builtin-grep.c

   1 /*
   2  * Builtin "git grep"
   3  *
   4  * Copyright (c) 2006 Junio C Hamano
   5  */
   6 #include "cache.h"
   7 #include "blob.h"
   8 #include "tree.h"
   9 #include "commit.h"
  10 #include "tag.h"
  11 #include "tree-walk.h"
  12 #include "builtin.h"
  13 #include "grep.h"
  14
  15 #ifndef NO_EXTERNAL_GREP
  16 #ifdef __unix__
  17 #define NO_EXTERNAL_GREP 0
  18 #else
  19 #define NO_EXTERNAL_GREP 1
  20 #endif
  21 #endif
  22
  23 static int builtin_grep;
  24
  25 static int grep_config(const char *var, const char *value, void *cb)
  26 {
  27         struct grep_opt *opt = cb;
  28
  29         if (!strcmp(var, "color.grep")) {
  30                 opt->color = git_config_colorbool(var, value, -1);
  31                 return 0;
  32         }
  33         if (!strcmp(var, "color.grep.external"))
  34                 return git_config_string(&(opt->color_external), var, value);
  35         if (!strcmp(var, "color.grep.match")) {
  36                 if (!value)
  37                         return config_error_nonbool(var);
  38                 color_parse(value, var, opt->color_match);
  39                 return 0;
  40         }
  41         return git_color_default_config(var, value, cb);
  42 }
  43
  44 /*
  45  * git grep pathspecs are somewhat different from diff-tree pathspecs;
  46  * pathname wildcards are allowed.
  47  */
  48 static int pathspec_matches(const char **paths, const char *name)
  49 {
  50         int namelen, i;
  51         if (!paths || !*paths)
  52                 return 1;
  53         namelen = strlen(name);
  54         for (i = 0; paths[i]; i++) {
  55                 const char *match = paths[i];
  56                 int matchlen = strlen(match);
  57                 const char *cp, *meta;
  58
  59                 if (!matchlen ||
  60                     ((matchlen <= namelen) &&
  61                      !strncmp(name, match, matchlen) &&
  62                      (match[matchlen-1] == '/' ||
  63                       name[matchlen] == '\0' || name[matchlen] == '/')))
  64                         return 1;
  65                 if (!fnmatch(match, name, 0))
  66                         return 1;
  67                 if (name[namelen-1] != '/')
  68                         continue;
  69
  70                 /* We are being asked if the directory ("name") is worth
  71                  * descending into.
  72                  *
  73                  * Find the longest leading directory name that does
  74                  * not have metacharacter in the pathspec; the name
  75                  * we are looking at must overlap with that directory.
  76                  */
  77                 for (cp = match, meta = NULL; cp - match < matchlen; cp++) {
  78                         char ch = *cp;
  79                         if (ch == '*' || ch == '[' || ch == '?') {
  80                                 meta = cp;
  81                                 break;
  82                         }
  83                 }
  84                 if (!meta)
  85                         meta = cp; /* fully literal */
  86
  87                 if (namelen <= meta - match) {
  88                         /* Looking at "Documentation/" and
  89                          * the pattern says "Documentation/howto/", or
  90                          * "Documentation/diff*.txt".  The name we
  91                          * have should match prefix.
  92                          */
  93                         if (!memcmp(match, name, namelen))
  94                                 return 1;
  95                         continue;
  96                 }
  97
  98                 if (meta - match < namelen) {
  99                         /* Looking at "Documentation/howto/" and
 100                          * the pattern says "Documentation/h*";
 101                          * match up to "Do.../h"; this avoids descending
 102                          * into "Documentation/technical/".
