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 #include "run-command.h"
  15
  16 #ifndef NO_EXTERNAL_GREP
  17 #ifdef __unix__
  18 #define NO_EXTERNAL_GREP 0
  19 #else
  20 #define NO_EXTERNAL_GREP 1
  21 #endif
  22 #endif
  23
  24 /*
  25  * git grep pathspecs are somewhat different from diff-tree pathspecs;
  26  * pathname wildcards are allowed.
  27  */
  28 static int pathspec_matches(const char **paths, const char *name)
  29 {
  30         int namelen, i;
  31         if (!paths || !*paths)
  32                 return 1;
  33         namelen = strlen(name);
  34         for (i = 0; paths[i]; i++) {
  35                 const char *match = paths[i];
  36                 int matchlen = strlen(match);
  37                 const char *cp, *meta;
  38
  39                 if (!matchlen ||
  40                     ((matchlen <= namelen) &&
  41                      !strncmp(name, match, matchlen) &&
  42                      (match[matchlen-1] == '/' ||
  43                       name[matchlen] == '\0' || name[matchlen] == '/')))
  44                         return 1;
  45                 if (!fnmatch(match, name, 0))
  46                         return 1;
  47                 if (name[namelen-1] != '/')
  48                         continue;
  49
  50                 /* We are being asked if the directory ("name") is worth
  51                  * descending into.
  52                  *
  53                  * Find the longest leading directory name that does
  54                  * not have metacharacter in the pathspec; the name
  55                  * we are looking at must overlap with that directory.
  56                  */
  57                 for (cp = match, meta = NULL; cp - match < matchlen; cp++) {
  58                         char ch = *cp;
  59                         if (ch == '*' || ch == '[' || ch == '?') {
  60                                 meta = cp;
  61                                 break;
  62                         }
  63                 }
  64                 if (!meta)
  65                         meta = cp; /* fully literal */
  66
  67                 if (namelen <= meta - match) {
  68                         /* Looking at "Documentation/" and
  69                          * the pattern says "Documentation/howto/", or
  70                          * "Documentation/diff*.txt".  The name we
  71                          * have should match prefix.
  72                          */
  73                         if (!memcmp(match, name, namelen))
  74                                 return 1;
  75                         continue;
  76                 }
  77
  78                 if (meta - match < namelen) {
  79                         /* Looking at "Documentation/howto/" and
  80                          * the pattern says "Documentation/h*";
  81                          * match up to "Do.../h"; this avoids descending
  82                          * into "Documentation/technical/".
  83                          */
  84                         if (!memcmp(match, name, meta - match))
  85                                 return 1;
  86                         continue;
  87                 }
  88         }
  89         return 0;
  90 }
  91
  92 static int grep_sha1(struct grep_opt *opt, const unsigned char *sha1, const char *name, int tree_name_len)
  93 {
  94         unsigned long size;
  95         char *data;
  96         enum object_type type;
  97         char *to_free = NULL;
  98         int hit;
  99
 100         data = read_sha1_file(sha1, &type, &size);
 101         if (!data) {
 102                 error("'%s': unable to read %s", name, sha1_to_hex(sha1));
 103                 return 0;
 104         }
 105         if (opt->relative && opt->prefix_length) {
 106                 static char name_buf[PATH_MAX];
 107                 char *cp;
 108                 int name_len = strlen(name) - opt->prefix_length + 1;
 109
 110                 if (!tree_name_len)
 111                         name += opt->prefix_length;
 112                 else {
 113                         if (ARRAY_SIZE(name_buf) <= name_len)
 114                                 cp = to_free = xmalloc(name_len);
 115                         else
 116                                 cp = name_buf;
