Merge branch 'jc/fmt-patch'
[git] / builtin-grep.c
1 /*
2  * Builtin "git grep"
3  *
4  * Copyright (c) 2006 Junio C Hamano
5  */
6 #include "cache.h"
7 #include "blob.h"
8 #include "tree.h"
9 #include "commit.h"
10 #include "tag.h"
11 #include "tree-walk.h"
12 #include "builtin.h"
13 #include <regex.h>
14 #include <fnmatch.h>
15 #include <sys/wait.h>
16
17 /*
18  * git grep pathspecs are somewhat different from diff-tree pathspecs;
19  * pathname wildcards are allowed.
20  */
21 static int pathspec_matches(const char **paths, const char *name)
22 {
23         int namelen, i;
24         if (!paths || !*paths)
25                 return 1;
26         namelen = strlen(name);
27         for (i = 0; paths[i]; i++) {
28                 const char *match = paths[i];
29                 int matchlen = strlen(match);
30                 const char *cp, *meta;
31
32                 if ((matchlen <= namelen) &&
33                     !strncmp(name, match, matchlen) &&
34                     (match[matchlen-1] == '/' ||
35                      name[matchlen] == '\0' || name[matchlen] == '/'))
36                         return 1;
37                 if (!fnmatch(match, name, 0))
38                         return 1;
39                 if (name[namelen-1] != '/')
40                         continue;
41
42                 /* We are being asked if the directory ("name") is worth
43                  * descending into.
44                  *
45                  * Find the longest leading directory name that does
46                  * not have metacharacter in the pathspec; the name
47                  * we are looking at must overlap with that directory.
48                  */
49                 for (cp = match, meta = NULL; cp - match < matchlen; cp++) {
50                         char ch = *cp;
51                         if (ch == '*' || ch == '[' || ch == '?') {
52                                 meta = cp;
53                                 break;
54                         }
55                 }
56                 if (!meta)
57                         meta = cp; /* fully literal */
58
59                 if (namelen <= meta - match) {
60                         /* Looking at "Documentation/" and
61                          * the pattern says "Documentation/howto/", or
62                          * "Documentation/diff*.txt".  The name we
63                          * have should match prefix.
64                          */
65                         if (!memcmp(match, name, namelen))
66                                 return 1;
67                         continue;
68                 }
69
70                 if (meta - match < namelen) {
71                         /* Looking at "Documentation/howto/" and
72                          * the pattern says "Documentation/h*";
73                          * match up to "Do.../h"; this avoids descending
74                          * into "Documentation/technical/".
75                          */
76                         if (!memcmp(match, name, meta - match))
77                                 return 1;
78                         continue;
79                 }
80         }
81         return 0;
82 }
83
84 struct grep_pat {
85         struct grep_pat *next;
86         const char *origin;
87         int no;
88         const char *pattern;
89         regex_t regexp;
90 };
91
92 struct grep_opt {
93         struct grep_pat *pattern_list;
94         struct grep_pat **pattern_tail;
95         regex_t regexp;
96         unsigned linenum:1;
97         unsigned invert:1;
98         unsigned name_only:1;
99         unsigned unmatch_name_only:1;
100         unsigned count:1;
101         unsigned word_regexp:1;
102         unsigned fixed:1;
103 #define GREP_BINARY_DEFAULT     0
104 #define GREP_BINARY_NOMATCH     1
105 #define GREP_BINARY_TEXT        2
106         unsigned binary:2;
107         int regflags;
108         unsigned pre_context;
109         unsigned post_context;
110 };
111
112 static void add_pattern(struct grep_opt *opt, const char *pat,
113                         const char *origin, int no)
114 {
115         struct grep_pat *p = xcalloc(1, sizeof(*p));
116         p->pattern = pat;
117         p->origin = origin;
118         p->no = no;
119         *opt->pattern_tail = p;
120         opt->pattern_tail = &p->next;
121         p->next = NULL;
122 }
123
124 static void compile_patterns(struct grep_opt *opt)
125 {
126         struct grep_pat *p;
127         for (p = opt->pattern_list; p; p = p->next) {
128                 int err = regcomp(&p->regexp, p->pattern, opt->regflags);
