grep.c

   1 #include "cache.h"
   2 #include "grep.h"
   3 #include "xdiff-interface.h"
   4
   5 void append_header_grep_pattern(struct grep_opt *opt, enum grep_header_field field, const char *pat)
   6 {
   7         struct grep_pat *p = xcalloc(1, sizeof(*p));
   8         p->pattern = pat;
   9         p->origin = "header";
  10         p->no = 0;
  11         p->token = GREP_PATTERN_HEAD;
  12         p->field = field;
  13         *opt->pattern_tail = p;
  14         opt->pattern_tail = &p->next;
  15         p->next = NULL;
  16 }
  17
  18 void append_grep_pattern(struct grep_opt *opt, const char *pat,
  19                          const char *origin, int no, enum grep_pat_token t)
  20 {
  21         struct grep_pat *p = xcalloc(1, sizeof(*p));
  22         p->pattern = pat;
  23         p->origin = origin;
  24         p->no = no;
  25         p->token = t;
  26         *opt->pattern_tail = p;
  27         opt->pattern_tail = &p->next;
  28         p->next = NULL;
  29 }
  30
  31 static int is_fixed(const char *s)
  32 {
  33         while (*s && !is_regex_special(*s))
  34                 s++;
  35         return !*s;
  36 }
  37
  38 static void compile_regexp(struct grep_pat *p, struct grep_opt *opt)
  39 {
  40         int err;
  41
  42         p->word_regexp = opt->word_regexp;
  43
  44         if (opt->fixed || is_fixed(p->pattern))
  45                 p->fixed = 1;
  46         if (opt->regflags & REG_ICASE)
  47                 p->fixed = 0;
  48         if (p->fixed)
  49                 return;
  50
  51         err = regcomp(&p->regexp, p->pattern, opt->regflags);
  52         if (err) {
  53                 char errbuf[1024];
  54                 char where[1024];
  55                 if (p->no)
  56                         sprintf(where, "In '%s' at %d, ",
  57                                 p->origin, p->no);
  58                 else if (p->origin)
  59                         sprintf(where, "%s, ", p->origin);
  60                 else
  61                         where[0] = 0;
  62                 regerror(err, &p->regexp, errbuf, 1024);
  63                 regfree(&p->regexp);
  64                 die("%s'%s': %s", where, p->pattern, errbuf);
  65         }
  66 }
  67
  68 static struct grep_expr *compile_pattern_or(struct grep_pat **);
  69 static struct grep_expr *compile_pattern_atom(struct grep_pat **list)
  70 {
  71         struct grep_pat *p;
  72         struct grep_expr *x;
  73
  74         p = *list;
  75         switch (p->token) {
  76         case GREP_PATTERN: /* atom */
  77         case GREP_PATTERN_HEAD:
  78         case GREP_PATTERN_BODY:
  79                 x = xcalloc(1, sizeof (struct grep_expr));
  80                 x->node = GREP_NODE_ATOM;
  81                 x->u.atom = p;
  82                 *list = p->next;
  83                 return x;
  84         case GREP_OPEN_PAREN:
  85                 *list = p->next;
  86                 x = compile_pattern_or(list);
  87                 if (!x)
  88                         return NULL;
  89                 if (!*list || (*list)->token != GREP_CLOSE_PAREN)
  90                         die("unmatched parenthesis");
  91                 *list = (*list)->next;
  92                 return x;
  93         default:
  94                 return NULL;
  95         }
  96 }
  97
  98 static struct grep_expr *compile_pattern_not(struct grep_pat **list)
  99 {
 100         struct grep_pat *p;
 101         struct grep_expr *x;
 102
 103         p = *list;
 104         switch (p->token) {
 105         case GREP_NOT:
 106                 if (!p->next)
 107                         die("--not not followed by pattern expression");
 108                 *list = p->next;
 109                 x = xcalloc(1, sizeof (struct grep_expr));
 110                 x->node = GREP_NODE_NOT;
 111                 x->u.unary = compile_pattern_not(list);
 112                 if (!x->u.unary)
 113                         die("--not followed by non pattern expression");
 114                 return x;
 115         default:
 116                 return compile_pattern_atom(list);
 117         }
 118 }
 119
