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         regex_t regexp;
 127         unsigned linenum:1;
 128         unsigned invert:1;
 129         unsigned name_only:1;
 130         unsigned unmatch_name_only:1;
 131         unsigned count:1;
 132         unsigned word_regexp:1;
 133         unsigned fixed:1;
 134 #define GREP_BINARY_DEFAULT     0
 135 #define GREP_BINARY_NOMATCH     1
 136 #define GREP_BINARY_TEXT        2
 137         unsigned binary:2;
 138         unsigned extended:1;
 139         int regflags;
 140         unsigned pre_context;
 141         unsigned post_context;
 142 };
 143
 144 static void add_pattern(struct grep_opt *opt, const char *pat,
 145                         const char *origin, int no, enum grep_pat_token t)
 146 {
 147         struct grep_pat *p = xcalloc(1, sizeof(*p));
 148         p->pattern = pat;
 149         p->origin = origin;
 150         p->no = no;
 151         p->token = t;
 152         *opt->pattern_tail = p;
 153         opt->pattern_tail = &p->next;
 154         p->next = NULL;
 155 }
 156
 157 static void compile_regexp(struct grep_pat *p, struct grep_opt *opt)
 158 {
 159         int err = regcomp(&p->regexp, p->pattern, opt->regflags);
 160         if (err) {
 161                 char errbuf[1024];
 162                 char where[1024];
 163                 if (p->no)
 164                         sprintf(where, "In '%s' at %d, ",
 165                                 p->origin, p->no);
 166                 else if (p->origin)
 167                         sprintf(where, "%s, ", p->origin);
 168                 else
 169                         where[0] = 0;
 170                 regerror(err, &p->regexp, errbuf, 1024);
 171                 regfree(&p->regexp);
 172                 die("%s'%s': %s", where, p->pattern, errbuf);
 173         }
 174 }
 175
 176 #if DEBUG
 177 static inline void indent(int in)
 178 {
 179         int i;
 180         for (i = 0; i < in; i++) putchar(' ');
 181 }
 182
 183 static void dump_pattern_exp(struct grep_expr *x, int in)
 184 {
 185         switch (x->node) {
 186         case GREP_NODE_ATOM:
 187                 indent(in);
 188                 puts(x->u.atom->pattern);
 189                 break;
 190         case GREP_NODE_NOT:
 191                 indent(in);
 192                 puts("--not");
 193                 dump_pattern_exp(x->u.unary, in+1);
 194                 break;
 195         case GREP_NODE_AND:
 196                 dump_pattern_exp(x->u.binary.left, in+1);
 197                 indent(in);
 198                 puts("--and");
 199                 dump_pattern_exp(x->u.binary.right, in+1);
 200                 break;
 201         case GREP_NODE_OR:
 202                 dump_pattern_exp(x->u.binary.left, in+1);
 203                 indent(in);
 204                 puts("--or");
 205                 dump_pattern_exp(x->u.binary.right, in+1);
 206                 break;
 207         }
 208 }
 209
 210 static void looking_at(const char *msg, struct grep_pat **list)
 211 {
 212         struct grep_pat *p = *list;
 213         fprintf(stderr, "%s: looking at ", msg);
 214         if (!p)
 215                 fprintf(stderr, "empty\n");
 216         else
 217                 fprintf(stderr, "<%s>\n", p->pattern);
 218 }
 219 #else
 220 #define looking_at(a,b) do {} while(0)
 221 #endif
 222
 223 static struct grep_expr *compile_pattern_expr(struct grep_pat **);
 224 static struct grep_expr *compile_pattern_atom(struct grep_pat **list)
 225 {
 226         struct grep_pat *p;
 227         struct grep_expr *x;
 228
 229         looking_at("atom", list);
 230
 231         p = *list;
 232         switch (p->token) {
 233         case GREP_PATTERN: /* atom */
 234                 x = xcalloc(1, sizeof (struct grep_expr));
 235                 x->node = GREP_NODE_ATOM;
 236                 x->u.atom = p;
 237                 *list = p->next;
 238                 return x;
 239         case GREP_OPEN_PAREN:
 240                 *list = p->next;
 241                 x = compile_pattern_expr(list);
 242                 if (!x)
 243                         return NULL;
 244                 if (!*list || (*list)->token != GREP_CLOSE_PAREN)
 245                         die("unmatched parenthesis");
 246                 *list = (*list)->next;
 247                 return x;
 248         default:
 249                 return NULL;
 250         }
 251 }
 252
 253 static struct grep_expr *compile_pattern_not(struct grep_pat **list)
 254 {
 255         struct grep_pat *p;
 256         struct grep_expr *x;
 257
 258         looking_at("not", list);
 259
 260         p = *list;
 261         switch (p->token) {
 262         case GREP_NOT:
 263                 if (!p->next)
 264                         die("--not not followed by pattern expression");
 265                 *list = p->next;
 266                 x = xcalloc(1, sizeof (struct grep_expr));
 267                 x->node = GREP_NODE_NOT;
 268                 x->u.unary = compile_pattern_not(list);
 269                 if (!x->u.unary)
 270                         die("--not followed by non pattern expression");
 271                 return x;
 272         default:
 273                 return compile_pattern_atom(list);
 274         }
 275 }
 276
 277 static struct grep_expr *compile_pattern_and(struct grep_pat **list)
 278 {
 279         struct grep_pat *p;
