builtin-grep.con commit filter-branch: add git_commit_non_empty_tree and --prune-empty. (d3240d9)
   1/*
   2 * Builtin "git grep"
   3 *
   4 * Copyright (c) 2006 Junio C Hamano
   5 */
   6#include "cache.h"
   7#include "blob.h"
   8#include "tree.h"
   9#include "commit.h"
  10#include "tag.h"
  11#include "tree-walk.h"
  12#include "builtin.h"
  13#include "grep.h"
  14
  15#ifndef NO_EXTERNAL_GREP
  16#ifdef __unix__
  17#define NO_EXTERNAL_GREP 0
  18#else
  19#define NO_EXTERNAL_GREP 1
  20#endif
  21#endif
  22
  23/*
  24 * git grep pathspecs are somewhat different from diff-tree pathspecs;
  25 * pathname wildcards are allowed.
  26 */
  27static int pathspec_matches(const char **paths, const char *name)
  28{
  29        int namelen, i;
  30        if (!paths || !*paths)
  31                return 1;
  32        namelen = strlen(name);
  33        for (i = 0; paths[i]; i++) {
  34                const char *match = paths[i];
  35                int matchlen = strlen(match);
  36                const char *cp, *meta;
  37
  38                if (!matchlen ||
  39                    ((matchlen <= namelen) &&
  40                     !strncmp(name, match, matchlen) &&
  41                     (match[matchlen-1] == '/' ||
  42                      name[matchlen] == '\0' || name[matchlen] == '/')))
  43                        return 1;
  44                if (!fnmatch(match, name, 0))
  45                        return 1;
  46                if (name[namelen-1] != '/')
  47                        continue;
  48
  49                /* We are being asked if the directory ("name") is worth
  50                 * descending into.
  51                 *
  52                 * Find the longest leading directory name that does
  53                 * not have metacharacter in the pathspec; the name
  54                 * we are looking at must overlap with that directory.
  55                 */
  56                for (cp = match, meta = NULL; cp - match < matchlen; cp++) {
  57                        char ch = *cp;
  58                        if (ch == '*' || ch == '[' || ch == '?') {
  59                                meta = cp;
  60                                break;
  61                        }
  62                }
  63                if (!meta)
  64                        meta = cp; /* fully literal */
  65
  66                if (namelen <= meta - match) {
  67                        /* Looking at "Documentation/" and
  68                         * the pattern says "Documentation/howto/", or
  69                         * "Documentation/diff*.txt".  The name we
  70                         * have should match prefix.
  71                         */
  72                        if (!memcmp(match, name, namelen))
  73                                return 1;
  74                        continue;
  75                }
  76
  77                if (meta - match < namelen) {
  78                        /* Looking at "Documentation/howto/" and
  79                         * the pattern says "Documentation/h*";
  80                         * match up to "Do.../h"; this avoids descending
  81                         * into "Documentation/technical/".
