grep.c

   1 #include "cache.h"
   2 #include "grep.h"
   3 #include "userdiff.h"
   4 #include "xdiff-interface.h"
   5
   6 void append_header_grep_pattern(struct grep_opt *opt, enum grep_header_field field, const char *pat)
   7 {
   8         struct grep_pat *p = xcalloc(1, sizeof(*p));
   9         p->pattern = pat;
  10         p->patternlen = strlen(pat);
  11         p->origin = "header";
  12         p->no = 0;
  13         p->token = GREP_PATTERN_HEAD;
  14         p->field = field;
  15         *opt->header_tail = p;
  16         opt->header_tail = &p->next;
  17         p->next = NULL;
  18 }
  19
  20 void append_grep_pattern(struct grep_opt *opt, const char *pat,
  21                          const char *origin, int no, enum grep_pat_token t)
  22 {
  23         append_grep_pat(opt, pat, strlen(pat), origin, no, t);
  24 }
  25
  26 void append_grep_pat(struct grep_opt *opt, const char *pat, size_t patlen,
  27                      const char *origin, int no, enum grep_pat_token t)
  28 {
  29         struct grep_pat *p = xcalloc(1, sizeof(*p));
  30         p->pattern = pat;
  31         p->patternlen = patlen;
  32         p->origin = origin;
  33         p->no = no;
  34         p->token = t;
  35         *opt->pattern_tail = p;
  36         opt->pattern_tail = &p->next;
  37         p->next = NULL;
  38 }
  39
  40 struct grep_opt *grep_opt_dup(const struct grep_opt *opt)
  41 {
  42         struct grep_pat *pat;
  43         struct grep_opt *ret = xmalloc(sizeof(struct grep_opt));
  44         *ret = *opt;
  45
  46         ret->pattern_list = NULL;
  47         ret->pattern_tail = &ret->pattern_list;
  48
  49         for(pat = opt->pattern_list; pat != NULL; pat = pat->next)
  50         {
  51                 if(pat->token == GREP_PATTERN_HEAD)
  52                         append_header_grep_pattern(ret, pat->field,
  53                                                    pat->pattern);
  54                 else
  55                         append_grep_pat(ret, pat->pattern, pat->patternlen,
  56                                         pat->origin, pat->no, pat->token);
  57         }
  58
  59         return ret;
  60 }
  61
  62 static NORETURN void compile_regexp_failed(const struct grep_pat *p,
  63                 const char *error)
  64 {
  65         char where[1024];
  66
  67         if (p->no)
  68                 sprintf(where, "In '%s' at %d, ", p->origin, p->no);
  69         else if (p->origin)
  70                 sprintf(where, "%s, ", p->origin);
  71         else
  72                 where[0] = 0;
  73
  74         die("%s'%s': %s", where, p->pattern, error);
  75 }
  76
  77 #ifdef USE_LIBPCRE
  78 static void compile_pcre_regexp(struct grep_pat *p, const struct grep_opt *opt)
  79 {
  80         const char *error;
  81         int erroffset;
  82         int options = PCRE_MULTILINE;
  83
  84         if (opt->ignore_case)
  85                 options |= PCRE_CASELESS;
  86
  87         p->pcre_regexp = pcre_compile(p->pattern, options, &error, &erroffset,
  88                         NULL);
  89         if (!p->pcre_regexp)
  90                 compile_regexp_failed(p, error);
  91
  92         p->pcre_extra_info = pcre_study(p->pcre_regexp, 0, &error);
  93         if (!p->pcre_extra_info && error)
  94                 die("%s", error);
  95 }
  96
  97 static int pcrematch(struct grep_pat *p, const char *line, const char *eol,
  98                 regmatch_t *match, int eflags)
  99 {
 100         int ovector[30], ret, flags = 0;
 101
 102         if (eflags & REG_NOTBOL)
 103                 flags |= PCRE_NOTBOL;
 104
 105         ret = pcre_exec(p->pcre_regexp, p->pcre_extra_info, line, eol - line,
 106                         0, flags, ovector, ARRAY_SIZE(ovector));
 107         if (ret < 0 && ret != PCRE_ERROR_NOMATCH)
 108                 die("pcre_exec failed with error code %d", ret);
 109         if (ret > 0) {
 110                 ret = 0;
 111                 match->rm_so = ovector[0];
 112                 match->rm_eo = ovector[1];
 113         }
 114
 115         return ret;
 116 }
 117
 118 static void free_pcre_regexp(struct grep_pat *p)
 119 {
 120         pcre_free(p->pcre_regexp);
 121         pcre_free(p->pcre_extra_info);
 122 }
 123 #else /* !USE_LIBPCRE */
 124 static void compile_pcre_regexp(struct grep_pat *p, const struct grep_opt *opt)
 125 {
 126         die("cannot use Perl-compatible regexes when not compiled with USE_LIBPCRE");
 127 }
 128
 129 static int pcrematch(struct grep_pat *p, const char *line, const char *eol,
 130                 regmatch_t *match, int eflags)
 131 {
 132         return 1;
 133 }
 134
 135 static void free_pcre_regexp(struct grep_pat *p)
 136 {
 137 }
 138 #endif /* !USE_LIBPCRE */
 139
 140 static int is_fixed(const char *s, size_t len)
 141 {
 142         size_t i;
 143
 144         /* regcomp cannot accept patterns with NULs so we
 145          * consider any pattern containing a NUL fixed.
