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->pattern_tail = p;
  15         opt->pattern_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
 188         if (opt->all_match)
 189                 opt->extended = 1;
 190
 191         for (p = opt->pattern_list; p; p = p->next) {
 192                 switch (p->token) {
 193                 case GREP_PATTERN: /* atom */
 194                 case GREP_PATTERN_HEAD:
 195                 case GREP_PATTERN_BODY:
 196                         compile_regexp(p, opt);
 197                         break;
 198                 default:
 199                         opt->extended = 1;
 200                         break;
 201                 }
 202         }
 203
 204         if (!opt->extended)
 205                 return;
 206
 207         /* Then bundle them up in an expression.
 208          * A classic recursive descent parser would do.
 209          */
 210         p = opt->pattern_list;
 211         if (p)
 212                 opt->pattern_expression = compile_pattern_expr(&p);
 213         if (p)
 214                 die("incomplete pattern expression: %s", p->pattern);
 215 }
 216
 217 static void free_pattern_expr(struct grep_expr *x)
 218 {
 219         switch (x->node) {
 220         case GREP_NODE_ATOM:
 221                 break;
 222         case GREP_NODE_NOT:
 223                 free_pattern_expr(x->u.unary);
 224                 break;
 225         case GREP_NODE_AND:
 226         case GREP_NODE_OR:
 227                 free_pattern_expr(x->u.binary.left);
 228                 free_pattern_expr(x->u.binary.right);
 229                 break;
 230         }
 231         free(x);
 232 }
 233
 234 void free_grep_patterns(struct grep_opt *opt)
 235 {
 236         struct grep_pat *p, *n;
 237
 238         for (p = opt->pattern_list; p; p = n) {
 239                 n = p->next;
 240                 switch (p->token) {
 241                 case GREP_PATTERN: /* atom */
 242                 case GREP_PATTERN_HEAD:
 243                 case GREP_PATTERN_BODY:
 244                         regfree(&p->regexp);
 245                         break;
 246                 default:
 247                         break;
 248                 }
 249                 free(p);
 250         }
 251
 252         if (!opt->extended)
 253                 return;
 254         free_pattern_expr(opt->pattern_expression);
 255 }
 256
 257 static char *end_of_line(char *cp, unsigned long *left)
 258 {
 259         unsigned long l = *left;
 260         while (l && *cp != '\n') {
 261                 l--;
 262                 cp++;
 263         }
 264         *left = l;
 265         return cp;
 266 }
 267
 268 static int word_char(char ch)
 269 {
 270         return isalnum(ch) || ch == '_';
 271 }
 272
 273 static void show_name(struct grep_opt *opt, const char *name)
 274 {
 275         opt->output(opt, name, strlen(name));
 276         opt->output(opt, opt->null_following_name ? "\0" : "\n", 1);
 277 }
 278
 279
 280 static int fixmatch(const char *pattern, char *line, int ignore_case, regmatch_t *match)
 281 {
 282         char *hit;
 283         if (ignore_case)
 284                 hit = strcasestr(line, pattern);
 285         else
 286                 hit = strstr(line, pattern);
 287
 288         if (!hit) {
 289                 match->rm_so = match->rm_eo = -1;
 290                 return REG_NOMATCH;
 291         }
 292         else {
 293                 match->rm_so = hit - line;
 294                 match->rm_eo = match->rm_so + strlen(pattern);
 295                 return 0;
 296         }
 297 }
 298
 299 static int strip_timestamp(char *bol, char **eol_p)
 300 {
 301         char *eol = *eol_p;
 302         int ch;
 303
 304         while (bol < --eol) {
 305                 if (*eol != '>')
 306                         continue;
 307                 *eol_p = ++eol;
 308                 ch = *eol;
 309                 *eol = '\0';
 310                 return ch;
 311         }
 312         return 0;
 313 }
 314
 315 static struct {
 316         const char *field;
 317         size_t len;
 318 } header_field[] = {
 319         { "author ", 7 },
 320         { "committer ", 10 },
 321 };
 322
 323 static int match_one_pattern(struct grep_pat *p, char *bol, char *eol,
 324                              enum grep_context ctx,
 325                              regmatch_t *pmatch, int eflags)
 326 {
 327         int hit = 0;
 328         int saved_ch = 0;
 329         const char *start = bol;
 330
 331         if ((p->token != GREP_PATTERN) &&
 332             ((p->token == GREP_PATTERN_HEAD) != (ctx == GREP_CONTEXT_HEAD)))
 333                 return 0;
 334
 335         if (p->token == GREP_PATTERN_HEAD) {
 336                 const char *field;
 337                 size_t len;
 338                 assert(p->field < ARRAY_SIZE(header_field));
 339                 field = header_field[p->field].field;
 340                 len = header_field[p->field].len;
 341                 if (strncmp(bol, field, len))
 342                         return 0;
 343                 bol += len;
 344                 saved_ch = strip_timestamp(bol, &eol);
 345         }
 346
 347  again:
 348         if (p->fixed)
 349                 hit = !fixmatch(p->pattern, bol, p->ignore_case, pmatch);
 350         else
 351                 hit = !regexec(&p->regexp, bol, 1, pmatch, eflags);
 352
 353         if (hit && p->word_regexp) {
 354                 if ((pmatch[0].rm_so < 0) ||
 355                     (eol - bol) < pmatch[0].rm_so ||
 356                     (pmatch[0].rm_eo < 0) ||
 357                     (eol - bol) < pmatch[0].rm_eo)
 358                         die("regexp returned nonsense");
 359
 360                 /* Match beginning must be either beginning of the
 361                  * line, or at word boundary (i.e. the last char must
 362                  * not be a word char).  Similarly, match end must be
 363                  * either end of the line, or at word boundary
 364                  * (i.e. the next char must not be a word char).
