Ian Hodson | 2ee91b4 | 2012-05-14 12:29:36 +0100 | [diff] [blame] | 1 | // Copyright 2009 The RE2 Authors. All Rights Reserved. |
| 2 | // Use of this source code is governed by a BSD-style |
| 3 | // license that can be found in the LICENSE file. |
| 4 | |
| 5 | #include "util/util.h" |
| 6 | #include "re2/prefilter.h" |
| 7 | #include "re2/re2.h" |
| 8 | #include "re2/unicode_casefold.h" |
| 9 | #include "re2/walker-inl.h" |
| 10 | |
| 11 | namespace re2 { |
| 12 | |
| 13 | static const int Trace = false; |
| 14 | |
| 15 | typedef set<string>::iterator SSIter; |
| 16 | typedef set<string>::const_iterator ConstSSIter; |
| 17 | |
| 18 | static int alloc_id = 100000; // Used for debugging. |
| 19 | // Initializes a Prefilter, allocating subs_ as necessary. |
| 20 | Prefilter::Prefilter(Op op) { |
| 21 | op_ = op; |
| 22 | subs_ = NULL; |
| 23 | if (op_ == AND || op_ == OR) |
| 24 | subs_ = new vector<Prefilter*>; |
| 25 | |
| 26 | alloc_id_ = alloc_id++; |
| 27 | VLOG(10) << "alloc_id: " << alloc_id_; |
| 28 | } |
| 29 | |
| 30 | // Destroys a Prefilter. |
| 31 | Prefilter::~Prefilter() { |
| 32 | VLOG(10) << "Deleted: " << alloc_id_; |
| 33 | if (subs_) { |
| 34 | for (int i = 0; i < subs_->size(); i++) |
| 35 | delete (*subs_)[i]; |
| 36 | delete subs_; |
| 37 | subs_ = NULL; |
| 38 | } |
| 39 | } |
| 40 | |
| 41 | // Simplify if the node is an empty Or or And. |
| 42 | Prefilter* Prefilter::Simplify() { |
| 43 | if (op_ != AND && op_ != OR) { |
| 44 | return this; |
| 45 | } |
| 46 | |
| 47 | // Nothing left in the AND/OR. |
| 48 | if (subs_->size() == 0) { |
| 49 | if (op_ == AND) |
| 50 | op_ = ALL; // AND of nothing is true |
| 51 | else |
| 52 | op_ = NONE; // OR of nothing is false |
| 53 | |
| 54 | return this; |
| 55 | } |
| 56 | |
| 57 | // Just one subnode: throw away wrapper. |
| 58 | if (subs_->size() == 1) { |
| 59 | Prefilter* a = (*subs_)[0]; |
| 60 | subs_->clear(); |
| 61 | delete this; |
| 62 | return a->Simplify(); |
| 63 | } |
| 64 | |
| 65 | return this; |
| 66 | } |
| 67 | |
| 68 | // Combines two Prefilters together to create an "op" (AND or OR). |
| 69 | // The passed Prefilters will be part of the returned Prefilter or deleted. |
| 70 | // Does lots of work to avoid creating unnecessarily complicated structures. |
| 71 | Prefilter* Prefilter::AndOr(Op op, Prefilter* a, Prefilter* b) { |
| 72 | // If a, b can be rewritten as op, do so. |
| 73 | a = a->Simplify(); |
| 74 | b = b->Simplify(); |
| 75 | |
| 76 | // Canonicalize: a->op <= b->op. |
| 77 | if (a->op() > b->op()) { |
| 78 | Prefilter* t = a; |
| 79 | a = b; |
| 80 | b = t; |
| 81 | } |
| 82 | |
| 83 | // Trivial cases. |
| 84 | // ALL AND b = b |
| 85 | // NONE OR b = b |
| 86 | // ALL OR b = ALL |
| 87 | // NONE AND b = NONE |
| 88 | // Don't need to look at b, because of canonicalization above. |
| 89 | // ALL and NONE are smallest opcodes. |
| 90 | if (a->op() == ALL || a->op() == NONE) { |
| 91 | if ((a->op() == ALL && op == AND) || |
| 92 | (a->op() == NONE && op == OR)) { |
| 93 | delete a; |
| 94 | return b; |
| 95 | } else { |