  82                         */
  83                        if (!memcmp(match, name, meta - match))
  84                                return 1;
  85                        continue;
  86                }
  87        }
  88        return 0;
  89}
  90
  91static int grep_sha1(struct grep_opt *opt, const unsigned char *sha1, const char *name, int tree_name_len)
  92{
  93        unsigned long size;
  94        char *data;
  95        enum object_type type;
  96        char *to_free = NULL;
  97        int hit;
  98
  99        data = read_sha1_file(sha1, &type, &size);
 100        if (!data) {
 101                error("'%s': unable to read %s", name, sha1_to_hex(sha1));
 102                return 0;
 103        }
 104        if (opt->relative && opt->prefix_length) {
 105                static char name_buf[PATH_MAX];
 106                char *cp;
 107                int name_len = strlen(name) - opt->prefix_length + 1;
 108
 109                if (!tree_name_len)
 110                        name += opt->prefix_length;
 111                else {
 112                        if (ARRAY_SIZE(name_buf) <= name_len)
 113                                cp = to_free = xmalloc(name_len);
 114                        else
 115                                cp = name_buf;
 116                        memcpy(cp, name, tree_name_len);
 117                        strcpy(cp + tree_name_len,
 118                               name + tree_name_len + opt->prefix_length);
 119                        name = cp;
 120                }
 121        }
 122        hit = grep_buffer(opt, name, data, size);
 123        free(data);
 124        free(to_free);
 125        return hit;
 126}
 127
 128static int grep_file(struct grep_opt *opt, const char *filename)
 129{
 130        struct stat st;
 131        int i;
 132        char *data;
 133        size_t sz;
 134
 135        if (lstat(filename, &st) < 0) {
 136        err_ret:
 137                if (errno != ENOENT)
 138                        error("'%s': %s", filename, strerror(errno));
 139                return 0;
 140        }
 141        if (!st.st_size)
 142                return 0; /* empty file -- no grep hit */
 143        if (!S_ISREG(st.st_mode))
 144                return 0;
 145        sz = xsize_t(st.st_size);
 146        i = open(filename, O_RDONLY);
 147        if (i < 0)
 148                goto err_ret;
 149        data = xmalloc(sz + 1);
 150        if (st.st_size != read_in_full(i, data, sz)) {
 151                error("'%s': short read %s", filename, strerror(errno));
 152                close(i);
 153                free(data);
 154                return 0;
 155        }
 156        close(i);
 157        if (opt->relative && opt->prefix_length)
 158                filename += opt->prefix_length;
 159        i = grep_buffer(opt, filename, data, sz);
 160        free(data);
 161        return i;
 162}
 163
 164#if !NO_EXTERNAL_GREP
 165static int exec_grep(int argc, const char **argv)
 166{
 167        pid_t pid;
 168        int status;
 169
 170        argv[argc] = NULL;
 171        pid = fork();
 172        if (pid < 0)
 173                return pid;
 174        if (!pid) {
 175                execvp("grep", (char **) argv);
 176                exit(255);
 177        }
 178        while (waitpid(pid, &status, 0) < 0) {
 179                if (errno == EINTR)
 180                        continue;
 181                return -1;
 182        }
 183        if (WIFEXITED(status)) {
 184                if (!WEXITSTATUS(status))
 185                        return 1;
 186                return 0;
 187        }
 188        return -1;
 189}
 190
 191#define MAXARGS 1000
 192#define ARGBUF 4096
 193#define push_arg(a) do { \
 194        if (nr < MAXARGS) argv[nr++] = (a); \
 195        else die("maximum number of args exceeded"); \
 196        } while (0)
 197
 198/*
 199 * If you send a singleton filename to grep, it does not give
 200 * the name of the file.  GNU grep has "-H" but we would want
 201 * that behaviour in a portable way.
 202 *
 203 * So we keep two pathnames in argv buffer unsent to grep in
 204 * the main loop if we need to do more than one grep.
 205 */
 206static int flush_grep(struct grep_opt *opt,
 207                      int argc, int arg0, const char **argv, int *kept)
 208{
 209        int status;
 210        int count = argc - arg0;
 211        const char *kept_0 = NULL;
 212
 213        if (count <= 2) {
 214                /*
 215                 * Because we keep at least 2 paths in the call from
 216                 * the main loop (i.e. kept != NULL), and MAXARGS is
 217                 * far greater than 2, this usually is a call to
 218                 * conclude the grep.  However, the user could attempt
 219                 * to overflow the argv buffer by giving too many
 220                 * options to leave very small number of real
 221                 * arguments even for the call in the main loop.
 222                 */
 223                if (kept)
 224                        die("insanely many options to grep");
 225
 226                /*
 227                 * If we have two or more paths, we do not have to do
 228                 * anything special, but we need to push /dev/null to
 229                 * get "-H" behaviour of GNU grep portably but when we
 230                 * are not doing "-l" nor "-L" nor "-c".
 231                 */
 232                if (count == 1 &&
 233                    !opt->name_only &&
 234                    !opt->unmatch_name_only &&
 235                    !opt->count) {
 236                        argv[argc++] = "/dev/null";
 237                        argv[argc] = NULL;
 238                }
 239        }
 240
 241        else if (kept) {
 242                /*
 243                 * Called because we found many paths and haven't finished
 244                 * iterating over the cache yet.  We keep two paths
 245                 * for the concluding call.  argv[argc-2] and argv[argc-1]
 246                 * has the last two paths, so save the first one away,
 247                 * replace it with NULL while sending the list to grep,
 248                 * and recover them after we are done.
