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, "grep.color") || !strcmp(var, "color.grep")) {
  30                 opt->color = git_config_colorbool(var, value, -1);
  31                 return 0;
  32         }
  33         if (!strcmp(var, "grep.color.external") ||
  34             !strcmp(var, "color.grep.external")) {
  35                 return git_config_string(&(opt->color_external), var, value);
  36         }
  37         if (!strcmp(var, "grep.color.match") ||
  38             !strcmp(var, "color.grep.match")) {
  39                 if (!value)
  40                         return config_error_nonbool(var);
  41                 color_parse(value, var, opt->color_match);
  42                 return 0;
  43         }
  44         return git_color_default_config(var, value, cb);
  45 }
  46
  47 /*
  48  * git grep pathspecs are somewhat different from diff-tree pathspecs;
  49  * pathname wildcards are allowed.
  50  */
  51 static int pathspec_matches(const char **paths, const char *name)
  52 {
  53         int namelen, i;
  54         if (!paths || !*paths)
  55                 return 1;
  56         namelen = strlen(name);
  57         for (i = 0; paths[i]; i++) {
  58                 const char *match = paths[i];
  59                 int matchlen = strlen(match);
  60                 const char *cp, *meta;
  61
  62                 if (!matchlen ||
  63                     ((matchlen <= namelen) &&
  64                      !strncmp(name, match, matchlen) &&
  65                      (match[matchlen-1] == '/' ||
  66                       name[matchlen] == '\0' || name[matchlen] == '/')))
  67                         return 1;
  68                 if (!fnmatch(match, name, 0))
  69                         return 1;
  70                 if (name[namelen-1] != '/')
  71                         continue;
  72
  73                 /* We are being asked if the directory ("name") is worth
  74                  * descending into.
  75                  *
  76                  * Find the longest leading directory name that does
  77                  * not have metacharacter in the pathspec; the name
  78                  * we are looking at must overlap with that directory.
  79                  */
  80                 for (cp = match, meta = NULL; cp - match < matchlen; cp++) {
  81                         char ch = *cp;
  82                         if (ch == '*' || ch == '[' || ch == '?') {
  83                                 meta = cp;
  84                                 break;
  85                         }
  86                 }
  87                 if (!meta)
  88                         meta = cp; /* fully literal */
  89
  90                 if (namelen <= meta - match) {
  91                         /* Looking at "Documentation/" and
  92                          * the pattern says "Documentation/howto/", or
  93                          * "Documentation/diff*.txt".  The name we
  94                          * have should match prefix.
  95                          */
  96                         if (!memcmp(match, name, namelen))
  97                                 return 1;
  98                         continue;
  99                 }
 100
 101                 if (meta - match < namelen) {
 102                         /* Looking at "Documentation/howto/" and
 103                          * the pattern says "Documentation/h*";
 104                          * match up to "Do.../h"; this avoids descending
 105                          * into "Documentation/technical/".