 280         struct grep_expr *x, *y, *z;
 281
 282         looking_at("and", list);
 283
 284         x = compile_pattern_not(list);
 285         p = *list;
 286         if (p && p->token == GREP_AND) {
 287                 if (!p->next)
 288                         die("--and not followed by pattern expression");
 289                 *list = p->next;
 290                 y = compile_pattern_and(list);
 291                 if (!y)
 292                         die("--and not followed by pattern expression");
 293                 z = xcalloc(1, sizeof (struct grep_expr));
 294                 z->node = GREP_NODE_AND;
 295                 z->u.binary.left = x;
 296                 z->u.binary.right = y;
 297                 return z;
 298         }
 299         return x;
 300 }
 301
 302 static struct grep_expr *compile_pattern_or(struct grep_pat **list)
 303 {
 304         struct grep_pat *p;
 305         struct grep_expr *x, *y, *z;
 306
 307         looking_at("or", list);
 308
 309         x = compile_pattern_and(list);
 310         p = *list;
 311         if (x && p && p->token != GREP_CLOSE_PAREN) {
 312                 y = compile_pattern_or(list);
 313                 if (!y)
 314                         die("not a pattern expression %s", p->pattern);
 315                 z = xcalloc(1, sizeof (struct grep_expr));
 316                 z->node = GREP_NODE_OR;
 317                 z->u.binary.left = x;
 318                 z->u.binary.right = y;
 319                 return z;
 320         }
 321         return x;
 322 }
 323
 324 static struct grep_expr *compile_pattern_expr(struct grep_pat **list)
 325 {
 326         looking_at("expr", list);
 327
 328         return compile_pattern_or(list);
 329 }
 330
 331 static void compile_patterns(struct grep_opt *opt)
 332 {
 333         struct grep_pat *p;
 334
 335         /* First compile regexps */
 336         for (p = opt->pattern_list; p; p = p->next) {
 337                 if (p->token == GREP_PATTERN)
 338                         compile_regexp(p, opt);
 339                 else
 340                         opt->extended = 1;
 341         }
 342
 343         if (!opt->extended)
 344                 return;
 345
 346         /* Then bundle them up in an expression.
 347          * A classic recursive descent parser would do.
 348          */
 349         p = opt->pattern_list;
 350         opt->pattern_expression = compile_pattern_expr(&p);
 351 #if DEBUG
 352         dump_pattern_exp(opt->pattern_expression, 0);
 353 #endif
 354         if (p)
 355                 die("incomplete pattern expression: %s", p->pattern);
 356 }
 357
 358 static char *end_of_line(char *cp, unsigned long *left)
 359 {
 360         unsigned long l = *left;
 361         while (l && *cp != '\n') {
 362                 l--;
 363                 cp++;
 364         }
 365         *left = l;
 366         return cp;
 367 }
 368
 369 static int word_char(char ch)
 370 {
 371         return isalnum(ch) || ch == '_';
 372 }
 373
 374 static void show_line(struct grep_opt *opt, const char *bol, const char *eol,
 375                       const char *name, unsigned lno, char sign)
 376 {
 377         printf("%s%c", name, sign);
 378         if (opt->linenum)
 379                 printf("%d%c", lno, sign);
 380         printf("%.*s\n", (int)(eol-bol), bol);
 381 }
 382
 383 /*
 384  * NEEDSWORK: share code with diff.c
 385  */
 386 #define FIRST_FEW_BYTES 8000
 387 static int buffer_is_binary(const char *ptr, unsigned long size)
 388 {
 389         if (FIRST_FEW_BYTES < size)
 390                 size = FIRST_FEW_BYTES;
 391         if (memchr(ptr, 0, size))
 392                 return 1;
 393         return 0;
 394 }
 395
 396 static int fixmatch(const char *pattern, char *line, regmatch_t *match)
 397 {
 398         char *hit = strstr(line, pattern);
 399         if (!hit) {
 400                 match->rm_so = match->rm_eo = -1;
 401                 return REG_NOMATCH;
 402         }
 403         else {
 404                 match->rm_so = hit - line;
 405                 match->rm_eo = match->rm_so + strlen(pattern);
 406                 return 0;
 407         }
 408 }
 409
 410 static int match_one_pattern(struct grep_opt *opt, struct grep_pat *p, char *bol, char *eol)
 411 {
 412         int hit = 0;
 413         int at_true_bol = 1;
 414         regmatch_t pmatch[10];
 415
 416  again:
 417         if (!opt->fixed) {
 418                 regex_t *exp = &p->regexp;
 419                 hit = !regexec(exp, bol, ARRAY_SIZE(pmatch),
 420                                pmatch, 0);
 421         }
 422         else {
 423                 hit = !fixmatch(p->pattern, bol, pmatch);
 424         }
 425
 426         if (hit && opt->word_regexp) {
 427                 if ((pmatch[0].rm_so < 0) ||
 428                     (eol - bol) <= pmatch[0].rm_so ||
 429                     (pmatch[0].rm_eo < 0) ||
 430                     (eol - bol) < pmatch[0].rm_eo)
 431                         die("regexp returned nonsense");
 432
 433                 /* Match beginning must be either beginning of the
 434                  * line, or at word boundary (i.e. the last char must
 435                  * not be a word char).  Similarly, match end must be
 436                  * either end of the line, or at word boundary
 437                  * (i.e. the next char must not be a word char).