129                 if (err) {
130                         char errbuf[1024];
131                         char where[1024];
132                         if (p->no)
133                                 sprintf(where, "In '%s' at %d, ",
134                                         p->origin, p->no);
135                         else if (p->origin)
136                                 sprintf(where, "%s, ", p->origin);
137                         else
138                                 where[0] = 0;
139                         regerror(err, &p->regexp, errbuf, 1024);
140                         regfree(&p->regexp);
141                         die("%s'%s': %s", where, p->pattern, errbuf);
142                 }
143         }
144 }
145
146 static char *end_of_line(char *cp, unsigned long *left)
147 {
148         unsigned long l = *left;
149         while (l && *cp != '\n') {
150                 l--;
151                 cp++;
152         }
153         *left = l;
154         return cp;
155 }
156
157 static int word_char(char ch)
158 {
159         return isalnum(ch) || ch == '_';
160 }
161
162 static void show_line(struct grep_opt *opt, const char *bol, const char *eol,
163                       const char *name, unsigned lno, char sign)
164 {
165         printf("%s%c", name, sign);
166         if (opt->linenum)
167                 printf("%d%c", lno, sign);
168         printf("%.*s\n", (int)(eol-bol), bol);
169 }
170
171 /*
172  * NEEDSWORK: share code with diff.c
173  */
174 #define FIRST_FEW_BYTES 8000
175 static int buffer_is_binary(const char *ptr, unsigned long size)
176 {
177         if (FIRST_FEW_BYTES < size)
178                 size = FIRST_FEW_BYTES;
179         if (memchr(ptr, 0, size))
180                 return 1;
181         return 0;
182 }
183
184 static int fixmatch(const char *pattern, char *line, regmatch_t *match)
185 {
186         char *hit = strstr(line, pattern);
187         if (!hit) {
188                 match->rm_so = match->rm_eo = -1;
189                 return REG_NOMATCH;
190         }
191         else {
192                 match->rm_so = hit - line;
193                 match->rm_eo = match->rm_so + strlen(pattern);
194                 return 0;
195         }
196 }
197
198 static int grep_buffer(struct grep_opt *opt, const char *name,
199                        char *buf, unsigned long size)
200 {
201         char *bol = buf;
202         unsigned long left = size;
203         unsigned lno = 1;
204         struct pre_context_line {
205                 char *bol;
206                 char *eol;
207         } *prev = NULL, *pcl;
208         unsigned last_hit = 0;
209         unsigned last_shown = 0;
210         int binary_match_only = 0;
211         const char *hunk_mark = "";
212         unsigned count = 0;
213
214         if (buffer_is_binary(buf, size)) {
215                 switch (opt->binary) {
216                 case GREP_BINARY_DEFAULT:
217                         binary_match_only = 1;
218                         break;
219                 case GREP_BINARY_NOMATCH:
220                         return 0; /* Assume unmatch */
221                         break;
222                 default:
223                         break;
224                 }
225         }
226
227         if (opt->pre_context)
228                 prev = xcalloc(opt->pre_context, sizeof(*prev));
229         if (opt->pre_context || opt->post_context)
230                 hunk_mark = "--\n";
231
232         while (left) {
233                 regmatch_t pmatch[10];
234                 char *eol, ch;
235                 int hit = 0;
236                 struct grep_pat *p;
237
238                 eol = end_of_line(bol, &left);
239                 ch = *eol;
240                 *eol = 0;
241
242                 for (p = opt->pattern_list; p; p = p->next) {
243                         if (!opt->fixed) {
244                                 regex_t *exp = &p->regexp;
245                                 hit = !regexec(exp, bol, ARRAY_SIZE(pmatch),
246                                                pmatch, 0);
247                         }
248                         else {
249                                 hit = !fixmatch(p->pattern, bol, pmatch);
250                         }
251
252                         if (hit && opt->word_regexp) {
253                                 /* Match beginning must be either
254                                  * beginning of the line, or at word
255                                  * boundary (i.e. the last char must
256                                  * not be alnum or underscore).
