Merge branch 'jc/grep'
[git] / builtin-grep.c
1 /*
2  * Builtin "git grep"
3  *
4  * Copyright (c) 2006 Junio C Hamano
5  */
6 #include "cache.h"
7 #include "blob.h"
8 #include "tree.h"
9 #include "commit.h"
10 #include "tag.h"
11 #include "tree-walk.h"
12 #include "builtin.h"
13 #include <regex.h>
14 #include <fnmatch.h>
15 #include <sys/wait.h>
16
17 /*
18  * git grep pathspecs are somewhat different from diff-tree pathspecs;
19  * pathname wildcards are allowed.
20  */
21 static int pathspec_matches(const char **paths, const char *name)
22 {
23         int namelen, i;
24         if (!paths || !*paths)
25                 return 1;
26         namelen = strlen(name);
27         for (i = 0; paths[i]; i++) {
28                 const char *match = paths[i];
29                 int matchlen = strlen(match);
30                 const char *cp, *meta;
31
32                 if (!matchlen ||
33                     ((matchlen <= namelen) &&
34                      !strncmp(name, match, matchlen) &&
35                      (match[matchlen-1] == '/' ||
36                       name[matchlen] == '\0' || name[matchlen] == '/')))
37                         return 1;
38                 if (!fnmatch(match, name, 0))
39                         return 1;
40                 if (name[namelen-1] != '/')
41                         continue;
42
43                 /* We are being asked if the directory ("name") is worth
44                  * descending into.
45                  *
46                  * Find the longest leading directory name that does
47                  * not have metacharacter in the pathspec; the name
48                  * we are looking at must overlap with that directory.
49                  */
50                 for (cp = match, meta = NULL; cp - match < matchlen; cp++) {
51                         char ch = *cp;
52                         if (ch == '*' || ch == '[' || ch == '?') {
53                                 meta = cp;
54                                 break;
55                         }
56                 }
57                 if (!meta)
58                         meta = cp; /* fully literal */
59
60                 if (namelen <= meta - match) {
61                         /* Looking at "Documentation/" and
62                          * the pattern says "Documentation/howto/", or
63                          * "Documentation/diff*.txt".  The name we
64                          * have should match prefix.
65                          */
66                         if (!memcmp(match, name, namelen))
67                                 return 1;
68                         continue;
69                 }
70
71                 if (meta - match < namelen) {
72                         /* Looking at "Documentation/howto/" and
73                          * the pattern says "Documentation/h*";
74                          * match up to "Do.../h"; this avoids descending
75                          * into "Documentation/technical/".
76                          */
77                         if (!memcmp(match, name, meta - match))
78                                 return 1;
79                         continue;
80                 }
81         }
82         return 0;
83 }
84
85 enum grep_pat_token {
86         GREP_PATTERN,
87         GREP_AND,
88         GREP_OPEN_PAREN,
89         GREP_CLOSE_PAREN,
90         GREP_NOT,
91         GREP_OR,
92 };
93
94 struct grep_pat {
95         struct grep_pat *next;
96         const char *origin;
97         int no;
98         enum grep_pat_token token;
99         const char *pattern;
100         regex_t regexp;
101 };
102
103 enum grep_expr_node {
104         GREP_NODE_ATOM,
105         GREP_NODE_NOT,
106         GREP_NODE_AND,
107         GREP_NODE_OR,
108 };
109
110 struct grep_expr {
111         enum grep_expr_node node;
112         union {
113                 struct grep_pat *atom;
114                 struct grep_expr *unary;
115                 struct {
116                         struct grep_expr *left;
117                         struct grep_expr *right;
118                 } binary;
119         } u;
120 };
121
122 struct grep_opt {
123         struct grep_pat *pattern_list;
124         struct grep_pat **pattern_tail;
125         struct grep_expr *pattern_expression;
126         regex_t regexp;
127         unsigned linenum:1;
128         unsigned invert:1;
129         unsigned name_only:1;
130         unsigned unmatch_name_only:1;
131         unsigned count:1;
132         unsigned word_regexp:1;
133         unsigned fixed:1;
134 #define GREP_BINARY_DEFAULT     0
135 #define GREP_BINARY_NOMATCH     1
136 #define GREP_BINARY_TEXT        2
137         unsigned binary:2;
138         unsigned extended:1;
139         int regflags;
140         unsigned pre_context;
141         unsigned post_context;
142 };
143
144 static void add_pattern(struct grep_opt *opt, const char *pat,
145                         const char *origin, int no, enum grep_pat_token t)
146 {
147         struct grep_pat *p = xcalloc(1, sizeof(*p));
148         p->pattern = pat;
149         p->origin = origin;
150         p->no = no;
151         p->token = t;
152         *opt->pattern_tail = p;
153         opt->pattern_tail = &p->next;
154         p->next = NULL;
155 }
156
157 static void compile_regexp(struct grep_pat *p, struct grep_opt *opt)
158 {
159         int err = regcomp(&p->regexp, p->pattern, opt->regflags);
160         if (err) {
161                 char errbuf[1024];
162                 char where[1024];
163                 if (p->no)
164                         sprintf(where, "In '%s' at %d, ",
165                                 p->origin, p->no);
166                 else if (p->origin)
167                         sprintf(where, "%s, ", p->origin);
168                 else
169                         where[0] = 0;