 249                 */
 250                *kept = 2;
 251                kept_0 = argv[argc-2];
 252                argv[argc-2] = NULL;
 253                argc -= 2;
 254        }
 255
 256        status = exec_grep(argc, argv);
 257
 258        if (kept_0) {
 259                /*
 260                 * Then recover them.  Now the last arg is beyond the
 261                 * terminating NULL which is at argc, and the second
 262                 * from the last is what we saved away in kept_0
 263                 */
 264                argv[arg0++] = kept_0;
 265                argv[arg0] = argv[argc+1];
 266        }
 267        return status;
 268}
 269
 270static int external_grep(struct grep_opt *opt, const char **paths, int cached)
 271{
 272        int i, nr, argc, hit, len, status;
 273        const char *argv[MAXARGS+1];
 274        char randarg[ARGBUF];
 275        char *argptr = randarg;
 276        struct grep_pat *p;
 277
 278        if (opt->extended || (opt->relative && opt->prefix_length))
 279                return -1;
 280        len = nr = 0;
 281        push_arg("grep");
 282        if (opt->fixed)
 283                push_arg("-F");
 284        if (opt->linenum)
 285                push_arg("-n");
 286        if (!opt->pathname)
 287                push_arg("-h");
 288        if (opt->regflags & REG_EXTENDED)
 289                push_arg("-E");
 290        if (opt->regflags & REG_ICASE)
 291                push_arg("-i");
 292        if (opt->word_regexp)
 293                push_arg("-w");
 294        if (opt->name_only)
 295                push_arg("-l");
 296        if (opt->unmatch_name_only)
 297                push_arg("-L");
 298        if (opt->null_following_name)
 299                /* in GNU grep git's "-z" translates to "-Z" */
 300                push_arg("-Z");
 301        if (opt->count)
 302                push_arg("-c");
 303        if (opt->post_context || opt->pre_context) {
 304                if (opt->post_context != opt->pre_context) {
 305                        if (opt->pre_context) {
 306                                push_arg("-B");
 307                                len += snprintf(argptr, sizeof(randarg)-len,
 308                                                "%u", opt->pre_context) + 1;
 309                                if (sizeof(randarg) <= len)
 310                                        die("maximum length of args exceeded");
 311                                push_arg(argptr);
 312                                argptr += len;
 313                        }
 314                        if (opt->post_context) {
 315                                push_arg("-A");
 316                                len += snprintf(argptr, sizeof(randarg)-len,
 317                                                "%u", opt->post_context) + 1;
 318                                if (sizeof(randarg) <= len)
 319                                        die("maximum length of args exceeded");
 320                                push_arg(argptr);
 321                                argptr += len;
 322                        }
 323                }
 324                else {
 325                        push_arg("-C");
 326                        len += snprintf(argptr, sizeof(randarg)-len,
 327                                        "%u", opt->post_context) + 1;
 328                        if (sizeof(randarg) <= len)
 329                                die("maximum length of args exceeded");
 330                        push_arg(argptr);
 331                        argptr += len;
 332                }
 333        }
 334        for (p = opt->pattern_list; p; p = p->next) {
 335                push_arg("-e");
 336                push_arg(p->pattern);
 337        }
 338
 339        hit = 0;
 340        argc = nr;
 341        for (i = 0; i < active_nr; i++) {
 342                struct cache_entry *ce = active_cache[i];
 343                char *name;
 344                int kept;
 345                if (!S_ISREG(ce->ce_mode))
 346                        continue;