| 96 | delete b; |
| 97 | return a; |
| 98 | } |
| 99 | } |
| 100 | |
| 101 | // If a and b match op, merge their contents. |
| 102 | if (a->op() == op && b->op() == op) { |
| 103 | for (int i = 0; i < b->subs()->size(); i++) { |
| 104 | Prefilter* bb = (*b->subs())[i]; |
| 105 | a->subs()->push_back(bb); |
| 106 | } |
| 107 | b->subs()->clear(); |
| 108 | delete b; |
| 109 | return a; |
| 110 | } |
| 111 | |
| 112 | // If a already has the same op as the op that is under construction |
| 113 | // add in b (similarly if b already has the same op, add in a). |
| 114 | if (b->op() == op) { |
| 115 | Prefilter* t = a; |
| 116 | a = b; |
| 117 | b = t; |
| 118 | } |
| 119 | if (a->op() == op) { |
| 120 | a->subs()->push_back(b); |
| 121 | return a; |
| 122 | } |
| 123 | |
| 124 | // Otherwise just return the op. |
| 125 | Prefilter* c = new Prefilter(op); |
| 126 | c->subs()->push_back(a); |
| 127 | c->subs()->push_back(b); |
| 128 | return c; |
| 129 | } |
| 130 | |
| 131 | Prefilter* Prefilter::And(Prefilter* a, Prefilter* b) { |
| 132 | return AndOr(AND, a, b); |
| 133 | } |
| 134 | |
| 135 | Prefilter* Prefilter::Or(Prefilter* a, Prefilter* b) { |
| 136 | return AndOr(OR, a, b); |
| 137 | } |
| 138 | |
| 139 | static void SimplifyStringSet(set<string> *ss) { |
| 140 | // Now make sure that the strings aren't redundant. For example, if |
| 141 | // we know "ab" is a required string, then it doesn't help at all to |
| 142 | // know that "abc" is also a required string, so delete "abc". This |
| 143 | // is because, when we are performing a string search to filter |
| 144 | // regexps, matching ab will already allow this regexp to be a |
| 145 | // candidate for match, so further matching abc is redundant. |
| 146 | |
| 147 | for (SSIter i = ss->begin(); i != ss->end(); ++i) { |
| 148 | SSIter j = i; |
| 149 | ++j; |
| 150 | while (j != ss->end()) { |
| 151 | // Increment j early so that we can erase the element it points to. |
| 152 | SSIter old_j = j; |
| 153 | ++j; |
| 154 | if (old_j->find(*i) != string::npos) |
| 155 | ss->erase(old_j); |
| 156 | } |
| 157 | } |
| 158 | } |
| 159 | |
| 160 | Prefilter* Prefilter::OrStrings(set<string>* ss) { |
| 161 | SimplifyStringSet(ss); |
| 162 | Prefilter* or_prefilter = NULL; |
| 163 | if (!ss->empty()) { |
| 164 | or_prefilter = new Prefilter(NONE); |
| 165 | for (SSIter i = ss->begin(); i != ss->end(); ++i) |
| 166 | or_prefilter = Or(or_prefilter, FromString(*i)); |
| 167 | } |
| 168 | return or_prefilter; |
| 169 | } |
| 170 | |
| 171 | static Rune ToLowerRune(Rune r) { |
| 172 | if (r < Runeself) { |
| 173 | if ('A' <= r && r <= 'Z') |
| 174 | r += 'a' - 'A'; |
| 175 | return r; |
| 176 | } |
| 177 | |
| 178 | CaseFold *f = LookupCaseFold(unicode_tolower, num_unicode_tolower, r); |
| 179 | if (f == NULL || r < f->lo) |
| 180 | return r; |
| 181 | return ApplyFold(f, r); |
| 182 | } |
| 183 | |
Alexander Gutkin | 0d4c523 | 2013-02-28 13:47:27 +0000 | [diff] [blame] | 184 | static Rune ToLowerRuneLatin1(Rune r) { |
| 185 | if ('A' <= r && r <= 'Z') |