 438                  */
 439                 if ( ((pmatch[0].rm_so == 0 && at_true_bol) ||
 440                       !word_char(bol[pmatch[0].rm_so-1])) &&
 441                      ((pmatch[0].rm_eo == (eol-bol)) ||
 442                       !word_char(bol[pmatch[0].rm_eo])) )
 443                         ;
 444                 else
 445                         hit = 0;
 446
 447                 if (!hit && pmatch[0].rm_so + bol + 1 < eol) {
 448                         /* There could be more than one match on the
 449                          * line, and the first match might not be
 450                          * strict word match.  But later ones could be!
 451                          */
 452                         bol = pmatch[0].rm_so + bol + 1;
 453                         at_true_bol = 0;
 454                         goto again;
 455                 }
 456         }
 457         return hit;
 458 }
 459
 460 static int match_expr_eval(struct grep_opt *opt,
 461                            struct grep_expr *x,
 462                            char *bol, char *eol)
 463 {
 464         switch (x->node) {
 465         case GREP_NODE_ATOM:
 466                 return match_one_pattern(opt, x->u.atom, bol, eol);
 467                 break;
 468         case GREP_NODE_NOT:
 469                 return !match_expr_eval(opt, x->u.unary, bol, eol);
 470         case GREP_NODE_AND:
 471                 return (match_expr_eval(opt, x->u.binary.left, bol, eol) &&
 472                         match_expr_eval(opt, x->u.binary.right, bol, eol));
 473         case GREP_NODE_OR:
 474                 return (match_expr_eval(opt, x->u.binary.left, bol, eol) ||
 475                         match_expr_eval(opt, x->u.binary.right, bol, eol));
 476         }
 477         die("Unexpected node type (internal error) %d\n", x->node);
 478 }
 479
 480 static int match_expr(struct grep_opt *opt, char *bol, char *eol)
 481 {
 482         struct grep_expr *x = opt->pattern_expression;
 483         return match_expr_eval(opt, x, bol, eol);
 484 }
 485
 486 static int match_line(struct grep_opt *opt, char *bol, char *eol)
 487 {
 488         struct grep_pat *p;
 489         if (opt->extended)
 490                 return match_expr(opt, bol, eol);
 491         for (p = opt->pattern_list; p; p = p->next) {
 492                 if (match_one_pattern(opt, p, bol, eol))
 493                         return 1;
 494         }
 495         return 0;
 496 }
 497
 498 static int grep_buffer(struct grep_opt *opt, const char *name,
 499                        char *buf, unsigned long size)
 500 {
 501         char *bol = buf;
 502         unsigned long left = size;
 503         unsigned lno = 1;
 504         struct pre_context_line {
 505                 char *bol;
 506                 char *eol;
 507         } *prev = NULL, *pcl;
 508         unsigned last_hit = 0;
 509         unsigned last_shown = 0;
 510         int binary_match_only = 0;
 511         const char *hunk_mark = "";
 512         unsigned count = 0;
 513
 514         if (buffer_is_binary(buf, size)) {
 515                 switch (opt->binary) {
 516                 case GREP_BINARY_DEFAULT:
 517                         binary_match_only = 1;
 518                         break;
 519                 case GREP_BINARY_NOMATCH:
 520                         return 0; /* Assume unmatch */
 521                         break;
 522                 default:
 523                         break;
 524                 }
 525         }
 526
 527         if (opt->pre_context)
 528                 prev = xcalloc(opt->pre_context, sizeof(*prev));
 529         if (opt->pre_context || opt->post_context)
 530                 hunk_mark = "--\n";
 531
 532         while (left) {
 533                 char *eol, ch;
 534                 int hit = 0;
 535
 536                 eol = end_of_line(bol, &left);
 537                 ch = *eol;
 538                 *eol = 0;
 539
 540                 hit = match_line(opt, bol, eol);
 541
 542                 /* "grep -v -e foo -e bla" should list lines
 543                  * that do not have either, so inversion should
 544                  * be done outside.