170                 regerror(err, &p->regexp, errbuf, 1024);
171                 regfree(&p->regexp);
172                 die("%s'%s': %s", where, p->pattern, errbuf);
173         }
174 }
175
176 #if DEBUG
177 static inline void indent(int in)
178 {
179         int i;
180         for (i = 0; i < in; i++) putchar(' ');
181 }
182
183 static void dump_pattern_exp(struct grep_expr *x, int in)
184 {
185         switch (x->node) {
186         case GREP_NODE_ATOM:
187                 indent(in);
188                 puts(x->u.atom->pattern);
189                 break;
190         case GREP_NODE_NOT:
191                 indent(in);
192                 puts("--not");
193                 dump_pattern_exp(x->u.unary, in+1);
194                 break;
195         case GREP_NODE_AND:
196                 dump_pattern_exp(x->u.binary.left, in+1);
197                 indent(in);
198                 puts("--and");
199                 dump_pattern_exp(x->u.binary.right, in+1);
200                 break;
201         case GREP_NODE_OR:
202                 dump_pattern_exp(x->u.binary.left, in+1);
203                 indent(in);
204                 puts("--or");
205                 dump_pattern_exp(x->u.binary.right, in+1);
206                 break;
207         }
208 }
209
210 static void looking_at(const char *msg, struct grep_pat **list)
211 {
212         struct grep_pat *p = *list;
213         fprintf(stderr, "%s: looking at ", msg);
214         if (!p)
215                 fprintf(stderr, "empty\n");
216         else
217                 fprintf(stderr, "<%s>\n", p->pattern);
218 }
219 #else
220 #define looking_at(a,b) do {} while(0)
221 #endif
222
223 static struct grep_expr *compile_pattern_expr(struct grep_pat **);
224 static struct grep_expr *compile_pattern_atom(struct grep_pat **list)
225 {
226         struct grep_pat *p;
227         struct grep_expr *x;
228
229         looking_at("atom", list);
230
231         p = *list;
232         switch (p->token) {
233         case GREP_PATTERN: /* atom */
234                 x = xcalloc(1, sizeof (struct grep_expr));
235                 x->node = GREP_NODE_ATOM;
236                 x->u.atom = p;
237                 *list = p->next;
238                 return x;
239         case GREP_OPEN_PAREN:
240                 *list = p->next;
241                 x = compile_pattern_expr(list);
242                 if (!x)
243                         return NULL;
244                 if (!*list || (*list)->token != GREP_CLOSE_PAREN)
245                         die("unmatched parenthesis");
246                 *list = (*list)->next;
247                 return x;
248         default:
249                 return NULL;
250         }
251 }
252
253 static struct grep_expr *compile_pattern_not(struct grep_pat **list)
254 {
255         struct grep_pat *p;
256         struct grep_expr *x;
257
258         looking_at("not", list);
259
260         p = *list;
261         switch (p->token) {
262         case GREP_NOT:
263                 if (!p->next)
264                         die("--not not followed by pattern expression");
265                 *list = p->next;
266                 x = xcalloc(1, sizeof (struct grep_expr));
267                 x->node = GREP_NODE_NOT;
268                 x->u.unary = compile_pattern_not(list);
269                 if (!x->u.unary)
270                         die("--not followed by non pattern expression");
271                 return x;
272         default:
273                 return compile_pattern_atom(list);
274         }
275 }
276
277 static struct grep_expr *compile_pattern_and(struct grep_pat **list)
278 {
279         struct grep_pat *p;
280         struct grep_expr *x, *y, *z;
281
282         looking_at("and", list);
283
284         x = compile_pattern_not(list);
285         p = *list;
286         if (p && p->token == GREP_AND) {
287                 if (!p->next)
288                         die("--and not followed by pattern expression");
289                 *list = p->next;
290                 y = compile_pattern_and(list);
291                 if (!y)
292                         die("--and not followed by pattern expression");
293                 z = xcalloc(1, sizeof (struct grep_expr));
294                 z->node = GREP_NODE_AND;
295                 z->u.binary.left = x;
296                 z->u.binary.right = y;
297                 return z;
298         }
299         return x;
300 }
301
302 static struct grep_expr *compile_pattern_or(struct grep_pat **list)
303 {
304         struct grep_pat *p;
305         struct grep_expr *x, *y, *z;
306
307         looking_at("or", list);
308
309         x = compile_pattern_and(list);
310         p = *list;
311         if (x && p && p->token != GREP_CLOSE_PAREN) {
312                 y = compile_pattern_or(list);
313                 if (!y)
314                         die("not a pattern expression %s", p->pattern);
315                 z = xcalloc(1, sizeof (struct grep_expr));
316                 z->node = GREP_NODE_OR;
317                 z->u.binary.left = x;
318                 z->u.binary.right = y;
319                 return z;
320         }
321         return x;
322 }
323
324 static struct grep_expr *compile_pattern_expr(struct grep_pat **list)
325 {
326         looking_at("expr", list);
327
328         return compile_pattern_or(list);
329 }
330
331 static void compile_patterns(struct grep_opt *opt)
332 {
333         struct grep_pat *p;
334
335         /* First compile regexps */
336         for (p = opt->pattern_list; p; p = p->next) {
337                 if (p->token == GREP_PATTERN)
338                         compile_regexp(p, opt);
339                 else
340                         opt->extended = 1;
341         }
342
343         if (!opt->extended)
344                 return;
345
346         /* Then bundle them up in an expression.
