shortlog: handle multi-line subjects like log --pretty=oneline et. al. do
[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->null_following_name)
299                 /* in GNU grep git's "-z" translates to "-Z" */
300                 push_arg("-Z");
301         if (opt->count)
302                 push_arg("-c");
303         if (opt->post_context || opt->pre_context) {
304                 if (opt->post_context != opt->pre_context) {
305                         if (opt->pre_context) {
306                                 push_arg("-B");
307                                 len += snprintf(argptr, sizeof(randarg)-len,
308                                                 "%u", opt->pre_context) + 1;
309                                 if (sizeof(randarg) <= len)
310                                         die("maximum length of args exceeded");
311                                 push_arg(argptr);
312                                 argptr += len;
313                         }
314                         if (opt->post_context) {
315                                 push_arg("-A");
316                                 len += snprintf(argptr, sizeof(randarg)-len,
317                                                 "%u", opt->post_context) + 1;
318                                 if (sizeof(randarg) <= len)
319                                         die("maximum length of args exceeded");
320                                 push_arg(argptr);
321                                 argptr += len;
322                         }
323                 }
324                 else {
325                         push_arg("-C");
326                         len += snprintf(argptr, sizeof(randarg)-len,
327                                         "%u", opt->post_context) + 1;
328                         if (sizeof(randarg) <= len)
329                                 die("maximum length of args exceeded");
330                         push_arg(argptr);
331                         argptr += len;
332                 }
333         }
334         for (p = opt->pattern_list; p; p = p->next) {
335                 push_arg("-e");
336                 push_arg(p->pattern);
337         }
338
339         hit = 0;
340         argc = nr;
341         for (i = 0; i < active_nr; i++) {
342                 struct cache_entry *ce = active_cache[i];
343                 char *name;
344                 int kept;
345                 if (!S_ISREG(ce->ce_mode))
346                         continue;
347                 if (!pathspec_matches(paths, ce->name))
348                         continue;
349                 name = ce->name;
350                 if (name[0] == '-') {
351                         int len = ce_namelen(ce);
352                         name = xmalloc(len + 3);
353                         memcpy(name, "./", 2);
354                         memcpy(name + 2, ce->name, len + 1);
355                 }
356                 argv[argc++] = name;
357                 if (MAXARGS <= argc) {
358                         status = flush_grep(opt, argc, nr, argv, &kept);
359                         if (0 < status)
360                                 hit = 1;
361                         argc = nr + kept;
362                 }
363                 if (ce_stage(ce)) {
364                         do {
365                                 i++;
366                         } while (i < active_nr &&
367                                  !strcmp(ce->name, active_cache[i]->name));
368                         i--; /* compensate for loop control */
369                 }
370         }
371         if (argc > nr) {
372                 status = flush_grep(opt, argc, nr, argv, NULL);
373                 if (0 < status)
374                         hit = 1;
375         }
376         return hit;
377 }
378 #endif
379
380 static int grep_cache(struct grep_opt *opt, const char **paths, int cached)
381 {
382         int hit = 0;
383         int nr;
384         read_cache();
385
386 #if !NO_EXTERNAL_GREP
387         /*
388          * Use the external "grep" command for the case where
389          * we grep through the checked-out files. It tends to
390          * be a lot more optimized
391          */
392         if (!cached) {
393                 hit = external_grep(opt, paths, cached);
394                 if (hit >= 0)
395                         return hit;
396         }
397 #endif
398
399         for (nr = 0; nr < active_nr; nr++) {
400                 struct cache_entry *ce = active_cache[nr];
401                 if (!S_ISREG(ce->ce_mode))
402                         continue;
403                 if (!pathspec_matches(paths, ce->name))
404                         continue;
405                 if (cached) {
406                         if (ce_stage(ce))
407                                 continue;
408                         hit |= grep_sha1(opt, ce->sha1, ce->name, 0);
409                 }
410                 else
411                         hit |= grep_file(opt, ce->name);
412                 if (ce_stage(ce)) {
413                         do {
414                                 nr++;
415                         } while (nr < active_nr &&
416                                  !strcmp(ce->name, active_cache[nr]->name));
417                         nr--; /* compensate for loop control */
418                 }
419         }
420         free_grep_patterns(opt);
421         return hit;
422 }
423
424 static int grep_tree(struct grep_opt *opt, const char **paths,
425                      struct tree_desc *tree,
426                      const char *tree_name, const char *base)
427 {
428         int len;
429         int hit = 0;
430         struct name_entry entry;
431         char *down;
432         int tn_len = strlen(tree_name);
433         struct strbuf pathbuf;
434
435         strbuf_init(&pathbuf, PATH_MAX + tn_len);
436
437         if (tn_len) {
438                 strbuf_add(&pathbuf, tree_name, tn_len);
439                 strbuf_addch(&pathbuf, ':');
440                 tn_len = pathbuf.len;
441         }
442         strbuf_addstr(&pathbuf, base);
443         len = pathbuf.len;
444
445         while (tree_entry(tree, &entry)) {
446                 int te_len = tree_entry_len(entry.path, entry.sha1);
447                 pathbuf.len = len;
448                 strbuf_add(&pathbuf, entry.path, te_len);
449
450                 if (S_ISDIR(entry.mode))
451                         /* Match "abc/" against pathspec to
452                          * decide if we want to descend into "abc"
453                          * directory.