 146          */
 147         if (memchr(s, 0, len))
 148                 return 1;
 149
 150         for (i = 0; i < len; i++) {
 151                 if (is_regex_special(s[i]))
 152                         return 0;
 153         }
 154
 155         return 1;
 156 }
 157
 158 static void compile_regexp(struct grep_pat *p, struct grep_opt *opt)
 159 {
 160         int err;
 161
 162         p->word_regexp = opt->word_regexp;
 163         p->ignore_case = opt->ignore_case;
 164
 165         if (opt->fixed || is_fixed(p->pattern, p->patternlen))
 166                 p->fixed = 1;
 167         else
 168                 p->fixed = 0;
 169
 170         if (p->fixed) {
 171                 if (opt->regflags & REG_ICASE || p->ignore_case) {
 172                         static char trans[256];
 173                         int i;
 174                         for (i = 0; i < 256; i++)
 175                                 trans[i] = tolower(i);
 176                         p->kws = kwsalloc(trans);
 177                 } else {
 178                         p->kws = kwsalloc(NULL);
 179                 }
 180                 kwsincr(p->kws, p->pattern, p->patternlen);
 181                 kwsprep(p->kws);
 182                 return;
 183         }
 184
 185         if (opt->pcre) {
 186                 compile_pcre_regexp(p, opt);
 187                 return;
 188         }
 189
 190         err = regcomp(&p->regexp, p->pattern, opt->regflags);
 191         if (err) {
 192                 char errbuf[1024];
 193                 regerror(err, &p->regexp, errbuf, 1024);
 194                 regfree(&p->regexp);
 195                 compile_regexp_failed(p, errbuf);
 196         }
 197 }
 198
 199 static struct grep_expr *compile_pattern_or(struct grep_pat **);
 200 static struct grep_expr *compile_pattern_atom(struct grep_pat **list)
 201 {
 202         struct grep_pat *p;
 203         struct grep_expr *x;
 204
 205         p = *list;
 206         if (!p)
 207                 return NULL;
 208         switch (p->token) {
 209         case GREP_PATTERN: /* atom */
 210         case GREP_PATTERN_HEAD:
 211         case GREP_PATTERN_BODY:
 212                 x = xcalloc(1, sizeof (struct grep_expr));
 213                 x->node = GREP_NODE_ATOM;
 214                 x->u.atom = p;
 215                 *list = p->next;
 216                 return x;
 217         case GREP_OPEN_PAREN:
 218                 *list = p->next;
 219                 x = compile_pattern_or(list);
 220                 if (!*list || (*list)->token != GREP_CLOSE_PAREN)
 221                         die("unmatched parenthesis");
 222                 *list = (*list)->next;
 223                 return x;
 224         default:
 225                 return NULL;
 226         }
 227 }
 228
 229 static struct grep_expr *compile_pattern_not(struct grep_pat **list)
 230 {
 231         struct grep_pat *p;
 232         struct grep_expr *x;
 233
 234         p = *list;
 235         if (!p)
 236                 return NULL;
 237         switch (p->token) {
 238         case GREP_NOT:
 239                 if (!p->next)
 240                         die("--not not followed by pattern expression");
 241                 *list = p->next;
 242                 x = xcalloc(1, sizeof (struct grep_expr));
 243                 x->node = GREP_NODE_NOT;
 244                 x->u.unary = compile_pattern_not(list);
 245                 if (!x->u.unary)
 246                         die("--not followed by non pattern expression");
 247                 return x;
 248         default:
 249                 return compile_pattern_atom(list);
 250         }
 251 }
 252
 253 static struct grep_expr *compile_pattern_and(struct grep_pat **list)
 254 {
 255         struct grep_pat *p;
 256         struct grep_expr *x, *y, *z;
 257
 258         x = compile_pattern_not(list);
 259         p = *list;
 260         if (p && p->token == GREP_AND) {
 261                 if (!p->next)
 262                         die("--and not followed by pattern expression");
 263                 *list = p->next;
 264                 y = compile_pattern_and(list);
 265                 if (!y)
 266                         die("--and not followed by pattern expression");
 267                 z = xcalloc(1, sizeof (struct grep_expr));
 268                 z->node = GREP_NODE_AND;
 269                 z->u.binary.left = x;
 270                 z->u.binary.right = y;
 271                 return z;
 272         }
 273         return x;
 274 }
 275
 276 static struct grep_expr *compile_pattern_or(struct grep_pat **list)
 277 {
 278         struct grep_pat *p;
 279         struct grep_expr *x, *y, *z;
 280
 281         x = compile_pattern_and(list);
 282         p = *list;
 283         if (x && p && p->token != GREP_CLOSE_PAREN) {
 284                 y = compile_pattern_or(list);
 285                 if (!y)
 286                         die("not a pattern expression %s", p->pattern);
 287                 z = xcalloc(1, sizeof (struct grep_expr));
 288                 z->node = GREP_NODE_OR;
 289                 z->u.binary.left = x;
 290                 z->u.binary.right = y;
 291                 return z;
 292         }
 293         return x;
 294 }
 295
 296 static struct grep_expr *compile_pattern_expr(struct grep_pat **list)
 297 {
 298         return compile_pattern_or(list);
 299 }
 300
 301 static struct grep_expr *grep_true_expr(void)
 302 {
 303         struct grep_expr *z = xcalloc(1, sizeof(*z));
 304         z->node = GREP_NODE_TRUE;
 305         return z;
