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