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 <regex.h>
  14 #include <fnmatch.h>
  15 #include <sys/wait.h>
  16
  17 /*
  18  * git grep pathspecs are somewhat different from diff-tree pathspecs;
  19  * pathname wildcards are allowed.
  20  */
  21 static int pathspec_matches(const char **paths, const char *name)
  22 {
  23         int namelen, i;
  24         if (!paths || !*paths)
  25                 return 1;
  26         namelen = strlen(name);
  27         for (i = 0; paths[i]; i++) {
  28                 const char *match = paths[i];
  29                 int matchlen = strlen(match);
  30                 const char *cp, *meta;
  31
  32                 if (!matchlen ||
  33                     ((matchlen <= namelen) &&
  34                      !strncmp(name, match, matchlen) &&
  35                      (match[matchlen-1] == '/' ||
  36                       name[matchlen] == '\0' || name[matchlen] == '/')))
  37                         return 1;
  38                 if (!fnmatch(match, name, 0))
  39                         return 1;
  40                 if (name[namelen-1] != '/')
  41                         continue;
  42
  43                 /* We are being asked if the directory ("name") is worth
  44                  * descending into.
  45                  *
  46                  * Find the longest leading directory name that does
  47                  * not have metacharacter in the pathspec; the name
  48                  * we are looking at must overlap with that directory.
  49                  */
  50                 for (cp = match, meta = NULL; cp - match < matchlen; cp++) {
  51                         char ch = *cp;
  52                         if (ch == '*' || ch == '[' || ch == '?') {
  53                                 meta = cp;
  54                                 break;
  55                         }
  56                 }
  57                 if (!meta)
  58                         meta = cp; /* fully literal */
  59
  60                 if (namelen <= meta - match) {
  61                         /* Looking at "Documentation/" and
  62                          * the pattern says "Documentation/howto/", or
  63                          * "Documentation/diff*.txt".  The name we
  64                          * have should match prefix.
  65                          */
  66                         if (!memcmp(match, name, namelen))
  67                                 return 1;
  68                         continue;
  69                 }
  70
  71                 if (meta - match < namelen) {
  72                         /* Looking at "Documentation/howto/" and
  73                          * the pattern says "Documentation/h*";
  74                          * match up to "Do.../h"; this avoids descending
  75                          * into "Documentation/technical/".
  76                          */
  77                         if (!memcmp(match, name, meta - match))
  78                                 return 1;
  79                         continue;
  80                 }
  81         }
  82         return 0;
  83 }
  84
  85 enum grep_pat_token {
  86         GREP_PATTERN,
  87         GREP_AND,
  88         GREP_OPEN_PAREN,
  89         GREP_CLOSE_PAREN,
  90         GREP_NOT,
  91         GREP_OR,
  92 };
  93
  94 struct grep_pat {
  95         struct grep_pat *next;
  96         const char *origin;
  97         int no;
  98         enum grep_pat_token token;
  99         const char *pattern;
 100         regex_t regexp;
 101 };
 102
 103 enum grep_expr_node {
 104         GREP_NODE_ATOM,
 105         GREP_NODE_NOT,
 106         GREP_NODE_AND,
 107         GREP_NODE_OR,
 108 };
 109
 110 struct grep_expr {
 111         enum grep_expr_node node;
 112         union {
 113                 struct grep_pat *atom;
 114                 struct grep_expr *unary;
 115                 struct {
 116                         struct grep_expr *left;
 117                         struct grep_expr *right;
 118                 } binary;
 119         } u;
 120 };
 121
 122 struct grep_opt {
 123         struct grep_pat *pattern_list;
 124         struct grep_pat **pattern_tail;
 125         struct grep_expr *pattern_expression;
 126         int prefix_length;
 127         regex_t regexp;
 128         unsigned linenum:1;
 129         unsigned invert:1;
 130         unsigned name_only:1;
 131         unsigned unmatch_name_only:1;
 132         unsigned count:1;
 133         unsigned word_regexp:1;
 134         unsigned fixed:1;
 135 #define GREP_BINARY_DEFAULT     0
 136 #define GREP_BINARY_NOMATCH     1
 137 #define GREP_BINARY_TEXT        2
 138         unsigned binary:2;
 139         unsigned extended:1;
 140         unsigned relative:1;
 141         int regflags;
 142         unsigned pre_context;
 143         unsigned post_context;
 144 };
 145
 146 static void add_pattern(struct grep_opt *opt, const char *pat,
 147                         const char *origin, int no, enum grep_pat_token t)
 148 {
 149         struct grep_pat *p = xcalloc(1, sizeof(*p));
 150         p->pattern = pat;
