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 /*
  16  * git grep pathspecs are somewhat different from diff-tree pathspecs;
  17  * pathname wildcards are allowed.
  18  */
  19 static int pathspec_matches(const char **paths, const char *name)
  20 {
  21         int namelen, i;
  22         if (!paths || !*paths)
  23                 return 1;
  24         namelen = strlen(name);
  25         for (i = 0; paths[i]; i++) {
  26                 const char *match = paths[i];
  27                 int matchlen = strlen(match);
  28                 const char *cp, *meta;
  29
  30                 if (!matchlen ||
  31                     ((matchlen <= namelen) &&
  32                      !strncmp(name, match, matchlen) &&
  33                      (match[matchlen-1] == '/' ||
  34                       name[matchlen] == '\0' || name[matchlen] == '/')))
  35                         return 1;
  36                 if (!fnmatch(match, name, 0))
  37                         return 1;
  38                 if (name[namelen-1] != '/')
  39                         continue;
  40
  41                 /* We are being asked if the directory ("name") is worth
  42                  * descending into.
  43                  *
  44                  * Find the longest leading directory name that does
  45                  * not have metacharacter in the pathspec; the name
  46                  * we are looking at must overlap with that directory.
  47                  */
  48                 for (cp = match, meta = NULL; cp - match < matchlen; cp++) {
  49                         char ch = *cp;
  50                         if (ch == '*' || ch == '[' || ch == '?') {
  51                                 meta = cp;
  52                                 break;
  53                         }
  54                 }
  55                 if (!meta)
  56                         meta = cp; /* fully literal */
  57
  58                 if (namelen <= meta - match) {
  59                         /* Looking at "Documentation/" and
  60                          * the pattern says "Documentation/howto/", or
  61                          * "Documentation/diff*.txt".  The name we
  62                          * have should match prefix.
  63                          */
  64                         if (!memcmp(match, name, namelen))
  65                                 return 1;
  66                         continue;
  67                 }
  68
  69                 if (meta - match < namelen) {
  70                         /* Looking at "Documentation/howto/" and
  71                          * the pattern says "Documentation/h*";
  72                          * match up to "Do.../h"; this avoids descending
  73                          * into "Documentation/technical/".
  74                          */
  75                         if (!memcmp(match, name, meta - match))
  76                                 return 1;
  77                         continue;
  78                 }
  79         }
  80         return 0;
  81 }
  82
  83 static int grep_sha1(struct grep_opt *opt, const unsigned char *sha1, const char *name, int tree_name_len)
  84 {
  85         unsigned long size;
  86         char *data;
  87         enum object_type type;
  88         char *to_free = NULL;
  89         int hit;
  90
  91         data = read_sha1_file(sha1, &type, &size);
  92         if (!data) {
  93                 error("'%s': unable to read %s", name, sha1_to_hex(sha1));
  94                 return 0;
  95         }
  96         if (opt->relative && opt->prefix_length) {
  97                 static char name_buf[PATH_MAX];
  98                 char *cp;
  99                 int name_len = strlen(name) - opt->prefix_length + 1;
 100
 101                 if (!tree_name_len)
 102                         name += opt->prefix_length;
 103                 else {
 104                         if (ARRAY_SIZE(name_buf) <= name_len)
 105                                 cp = to_free = xmalloc(name_len);
 106                         else
 107                                 cp = name_buf;
 108                         memcpy(cp, name, tree_name_len);
 109                         strcpy(cp + tree_name_len,
 110                                name + tree_name_len + opt->prefix_length);
 111                         name = cp;
 112                 }
 113         }
 114         hit = grep_buffer(opt, name, data, size);
 115         free(data);
 116         free(to_free);
 117         return hit;
 118 }
 119
 120 static int grep_file(struct grep_opt *opt, const char *filename)