 117                         memcpy(cp, name, tree_name_len);
 118                         strcpy(cp + tree_name_len,
 119                                name + tree_name_len + opt->prefix_length);
 120                         name = cp;
 121                 }
 122         }
 123         hit = grep_buffer(opt, name, data, size);
 124         free(data);
 125         free(to_free);
 126         return hit;
 127 }
 128
 129 static int grep_file(struct grep_opt *opt, const char *filename)
 130 {
 131         struct stat st;
 132         int i;
 133         char *data;
 134         size_t sz;
 135
 136         if (lstat(filename, &st) < 0) {
 137         err_ret:
 138                 if (errno != ENOENT)
 139                         error("'%s': %s", filename, strerror(errno));
 140                 return 0;
 141         }
 142         if (!st.st_size)
 143                 return 0; /* empty file -- no grep hit */
 144         if (!S_ISREG(st.st_mode))
 145                 return 0;
 146         sz = xsize_t(st.st_size);
 147         i = open(filename, O_RDONLY);
 148         if (i < 0)
 149                 goto err_ret;
 150         data = xmalloc(sz + 1);
 151         if (st.st_size != read_in_full(i, data, sz)) {
 152                 error("'%s': short read %s", filename, strerror(errno));
 153                 close(i);
 154                 free(data);
 155                 return 0;
 156         }
 157         close(i);
 158         if (opt->relative && opt->prefix_length)
 159                 filename += opt->prefix_length;
 160         i = grep_buffer(opt, filename, data, sz);
 161         free(data);
 162         return i;
 163 }
 164
 165 #if !NO_EXTERNAL_GREP
 166 #define MAXARGS 1000
 167 #define ARGBUF 4096
 168 #define push_arg(a) do { \
 169         if (nr < MAXARGS) argv[nr++] = (a); \
 170         else die("maximum number of args exceeded"); \
 171         } while (0)
 172
 173 /*
 174  * If you send a singleton filename to grep, it does not give
 175  * the name of the file.  GNU grep has "-H" but we would want
 176  * that behaviour in a portable way.
 177  *
 178  * So we keep two pathnames in argv buffer unsent to grep in
 179  * the main loop if we need to do more than one grep.
 180  */
 181 static int flush_grep(struct grep_opt *opt,
 182                       int argc, int arg0, const char **argv, int *kept)
 183 {
 184         int status;
 185         int count = argc - arg0;
 186         const char *kept_0 = NULL;
 187
 188         if (count <= 2) {
 189                 /*
 190                  * Because we keep at least 2 paths in the call from
 191                  * the main loop (i.e. kept != NULL), and MAXARGS is
 192                  * far greater than 2, this usually is a call to
 193                  * conclude the grep.  However, the user could attempt
 194                  * to overflow the argv buffer by giving too many
 195                  * options to leave very small number of real
 196                  * arguments even for the call in the main loop.
 197                  */
 198                 if (kept)
 199                         die("insanely many options to grep");
 200
 201                 /*
 202                  * If we have two or more paths, we do not have to do
 203                  * anything special, but we need to push /dev/null to
 204                  * get "-H" behaviour of GNU grep portably but when we
 205                  * are not doing "-l" nor "-L" nor "-c".
 206                  */
 207                 if (count == 1 &&
 208                     !opt->name_only &&
 209                     !opt->unmatch_name_only &&
 210                     !opt->count) {
 211                         argv[argc++] = "/dev/null";
 212                         argv[argc] = NULL;
 213                 }
 214         }
 215
 216         else if (kept) {
 217                 /*
 218                  * Called because we found many paths and haven't finished
 219                  * iterating over the cache yet.  We keep two paths
 220                  * for the concluding call.  argv[argc-2] and argv[argc-1]
 221                  * has the last two paths, so save the first one away,
 222                  * replace it with NULL while sending the list to grep,
 223                  * and recover them after we are done.
