Merge branch 'jc/maint-1.6.0-read-tree-overlay' into maint
[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 "grep.h"
14
15 #ifndef NO_EXTERNAL_GREP
16 #ifdef __unix__
17 #define NO_EXTERNAL_GREP 0
18 #else
19 #define NO_EXTERNAL_GREP 1
20 #endif
21 #endif
22
23 static int builtin_grep;
24
25 /*
26  * git grep pathspecs are somewhat different from diff-tree pathspecs;
27  * pathname wildcards are allowed.
28  */
29 static int pathspec_matches(const char **paths, const char *name)
30 {
31         int namelen, i;
32         if (!paths || !*paths)
33                 return 1;
34         namelen = strlen(name);
35         for (i = 0; paths[i]; i++) {
36                 const char *match = paths[i];
37                 int matchlen = strlen(match);
38                 const char *cp, *meta;
39
40                 if (!matchlen ||
41                     ((matchlen <= namelen) &&
42                      !strncmp(name, match, matchlen) &&
43                      (match[matchlen-1] == '/' ||
44                       name[matchlen] == '\0' || name[matchlen] == '/')))
45                         return 1;
46                 if (!fnmatch(match, name, 0))
47                         return 1;
48                 if (name[namelen-1] != '/')
49                         continue;
50
51                 /* We are being asked if the directory ("name") is worth
52                  * descending into.
53                  *
54                  * Find the longest leading directory name that does
55                  * not have metacharacter in the pathspec; the name
56                  * we are looking at must overlap with that directory.
57                  */
58                 for (cp = match, meta = NULL; cp - match < matchlen; cp++) {
59                         char ch = *cp;
60                         if (ch == '*' || ch == '[' || ch == '?') {
61                                 meta = cp;
62                                 break;
63                         }
64                 }
65                 if (!meta)
66                         meta = cp; /* fully literal */
67
68                 if (namelen <= meta - match) {
69                         /* Looking at "Documentation/" and
70                          * the pattern says "Documentation/howto/", or
71                          * "Documentation/diff*.txt".  The name we
72                          * have should match prefix.
73                          */
74                         if (!memcmp(match, name, namelen))
75                                 return 1;
76                         continue;
77                 }
78
79                 if (meta - match < namelen) {
80                         /* Looking at "Documentation/howto/" and
81                          * the pattern says "Documentation/h*";
82                          * match up to "Do.../h"; this avoids descending
83                          * into "Documentation/technical/".
84                          */
85                         if (!memcmp(match, name, meta - match))
86                                 return 1;
87                         continue;
88                 }
89         }
90         return 0;
91 }
92
93 static int grep_sha1(struct grep_opt *opt, const unsigned char *sha1, const char *name, int tree_name_len)
94 {
95         unsigned long size;
96         char *data;
97         enum object_type type;
98         char *to_free = NULL;
99         int hit;
100
101         data = read_sha1_file(sha1, &type, &size);
102         if (!data) {
103                 error("'%s': unable to read %s", name, sha1_to_hex(sha1));
104                 return 0;
105         }
106         if (opt->relative && opt->prefix_length) {
107                 static char name_buf[PATH_MAX];
108                 char *cp;
109                 int name_len = strlen(name) - opt->prefix_length + 1;
110
111                 if (!tree_name_len)
112                         name += opt->prefix_length;
113                 else {
114                         if (ARRAY_SIZE(name_buf) <= name_len)
115                                 cp = to_free = xmalloc(name_len);
116                         else
117                                 cp = name_buf;
118                         memcpy(cp, name, tree_name_len);
119                         strcpy(cp + tree_name_len,
120                                name + tree_name_len + opt->prefix_length);
121                         name = cp;
122                 }
123         }
124         hit = grep_buffer(opt, name, data, size);
125         free(data);
126         free(to_free);
