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