt->file);
1025                 fn_out_diff_words_write_helper(diff_words->opt->file,
1026                         &style->old, style->newline,
1027                         diff_words->minus.text.size,
1028                         diff_words->minus.text.ptr, line_prefix);
1029                 diff_words->minus.text.size = 0;
1030                 return;
1031         }
1032
1033         diff_words->current_plus = diff_words->plus.text.ptr;
1034         diff_words->last_minus = 0;
1035
1036         memset(&xpp, 0, sizeof(xpp));
1037         memset(&xecfg, 0, sizeof(xecfg));
1038         diff_words_fill(&diff_words->minus, &minus, diff_words->word_regex);
1039         diff_words_fill(&diff_words->plus, &plus, diff_words->word_regex);
1040         xpp.flags = 0;
1041         /* as only the hunk header will be parsed, we need a 0-context */
1042         xecfg.ctxlen = 0;
1043         if (xdi_diff_outf(&minus, &plus, fn_out_diff_words_aux, diff_words,
1044                           &xpp, &xecfg))
1045                 die("unable to generate word diff");
1046         free(minus.ptr);
1047         free(plus.ptr);
1048         if (diff_words->current_plus != diff_words->plus.text.ptr +
1049                         diff_words->plus.text.size) {
1050                 if (color_words_output_graph_prefix(diff_words))
1051                         fputs(line_prefix, diff_words->opt->file);
1052                 fn_out_diff_words_write_helper(diff_words->opt->file,
1053                         &style->ctx, style->newline,
1054                         diff_words->plus.text.ptr + diff_words->plus.text.size
1055                         - diff_words->current_plus, diff_words->current_plus,
1056                         line_prefix);
1057         }
1058         diff_words->minus.text.size = diff_words->plus.text.size = 0;
1059 }
1060
1061 /* In "color-words" mode, show word-diff of words accumulated in the buffer */
1062 static void diff_words_flush(struct emit_callback *ecbdata)
1063 {
1064         if (ecbdata->diff_words->minus.text.size ||
1065             ecbdata->diff_words->plus.text.size)
1066                 diff_words_show(ecbdata->diff_words);
1067 }
1068
1069 static void diff_filespec_load_driver(struct diff_filespec *one)
1070 {
1071         /* Use already-loaded driver */
1072         if (one->driver)
1073                 return;
1074
1075         if (S_ISREG(one->mode))
1076                 one->driver = userdiff_find_by_path(one->path);
1077
1078         /* Fallback to default settings */
1079         if (!one->driver)
1080                 one->driver = userdiff_find_by_name("default");
1081 }
1082
1083 static const char *userdiff_word_regex(struct diff_filespec *one)
1084 {
1085         diff_filespec_load_driver(one);
1086         return one->driver->word_regex;
1087 }
1088
1089 static void init_diff_words_data(struct emit_callback *ecbdata,
1090                                  struct diff_options *orig_opts,
1091                                  struct diff_filespec *one,
1092                                  struct diff_filespec *two)
1093 {
1094         int i;
1095         struct diff_options *o = xmalloc(sizeof(struct diff_options));
1096         memcpy(o, orig_opts, sizeof(struct diff_options));
1097
1098         ecbdata->diff_words =
1099                 xcalloc(1, sizeof(struct diff_words_data));
1100         ecbdata->diff_words->type = o->word_diff;
1101         ecbdata->diff_words->opt = o;
1102         if (!o->word_regex)
1103                 o->word_regex = userdiff_word_regex(one);
1104         if (!o->word_regex)
1105                 o->word_regex = userdiff_word_regex(two);
1106         if (!o->word_regex)
1107                 o->word_regex = diff_word_regex_cfg;
1108         if (o->word_regex) {
1109                 ecbdata->diff_words->word_regex = (regex_t *)
1110                         xmalloc(sizeof(regex_t));
1111                 if (regcomp(ecbdata->diff_words->word_regex,
1112                             o->word_regex,
1113                             REG_EXTENDED | REG_NEWLINE))
1114                         die ("Invalid regular expression: %s",
1115                              o->word_regex);
1116         }
1117         for (i = 0; i < ARRAY_SIZE(diff_words_styles); i++) {
1118                 if (o->word_diff == diff_words_styles[i].type) {
1119                         ecbdata->diff_words->style =
1120                                 &diff_words_styles[i];
1121                         break;
1122                 }
1123         }
1124         if (want_color(o->use_color)) {
1125                 struct diff_words_style *st = ecbdata->diff_words->style;
1126                 st->old.color = diff_get_color_opt(o, DIFF_FILE_OLD);
1127                 st->new.color = diff_get_color_opt(o, DIFF_FILE_NEW);
1128                 st->ctx.color = diff_get_color_opt(o, DIFF_CONTEXT);
1129         }
1130 }
1131
1132 static void free_diff_words_data(struct emit_callback *ecbdata)
1133 {
1134         if (ecbdata->diff_words) {
1135                 diff_words_flush(ecbdata);
1136                 free (ecbdata->diff_words->opt);
1137                 free (ecbdata->diff_words->minus.text.ptr);
1138                 free (ecbdata->diff_words->minus.orig);
1139                 free (ecbdata->diff_words->plus.text.ptr);
1140                 free (ecbdata->diff_words->plus.orig);
1141                 if (ecbdata->diff_words->word_regex) {
1142                         regfree(ecbdata->diff_words->word_regex);
1143                         free(ecbdata->diff_words->word_regex);
1144                 }
1145                 free(ecbdata->diff_words);
1146                 ecbdata->diff_words = NULL;
1147         }
1148 }
1149
1150 const char *diff_get_color(int diff_use_color, enum color_diff ix)
1151 {
1152         if (want_color(diff_use_color))
1153                 return diff_colors[ix];
1154         return "";
1155 }
1156
1157 const char *diff_line_prefix(struct diff_options *opt)
1158 {
1159         struct strbuf *msgbuf;
1160         if (!opt->output_prefix)
1161                 return "";
1162
1163         msgbuf = opt->output_prefix(opt, opt->output_prefix_data);
1164         return msgbuf->buf;
1165 }
1166
1167 static unsigned long sane_truncate_line(struct emit_callback *ecb, char *line, unsigned long len)
1168 {
1169         const char *cp;
1170         unsigned long allot;
1171         size_t l = len;
1172
1173         if (ecb->truncate)
1174                 return ecb->truncate(line, len);
1175         cp = line;
1176         allot = l;
1177         while (0 < l) {
1178                 (void) utf8_width(&cp, &l);
1179                 if (!cp)
1180                         break; /* truncated in the middle? */
1181         }
1182         return allot - l;
1183 }
1184
1185 static void find_lno(const char *line, struct emit_callback *ecbdata)
1186 {
1187         const char *p;
1188         ecbdata->lno_in_preimage = 0;
1189         ecbdata->lno_in_postimage = 0;
1190         p = strchr(line, '-');
1191         if (!p)
1192                 return; /* cannot happen */
1193         ecbdata->lno_in_preimage = strtol(p + 1, NULL, 10);
1194         p = strchr(p, '+');
1195         if (!p)
1196                 return; /* cannot happen */
1197         ecbdata->lno_in_postimage = strtol(p + 1, NULL, 10);
1198 }
1199
1200 static void fn_out_consume(void *priv, char *line, unsigned long len)
1201 {
1202         struct emit_callback *ecbdata = priv;
1203         const char *meta = diff_get_color(ecbdata->color_diff, DIFF_METAINFO);
1204         const char *context = diff_get_color(ecbdata->color_diff, DIFF_CONTEXT);
1205         const char *reset = diff_get_color(ecbdata->color_diff, DIFF_RESET);
1206         struct diff_options *o = ecbdata->opt;
1207         const char *line_prefix = diff_line_prefix(o);
1208
1209         if (ecbdata->header) {
1210                 fprintf(ecbdata->opt->file, "%s", ecbdata->header->buf);
1211                 strbuf_reset(ecbdata->header);
1212                 ecbdata->header = NULL;
1213         }
1214         *(ecbdata->found_changesp) = 1;
1215
1216         if (ecbdata->label_path[0]) {
1217                 const char *name_a_tab, *name_b_tab;
1218
1219                 name_a_tab = strchr(ecbdata->label_path[0], ' ') ? "\t" : "";
1220                 name_b_tab = strchr(ecbdata->label_path[1], ' ') ? "\t" : "";
1221
1222                 fprintf(ecbdata->opt->file, "%s%s--- %s%s%s\n",
1223                         line_prefix, meta, ecbdata->label_path[0], reset, name_a_tab);
1224                 fprintf(ecbdata->opt->file, "%s%s+++ %s%s%s\n",
1225                         line_prefix, meta, ecbdata->label_path[1], reset, name_b_tab);
1226                 ecbdata->label_path[0] = ecbdata->label_path[1] = NULL;
1227         }
1228
1229         if (diff_suppress_blank_empty
1230             && len == 2 && line[0] == ' ' && line[1] == '\n') {
1231                 line[0] = '\n';
1232                 len = 1;
1233         }
1234
1235         if (line[0] == '@') {
1236                 if (ecbdata->diff_words)
1237                         diff_words_flush(ecbdata);
1238                 len = sane_truncate_line(ecbdata, line, len);
1239                 find_lno(line, ecbdata);
1240                 emit_hunk_header(ecbdata, line, len);
1241                 if (line[len-1] != '\n')
1242                         putc('\n', ecbdata->opt->file);
1243                 return;
1244         }
1245
1246         if (len < 1) {
1247                 emit_line(ecbdata->opt, reset, reset, line, len);
1248                 if (ecbdata->diff_words
1249                     && ecbdata->diff_words->type == DIFF_WORDS_PORCELAIN)
1250                         fputs("~\n", ecbdata->opt->file);
1251                 return;
1252         }
1253
1254         if (ecbdata->diff_words) {
1255                 if (line[0] == '-') {
1256                         diff_words_append(line, len,
1257                                           &ecbdata->diff_words->minus);
1258                         return;
1259                 } else if (line[0] == '+') {
1260                         diff_words_append(line, len,
1261                                           &ecbdata->diff_words->plus);
1262                         return;
1263                 } else if (starts_with(line, "\\ ")) {
1264                         /*
1265                          * Eat the "no newline at eof" marker as if we
1266                          * saw a "+" or "-" line with nothing on it,
1267                          * and return without diff_words_flush() to
1268                          * defer processing. If this is the end of
1269                          * preimage, more "+" lines may come after it.
1270                          */
1271                         return;
1272                 }
1273                 diff_words_flush(ecbdata);
1274                 if (ecbdata->diff_words->type == DIFF_WORDS_PORCELAIN) {
1275                         emit_line(ecbdata->opt, context, reset, line, len);
1276                         fputs("~\n", ecbdata->opt->file);
1277                 } else {
1278                         /*
1279                          * Skip the prefix character, if any.  With
1280                          * diff_suppress_blank_empty, there may be
1281                          * none.
1282                          */
1283                         if (line[0] != '\n') {
1284                               line++;
1285                               len--;
1286                         }
1287                         emit_line(ecbdata->opt, context, reset, line, len);
1288                 }
1289                 return;
1290         }
1291
1292         switch (line[0]) {
1293         case '+':
1294                 ecbdata->lno_in_postimage++;
1295                 emit_add_line(reset, ecbdata, line + 1, len - 1);
1296                 break;
1297         case '-':
1298                 ecbdata->lno_in_preimage++;
1299                 emit_del_line(reset, ecbdata, line + 1, len - 1);
1300                 break;
1301         case ' ':
1302                 ecbdata->lno_in_postimage++;
1303                 ecbdata->lno_in_preimage++;
1304                 emit_context_line(reset, ecbdata, line + 1, len - 1);
1305                 break;
1306         default:
1307                 /* incomplete line at the end */
1308                 ecbdata->lno_in_preimage++;
1309                 emit_line(ecbdata->opt,
1310                           diff_get_color(ecbdata->color_diff, DIFF_CONTEXT),
1311                           reset, line, len);
1312                 break;
1313         }
1314 }
1315
1316 static char *pprint_rename(const char *a, const char *b)
1317 {
1318         const char *old = a;
1319         const char *new = b;
1320         struct strbuf name = STRBUF_INIT;
1321         int pfx_length, sfx_length;
1322         int pfx_adjust_for_slash;
1323         int len_a = strlen(a);
1324         int len_b = strlen(b);
1325         int a_midlen, b_midlen;
1326         int qlen_a = quote_c_style(a, NULL, NULL, 0);
1327         int qlen_b = quote_c_style(b, NULL, NULL, 0);
1328
1329         if (qlen_a || qlen_b) {
1330                 quote_c_style(a, &name, NULL, 0);
1331                 strbuf_addstr(&name, " => ");
1332                 quote_c_style(b, &name, NULL, 0);
1333                 return strbuf_detach(&name, NULL);
1334         }
1335
1336         /* Find common prefix */
1337         pfx_length = 0;
1338         while (*old && *new && *old == *new) {
1339                 if (*old == '/')
1340                         pfx_length = old - a + 1;
1341                 old++;
1342                 new++;
1343         }
1344
1345         /* Find common suffix */
1346         old = a + len_a;
1347         new = b + len_b;
1348         sfx_length = 0;
1349         /*
1350          * If there is a common prefix, it must end in a slash.  In
1351          * that case we let this loop run 1 into the prefix to see the
1352          * same slash.
1353          *
1354          * If there is no common prefix, we cannot do this as it would
1355          * underrun the input strings.
1356          */
1357         pfx_adjust_for_slash = (pfx_length ? 1 : 0);
1358         while (a + pfx_length - pfx_adjust_for_slash <= old &&
1359                b + pfx_length - pfx_adjust_for_slash <= new &&
1360                *old == *new) {
1361                 if (*old == '/')
1362                         sfx_length = len_a - (old - a);
1363                 old--;
1364                 new--;
1365         }
1366
1367         /*
1368          * pfx{mid-a => mid-b}sfx
1369          * {pfx-a => pfx-b}sfx
1370          * pfx{sfx-a => sfx-b}
1371          * name-a => name-b
1372          */
1373         a_midlen = len_a - pfx_length - sfx_length;
1374         b_midlen = len_b - pfx_length - sfx_length;
1375         if (a_midlen < 0)
1376                 a_midlen = 0;
1377         if (b_midlen < 0)
1378                 b_midlen = 0;
1379
1380         strbuf_grow(&name, pfx_length + a_midlen + b_midlen + sfx_length + 7);
1381         if (pfx_length + sfx_length) {
1382                 strbuf_add(&name, a, pfx_length);
1383                 strbuf_addch(&name, '{');
1384         }
1385         strbuf_add(&name, a + pfx_length, a_midlen);
1386         strbuf_addstr(&name, " => ");
1387         strbuf_add(&name, b + pfx_length, b_midlen);
1388         if (pfx_length + sfx_length) {
1389                 strbuf_addch(&name, '}');
1390                 strbuf_add(&name, a + len_a - sfx_length, sfx_length);
1391         }
1392         return strbuf_detach(&name, NULL);
1393 }
1394
1395 struct diffstat_t {
1396         int nr;
1397         int alloc;
1398         struct diffstat_file {
1399                 char *from_name;
1400                 char *name;
1401                 char *print_name;
1402                 unsigned is_unmerged:1;
1403                 unsigned is_binary:1;
1404                 unsigned is_renamed:1;
1405                 unsigned is_interesting:1;
1406                 uintmax_t added, deleted;
1407         } **files;
1408 };
1409
1410 static struct diffstat_file *diffstat_add(struct diffstat_t *diffstat,
1411                                           const char *name_a,
1412                                           const char *name_b)
1413 {
1414         struct diffstat_file *x;
1415         x = xcalloc(1, sizeof(*x));
1416         ALLOC_GROW(diffstat->files, diffstat->nr + 1, diffstat->alloc);
1417         diffstat->files[diffstat->nr++] = x;
1418         if (name_b) {
1419                 x->from_name = xstrdup(name_a);
1420                 x->name = xstrdup(name_b);
1421                 x->is_renamed = 1;
1422         }
1423         else {
1424                 x->from_name = NULL;
1425                 x->name = xstrdup(name_a);
1426         }
1427         return x;
1428 }
1429
1430 static void diffstat_consume(void *priv, char *line, unsigned long len)
1431 {
1432         struct diffstat_t *diffstat = priv;
1433         struct diffstat_file *x = diffstat->files[diffstat->nr - 1];
1434
1435         if (line[0] == '+')
1436                 x->added++;
1437         else if (line[0] == '-')
1438                 x->deleted++;
1439 }
1440
1441 const char mime_boundary_leader[] = "------------";
1442
1443 static int scale_linear(int it, int width, int max_change)
1444 {
1445         if (!it)
1446                 return 0;
1447         /*
1448          * make sure that at least one '-' or '+' is printed if
1449          * there is any change to this path. The easiest way is to
1450          * scale linearly as if the alloted width is one column shorter
1451          * than it is, and then add 1 to the result.
1452          */
1453         return 1 + (it * (width - 1) / max_change);
1454 }
1455
1456 static void show_name(FILE *file,
1457                       const char *prefix, const char *name, int len)
1458 {
1459         fprintf(file, " %s%-*s |", prefix, len, name);
1460 }
1461
1462 static void show_graph(FILE *file, char ch, int cnt, const char *set, const char *reset)
1463 {
1464         if (cnt <= 0)
1465                 return;
1466         fprintf(file, "%s", set);
1467         while (cnt--)
1468                 putc(ch, file);
1469         fprintf(file, "%s", reset);
1470 }
1471
1472 static void fill_print_name(struct diffstat_file *file)
1473 {
1474         char *pname;
1475
1476         if (file->print_name)
1477                 return;
1478
1479         if (!file->is_renamed) {
1480                 struct strbuf buf = STRBUF_INIT;
1481                 if (quote_c_style(file->name, &buf, NULL, 0)) {
1482                         pname = strbuf_detach(&buf, NULL);
1483                 } else {
1484                         pname = file->name;
1485                         strbuf_release(&buf);
1486                 }
1487         } else {
1488                 pname = pprint_rename(file->from_name, file->name);
1489         }
1490         file->print_name = pname;
1491 }
1492
1493 int print_stat_summary(FILE *fp, int files, int insertions, int deletions)
1494 {
1495         struct strbuf sb = STRBUF_INIT;
1496         int ret;
1497
1498         if (!files) {
1499                 assert(insertions == 0 && deletions == 0);
1500                 return fprintf(fp, "%s\n", " 0 files changed");
1501         }
1502
1503         strbuf_addf(&sb,
1504                     (files == 1) ? " %d file changed" : " %d files changed",
1505                     files);
1506
1507         /*
1508          * For binary diff, the caller may want to print "x files
1509          * changed" with insertions == 0 && deletions == 0.
1510          *
1511          * Not omitting "0 insertions(+), 0 deletions(-)" in this case
1512          * is probably less confusing (i.e skip over "2 files changed
1513          * but nothing about added/removed lines? Is this a bug in Git?").
1514          */
1515         if (insertions || deletions == 0) {
1516                 strbuf_addf(&sb,
1517                             (insertions == 1) ? ", %d insertion(+)" : ", %d insertions(+)",
1518                             insertions);
1519         }
1520
1521         if (deletions || insertions == 0) {
1522                 strbuf_addf(&sb,
1523                             (deletions == 1) ? ", %d deletion(-)" : ", %d deletions(-)",
1524                             deletions);
1525         }
1526         strbuf_addch(&sb, '\n');
1527         ret = fputs(sb.buf, fp);
1528         strbuf_release(&sb);
1529         return ret;
1530 }
1531
1532 static void show_stats(struct diffstat_t *data, struct diff_options *options)
1533 {
1534         int i, len, add, del, adds = 0, dels = 0;
1535         uintmax_t max_change = 0, max_len = 0;
1536         int total_files = data->nr, count;
1537         int width, name_width, graph_width, number_width = 0, bin_width = 0;
1538         const char *reset, *add_c, *del_c;
1539         const char *line_prefix = "";
1540         int extra_shown = 0;
1541
1542         if (data->nr == 0)
1543                 return;
1544
1545         line_prefix = diff_line_prefix(options);
1546         count = options->stat_count ? options->stat_count : data->nr;
1547
1548         reset = diff_get_color_opt(options, DIFF_RESET);
1549         add_c = diff_get_color_opt(options, DIFF_FILE_NEW);
1550         del_c = diff_get_color_opt(options, DIFF_FILE_OLD);
1551
1552         /*
1553          * Find the longest filename and max number of changes
1554          */
1555         for (i = 0; (i < count) && (i < data->nr); i++) {
1556                 struct diffstat_file *file = data->files[i];
1557                 uintmax_t change = file->added + file->deleted;
1558
1559                 if (!file->is_interesting && (change == 0)) {
1560                         count++; /* not shown == room for one more */
1561                         continue;
1562                 }
1563                 fill_print_name(file);
1564                 len = strlen(file->print_name);
1565                 if (max_len < len)
1566                         max_len = len;
1567
1568                 if (file->is_unmerged) {
1569                         /* "Unmerged" is 8 characters */
1570                         bin_width = bin_width < 8 ? 8 : bin_width;
1571                         continue;
1572                 }
1573                 if (file->is_binary) {
1574                         /* "Bin XXX -> YYY bytes" */
1575                         int w = 14 + decimal_width(file->added)
1576                                 + decimal_width(file->deleted);
1577                         bin_width = bin_width < w ? w : bin_width;
1578                         /* Display change counts aligned with "Bin" */
1579                         number_width = 3;
1580                         continue;
1581                 }
1582
1583                 if (max_change < change)
1584                         max_change = change;
1585         }
1586         count = i; /* where we can stop scanning in data->files[] */
1587
1588         /*
1589          * We have width = stat_width or term_columns() columns total.