127         return hit;
128 }
129
130 static int grep_file(struct grep_opt *opt, const char *filename)
131 {
132         struct stat st;
133         int i;
134         char *data;
135         size_t sz;
136
137         if (lstat(filename, &st) < 0) {
138         err_ret:
139                 if (errno != ENOENT)
140                         error("'%s': %s", filename, strerror(errno));
141                 return 0;
142         }
143         if (!st.st_size)
144                 return 0; /* empty file -- no grep hit */
145         if (!S_ISREG(st.st_mode))
146                 return 0;
147         sz = xsize_t(st.st_size);
148         i = open(filename, O_RDONLY);
149         if (i < 0)
150                 goto err_ret;
151         data = xmalloc(sz + 1);
152         if (st.st_size != read_in_full(i, data, sz)) {
153                 error("'%s': short read %s", filename, strerror(errno));
154                 close(i);
155                 free(data);
156                 return 0;
157         }
158         close(i);
159         if (opt->relative && opt->prefix_length)
160                 filename += opt->prefix_length;
161         i = grep_buffer(opt, filename, data, sz);
162         free(data);
163         return i;
164 }
165
166 #if !NO_EXTERNAL_GREP
167 static int exec_grep(int argc, const char **argv)
168 {
169         pid_t pid;
170         int status;
171
172         argv[argc] = NULL;
173         pid = fork();
174         if (pid < 0)
175                 return pid;
176         if (!pid) {
177                 execvp("grep", (char **) argv);
178                 exit(255);
179         }
180         while (waitpid(pid, &status, 0) < 0) {
181                 if (errno == EINTR)
182                         continue;
183                 return -1;
184         }
185         if (WIFEXITED(status)) {
186                 if (!WEXITSTATUS(status))
187                         return 1;
188                 return 0;
189         }
190         return -1;
191 }
192
193 #define MAXARGS 1000
194 #define ARGBUF 4096
195 #define push_arg(a) do { \
196         if (nr < MAXARGS) argv[nr++] = (a); \
197         else die("maximum number of args exceeded"); \
198         } while (0)
199
200 /*
201  * If you send a singleton filename to grep, it does not give
202  * the name of the file.  GNU grep has "-H" but we would want
203  * that behaviour in a portable way.
204  *
205  * So we keep two pathnames in argv buffer unsent to grep in
206  * the main loop if we need to do more than one grep.
207  */
208 static int flush_grep(struct grep_opt *opt,
209                       int argc, int arg0, const char **argv, int *kept)
210 {
211         int status;
212         int count = argc - arg0;
213         const char *kept_0 = NULL;
214
215         if (count <= 2) {
216                 /*
217                  * Because we keep at least 2 paths in the call from
218                  * the main loop (i.e. kept != NULL), and MAXARGS is
219                  * far greater than 2, this usually is a call to
220                  * conclude the grep.  However, the user could attempt
221                  * to overflow the argv buffer by giving too many
222                  * options to leave very small number of real
223                  * arguments even for the call in the main loop.
224                  */
225                 if (kept)
226                         die("insanely many options to grep");
227
228                 /*
229                  * If we have two or more paths, we do not have to do
230                  * anything special, but we need to push /dev/null to
231                  * get "-H" behaviour of GNU grep portably but when we
232                  * are not doing "-l" nor "-L" nor "-c".
233                  */
234                 if (count == 1 &&
235                     !opt->name_only &&
236                     !opt->unmatch_name_only &&
237                     !opt->count) {
238                         argv[argc++] = "/dev/null";
239                         argv[argc] = NULL;
240                 }
241         }
242
243         else if (kept) {
244                 /*
245                  * Called because we found many paths and haven't finished
246                  * iterating over the cache yet.  We keep two paths
247                  * for the concluding call.  argv[argc-2] and argv[argc-1]
248                  * has the last two paths, so save the first one away,
249                  * replace it with NULL while sending the list to grep,
250                  * and recover them after we are done.