 120 static struct grep_expr *compile_pattern_and(struct grep_pat **list)
 121 {
 122         struct grep_pat *p;
 123         struct grep_expr *x, *y, *z;
 124
 125         x = compile_pattern_not(list);
 126         p = *list;
 127         if (p && p->token == GREP_AND) {
 128                 if (!p->next)
 129                         die("--and not followed by pattern expression");
 130                 *list = p->next;
 131                 y = compile_pattern_and(list);
 132                 if (!y)
 133                         die("--and not followed by pattern expression");
 134                 z = xcalloc(1, sizeof (struct grep_expr));
 135                 z->node = GREP_NODE_AND;
 136                 z->u.binary.left = x;
 137                 z->u.binary.right = y;
 138                 return z;
 139         }
 140         return x;
 141 }
 142
 143 static struct grep_expr *compile_pattern_or(struct grep_pat **list)
 144 {
 145         struct grep_pat *p;
 146         struct grep_expr *x, *y, *z;
 147
 148         x = compile_pattern_and(list);
 149         p = *list;
 150         if (x && p && p->token != GREP_CLOSE_PAREN) {
 151                 y = compile_pattern_or(list);
 152                 if (!y)
 153                         die("not a pattern expression %s", p->pattern);
 154                 z = xcalloc(1, sizeof (struct grep_expr));
 155                 z->node = GREP_NODE_OR;
 156                 z->u.binary.left = x;
 157                 z->u.binary.right = y;
 158                 return z;
 159         }
 160         return x;
 161 }
 162
 163 static struct grep_expr *compile_pattern_expr(struct grep_pat **list)
 164 {
 165         return compile_pattern_or(list);
 166 }
 167
 168 void compile_grep_patterns(struct grep_opt *opt)
 169 {
 170         struct grep_pat *p;
 171
 172         if (opt->all_match)
 173                 opt->extended = 1;
 174
 175         for (p = opt->pattern_list; p; p = p->next) {
 176                 switch (p->token) {
 177                 case GREP_PATTERN: /* atom */
 178                 case GREP_PATTERN_HEAD:
 179                 case GREP_PATTERN_BODY:
 180                         compile_regexp(p, opt);
 181                         break;
 182                 default:
 183                         opt->extended = 1;
 184                         break;
 185                 }
 186         }
 187
 188         if (!opt->extended)
 189                 return;
 190
 191         /* Then bundle them up in an expression.
 192          * A classic recursive descent parser would do.
 193          */
 194         p = opt->pattern_list;
 195         if (p)
 196                 opt->pattern_expression = compile_pattern_expr(&p);
 197         if (p)
 198                 die("incomplete pattern expression: %s", p->pattern);
 199 }
 200
 201 static void free_pattern_expr(struct grep_expr *x)
 202 {
 203         switch (x->node) {
 204         case GREP_NODE_ATOM:
 205                 break;
 206         case GREP_NODE_NOT:
 207                 free_pattern_expr(x->u.unary);
 208                 break;
 209         case GREP_NODE_AND:
 210         case GREP_NODE_OR:
 211                 free_pattern_expr(x->u.binary.left);
 212                 free_pattern_expr(x->u.binary.right);
 213                 break;
 214         }
 215         free(x);
 216 }
 217
 218 void free_grep_patterns(struct grep_opt *opt)
 219 {
 220         struct grep_pat *p, *n;
 221
 222         for (p = opt->pattern_list; p; p = n) {
 223                 n = p->next;
 224                 switch (p->token) {
 225                 case GREP_PATTERN: /* atom */
 226                 case GREP_PATTERN_HEAD:
 227                 case GREP_PATTERN_BODY:
 228                         regfree(&p->regexp);
 229                         break;
 230                 default:
 231                         break;
 232                 }
 233                 free(p);
 234         }
 235
 236         if (!opt->extended)
 237                 return;
 238         free_pattern_expr(opt->pattern_expression);
 239 }
 240
 241 static char *end_of_line(char *cp, unsigned long *left)
 242 {
