builtin-grep.c

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