 121 {
 122         struct stat st;
 123         int i;
 124         char *data;
 125         size_t sz;
 126
 127         if (lstat(filename, &st) < 0) {
 128         err_ret:
 129                 if (errno != ENOENT)
 130                         error("'%s': %s", filename, strerror(errno));
 131                 return 0;
 132         }
 133         if (!st.st_size)
 134                 return 0; /* empty file -- no grep hit */
 135         if (!S_ISREG(st.st_mode))
 136                 return 0;
 137         sz = xsize_t(st.st_size);
 138         i = open(filename, O_RDONLY);
 139         if (i < 0)
 140                 goto err_ret;
 141         data = xmalloc(sz + 1);
 142         if (st.st_size != read_in_full(i, data, sz)) {
 143                 error("'%s': short read %s", filename, strerror(errno));
 144                 close(i);
 145                 free(data);
 146                 return 0;
 147         }
 148         close(i);
 149         if (opt->relative && opt->prefix_length)
 150                 filename += opt->prefix_length;
 151         i = grep_buffer(opt, filename, data, sz);
 152         free(data);
 153         return i;
 154 }
 155
 156 #ifdef __unix__
 157 static int exec_grep(int argc, const char **argv)
 158 {
 159         pid_t pid;
 160         int status;
 161
 162         argv[argc] = NULL;
 163         pid = fork();
 164         if (pid < 0)
 165                 return pid;
 166         if (!pid) {
 167                 execvp("grep", (char **) argv);
 168                 exit(255);
 169         }
 170         while (waitpid(pid, &status, 0) < 0) {
 171                 if (errno == EINTR)
 172                         continue;
 173                 return -1;
 174         }
 175         if (WIFEXITED(status)) {
 176                 if (!WEXITSTATUS(status))
 177                         return 1;
 178                 return 0;
 179         }
 180         return -1;
 181 }
 182
 183 #define MAXARGS 1000
 184 #define ARGBUF 4096
 185 #define push_arg(a) do { \
 186         if (nr < MAXARGS) argv[nr++] = (a); \
 187         else die("maximum number of args exceeded"); \
 188         } while (0)
 189
 190 /*
 191  * If you send a singleton filename to grep, it does not give
 192  * the name of the file.  GNU grep has "-H" but we would want
 193  * that behaviour in a portable way.
 194  *
 195  * So we keep two pathnames in argv buffer unsent to grep in
 196  * the main loop if we need to do more than one grep.
 197  */
 198 static int flush_grep(struct grep_opt *opt,
 199                       int argc, int arg0, const char **argv, int *kept)
 200 {
 201         int status;
 202         int count = argc - arg0;
 203         const char *kept_0 = NULL;
 204
 205         if (count <= 2) {
 206                 /*
 207                  * Because we keep at least 2 paths in the call from
 208                  * the main loop (i.e. kept != NULL), and MAXARGS is
 209                  * far greater than 2, this usually is a call to
 210                  * conclude the grep.  However, the user could attempt
 211                  * to overflow the argv buffer by giving too many
 212                  * options to leave very small number of real
 213                  * arguments even for the call in the main loop.
 214                  */
 215                 if (kept)
 216                         die("insanely many options to grep");
 217
 218                 /*
 219                  * If we have two or more paths, we do not have to do
 220                  * anything special, but we need to push /dev/null to
 221                  * get "-H" behaviour of GNU grep portably but when we
 222                  * are not doing "-l" nor "-L" nor "-c".
 223                  */
 224                 if (count == 1 &&
 225                     !opt->name_only &&
 226                     !opt->unmatch_name_only &&
 227                     !opt->count) {
 228                         argv[argc++] = "/dev/null";
 229                         argv[argc] = NULL;
 230                 }
 231         }
 232
 233         else if (kept) {
 234                 /*
 235                  * Called because we found many paths and haven't finished
 236                  * iterating over the cache yet.  We keep two paths
 237                  * for the concluding call.  argv[argc-2] and argv[argc-1]
 238                  * has the last two paths, so save the first one away,
 239                  * replace it with NULL while sending the list to grep,
 240                  * and recover them after we are done.