 545                  */
 546                 if (opt->invert)
 547                         hit = !hit;
 548                 if (opt->unmatch_name_only) {
 549                         if (hit)
 550                                 return 0;
 551                         goto next_line;
 552                 }
 553                 if (hit) {
 554                         count++;
 555                         if (binary_match_only) {
 556                                 printf("Binary file %s matches\n", name);
 557                                 return 1;
 558                         }
 559                         if (opt->name_only) {
 560                                 printf("%s\n", name);
 561                                 return 1;
 562                         }
 563                         /* Hit at this line.  If we haven't shown the
 564                          * pre-context lines, we would need to show them.
 565                          * When asked to do "count", this still show
 566                          * the context which is nonsense, but the user
 567                          * deserves to get that ;-).
 568                          */
 569                         if (opt->pre_context) {
 570                                 unsigned from;
 571                                 if (opt->pre_context < lno)
 572                                         from = lno - opt->pre_context;
 573                                 else
 574                                         from = 1;
 575                                 if (from <= last_shown)
 576                                         from = last_shown + 1;
 577                                 if (last_shown && from != last_shown + 1)
 578                                         printf(hunk_mark);
 579                                 while (from < lno) {
 580                                         pcl = &prev[lno-from-1];
 581                                         show_line(opt, pcl->bol, pcl->eol,
 582                                                   name, from, '-');
 583                                         from++;
 584                                 }
 585                                 last_shown = lno-1;
 586                         }
 587                         if (last_shown && lno != last_shown + 1)
 588                                 printf(hunk_mark);
 589                         if (!opt->count)
 590                                 show_line(opt, bol, eol, name, lno, ':');
 591                         last_shown = last_hit = lno;
 592                 }
 593                 else if (last_hit &&
 594                          lno <= last_hit + opt->post_context) {
 595                         /* If the last hit is within the post context,
 596                          * we need to show this line.
 597                          */
 598                         if (last_shown && lno != last_shown + 1)
 599                                 printf(hunk_mark);
 600                         show_line(opt, bol, eol, name, lno, '-');
 601                         last_shown = lno;
 602                 }
 603                 if (opt->pre_context) {
 604                         memmove(prev+1, prev,
 605                                 (opt->pre_context-1) * sizeof(*prev));
 606                         prev->bol = bol;
 607                         prev->eol = eol;
 608                 }
 609
 610         next_line:
 611                 *eol = ch;
 612                 bol = eol + 1;
 613                 if (!left)
 614                         break;
 615                 left--;
 616                 lno++;
 617         }
 618
 619         if (opt->unmatch_name_only) {
 620                 /* We did not see any hit, so we want to show this */
 621                 printf("%s\n", name);
 622                 return 1;
 623         }
 624
 625         /* NEEDSWORK:
 626          * The real "grep -c foo *.c" gives many "bar.c:0" lines,
 627          * which feels mostly useless but sometimes useful.  Maybe
 628          * make it another option?  For now suppress them.