454                          */
455                         strbuf_addch(&pathbuf, '/');
456
457                 down = pathbuf.buf + tn_len;
458                 if (!pathspec_matches(paths, down))
459                         ;
460                 else if (S_ISREG(entry.mode))
461                         hit |= grep_sha1(opt, entry.sha1, pathbuf.buf, tn_len);
462                 else if (S_ISDIR(entry.mode)) {
463                         enum object_type type;
464                         struct tree_desc sub;
465                         void *data;
466                         unsigned long size;
467
468                         data = read_sha1_file(entry.sha1, &type, &size);
469                         if (!data)
470                                 die("unable to read tree (%s)",
471                                     sha1_to_hex(entry.sha1));
472                         init_tree_desc(&sub, data, size);
473                         hit |= grep_tree(opt, paths, &sub, tree_name, down);
474                         free(data);
475                 }
476         }
477         strbuf_release(&pathbuf);
478         return hit;
479 }
480
481 static int grep_object(struct grep_opt *opt, const char **paths,
482                        struct object *obj, const char *name)
483 {
484         if (obj->type == OBJ_BLOB)
485                 return grep_sha1(opt, obj->sha1, name, 0);
486         if (obj->type == OBJ_COMMIT || obj->type == OBJ_TREE) {
487                 struct tree_desc tree;
488                 void *data;
489                 unsigned long size;
490                 int hit;
491                 data = read_object_with_reference(obj->sha1, tree_type,
492                                                   &size, NULL);
493                 if (!data)
494                         die("unable to read tree (%s)", sha1_to_hex(obj->sha1));
495                 init_tree_desc(&tree, data, size);
496                 hit = grep_tree(opt, paths, &tree, name, "");
497                 free(data);
498                 return hit;
499         }
500         die("unable to grep from object of type %s", typename(obj->type));
501 }
502
503 static const char builtin_grep_usage[] =
504 "git grep <option>* [-e] <pattern> <rev>* [[--] <path>...]";
505
506 static const char emsg_invalid_context_len[] =
507 "%s: invalid context length argument";
508 static const char emsg_missing_context_len[] =
509 "missing context length argument";
510 static const char emsg_missing_argument[] =
511 "option requires an argument -%s";
512
513 int cmd_grep(int argc, const char **argv, const char *prefix)
514 {
515         int hit = 0;
516         int cached = 0;
517         int seen_dashdash = 0;
518         struct grep_opt opt;
519         struct object_array list = { 0, 0, NULL };
520         const char **paths = NULL;
521         int i;
522
523         memset(&opt, 0, sizeof(opt));
524         opt.prefix_length = (prefix && *prefix) ? strlen(prefix) : 0;
525         opt.relative = 1;
526         opt.pathname = 1;
527         opt.pattern_tail = &opt.pattern_list;
528         opt.regflags = REG_NEWLINE;
529
530         /*
531          * If there is no -- then the paths must exist in the working
532          * tree.  If there is no explicit pattern specified with -e or
533          * -f, we take the first unrecognized non option to be the
534          * pattern, but then what follows it must be zero or more
535          * valid refs up to the -- (if exists), and then existing
536          * paths.  If there is an explicit pattern, then the first
537          * unrecognized non option is the beginning of the refs list
538          * that continues up to the -- (if exists), and then paths.