| 186 | r += 'a' - 'A'; |
| 187 | return r; |
| 188 | } |
| 189 | |
Ian Hodson | 2ee91b4 | 2012-05-14 12:29:36 +0100 | [diff] [blame] | 190 | Prefilter* Prefilter::FromString(const string& str) { |
| 191 | Prefilter* m = new Prefilter(Prefilter::ATOM); |
| 192 | m->atom_ = str; |
| 193 | return m; |
| 194 | } |
| 195 | |
| 196 | // Information about a regexp used during computation of Prefilter. |
| 197 | // Can be thought of as information about the set of strings matching |
| 198 | // the given regular expression. |
| 199 | class Prefilter::Info { |
| 200 | public: |
| 201 | Info(); |
| 202 | ~Info(); |
| 203 | |
| 204 | // More constructors. They delete their Info* arguments. |
| 205 | static Info* Alt(Info* a, Info* b); |
| 206 | static Info* Concat(Info* a, Info* b); |
| 207 | static Info* And(Info* a, Info* b); |
| 208 | static Info* Star(Info* a); |
| 209 | static Info* Plus(Info* a); |
| 210 | static Info* Quest(Info* a); |
| 211 | static Info* EmptyString(); |
| 212 | static Info* NoMatch(); |
| 213 | static Info* AnyChar(); |
Alexander Gutkin | 0d4c523 | 2013-02-28 13:47:27 +0000 | [diff] [blame] | 214 | static Info* CClass(CharClass* cc, bool latin1); |
Ian Hodson | 2ee91b4 | 2012-05-14 12:29:36 +0100 | [diff] [blame] | 215 | static Info* Literal(Rune r); |
Alexander Gutkin | 0d4c523 | 2013-02-28 13:47:27 +0000 | [diff] [blame] | 216 | static Info* LiteralLatin1(Rune r); |
Ian Hodson | 2ee91b4 | 2012-05-14 12:29:36 +0100 | [diff] [blame] | 217 | static Info* AnyMatch(); |
| 218 | |
| 219 | // Format Info as a string. |
| 220 | string ToString(); |
| 221 | |
| 222 | // Caller takes ownership of the Prefilter. |
| 223 | Prefilter* TakeMatch(); |
| 224 | |
| 225 | set<string>& exact() { return exact_; } |
| 226 | |
| 227 | bool is_exact() const { return is_exact_; } |
| 228 | |
| 229 | class Walker; |
| 230 | |
| 231 | private: |
| 232 | set<string> exact_; |
| 233 | |
| 234 | // When is_exact_ is true, the strings that match |
| 235 | // are placed in exact_. When it is no longer an exact |
| 236 | // set of strings that match this RE, then is_exact_ |
| 237 | // is false and the match_ contains the required match |
| 238 | // criteria. |
| 239 | bool is_exact_; |
| 240 | |
| 241 | // Accumulated Prefilter query that any |
| 242 | // match for this regexp is guaranteed to match. |
| 243 | Prefilter* match_; |
| 244 | }; |
| 245 | |
| 246 | |
| 247 | Prefilter::Info::Info() |
| 248 | : is_exact_(false), |
| 249 | match_(NULL) { |
| 250 | } |
| 251 | |
| 252 | Prefilter::Info::~Info() { |
| 253 | delete match_; |
| 254 | } |
| 255 | |
| 256 | Prefilter* Prefilter::Info::TakeMatch() { |
| 257 | if (is_exact_) { |
| 258 | match_ = Prefilter::OrStrings(&exact_); |
| 259 | is_exact_ = false; |
| 260 | } |
| 261 | Prefilter* m = match_; |
| 262 | match_ = NULL; |
| 263 | return m; |
| 264 | } |
| 265 | |
| 266 | // Format a Info in string form. |
| 267 | string Prefilter::Info::ToString() { |
| 268 | if (this == NULL) { |
| 269 | // Sometimes when iterating on children of a node, |
| 270 | // some children might have NULL Info. Adding |