1590          * We want a maximum of min(max_len, stat_name_width) for the name part.
1591          * We want a maximum of min(max_change, stat_graph_width) for the +- part.
1592          * We also need 1 for " " and 4 + decimal_width(max_change)
1593          * for " | NNNN " and one the empty column at the end, altogether
1594          * 6 + decimal_width(max_change).
1595          *
1596          * If there's not enough space, we will use the smaller of
1597          * stat_name_width (if set) and 5/8*width for the filename,
1598          * and the rest for constant elements + graph part, but no more
1599          * than stat_graph_width for the graph part.
1600          * (5/8 gives 50 for filename and 30 for the constant parts + graph
1601          * for the standard terminal size).
1602          *
1603          * In other words: stat_width limits the maximum width, and
1604          * stat_name_width fixes the maximum width of the filename,
1605          * and is also used to divide available columns if there
1606          * aren't enough.
1607          *
1608          * Binary files are displayed with "Bin XXX -> YYY bytes"
1609          * instead of the change count and graph. This part is treated
1610          * similarly to the graph part, except that it is not
1611          * "scaled". If total width is too small to accommodate the
1612          * guaranteed minimum width of the filename part and the
1613          * separators and this message, this message will "overflow"
1614          * making the line longer than the maximum width.
1615          */
1616
1617         if (options->stat_width == -1)
1618                 width = term_columns() - options->output_prefix_length;
1619         else
1620                 width = options->stat_width ? options->stat_width : 80;
1621         number_width = decimal_width(max_change) > number_width ?
1622                 decimal_width(max_change) : number_width;
1623
1624         if (options->stat_graph_width == -1)
1625                 options->stat_graph_width = diff_stat_graph_width;
1626
1627         /*
1628          * Guarantee 3/8*16==6 for the graph part
1629          * and 5/8*16==10 for the filename part
1630          */
1631         if (width < 16 + 6 + number_width)
1632                 width = 16 + 6 + number_width;
1633
1634         /*
1635          * First assign sizes that are wanted, ignoring available width.
1636          * strlen("Bin XXX -> YYY bytes") == bin_width, and the part
1637          * starting from "XXX" should fit in graph_width.
1638          */
1639         graph_width = max_change + 4 > bin_width ? max_change : bin_width - 4;
1640         if (options->stat_graph_width &&
1641             options->stat_graph_width < graph_width)
1642                 graph_width = options->stat_graph_width;
1643
1644         name_width = (options->stat_name_width > 0 &&
1645                       options->stat_name_width < max_len) ?
1646                 options->stat_name_width : max_len;
1647
1648         /*
1649          * Adjust adjustable widths not to exceed maximum width
1650          */
1651         if (name_width + number_width + 6 + graph_width > width) {
1652                 if (graph_width > width * 3/8 - number_width - 6) {
1653                         graph_width = width * 3/8 - number_width - 6;
1654                         if (graph_width < 6)
1655                                 graph_width = 6;
1656                 }
1657
1658                 if (options->stat_graph_width &&
1659                     graph_width > options->stat_graph_width)
1660                         graph_width = options->stat_graph_width;
1661                 if (name_width > width - number_width - 6 - graph_width)
1662                         name_width = width - number_width - 6 - graph_width;
1663                 else
1664                         graph_width = width - number_width - 6 - name_width;
1665         }
1666
1667         /*
1668          * From here name_width is the width of the name area,
1669          * and graph_width is the width of the graph area.
1670          * max_change is used to scale graph properly.
1671          */
1672         for (i = 0; i < count; i++) {
1673                 const char *prefix = "";
1674                 struct diffstat_file *file = data->files[i];
1675                 char *name = file->print_name;
1676                 uintmax_t added = file->added;
1677                 uintmax_t deleted = file->deleted;
1678                 int name_len;
1679
1680                 if (!file->is_interesting && (added + deleted == 0))
1681                         continue;
1682
1683                 /*
1684                  * "scale" the filename
1685                  */
1686                 len = name_width;
1687                 name_len = strlen(name);
1688                 if (name_width < name_len) {
1689                         char *slash;
1690                         prefix = "...";
1691                         len -= 3;
1692                         name += name_len - len;
1693                         slash = strchr(name, '/');
1694                         if (slash)
1695                                 name = slash;
1696                 }
1697
1698                 if (file->is_binary) {
1699                         fprintf(options->file, "%s", line_prefix);
1700                         show_name(options->file, prefix, name, len);
1701                         fprintf(options->file, " %*s", number_width, "Bin");
1702                         if (!added && !deleted) {
1703                                 putc('\n', options->file);
1704                                 continue;
1705                         }
1706                         fprintf(options->file, " %s%"PRIuMAX"%s",
1707                                 del_c, deleted, reset);
1708                         fprintf(options->file, " -> ");
1709                         fprintf(options->file, "%s%"PRIuMAX"%s",
1710                                 add_c, added, reset);
1711                         fprintf(options->file, " bytes");
1712                         fprintf(options->file, "\n");
1713                         continue;
1714                 }
1715                 else if (file->is_unmerged) {
1716                         fprintf(options->file, "%s", line_prefix);
1717                         show_name(options->file, prefix, name, len);
1718                         fprintf(options->file, " Unmerged\n");
1719                         continue;
1720                 }
1721
1722                 /*
1723                  * scale the add/delete
1724                  */
1725                 add = added;
1726                 del = deleted;
1727
1728                 if (graph_width <= max_change) {
1729                         int total = scale_linear(add + del, graph_width, max_change);
1730                         if (total < 2 && add && del)
1731                                 /* width >= 2 due to the sanity check */
1732                                 total = 2;
1733                         if (add < del) {
1734                                 add = scale_linear(add, graph_width, max_change);
1735                                 del = total - add;
1736                         } else {
1737                                 del = scale_linear(del, graph_width, max_change);
1738                                 add = total - del;
1739                         }
1740                 }
1741                 fprintf(options->file, "%s", line_prefix);
1742                 show_name(options->file, prefix, name, len);
1743                 fprintf(options->file, " %*"PRIuMAX"%s",
1744                         number_width, added + deleted,
1745                         added + deleted ? " " : "");
1746                 show_graph(options->file, '+', add, add_c, reset);
1747                 show_graph(options->file, '-', del, del_c, reset);
1748                 fprintf(options->file, "\n");
1749         }
1750
1751         for (i = 0; i < data->nr; i++) {
1752                 struct diffstat_file *file = data->files[i];
1753                 uintmax_t added = file->added;
1754                 uintmax_t deleted = file->deleted;
1755
1756                 if (file->is_unmerged ||
1757                     (!file->is_interesting && (added + deleted == 0))) {
1758                         total_files--;
1759                         continue;
1760                 }
1761
1762                 if (!file->is_binary) {
1763                         adds += added;
1764                         dels += deleted;
1765                 }
1766                 if (i < count)
1767                         continue;
1768                 if (!extra_shown)
1769                         fprintf(options->file, "%s ...\n", line_prefix);
1770                 extra_shown = 1;
1771         }
1772         fprintf(options->file, "%s", line_prefix);
1773         print_stat_summary(options->file, total_files, adds, dels);
1774 }
1775
1776 static void show_shortstats(struct diffstat_t *data, struct diff_options *options)
1777 {
1778         int i, adds = 0, dels = 0, total_files = data->nr;
1779
1780         if (data->nr == 0)
1781                 return;
1782
1783         for (i = 0; i < data->nr; i++) {
1784                 int added = data->files[i]->added;
1785                 int deleted= data->files[i]->deleted;
1786
1787                 if (data->files[i]->is_unmerged ||
1788                     (!data->files[i]->is_interesting && (added + deleted == 0))) {
1789                         total_files--;
1790                 } else if (!data->files[i]->is_binary) { /* don't count bytes */
1791                         adds += added;
1792                         dels += deleted;
1793                 }
1794         }
1795         fprintf(options->file, "%s", diff_line_prefix(options));
1796         print_stat_summary(options->file, total_files, adds, dels);
1797 }
1798
1799 static void show_numstat(struct diffstat_t *data, struct diff_options *options)
1800 {
1801         int i;
1802
1803         if (data->nr == 0)
1804                 return;
1805
1806         for (i = 0; i < data->nr; i++) {
1807                 struct diffstat_file *file = data->files[i];
1808
1809                 fprintf(options->file, "%s", diff_line_prefix(options));
1810
1811                 if (file->is_binary)
1812                         fprintf(options->file, "-\t-\t");
1813                 else
1814                         fprintf(options->file,
1815                                 "%"PRIuMAX"\t%"PRIuMAX"\t",
1816                                 file->added, file->deleted);
1817                 if (options->line_termination) {
1818                         fill_print_name(file);
1819                         if (!file->is_renamed)
1820                                 write_name_quoted(file->name, options->file,
1821                                                   options->line_termination);
1822                         else {
1823                                 fputs(file->print_name, options->file);
1824                                 putc(options->line_termination, options->file);
1825                         }
1826                 } else {
1827                         if (file->is_renamed) {
1828                                 putc('\0', options->file);
1829                                 write_name_quoted(file->from_name, options->file, '\0');
1830                         }
1831                         write_name_quoted(file->name, options->file, '\0');
1832                 }
1833         }
1834 }
1835
1836 struct dirstat_file {
1837         const char *name;
1838         unsigned long changed;
1839 };
1840
1841 struct dirstat_dir {
1842         struct dirstat_file *files;
1843         int alloc, nr, permille, cumulative;
1844 };
1845
1846 static long gather_dirstat(struct diff_options *opt, struct dirstat_dir *dir,
1847                 unsigned long changed, const char *base, int baselen)
1848 {
1849         unsigned long this_dir = 0;
1850         unsigned int sources = 0;
1851         const char *line_prefix = diff_line_prefix(opt);
1852
1853         while (dir->nr) {
1854                 struct dirstat_file *f = dir->files;
1855                 int namelen = strlen(f->name);
1856                 unsigned long this;
1857                 char *slash;
1858
1859                 if (namelen < baselen)
1860                         break;
1861                 if (memcmp(f->name, base, baselen))
1862                         break;
1863                 slash = strchr(f->name + baselen, '/');
1864                 if (slash) {
1865                         int newbaselen = slash + 1 - f->name;
1866                         this = gather_dirstat(opt, dir, changed, f->name, newbaselen);
1867                         sources++;
1868                 } else {
1869                         this = f->changed;
1870                         dir->files++;
1871                         dir->nr--;
1872                         sources += 2;
1873                 }
1874                 this_dir += this;
1875         }
1876
1877         /*
1878          * We don't report dirstat's for
1879          *  - the top level
1880          *  - or cases where everything came from a single directory
1881          *    under this directory (sources == 1).
1882          */
1883         if (baselen && sources != 1) {
1884                 if (this_dir) {
1885                         int permille = this_dir * 1000 / changed;
1886                         if (permille >= dir->permille) {
1887                                 fprintf(opt->file, "%s%4d.%01d%% %.*s\n", line_prefix,
1888                                         permille / 10, permille % 10, baselen, base);
1889                                 if (!dir->cumulative)
1890                                         return 0;
1891                         }
1892                 }
1893         }
1894         return this_dir;
1895 }
1896
1897 static int dirstat_compare(const void *_a, const void *_b)
1898 {
1899         const struct dirstat_file *a = _a;
1900         const struct dirstat_file *b = _b;
1901         return strcmp(a->name, b->name);
1902 }
1903
1904 static void show_dirstat(struct diff_options *options)
1905 {
1906         int i;
1907         unsigned long changed;
1908         struct dirstat_dir dir;
1909         struct diff_queue_struct *q = &diff_queued_diff;
1910
1911         dir.files = NULL;
1912         dir.alloc = 0;
1913         dir.nr = 0;
1914         dir.permille = options->dirstat_permille;
1915         dir.cumulative = DIFF_OPT_TST(options, DIRSTAT_CUMULATIVE);
1916
1917         changed = 0;
1918         for (i = 0; i < q->nr; i++) {
1919                 struct diff_filepair *p = q->queue[i];
1920                 const char *name;
1921                 unsigned long copied, added, damage;
1922                 int content_changed;
1923
1924                 name = p->two->path ? p->two->path : p->one->path;
1925
1926                 if (p->one->sha1_valid && p->two->sha1_valid)
1927                         content_changed = hashcmp(p->one->sha1, p->two->sha1);
1928                 else
1929                         content_changed = 1;
1930
1931                 if (!content_changed) {
1932                         /*
1933                          * The SHA1 has not changed, so pre-/post-content is
1934                          * identical. We can therefore skip looking at the
1935                          * file contents altogether.
1936                          */
1937                         damage = 0;
1938                         goto found_damage;
1939                 }
1940
1941                 if (DIFF_OPT_TST(options, DIRSTAT_BY_FILE)) {
1942                         /*
1943                          * In --dirstat-by-file mode, we don't really need to
1944                          * look at the actual file contents at all.
1945                          * The fact that the SHA1 changed is enough for us to
1946                          * add this file to the list of results
1947                          * (with each file contributing equal damage).
1948                          */
1949                         damage = 1;
1950                         goto found_damage;
1951                 }
1952
1953                 if (DIFF_FILE_VALID(p->one) && DIFF_FILE_VALID(p->two)) {
1954                         diff_populate_filespec(p->one, 0);
1955                         diff_populate_filespec(p->two, 0);
1956                         diffcore_count_changes(p->one, p->two, NULL, NULL, 0,
1957                                                &copied, &added);
1958                         diff_free_filespec_data(p->one);
1959                         diff_free_filespec_data(p->two);
1960                 } else if (DIFF_FILE_VALID(p->one)) {
1961                         diff_populate_filespec(p->one, CHECK_SIZE_ONLY);
1962                         copied = added = 0;
1963                         diff_free_filespec_data(p->one);
1964                 } else if (DIFF_FILE_VALID(p->two)) {
1965                         diff_populate_filespec(p->two, CHECK_SIZE_ONLY);
1966                         copied = 0;
1967                         added = p->two->size;
1968                         diff_free_filespec_data(p->two);
1969                 } else
1970                         continue;
1971
1972                 /*
1973                  * Original minus copied is the removed material,
1974                  * added is the new material.  They are both damages
1975                  * made to the preimage.
1976                  * If the resulting damage is zero, we know that
1977                  * diffcore_count_changes() considers the two entries to
1978                  * be identical, but since content_changed is true, we
1979                  * know that there must have been _some_ kind of change,
1980                  * so we force all entries to have damage > 0.
1981                  */
1982                 damage = (p->one->size - copied) + added;
1983                 if (!damage)
1984                         damage = 1;
1985
1986 found_damage:
1987                 ALLOC_GROW(dir.files, dir.nr + 1, dir.alloc);
1988                 dir.files[dir.nr].name = name;
1989                 dir.files[dir.nr].changed = damage;
1990                 changed += damage;
1991                 dir.nr++;
1992         }
1993
1994         /* This can happen even with many files, if everything was renames */
1995         if (!changed)
1996                 return;
1997
1998         /* Show all directories with more than x% of the changes */
1999         qsort(dir.files, dir.nr, sizeof(dir.files[0]), dirstat_compare);
2000         gather_dirstat(options, &dir, changed, "", 0);
2001 }
2002
2003 static void show_dirstat_by_line(struct diffstat_t *data, struct diff_options *options)
2004 {
2005         int i;
2006         unsigned long changed;
2007         struct dirstat_dir dir;
2008
2009         if (data->nr == 0)
2010                 return;
2011
2012         dir.files = NULL;
2013         dir.alloc = 0;
2014         dir.nr = 0;
2015         dir.permille = options->dirstat_permille;
2016         dir.cumulative = DIFF_OPT_TST(options, DIRSTAT_CUMULATIVE);
2017
2018         changed = 0;
2019         for (i = 0; i < data->nr; i++) {
2020                 struct diffstat_file *file = data->files[i];
2021                 unsigned long damage = file->added + file->deleted;
2022                 if (file->is_binary)
2023                         /*
2024                          * binary files counts bytes, not lines. Must find some
2025                          * way to normalize binary bytes vs. textual lines.
2026                          * The following heuristic assumes that there are 64
2027                          * bytes per "line".
2028                          * This is stupid and ugly, but very cheap...
2029                          */
2030                         damage = (damage + 63) / 64;
2031                 ALLOC_GROW(dir.files, dir.nr + 1, dir.alloc);
2032                 dir.files[dir.nr].name = file->name;
2033                 dir.files[dir.nr].changed = damage;
2034                 changed += damage;
2035                 dir.nr++;
2036         }
2037
2038         /* This can happen even with many files, if everything was renames */
2039         if (!changed)
2040                 return;
2041
2042         /* Show all directories with more than x% of the changes */
2043         qsort(dir.files, dir.nr, sizeof(dir.files[0]), dirstat_compare);
2044         gather_dirstat(options, &dir, changed, "", 0);
2045 }
2046
2047 static void free_diffstat_info(struct diffstat_t *diffstat)
2048 {
2049         int i;
2050         for (i = 0; i < diffstat->nr; i++) {
2051                 struct diffstat_file *f = diffstat->files[i];
2052                 if (f->name != f->print_name)
2053                         free(f->print_name);
2054                 free(f->name);
2055                 free(f->from_name);
2056                 free(f);
2057         }
2058         free(diffstat->files);
2059 }
2060
2061 struct checkdiff_t {
2062         const char *filename;
2063         int lineno;
2064         int conflict_marker_size;
2065         struct diff_options *o;
2066         unsigned ws_rule;
2067         unsigned status;
2068 };
2069
2070 static int is_conflict_marker(const char *line, int marker_size, unsigned long len)
2071 {
2072         char firstchar;
2073         int cnt;
2074
2075         if (len < marker_size + 1)
2076                 return 0;
2077         firstchar = line[0];
2078         switch (firstchar) {
2079         case '=': case '>': case '<': case '|':
2080                 break;
2081         default:
2082                 return 0;
2083         }
2084         for (cnt = 1; cnt < marker_size; cnt++)
2085                 if (line[cnt] != firstchar)
2086                         return 0;
2087         /* line[1] thru line[marker_size-1] are same as firstchar */
2088         if (len < marker_size + 1 || !isspace(line[marker_size]))
2089                 return 0;
2090         return 1;
2091 }
2092
2093 static void checkdiff_consume(void *priv, char *line, unsigned long len)
2094 {
2095         struct checkdiff_t *data = priv;
2096         int marker_size = data->conflict_marker_size;
2097         const char *ws = diff_get_color(data->o->use_color, DIFF_WHITESPACE);
2098         const char *reset = diff_get_color(data->o->use_color, DIFF_RESET);
2099         const char *set = diff_get_color(data->o->use_color, DIFF_FILE_NEW);
2100         char *err;
2101         const char *line_prefix;
2102
2103         assert(data->o);
2104         line_prefix = diff_line_prefix(data->o);
2105
2106         if (line[0] == '+') {
2107                 unsigned bad;
2108                 data->lineno++;
2109                 if (is_conflict_marker(line + 1, marker_size, len - 1)) {
2110                         data->status |= 1;
2111                         fprintf(data->o->file,
2112                                 "%s%s:%d: leftover conflict marker\n",
2113                                 line_prefix, data->filename, data->lineno);
2114                 }
2115                 bad = ws_check(line + 1, len - 1, data->ws_rule);
2116                 if (!bad)
2117                         return;
2118                 data->status |= bad;
2119                 err = whitespace_error_string(bad);
2120                 fprintf(data->o->file, "%s%s:%d: %s.\n",
2121                         line_prefix, data->filename, data->lineno, err);
2122                 free(err);
2123                 emit_line(data->o, set, reset, line, 1);
2124                 ws_check_emit(line + 1, len - 1, data->ws_rule,
2125                               data->o->file, set, reset, ws);
2126         } else if (line[0] == ' ') {
2127                 data->lineno++;
2128         } else if (line[0] == '@') {
2129                 char *plus = strchr(line, '+');
2130                 if (plus)
2131                         data->lineno = strtol(plus, NULL, 10) - 1;
2132                 else
2133                         die("invalid diff");
2134         }
2135 }
2136
2137 static unsigned char *deflate_it(char *data,
2138                                  unsigned long size,
2139                                  unsigned long *result_size)
2140 {
2141         int bound;
2142         unsigned char *deflated;
2143         git_zstream stream;
2144
2145         git_deflate_init(&stream, zlib_compression_level);
2146         bound = git_deflate_bound(&stream, size);
2147         deflated = xmalloc(bound);
2148         stream.next_out = deflated;
2149         stream.avail_out = bound;
2150
2151         stream.next_in = (unsigned char *)data;
2152         stream.avail_in = size;
2153         while (git_deflate(&stream, Z_FINISH) == Z_OK)
2154                 ; /* nothing */
2155         git_deflate_end(&stream);
2156         *result_size = stream.total_out;
2157         return deflated;
2158 }
2159
2160 static void emit_binary_diff_body(FILE *file, mmfile_t *one, mmfile_t *two,
2161                                   const char *prefix)
2162 {
2163         void *cp;
2164         void *delta;
2165         void *deflated;
2166         void *data;
2167         unsigned long orig_size;
2168         unsigned long delta_size;
2169         unsigned long deflate_size;
2170         unsigned long data_size;
2171
2172         /* We could do deflated delta, or we could do just deflated two,
2173          * whichever is smaller.