 106                          */
 107                         if (!memcmp(match, name, meta - match))
 108                                 return 1;
 109                         continue;
 110                 }
 111         }
 112         return 0;
 113 }
 114
 115 static int grep_sha1(struct grep_opt *opt, const unsigned char *sha1, const char *name, int tree_name_len)
 116 {
 117         unsigned long size;
 118         char *data;
 119         enum object_type type;
 120         char *to_free = NULL;
 121         int hit;
 122
 123         data = read_sha1_file(sha1, &type, &size);
 124         if (!data) {
 125                 error("'%s': unable to read %s", name, sha1_to_hex(sha1));
 126                 return 0;
 127         }
 128         if (opt->relative && opt->prefix_length) {
 129                 static char name_buf[PATH_MAX];
 130                 char *cp;
 131                 int name_len = strlen(name) - opt->prefix_length + 1;
 132
 133                 if (!tree_name_len)
 134                         name += opt->prefix_length;
 135                 else {
 136                         if (ARRAY_SIZE(name_buf) <= name_len)
 137                                 cp = to_free = xmalloc(name_len);
 138                         else
 139                                 cp = name_buf;
 140                         memcpy(cp, name, tree_name_len);
 141                         strcpy(cp + tree_name_len,
 142                                name + tree_name_len + opt->prefix_length);
 143                         name = cp;
 144                 }
 145         }
 146         hit = grep_buffer(opt, name, data, size);
 147         free(data);
 148         free(to_free);
 149         return hit;
 150 }
 151
 152 static int grep_file(struct grep_opt *opt, const char *filename)
 153 {
 154         struct stat st;
 155         int i;
 156         char *data;
 157         size_t sz;
 158
 159         if (lstat(filename, &st) < 0) {
 160         err_ret:
 161                 if (errno != ENOENT)
 162                         error("'%s': %s", filename, strerror(errno));
 163                 return 0;
 164         }
 165         if (!st.st_size)
 166                 return 0; /* empty file -- no grep hit */
 167         if (!S_ISREG(st.st_mode))
 168                 return 0;
 169         sz = xsize_t(st.st_size);
 170         i = open(filename, O_RDONLY);
 171         if (i < 0)
 172                 goto err_ret;
 173         data = xmalloc(sz + 1);
 174         if (st.st_size != read_in_full(i, data, sz)) {
 175                 error("'%s': short read %s", filename, strerror(errno));
 176                 close(i);
 177                 free(data);
 178                 return 0;
 179         }
 180         close(i);
 181         if (opt->relative && opt->prefix_length)
 182                 filename += opt->prefix_length;
 183         i = grep_buffer(opt, filename, data, sz);
 184         free(data);
 185         return i;
 186 }
 187
 188 #if !NO_EXTERNAL_GREP
 189 static int exec_grep(int argc, const char **argv)
 190 {
 191         pid_t pid;
 192         int status;
 193
 194         argv[argc] = NULL;
 195         pid = fork();
 196         if (pid < 0)
 197                 return pid;
 198         if (!pid) {
 199                 execvp("grep", (char **) argv);
 200                 exit(255);
 201         }
 202         while (waitpid(pid, &status, 0) < 0) {
 203                 if (errno == EINTR)
 204                         continue;
 205                 return -1;
 206         }
 207         if (WIFEXITED(status)) {
 208                 if (!WEXITSTATUS(status))
 209                         return 1;
 210                 return 0;
 211         }
 212         return -1;
 213 }
 214
 215 #define MAXARGS 1000
 216 #define ARGBUF 4096
 217 #define push_arg(a) do { \
 218         if (nr < MAXARGS) argv[nr++] = (a); \
 219         else die("maximum number of args exceeded"); \
 220         } while (0)
 221
 222 /*
 223  * If you send a singleton filename to grep, it does not give
 224  * the name of the file.  GNU grep has "-H" but we would want
 225  * that behaviour in a portable way.
 226  *
 227  * So we keep two pathnames in argv buffer unsent to grep in
 228  * the main loop if we need to do more than one grep.
 229  */
 230 static int flush_grep(struct grep_opt *opt,
 231                       int argc, int arg0, const char **argv, int *kept)
 232 {
 233         int status;
 234         int count = argc - arg0;
 235         const char *kept_0 = NULL;
 236
 237         if (count <= 2) {
 238                 /*
 239                  * Because we keep at least 2 paths in the call from
 240                  * the main loop (i.e. kept != NULL), and MAXARGS is
 241                  * far greater than 2, this usually is a call to
 242                  * conclude the grep.  However, the user could attempt
 243                  * to overflow the argv buffer by giving too many
 244                  * options to leave very small number of real
 245                  * arguments even for the call in the main loop.
 246                  */
 247                 if (kept)
 248                         die("insanely many options to grep");
 249
 250                 /*
 251                  * If we have two or more paths, we do not have to do
 252                  * anything special, but we need to push /dev/null to
 253                  * get "-H" behaviour of GNU grep portably but when we
 254                  * are not doing "-l" nor "-L" nor "-c".