 347                if (!pathspec_matches(paths, ce->name))
 348                        continue;
 349                name = ce->name;
 350                if (name[0] == '-') {
 351                        int len = ce_namelen(ce);
 352                        name = xmalloc(len + 3);
 353                        memcpy(name, "./", 2);
 354                        memcpy(name + 2, ce->name, len + 1);
 355                }
 356                argv[argc++] = name;
 357                if (MAXARGS <= argc) {
 358                        status = flush_grep(opt, argc, nr, argv, &kept);
 359                        if (0 < status)
 360                                hit = 1;
 361                        argc = nr + kept;
 362                }
 363                if (ce_stage(ce)) {
 364                        do {
 365                                i++;
 366                        } while (i < active_nr &&
 367                                 !strcmp(ce->name, active_cache[i]->name));
 368                        i--; /* compensate for loop control */
 369                }
 370        }
 371        if (argc > nr) {
 372                status = flush_grep(opt, argc, nr, argv, NULL);
 373                if (0 < status)
 374                        hit = 1;
 375        }
 376        return hit;
 377}
 378#endif
 379
 380static int grep_cache(struct grep_opt *opt, const char **paths, int cached)
 381{
 382        int hit = 0;
 383        int nr;
 384        read_cache();
 385
 386#if !NO_EXTERNAL_GREP
 387        /*
 388         * Use the external "grep" command for the case where
 389         * we grep through the checked-out files. It tends to
 390         * be a lot more optimized
 391         */
 392        if (!cached) {
 393                hit = external_grep(opt, paths, cached);
 394                if (hit >= 0)
 395                        return hit;
 396        }
 397#endif
 398
 399        for (nr = 0; nr < active_nr; nr++) {
 400                struct cache_entry *ce = active_cache[nr];
 401                if (!S_ISREG(ce->ce_mode))
 402                        continue;
 403                if (!pathspec_matches(paths, ce->name))
 404                        continue;
 405                if (cached) {
 406                        if (ce_stage(ce))
 407                                continue;
 408                        hit |= grep_sha1(opt, ce->sha1, ce->name, 0);
 409                }
 410                else
 411                        hit |= grep_file(opt, ce->name);
 412                if (ce_stage(ce)) {
 413                        do {
 414                                nr++;
 415                        } while (nr < active_nr &&
 416                                 !strcmp(ce->name, active_cache[nr]->name));
 417                        nr--; /* compensate for loop control */
 418                }
 419        }
 420        free_grep_patterns(opt);
 421        return hit;
 422}
 423
 424static int grep_tree(struct grep_opt *opt, const char **paths,
 425                     struct tree_desc *tree,
 426                     const char *tree_name, const char *base)
 427{
 428        int len;
 429        int hit = 0;
 430        struct name_entry entry;
 431        char *down;
 432        int tn_len = strlen(tree_name);
 433        struct strbuf pathbuf;
 434
 435        strbuf_init(&pathbuf, PATH_MAX + tn_len);
 436
 437        if (tn_len) {
 438                strbuf_add(&pathbuf, tree_name, tn_len);
 439                strbuf_addch(&pathbuf, ':');
 440                tn_len = pathbuf.len;
 441        }
 442        strbuf_addstr(&pathbuf, base);
 443        len = pathbuf.len;
 444
 445        while (tree_entry(tree, &entry)) {
 446                int te_len = tree_entry_len(entry.path, entry.sha1);
 447                pathbuf.len = len;
 448                strbuf_add(&pathbuf, entry.path, te_len);
 449
 450                if (S_ISDIR(entry.mode))
 451                        /* Match "abc/" against pathspec to
 452                         * decide if we want to descend into "abc"
 453                         * directory.