| 271 | // the check here for NULL to take care of cases where |
| 272 | // the caller is not checking. |
| 273 | return ""; |
| 274 | } |
| 275 | |
| 276 | if (is_exact_) { |
| 277 | int n = 0; |
| 278 | string s; |
| 279 | for (set<string>::iterator i = exact_.begin(); i != exact_.end(); ++i) { |
| 280 | if (n++ > 0) |
| 281 | s += ","; |
| 282 | s += *i; |
| 283 | } |
| 284 | return s; |
| 285 | } |
| 286 | |
| 287 | if (match_) |
| 288 | return match_->DebugString(); |
| 289 | |
| 290 | return ""; |
| 291 | } |
| 292 | |
| 293 | // Add the strings from src to dst. |
| 294 | static void CopyIn(const set<string>& src, set<string>* dst) { |
| 295 | for (ConstSSIter i = src.begin(); i != src.end(); ++i) |
| 296 | dst->insert(*i); |
| 297 | } |
| 298 | |
| 299 | // Add the cross-product of a and b to dst. |
| 300 | // (For each string i in a and j in b, add i+j.) |
| 301 | static void CrossProduct(const set<string>& a, |
| 302 | const set<string>& b, |
| 303 | set<string>* dst) { |
| 304 | for (ConstSSIter i = a.begin(); i != a.end(); ++i) |
| 305 | for (ConstSSIter j = b.begin(); j != b.end(); ++j) |
| 306 | dst->insert(*i + *j); |
| 307 | } |
| 308 | |
| 309 | // Concats a and b. Requires that both are exact sets. |
| 310 | // Forms an exact set that is a crossproduct of a and b. |
| 311 | Prefilter::Info* Prefilter::Info::Concat(Info* a, Info* b) { |
| 312 | if (a == NULL) |
| 313 | return b; |
| 314 | DCHECK(a->is_exact_); |
| 315 | DCHECK(b && b->is_exact_); |
| 316 | Info *ab = new Info(); |
| 317 | |
| 318 | CrossProduct(a->exact_, b->exact_, &ab->exact_); |
| 319 | ab->is_exact_ = true; |
| 320 | |
| 321 | delete a; |
| 322 | delete b; |
| 323 | return ab; |
| 324 | } |
| 325 | |
| 326 | // Constructs an inexact Info for ab given a and b. |
| 327 | // Used only when a or b is not exact or when the |
| 328 | // exact cross product is likely to be too big. |
| 329 | Prefilter::Info* Prefilter::Info::And(Info* a, Info* b) { |
| 330 | if (a == NULL) |
| 331 | return b; |
| 332 | if (b == NULL) |
| 333 | return a; |
| 334 | |
| 335 | Info *ab = new Info(); |
| 336 | |
| 337 | ab->match_ = Prefilter::And(a->TakeMatch(), b->TakeMatch()); |
| 338 | ab->is_exact_ = false; |
| 339 | delete a; |
| 340 | delete b; |
| 341 | return ab; |
| 342 | } |
| 343 | |
| 344 | // Constructs Info for a|b given a and b. |
| 345 | Prefilter::Info* Prefilter::Info::Alt(Info* a, Info* b) { |
| 346 | Info *ab = new Info(); |
| 347 | |
| 348 | if (a->is_exact_ && b->is_exact_) { |
| 349 | CopyIn(a->exact_, &ab->exact_); |
| 350 | CopyIn(b->exact_, &ab->exact_); |
| 351 | ab->is_exact_ = true; |
| 352 | } else { |
| 353 | // Either a or b has is_exact_ = false. If the other |
| 354 | // one has is_exact_ = true, we move it to match_ and |
| 355 | // then create a OR of a,b. The resulting Info has |
| 356 | // is_exact_ = false. |
| 357 | ab->match_ = Prefilter::Or(a->TakeMatch(), b->TakeMatch()); |
| 358 | ab->is_exact_ = false; |
| 359 | } |
| 360 | |
| 361 | delete a; |
| 362 | delete b; |
| 363 | return ab; |