 306 }
 307
 308 static struct grep_expr *grep_or_expr(struct grep_expr *left, struct grep_expr *right)
 309 {
 310         struct grep_expr *z = xcalloc(1, sizeof(*z));
 311         z->node = GREP_NODE_OR;
 312         z->u.binary.left = left;
 313         z->u.binary.right = right;
 314         return z;
 315 }
 316
 317 static struct grep_expr *prep_header_patterns(struct grep_opt *opt)
 318 {
 319         struct grep_pat *p;
 320         struct grep_expr *header_expr;
 321         struct grep_expr *(header_group[GREP_HEADER_FIELD_MAX]);
 322         enum grep_header_field fld;
 323
 324         if (!opt->header_list)
 325                 return NULL;
 326         p = opt->header_list;
 327         for (p = opt->header_list; p; p = p->next) {
 328                 if (p->token != GREP_PATTERN_HEAD)
 329                         die("bug: a non-header pattern in grep header list.");
 330                 if (p->field < 0 || GREP_HEADER_FIELD_MAX <= p->field)
 331                         die("bug: unknown header field %d", p->field);
 332                 compile_regexp(p, opt);
 333         }
 334
 335         for (fld = 0; fld < GREP_HEADER_FIELD_MAX; fld++)
 336                 header_group[fld] = NULL;
 337
 338         for (p = opt->header_list; p; p = p->next) {
 339                 struct grep_expr *h;
 340                 struct grep_pat *pp = p;
 341
 342                 h = compile_pattern_atom(&pp);
 343                 if (!h || pp != p->next)
 344                         die("bug: malformed header expr");
 345                 if (!header_group[p->field]) {
 346                         header_group[p->field] = h;
 347                         continue;
 348                 }
 349                 header_group[p->field] = grep_or_expr(h, header_group[p->field]);
 350         }
 351
 352         header_expr = NULL;
 353
 354         for (fld = 0; fld < GREP_HEADER_FIELD_MAX; fld++) {
 355                 if (!header_group[fld])
 356                         continue;
 357                 if (!header_expr)
 358                         header_expr = grep_true_expr();
 359                 header_expr = grep_or_expr(header_group[fld], header_expr);
 360         }
 361         return header_expr;
 362 }
 363
 364 void compile_grep_patterns(struct grep_opt *opt)
 365 {
 366         struct grep_pat *p;
 367         struct grep_expr *header_expr = prep_header_patterns(opt);
 368
 369         for (p = opt->pattern_list; p; p = p->next) {
 370                 switch (p->token) {
 371                 case GREP_PATTERN: /* atom */
 372                 case GREP_PATTERN_HEAD:
 373                 case GREP_PATTERN_BODY:
 374                         compile_regexp(p, opt);
 375                         break;
 376                 default:
 377                         opt->extended = 1;
 378                         break;
 379                 }
 380         }
 381
 382         if (opt->all_match || header_expr)
 383                 opt->extended = 1;
 384         else if (!opt->extended)
 385                 return;
 386
 387         p = opt->pattern_list;
 388         if (p)
 389                 opt->pattern_expression = compile_pattern_expr(&p);
 390         if (p)
 391                 die("incomplete pattern expression: %s", p->pattern);
 392
 393         if (!header_expr)
 394                 return;
 395
 396         if (!opt->pattern_expression)
 397                 opt->pattern_expression = header_expr;
 398         else
 399                 opt->pattern_expression = grep_or_expr(opt->pattern_expression,
 400                                                        header_expr);
 401         opt->all_match = 1;
 402 }
 403
 404 static void free_pattern_expr(struct grep_expr *x)
 405 {
 406         switch (x->node) {
 407         case GREP_NODE_TRUE:
 408         case GREP_NODE_ATOM:
 409                 break;
 410         case GREP_NODE_NOT:
 411                 free_pattern_expr(x->u.unary);
 412                 break;
 413         case GREP_NODE_AND:
 414         case GREP_NODE_OR:
 415                 free_pattern_expr(x->u.binary.left);
 416                 free_pattern_expr(x->u.binary.right);
 417                 break;
 418         }
 419         free(x);
 420 }
 421
 422 void free_grep_patterns(struct grep_opt *opt)
 423 {
 424         struct grep_pat *p, *n;
 425
 426         for (p = opt->pattern_list; p; p = n) {
 427                 n = p->next;
 428                 switch (p->token) {
 429                 case GREP_PATTERN: /* atom */
 430                 case GREP_PATTERN_HEAD:
 431                 case GREP_PATTERN_BODY:
 432                         if (p->kws)
 433                                 kwsfree(p->kws);
 434                         else if (p->pcre_regexp)
 435                                 free_pcre_regexp(p);
 436                         else
 437                                 regfree(&p->regexp);
 438                         break;
 439                 default:
 440                         break;
 441                 }
 442                 free(p);
 443         }
 444
 445         if (!opt->extended)
 446                 return;
 447         free_pattern_expr(opt->pattern_expression);
 448 }
 449
 450 static char *end_of_line(char *cp, unsigned long *left)
 451 {
 452         unsigned long l = *left;
 453         while (l && *cp != '\n') {
 454                 l--;
 455                 cp++;
 456         }
 457         *left = l;
 458         return cp;
 459 }
 460
 461 static int word_char(char ch)
 462 {
