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