 255                  */
 256                 if (count == 1 &&
 257                     !opt->name_only &&
 258                     !opt->unmatch_name_only &&
 259                     !opt->count) {
 260                         argv[argc++] = "/dev/null";
 261                         argv[argc] = NULL;
 262                 }
 263         }
 264
 265         else if (kept) {
 266                 /*
 267                  * Called because we found many paths and haven't finished
 268                  * iterating over the cache yet.  We keep two paths
 269                  * for the concluding call.  argv[argc-2] and argv[argc-1]
 270                  * has the last two paths, so save the first one away,
 271                  * replace it with NULL while sending the list to grep,
 272                  * and recover them after we are done.
 273                  */
 274                 *kept = 2;
 275                 kept_0 = argv[argc-2];
 276                 argv[argc-2] = NULL;
 277                 argc -= 2;
 278         }
 279
 280         status = exec_grep(argc, argv);
 281
 282         if (kept_0) {
 283                 /*
 284                  * Then recover them.  Now the last arg is beyond the
 285                  * terminating NULL which is at argc, and the second
 286                  * from the last is what we saved away in kept_0
 287                  */
 288                 argv[arg0++] = kept_0;
 289                 argv[arg0] = argv[argc+1];
 290         }
 291         return status;
 292 }
 293
 294 static void grep_add_color(struct strbuf *sb, const char *escape_seq)
 295 {
 296         size_t orig_len = sb->len;
 297
 298         while (*escape_seq) {
 299                 if (*escape_seq == 'm')
 300                         strbuf_addch(sb, ';');
 301                 else if (*escape_seq != '\033' && *escape_seq  != '[')
 302                         strbuf_addch(sb, *escape_seq);
 303                 escape_seq++;
 304         }
 305         if (sb->len > orig_len && sb->buf[sb->len - 1] == ';')
 306                 strbuf_setlen(sb, sb->len - 1);
 307 }
 308
 309 static int external_grep(struct grep_opt *opt, const char **paths, int cached)
 310 {
 311         int i, nr, argc, hit, len, status;
 312         const char *argv[MAXARGS+1];
 313         char randarg[ARGBUF];
 314         char *argptr = randarg;
 315         struct grep_pat *p;
 316
 317         if (opt->extended || (opt->relative && opt->prefix_length))
 318                 return -1;
 319         len = nr = 0;
 320         push_arg("grep");
 321         if (opt->fixed)
 322                 push_arg("-F");
 323         if (opt->linenum)
 324                 push_arg("-n");
 325         if (!opt->pathname)
 326                 push_arg("-h");
 327         if (opt->regflags & REG_EXTENDED)
 328                 push_arg("-E");
 329         if (opt->regflags & REG_ICASE)
 330                 push_arg("-i");
 331         if (opt->binary == GREP_BINARY_NOMATCH)
 332                 push_arg("-I");
 333         if (opt->word_regexp)
 334                 push_arg("-w");
 335         if (opt->name_only)
 336                 push_arg("-l");
 337         if (opt->unmatch_name_only)
 338                 push_arg("-L");
 339         if (opt->null_following_name)
 340                 /* in GNU grep git's "-z" translates to "-Z" */
 341                 push_arg("-Z");
 342         if (opt->count)
 343                 push_arg("-c");
 344         if (opt->post_context || opt->pre_context) {
 345                 if (opt->post_context != opt->pre_context) {
 346                         if (opt->pre_context) {
 347                                 push_arg("-B");
 348                                 len += snprintf(argptr, sizeof(randarg)-len,
 349                                                 "%u", opt->pre_context) + 1;
 350                                 if (sizeof(randarg) <= len)
 351                                         die("maximum length of args exceeded");
 352                                 push_arg(argptr);
 353                                 argptr += len;
 354                         }
 355                         if (opt->post_context) {
 356                                 push_arg("-A");
 357                                 len += snprintf(argptr, sizeof(randarg)-len,
 358                                                 "%u", opt->post_context) + 1;
 359                                 if (sizeof(randarg) <= len)
 360                                         die("maximum length of args exceeded");
 361                                 push_arg(argptr);