| 364 | } |
| 365 | |
| 366 | // Constructs Info for a? given a. |
| 367 | Prefilter::Info* Prefilter::Info::Quest(Info *a) { |
| 368 | Info *ab = new Info(); |
| 369 | |
| 370 | ab->is_exact_ = false; |
| 371 | ab->match_ = new Prefilter(ALL); |
| 372 | delete a; |
| 373 | return ab; |
| 374 | } |
| 375 | |
| 376 | // Constructs Info for a* given a. |
| 377 | // Same as a? -- not much to do. |
| 378 | Prefilter::Info* Prefilter::Info::Star(Info *a) { |
| 379 | return Quest(a); |
| 380 | } |
| 381 | |
| 382 | // Constructs Info for a+ given a. If a was exact set, it isn't |
| 383 | // anymore. |
| 384 | Prefilter::Info* Prefilter::Info::Plus(Info *a) { |
| 385 | Info *ab = new Info(); |
| 386 | |
| 387 | ab->match_ = a->TakeMatch(); |
| 388 | ab->is_exact_ = false; |
| 389 | |
| 390 | delete a; |
| 391 | return ab; |
| 392 | } |
| 393 | |
| 394 | static string RuneToString(Rune r) { |
| 395 | char buf[UTFmax]; |
| 396 | int n = runetochar(buf, &r); |
| 397 | return string(buf, n); |
| 398 | } |
| 399 | |
Alexander Gutkin | 0d4c523 | 2013-02-28 13:47:27 +0000 | [diff] [blame] | 400 | static string RuneToStringLatin1(Rune r) { |
| 401 | char c = r & 0xff; |
| 402 | return string(&c, 1); |
| 403 | } |
| 404 | |
Ian Hodson | 2ee91b4 | 2012-05-14 12:29:36 +0100 | [diff] [blame] | 405 | // Constructs Info for literal rune. |
| 406 | Prefilter::Info* Prefilter::Info::Literal(Rune r) { |
| 407 | Info* info = new Info(); |
| 408 | info->exact_.insert(RuneToString(ToLowerRune(r))); |
| 409 | info->is_exact_ = true; |
| 410 | return info; |
| 411 | } |
| 412 | |
Alexander Gutkin | 0d4c523 | 2013-02-28 13:47:27 +0000 | [diff] [blame] | 413 | // Constructs Info for literal rune for Latin1 encoded string. |
| 414 | Prefilter::Info* Prefilter::Info::LiteralLatin1(Rune r) { |
| 415 | Info* info = new Info(); |
| 416 | info->exact_.insert(RuneToStringLatin1(ToLowerRuneLatin1(r))); |
| 417 | info->is_exact_ = true; |
| 418 | return info; |
| 419 | } |
| 420 | |
Ian Hodson | 2ee91b4 | 2012-05-14 12:29:36 +0100 | [diff] [blame] | 421 | // Constructs Info for dot (any character). |
| 422 | Prefilter::Info* Prefilter::Info::AnyChar() { |
| 423 | Prefilter::Info* info = new Prefilter::Info(); |
| 424 | info->match_ = new Prefilter(ALL); |
| 425 | return info; |
| 426 | } |
| 427 | |
| 428 | // Constructs Prefilter::Info for no possible match. |
| 429 | Prefilter::Info* Prefilter::Info::NoMatch() { |
| 430 | Prefilter::Info* info = new Prefilter::Info(); |
| 431 | info->match_ = new Prefilter(NONE); |
| 432 | return info; |
| 433 | } |
| 434 | |
| 435 | // Constructs Prefilter::Info for any possible match. |
| 436 | // This Prefilter::Info is valid for any regular expression, |
| 437 | // since it makes no assertions whatsoever about the |
| 438 | // strings being matched. |
| 439 | Prefilter::Info* Prefilter::Info::AnyMatch() { |
| 440 | Prefilter::Info *info = new Prefilter::Info(); |
| 441 | info->match_ = new Prefilter(ALL); |
| 442 | return info; |
| 443 | } |
| 444 | |
| 445 | // Constructs Prefilter::Info for just the empty string. |