 151         p->origin = origin;
 152         p->no = no;
 153         p->token = t;
 154         *opt->pattern_tail = p;
 155         opt->pattern_tail = &p->next;
 156         p->next = NULL;
 157 }
 158
 159 static void compile_regexp(struct grep_pat *p, struct grep_opt *opt)
 160 {
 161         int err = regcomp(&p->regexp, p->pattern, opt->regflags);
 162         if (err) {
 163                 char errbuf[1024];
 164                 char where[1024];
 165                 if (p->no)
 166                         sprintf(where, "In '%s' at %d, ",
 167                                 p->origin, p->no);
 168                 else if (p->origin)
 169                         sprintf(where, "%s, ", p->origin);
 170                 else
 171                         where[0] = 0;
 172                 regerror(err, &p->regexp, errbuf, 1024);
 173                 regfree(&p->regexp);
 174                 die("%s'%s': %s", where, p->pattern, errbuf);
 175         }
 176 }
 177
 178 static struct grep_expr *compile_pattern_expr(struct grep_pat **);
 179 static struct grep_expr *compile_pattern_atom(struct grep_pat **list)
 180 {
 181         struct grep_pat *p;
 182         struct grep_expr *x;
 183
 184         p = *list;
 185         switch (p->token) {
 186         case GREP_PATTERN: /* atom */
 187                 x = xcalloc(1, sizeof (struct grep_expr));
 188                 x->node = GREP_NODE_ATOM;
 189                 x->u.atom = p;
 190                 *list = p->next;
 191                 return x;
 192         case GREP_OPEN_PAREN:
 193                 *list = p->next;
 194                 x = compile_pattern_expr(list);
 195                 if (!x)
 196                         return NULL;
 197                 if (!*list || (*list)->token != GREP_CLOSE_PAREN)
 198                         die("unmatched parenthesis");
 199                 *list = (*list)->next;
 200                 return x;
 201         default:
 202                 return NULL;
 203         }
 204 }
 205
 206 static struct grep_expr *compile_pattern_not(struct grep_pat **list)
 207 {
 208         struct grep_pat *p;
 209         struct grep_expr *x;
 210
 211         p = *list;
 212         switch (p->token) {
 213         case GREP_NOT:
 214                 if (!p->next)
 215                         die("--not not followed by pattern expression");
 216                 *list = p->next;
 217                 x = xcalloc(1, sizeof (struct grep_expr));
 218                 x->node = GREP_NODE_NOT;
 219                 x->u.unary = compile_pattern_not(list);
 220                 if (!x->u.unary)
 221                         die("--not followed by non pattern expression");
 222                 return x;
 223         default:
 224                 return compile_pattern_atom(list);
 225         }
 226 }
 227
 228 static struct grep_expr *compile_pattern_and(struct grep_pat **list)
 229 {
 230         struct grep_pat *p;
 231         struct grep_expr *x, *y, *z;
 232
 233         x = compile_pattern_not(list);
 234         p = *list;
 235         if (p && p->token == GREP_AND) {
 236                 if (!p->next)
 237                         die("--and not followed by pattern expression");
 238                 *list = p->next;
 239                 y = compile_pattern_and(list);
 240                 if (!y)
 241                         die("--and not followed by pattern expression");
 242                 z = xcalloc(1, sizeof (struct grep_expr));
 243                 z->node = GREP_NODE_AND;
 244                 z->u.binary.left = x;
 245                 z->u.binary.right = y;
 246                 return z;
 247         }
 248         return x;
 249 }
 250
 251 static struct grep_expr *compile_pattern_or(struct grep_pat **list)
 252 {
 253         struct grep_pat *p;
 254         struct grep_expr *x, *y, *z;
 255
 256         x = compile_pattern_and(list);
 257         p = *list;
 258         if (x && p && p->token != GREP_CLOSE_PAREN) {
 259                 y = compile_pattern_or(list);
 260                 if (!y)
 261                         die("not a pattern expression %s", p->pattern);
 262                 z = xcalloc(1, sizeof (struct grep_expr));
 263                 z->node = GREP_NODE_OR;
 264                 z->u.binary.left = x;
 265                 z->u.binary.right = y;
 266                 return z;
 267         }
 268         return x;
 269 }
 270
 271 static struct grep_expr *compile_pattern_expr(struct grep_pat **list)
 272 {
 273         return compile_pattern_or(list);
 274 }
 275
 276 static void compile_patterns(struct grep_opt *opt)
 277 {
 278         struct grep_pat *p;
 279
 280         /* First compile regexps */
 281         for (p = opt->pattern_list; p; p = p->next) {
 282                 if (p->token == GREP_PATTERN)
 283                         compile_regexp(p, opt);
 284                 else
 285                         opt->extended = 1;
 286         }
 287
 288         if (!opt->extended)
 289                 return;
 290
 291         /* Then bundle them up in an expression.
 292          * A classic recursive descent parser would do.
