grep.c

   1 #include "cache.h"
   2 #include "grep.h"
   3
   4 void append_grep_pattern(struct grep_opt *opt, const char *pat,
   5                          const char *origin, int no, enum grep_pat_token t)
   6 {
   7         struct grep_pat *p = xcalloc(1, sizeof(*p));
   8         p->pattern = pat;
   9         p->origin = origin;
  10         p->no = no;
  11         p->token = t;
  12         *opt->pattern_tail = p;
  13         opt->pattern_tail = &p->next;
  14         p->next = NULL;
  15 }
  16
  17 static void compile_regexp(struct grep_pat *p, struct grep_opt *opt)
  18 {
  19         int err = regcomp(&p->regexp, p->pattern, opt->regflags);
  20         if (err) {
  21                 char errbuf[1024];
  22                 char where[1024];
  23                 if (p->no)
  24                         sprintf(where, "In '%s' at %d, ",
  25                                 p->origin, p->no);
  26                 else if (p->origin)
  27                         sprintf(where, "%s, ", p->origin);
  28                 else
  29                         where[0] = 0;
  30                 regerror(err, &p->regexp, errbuf, 1024);
  31                 regfree(&p->regexp);
  32                 die("%s'%s': %s", where, p->pattern, errbuf);
  33         }
  34 }
  35
  36 static struct grep_expr *compile_pattern_or(struct grep_pat **);
  37 static struct grep_expr *compile_pattern_atom(struct grep_pat **list)
  38 {
  39         struct grep_pat *p;
  40         struct grep_expr *x;
  41
  42         p = *list;
  43         switch (p->token) {
  44         case GREP_PATTERN: /* atom */
  45         case GREP_PATTERN_HEAD:
  46         case GREP_PATTERN_BODY:
  47                 x = xcalloc(1, sizeof (struct grep_expr));
  48                 x->node = GREP_NODE_ATOM;
  49                 x->u.atom = p;
  50                 *list = p->next;
  51                 return x;
  52         case GREP_OPEN_PAREN:
  53                 *list = p->next;
  54                 x = compile_pattern_or(list);
  55                 if (!x)
  56                         return NULL;
  57                 if (!*list || (*list)->token != GREP_CLOSE_PAREN)
  58                         die("unmatched parenthesis");
  59                 *list = (*list)->next;
  60                 return x;
  61         default:
  62                 return NULL;
  63         }
  64 }
  65
  66 static struct grep_expr *compile_pattern_not(struct grep_pat **list)
  67 {
  68         struct grep_pat *p;
  69         struct grep_expr *x;
  70
  71         p = *list;
  72         switch (p->token) {
  73         case GREP_NOT:
  74                 if (!p->next)
  75                         die("--not not followed by pattern expression");
  76                 *list = p->next;
  77                 x = xcalloc(1, sizeof (struct grep_expr));
  78                 x->node = GREP_NODE_NOT;
  79                 x->u.unary = compile_pattern_not(list);
  80                 if (!x->u.unary)
  81                         die("--not followed by non pattern expression");
  82                 return x;
  83         default:
  84                 return compile_pattern_atom(list);
  85         }
  86 }
  87
  88 static struct grep_expr *compile_pattern_and(struct grep_pat **list)
  89 {
  90         struct grep_pat *p;
  91         struct grep_expr *x, *y, *z;
  92
  93         x = compile_pattern_not(list);
  94         p = *list;
  95         if (p && p->token == GREP_AND) {
  96                 if (!p->next)
  97                         die("--and not followed by pattern expression");
  98                 *list = p->next;
  99                 y = compile_pattern_and(list);
 100                 if (!y)
 101                         die("--and not followed by pattern expression");
 102                 z = xcalloc(1, sizeof (struct grep_expr));
 103                 z->node = GREP_NODE_AND;
 104                 z->u.binary.left = x;
 105                 z->u.binary.right = y;
 106                 return z;
 107         }
 108         return x;
 109 }
 110
 111 static struct grep_expr *compile_pattern_or(struct grep_pat **list)
 112 {
 113         struct grep_pat *p;
 114         struct grep_expr *x, *y, *z;
 115
 116         x = compile_pattern_and(list);
 117         p = *list;