| 446 | Prefilter::Info* Prefilter::Info::EmptyString() { |
| 447 | Prefilter::Info* info = new Prefilter::Info(); |
| 448 | info->is_exact_ = true; |
| 449 | info->exact_.insert(""); |
| 450 | return info; |
| 451 | } |
| 452 | |
| 453 | // Constructs Prefilter::Info for a character class. |
| 454 | typedef CharClass::iterator CCIter; |
Alexander Gutkin | 0d4c523 | 2013-02-28 13:47:27 +0000 | [diff] [blame] | 455 | Prefilter::Info* Prefilter::Info::CClass(CharClass *cc, |
| 456 | bool latin1) { |
Ian Hodson | 2ee91b4 | 2012-05-14 12:29:36 +0100 | [diff] [blame] | 457 | if (Trace) { |
| 458 | VLOG(0) << "CharClassInfo:"; |
| 459 | for (CCIter i = cc->begin(); i != cc->end(); ++i) |
| 460 | VLOG(0) << " " << i->lo << "-" << i->hi; |
| 461 | } |
| 462 | |
| 463 | // If the class is too large, it's okay to overestimate. |
| 464 | if (cc->size() > 10) |
| 465 | return AnyChar(); |
| 466 | |
| 467 | Prefilter::Info *a = new Prefilter::Info(); |
| 468 | for (CCIter i = cc->begin(); i != cc->end(); ++i) |
Alexander Gutkin | 0d4c523 | 2013-02-28 13:47:27 +0000 | [diff] [blame] | 469 | for (Rune r = i->lo; r <= i->hi; r++) { |
| 470 | if (latin1) { |
| 471 | a->exact_.insert(RuneToStringLatin1(ToLowerRuneLatin1(r))); |
| 472 | } else { |
| 473 | a->exact_.insert(RuneToString(ToLowerRune(r))); |
| 474 | } |
| 475 | } |
| 476 | |
Ian Hodson | 2ee91b4 | 2012-05-14 12:29:36 +0100 | [diff] [blame] | 477 | |
| 478 | a->is_exact_ = true; |
| 479 | |
| 480 | if (Trace) { |
| 481 | VLOG(0) << " = " << a->ToString(); |
| 482 | } |
| 483 | |
| 484 | return a; |
| 485 | } |
| 486 | |
| 487 | class Prefilter::Info::Walker : public Regexp::Walker<Prefilter::Info*> { |
| 488 | public: |
Alexander Gutkin | 0d4c523 | 2013-02-28 13:47:27 +0000 | [diff] [blame] | 489 | Walker(bool latin1) : latin1_(latin1) {} |
Ian Hodson | 2ee91b4 | 2012-05-14 12:29:36 +0100 | [diff] [blame] | 490 | |
| 491 | virtual Info* PostVisit( |
| 492 | Regexp* re, Info* parent_arg, |
| 493 | Info* pre_arg, |
| 494 | Info** child_args, int nchild_args); |
| 495 | |
| 496 | virtual Info* ShortVisit( |
| 497 | Regexp* re, |
| 498 | Info* parent_arg); |
| 499 | |
Alexander Gutkin | 0d4c523 | 2013-02-28 13:47:27 +0000 | [diff] [blame] | 500 | bool latin1() { return latin1_; } |
Ian Hodson | 2ee91b4 | 2012-05-14 12:29:36 +0100 | [diff] [blame] | 501 | private: |
Alexander Gutkin | 0d4c523 | 2013-02-28 13:47:27 +0000 | [diff] [blame] | 502 | bool latin1_; |
Ian Hodson | 2ee91b4 | 2012-05-14 12:29:36 +0100 | [diff] [blame] | 503 | DISALLOW_EVIL_CONSTRUCTORS(Walker); |
| 504 | }; |
| 505 | |
| 506 | Prefilter::Info* Prefilter::BuildInfo(Regexp* re) { |
| 507 | if (Trace) { |
| 508 | LOG(INFO) << "BuildPrefilter::Info: " << re->ToString(); |
| 509 | } |
Alexander Gutkin | 0d4c523 | 2013-02-28 13:47:27 +0000 | [diff] [blame] | 510 | |
| 511 | bool latin1 = re->parse_flags() & Regexp::Latin1; |
| 512 | Prefilter::Info::Walker w(latin1); |
Ian Hodson | 2ee91b4 | 2012-05-14 12:29:36 +0100 | [diff] [blame] | 513 | Prefilter::Info* info = w.WalkExponential(re, NULL, 100000); |