2174          */
2175         delta = NULL;
2176         deflated = deflate_it(two->ptr, two->size, &deflate_size);
2177         if (one->size && two->size) {
2178                 delta = diff_delta(one->ptr, one->size,
2179                                    two->ptr, two->size,
2180                                    &delta_size, deflate_size);
2181                 if (delta) {
2182                         void *to_free = delta;
2183                         orig_size = delta_size;
2184                         delta = deflate_it(delta, delta_size, &delta_size);
2185                         free(to_free);
2186                 }
2187         }
2188
2189         if (delta && delta_size < deflate_size) {
2190                 fprintf(file, "%sdelta %lu\n", prefix, orig_size);
2191                 free(deflated);
2192                 data = delta;
2193                 data_size = delta_size;
2194         }
2195         else {
2196                 fprintf(file, "%sliteral %lu\n", prefix, two->size);
2197                 free(delta);
2198                 data = deflated;
2199                 data_size = deflate_size;
2200         }
2201
2202         /* emit data encoded in base85 */
2203         cp = data;
2204         while (data_size) {
2205                 int bytes = (52 < data_size) ? 52 : data_size;
2206                 char line[70];
2207                 data_size -= bytes;
2208                 if (bytes <= 26)
2209                         line[0] = bytes + 'A' - 1;
2210                 else
2211                         line[0] = bytes - 26 + 'a' - 1;
2212                 encode_85(line + 1, cp, bytes);
2213                 cp = (char *) cp + bytes;
2214                 fprintf(file, "%s", prefix);
2215                 fputs(line, file);
2216                 fputc('\n', file);
2217         }
2218         fprintf(file, "%s\n", prefix);
2219         free(data);
2220 }
2221
2222 static void emit_binary_diff(FILE *file, mmfile_t *one, mmfile_t *two,
2223                              const char *prefix)
2224 {
2225         fprintf(file, "%sGIT binary patch\n", prefix);
2226         emit_binary_diff_body(file, one, two, prefix);
2227         emit_binary_diff_body(file, two, one, prefix);
2228 }
2229
2230 int diff_filespec_is_binary(struct diff_filespec *one)
2231 {
2232         if (one->is_binary == -1) {
2233                 diff_filespec_load_driver(one);
2234                 if (one->driver->binary != -1)
2235                         one->is_binary = one->driver->binary;
2236                 else {
2237                         if (!one->data && DIFF_FILE_VALID(one))
2238                                 diff_populate_filespec(one, CHECK_BINARY);
2239                         if (one->is_binary == -1 && one->data)
2240                                 one->is_binary = buffer_is_binary(one->data,
2241                                                 one->size);
2242                         if (one->is_binary == -1)
2243                                 one->is_binary = 0;
2244                 }
2245         }
2246         return one->is_binary;
2247 }
2248
2249 static const struct userdiff_funcname *diff_funcname_pattern(struct diff_filespec *one)
2250 {
2251         diff_filespec_load_driver(one);
2252         return one->driver->funcname.pattern ? &one->driver->funcname : NULL;
2253 }
2254
2255 void diff_set_mnemonic_prefix(struct diff_options *options, const char *a, const char *b)
2256 {
2257         if (!options->a_prefix)
2258                 options->a_prefix = a;
2259         if (!options->b_prefix)
2260                 options->b_prefix = b;
2261 }
2262
2263 struct userdiff_driver *get_textconv(struct diff_filespec *one)
2264 {
2265         if (!DIFF_FILE_VALID(one))
2266                 return NULL;
2267
2268         diff_filespec_load_driver(one);
2269         return userdiff_get_textconv(one->driver);
2270 }
2271
2272 static void builtin_diff(const char *name_a,
2273                          const char *name_b,
2274                          struct diff_filespec *one,
2275                          struct diff_filespec *two,
2276                          const char *xfrm_msg,
2277                          int must_show_header,
2278                          struct diff_options *o,
2279                          int complete_rewrite)
2280 {
2281         mmfile_t mf1, mf2;
2282         const char *lbl[2];
2283         char *a_one, *b_two;
2284         const char *meta = diff_get_color_opt(o, DIFF_METAINFO);
2285         const char *reset = diff_get_color_opt(o, DIFF_RESET);
2286         const char *a_prefix, *b_prefix;
2287         struct userdiff_driver *textconv_one = NULL;
2288         struct userdiff_driver *textconv_two = NULL;
2289         struct strbuf header = STRBUF_INIT;
2290         const char *line_prefix = diff_line_prefix(o);
2291
2292         if (DIFF_OPT_TST(o, SUBMODULE_LOG) &&
2293                         (!one->mode || S_ISGITLINK(one->mode)) &&
2294                         (!two->mode || S_ISGITLINK(two->mode))) {
2295                 const char *del = diff_get_color_opt(o, DIFF_FILE_OLD);
2296                 const char *add = diff_get_color_opt(o, DIFF_FILE_NEW);
2297                 show_submodule_summary(o->file, one->path ? one->path : two->path,
2298                                 line_prefix,
2299                                 one->sha1, two->sha1, two->dirty_submodule,
2300                                 meta, del, add, reset);
2301                 return;
2302         }
2303
2304         if (DIFF_OPT_TST(o, ALLOW_TEXTCONV)) {
2305                 textconv_one = get_textconv(one);
2306                 textconv_two = get_textconv(two);
2307         }
2308
2309         diff_set_mnemonic_prefix(o, "a/", "b/");
2310         if (DIFF_OPT_TST(o, REVERSE_DIFF)) {
2311                 a_prefix = o->b_prefix;
2312                 b_prefix = o->a_prefix;
2313         } else {
2314                 a_prefix = o->a_prefix;
2315                 b_prefix = o->b_prefix;
2316         }
2317
2318         /* Never use a non-valid filename anywhere if at all possible */
2319         name_a = DIFF_FILE_VALID(one) ? name_a : name_b;
2320         name_b = DIFF_FILE_VALID(two) ? name_b : name_a;
2321
2322         a_one = quote_two(a_prefix, name_a + (*name_a == '/'));
2323         b_two = quote_two(b_prefix, name_b + (*name_b == '/'));
2324         lbl[0] = DIFF_FILE_VALID(one) ? a_one : "/dev/null";
2325         lbl[1] = DIFF_FILE_VALID(two) ? b_two : "/dev/null";
2326         strbuf_addf(&header, "%s%sdiff --git %s %s%s\n", line_prefix, meta, a_one, b_two, reset);
2327         if (lbl[0][0] == '/') {
2328                 /* /dev/null */
2329                 strbuf_addf(&header, "%s%snew file mode %06o%s\n", line_prefix, meta, two->mode, reset);
2330                 if (xfrm_msg)
2331                         strbuf_addstr(&header, xfrm_msg);
2332                 must_show_header = 1;
2333         }
2334         else if (lbl[1][0] == '/') {
2335                 strbuf_addf(&header, "%s%sdeleted file mode %06o%s\n", line_prefix, meta, one->mode, reset);
2336                 if (xfrm_msg)
2337                         strbuf_addstr(&header, xfrm_msg);
2338                 must_show_header = 1;
2339         }
2340         else {
2341                 if (one->mode != two->mode) {
2342                         strbuf_addf(&header, "%s%sold mode %06o%s\n", line_prefix, meta, one->mode, reset);
2343                         strbuf_addf(&header, "%s%snew mode %06o%s\n", line_prefix, meta, two->mode, reset);
2344                         must_show_header = 1;
2345                 }
2346                 if (xfrm_msg)
2347                         strbuf_addstr(&header, xfrm_msg);
2348
2349                 /*
2350                  * we do not run diff between different kind
2351                  * of objects.
2352                  */
2353                 if ((one->mode ^ two->mode) & S_IFMT)
2354                         goto free_ab_and_return;
2355                 if (complete_rewrite &&
2356                     (textconv_one || !diff_filespec_is_binary(one)) &&
2357                     (textconv_two || !diff_filespec_is_binary(two))) {
2358                         fprintf(o->file, "%s", header.buf);
2359                         strbuf_reset(&header);
2360                         emit_rewrite_diff(name_a, name_b, one, two,
2361                                                 textconv_one, textconv_two, o);
2362                         o->found_changes = 1;
2363                         goto free_ab_and_return;
2364                 }
2365         }
2366
2367         if (o->irreversible_delete && lbl[1][0] == '/') {
2368                 fprintf(o->file, "%s", header.buf);
2369                 strbuf_reset(&header);
2370                 goto free_ab_and_return;
2371         } else if (!DIFF_OPT_TST(o, TEXT) &&
2372             ( (!textconv_one && diff_filespec_is_binary(one)) ||
2373               (!textconv_two && diff_filespec_is_binary(two)) )) {
2374                 if (!one->data && !two->data &&
2375                     S_ISREG(one->mode) && S_ISREG(two->mode) &&
2376                     !DIFF_OPT_TST(o, BINARY)) {
2377                         if (!hashcmp(one->sha1, two->sha1)) {
2378                                 if (must_show_header)
2379                                         fprintf(o->file, "%s", header.buf);
2380                                 goto free_ab_and_return;
2381                         }
2382                         fprintf(o->file, "%s", header.buf);
2383                         fprintf(o->file, "%sBinary files %s and %s differ\n",
2384                                 line_prefix, lbl[0], lbl[1]);
2385                         goto free_ab_and_return;
2386                 }
2387                 if (fill_mmfile(&mf1, one) < 0 || fill_mmfile(&mf2, two) < 0)
2388                         die("unable to read files to diff");
2389                 /* Quite common confusing case */
2390                 if (mf1.size == mf2.size &&
2391                     !memcmp(mf1.ptr, mf2.ptr, mf1.size)) {
2392                         if (must_show_header)
2393                                 fprintf(o->file, "%s", header.buf);
2394                         goto free_ab_and_return;
2395                 }
2396                 fprintf(o->file, "%s", header.buf);
2397                 strbuf_reset(&header);
2398                 if (DIFF_OPT_TST(o, BINARY))
2399                         emit_binary_diff(o->file, &mf1, &mf2, line_prefix);
2400                 else
2401                         fprintf(o->file, "%sBinary files %s and %s differ\n",
2402                                 line_prefix, lbl[0], lbl[1]);
2403                 o->found_changes = 1;
2404         } else {
2405                 /* Crazy xdl interfaces.. */
2406                 const char *diffopts = getenv("GIT_DIFF_OPTS");
2407                 const char *v;
2408                 xpparam_t xpp;
2409                 xdemitconf_t xecfg;
2410                 struct emit_callback ecbdata;
2411                 const struct userdiff_funcname *pe;
2412
2413                 if (must_show_header) {
2414                         fprintf(o->file, "%s", header.buf);
2415                         strbuf_reset(&header);
2416                 }
2417
2418                 mf1.size = fill_textconv(textconv_one, one, &mf1.ptr);
2419                 mf2.size = fill_textconv(textconv_two, two, &mf2.ptr);
2420
2421                 pe = diff_funcname_pattern(one);
2422                 if (!pe)
2423                         pe = diff_funcname_pattern(two);
2424
2425                 memset(&xpp, 0, sizeof(xpp));
2426                 memset(&xecfg, 0, sizeof(xecfg));
2427                 memset(&ecbdata, 0, sizeof(ecbdata));
2428                 ecbdata.label_path = lbl;
2429                 ecbdata.color_diff = want_color(o->use_color);
2430                 ecbdata.found_changesp = &o->found_changes;
2431                 ecbdata.ws_rule = whitespace_rule(name_b);
2432                 if (ecbdata.ws_rule & WS_BLANK_AT_EOF)
2433                         check_blank_at_eof(&mf1, &mf2, &ecbdata);
2434                 ecbdata.opt = o;
2435                 ecbdata.header = header.len ? &header : NULL;
2436                 xpp.flags = o->xdl_opts;
2437                 xecfg.ctxlen = o->context;
2438                 xecfg.interhunkctxlen = o->interhunkcontext;
2439                 xecfg.flags = XDL_EMIT_FUNCNAMES;
2440                 if (DIFF_OPT_TST(o, FUNCCONTEXT))
2441                         xecfg.flags |= XDL_EMIT_FUNCCONTEXT;
2442                 if (pe)
2443                         xdiff_set_find_func(&xecfg, pe->pattern, pe->cflags);
2444                 if (!diffopts)
2445                         ;
2446                 else if (skip_prefix(diffopts, "--unified=", &v))
2447                         xecfg.ctxlen = strtoul(v, NULL, 10);
2448                 else if (skip_prefix(diffopts, "-u", &v))
2449                         xecfg.ctxlen = strtoul(v, NULL, 10);
2450                 if (o->word_diff)
2451                         init_diff_words_data(&ecbdata, o, one, two);
2452                 if (xdi_diff_outf(&mf1, &mf2, fn_out_consume, &ecbdata,
2453                                   &xpp, &xecfg))
2454                         die("unable to generate diff for %s", one->path);
2455                 if (o->word_diff)
2456                         free_diff_words_data(&ecbdata);
2457                 if (textconv_one)
2458                         free(mf1.ptr);
2459                 if (textconv_two)
2460                         free(mf2.ptr);
2461                 xdiff_clear_find_func(&xecfg);
2462         }
2463
2464  free_ab_and_return:
2465         strbuf_release(&header);
2466         diff_free_filespec_data(one);
2467         diff_free_filespec_data(two);
2468         free(a_one);
2469         free(b_two);
2470         return;
2471 }
2472
2473 static void builtin_diffstat(const char *name_a, const char *name_b,
2474                              struct diff_filespec *one,
2475                              struct diff_filespec *two,
2476                              struct diffstat_t *diffstat,
2477                              struct diff_options *o,
2478                              struct diff_filepair *p)
2479 {
2480         mmfile_t mf1, mf2;
2481         struct diffstat_file *data;
2482         int same_contents;
2483         int complete_rewrite = 0;
2484
2485         if (!DIFF_PAIR_UNMERGED(p)) {
2486                 if (p->status == DIFF_STATUS_MODIFIED && p->score)
2487                         complete_rewrite = 1;
2488         }
2489
2490         data = diffstat_add(diffstat, name_a, name_b);
2491         data->is_interesting = p->status != DIFF_STATUS_UNKNOWN;
2492
2493         if (!one || !two) {
2494                 data->is_unmerged = 1;
2495                 return;
2496         }
2497
2498         same_contents = !hashcmp(one->sha1, two->sha1);
2499
2500         if (diff_filespec_is_binary(one) || diff_filespec_is_binary(two)) {
2501                 data->is_binary = 1;
2502                 if (same_contents) {
2503                         data->added = 0;
2504                         data->deleted = 0;
2505                 } else {
2506                         data->added = diff_filespec_size(two);
2507                         data->deleted = diff_filespec_size(one);
2508                 }
2509         }
2510
2511         else if (complete_rewrite) {
2512                 diff_populate_filespec(one, 0);
2513                 diff_populate_filespec(two, 0);
2514                 data->deleted = count_lines(one->data, one->size);
2515                 data->added = count_lines(two->data, two->size);
2516         }
2517
2518         else if (!same_contents) {
2519                 /* Crazy xdl interfaces.. */
2520                 xpparam_t xpp;
2521                 xdemitconf_t xecfg;
2522
2523                 if (fill_mmfile(&mf1, one) < 0 || fill_mmfile(&mf2, two) < 0)
2524                         die("unable to read files to diff");
2525
2526                 memset(&xpp, 0, sizeof(xpp));
2527                 memset(&xecfg, 0, sizeof(xecfg));
2528                 xpp.flags = o->xdl_opts;
2529                 xecfg.ctxlen = o->context;
2530                 xecfg.interhunkctxlen = o->interhunkcontext;
2531                 if (xdi_diff_outf(&mf1, &mf2, diffstat_consume, diffstat,
2532                                   &xpp, &xecfg))
2533                         die("unable to generate diffstat for %s", one->path);
2534         }
2535
2536         diff_free_filespec_data(one);
2537         diff_free_filespec_data(two);
2538 }
2539
2540 static void builtin_checkdiff(const char *name_a, const char *name_b,
2541                               const char *attr_path,
2542                               struct diff_filespec *one,
2543                               struct diff_filespec *two,
2544                               struct diff_options *o)
2545 {
2546         mmfile_t mf1, mf2;
2547         struct checkdiff_t data;
2548
2549         if (!two)
2550                 return;
2551
2552         memset(&data, 0, sizeof(data));
2553         data.filename = name_b ? name_b : name_a;
2554         data.lineno = 0;
2555         data.o = o;
2556         data.ws_rule = whitespace_rule(attr_path);
2557         data.conflict_marker_size = ll_merge_marker_size(attr_path);
2558
2559         if (fill_mmfile(&mf1, one) < 0 || fill_mmfile(&mf2, two) < 0)
2560                 die("unable to read files to diff");
2561
2562         /*
2563          * All the other codepaths check both sides, but not checking
2564          * the "old" side here is deliberate.  We are checking the newly
2565          * introduced changes, and as long as the "new" side is text, we
2566          * can and should check what it introduces.
2567          */
2568         if (diff_filespec_is_binary(two))
2569                 goto free_and_return;
2570         else {
2571                 /* Crazy xdl interfaces.. */
2572                 xpparam_t xpp;
2573                 xdemitconf_t xecfg;
2574
2575                 memset(&xpp, 0, sizeof(xpp));
2576                 memset(&xecfg, 0, sizeof(xecfg));
2577                 xecfg.ctxlen = 1; /* at least one context line */
2578                 xpp.flags = 0;
2579                 if (xdi_diff_outf(&mf1, &mf2, checkdiff_consume, &data,
2580                                   &xpp, &xecfg))
2581                         die("unable to generate checkdiff for %s", one->path);
2582
2583                 if (data.ws_rule & WS_BLANK_AT_EOF) {
2584                         struct emit_callback ecbdata;
2585                         int blank_at_eof;
2586
2587                         ecbdata.ws_rule = data.ws_rule;
2588                         check_blank_at_eof(&mf1, &mf2, &ecbdata);
2589                         blank_at_eof = ecbdata.blank_at_eof_in_postimage;
2590
2591                         if (blank_at_eof) {
2592                                 static char *err;
2593                                 if (!err)
2594                                         err = whitespace_error_string(WS_BLANK_AT_EOF);
2595                                 fprintf(o->file, "%s:%d: %s.\n",
2596                                         data.filename, blank_at_eof, err);
2597                                 data.status = 1; /* report errors */
2598                         }
2599                 }
2600         }
2601  free_and_return:
2602         diff_free_filespec_data(one);
2603         diff_free_filespec_data(two);
2604         if (data.status)
2605                 DIFF_OPT_SET(o, CHECK_FAILED);
2606 }
2607
2608 struct diff_filespec *alloc_filespec(const char *path)
2609 {
2610         struct diff_filespec *spec;
2611
2612         FLEXPTR_ALLOC_STR(spec, path, path);
2613         spec->count = 1;
2614         spec->is_binary = -1;
2615         return spec;
2616 }
2617
2618 void free_filespec(struct diff_filespec *spec)
2619 {
2620         if (!--spec->count) {
2621                 diff_free_filespec_data(spec);
2622                 free(spec);
2623         }
2624 }
2625
2626 void fill_filespec(struct diff_filespec *spec, const unsigned char *sha1,
2627                    int sha1_valid, unsigned short mode)
2628 {
2629         if (mode) {
2630                 spec->mode = canon_mode(mode);
2631                 hashcpy(spec->sha1, sha1);
2632                 spec->sha1_valid = sha1_valid;
2633         }
2634 }
2635
2636 /*
2637  * Given a name and sha1 pair, if the index tells us the file in
2638  * the work tree has that object contents, return true, so that
2639  * prepare_temp_file() does not have to inflate and extract.