 241                  */
 242                 *kept = 2;
 243                 kept_0 = argv[argc-2];
 244                 argv[argc-2] = NULL;
 245                 argc -= 2;
 246         }
 247
 248         status = exec_grep(argc, argv);
 249
 250         if (kept_0) {
 251                 /*
 252                  * Then recover them.  Now the last arg is beyond the
 253                  * terminating NULL which is at argc, and the second
 254                  * from the last is what we saved away in kept_0
 255                  */
 256                 argv[arg0++] = kept_0;
 257                 argv[arg0] = argv[argc+1];
 258         }
 259         return status;
 260 }
 261
 262 static int external_grep(struct grep_opt *opt, const char **paths, int cached)
 263 {
 264         int i, nr, argc, hit, len, status;
 265         const char *argv[MAXARGS+1];
 266         char randarg[ARGBUF];
 267         char *argptr = randarg;
 268         struct grep_pat *p;
 269
 270         if (opt->extended || (opt->relative && opt->prefix_length))
 271                 return -1;
 272         len = nr = 0;
 273         push_arg("grep");
 274         if (opt->fixed)
 275                 push_arg("-F");
 276         if (opt->linenum)
 277                 push_arg("-n");
 278         if (!opt->pathname)
 279                 push_arg("-h");
 280         if (opt->regflags & REG_EXTENDED)
 281                 push_arg("-E");
 282         if (opt->regflags & REG_ICASE)
 283                 push_arg("-i");
 284         if (opt->word_regexp)
 285                 push_arg("-w");
 286         if (opt->name_only)
 287                 push_arg("-l");
 288         if (opt->unmatch_name_only)
 289                 push_arg("-L");
 290         if (opt->count)
 291                 push_arg("-c");
 292         if (opt->post_context || opt->pre_context) {
 293                 if (opt->post_context != opt->pre_context) {
 294                         if (opt->pre_context) {
 295                                 push_arg("-B");
 296                                 len += snprintf(argptr, sizeof(randarg)-len,
 297                                                 "%u", opt->pre_context) + 1;
 298                                 if (sizeof(randarg) <= len)
 299                                         die("maximum length of args exceeded");
 300                                 push_arg(argptr);
 301                                 argptr += len;
 302                         }
 303                         if (opt->post_context) {
 304                                 push_arg("-A");
 305                                 len += snprintf(argptr, sizeof(randarg)-len,
 306                                                 "%u", opt->post_context) + 1;
 307                                 if (sizeof(randarg) <= len)
 308                                         die("maximum length of args exceeded");
 309                                 push_arg(argptr);
 310                                 argptr += len;
 311                         }
 312                 }
 313                 else {
 314                         push_arg("-C");
 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         for (p = opt->pattern_list; p; p = p->next) {
 324                 push_arg("-e");
 325                 push_arg(p->pattern);
 326         }
 327
 328         hit = 0;
 329         argc = nr;
 330         for (i = 0; i < active_nr; i++) {
 331                 struct cache_entry *ce = active_cache[i];
 332                 char *name;
 333                 int kept;
 334                 if (!S_ISREG(ntohl(ce->ce_mode)))
 335                         continue;
 336                 if (!pathspec_matches(paths, ce->name))
 337                         continue;
 338                 name = ce->name;
 339                 if (name[0] == '-') {
 340                         int len = ce_namelen(ce);
