grep.c

   1 #include "cache.h"
   2 #include <regex.h>
   3 #include "grep.h"
   4
   5 void append_grep_pattern(struct grep_opt *opt, const char *pat,
   6                          const char *origin, int no, enum grep_pat_token t)
   7 {
   8         struct grep_pat *p = xcalloc(1, sizeof(*p));
   9         p->pattern = pat;
  10         p->origin = origin;
  11         p->no = no;
  12         p->token = t;
  13         *opt->pattern_tail = p;
  14         opt->pattern_tail = &p->next;
  15         p->next = NULL;
  16 }
  17
  18 static void compile_regexp(struct grep_pat *p, struct grep_opt *opt)
  19 {
  20         int err = regcomp(&p->regexp, p->pattern, opt->regflags);
  21         if (err) {
  22                 char errbuf[1024];
  23                 char where[1024];
  24                 if (p->no)
  25                         sprintf(where, "In '%s' at %d, ",
  26                                 p->origin, p->no);
  27                 else if (p->origin)
  28                         sprintf(where, "%s, ", p->origin);
  29                 else
  30                         where[0] = 0;
  31                 regerror(err, &p->regexp, errbuf, 1024);
  32                 regfree(&p->regexp);
  33                 die("%s'%s': %s", where, p->pattern, errbuf);
  34         }
  35 }
  36
  37 static struct grep_expr *compile_pattern_or(struct grep_pat **);
  38 static struct grep_expr *compile_pattern_atom(struct grep_pat **list)
  39 {
  40         struct grep_pat *p;
  41         struct grep_expr *x;
  42
  43         p = *list;
  44         switch (p->token) {
  45         case GREP_PATTERN: /* atom */
  46         case GREP_PATTERN_HEAD:
  47         case GREP_PATTERN_BODY:
  48                 x = xcalloc(1, sizeof (struct grep_expr));
  49                 x->node = GREP_NODE_ATOM;
  50                 x->u.atom = p;
  51                 *list = p->next;
  52                 return x;
  53         case GREP_OPEN_PAREN:
  54                 *list = p->next;
  55                 x = compile_pattern_or(list);
  56                 if (!x)
  57                         return NULL;
  58                 if (!*list || (*list)->token != GREP_CLOSE_PAREN)
  59                         die("unmatched parenthesis");
  60                 *list = (*list)->next;
  61                 return x;
  62         default:
  63                 return NULL;
  64         }
  65 }
  66
  67 static struct grep_expr *compile_pattern_not(struct grep_pat **list)
  68 {
  69         struct grep_pat *p;
  70         struct grep_expr *x;
  71
  72         p = *list;
  73         switch (p->token) {
  74         case GREP_NOT:
  75                 if (!p->next)
  76                         die("--not not followed by pattern expression");
  77                 *list = p->next;
  78                 x = xcalloc(1, sizeof (struct grep_expr));
  79                 x->node = GREP_NODE_NOT;
  80                 x->u.unary = compile_pattern_not(list);
  81                 if (!x->u.unary)
  82                         die("--not followed by non pattern expression");
  83                 return x;
  84         default:
  85                 return compile_pattern_atom(list);
  86         }
  87 }
  88
  89 static struct grep_expr *compile_pattern_and(struct grep_pat **list)
  90 {
  91         struct grep_pat *p;
  92         struct grep_expr *x, *y, *z;
  93
  94         x = compile_pattern_not(list);
  95         p = *list;
  96         if (p && p->token == GREP_AND) {
  97                 if (!p->next)
  98                         die("--and not followed by pattern expression");
  99                 *list = p->next;
 100                 y = compile_pattern_and(list);
 101                 if (!y)
 102                         die("--and not followed by pattern expression");
 103                 z = xcalloc(1, sizeof (struct grep_expr));
 104                 z->node = GREP_NODE_AND;
 105                 z->u.binary.left = x;
 106                 z->u.binary.right = y;
 107                 return z;
 108         }
 109         return x;
 110 }
 111
 112 static struct grep_expr *compile_pattern_or(struct grep_pat **list)
 113 {
 114         struct grep_pat *p;
 115         struct grep_expr *x, *y, *z;
 116
 117         x = compile_pattern_and(list);