 103                          */
 104                         if (!memcmp(match, name, meta - match))
 105                                 return 1;
 106                         continue;
 107                 }
 108         }
 109         return 0;
 110 }
 111
 112 static int grep_sha1(struct grep_opt *opt, const unsigned char *sha1, const char *name, int tree_name_len)
 113 {
 114         unsigned long size;
 115         char *data;
 116         enum object_type type;
 117         char *to_free = NULL;
 118         int hit;
 119
 120         data = read_sha1_file(sha1, &type, &size);
 121         if (!data) {
 122                 error("'%s': unable to read %s", name, sha1_to_hex(sha1));
 123                 return 0;
 124         }
 125         if (opt->relative && opt->prefix_length) {
 126                 static char name_buf[PATH_MAX];
 127                 char *cp;
 128                 int name_len = strlen(name) - opt->prefix_length + 1;
 129
 130                 if (!tree_name_len)
 131                         name += opt->prefix_length;
 132                 else {
 133                         if (ARRAY_SIZE(name_buf) <= name_len)
 134                                 cp = to_free = xmalloc(name_len);
 135                         else
 136                                 cp = name_buf;
 137                         memcpy(cp, name, tree_name_len);
 138                         strcpy(cp + tree_name_len,
 139                                name + tree_name_len + opt->prefix_length);
 140                         name = cp;
 141                 }
 142         }
 143         hit = grep_buffer(opt, name, data, size);
 144         free(data);
 145         free(to_free);
 146         return hit;
 147 }
 148
 149 static int grep_file(struct grep_opt *opt, const char *filename)
 150 {
 151         struct stat st;
 152         int i;
 153         char *data;
 154         size_t sz;
 155
 156         if (lstat(filename, &st) < 0) {
 157         err_ret:
 158                 if (errno != ENOENT)
 159                         error("'%s': %s", filename, strerror(errno));
 160                 return 0;
 161         }
 162         if (!st.st_size)
 163                 return 0; /* empty file -- no grep hit */
 164         if (!S_ISREG(st.st_mode))
 165                 return 0;
 166         sz = xsize_t(st.st_size);
 167         i = open(filename, O_RDONLY);
 168         if (i < 0)
 169                 goto err_ret;
 170         data = xmalloc(sz + 1);
 171         if (st.st_size != read_in_full(i, data, sz)) {
 172                 error("'%s': short read %s", filename, strerror(errno));
 173                 close(i);
 174                 free(data);
 175                 return 0;
 176         }
 177         close(i);
 178         if (opt->relative && opt->prefix_length)
 179                 filename += opt->prefix_length;
 180         i = grep_buffer(opt, filename, data, sz);
 181         free(data);
 182         return i;
 183 }
 184
 185 #if !NO_EXTERNAL_GREP
 186 static int exec_grep(int argc, const char **argv)
 187 {
 188         pid_t pid;
 189         int status;
 190
 191         argv[argc] = NULL;
 192         pid = fork();
 193         if (pid < 0)
 194                 return pid;
 195         if (!pid) {
 196                 execvp("grep", (char **) argv);
 197                 exit(255);
 198         }
 199         while (waitpid(pid, &status, 0) < 0) {
 200                 if (errno == EINTR)
 201                         continue;
 202                 return -1;
 203         }
 204         if (WIFEXITED(status)) {
 205                 if (!WEXITSTATUS(status))
 206                         return 1;
 207                 return 0;
 208         }
 209         return -1;
 210 }
 211
 212 #define MAXARGS 1000
 213 #define ARGBUF 4096
 214 #define push_arg(a) do { \
 215         if (nr < MAXARGS) argv[nr++] = (a); \
 216         else die("maximum number of args exceeded"); \
 217         } while (0)
 218
 219 /*
 220  * If you send a singleton filename to grep, it does not give
 221  * the name of the file.  GNU grep has "-H" but we would want
 222  * that behaviour in a portable way.
 223  *
 224  * So we keep two pathnames in argv buffer unsent to grep in
 225  * the main loop if we need to do more than one grep.
 226  */
 227 static int flush_grep(struct grep_opt *opt,
 228                       int argc, int arg0, const char **argv, int *kept)
 229 {
 230         int status;
 231         int count = argc - arg0;
 232         const char *kept_0 = NULL;
 233
 234         if (count <= 2) {
 235                 /*
 236                  * Because we keep at least 2 paths in the call from
 237                  * the main loop (i.e. kept != NULL), and MAXARGS is
 238                  * far greater than 2, this usually is a call to
 239                  * conclude the grep.  However, the user could attempt
 240                  * to overflow the argv buffer by giving too many
 241                  * options to leave very small number of real
 242                  * arguments even for the call in the main loop.