 293          */
 294         p = opt->pattern_list;
 295         opt->pattern_expression = compile_pattern_expr(&p);
 296 #if DEBUG
 297         dump_pattern_exp(opt->pattern_expression, 0);
 298 #endif
 299         if (p)
 300                 die("incomplete pattern expression: %s", p->pattern);
 301 }
 302
 303 static char *end_of_line(char *cp, unsigned long *left)
 304 {
 305         unsigned long l = *left;
 306         while (l && *cp != '\n') {
 307                 l--;
 308                 cp++;
 309         }
 310         *left = l;
 311         return cp;
 312 }
 313
 314 static int word_char(char ch)
 315 {
 316         return isalnum(ch) || ch == '_';
 317 }
 318
 319 static void show_line(struct grep_opt *opt, const char *bol, const char *eol,
 320                       const char *name, unsigned lno, char sign)
 321 {
 322         printf("%s%c", name, sign);
 323         if (opt->linenum)
 324                 printf("%d%c", lno, sign);
 325         printf("%.*s\n", (int)(eol-bol), bol);
 326 }
 327
 328 /*
 329  * NEEDSWORK: share code with diff.c
 330  */
 331 #define FIRST_FEW_BYTES 8000
 332 static int buffer_is_binary(const char *ptr, unsigned long size)
 333 {
 334         if (FIRST_FEW_BYTES < size)
 335                 size = FIRST_FEW_BYTES;
 336         return !!memchr(ptr, 0, size);
 337 }
 338
 339 static int fixmatch(const char *pattern, char *line, regmatch_t *match)
 340 {
 341         char *hit = strstr(line, pattern);
 342         if (!hit) {
 343                 match->rm_so = match->rm_eo = -1;
 344                 return REG_NOMATCH;
 345         }
 346         else {
 347                 match->rm_so = hit - line;
 348                 match->rm_eo = match->rm_so + strlen(pattern);
 349                 return 0;
 350         }
 351 }
 352
 353 static int match_one_pattern(struct grep_opt *opt, struct grep_pat *p, char *bol, char *eol)
 354 {
 355         int hit = 0;
 356         int at_true_bol = 1;
 357         regmatch_t pmatch[10];
 358
 359  again:
 360         if (!opt->fixed) {
 361                 regex_t *exp = &p->regexp;
 362                 hit = !regexec(exp, bol, ARRAY_SIZE(pmatch),
 363                                pmatch, 0);
 364         }
 365         else {
 366                 hit = !fixmatch(p->pattern, bol, pmatch);
 367         }
 368
 369         if (hit && opt->word_regexp) {
 370                 if ((pmatch[0].rm_so < 0) ||
 371                     (eol - bol) <= pmatch[0].rm_so ||
 372                     (pmatch[0].rm_eo < 0) ||
 373                     (eol - bol) < pmatch[0].rm_eo)
 374                         die("regexp returned nonsense");
 375
 376                 /* Match beginning must be either beginning of the
 377                  * line, or at word boundary (i.e. the last char must
 378                  * not be a word char).  Similarly, match end must be
 379                  * either end of the line, or at word boundary
 380                  * (i.e. the next char must not be a word char).
 381                  */
 382                 if ( ((pmatch[0].rm_so == 0 && at_true_bol) ||
 383                       !word_char(bol[pmatch[0].rm_so-1])) &&
 384                      ((pmatch[0].rm_eo == (eol-bol)) ||
 385                       !word_char(bol[pmatch[0].rm_eo])) )
 386                         ;
 387                 else
 388                         hit = 0;
 389
 390                 if (!hit && pmatch[0].rm_so + bol + 1 < eol) {
 391                         /* There could be more than one match on the
 392                          * line, and the first match might not be
 393                          * strict word match.  But later ones could be!
 394                          */
 395                         bol = pmatch[0].rm_so + bol + 1;
 396                         at_true_bol = 0;
 397                         goto again;
 398                 }
 399         }
 400         return hit;
 401 }
 402
 403 static int match_expr_eval(struct grep_opt *opt,
 404                            struct grep_expr *x,
 405                            char *bol, char *eol)
 406 {
 407         switch (x->node) {
 408         case GREP_NODE_ATOM:
 409                 return match_one_pattern(opt, x->u.atom, bol, eol);
 410                 break;
 411         case GREP_NODE_NOT:
 412                 return !match_expr_eval(opt, x->u.unary, bol, eol);
 413         case GREP_NODE_AND:
 414                 return (match_expr_eval(opt, x->u.binary.left, bol, eol) &&
 415                         match_expr_eval(opt, x->u.binary.right, bol, eol));
 416         case GREP_NODE_OR:
 417                 return (match_expr_eval(opt, x->u.binary.left, bol, eol) ||
 418                         match_expr_eval(opt, x->u.binary.right, bol, eol));
 419         }
 420         die("Unexpected node type (internal error) %d\n", x->node);
 421 }
 422
 423 static int match_expr(struct grep_opt *opt, char *bol, char *eol)
 424 {
 425         struct grep_expr *x = opt->pattern_expression;
 426         return match_expr_eval(opt, x, bol, eol);
 427 }
 428
 429 static int match_line(struct grep_opt *opt, char *bol, char *eol)
 430 {
 431         struct grep_pat *p;
 432         if (opt->extended)
 433                 return match_expr(opt, bol, eol);
 434         for (p = opt->pattern_list; p; p = p->next) {
 435                 if (match_one_pattern(opt, p, bol, eol))
 436                         return 1;
 437         }
 438         return 0;
 439 }
 440
 441 static int grep_buffer(struct grep_opt *opt, const char *name,
 442                        char *buf, unsigned long size)
 443 {
 444         char *bol = buf;
 445         unsigned long left = size;
 446         unsigned lno = 1;
 447         struct pre_context_line {
 448                 char *bol;
 449                 char *eol;
 450         } *prev = NULL, *pcl;
 451         unsigned last_hit = 0;
 452         unsigned last_shown = 0;
 453         int binary_match_only = 0;
 454         const char *hunk_mark = "";
 455         unsigned count = 0;
 456
 457         if (buffer_is_binary(buf, size)) {
 458                 switch (opt->binary) {
 459                 case GREP_BINARY_DEFAULT:
 460                         binary_match_only = 1;
 461                         break;
 462                 case GREP_BINARY_NOMATCH:
 463                         return 0; /* Assume unmatch */
 464                         break;
 465                 default:
 466                         break;
 467                 }
 468         }
 469
 470         if (opt->pre_context)
 471                 prev = xcalloc(opt->pre_context, sizeof(*prev));
 472         if (opt->pre_context || opt->post_context)
 473                 hunk_mark = "--\n";
 474
 475         while (left) {
 476                 char *eol, ch;
 477                 int hit = 0;
 478
 479                 eol = end_of_line(bol, &left);
 480                 ch = *eol;
 481                 *eol = 0;
 482
 483                 hit = match_line(opt, bol, eol);
 484
 485                 /* "grep -v -e foo -e bla" should list lines
 486                  * that do not have either, so inversion should
 487                  * be done outside.