251                  */
252                 *kept = 2;
253                 kept_0 = argv[argc-2];
254                 argv[argc-2] = NULL;
255                 argc -= 2;
256         }
257
258         status = exec_grep(argc, argv);
259
260         if (kept_0) {
261                 /*
262                  * Then recover them.  Now the last arg is beyond the
263                  * terminating NULL which is at argc, and the second
264                  * from the last is what we saved away in kept_0
265                  */
266                 argv[arg0++] = kept_0;
267                 argv[arg0] = argv[argc+1];
268         }
269         return status;
270 }
271
272 static int external_grep(struct grep_opt *opt, const char **paths, int cached)
273 {
274         int i, nr, argc, hit, len, status;
275         const char *argv[MAXARGS+1];
276         char randarg[ARGBUF];
277         char *argptr = randarg;
278         struct grep_pat *p;
279
280         if (opt->extended || (opt->relative && opt->prefix_length))
281                 return -1;
282         len = nr = 0;
283         push_arg("grep");
284         if (opt->fixed)
285                 push_arg("-F");
286         if (opt->linenum)
287                 push_arg("-n");
288         if (!opt->pathname)
289                 push_arg("-h");
290         if (opt->regflags & REG_EXTENDED)
291                 push_arg("-E");
292         if (opt->regflags & REG_ICASE)
293                 push_arg("-i");
294         if (opt->binary == GREP_BINARY_NOMATCH)
295                 push_arg("-I");
296         if (opt->word_regexp)
297                 push_arg("-w");
298         if (opt->name_only)
299                 push_arg("-l");
300         if (opt->unmatch_name_only)
301                 push_arg("-L");
302         if (opt->null_following_name)
303                 /* in GNU grep git's "-z" translates to "-Z" */
304                 push_arg("-Z");
305         if (opt->count)
306                 push_arg("-c");
307         if (opt->post_context || opt->pre_context) {
308                 if (opt->post_context != opt->pre_context) {
309                         if (opt->pre_context) {
310                                 push_arg("-B");
311                                 len += snprintf(argptr, sizeof(randarg)-len,
312                                                 "%u", opt->pre_context) + 1;
313                                 if (sizeof(randarg) <= len)
314                                         die("maximum length of args exceeded");
315                                 push_arg(argptr);
316                                 argptr += len;
317                         }
318                         if (opt->post_context) {
319                                 push_arg("-A");
320                                 len += snprintf(argptr, sizeof(randarg)-len,
321                                                 "%u", opt->post_context) + 1;
322                                 if (sizeof(randarg) <= len)
323                                         die("maximum length of args exceeded");
324                                 push_arg(argptr);
325                                 argptr += len;
326                         }
327                 }
328                 else {
329                         push_arg("-C");
330                         len += snprintf(argptr, sizeof(randarg)-len,
331                                         "%u", opt->post_context) + 1;
332                         if (sizeof(randarg) <= len)
333                                 die("maximum length of args exceeded");
334                         push_arg(argptr);
335                         argptr += len;
336                 }
337         }
338         for (p = opt->pattern_list; p; p = p->next) {
339                 push_arg("-e");
340                 push_arg(p->pattern);
341         }
342
343         hit = 0;
344         argc = nr;
345         for (i = 0; i < active_nr; i++) {
346                 struct cache_entry *ce = active_cache[i];
347                 char *name;
348                 int kept;
349                 if (!S_ISREG(ce->ce_mode))
350                         continue;
351                 if (!pathspec_matches(paths, ce->name))
352                         continue;
353                 name = ce->name;