 243                  */
 244                 if (kept)
 245                         die("insanely many options to grep");
 246
 247                 /*
 248                  * If we have two or more paths, we do not have to do
 249                  * anything special, but we need to push /dev/null to
 250                  * get "-H" behaviour of GNU grep portably but when we
 251                  * are not doing "-l" nor "-L" nor "-c".
 252                  */
 253                 if (count == 1 &&
 254                     !opt->name_only &&
 255                     !opt->unmatch_name_only &&
 256                     !opt->count) {
 257                         argv[argc++] = "/dev/null";
 258                         argv[argc] = NULL;
 259                 }
 260         }
 261
 262         else if (kept) {
 263                 /*
 264                  * Called because we found many paths and haven't finished
 265                  * iterating over the cache yet.  We keep two paths
 266                  * for the concluding call.  argv[argc-2] and argv[argc-1]
 267                  * has the last two paths, so save the first one away,
 268                  * replace it with NULL while sending the list to grep,
 269                  * and recover them after we are done.
 270                  */
 271                 *kept = 2;
 272                 kept_0 = argv[argc-2];
 273                 argv[argc-2] = NULL;
 274                 argc -= 2;
 275         }
 276
 277         status = exec_grep(argc, argv);
 278
 279         if (kept_0) {
 280                 /*
 281                  * Then recover them.  Now the last arg is beyond the
 282                  * terminating NULL which is at argc, and the second
 283                  * from the last is what we saved away in kept_0
 284                  */
 285                 argv[arg0++] = kept_0;
 286                 argv[arg0] = argv[argc+1];
 287         }
 288         return status;
 289 }
 290
 291 static void grep_add_color(struct strbuf *sb, const char *escape_seq)
 292 {
 293         size_t orig_len = sb->len;
 294
 295         while (*escape_seq) {
 296                 if (*escape_seq == 'm')
 297                         strbuf_addch(sb, ';');
 298                 else if (*escape_seq != '\033' && *escape_seq  != '[')
 299                         strbuf_addch(sb, *escape_seq);
 300                 escape_seq++;
 301         }
 302         if (sb->len > orig_len && sb->buf[sb->len - 1] == ';')
 303                 strbuf_setlen(sb, sb->len - 1);
 304 }
 305
 306 static int external_grep(struct grep_opt *opt, const char **paths, int cached)
 307 {
 308         int i, nr, argc, hit, len, status;
 309         const char *argv[MAXARGS+1];
 310         char randarg[ARGBUF];
 311         char *argptr = randarg;
 312         struct grep_pat *p;
 313
 314         if (opt->extended || (opt->relative && opt->prefix_length))
 315                 return -1;
 316         len = nr = 0;
 317         push_arg("grep");
 318         if (opt->fixed)
 319                 push_arg("-F");
 320         if (opt->linenum)
 321                 push_arg("-n");
 322         if (!opt->pathname)
 323                 push_arg("-h");
 324         if (opt->regflags & REG_EXTENDED)
 325                 push_arg("-E");
 326         if (opt->regflags & REG_ICASE)
 327                 push_arg("-i");
 328         if (opt->binary == GREP_BINARY_NOMATCH)
 329                 push_arg("-I");
 330         if (opt->word_regexp)
 331                 push_arg("-w");
 332         if (opt->name_only)
 333                 push_arg("-l");
 334         if (opt->unmatch_name_only)
 335                 push_arg("-L");
 336         if (opt->null_following_name)
 337                 /* in GNU grep git's "-z" translates to "-Z" */
 338                 push_arg("-Z");
 339         if (opt->count)
 340                 push_arg("-c");
 341         if (opt->post_context || opt->pre_context) {
 342                 if (opt->post_context != opt->pre_context) {
 343                         if (opt->pre_context) {
 344                                 push_arg("-B");
 345                                 len += snprintf(argptr, sizeof(randarg)-len,
 346                                                 "%u", opt->pre_context) + 1;
 347                                 if (sizeof(randarg) <= len)
 348                                         die("maximum length of args exceeded");
 349                                 push_arg(argptr);
 350                                 argptr += len;
 351                         }
 352                         if (opt->post_context) {
 353                                 push_arg("-A");