 118         p = *list;
 119         if (x && p && p->token != GREP_CLOSE_PAREN) {
 120                 y = compile_pattern_or(list);
 121                 if (!y)
 122                         die("not a pattern expression %s", p->pattern);
 123                 z = xcalloc(1, sizeof (struct grep_expr));
 124                 z->node = GREP_NODE_OR;
 125                 z->u.binary.left = x;
 126                 z->u.binary.right = y;
 127                 return z;
 128         }
 129         return x;
 130 }
 131
 132 static struct grep_expr *compile_pattern_expr(struct grep_pat **list)
 133 {
 134         return compile_pattern_or(list);
 135 }
 136
 137 void compile_grep_patterns(struct grep_opt *opt)
 138 {
 139         struct grep_pat *p;
 140
 141         if (opt->all_match)
 142                 opt->extended = 1;
 143
 144         for (p = opt->pattern_list; p; p = p->next) {
 145                 switch (p->token) {
 146                 case GREP_PATTERN: /* atom */
 147                 case GREP_PATTERN_HEAD:
 148                 case GREP_PATTERN_BODY:
 149                         if (!opt->fixed)
 150                                 compile_regexp(p, opt);
 151                         break;
 152                 default:
 153                         opt->extended = 1;
 154                         break;
 155                 }
 156         }
 157
 158         if (!opt->extended)
 159                 return;
 160
 161         /* Then bundle them up in an expression.
 162          * A classic recursive descent parser would do.
 163          */
 164         p = opt->pattern_list;
 165         opt->pattern_expression = compile_pattern_expr(&p);
 166         if (p)
 167                 die("incomplete pattern expression: %s", p->pattern);
 168 }
 169
 170 static void free_pattern_expr(struct grep_expr *x)
 171 {
 172         switch (x->node) {
 173         case GREP_NODE_ATOM:
 174                 break;
 175         case GREP_NODE_NOT:
 176                 free_pattern_expr(x->u.unary);
 177                 break;
 178         case GREP_NODE_AND:
 179         case GREP_NODE_OR:
 180                 free_pattern_expr(x->u.binary.left);
 181                 free_pattern_expr(x->u.binary.right);
 182                 break;
 183         }
 184         free(x);
 185 }
 186
 187 void free_grep_patterns(struct grep_opt *opt)
 188 {
 189         struct grep_pat *p, *n;
 190
 191         for (p = opt->pattern_list; p; p = n) {
 192                 n = p->next;
 193                 switch (p->token) {
 194                 case GREP_PATTERN: /* atom */
 195                 case GREP_PATTERN_HEAD:
 196                 case GREP_PATTERN_BODY:
 197                         regfree(&p->regexp);
 198                         break;
 199                 default:
 200                         break;
 201                 }
 202                 free(p);
 203         }
 204
 205         if (!opt->extended)
 206                 return;
 207         free_pattern_expr(opt->pattern_expression);
 208 }
 209
 210 static char *end_of_line(char *cp, unsigned long *left)
 211 {
 212         unsigned long l = *left;
 213         while (l && *cp != '\n') {
 214                 l--;
 215                 cp++;
 216         }
 217         *left = l;
 218         return cp;
 219 }
 220
 221 static int word_char(char ch)
 222 {
 223         return isalnum(ch) || ch == '_';
 224 }
 225
 226 static void show_line(struct grep_opt *opt, const char *bol, const char *eol,
 227                       const char *name, unsigned lno, char sign)
 228 {
 229         if (opt->pathname)
 230                 printf("%s%c", name, sign);
 231         if (opt->linenum)
 232                 printf("%d%c", lno, sign);
 233         printf("%.*s\n", (int)(eol-bol), bol);
 234 }
 235
 236 /*
 237  * NEEDSWORK: share code with diff.c
 238  */
 239 #define FIRST_FEW_BYTES 8000
 240 static int buffer_is_binary(const char *ptr, unsigned long size)
 241 {
 242         if (FIRST_FEW_BYTES < size)
 243                 size = FIRST_FEW_BYTES;
 244         return !!memchr(ptr, 0, size);
 245 }
 246
 247 static int fixmatch(const char *pattern, char *line, regmatch_t *match)
 248 {
 249         char *hit = strstr(line, pattern);
 250         if (!hit) {