 629          */
 630         if (opt->count && count)
 631                 printf("%s:%u\n", name, count);
 632         return !!last_hit;
 633 }
 634
 635 static int grep_sha1(struct grep_opt *opt, const unsigned char *sha1, const char *name)
 636 {
 637         unsigned long size;
 638         char *data;
 639         char type[20];
 640         int hit;
 641         data = read_sha1_file(sha1, type, &size);
 642         if (!data) {
 643                 error("'%s': unable to read %s", name, sha1_to_hex(sha1));
 644                 return 0;
 645         }
 646         hit = grep_buffer(opt, name, data, size);
 647         free(data);
 648         return hit;
 649 }
 650
 651 static int grep_file(struct grep_opt *opt, const char *filename)
 652 {
 653         struct stat st;
 654         int i;
 655         char *data;
 656         if (lstat(filename, &st) < 0) {
 657         err_ret:
 658                 if (errno != ENOENT)
 659                         error("'%s': %s", filename, strerror(errno));
 660                 return 0;
 661         }
 662         if (!st.st_size)
 663                 return 0; /* empty file -- no grep hit */
 664         if (!S_ISREG(st.st_mode))
 665                 return 0;
 666         i = open(filename, O_RDONLY);
 667         if (i < 0)
 668                 goto err_ret;
 669         data = xmalloc(st.st_size + 1);
 670         if (st.st_size != xread(i, data, st.st_size)) {
 671                 error("'%s': short read %s", filename, strerror(errno));
 672                 close(i);
 673                 free(data);
 674                 return 0;
 675         }
 676         close(i);
 677         i = grep_buffer(opt, filename, data, st.st_size);
 678         free(data);
 679         return i;
 680 }
 681
 682 static int exec_grep(int argc, const char **argv)
 683 {
 684         pid_t pid;
 685         int status;
 686
 687         argv[argc] = NULL;
 688         pid = fork();
 689         if (pid < 0)
 690                 return pid;
 691         if (!pid) {
 692                 execvp("grep", (char **) argv);
 693                 exit(255);
 694         }
 695         while (waitpid(pid, &status, 0) < 0) {
 696                 if (errno == EINTR)
 697                         continue;
 698                 return -1;
 699         }
 700         if (WIFEXITED(status)) {
 701                 if (!WEXITSTATUS(status))
 702                         return 1;
 703                 return 0;
 704         }
 705         return -1;
 706 }
 707
 708 #define MAXARGS 1000
 709 #define ARGBUF 4096
 710 #define push_arg(a) do { \
 711         if (nr < MAXARGS) argv[nr++] = (a); \
 712         else die("maximum number of args exceeded"); \
 713         } while (0)
 714
 715 static int external_grep(struct grep_opt *opt, const char **paths, int cached)
 716 {
 717         int i, nr, argc, hit, len, status;
 718         const char *argv[MAXARGS+1];
 719         char randarg[ARGBUF];
 720         char *argptr = randarg;
 721         struct grep_pat *p;
 722
 723         if (opt->extended)
 724                 return -1;
 725         len = nr = 0;
 726         push_arg("grep");
 727         if (opt->fixed)
 728                 push_arg("-F");
 729         if (opt->linenum)
 730                 push_arg("-n");
 731         if (opt->regflags & REG_EXTENDED)
 732                 push_arg("-E");
 733         if (opt->regflags & REG_ICASE)
 734                 push_arg("-i");
 735         if (opt->word_regexp)
 736                 push_arg("-w");
 737         if (opt->name_only)
 738                 push_arg("-l");
 739         if (opt->unmatch_name_only)
 740                 push_arg("-L");
 741         if (opt->count)
 742                 push_arg("-c");
 743         if (opt->post_context || opt->pre_context) {
 744                 if (opt->post_context != opt->pre_context) {
 745                         if (opt->pre_context) {
 746                                 push_arg("-B");
 747                                 len += snprintf(argptr, sizeof(randarg)-len,
 748                                                 "%u", opt->pre_context);
 749                                 if (sizeof(randarg) <= len)
 750                                         die("maximum length of args exceeded");
 751                                 push_arg(argptr);
 752                                 argptr += len;
 753                         }
 754                         if (opt->post_context) {
 755                                 push_arg("-A");
 756                                 len += snprintf(argptr, sizeof(randarg)-len,
 757                                                 "%u", opt->post_context);
 758                                 if (sizeof(randarg) <= len)
 759                                         die("maximum length of args exceeded");
 760                                 push_arg(argptr);
 761                                 argptr += len;
 762                         }
 763                 }
 764                 else {
 765                         push_arg("-C");
 766                         len += snprintf(argptr, sizeof(randarg)-len,
 767                                         "%u", opt->post_context);
 768                         if (sizeof(randarg) <= len)
 769                                 die("maximum length of args exceeded");
 770                         push_arg(argptr);
 771                         argptr += len;
 772                 }
 773         }
 774         for (p = opt->pattern_list; p; p = p->next) {
 775                 push_arg("-e");
 776                 push_arg(p->pattern);
 777         }
 778
 779         /*
 780          * To make sure we get the header printed out when we want it,
 781          * add /dev/null to the paths to grep.  This is unnecessary
 782          * (and wrong) with "-l" or "-L", which always print out the
 783          * name anyway.
 784          *
 785          * GNU grep has "-H", but this is portable.