 362                                 argptr += len;
 363                         }
 364                 }
 365                 else {
 366                         push_arg("-C");
 367                         len += snprintf(argptr, sizeof(randarg)-len,
 368                                         "%u", opt->post_context) + 1;
 369                         if (sizeof(randarg) <= len)
 370                                 die("maximum length of args exceeded");
 371                         push_arg(argptr);
 372                         argptr += len;
 373                 }
 374         }
 375         for (p = opt->pattern_list; p; p = p->next) {
 376                 push_arg("-e");
 377                 push_arg(p->pattern);
 378         }
 379         if (opt->color) {
 380                 struct strbuf sb = STRBUF_INIT;
 381
 382                 grep_add_color(&sb, opt->color_match);
 383                 setenv("GREP_COLOR", sb.buf, 1);
 384
 385                 strbuf_reset(&sb);
 386                 strbuf_addstr(&sb, "mt=");
 387                 grep_add_color(&sb, opt->color_match);
 388                 strbuf_addstr(&sb, ":sl=:cx=:fn=:ln=:bn=:se=");
 389                 setenv("GREP_COLORS", sb.buf, 1);
 390
 391                 strbuf_release(&sb);
 392
 393                 if (opt->color_external && strlen(opt->color_external) > 0)
 394                         push_arg(opt->color_external);
 395         }
 396
 397         hit = 0;
 398         argc = nr;
 399         for (i = 0; i < active_nr; i++) {
 400                 struct cache_entry *ce = active_cache[i];
 401                 char *name;
 402                 int kept;
 403                 if (!S_ISREG(ce->ce_mode))
 404                         continue;
 405                 if (!pathspec_matches(paths, ce->name))
 406                         continue;
 407                 name = ce->name;
 408                 if (name[0] == '-') {
 409                         int len = ce_namelen(ce);
 410                         name = xmalloc(len + 3);
 411                         memcpy(name, "./", 2);
 412                         memcpy(name + 2, ce->name, len + 1);
 413                 }
 414                 argv[argc++] = name;
 415                 if (MAXARGS <= argc) {
 416                         status = flush_grep(opt, argc, nr, argv, &kept);
 417                         if (0 < status)
 418                                 hit = 1;
 419                         argc = nr + kept;
 420                 }
 421                 if (ce_stage(ce)) {
 422                         do {
 423                                 i++;
 424                         } while (i < active_nr &&
 425                                  !strcmp(ce->name, active_cache[i]->name));
 426                         i--; /* compensate for loop control */
 427                 }
 428         }
 429         if (argc > nr) {
 430                 status = flush_grep(opt, argc, nr, argv, NULL);
 431                 if (0 < status)
 432                         hit = 1;
 433         }
 434         return hit;
 435 }
 436 #endif
 437
 438 static int grep_cache(struct grep_opt *opt, const char **paths, int cached)
 439 {
 440         int hit = 0;
 441         int nr;
 442         read_cache();
 443
 444 #if !NO_EXTERNAL_GREP
 445         /*
 446          * Use the external "grep" command for the case where
 447          * we grep through the checked-out files. It tends to
 448          * be a lot more optimized
 449          */
 450         if (!cached && !builtin_grep) {
 451                 hit = external_grep(opt, paths, cached);
 452                 if (hit >= 0)
 453                         return hit;
 454         }
 455 #endif
 456
 457         for (nr = 0; nr < active_nr; nr++) {
 458                 struct cache_entry *ce = active_cache[nr];
 459                 if (!S_ISREG(ce->ce_mode))
 460                         continue;
 461                 if (!pathspec_matches(paths, ce->name))
 462                         continue;
 463                 /*
 464                  * If CE_VALID is on, we assume worktree file and its cache entry
 465                  * are identical, even if worktree file has been modified, so use
 466                  * cache version instead
 467                  */
 468                 if (cached || (ce->ce_flags & CE_VALID)) {
 469                         if (ce_stage(ce))
 470                                 continue;
 471                         hit |= grep_sha1(opt, ce->sha1, ce->name, 0);
 472                 }
 473                 else
 474                         hit |= grep_file(opt, ce->name);