 243         unsigned long l = *left;
 244         while (l && *cp != '\n') {
 245                 l--;
 246                 cp++;
 247         }
 248         *left = l;
 249         return cp;
 250 }
 251
 252 static int word_char(char ch)
 253 {
 254         return isalnum(ch) || ch == '_';
 255 }
 256
 257 static void show_name(struct grep_opt *opt, const char *name)
 258 {
 259         printf("%s%c", name, opt->null_following_name ? '\0' : '\n');
 260 }
 261
 262 static int fixmatch(const char *pattern, char *line, regmatch_t *match)
 263 {
 264         char *hit = strstr(line, pattern);
 265         if (!hit) {
 266                 match->rm_so = match->rm_eo = -1;
 267                 return REG_NOMATCH;
 268         }
 269         else {
 270                 match->rm_so = hit - line;
 271                 match->rm_eo = match->rm_so + strlen(pattern);
 272                 return 0;
 273         }
 274 }
 275
 276 static int strip_timestamp(char *bol, char **eol_p)
 277 {
 278         char *eol = *eol_p;
 279         int ch;
 280
 281         while (bol < --eol) {
 282                 if (*eol != '>')
 283                         continue;
 284                 *eol_p = ++eol;
 285                 ch = *eol;
 286                 *eol = '\0';
 287                 return ch;
 288         }
 289         return 0;
 290 }
 291
 292 static struct {
 293         const char *field;
 294         size_t len;
 295 } header_field[] = {
 296         { "author ", 7 },
 297         { "committer ", 10 },
 298 };
 299
 300 static int match_one_pattern(struct grep_pat *p, char *bol, char *eol,
 301                              enum grep_context ctx,
 302                              regmatch_t *pmatch, int eflags)
 303 {
 304         int hit = 0;
 305         int saved_ch = 0;
 306
 307         if ((p->token != GREP_PATTERN) &&
 308             ((p->token == GREP_PATTERN_HEAD) != (ctx == GREP_CONTEXT_HEAD)))
 309                 return 0;
 310
 311         if (p->token == GREP_PATTERN_HEAD) {
 312                 const char *field;
 313                 size_t len;
 314                 assert(p->field < ARRAY_SIZE(header_field));
 315                 field = header_field[p->field].field;
 316                 len = header_field[p->field].len;
 317                 if (strncmp(bol, field, len))
 318                         return 0;
 319                 bol += len;
 320                 saved_ch = strip_timestamp(bol, &eol);
 321         }
 322
 323  again:
 324         if (p->fixed)
 325                 hit = !fixmatch(p->pattern, bol, pmatch);
 326         else
 327                 hit = !regexec(&p->regexp, bol, 1, pmatch, eflags);
 328
 329         if (hit && p->word_regexp) {
 330                 if ((pmatch[0].rm_so < 0) ||
 331                     (eol - bol) <= pmatch[0].rm_so ||
 332                     (pmatch[0].rm_eo < 0) ||
 333                     (eol - bol) < pmatch[0].rm_eo)
 334                         die("regexp returned nonsense");
 335
 336                 /* Match beginning must be either beginning of the
 337                  * line, or at word boundary (i.e. the last char must
 338                  * not be a word char).  Similarly, match end must be
 339                  * either end of the line, or at word boundary
 340                  * (i.e. the next char must not be a word char).
 341                  */
 342                 if ( ((pmatch[0].rm_so == 0) ||
 343                       !word_char(bol[pmatch[0].rm_so-1])) &&
 344                      ((pmatch[0].rm_eo == (eol-bol)) ||
 345                       !word_char(bol[pmatch[0].rm_eo])) )
 346                         ;
 347                 else
 348                         hit = 0;
 349
 350                 if (!hit && pmatch[0].rm_so + bol + 1 < eol) {
 351                         /* There could be more than one match on the
 352                          * line, and the first match might not be
 353                          * strict word match.  But later ones could be!
 354                          * Forward to the next possible start, i.e. the
 355                          * next position following a non-word char.
