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 }