 475                 if (ce_stage(ce)) {
 476                         do {
 477                                 nr++;
 478                         } while (nr < active_nr &&
 479                                  !strcmp(ce->name, active_cache[nr]->name));
 480                         nr--; /* compensate for loop control */
 481                 }
 482         }
 483         free_grep_patterns(opt);
 484         return hit;
 485 }
 486
 487 static int grep_tree(struct grep_opt *opt, const char **paths,
 488                      struct tree_desc *tree,
 489                      const char *tree_name, const char *base)
 490 {
 491         int len;
 492         int hit = 0;
 493         struct name_entry entry;
 494         char *down;
 495         int tn_len = strlen(tree_name);
 496         struct strbuf pathbuf;
 497
 498         strbuf_init(&pathbuf, PATH_MAX + tn_len);
 499
 500         if (tn_len) {
 501                 strbuf_add(&pathbuf, tree_name, tn_len);
 502                 strbuf_addch(&pathbuf, ':');
 503                 tn_len = pathbuf.len;
 504         }
 505         strbuf_addstr(&pathbuf, base);
 506         len = pathbuf.len;
 507
 508         while (tree_entry(tree, &entry)) {
 509                 int te_len = tree_entry_len(entry.path, entry.sha1);
 510                 pathbuf.len = len;
 511                 strbuf_add(&pathbuf, entry.path, te_len);
 512
 513                 if (S_ISDIR(entry.mode))
 514                         /* Match "abc/" against pathspec to
 515                          * decide if we want to descend into "abc"
 516                          * directory.
 517                          */
 518                         strbuf_addch(&pathbuf, '/');
 519
 520                 down = pathbuf.buf + tn_len;
 521                 if (!pathspec_matches(paths, down))
 522                         ;
 523                 else if (S_ISREG(entry.mode))
 524                         hit |= grep_sha1(opt, entry.sha1, pathbuf.buf, tn_len);
 525                 else if (S_ISDIR(entry.mode)) {
 526                         enum object_type type;
 527                         struct tree_desc sub;
 528                         void *data;
 529                         unsigned long size;
 530
 531                         data = read_sha1_file(entry.sha1, &type, &size);
 532                         if (!data)
 533                                 die("unable to read tree (%s)",
 534                                     sha1_to_hex(entry.sha1));
 535                         init_tree_desc(&sub, data, size);
 536                         hit |= grep_tree(opt, paths, &sub, tree_name, down);
 537                         free(data);
 538                 }
 539         }
 540         strbuf_release(&pathbuf);
 541         return hit;
 542 }
 543
 544 static int grep_object(struct grep_opt *opt, const char **paths,
 545                        struct object *obj, const char *name)
 546 {
 547         if (obj->type == OBJ_BLOB)
 548                 return grep_sha1(opt, obj->sha1, name, 0);
 549         if (obj->type == OBJ_COMMIT || obj->type == OBJ_TREE) {
 550                 struct tree_desc tree;
 551                 void *data;
 552                 unsigned long size;
 553                 int hit;
 554                 data = read_object_with_reference(obj->sha1, tree_type,
 555                                                   &size, NULL);
 556                 if (!data)
 557                         die("unable to read tree (%s)", sha1_to_hex(obj->sha1));
 558                 init_tree_desc(&tree, data, size);
 559                 hit = grep_tree(opt, paths, &tree, name, "");
 560                 free(data);
 561                 return hit;
 562         }
 563         die("unable to grep from object of type %s", typename(obj->type));
 564 }
 565
 566 static const char builtin_grep_usage[] =
 567 "git grep <option>* [-e] <pattern> <rev>* [[--] <path>...]";
 568
 569 static const char emsg_invalid_context_len[] =
 570 "%s: invalid context length argument";
 571 static const char emsg_missing_context_len[] =
 572 "missing context length argument";
 573 static const char emsg_missing_argument[] =
 574 "option requires an argument -%s";
 575
 576 int cmd_grep(int argc, const char **argv, const char *prefix)
 577 {
 578         int hit = 0;
 579         int cached = 0;
 580         int seen_dashdash = 0;
 581         struct grep_opt opt;
 582         struct object_array list = { 0, 0, NULL };
 583         const char **paths = NULL;
 584         int i;
 585
 586         memset(&opt, 0, sizeof(opt));