257                                  */
258                                 if ((pmatch[0].rm_so < 0) ||
259                                     (eol - bol) <= pmatch[0].rm_so ||
260                                     (pmatch[0].rm_eo < 0) ||
261                                     (eol - bol) < pmatch[0].rm_eo)
262                                         die("regexp returned nonsense");
263                                 if (pmatch[0].rm_so != 0 &&
264                                     word_char(bol[pmatch[0].rm_so-1]))
265                                         hit = 0;
266                                 if (pmatch[0].rm_eo != (eol-bol) &&
267                                     word_char(bol[pmatch[0].rm_eo]))
268                                         hit = 0;
269                         }
270                         if (hit)
271                                 break;
272                 }
273                 /* "grep -v -e foo -e bla" should list lines
274                  * that do not have either, so inversion should
275                  * be done outside.
276                  */
277                 if (opt->invert)
278                         hit = !hit;
279                 if (opt->unmatch_name_only) {
280                         if (hit)
281                                 return 0;
282                         goto next_line;
283                 }
284                 if (hit) {
285                         count++;
286                         if (binary_match_only) {
287                                 printf("Binary file %s matches\n", name);
288                                 return 1;
289                         }
290                         if (opt->name_only) {
291                                 printf("%s\n", name);
292                                 return 1;
293                         }
294                         /* Hit at this line.  If we haven't shown the
295                          * pre-context lines, we would need to show them.
296                          * When asked to do "count", this still show
297                          * the context which is nonsense, but the user
298                          * deserves to get that ;-).
299                          */
300                         if (opt->pre_context) {
301                                 unsigned from;
302                                 if (opt->pre_context < lno)
303                                         from = lno - opt->pre_context;
304                                 else
305                                         from = 1;
306                                 if (from <= last_shown)
307                                         from = last_shown + 1;
308                                 if (last_shown && from != last_shown + 1)
309                                         printf(hunk_mark);
310                                 while (from < lno) {
311                                         pcl = &prev[lno-from-1];
312                                         show_line(opt, pcl->bol, pcl->eol,
313                                                   name, from, '-');
314                                         from++;
315                                 }
316                                 last_shown = lno-1;
317                         }
318                         if (last_shown && lno != last_shown + 1)
319                                 printf(hunk_mark);
320                         if (!opt->count)
321                                 show_line(opt, bol, eol, name, lno, ':');
322                         last_shown = last_hit = lno;
323                 }
324                 else if (last_hit &&
325                          lno <= last_hit + opt->post_context) {
326                         /* If the last hit is within the post context,
327                          * we need to show this line.
328                          */
329                         if (last_shown && lno != last_shown + 1)
330                                 printf(hunk_mark);
331                         show_line(opt, bol, eol, name, lno, '-');
332                         last_shown = lno;
333                 }
334                 if (opt->pre_context) {
335                         memmove(prev+1, prev,
336                                 (opt->pre_context-1) * sizeof(*prev));
337                         prev->bol = bol;
338                         prev->eol = eol;
339                 }
340
341         next_line:
342                 *eol = ch;
343                 bol = eol + 1;
344                 if (!left)
345                         break;
346                 left--;
347                 lno++;
348         }
349
350         if (opt->unmatch_name_only) {
351                 /* We did not see any hit, so we want to show this */
352                 printf("%s\n", name);
353                 return 1;
354         }
355
356         /* NEEDSWORK:
357          * The real "grep -c foo *.c" gives many "bar.c:0" lines,
358          * which feels mostly useless but sometimes useful.  Maybe
359          * make it another option?  For now suppress them.