539          */
540
541         while (1 < argc) {
542                 const char *arg = argv[1];
543                 argc--; argv++;
544                 if (!strcmp("--cached", arg)) {
545                         cached = 1;
546                         continue;
547                 }
548                 if (!strcmp("-a", arg) ||
549                     !strcmp("--text", arg)) {
550                         opt.binary = GREP_BINARY_TEXT;
551                         continue;
552                 }
553                 if (!strcmp("-i", arg) ||
554                     !strcmp("--ignore-case", arg)) {
555                         opt.regflags |= REG_ICASE;
556                         continue;
557                 }
558                 if (!strcmp("-I", arg)) {
559                         opt.binary = GREP_BINARY_NOMATCH;
560                         continue;
561                 }
562                 if (!strcmp("-v", arg) ||
563                     !strcmp("--invert-match", arg)) {
564                         opt.invert = 1;
565                         continue;
566                 }
567                 if (!strcmp("-E", arg) ||
568                     !strcmp("--extended-regexp", arg)) {
569                         opt.regflags |= REG_EXTENDED;
570                         continue;
571                 }
572                 if (!strcmp("-F", arg) ||
573                     !strcmp("--fixed-strings", arg)) {
574                         opt.fixed = 1;
575                         continue;
576                 }
577                 if (!strcmp("-G", arg) ||
578                     !strcmp("--basic-regexp", arg)) {
579                         opt.regflags &= ~REG_EXTENDED;
580                         continue;
581                 }
582                 if (!strcmp("-n", arg)) {
583                         opt.linenum = 1;
584                         continue;
585                 }
586                 if (!strcmp("-h", arg)) {
587                         opt.pathname = 0;
588                         continue;
589                 }
590                 if (!strcmp("-H", arg)) {
591                         opt.pathname = 1;
592                         continue;
593                 }
594                 if (!strcmp("-l", arg) ||
595                     !strcmp("--name-only", arg) ||
596                     !strcmp("--files-with-matches", arg)) {
597                         opt.name_only = 1;
598                         continue;
599                 }
600                 if (!strcmp("-L", arg) ||
601                     !strcmp("--files-without-match", arg)) {
602                         opt.unmatch_name_only = 1;
603                         continue;
604                 }
605                 if (!strcmp("-z", arg) ||
606                     !strcmp("--null", arg)) {
607                         opt.null_following_name = 1;
608                         continue;
609                 }
610                 if (!strcmp("-c", arg) ||
611                     !strcmp("--count", arg)) {
612                         opt.count = 1;
613                         continue;
614                 }
615                 if (!strcmp("-w", arg) ||
616                     !strcmp("--word-regexp", arg)) {
617                         opt.word_regexp = 1;
618                         continue;
619                 }
620                 if (!prefixcmp(arg, "-A") ||
621                     !prefixcmp(arg, "-B") ||
622                     !prefixcmp(arg, "-C") ||
623                     (arg[0] == '-' && '1' <= arg[1] && arg[1] <= '9')) {
624                         unsigned num;
625                         const char *scan;
626                         switch (arg[1]) {
627                         case 'A': case 'B': case 'C':
628                                 if (!arg[2]) {
629                                         if (argc <= 1)
630                                                 die(emsg_missing_context_len);
631                                         scan = *++argv;
632                                         argc--;
633                                 }
634                                 else
635                                         scan = arg + 2;
636                                 break;
637                         default:
638                                 scan = arg + 1;
639                                 break;
640                         }
641                         if (strtoul_ui(scan, 10, &num))
642                                 die(emsg_invalid_context_len, scan);
643                         switch (arg[1]) {
644                         case 'A':
645                                 opt.post_context = num;
646                                 break;
647                         default:
648                         case 'C':
649                                 opt.post_context = num;
650                         case 'B':
651                                 opt.pre_context = num;
652                                 break;
653                         }
654                         continue;
655                 }
656                 if (!strcmp("-f", arg)) {
657                         FILE *patterns;
658                         int lno = 0;
659                         char buf[1024];
660                         if (argc <= 1)
661                                 die(emsg_missing_argument, arg);
662                         patterns = fopen(argv[1], "r");
663                         if (!patterns)
664                                 die("'%s': %s", argv[1], strerror(errno));
665                         while (fgets(buf, sizeof(buf), patterns)) {
666                                 int len = strlen(buf);
667                                 if (len && buf[len-1] == '\n')
668                                         buf[len-1] = 0;
669                                 /* ignore empty line like grep does */
670                                 if (!buf[0])
671                                         continue;
