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