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