 224                  */
 225                 *kept = 2;
 226                 kept_0 = argv[argc-2];
 227                 argv[argc-2] = NULL;
 228                 argc -= 2;
 229         }
 230
 231         argv[argc] = NULL;
 232         status = run_command_v_opt(argv, 0);
 233
 234         if (kept_0) {
 235                 /*
 236                  * Then recover them.  Now the last arg is beyond the
 237                  * terminating NULL which is at argc, and the second
 238                  * from the last is what we saved away in kept_0
 239                  */
 240                 argv[arg0++] = kept_0;
 241                 argv[arg0] = argv[argc+1];
 242         }
 243         return status == 0 ? 1 : -1;
 244 }
 245
 246 static int external_grep(struct grep_opt *opt, const char **paths, int cached)
 247 {
 248         int i, nr, argc, hit, len, status;
 249         const char *argv[MAXARGS+1];
 250         char randarg[ARGBUF];
 251         char *argptr = randarg;
 252         struct grep_pat *p;
 253
 254         if (opt->extended || (opt->relative && opt->prefix_length))
 255                 return -1;
 256         len = nr = 0;
 257         push_arg("grep");
 258         if (opt->fixed)
 259                 push_arg("-F");
 260         if (opt->linenum)
 261                 push_arg("-n");
 262         if (!opt->pathname)
 263                 push_arg("-h");
 264         if (opt->regflags & REG_EXTENDED)
 265                 push_arg("-E");
 266         if (opt->regflags & REG_ICASE)
 267                 push_arg("-i");
 268         if (opt->word_regexp)
 269                 push_arg("-w");
 270         if (opt->name_only)
 271                 push_arg("-l");
 272         if (opt->unmatch_name_only)
 273                 push_arg("-L");
 274         if (opt->count)
 275                 push_arg("-c");
 276         if (opt->post_context || opt->pre_context) {
 277                 if (opt->post_context != opt->pre_context) {
 278                         if (opt->pre_context) {
 279                                 push_arg("-B");
 280                                 len += snprintf(argptr, sizeof(randarg)-len,
 281                                                 "%u", opt->pre_context) + 1;
 282                                 if (sizeof(randarg) <= len)
 283                                         die("maximum length of args exceeded");
 284                                 push_arg(argptr);
 285                                 argptr += len;
 286                         }
 287                         if (opt->post_context) {
 288                                 push_arg("-A");
 289                                 len += snprintf(argptr, sizeof(randarg)-len,
 290                                                 "%u", opt->post_context) + 1;
 291                                 if (sizeof(randarg) <= len)
 292                                         die("maximum length of args exceeded");
 293                                 push_arg(argptr);
 294                                 argptr += len;
 295                         }
 296                 }
 297                 else {
 298                         push_arg("-C");
 299                         len += snprintf(argptr, sizeof(randarg)-len,
 300                                         "%u", opt->post_context) + 1;
 301                         if (sizeof(randarg) <= len)
 302                                 die("maximum length of args exceeded");
 303                         push_arg(argptr);
 304                         argptr += len;
 305                 }
 306         }
 307         for (p = opt->pattern_list; p; p = p->next) {
 308                 push_arg("-e");
 309                 push_arg(p->pattern);
 310         }
 311
 312         hit = 0;
 313         argc = nr;
 314         for (i = 0; i < active_nr; i++) {
 315                 struct cache_entry *ce = active_cache[i];
 316                 char *name;
 317                 int kept;
 318                 if (!S_ISREG(ce->ce_mode))
 319                         continue;