 251                 match->rm_so = match->rm_eo = -1;
 252                 return REG_NOMATCH;
 253         }
 254         else {
 255                 match->rm_so = hit - line;
 256                 match->rm_eo = match->rm_so + strlen(pattern);
 257                 return 0;
 258         }
 259 }
 260
 261 static int match_one_pattern(struct grep_opt *opt, struct grep_pat *p, char *bol, char *eol, enum grep_context ctx)
 262 {
 263         int hit = 0;
 264         int at_true_bol = 1;
 265         regmatch_t pmatch[10];
 266
 267         if ((p->token != GREP_PATTERN) &&
 268             ((p->token == GREP_PATTERN_HEAD) != (ctx == GREP_CONTEXT_HEAD)))
 269                 return 0;
 270
 271  again:
 272         if (!opt->fixed) {
 273                 regex_t *exp = &p->regexp;
 274                 hit = !regexec(exp, bol, ARRAY_SIZE(pmatch),
 275                                pmatch, 0);
 276         }
 277         else {
 278                 hit = !fixmatch(p->pattern, bol, pmatch);
 279         }
 280
 281         if (hit && opt->word_regexp) {
 282                 if ((pmatch[0].rm_so < 0) ||
 283                     (eol - bol) <= pmatch[0].rm_so ||
 284                     (pmatch[0].rm_eo < 0) ||
 285                     (eol - bol) < pmatch[0].rm_eo)
 286                         die("regexp returned nonsense");
 287
 288                 /* Match beginning must be either beginning of the
 289                  * line, or at word boundary (i.e. the last char must
 290                  * not be a word char).  Similarly, match end must be
 291                  * either end of the line, or at word boundary
 292                  * (i.e. the next char must not be a word char).
 293                  */
 294                 if ( ((pmatch[0].rm_so == 0 && at_true_bol) ||
 295                       !word_char(bol[pmatch[0].rm_so-1])) &&
 296                      ((pmatch[0].rm_eo == (eol-bol)) ||
 297                       !word_char(bol[pmatch[0].rm_eo])) )
 298                         ;
 299                 else
 300                         hit = 0;
 301
 302                 if (!hit && pmatch[0].rm_so + bol + 1 < eol) {
 303                         /* There could be more than one match on the
 304                          * line, and the first match might not be
 305                          * strict word match.  But later ones could be!
 306                          */
 307                         bol = pmatch[0].rm_so + bol + 1;
 308                         at_true_bol = 0;
 309                         goto again;
 310                 }
 311         }
 312         return hit;
 313 }
 314
 315 static int match_expr_eval(struct grep_opt *o,
 316                            struct grep_expr *x,
 317                            char *bol, char *eol,
 318                            enum grep_context ctx,
 319                            int collect_hits)
 320 {
 321         int h = 0;
 322
 323         switch (x->node) {
 324         case GREP_NODE_ATOM:
 325                 h = match_one_pattern(o, x->u.atom, bol, eol, ctx);
 326                 break;
 327         case GREP_NODE_NOT:
 328                 h = !match_expr_eval(o, x->u.unary, bol, eol, ctx, 0);
 329                 break;
 330         case GREP_NODE_AND:
 331                 if (!collect_hits)
 332                         return (match_expr_eval(o, x->u.binary.left,
 333                                                 bol, eol, ctx, 0) &&
 334                                 match_expr_eval(o, x->u.binary.right,
 335                                                 bol, eol, ctx, 0));
 336                 h = match_expr_eval(o, x->u.binary.left, bol, eol, ctx, 0);
 337                 h &= match_expr_eval(o, x->u.binary.right, bol, eol, ctx, 0);
 338                 break;
 339         case GREP_NODE_OR:
 340                 if (!collect_hits)
 341                         return (match_expr_eval(o, x->u.binary.left,
 342                                                 bol, eol, ctx, 0) ||
 343                                 match_expr_eval(o, x->u.binary.right,
 344                                                 bol, eol, ctx, 0));
 345                 h = match_expr_eval(o, x->u.binary.left, bol, eol, ctx, 0);
 346                 x->u.binary.left->hit |= h;