2640  */
2641 static int reuse_worktree_file(const char *name, const unsigned char *sha1, int want_file)
2642 {
2643         const struct cache_entry *ce;
2644         struct stat st;
2645         int pos, len;
2646
2647         /*
2648          * We do not read the cache ourselves here, because the
2649          * benchmark with my previous version that always reads cache
2650          * shows that it makes things worse for diff-tree comparing
2651          * two linux-2.6 kernel trees in an already checked out work
2652          * tree.  This is because most diff-tree comparisons deal with
2653          * only a small number of files, while reading the cache is
2654          * expensive for a large project, and its cost outweighs the
2655          * savings we get by not inflating the object to a temporary
2656          * file.  Practically, this code only helps when we are used
2657          * by diff-cache --cached, which does read the cache before
2658          * calling us.
2659          */
2660         if (!active_cache)
2661                 return 0;
2662
2663         /* We want to avoid the working directory if our caller
2664          * doesn't need the data in a normal file, this system
2665          * is rather slow with its stat/open/mmap/close syscalls,
2666          * and the object is contained in a pack file.  The pack
2667          * is probably already open and will be faster to obtain
2668          * the data through than the working directory.  Loose
2669          * objects however would tend to be slower as they need
2670          * to be individually opened and inflated.
2671          */
2672         if (!FAST_WORKING_DIRECTORY && !want_file && has_sha1_pack(sha1))
2673                 return 0;
2674
2675         len = strlen(name);
2676         pos = cache_name_pos(name, len);
2677         if (pos < 0)
2678                 return 0;
2679         ce = active_cache[pos];
2680
2681         /*
2682          * This is not the sha1 we are looking for, or
2683          * unreusable because it is not a regular file.
2684          */
2685         if (hashcmp(sha1, ce->sha1) || !S_ISREG(ce->ce_mode))
2686                 return 0;
2687
2688         /*
2689          * If ce is marked as "assume unchanged", there is no
2690          * guarantee that work tree matches what we are looking for.
2691          */
2692         if ((ce->ce_flags & CE_VALID) || ce_skip_worktree(ce))
2693                 return 0;
2694
2695         /*
2696          * If ce matches the file in the work tree, we can reuse it.
2697          */
2698         if (ce_uptodate(ce) ||
2699             (!lstat(name, &st) && !ce_match_stat(ce, &st, 0)))
2700                 return 1;
2701
2702         return 0;
2703 }
2704
2705 static int diff_populate_gitlink(struct diff_filespec *s, int size_only)
2706 {
2707         struct strbuf buf = STRBUF_INIT;
2708         char *dirty = "";
2709
2710         /* Are we looking at the work tree? */
2711         if (s->dirty_submodule)
2712                 dirty = "-dirty";
2713
2714         strbuf_addf(&buf, "Subproject commit %s%s\n", sha1_to_hex(s->sha1), dirty);
2715         s->size = buf.len;
2716         if (size_only) {
2717                 s->data = NULL;
2718                 strbuf_release(&buf);
2719         } else {
2720                 s->data = strbuf_detach(&buf, NULL);
2721                 s->should_free = 1;
2722         }
2723         return 0;
2724 }
2725
2726 /*
2727  * While doing rename detection and pickaxe operation, we may need to
2728  * grab the data for the blob (or file) for our own in-core comparison.
2729  * diff_filespec has data and size fields for this purpose.
2730  */
2731 int diff_populate_filespec(struct diff_filespec *s, unsigned int flags)
2732 {
2733         int size_only = flags & CHECK_SIZE_ONLY;
2734         int err = 0;
2735         /*
2736          * demote FAIL to WARN to allow inspecting the situation
2737          * instead of refusing.
2738          */
2739         enum safe_crlf crlf_warn = (safe_crlf == SAFE_CRLF_FAIL
2740                                     ? SAFE_CRLF_WARN
2741                                     : safe_crlf);
2742
2743         if (!DIFF_FILE_VALID(s))
2744                 die("internal error: asking to populate invalid file.");
2745         if (S_ISDIR(s->mode))
2746                 return -1;
2747
2748         if (s->data)
2749                 return 0;
2750
2751         if (size_only && 0 < s->size)
2752                 return 0;
2753
2754         if (S_ISGITLINK(s->mode))
2755                 return diff_populate_gitlink(s, size_only);
2756
2757         if (!s->sha1_valid ||
2758             reuse_worktree_file(s->path, s->sha1, 0)) {
2759                 struct strbuf buf = STRBUF_INIT;
2760                 struct stat st;
2761                 int fd;
2762
2763                 if (lstat(s->path, &st) < 0) {
2764                         if (errno == ENOENT) {
2765                         err_empty:
2766                                 err = -1;
2767                         empty:
2768                                 s->data = (char *)"";
2769                                 s->size = 0;
2770                                 return err;
2771                         }
2772                 }
2773                 s->size = xsize_t(st.st_size);
2774                 if (!s->size)
2775                         goto empty;
2776                 if (S_ISLNK(st.st_mode)) {
2777                         struct strbuf sb = STRBUF_INIT;
2778
2779                         if (strbuf_readlink(&sb, s->path, s->size))
2780                                 goto err_empty;
2781                         s->size = sb.len;
2782                         s->data = strbuf_detach(&sb, NULL);
2783                         s->should_free = 1;
2784                         return 0;
2785                 }
2786                 if (size_only)
2787                         return 0;
2788                 if ((flags & CHECK_BINARY) &&
2789                     s->size > big_file_threshold && s->is_binary == -1) {
2790                         s->is_binary = 1;
2791                         return 0;
2792                 }
2793                 fd = open(s->path, O_RDONLY);
2794                 if (fd < 0)
2795                         goto err_empty;
2796                 s->data = xmmap(NULL, s->size, PROT_READ, MAP_PRIVATE, fd, 0);
2797                 close(fd);
2798                 s->should_munmap = 1;
2799
2800                 /*
2801                  * Convert from working tree format to canonical git format
2802                  */
2803                 if (convert_to_git(s->path, s->data, s->size, &buf, crlf_warn)) {
2804                         size_t size = 0;
2805                         munmap(s->data, s->size);
2806                         s->should_munmap = 0;
2807                         s->data = strbuf_detach(&buf, &size);
2808                         s->size = size;
2809                         s->should_free = 1;
2810                 }
2811         }
2812         else {
2813                 enum object_type type;
2814                 if (size_only || (flags & CHECK_BINARY)) {
2815                         type = sha1_object_info(s->sha1, &s->size);
2816                         if (type < 0)
2817                                 die("unable to read %s", sha1_to_hex(s->sha1));
2818                         if (size_only)
2819                                 return 0;
2820                         if (s->size > big_file_threshold && s->is_binary == -1) {
2821                                 s->is_binary = 1;
2822                                 return 0;
2823                         }
2824                 }
2825                 s->data = read_sha1_file(s->sha1, &type, &s->size);
2826                 if (!s->data)
2827                         die("unable to read %s", sha1_to_hex(s->sha1));
2828                 s->should_free = 1;
2829         }
2830         return 0;
2831 }
2832
2833 void diff_free_filespec_blob(struct diff_filespec *s)
2834 {
2835         if (s->should_free)
2836                 free(s->data);
2837         else if (s->should_munmap)
2838                 munmap(s->data, s->size);
2839
2840         if (s->should_free || s->should_munmap) {
2841                 s->should_free = s->should_munmap = 0;
2842                 s->data = NULL;
2843         }
2844 }
2845
2846 void diff_free_filespec_data(struct diff_filespec *s)
2847 {
2848         diff_free_filespec_blob(s);
2849         free(s->cnt_data);
2850         s->cnt_data = NULL;
2851 }
2852
2853 static void prep_temp_blob(const char *path, struct diff_tempfile *temp,
2854                            void *blob,
2855                            unsigned long size,
2856                            const unsigned char *sha1,
2857                            int mode)
2858 {
2859         int fd;
2860         struct strbuf buf = STRBUF_INIT;
2861         struct strbuf template = STRBUF_INIT;
2862         char *path_dup = xstrdup(path);
2863         const char *base = basename(path_dup);
2864
2865         /* Generate "XXXXXX_basename.ext" */
2866         strbuf_addstr(&template, "XXXXXX_");
2867         strbuf_addstr(&template, base);
2868
2869         fd = mks_tempfile_ts(&temp->tempfile, template.buf, strlen(base) + 1);
2870         if (fd < 0)
2871                 die_errno("unable to create temp-file");
2872         if (convert_to_working_tree(path,
2873                         (const char *)blob, (size_t)size, &buf)) {
2874                 blob = buf.buf;
2875                 size = buf.len;
2876         }
2877         if (write_in_full(fd, blob, size) != size)
2878                 die_errno("unable to write temp-file");
2879         close_tempfile(&temp->tempfile);
2880         temp->name = get_tempfile_path(&temp->tempfile);
2881         sha1_to_hex_r(temp->hex, sha1);
2882         xsnprintf(temp->mode, sizeof(temp->mode), "%06o", mode);
2883         strbuf_release(&buf);
2884         strbuf_release(&template);
2885         free(path_dup);
2886 }
2887
2888 static struct diff_tempfile *prepare_temp_file(const char *name,
2889                 struct diff_filespec *one)
2890 {
2891         struct diff_tempfile *temp = claim_diff_tempfile();
2892
2893         if (!DIFF_FILE_VALID(one)) {
2894         not_a_valid_file:
2895                 /* A '-' entry produces this for file-2, and
2896                  * a '+' entry produces this for file-1.
2897                  */
2898                 temp->name = "/dev/null";
2899                 xsnprintf(temp->hex, sizeof(temp->hex), ".");
2900                 xsnprintf(temp->mode, sizeof(temp->mode), ".");
2901                 return temp;
2902         }
2903
2904         if (!S_ISGITLINK(one->mode) &&
2905             (!one->sha1_valid ||
2906              reuse_worktree_file(name, one->sha1, 1))) {
2907                 struct stat st;
2908                 if (lstat(name, &st) < 0) {
2909                         if (errno == ENOENT)
2910                                 goto not_a_valid_file;
2911                         die_errno("stat(%s)", name);
2912                 }
2913                 if (S_ISLNK(st.st_mode)) {
2914                         struct strbuf sb = STRBUF_INIT;
2915                         if (strbuf_readlink(&sb, name, st.st_size) < 0)
2916                                 die_errno("readlink(%s)", name);
2917                         prep_temp_blob(name, temp, sb.buf, sb.len,
2918                                        (one->sha1_valid ?
2919                                         one->sha1 : null_sha1),
2920                                        (one->sha1_valid ?
2921                                         one->mode : S_IFLNK));
2922                         strbuf_release(&sb);
2923                 }
2924                 else {
2925                         /* we can borrow from the file in the work tree */
2926                         temp->name = name;
2927                         if (!one->sha1_valid)
2928                                 sha1_to_hex_r(temp->hex, null_sha1);
2929                         else
2930                                 sha1_to_hex_r(temp->hex, one->sha1);
2931                         /* Even though we may sometimes borrow the
2932                          * contents from the work tree, we always want
2933                          * one->mode.  mode is trustworthy even when
2934                          * !(one->sha1_valid), as long as
2935                          * DIFF_FILE_VALID(one).
2936                          */
2937                         xsnprintf(temp->mode, sizeof(temp->mode), "%06o", one->mode);
2938                 }
2939                 return temp;
2940         }
2941         else {
2942                 if (diff_populate_filespec(one, 0))
2943                         die("cannot read data blob for %s", one->path);
2944                 prep_temp_blob(name, temp, one->data, one->size,
2945                                one->sha1, one->mode);
2946         }
2947         return temp;
2948 }
2949
2950 static void add_external_diff_name(struct argv_array *argv,
2951                                    const char *name,
2952                                    struct diff_filespec *df)
2953 {
2954         struct diff_tempfile *temp = prepare_temp_file(name, df);
2955         argv_array_push(argv, temp->name);
2956         argv_array_push(argv, temp->hex);
2957         argv_array_push(argv, temp->mode);
2958 }
2959
2960 /* An external diff command takes:
2961  *
2962  * diff-cmd name infile1 infile1-sha1 infile1-mode \
2963  *               infile2 infile2-sha1 infile2-mode [ rename-to ]
2964  *
2965  */
2966 static void run_external_diff(const char *pgm,
2967                               const char *name,
2968                               const char *other,
2969                               struct diff_filespec *one,
2970                               struct diff_filespec *two,
2971                               const char *xfrm_msg,
2972                               int complete_rewrite,
2973                               struct diff_options *o)
2974 {
2975         struct argv_array argv = ARGV_ARRAY_INIT;
2976         struct argv_array env = ARGV_ARRAY_INIT;
2977         struct diff_queue_struct *q = &diff_queued_diff;
2978
2979         argv_array_push(&argv, pgm);
2980         argv_array_push(&argv, name);
2981
2982         if (one && two) {
2983                 add_external_diff_name(&argv, name, one);
2984                 if (!other)
2985                         add_external_diff_name(&argv, name, two);
2986                 else {
2987                         add_external_diff_name(&argv, other, two);
2988                         argv_array_push(&argv, other);
2989                         argv_array_push(&argv, xfrm_msg);
2990                 }
2991         }
2992
2993         argv_array_pushf(&env, "GIT_DIFF_PATH_COUNTER=%d", ++o->diff_path_counter);
2994         argv_array_pushf(&env, "GIT_DIFF_PATH_TOTAL=%d", q->nr);
2995
2996         if (run_command_v_opt_cd_env(argv.argv, RUN_USING_SHELL, NULL, env.argv))
2997                 die(_("external diff died, stopping at %s"), name);
2998
2999         remove_tempfile();
3000         argv_array_clear(&argv);
3001         argv_array_clear(&env);
3002 }
3003
3004 static int similarity_index(struct diff_filepair *p)
3005 {
3006         return p->score * 100 / MAX_SCORE;
3007 }
3008
3009 static void fill_metainfo(struct strbuf *msg,
3010                           const char *name,
3011                           const char *other,
3012                           struct diff_filespec *one,
3013                           struct diff_filespec *two,
3014                           struct diff_options *o,
3015                           struct diff_filepair *p,
3016                           int *must_show_header,
3017                           int use_color)
3018 {
3019         const char *set = diff_get_color(use_color, DIFF_METAINFO);
3020         const char *reset = diff_get_color(use_color, DIFF_RESET);
3021         const char *line_prefix = diff_line_prefix(o);
3022
3023         *must_show_header = 1;
3024         strbuf_init(msg, PATH_MAX * 2 + 300);
3025         switch (p->status) {
3026         case DIFF_STATUS_COPIED:
3027                 strbuf_addf(msg, "%s%ssimilarity index %d%%",
3028                             line_prefix, set, similarity_index(p));
3029                 strbuf_addf(msg, "%s\n%s%scopy from ",
3030                             reset,  line_prefix, set);
3031                 quote_c_style(name, msg, NULL, 0);
3032                 strbuf_addf(msg, "%s\n%s%scopy to ", reset, line_prefix, set);
3033                 quote_c_style(other, msg, NULL, 0);
3034                 strbuf_addf(msg, "%s\n", reset);
3035                 break;
3036         case DIFF_STATUS_RENAMED:
3037                 strbuf_addf(msg, "%s%ssimilarity index %d%%",
3038                             line_prefix, set, similarity_index(p));
3039                 strbuf_addf(msg, "%s\n%s%srename from ",
3040                             reset, line_prefix, set);
3041                 quote_c_style(name, msg, NULL, 0);
3042                 strbuf_addf(msg, "%s\n%s%srename to ",
3043                             reset, line_prefix, set);
3044                 quote_c_style(other, msg, NULL, 0);
3045                 strbuf_addf(msg, "%s\n", reset);
3046                 break;
3047         case DIFF_STATUS_MODIFIED:
3048                 if (p->score) {
3049                         strbuf_addf(msg, "%s%sdissimilarity index %d%%%s\n",
3050                                     line_prefix,
3051                                     set, similarity_index(p), reset);
3052                         break;
3053                 }
3054                 /* fallthru */
3055         default:
3056                 *must_show_header = 0;
3057         }
3058         if (one && two && hashcmp(one->sha1, two->sha1)) {
3059                 int abbrev = DIFF_OPT_TST(o, FULL_INDEX) ? 40 : DEFAULT_ABBREV;
3060
3061                 if (DIFF_OPT_TST(o, BINARY)) {
3062                         mmfile_t mf;
3063                         if ((!fill_mmfile(&mf, one) && diff_filespec_is_binary(one)) ||
3064                             (!fill_mmfile(&mf, two) && diff_filespec_is_binary(two)))
3065                                 abbrev = 40;
3066                 }
3067                 strbuf_addf(msg, "%s%sindex %s..", line_prefix, set,
3068                             find_unique_abbrev(one->sha1, abbrev));
3069                 strbuf_addstr(msg, find_unique_abbrev(two->sha1, abbrev));
3070                 if (one->mode == two->mode)
3071                         strbuf_addf(msg, " %06o", one->mode);
3072                 strbuf_addf(msg, "%s\n", reset);
3073         }
3074 }
3075
3076 static void run_diff_cmd(const char *pgm,
3077                          const char *name,
3078                          const char *other,
3079                          const char *attr_path,
3080                          struct diff_filespec *one,
3081                          struct diff_filespec *two,
3082                          struct strbuf *msg,
3083                          struct diff_options *o,
3084                          struct diff_filepair *p)
3085 {
3086         const char *xfrm_msg = NULL;
3087         int complete_rewrite = (p->status == DIFF_STATUS_MODIFIED) && p->score;
3088         int must_show_header = 0;
3089
3090
3091         if (DIFF_OPT_TST(o, ALLOW_EXTERNAL)) {
3092                 struct userdiff_driver *drv = userdiff_find_by_path(attr_path);
3093                 if (drv && drv->external)
3094                         pgm = drv->external;
3095         }
3096
3097         if (msg) {
3098                 /*
3099                  * don't use colors when the header is intended for an
3100                  * external diff driver
3101                  */
3102                 fill_metainfo(msg, name, other, one, two, o, p,
3103                               &must_show_header,
3104                               want_color(o->use_color) && !pgm);
3105                 xfrm_msg = msg->len ? msg->buf : NULL;
3106         }
3107
3108         if (pgm) {
3109                 run_external_diff(pgm, name, other, one, two, xfrm_msg,
3110                                   complete_rewrite, o);
3111                 return;
3112         }
3113         if (one && two)
3114                 builtin_diff(name, other ? other : name,
3115                              one, two, xfrm_msg, must_show_header,
3116                              o, complete_rewrite);
3117         else
3118                 fprintf(o->file, "* Unmerged path %s\n", name);
3119 }
3120
3121 static void diff_fill_sha1_info(struct diff_filespec *one)
3122 {
3123         if (DIFF_FILE_VALID(one)) {
3124                 if (!one->sha1_valid) {
3125                         struct stat st;
3126                         if (one->is_stdin) {
3127                                 hashcpy(one->sha1, null_sha1);
3128                                 return;
3129                         }
3130                         if (lstat(one->path, &st) < 0)
3131                                 die_errno("stat '%s'", one->path);
3132                         if (index_path(one->sha1, one->path, &st, 0))
3133                                 die("cannot hash %s", one->path);
3134                 }
3135         }
3136         else
3137                 hashclr(one->sha1);
3138 }
3139
3140 static void strip_prefix(int prefix_length, const char **namep, const char **otherp)
3141 {
3142         /* Strip the prefix but do not molest /dev/null and absolute paths */
3143         if (*namep && **namep != '/') {
3144                 *namep += prefix_length;
3145                 if (**namep == '/')
3146                         ++*namep;
3147         }
3148         if (*otherp && **otherp != '/') {
3149                 *otherp += prefix_length;
3150                 if (**otherp == '/')
3151                         ++*otherp;
3152         }
3153 }
3154
3155 static void run_diff(struct diff_filepair *p, struct diff_options *o)
3156 {
3157         const char *pgm = external_diff();
3158         struct strbuf msg;
3159         struct diff_filespec *one = p->one;
3160         struct diff_filespec *two = p->two;
3161         const char *name;
3162         const char *other;
3163         const char *attr_path;
3164
3165         name  = p->one->path;
3166         other = (strcmp(name, p->two->path) ? p->two->path : NULL);
3167         attr_path = name;
3168         if (o->prefix_length)
3169                 strip_prefix(o->prefix_length, &name, &other);
3170
3171         if (!DIFF_OPT_TST(o, ALLOW_EXTERNAL))
3172                 pgm = NULL;
3173
3174         if (DIFF_PAIR_UNMERGED(p)) {
3175                 run_diff_cmd(pgm, name, NULL, attr_path,
3176                              NULL, NULL, NULL, o, p);
3177                 return;
3178         }
3179
3180         diff_fill_sha1_info(one);
3181         diff_fill_sha1_info(two);
3182
3183         if (!pgm &&
3184             DIFF_FILE_VALID(one) && DIFF_FILE_VALID(two) &&
3185             (S_IFMT & one->mode) != (S_IFMT & two->mode)) {
3186                 /*
3187                  * a filepair that changes between file and symlink
3188                  * needs to be split into deletion and creation.