347          * A classic recursive descent parser would do.
348          */
349         p = opt->pattern_list;
350         opt->pattern_expression = compile_pattern_expr(&p);
351 #if DEBUG
352         dump_pattern_exp(opt->pattern_expression, 0);
353 #endif
354         if (p)
355                 die("incomplete pattern expression: %s", p->pattern);
356 }
357
358 static char *end_of_line(char *cp, unsigned long *left)
359 {
360         unsigned long l = *left;
361         while (l && *cp != '\n') {
362                 l--;
363                 cp++;
364         }
365         *left = l;
366         return cp;
367 }
368
369 static int word_char(char ch)
370 {
371         return isalnum(ch) || ch == '_';
372 }
373
374 static void show_line(struct grep_opt *opt, const char *bol, const char *eol,
375                       const char *name, unsigned lno, char sign)
376 {
377         printf("%s%c", name, sign);
378         if (opt->linenum)
379                 printf("%d%c", lno, sign);
380         printf("%.*s\n", (int)(eol-bol), bol);
381 }
382
383 /*
384  * NEEDSWORK: share code with diff.c
385  */
386 #define FIRST_FEW_BYTES 8000
387 static int buffer_is_binary(const char *ptr, unsigned long size)
388 {
389         if (FIRST_FEW_BYTES < size)
390                 size = FIRST_FEW_BYTES;
391         if (memchr(ptr, 0, size))
392                 return 1;
393         return 0;
394 }
395
396 static int fixmatch(const char *pattern, char *line, regmatch_t *match)
397 {
398         char *hit = strstr(line, pattern);
399         if (!hit) {
400                 match->rm_so = match->rm_eo = -1;
401                 return REG_NOMATCH;
402         }
403         else {
404                 match->rm_so = hit - line;
405                 match->rm_eo = match->rm_so + strlen(pattern);
406                 return 0;
407         }
408 }
409
410 static int match_one_pattern(struct grep_opt *opt, struct grep_pat *p, char *bol, char *eol)
411 {
412         int hit = 0;
413         regmatch_t pmatch[10];
414
415         if (!opt->fixed) {
416                 regex_t *exp = &p->regexp;
417                 hit = !regexec(exp, bol, ARRAY_SIZE(pmatch),
418                                pmatch, 0);
419         }
420         else {
421                 hit = !fixmatch(p->pattern, bol, pmatch);
422         }
423
424         if (hit && opt->word_regexp) {
425                 /* Match beginning must be either
426                  * beginning of the line, or at word
427                  * boundary (i.e. the last char must
428                  * not be alnum or underscore).