 320                 if (!pathspec_matches(paths, ce->name))
 321                         continue;
 322                 name = ce->name;
 323                 if (name[0] == '-') {
 324                         int len = ce_namelen(ce);
 325                         name = xmalloc(len + 3);
 326                         memcpy(name, "./", 2);
 327                         memcpy(name + 2, ce->name, len + 1);
 328                 }
 329                 argv[argc++] = name;
 330                 if (MAXARGS <= argc) {
 331                         status = flush_grep(opt, argc, nr, argv, &kept);
 332                         if (0 < status)
 333                                 hit = 1;
 334                         argc = nr + kept;
 335                 }
 336                 if (ce_stage(ce)) {
 337                         do {
 338                                 i++;
 339                         } while (i < active_nr &&
 340                                  !strcmp(ce->name, active_cache[i]->name));
 341                         i--; /* compensate for loop control */
 342                 }
 343         }
 344         if (argc > nr) {
 345                 status = flush_grep(opt, argc, nr, argv, NULL);
 346                 if (0 < status)
 347                         hit = 1;
 348         }
 349         return hit;
 350 }
 351 #endif
 352
 353 static int grep_cache(struct grep_opt *opt, const char **paths, int cached)
 354 {
 355         int hit = 0;
 356         int nr;
 357         read_cache();
 358
 359 #if !NO_EXTERNAL_GREP
 360         /*
 361          * Use the external "grep" command for the case where
 362          * we grep through the checked-out files. It tends to
 363          * be a lot more optimized
 364          */
 365         if (!cached) {
 366                 hit = external_grep(opt, paths, cached);
 367                 if (hit >= 0)
 368                         return hit;
 369         }
 370 #endif
 371
 372         for (nr = 0; nr < active_nr; nr++) {
 373                 struct cache_entry *ce = active_cache[nr];
 374                 if (!S_ISREG(ce->ce_mode))
 375                         continue;
 376                 if (!pathspec_matches(paths, ce->name))
 377                         continue;
 378                 if (cached) {
 379                         if (ce_stage(ce))
 380                                 continue;
 381                         hit |= grep_sha1(opt, ce->sha1, ce->name, 0);
 382                 }
 383                 else
 384                         hit |= grep_file(opt, ce->name);
 385                 if (ce_stage(ce)) {
 386                         do {
 387                                 nr++;
 388                         } while (nr < active_nr &&
 389                                  !strcmp(ce->name, active_cache[nr]->name));
 390                         nr--; /* compensate for loop control */
 391                 }
 392         }
 393         free_grep_patterns(opt);
 394         return hit;
 395 }
 396
 397 static int grep_tree(struct grep_opt *opt, const char **paths,
 398                      struct tree_desc *tree,
 399                      const char *tree_name, const char *base)
 400 {
 401         int len;
 402         int hit = 0;
 403         struct name_entry entry;
 404         char *down;
 405         int tn_len = strlen(tree_name);
 406         char *path_buf = xmalloc(PATH_MAX + tn_len + 100);
 407
 408         if (tn_len) {
 409                 tn_len = sprintf(path_buf, "%s:", tree_name);
 410                 down = path_buf + tn_len;
 411                 strcat(down, base);
 412         }
 413         else {
 414                 down = path_buf;
 415                 strcpy(down, base);
 416         }
 417         len = strlen(path_buf);
 418
 419         while (tree_entry(tree, &entry)) {
 420                 strcpy(path_buf + len, entry.path);
 421
 422                 if (S_ISDIR(entry.mode))
 423                         /* Match "abc/" against pathspec to
 424                          * decide if we want to descend into "abc"
 425                          * directory.