360          */
361         if (opt->count && count)
362                 printf("%s:%u\n", name, count);
363         return !!last_hit;
364 }
365
366 static int grep_sha1(struct grep_opt *opt, const unsigned char *sha1, const char *name)
367 {
368         unsigned long size;
369         char *data;
370         char type[20];
371         int hit;
372         data = read_sha1_file(sha1, type, &size);
373         if (!data) {
374                 error("'%s': unable to read %s", name, sha1_to_hex(sha1));
375                 return 0;
376         }
377         hit = grep_buffer(opt, name, data, size);
378         free(data);
379         return hit;
380 }
381
382 static int grep_file(struct grep_opt *opt, const char *filename)
383 {
384         struct stat st;
385         int i;
386         char *data;
387         if (lstat(filename, &st) < 0) {
388         err_ret:
389                 if (errno != ENOENT)
390                         error("'%s': %s", filename, strerror(errno));
391                 return 0;
392         }
393         if (!st.st_size)
394                 return 0; /* empty file -- no grep hit */
395         if (!S_ISREG(st.st_mode))
396                 return 0;
397         i = open(filename, O_RDONLY);
398         if (i < 0)
399                 goto err_ret;
400         data = xmalloc(st.st_size + 1);
401         if (st.st_size != xread(i, data, st.st_size)) {
402                 error("'%s': short read %s", filename, strerror(errno));
403                 close(i);
404                 free(data);
405                 return 0;
406         }
407         close(i);
408         i = grep_buffer(opt, filename, data, st.st_size);
409         free(data);
410         return i;
411 }
412
413 static int exec_grep(int argc, const char **argv)
414 {
415         pid_t pid;
416         int status;
417
418         argv[argc] = NULL;
419         pid = fork();
420         if (pid < 0)
421                 return pid;
422         if (!pid) {
423                 execvp("grep", (char **) argv);
424                 exit(255);
425         }
426         while (waitpid(pid, &status, 0) < 0) {
427                 if (errno == EINTR)
428                         continue;
429                 return -1;
430         }
431         if (WIFEXITED(status)) {
432                 if (!WEXITSTATUS(status))
433                         return 1;
434                 return 0;
435         }
436         return -1;
437 }
438
439 #define MAXARGS 1000
440 #define ARGBUF 4096
441 #define push_arg(a) do { \
442         if (nr < MAXARGS) argv[nr++] = (a); \
443         else die("maximum number of args exceeded"); \
444         } while (0)
445
446 static int external_grep(struct grep_opt *opt, const char **paths, int cached)
447 {
448         int i, nr, argc, hit, len;
449         const char *argv[MAXARGS+1];
450         char randarg[ARGBUF];
451         char *argptr = randarg;
452         struct grep_pat *p;
453
454         len = nr = 0;
455         push_arg("grep");
456         if (opt->fixed)
457                 push_arg("-F");
458         if (opt->linenum)
459                 push_arg("-n");
460         if (opt->regflags & REG_EXTENDED)
461                 push_arg("-E");
462         if (opt->word_regexp)
463                 push_arg("-w");
464         if (opt->name_only)
465                 push_arg("-l");
466         if (opt->unmatch_name_only)
467                 push_arg("-L");
468         if (opt->count)
469                 push_arg("-c");
470         if (opt->post_context || opt->pre_context) {
471                 if (opt->post_context != opt->pre_context) {
472                         if (opt->pre_context) {
473                                 push_arg("-B");
474                                 len += snprintf(argptr, sizeof(randarg)-len,
475                                                 "%u", opt->pre_context);
476                                 if (sizeof(randarg) <= len)
477                                         die("maximum length of args exceeded");
478                                 push_arg(argptr);
479                                 argptr += len;
480                         }
481                         if (opt->post_context) {
482                                 push_arg("-A");
483                                 len += snprintf(argptr, sizeof(randarg)-len,
484                                                 "%u", opt->post_context);
485                                 if (sizeof(randarg) <= len)
486                                         die("maximum length of args exceeded");
487                                 push_arg(argptr);
488                                 argptr += len;
489                         }
490                 }
491                 else {
492                         push_arg("-C");
493                         len += snprintf(argptr, sizeof(randarg)-len,
494                                         "%u", opt->post_context);
495                         if (sizeof(randarg) <= len)
496                                 die("maximum length of args exceeded");
497                         push_arg(argptr);
498                         argptr += len;
499                 }
500         }
501         for (p = opt->pattern_list; p; p = p->next) {
502                 push_arg("-e");
503                 push_arg(p->pattern);
504         }
505
506         /*
507          * To make sure we get the header printed out when we want it,
508          * add /dev/null to the paths to grep.  This is unnecessary
509          * (and wrong) with "-l" or "-L", which always print out the
510          * name anyway.
511          *
512          * GNU grep has "-H", but this is portable.