 454                         */
 455                        strbuf_addch(&pathbuf, '/');
 456
 457                down = pathbuf.buf + tn_len;
 458                if (!pathspec_matches(paths, down))
 459                        ;
 460                else if (S_ISREG(entry.mode))
 461                        hit |= grep_sha1(opt, entry.sha1, pathbuf.buf, tn_len);
 462                else if (S_ISDIR(entry.mode)) {
 463                        enum object_type type;
 464                        struct tree_desc sub;
 465                        void *data;
 466                        unsigned long size;
 467
 468                        data = read_sha1_file(entry.sha1, &type, &size);
 469                        if (!data)
 470                                die("unable to read tree (%s)",
 471                                    sha1_to_hex(entry.sha1));
 472                        init_tree_desc(&sub, data, size);
 473                        hit |= grep_tree(opt, paths, &sub, tree_name, down);
 474                        free(data);
 475                }
 476        }
 477        strbuf_release(&pathbuf);
 478        return hit;
 479}
 480
 481static int grep_object(struct grep_opt *opt, const char **paths,
 482                       struct object *obj, const char *name)
 483{
 484        if (obj->type == OBJ_BLOB)
 485                return grep_sha1(opt, obj->sha1, name, 0);
 486        if (obj->type == OBJ_COMMIT || obj->type == OBJ_TREE) {
 487                struct tree_desc tree;
 488                void *data;
 489                unsigned long size;
 490                int hit;
 491                data = read_object_with_reference(obj->sha1, tree_type,
 492                                                  &size, NULL);
 493                if (!data)
 494                        die("unable to read tree (%s)", sha1_to_hex(obj->sha1));
 495                init_tree_desc(&tree, data, size);
 496                hit = grep_tree(opt, paths, &tree, name, "");
 497                free(data);
 498                return hit;
 499        }
 500        die("unable to grep from object of type %s", typename(obj->type));
 501}
 502
 503static const char builtin_grep_usage[] =
 504"git grep <option>* [-e] <pattern> <rev>* [[--] <path>...]";
 505
 506static const char emsg_invalid_context_len[] =
 507"%s: invalid context length argument";
 508static const char emsg_missing_context_len[] =
 509"missing context length argument";
 510static const char emsg_missing_argument[] =
 511"option requires an argument -%s";
 512
 513int cmd_grep(int argc, const char **argv, const char *prefix)
 514{
 515        int hit = 0;
 516        int cached = 0;
 517        int seen_dashdash = 0;
 518        struct grep_opt opt;
 519        struct object_array list = { 0, 0, NULL };
 520        const char **paths = NULL;
 521        int i;
 522
 523        memset(&opt, 0, sizeof(opt));
 524        opt.prefix_length = (prefix && *prefix) ? strlen(prefix) : 0;
 525        opt.relative = 1;
 526        opt.pathname = 1;
 527        opt.pattern_tail = &opt.pattern_list;
 528        opt.regflags = REG_NEWLINE;
 529
 530        /*
 531         * If there is no -- then the paths must exist in the working
 532         * tree.  If there is no explicit pattern specified with -e or
 533         * -f, we take the first unrecognized non option to be the
 534         * pattern, but then what follows it must be zero or more
 535         * valid refs up to the -- (if exists), and then existing
 536         * paths.  If there is an explicit pattern, then the first
 537         * unrecognized non option is the beginning of the refs list
 538         * that continues up to the -- (if exists), and then paths.
 539         */
 540
 541        while (1 < argc) {
 542                const char *arg = argv[1];
 543                argc--; argv++;
 544                if (!strcmp("--cached", arg)) {
 545                        cached = 1;
 546                        continue;
 547                }
 548                if (!strcmp("-a", arg) ||
 549                    !strcmp("--text", arg)) {
 550                        opt.binary = GREP_BINARY_TEXT;
 551                        continue;
 552                }
 553                if (!strcmp("-i", arg) ||
 554                    !strcmp("--ignore-case", arg)) {
 555                        opt.regflags |= REG_ICASE;
 556                        continue;
 557                }
 558                if (!strcmp("-I", arg)) {
 559                        opt.binary = GREP_BINARY_NOMATCH;
 560                        continue;
 561                }
 562                if (!strcmp("-v", arg) ||
 563                    !strcmp("--invert-match", arg)) {
 564                        opt.invert = 1;
 565                        continue;
 566                }
 567                if (!strcmp("-E", arg) ||
 568                    !strcmp("--extended-regexp", arg)) {
 569                        opt.regflags |= REG_EXTENDED;
 570                        continue;
 571                }
 572                if (!strcmp("-F", arg) ||
 573                    !strcmp("--fixed-strings", arg)) {
 574                        opt.fixed = 1;
 575                        continue;