 463         return isalnum(ch) || ch == '_';
 464 }
 465
 466 static void output_color(struct grep_opt *opt, const void *data, size_t size,
 467                          const char *color)
 468 {
 469         if (want_color(opt->color) && color && color[0]) {
 470                 opt->output(opt, color, strlen(color));
 471                 opt->output(opt, data, size);
 472                 opt->output(opt, GIT_COLOR_RESET, strlen(GIT_COLOR_RESET));
 473         } else
 474                 opt->output(opt, data, size);
 475 }
 476
 477 static void output_sep(struct grep_opt *opt, char sign)
 478 {
 479         if (opt->null_following_name)
 480                 opt->output(opt, "\0", 1);
 481         else
 482                 output_color(opt, &sign, 1, opt->color_sep);
 483 }
 484
 485 static void show_name(struct grep_opt *opt, const char *name)
 486 {
 487         output_color(opt, name, strlen(name), opt->color_filename);
 488         opt->output(opt, opt->null_following_name ? "\0" : "\n", 1);
 489 }
 490
 491 static int fixmatch(struct grep_pat *p, char *line, char *eol,
 492                     regmatch_t *match)
 493 {
 494         struct kwsmatch kwsm;
 495         size_t offset = kwsexec(p->kws, line, eol - line, &kwsm);
 496         if (offset == -1) {
 497                 match->rm_so = match->rm_eo = -1;
 498                 return REG_NOMATCH;
 499         } else {
 500                 match->rm_so = offset;
 501                 match->rm_eo = match->rm_so + kwsm.size[0];
 502                 return 0;
 503         }
 504 }
 505
 506 static int regmatch(const regex_t *preg, char *line, char *eol,
 507                     regmatch_t *match, int eflags)
 508 {
 509 #ifdef REG_STARTEND
 510         match->rm_so = 0;
 511         match->rm_eo = eol - line;
 512         eflags |= REG_STARTEND;
 513 #endif
 514         return regexec(preg, line, 1, match, eflags);
 515 }
 516
 517 static int patmatch(struct grep_pat *p, char *line, char *eol,
 518                     regmatch_t *match, int eflags)
 519 {
 520         int hit;
 521
 522         if (p->fixed)
 523                 hit = !fixmatch(p, line, eol, match);
 524         else if (p->pcre_regexp)
 525                 hit = !pcrematch(p, line, eol, match, eflags);
 526         else
 527                 hit = !regmatch(&p->regexp, line, eol, match, eflags);
 528
 529         return hit;
 530 }
 531
 532 static int strip_timestamp(char *bol, char **eol_p)
 533 {
 534         char *eol = *eol_p;
 535         int ch;
 536
 537         while (bol < --eol) {
 538                 if (*eol != '>')
 539                         continue;
 540                 *eol_p = ++eol;
 541                 ch = *eol;
 542                 *eol = '\0';
 543                 return ch;
 544         }
 545         return 0;
 546 }
 547
 548 static struct {
 549         const char *field;
 550         size_t len;
 551 } header_field[] = {
 552         { "author ", 7 },
 553         { "committer ", 10 },
 554 };
 555
 556 static int match_one_pattern(struct grep_pat *p, char *bol, char *eol,
 557                              enum grep_context ctx,
 558                              regmatch_t *pmatch, int eflags)
 559 {
 560         int hit = 0;
 561         int saved_ch = 0;
 562         const char *start = bol;
 563
 564         if ((p->token != GREP_PATTERN) &&
 565             ((p->token == GREP_PATTERN_HEAD) != (ctx == GREP_CONTEXT_HEAD)))
 566                 return 0;
 567
 568         if (p->token == GREP_PATTERN_HEAD) {
 569                 const char *field;
 570                 size_t len;
 571                 assert(p->field < ARRAY_SIZE(header_field));
 572                 field = header_field[p->field].field;
 573                 len = header_field[p->field].len;
 574                 if (strncmp(bol, field, len))
 575                         return 0;
 576                 bol += len;
 577                 saved_ch = strip_timestamp(bol, &eol);
 578         }
 579
 580  again:
 581         hit = patmatch(p, bol, eol, pmatch, eflags);
 582
 583         if (hit && p->word_regexp) {
 584                 if ((pmatch[0].rm_so < 0) ||
 585                     (eol - bol) < pmatch[0].rm_so ||
 586                     (pmatch[0].rm_eo < 0) ||
 587                     (eol - bol) < pmatch[0].rm_eo)
 588                         die("regexp returned nonsense");
 589
 590                 /* Match beginning must be either beginning of the
 591                  * line, or at word boundary (i.e. the last char must
 592                  * not be a word char).  Similarly, match end must be
 593                  * either end of the line, or at word boundary
 594                  * (i.e. the next char must not be a word char).
 595                  */
 596                 if ( ((pmatch[0].rm_so == 0) ||
 597                       !word_char(bol[pmatch[0].rm_so-1])) &&
 598                      ((pmatch[0].rm_eo == (eol-bol)) ||
 599                       !word_char(bol[pmatch[0].rm_eo])) )
 600                         ;
 601                 else
 602                         hit = 0;
 603
 604                 /* Words consist of at least one character. */
 605                 if (pmatch->rm_so == pmatch->rm_eo)
 606                         hit = 0;
 607
 608                 if (!hit && pmatch[0].rm_so + bol + 1 < eol) {
 609                         /* There could be more than one match on the
 610                          * line, and the first match might not be
 611                          * strict word match.  But later ones could be!