354                 if (name[0] == '-') {
355                         int len = ce_namelen(ce);
356                         name = xmalloc(len + 3);
357                         memcpy(name, "./", 2);
358                         memcpy(name + 2, ce->name, len + 1);
359                 }
360                 argv[argc++] = name;
361                 if (MAXARGS <= argc) {
362                         status = flush_grep(opt, argc, nr, argv, &kept);
363                         if (0 < status)
364                                 hit = 1;
365                         argc = nr + kept;
366                 }
367                 if (ce_stage(ce)) {
368                         do {
369                                 i++;
370                         } while (i < active_nr &&
371                                  !strcmp(ce->name, active_cache[i]->name));
372                         i--; /* compensate for loop control */
373                 }
374         }
375         if (argc > nr) {
376                 status = flush_grep(opt, argc, nr, argv, NULL);
377                 if (0 < status)
378                         hit = 1;
379         }
380         return hit;
381 }
382 #endif
383
384 static int grep_cache(struct grep_opt *opt, const char **paths, int cached)
385 {
386         int hit = 0;
387         int nr;
388         read_cache();
389
390 #if !NO_EXTERNAL_GREP
391         /*
392          * Use the external "grep" command for the case where
393          * we grep through the checked-out files. It tends to
394          * be a lot more optimized
395          */
396         if (!cached && !builtin_grep) {
397                 hit = external_grep(opt, paths, cached);
398                 if (hit >= 0)
399                         return hit;
400         }
401 #endif
402
403         for (nr = 0; nr < active_nr; nr++) {
404                 struct cache_entry *ce = active_cache[nr];
405                 if (!S_ISREG(ce->ce_mode))
406                         continue;
407                 if (!pathspec_matches(paths, ce->name))
408                         continue;
409                 /*
410                  * If CE_VALID is on, we assume worktree file and its cache entry
411                  * are identical, even if worktree file has been modified, so use
412                  * cache version instead
413                  */
414                 if (cached || (ce->ce_flags & CE_VALID)) {
415                         if (ce_stage(ce))
416                                 continue;
417                         hit |= grep_sha1(opt, ce->sha1, ce->name, 0);
418                 }
419                 else
420                         hit |= grep_file(opt, ce->name);
421                 if (ce_stage(ce)) {
422                         do {
423                                 nr++;
424                         } while (nr < active_nr &&
425                                  !strcmp(ce->name, active_cache[nr]->name));
426                         nr--; /* compensate for loop control */
427                 }
428         }
429         free_grep_patterns(opt);
430         return hit;
431 }
432
433 static int grep_tree(struct grep_opt *opt, const char **paths,
434                      struct tree_desc *tree,
435                      const char *tree_name, const char *base)
436 {
437         int len;
438         int hit = 0;
439         struct name_entry entry;
440         char *down;
441         int tn_len = strlen(tree_name);
442         struct strbuf pathbuf;
443
444         strbuf_init(&pathbuf, PATH_MAX + tn_len);
445
446         if (tn_len) {
447                 strbuf_add(&pathbuf, tree_name, tn_len);
448                 strbuf_addch(&pathbuf, ':');
449                 tn_len = pathbuf.len;
450         }
451         strbuf_addstr(&pathbuf, base);
452         len = pathbuf.len;
453
454         while (tree_entry(tree, &entry)) {
455                 int te_len = tree_entry_len(entry.path, entry.sha1);
456                 pathbuf.len = len;
457                 strbuf_add(&pathbuf, entry.path, te_len);
458
459                 if (S_ISDIR(entry.mode))
460                         /* Match "abc/" against pathspec to
461                          * decide if we want to descend into "abc"
462                          * directory.