 587         opt.prefix_length = (prefix && *prefix) ? strlen(prefix) : 0;
 588         opt.relative = 1;
 589         opt.pathname = 1;
 590         opt.pattern_tail = &opt.pattern_list;
 591         opt.regflags = REG_NEWLINE;
 592
 593         strcpy(opt.color_match, GIT_COLOR_RED GIT_COLOR_BOLD);
 594         opt.color = -1;
 595         git_config(grep_config, &opt);
 596         if (opt.color == -1)
 597                 opt.color = git_use_color_default;
 598
 599         /*
 600          * If there is no -- then the paths must exist in the working
 601          * tree.  If there is no explicit pattern specified with -e or
 602          * -f, we take the first unrecognized non option to be the
 603          * pattern, but then what follows it must be zero or more
 604          * valid refs up to the -- (if exists), and then existing
 605          * paths.  If there is an explicit pattern, then the first
 606          * unrecognized non option is the beginning of the refs list
 607          * that continues up to the -- (if exists), and then paths.
 608          */
 609
 610         while (1 < argc) {
 611                 const char *arg = argv[1];
 612                 argc--; argv++;
 613                 if (!strcmp("--cached", arg)) {
 614                         cached = 1;
 615                         continue;
 616                 }
 617                 if (!strcmp("--no-ext-grep", arg)) {
 618                         builtin_grep = 1;
 619                         continue;
 620                 }
 621                 if (!strcmp("-a", arg) ||
 622                     !strcmp("--text", arg)) {
 623                         opt.binary = GREP_BINARY_TEXT;
 624                         continue;
 625                 }
 626                 if (!strcmp("-i", arg) ||
 627                     !strcmp("--ignore-case", arg)) {
 628                         opt.regflags |= REG_ICASE;
 629                         continue;
 630                 }
 631                 if (!strcmp("-I", arg)) {
 632                         opt.binary = GREP_BINARY_NOMATCH;
 633                         continue;
 634                 }
 635                 if (!strcmp("-v", arg) ||
 636                     !strcmp("--invert-match", arg)) {
 637                         opt.invert = 1;
 638                         continue;
 639                 }
 640                 if (!strcmp("-E", arg) ||
 641                     !strcmp("--extended-regexp", arg)) {
 642                         opt.regflags |= REG_EXTENDED;
 643                         continue;
 644                 }
 645                 if (!strcmp("-F", arg) ||
 646                     !strcmp("--fixed-strings", arg)) {
 647                         opt.fixed = 1;
 648                         continue;
 649                 }
 650                 if (!strcmp("-G", arg) ||
 651                     !strcmp("--basic-regexp", arg)) {
 652                         opt.regflags &= ~REG_EXTENDED;
 653                         continue;
 654                 }
 655                 if (!strcmp("-n", arg)) {
 656                         opt.linenum = 1;
 657                         continue;
 658                 }
 659                 if (!strcmp("-h", arg)) {
 660                         opt.pathname = 0;
 661                         continue;
 662                 }
 663                 if (!strcmp("-H", arg)) {
 664                         opt.pathname = 1;
 665                         continue;
 666                 }
 667                 if (!strcmp("-l", arg) ||
 668                     !strcmp("--name-only", arg) ||
 669                     !strcmp("--files-with-matches", arg)) {
 670                         opt.name_only = 1;
 671                         continue;
 672                 }
 673                 if (!strcmp("-L", arg) ||
 674                     !strcmp("--files-without-match", arg)) {
 675                         opt.unmatch_name_only = 1;
 676                         continue;
 677                 }
 678                 if (!strcmp("-z", arg) ||
 679                     !strcmp("--null", arg)) {
 680                         opt.null_following_name = 1;
 681                         continue;
 682                 }
 683                 if (!strcmp("-c", arg) ||
 684                     !strcmp("--count", arg)) {
 685                         opt.count = 1;
 686                         continue;
 687                 }
 688                 if (!strcmp("-w", arg) ||
 689                     !strcmp("--word-regexp", arg)) {
 690                         opt.word_regexp = 1;
 691                         continue;
 692                 }