513          */
514         if (!opt->name_only && !opt->unmatch_name_only)
515                 push_arg("/dev/null");
516
517         hit = 0;
518         argc = nr;
519         for (i = 0; i < active_nr; i++) {
520                 struct cache_entry *ce = active_cache[i];
521                 char *name;
522                 if (ce_stage(ce) || !S_ISREG(ntohl(ce->ce_mode)))
523                         continue;
524                 if (!pathspec_matches(paths, ce->name))
525                         continue;
526                 name = ce->name;
527                 if (name[0] == '-') {
528                         int len = ce_namelen(ce);
529                         name = xmalloc(len + 3);
530                         memcpy(name, "./", 2);
531                         memcpy(name + 2, ce->name, len + 1);
532                 }
533                 argv[argc++] = name;
534                 if (argc < MAXARGS)
535                         continue;
536                 hit += exec_grep(argc, argv);
537                 argc = nr;
538         }
539         if (argc > nr)
540                 hit += exec_grep(argc, argv);
541         return 0;
542 }
543
544 static int grep_cache(struct grep_opt *opt, const char **paths, int cached)
545 {
546         int hit = 0;
547         int nr;
548         read_cache();
549
550 #ifdef __unix__
551         /*
552          * Use the external "grep" command for the case where
553          * we grep through the checked-out files. It tends to
554          * be a lot more optimized
555          */
556         if (!cached) {
557                 hit = external_grep(opt, paths, cached);
558                 if (hit >= 0)
559                         return hit;
560         }
561 #endif
562
563         for (nr = 0; nr < active_nr; nr++) {
564                 struct cache_entry *ce = active_cache[nr];
565                 if (ce_stage(ce) || !S_ISREG(ntohl(ce->ce_mode)))
566                         continue;
567                 if (!pathspec_matches(paths, ce->name))
568                         continue;
569                 if (cached)
570                         hit |= grep_sha1(opt, ce->sha1, ce->name);
571                 else
572                         hit |= grep_file(opt, ce->name);
573         }
574         return hit;
575 }
576
577 static int grep_tree(struct grep_opt *opt, const char **paths,
578                      struct tree_desc *tree,
579                      const char *tree_name, const char *base)
580 {
581         unsigned mode;
582         int len;
583         int hit = 0;
584         const char *path;
585         const unsigned char *sha1;
586         char *down;
587         char *path_buf = xmalloc(PATH_MAX + strlen(tree_name) + 100);
588
589         if (tree_name[0]) {
590                 int offset = sprintf(path_buf, "%s:", tree_name);
591                 down = path_buf + offset;
592                 strcat(down, base);
593         }
594         else {
595                 down = path_buf;
596                 strcpy(down, base);
597         }
598         len = strlen(path_buf);
599
600         while (tree->size) {
601                 int pathlen;
602                 sha1 = tree_entry_extract(tree, &path, &mode);
603                 pathlen = strlen(path);
604                 strcpy(path_buf + len, path);
605
606                 if (S_ISDIR(mode))
607                         /* Match "abc/" against pathspec to
608                          * decide if we want to descend into "abc"
609                          * directory.
610                          */
611                         strcpy(path_buf + len + pathlen, "/");
612
613                 if (!pathspec_matches(paths, down))
614                         ;
615                 else if (S_ISREG(mode))
616                         hit |= grep_sha1(opt, sha1, path_buf);
617                 else if (S_ISDIR(mode)) {
618                         char type[20];
619                         struct tree_desc sub;
620                         void *data;
621                         data = read_sha1_file(sha1, type, &sub.size);
622                         if (!data)
623                                 die("unable to read tree (%s)",
624                                     sha1_to_hex(sha1));
625                         sub.buf = data;
626                         hit |= grep_tree(opt, paths, &sub, tree_name, down);
627                         free(data);