 612                          * Forward to the next possible start, i.e. the
 613                          * next position following a non-word char.
 614                          */
 615                         bol = pmatch[0].rm_so + bol + 1;
 616                         while (word_char(bol[-1]) && bol < eol)
 617                                 bol++;
 618                         eflags |= REG_NOTBOL;
 619                         if (bol < eol)
 620                                 goto again;
 621                 }
 622         }
 623         if (p->token == GREP_PATTERN_HEAD && saved_ch)
 624                 *eol = saved_ch;
 625         if (hit) {
 626                 pmatch[0].rm_so += bol - start;
 627                 pmatch[0].rm_eo += bol - start;
 628         }
 629         return hit;
 630 }
 631
 632 static int match_expr_eval(struct grep_expr *x, char *bol, char *eol,
 633                            enum grep_context ctx, int collect_hits)
 634 {
 635         int h = 0;
 636         regmatch_t match;
 637
 638         if (!x)
 639                 die("Not a valid grep expression");
 640         switch (x->node) {
 641         case GREP_NODE_TRUE:
 642                 h = 1;
 643                 break;
 644         case GREP_NODE_ATOM:
 645                 h = match_one_pattern(x->u.atom, bol, eol, ctx, &match, 0);
 646                 break;
 647         case GREP_NODE_NOT:
 648                 h = !match_expr_eval(x->u.unary, bol, eol, ctx, 0);
 649                 break;
 650         case GREP_NODE_AND:
 651                 if (!match_expr_eval(x->u.binary.left, bol, eol, ctx, 0))
 652                         return 0;
 653                 h = match_expr_eval(x->u.binary.right, bol, eol, ctx, 0);
 654                 break;
 655         case GREP_NODE_OR:
 656                 if (!collect_hits)
 657                         return (match_expr_eval(x->u.binary.left,
 658                                                 bol, eol, ctx, 0) ||
 659                                 match_expr_eval(x->u.binary.right,
 660                                                 bol, eol, ctx, 0));
 661                 h = match_expr_eval(x->u.binary.left, bol, eol, ctx, 0);
 662                 x->u.binary.left->hit |= h;
 663                 h |= match_expr_eval(x->u.binary.right, bol, eol, ctx, 1);
 664                 break;
 665         default:
 666                 die("Unexpected node type (internal error) %d", x->node);
 667         }
 668         if (collect_hits)
 669                 x->hit |= h;
 670         return h;
 671 }
 672
 673 static int match_expr(struct grep_opt *opt, char *bol, char *eol,
 674                       enum grep_context ctx, int collect_hits)
 675 {
 676         struct grep_expr *x = opt->pattern_expression;
 677         return match_expr_eval(x, bol, eol, ctx, collect_hits);
 678 }
 679
 680 static int match_line(struct grep_opt *opt, char *bol, char *eol,
 681                       enum grep_context ctx, int collect_hits)
 682 {
 683         struct grep_pat *p;
 684         regmatch_t match;
 685
 686         if (opt->extended)
 687                 return match_expr(opt, bol, eol, ctx, collect_hits);
 688
 689         /* we do not call with collect_hits without being extended */
 690         for (p = opt->pattern_list; p; p = p->next) {
 691                 if (match_one_pattern(p, bol, eol, ctx, &match, 0))
 692                         return 1;
 693         }
 694         return 0;
 695 }
 696
 697 static int match_next_pattern(struct grep_pat *p, char *bol, char *eol,
 698                               enum grep_context ctx,
 699                               regmatch_t *pmatch, int eflags)
 700 {
 701         regmatch_t match;
 702
 703         if (!match_one_pattern(p, bol, eol, ctx, &match, eflags))
 704                 return 0;
 705         if (match.rm_so < 0 || match.rm_eo < 0)
 706                 return 0;
 707         if (pmatch->rm_so >= 0 && pmatch->rm_eo >= 0) {
 708                 if (match.rm_so > pmatch->rm_so)
 709                         return 1;
 710                 if (match.rm_so == pmatch->rm_so && match.rm_eo < pmatch->rm_eo)
 711                         return 1;
 712         }
 713         pmatch->rm_so = match.rm_so;
 714         pmatch->rm_eo = match.rm_eo;
 715         return 1;
 716 }
 717
 718 static int next_match(struct grep_opt *opt, char *bol, char *eol,
 719                       enum grep_context ctx, regmatch_t *pmatch, int eflags)
 720 {
 721         struct grep_pat *p;
 722         int hit = 0;
 723
 724         pmatch->rm_so = pmatch->rm_eo = -1;
 725         if (bol < eol) {
 726                 for (p = opt->pattern_list; p; p = p->next) {
 727                         switch (p->token) {
 728                         case GREP_PATTERN: /* atom */
 729                         case GREP_PATTERN_HEAD:
 730                         case GREP_PATTERN_BODY:
 731                                 hit |= match_next_pattern(p, bol, eol, ctx,
 732                                                           pmatch, eflags);
 733                                 break;
 734                         default:
 735                                 break;
 736                         }
 737                 }
 738         }
 739         return hit;
 740 }
 741
 742 static void show_line(struct grep_opt *opt, char *bol, char *eol,
 743                       const char *name, unsigned lno, char sign)
 744 {
 745         int rest = eol - bol;
 746         char *line_color = NULL;
 747
 748         if (opt->file_break && opt->last_shown == 0) {
 749                 if (opt->show_hunk_mark)