 426                          */
 427                         strcpy(path_buf + len + tree_entry_len(entry.path, entry.sha1), "/");
 428
 429                 if (!pathspec_matches(paths, down))
 430                         ;
 431                 else if (S_ISREG(entry.mode))
 432                         hit |= grep_sha1(opt, entry.sha1, path_buf, tn_len);
 433                 else if (S_ISDIR(entry.mode)) {
 434                         enum object_type type;
 435                         struct tree_desc sub;
 436                         void *data;
 437                         unsigned long size;
 438
 439                         data = read_sha1_file(entry.sha1, &type, &size);
 440                         if (!data)
 441                                 die("unable to read tree (%s)",
 442                                     sha1_to_hex(entry.sha1));
 443                         init_tree_desc(&sub, data, size);
 444                         hit |= grep_tree(opt, paths, &sub, tree_name, down);
 445                         free(data);
 446                 }
 447         }
 448         return hit;
 449 }
 450
 451 static int grep_object(struct grep_opt *opt, const char **paths,
 452                        struct object *obj, const char *name)
 453 {
 454         if (obj->type == OBJ_BLOB)
 455                 return grep_sha1(opt, obj->sha1, name, 0);
 456         if (obj->type == OBJ_COMMIT || obj->type == OBJ_TREE) {
 457                 struct tree_desc tree;
 458                 void *data;
 459                 unsigned long size;
 460                 int hit;
 461                 data = read_object_with_reference(obj->sha1, tree_type,
 462                                                   &size, NULL);
 463                 if (!data)
 464                         die("unable to read tree (%s)", sha1_to_hex(obj->sha1));
 465                 init_tree_desc(&tree, data, size);
 466                 hit = grep_tree(opt, paths, &tree, name, "");
 467                 free(data);
 468                 return hit;
 469         }
 470         die("unable to grep from object of type %s", typename(obj->type));
 471 }
 472
 473 static const char builtin_grep_usage[] =
 474 "git-grep <option>* <rev>* [-e] <pattern> [<path>...]";
 475
 476 static const char emsg_invalid_context_len[] =
 477 "%s: invalid context length argument";
 478 static const char emsg_missing_context_len[] =
 479 "missing context length argument";
 480 static const char emsg_missing_argument[] =
 481 "option requires an argument -%s";
 482
 483 int cmd_grep(int argc, const char **argv, const char *prefix)
 484 {
 485         int hit = 0;
 486         int cached = 0;
 487         int seen_dashdash = 0;
 488         struct grep_opt opt;
 489         struct object_array list = { 0, 0, NULL };
 490         const char **paths = NULL;
 491         int i;
 492
 493         memset(&opt, 0, sizeof(opt));
 494         opt.prefix_length = (prefix && *prefix) ? strlen(prefix) : 0;
 495         opt.relative = 1;
 496         opt.pathname = 1;
 497         opt.pattern_tail = &opt.pattern_list;
 498         opt.regflags = REG_NEWLINE;
 499
 500         /*
 501          * If there is no -- then the paths must exist in the working
 502          * tree.  If there is no explicit pattern specified with -e or
 503          * -f, we take the first unrecognized non option to be the
 504          * pattern, but then what follows it must be zero or more
 505          * valid refs up to the -- (if exists), and then existing
 506          * paths.  If there is an explicit pattern, then the first
 507          * unrecognized non option is the beginning of the refs list
 508          * that continues up to the -- (if exists), and then paths.
 509          */
 510
 511         while (1 < argc) {
 512                 const char *arg = argv[1];
 513                 argc--; argv++;
 514                 if (!strcmp("--cached", arg)) {
 515                         cached = 1;
 516                         continue;
 517                 }
 518                 if (!strcmp("-a", arg) ||
 519                     !strcmp("--text", arg)) {
 520                         opt.binary = GREP_BINARY_TEXT;
 521                         continue;
 522                 }
 523                 if (!strcmp("-i", arg) ||
 524                     !strcmp("--ignore-case", arg)) {
 525                         opt.regflags |= REG_ICASE;
 526                         continue;
 527                 }
 528                 if (!strcmp("-I", arg)) {
 529                         opt.binary = GREP_BINARY_NOMATCH;
 530                         continue;
 531                 }
 532                 if (!strcmp("-v", arg) ||
 533                     !strcmp("--invert-match", arg)) {
 534                         opt.invert = 1;
 535                         continue;
 536                 }
 537                 if (!strcmp("-E", arg) ||
 538                     !strcmp("--extended-regexp", arg)) {
 539                         opt.regflags |= REG_EXTENDED;
 540                         continue;
 541                 }
 542                 if (!strcmp("-F", arg) ||
 543                     !strcmp("--fixed-strings", arg)) {