 786          */
 787         if (!opt->name_only && !opt->unmatch_name_only)
 788                 push_arg("/dev/null");
 789
 790         hit = 0;
 791         argc = nr;
 792         for (i = 0; i < active_nr; i++) {
 793                 struct cache_entry *ce = active_cache[i];
 794                 char *name;
 795                 if (ce_stage(ce) || !S_ISREG(ntohl(ce->ce_mode)))
 796                         continue;
 797                 if (!pathspec_matches(paths, ce->name))
 798                         continue;
 799                 name = ce->name;
 800                 if (name[0] == '-') {
 801                         int len = ce_namelen(ce);
 802                         name = xmalloc(len + 3);
 803                         memcpy(name, "./", 2);
 804                         memcpy(name + 2, ce->name, len + 1);
 805                 }
 806                 argv[argc++] = name;
 807                 if (argc < MAXARGS)
 808                         continue;
 809                 status = exec_grep(argc, argv);
 810                 if (0 < status)
 811                         hit = 1;
 812                 argc = nr;
 813         }
 814         if (argc > nr) {
 815                 status = exec_grep(argc, argv);
 816                 if (0 < status)
 817                         hit = 1;
 818         }
 819         return hit;
 820 }
 821
 822 static int grep_cache(struct grep_opt *opt, const char **paths, int cached)
 823 {
 824         int hit = 0;
 825         int nr;
 826         read_cache();
 827
 828 #ifdef __unix__
 829         /*
 830          * Use the external "grep" command for the case where
 831          * we grep through the checked-out files. It tends to
 832          * be a lot more optimized
 833          */
 834         if (!cached) {
 835                 hit = external_grep(opt, paths, cached);
 836                 if (hit >= 0)
 837                         return hit;
 838         }
 839 #endif
 840
 841         for (nr = 0; nr < active_nr; nr++) {
 842                 struct cache_entry *ce = active_cache[nr];
 843                 if (ce_stage(ce) || !S_ISREG(ntohl(ce->ce_mode)))
 844                         continue;
 845                 if (!pathspec_matches(paths, ce->name))
 846                         continue;
 847                 if (cached)
 848                         hit |= grep_sha1(opt, ce->sha1, ce->name);
 849                 else
 850                         hit |= grep_file(opt, ce->name);
 851         }
 852         return hit;
 853 }
 854
 855 static int grep_tree(struct grep_opt *opt, const char **paths,
 856                      struct tree_desc *tree,
 857                      const char *tree_name, const char *base)
 858 {
 859         int len;
 860         int hit = 0;
 861         struct name_entry entry;
 862         char *down;
 863         char *path_buf = xmalloc(PATH_MAX + strlen(tree_name) + 100);
 864
 865         if (tree_name[0]) {
 866                 int offset = sprintf(path_buf, "%s:", tree_name);
 867                 down = path_buf + offset;
 868                 strcat(down, base);
 869         }
 870         else {
 871                 down = path_buf;
 872                 strcpy(down, base);
 873         }
 874         len = strlen(path_buf);
 875
 876         while (tree_entry(tree, &entry)) {
 877                 strcpy(path_buf + len, entry.path);
 878
 879                 if (S_ISDIR(entry.mode))
 880                         /* Match "abc/" against pathspec to
 881                          * decide if we want to descend into "abc"
 882                          * directory.
 883                          */
 884                         strcpy(path_buf + len + entry.pathlen, "/");
 885
 886                 if (!pathspec_matches(paths, down))
 887                         ;
 888                 else if (S_ISREG(entry.mode))
 889                         hit |= grep_sha1(opt, entry.sha1, path_buf);
 890                 else if (S_ISDIR(entry.mode)) {
 891                         char type[20];
 892                         struct tree_desc sub;
 893                         void *data;
 894                         data = read_sha1_file(entry.sha1, type, &sub.size);
 895                         if (!data)
 896                                 die("unable to read tree (%s)",
 897                                     sha1_to_hex(entry.sha1));
 898                         sub.buf = data;
 899                         hit |= grep_tree(opt, paths, &sub, tree_name, down);
 900                         free(data);
 901                 }
 902         }
 903         return hit;
 904 }
 905
 906 static int grep_object(struct grep_opt *opt, const char **paths,
 907                        struct object *obj, const char *name)
 908 {
 909         if (obj->type == OBJ_BLOB)
 910                 return grep_sha1(opt, obj->sha1, name);
 911         if (obj->type == OBJ_COMMIT || obj->type == OBJ_TREE) {
 912                 struct tree_desc tree;
 913                 void *data;
 914                 int hit;
 915                 data = read_object_with_reference(obj->sha1, tree_type,
 916                                                   &tree.size, NULL);
 917                 if (!data)
 918                         die("unable to read tree (%s)", sha1_to_hex(obj->sha1));
 919                 tree.buf = data;
 920                 hit = grep_tree(opt, paths, &tree, name, "");
 921                 free(data);
 922                 return hit;
 923         }
 924         die("unable to grep from object of type %s", typename(obj->type));
 925 }
 926
 927 static const char builtin_grep_usage[] =
 928 "git-grep <option>* <rev>* [-e] <pattern> [<path>...]";
 929
 930 static const char emsg_invalid_context_len[] =
 931 "%s: invalid context length argument";
 932 static const char emsg_missing_context_len[] =
 933 "missing context length argument";
 934 static const char emsg_missing_argument[] =
 935 "option requires an argument -%s";
 936
 937 int cmd_grep(int argc, const char **argv, const char *prefix)
 938 {
 939         int hit = 0;
 940         int cached = 0;
 941         int seen_dashdash = 0;
 942         struct grep_opt opt;
 943         struct object_array list = { 0, 0, NULL };
 944         const char **paths = NULL;
 945         int i;
 946
 947         memset(&opt, 0, sizeof(opt));
 948         opt.pattern_tail = &opt.pattern_list;
 949         opt.regflags = REG_NEWLINE;
 950
 951         /*
 952          * If there is no -- then the paths must exist in the working
 953          * tree.  If there is no explicit pattern specified with -e or
 954          * -f, we take the first unrecognized non option to be the
 955          * pattern, but then what follows it must be zero or more
 956          * valid refs up to the -- (if exists), and then existing
 957          * paths.  If there is an explicit pattern, then the first
 958          * unrecognized non option is the beginning of the refs list
 959          * that continues up to the -- (if exists), and then paths.