 118         if (x && p && p->token != GREP_CLOSE_PAREN) {
 119                 y = compile_pattern_or(list);
 120                 if (!y)
 121                         die("not a pattern expression %s", p->pattern);
 122                 z = xcalloc(1, sizeof (struct grep_expr));
 123                 z->node = GREP_NODE_OR;
 124                 z->u.binary.left = x;
 125                 z->u.binary.right = y;
 126                 return z;
 127         }
 128         return x;
 129 }
 130
 131 static struct grep_expr *compile_pattern_expr(struct grep_pat **list)
 132 {
 133         return compile_pattern_or(list);
 134 }
 135
 136 void compile_grep_patterns(struct grep_opt *opt)
 137 {
 138         struct grep_pat *p;
 139
 140         if (opt->all_match)
 141                 opt->extended = 1;
 142
 143         for (p = opt->pattern_list; p; p = p->next) {
 144                 switch (p->token) {
 145                 case GREP_PATTERN: /* atom */
 146                 case GREP_PATTERN_HEAD:
 147                 case GREP_PATTERN_BODY:
 148                         if (!opt->fixed)
 149                                 compile_regexp(p, opt);
 150                         break;
 151                 default:
 152                         opt->extended = 1;
 153                         break;
 154                 }
 155         }
 156
 157         if (!opt->extended)
 158                 return;
 159
 160         /* Then bundle them up in an expression.
 161          * A classic recursive descent parser would do.
 162          */
 163         p = opt->pattern_list;
 164         opt->pattern_expression = compile_pattern_expr(&p);
 165         if (p)
 166                 die("incomplete pattern expression: %s", p->pattern);
 167 }
 168
 169 static void free_pattern_expr(struct grep_expr *x)
 170 {
 171         switch (x->node) {
 172         case GREP_NODE_ATOM:
 173                 break;
 174         case GREP_NODE_NOT:
 175                 free_pattern_expr(x->u.unary);
 176                 break;
 177         case GREP_NODE_AND:
 178         case GREP_NODE_OR:
 179                 free_pattern_expr(x->u.binary.left);
 180                 free_pattern_expr(x->u.binary.right);
 181                 break;
 182         }
 183         free(x);
 184 }
 185
 186 void free_grep_patterns(struct grep_opt *opt)
 187 {
 188         struct grep_pat *p, *n;
 189
 190         for (p = opt->pattern_list; p; p = n) {
 191                 n = p->next;
 192                 switch (p->token) {
 193                 case GREP_PATTERN: /* atom */
 194                 case GREP_PATTERN_HEAD:
 195                 case GREP_PATTERN_BODY:
 196                         regfree(&p->regexp);
 197                         break;
 198                 default:
 199                         break;
 200                 }
 201                 free(p);
 202         }
 203
 204         if (!opt->extended)
 205                 return;
 206         free_pattern_expr(opt->pattern_expression);
 207 }
 208
 209 static char *end_of_line(char *cp, unsigned long *left)
 210 {
 211         unsigned long l = *left;
 212         while (l && *cp != '\n') {
 213                 l--;
 214                 cp++;
 215         }
 216         *left = l;
 217         return cp;
 218 }
 219
 220 static int word_char(char ch)
 221 {
 222         return isalnum(ch) || ch == '_';
 223 }
 224
 225 static void show_line(struct grep_opt *opt, const char *bol, const char *eol,
 226                       const char *name, unsigned lno, char sign)
 227 {
 228         if (opt->pathname)
 229                 printf("%s%c", name, sign);
 230         if (opt->linenum)
 231                 printf("%d%c", lno, sign);
 232         printf("%.*s\n", (int)(eol-bol), bol);
 233 }
 234
 235 /*
 236  * NEEDSWORK: share code with diff.c
 237  */
 238 #define FIRST_FEW_BYTES 8000
 239 static int buffer_is_binary(const char *ptr, unsigned long size)
 240 {
 241         if (FIRST_FEW_BYTES < size)
 242                 size = FIRST_FEW_BYTES;
 243         return !!memchr(ptr, 0, size);
 244 }
 245
 246 static int fixmatch(const char *pattern, char *line, regmatch_t *match)
 247 {
 248         char *hit = strstr(line, pattern);
 249         if (!hit) {
 250                 match->rm_so = match->rm_eo = -1;