 341                         name = xmalloc(len + 3);
 342                         memcpy(name, "./", 2);
 343                         memcpy(name + 2, ce->name, len + 1);
 344                 }
 345                 argv[argc++] = name;
 346                 if (MAXARGS <= argc) {
 347                         status = flush_grep(opt, argc, nr, argv, &kept);
 348                         if (0 < status)
 349                                 hit = 1;
 350                         argc = nr + kept;
 351                 }
 352                 if (ce_stage(ce)) {
 353                         do {
 354                                 i++;
 355                         } while (i < active_nr &&
 356                                  !strcmp(ce->name, active_cache[i]->name));
 357                         i--; /* compensate for loop control */
 358                 }
 359         }
 360         if (argc > nr) {
 361                 status = flush_grep(opt, argc, nr, argv, NULL);
 362                 if (0 < status)
 363                         hit = 1;
 364         }
 365         return hit;
 366 }
 367 #endif
 368
 369 static int grep_cache(struct grep_opt *opt, const char **paths, int cached)
 370 {
 371         int hit = 0;
 372         int nr;
 373         read_cache();
 374
 375 #ifdef __unix__
 376         /*
 377          * Use the external "grep" command for the case where
 378          * we grep through the checked-out files. It tends to
 379          * be a lot more optimized
 380          */
 381         if (!cached) {
 382                 hit = external_grep(opt, paths, cached);
 383                 if (hit >= 0)
 384                         return hit;
 385         }
 386 #endif
 387
 388         for (nr = 0; nr < active_nr; nr++) {
 389                 struct cache_entry *ce = active_cache[nr];
 390                 if (!S_ISREG(ntohl(ce->ce_mode)))
 391                         continue;
 392                 if (!pathspec_matches(paths, ce->name))
 393                         continue;
 394                 if (cached) {
 395                         if (ce_stage(ce))
 396                                 continue;
 397                         hit |= grep_sha1(opt, ce->sha1, ce->name, 0);
 398                 }
 399                 else
 400                         hit |= grep_file(opt, ce->name);
 401                 if (ce_stage(ce)) {
 402                         do {
 403                                 nr++;
 404                         } while (nr < active_nr &&
 405                                  !strcmp(ce->name, active_cache[nr]->name));
 406                         nr--; /* compensate for loop control */
 407                 }
 408         }
 409         free_grep_patterns(opt);
 410         return hit;
 411 }
 412
 413 static int grep_tree(struct grep_opt *opt, const char **paths,
 414                      struct tree_desc *tree,
 415                      const char *tree_name, const char *base)
 416 {
 417         int len;
 418         int hit = 0;
 419         struct name_entry entry;
 420         char *down;
 421         int tn_len = strlen(tree_name);
 422         char *path_buf = xmalloc(PATH_MAX + tn_len + 100);
 423
 424         if (tn_len) {
 425                 tn_len = sprintf(path_buf, "%s:", tree_name);
 426                 down = path_buf + tn_len;
 427                 strcat(down, base);
 428         }
 429         else {
 430                 down = path_buf;
 431                 strcpy(down, base);
 432         }
 433         len = strlen(path_buf);
 434
 435         while (tree_entry(tree, &entry)) {
 436                 strcpy(path_buf + len, entry.path);
 437
 438                 if (S_ISDIR(entry.mode))
 439                         /* Match "abc/" against pathspec to
 440                          * decide if we want to descend into "abc"
 441                          * directory.