628                 }
629                 update_tree_entry(tree);
630         }
631         return hit;
632 }
633
634 static int grep_object(struct grep_opt *opt, const char **paths,
635                        struct object *obj, const char *name)
636 {
637         if (!strcmp(obj->type, blob_type))
638                 return grep_sha1(opt, obj->sha1, name);
639         if (!strcmp(obj->type, commit_type) ||
640             !strcmp(obj->type, tree_type)) {
641                 struct tree_desc tree;
642                 void *data;
643                 int hit;
644                 data = read_object_with_reference(obj->sha1, tree_type,
645                                                   &tree.size, NULL);
646                 if (!data)
647                         die("unable to read tree (%s)", sha1_to_hex(obj->sha1));
648                 tree.buf = data;
649                 hit = grep_tree(opt, paths, &tree, name, "");
650                 free(data);
651                 return hit;
652         }
653         die("unable to grep from object of type %s", obj->type);
654 }
655
656 static const char builtin_grep_usage[] =
657 "git-grep <option>* <rev>* [-e] <pattern> [<path>...]";
658
659 int cmd_grep(int argc, const char **argv, char **envp)
660 {
661         int hit = 0;
662         int cached = 0;
663         int seen_dashdash = 0;
664         struct grep_opt opt;
665         struct object_list *list, **tail, *object_list = NULL;
666         const char *prefix = setup_git_directory();
667         const char **paths = NULL;
668         int i;
669
670         memset(&opt, 0, sizeof(opt));
671         opt.pattern_tail = &opt.pattern_list;
672         opt.regflags = REG_NEWLINE;
673
674         /*
675          * If there is no -- then the paths must exist in the working
676          * tree.  If there is no explicit pattern specified with -e or
677          * -f, we take the first unrecognized non option to be the
678          * pattern, but then what follows it must be zero or more
679          * valid refs up to the -- (if exists), and then existing
680          * paths.  If there is an explicit pattern, then the first
681          * unrecocnized non option is the beginning of the refs list
682          * that continues up to the -- (if exists), and then paths.
683          */
684
685         tail = &object_list;
686         while (1 < argc) {
687                 const char *arg = argv[1];
688                 argc--; argv++;
689                 if (!strcmp("--cached", arg)) {
690                         cached = 1;
691                         continue;
692                 }
693                 if (!strcmp("-a", arg) ||
694                     !strcmp("--text", arg)) {
695                         opt.binary = GREP_BINARY_TEXT;
696                         continue;
697                 }
698                 if (!strcmp("-i", arg) ||
699                     !strcmp("--ignore-case", arg)) {
700                         opt.regflags |= REG_ICASE;
701                         continue;
702                 }
703                 if (!strcmp("-I", arg)) {
704                         opt.binary = GREP_BINARY_NOMATCH;
705                         continue;
706                 }
707                 if (!strcmp("-v", arg) ||
708                     !strcmp("--invert-match", arg)) {
709                         opt.invert = 1;
710                         continue;
711                 }
712                 if (!strcmp("-E", arg) ||
713                     !strcmp("--extended-regexp", arg)) {
714                         opt.regflags |= REG_EXTENDED;
715                         continue;
716                 }
717                 if (!strcmp("-F", arg) ||
718                     !strcmp("--fixed-strings", arg)) {
719                         opt.fixed = 1;
720                         continue;
721                 }
722                 if (!strcmp("-G", arg) ||
723                     !strcmp("--basic-regexp", arg)) {
724                         opt.regflags &= ~REG_EXTENDED;
725                         continue;
726                 }
727                 if (!strcmp("-n", arg)) {
728                         opt.linenum = 1;
729                         continue;
730                 }
731                 if (!strcmp("-H", arg)) {
732                         /* We always show the pathname, so this
733                          * is a noop.