 365                  */
 366                 if ( ((pmatch[0].rm_so == 0) ||
 367                       !word_char(bol[pmatch[0].rm_so-1])) &&
 368                      ((pmatch[0].rm_eo == (eol-bol)) ||
 369                       !word_char(bol[pmatch[0].rm_eo])) )
 370                         ;
 371                 else
 372                         hit = 0;
 373
 374                 /* Words consist of at least one character. */
 375                 if (pmatch->rm_so == pmatch->rm_eo)
 376                         hit = 0;
 377
 378                 if (!hit && pmatch[0].rm_so + bol + 1 < eol) {
 379                         /* There could be more than one match on the
 380                          * line, and the first match might not be
 381                          * strict word match.  But later ones could be!
 382                          * Forward to the next possible start, i.e. the
 383                          * next position following a non-word char.
 384                          */
 385                         bol = pmatch[0].rm_so + bol + 1;
 386                         while (word_char(bol[-1]) && bol < eol)
 387                                 bol++;
 388                         eflags |= REG_NOTBOL;
 389                         if (bol < eol)
 390                                 goto again;
 391                 }
 392         }
 393         if (p->token == GREP_PATTERN_HEAD && saved_ch)
 394                 *eol = saved_ch;
 395         if (hit) {
 396                 pmatch[0].rm_so += bol - start;
 397                 pmatch[0].rm_eo += bol - start;
 398         }
 399         return hit;
 400 }
 401
 402 static int match_expr_eval(struct grep_expr *x, char *bol, char *eol,
 403                            enum grep_context ctx, int collect_hits)
 404 {
 405         int h = 0;
 406         regmatch_t match;
 407
 408         if (!x)
 409                 die("Not a valid grep expression");
 410         switch (x->node) {
 411         case GREP_NODE_ATOM:
 412                 h = match_one_pattern(x->u.atom, bol, eol, ctx, &match, 0);
 413                 break;
 414         case GREP_NODE_NOT:
 415                 h = !match_expr_eval(x->u.unary, bol, eol, ctx, 0);
 416                 break;
 417         case GREP_NODE_AND:
 418                 if (!match_expr_eval(x->u.binary.left, bol, eol, ctx, 0))
 419                         return 0;
 420                 h = match_expr_eval(x->u.binary.right, bol, eol, ctx, 0);
 421                 break;
 422         case GREP_NODE_OR:
 423                 if (!collect_hits)
 424                         return (match_expr_eval(x->u.binary.left,
 425                                                 bol, eol, ctx, 0) ||
 426                                 match_expr_eval(x->u.binary.right,
 427                                                 bol, eol, ctx, 0));
 428                 h = match_expr_eval(x->u.binary.left, bol, eol, ctx, 0);
 429                 x->u.binary.left->hit |= h;
 430                 h |= match_expr_eval(x->u.binary.right, bol, eol, ctx, 1);
 431                 break;
 432         default:
 433                 die("Unexpected node type (internal error) %d", x->node);
 434         }
 435         if (collect_hits)
 436                 x->hit |= h;
 437         return h;
 438 }
 439
 440 static int match_expr(struct grep_opt *opt, char *bol, char *eol,
 441                       enum grep_context ctx, int collect_hits)
 442 {
 443         struct grep_expr *x = opt->pattern_expression;
 444         return match_expr_eval(x, bol, eol, ctx, collect_hits);
 445 }
 446
 447 static int match_line(struct grep_opt *opt, char *bol, char *eol,
 448                       enum grep_context ctx, int collect_hits)
 449 {
 450         struct grep_pat *p;
 451         regmatch_t match;
 452
 453         if (opt->extended)
 454                 return match_expr(opt, bol, eol, ctx, collect_hits);
 455
 456         /* we do not call with collect_hits without being extended */
 457         for (p = opt->pattern_list; p; p = p->next) {
 458                 if (match_one_pattern(p, bol, eol, ctx, &match, 0))
 459                         return 1;
 460         }
 461         return 0;
 462 }
 463
 464 static int match_next_pattern(struct grep_pat *p, char *bol, char *eol,
 465                               enum grep_context ctx,
 466                               regmatch_t *pmatch, int eflags)
 467 {
 468         regmatch_t match;
 469
 470         if (!match_one_pattern(p, bol, eol, ctx, &match, eflags))
 471                 return 0;