 442                          */
 443                         strcpy(path_buf + len + tree_entry_len(entry.path, entry.sha1), "/");
 444
 445                 if (!pathspec_matches(paths, down))
 446                         ;
 447                 else if (S_ISREG(entry.mode))
 448                         hit |= grep_sha1(opt, entry.sha1, path_buf, tn_len);
 449                 else if (S_ISDIR(entry.mode)) {
 450                         enum object_type type;
 451                         struct tree_desc sub;
 452                         void *data;
 453                         unsigned long size;
 454
 455                         data = read_sha1_file(entry.sha1, &type, &size);
 456                         if (!data)
 457                                 die("unable to read tree (%s)",
 458                                     sha1_to_hex(entry.sha1));
 459                         init_tree_desc(&sub, data, size);
 460                         hit |= grep_tree(opt, paths, &sub, tree_name, down);
 461                         free(data);
 462                 }
 463         }
 464         return hit;
 465 }
 466
 467 static int grep_object(struct grep_opt *opt, const char **paths,
 468                        struct object *obj, const char *name)
 469 {
 470         if (obj->type == OBJ_BLOB)
 471                 return grep_sha1(opt, obj->sha1, name, 0);
 472         if (obj->type == OBJ_COMMIT || obj->type == OBJ_TREE) {
 473                 struct tree_desc tree;
 474                 void *data;
 475                 unsigned long size;
 476                 int hit;
 477                 data = read_object_with_reference(obj->sha1, tree_type,
 478                                                   &size, NULL);
 479                 if (!data)
 480                         die("unable to read tree (%s)", sha1_to_hex(obj->sha1));
 481                 init_tree_desc(&tree, data, size);
 482                 hit = grep_tree(opt, paths, &tree, name, "");
 483                 free(data);
 484                 return hit;
 485         }
 486         die("unable to grep from object of type %s", typename(obj->type));
 487 }
 488
 489 static const char builtin_grep_usage[] =
 490 "git-grep <option>* <rev>* [-e] <pattern> [<path>...]";
 491
 492 static const char emsg_invalid_context_len[] =
 493 "%s: invalid context length argument";
 494 static const char emsg_missing_context_len[] =
 495 "missing context length argument";
 496 static const char emsg_missing_argument[] =
 497 "option requires an argument -%s";
 498
 499 int cmd_grep(int argc, const char **argv, const char *prefix)
 500 {
 501         int hit = 0;
 502         int cached = 0;
 503         int seen_dashdash = 0;
 504         struct grep_opt opt;
 505         struct object_array list = { 0, 0, NULL };
 506         const char **paths = NULL;
 507         int i;
 508
 509         memset(&opt, 0, sizeof(opt));
 510         opt.prefix_length = (prefix && *prefix) ? strlen(prefix) : 0;
 511         opt.relative = 1;
 512         opt.pathname = 1;
 513         opt.pattern_tail = &opt.pattern_list;
 514         opt.regflags = REG_NEWLINE;
 515
 516         /*
 517          * If there is no -- then the paths must exist in the working
 518          * tree.  If there is no explicit pattern specified with -e or
 519          * -f, we take the first unrecognized non option to be the
 520          * pattern, but then what follows it must be zero or more
 521          * valid refs up to the -- (if exists), and then existing
 522          * paths.  If there is an explicit pattern, then the first
 523          * unrecognized non option is the beginning of the refs list
 524          * that continues up to the -- (if exists), and then paths.
 525          */
 526
 527         while (1 < argc) {
 528                 const char *arg = argv[1];
 529                 argc--; argv++;
 530                 if (!strcmp("--cached", arg)) {
 531                         cached = 1;
 532                         continue;
 533                 }
 534                 if (!strcmp("-a", arg) ||
 535                     !strcmp("--text", arg)) {
 536                         opt.binary = GREP_BINARY_TEXT;
 537                         continue;
 538                 }
 539                 if (!strcmp("-i", arg) ||
 540                     !strcmp("--ignore-case", arg)) {
 541                         opt.regflags |= REG_ICASE;
 542                         continue;
 543                 }
 544                 if (!strcmp("-I", arg)) {
 545                         opt.binary = GREP_BINARY_NOMATCH;
 546                         continue;
 547                 }
 548                 if (!strcmp("-v", arg) ||
 549                     !strcmp("--invert-match", arg)) {
 550                         opt.invert = 1;
 551                         continue;
 552                 }
 553                 if (!strcmp("-E", arg) ||
 554                     !strcmp("--extended-regexp", arg)) {
 555                         opt.regflags |= REG_EXTENDED;
 556                         continue;
 557                 }
 558                 if (!strcmp("-F", arg) ||
 559                     !strcmp("--fixed-strings", arg)) {
