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         p->word_regexp = opt->word_regexp;
  43
  44         if (opt->fixed || is_fixed(p->pattern))
  45                 p->fixed = 1;
  46         if (opt->regflags & REG_ICASE)
  47                 p->fixed = 0;
  48         if (p->fixed)
  49                 return;
  50
  51         err = regcomp(&p->regexp, p->pattern, opt->regflags);
  52         if (err) {
  53                 char errbuf[1024];
  54                 char where[1024];
  55                 if (p->no)
  56                         sprintf(where, "In '%s' at %d, ",
  57                                 p->origin, p->no);
  58                 else if (p->origin)
  59                         sprintf(where, "%s, ", p->origin);
  60                 else
  61                         where[0] = 0;
  62                 regerror(err, &p->regexp, errbuf, 1024);
  63                 regfree(&p->regexp);
  64                 die("%s'%s': %s", where, p->pattern, errbuf);
  65         }
  66 }
  67
  68 static struct grep_expr *compile_pattern_or(struct grep_pat **);
  69 static struct grep_expr *compile_pattern_atom(struct grep_pat **list)
  70 {
  71         struct grep_pat *p;
  72         struct grep_expr *x;
  73
  74         p = *list;
  75         if (!p)
  76                 return NULL;
  77         switch (p->token) {
  78         case GREP_PATTERN: /* atom */
  79         case GREP_PATTERN_HEAD:
  80         case GREP_PATTERN_BODY:
  81                 x = xcalloc(1, sizeof (struct grep_expr));
  82                 x->node = GREP_NODE_ATOM;
  83                 x->u.atom = p;
  84                 *list = p->next;
  85                 return x;
  86         case GREP_OPEN_PAREN:
  87                 *list = p->next;
  88                 x = compile_pattern_or(list);
  89                 if (!*list || (*list)->token != GREP_CLOSE_PAREN)
  90                         die("unmatched parenthesis");
  91                 *list = (*list)->next;
  92                 return x;
  93         default:
  94                 return NULL;
  95         }
  96 }
  97
  98 static struct grep_expr *compile_pattern_not(struct grep_pat **list)
  99 {
 100         struct grep_pat *p;
 101         struct grep_expr *x;
 102
 103         p = *list;
 104         if (!p)
 105                 return NULL;
 106         switch (p->token) {
 107         case GREP_NOT:
 108                 if (!p->next)
 109                         die("--not not followed by pattern expression");
 110                 *list = p->next;
 111                 x = xcalloc(1, sizeof (struct grep_expr));
 112                 x->node = GREP_NODE_NOT;
 113                 x->u.unary = compile_pattern_not(list);
 114                 if (!x->u.unary)
 115                         die("--not followed by non pattern expression");
 116                 return x;
 117         default:
 118                 return compile_pattern_atom(list);
 119         }
 120 }
 121
 122 static struct grep_expr *compile_pattern_and(struct grep_pat **list)
 123 {
 124         struct grep_pat *p;
 125         struct grep_expr *x, *y, *z;
 126
 127         x = compile_pattern_not(list);
 128         p = *list;
 129         if (p && p->token == GREP_AND) {
 130                 if (!p->next)
 131                         die("--and not followed by pattern expression");
 132                 *list = p->next;
 133                 y = compile_pattern_and(list);
 134                 if (!y)
 135                         die("--and not followed by pattern expression");
 136                 z = xcalloc(1, sizeof (struct grep_expr));
 137                 z->node = GREP_NODE_AND;
 138                 z->u.binary.left = x;
 139                 z->u.binary.right = y;
 140                 return z;
 141         }
 142         return x;
 143 }
 144
 145 static struct grep_expr *compile_pattern_or(struct grep_pat **list)
 146 {
 147         struct grep_pat *p;
 148         struct grep_expr *x, *y, *z;
 149
 150         x = compile_pattern_and(list);
 151         p = *list;
 152         if (x && p && p->token != GREP_CLOSE_PAREN) {
 153                 y = compile_pattern_or(list);
 154                 if (!y)
 155                         die("not a pattern expression %s", p->pattern);
 156                 z = xcalloc(1, sizeof (struct grep_expr));
 157                 z->node = GREP_NODE_OR;
 158                 z->u.binary.left = x;
 159                 z->u.binary.right = y;
 160                 return z;
 161         }
 162         return x;
 163 }
 164
 165 static struct grep_expr *compile_pattern_expr(struct grep_pat **list)
 166 {
 167         return compile_pattern_or(list);
 168 }
 169
 170 void compile_grep_patterns(struct grep_opt *opt)
 171 {
 172         struct grep_pat *p;
 173
 174         if (opt->all_match)
 175                 opt->extended = 1;
 176
 177         for (p = opt->pattern_list; p; p = p->next) {
 178                 switch (p->token) {
 179                 case GREP_PATTERN: /* atom */
 180                 case GREP_PATTERN_HEAD:
 181                 case GREP_PATTERN_BODY:
 182                         compile_regexp(p, opt);
 183                         break;
 184                 default:
 185                         opt->extended = 1;
 186                         break;
 187                 }
 188         }
 189
 190         if (!opt->extended)
 191                 return;
 192
 193         /* Then bundle them up in an expression.
