grep.c

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