 488                  */
 489                 if (opt->invert)
 490                         hit = !hit;
 491                 if (opt->unmatch_name_only) {
 492                         if (hit)
 493                                 return 0;
 494                         goto next_line;
 495                 }
 496                 if (hit) {
 497                         count++;
 498                         if (binary_match_only) {
 499                                 printf("Binary file %s matches\n", name);
 500                                 return 1;
 501                         }
 502                         if (opt->name_only) {
 503                                 printf("%s\n", name);
 504                                 return 1;
 505                         }
 506                         /* Hit at this line.  If we haven't shown the
 507                          * pre-context lines, we would need to show them.
 508                          * When asked to do "count", this still show
 509                          * the context which is nonsense, but the user
 510                          * deserves to get that ;-).
 511                          */
 512                         if (opt->pre_context) {
 513                                 unsigned from;
 514                                 if (opt->pre_context < lno)
 515                                         from = lno - opt->pre_context;
 516                                 else
 517                                         from = 1;
 518                                 if (from <= last_shown)
 519                                         from = last_shown + 1;
 520                                 if (last_shown && from != last_shown + 1)
 521                                         printf(hunk_mark);
 522                                 while (from < lno) {
 523                                         pcl = &prev[lno-from-1];
 524                                         show_line(opt, pcl->bol, pcl->eol,
 525                                                   name, from, '-');
 526                                         from++;
 527                                 }
 528                                 last_shown = lno-1;
 529                         }
 530                         if (last_shown && lno != last_shown + 1)
 531                                 printf(hunk_mark);
 532                         if (!opt->count)
 533                                 show_line(opt, bol, eol, name, lno, ':');
 534                         last_shown = last_hit = lno;
 535                 }
 536                 else if (last_hit &&
 537                          lno <= last_hit + opt->post_context) {
 538                         /* If the last hit is within the post context,
 539                          * we need to show this line.
 540                          */
 541                         if (last_shown && lno != last_shown + 1)
 542                                 printf(hunk_mark);
 543                         show_line(opt, bol, eol, name, lno, '-');
 544                         last_shown = lno;
 545                 }
 546                 if (opt->pre_context) {
 547                         memmove(prev+1, prev,
 548                                 (opt->pre_context-1) * sizeof(*prev));
 549                         prev->bol = bol;
 550                         prev->eol = eol;
 551                 }
 552
 553         next_line:
 554                 *eol = ch;
 555                 bol = eol + 1;
 556                 if (!left)
 557                         break;
 558                 left--;
 559                 lno++;
 560         }
 561
 562         if (opt->unmatch_name_only) {
 563                 /* We did not see any hit, so we want to show this */
 564                 printf("%s\n", name);
 565                 return 1;
 566         }
 567
 568         /* NEEDSWORK:
 569          * The real "grep -c foo *.c" gives many "bar.c:0" lines,
 570          * which feels mostly useless but sometimes useful.  Maybe
 571          * make it another option?  For now suppress them.