429                  */
430                 if ((pmatch[0].rm_so < 0) ||
431                     (eol - bol) <= pmatch[0].rm_so ||
432                     (pmatch[0].rm_eo < 0) ||
433                     (eol - bol) < pmatch[0].rm_eo)
434                         die("regexp returned nonsense");
435                 if (pmatch[0].rm_so != 0 &&
436                     word_char(bol[pmatch[0].rm_so-1]))
437                         hit = 0;
438                 if (pmatch[0].rm_eo != (eol-bol) &&
439                     word_char(bol[pmatch[0].rm_eo]))
440                         hit = 0;
441         }
442         return hit;
443 }
444
445 static int match_expr_eval(struct grep_opt *opt,
446                            struct grep_expr *x,
447                            char *bol, char *eol)
448 {
449         switch (x->node) {
450         case GREP_NODE_ATOM:
451                 return match_one_pattern(opt, x->u.atom, bol, eol);
452                 break;
453         case GREP_NODE_NOT:
454                 return !match_expr_eval(opt, x->u.unary, bol, eol);
455         case GREP_NODE_AND:
456                 return (match_expr_eval(opt, x->u.binary.left, bol, eol) &&
457                         match_expr_eval(opt, x->u.binary.right, bol, eol));
458         case GREP_NODE_OR:
459                 return (match_expr_eval(opt, x->u.binary.left, bol, eol) ||
460                         match_expr_eval(opt, x->u.binary.right, bol, eol));
461         }
462         die("Unexpected node type (internal error) %d\n", x->node);
463 }
464
465 static int match_expr(struct grep_opt *opt, char *bol, char *eol)
466 {
467         struct grep_expr *x = opt->pattern_expression;
468         return match_expr_eval(opt, x, bol, eol);
469 }
470
471 static int match_line(struct grep_opt *opt, char *bol, char *eol)
472 {
473         struct grep_pat *p;
474         if (opt->extended)
475                 return match_expr(opt, bol, eol);
476         for (p = opt->pattern_list; p; p = p->next) {
477                 if (match_one_pattern(opt, p, bol, eol))
478                         return 1;
479         }
480         return 0;
481 }
482
483 static int grep_buffer(struct grep_opt *opt, const char *name,
484                        char *buf, unsigned long size)
485 {
486         char *bol = buf;
487         unsigned long left = size;
488         unsigned lno = 1;
489         struct pre_context_line {
490                 char *bol;
491                 char *eol;
492         } *prev = NULL, *pcl;
493         unsigned last_hit = 0;
494         unsigned last_shown = 0;
495         int binary_match_only = 0;
496         const char *hunk_mark = "";
497         unsigned count = 0;
498
499         if (buffer_is_binary(buf, size)) {
500                 switch (opt->binary) {
501                 case GREP_BINARY_DEFAULT:
502                         binary_match_only = 1;
503                         break;
504                 case GREP_BINARY_NOMATCH:
505                         return 0; /* Assume unmatch */
506                         break;
507                 default:
508                         break;
509                 }
510         }
511
512         if (opt->pre_context)
513                 prev = xcalloc(opt->pre_context, sizeof(*prev));
514         if (opt->pre_context || opt->post_context)
515                 hunk_mark = "--\n";
516
517         while (left) {
518                 char *eol, ch;
519                 int hit = 0;
520
521                 eol = end_of_line(bol, &left);
522                 ch = *eol;
523                 *eol = 0;
524
525                 hit = match_line(opt, bol, eol);
526
527                 /* "grep -v -e foo -e bla" should list lines
528                  * that do not have either, so inversion should
529                  * be done outside.
530                  */
531                 if (opt->invert)
532                         hit = !hit;
533                 if (opt->unmatch_name_only) {
534                         if (hit)
535                                 return 0;
536                         goto next_line;
537                 }
538                 if (hit) {
539                         count++;
540                         if (binary_match_only) {
541                                 printf("Binary file %s matches\n", name);
542                                 return 1;
543                         }
544                         if (opt->name_only) {
545                                 printf("%s\n", name);
546                                 return 1;
547                         }
548                         /* Hit at this line.  If we haven't shown the
549                          * pre-context lines, we would need to show them.
550                          * When asked to do "count", this still show
551                          * the context which is nonsense, but the user
552                          * deserves to get that ;-).
553                          */
554                         if (opt->pre_context) {
555                                 unsigned from;
556                                 if (opt->pre_context < lno)
557                                         from = lno - opt->pre_context;
558                                 else
559                                         from = 1;
560                                 if (from <= last_shown)
561                                         from = last_shown + 1;
562                                 if (last_shown && from != last_shown + 1)
563                                         printf(hunk_mark);
564                                 while (from < lno) {
565                                         pcl = &prev[lno-from-1];
566                                         show_line(opt, pcl->bol, pcl->eol,
567                                                   name, from, '-');
568                                         from++;
569                                 }
570                                 last_shown = lno-1;
571                         }
572                         if (last_shown && lno != last_shown + 1)
573                                 printf(hunk_mark);
574                         if (!opt->count)
575                                 show_line(opt, bol, eol, name, lno, ':');
576                         last_shown = last_hit = lno;
577                 }
578                 else if (last_hit &&
579                          lno <= last_hit + opt->post_context) {
580                         /* If the last hit is within the post context,
581                          * we need to show this line.
582                          */
583                         if (last_shown && lno != last_shown + 1)
584                                 printf(hunk_mark);
585                         show_line(opt, bol, eol, name, lno, '-');
586                         last_shown = lno;
587                 }
588                 if (opt->pre_context) {
589                         memmove(prev+1, prev,
590                                 (opt->pre_context-1) * sizeof(*prev));
591                         prev->bol = bol;
592                         prev->eol = eol;
593                 }
594
595         next_line:
596                 *eol = ch;
597                 bol = eol + 1;
598                 if (!left)
599                         break;
600                 left--;
601                 lno++;
602         }
603
604         if (opt->unmatch_name_only) {
605                 /* We did not see any hit, so we want to show this */
606                 printf("%s\n", name);
607                 return 1;
608         }
609
610         /* NEEDSWORK:
611          * The real "grep -c foo *.c" gives many "bar.c:0" lines,
612          * which feels mostly useless but sometimes useful.  Maybe
613          * make it another option?  For now suppress them.