 693                 if (!prefixcmp(arg, "-A") ||
 694                     !prefixcmp(arg, "-B") ||
 695                     !prefixcmp(arg, "-C") ||
 696                     (arg[0] == '-' && '1' <= arg[1] && arg[1] <= '9')) {
 697                         unsigned num;
 698                         const char *scan;
 699                         switch (arg[1]) {
 700                         case 'A': case 'B': case 'C':
 701                                 if (!arg[2]) {
 702                                         if (argc <= 1)
 703                                                 die(emsg_missing_context_len);
 704                                         scan = *++argv;
 705                                         argc--;
 706                                 }
 707                                 else
 708                                         scan = arg + 2;
 709                                 break;
 710                         default:
 711                                 scan = arg + 1;
 712                                 break;
 713                         }
 714                         if (strtoul_ui(scan, 10, &num))
 715                                 die(emsg_invalid_context_len, scan);
 716                         switch (arg[1]) {
 717                         case 'A':
 718                                 opt.post_context = num;
 719                                 break;
 720                         default:
 721                         case 'C':
 722                                 opt.post_context = num;
 723                         case 'B':
 724                                 opt.pre_context = num;
 725                                 break;
 726                         }
 727                         continue;
 728                 }
 729                 if (!strcmp("-f", arg)) {
 730                         FILE *patterns;
 731                         int lno = 0;
 732                         char buf[1024];
 733                         if (argc <= 1)
 734                                 die(emsg_missing_argument, arg);
 735                         patterns = fopen(argv[1], "r");
 736                         if (!patterns)
 737                                 die("'%s': %s", argv[1], strerror(errno));
 738                         while (fgets(buf, sizeof(buf), patterns)) {
 739                                 int len = strlen(buf);
 740                                 if (len && buf[len-1] == '\n')
 741                                         buf[len-1] = 0;
 742                                 /* ignore empty line like grep does */
 743                                 if (!buf[0])
 744                                         continue;
 745                                 append_grep_pattern(&opt, xstrdup(buf),
 746                                                     argv[1], ++lno,
 747                                                     GREP_PATTERN);
 748                         }
 749                         fclose(patterns);
 750                         argv++;
 751                         argc--;
 752                         continue;
 753                 }
 754                 if (!strcmp("--not", arg)) {
 755                         append_grep_pattern(&opt, arg, "command line", 0,
 756                                             GREP_NOT);
 757                         continue;
 758                 }
 759                 if (!strcmp("--and", arg)) {
 760                         append_grep_pattern(&opt, arg, "command line", 0,
 761                                             GREP_AND);
 762                         continue;
 763                 }
 764                 if (!strcmp("--or", arg))
 765                         continue; /* no-op */
 766                 if (!strcmp("(", arg)) {
 767                         append_grep_pattern(&opt, arg, "command line", 0,
 768                                             GREP_OPEN_PAREN);
 769                         continue;
 770                 }
 771                 if (!strcmp(")", arg)) {
 772                         append_grep_pattern(&opt, arg, "command line", 0,
 773                                             GREP_CLOSE_PAREN);
 774                         continue;
 775                 }
 776                 if (!strcmp("--all-match", arg)) {
 777                         opt.all_match = 1;
 778                         continue;
 779                 }
 780                 if (!strcmp("-e", arg)) {
 781                         if (1 < argc) {
 782                                 append_grep_pattern(&opt, argv[1],