 572          */
 573         if (opt->count && count)
 574                 printf("%s:%u\n", name, count);
 575         return !!last_hit;
 576 }
 577
 578 static int grep_sha1(struct grep_opt *opt, const unsigned char *sha1, const char *name, int tree_name_len)
 579 {
 580         unsigned long size;
 581         char *data;
 582         char type[20];
 583         char *to_free = NULL;
 584         int hit;
 585
 586         data = read_sha1_file(sha1, type, &size);
 587         if (!data) {
 588                 error("'%s': unable to read %s", name, sha1_to_hex(sha1));
 589                 return 0;
 590         }
 591         if (opt->relative && opt->prefix_length) {
 592                 static char name_buf[PATH_MAX];
 593                 char *cp;
 594                 int name_len = strlen(name) - opt->prefix_length + 1;
 595
 596                 if (!tree_name_len)
 597                         name += opt->prefix_length;
 598                 else {
 599                         if (ARRAY_SIZE(name_buf) <= name_len)
 600                                 cp = to_free = xmalloc(name_len);
 601                         else
 602                                 cp = name_buf;
 603                         memcpy(cp, name, tree_name_len);
 604                         strcpy(cp + tree_name_len,
 605                                name + tree_name_len + opt->prefix_length);
 606                         name = cp;
 607                 }
 608         }
 609         hit = grep_buffer(opt, name, data, size);
 610         free(data);
 611         free(to_free);
 612         return hit;
 613 }
 614
 615 static int grep_file(struct grep_opt *opt, const char *filename)
 616 {
 617         struct stat st;
 618         int i;
 619         char *data;
 620         if (lstat(filename, &st) < 0) {
 621         err_ret:
 622                 if (errno != ENOENT)
 623                         error("'%s': %s", filename, strerror(errno));
 624                 return 0;
 625         }
 626         if (!st.st_size)
 627                 return 0; /* empty file -- no grep hit */
 628         if (!S_ISREG(st.st_mode))
 629                 return 0;
 630         i = open(filename, O_RDONLY);
 631         if (i < 0)
 632                 goto err_ret;
 633         data = xmalloc(st.st_size + 1);
 634         if (st.st_size != xread(i, data, st.st_size)) {
 635                 error("'%s': short read %s", filename, strerror(errno));
 636                 close(i);
 637                 free(data);
 638                 return 0;
 639         }
 640         close(i);
 641         if (opt->relative && opt->prefix_length)
 642                 filename += opt->prefix_length;
 643         i = grep_buffer(opt, filename, data, st.st_size);
 644         free(data);
 645         return i;
 646 }
 647
 648 static int exec_grep(int argc, const char **argv)
 649 {
 650         pid_t pid;
 651         int status;
 652
 653         argv[argc] = NULL;
 654         pid = fork();
 655         if (pid < 0)
 656                 return pid;
 657         if (!pid) {
 658                 execvp("grep", (char **) argv);
 659                 exit(255);
 660         }
 661         while (waitpid(pid, &status, 0) < 0) {
 662                 if (errno == EINTR)
 663                         continue;
 664                 return -1;
 665         }
 666         if (WIFEXITED(status)) {
 667                 if (!WEXITSTATUS(status))
 668                         return 1;
 669                 return 0;
 670         }
 671         return -1;
 672 }
 673
 674 #define MAXARGS 1000
 675 #define ARGBUF 4096
 676 #define push_arg(a) do { \
 677         if (nr < MAXARGS) argv[nr++] = (a); \
 678         else die("maximum number of args exceeded"); \
 679         } while (0)
 680
 681 static int external_grep(struct grep_opt *opt, const char **paths, int cached)
 682 {
 683         int i, nr, argc, hit, len, status;
 684         const char *argv[MAXARGS+1];
 685         char randarg[ARGBUF];
 686         char *argptr = randarg;
 687         struct grep_pat *p;
 688
 689         if (opt->extended || (opt->relative && opt->prefix_length))
 690                 return -1;
 691         len = nr = 0;
 692         push_arg("grep");
 693         if (opt->fixed)
 694                 push_arg("-F");
 695         if (opt->linenum)
 696                 push_arg("-n");
 697         if (opt->regflags & REG_EXTENDED)
 698                 push_arg("-E");
 699         if (opt->regflags & REG_ICASE)
 700                 push_arg("-i");
 701         if (opt->word_regexp)
 702                 push_arg("-w");
 703         if (opt->name_only)
 704                 push_arg("-l");
 705         if (opt->unmatch_name_only)
 706                 push_arg("-L");
 707         if (opt->count)
 708                 push_arg("-c");
 709         if (opt->post_context || opt->pre_context) {
 710                 if (opt->post_context != opt->pre_context) {
 711                         if (opt->pre_context) {
 712                                 push_arg("-B");
 713                                 len += snprintf(argptr, sizeof(randarg)-len,
 714                                                 "%u", opt->pre_context);
 715                                 if (sizeof(randarg) <= len)
 716                                         die("maximum length of args exceeded");
 717                                 push_arg(argptr);
 718                                 argptr += len;
 719                         }
 720                         if (opt->post_context) {
 721                                 push_arg("-A");
 722                                 len += snprintf(argptr, sizeof(randarg)-len,
 723                                                 "%u", opt->post_context);
 724                                 if (sizeof(randarg) <= len)
 725                                         die("maximum length of args exceeded");
 726                                 push_arg(argptr);
 727                                 argptr += len;
 728                         }
 729                 }
 730                 else {
 731                         push_arg("-C");
 732                         len += snprintf(argptr, sizeof(randarg)-len,
 733                                         "%u", opt->post_context);
 734                         if (sizeof(randarg) <= len)
 735                                 die("maximum length of args exceeded");
 736                         push_arg(argptr);
 737                         argptr += len;
 738                 }
 739         }
 740         for (p = opt->pattern_list; p; p = p->next) {
 741                 push_arg("-e");
 742                 push_arg(p->pattern);
 743         }
 744
 745         /*
 746          * To make sure we get the header printed out when we want it,
 747          * add /dev/null to the paths to grep.  This is unnecessary
 748          * (and wrong) with "-l" or "-L", which always print out the
 749          * name anyway.
 750          *
 751          * GNU grep has "-H", but this is portable.