 576                }
 577                if (!strcmp("-G", arg) ||
 578                    !strcmp("--basic-regexp", arg)) {
 579                        opt.regflags &= ~REG_EXTENDED;
 580                        continue;
 581                }
 582                if (!strcmp("-n", arg)) {
 583                        opt.linenum = 1;
 584                        continue;
 585                }
 586                if (!strcmp("-h", arg)) {
 587                        opt.pathname = 0;
 588                        continue;
 589                }
 590                if (!strcmp("-H", arg)) {
 591                        opt.pathname = 1;
 592                        continue;
 593                }
 594                if (!strcmp("-l", arg) ||
 595                    !strcmp("--name-only", arg) ||
 596                    !strcmp("--files-with-matches", arg)) {
 597                        opt.name_only = 1;
 598                        continue;
 599                }
 600                if (!strcmp("-L", arg) ||
 601                    !strcmp("--files-without-match", arg)) {
 602                        opt.unmatch_name_only = 1;
 603                        continue;
 604                }
 605                if (!strcmp("-z", arg) ||
 606                    !strcmp("--null", arg)) {
 607                        opt.null_following_name = 1;
 608                        continue;
 609                }
 610                if (!strcmp("-c", arg) ||
 611                    !strcmp("--count", arg)) {
 612                        opt.count = 1;
 613                        continue;
 614                }
 615                if (!strcmp("-w", arg) ||
 616                    !strcmp("--word-regexp", arg)) {
 617                        opt.word_regexp = 1;
 618                        continue;
 619                }
 620                if (!prefixcmp(arg, "-A") ||
 621                    !prefixcmp(arg, "-B") ||
 622                    !prefixcmp(arg, "-C") ||
 623                    (arg[0] == '-' && '1' <= arg[1] && arg[1] <= '9')) {
 624                        unsigned num;
 625                        const char *scan;
 626                        switch (arg[1]) {
 627                        case 'A': case 'B': case 'C':
 628                                if (!arg[2]) {
 629                                        if (argc <= 1)
 630                                                die(emsg_missing_context_len);
 631                                        scan = *++argv;
 632                                        argc--;
 633                                }
 634                                else
 635                                        scan = arg + 2;
 636                                break;
 637                        default:
 638                                scan = arg + 1;
 639                                break;
 640                        }
 641                        if (strtoul_ui(scan, 10, &num))
 642                                die(emsg_invalid_context_len, scan);
 643                        switch (arg[1]) {
 644                        case 'A':
 645                                opt.post_context = num;
 646                                break;
 647                        default:
 648                        case 'C':
 649                                opt.post_context = num;
 650                        case 'B':
 651                                opt.pre_context = num;
 652                                break;
 653                        }
 654                        continue;
 655                }
 656                if (!strcmp("-f", arg)) {
 657                        FILE *patterns;
 658                        int lno = 0;
 659                        char buf[1024];
 660                        if (argc <= 1)
 661                                die(emsg_missing_argument, arg);
 662                        patterns = fopen(argv[1], "r");
 663                        if (!patterns)
 664                                die("'%s': %s", argv[1], strerror(errno));
 665                        while (fgets(buf, sizeof(buf), patterns)) {
 666                                int len = strlen(buf);
 667                                if (len && buf[len-1] == '\n')
 668                                        buf[len-1] = 0;
 669                                /* ignore empty line like grep does */
 670                                if (!buf[0])
 671                                        continue;
 672                                append_grep_pattern(&opt, xstrdup(buf),
 673                                                    argv[1], ++lno,
 674                                                    GREP_PATTERN);
 675                        }
 676                        fclose(patterns);
 677                        argv++;
 678                        argc--;
 679                        continue;
 680                }
 681                if (!strcmp("--not", arg)) {
 682                        append_grep_pattern(&opt, arg, "command line", 0,
 683                                            GREP_NOT);
 684                        continue;
 685                }
 686                if (!strcmp("--and", arg)) {