 251                 return REG_NOMATCH;
 252         }
 253         else {
 254                 match->rm_so = hit - line;
 255                 match->rm_eo = match->rm_so + strlen(pattern);
 256                 return 0;
 257         }
 258 }
 259
 260 static int match_one_pattern(struct grep_opt *opt, struct grep_pat *p, char *bol, char *eol, enum grep_context ctx)
 261 {
 262         int hit = 0;
 263         int at_true_bol = 1;
 264         regmatch_t pmatch[10];
 265
 266         if ((p->token != GREP_PATTERN) &&
 267             ((p->token == GREP_PATTERN_HEAD) != (ctx == GREP_CONTEXT_HEAD)))
 268                 return 0;
 269
 270  again:
 271         if (!opt->fixed) {
 272                 regex_t *exp = &p->regexp;
 273                 hit = !regexec(exp, bol, ARRAY_SIZE(pmatch),
 274                                pmatch, 0);
 275         }
 276         else {
 277                 hit = !fixmatch(p->pattern, bol, pmatch);
 278         }
 279
 280         if (hit && opt->word_regexp) {
 281                 if ((pmatch[0].rm_so < 0) ||
 282                     (eol - bol) <= pmatch[0].rm_so ||
 283                     (pmatch[0].rm_eo < 0) ||
 284                     (eol - bol) < pmatch[0].rm_eo)
 285                         die("regexp returned nonsense");
 286
 287                 /* Match beginning must be either beginning of the
 288                  * line, or at word boundary (i.e. the last char must
 289                  * not be a word char).  Similarly, match end must be
 290                  * either end of the line, or at word boundary
 291                  * (i.e. the next char must not be a word char).
 292                  */
 293                 if ( ((pmatch[0].rm_so == 0 && at_true_bol) ||
 294                       !word_char(bol[pmatch[0].rm_so-1])) &&
 295                      ((pmatch[0].rm_eo == (eol-bol)) ||
 296                       !word_char(bol[pmatch[0].rm_eo])) )
 297                         ;
 298                 else
 299                         hit = 0;
 300
 301                 if (!hit && pmatch[0].rm_so + bol + 1 < eol) {
 302                         /* There could be more than one match on the
 303                          * line, and the first match might not be
 304                          * strict word match.  But later ones could be!
 305                          */
 306                         bol = pmatch[0].rm_so + bol + 1;
 307                         at_true_bol = 0;
 308                         goto again;
 309                 }
 310         }
 311         return hit;
 312 }
 313
 314 static int match_expr_eval(struct grep_opt *o,
 315                            struct grep_expr *x,
 316                            char *bol, char *eol,
 317                            enum grep_context ctx,
 318                            int collect_hits)
 319 {
 320         int h = 0;
 321
 322         switch (x->node) {
 323         case GREP_NODE_ATOM:
 324                 h = match_one_pattern(o, x->u.atom, bol, eol, ctx);
 325                 break;
 326         case GREP_NODE_NOT:
 327                 h = !match_expr_eval(o, x->u.unary, bol, eol, ctx, 0);
 328                 break;
 329         case GREP_NODE_AND:
 330                 if (!collect_hits)
 331                         return (match_expr_eval(o, x->u.binary.left,
 332                                                 bol, eol, ctx, 0) &&
 333                                 match_expr_eval(o, x->u.binary.right,
 334                                                 bol, eol, ctx, 0));
 335                 h = match_expr_eval(o, x->u.binary.left, bol, eol, ctx, 0);
 336                 h &= match_expr_eval(o, x->u.binary.right, bol, eol, ctx, 0);
 337                 break;
 338         case GREP_NODE_OR:
 339                 if (!collect_hits)
 340                         return (match_expr_eval(o, x->u.binary.left,
 341                                                 bol, eol, ctx, 0) ||
 342                                 match_expr_eval(o, x->u.binary.right,
 343                                                 bol, eol, ctx, 0));
 344                 h = match_expr_eval(o, x->u.binary.left, bol, eol, ctx, 0);
 345                 x->u.binary.left->hit |= h;