 752          */
 753         if (!opt->name_only && !opt->unmatch_name_only)
 754                 push_arg("/dev/null");
 755
 756         hit = 0;
 757         argc = nr;
 758         for (i = 0; i < active_nr; i++) {
 759                 struct cache_entry *ce = active_cache[i];
 760                 char *name;
 761                 if (ce_stage(ce) || !S_ISREG(ntohl(ce->ce_mode)))
 762                         continue;
 763                 if (!pathspec_matches(paths, ce->name))
 764                         continue;
 765                 name = ce->name;
 766                 if (name[0] == '-') {
 767                         int len = ce_namelen(ce);
 768                         name = xmalloc(len + 3);
 769                         memcpy(name, "./", 2);
 770                         memcpy(name + 2, ce->name, len + 1);
 771                 }
 772                 argv[argc++] = name;
 773                 if (argc < MAXARGS)
 774                         continue;
 775                 status = exec_grep(argc, argv);
 776                 if (0 < status)
 777                         hit = 1;
 778                 argc = nr;
 779         }
 780         if (argc > nr) {
 781                 status = exec_grep(argc, argv);
 782                 if (0 < status)
 783                         hit = 1;
 784         }
 785         return hit;
 786 }
 787
 788 static int grep_cache(struct grep_opt *opt, const char **paths, int cached)
 789 {
 790         int hit = 0;
 791         int nr;
 792         read_cache();
 793
 794 #ifdef __unix__
 795         /*
 796          * Use the external "grep" command for the case where
 797          * we grep through the checked-out files. It tends to
 798          * be a lot more optimized
 799          */
 800         if (!cached) {
 801                 hit = external_grep(opt, paths, cached);
 802                 if (hit >= 0)
 803                         return hit;
 804         }
 805 #endif
 806
 807         for (nr = 0; nr < active_nr; nr++) {
 808                 struct cache_entry *ce = active_cache[nr];
 809                 if (ce_stage(ce) || !S_ISREG(ntohl(ce->ce_mode)))
 810                         continue;
 811                 if (!pathspec_matches(paths, ce->name))
 812                         continue;
 813                 if (cached)
 814                         hit |= grep_sha1(opt, ce->sha1, ce->name, 0);
 815                 else
 816                         hit |= grep_file(opt, ce->name);
 817         }
 818         return hit;
 819 }
 820
 821 static int grep_tree(struct grep_opt *opt, const char **paths,
 822                      struct tree_desc *tree,
 823                      const char *tree_name, const char *base)
 824 {
 825         int len;
 826         int hit = 0;
 827         struct name_entry entry;
 828         char *down;
 829         int tn_len = strlen(tree_name);
 830         char *path_buf = xmalloc(PATH_MAX + tn_len + 100);
 831
 832         if (tn_len) {
 833                 tn_len = sprintf(path_buf, "%s:", tree_name);
 834                 down = path_buf + tn_len;
 835                 strcat(down, base);
 836         }
 837         else {
 838                 down = path_buf;
 839                 strcpy(down, base);
 840         }
 841         len = strlen(path_buf);
 842
 843         while (tree_entry(tree, &entry)) {
 844                 strcpy(path_buf + len, entry.path);
 845
 846                 if (S_ISDIR(entry.mode))
 847                         /* Match "abc/" against pathspec to
 848                          * decide if we want to descend into "abc"
 849                          * directory.
 850                          */
 851                         strcpy(path_buf + len + entry.pathlen, "/");
 852
 853                 if (!pathspec_matches(paths, down))
 854                         ;
 855                 else if (S_ISREG(entry.mode))
 856                         hit |= grep_sha1(opt, entry.sha1, path_buf, tn_len);
 857                 else if (S_ISDIR(entry.mode)) {
 858                         char type[20];
 859                         struct tree_desc sub;
 860                         void *data;
 861                         data = read_sha1_file(entry.sha1, type, &sub.size);
 862                         if (!data)
 863                                 die("unable to read tree (%s)",
 864                                     sha1_to_hex(entry.sha1));
 865                         sub.buf = data;
 866                         hit |= grep_tree(opt, paths, &sub, tree_name, down);
 867                         free(data);
 868                 }
 869         }
 870         return hit;
 871 }
 872
 873 static int grep_object(struct grep_opt *opt, const char **paths,
 874                        struct object *obj, const char *name)
 875 {
 876         if (obj->type == OBJ_BLOB)
 877                 return grep_sha1(opt, obj->sha1, name, 0);
 878         if (obj->type == OBJ_COMMIT || obj->type == OBJ_TREE) {
 879                 struct tree_desc tree;
 880                 void *data;
 881                 int hit;
 882                 data = read_object_with_reference(obj->sha1, tree_type,
 883                                                   &tree.size, NULL);
 884                 if (!data)
 885                         die("unable to read tree (%s)", sha1_to_hex(obj->sha1));
 886                 tree.buf = data;
 887                 hit = grep_tree(opt, paths, &tree, name, "");
 888                 free(data);
 889                 return hit;
 890         }
 891         die("unable to grep from object of type %s", typename(obj->type));
 892 }
 893
 894 static const char builtin_grep_usage[] =
 895 "git-grep <option>* <rev>* [-e] <pattern> [<path>...]";
 896
 897 static const char emsg_invalid_context_len[] =
 898 "%s: invalid context length argument";
 899 static const char emsg_missing_context_len[] =
 900 "missing context length argument";
 901 static const char emsg_missing_argument[] =
 902 "option requires an argument -%s";
 903
 904 int cmd_grep(int argc, const char **argv, const char *prefix)
 905 {
 906         int hit = 0;
 907         int cached = 0;
 908         int seen_dashdash = 0;
 909         struct grep_opt opt;
 910         struct object_array list = { 0, 0, NULL };
 911         const char **paths = NULL;
 912         int i;
 913
 914         memset(&opt, 0, sizeof(opt));
 915         opt.prefix_length = (prefix && *prefix) ? strlen(prefix) : 0;
 916         opt.relative = 1;
 917         opt.pattern_tail = &opt.pattern_list;
 918         opt.regflags = REG_NEWLINE;
 919
 920         /*
 921          * If there is no -- then the paths must exist in the working
 922          * tree.  If there is no explicit pattern specified with -e or
 923          * -f, we take the first unrecognized non option to be the
 924          * pattern, but then what follows it must be zero or more
 925          * valid refs up to the -- (if exists), and then existing
 926          * paths.  If there is an explicit pattern, then the first
 927          * unrecognized non option is the beginning of the refs list
 928          * that continues up to the -- (if exists), and then paths.