 750                         opt->output(opt, "\n", 1);
 751         } else if (opt->pre_context || opt->post_context || opt->funcbody) {
 752                 if (opt->last_shown == 0) {
 753                         if (opt->show_hunk_mark) {
 754                                 output_color(opt, "--", 2, opt->color_sep);
 755                                 opt->output(opt, "\n", 1);
 756                         }
 757                 } else if (lno > opt->last_shown + 1) {
 758                         output_color(opt, "--", 2, opt->color_sep);
 759                         opt->output(opt, "\n", 1);
 760                 }
 761         }
 762         if (opt->heading && opt->last_shown == 0) {
 763                 output_color(opt, name, strlen(name), opt->color_filename);
 764                 opt->output(opt, "\n", 1);
 765         }
 766         opt->last_shown = lno;
 767
 768         if (!opt->heading && opt->pathname) {
 769                 output_color(opt, name, strlen(name), opt->color_filename);
 770                 output_sep(opt, sign);
 771         }
 772         if (opt->linenum) {
 773                 char buf[32];
 774                 snprintf(buf, sizeof(buf), "%d", lno);
 775                 output_color(opt, buf, strlen(buf), opt->color_lineno);
 776                 output_sep(opt, sign);
 777         }
 778         if (opt->color) {
 779                 regmatch_t match;
 780                 enum grep_context ctx = GREP_CONTEXT_BODY;
 781                 int ch = *eol;
 782                 int eflags = 0;
 783
 784                 if (sign == ':')
 785                         line_color = opt->color_selected;
 786                 else if (sign == '-')
 787                         line_color = opt->color_context;
 788                 else if (sign == '=')
 789                         line_color = opt->color_function;
 790                 *eol = '\0';
 791                 while (next_match(opt, bol, eol, ctx, &match, eflags)) {
 792                         if (match.rm_so == match.rm_eo)
 793                                 break;
 794
 795                         output_color(opt, bol, match.rm_so, line_color);
 796                         output_color(opt, bol + match.rm_so,
 797                                      match.rm_eo - match.rm_so,
 798                                      opt->color_match);
 799                         bol += match.rm_eo;
 800                         rest -= match.rm_eo;
 801                         eflags = REG_NOTBOL;
 802                 }
 803                 *eol = ch;
 804         }
 805         output_color(opt, bol, rest, line_color);
 806         opt->output(opt, "\n", 1);
 807 }
 808
 809 static int match_funcname(struct grep_opt *opt, char *bol, char *eol)
 810 {
 811         xdemitconf_t *xecfg = opt->priv;
 812         if (xecfg && xecfg->find_func) {
 813                 char buf[1];
 814                 return xecfg->find_func(bol, eol - bol, buf, 1,
 815                                         xecfg->find_func_priv) >= 0;
 816         }
 817
 818         if (bol == eol)
 819                 return 0;
 820         if (isalpha(*bol) || *bol == '_' || *bol == '$')
 821                 return 1;
 822         return 0;
 823 }
 824
 825 static void show_funcname_line(struct grep_opt *opt, const char *name,
 826                                char *buf, char *bol, unsigned lno)
 827 {
 828         while (bol > buf) {
 829                 char *eol = --bol;
 830
 831                 while (bol > buf && bol[-1] != '\n')
 832                         bol--;
 833                 lno--;
 834
 835                 if (lno <= opt->last_shown)
 836                         break;
 837
 838                 if (match_funcname(opt, bol, eol)) {
 839                         show_line(opt, bol, eol, name, lno, '=');
 840                         break;
 841                 }
 842         }
 843 }
 844
 845 static void show_pre_context(struct grep_opt *opt, const char *name, char *buf,
 846                              char *bol, char *end, unsigned lno)
 847 {
 848         unsigned cur = lno, from = 1, funcname_lno = 0;
 849         int funcname_needed = !!opt->funcname;
 850
 851         if (opt->funcbody && !match_funcname(opt, bol, end))
 852                 funcname_needed = 2;
 853
 854         if (opt->pre_context < lno)
 855                 from = lno - opt->pre_context;
 856         if (from <= opt->last_shown)
 857                 from = opt->last_shown + 1;
 858
 859         /* Rewind. */
 860         while (bol > buf &&
 861                cur > (funcname_needed == 2 ? opt->last_shown + 1 : from)) {
 862                 char *eol = --bol;
 863
 864                 while (bol > buf && bol[-1] != '\n')
 865                         bol--;
 866                 cur--;
 867                 if (funcname_needed && match_funcname(opt, bol, eol)) {
 868                         funcname_lno = cur;
 869                         funcname_needed = 0;
 870                 }
 871         }
 872
 873         /* We need to look even further back to find a function signature. */
 874         if (opt->funcname && funcname_needed)
 875                 show_funcname_line(opt, name, buf, bol, cur);
 876
 877         /* Back forward. */
 878         while (cur < lno) {
 879                 char *eol = bol, sign = (cur == funcname_lno) ? '=' : '-';
 880
 881                 while (*eol != '\n')
 882                         eol++;
 883                 show_line(opt, bol, eol, name, cur, sign);
 884                 bol = eol + 1;
 885                 cur++;
 886         }
 887 }
 888