 194          * A classic recursive descent parser would do.
 195          */
 196         p = opt->pattern_list;
 197         if (p)
 198                 opt->pattern_expression = compile_pattern_expr(&p);
 199         if (p)
 200                 die("incomplete pattern expression: %s", p->pattern);
 201 }
 202
 203 static void free_pattern_expr(struct grep_expr *x)
 204 {
 205         switch (x->node) {
 206         case GREP_NODE_ATOM:
 207                 break;
 208         case GREP_NODE_NOT:
 209                 free_pattern_expr(x->u.unary);
 210                 break;
 211         case GREP_NODE_AND:
 212         case GREP_NODE_OR:
 213                 free_pattern_expr(x->u.binary.left);
 214                 free_pattern_expr(x->u.binary.right);
 215                 break;
 216         }
 217         free(x);
 218 }
 219
 220 void free_grep_patterns(struct grep_opt *opt)
 221 {
 222         struct grep_pat *p, *n;
 223
 224         for (p = opt->pattern_list; p; p = n) {
 225                 n = p->next;
 226                 switch (p->token) {
 227                 case GREP_PATTERN: /* atom */
 228                 case GREP_PATTERN_HEAD:
 229                 case GREP_PATTERN_BODY:
 230                         regfree(&p->regexp);
 231                         break;
 232                 default:
 233                         break;
 234                 }
 235                 free(p);
 236         }
 237
 238         if (!opt->extended)
 239                 return;
 240         free_pattern_expr(opt->pattern_expression);
 241 }
 242
 243 static char *end_of_line(char *cp, unsigned long *left)
 244 {
 245         unsigned long l = *left;
 246         while (l && *cp != '\n') {
 247                 l--;
 248                 cp++;
 249         }
 250         *left = l;
 251         return cp;
 252 }
 253
 254 static int word_char(char ch)
 255 {
 256         return isalnum(ch) || ch == '_';
 257 }
 258
 259 static void show_name(struct grep_opt *opt, const char *name)
 260 {
 261         printf("%s%c", name, opt->null_following_name ? '\0' : '\n');
 262 }
 263
 264 static int fixmatch(const char *pattern, char *line, regmatch_t *match)
 265 {
 266         char *hit = strstr(line, pattern);
 267         if (!hit) {
 268                 match->rm_so = match->rm_eo = -1;
 269                 return REG_NOMATCH;
 270         }
 271         else {
 272                 match->rm_so = hit - line;
 273                 match->rm_eo = match->rm_so + strlen(pattern);
 274                 return 0;
 275         }
 276 }
 277
 278 static int strip_timestamp(char *bol, char **eol_p)
 279 {
 280         char *eol = *eol_p;
 281         int ch;
 282
 283         while (bol < --eol) {
 284                 if (*eol != '>')
 285                         continue;
 286                 *eol_p = ++eol;
 287                 ch = *eol;
 288                 *eol = '\0';
 289                 return ch;
 290         }
 291         return 0;
 292 }
 293
 294 static struct {
