grep.c

   1 #include "cache.h"
   2 #include <regex.h>
   3 #include "grep.h"
   4
   5 void append_grep_pattern(struct grep_opt *opt, const char *pat,
   6                          const char *origin, int no, enum grep_pat_token t)
   7 {
   8         struct grep_pat *p = xcalloc(1, sizeof(*p));
   9         p->pattern = pat;
  10         p->origin = origin;
  11         p->no = no;
  12         p->token = t;
  13         *opt->pattern_tail = p;
  14         opt->pattern_tail = &p->next;
  15         p->next = NULL;
  16 }
  17
  18 static void compile_regexp(struct grep_pat *p, struct grep_opt *opt)
  19 {
  20         int err = regcomp(&p->regexp, p->pattern, opt->regflags);
  21         if (err) {
  22                 char errbuf[1024];
  23                 char where[1024];
  24                 if (p->no)
  25                         sprintf(where, "In '%s' at %d, ",
  26                                 p->origin, p->no);
  27                 else if (p->origin)
  28                         sprintf(where, "%s, ", p->origin);
  29                 else
  30                         where[0] = 0;
  31                 regerror(err, &p->regexp, errbuf, 1024);
  32                 regfree(&p->regexp);
  33                 die("%s'%s': %s", where, p->pattern, errbuf);
  34         }
  35 }
  36
  37 static struct grep_expr *compile_pattern_expr(struct grep_pat **);
  38 static struct grep_expr *compile_pattern_atom(struct grep_pat **list)
  39 {
  40         struct grep_pat *p;
  41         struct grep_expr *x;
  42
  43         p = *list;
  44         switch (p->token) {
  45         case GREP_PATTERN: /* atom */
  46         case GREP_PATTERN_HEAD:
  47         case GREP_PATTERN_BODY:
  48                 x = xcalloc(1, sizeof (struct grep_expr));
  49                 x->node = GREP_NODE_ATOM;
  50                 x->u.atom = p;
  51                 *list = p->next;
  52                 return x;
  53         case GREP_OPEN_PAREN:
  54                 *list = p->next;
  55                 x = compile_pattern_expr(list);
  56                 if (!x)
  57                         return NULL;
  58                 if (!*list || (*list)->token != GREP_CLOSE_PAREN)
  59                         die("unmatched parenthesis");
  60                 *list = (*list)->next;
  61                 return x;
  62         default:
  63                 return NULL;
  64         }
  65 }
  66
  67 static struct grep_expr *compile_pattern_not(struct grep_pat **list)
  68 {
  69         struct grep_pat *p;
  70         struct grep_expr *x;
  71
  72         p = *list;
  73         switch (p->token) {
  74         case GREP_NOT:
  75                 if (!p->next)
  76                         die("--not not followed by pattern expression");
  77                 *list = p->next;
  78                 x = xcalloc(1, sizeof (struct grep_expr));
  79                 x->node = GREP_NODE_NOT;
  80                 x->u.unary = compile_pattern_not(list);
  81                 if (!x->u.unary)
  82                         die("--not followed by non pattern expression");
  83                 return x;
  84         default:
  85                 return compile_pattern_atom(list);
  86         }
  87 }
  88
  89 static struct grep_expr *compile_pattern_and(struct grep_pat **list)
  90 {
  91         struct grep_pat *p;
  92         struct grep_expr *x, *y, *z;
  93
  94         x = compile_pattern_not(list);
  95         p = *list;
  96         if (p && p->token == GREP_AND) {
  97                 if (!p->next)
  98                         die("--and not followed by pattern expression");
  99                 *list = p->next;
 100                 y = compile_pattern_and(list);
 101                 if (!y)
 102                         die("--and not followed by pattern expression");
 103                 z = xcalloc(1, sizeof (struct grep_expr));
 104                 z->node = GREP_NODE_AND;
 105                 z->u.binary.left = x;
 106                 z->u.binary.right = y;
 107                 return z;
 108         }
 109         return x;
 110 }
 111
 112 static struct grep_expr *compile_pattern_or(struct grep_pat **list)
 113 {
 114         struct grep_pat *p;
 115         struct grep_expr *x, *y, *z;
 116
 117         x = compile_pattern_and(list);
 118         p = *list;
 119         if (x && p && p->token != GREP_CLOSE_PAREN) {
 120                 y = compile_pattern_or(list);
 121                 if (!y)
 122                         die("not a pattern expression %s", p->pattern);
 123                 z = xcalloc(1, sizeof (struct grep_expr));
 124                 z->node = GREP_NODE_OR;
 125                 z->u.binary.left = x;
 126                 z->u.binary.right = y;
 127                 return z;
 128         }
 129         return x;
 130 }
 131
 132 static struct grep_expr *compile_pattern_expr(struct grep_pat **list)
 133 {
 134         return compile_pattern_or(list);
 135 }
 136
 137 void compile_grep_patterns(struct grep_opt *opt)
 138 {
 139         struct grep_pat *p;
 140
 141         for (p = opt->pattern_list; p; p = p->next) {
 142                 switch (p->token) {
 143                 case GREP_PATTERN: /* atom */
 144                 case GREP_PATTERN_HEAD:
 145                 case GREP_PATTERN_BODY:
 146                         if (!opt->fixed)
 147                                 compile_regexp(p, opt);
 148                         break;
 149                 default:
 150                         opt->extended = 1;
 151                         break;
 152                 }
 153         }
 154
 155         if (!opt->extended)
 156                 return;
 157
 158         /* Then bundle them up in an expression.