463                          */
464                         strbuf_addch(&pathbuf, '/');
465
466                 down = pathbuf.buf + tn_len;
467                 if (!pathspec_matches(paths, down))
468                         ;
469                 else if (S_ISREG(entry.mode))
470                         hit |= grep_sha1(opt, entry.sha1, pathbuf.buf, tn_len);
471                 else if (S_ISDIR(entry.mode)) {
472                         enum object_type type;
473                         struct tree_desc sub;
474                         void *data;
475                         unsigned long size;
476
477                         data = read_sha1_file(entry.sha1, &type, &size);
478                         if (!data)
479                                 die("unable to read tree (%s)",
480                                     sha1_to_hex(entry.sha1));
481                         init_tree_desc(&sub, data, size);
482                         hit |= grep_tree(opt, paths, &sub, tree_name, down);
483                         free(data);
484                 }
485         }
486         strbuf_release(&pathbuf);
487         return hit;
488 }
489
490 static int grep_object(struct grep_opt *opt, const char **paths,
491                        struct object *obj, const char *name)
492 {
493         if (obj->type == OBJ_BLOB)
494                 return grep_sha1(opt, obj->sha1, name, 0);
495         if (obj->type == OBJ_COMMIT || obj->type == OBJ_TREE) {
496                 struct tree_desc tree;
497                 void *data;
498                 unsigned long size;
499                 int hit;
500                 data = read_object_with_reference(obj->sha1, tree_type,
501                                                   &size, NULL);
502                 if (!data)
503                         die("unable to read tree (%s)", sha1_to_hex(obj->sha1));
504                 init_tree_desc(&tree, data, size);
505                 hit = grep_tree(opt, paths, &tree, name, "");
506                 free(data);
507                 return hit;
508         }
509         die("unable to grep from object of type %s", typename(obj->type));
510 }
511
512 static const char builtin_grep_usage[] =
513 "git grep <option>* [-e] <pattern> <rev>* [[--] <path>...]";
514
515 static const char emsg_invalid_context_len[] =
516 "%s: invalid context length argument";
517 static const char emsg_missing_context_len[] =
518 "missing context length argument";
519 static const char emsg_missing_argument[] =
520 "option requires an argument -%s";
521
522 int cmd_grep(int argc, const char **argv, const char *prefix)
523 {
524         int hit = 0;
525         int cached = 0;
526         int seen_dashdash = 0;
527         struct grep_opt opt;
528         struct object_array list = { 0, 0, NULL };
529         const char **paths = NULL;
530         int i;
531
532         memset(&opt, 0, sizeof(opt));
533         opt.prefix_length = (prefix && *prefix) ? strlen(prefix) : 0;
534         opt.relative = 1;
535         opt.pathname = 1;
536         opt.pattern_tail = &opt.pattern_list;
537         opt.regflags = REG_NEWLINE;
538
539         /*
540          * If there is no -- then the paths must exist in the working
541          * tree.  If there is no explicit pattern specified with -e or
542          * -f, we take the first unrecognized non option to be the
543          * pattern, but then what follows it must be zero or more
544          * valid refs up to the -- (if exists), and then existing
545          * paths.  If there is an explicit pattern, then the first
546          * unrecognized non option is the beginning of the refs list
547          * that continues up to the -- (if exists), and then paths.
548          */
549
550         while (1 < argc) {
551                 const char *arg = argv[1];
552                 argc--; argv++;
553                 if (!strcmp("--cached", arg)) {
554                         cached = 1;
555                         continue;
556                 }
557                 if (!strcmp("--no-ext-grep", arg)) {
558                         builtin_grep = 1;
559                         continue;
560                 }
561                 if (!strcmp("-a", arg) ||
562                     !strcmp("--text", arg)) {
563                         opt.binary = GREP_BINARY_TEXT;
564                         continue;
565                 }
566                 if (!strcmp("-i", arg) ||
567                     !strcmp("--ignore-case", arg)) {
568                         opt.regflags |= REG_ICASE;
569                         continue;
570                 }
571                 if (!strcmp("-I", arg)) {
572                         opt.binary = GREP_BINARY_NOMATCH;
573                         continue;
574                 }
575                 if (!strcmp("-v", arg) ||
576                     !strcmp("--invert-match", arg)) {
577                         opt.invert = 1;
578                         continue;
579                 }
580                 if (!strcmp("-E", arg) ||
581                     !strcmp("--extended-regexp", arg)) {
582                         opt.regflags |= REG_EXTENDED;
583                         continue;
584                 }
585                 if (!strcmp("-F", arg) ||
586                     !strcmp("--fixed-strings", arg)) {
