builtin-grep.con commit Teach git mergetool to use custom commands defined at config time (964473a)
   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 */
  19static 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
  83static 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
 120static 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__
 157static 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 */
 198static 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
 262static 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(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
 369static 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(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
 413static 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
 467static 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
 489static const char builtin_grep_usage[] =
 490"git-grep <option>* <rev>* [-e] <pattern> [<path>...]";
 491
 492static const char emsg_invalid_context_len[] =
 493"%s: invalid context length argument";
 494static const char emsg_missing_context_len[] =
 495"missing context length argument";
 496static const char emsg_missing_argument[] =
 497"option requires an argument -%s";
 498
 499int 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("--name-only", arg) ||
 582                    !strcmp("--files-with-matches", arg)) {
 583                        opt.name_only = 1;
 584                        continue;
 585                }
 586                if (!strcmp("-L", arg) ||
 587                    !strcmp("--files-without-match", arg)) {
 588                        opt.unmatch_name_only = 1;
 589                        continue;
 590                }
 591                if (!strcmp("-c", arg) ||
 592                    !strcmp("--count", arg)) {
 593                        opt.count = 1;
 594                        continue;
 595                }
 596                if (!strcmp("-w", arg) ||
 597                    !strcmp("--word-regexp", arg)) {
 598                        opt.word_regexp = 1;
 599                        continue;
 600                }
 601                if (!prefixcmp(arg, "-A") ||
 602                    !prefixcmp(arg, "-B") ||
 603                    !prefixcmp(arg, "-C") ||
 604                    (arg[0] == '-' && '1' <= arg[1] && arg[1] <= '9')) {
 605                        unsigned num;
 606                        const char *scan;
 607                        switch (arg[1]) {
 608                        case 'A': case 'B': case 'C':
 609                                if (!arg[2]) {
 610                                        if (argc <= 1)
 611                                                die(emsg_missing_context_len);
 612                                        scan = *++argv;
 613                                        argc--;
 614                                }
 615                                else
 616                                        scan = arg + 2;
 617                                break;
 618                        default:
 619                                scan = arg + 1;
 620                                break;
 621                        }
 622                        if (strtoul_ui(scan, 10, &num))
 623                                die(emsg_invalid_context_len, scan);
 624                        switch (arg[1]) {
 625                        case 'A':
 626                                opt.post_context = num;
 627                                break;
 628                        default:
 629                        case 'C':
 630                                opt.post_context = num;
 631                        case 'B':
 632                                opt.pre_context = num;
 633                                break;
 634                        }
 635                        continue;
 636                }
 637                if (!strcmp("-f", arg)) {
 638                        FILE *patterns;
 639                        int lno = 0;
 640                        char buf[1024];
 641                        if (argc <= 1)
 642                                die(emsg_missing_argument, arg);
 643                        patterns = fopen(argv[1], "r");
 644                        if (!patterns)
 645                                die("'%s': %s", argv[1], strerror(errno));
 646                        while (fgets(buf, sizeof(buf), patterns)) {
 647                                int len = strlen(buf);
 648                                if (len && buf[len-1] == '\n')
 649                                        buf[len-1] = 0;
 650                                /* ignore empty line like grep does */
 651                                if (!buf[0])
 652                                        continue;
 653                                append_grep_pattern(&opt, xstrdup(buf),
 654                                                    argv[1], ++lno,
 655                                                    GREP_PATTERN);
 656                        }
 657                        fclose(patterns);
 658                        argv++;
 659                        argc--;
 660                        continue;
 661                }
 662                if (!strcmp("--not", arg)) {
 663                        append_grep_pattern(&opt, arg, "command line", 0,