 159          * A classic recursive descent parser would do.
 160          */
 161         p = opt->pattern_list;
 162         opt->pattern_expression = compile_pattern_expr(&p);
 163         if (p)
 164                 die("incomplete pattern expression: %s", p->pattern);
 165 }
 166
 167 static void free_pattern_expr(struct grep_expr *x)
 168 {
 169         switch (x->node) {
 170         case GREP_NODE_ATOM:
 171                 break;
 172         case GREP_NODE_NOT:
 173                 free_pattern_expr(x->u.unary);
 174                 break;
 175         case GREP_NODE_AND:
 176         case GREP_NODE_OR:
 177                 free_pattern_expr(x->u.binary.left);
 178                 free_pattern_expr(x->u.binary.right);
 179                 break;
 180         }
 181         free(x);
 182 }
 183
 184 void free_grep_patterns(struct grep_opt *opt)
 185 {
 186         struct grep_pat *p, *n;
 187
 188         for (p = opt->pattern_list; p; p = n) {
 189                 n = p->next;
 190                 switch (p->token) {
 191                 case GREP_PATTERN: /* atom */
 192                 case GREP_PATTERN_HEAD:
 193                 case GREP_PATTERN_BODY:
 194                         regfree(&p->regexp);
 195                         break;
 196                 default:
 197                         break;
 198                 }
 199                 free(p);
 200         }
 201
 202         if (!opt->extended)
 203                 return;
 204         free_pattern_expr(opt->pattern_expression);
 205 }
 206
 207 static char *end_of_line(char *cp, unsigned long *left)
 208 {
 209         unsigned long l = *left;
 210         while (l && *cp != '\n') {
 211                 l--;
 212                 cp++;
 213         }
 214         *left = l;
 215         return cp;
 216 }
 217
 218 static int word_char(char ch)
 219 {
 220         return isalnum(ch) || ch == '_';
 221 }
 222
 223 static void show_line(struct grep_opt *opt, const char *bol, const char *eol,
 224                       const char *name, unsigned lno, char sign)
 225 {
 226         if (opt->pathname)
 227                 printf("%s%c", name, sign);
 228         if (opt->linenum)
 229                 printf("%d%c", lno, sign);
 230         printf("%.*s\n", (int)(eol-bol), bol);
 231 }
 232
 233 /*
 234  * NEEDSWORK: share code with diff.c
 235  */
 236 #define FIRST_FEW_BYTES 8000
 237 static int buffer_is_binary(const char *ptr, unsigned long size)
 238 {
 239         if (FIRST_FEW_BYTES < size)
 240                 size = FIRST_FEW_BYTES;
 241         return !!memchr(ptr, 0, size);
 242 }
 243
 244 static int fixmatch(const char *pattern, char *line, regmatch_t *match)
 245 {
 246         char *hit = strstr(line, pattern);
 247         if (!hit) {
 248                 match->rm_so = match->rm_eo = -1;
 249                 return REG_NOMATCH;
 250         }
 251         else {
 252                 match->rm_so = hit - line;
 253                 match->rm_eo = match->rm_so + strlen(pattern);
 254                 return 0;
 255         }
 256 }
 257
 258 static int match_one_pattern(struct grep_opt *opt, struct grep_pat *p, char *bol, char *eol, enum grep_context ctx)
 259 {
 260         int hit = 0;
 261         int at_true_bol = 1;
 262         regmatch_t pmatch[10];
 263
 264         if ((p->token != GREP_PATTERN) &&
 265             ((p->token == GREP_PATTERN_HEAD) != (ctx == GREP_CONTEXT_HEAD)))
 266                 return 0;
 267
 268  again:
 269         if (!opt->fixed) {
 270                 regex_t *exp = &p->regexp;
 271                 hit = !regexec(exp, bol, ARRAY_SIZE(pmatch),
 272                                pmatch, 0);
 273         }
 274         else {
 275                 hit = !fixmatch(p->pattern, bol, pmatch);
 276         }
 277
 278         if (hit && opt->word_regexp) {
 279                 if ((pmatch[0].rm_so < 0) ||
 280                     (eol - bol) <= pmatch[0].rm_so ||
 281                     (pmatch[0].rm_eo < 0) ||
 282                     (eol - bol) < pmatch[0].rm_eo)
 283                         die("regexp returned nonsense");
 284
 285                 /* Match beginning must be either beginning of the
 286                  * line, or at word boundary (i.e. the last char must
 287                  * not be a word char).  Similarly, match end must be
 288                  * either end of the line, or at word boundary
 289                  * (i.e. the next char must not be a word char).