 472         if (match.rm_so < 0 || match.rm_eo < 0)
 473                 return 0;
 474         if (pmatch->rm_so >= 0 && pmatch->rm_eo >= 0) {
 475                 if (match.rm_so > pmatch->rm_so)
 476                         return 1;
 477                 if (match.rm_so == pmatch->rm_so && match.rm_eo < pmatch->rm_eo)
 478                         return 1;
 479         }
 480         pmatch->rm_so = match.rm_so;
 481         pmatch->rm_eo = match.rm_eo;
 482         return 1;
 483 }
 484
 485 static int next_match(struct grep_opt *opt, char *bol, char *eol,
 486                       enum grep_context ctx, regmatch_t *pmatch, int eflags)
 487 {
 488         struct grep_pat *p;
 489         int hit = 0;
 490
 491         pmatch->rm_so = pmatch->rm_eo = -1;
 492         if (bol < eol) {
 493                 for (p = opt->pattern_list; p; p = p->next) {
 494                         switch (p->token) {
 495                         case GREP_PATTERN: /* atom */
 496                         case GREP_PATTERN_HEAD:
 497                         case GREP_PATTERN_BODY:
 498                                 hit |= match_next_pattern(p, bol, eol, ctx,
 499                                                           pmatch, eflags);
 500                                 break;
 501                         default:
 502                                 break;
 503                         }
 504                 }
 505         }
 506         return hit;
 507 }
 508
 509 static void show_line(struct grep_opt *opt, char *bol, char *eol,
 510                       const char *name, unsigned lno, char sign)
 511 {
 512         int rest = eol - bol;
 513         char sign_str[1];
 514
 515         sign_str[0] = sign;
 516         if (opt->pre_context || opt->post_context) {
 517                 if (opt->last_shown == 0) {
 518                         if (opt->show_hunk_mark)
 519                                 opt->output(opt, "--\n", 3);
 520                         else
 521                                 opt->show_hunk_mark = 1;
 522                 } else if (lno > opt->last_shown + 1)
 523                         opt->output(opt, "--\n", 3);
 524         }
 525         opt->last_shown = lno;
 526
 527         if (opt->null_following_name)
 528                 sign_str[0] = '\0';
 529         if (opt->pathname) {
 530                 opt->output(opt, name, strlen(name));
 531                 opt->output(opt, sign_str, 1);
 532         }
 533         if (opt->linenum) {
 534                 char buf[32];
 535                 snprintf(buf, sizeof(buf), "%d", lno);
 536                 opt->output(opt, buf, strlen(buf));
 537                 opt->output(opt, sign_str, 1);
 538         }
 539         if (opt->color) {
 540                 regmatch_t match;
 541                 enum grep_context ctx = GREP_CONTEXT_BODY;
 542                 int ch = *eol;
 543                 int eflags = 0;
 544
 545                 *eol = '\0';
 546                 while (next_match(opt, bol, eol, ctx, &match, eflags)) {
 547                         if (match.rm_so == match.rm_eo)
 548                                 break;
 549
 550                         opt->output(opt, bol, match.rm_so);
 551                         opt->output(opt, opt->color_match,
 552                                     strlen(opt->color_match));
 553                         opt->output(opt, bol + match.rm_so,
 554                                     (int)(match.rm_eo - match.rm_so));
 555                         opt->output(opt, GIT_COLOR_RESET,
 556                                     strlen(GIT_COLOR_RESET));
 557                         bol += match.rm_eo;
 558                         rest -= match.rm_eo;
 559                         eflags = REG_NOTBOL;
 560                 }
 561                 *eol = ch;
 562         }
 563         opt->output(opt, bol, rest);
 564         opt->output(opt, "\n", 1);
 565 }
 566
 567 static int match_funcname(struct grep_opt *opt, char *bol, char *eol)
 568 {
 569         xdemitconf_t *xecfg = opt->priv;
 570         if (xecfg && xecfg->find_func) {
 571                 char buf[1];
 572                 return xecfg->find_func(bol, eol - bol, buf, 1,
 573                                         xecfg->find_func_priv) >= 0;
 574         }
 575
 576         if (bol == eol)
 577                 return 0;
 578         if (isalpha(*bol) || *bol == '_' || *bol == '$')
 579                 return 1;
 580         return 0;
 581 }
 582
 583 static void show_funcname_line(struct grep_opt *opt, const char *name,
 584                                char *buf, char *bol, unsigned lno)