 960          */
 961
 962         while (1 < argc) {
 963                 const char *arg = argv[1];
 964                 argc--; argv++;
 965                 if (!strcmp("--cached", arg)) {
 966                         cached = 1;
 967                         continue;
 968                 }
 969                 if (!strcmp("-a", arg) ||
 970                     !strcmp("--text", arg)) {
 971                         opt.binary = GREP_BINARY_TEXT;
 972                         continue;
 973                 }
 974                 if (!strcmp("-i", arg) ||
 975                     !strcmp("--ignore-case", arg)) {
 976                         opt.regflags |= REG_ICASE;
 977                         continue;
 978                 }
 979                 if (!strcmp("-I", arg)) {
 980                         opt.binary = GREP_BINARY_NOMATCH;
 981                         continue;
 982                 }
 983                 if (!strcmp("-v", arg) ||
 984                     !strcmp("--invert-match", arg)) {
 985                         opt.invert = 1;
 986                         continue;
 987                 }
 988                 if (!strcmp("-E", arg) ||
 989                     !strcmp("--extended-regexp", arg)) {
 990                         opt.regflags |= REG_EXTENDED;
 991                         continue;
 992                 }
 993                 if (!strcmp("-F", arg) ||
 994                     !strcmp("--fixed-strings", arg)) {
 995                         opt.fixed = 1;
 996                         continue;
 997                 }
 998                 if (!strcmp("-G", arg) ||
 999                     !strcmp("--basic-regexp", arg)) {
1000                         opt.regflags &= ~REG_EXTENDED;
1001                         continue;
1002                 }
1003                 if (!strcmp("-n", arg)) {
1004                         opt.linenum = 1;
1005                         continue;
1006                 }
1007                 if (!strcmp("-H", arg)) {
1008                         /* We always show the pathname, so this
1009                          * is a noop.
1010                          */
1011                         continue;
1012                 }
1013                 if (!strcmp("-l", arg) ||
1014                     !strcmp("--files-with-matches", arg)) {
1015                         opt.name_only = 1;
1016                         continue;
1017                 }
1018                 if (!strcmp("-L", arg) ||
1019                     !strcmp("--files-without-match", arg)) {
1020                         opt.unmatch_name_only = 1;
1021                         continue;
1022                 }
1023                 if (!strcmp("-c", arg) ||
1024                     !strcmp("--count", arg)) {
1025                         opt.count = 1;
1026                         continue;
1027                 }
1028                 if (!strcmp("-w", arg) ||
1029                     !strcmp("--word-regexp", arg)) {
1030                         opt.word_regexp = 1;
1031                         continue;
1032                 }
1033                 if (!strncmp("-A", arg, 2) ||
1034                     !strncmp("-B", arg, 2) ||
1035                     !strncmp("-C", arg, 2) ||
1036                     (arg[0] == '-' && '1' <= arg[1] && arg[1] <= '9')) {
1037                         unsigned num;
1038                         const char *scan;
1039                         switch (arg[1]) {
1040                         case 'A': case 'B': case 'C':
1041                                 if (!arg[2]) {
1042                                         if (argc <= 1)
1043                                                 die(emsg_missing_context_len);
1044                                         scan = *++argv;
1045                                         argc--;
1046                                 }
1047                                 else
1048                                         scan = arg + 2;
1049                                 break;
1050                         default:
1051                                 scan = arg + 1;
1052                                 break;
1053                         }
1054                         if (sscanf(scan, "%u", &num) != 1)
1055                                 die(emsg_invalid_context_len, scan);
1056                         switch (arg[1]) {
1057                         case 'A':
1058                                 opt.post_context = num;
1059                                 break;
1060                         default:
1061                         case 'C':
1062                                 opt.post_context = num;
1063                         case 'B':
1064                                 opt.pre_context = num;
1065                                 break;
1066                         }
1067                         continue;
1068                 }
1069                 if (!strcmp("-f", arg)) {
1070                         FILE *patterns;
1071                         int lno = 0;
1072                         char buf[1024];
1073                         if (argc <= 1)
1074                                 die(emsg_missing_argument, arg);
1075                         patterns = fopen(argv[1], "r");
1076                         if (!patterns)
1077                                 die("'%s': %s", argv[1], strerror(errno));