 560                         opt.fixed = 1;
 561                         continue;
 562                 }
 563                 if (!strcmp("-G", arg) ||
 564                     !strcmp("--basic-regexp", arg)) {
 565                         opt.regflags &= ~REG_EXTENDED;
 566                         continue;
 567                 }
 568                 if (!strcmp("-n", arg)) {
 569                         opt.linenum = 1;
 570                         continue;
 571                 }
 572                 if (!strcmp("-h", arg)) {
 573                         opt.pathname = 0;
 574                         continue;
 575                 }
 576                 if (!strcmp("-H", arg)) {
 577                         opt.pathname = 1;
 578                         continue;
 579                 }
 580                 if (!strcmp("-l", arg) ||
 581                     !strcmp("--files-with-matches", arg)) {
 582                         opt.name_only = 1;
 583                         continue;
 584                 }
 585                 if (!strcmp("-L", arg) ||
 586                     !strcmp("--files-without-match", arg)) {
 587                         opt.unmatch_name_only = 1;
 588                         continue;
 589                 }
 590                 if (!strcmp("-c", arg) ||
 591                     !strcmp("--count", arg)) {
 592                         opt.count = 1;
 593                         continue;
 594                 }
 595                 if (!strcmp("-w", arg) ||
 596                     !strcmp("--word-regexp", arg)) {
 597                         opt.word_regexp = 1;
 598                         continue;
 599                 }
 600                 if (!prefixcmp(arg, "-A") ||
 601                     !prefixcmp(arg, "-B") ||
 602                     !prefixcmp(arg, "-C") ||
 603                     (arg[0] == '-' && '1' <= arg[1] && arg[1] <= '9')) {
 604                         unsigned num;
 605                         const char *scan;
 606                         switch (arg[1]) {
 607                         case 'A': case 'B': case 'C':
 608                                 if (!arg[2]) {
 609                                         if (argc <= 1)
 610                                                 die(emsg_missing_context_len);
 611                                         scan = *++argv;
 612                                         argc--;
 613                                 }
 614                                 else
 615                                         scan = arg + 2;
 616                                 break;
 617                         default:
 618                                 scan = arg + 1;
 619                                 break;
 620                         }
 621                         if (strtoul_ui(scan, 10, &num))
 622                                 die(emsg_invalid_context_len, scan);
 623                         switch (arg[1]) {
 624                         case 'A':
 625                                 opt.post_context = num;
 626                                 break;
 627                         default:
 628                         case 'C':
 629                                 opt.post_context = num;
 630                         case 'B':
 631                                 opt.pre_context = num;
 632                                 break;
 633                         }
 634                         continue;
 635                 }
 636                 if (!strcmp("-f", arg)) {
 637                         FILE *patterns;
 638                         int lno = 0;
 639                         char buf[1024];
 640                         if (argc <= 1)
 641                                 die(emsg_missing_argument, arg);
 642                         patterns = fopen(argv[1], "r");
 643                         if (!patterns)
 644                                 die("'%s': %s", argv[1], strerror(errno));
 645                         while (fgets(buf, sizeof(buf), patterns)) {
 646                                 int len = strlen(buf);
 647                                 if (buf[len-1] == '\n')
 648                                         buf[len-1] = 0;
 649                                 /* ignore empty line like grep does */
 650                                 if (!buf[0])
 651                                         continue;
 652                                 append_grep_pattern(&opt, xstrdup(buf),
 653                                                     argv[1], ++lno,
 654                                                     GREP_PATTERN);
 655                         }
 656                         fclose(patterns);
 657                         argv++;
 658                         argc--;
 659                         continue;
 660                 }
 661                 if (!strcmp("--not", arg)) {
 662                         append_grep_pattern(&opt, arg, "command line", 0,
 663                                             GREP_NOT);
 664                         continue;
 665                 }
 666                 if (!strcmp("--and", arg)) {
 667                         append_grep_pattern(&opt, arg, "command line", 0,