| 514 | |
| 515 | if (w.stopped_early()) { |
| 516 | delete info; |
| 517 | return NULL; |
| 518 | } |
| 519 | |
| 520 | return info; |
| 521 | } |
| 522 | |
| 523 | Prefilter::Info* Prefilter::Info::Walker::ShortVisit( |
| 524 | Regexp* re, Prefilter::Info* parent_arg) { |
| 525 | return AnyMatch(); |
| 526 | } |
| 527 | |
| 528 | // Constructs the Prefilter::Info for the given regular expression. |
| 529 | // Assumes re is simplified. |
| 530 | Prefilter::Info* Prefilter::Info::Walker::PostVisit( |
| 531 | Regexp* re, Prefilter::Info* parent_arg, |
| 532 | Prefilter::Info* pre_arg, Prefilter::Info** child_args, |
| 533 | int nchild_args) { |
| 534 | Prefilter::Info *info; |
| 535 | switch (re->op()) { |
| 536 | default: |
| 537 | case kRegexpRepeat: |
| 538 | LOG(DFATAL) << "Bad regexp op " << re->op(); |
| 539 | info = EmptyString(); |
| 540 | break; |
| 541 | |
| 542 | case kRegexpNoMatch: |
| 543 | info = NoMatch(); |
| 544 | break; |
| 545 | |
| 546 | // These ops match the empty string: |
| 547 | case kRegexpEmptyMatch: // anywhere |
| 548 | case kRegexpBeginLine: // at beginning of line |
| 549 | case kRegexpEndLine: // at end of line |
| 550 | case kRegexpBeginText: // at beginning of text |
| 551 | case kRegexpEndText: // at end of text |
| 552 | case kRegexpWordBoundary: // at word boundary |
| 553 | case kRegexpNoWordBoundary: // not at word boundary |
| 554 | info = EmptyString(); |
| 555 | break; |
| 556 | |
| 557 | case kRegexpLiteral: |
Alexander Gutkin | 0d4c523 | 2013-02-28 13:47:27 +0000 | [diff] [blame] | 558 | if (latin1()) { |
| 559 | info = LiteralLatin1(re->rune()); |
| 560 | } |
| 561 | else { |
| 562 | info = Literal(re->rune()); |
| 563 | } |
Ian Hodson | 2ee91b4 | 2012-05-14 12:29:36 +0100 | [diff] [blame] | 564 | break; |
| 565 | |
| 566 | case kRegexpLiteralString: |
| 567 | if (re->nrunes() == 0) { |
| 568 | info = NoMatch(); |
| 569 | break; |
| 570 | } |
Alexander Gutkin | 0d4c523 | 2013-02-28 13:47:27 +0000 | [diff] [blame] | 571 | if (latin1()) { |
| 572 | info = LiteralLatin1(re->runes()[0]); |
| 573 | for (int i = 1; i < re->nrunes(); i++) { |
| 574 | info = Concat(info, LiteralLatin1(re->runes()[i])); |
| 575 | } |
| 576 | } else { |
| 577 | info = Literal(re->runes()[0]); |
| 578 | for (int i = 1; i < re->nrunes(); i++) { |
| 579 | info = Concat(info, Literal(re->runes()[i])); |
| 580 | } |
| 581 | } |
Ian Hodson | 2ee91b4 | 2012-05-14 12:29:36 +0100 | [diff] [blame] | 582 | break; |
| 583 | |
| 584 | case kRegexpConcat: { |
| 585 | // Accumulate in info. |
| 586 | // Exact is concat of recent contiguous exact nodes. |
| 587 | info = NULL; |
| 588 | Info* exact = NULL; |
| 589 | for (int i = 0; i < nchild_args; i++) { |
| 590 | Info* ci = child_args[i]; // child info |
| 591 | if (!ci->is_exact() || |
| 592 | (exact && ci->exact().size() * exact->exact().size() > 16)) { |
| 593 | // Exact run is over. |
| 594 | info = And(info, exact); |
| 595 | exact = NULL; |
| 596 | // Add this child's info. |
| 597 | info = And(info, ci); |
| 598 | } else { |
| 599 | // Append to exact run. |