 889 static int should_lookahead(struct grep_opt *opt)
 890 {
 891         struct grep_pat *p;
 892
 893         if (opt->extended)
 894                 return 0; /* punt for too complex stuff */
 895         if (opt->invert)
 896                 return 0;
 897         for (p = opt->pattern_list; p; p = p->next) {
 898                 if (p->token != GREP_PATTERN)
 899                         return 0; /* punt for "header only" and stuff */
 900         }
 901         return 1;
 902 }
 903
 904 static int look_ahead(struct grep_opt *opt,
 905                       unsigned long *left_p,
 906                       unsigned *lno_p,
 907                       char **bol_p)
 908 {
 909         unsigned lno = *lno_p;
 910         char *bol = *bol_p;
 911         struct grep_pat *p;
 912         char *sp, *last_bol;
 913         regoff_t earliest = -1;
 914
 915         for (p = opt->pattern_list; p; p = p->next) {
 916                 int hit;
 917                 regmatch_t m;
 918
 919                 hit = patmatch(p, bol, bol + *left_p, &m, 0);
 920                 if (!hit || m.rm_so < 0 || m.rm_eo < 0)
 921                         continue;
 922                 if (earliest < 0 || m.rm_so < earliest)
 923                         earliest = m.rm_so;
 924         }
 925
 926         if (earliest < 0) {
 927                 *bol_p = bol + *left_p;
 928                 *left_p = 0;
 929                 return 1;
 930         }
 931         for (sp = bol + earliest; bol < sp && sp[-1] != '\n'; sp--)
 932                 ; /* find the beginning of the line */
 933         last_bol = sp;
 934
 935         for (sp = bol; sp < last_bol; sp++) {
 936                 if (*sp == '\n')
 937                         lno++;
 938         }
 939         *left_p -= last_bol - bol;
 940         *bol_p = last_bol;
 941         *lno_p = lno;
 942         return 0;
 943 }
 944
 945 int grep_threads_ok(const struct grep_opt *opt)
 946 {
 947         /* If this condition is true, then we may use the attribute
 948          * machinery in grep_buffer_1. The attribute code is not
 949          * thread safe, so we disable the use of threads.
 950          */
 951         if (opt->funcname && !opt->unmatch_name_only && !opt->status_only &&
 952             !opt->name_only)
 953                 return 0;
 954
 955         return 1;
 956 }
 957
 958 static void std_output(struct grep_opt *opt, const void *buf, size_t size)
 959 {
 960         fwrite(buf, size, 1, stdout);
 961 }
 962
 963 static int grep_buffer_1(struct grep_opt *opt, const char *name,
 964                          char *buf, unsigned long size, int collect_hits)
 965 {
 966         char *bol = buf;
 967         unsigned long left = size;
 968         unsigned lno = 1;
 969         unsigned last_hit = 0;
 970         int binary_match_only = 0;
 971         unsigned count = 0;
 972         int try_lookahead = 0;
 973         int show_function = 0;
 974         enum grep_context ctx = GREP_CONTEXT_HEAD;
 975         xdemitconf_t xecfg;
 976
 977         if (!opt->output)
 978                 opt->output = std_output;
 979
 980         if (opt->pre_context || opt->post_context || opt->file_break ||
 981             opt->funcbody) {
 982                 /* Show hunk marks, except for the first file. */
 983                 if (opt->last_shown)
 984                         opt->show_hunk_mark = 1;
 985                 /*
 986                  * If we're using threads then we can't easily identify
 987                  * the first file.  Always put hunk marks in that case
 988                  * and skip the very first one later in work_done().
 989                  */
 990                 if (opt->output != std_output)
 991                         opt->show_hunk_mark = 1;
 992         }
 993         opt->last_shown = 0;
 994
 995         switch (opt->binary) {
 996         case GREP_BINARY_DEFAULT:
 997                 if (buffer_is_binary(buf, size))
 998                         binary_match_only = 1;
 999                 break;
1000         case GREP_BINARY_NOMATCH:
1001                 if (buffer_is_binary(buf, size))
1002                         return 0; /* Assume unmatch */
1003                 break;
1004         case GREP_BINARY_TEXT:
1005                 break;
1006         default:
1007                 die("bug: unknown binary handling mode");
1008         }
1009
1010         memset(&xecfg, 0, sizeof(xecfg));
1011         if (opt->funcname && !opt->unmatch_name_only && !opt->status_only &&
1012             !opt->name_only && !binary_match_only && !collect_hits) {
1013                 struct userdiff_driver *drv = userdiff_find_by_path(name);
1014                 if (drv && drv->funcname.pattern) {
1015                         const struct userdiff_funcname *pe = &drv->funcname;
1016                         xdiff_set_find_func(&xecfg, pe->pattern, pe->cflags);
1017                         opt->priv = &xecfg;
1018                 }
1019         }
1020         try_lookahead = should_lookahead(opt);
1021
1022         while (left) {
1023                 char *eol, ch;
1024                 int hit;
1025
1026                 /*
1027                  * look_ahead() skips quickly to the line that possibly
1028                  * has the next hit; don't call it if we need to do
1029                  * something more than just skipping the current line
1030                  * in response to an unmatch for the current line.  E.g.
1031                  * inside a post-context window, we will show the current
1032                  * line as a context around the previous hit when it
1033                  * doesn't hit.