3189                  */
3190                 struct diff_filespec *null = alloc_filespec(two->path);
3191                 run_diff_cmd(NULL, name, other, attr_path,
3192                              one, null, &msg, o, p);
3193                 free(null);
3194                 strbuf_release(&msg);
3195
3196                 null = alloc_filespec(one->path);
3197                 run_diff_cmd(NULL, name, other, attr_path,
3198                              null, two, &msg, o, p);
3199                 free(null);
3200         }
3201         else
3202                 run_diff_cmd(pgm, name, other, attr_path,
3203                              one, two, &msg, o, p);
3204
3205         strbuf_release(&msg);
3206 }
3207
3208 static void run_diffstat(struct diff_filepair *p, struct diff_options *o,
3209                          struct diffstat_t *diffstat)
3210 {
3211         const char *name;
3212         const char *other;
3213
3214         if (DIFF_PAIR_UNMERGED(p)) {
3215                 /* unmerged */
3216                 builtin_diffstat(p->one->path, NULL, NULL, NULL, diffstat, o, p);
3217                 return;
3218         }
3219
3220         name = p->one->path;
3221         other = (strcmp(name, p->two->path) ? p->two->path : NULL);
3222
3223         if (o->prefix_length)
3224                 strip_prefix(o->prefix_length, &name, &other);
3225
3226         diff_fill_sha1_info(p->one);
3227         diff_fill_sha1_info(p->two);
3228
3229         builtin_diffstat(name, other, p->one, p->two, diffstat, o, p);
3230 }
3231
3232 static void run_checkdiff(struct diff_filepair *p, struct diff_options *o)
3233 {
3234         const char *name;
3235         const char *other;
3236         const char *attr_path;
3237
3238         if (DIFF_PAIR_UNMERGED(p)) {
3239                 /* unmerged */
3240                 return;
3241         }
3242
3243         name = p->one->path;
3244         other = (strcmp(name, p->two->path) ? p->two->path : NULL);
3245         attr_path = other ? other : name;
3246
3247         if (o->prefix_length)
3248                 strip_prefix(o->prefix_length, &name, &other);
3249
3250         diff_fill_sha1_info(p->one);
3251         diff_fill_sha1_info(p->two);
3252
3253         builtin_checkdiff(name, other, attr_path, p->one, p->two, o);
3254 }
3255
3256 void diff_setup(struct diff_options *options)
3257 {
3258         memcpy(options, &default_diff_options, sizeof(*options));
3259
3260         options->file = stdout;
3261
3262         options->line_termination = '\n';
3263         options->break_opt = -1;
3264         options->rename_limit = -1;
3265         options->dirstat_permille = diff_dirstat_permille_default;
3266         options->context = diff_context_default;
3267         options->ws_error_highlight = WSEH_NEW;
3268         DIFF_OPT_SET(options, RENAME_EMPTY);
3269
3270         /* pathchange left =NULL by default */
3271         options->change = diff_change;
3272         options->add_remove = diff_addremove;
3273         options->use_color = diff_use_color_default;
3274         options->detect_rename = diff_detect_rename_default;
3275         options->xdl_opts |= diff_algorithm;
3276
3277         options->orderfile = diff_order_file_cfg;
3278
3279         if (diff_no_prefix) {
3280                 options->a_prefix = options->b_prefix = "";
3281         } else if (!diff_mnemonic_prefix) {
3282                 options->a_prefix = "a/";
3283                 options->b_prefix = "b/";
3284         }
3285 }
3286
3287 void diff_setup_done(struct diff_options *options)
3288 {
3289         int count = 0;
3290
3291         if (options->set_default)
3292                 options->set_default(options);
3293
3294         if (options->output_format & DIFF_FORMAT_NAME)
3295                 count++;
3296         if (options->output_format & DIFF_FORMAT_NAME_STATUS)
3297                 count++;
3298         if (options->output_format & DIFF_FORMAT_CHECKDIFF)
3299                 count++;
3300         if (options->output_format & DIFF_FORMAT_NO_OUTPUT)
3301                 count++;
3302         if (count > 1)
3303                 die("--name-only, --name-status, --check and -s are mutually exclusive");
3304
3305         /*
3306          * Most of the time we can say "there are changes"
3307          * only by checking if there are changed paths, but
3308          * --ignore-whitespace* options force us to look
3309          * inside contents.
3310          */
3311
3312         if (DIFF_XDL_TST(options, IGNORE_WHITESPACE) ||
3313             DIFF_XDL_TST(options, IGNORE_WHITESPACE_CHANGE) ||
3314             DIFF_XDL_TST(options, IGNORE_WHITESPACE_AT_EOL))
3315                 DIFF_OPT_SET(options, DIFF_FROM_CONTENTS);
3316         else
3317                 DIFF_OPT_CLR(options, DIFF_FROM_CONTENTS);
3318
3319         if (DIFF_OPT_TST(options, FIND_COPIES_HARDER))
3320                 options->detect_rename = DIFF_DETECT_COPY;
3321
3322         if (!DIFF_OPT_TST(options, RELATIVE_NAME))
3323                 options->prefix = NULL;
3324         if (options->prefix)
3325                 options->prefix_length = strlen(options->prefix);
3326         else
3327                 options->prefix_length = 0;
3328
3329         if (options->output_format & (DIFF_FORMAT_NAME |
3330                                       DIFF_FORMAT_NAME_STATUS |
3331                                       DIFF_FORMAT_CHECKDIFF |
3332                                       DIFF_FORMAT_NO_OUTPUT))
3333                 options->output_format &= ~(DIFF_FORMAT_RAW |
3334                                             DIFF_FORMAT_NUMSTAT |
3335                                             DIFF_FORMAT_DIFFSTAT |
3336                                             DIFF_FORMAT_SHORTSTAT |
3337                                             DIFF_FORMAT_DIRSTAT |
3338                                             DIFF_FORMAT_SUMMARY |
3339                                             DIFF_FORMAT_PATCH);
3340
3341         /*
3342          * These cases always need recursive; we do not drop caller-supplied
3343          * recursive bits for other formats here.
3344          */
3345         if (options->output_format & (DIFF_FORMAT_PATCH |
3346                                       DIFF_FORMAT_NUMSTAT |
3347                                       DIFF_FORMAT_DIFFSTAT |
3348                                       DIFF_FORMAT_SHORTSTAT |
3349                                       DIFF_FORMAT_DIRSTAT |
3350                                       DIFF_FORMAT_SUMMARY |
3351                                       DIFF_FORMAT_CHECKDIFF))
3352                 DIFF_OPT_SET(options, RECURSIVE);
3353         /*
3354          * Also pickaxe would not work very well if you do not say recursive
3355          */
3356         if (options->pickaxe)
3357                 DIFF_OPT_SET(options, RECURSIVE);
3358         /*
3359          * When patches are generated, submodules diffed against the work tree
3360          * must be checked for dirtiness too so it can be shown in the output
3361          */
3362         if (options->output_format & DIFF_FORMAT_PATCH)
3363                 DIFF_OPT_SET(options, DIRTY_SUBMODULES);
3364
3365         if (options->detect_rename && options->rename_limit < 0)
3366                 options->rename_limit = diff_rename_limit_default;
3367         if (options->setup & DIFF_SETUP_USE_CACHE) {
3368                 if (!active_cache)
3369                         /* read-cache does not die even when it fails
3370                          * so it is safe for us to do this here.  Also
3371                          * it does not smudge active_cache or active_nr
3372                          * when it fails, so we do not have to worry about
3373                          * cleaning it up ourselves either.
3374                          */
3375                         read_cache();
3376         }
3377         if (options->abbrev <= 0 || 40 < options->abbrev)
3378                 options->abbrev = 40; /* full */
3379
3380         /*
3381          * It does not make sense to show the first hit we happened
3382          * to have found.  It does not make sense not to return with
3383          * exit code in such a case either.
3384          */
3385         if (DIFF_OPT_TST(options, QUICK)) {
3386                 options->output_format = DIFF_FORMAT_NO_OUTPUT;
3387                 DIFF_OPT_SET(options, EXIT_WITH_STATUS);
3388         }
3389
3390         options->diff_path_counter = 0;
3391
3392         if (DIFF_OPT_TST(options, FOLLOW_RENAMES) && options->pathspec.nr != 1)
3393                 die(_("--follow requires exactly one pathspec"));
3394 }
3395
3396 static int opt_arg(const char *arg, int arg_short, const char *arg_long, int *val)
3397 {
3398         char c, *eq;
3399         int len;
3400
3401         if (*arg != '-')
3402                 return 0;
3403         c = *++arg;
3404         if (!c)
3405                 return 0;
3406         if (c == arg_short) {
3407                 c = *++arg;
3408                 if (!c)
3409                         return 1;
3410                 if (val && isdigit(c)) {
3411                         char *end;
3412                         int n = strtoul(arg, &end, 10);
3413                         if (*end)
3414                                 return 0;
3415                         *val = n;
3416                         return 1;
3417                 }
3418                 return 0;
3419         }
3420         if (c != '-')
3421                 return 0;
3422         arg++;
3423         eq = strchrnul(arg, '=');
3424         len = eq - arg;
3425         if (!len || strncmp(arg, arg_long, len))
3426                 return 0;
3427         if (*eq) {
3428                 int n;
3429                 char *end;
3430                 if (!isdigit(*++eq))
3431                         return 0;
3432                 n = strtoul(eq, &end, 10);
3433                 if (*end)
3434                         return 0;
3435                 *val = n;
3436         }
3437         return 1;
3438 }
3439
3440 static int diff_scoreopt_parse(const char *opt);
3441
3442 static inline int short_opt(char opt, const char **argv,
3443                             const char **optarg)
3444 {
3445         const char *arg = argv[0];
3446         if (arg[0] != '-' || arg[1] != opt)
3447                 return 0;
3448         if (arg[2] != '\0') {
3449                 *optarg = arg + 2;
3450                 return 1;
3451         }
3452         if (!argv[1])
3453                 die("Option '%c' requires a value", opt);
3454         *optarg = argv[1];
3455         return 2;
3456 }
3457
3458 int parse_long_opt(const char *opt, const char **argv,
3459                    const char **optarg)
3460 {
3461         const char *arg = argv[0];
3462         if (!skip_prefix(arg, "--", &arg))
3463                 return 0;
3464         if (!skip_prefix(arg, opt, &arg))
3465                 return 0;
3466         if (*arg == '=') { /* stuck form: --option=value */
3467                 *optarg = arg + 1;
3468                 return 1;
3469         }
3470         if (*arg != '\0')
3471                 return 0;
3472         /* separate form: --option value */
3473         if (!argv[1])
3474                 die("Option '--%s' requires a value", opt);
3475         *optarg = argv[1];
3476         return 2;
3477 }
3478
3479 static int stat_opt(struct diff_options *options, const char **av)
3480 {
3481         const char *arg = av[0];
3482         char *end;
3483         int width = options->stat_width;
3484         int name_width = options->stat_name_width;
3485         int graph_width = options->stat_graph_width;
3486         int count = options->stat_count;
3487         int argcount = 1;
3488
3489         if (!skip_prefix(arg, "--stat", &arg))
3490                 die("BUG: stat option does not begin with --stat: %s", arg);
3491         end = (char *)arg;
3492
3493         switch (*arg) {
3494         case '-':
3495                 if (skip_prefix(arg, "-width", &arg)) {
3496                         if (*arg == '=')
3497                                 width = strtoul(arg + 1, &end, 10);
3498                         else if (!*arg && !av[1])
3499                                 die("Option '--stat-width' requires a value");
3500                         else if (!*arg) {
3501                                 width = strtoul(av[1], &end, 10);
3502                                 argcount = 2;
3503                         }
3504                 } else if (skip_prefix(arg, "-name-width", &arg)) {
3505                         if (*arg == '=')
3506                                 name_width = strtoul(arg + 1, &end, 10);
3507                         else if (!*arg && !av[1])
3508                                 die("Option '--stat-name-width' requires a value");
3509                         else if (!*arg) {
3510                                 name_width = strtoul(av[1], &end, 10);
3511                                 argcount = 2;
3512                         }
3513                 } else if (skip_prefix(arg, "-graph-width", &arg)) {
3514                         if (*arg == '=')
3515                                 graph_width = strtoul(arg + 1, &end, 10);
3516                         else if (!*arg && !av[1])
3517                                 die("Option '--stat-graph-width' requires a value");
3518                         else if (!*arg) {
3519                                 graph_width = strtoul(av[1], &end, 10);
3520                                 argcount = 2;
3521                         }
3522                 } else if (skip_prefix(arg, "-count", &arg)) {
3523                         if (*arg == '=')
3524                                 count = strtoul(arg + 1, &end, 10);
3525                         else if (!*arg && !av[1])
3526                                 die("Option '--stat-count' requires a value");
3527                         else if (!*arg) {
3528                                 count = strtoul(av[1], &end, 10);
3529                                 argcount = 2;
3530                         }
3531                 }
3532                 break;
3533         case '=':
3534                 width = strtoul(arg+1, &end, 10);
3535                 if (*end == ',')
3536                         name_width = strtoul(end+1, &end, 10);
3537                 if (*end == ',')
3538                         count = strtoul(end+1, &end, 10);
3539         }
3540
3541         /* Important! This checks all the error cases! */
3542         if (*end)
3543                 return 0;
3544         options->output_format |= DIFF_FORMAT_DIFFSTAT;
3545         options->stat_name_width = name_width;
3546         options->stat_graph_width = graph_width;
3547         options->stat_width = width;
3548         options->stat_count = count;
3549         return argcount;
3550 }
3551
3552 static int parse_dirstat_opt(struct diff_options *options, const char *params)
3553 {
3554         struct strbuf errmsg = STRBUF_INIT;
3555         if (parse_dirstat_params(options, params, &errmsg))
3556                 die(_("Failed to parse --dirstat/-X option parameter:\n%s"),
3557                     errmsg.buf);
3558         strbuf_release(&errmsg);
3559         /*
3560          * The caller knows a dirstat-related option is given from the command
3561          * line; allow it to say "return this_function();"
3562          */
3563         options->output_format |= DIFF_FORMAT_DIRSTAT;
3564         return 1;
3565 }
3566
3567 static int parse_submodule_opt(struct diff_options *options, const char *value)
3568 {
3569         if (parse_submodule_params(options, value))
3570                 die(_("Failed to parse --submodule option parameter: '%s'"),
3571                         value);
3572         return 1;
3573 }
3574
3575 static const char diff_status_letters[] = {
3576         DIFF_STATUS_ADDED,
3577         DIFF_STATUS_COPIED,
3578         DIFF_STATUS_DELETED,
3579         DIFF_STATUS_MODIFIED,
3580         DIFF_STATUS_RENAMED,
3581         DIFF_STATUS_TYPE_CHANGED,
3582         DIFF_STATUS_UNKNOWN,
3583         DIFF_STATUS_UNMERGED,
3584         DIFF_STATUS_FILTER_AON,
3585         DIFF_STATUS_FILTER_BROKEN,
3586         '\0',
3587 };
3588
3589 static unsigned int filter_bit['Z' + 1];
3590
3591 static void prepare_filter_bits(void)
3592 {
3593         int i;
3594
3595         if (!filter_bit[DIFF_STATUS_ADDED]) {
3596                 for (i = 0; diff_status_letters[i]; i++)
3597                         filter_bit[(int) diff_status_letters[i]] = (1 << i);
3598         }
3599 }
3600
3601 static unsigned filter_bit_tst(char status, const struct diff_options *opt)
3602 {
3603         return opt->filter & filter_bit[(int) status];
3604 }
3605
3606 static int parse_diff_filter_opt(const char *optarg, struct diff_options *opt)
3607 {
3608         int i, optch;
3609
3610         prepare_filter_bits();
3611
3612         /*
3613          * If there is a negation e.g. 'd' in the input, and we haven't
3614          * initialized the filter field with another --diff-filter, start
3615          * from full set of bits, except for AON.