 347                 h |= match_expr_eval(o, x->u.binary.right, bol, eol, ctx, 1);
 348                 break;
 349         default:
 350                 die("Unexpected node type (internal error) %d\n", x->node);
 351         }
 352         if (collect_hits)
 353                 x->hit |= h;
 354         return h;
 355 }
 356
 357 static int match_expr(struct grep_opt *opt, char *bol, char *eol,
 358                       enum grep_context ctx, int collect_hits)
 359 {
 360         struct grep_expr *x = opt->pattern_expression;
 361         return match_expr_eval(opt, x, bol, eol, ctx, collect_hits);
 362 }
 363
 364 static int match_line(struct grep_opt *opt, char *bol, char *eol,
 365                       enum grep_context ctx, int collect_hits)
 366 {
 367         struct grep_pat *p;
 368         if (opt->extended)
 369                 return match_expr(opt, bol, eol, ctx, collect_hits);
 370
 371         /* we do not call with collect_hits without being extended */
 372         for (p = opt->pattern_list; p; p = p->next) {
 373                 if (match_one_pattern(opt, p, bol, eol, ctx))
 374                         return 1;
 375         }
 376         return 0;
 377 }
 378
 379 static int grep_buffer_1(struct grep_opt *opt, const char *name,
 380                          char *buf, unsigned long size, int collect_hits)
 381 {
 382         char *bol = buf;
 383         unsigned long left = size;
 384         unsigned lno = 1;
 385         struct pre_context_line {
 386                 char *bol;
 387                 char *eol;
 388         } *prev = NULL, *pcl;
 389         unsigned last_hit = 0;
 390         unsigned last_shown = 0;
 391         int binary_match_only = 0;
 392         const char *hunk_mark = "";
 393         unsigned count = 0;
 394         enum grep_context ctx = GREP_CONTEXT_HEAD;
 395
 396         if (buffer_is_binary(buf, size)) {
 397                 switch (opt->binary) {
 398                 case GREP_BINARY_DEFAULT:
 399                         binary_match_only = 1;
 400                         break;
 401                 case GREP_BINARY_NOMATCH:
 402                         return 0; /* Assume unmatch */
 403                         break;
 404                 default:
 405                         break;
 406                 }
 407         }
 408
 409         if (opt->pre_context)
 410                 prev = xcalloc(opt->pre_context, sizeof(*prev));
 411         if (opt->pre_context || opt->post_context)
 412                 hunk_mark = "--\n";
 413
 414         while (left) {
 415                 char *eol, ch;
 416                 int hit;
 417
 418                 eol = end_of_line(bol, &left);
 419                 ch = *eol;
 420                 *eol = 0;
 421
 422                 if ((ctx == GREP_CONTEXT_HEAD) && (eol == bol))
 423                         ctx = GREP_CONTEXT_BODY;
 424
 425                 hit = match_line(opt, bol, eol, ctx, collect_hits);
 426                 *eol = ch;
 427
 428                 if (collect_hits)
 429                         goto next_line;
 430
 431                 /* "grep -v -e foo -e bla" should list lines
 432                  * that do not have either, so inversion should
 433                  * be done outside.
 434                  */
 435                 if (opt->invert)
 436                         hit = !hit;
 437                 if (opt->unmatch_name_only) {
 438                         if (hit)
 439                                 return 0;
 440                         goto next_line;
 441                 }
 442                 if (hit) {
 443                         count++;
 444                         if (opt->status_only)
 445                                 return 1;
 446                         if (binary_match_only) {
 447                                 printf("Binary file %s matches\n", name);
 448                                 return 1;
 449                         }
 450                         if (opt->name_only) {
 451                                 printf("%s\n", name);
 452                                 return 1;
 453                         }
 454                         /* Hit at this line.  If we haven't shown the
 455                          * pre-context lines, we would need to show them.