 356                          */
 357                         bol = pmatch[0].rm_so + bol + 1;
 358                         while (word_char(bol[-1]) && bol < eol)
 359                                 bol++;
 360                         if (bol < eol)
 361                                 goto again;
 362                 }
 363         }
 364         if (p->token == GREP_PATTERN_HEAD && saved_ch)
 365                 *eol = saved_ch;
 366         return hit;
 367 }
 368
 369 static int match_expr_eval(struct grep_expr *x, char *bol, char *eol,
 370                            enum grep_context ctx, int collect_hits)
 371 {
 372         int h = 0;
 373         regmatch_t match;
 374
 375         switch (x->node) {
 376         case GREP_NODE_ATOM:
 377                 h = match_one_pattern(x->u.atom, bol, eol, ctx, &match, 0);
 378                 break;
 379         case GREP_NODE_NOT:
 380                 h = !match_expr_eval(x->u.unary, bol, eol, ctx, 0);
 381                 break;
 382         case GREP_NODE_AND:
 383                 if (!match_expr_eval(x->u.binary.left, bol, eol, ctx, 0))
 384                         return 0;
 385                 h = match_expr_eval(x->u.binary.right, bol, eol, ctx, 0);
 386                 break;
 387         case GREP_NODE_OR:
 388                 if (!collect_hits)
 389                         return (match_expr_eval(x->u.binary.left,
 390                                                 bol, eol, ctx, 0) ||
 391                                 match_expr_eval(x->u.binary.right,
 392                                                 bol, eol, ctx, 0));
 393                 h = match_expr_eval(x->u.binary.left, bol, eol, ctx, 0);
 394                 x->u.binary.left->hit |= h;
 395                 h |= match_expr_eval(x->u.binary.right, bol, eol, ctx, 1);
 396                 break;
 397         default:
 398                 die("Unexpected node type (internal error) %d", x->node);
 399         }
 400         if (collect_hits)
 401                 x->hit |= h;
 402         return h;
 403 }
 404
 405 static int match_expr(struct grep_opt *opt, char *bol, char *eol,
 406                       enum grep_context ctx, int collect_hits)
 407 {
 408         struct grep_expr *x = opt->pattern_expression;
 409         return match_expr_eval(x, bol, eol, ctx, collect_hits);
 410 }
 411
 412 static int match_line(struct grep_opt *opt, char *bol, char *eol,
 413                       enum grep_context ctx, int collect_hits)
 414 {
 415         struct grep_pat *p;
 416         regmatch_t match;
 417
 418         if (opt->extended)
 419                 return match_expr(opt, bol, eol, ctx, collect_hits);
 420
 421         /* we do not call with collect_hits without being extended */
 422         for (p = opt->pattern_list; p; p = p->next) {
 423                 if (match_one_pattern(p, bol, eol, ctx, &match, 0))
 424                         return 1;
 425         }
 426         return 0;
 427 }
 428
 429 static int match_next_pattern(struct grep_pat *p, char *bol, char *eol,
 430                               enum grep_context ctx,
 431                               regmatch_t *pmatch, int eflags)
 432 {
 433         regmatch_t match;
 434
 435         if (!match_one_pattern(p, bol, eol, ctx, &match, eflags))
 436                 return 0;
 437         if (match.rm_so < 0 || match.rm_eo < 0)
 438                 return 0;
 439         if (pmatch->rm_so >= 0 && pmatch->rm_eo >= 0) {
 440                 if (match.rm_so > pmatch->rm_so)
 441                         return 1;
 442                 if (match.rm_so == pmatch->rm_so && match.rm_eo < pmatch->rm_eo)
 443                         return 1;
 444         }
 445         pmatch->rm_so = match.rm_so;
 446         pmatch->rm_eo = match.rm_eo;
 447         return 1;
 448 }
 449
 450 static int next_match(struct grep_opt *opt, char *bol, char *eol,
 451                       enum grep_context ctx, regmatch_t *pmatch, int eflags)
 452 {
 453         struct grep_pat *p;
 454         int hit = 0;
 455
 456         pmatch->rm_so = pmatch->rm_eo = -1;
 457         if (bol < eol) {
 458                 for (p = opt->pattern_list; p; p = p->next) {
 459                         switch (p->token) {
 460                         case GREP_PATTERN: /* atom */
 461                         case GREP_PATTERN_HEAD:
 462                         case GREP_PATTERN_BODY:
 463                                 hit |= match_next_pattern(p, bol, eol, ctx,
 464                                                           pmatch, eflags);
 465                                 break;
 466                         default:
 467                                 break;
 468                         }