 544                         opt.fixed = 1;
 545                         continue;
 546                 }
 547                 if (!strcmp("-G", arg) ||
 548                     !strcmp("--basic-regexp", arg)) {
 549                         opt.regflags &= ~REG_EXTENDED;
 550                         continue;
 551                 }
 552                 if (!strcmp("-n", arg)) {
 553                         opt.linenum = 1;
 554                         continue;
 555                 }
 556                 if (!strcmp("-h", arg)) {
 557                         opt.pathname = 0;
 558                         continue;
 559                 }
 560                 if (!strcmp("-H", arg)) {
 561                         opt.pathname = 1;
 562                         continue;
 563                 }
 564                 if (!strcmp("-l", arg) ||
 565                     !strcmp("--name-only", arg) ||
 566                     !strcmp("--files-with-matches", arg)) {
 567                         opt.name_only = 1;
 568                         continue;
 569                 }
 570                 if (!strcmp("-L", arg) ||
 571                     !strcmp("--files-without-match", arg)) {
 572                         opt.unmatch_name_only = 1;
 573                         continue;
 574                 }
 575                 if (!strcmp("-c", arg) ||
 576                     !strcmp("--count", arg)) {
 577                         opt.count = 1;
 578                         continue;
 579                 }
 580                 if (!strcmp("-w", arg) ||
 581                     !strcmp("--word-regexp", arg)) {
 582                         opt.word_regexp = 1;
 583                         continue;
 584                 }
 585                 if (!prefixcmp(arg, "-A") ||
 586                     !prefixcmp(arg, "-B") ||
 587                     !prefixcmp(arg, "-C") ||
 588                     (arg[0] == '-' && '1' <= arg[1] && arg[1] <= '9')) {
 589                         unsigned num;
 590                         const char *scan;
 591                         switch (arg[1]) {
 592                         case 'A': case 'B': case 'C':
 593                                 if (!arg[2]) {
 594                                         if (argc <= 1)
 595                                                 die(emsg_missing_context_len);
 596                                         scan = *++argv;
 597                                         argc--;
 598                                 }
 599                                 else
 600                                         scan = arg + 2;
 601                                 break;
 602                         default:
 603                                 scan = arg + 1;
 604                                 break;
 605                         }
 606                         if (strtoul_ui(scan, 10, &num))
 607                                 die(emsg_invalid_context_len, scan);
 608                         switch (arg[1]) {
 609                         case 'A':
 610                                 opt.post_context = num;
 611                                 break;
 612                         default:
 613                         case 'C':
 614                                 opt.post_context = num;
 615                         case 'B':
 616                                 opt.pre_context = num;
 617                                 break;
 618                         }
 619                         continue;
 620                 }
 621                 if (!strcmp("-f", arg)) {
 622                         FILE *patterns;
 623                         int lno = 0;
 624                         char buf[1024];
 625                         if (argc <= 1)
 626                                 die(emsg_missing_argument, arg);
 627                         patterns = fopen(argv[1], "r");
 628                         if (!patterns)
 629                                 die("'%s': %s", argv[1], strerror(errno));
 630                         while (fgets(buf, sizeof(buf), patterns)) {
 631                                 int len = strlen(buf);
 632                                 if (len && buf[len-1] == '\n')
 633                                         buf[len-1] = 0;
 634                                 /* ignore empty line like grep does */
 635                                 if (!buf[0])
 636                                         continue;
 637                                 append_grep_pattern(&opt, xstrdup(buf),
 638                                                     argv[1], ++lno,
 639                                                     GREP_PATTERN);
 640                         }
 641                         fclose(patterns);
 642                         argv++;
 643                         argc--;
 644                         continue;
 645                 }
 646                 if (!strcmp("--not", arg)) {
 647                         append_grep_pattern(&opt, arg, "command line", 0,
 648                                             GREP_NOT);
 649                         continue;
 650                 }
 651                 if (!strcmp("--and", arg)) {
 652                         append_grep_pattern(&opt, arg, "command line", 0,