734                          */
735                         continue;
736                 }
737                 if (!strcmp("-l", arg) ||
738                     !strcmp("--files-with-matches", arg)) {
739                         opt.name_only = 1;
740                         continue;
741                 }
742                 if (!strcmp("-L", arg) ||
743                     !strcmp("--files-without-match", arg)) {
744                         opt.unmatch_name_only = 1;
745                         continue;
746                 }
747                 if (!strcmp("-c", arg) ||
748                     !strcmp("--count", arg)) {
749                         opt.count = 1;
750                         continue;
751                 }
752                 if (!strcmp("-w", arg) ||
753                     !strcmp("--word-regexp", arg)) {
754                         opt.word_regexp = 1;
755                         continue;
756                 }
757                 if (!strncmp("-A", arg, 2) ||
758                     !strncmp("-B", arg, 2) ||
759                     !strncmp("-C", arg, 2) ||
760                     (arg[0] == '-' && '1' <= arg[1] && arg[1] <= '9')) {
761                         unsigned num;
762                         const char *scan;
763                         switch (arg[1]) {
764                         case 'A': case 'B': case 'C':
765                                 if (!arg[2]) {
766                                         if (argc <= 1)
767                                                 usage(builtin_grep_usage);
768                                         scan = *++argv;
769                                         argc--;
770                                 }
771                                 else
772                                         scan = arg + 2;
773                                 break;
774                         default:
775                                 scan = arg + 1;
776                                 break;
777                         }
778                         if (sscanf(scan, "%u", &num) != 1)
779                                 usage(builtin_grep_usage);
780                         switch (arg[1]) {
781                         case 'A':
782                                 opt.post_context = num;
783                                 break;
784                         default:
785                         case 'C':
786                                 opt.post_context = num;
787                         case 'B':
788                                 opt.pre_context = num;
789                                 break;
790                         }
791                         continue;
792                 }
793                 if (!strcmp("-f", arg)) {
794                         FILE *patterns;
795                         int lno = 0;
796                         char buf[1024];
797                         if (argc <= 1)
798                                 usage(builtin_grep_usage);
799                         patterns = fopen(argv[1], "r");
800                         if (!patterns)
801                                 die("'%s': %s", argv[1], strerror(errno));
802                         while (fgets(buf, sizeof(buf), patterns)) {
803                                 int len = strlen(buf);
804                                 if (buf[len-1] == '\n')
805                                         buf[len-1] = 0;
806                                 /* ignore empty line like grep does */
807                                 if (!buf[0])
808                                         continue;
809                                 add_pattern(&opt, strdup(buf), argv[1], ++lno);
810                         }
811                         fclose(patterns);
812                         argv++;
813                         argc--;
814                         continue;
815                 }
816                 if (!strcmp("-e", arg)) {
817                         if (1 < argc) {
818                                 add_pattern(&opt, argv[1], "-e option", 0);
819                                 argv++;
820                                 argc--;
821                                 continue;
822                         }
823                         usage(builtin_grep_usage);
824                 }
825                 if (!strcmp("--", arg))
826                         break;
827                 if (*arg == '-')
828                         usage(builtin_grep_usage);
829
830                 /* First unrecognized non-option token */
831                 if (!opt.pattern_list) {
832                         add_pattern(&opt, arg, "command line", 0);
833                         break;
834                 }
835                 else {
836                         /* We are looking at the first path or rev;
837                          * it is found at argv[1] after leaving the
838                          * loop.
839                          */
840                         argc++; argv--;
841                         break;
842                 }
843         }
844
845         if (!opt.pattern_list)
846                 die("no pattern given.");
847         if ((opt.regflags != REG_NEWLINE) && opt.fixed)
848                 die("cannot mix --fixed-strings and regexp");
849         if (!opt.fixed)
850                 compile_patterns(&opt);
851
852         /* Check revs and then paths */
853         for (i = 1; i < argc; i++) {
854                 const char *arg = argv[i];
855                 unsigned char sha1[20];
856                 /* Is it a rev? */
857                 if (!get_sha1(arg, sha1)) {
858                         struct object *object = parse_object(sha1);
859                         struct object_list *elem;
860                         if (!object)
861                                 die("bad object %s", arg);
862                         elem = object_list_insert(object, tail);
863                         elem->name = arg;
864                         tail = &elem->next;
865                         continue;
866                 }
867                 if (!strcmp(arg, "--")) {
868                         i++;
869                         seen_dashdash = 1;
870                 }
871                 break;
872         }
873
874         /* The rest are paths */
875         if (!seen_dashdash) {
876                 int j;
877                 for (j = i; j < argc; j++)
878                         verify_filename(prefix, argv[j]);
879         }
880
881         if (i < argc)
882                 paths = get_pathspec(prefix, argv + i);
883         else if (prefix) {
884                 paths = xcalloc(2, sizeof(const char *));
885                 paths[0] = prefix;
886                 paths[1] = NULL;
887         }
888
889         if (!object_list)
890                 return !grep_cache(&opt, paths, cached);
891
892         if (cached)
893                 die("both --cached and trees are given.");
894
895         for (list = object_list; list; list = list->next) {
896                 struct object *real_obj;
897                 real_obj = deref_tag(list->item, NULL, 0);
898                 if (grep_object(&opt, paths, real_obj, list->name))
899                         hit = 1;
900         }
901         return !hit;
902 }