 585 {
 586         while (bol > buf) {
 587                 char *eol = --bol;
 588
 589                 while (bol > buf && bol[-1] != '\n')
 590                         bol--;
 591                 lno--;
 592
 593                 if (lno <= opt->last_shown)
 594                         break;
 595
 596                 if (match_funcname(opt, bol, eol)) {
 597                         show_line(opt, bol, eol, name, lno, '=');
 598                         break;
 599                 }
 600         }
 601 }
 602
 603 static void show_pre_context(struct grep_opt *opt, const char *name, char *buf,
 604                              char *bol, unsigned lno)
 605 {
 606         unsigned cur = lno, from = 1, funcname_lno = 0;
 607         int funcname_needed = opt->funcname;
 608
 609         if (opt->pre_context < lno)
 610                 from = lno - opt->pre_context;
 611         if (from <= opt->last_shown)
 612                 from = opt->last_shown + 1;
 613
 614         /* Rewind. */
 615         while (bol > buf && cur > from) {
 616                 char *eol = --bol;
 617
 618                 while (bol > buf && bol[-1] != '\n')
 619                         bol--;
 620                 cur--;
 621                 if (funcname_needed && match_funcname(opt, bol, eol)) {
 622                         funcname_lno = cur;
 623                         funcname_needed = 0;
 624                 }
 625         }
 626
 627         /* We need to look even further back to find a function signature. */
 628         if (opt->funcname && funcname_needed)
 629                 show_funcname_line(opt, name, buf, bol, cur);
 630
 631         /* Back forward. */
 632         while (cur < lno) {
 633                 char *eol = bol, sign = (cur == funcname_lno) ? '=' : '-';
 634
 635                 while (*eol != '\n')
 636                         eol++;
 637                 show_line(opt, bol, eol, name, cur, sign);
 638                 bol = eol + 1;
 639                 cur++;
 640         }
 641 }
 642
 643 static int should_lookahead(struct grep_opt *opt)
 644 {
 645         struct grep_pat *p;
 646
 647         if (opt->extended)
 648                 return 0; /* punt for too complex stuff */
 649         if (opt->invert)
 650                 return 0;
 651         for (p = opt->pattern_list; p; p = p->next) {
 652                 if (p->token != GREP_PATTERN)
 653                         return 0; /* punt for "header only" and stuff */
 654         }
 655         return 1;
 656 }
 657
 658 static int look_ahead(struct grep_opt *opt,
 659                       unsigned long *left_p,
 660                       unsigned *lno_p,
 661                       char **bol_p)
 662 {
 663         unsigned lno = *lno_p;
 664         char *bol = *bol_p;
 665         struct grep_pat *p;
 666         char *sp, *last_bol;
 667         regoff_t earliest = -1;
 668
 669         for (p = opt->pattern_list; p; p = p->next) {
 670                 int hit;
 671                 regmatch_t m;
 672
 673                 if (p->fixed)
 674                         hit = !fixmatch(p->pattern, bol, p->ignore_case, &m);
 675                 else {
 676 #ifdef REG_STARTEND
 677                         m.rm_so = 0;
 678                         m.rm_eo = *left_p;
 679                         hit = !regexec(&p->regexp, bol, 1, &m, REG_STARTEND);
 680 #else
 681                         hit = !regexec(&p->regexp, bol, 1, &m, 0);
 682 #endif
 683                 }
 684                 if (!hit || m.rm_so < 0 || m.rm_eo < 0)
 685                         continue;
 686                 if (earliest < 0 || m.rm_so < earliest)
 687                         earliest = m.rm_so;
 688         }
 689
 690         if (earliest < 0) {
 691                 *bol_p = bol + *left_p;
 692                 *left_p = 0;
 693                 return 1;
 694         }
 695         for (sp = bol + earliest; bol < sp && sp[-1] != '\n'; sp--)
 696                 ; /* find the beginning of the line */
 697         last_bol = sp;
 698
 699         for (sp = bol; sp < last_bol; sp++) {
 700                 if (*sp == '\n')
 701                         lno++;
 702         }
 703         *left_p -= last_bol - bol;
 704         *bol_p = last_bol;
 705         *lno_p = lno;
 706         return 0;
 707 }
 708
 709 int grep_threads_ok(const struct grep_opt *opt)
 710 {
 711         /* If this condition is true, then we may use the attribute
 712          * machinery in grep_buffer_1. The attribute code is not
 713          * thread safe, so we disable the use of threads.