 295         const char *field;
 296         size_t len;
 297 } header_field[] = {
 298         { "author ", 7 },
 299         { "committer ", 10 },
 300 };
 301
 302 static int match_one_pattern(struct grep_pat *p, char *bol, char *eol,
 303                              enum grep_context ctx,
 304                              regmatch_t *pmatch, int eflags)
 305 {
 306         int hit = 0;
 307         int saved_ch = 0;
 308         const char *start = bol;
 309
 310         if ((p->token != GREP_PATTERN) &&
 311             ((p->token == GREP_PATTERN_HEAD) != (ctx == GREP_CONTEXT_HEAD)))
 312                 return 0;
 313
 314         if (p->token == GREP_PATTERN_HEAD) {
 315                 const char *field;
 316                 size_t len;
 317                 assert(p->field < ARRAY_SIZE(header_field));
 318                 field = header_field[p->field].field;
 319                 len = header_field[p->field].len;
 320                 if (strncmp(bol, field, len))
 321                         return 0;
 322                 bol += len;
 323                 saved_ch = strip_timestamp(bol, &eol);
 324         }
 325
 326  again:
 327         if (p->fixed)
 328                 hit = !fixmatch(p->pattern, bol, pmatch);
 329         else
 330                 hit = !regexec(&p->regexp, bol, 1, pmatch, eflags);
 331
 332         if (hit && p->word_regexp) {
 333                 if ((pmatch[0].rm_so < 0) ||
 334                     (eol - bol) < pmatch[0].rm_so ||
 335                     (pmatch[0].rm_eo < 0) ||
 336                     (eol - bol) < pmatch[0].rm_eo)
 337                         die("regexp returned nonsense");
 338
 339                 /* Match beginning must be either beginning of the
 340                  * line, or at word boundary (i.e. the last char must
 341                  * not be a word char).  Similarly, match end must be
 342                  * either end of the line, or at word boundary
 343                  * (i.e. the next char must not be a word char).
 344                  */
 345                 if ( ((pmatch[0].rm_so == 0) ||
 346                       !word_char(bol[pmatch[0].rm_so-1])) &&
 347                      ((pmatch[0].rm_eo == (eol-bol)) ||
 348                       !word_char(bol[pmatch[0].rm_eo])) )
 349                         ;
 350                 else
 351                         hit = 0;
 352
 353                 /* Words consist of at least one character. */
 354                 if (pmatch->rm_so == pmatch->rm_eo)
 355                         hit = 0;
 356
 357                 if (!hit && pmatch[0].rm_so + bol + 1 < eol) {
 358                         /* There could be more than one match on the
 359                          * line, and the first match might not be
 360                          * strict word match.  But later ones could be!
 361                          * Forward to the next possible start, i.e. the
 362                          * next position following a non-word char.