614          */
615         if (opt->count && count)
616                 printf("%s:%u\n", name, count);
617         return !!last_hit;
618 }
619
620 static int grep_sha1(struct grep_opt *opt, const unsigned char *sha1, const char *name)
621 {
622         unsigned long size;
623         char *data;
624         char type[20];
625         int hit;
626         data = read_sha1_file(sha1, type, &size);
627         if (!data) {
628                 error("'%s': unable to read %s", name, sha1_to_hex(sha1));
629                 return 0;
630         }
631         hit = grep_buffer(opt, name, data, size);
632         free(data);
633         return hit;
634 }
635
636 static int grep_file(struct grep_opt *opt, const char *filename)
637 {
638         struct stat st;
639         int i;
640         char *data;
641         if (lstat(filename, &st) < 0) {
642         err_ret:
643                 if (errno != ENOENT)
644                         error("'%s': %s", filename, strerror(errno));
645                 return 0;
646         }
647         if (!st.st_size)
648                 return 0; /* empty file -- no grep hit */
649         if (!S_ISREG(st.st_mode))
650                 return 0;
651         i = open(filename, O_RDONLY);
652         if (i < 0)
653                 goto err_ret;
654         data = xmalloc(st.st_size + 1);
655         if (st.st_size != xread(i, data, st.st_size)) {
656                 error("'%s': short read %s", filename, strerror(errno));
657                 close(i);
658                 free(data);
659                 return 0;
660         }
661         close(i);
662         i = grep_buffer(opt, filename, data, st.st_size);
663         free(data);
664         return i;
665 }
666
667 static int exec_grep(int argc, const char **argv)
668 {
669         pid_t pid;
670         int status;
671
672         argv[argc] = NULL;
673         pid = fork();
674         if (pid < 0)
675                 return pid;
676         if (!pid) {
677                 execvp("grep", (char **) argv);
678                 exit(255);
679         }
680         while (waitpid(pid, &status, 0) < 0) {
681                 if (errno == EINTR)
682                         continue;
683                 return -1;
684         }
685         if (WIFEXITED(status)) {
686                 if (!WEXITSTATUS(status))
687                         return 1;
688                 return 0;
689         }
690         return -1;
691 }
692
693 #define MAXARGS 1000
694 #define ARGBUF 4096
695 #define push_arg(a) do { \
696         if (nr < MAXARGS) argv[nr++] = (a); \
697         else die("maximum number of args exceeded"); \
698         } while (0)
699
700 static int external_grep(struct grep_opt *opt, const char **paths, int cached)
701 {
702         int i, nr, argc, hit, len, status;
703         const char *argv[MAXARGS+1];
704         char randarg[ARGBUF];
705         char *argptr = randarg;
706         struct grep_pat *p;
707
708         if (opt->extended)
709                 return -1;
710         len = nr = 0;
711         push_arg("grep");
712         if (opt->fixed)
713                 push_arg("-F");
714         if (opt->linenum)
715                 push_arg("-n");
716         if (opt->regflags & REG_EXTENDED)
717                 push_arg("-E");
718         if (opt->regflags & REG_ICASE)
719                 push_arg("-i");
720         if (opt->word_regexp)
721                 push_arg("-w");
722         if (opt->name_only)
723                 push_arg("-l");
724         if (opt->unmatch_name_only)
725                 push_arg("-L");
726         if (opt->count)
727                 push_arg("-c");
728         if (opt->post_context || opt->pre_context) {
729                 if (opt->post_context != opt->pre_context) {
730                         if (opt->pre_context) {
731                                 push_arg("-B");
732                                 len += snprintf(argptr, sizeof(randarg)-len,
733                                                 "%u", opt->pre_context);
734                                 if (sizeof(randarg) <= len)
735                                         die("maximum length of args exceeded");
736                                 push_arg(argptr);
737                                 argptr += len;
738                         }
739                         if (opt->post_context) {
740                                 push_arg("-A");
741                                 len += snprintf(argptr, sizeof(randarg)-len,
742                                                 "%u", opt->post_context);
743                                 if (sizeof(randarg) <= len)
744                                         die("maximum length of args exceeded");
745                                 push_arg(argptr);
746                                 argptr += len;
747                         }
748                 }
749                 else {
750                         push_arg("-C");
751                         len += snprintf(argptr, sizeof(randarg)-len,
752                                         "%u", opt->post_context);
753                         if (sizeof(randarg) <= len)
754                                 die("maximum length of args exceeded");
755                         push_arg(argptr);
756                         argptr += len;
757                 }
758         }
759         for (p = opt->pattern_list; p; p = p->next) {
760                 push_arg("-e");
761                 push_arg(p->pattern);
762         }
763
764         /*
765          * To make sure we get the header printed out when we want it,
766          * add /dev/null to the paths to grep.  This is unnecessary
767          * (and wrong) with "-l" or "-L", which always print out the
768          * name anyway.