 354                                 len += snprintf(argptr, sizeof(randarg)-len,
 355                                                 "%u", opt->post_context) + 1;
 356                                 if (sizeof(randarg) <= len)
 357                                         die("maximum length of args exceeded");
 358                                 push_arg(argptr);
 359                                 argptr += len;
 360                         }
 361                 }
 362                 else {
 363                         push_arg("-C");
 364                         len += snprintf(argptr, sizeof(randarg)-len,
 365                                         "%u", opt->post_context) + 1;
 366                         if (sizeof(randarg) <= len)
 367                                 die("maximum length of args exceeded");
 368                         push_arg(argptr);
 369                         argptr += len;
 370                 }
 371         }
 372         for (p = opt->pattern_list; p; p = p->next) {
 373                 push_arg("-e");
 374                 push_arg(p->pattern);
 375         }
 376         if (opt->color) {
 377                 struct strbuf sb = STRBUF_INIT;
 378
 379                 grep_add_color(&sb, opt->color_match);
 380                 setenv("GREP_COLOR", sb.buf, 1);
 381
 382                 strbuf_reset(&sb);
 383                 strbuf_addstr(&sb, "mt=");
 384                 grep_add_color(&sb, opt->color_match);
 385                 strbuf_addstr(&sb, ":sl=:cx=:fn=:ln=:bn=:se=");
 386                 setenv("GREP_COLORS", sb.buf, 1);
 387
 388                 strbuf_release(&sb);
 389
 390                 if (opt->color_external && strlen(opt->color_external) > 0)
 391                         push_arg(opt->color_external);
 392         }
 393
 394         hit = 0;
 395         argc = nr;
 396         for (i = 0; i < active_nr; i++) {
 397                 struct cache_entry *ce = active_cache[i];
 398                 char *name;
 399                 int kept;
 400                 if (!S_ISREG(ce->ce_mode))
 401                         continue;
 402                 if (!pathspec_matches(paths, ce->name))
 403                         continue;
 404                 name = ce->name;
 405                 if (name[0] == '-') {
 406                         int len = ce_namelen(ce);
 407                         name = xmalloc(len + 3);
 408                         memcpy(name, "./", 2);
 409                         memcpy(name + 2, ce->name, len + 1);
 410                 }
 411                 argv[argc++] = name;
 412                 if (MAXARGS <= argc) {
 413                         status = flush_grep(opt, argc, nr, argv, &kept);
 414                         if (0 < status)
 415                                 hit = 1;
 416                         argc = nr + kept;
 417                 }
 418                 if (ce_stage(ce)) {
 419                         do {
 420                                 i++;
 421                         } while (i < active_nr &&
 422                                  !strcmp(ce->name, active_cache[i]->name));
 423                         i--; /* compensate for loop control */
 424                 }
 425         }
 426         if (argc > nr) {
 427                 status = flush_grep(opt, argc, nr, argv, NULL);
 428                 if (0 < status)
 429                         hit = 1;
 430         }
 431         return hit;
 432 }
 433 #endif
 434
 435 static int grep_cache(struct grep_opt *opt, const char **paths, int cached)
 436 {
 437         int hit = 0;
 438         int nr;
 439         read_cache();
 440
 441 #if !NO_EXTERNAL_GREP
 442         /*
 443          * Use the external "grep" command for the case where
 444          * we grep through the checked-out files. It tends to
 445          * be a lot more optimized
 446          */
 447         if (!cached && !builtin_grep) {
 448                 hit = external_grep(opt, paths, cached);
 449                 if (hit >= 0)
 450                         return hit;
 451                 hit = 0;
 452         }
 453 #endif
 454
 455         for (nr = 0; nr < active_nr; nr++) {
 456                 struct cache_entry *ce = active_cache[nr];
 457                 if (!S_ISREG(ce->ce_mode))
 458                         continue;
 459                 if (!pathspec_matches(paths, ce->name))
 460                         continue;
 461                 /*
 462                  * If CE_VALID is on, we assume worktree file and its cache entry
 463                  * are identical, even if worktree file has been modified, so use
 464                  * cache version instead
 465                  */