 668                                             GREP_AND);
 669                         continue;
 670                 }
 671                 if (!strcmp("--or", arg))
 672                         continue; /* no-op */
 673                 if (!strcmp("(", arg)) {
 674                         append_grep_pattern(&opt, arg, "command line", 0,
 675                                             GREP_OPEN_PAREN);
 676                         continue;
 677                 }
 678                 if (!strcmp(")", arg)) {
 679                         append_grep_pattern(&opt, arg, "command line", 0,
 680                                             GREP_CLOSE_PAREN);
 681                         continue;
 682                 }
 683                 if (!strcmp("--all-match", arg)) {
 684                         opt.all_match = 1;
 685                         continue;
 686                 }
 687                 if (!strcmp("-e", arg)) {
 688                         if (1 < argc) {
 689                                 append_grep_pattern(&opt, argv[1],
 690                                                     "-e option", 0,
 691                                                     GREP_PATTERN);
 692                                 argv++;
 693                                 argc--;
 694                                 continue;
 695                         }
 696                         die(emsg_missing_argument, arg);
 697                 }
 698                 if (!strcmp("--full-name", arg)) {
 699                         opt.relative = 0;
 700                         continue;
 701                 }
 702                 if (!strcmp("--", arg)) {
 703                         /* later processing wants to have this at argv[1] */
 704                         argv--;
 705                         argc++;
 706                         break;
 707                 }
 708                 if (*arg == '-')
 709                         usage(builtin_grep_usage);
 710
 711                 /* First unrecognized non-option token */
 712                 if (!opt.pattern_list) {
 713                         append_grep_pattern(&opt, arg, "command line", 0,
 714                                             GREP_PATTERN);
 715                         break;
 716                 }
 717                 else {
 718                         /* We are looking at the first path or rev;
 719                          * it is found at argv[1] after leaving the
 720                          * loop.
 721                          */
 722                         argc++; argv--;
 723                         break;
 724                 }
 725         }
 726
 727         if (!opt.pattern_list)
 728                 die("no pattern given.");
 729         if ((opt.regflags != REG_NEWLINE) && opt.fixed)
 730                 die("cannot mix --fixed-strings and regexp");
 731         compile_grep_patterns(&opt);
 732
 733         /* Check revs and then paths */
 734         for (i = 1; i < argc; i++) {
 735                 const char *arg = argv[i];
 736                 unsigned char sha1[20];
 737                 /* Is it a rev? */
 738                 if (!get_sha1(arg, sha1)) {
 739                         struct object *object = parse_object(sha1);
 740                         if (!object)
 741                                 die("bad object %s", arg);
 742                         add_object_array(object, arg, &list);
 743                         continue;
 744                 }
 745                 if (!strcmp(arg, "--")) {
 746                         i++;
 747                         seen_dashdash = 1;
 748                 }
 749                 break;
 750         }
 751
 752         /* The rest are paths */
 753         if (!seen_dashdash) {
 754                 int j;
 755                 for (j = i; j < argc; j++)
 756                         verify_filename(prefix, argv[j]);
 757         }
 758
 759         if (i < argc) {
 760                 paths = get_pathspec(prefix, argv + i);
 761                 if (opt.prefix_length && opt.relative) {
 762                         /* Make sure we do not get outside of paths */
 763                         for (i = 0; paths[i]; i++)
 764                                 if (strncmp(prefix, paths[i], opt.prefix_length))
 765                                         die("git-grep: cannot generate relative filenames containing '..'");
 766                 }
 767         }
 768         else if (prefix) {
 769                 paths = xcalloc(2, sizeof(const char *));
 770                 paths[0] = prefix;
 771                 paths[1] = NULL;
 772         }
 773
 774         if (!list.nr)
 775                 return !grep_cache(&opt, paths, cached);
 776
 777         if (cached)
 778                 die("both --cached and trees are given.");
 779
 780         for (i = 0; i < list.nr; i++) {
 781                 struct object *real_obj;
 782                 real_obj = deref_tag(list.objects[i].item, NULL, 0);
 783                 if (grep_object(&opt, paths, real_obj, list.objects[i].name))
 784                         hit = 1;
 785         }
 786         free_grep_patterns(&opt);
 787         return !hit;
 788 }