769          *
770          * GNU grep has "-H", but this is portable.
771          */
772         if (!opt->name_only && !opt->unmatch_name_only)
773                 push_arg("/dev/null");
774
775         hit = 0;
776         argc = nr;
777         for (i = 0; i < active_nr; i++) {
778                 struct cache_entry *ce = active_cache[i];
779                 char *name;
780                 if (ce_stage(ce) || !S_ISREG(ntohl(ce->ce_mode)))
781                         continue;
782                 if (!pathspec_matches(paths, ce->name))
783                         continue;
784                 name = ce->name;
785                 if (name[0] == '-') {
786                         int len = ce_namelen(ce);
787                         name = xmalloc(len + 3);
788                         memcpy(name, "./", 2);
789                         memcpy(name + 2, ce->name, len + 1);
790                 }
791                 argv[argc++] = name;
792                 if (argc < MAXARGS)
793                         continue;
794                 status = exec_grep(argc, argv);
795                 if (0 < status)
796                         hit = 1;
797                 argc = nr;
798         }
799         if (argc > nr) {
800                 status = exec_grep(argc, argv);
801                 if (0 < status)
802                         hit = 1;
803         }
804         return hit;
805 }
806
807 static int grep_cache(struct grep_opt *opt, const char **paths, int cached)
808 {
809         int hit = 0;
810         int nr;
811         read_cache();
812
813 #ifdef __unix__
814         /*
815          * Use the external "grep" command for the case where
816          * we grep through the checked-out files. It tends to
817          * be a lot more optimized
818          */
819         if (!cached) {
820                 hit = external_grep(opt, paths, cached);
821                 if (hit >= 0)
822                         return hit;
823         }
824 #endif
825
826         for (nr = 0; nr < active_nr; nr++) {
827                 struct cache_entry *ce = active_cache[nr];
828                 if (ce_stage(ce) || !S_ISREG(ntohl(ce->ce_mode)))
829                         continue;
830                 if (!pathspec_matches(paths, ce->name))
831                         continue;
832                 if (cached)
833                         hit |= grep_sha1(opt, ce->sha1, ce->name);
834                 else
835                         hit |= grep_file(opt, ce->name);
836         }
837         return hit;
838 }
839
840 static int grep_tree(struct grep_opt *opt, const char **paths,
841                      struct tree_desc *tree,
842                      const char *tree_name, const char *base)
843 {
844         int len;
845         int hit = 0;
846         struct name_entry entry;
847         char *down;
848         char *path_buf = xmalloc(PATH_MAX + strlen(tree_name) + 100);
849
850         if (tree_name[0]) {
851                 int offset = sprintf(path_buf, "%s:", tree_name);
852                 down = path_buf + offset;
853                 strcat(down, base);
854         }
855         else {
856                 down = path_buf;
857                 strcpy(down, base);
858         }
859         len = strlen(path_buf);
860
861         while (tree_entry(tree, &entry)) {
862                 strcpy(path_buf + len, entry.path);
863
864                 if (S_ISDIR(entry.mode))
865                         /* Match "abc/" against pathspec to
866                          * decide if we want to descend into "abc"
867                          * directory.
868                          */
869                         strcpy(path_buf + len + entry.pathlen, "/");
870
871                 if (!pathspec_matches(paths, down))
872                         ;
873                 else if (S_ISREG(entry.mode))
874                         hit |= grep_sha1(opt, entry.sha1, path_buf);
875                 else if (S_ISDIR(entry.mode)) {
876                         char type[20];
877                         struct tree_desc sub;
878                         void *data;
879                         data = read_sha1_file(entry.sha1, type, &sub.size);
880                         if (!data)
881                                 die("unable to read tree (%s)",
882                                     sha1_to_hex(entry.sha1));
883                         sub.buf = data;
884                         hit |= grep_tree(opt, paths, &sub, tree_name, down);
885                         free(data);
886                 }
887         }
888         return hit;
889 }
890
891 static int grep_object(struct grep_opt *opt, const char **paths,
892                        struct object *obj, const char *name)
893 {
894         if (obj->type == TYPE_BLOB)
895                 return grep_sha1(opt, obj->sha1, name);
896         if (obj->type == TYPE_COMMIT || obj->type == TYPE_TREE) {
897                 struct tree_desc tree;
898                 void *data;
899                 int hit;
900                 data = read_object_with_reference(obj->sha1, tree_type,
901                                                   &tree.size, NULL);
902                 if (!data)
903                         die("unable to read tree (%s)", sha1_to_hex(obj->sha1));
904                 tree.buf = data;
905                 hit = grep_tree(opt, paths, &tree, name, "");
906                 free(data);
907                 return hit;
908         }
909         die("unable to grep from object of type %s", typename(obj->type));
910 }
911
912 static const char builtin_grep_usage[] =
913 "git-grep <option>* <rev>* [-e] <pattern> [<path>...]";
914
915 static const char emsg_invalid_context_len[] =
916 "%s: invalid context length argument";
917 static const char emsg_missing_context_len[] =
918 "missing context length argument";
919 static const char emsg_missing_argument[] =
920 "option requires an argument -%s";
921
922 int cmd_grep(int argc, const char **argv, char **envp)
923 {
924         int hit = 0;
925         int cached = 0;
926         int seen_dashdash = 0;
927         struct grep_opt opt;
928         struct object_array list = { 0, 0, NULL };
929         const char *prefix = setup_git_directory();
930         const char **paths = NULL;
931         int i;
932
933         memset(&opt, 0, sizeof(opt));
934         opt.pattern_tail = &opt.pattern_list;
935         opt.regflags = REG_NEWLINE;
936
937         /*
938          * If there is no -- then the paths must exist in the working
939          * tree.  If there is no explicit pattern specified with -e or
940          * -f, we take the first unrecognized non option to be the
941          * pattern, but then what follows it must be zero or more
942          * valid refs up to the -- (if exists), and then existing
943          * paths.  If there is an explicit pattern, then the first
944          * unrecocnized non option is the beginning of the refs list
945          * that continues up to the -- (if exists), and then paths.