 363                          */
 364                         bol = pmatch[0].rm_so + bol + 1;
 365                         while (word_char(bol[-1]) && bol < eol)
 366                                 bol++;
 367                         eflags |= REG_NOTBOL;
 368                         if (bol < eol)
 369                                 goto again;
 370                 }
 371         }
 372         if (p->token == GREP_PATTERN_HEAD && saved_ch)
 373                 *eol = saved_ch;
 374         if (hit) {
 375                 pmatch[0].rm_so += bol - start;
 376                 pmatch[0].rm_eo += bol - start;
 377         }
 378         return hit;
 379 }
 380
 381 static int match_expr_eval(struct grep_expr *x, char *bol, char *eol,
 382                            enum grep_context ctx, int collect_hits)
 383 {
 384         int h = 0;
 385         regmatch_t match;
 386
 387         if (!x)
 388                 die("Not a valid grep expression");
 389         switch (x->node) {
 390         case GREP_NODE_ATOM:
 391                 h = match_one_pattern(x->u.atom, bol, eol, ctx, &match, 0);
 392                 break;
 393         case GREP_NODE_NOT:
 394                 h = !match_expr_eval(x->u.unary, bol, eol, ctx, 0);
 395                 break;
 396         case GREP_NODE_AND:
 397                 if (!match_expr_eval(x->u.binary.left, bol, eol, ctx, 0))
 398                         return 0;
 399                 h = match_expr_eval(x->u.binary.right, bol, eol, ctx, 0);
 400                 break;
 401         case GREP_NODE_OR:
 402                 if (!collect_hits)
 403                         return (match_expr_eval(x->u.binary.left,
 404                                                 bol, eol, ctx, 0) ||
 405                                 match_expr_eval(x->u.binary.right,
 406                                                 bol, eol, ctx, 0));
 407                 h = match_expr_eval(x->u.binary.left, bol, eol, ctx, 0);
 408                 x->u.binary.left->hit |= h;
 409                 h |= match_expr_eval(x->u.binary.right, bol, eol, ctx, 1);
 410                 break;
 411         default:
 412                 die("Unexpected node type (internal error) %d", x->node);
 413         }
 414         if (collect_hits)
 415                 x->hit |= h;
 416         return h;
 417 }
 418
 419 static int match_expr(struct grep_opt *opt, char *bol, char *eol,
 420                       enum grep_context ctx, int collect_hits)
 421 {
 422         struct grep_expr *x = opt->pattern_expression;
 423         return match_expr_eval(x, bol, eol, ctx, collect_hits);
 424 }
 425
 426 static int match_line(struct grep_opt *opt, char *bol, char *eol,
 427                       enum grep_context ctx, int collect_hits)
 428 {
 429         struct grep_pat *p;
 430         regmatch_t match;
 431
 432         if (opt->extended)
 433                 return match_expr(opt, bol, eol, ctx, collect_hits);
 434
 435         /* we do not call with collect_hits without being extended */
 436         for (p = opt->pattern_list; p; p = p->next) {
 437                 if (match_one_pattern(p, bol, eol, ctx, &match, 0))
 438                         return 1;
 439         }
 440         return 0;
 441 }
 442
 443 static int match_next_pattern(struct grep_pat *p, char *bol, char *eol,
 444                               enum grep_context ctx,
 445                               regmatch_t *pmatch, int eflags)
 446 {
 447         regmatch_t match;
 448
 449         if (!match_one_pattern(p, bol, eol, ctx, &match, eflags))
 450                 return 0;
 451         if (match.rm_so < 0 || match.rm_eo < 0)
 452                 return 0;
 453         if (pmatch->rm_so >= 0 && pmatch->rm_eo >= 0) {
 454                 if (match.rm_so > pmatch->rm_so)
 455                         return 1;
 456                 if (match.rm_so == pmatch->rm_so && match.rm_eo < pmatch->rm_eo)
 457                         return 1;
 458         }
 459         pmatch->rm_so = match.rm_so;
 460         pmatch->rm_eo = match.rm_eo;
 461         return 1;
 462 }
 463
 464 static int next_match(struct grep_opt *opt, char *bol, char *eol,
 465                       enum grep_context ctx, regmatch_t *pmatch, int eflags)
 466 {
 467         struct grep_pat *p;
 468         int hit = 0;
 469
 470         pmatch->rm_so = pmatch->rm_eo = -1;
 471         if (bol < eol) {
 472                 for (p = opt->pattern_list; p; p = p->next) {
 473                         switch (p->token) {
 474                         case GREP_PATTERN: /* atom */
 475                         case GREP_PATTERN_HEAD:
 476                         case GREP_PATTERN_BODY:
 477                                 hit |= match_next_pattern(p, bol, eol, ctx,
 478                                                           pmatch, eflags);
 479                                 break;