 929          */
 930
 931         while (1 < argc) {
 932                 const char *arg = argv[1];
 933                 argc--; argv++;
 934                 if (!strcmp("--cached", arg)) {
 935                         cached = 1;
 936                         continue;
 937                 }
 938                 if (!strcmp("-a", arg) ||
 939                     !strcmp("--text", arg)) {
 940                         opt.binary = GREP_BINARY_TEXT;
 941                         continue;
 942                 }
 943                 if (!strcmp("-i", arg) ||
 944                     !strcmp("--ignore-case", arg)) {
 945                         opt.regflags |= REG_ICASE;
 946                         continue;
 947                 }
 948                 if (!strcmp("-I", arg)) {
 949                         opt.binary = GREP_BINARY_NOMATCH;
 950                         continue;
 951                 }
 952                 if (!strcmp("-v", arg) ||
 953                     !strcmp("--invert-match", arg)) {
 954                         opt.invert = 1;
 955                         continue;
 956                 }
 957                 if (!strcmp("-E", arg) ||
 958                     !strcmp("--extended-regexp", arg)) {
 959                         opt.regflags |= REG_EXTENDED;
 960                         continue;
 961                 }
 962                 if (!strcmp("-F", arg) ||
 963                     !strcmp("--fixed-strings", arg)) {
 964                         opt.fixed = 1;
 965                         continue;
 966                 }
 967                 if (!strcmp("-G", arg) ||
 968                     !strcmp("--basic-regexp", arg)) {
 969                         opt.regflags &= ~REG_EXTENDED;
 970                         continue;
 971                 }
 972                 if (!strcmp("-n", arg)) {
 973                         opt.linenum = 1;
 974                         continue;
 975                 }
 976                 if (!strcmp("-H", arg)) {
 977                         /* We always show the pathname, so this
 978                          * is a noop.
 979                          */
 980                         continue;
 981                 }
 982                 if (!strcmp("-l", arg) ||
 983                     !strcmp("--files-with-matches", arg)) {
 984                         opt.name_only = 1;
 985                         continue;
 986                 }
 987                 if (!strcmp("-L", arg) ||
 988                     !strcmp("--files-without-match", arg)) {
 989                         opt.unmatch_name_only = 1;
 990                         continue;
 991                 }
 992                 if (!strcmp("-c", arg) ||
 993                     !strcmp("--count", arg)) {
 994                         opt.count = 1;
 995                         continue;
 996                 }
 997                 if (!strcmp("-w", arg) ||
 998                     !strcmp("--word-regexp", arg)) {
 999                         opt.word_regexp = 1;
1000                         continue;
1001                 }
1002                 if (!strncmp("-A", arg, 2) ||
1003                     !strncmp("-B", arg, 2) ||
1004                     !strncmp("-C", arg, 2) ||
1005                     (arg[0] == '-' && '1' <= arg[1] && arg[1] <= '9')) {
1006                         unsigned num;
1007                         const char *scan;
1008                         switch (arg[1]) {
1009                         case 'A': case 'B': case 'C':
1010                                 if (!arg[2]) {
1011                                         if (argc <= 1)
1012                                                 die(emsg_missing_context_len);
1013                                         scan = *++argv;
1014                                         argc--;
1015                                 }
1016                                 else
1017                                         scan = arg + 2;
1018                                 break;
1019                         default:
1020                                 scan = arg + 1;
1021                                 break;
1022                         }
1023                         if (sscanf(scan, "%u", &num) != 1)
1024                                 die(emsg_invalid_context_len, scan);
1025                         switch (arg[1]) {
1026                         case 'A':
1027                                 opt.post_context = num;
1028                                 break;
1029                         default:
1030                         case 'C':
1031                                 opt.post_context = num;
1032                         case 'B':
1033                                 opt.pre_context = num;
1034                                 break;
1035                         }
1036                         continue;
1037                 }
1038                 if (!strcmp("-f", arg)) {
1039                         FILE *patterns;
1040                         int lno = 0;
1041                         char buf[1024];
1042                         if (argc <= 1)
1043                                 die(emsg_missing_argument, arg);
1044                         patterns = fopen(argv[1], "r");
1045                         if (!patterns)
1046                                 die("'%s': %s", argv[1], strerror(errno));
1047                         while (fgets(buf, sizeof(buf), patterns)) {
1048                                 int len = strlen(buf);
1049                                 if (buf[len-1] == '\n')
1050                                         buf[len-1] = 0;