 469                 }
 470         }
 471         return hit;
 472 }
 473
 474 static void show_line(struct grep_opt *opt, char *bol, char *eol,
 475                       const char *name, unsigned lno, char sign)
 476 {
 477         int rest = eol - bol;
 478
 479         if (opt->null_following_name)
 480                 sign = '\0';
 481         if (opt->pathname)
 482                 printf("%s%c", name, sign);
 483         if (opt->linenum)
 484                 printf("%d%c", lno, sign);
 485         if (opt->color) {
 486                 regmatch_t match;
 487                 enum grep_context ctx = GREP_CONTEXT_BODY;
 488                 int ch = *eol;
 489                 int eflags = 0;
 490
 491                 *eol = '\0';
 492                 while (next_match(opt, bol, eol, ctx, &match, eflags)) {
 493                         printf("%.*s%s%.*s%s",
 494                                (int)match.rm_so, bol,
 495                                opt->color_match,
 496                                (int)(match.rm_eo - match.rm_so), bol + match.rm_so,
 497                                GIT_COLOR_RESET);
 498                         bol += match.rm_eo;
 499                         rest -= match.rm_eo;
 500                         eflags = REG_NOTBOL;
 501                 }
 502                 *eol = ch;
 503         }
 504         printf("%.*s\n", rest, bol);
 505 }
 506
 507 static int grep_buffer_1(struct grep_opt *opt, const char *name,
 508                          char *buf, unsigned long size, int collect_hits)
 509 {
 510         char *bol = buf;
 511         unsigned long left = size;
 512         unsigned lno = 1;
 513         struct pre_context_line {
 514                 char *bol;
 515                 char *eol;
 516         } *prev = NULL, *pcl;
 517         unsigned last_hit = 0;
 518         unsigned last_shown = 0;
 519         int binary_match_only = 0;
 520         const char *hunk_mark = "";
 521         unsigned count = 0;
 522         enum grep_context ctx = GREP_CONTEXT_HEAD;
 523
 524         if (buffer_is_binary(buf, size)) {
 525                 switch (opt->binary) {
 526                 case GREP_BINARY_DEFAULT:
 527                         binary_match_only = 1;
 528                         break;
 529                 case GREP_BINARY_NOMATCH:
 530                         return 0; /* Assume unmatch */
 531                         break;
 532                 default:
 533                         break;
 534                 }
 535         }
 536
 537         if (opt->pre_context)
 538                 prev = xcalloc(opt->pre_context, sizeof(*prev));
 539         if (opt->pre_context || opt->post_context)
 540                 hunk_mark = "--\n";
 541
 542         while (left) {
 543                 char *eol, ch;
 544                 int hit;
 545
 546                 eol = end_of_line(bol, &left);
 547                 ch = *eol;
 548                 *eol = 0;
 549
 550                 if ((ctx == GREP_CONTEXT_HEAD) && (eol == bol))
 551                         ctx = GREP_CONTEXT_BODY;
 552
 553                 hit = match_line(opt, bol, eol, ctx, collect_hits);
 554                 *eol = ch;
 555
 556                 if (collect_hits)
 557                         goto next_line;
 558
 559                 /* "grep -v -e foo -e bla" should list lines
 560                  * that do not have either, so inversion should
 561                  * be done outside.
 562                  */
 563                 if (opt->invert)
 564                         hit = !hit;
 565                 if (opt->unmatch_name_only) {
 566                         if (hit)
 567                                 return 0;
 568                         goto next_line;
 569                 }
 570                 if (hit) {
 571                         count++;
 572                         if (opt->status_only)
 573                                 return 1;
 574                         if (binary_match_only) {
 575                                 printf("Binary file %s matches\n", name);
 576                                 return 1;
 577                         }
 578                         if (opt->name_only) {
 579                                 show_name(opt, name);
 580                                 return 1;
 581                         }
 582                         /* Hit at this line.  If we haven't shown the
 583                          * pre-context lines, we would need to show them.
 584                          * When asked to do "count", this still show
 585                          * the context which is nonsense, but the user
 586                          * deserves to get that ;-).