 346                 h |= match_expr_eval(o, x->u.binary.right, bol, eol, ctx, 1);
 347                 break;
 348         default:
 349                 die("Unexpected node type (internal error) %d\n", x->node);
 350         }
 351         if (collect_hits)
 352                 x->hit |= h;
 353         return h;
 354 }
 355
 356 static int match_expr(struct grep_opt *opt, char *bol, char *eol,
 357                       enum grep_context ctx, int collect_hits)
 358 {
 359         struct grep_expr *x = opt->pattern_expression;
 360         return match_expr_eval(opt, x, bol, eol, ctx, collect_hits);
 361 }
 362
 363 static int match_line(struct grep_opt *opt, char *bol, char *eol,
 364                       enum grep_context ctx, int collect_hits)
 365 {
 366         struct grep_pat *p;
 367         if (opt->extended)
 368                 return match_expr(opt, bol, eol, ctx, collect_hits);
 369
 370         /* we do not call with collect_hits without being extended */
 371         for (p = opt->pattern_list; p; p = p->next) {
 372                 if (match_one_pattern(opt, p, bol, eol, ctx))
 373                         return 1;
 374         }
 375         return 0;
 376 }
 377
 378 static int grep_buffer_1(struct grep_opt *opt, const char *name,
 379                          char *buf, unsigned long size, int collect_hits)
 380 {
 381         char *bol = buf;
 382         unsigned long left = size;
 383         unsigned lno = 1;
 384         struct pre_context_line {
 385                 char *bol;
 386                 char *eol;
 387         } *prev = NULL, *pcl;
 388         unsigned last_hit = 0;
 389         unsigned last_shown = 0;
 390         int binary_match_only = 0;
 391         const char *hunk_mark = "";
 392         unsigned count = 0;
 393         enum grep_context ctx = GREP_CONTEXT_HEAD;
 394
 395         if (buffer_is_binary(buf, size)) {
 396                 switch (opt->binary) {
 397                 case GREP_BINARY_DEFAULT:
 398                         binary_match_only = 1;
 399                         break;
 400                 case GREP_BINARY_NOMATCH:
 401                         return 0; /* Assume unmatch */
 402                         break;
 403                 default:
 404                         break;
 405                 }
 406         }
 407
 408         if (opt->pre_context)
 409                 prev = xcalloc(opt->pre_context, sizeof(*prev));
 410         if (opt->pre_context || opt->post_context)
 411                 hunk_mark = "--\n";
 412
 413         while (left) {
 414                 char *eol, ch;
 415                 int hit;
 416
 417                 eol = end_of_line(bol, &left);
 418                 ch = *eol;
 419                 *eol = 0;
 420
 421                 if ((ctx == GREP_CONTEXT_HEAD) && (eol == bol))
 422                         ctx = GREP_CONTEXT_BODY;
 423
 424                 hit = match_line(opt, bol, eol, ctx, collect_hits);
 425                 *eol = ch;
 426
 427                 if (collect_hits)
 428                         goto next_line;
 429
 430                 /* "grep -v -e foo -e bla" should list lines
 431                  * that do not have either, so inversion should
 432                  * be done outside.
 433                  */
 434                 if (opt->invert)
 435                         hit = !hit;
 436                 if (opt->unmatch_name_only) {
 437                         if (hit)
 438                                 return 0;
 439                         goto next_line;
 440                 }
 441                 if (hit) {
 442                         count++;
 443                         if (opt->status_only)
 444                                 return 1;
 445                         if (binary_match_only) {
 446                                 printf("Binary file %s matches\n", name);
 447                                 return 1;
 448                         }
 449                         if (opt->name_only) {
 450                                 printf("%s\n", name);
 451                                 return 1;
 452                         }
 453                         /* Hit at this line.  If we haven't shown the
 454                          * pre-context lines, we would need to show them.