587                         opt.fixed = 1;
588                         continue;
589                 }
590                 if (!strcmp("-G", arg) ||
591                     !strcmp("--basic-regexp", arg)) {
592                         opt.regflags &= ~REG_EXTENDED;
593                         continue;
594                 }
595                 if (!strcmp("-n", arg)) {
596                         opt.linenum = 1;
597                         continue;
598                 }
599                 if (!strcmp("-h", arg)) {
600                         opt.pathname = 0;
601                         continue;
602                 }
603                 if (!strcmp("-H", arg)) {
604                         opt.pathname = 1;
605                         continue;
606                 }
607                 if (!strcmp("-l", arg) ||
608                     !strcmp("--name-only", arg) ||
609                     !strcmp("--files-with-matches", arg)) {
610                         opt.name_only = 1;
611                         continue;
612                 }
613                 if (!strcmp("-L", arg) ||
614                     !strcmp("--files-without-match", arg)) {
615                         opt.unmatch_name_only = 1;
616                         continue;
617                 }
618                 if (!strcmp("-z", arg) ||
619                     !strcmp("--null", arg)) {
620                         opt.null_following_name = 1;
621                         continue;
622                 }
623                 if (!strcmp("-c", arg) ||
624                     !strcmp("--count", arg)) {
625                         opt.count = 1;
626                         continue;
627                 }
628                 if (!strcmp("-w", arg) ||
629                     !strcmp("--word-regexp", arg)) {
630                         opt.word_regexp = 1;
631                         continue;
632                 }
633                 if (!prefixcmp(arg, "-A") ||
634                     !prefixcmp(arg, "-B") ||
635                     !prefixcmp(arg, "-C") ||
636                     (arg[0] == '-' && '1' <= arg[1] && arg[1] <= '9')) {
637                         unsigned num;
638                         const char *scan;
639                         switch (arg[1]) {
640                         case 'A': case 'B': case 'C':
641                                 if (!arg[2]) {
642                                         if (argc <= 1)
643                                                 die(emsg_missing_context_len);
644                                         scan = *++argv;
645                                         argc--;
646                                 }
647                                 else
648                                         scan = arg + 2;
649                                 break;
650                         default:
651                                 scan = arg + 1;
652                                 break;
653                         }
654                         if (strtoul_ui(scan, 10, &num))
655                                 die(emsg_invalid_context_len, scan);
656                         switch (arg[1]) {
657                         case 'A':
658                                 opt.post_context = num;
659                                 break;
660                         default:
661                         case 'C':
662                                 opt.post_context = num;
663                         case 'B':
664                                 opt.pre_context = num;
665                                 break;
666                         }
667                         continue;
668                 }
669                 if (!strcmp("-f", arg)) {
670                         FILE *patterns;
671                         int lno = 0;
672                         char buf[1024];
673                         if (argc <= 1)
674                                 die(emsg_missing_argument, arg);
675                         patterns = fopen(argv[1], "r");
676                         if (!patterns)
677                                 die("'%s': %s", argv[1], strerror(errno));
678                         while (fgets(buf, sizeof(buf), patterns)) {
679                                 int len = strlen(buf);
680                                 if (len && buf[len-1] == '\n')
681                                         buf[len-1] = 0;
682                                 /* ignore empty line like grep does */
683                                 if (!buf[0])
684                                         continue;
685                                 append_grep_pattern(&opt, xstrdup(buf),
686                                                     argv[1], ++lno,
687                                                     GREP_PATTERN);
688                         }
689                         fclose(patterns);
690                         argv++;
691                         argc--;
692                         continue;
693                 }
694                 if (!strcmp("--not", arg)) {
695                         append_grep_pattern(&opt, arg, "command line", 0,
696                                             GREP_NOT);
697                         continue;
698                 }
699                 if (!strcmp("--and", arg)) {