 466                 if (cached || (ce->ce_flags & CE_VALID)) {
 467                         if (ce_stage(ce))
 468                                 continue;
 469                         hit |= grep_sha1(opt, ce->sha1, ce->name, 0);
 470                 }
 471                 else
 472                         hit |= grep_file(opt, ce->name);
 473                 if (ce_stage(ce)) {
 474                         do {
 475                                 nr++;
 476                         } while (nr < active_nr &&
 477                                  !strcmp(ce->name, active_cache[nr]->name));
 478                         nr--; /* compensate for loop control */
 479                 }
 480         }
 481         free_grep_patterns(opt);
 482         return hit;
 483 }
 484
 485 static int grep_tree(struct grep_opt *opt, const char **paths,
 486                      struct tree_desc *tree,
 487                      const char *tree_name, const char *base)
 488 {
 489         int len;
 490         int hit = 0;
 491         struct name_entry entry;
 492         char *down;
 493         int tn_len = strlen(tree_name);
 494         struct strbuf pathbuf;
 495
 496         strbuf_init(&pathbuf, PATH_MAX + tn_len);
 497
 498         if (tn_len) {
 499                 strbuf_add(&pathbuf, tree_name, tn_len);
 500                 strbuf_addch(&pathbuf, ':');
 501                 tn_len = pathbuf.len;
 502         }
 503         strbuf_addstr(&pathbuf, base);
 504         len = pathbuf.len;
 505
 506         while (tree_entry(tree, &entry)) {
 507                 int te_len = tree_entry_len(entry.path, entry.sha1);
 508                 pathbuf.len = len;
 509                 strbuf_add(&pathbuf, entry.path, te_len);
 510
 511                 if (S_ISDIR(entry.mode))
 512                         /* Match "abc/" against pathspec to
 513                          * decide if we want to descend into "abc"
 514                          * directory.
 515                          */
 516                         strbuf_addch(&pathbuf, '/');
 517
 518                 down = pathbuf.buf + tn_len;
 519                 if (!pathspec_matches(paths, down))
 520                         ;
 521                 else if (S_ISREG(entry.mode))
 522                         hit |= grep_sha1(opt, entry.sha1, pathbuf.buf, tn_len);
 523                 else if (S_ISDIR(entry.mode)) {
 524                         enum object_type type;
 525                         struct tree_desc sub;
 526                         void *data;
 527                         unsigned long size;
 528
 529                         data = read_sha1_file(entry.sha1, &type, &size);
 530                         if (!data)
 531                                 die("unable to read tree (%s)",
 532                                     sha1_to_hex(entry.sha1));
 533                         init_tree_desc(&sub, data, size);
 534                         hit |= grep_tree(opt, paths, &sub, tree_name, down);
 535                         free(data);
 536                 }
 537         }
 538         strbuf_release(&pathbuf);
 539         return hit;
 540 }
 541
 542 static int grep_object(struct grep_opt *opt, const char **paths,
 543                        struct object *obj, const char *name)
 544 {
 545         if (obj->type == OBJ_BLOB)
 546                 return grep_sha1(opt, obj->sha1, name, 0);
 547         if (obj->type == OBJ_COMMIT || obj->type == OBJ_TREE) {
 548                 struct tree_desc tree;
 549                 void *data;
 550                 unsigned long size;
 551                 int hit;
 552                 data = read_object_with_reference(obj->sha1, tree_type,
 553                                                   &size, NULL);
 554                 if (!data)
 555                         die("unable to read tree (%s)", sha1_to_hex(obj->sha1));
 556                 init_tree_desc(&tree, data, size);
 557                 hit = grep_tree(opt, paths, &tree, name, "");
 558                 free(data);
 559                 return hit;
 560         }
 561         die("unable to grep from object of type %s", typename(obj->type));
 562 }
 563
 564 static const char builtin_grep_usage[] =
 565 "git grep <option>* [-e] <pattern> <rev>* [[--] <path>...]";
 566
 567 static const char emsg_invalid_context_len[] =
 568 "%s: invalid context length argument";
 569 static const char emsg_missing_context_len[] =
 570 "missing context length argument";
 571 static const char emsg_missing_argument[] =
 572 "option requires an argument -%s";
 573
 574 int cmd_grep(int argc, const char **argv, const char *prefix)
 575 {
 576         int hit = 0;
 577         int cached = 0;
 578         int seen_dashdash = 0;