 714          */
 715         if (opt->funcname && !opt->unmatch_name_only && !opt->status_only &&
 716             !opt->name_only)
 717                 return 0;
 718
 719         /* If we are showing hunk marks, we should not do it for the
 720          * first match. The synchronization problem we get for this
 721          * constraint is not yet solved, so we disable threading in
 722          * this case.
 723          */
 724         if (opt->pre_context || opt->post_context)
 725                 return 0;
 726
 727         return 1;
 728 }
 729
 730 static void std_output(struct grep_opt *opt, const void *buf, size_t size)
 731 {
 732         fwrite(buf, size, 1, stdout);
 733 }
 734
 735 static int grep_buffer_1(struct grep_opt *opt, const char *name,
 736                          char *buf, unsigned long size, int collect_hits)
 737 {
 738         char *bol = buf;
 739         unsigned long left = size;
 740         unsigned lno = 1;
 741         unsigned last_hit = 0;
 742         int binary_match_only = 0;
 743         unsigned count = 0;
 744         int try_lookahead = 0;
 745         enum grep_context ctx = GREP_CONTEXT_HEAD;
 746         xdemitconf_t xecfg;
 747
 748         opt->last_shown = 0;
 749
 750         if (!opt->output)
 751                 opt->output = std_output;
 752
 753         if (buffer_is_binary(buf, size)) {
 754                 switch (opt->binary) {
 755                 case GREP_BINARY_DEFAULT:
 756                         binary_match_only = 1;
 757                         break;
 758                 case GREP_BINARY_NOMATCH:
 759                         return 0; /* Assume unmatch */
 760                         break;
 761                 default:
 762                         break;
 763                 }
 764         }
 765
 766         memset(&xecfg, 0, sizeof(xecfg));
 767         if (opt->funcname && !opt->unmatch_name_only && !opt->status_only &&
 768             !opt->name_only && !binary_match_only && !collect_hits) {
 769                 struct userdiff_driver *drv = userdiff_find_by_path(name);
 770                 if (drv && drv->funcname.pattern) {
 771                         const struct userdiff_funcname *pe = &drv->funcname;
 772                         xdiff_set_find_func(&xecfg, pe->pattern, pe->cflags);
 773                         opt->priv = &xecfg;
 774                 }
 775         }
 776         try_lookahead = should_lookahead(opt);
 777
 778         while (left) {
 779                 char *eol, ch;
 780                 int hit;
 781
 782                 /*
 783                  * look_ahead() skips quicly to the line that possibly
 784                  * has the next hit; don't call it if we need to do
 785                  * something more than just skipping the current line
 786                  * in response to an unmatch for the current line.  E.g.
 787                  * inside a post-context window, we will show the current
 788                  * line as a context around the previous hit when it
 789                  * doesn't hit.
 790                  */
 791                 if (try_lookahead
 792                     && !(last_hit
 793                          && lno <= last_hit + opt->post_context)
 794                     && look_ahead(opt, &left, &lno, &bol))
 795                         break;
 796                 eol = end_of_line(bol, &left);
 797                 ch = *eol;
 798                 *eol = 0;
 799
 800                 if ((ctx == GREP_CONTEXT_HEAD) && (eol == bol))
 801                         ctx = GREP_CONTEXT_BODY;
 802
 803                 hit = match_line(opt, bol, eol, ctx, collect_hits);
 804                 *eol = ch;
 805
 806                 if (collect_hits)
 807                         goto next_line;
 808
 809                 /* "grep -v -e foo -e bla" should list lines
 810                  * that do not have either, so inversion should
 811                  * be done outside.