700                         append_grep_pattern(&opt, arg, "command line", 0,
701                                             GREP_AND);
702                         continue;
703                 }
704                 if (!strcmp("--or", arg))
705                         continue; /* no-op */
706                 if (!strcmp("(", arg)) {
707                         append_grep_pattern(&opt, arg, "command line", 0,
708                                             GREP_OPEN_PAREN);
709                         continue;
710                 }
711                 if (!strcmp(")", arg)) {
712                         append_grep_pattern(&opt, arg, "command line", 0,
713                                             GREP_CLOSE_PAREN);
714                         continue;
715                 }
716                 if (!strcmp("--all-match", arg)) {
717                         opt.all_match = 1;
718                         continue;
719                 }
720                 if (!strcmp("-e", arg)) {
721                         if (1 < argc) {
722                                 append_grep_pattern(&opt, argv[1],
723                                                     "-e option", 0,
724                                                     GREP_PATTERN);
725                                 argv++;
726                                 argc--;
727                                 continue;
728                         }
729                         die(emsg_missing_argument, arg);
730                 }
731                 if (!strcmp("--full-name", arg)) {
732                         opt.relative = 0;
733                         continue;
734                 }
735                 if (!strcmp("--", arg)) {
736                         /* later processing wants to have this at argv[1] */
737                         argv--;
738                         argc++;
739                         break;
740                 }
741                 if (*arg == '-')
742                         usage(builtin_grep_usage);
743
744                 /* First unrecognized non-option token */
745                 if (!opt.pattern_list) {
746                         append_grep_pattern(&opt, arg, "command line", 0,
747                                             GREP_PATTERN);
748                         break;
749                 }
750                 else {
751                         /* We are looking at the first path or rev;
752                          * it is found at argv[1] after leaving the
753                          * loop.
754                          */
755                         argc++; argv--;
756                         break;
757                 }
758         }
759
760         if (!opt.pattern_list)
761                 die("no pattern given.");
762         if ((opt.regflags != REG_NEWLINE) && opt.fixed)
763                 die("cannot mix --fixed-strings and regexp");
764         compile_grep_patterns(&opt);
765
766         /* Check revs and then paths */
767         for (i = 1; i < argc; i++) {
768                 const char *arg = argv[i];
769                 unsigned char sha1[20];
770                 /* Is it a rev? */
771                 if (!get_sha1(arg, sha1)) {
772                         struct object *object = parse_object(sha1);
773                         if (!object)
774                                 die("bad object %s", arg);
775                         add_object_array(object, arg, &list);
776                         continue;
777                 }
778                 if (!strcmp(arg, "--")) {
779                         i++;
780                         seen_dashdash = 1;
781                 }
782                 break;
783         }
784
785         /* The rest are paths */
786         if (!seen_dashdash) {
787                 int j;
788                 for (j = i; j < argc; j++)
789                         verify_filename(prefix, argv[j]);
790         }
791
792         if (i < argc) {
793                 paths = get_pathspec(prefix, argv + i);
794                 if (opt.prefix_length && opt.relative) {
795                         /* Make sure we do not get outside of paths */
796                         for (i = 0; paths[i]; i++)
797                                 if (strncmp(prefix, paths[i], opt.prefix_length))
798                                         die("git grep: cannot generate relative filenames containing '..'");
799                 }
800         }
801         else if (prefix) {
802                 paths = xcalloc(2, sizeof(const char *));
803                 paths[0] = prefix;
804                 paths[1] = NULL;
805         }
806
807         if (!list.nr) {
808                 if (!cached)
809                         setup_work_tree();
810                 return !grep_cache(&opt, paths, cached);
811         }
812
813         if (cached)
814                 die("both --cached and trees are given.");
815
816         for (i = 0; i < list.nr; i++) {
817                 struct object *real_obj;
818                 real_obj = deref_tag(list.objects[i].item, NULL, 0);
819                 if (grep_object(&opt, paths, real_obj, list.objects[i].name))
820                         hit = 1;
821         }
822         free_grep_patterns(&opt);
823         return !hit;
824 }