 579         struct grep_opt opt;
 580         struct object_array list = { 0, 0, NULL };
 581         const char **paths = NULL;
 582         int i;
 583
 584         memset(&opt, 0, sizeof(opt));
 585         opt.prefix_length = (prefix && *prefix) ? strlen(prefix) : 0;
 586         opt.relative = 1;
 587         opt.pathname = 1;
 588         opt.pattern_tail = &opt.pattern_list;
 589         opt.regflags = REG_NEWLINE;
 590
 591         strcpy(opt.color_match, GIT_COLOR_RED GIT_COLOR_BOLD);
 592         opt.color = -1;
 593         git_config(grep_config, &opt);
 594         if (opt.color == -1)
 595                 opt.color = git_use_color_default;
 596
 597         /*
 598          * If there is no -- then the paths must exist in the working
 599          * tree.  If there is no explicit pattern specified with -e or
 600          * -f, we take the first unrecognized non option to be the
 601          * pattern, but then what follows it must be zero or more
 602          * valid refs up to the -- (if exists), and then existing
 603          * paths.  If there is an explicit pattern, then the first
 604          * unrecognized non option is the beginning of the refs list
 605          * that continues up to the -- (if exists), and then paths.
 606          */
 607
 608         while (1 < argc) {
 609                 const char *arg = argv[1];
 610                 argc--; argv++;
 611                 if (!strcmp("--cached", arg)) {
 612                         cached = 1;
 613                         continue;
 614                 }
 615                 if (!strcmp("--no-ext-grep", arg)) {
 616                         builtin_grep = 1;
 617                         continue;
 618                 }
 619                 if (!strcmp("-a", arg) ||
 620                     !strcmp("--text", arg)) {
 621                         opt.binary = GREP_BINARY_TEXT;
 622                         continue;
 623                 }
 624                 if (!strcmp("-i", arg) ||
 625                     !strcmp("--ignore-case", arg)) {
 626                         opt.regflags |= REG_ICASE;
 627                         continue;
 628                 }
 629                 if (!strcmp("-I", arg)) {
 630                         opt.binary = GREP_BINARY_NOMATCH;
 631                         continue;
 632                 }
 633                 if (!strcmp("-v", arg) ||
 634                     !strcmp("--invert-match", arg)) {
 635                         opt.invert = 1;
 636                         continue;
 637                 }
 638                 if (!strcmp("-E", arg) ||
 639                     !strcmp("--extended-regexp", arg)) {
 640                         opt.regflags |= REG_EXTENDED;
 641                         continue;
 642                 }
 643                 if (!strcmp("-F", arg) ||
 644                     !strcmp("--fixed-strings", arg)) {
 645                         opt.fixed = 1;
 646                         continue;
 647                 }
 648                 if (!strcmp("-G", arg) ||
 649                     !strcmp("--basic-regexp", arg)) {
 650                         opt.regflags &= ~REG_EXTENDED;
 651                         continue;
 652                 }
 653                 if (!strcmp("-n", arg)) {
 654                         opt.linenum = 1;
 655                         continue;
 656                 }
 657                 if (!strcmp("-h", arg)) {
 658                         opt.pathname = 0;
 659                         continue;
 660                 }
 661                 if (!strcmp("-H", arg)) {
 662                         opt.pathname = 1;
 663                         continue;
 664                 }
 665                 if (!strcmp("-l", arg) ||
 666                     !strcmp("--name-only", arg) ||
 667                     !strcmp("--files-with-matches", arg)) {
 668                         opt.name_only = 1;
 669                         continue;
 670                 }
 671                 if (!strcmp("-L", arg) ||
 672                     !strcmp("--files-without-match", arg)) {
 673                         opt.unmatch_name_only = 1;
 674                         continue;
 675                 }
 676                 if (!strcmp("-z", arg) ||
 677                     !strcmp("--null", arg)) {
 678                         opt.null_following_name = 1;
 679                         continue;
 680                 }
 681                 if (!strcmp("-c", arg) ||
 682                     !strcmp("--count", arg)) {
 683                         opt.count = 1;
 684                         continue;
 685                 }
 686                 if (!strcmp("-w", arg) ||