 812                  */
 813                 if (opt->invert)
 814                         hit = !hit;
 815                 if (opt->unmatch_name_only) {
 816                         if (hit)
 817                                 return 0;
 818                         goto next_line;
 819                 }
 820                 if (hit) {
 821                         count++;
 822                         if (opt->status_only)
 823                                 return 1;
 824                         if (binary_match_only) {
 825                                 opt->output(opt, "Binary file ", 12);
 826                                 opt->output(opt, name, strlen(name));
 827                                 opt->output(opt, " matches\n", 9);
 828                                 return 1;
 829                         }
 830                         if (opt->name_only) {
 831                                 show_name(opt, name);
 832                                 return 1;
 833                         }
 834                         /* Hit at this line.  If we haven't shown the
 835                          * pre-context lines, we would need to show them.
 836                          * When asked to do "count", this still show
 837                          * the context which is nonsense, but the user
 838                          * deserves to get that ;-).
 839                          */
 840                         if (opt->pre_context)
 841                                 show_pre_context(opt, name, buf, bol, lno);
 842                         else if (opt->funcname)
 843                                 show_funcname_line(opt, name, buf, bol, lno);
 844                         if (!opt->count)
 845                                 show_line(opt, bol, eol, name, lno, ':');
 846                         last_hit = lno;
 847                 }
 848                 else if (last_hit &&
 849                          lno <= last_hit + opt->post_context) {
 850                         /* If the last hit is within the post context,
 851                          * we need to show this line.
 852                          */
 853                         show_line(opt, bol, eol, name, lno, '-');
 854                 }
 855
 856         next_line:
 857                 bol = eol + 1;
 858                 if (!left)
 859                         break;
 860                 left--;
 861                 lno++;
 862         }
 863
 864         if (collect_hits)
 865                 return 0;
 866
 867         if (opt->status_only)
 868                 return 0;
 869         if (opt->unmatch_name_only) {
 870                 /* We did not see any hit, so we want to show this */
 871                 show_name(opt, name);
 872                 return 1;
 873         }
 874
 875         xdiff_clear_find_func(&xecfg);
 876         opt->priv = NULL;
 877
 878         /* NEEDSWORK:
 879          * The real "grep -c foo *.c" gives many "bar.c:0" lines,
 880          * which feels mostly useless but sometimes useful.  Maybe
 881          * make it another option?  For now suppress them.
 882          */
 883         if (opt->count && count) {
 884                 char buf[32];
 885                 opt->output(opt, name, strlen(name));
 886                 snprintf(buf, sizeof(buf), "%c%u\n",
 887                          opt->null_following_name ? '\0' : ':', count);
 888                 opt->output(opt, buf, strlen(buf));
 889         }
 890         return !!last_hit;
 891 }
 892
 893 static void clr_hit_marker(struct grep_expr *x)
 894 {
 895         /* All-hit markers are meaningful only at the very top level
 896          * OR node.
 897          */
 898         while (1) {
 899                 x->hit = 0;
 900                 if (x->node != GREP_NODE_OR)
 901                         return;
 902                 x->u.binary.left->hit = 0;
 903                 x = x->u.binary.right;
 904         }
 905 }
 906
 907 static int chk_hit_marker(struct grep_expr *x)
 908 {
 909         /* Top level nodes have hit markers.  See if they all are hits */
 910         while (1) {
 911                 if (x->node != GREP_NODE_OR)
 912                         return x->hit;
 913                 if (!x->u.binary.left->hit)
 914                         return 0;
 915                 x = x->u.binary.right;
 916         }
 917 }
 918
 919 int grep_buffer(struct grep_opt *opt, const char *name, char *buf, unsigned long size)
 920 {
 921         /*
 922          * we do not have to do the two-pass grep when we do not check
 923          * buffer-wide "all-match".
 924          */
 925         if (!opt->all_match)
 926                 return grep_buffer_1(opt, name, buf, size, 0);
 927
 928         /* Otherwise the toplevel "or" terms hit a bit differently.
 929          * We first clear hit markers from them.
 930          */
 931         clr_hit_marker(opt->pattern_expression);
 932         grep_buffer_1(opt, name, buf, size, 1);
 933
 934         if (!chk_hit_marker(opt->pattern_expression))
 935                 return 0;
 936
 937         return grep_buffer_1(opt, name, buf, size, 0);
 938 }