946          */
947
948         while (1 < argc) {
949                 const char *arg = argv[1];
950                 argc--; argv++;
951                 if (!strcmp("--cached", arg)) {
952                         cached = 1;
953                         continue;
954                 }
955                 if (!strcmp("-a", arg) ||
956                     !strcmp("--text", arg)) {
957                         opt.binary = GREP_BINARY_TEXT;
958                         continue;
959                 }
960                 if (!strcmp("-i", arg) ||
961                     !strcmp("--ignore-case", arg)) {
962                         opt.regflags |= REG_ICASE;
963                         continue;
964                 }
965                 if (!strcmp("-I", arg)) {
966                         opt.binary = GREP_BINARY_NOMATCH;
967                         continue;
968                 }
969                 if (!strcmp("-v", arg) ||
970                     !strcmp("--invert-match", arg)) {
971                         opt.invert = 1;
972                         continue;
973                 }
974                 if (!strcmp("-E", arg) ||
975                     !strcmp("--extended-regexp", arg)) {
976                         opt.regflags |= REG_EXTENDED;
977                         continue;
978                 }
979                 if (!strcmp("-F", arg) ||
980                     !strcmp("--fixed-strings", arg)) {
981                         opt.fixed = 1;
982                         continue;
983                 }
984                 if (!strcmp("-G", arg) ||
985                     !strcmp("--basic-regexp", arg)) {
986                         opt.regflags &= ~REG_EXTENDED;
987                         continue;
988                 }
989                 if (!strcmp("-n", arg)) {
990                         opt.linenum = 1;
991                         continue;
992                 }
993                 if (!strcmp("-H", arg)) {
994                         /* We always show the pathname, so this
995                          * is a noop.
996                          */
997                         continue;
998                 }
999                 if (!strcmp("-l", arg) ||
1000                     !strcmp("--files-with-matches", arg)) {
1001                         opt.name_only = 1;
1002                         continue;
1003                 }
1004                 if (!strcmp("-L", arg) ||
1005                     !strcmp("--files-without-match", arg)) {
1006                         opt.unmatch_name_only = 1;
1007                         continue;
1008                 }
1009                 if (!strcmp("-c", arg) ||
1010                     !strcmp("--count", arg)) {
1011                         opt.count = 1;
1012                         continue;
1013                 }
1014                 if (!strcmp("-w", arg) ||
1015                     !strcmp("--word-regexp", arg)) {
1016                         opt.word_regexp = 1;
1017                         continue;
1018                 }
1019                 if (!strncmp("-A", arg, 2) ||
1020                     !strncmp("-B", arg, 2) ||
1021                     !strncmp("-C", arg, 2) ||
1022                     (arg[0] == '-' && '1' <= arg[1] && arg[1] <= '9')) {
1023                         unsigned num;
1024                         const char *scan;
1025                         switch (arg[1]) {
1026                         case 'A': case 'B': case 'C':
1027                                 if (!arg[2]) {
1028                                         if (argc <= 1)
1029                                                 die(emsg_missing_context_len);
1030                                         scan = *++argv;
1031                                         argc--;
1032                                 }
1033                                 else
1034                                         scan = arg + 2;
1035                                 break;
1036                         default:
1037                                 scan = arg + 1;
1038                                 break;
1039                         }
1040                         if (sscanf(scan, "%u", &num) != 1)
1041                                 die(emsg_invalid_context_len, scan);
1042                         switch (arg[1]) {
1043                         case 'A':
1044                                 opt.post_context = num;
1045                                 break;
1046                         default:
1047                         case 'C':
1048                                 opt.post_context = num;
1049                         case 'B':
1050                                 opt.pre_context = num;
1051                                 break;
1052                         }
1053                         continue;
1054                 }
1055                 if (!strcmp("-f", arg)) {
1056                         FILE *patterns;
1057                         int lno = 0;
1058                         char buf[1024];
1059                         if (argc <= 1)
1060                                 die(emsg_missing_argument, arg);
1061                         patterns = fopen(argv[1], "r");
1062                         if (!patterns)
1063                                 die("'%s': %s", argv[1], strerror(errno));
