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