 290                  */
 291                 if ( ((pmatch[0].rm_so == 0 && at_true_bol) ||
 292                       !word_char(bol[pmatch[0].rm_so-1])) &&
 293                      ((pmatch[0].rm_eo == (eol-bol)) ||
 294                       !word_char(bol[pmatch[0].rm_eo])) )
 295                         ;
 296                 else
 297                         hit = 0;
 298
 299                 if (!hit && pmatch[0].rm_so + bol + 1 < eol) {
 300                         /* There could be more than one match on the
 301                          * line, and the first match might not be
 302                          * strict word match.  But later ones could be!
 303                          */
 304                         bol = pmatch[0].rm_so + bol + 1;
 305                         at_true_bol = 0;
 306                         goto again;
 307                 }
 308         }
 309         return hit;
 310 }
 311
 312 static int match_expr_eval(struct grep_opt *opt,
 313                            struct grep_expr *x,
 314                            char *bol, char *eol,
 315                            enum grep_context ctx)
 316 {
 317         switch (x->node) {
 318         case GREP_NODE_ATOM:
 319                 return match_one_pattern(opt, x->u.atom, bol, eol, ctx);
 320                 break;
 321         case GREP_NODE_NOT:
 322                 return !match_expr_eval(opt, x->u.unary, bol, eol, ctx);
 323         case GREP_NODE_AND:
 324                 return (match_expr_eval(opt, x->u.binary.left, bol, eol, ctx) &&
 325                         match_expr_eval(opt, x->u.binary.right, bol, eol, ctx));
 326         case GREP_NODE_OR:
 327                 return (match_expr_eval(opt, x->u.binary.left, bol, eol, ctx) ||
 328                         match_expr_eval(opt, x->u.binary.right, bol, eol, ctx));
 329         }
 330         die("Unexpected node type (internal error) %d\n", x->node);
 331 }
 332
 333 static int match_expr(struct grep_opt *opt, char *bol, char *eol,
 334                       enum grep_context ctx)
 335 {
 336         struct grep_expr *x = opt->pattern_expression;
 337         return match_expr_eval(opt, x, bol, eol, ctx);
 338 }
 339
 340 static int match_line(struct grep_opt *opt, char *bol, char *eol,
 341                       enum grep_context ctx)
 342 {
 343         struct grep_pat *p;
 344         if (opt->extended)
 345                 return match_expr(opt, bol, eol, ctx);
 346         for (p = opt->pattern_list; p; p = p->next) {
 347                 if (match_one_pattern(opt, p, bol, eol, ctx))
 348                         return 1;
 349         }
 350         return 0;
 351 }
 352
 353 int grep_buffer(struct grep_opt *opt, const char *name, char *buf, unsigned long size)
 354 {
 355         char *bol = buf;
 356         unsigned long left = size;
 357         unsigned lno = 1;
 358         struct pre_context_line {
 359                 char *bol;
 360                 char *eol;
 361         } *prev = NULL, *pcl;
 362         unsigned last_hit = 0;
 363         unsigned last_shown = 0;
 364         int binary_match_only = 0;
 365         const char *hunk_mark = "";
 366         unsigned count = 0;
 367         enum grep_context ctx = GREP_CONTEXT_HEAD;
 368
 369         if (buffer_is_binary(buf, size)) {
 370                 switch (opt->binary) {
 371                 case GREP_BINARY_DEFAULT:
 372                         binary_match_only = 1;
 373                         break;
 374                 case GREP_BINARY_NOMATCH:
 375                         return 0; /* Assume unmatch */
 376                         break;
 377                 default:
 378                         break;
 379                 }
 380         }
 381
 382         if (opt->pre_context)
 383                 prev = xcalloc(opt->pre_context, sizeof(*prev));
 384         if (opt->pre_context || opt->post_context)
 385                 hunk_mark = "--\n";
 386
 387         while (left) {
 388                 char *eol, ch;
 389                 int hit = 0;
 390
 391                 eol = end_of_line(bol, &left);
 392                 ch = *eol;
 393                 *eol = 0;
 394
 395                 if ((ctx == GREP_CONTEXT_HEAD) && (eol == bol))
 396                         ctx = GREP_CONTEXT_BODY;
 397
 398                 hit = match_line(opt, bol, eol, ctx);
 399                 *eol = ch;
 400
 401                 /* "grep -v -e foo -e bla" should list lines
 402                  * that do not have either, so inversion should
 403                  * be done outside.