1051                                 /* ignore empty line like grep does */
1052                                 if (!buf[0])
1053                                         continue;
1054                                 add_pattern(&opt, strdup(buf), argv[1], ++lno,
1055                                             GREP_PATTERN);
1056                         }
1057                         fclose(patterns);
1058                         argv++;
1059                         argc--;
1060                         continue;
1061                 }
1062                 if (!strcmp("--not", arg)) {
1063                         add_pattern(&opt, arg, "command line", 0, GREP_NOT);
1064                         continue;
1065                 }
1066                 if (!strcmp("--and", arg)) {
1067                         add_pattern(&opt, arg, "command line", 0, GREP_AND);
1068                         continue;
1069                 }
1070                 if (!strcmp("--or", arg))
1071                         continue; /* no-op */
1072                 if (!strcmp("(", arg)) {
1073                         add_pattern(&opt, arg, "command line", 0, GREP_OPEN_PAREN);
1074                         continue;
1075                 }
1076                 if (!strcmp(")", arg)) {
1077                         add_pattern(&opt, arg, "command line", 0, GREP_CLOSE_PAREN);
1078                         continue;
1079                 }
1080                 if (!strcmp("-e", arg)) {
1081                         if (1 < argc) {
1082                                 add_pattern(&opt, argv[1], "-e option", 0,
1083                                             GREP_PATTERN);
1084                                 argv++;
1085                                 argc--;
1086                                 continue;
1087                         }
1088                         die(emsg_missing_argument, arg);
1089                 }
1090                 if (!strcmp("--full-name", arg)) {
1091                         opt.relative = 0;
1092                         continue;
1093                 }
1094                 if (!strcmp("--", arg)) {
1095                         /* later processing wants to have this at argv[1] */
1096                         argv--;
1097                         argc++;
1098                         break;
1099                 }
1100                 if (*arg == '-')
1101                         usage(builtin_grep_usage);
1102
1103                 /* First unrecognized non-option token */
1104                 if (!opt.pattern_list) {
1105                         add_pattern(&opt, arg, "command line", 0,
1106                                     GREP_PATTERN);
1107                         break;
1108                 }
1109                 else {
1110                         /* We are looking at the first path or rev;
1111                          * it is found at argv[1] after leaving the
1112                          * loop.
1113                          */
1114                         argc++; argv--;
1115                         break;
1116                 }
1117         }
1118
1119         if (!opt.pattern_list)
1120                 die("no pattern given.");
1121         if ((opt.regflags != REG_NEWLINE) && opt.fixed)
1122                 die("cannot mix --fixed-strings and regexp");
1123         if (!opt.fixed)
1124                 compile_patterns(&opt);
1125
1126         /* Check revs and then paths */
1127         for (i = 1; i < argc; i++) {
1128                 const char *arg = argv[i];
1129                 unsigned char sha1[20];
1130                 /* Is it a rev? */
1131                 if (!get_sha1(arg, sha1)) {
1132                         struct object *object = parse_object(sha1);
1133                         if (!object)
1134                                 die("bad object %s", arg);
1135                         add_object_array(object, arg, &list);
1136                         continue;
1137                 }
1138                 if (!strcmp(arg, "--")) {
1139                         i++;
1140                         seen_dashdash = 1;
1141                 }
1142                 break;
1143         }
1144
1145         /* The rest are paths */
1146         if (!seen_dashdash) {
1147                 int j;
1148                 for (j = i; j < argc; j++)
1149                         verify_filename(prefix, argv[j]);
1150         }
1151
1152         if (i < argc) {
1153                 paths = get_pathspec(prefix, argv + i);
1154                 if (opt.prefix_length && opt.relative) {
1155                         /* Make sure we do not get outside of paths */
1156                         for (i = 0; paths[i]; i++)
1157                                 if (strncmp(prefix, paths[i], opt.prefix_length))
1158                                         die("git-grep: cannot generate relative filenames containing '..'");
1159                 }
1160         }
1161         else if (prefix) {
1162                 paths = xcalloc(2, sizeof(const char *));
1163                 paths[0] = prefix;
1164                 paths[1] = NULL;
1165         }
1166
1167         if (!list.nr)
1168                 return !grep_cache(&opt, paths, cached);
1169
1170         if (cached)
1171                 die("both --cached and trees are given.");
1172
1173         for (i = 0; i < list.nr; i++) {
1174                 struct object *real_obj;
1175                 real_obj = deref_tag(list.objects[i].item, NULL, 0);
1176                 if (grep_object(&opt, paths, real_obj, list.objects[i].name))
1177                         hit = 1;
1178         }
1179         return !hit;
1180 }