 783                                                     "-e option", 0,
 784                                                     GREP_PATTERN);
 785                                 argv++;
 786                                 argc--;
 787                                 continue;
 788                         }
 789                         die(emsg_missing_argument, arg);
 790                 }
 791                 if (!strcmp("--full-name", arg)) {
 792                         opt.relative = 0;
 793                         continue;
 794                 }
 795                 if (!strcmp("--color", arg)) {
 796                         opt.color = 1;
 797                         continue;
 798                 }
 799                 if (!strcmp("--no-color", arg)) {
 800                         opt.color = 0;
 801                         continue;
 802                 }
 803                 if (!strcmp("--", arg)) {
 804                         /* later processing wants to have this at argv[1] */
 805                         argv--;
 806                         argc++;
 807                         break;
 808                 }
 809                 if (*arg == '-')
 810                         usage(builtin_grep_usage);
 811
 812                 /* First unrecognized non-option token */
 813                 if (!opt.pattern_list) {
 814                         append_grep_pattern(&opt, arg, "command line", 0,
 815                                             GREP_PATTERN);
 816                         break;
 817                 }
 818                 else {
 819                         /* We are looking at the first path or rev;
 820                          * it is found at argv[1] after leaving the
 821                          * loop.
 822                          */
 823                         argc++; argv--;
 824                         break;
 825                 }
 826         }
 827
 828         if (opt.color && !opt.color_external)
 829                 builtin_grep = 1;
 830         if (!opt.pattern_list)
 831                 die("no pattern given.");
 832         if ((opt.regflags != REG_NEWLINE) && opt.fixed)
 833                 die("cannot mix --fixed-strings and regexp");
 834         compile_grep_patterns(&opt);
 835
 836         /* Check revs and then paths */
 837         for (i = 1; i < argc; i++) {
 838                 const char *arg = argv[i];
 839                 unsigned char sha1[20];
 840                 /* Is it a rev? */
 841                 if (!get_sha1(arg, sha1)) {
 842                         struct object *object = parse_object(sha1);
 843                         if (!object)
 844                                 die("bad object %s", arg);
 845                         add_object_array(object, arg, &list);
 846                         continue;
 847                 }
 848                 if (!strcmp(arg, "--")) {
 849                         i++;
 850                         seen_dashdash = 1;
 851                 }
 852                 break;
 853         }
 854
 855         /* The rest are paths */
 856         if (!seen_dashdash) {
 857                 int j;
 858                 for (j = i; j < argc; j++)
 859                         verify_filename(prefix, argv[j]);
 860         }
 861
 862         if (i < argc) {
 863                 paths = get_pathspec(prefix, argv + i);
 864                 if (opt.prefix_length && opt.relative) {
 865                         /* Make sure we do not get outside of paths */
 866                         for (i = 0; paths[i]; i++)
 867                                 if (strncmp(prefix, paths[i], opt.prefix_length))
 868                                         die("git grep: cannot generate relative filenames containing '..'");
 869                 }
 870         }
 871         else if (prefix) {
 872                 paths = xcalloc(2, sizeof(const char *));
 873                 paths[0] = prefix;
 874                 paths[1] = NULL;
 875         }
 876
 877         if (!list.nr) {
 878                 if (!cached)
 879                         setup_work_tree();
 880                 return !grep_cache(&opt, paths, cached);
 881         }
 882
 883         if (cached)
 884                 die("both --cached and trees are given.");
 885
 886         for (i = 0; i < list.nr; i++) {
 887                 struct object *real_obj;
 888                 real_obj = deref_tag(list.objects[i].item, NULL, 0);
 889                 if (grep_object(&opt, paths, real_obj, list.objects[i].name))
 890                         hit = 1;
 891         }
 892         free_grep_patterns(&opt);
 893         return !hit;
 894 }