 480                         default:
 481                                 break;
 482                         }
 483                 }
 484         }
 485         return hit;
 486 }
 487
 488 static void show_line(struct grep_opt *opt, char *bol, char *eol,
 489                       const char *name, unsigned lno, char sign)
 490 {
 491         int rest = eol - bol;
 492
 493         if (opt->null_following_name)
 494                 sign = '\0';
 495         if (opt->pathname)
 496                 printf("%s%c", name, sign);
 497         if (opt->linenum)
 498                 printf("%d%c", lno, sign);
 499         if (opt->color) {
 500                 regmatch_t match;
 501                 enum grep_context ctx = GREP_CONTEXT_BODY;
 502                 int ch = *eol;
 503                 int eflags = 0;
 504
 505                 *eol = '\0';
 506                 while (next_match(opt, bol, eol, ctx, &match, eflags)) {
 507                         if (match.rm_so == match.rm_eo)
 508                                 break;
 509                         printf("%.*s%s%.*s%s",
 510                                (int)match.rm_so, bol,
 511                                opt->color_match,
 512                                (int)(match.rm_eo - match.rm_so), bol + match.rm_so,
 513                                GIT_COLOR_RESET);
 514                         bol += match.rm_eo;
 515                         rest -= match.rm_eo;
 516                         eflags = REG_NOTBOL;
 517                 }
 518                 *eol = ch;
 519         }
 520         printf("%.*s\n", rest, bol);
 521 }
 522
 523 static int grep_buffer_1(struct grep_opt *opt, const char *name,
 524                          char *buf, unsigned long size, int collect_hits)
 525 {
 526         char *bol = buf;
 527         unsigned long left = size;
 528         unsigned lno = 1;
 529         struct pre_context_line {
 530                 char *bol;
 531                 char *eol;
 532         } *prev = NULL, *pcl;
 533         unsigned last_hit = 0;
 534         unsigned last_shown = 0;
 535         int binary_match_only = 0;
 536         const char *hunk_mark = "";
 537         unsigned count = 0;
 538         enum grep_context ctx = GREP_CONTEXT_HEAD;
 539
 540         if (buffer_is_binary(buf, size)) {
 541                 switch (opt->binary) {
 542                 case GREP_BINARY_DEFAULT:
 543                         binary_match_only = 1;
 544                         break;
 545                 case GREP_BINARY_NOMATCH:
 546                         return 0; /* Assume unmatch */
 547                         break;
 548                 default:
 549                         break;
 550                 }
 551         }
 552
 553         if (opt->pre_context)
 554                 prev = xcalloc(opt->pre_context, sizeof(*prev));
 555         if (opt->pre_context || opt->post_context)
 556                 hunk_mark = "--\n";
 557
 558         while (left) {
 559                 char *eol, ch;
 560                 int hit;
 561
 562                 eol = end_of_line(bol, &left);
 563                 ch = *eol;
 564                 *eol = 0;
 565
 566                 if ((ctx == GREP_CONTEXT_HEAD) && (eol == bol))
 567                         ctx = GREP_CONTEXT_BODY;
 568
 569                 hit = match_line(opt, bol, eol, ctx, collect_hits);
 570                 *eol = ch;
 571
 572                 if (collect_hits)
 573                         goto next_line;
 574
 575                 /* "grep -v -e foo -e bla" should list lines
 576                  * that do not have either, so inversion should
 577                  * be done outside.
 578                  */
 579                 if (opt->invert)
 580                         hit = !hit;
 581                 if (opt->unmatch_name_only) {
 582                         if (hit)
 583                                 return 0;
 584                         goto next_line;
 585                 }
 586                 if (hit) {
 587                         count++;
 588                         if (opt->status_only)
 589                                 return 1;
 590                         if (binary_match_only) {
 591                                 printf("Binary file %s matches\n", name);
 592                                 return 1;
 593                         }
 594                         if (opt->name_only) {
 595                                 show_name(opt, name);
 596                                 return 1;
 597                         }
 598                         /* Hit at this line.  If we haven't shown the
 599                          * pre-context lines, we would need to show them.
 600                          * When asked to do "count", this still show
 601                          * the context which is nonsense, but the user
 602                          * deserves to get that ;-).