1078                         while (fgets(buf, sizeof(buf), patterns)) {
1079                                 int len = strlen(buf);
1080                                 if (buf[len-1] == '\n')
1081                                         buf[len-1] = 0;
1082                                 /* ignore empty line like grep does */
1083                                 if (!buf[0])
1084                                         continue;
1085                                 add_pattern(&opt, strdup(buf), argv[1], ++lno,
1086                                             GREP_PATTERN);
1087                         }
1088                         fclose(patterns);
1089                         argv++;
1090                         argc--;
1091                         continue;
1092                 }
1093                 if (!strcmp("--not", arg)) {
1094                         add_pattern(&opt, arg, "command line", 0, GREP_NOT);
1095                         continue;
1096                 }
1097                 if (!strcmp("--and", arg)) {
1098                         add_pattern(&opt, arg, "command line", 0, GREP_AND);
1099                         continue;
1100                 }
1101                 if (!strcmp("--or", arg))
1102                         continue; /* no-op */
1103                 if (!strcmp("(", arg)) {
1104                         add_pattern(&opt, arg, "command line", 0, GREP_OPEN_PAREN);
1105                         continue;
1106                 }
1107                 if (!strcmp(")", arg)) {
1108                         add_pattern(&opt, arg, "command line", 0, GREP_CLOSE_PAREN);
1109                         continue;
1110                 }
1111                 if (!strcmp("-e", arg)) {
1112                         if (1 < argc) {
1113                                 add_pattern(&opt, argv[1], "-e option", 0,
1114                                             GREP_PATTERN);
1115                                 argv++;
1116                                 argc--;
1117                                 continue;
1118                         }
1119                         die(emsg_missing_argument, arg);
1120                 }
1121                 if (!strcmp("--", arg)) {
1122                         /* later processing wants to have this at argv[1] */
1123                         argv--;
1124                         argc++;
1125                         break;
1126                 }
1127                 if (*arg == '-')
1128                         usage(builtin_grep_usage);
1129
1130                 /* First unrecognized non-option token */
1131                 if (!opt.pattern_list) {
1132                         add_pattern(&opt, arg, "command line", 0,
1133                                     GREP_PATTERN);
1134                         break;
1135                 }
1136                 else {
1137                         /* We are looking at the first path or rev;
1138                          * it is found at argv[1] after leaving the
1139                          * loop.
1140                          */
1141                         argc++; argv--;
1142                         break;
1143                 }
1144         }
1145
1146         if (!opt.pattern_list)
1147                 die("no pattern given.");
1148         if ((opt.regflags != REG_NEWLINE) && opt.fixed)
1149                 die("cannot mix --fixed-strings and regexp");
1150         if (!opt.fixed)
1151                 compile_patterns(&opt);
1152
1153         /* Check revs and then paths */
1154         for (i = 1; i < argc; i++) {
1155                 const char *arg = argv[i];
1156                 unsigned char sha1[20];
1157                 /* Is it a rev? */
1158                 if (!get_sha1(arg, sha1)) {
1159                         struct object *object = parse_object(sha1);
1160                         if (!object)
1161                                 die("bad object %s", arg);
1162                         add_object_array(object, arg, &list);
1163                         continue;
1164                 }
1165                 if (!strcmp(arg, "--")) {
1166                         i++;
1167                         seen_dashdash = 1;
1168                 }
1169                 break;
1170         }
1171
1172         /* The rest are paths */
1173         if (!seen_dashdash) {
1174                 int j;
1175                 for (j = i; j < argc; j++)
1176                         verify_filename(prefix, argv[j]);
1177         }
1178
1179         if (i < argc)
1180                 paths = get_pathspec(prefix, argv + i);
1181         else if (prefix) {
1182                 paths = xcalloc(2, sizeof(const char *));
1183                 paths[0] = prefix;
1184                 paths[1] = NULL;
1185         }
1186
1187         if (!list.nr)
1188                 return !grep_cache(&opt, paths, cached);
1189
1190         if (cached)
1191                 die("both --cached and trees are given.");
1192
1193         for (i = 0; i < list.nr; i++) {
1194                 struct object *real_obj;
1195                 real_obj = deref_tag(list.objects[i].item, NULL, 0);
1196                 if (grep_object(&opt, paths, real_obj, list.objects[i].name))
1197                         hit = 1;
1198         }
1199         return !hit;
1200 }