672                                 append_grep_pattern(&opt, xstrdup(buf),
673                                                     argv[1], ++lno,
674                                                     GREP_PATTERN);
675                         }
676                         fclose(patterns);
677                         argv++;
678                         argc--;
679                         continue;
680                 }
681                 if (!strcmp("--not", arg)) {
682                         append_grep_pattern(&opt, arg, "command line", 0,
683                                             GREP_NOT);
684                         continue;
685                 }
686                 if (!strcmp("--and", arg)) {
687                         append_grep_pattern(&opt, arg, "command line", 0,
688                                             GREP_AND);
689                         continue;
690                 }
691                 if (!strcmp("--or", arg))
692                         continue; /* no-op */
693                 if (!strcmp("(", arg)) {
694                         append_grep_pattern(&opt, arg, "command line", 0,
695                                             GREP_OPEN_PAREN);
696                         continue;
697                 }
698                 if (!strcmp(")", arg)) {
699                         append_grep_pattern(&opt, arg, "command line", 0,
700                                             GREP_CLOSE_PAREN);
701                         continue;
702                 }
703                 if (!strcmp("--all-match", arg)) {
704                         opt.all_match = 1;
705                         continue;
706                 }
707                 if (!strcmp("-e", arg)) {
708                         if (1 < argc) {
709                                 append_grep_pattern(&opt, argv[1],
710                                                     "-e option", 0,
711                                                     GREP_PATTERN);
712                                 argv++;
713                                 argc--;
714                                 continue;
715                         }
716                         die(emsg_missing_argument, arg);
717                 }
718                 if (!strcmp("--full-name", arg)) {
719                         opt.relative = 0;
720                         continue;
721                 }
722                 if (!strcmp("--", arg)) {
723                         /* later processing wants to have this at argv[1] */
724                         argv--;
725                         argc++;
726                         break;
727                 }
728                 if (*arg == '-')
729                         usage(builtin_grep_usage);
730
731                 /* First unrecognized non-option token */
732                 if (!opt.pattern_list) {
733                         append_grep_pattern(&opt, arg, "command line", 0,
734                                             GREP_PATTERN);
735                         break;
736                 }
737                 else {
738                         /* We are looking at the first path or rev;
739                          * it is found at argv[1] after leaving the
740                          * loop.
741                          */
742                         argc++; argv--;
743                         break;
744                 }
745         }
746
747         if (!opt.pattern_list)
748                 die("no pattern given.");
749         if ((opt.regflags != REG_NEWLINE) && opt.fixed)
750                 die("cannot mix --fixed-strings and regexp");
751         compile_grep_patterns(&opt);
752
753         /* Check revs and then paths */
754         for (i = 1; i < argc; i++) {
755                 const char *arg = argv[i];
756                 unsigned char sha1[20];
757                 /* Is it a rev? */
758                 if (!get_sha1(arg, sha1)) {
759                         struct object *object = parse_object(sha1);
760                         if (!object)
761                                 die("bad object %s", arg);
762                         add_object_array(object, arg, &list);
763                         continue;
764                 }
765                 if (!strcmp(arg, "--")) {
766                         i++;
767                         seen_dashdash = 1;
768                 }
769                 break;
770         }
771
772         /* The rest are paths */
773         if (!seen_dashdash) {
774                 int j;
775                 for (j = i; j < argc; j++)
776                         verify_filename(prefix, argv[j]);
777         }
778
779         if (i < argc) {
780                 paths = get_pathspec(prefix, argv + i);
781                 if (opt.prefix_length && opt.relative) {
782                         /* Make sure we do not get outside of paths */
783                         for (i = 0; paths[i]; i++)
784                                 if (strncmp(prefix, paths[i], opt.prefix_length))
785                                         die("git grep: cannot generate relative filenames containing '..'");
786                 }
787         }
788         else if (prefix) {
789                 paths = xcalloc(2, sizeof(const char *));
790                 paths[0] = prefix;
791                 paths[1] = NULL;
792         }
793
794         if (!list.nr) {
795                 if (!cached)
796                         setup_work_tree();
797                 return !grep_cache(&opt, paths, cached);
798         }
799
800         if (cached)
801                 die("both --cached and trees are given.");
802
803         for (i = 0; i < list.nr; i++) {
804                 struct object *real_obj;
805                 real_obj = deref_tag(list.objects[i].item, NULL, 0);
806                 if (grep_object(&opt, paths, real_obj, list.objects[i].name))
807                         hit = 1;
808         }
809         free_grep_patterns(&opt);
810         return !hit;
811 }