| 600 | exact = Concat(exact, ci); |
| 601 | } |
| 602 | } |
| 603 | info = And(info, exact); |
| 604 | } |
| 605 | break; |
| 606 | |
| 607 | case kRegexpAlternate: |
| 608 | info = child_args[0]; |
| 609 | for (int i = 1; i < nchild_args; i++) |
| 610 | info = Alt(info, child_args[i]); |
| 611 | VLOG(10) << "Alt: " << info->ToString(); |
| 612 | break; |
| 613 | |
| 614 | case kRegexpStar: |
| 615 | info = Star(child_args[0]); |
| 616 | break; |
| 617 | |
| 618 | case kRegexpQuest: |
| 619 | info = Quest(child_args[0]); |
| 620 | break; |
| 621 | |
| 622 | case kRegexpPlus: |
| 623 | info = Plus(child_args[0]); |
| 624 | break; |
| 625 | |
| 626 | case kRegexpAnyChar: |
| 627 | // Claim nothing, except that it's not empty. |
| 628 | info = AnyChar(); |
| 629 | break; |
| 630 | |
| 631 | case kRegexpCharClass: |
Alexander Gutkin | 0d4c523 | 2013-02-28 13:47:27 +0000 | [diff] [blame] | 632 | info = CClass(re->cc(), latin1()); |
Ian Hodson | 2ee91b4 | 2012-05-14 12:29:36 +0100 | [diff] [blame] | 633 | break; |
| 634 | |
| 635 | case kRegexpCapture: |
| 636 | // These don't affect the set of matching strings. |
| 637 | info = child_args[0]; |
| 638 | break; |
| 639 | } |
| 640 | |
| 641 | if (Trace) { |
| 642 | VLOG(0) << "BuildInfo " << re->ToString() |
| 643 | << ": " << info->ToString(); |
| 644 | } |
| 645 | |
| 646 | return info; |
| 647 | } |
| 648 | |
| 649 | |
| 650 | Prefilter* Prefilter::FromRegexp(Regexp* re) { |
| 651 | if (re == NULL) |
| 652 | return NULL; |
| 653 | |
| 654 | Regexp* simple = re->Simplify(); |
| 655 | Prefilter::Info *info = BuildInfo(simple); |
| 656 | |
| 657 | simple->Decref(); |
| 658 | if (info == NULL) |
| 659 | return NULL; |
| 660 | |
| 661 | Prefilter* m = info->TakeMatch(); |
| 662 | |
| 663 | delete info; |
| 664 | return m; |
| 665 | } |
| 666 | |
| 667 | string Prefilter::DebugString() const { |
| 668 | if (this == NULL) |
| 669 | return "<nil>"; |
| 670 | |
| 671 | switch (op_) { |
| 672 | default: |
| 673 | LOG(DFATAL) << "Bad op in Prefilter::DebugString: " << op_; |
| 674 | return StringPrintf("op%d", op_); |
| 675 | case NONE: |
| 676 | return "*no-matches*"; |
| 677 | case ATOM: |
| 678 | return atom_; |
| 679 | case ALL: |
| 680 | return ""; |
| 681 | case AND: { |
| 682 | string s = ""; |
| 683 | for (int i = 0; i < subs_->size(); i++) { |
| 684 | if (i > 0) |
| 685 | s += " "; |
| 686 | s += (*subs_)[i]->DebugString(); |
| 687 | } |
| 688 | return s; |
| 689 | } |
| 690 | case OR: { |
| 691 | string s = "("; |
| 692 | for (int i = 0; i < subs_->size(); i++) { |
| 693 | if (i > 0) |
| 694 | s += "|"; |
| 695 | s += (*subs_)[i]->DebugString(); |
| 696 | } |
| 697 | s += ")"; |
| 698 | return s; |
| 699 | } |
| 700 | } |
| 701 | } |
| 702 | |
| 703 | Prefilter* Prefilter::FromRE2(const RE2* re2) { |
| 704 | if (re2 == NULL) |
| 705 | return NULL; |
| 706 | |
| 707 | Regexp* regexp = re2->Regexp(); |
| 708 | if (regexp == NULL) |
| 709 | return NULL; |
| 710 | |
| 711 | return FromRegexp(regexp); |
| 712 | } |
| 713 | |
| 714 | |
| 715 | } // namespace re2 |