 455                          * When asked to do "count", this still show
 456                          * the context which is nonsense, but the user
 457                          * deserves to get that ;-).
 458                          */
 459                         if (opt->pre_context) {
 460                                 unsigned from;
 461                                 if (opt->pre_context < lno)
 462                                         from = lno - opt->pre_context;
 463                                 else
 464                                         from = 1;
 465                                 if (from <= last_shown)
 466                                         from = last_shown + 1;
 467                                 if (last_shown && from != last_shown + 1)
 468                                         printf(hunk_mark);
 469                                 while (from < lno) {
 470                                         pcl = &prev[lno-from-1];
 471                                         show_line(opt, pcl->bol, pcl->eol,
 472                                                   name, from, '-');
 473                                         from++;
 474                                 }
 475                                 last_shown = lno-1;
 476                         }
 477                         if (last_shown && lno != last_shown + 1)
 478                                 printf(hunk_mark);
 479                         if (!opt->count)
 480                                 show_line(opt, bol, eol, name, lno, ':');
 481                         last_shown = last_hit = lno;
 482                 }
 483                 else if (last_hit &&
 484                          lno <= last_hit + opt->post_context) {
 485                         /* If the last hit is within the post context,
 486                          * we need to show this line.
 487                          */
 488                         if (last_shown && lno != last_shown + 1)
 489                                 printf(hunk_mark);
 490                         show_line(opt, bol, eol, name, lno, '-');
 491                         last_shown = lno;
 492                 }
 493                 if (opt->pre_context) {
 494                         memmove(prev+1, prev,
 495                                 (opt->pre_context-1) * sizeof(*prev));
 496                         prev->bol = bol;
 497                         prev->eol = eol;
 498                 }
 499
 500         next_line:
 501                 bol = eol + 1;
 502                 if (!left)
 503                         break;
 504                 left--;
 505                 lno++;
 506         }
 507
 508         free(prev);
 509         if (collect_hits)
 510                 return 0;
 511
 512         if (opt->status_only)
 513                 return 0;
 514         if (opt->unmatch_name_only) {
 515                 /* We did not see any hit, so we want to show this */
 516                 printf("%s\n", name);
 517                 return 1;
 518         }
 519
 520         /* NEEDSWORK:
 521          * The real "grep -c foo *.c" gives many "bar.c:0" lines,
 522          * which feels mostly useless but sometimes useful.  Maybe
 523          * make it another option?  For now suppress them.
 524          */
 525         if (opt->count && count)
 526                 printf("%s:%u\n", name, count);
 527         return !!last_hit;
 528 }
 529
 530 static void clr_hit_marker(struct grep_expr *x)
 531 {
 532         /* All-hit markers are meaningful only at the very top level
 533          * OR node.
 534          */
 535         while (1) {
 536                 x->hit = 0;
 537                 if (x->node != GREP_NODE_OR)
 538                         return;
 539                 x->u.binary.left->hit = 0;
 540                 x = x->u.binary.right;
 541         }
 542 }
 543
 544 static int chk_hit_marker(struct grep_expr *x)
 545 {
 546         /* Top level nodes have hit markers.  See if they all are hits */
 547         while (1) {
 548                 if (x->node != GREP_NODE_OR)
 549                         return x->hit;
 550                 if (!x->u.binary.left->hit)
 551                         return 0;
 552                 x = x->u.binary.right;
 553         }
 554 }
 555
 556 int grep_buffer(struct grep_opt *opt, const char *name, char *buf, unsigned long size)
 557 {
 558         /*
 559          * we do not have to do the two-pass grep when we do not check
 560          * buffer-wide "all-match".
 561          */
 562         if (!opt->all_match)
 563                 return grep_buffer_1(opt, name, buf, size, 0);
 564
 565         /* Otherwise the toplevel "or" terms hit a bit differently.
 566          * We first clear hit markers from them.
 567          */
 568         clr_hit_marker(opt->pattern_expression);
 569         grep_buffer_1(opt, name, buf, size, 1);
 570
 571         if (!chk_hit_marker(opt->pattern_expression))
 572                 return 0;
 573
 574         return grep_buffer_1(opt, name, buf, size, 0);
 575 }