 456                          * When asked to do "count", this still show
 457                          * the context which is nonsense, but the user
 458                          * deserves to get that ;-).
 459                          */
 460                         if (opt->pre_context) {
 461                                 unsigned from;
 462                                 if (opt->pre_context < lno)
 463                                         from = lno - opt->pre_context;
 464                                 else
 465                                         from = 1;
 466                                 if (from <= last_shown)
 467                                         from = last_shown + 1;
 468                                 if (last_shown && from != last_shown + 1)
 469                                         printf(hunk_mark);
 470                                 while (from < lno) {
 471                                         pcl = &prev[lno-from-1];
 472                                         show_line(opt, pcl->bol, pcl->eol,
 473                                                   name, from, '-');
 474                                         from++;
 475                                 }
 476                                 last_shown = lno-1;
 477                         }
 478                         if (last_shown && lno != last_shown + 1)
 479                                 printf(hunk_mark);
 480                         if (!opt->count)
 481                                 show_line(opt, bol, eol, name, lno, ':');
 482                         last_shown = last_hit = lno;
 483                 }
 484                 else if (last_hit &&
 485                          lno <= last_hit + opt->post_context) {
 486                         /* If the last hit is within the post context,
 487                          * we need to show this line.
 488                          */
 489                         if (last_shown && lno != last_shown + 1)
 490                                 printf(hunk_mark);
 491                         show_line(opt, bol, eol, name, lno, '-');
 492                         last_shown = lno;
 493                 }
 494                 if (opt->pre_context) {
 495                         memmove(prev+1, prev,
 496                                 (opt->pre_context-1) * sizeof(*prev));
 497                         prev->bol = bol;
 498                         prev->eol = eol;
 499                 }
 500
 501         next_line:
 502                 bol = eol + 1;
 503                 if (!left)
 504                         break;
 505                 left--;
 506                 lno++;
 507         }
 508
 509         free(prev);
 510         if (collect_hits)
 511                 return 0;
 512
 513         if (opt->status_only)
 514                 return 0;
 515         if (opt->unmatch_name_only) {
 516                 /* We did not see any hit, so we want to show this */
 517                 printf("%s\n", name);
 518                 return 1;
 519         }
 520
 521         /* NEEDSWORK:
 522          * The real "grep -c foo *.c" gives many "bar.c:0" lines,
 523          * which feels mostly useless but sometimes useful.  Maybe
 524          * make it another option?  For now suppress them.
 525          */
 526         if (opt->count && count)
 527                 printf("%s:%u\n", name, count);
 528         return !!last_hit;
 529 }
 530
 531 static void clr_hit_marker(struct grep_expr *x)
 532 {
 533         /* All-hit markers are meaningful only at the very top level
 534          * OR node.
 535          */
 536         while (1) {
 537                 x->hit = 0;
 538                 if (x->node != GREP_NODE_OR)
 539                         return;
 540                 x->u.binary.left->hit = 0;
 541                 x = x->u.binary.right;
 542         }
 543 }
 544
 545 static int chk_hit_marker(struct grep_expr *x)
 546 {
 547         /* Top level nodes have hit markers.  See if they all are hits */
 548         while (1) {
 549                 if (x->node != GREP_NODE_OR)
 550                         return x->hit;
 551                 if (!x->u.binary.left->hit)
 552                         return 0;
 553                 x = x->u.binary.right;
 554         }
 555 }
 556
 557 int grep_buffer(struct grep_opt *opt, const char *name, char *buf, unsigned long size)
 558 {
 559         /*
 560          * we do not have to do the two-pass grep when we do not check
 561          * buffer-wide "all-match".
 562          */
 563         if (!opt->all_match)
 564                 return grep_buffer_1(opt, name, buf, size, 0);
 565
 566         /* Otherwise the toplevel "or" terms hit a bit differently.
 567          * We first clear hit markers from them.
 568          */
 569         clr_hit_marker(opt->pattern_expression);
 570         grep_buffer_1(opt, name, buf, size, 1);
 571
 572         if (!chk_hit_marker(opt->pattern_expression))
 573                 return 0;
 574
 575         return grep_buffer_1(opt, name, buf, size, 0);
 576 }