 687                        append_grep_pattern(&opt, arg, "command line", 0,
 688                                            GREP_AND);
 689                        continue;
 690                }
 691                if (!strcmp("--or", arg))
 692                        continue; /* no-op */
 693                if (!strcmp("(", arg)) {
 694                        append_grep_pattern(&opt, arg, "command line", 0,
 695                                            GREP_OPEN_PAREN);
 696                        continue;
 697                }
 698                if (!strcmp(")", arg)) {
 699                        append_grep_pattern(&opt, arg, "command line", 0,
 700                                            GREP_CLOSE_PAREN);
 701                        continue;
 702                }
 703                if (!strcmp("--all-match", arg)) {
 704                        opt.all_match = 1;
 705                        continue;
 706                }
 707                if (!strcmp("-e", arg)) {
 708                        if (1 < argc) {
 709                                append_grep_pattern(&opt, argv[1],
 710                                                    "-e option", 0,
 711                                                    GREP_PATTERN);
 712                                argv++;
 713                                argc--;
 714                                continue;
 715                        }
 716                        die(emsg_missing_argument, arg);
 717                }
 718                if (!strcmp("--full-name", arg)) {
 719                        opt.relative = 0;
 720                        continue;
 721                }
 722                if (!strcmp("--", arg)) {
 723                        /* later processing wants to have this at argv[1] */
 724                        argv--;
 725                        argc++;
 726                        break;
 727                }
 728                if (*arg == '-')
 729                        usage(builtin_grep_usage);
 730
 731                /* First unrecognized non-option token */
 732                if (!opt.pattern_list) {
 733                        append_grep_pattern(&opt, arg, "command line", 0,
 734                                            GREP_PATTERN);
 735                        break;
 736                }
 737                else {
 738                        /* We are looking at the first path or rev;
 739                         * it is found at argv[1] after leaving the
 740                         * loop.
 741                         */
 742                        argc++; argv--;
 743                        break;
 744                }
 745        }
 746
 747        if (!opt.pattern_list)
 748                die("no pattern given.");
 749        if ((opt.regflags != REG_NEWLINE) && opt.fixed)
 750                die("cannot mix --fixed-strings and regexp");
 751        compile_grep_patterns(&opt);
 752
 753        /* Check revs and then paths */
 754        for (i = 1; i < argc; i++) {
 755                const char *arg = argv[i];
 756                unsigned char sha1[20];
 757                /* Is it a rev? */
 758                if (!get_sha1(arg, sha1)) {
 759                        struct object *object = parse_object(sha1);
 760                        if (!object)
 761                                die("bad object %s", arg);
 762                        add_object_array(object, arg, &list);
 763                        continue;
 764                }
 765                if (!strcmp(arg, "--")) {
 766                        i++;
 767                        seen_dashdash = 1;
 768                }
 769                break;
 770        }
 771
 772        /* The rest are paths */
 773        if (!seen_dashdash) {
 774                int j;
 775                for (j = i; j < argc; j++)
 776                        verify_filename(prefix, argv[j]);
 777        }
 778
 779        if (i < argc) {
 780                paths = get_pathspec(prefix, argv + i);
 781                if (opt.prefix_length && opt.relative) {
 782                        /* Make sure we do not get outside of paths */
 783                        for (i = 0; paths[i]; i++)
 784                                if (strncmp(prefix, paths[i], opt.prefix_length))
 785                                        die("git grep: cannot generate relative filenames containing '..'");
 786                }
 787        }
 788        else if (prefix) {
 789                paths = xcalloc(2, sizeof(const char *));
 790                paths[0] = prefix;
 791                paths[1] = NULL;
 792        }
 793
 794        if (!list.nr) {
 795                if (!cached)
 796                        setup_work_tree();
 797                return !grep_cache(&opt, paths, cached);
 798        }
 799
 800        if (cached)
 801                die("both --cached and trees are given.");
 802
 803        for (i = 0; i < list.nr; i++) {
 804                struct object *real_obj;
 805                real_obj = deref_tag(list.objects[i].item, NULL, 0);
 806                if (grep_object(&opt, paths, real_obj, list.objects[i].name))
 807                        hit = 1;
 808        }
 809        free_grep_patterns(&opt);
 810        return !hit;
 811}