3616          */
3617         if (!opt->filter) {
3618                 for (i = 0; (optch = optarg[i]) != '\0'; i++) {
3619                         if (optch < 'a' || 'z' < optch)
3620                                 continue;
3621                         opt->filter = (1 << (ARRAY_SIZE(diff_status_letters) - 1)) - 1;
3622                         opt->filter &= ~filter_bit[DIFF_STATUS_FILTER_AON];
3623                         break;
3624                 }
3625         }
3626
3627         for (i = 0; (optch = optarg[i]) != '\0'; i++) {
3628                 unsigned int bit;
3629                 int negate;
3630
3631                 if ('a' <= optch && optch <= 'z') {
3632                         negate = 1;
3633                         optch = toupper(optch);
3634                 } else {
3635                         negate = 0;
3636                 }
3637
3638                 bit = (0 <= optch && optch <= 'Z') ? filter_bit[optch] : 0;
3639                 if (!bit)
3640                         return optarg[i];
3641                 if (negate)
3642                         opt->filter &= ~bit;
3643                 else
3644                         opt->filter |= bit;
3645         }
3646         return 0;
3647 }
3648
3649 static void enable_patch_output(int *fmt) {
3650         *fmt &= ~DIFF_FORMAT_NO_OUTPUT;
3651         *fmt |= DIFF_FORMAT_PATCH;
3652 }
3653
3654 static int parse_one_token(const char **arg, const char *token)
3655 {
3656         const char *rest;
3657         if (skip_prefix(*arg, token, &rest) && (!*rest || *rest == ',')) {
3658                 *arg = rest;
3659                 return 1;
3660         }
3661         return 0;
3662 }
3663
3664 static int parse_ws_error_highlight(struct diff_options *opt, const char *arg)
3665 {
3666         const char *orig_arg = arg;
3667         unsigned val = 0;
3668         while (*arg) {
3669                 if (parse_one_token(&arg, "none"))
3670                         val = 0;
3671                 else if (parse_one_token(&arg, "default"))
3672                         val = WSEH_NEW;
3673                 else if (parse_one_token(&arg, "all"))
3674                         val = WSEH_NEW | WSEH_OLD | WSEH_CONTEXT;
3675                 else if (parse_one_token(&arg, "new"))
3676                         val |= WSEH_NEW;
3677                 else if (parse_one_token(&arg, "old"))
3678                         val |= WSEH_OLD;
3679                 else if (parse_one_token(&arg, "context"))
3680                         val |= WSEH_CONTEXT;
3681                 else {
3682                         error("unknown value after ws-error-highlight=%.*s",
3683                               (int)(arg - orig_arg), orig_arg);
3684                         return 0;
3685                 }
3686                 if (*arg)
3687                         arg++;
3688         }
3689         opt->ws_error_highlight = val;
3690         return 1;
3691 }
3692
3693 int diff_opt_parse(struct diff_options *options,
3694                    const char **av, int ac, const char *prefix)
3695 {
3696         const char *arg = av[0];
3697         const char *optarg;
3698         int argcount;
3699
3700         if (!prefix)
3701                 prefix = "";
3702
3703         /* Output format options */
3704         if (!strcmp(arg, "-p") || !strcmp(arg, "-u") || !strcmp(arg, "--patch")
3705             || opt_arg(arg, 'U', "unified", &options->context))
3706                 enable_patch_output(&options->output_format);
3707         else if (!strcmp(arg, "--raw"))
3708                 options->output_format |= DIFF_FORMAT_RAW;
3709         else if (!strcmp(arg, "--patch-with-raw")) {
3710                 enable_patch_output(&options->output_format);
3711                 options->output_format |= DIFF_FORMAT_RAW;
3712         } else if (!strcmp(arg, "--numstat"))
3713                 options->output_format |= DIFF_FORMAT_NUMSTAT;
3714         else if (!strcmp(arg, "--shortstat"))
3715                 options->output_format |= DIFF_FORMAT_SHORTSTAT;
3716         else if (!strcmp(arg, "-X") || !strcmp(arg, "--dirstat"))
3717                 return parse_dirstat_opt(options, "");
3718         else if (skip_prefix(arg, "-X", &arg))
3719                 return parse_dirstat_opt(options, arg);
3720         else if (skip_prefix(arg, "--dirstat=", &arg))
3721                 return parse_dirstat_opt(options, arg);
3722         else if (!strcmp(arg, "--cumulative"))
3723                 return parse_dirstat_opt(options, "cumulative");
3724         else if (!strcmp(arg, "--dirstat-by-file"))
3725                 return parse_dirstat_opt(options, "files");
3726         else if (skip_prefix(arg, "--dirstat-by-file=", &arg)) {
3727                 parse_dirstat_opt(options, "files");
3728                 return parse_dirstat_opt(options, arg);
3729         }
3730         else if (!strcmp(arg, "--check"))
3731                 options->output_format |= DIFF_FORMAT_CHECKDIFF;
3732         else if (!strcmp(arg, "--summary"))
3733                 options->output_format |= DIFF_FORMAT_SUMMARY;
3734         else if (!strcmp(arg, "--patch-with-stat")) {
3735                 enable_patch_output(&options->output_format);
3736                 options->output_format |= DIFF_FORMAT_DIFFSTAT;
3737         } else if (!strcmp(arg, "--name-only"))
3738                 options->output_format |= DIFF_FORMAT_NAME;
3739         else if (!strcmp(arg, "--name-status"))
3740                 options->output_format |= DIFF_FORMAT_NAME_STATUS;
3741         else if (!strcmp(arg, "-s") || !strcmp(arg, "--no-patch"))
3742                 options->output_format |= DIFF_FORMAT_NO_OUTPUT;
3743         else if (starts_with(arg, "--stat"))
3744                 /* --stat, --stat-width, --stat-name-width, or --stat-count */
3745                 return stat_opt(options, av);
3746
3747         /* renames options */
3748         else if (starts_with(arg, "-B") || starts_with(arg, "--break-rewrites=") ||
3749                  !strcmp(arg, "--break-rewrites")) {
3750                 if ((options->break_opt = diff_scoreopt_parse(arg)) == -1)
3751                         return error("invalid argument to -B: %s", arg+2);
3752         }
3753         else if (starts_with(arg, "-M") || starts_with(arg, "--find-renames=") ||
3754                  !strcmp(arg, "--find-renames")) {
3755                 if ((options->rename_score = diff_scoreopt_parse(arg)) == -1)
3756                         return error("invalid argument to -M: %s", arg+2);
3757                 options->detect_rename = DIFF_DETECT_RENAME;
3758         }
3759         else if (!strcmp(arg, "-D") || !strcmp(arg, "--irreversible-delete")) {
3760                 options->irreversible_delete = 1;
3761         }
3762         else if (starts_with(arg, "-C") || starts_with(arg, "--find-copies=") ||
3763                  !strcmp(arg, "--find-copies")) {
3764                 if (options->detect_rename == DIFF_DETECT_COPY)
3765                         DIFF_OPT_SET(options, FIND_COPIES_HARDER);
3766                 if ((options->rename_score = diff_scoreopt_parse(arg)) == -1)
3767                         return error("invalid argument to -C: %s", arg+2);
3768                 options->detect_rename = DIFF_DETECT_COPY;
3769         }
3770         else if (!strcmp(arg, "--no-renames"))
3771                 options->detect_rename = 0;
3772         else if (!strcmp(arg, "--rename-empty"))
3773                 DIFF_OPT_SET(options, RENAME_EMPTY);
3774         else if (!strcmp(arg, "--no-rename-empty"))
3775                 DIFF_OPT_CLR(options, RENAME_EMPTY);
3776         else if (!strcmp(arg, "--relative"))
3777                 DIFF_OPT_SET(options, RELATIVE_NAME);
3778         else if (skip_prefix(arg, "--relative=", &arg)) {
3779                 DIFF_OPT_SET(options, RELATIVE_NAME);
3780                 options->prefix = arg;
3781         }
3782
3783         /* xdiff options */
3784         else if (!strcmp(arg, "--minimal"))
3785                 DIFF_XDL_SET(options, NEED_MINIMAL);
3786         else if (!strcmp(arg, "--no-minimal"))
3787                 DIFF_XDL_CLR(options, NEED_MINIMAL);
3788         else if (!strcmp(arg, "-w") || !strcmp(arg, "--ignore-all-space"))
3789                 DIFF_XDL_SET(options, IGNORE_WHITESPACE);
3790         else if (!strcmp(arg, "-b") || !strcmp(arg, "--ignore-space-change"))
3791                 DIFF_XDL_SET(options, IGNORE_WHITESPACE_CHANGE);
3792         else if (!strcmp(arg, "--ignore-space-at-eol"))
3793                 DIFF_XDL_SET(options, IGNORE_WHITESPACE_AT_EOL);
3794         else if (!strcmp(arg, "--ignore-blank-lines"))
3795                 DIFF_XDL_SET(options, IGNORE_BLANK_LINES);
3796         else if (!strcmp(arg, "--patience"))
3797                 options->xdl_opts = DIFF_WITH_ALG(options, PATIENCE_DIFF);
3798         else if (!strcmp(arg, "--histogram"))
3799                 options->xdl_opts = DIFF_WITH_ALG(options, HISTOGRAM_DIFF);
3800         else if ((argcount = parse_long_opt("diff-algorithm", av, &optarg))) {
3801                 long value = parse_algorithm_value(optarg);
3802                 if (value < 0)
3803                         return error("option diff-algorithm accepts \"myers\", "
3804                                      "\"minimal\", \"patience\" and \"histogram\"");
3805                 /* clear out previous settings */
3806                 DIFF_XDL_CLR(options, NEED_MINIMAL);
3807                 options->xdl_opts &= ~XDF_DIFF_ALGORITHM_MASK;
3808                 options->xdl_opts |= value;
3809                 return argcount;
3810         }
3811
3812         /* flags options */
3813         else if (!strcmp(arg, "--binary")) {
3814                 enable_patch_output(&options->output_format);
3815                 DIFF_OPT_SET(options, BINARY);
3816         }
3817         else if (!strcmp(arg, "--full-index"))
3818                 DIFF_OPT_SET(options, FULL_INDEX);
3819         else if (!strcmp(arg, "-a") || !strcmp(arg, "--text"))
3820                 DIFF_OPT_SET(options, TEXT);
3821         else if (!strcmp(arg, "-R"))
3822                 DIFF_OPT_SET(options, REVERSE_DIFF);
3823         else if (!strcmp(arg, "--find-copies-harder"))
3824                 DIFF_OPT_SET(options, FIND_COPIES_HARDER);
3825         else if (!strcmp(arg, "--follow"))
3826                 DIFF_OPT_SET(options, FOLLOW_RENAMES);
3827         else if (!strcmp(arg, "--no-follow")) {
3828                 DIFF_OPT_CLR(options, FOLLOW_RENAMES);
3829                 DIFF_OPT_CLR(options, DEFAULT_FOLLOW_RENAMES);
3830         } else if (!strcmp(arg, "--color"))
3831                 options->use_color = 1;
3832         else if (skip_prefix(arg, "--color=", &arg)) {
3833                 int value = git_config_colorbool(NULL, arg);
3834                 if (value < 0)
3835                         return error("option `color' expects \"always\", \"auto\", or \"never\"");
3836                 options->use_color = value;
3837         }
3838         else if (!strcmp(arg, "--no-color"))
3839                 options->use_color = 0;
3840         else if (!strcmp(arg, "--color-words")) {
3841                 options->use_color = 1;
3842                 options->word_diff = DIFF_WORDS_COLOR;
3843         }
3844         else if (skip_prefix(arg, "--color-words=", &arg)) {
3845                 options->use_color = 1;
3846                 options->word_diff = DIFF_WORDS_COLOR;
3847                 options->word_regex = arg;
3848         }
3849         else if (!strcmp(arg, "--word-diff")) {
3850                 if (options->word_diff == DIFF_WORDS_NONE)
3851                         options->word_diff = DIFF_WORDS_PLAIN;
3852         }
3853         else if (skip_prefix(arg, "--word-diff=", &arg)) {
3854                 if (!strcmp(arg, "plain"))
3855                         options->word_diff = DIFF_WORDS_PLAIN;
3856                 else if (!strcmp(arg, "color")) {
3857                         options->use_color = 1;
3858                         options->word_diff = DIFF_WORDS_COLOR;
3859                 }
3860                 else if (!strcmp(arg, "porcelain"))
3861                         options->word_diff = DIFF_WORDS_PORCELAIN;
3862                 else if (!strcmp(arg, "none"))
3863                         options->word_diff = DIFF_WORDS_NONE;
3864                 else
3865                         die("bad --word-diff argument: %s", arg);
3866         }
3867         else if ((argcount = parse_long_opt("word-diff-regex", av, &optarg))) {
3868                 if (options->word_diff == DIFF_WORDS_NONE)
3869                         options->word_diff = DIFF_WORDS_PLAIN;
3870                 options->word_regex = optarg;
3871                 return argcount;
3872         }
3873         else if (!strcmp(arg, "--exit-code"))
3874                 DIFF_OPT_SET(options, EXIT_WITH_STATUS);
3875         else if (!strcmp(arg, "--quiet"))
3876                 DIFF_OPT_SET(options, QUICK);
3877         else if (!strcmp(arg, "--ext-diff"))
3878                 DIFF_OPT_SET(options, ALLOW_EXTERNAL);
3879         else if (!strcmp(arg, "--no-ext-diff"))
3880                 DIFF_OPT_CLR(options, ALLOW_EXTERNAL);
3881         else if (!strcmp(arg, "--textconv"))
3882                 DIFF_OPT_SET(options, ALLOW_TEXTCONV);
3883         else if (!strcmp(arg, "--no-textconv"))
3884                 DIFF_OPT_CLR(options, ALLOW_TEXTCONV);
3885         else if (!strcmp(arg, "--ignore-submodules")) {
3886                 DIFF_OPT_SET(options, OVERRIDE_SUBMODULE_CONFIG);
3887                 handle_ignore_submodules_arg(options, "all");
3888         } else if (skip_prefix(arg, "--ignore-submodules=", &arg)) {
3889                 DIFF_OPT_SET(options, OVERRIDE_SUBMODULE_CONFIG);
3890                 handle_ignore_submodules_arg(options, arg);
3891         } else if (!strcmp(arg, "--submodule"))
3892                 DIFF_OPT_SET(options, SUBMODULE_LOG);
3893         else if (skip_prefix(arg, "--submodule=", &arg))
3894                 return parse_submodule_opt(options, arg);
3895         else if (skip_prefix(arg, "--ws-error-highlight=", &arg))
3896                 return parse_ws_error_highlight(options, arg);
3897
3898         /* misc options */
3899         else if (!strcmp(arg, "-z"))
3900                 options->line_termination = 0;
3901         else if ((argcount = short_opt('l', av, &optarg))) {
3902                 options->rename_limit = strtoul(optarg, NULL, 10);
3903                 return argcount;
3904         }
3905         else if ((argcount = short_opt('S', av, &optarg))) {
3906                 options->pickaxe = optarg;
3907                 options->pickaxe_opts |= DIFF_PICKAXE_KIND_S;
3908                 return argcount;
3909         } else if ((argcount = short_opt('G', av, &optarg))) {
3910                 options->pickaxe = optarg;
3911                 options->pickaxe_opts |= DIFF_PICKAXE_KIND_G;
3912                 return argcount;
3913         }
3914         else if (!strcmp(arg, "--pickaxe-all"))
3915                 options->pickaxe_opts |= DIFF_PICKAXE_ALL;
3916         else if (!strcmp(arg, "--pickaxe-regex"))
3917                 options->pickaxe_opts |= DIFF_PICKAXE_REGEX;
3918         else if ((argcount = short_opt('O', av, &optarg))) {
3919                 const char *path = prefix_filename(prefix, strlen(prefix), optarg);
3920                 options->orderfile = xstrdup(path);
3921                 return argcount;
3922         }
3923         else if ((argcount = parse_long_opt("diff-filter", av, &optarg))) {
3924                 int offending = parse_diff_filter_opt(optarg, options);
3925                 if (offending)
3926                         die("unknown change class '%c' in --diff-filter=%s",
3927                             offending, optarg);
3928                 return argcount;
3929         }
3930         else if (!strcmp(arg, "--abbrev"))
3931                 options->abbrev = DEFAULT_ABBREV;
3932         else if (skip_prefix(arg, "--abbrev=", &arg)) {
3933                 options->abbrev = strtoul(arg, NULL, 10);
3934                 if (options->abbrev < MINIMUM_ABBREV)
3935                         options->abbrev = MINIMUM_ABBREV;
3936                 else if (40 < options->abbrev)
3937                         options->abbrev = 40;
3938         }
3939         else if ((argcount = parse_long_opt("src-prefix", av, &optarg))) {
3940                 options->a_prefix = optarg;
3941                 return argcount;
3942         }
3943         else if ((argcount = parse_long_opt("dst-prefix", av, &optarg))) {
3944                 options->b_prefix = optarg;
3945                 return argcount;
3946         }
3947         else if (!strcmp(arg, "--no-prefix"))
3948                 options->a_prefix = options->b_prefix = "";
3949         else if (opt_arg(arg, '\0', "inter-hunk-context",
3950                          &options->interhunkcontext))
3951                 ;
3952         else if (!strcmp(arg, "-W"))
3953                 DIFF_OPT_SET(options, FUNCCONTEXT);
3954         else if (!strcmp(arg, "--function-context"))
3955                 DIFF_OPT_SET(options, FUNCCONTEXT);
3956         else if (!strcmp(arg, "--no-function-context"))
3957                 DIFF_OPT_CLR(options, FUNCCONTEXT);
3958         else if ((argcount = parse_long_opt("output", av, &optarg))) {
3959                 const char *path = prefix_filename(prefix, strlen(prefix), optarg);
3960                 options->file = fopen(path, "w");
3961                 if (!options->file)
3962                         die_errno("Could not open '%s'", path);
3963                 options->close_file = 1;
3964                 return argcount;
3965         } else
3966                 return 0;
3967         return 1;
3968 }
3969
3970 int parse_rename_score(const char **cp_p)
3971 {
3972         unsigned long num, scale;
3973         int ch, dot;
3974         const char *cp = *cp_p;
3975
3976         num = 0;
3977         scale = 1;
3978         dot = 0;
3979         for (;;) {
3980                 ch = *cp;
3981                 if ( !dot && ch == '.' ) {
3982                         scale = 1;
3983                         dot = 1;
3984                 } else if ( ch == '%' ) {
3985                         scale = dot ? scale*100 : 100;
3986                         cp++;   /* % is always at the end */
3987                         break;
3988                 } else if ( ch >= '0' && ch <= '9' ) {
3989                         if ( scale < 100000 ) {
3990                                 scale *= 10;
3991                                 num = (num*10) + (ch-'0');
3992                         }
3993                 } else {
3994                         break;
3995                 }
3996                 cp++;
3997         }
3998         *cp_p = cp;
3999
4000         /* user says num divided by scale and we say internally that
4001          * is MAX_SCORE * num / scale.
4002          */
4003         return (int)((num >= scale) ? MAX_SCORE : (MAX_SCORE * num / scale));
4004 }
4005
4006 static int diff_scoreopt_parse(const char *opt)
4007 {
4008         int opt1, opt2, cmd;
4009
4010         if (*opt++ != '-')
4011                 return -1;
4012         cmd = *opt++;
4013         if (cmd == '-') {
4014                 /* convert the long-form arguments into short-form versions */
4015                 if (skip_prefix(opt, "break-rewrites", &opt)) {
4016                         if (*opt == 0 || *opt++ == '=')
4017                                 cmd = 'B';
4018                 } else if (skip_prefix(opt, "find-copies", &opt)) {
4019                         if (*opt == 0 || *opt++ == '=')
4020                                 cmd = 'C';
4021                 } else if (skip_prefix(opt, "find-renames", &opt)) {
4022                         if (*opt == 0 || *opt++ == '=')
4023                                 cmd = 'M';
4024                 }
4025         }
4026         if (cmd != 'M' && cmd != 'C' && cmd != 'B')
4027                 return -1; /* that is not a -M, -C, or -B option */
4028
4029         opt1 = parse_rename_score(&opt);
4030         if (cmd != 'B')
4031                 opt2 = 0;
4032         else {
4033                 if (*opt == 0)
4034                         opt2 = 0;
4035                 else if (*opt != '/')
4036                         return -1; /* we expect -B80/99 or -B80 */
4037                 else {
4038                         opt++;
4039                         opt2 = parse_rename_score(&opt);
4040                 }
4041         }
4042         if (*opt != 0)
4043                 return -1;
4044         return opt1 | (opt2 << 16);
4045 }
4046
4047 struct diff_queue_struct diff_queued_diff;
4048
4049 void diff_q(struct diff_queue_struct *queue, struct diff_filepair *dp)
4050 {
4051         ALLOC_GROW(queue->queue, queue->nr + 1, queue->alloc);
4052         queue->queue[queue->nr++] = dp;
4053 }
4054
4055 struct diff_filepair *diff_queue(struct diff_queue_struct *queue,
4056                                  struct diff_filespec *one,
4057                                  struct diff_filespec *two)
4058 {
4059         struct diff_filepair *dp = xcalloc(1, sizeof(*dp));
4060         dp->one = one;
4061         dp->two = two;
4062         if (queue)
4063                 diff_q(queue, dp);
4064         return dp;
4065 }
4066
4067 void diff_free_filepair(struct diff_filepair *p)
4068 {
4069         free_filespec(p->one);
4070         free_filespec(p->two);
4071         free(p);
4072 }
4073
4074 /* This is different from find_unique_abbrev() in that
4075  * it stuffs the result with dots for alignment.