1064                         while (fgets(buf, sizeof(buf), patterns)) {
1065                                 int len = strlen(buf);
1066                                 if (buf[len-1] == '\n')
1067                                         buf[len-1] = 0;
1068                                 /* ignore empty line like grep does */
1069                                 if (!buf[0])
1070                                         continue;
1071                                 add_pattern(&opt, strdup(buf), argv[1], ++lno,
1072                                             GREP_PATTERN);
1073                         }
1074                         fclose(patterns);
1075                         argv++;
1076                         argc--;
1077                         continue;
1078                 }
1079                 if (!strcmp("--not", arg)) {
1080                         add_pattern(&opt, arg, "command line", 0, GREP_NOT);
1081                         continue;
1082                 }
1083                 if (!strcmp("--and", arg)) {
1084                         add_pattern(&opt, arg, "command line", 0, GREP_AND);
1085                         continue;
1086                 }
1087                 if (!strcmp("--or", arg))
1088                         continue; /* no-op */
1089                 if (!strcmp("(", arg)) {
1090                         add_pattern(&opt, arg, "command line", 0, GREP_OPEN_PAREN);
1091                         continue;
1092                 }
1093                 if (!strcmp(")", arg)) {
1094                         add_pattern(&opt, arg, "command line", 0, GREP_CLOSE_PAREN);
1095                         continue;
1096                 }
1097                 if (!strcmp("-e", arg)) {
1098                         if (1 < argc) {
1099                                 add_pattern(&opt, argv[1], "-e option", 0,
1100                                             GREP_PATTERN);
1101                                 argv++;
1102                                 argc--;
1103                                 continue;
1104                         }
1105                         die(emsg_missing_argument, arg);
1106                 }
1107                 if (!strcmp("--", arg)) {
1108                         /* later processing wants to have this at argv[1] */
1109                         argv--;
1110                         argc++;
1111                         break;
1112                 }
1113                 if (*arg == '-')
1114                         usage(builtin_grep_usage);
1115
1116                 /* First unrecognized non-option token */
1117                 if (!opt.pattern_list) {
1118                         add_pattern(&opt, arg, "command line", 0,
1119                                     GREP_PATTERN);
1120                         break;
1121                 }
1122                 else {
1123                         /* We are looking at the first path or rev;
1124                          * it is found at argv[1] after leaving the
1125                          * loop.
1126                          */
1127                         argc++; argv--;
1128                         break;
1129                 }
1130         }
1131
1132         if (!opt.pattern_list)
1133                 die("no pattern given.");
1134         if ((opt.regflags != REG_NEWLINE) && opt.fixed)
1135                 die("cannot mix --fixed-strings and regexp");
1136         if (!opt.fixed)
1137                 compile_patterns(&opt);
1138
1139         /* Check revs and then paths */
1140         for (i = 1; i < argc; i++) {
1141                 const char *arg = argv[i];
1142                 unsigned char sha1[20];
1143                 /* Is it a rev? */
1144                 if (!get_sha1(arg, sha1)) {
1145                         struct object *object = parse_object(sha1);
1146                         if (!object)
1147                                 die("bad object %s", arg);
1148                         add_object_array(object, arg, &list);
1149                         continue;
1150                 }
1151                 if (!strcmp(arg, "--")) {
1152                         i++;
1153                         seen_dashdash = 1;
1154                 }
1155                 break;
1156         }
1157
1158         /* The rest are paths */
1159         if (!seen_dashdash) {
1160                 int j;
1161                 for (j = i; j < argc; j++)
1162                         verify_filename(prefix, argv[j]);
1163         }
1164
1165         if (i < argc)
1166                 paths = get_pathspec(prefix, argv + i);
1167         else if (prefix) {
1168                 paths = xcalloc(2, sizeof(const char *));
1169                 paths[0] = prefix;
1170                 paths[1] = NULL;
1171         }
1172
1173         if (!list.nr)
1174                 return !grep_cache(&opt, paths, cached);
1175
1176         if (cached)
1177                 die("both --cached and trees are given.");
1178
1179         for (i = 0; i < list.nr; i++) {
1180                 struct object *real_obj;
1181                 real_obj = deref_tag(list.objects[i].item, NULL, 0);
1182                 if (grep_object(&opt, paths, real_obj, list.objects[i].name))
1183                         hit = 1;
1184         }
1185         return !hit;
1186 }