 687                     !strcmp("--word-regexp", arg)) {
 688                         opt.word_regexp = 1;
 689                         continue;
 690                 }
 691                 if (!prefixcmp(arg, "-A") ||
 692                     !prefixcmp(arg, "-B") ||
 693                     !prefixcmp(arg, "-C") ||
 694                     (arg[0] == '-' && '1' <= arg[1] && arg[1] <= '9')) {
 695                         unsigned num;
 696                         const char *scan;
 697                         switch (arg[1]) {
 698                         case 'A': case 'B': case 'C':
 699                                 if (!arg[2]) {
 700                                         if (argc <= 1)
 701                                                 die(emsg_missing_context_len);
 702                                         scan = *++argv;
 703                                         argc--;
 704                                 }
 705                                 else
 706                                         scan = arg + 2;
 707                                 break;
 708                         default:
 709                                 scan = arg + 1;
 710                                 break;
 711                         }
 712                         if (strtoul_ui(scan, 10, &num))
 713                                 die(emsg_invalid_context_len, scan);
 714                         switch (arg[1]) {
 715                         case 'A':
 716                                 opt.post_context = num;
 717                                 break;
 718                         default:
 719                         case 'C':
 720                                 opt.post_context = num;
 721                         case 'B':
 722                                 opt.pre_context = num;
 723                                 break;
 724                         }
 725                         continue;
 726                 }
 727                 if (!strcmp("-f", arg)) {
 728                         FILE *patterns;
 729                         int lno = 0;
 730                         char buf[1024];
 731                         if (argc <= 1)
 732                                 die(emsg_missing_argument, arg);
 733                         patterns = fopen(argv[1], "r");
 734                         if (!patterns)
 735                                 die("'%s': %s", argv[1], strerror(errno));
 736                         while (fgets(buf, sizeof(buf), patterns)) {
 737                                 int len = strlen(buf);
 738                                 if (len && buf[len-1] == '\n')
 739                                         buf[len-1] = 0;
 740                                 /* ignore empty line like grep does */
 741                                 if (!buf[0])
 742                                         continue;
 743                                 append_grep_pattern(&opt, xstrdup(buf),
 744                                                     argv[1], ++lno,
 745                                                     GREP_PATTERN);
 746                         }
 747                         fclose(patterns);
 748                         argv++;
 749                         argc--;
 750                         continue;
 751                 }
 752                 if (!strcmp("--not", arg)) {
 753                         append_grep_pattern(&opt, arg, "command line", 0,
 754                                             GREP_NOT);
 755                         continue;
 756                 }
 757                 if (!strcmp("--and", arg)) {
 758                         append_grep_pattern(&opt, arg, "command line", 0,
 759                                             GREP_AND);
 760                         continue;
 761                 }
 762                 if (!strcmp("--or", arg))
 763                         continue; /* no-op */
 764                 if (!strcmp("(", arg)) {
 765                         append_grep_pattern(&opt, arg, "command line", 0,
 766                                             GREP_OPEN_PAREN);
 767                         continue;
 768                 }
 769                 if (!strcmp(")", arg)) {
 770                         append_grep_pattern(&opt, arg, "command line", 0,
 771                                             GREP_CLOSE_PAREN);
 772                         continue;
 773                 }
 774                 if (!strcmp("--all-match", arg)) {
 775                         opt.all_match = 1;
 776                         continue;
 777                 }
 778                 if (!strcmp("-e", arg)) {
 779                         if (1 < argc) {