 587                          */
 588                         if (opt->pre_context) {
 589                                 unsigned from;
 590                                 if (opt->pre_context < lno)
 591                                         from = lno - opt->pre_context;
 592                                 else
 593                                         from = 1;
 594                                 if (from <= last_shown)
 595                                         from = last_shown + 1;
 596                                 if (last_shown && from != last_shown + 1)
 597                                         fputs(hunk_mark, stdout);
 598                                 while (from < lno) {
 599                                         pcl = &prev[lno-from-1];
 600                                         show_line(opt, pcl->bol, pcl->eol,
 601                                                   name, from, '-');
 602                                         from++;
 603                                 }
 604                                 last_shown = lno-1;
 605                         }
 606                         if (last_shown && lno != last_shown + 1)
 607                                 fputs(hunk_mark, stdout);
 608                         if (!opt->count)
 609                                 show_line(opt, bol, eol, name, lno, ':');
 610                         last_shown = last_hit = lno;
 611                 }
 612                 else if (last_hit &&
 613                          lno <= last_hit + opt->post_context) {
 614                         /* If the last hit is within the post context,
 615                          * we need to show this line.
 616                          */
 617                         if (last_shown && lno != last_shown + 1)
 618                                 fputs(hunk_mark, stdout);
 619                         show_line(opt, bol, eol, name, lno, '-');
 620                         last_shown = lno;
 621                 }
 622                 if (opt->pre_context) {
 623                         memmove(prev+1, prev,
 624                                 (opt->pre_context-1) * sizeof(*prev));
 625                         prev->bol = bol;
 626                         prev->eol = eol;
 627                 }
 628
 629         next_line:
 630                 bol = eol + 1;
 631                 if (!left)
 632                         break;
 633                 left--;
 634                 lno++;
 635         }
 636
 637         free(prev);
 638         if (collect_hits)
 639                 return 0;
 640
 641         if (opt->status_only)
 642                 return 0;
 643         if (opt->unmatch_name_only) {
 644                 /* We did not see any hit, so we want to show this */
 645                 show_name(opt, name);
 646                 return 1;
 647         }
 648
 649         /* NEEDSWORK:
 650          * The real "grep -c foo *.c" gives many "bar.c:0" lines,
 651          * which feels mostly useless but sometimes useful.  Maybe
 652          * make it another option?  For now suppress them.
 653          */
 654         if (opt->count && count)
 655                 printf("%s%c%u\n", name,
 656                        opt->null_following_name ? '\0' : ':', count);
 657         return !!last_hit;
 658 }
 659
 660 static void clr_hit_marker(struct grep_expr *x)
 661 {
 662         /* All-hit markers are meaningful only at the very top level
 663          * OR node.
 664          */
 665         while (1) {
 666                 x->hit = 0;
 667                 if (x->node != GREP_NODE_OR)
 668                         return;
 669                 x->u.binary.left->hit = 0;
 670                 x = x->u.binary.right;
 671         }
 672 }
 673
 674 static int chk_hit_marker(struct grep_expr *x)
 675 {
 676         /* Top level nodes have hit markers.  See if they all are hits */
 677         while (1) {
 678                 if (x->node != GREP_NODE_OR)
 679                         return x->hit;
 680                 if (!x->u.binary.left->hit)
 681                         return 0;
 682                 x = x->u.binary.right;
 683         }
 684 }
 685
 686 int grep_buffer(struct grep_opt *opt, const char *name, char *buf, unsigned long size)
 687 {
 688         /*
 689          * we do not have to do the two-pass grep when we do not check
 690          * buffer-wide "all-match".
 691          */
 692         if (!opt->all_match)
 693                 return grep_buffer_1(opt, name, buf, size, 0);
 694
 695         /* Otherwise the toplevel "or" terms hit a bit differently.
 696          * We first clear hit markers from them.
 697          */
 698         clr_hit_marker(opt->pattern_expression);
 699         grep_buffer_1(opt, name, buf, size, 1);
 700
 701         if (!chk_hit_marker(opt->pattern_expression))
 702                 return 0;
 703
 704         return grep_buffer_1(opt, name, buf, size, 0);
 705 }