1034                  */
1035                 if (try_lookahead
1036                     && !(last_hit
1037                          && (show_function ||
1038                              lno <= last_hit + opt->post_context))
1039                     && look_ahead(opt, &left, &lno, &bol))
1040                         break;
1041                 eol = end_of_line(bol, &left);
1042                 ch = *eol;
1043                 *eol = 0;
1044
1045                 if ((ctx == GREP_CONTEXT_HEAD) && (eol == bol))
1046                         ctx = GREP_CONTEXT_BODY;
1047
1048                 hit = match_line(opt, bol, eol, ctx, collect_hits);
1049                 *eol = ch;
1050
1051                 if (collect_hits)
1052                         goto next_line;
1053
1054                 /* "grep -v -e foo -e bla" should list lines
1055                  * that do not have either, so inversion should
1056                  * be done outside.
1057                  */
1058                 if (opt->invert)
1059                         hit = !hit;
1060                 if (opt->unmatch_name_only) {
1061                         if (hit)
1062                                 return 0;
1063                         goto next_line;
1064                 }
1065                 if (hit) {
1066                         count++;
1067                         if (opt->status_only)
1068                                 return 1;
1069                         if (opt->name_only) {
1070                                 show_name(opt, name);
1071                                 return 1;
1072                         }
1073                         if (opt->count)
1074                                 goto next_line;
1075                         if (binary_match_only) {
1076                                 opt->output(opt, "Binary file ", 12);
1077                                 output_color(opt, name, strlen(name),
1078                                              opt->color_filename);
1079                                 opt->output(opt, " matches\n", 9);
1080                                 return 1;
1081                         }
1082                         /* Hit at this line.  If we haven't shown the
1083                          * pre-context lines, we would need to show them.
1084                          */
1085                         if (opt->pre_context || opt->funcbody)
1086                                 show_pre_context(opt, name, buf, bol, eol, lno);
1087                         else if (opt->funcname)
1088                                 show_funcname_line(opt, name, buf, bol, lno);
1089                         show_line(opt, bol, eol, name, lno, ':');
1090                         last_hit = lno;
1091                         if (opt->funcbody)
1092                                 show_function = 1;
1093                         goto next_line;
1094                 }
1095                 if (show_function && match_funcname(opt, bol, eol))
1096                         show_function = 0;
1097                 if (show_function ||
1098                     (last_hit && lno <= last_hit + opt->post_context)) {
1099                         /* If the last hit is within the post context,
1100                          * we need to show this line.
1101                          */
1102                         show_line(opt, bol, eol, name, lno, '-');
1103                 }
1104
1105         next_line:
1106                 bol = eol + 1;
1107                 if (!left)
1108                         break;
1109                 left--;
1110                 lno++;
1111         }
1112
1113         if (collect_hits)
1114                 return 0;
1115
1116         if (opt->status_only)
1117                 return 0;
1118         if (opt->unmatch_name_only) {
1119                 /* We did not see any hit, so we want to show this */
1120                 show_name(opt, name);
1121                 return 1;
1122         }
1123
1124         xdiff_clear_find_func(&xecfg);
1125         opt->priv = NULL;
1126
1127         /* NEEDSWORK:
1128          * The real "grep -c foo *.c" gives many "bar.c:0" lines,
1129          * which feels mostly useless but sometimes useful.  Maybe
1130          * make it another option?  For now suppress them.
1131          */
1132         if (opt->count && count) {
1133                 char buf[32];
1134                 output_color(opt, name, strlen(name), opt->color_filename);
1135                 output_sep(opt, ':');
1136                 snprintf(buf, sizeof(buf), "%u\n", count);
1137                 opt->output(opt, buf, strlen(buf));
1138                 return 1;
1139         }
1140         return !!last_hit;
1141 }
1142
1143 static void clr_hit_marker(struct grep_expr *x)
1144 {
1145         /* All-hit markers are meaningful only at the very top level
1146          * OR node.
1147          */
1148         while (1) {
1149                 x->hit = 0;
1150                 if (x->node != GREP_NODE_OR)
1151                         return;
1152                 x->u.binary.left->hit = 0;
1153                 x = x->u.binary.right;
1154         }
1155 }
1156
1157 static int chk_hit_marker(struct grep_expr *x)
1158 {
1159         /* Top level nodes have hit markers.  See if they all are hits */
1160         while (1) {
1161                 if (x->node != GREP_NODE_OR)
1162                         return x->hit;
1163                 if (!x->u.binary.left->hit)
1164                         return 0;
1165                 x = x->u.binary.right;
1166         }
1167 }
1168
1169 int grep_buffer(struct grep_opt *opt, const char *name, char *buf, unsigned long size)
1170 {
1171         /*
1172          * we do not have to do the two-pass grep when we do not check
1173          * buffer-wide "all-match".
1174          */
1175         if (!opt->all_match)
1176                 return grep_buffer_1(opt, name, buf, size, 0);
1177
1178         /* Otherwise the toplevel "or" terms hit a bit differently.
1179          * We first clear hit markers from them.
1180          */
1181         clr_hit_marker(opt->pattern_expression);
1182         grep_buffer_1(opt, name, buf, size, 1);
1183
1184         if (!chk_hit_marker(opt->pattern_expression))
1185                 return 0;
1186
1187         return grep_buffer_1(opt, name, buf, size, 0);
1188 }