 780                                 append_grep_pattern(&opt, argv[1],
 781                                                     "-e option", 0,
 782                                                     GREP_PATTERN);
 783                                 argv++;
 784                                 argc--;
 785                                 continue;
 786                         }
 787                         die(emsg_missing_argument, arg);
 788                 }
 789                 if (!strcmp("--full-name", arg)) {
 790                         opt.relative = 0;
 791                         continue;
 792                 }
 793                 if (!strcmp("--color", arg)) {
 794                         opt.color = 1;
 795                         continue;
 796                 }
 797                 if (!strcmp("--no-color", arg)) {
 798                         opt.color = 0;
 799                         continue;
 800                 }
 801                 if (!strcmp("--", arg)) {
 802                         /* later processing wants to have this at argv[1] */
 803                         argv--;
 804                         argc++;
 805                         break;
 806                 }
 807                 if (*arg == '-')
 808                         usage(builtin_grep_usage);
 809
 810                 /* First unrecognized non-option token */
 811                 if (!opt.pattern_list) {
 812                         append_grep_pattern(&opt, arg, "command line", 0,
 813                                             GREP_PATTERN);
 814                         break;
 815                 }
 816                 else {
 817                         /* We are looking at the first path or rev;
 818                          * it is found at argv[1] after leaving the
 819                          * loop.
 820                          */
 821                         argc++; argv--;
 822                         break;
 823                 }
 824         }
 825
 826         if (opt.color && !opt.color_external)
 827                 builtin_grep = 1;
 828         if (!opt.pattern_list)
 829                 die("no pattern given.");
 830         if ((opt.regflags != REG_NEWLINE) && opt.fixed)
 831                 die("cannot mix --fixed-strings and regexp");
 832         compile_grep_patterns(&opt);
 833
 834         /* Check revs and then paths */
 835         for (i = 1; i < argc; i++) {
 836                 const char *arg = argv[i];
 837                 unsigned char sha1[20];
 838                 /* Is it a rev? */
 839                 if (!get_sha1(arg, sha1)) {
 840                         struct object *object = parse_object(sha1);
 841                         if (!object)
 842                                 die("bad object %s", arg);
 843                         add_object_array(object, arg, &list);
 844                         continue;
 845                 }
 846                 if (!strcmp(arg, "--")) {
 847                         i++;
 848                         seen_dashdash = 1;
 849                 }
 850                 break;
 851         }
 852
 853         /* The rest are paths */
 854         if (!seen_dashdash) {
 855                 int j;
 856                 for (j = i; j < argc; j++)
 857                         verify_filename(prefix, argv[j]);
 858         }
 859
 860         if (i < argc) {
 861                 paths = get_pathspec(prefix, argv + i);
 862                 if (opt.prefix_length && opt.relative) {
 863                         /* Make sure we do not get outside of paths */
 864                         for (i = 0; paths[i]; i++)
 865                                 if (strncmp(prefix, paths[i], opt.prefix_length))
 866                                         die("git grep: cannot generate relative filenames containing '..'");
 867                 }
 868         }
 869         else if (prefix) {
 870                 paths = xcalloc(2, sizeof(const char *));
 871                 paths[0] = prefix;
 872                 paths[1] = NULL;
 873         }
 874
 875         if (!list.nr) {
 876                 if (!cached)
 877                         setup_work_tree();
 878                 return !grep_cache(&opt, paths, cached);
 879         }
 880
 881         if (cached)
 882                 die("both --cached and trees are given.");
 883
 884         for (i = 0; i < list.nr; i++) {
 885                 struct object *real_obj;
 886                 real_obj = deref_tag(list.objects[i].item, NULL, 0);
 887                 if (grep_object(&opt, paths, real_obj, list.objects[i].name))
 888                         hit = 1;
 889         }
 890         free_grep_patterns(&opt);
 891         return !hit;
 892 }