 653                                             GREP_AND);
 654                         continue;
 655                 }
 656                 if (!strcmp("--or", arg))
 657                         continue; /* no-op */
 658                 if (!strcmp("(", arg)) {
 659                         append_grep_pattern(&opt, arg, "command line", 0,
 660                                             GREP_OPEN_PAREN);
 661                         continue;
 662                 }
 663                 if (!strcmp(")", arg)) {
 664                         append_grep_pattern(&opt, arg, "command line", 0,
 665                                             GREP_CLOSE_PAREN);
 666                         continue;
 667                 }
 668                 if (!strcmp("--all-match", arg)) {
 669                         opt.all_match = 1;
 670                         continue;
 671                 }
 672                 if (!strcmp("-e", arg)) {
 673                         if (1 < argc) {
 674                                 append_grep_pattern(&opt, argv[1],
 675                                                     "-e option", 0,
 676                                                     GREP_PATTERN);
 677                                 argv++;
 678                                 argc--;
 679                                 continue;
 680                         }
 681                         die(emsg_missing_argument, arg);
 682                 }
 683                 if (!strcmp("--full-name", arg)) {
 684                         opt.relative = 0;
 685                         continue;
 686                 }
 687                 if (!strcmp("--", arg)) {
 688                         /* later processing wants to have this at argv[1] */
 689                         argv--;
 690                         argc++;
 691                         break;
 692                 }
 693                 if (*arg == '-')
 694                         usage(builtin_grep_usage);
 695
 696                 /* First unrecognized non-option token */
 697                 if (!opt.pattern_list) {
 698                         append_grep_pattern(&opt, arg, "command line", 0,
 699                                             GREP_PATTERN);
 700                         break;
 701                 }
 702                 else {
 703                         /* We are looking at the first path or rev;
 704                          * it is found at argv[1] after leaving the
 705                          * loop.
 706                          */
 707                         argc++; argv--;
 708                         break;
 709                 }
 710         }
 711
 712         if (!opt.pattern_list)
 713                 die("no pattern given.");
 714         if ((opt.regflags != REG_NEWLINE) && opt.fixed)
 715                 die("cannot mix --fixed-strings and regexp");
 716         compile_grep_patterns(&opt);
 717
 718         /* Check revs and then paths */
 719         for (i = 1; i < argc; i++) {
 720                 const char *arg = argv[i];
 721                 unsigned char sha1[20];
 722                 /* Is it a rev? */
 723                 if (!get_sha1(arg, sha1)) {
 724                         struct object *object = parse_object(sha1);
 725                         if (!object)
 726                                 die("bad object %s", arg);
 727                         add_object_array(object, arg, &list);
 728                         continue;
 729                 }
 730                 if (!strcmp(arg, "--")) {
 731                         i++;
 732                         seen_dashdash = 1;
 733                 }
 734                 break;
 735         }
 736
 737         /* The rest are paths */
 738         if (!seen_dashdash) {
 739                 int j;
 740                 for (j = i; j < argc; j++)
 741                         verify_filename(prefix, argv[j]);
 742         }
 743
 744         if (i < argc) {
 745                 paths = get_pathspec(prefix, argv + i);
 746                 if (opt.prefix_length && opt.relative) {
 747                         /* Make sure we do not get outside of paths */
 748                         for (i = 0; paths[i]; i++)
 749                                 if (strncmp(prefix, paths[i], opt.prefix_length))
 750                                         die("git-grep: cannot generate relative filenames containing '..'");
 751                 }
 752         }
 753         else if (prefix) {
 754                 paths = xcalloc(2, sizeof(const char *));
 755                 paths[0] = prefix;
 756                 paths[1] = NULL;
 757         }
 758
 759         if (!list.nr)
 760                 return !grep_cache(&opt, paths, cached);
 761
 762         if (cached)
 763                 die("both --cached and trees are given.");
 764
 765         for (i = 0; i < list.nr; i++) {
 766                 struct object *real_obj;
 767                 real_obj = deref_tag(list.objects[i].item, NULL, 0);
 768                 if (grep_object(&opt, paths, real_obj, list.objects[i].name))
 769                         hit = 1;
 770         }
 771         free_grep_patterns(&opt);
 772         return !hit;
 773 }