 603                          */
 604                         if (opt->pre_context) {
 605                                 unsigned from;
 606                                 if (opt->pre_context < lno)
 607                                         from = lno - opt->pre_context;
 608                                 else
 609                                         from = 1;
 610                                 if (from <= last_shown)
 611                                         from = last_shown + 1;
 612                                 if (last_shown && from != last_shown + 1)
 613                                         fputs(hunk_mark, stdout);
 614                                 while (from < lno) {
 615                                         pcl = &prev[lno-from-1];
 616                                         show_line(opt, pcl->bol, pcl->eol,
 617                                                   name, from, '-');
 618                                         from++;
 619                                 }
 620                                 last_shown = lno-1;
 621                         }
 622                         if (last_shown && lno != last_shown + 1)
 623                                 fputs(hunk_mark, stdout);
 624                         if (!opt->count)
 625                                 show_line(opt, bol, eol, name, lno, ':');
 626                         last_shown = last_hit = lno;
 627                 }
 628                 else if (last_hit &&
 629                          lno <= last_hit + opt->post_context) {
 630                         /* If the last hit is within the post context,
 631                          * we need to show this line.
 632                          */
 633                         if (last_shown && lno != last_shown + 1)
 634                                 fputs(hunk_mark, stdout);
 635                         show_line(opt, bol, eol, name, lno, '-');
 636                         last_shown = lno;
 637                 }
 638                 if (opt->pre_context) {
 639                         memmove(prev+1, prev,
 640                                 (opt->pre_context-1) * sizeof(*prev));
 641                         prev->bol = bol;
 642                         prev->eol = eol;
 643                 }
 644
 645         next_line:
 646                 bol = eol + 1;
 647                 if (!left)
 648                         break;
 649                 left--;
 650                 lno++;
 651         }
 652
 653         free(prev);
 654         if (collect_hits)
 655                 return 0;
 656
 657         if (opt->status_only)
 658                 return 0;
 659         if (opt->unmatch_name_only) {
 660                 /* We did not see any hit, so we want to show this */
 661                 show_name(opt, name);
 662                 return 1;
 663         }
 664
 665         /* NEEDSWORK:
 666          * The real "grep -c foo *.c" gives many "bar.c:0" lines,
 667          * which feels mostly useless but sometimes useful.  Maybe
 668          * make it another option?  For now suppress them.
 669          */
 670         if (opt->count && count)
 671                 printf("%s%c%u\n", name,
 672                        opt->null_following_name ? '\0' : ':', count);
 673         return !!last_hit;
 674 }
 675
 676 static void clr_hit_marker(struct grep_expr *x)
 677 {
 678         /* All-hit markers are meaningful only at the very top level
 679          * OR node.
 680          */
 681         while (1) {
 682                 x->hit = 0;
 683                 if (x->node != GREP_NODE_OR)
 684                         return;
 685                 x->u.binary.left->hit = 0;
 686                 x = x->u.binary.right;
 687         }
 688 }
 689
 690 static int chk_hit_marker(struct grep_expr *x)
 691 {
 692         /* Top level nodes have hit markers.  See if they all are hits */
 693         while (1) {
 694                 if (x->node != GREP_NODE_OR)
 695                         return x->hit;
 696                 if (!x->u.binary.left->hit)
 697                         return 0;
 698                 x = x->u.binary.right;
 699         }
 700 }
 701
 702 int grep_buffer(struct grep_opt *opt, const char *name, char *buf, unsigned long size)
 703 {
 704         /*
 705          * we do not have to do the two-pass grep when we do not check
 706          * buffer-wide "all-match".
 707          */
 708         if (!opt->all_match)
 709                 return grep_buffer_1(opt, name, buf, size, 0);
 710
 711         /* Otherwise the toplevel "or" terms hit a bit differently.
 712          * We first clear hit markers from them.
 713          */
 714         clr_hit_marker(opt->pattern_expression);
 715         grep_buffer_1(opt, name, buf, size, 1);
 716
 717         if (!chk_hit_marker(opt->pattern_expression))
 718                 return 0;
 719
 720         return grep_buffer_1(opt, name, buf, size, 0);
 721 }