4076  */
4077 const char *diff_unique_abbrev(const unsigned char *sha1, int len)
4078 {
4079         int abblen;
4080         const char *abbrev;
4081         if (len == 40)
4082                 return sha1_to_hex(sha1);
4083
4084         abbrev = find_unique_abbrev(sha1, len);
4085         abblen = strlen(abbrev);
4086         if (abblen < 37) {
4087                 static char hex[41];
4088                 if (len < abblen && abblen <= len + 2)
4089                         xsnprintf(hex, sizeof(hex), "%s%.*s", abbrev, len+3-abblen, "..");
4090                 else
4091                         xsnprintf(hex, sizeof(hex), "%s...", abbrev);
4092                 return hex;
4093         }
4094         return sha1_to_hex(sha1);
4095 }
4096
4097 static void diff_flush_raw(struct diff_filepair *p, struct diff_options *opt)
4098 {
4099         int line_termination = opt->line_termination;
4100         int inter_name_termination = line_termination ? '\t' : '\0';
4101
4102         fprintf(opt->file, "%s", diff_line_prefix(opt));
4103         if (!(opt->output_format & DIFF_FORMAT_NAME_STATUS)) {
4104                 fprintf(opt->file, ":%06o %06o %s ", p->one->mode, p->two->mode,
4105                         diff_unique_abbrev(p->one->sha1, opt->abbrev));
4106                 fprintf(opt->file, "%s ", diff_unique_abbrev(p->two->sha1, opt->abbrev));
4107         }
4108         if (p->score) {
4109                 fprintf(opt->file, "%c%03d%c", p->status, similarity_index(p),
4110                         inter_name_termination);
4111         } else {
4112                 fprintf(opt->file, "%c%c", p->status, inter_name_termination);
4113         }
4114
4115         if (p->status == DIFF_STATUS_COPIED ||
4116             p->status == DIFF_STATUS_RENAMED) {
4117                 const char *name_a, *name_b;
4118                 name_a = p->one->path;
4119                 name_b = p->two->path;
4120                 strip_prefix(opt->prefix_length, &name_a, &name_b);
4121                 write_name_quoted(name_a, opt->file, inter_name_termination);
4122                 write_name_quoted(name_b, opt->file, line_termination);
4123         } else {
4124                 const char *name_a, *name_b;
4125                 name_a = p->one->mode ? p->one->path : p->two->path;
4126                 name_b = NULL;
4127                 strip_prefix(opt->prefix_length, &name_a, &name_b);
4128                 write_name_quoted(name_a, opt->file, line_termination);
4129         }
4130 }
4131
4132 int diff_unmodified_pair(struct diff_filepair *p)
4133 {
4134         /* This function is written stricter than necessary to support
4135          * the currently implemented transformers, but the idea is to
4136          * let transformers to produce diff_filepairs any way they want,
4137          * and filter and clean them up here before producing the output.
4138          */
4139         struct diff_filespec *one = p->one, *two = p->two;
4140
4141         if (DIFF_PAIR_UNMERGED(p))
4142                 return 0; /* unmerged is interesting */
4143
4144         /* deletion, addition, mode or type change
4145          * and rename are all interesting.
4146          */
4147         if (DIFF_FILE_VALID(one) != DIFF_FILE_VALID(two) ||
4148             DIFF_PAIR_MODE_CHANGED(p) ||
4149             strcmp(one->path, two->path))
4150                 return 0;
4151
4152         /* both are valid and point at the same path.  that is, we are
4153          * dealing with a change.
4154          */
4155         if (one->sha1_valid && two->sha1_valid &&
4156             !hashcmp(one->sha1, two->sha1) &&
4157             !one->dirty_submodule && !two->dirty_submodule)
4158                 return 1; /* no change */
4159         if (!one->sha1_valid && !two->sha1_valid)
4160                 return 1; /* both look at the same file on the filesystem. */
4161         return 0;
4162 }
4163
4164 static void diff_flush_patch(struct diff_filepair *p, struct diff_options *o)
4165 {
4166         if (diff_unmodified_pair(p))
4167                 return;
4168
4169         if ((DIFF_FILE_VALID(p->one) && S_ISDIR(p->one->mode)) ||
4170             (DIFF_FILE_VALID(p->two) && S_ISDIR(p->two->mode)))
4171                 return; /* no tree diffs in patch format */
4172
4173         run_diff(p, o);
4174 }
4175
4176 static void diff_flush_stat(struct diff_filepair *p, struct diff_options *o,
4177                             struct diffstat_t *diffstat)
4178 {
4179         if (diff_unmodified_pair(p))
4180                 return;
4181
4182         if ((DIFF_FILE_VALID(p->one) && S_ISDIR(p->one->mode)) ||
4183             (DIFF_FILE_VALID(p->two) && S_ISDIR(p->two->mode)))
4184                 return; /* no useful stat for tree diffs */
4185
4186         run_diffstat(p, o, diffstat);
4187 }
4188
4189 static void diff_flush_checkdiff(struct diff_filepair *p,
4190                 struct diff_options *o)
4191 {
4192         if (diff_unmodified_pair(p))
4193                 return;
4194
4195         if ((DIFF_FILE_VALID(p->one) && S_ISDIR(p->one->mode)) ||
4196             (DIFF_FILE_VALID(p->two) && S_ISDIR(p->two->mode)))
4197                 return; /* nothing to check in tree diffs */
4198
4199         run_checkdiff(p, o);
4200 }
4201
4202 int diff_queue_is_empty(void)
4203 {
4204         struct diff_queue_struct *q = &diff_queued_diff;
4205         int i;
4206         for (i = 0; i < q->nr; i++)
4207                 if (!diff_unmodified_pair(q->queue[i]))
4208                         return 0;
4209         return 1;
4210 }
4211
4212 #if DIFF_DEBUG
4213 void diff_debug_filespec(struct diff_filespec *s, int x, const char *one)
4214 {
4215         fprintf(stderr, "queue[%d] %s (%s) %s %06o %s\n",
4216                 x, one ? one : "",
4217                 s->path,
4218                 DIFF_FILE_VALID(s) ? "valid" : "invalid",
4219                 s->mode,
4220                 s->sha1_valid ? sha1_to_hex(s->sha1) : "");
4221         fprintf(stderr, "queue[%d] %s size %lu\n",
4222                 x, one ? one : "",
4223                 s->size);
4224 }
4225
4226 void diff_debug_filepair(const struct diff_filepair *p, int i)
4227 {
4228         diff_debug_filespec(p->one, i, "one");
4229         diff_debug_filespec(p->two, i, "two");
4230         fprintf(stderr, "score %d, status %c rename_used %d broken %d\n",
4231                 p->score, p->status ? p->status : '?',
4232                 p->one->rename_used, p->broken_pair);
4233 }
4234
4235 void diff_debug_queue(const char *msg, struct diff_queue_struct *q)
4236 {
4237         int i;
4238         if (msg)
4239                 fprintf(stderr, "%s\n", msg);
4240         fprintf(stderr, "q->nr = %d\n", q->nr);
4241         for (i = 0; i < q->nr; i++) {
4242                 struct diff_filepair *p = q->queue[i];
4243                 diff_debug_filepair(p, i);
4244         }
4245 }
4246 #endif
4247
4248 static void diff_resolve_rename_copy(void)
4249 {
4250         int i;
4251         struct diff_filepair *p;
4252         struct diff_queue_struct *q = &diff_queued_diff;
4253
4254         diff_debug_queue("resolve-rename-copy", q);
4255
4256         for (i = 0; i < q->nr; i++) {
4257                 p = q->queue[i];
4258                 p->status = 0; /* undecided */
4259                 if (DIFF_PAIR_UNMERGED(p))
4260                         p->status = DIFF_STATUS_UNMERGED;
4261                 else if (!DIFF_FILE_VALID(p->one))
4262                         p->status = DIFF_STATUS_ADDED;
4263                 else if (!DIFF_FILE_VALID(p->two))
4264                         p->status = DIFF_STATUS_DELETED;
4265                 else if (DIFF_PAIR_TYPE_CHANGED(p))
4266                         p->status = DIFF_STATUS_TYPE_CHANGED;
4267
4268                 /* from this point on, we are dealing with a pair
4269                  * whose both sides are valid and of the same type, i.e.
4270                  * either in-place edit or rename/copy edit.
4271                  */
4272                 else if (DIFF_PAIR_RENAME(p)) {
4273                         /*
4274                          * A rename might have re-connected a broken
4275                          * pair up, causing the pathnames to be the
4276                          * same again. If so, that's not a rename at
4277                          * all, just a modification..
4278                          *
4279                          * Otherwise, see if this source was used for
4280                          * multiple renames, in which case we decrement
4281                          * the count, and call it a copy.
4282                          */
4283                         if (!strcmp(p->one->path, p->two->path))
4284                                 p->status = DIFF_STATUS_MODIFIED;
4285                         else if (--p->one->rename_used > 0)
4286                                 p->status = DIFF_STATUS_COPIED;
4287                         else
4288                                 p->status = DIFF_STATUS_RENAMED;
4289                 }
4290                 else if (hashcmp(p->one->sha1, p->two->sha1) ||
4291                          p->one->mode != p->two->mode ||
4292                          p->one->dirty_submodule ||
4293                          p->two->dirty_submodule ||
4294                          is_null_sha1(p->one->sha1))
4295                         p->status = DIFF_STATUS_MODIFIED;
4296                 else {
4297                         /* This is a "no-change" entry and should not
4298                          * happen anymore, but prepare for broken callers.
4299                          */
4300                         error("feeding unmodified %s to diffcore",
4301                               p->one->path);
4302                         p->status = DIFF_STATUS_UNKNOWN;
4303                 }
4304         }
4305         diff_debug_queue("resolve-rename-copy done", q);
4306 }
4307
4308 static int check_pair_status(struct diff_filepair *p)
4309 {
4310         switch (p->status) {
4311         case DIFF_STATUS_UNKNOWN:
4312                 return 0;
4313         case 0:
4314                 die("internal error in diff-resolve-rename-copy");
4315         default:
4316                 return 1;
4317         }
4318 }
4319
4320 static void flush_one_pair(struct diff_filepair *p, struct diff_options *opt)
4321 {
4322         int fmt = opt->output_format;
4323
4324         if (fmt & DIFF_FORMAT_CHECKDIFF)
4325                 diff_flush_checkdiff(p, opt);
4326         else if (fmt & (DIFF_FORMAT_RAW | DIFF_FORMAT_NAME_STATUS))
4327                 diff_flush_raw(p, opt);
4328         else if (fmt & DIFF_FORMAT_NAME) {
4329                 const char *name_a, *name_b;
4330                 name_a = p->two->path;
4331                 name_b = NULL;
4332                 strip_prefix(opt->prefix_length, &name_a, &name_b);
4333                 write_name_quoted(name_a, opt->file, opt->line_termination);
4334         }
4335 }
4336
4337 static void show_file_mode_name(FILE *file, const char *newdelete, struct diff_filespec *fs)
4338 {
4339         if (fs->mode)
4340                 fprintf(file, " %s mode %06o ", newdelete, fs->mode);
4341         else
4342                 fprintf(file, " %s ", newdelete);
4343         write_name_quoted(fs->path, file, '\n');
4344 }
4345
4346
4347 static void show_mode_change(FILE *file, struct diff_filepair *p, int show_name,
4348                 const char *line_prefix)
4349 {
4350         if (p->one->mode && p->two->mode && p->one->mode != p->two->mode) {
4351                 fprintf(file, "%s mode change %06o => %06o%c", line_prefix, p->one->mode,
4352                         p->two->mode, show_name ? ' ' : '\n');
4353                 if (show_name) {
4354                         write_name_quoted(p->two->path, file, '\n');
4355                 }
4356         }
4357 }
4358
4359 static void show_rename_copy(FILE *file, const char *renamecopy, struct diff_filepair *p,
4360                         const char *line_prefix)
4361 {
4362         char *names = pprint_rename(p->one->path, p->two->path);
4363
4364         fprintf(file, " %s %s (%d%%)\n", renamecopy, names, similarity_index(p));
4365         free(names);
4366         show_mode_change(file, p, 0, line_prefix);
4367 }
4368
4369 static void diff_summary(struct diff_options *opt, struct diff_filepair *p)
4370 {
4371         FILE *file = opt->file;
4372         const char *line_prefix = diff_line_prefix(opt);
4373
4374         switch(p->status) {
4375         case DIFF_STATUS_DELETED:
4376                 fputs(line_prefix, file);
4377                 show_file_mode_name(file, "delete", p->one);
4378                 break;
4379         case DIFF_STATUS_ADDED:
4380                 fputs(line_prefix, file);
4381                 show_file_mode_name(file, "create", p->two);
4382                 break;
4383         case DIFF_STATUS_COPIED:
4384                 fputs(line_prefix, file);
4385                 show_rename_copy(file, "copy", p, line_prefix);
4386                 break;
4387         case DIFF_STATUS_RENAMED:
4388                 fputs(line_prefix, file);
4389                 show_rename_copy(file, "rename", p, line_prefix);
4390                 break;
4391         default:
4392                 if (p->score) {
4393                         fprintf(file, "%s rewrite ", line_prefix);
4394                         write_name_quoted(p->two->path, file, ' ');
4395                         fprintf(file, "(%d%%)\n", similarity_index(p));
4396                 }
4397                 show_mode_change(file, p, !p->score, line_prefix);
4398                 break;
4399         }
4400 }
4401
4402 struct patch_id_t {
4403         git_SHA_CTX *ctx;
4404         int patchlen;
4405 };
4406
4407 static int remove_space(char *line, int len)
4408 {
4409         int i;
4410         char *dst = line;
4411         unsigned char c;
4412
4413         for (i = 0; i < len; i++)
4414                 if (!isspace((c = line[i])))
4415                         *dst++ = c;
4416
4417         return dst - line;
4418 }
4419
4420 static void patch_id_consume(void *priv, char *line, unsigned long len)
4421 {
4422         struct patch_id_t *data = priv;
4423         int new_len;
4424
4425         /* Ignore line numbers when computing the SHA1 of the patch */
4426         if (starts_with(line, "@@ -"))
4427                 return;
4428
4429         new_len = remove_space(line, len);
4430
4431         git_SHA1_Update(data->ctx, line, new_len);
4432         data->patchlen += new_len;
4433 }
4434
4435 /* returns 0 upon success, and writes result into sha1 */
4436 static int diff_get_patch_id(struct diff_options *options, unsigned char *sha1)
4437 {
4438         struct diff_queue_struct *q = &diff_queued_diff;
4439         int i;
4440         git_SHA_CTX ctx;
4441         struct patch_id_t data;
4442         char buffer[PATH_MAX * 4 + 20];
4443
4444         git_SHA1_Init(&ctx);
4445         memset(&data, 0, sizeof(struct patch_id_t));
4446         data.ctx = &ctx;
4447
4448         for (i = 0; i < q->nr; i++) {
4449                 xpparam_t xpp;
4450                 xdemitconf_t xecfg;
4451                 mmfile_t mf1, mf2;
4452                 struct diff_filepair *p = q->queue[i];
4453                 int len1, len2;
4454
4455                 memset(&xpp, 0, sizeof(xpp));
4456                 memset(&xecfg, 0, sizeof(xecfg));
4457                 if (p->status == 0)
4458                         return error("internal diff status error");
4459                 if (p->status == DIFF_STATUS_UNKNOWN)
4460                         continue;
4461                 if (diff_unmodified_pair(p))
4462                         continue;
4463                 if ((DIFF_FILE_VALID(p->one) && S_ISDIR(p->one->mode)) ||
4464                     (DIFF_FILE_VALID(p->two) && S_ISDIR(p->two->mode)))
4465                         continue;
4466                 if (DIFF_PAIR_UNMERGED(p))
4467                         continue;
4468
4469                 diff_fill_sha1_info(p->one);
4470                 diff_fill_sha1_info(p->two);
4471                 if (fill_mmfile(&mf1, p->one) < 0 ||
4472                                 fill_mmfile(&mf2, p->two) < 0)
4473                         return error("unable to read files to diff");
4474
4475                 len1 = remove_space(p->one->path, strlen(p->one->path));
4476                 len2 = remove_space(p->two->path, strlen(p->two->path));
4477                 if (p->one->mode == 0)
4478                         len1 = snprintf(buffer, sizeof(buffer),
4479                                         "diff--gita/%.*sb/%.*s"
4480                                         "newfilemode%06o"
4481                                         "---/dev/null"
4482                                         "+++b/%.*s",
4483                                         len1, p->one->path,
4484                                         len2, p->two->path,
4485                                         p->two->mode,
4486                                         len2, p->two->path);
4487                 else if (p->two->mode == 0)
4488                         len1 = snprintf(buffer, sizeof(buffer),
4489                                         "diff--gita/%.*sb/%.*s"
4490                                         "deletedfilemode%06o"
4491                                         "---a/%.*s"
4492                                         "+++/dev/null",
4493                                         len1, p->one->path,
4494                                         len2, p->two->path,
4495                                         p->one->mode,
4496                                         len1, p->one->path);
4497                 else
4498                         len1 = snprintf(buffer, sizeof(buffer),
4499                                         "diff--gita/%.*sb/%.*s"
4500                                         "---a/%.*s"
4501                                         "+++b/%.*s",
4502                                         len1, p->one->path,
4503                                         len2, p->two->path,
4504                                         len1, p->one->path,
4505                                         len2, p->two->path);
4506                 git_SHA1_Update(&ctx, buffer, len1);
4507
4508                 if (diff_filespec_is_binary(p->one) ||
4509                     diff_filespec_is_binary(p->two)) {
4510                         git_SHA1_Update(&ctx, sha1_to_hex(p->one->sha1), 40);
4511                         git_SHA1_Update(&ctx, sha1_to_hex(p->two->sha1), 40);
4512                         continue;
4513                 }
4514
4515                 xpp.flags = 0;
4516                 xecfg.ctxlen = 3;
4517                 xecfg.flags = 0;
4518                 if (xdi_diff_outf(&mf1, &mf2, patch_id_consume, &data,
4519                                   &xpp, &xecfg))
4520                         return error("unable to generate patch-id diff for %s",
4521                                      p->one->path);
4522         }
4523
4524         git_SHA1_Final(sha1, &ctx);
4525         return 0;
4526 }
4527
4528 int diff_flush_patch_id(struct diff_options *options, unsigned char *sha1)
4529 {
4530         struct diff_queue_struct *q = &diff_queued_diff;
4531         int i;
4532         int result = diff_get_patch_id(options, sha1);
4533
4534         for (i = 0; i < q->nr; i++)
4535                 diff_free_filepair(q->queue[i]);
4536
4537         free(q->queue);
4538         DIFF_QUEUE_CLEAR(q);
4539
4540         return result;
4541 }
4542
4543 static int is_summary_empty(const struct diff_queue_struct *q)
4544 {
4545         int i;
4546
4547         for (i = 0; i < q->nr; i++) {
4548                 const struct diff_filepair *p = q->queue[i];
4549
4550                 switch (p->status) {
4551                 case DIFF_STATUS_DELETED:
4552                 case DIFF_STATUS_ADDED:
4553                 case DIFF_STATUS_COPIED:
4554                 case DIFF_STATUS_RENAMED:
4555                         return 0;
4556                 default:
4557                         if (p->score)
4558                                 return 0;
4559                         if (p->one->mode && p->two->mode &&
4560                             p->one->mode != p->two->mode)
4561                                 return 0;
4562                         break;
4563                 }
4564         }
4565         return 1;
4566 }
4567
4568 static const char rename_limit_warning[] =
4569 "inexact rename detection was skipped due to too many files.";
4570
4571 static const char degrade_cc_to_c_warning[] =
4572 "only found copies from modified paths due to too many files.";
4573
4574 static const char rename_limit_advice[] =
4575 "you may want to set your %s variable to at least "
4576 "%d and retry the command.";
4577
4578 void diff_warn_rename_limit(const char *varname, int needed, int degraded_cc)
4579 {
4580         if (degraded_cc)
4581                 warning(degrade_cc_to_c_warning);
4582         else if (needed)
4583                 warning(rename_limit_warning);
4584         else
4585                 return;
4586         if (0 < needed && needed < 32767)
4587                 warning(rename_limit_advice, varname, needed);
4588 }
4589
4590 void diff_flush(struct diff_options *options)
4591 {
4592         struct diff_queue_struct *q = &diff_queued_diff;
4593         int i, output_format = options->output_format;
4594         int separator = 0;
4595         int dirstat_by_line = 0;
4596
4597         /*
4598          * Order: raw, stat, summary, patch
4599          * or:    name/name-status/checkdiff (other bits clear)
4600          */
4601         if (!q->nr)
4602                 goto free_queue;
4603
4604         if (output_format & (DIFF_FORMAT_RAW |
4605                              DIFF_FORMAT_NAME |
4606                              DIFF_FORMAT_NAME_STATUS |
4607                              DIFF_FORMAT_CHECKDIFF)) {
4608                 for (i = 0; i < q->nr; i++) {
4609                         struct diff_filepair *p = q->queue[i];
4610                         if (check_pair_status(p))
4611                                 flush_one_pair(p, options);
4612                 }
4613                 separator++;
4614         }
4615
4616         if (output_format & DIFF_FORMAT_DIRSTAT && DIFF_OPT_TST(options, DIRSTAT_BY_LINE))
4617                 dirstat_by_line = 1;
4618
4619         if (output_format & (DIFF_FORMAT_DIFFSTAT|DIFF_FORMAT_SHORTSTAT|DIFF_FORMAT_NUMSTAT) ||
4620             dirstat_by_line) {
4621                 struct diffstat_t diffstat;
4622
4623                 memset(&diffstat, 0, sizeof(struct diffstat_t));
4624                 for (i = 0; i < q->nr; i++) {
4625                         struct diff_filepair *p = q->queue[i];
4626                         if (check_pair_status(p))
4627                                 diff_flush_stat(p, options, &diffstat);
4628                 }
4629                 if (output_format & DIFF_FORMAT_NUMSTAT)
4630                         show_numstat(&diffstat, options);
4631                 if (output_format & DIFF_FORMAT_DIFFSTAT)
4632                         show_stats(&diffstat, options);
4633                 if (output_format & DIFF_FORMAT_SHORTSTAT)
4634                         show_shortstats(&diffstat, options);
4635                 if (output_format & DIFF_FORMAT_DIRSTAT && dirstat_by_line)
4636                         show_dirstat_by_line(&diffstat, options);
4637                 free_diffstat_info(&diffstat);
4638                 separator++;
4639         }
4640         if ((output_format & DIFF_FORMAT_DIRSTAT) && !dirstat_by_line)
4641                 show_dirstat(options);
4642
4643         if (output_format & DIFF_FORMAT_SUMMARY && !is_summary_empty(q)) {
4644                 for (i = 0; i < q->nr; i++) {
4645                         diff_summary(options, q->queue[i]);
4646                 }
4647                 separator++;
4648         }
4649
4650         if (output_format & DIFF_FORMAT_NO_OUTPUT &&
4651             DIFF_OPT_TST(options, EXIT_WITH_STATUS) &&
4652             DIFF_OPT_TST(options, DIFF_FROM_CONTENTS)) {
4653                 /*
4654                  * run diff_flush_patch for the exit status. setting
4655                  * options->file to /dev/null should be safe, because we
4656                  * aren't supposed to produce any output anyway.
