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