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