4657                  */
4658                 if (options->close_file)
4659                         fclose(options->file);
4660                 options->file = fopen("/dev/null", "w");
4661                 if (!options->file)
4662                         die_errno("Could not open /dev/null");
4663                 options->close_file = 1;
4664                 for (i = 0; i < q->nr; i++) {
4665                         struct diff_filepair *p = q->queue[i];
4666                         if (check_pair_status(p))
4667                                 diff_flush_patch(p, options);
4668                         if (options->found_changes)
4669                                 break;
4670                 }
4671         }
4672
4673         if (output_format & DIFF_FORMAT_PATCH) {
4674                 if (separator) {
4675                         fprintf(options->file, "%s%c",
4676                                 diff_line_prefix(options),
4677                                 options->line_termination);
4678                         if (options->stat_sep) {
4679                                 /* attach patch instead of inline */
4680                                 fputs(options->stat_sep, options->file);
4681                         }
4682                 }
4683
4684                 for (i = 0; i < q->nr; i++) {
4685                         struct diff_filepair *p = q->queue[i];
4686                         if (check_pair_status(p))
4687                                 diff_flush_patch(p, options);
4688                 }
4689         }
4690
4691         if (output_format & DIFF_FORMAT_CALLBACK)
4692                 options->format_callback(q, options, options->format_callback_data);
4693
4694         for (i = 0; i < q->nr; i++)
4695                 diff_free_filepair(q->queue[i]);
4696 free_queue:
4697         free(q->queue);
4698         DIFF_QUEUE_CLEAR(q);
4699         if (options->close_file)
4700                 fclose(options->file);
4701
4702         /*
4703          * Report the content-level differences with HAS_CHANGES;
4704          * diff_addremove/diff_change does not set the bit when
4705          * DIFF_FROM_CONTENTS is in effect (e.g. with -w).
4706          */
4707         if (DIFF_OPT_TST(options, DIFF_FROM_CONTENTS)) {
4708                 if (options->found_changes)
4709                         DIFF_OPT_SET(options, HAS_CHANGES);
4710                 else
4711                         DIFF_OPT_CLR(options, HAS_CHANGES);
4712         }
4713 }
4714
4715 static int match_filter(const struct diff_options *options, const struct diff_filepair *p)
4716 {
4717         return (((p->status == DIFF_STATUS_MODIFIED) &&
4718                  ((p->score &&
4719                    filter_bit_tst(DIFF_STATUS_FILTER_BROKEN, options)) ||
4720                   (!p->score &&
4721                    filter_bit_tst(DIFF_STATUS_MODIFIED, options)))) ||
4722                 ((p->status != DIFF_STATUS_MODIFIED) &&
4723                  filter_bit_tst(p->status, options)));
4724 }
4725
4726 static void diffcore_apply_filter(struct diff_options *options)
4727 {
4728         int i;
4729         struct diff_queue_struct *q = &diff_queued_diff;
4730         struct diff_queue_struct outq;
4731
4732         DIFF_QUEUE_CLEAR(&outq);
4733
4734         if (!options->filter)
4735                 return;
4736
4737         if (filter_bit_tst(DIFF_STATUS_FILTER_AON, options)) {
4738                 int found;
4739                 for (i = found = 0; !found && i < q->nr; i++) {
4740                         if (match_filter(options, q->queue[i]))
4741                                 found++;
4742                 }
4743                 if (found)
4744                         return;
4745
4746                 /* otherwise we will clear the whole queue
4747                  * by copying the empty outq at the end of this
4748                  * function, but first clear the current entries
4749                  * in the queue.
4750                  */
4751                 for (i = 0; i < q->nr; i++)
4752                         diff_free_filepair(q->queue[i]);
4753         }
4754         else {
4755                 /* Only the matching ones */
4756                 for (i = 0; i < q->nr; i++) {
4757                         struct diff_filepair *p = q->queue[i];
4758                         if (match_filter(options, p))
4759                                 diff_q(&outq, p);
4760                         else
4761                                 diff_free_filepair(p);
4762                 }
4763         }
4764         free(q->queue);
4765         *q = outq;
4766 }
4767
4768 /* Check whether two filespecs with the same mode and size are identical */
4769 static int diff_filespec_is_identical(struct diff_filespec *one,
4770                                       struct diff_filespec *two)
4771 {
4772         if (S_ISGITLINK(one->mode))
4773                 return 0;
4774         if (diff_populate_filespec(one, 0))
4775                 return 0;
4776         if (diff_populate_filespec(two, 0))
4777                 return 0;
4778         return !memcmp(one->data, two->data, one->size);
4779 }
4780
4781 static int diff_filespec_check_stat_unmatch(struct diff_filepair *p)
4782 {
4783         if (p->done_skip_stat_unmatch)
4784                 return p->skip_stat_unmatch_result;
4785
4786         p->done_skip_stat_unmatch = 1;
4787         p->skip_stat_unmatch_result = 0;
4788         /*
4789          * 1. Entries that come from stat info dirtiness
4790          *    always have both sides (iow, not create/delete),
4791          *    one side of the object name is unknown, with
4792          *    the same mode and size.  Keep the ones that
4793          *    do not match these criteria.  They have real
4794          *    differences.
4795          *
4796          * 2. At this point, the file is known to be modified,
4797          *    with the same mode and size, and the object
4798          *    name of one side is unknown.  Need to inspect
4799          *    the identical contents.
4800          */
4801         if (!DIFF_FILE_VALID(p->one) || /* (1) */
4802             !DIFF_FILE_VALID(p->two) ||
4803             (p->one->sha1_valid && p->two->sha1_valid) ||
4804             (p->one->mode != p->two->mode) ||
4805             diff_populate_filespec(p->one, CHECK_SIZE_ONLY) ||
4806             diff_populate_filespec(p->two, CHECK_SIZE_ONLY) ||
4807             (p->one->size != p->two->size) ||
4808             !diff_filespec_is_identical(p->one, p->two)) /* (2) */
4809                 p->skip_stat_unmatch_result = 1;
4810         return p->skip_stat_unmatch_result;
4811 }
4812
4813 static void diffcore_skip_stat_unmatch(struct diff_options *diffopt)
4814 {
4815         int i;
4816         struct diff_queue_struct *q = &diff_queued_diff;
4817         struct diff_queue_struct outq;
4818         DIFF_QUEUE_CLEAR(&outq);
4819
4820         for (i = 0; i < q->nr; i++) {
4821                 struct diff_filepair *p = q->queue[i];
4822
4823                 if (diff_filespec_check_stat_unmatch(p))
4824                         diff_q(&outq, p);
4825                 else {
4826                         /*
4827                          * The caller can subtract 1 from skip_stat_unmatch
4828                          * to determine how many paths were dirty only
4829                          * due to stat info mismatch.
4830                          */
4831                         if (!DIFF_OPT_TST(diffopt, NO_INDEX))
4832                                 diffopt->skip_stat_unmatch++;
4833                         diff_free_filepair(p);
4834                 }
4835         }
4836         free(q->queue);
4837         *q = outq;
4838 }
4839
4840 static int diffnamecmp(const void *a_, const void *b_)
4841 {
4842         const struct diff_filepair *a = *((const struct diff_filepair **)a_);
4843         const struct diff_filepair *b = *((const struct diff_filepair **)b_);
4844         const char *name_a, *name_b;
4845
4846         name_a = a->one ? a->one->path : a->two->path;
4847         name_b = b->one ? b->one->path : b->two->path;
4848         return strcmp(name_a, name_b);
4849 }
4850
4851 void diffcore_fix_diff_index(struct diff_options *options)
4852 {
4853         struct diff_queue_struct *q = &diff_queued_diff;
4854         qsort(q->queue, q->nr, sizeof(q->queue[0]), diffnamecmp);
4855 }
4856
4857 void diffcore_std(struct diff_options *options)
4858 {
4859         /* NOTE please keep the following in sync with diff_tree_combined() */
4860         if (options->skip_stat_unmatch)
4861                 diffcore_skip_stat_unmatch(options);
4862         if (!options->found_follow) {
4863                 /* See try_to_follow_renames() in tree-diff.c */
4864                 if (options->break_opt != -1)
4865                         diffcore_break(options->break_opt);
4866                 if (options->detect_rename)
4867                         diffcore_rename(options);
4868                 if (options->break_opt != -1)
4869                         diffcore_merge_broken();
4870         }
4871         if (options->pickaxe)
4872                 diffcore_pickaxe(options);
4873         if (options->orderfile)
4874                 diffcore_order(options->orderfile);
4875         if (!options->found_follow)
4876                 /* See try_to_follow_renames() in tree-diff.c */
4877                 diff_resolve_rename_copy();
4878         diffcore_apply_filter(options);
4879
4880         if (diff_queued_diff.nr && !DIFF_OPT_TST(options, DIFF_FROM_CONTENTS))
4881                 DIFF_OPT_SET(options, HAS_CHANGES);
4882         else
4883                 DIFF_OPT_CLR(options, HAS_CHANGES);
4884
4885         options->found_follow = 0;
4886 }
4887
4888 int diff_result_code(struct diff_options *opt, int status)
4889 {
4890         int result = 0;
4891
4892         diff_warn_rename_limit("diff.renameLimit",
4893                                opt->needed_rename_limit,
4894                                opt->degraded_cc_to_c);
4895         if (!DIFF_OPT_TST(opt, EXIT_WITH_STATUS) &&
4896             !(opt->output_format & DIFF_FORMAT_CHECKDIFF))
4897                 return status;
4898         if (DIFF_OPT_TST(opt, EXIT_WITH_STATUS) &&
4899             DIFF_OPT_TST(opt, HAS_CHANGES))
4900                 result |= 01;
4901         if ((opt->output_format & DIFF_FORMAT_CHECKDIFF) &&
4902             DIFF_OPT_TST(opt, CHECK_FAILED))
4903                 result |= 02;
4904         return result;
4905 }
4906
4907 int diff_can_quit_early(struct diff_options *opt)
4908 {
4909         return (DIFF_OPT_TST(opt, QUICK) &&
4910                 !opt->filter &&
4911                 DIFF_OPT_TST(opt, HAS_CHANGES));
4912 }
4913
4914 /*
4915  * Shall changes to this submodule be ignored?
4916  *
4917  * Submodule changes can be configured to be ignored separately for each path,
4918  * but that configuration can be overridden from the command line.
4919  */
4920 static int is_submodule_ignored(const char *path, struct diff_options *options)
4921 {
4922         int ignored = 0;
4923         unsigned orig_flags = options->flags;
4924         if (!DIFF_OPT_TST(options, OVERRIDE_SUBMODULE_CONFIG))
4925                 set_diffopt_flags_from_submodule_config(options, path);
4926         if (DIFF_OPT_TST(options, IGNORE_SUBMODULES))
4927                 ignored = 1;
4928         options->flags = orig_flags;
4929         return ignored;
4930 }
4931
4932 void diff_addremove(struct diff_options *options,
4933                     int addremove, unsigned mode,
4934                     const unsigned char *sha1,
4935                     int sha1_valid,
4936                     const char *concatpath, unsigned dirty_submodule)
4937 {
4938         struct diff_filespec *one, *two;
4939
4940         if (S_ISGITLINK(mode) && is_submodule_ignored(concatpath, options))
4941                 return;
4942
4943         /* This may look odd, but it is a preparation for
4944          * feeding "there are unchanged files which should
4945          * not produce diffs, but when you are doing copy
4946          * detection you would need them, so here they are"
4947          * entries to the diff-core.  They will be prefixed
4948          * with something like '=' or '*' (I haven't decided
4949          * which but should not make any difference).
4950          * Feeding the same new and old to diff_change()
4951          * also has the same effect.
4952          * Before the final output happens, they are pruned after
4953          * merged into rename/copy pairs as appropriate.
4954          */
4955         if (DIFF_OPT_TST(options, REVERSE_DIFF))
4956                 addremove = (addremove == '+' ? '-' :
4957                              addremove == '-' ? '+' : addremove);
4958
4959         if (options->prefix &&
4960             strncmp(concatpath, options->prefix, options->prefix_length))
4961                 return;
4962
4963         one = alloc_filespec(concatpath);
4964         two = alloc_filespec(concatpath);
4965
4966         if (addremove != '+')
4967                 fill_filespec(one, sha1, sha1_valid, mode);
4968         if (addremove != '-') {
4969                 fill_filespec(two, sha1, sha1_valid, mode);
4970                 two->dirty_submodule = dirty_submodule;
4971         }
4972
4973         diff_queue(&diff_queued_diff, one, two);
4974         if (!DIFF_OPT_TST(options, DIFF_FROM_CONTENTS))
4975                 DIFF_OPT_SET(options, HAS_CHANGES);
4976 }
4977
4978 void diff_change(struct diff_options *options,
4979                  unsigned old_mode, unsigned new_mode,
4980                  const unsigned char *old_sha1,
4981                  const unsigned char *new_sha1,
4982                  int old_sha1_valid, int new_sha1_valid,
4983                  const char *concatpath,
4984                  unsigned old_dirty_submodule, unsigned new_dirty_submodule)
4985 {
4986         struct diff_filespec *one, *two;
4987         struct diff_filepair *p;
4988
4989         if (S_ISGITLINK(old_mode) && S_ISGITLINK(new_mode) &&
4990             is_submodule_ignored(concatpath, options))
4991                 return;
4992
4993         if (DIFF_OPT_TST(options, REVERSE_DIFF)) {
4994                 unsigned tmp;
4995                 const unsigned char *tmp_c;
4996                 tmp = old_mode; old_mode = new_mode; new_mode = tmp;
4997                 tmp_c = old_sha1; old_sha1 = new_sha1; new_sha1 = tmp_c;
4998                 tmp = old_sha1_valid; old_sha1_valid = new_sha1_valid;
4999                         new_sha1_valid = tmp;
5000                 tmp = old_dirty_submodule; old_dirty_submodule = new_dirty_submodule;
5001                         new_dirty_submodule = tmp;
5002         }
5003
5004         if (options->prefix &&
5005             strncmp(concatpath, options->prefix, options->prefix_length))
5006                 return;
5007
5008         one = alloc_filespec(concatpath);
5009         two = alloc_filespec(concatpath);
5010         fill_filespec(one, old_sha1, old_sha1_valid, old_mode);
5011         fill_filespec(two, new_sha1, new_sha1_valid, new_mode);
5012         one->dirty_submodule = old_dirty_submodule;
5013         two->dirty_submodule = new_dirty_submodule;
5014         p = diff_queue(&diff_queued_diff, one, two);
5015
5016         if (DIFF_OPT_TST(options, DIFF_FROM_CONTENTS))
5017                 return;
5018
5019         if (DIFF_OPT_TST(options, QUICK) && options->skip_stat_unmatch &&
5020             !diff_filespec_check_stat_unmatch(p))
5021                 return;
5022
5023         DIFF_OPT_SET(options, HAS_CHANGES);
5024 }
5025
5026 struct diff_filepair *diff_unmerge(struct diff_options *options, const char *path)
5027 {
5028         struct diff_filepair *pair;
5029         struct diff_filespec *one, *two;
5030
5031         if (options->prefix &&
5032             strncmp(path, options->prefix, options->prefix_length))
5033                 return NULL;
5034
5035         one = alloc_filespec(path);
5036         two = alloc_filespec(path);
5037         pair = diff_queue(&diff_queued_diff, one, two);
5038         pair->is_unmerged = 1;
5039         return pair;
5040 }
5041
5042 static char *run_textconv(const char *pgm, struct diff_filespec *spec,
5043                 size_t *outsize)
5044 {
5045         struct diff_tempfile *temp;
5046         const char *argv[3];
5047         const char **arg = argv;
5048         struct child_process child = CHILD_PROCESS_INIT;
5049         struct strbuf buf = STRBUF_INIT;
5050         int err = 0;
5051
5052         temp = prepare_temp_file(spec->path, spec);
5053         *arg++ = pgm;
5054         *arg++ = temp->name;
5055         *arg = NULL;
5056
5057         child.use_shell = 1;
5058         child.argv = argv;
5059         child.out = -1;
5060         if (start_command(&child)) {
5061                 remove_tempfile();
5062                 return NULL;
5063         }
5064
5065         if (strbuf_read(&buf, child.out, 0) < 0)
5066                 err = error("error reading from textconv command '%s'", pgm);
5067         close(child.out);
5068
5069         if (finish_command(&child) || err) {
5070                 strbuf_release(&buf);
5071                 remove_tempfile();
5072                 return NULL;
5073         }
5074         remove_tempfile();
5075
5076         return strbuf_detach(&buf, outsize);
5077 }
5078
5079 size_t fill_textconv(struct userdiff_driver *driver,
5080                      struct diff_filespec *df,
5081                      char **outbuf)
5082 {
5083         size_t size;
5084
5085         if (!driver) {
5086                 if (!DIFF_FILE_VALID(df)) {
5087                         *outbuf = "";
5088                         return 0;
5089                 }
5090                 if (diff_populate_filespec(df, 0))
5091                         die("unable to read files to diff");
5092                 *outbuf = df->data;
5093                 return df->size;
5094         }
5095
5096         if (!driver->textconv)
5097                 die("BUG: fill_textconv called with non-textconv driver");
5098
5099         if (driver->textconv_cache && df->sha1_valid) {
5100                 *outbuf = notes_cache_get(driver->textconv_cache, df->sha1,
5101                                           &size);
5102                 if (*outbuf)
5103                         return size;
5104         }
5105
5106         *outbuf = run_textconv(driver->textconv, df, &size);
5107         if (!*outbuf)
5108                 die("unable to read files to diff");
5109
5110         if (driver->textconv_cache && df->sha1_valid) {
5111                 /* ignore errors, as we might be in a readonly repository */
5112                 notes_cache_put(driver->textconv_cache, df->sha1, *outbuf,
5113                                 size);
5114                 /*
5115                  * we could save up changes and flush them all at the end,
5116                  * but we would need an extra call after all diffing is done.
5117                  * Since generating a cache entry is the slow path anyway,
5118                  * this extra overhead probably isn't a big deal.
5119                  */
5120                 notes_cache_write(driver->textconv_cache);
5121         }
5122
5123         return size;
5124 }
5125
5126 void setup_diff_pager(struct diff_options *opt)
5127 {
5128         /*
5129          * If the user asked for our exit code, then either they want --quiet
5130          * or --exit-code. We should definitely not bother with a pager in the
5131          * former case, as we will generate no output. Since we still properly
5132          * report our exit code even when a pager is run, we _could_ run a
5133          * pager with --exit-code. But since we have not done so historically,
5134          * and because it is easy to find people oneline advising "git diff
5135          * --exit-code" in hooks and other scripts, we do not do so.
5136          */
5137         if (!DIFF_OPT_TST(opt, EXIT_WITH_STATUS) &&
5138             check_pager_config("diff") != 0)
5139                 setup_pager();
5140 }