 404                  */
 405                 if (opt->invert)
 406                         hit = !hit;
 407                 if (opt->unmatch_name_only) {
 408                         if (hit)
 409                                 return 0;
 410                         goto next_line;
 411                 }
 412                 if (hit) {
 413                         count++;
 414                         if (opt->status_only)
 415                                 return 1;
 416                         if (binary_match_only) {
 417                                 printf("Binary file %s matches\n", name);
 418                                 return 1;
 419                         }
 420                         if (opt->name_only) {
 421                                 printf("%s\n", name);
 422                                 return 1;
 423                         }
 424                         /* Hit at this line.  If we haven't shown the
 425                          * pre-context lines, we would need to show them.
 426                          * When asked to do "count", this still show
 427                          * the context which is nonsense, but the user
 428                          * deserves to get that ;-).
 429                          */
 430                         if (opt->pre_context) {
 431                                 unsigned from;
 432                                 if (opt->pre_context < lno)
 433                                         from = lno - opt->pre_context;
 434                                 else
 435                                         from = 1;
 436                                 if (from <= last_shown)
 437                                         from = last_shown + 1;
 438                                 if (last_shown && from != last_shown + 1)
 439                                         printf(hunk_mark);
 440                                 while (from < lno) {
 441                                         pcl = &prev[lno-from-1];
 442                                         show_line(opt, pcl->bol, pcl->eol,
 443                                                   name, from, '-');
 444                                         from++;
 445                                 }
 446                                 last_shown = lno-1;
 447                         }
 448                         if (last_shown && lno != last_shown + 1)
 449                                 printf(hunk_mark);
 450                         if (!opt->count)
 451                                 show_line(opt, bol, eol, name, lno, ':');
 452                         last_shown = last_hit = lno;
 453                 }
 454                 else if (last_hit &&
 455                          lno <= last_hit + opt->post_context) {
 456                         /* If the last hit is within the post context,
 457                          * we need to show this line.
 458                          */
 459                         if (last_shown && lno != last_shown + 1)
 460                                 printf(hunk_mark);
 461                         show_line(opt, bol, eol, name, lno, '-');
 462                         last_shown = lno;
 463                 }
 464                 if (opt->pre_context) {
 465                         memmove(prev+1, prev,
 466                                 (opt->pre_context-1) * sizeof(*prev));
 467                         prev->bol = bol;
 468                         prev->eol = eol;
 469                 }
 470
 471         next_line:
 472                 bol = eol + 1;
 473                 if (!left)
 474                         break;
 475                 left--;
 476                 lno++;
 477         }
 478
 479         free(prev);
 480
 481         if (opt->status_only)
 482                 return 0;
 483         if (opt->unmatch_name_only) {
 484                 /* We did not see any hit, so we want to show this */
 485                 printf("%s\n", name);
 486                 return 1;
 487         }
 488
 489         /* NEEDSWORK:
 490          * The real "grep -c foo *.c" gives many "bar.c:0" lines,
 491          * which feels mostly useless but sometimes useful.  Maybe
 492          * make it another option?  For now suppress them.
 493          */
 494         if (opt->count && count)
 495                 printf("%s:%u\n", name, count);
 496         return !!last_hit;
 497 }
 498