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