 664                                            GREP_NOT);
 665                        continue;
 666                }
 667                if (!strcmp("--and", arg)) {
 668                        append_grep_pattern(&opt, arg, "command line", 0,
 669                                            GREP_AND);
 670                        continue;
 671                }
 672                if (!strcmp("--or", arg))
 673                        continue; /* no-op */
 674                if (!strcmp("(", arg)) {
 675                        append_grep_pattern(&opt, arg, "command line", 0,
 676                                            GREP_OPEN_PAREN);
 677                        continue;
 678                }
 679                if (!strcmp(")", arg)) {
 680                        append_grep_pattern(&opt, arg, "command line", 0,
 681                                            GREP_CLOSE_PAREN);
 682                        continue;
 683                }
 684                if (!strcmp("--all-match", arg)) {
 685                        opt.all_match = 1;
 686                        continue;
 687                }
 688                if (!strcmp("-e", arg)) {
 689                        if (1 < argc) {
 690                                append_grep_pattern(&opt, argv[1],
 691                                                    "-e option", 0,
 692                                                    GREP_PATTERN);
 693                                argv++;
 694                                argc--;
 695                                continue;
 696                        }
 697                        die(emsg_missing_argument, arg);
 698                }
 699                if (!strcmp("--full-name", arg)) {
 700                        opt.relative = 0;
 701                        continue;
 702                }
 703                if (!strcmp("--", arg)) {
 704                        /* later processing wants to have this at argv[1] */
 705                        argv--;
 706                        argc++;
 707                        break;
 708                }
 709                if (*arg == '-')
 710                        usage(builtin_grep_usage);
 711
 712                /* First unrecognized non-option token */
 713                if (!opt.pattern_list) {
 714                        append_grep_pattern(&opt, arg, "command line", 0,
 715                                            GREP_PATTERN);
 716                        break;
 717                }
 718                else {
 719                        /* We are looking at the first path or rev;
 720                         * it is found at argv[1] after leaving the
 721                         * loop.
 722                         */
 723                        argc++; argv--;
 724                        break;
 725                }
 726        }
 727
 728        if (!opt.pattern_list)
 729                die("no pattern given.");
 730        if ((opt.regflags != REG_NEWLINE) && opt.fixed)
 731                die("cannot mix --fixed-strings and regexp");
 732        compile_grep_patterns(&opt);
 733
 734        /* Check revs and then paths */
 735        for (i = 1; i < argc; i++) {
 736                const char *arg = argv[i];
 737                unsigned char sha1[20];
 738                /* Is it a rev? */
 739                if (!get_sha1(arg, sha1)) {
 740                        struct object *object = parse_object(sha1);
 741                        if (!object)
 742                                die("bad object %s", arg);
 743                        add_object_array(object, arg, &list);
 744                        continue;
 745                }
 746                if (!strcmp(arg, "--")) {
 747                        i++;
 748                        seen_dashdash = 1;
 749                }
 750                break;
 751        }
 752
 753        /* The rest are paths */
 754        if (!seen_dashdash) {
 755                int j;
 756                for (j = i; j < argc; j++)
 757                        verify_filename(prefix, argv[j]);
 758        }
 759
 760        if (i < argc) {
 761                paths = get_pathspec(prefix, argv + i);
 762                if (opt.prefix_length && opt.relative) {
 763                        /* Make sure we do not get outside of paths */
 764                        for (i = 0; paths[i]; i++)
 765                                if (strncmp(prefix, paths[i], opt.prefix_length))
 766                                        die("git-grep: cannot generate relative filenames containing '..'");
 767                }
 768        }
 769        else if (prefix) {
 770                paths = xcalloc(2, sizeof(const char *));
 771                paths[0] = prefix;
 772                paths[1] = NULL;
 773        }
 774
 775        if (!list.nr)
 776                return !grep_cache(&opt, paths, cached);
 777
 778        if (cached)
 779                die("both --cached and trees are given.");
 780
 781        for (i = 0; i < list.nr; i++) {
 782                struct object *real_obj;
 783                real_obj = deref_tag(list.objects[i].item, NULL, 0);
 784                if (grep_object(&opt, paths, real_obj, list.objects[i].name))
 785                        hit = 1;
 786        }
 787        free_grep_patterns(&opt);
 788        return !hit;
 789}