Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame^] | 1 | // Copyright 2016 the V8 project authors. All rights reserved. |
| 2 | // Use of this source code is governed by a BSD-style license that can be |
| 3 | // found in the LICENSE file. |
| 4 | |
| 5 | #include "src/regexp/regexp-parser.h" |
| 6 | |
| 7 | #include "src/char-predicates-inl.h" |
| 8 | #include "src/factory.h" |
| 9 | #include "src/isolate.h" |
| 10 | #include "src/objects-inl.h" |
| 11 | #include "src/regexp/jsregexp.h" |
| 12 | #include "src/utils.h" |
| 13 | |
| 14 | namespace v8 { |
| 15 | namespace internal { |
| 16 | |
| 17 | RegExpParser::RegExpParser(FlatStringReader* in, Handle<String>* error, |
| 18 | bool multiline, bool unicode, Isolate* isolate, |
| 19 | Zone* zone) |
| 20 | : isolate_(isolate), |
| 21 | zone_(zone), |
| 22 | error_(error), |
| 23 | captures_(NULL), |
| 24 | in_(in), |
| 25 | current_(kEndMarker), |
| 26 | next_pos_(0), |
| 27 | captures_started_(0), |
| 28 | capture_count_(0), |
| 29 | has_more_(true), |
| 30 | multiline_(multiline), |
| 31 | unicode_(unicode), |
| 32 | simple_(false), |
| 33 | contains_anchor_(false), |
| 34 | is_scanned_for_captures_(false), |
| 35 | failed_(false) { |
| 36 | Advance(); |
| 37 | } |
| 38 | |
| 39 | |
| 40 | uc32 RegExpParser::Next() { |
| 41 | if (has_next()) { |
| 42 | return in()->Get(next_pos_); |
| 43 | } else { |
| 44 | return kEndMarker; |
| 45 | } |
| 46 | } |
| 47 | |
| 48 | |
| 49 | void RegExpParser::Advance() { |
| 50 | if (next_pos_ < in()->length()) { |
| 51 | StackLimitCheck check(isolate()); |
| 52 | if (check.HasOverflowed()) { |
| 53 | ReportError(CStrVector(Isolate::kStackOverflowMessage)); |
| 54 | } else if (zone()->excess_allocation()) { |
| 55 | ReportError(CStrVector("Regular expression too large")); |
| 56 | } else { |
| 57 | current_ = in()->Get(next_pos_); |
| 58 | next_pos_++; |
| 59 | // Read the whole surrogate pair in case of unicode flag, if possible. |
| 60 | if (unicode_ && next_pos_ < in()->length() && |
| 61 | unibrow::Utf16::IsLeadSurrogate(static_cast<uc16>(current_))) { |
| 62 | uc16 trail = in()->Get(next_pos_); |
| 63 | if (unibrow::Utf16::IsTrailSurrogate(trail)) { |
| 64 | current_ = unibrow::Utf16::CombineSurrogatePair( |
| 65 | static_cast<uc16>(current_), trail); |
| 66 | next_pos_++; |
| 67 | } |
| 68 | } |
| 69 | } |
| 70 | } else { |
| 71 | current_ = kEndMarker; |
| 72 | // Advance so that position() points to 1-after-the-last-character. This is |
| 73 | // important so that Reset() to this position works correctly. |
| 74 | next_pos_ = in()->length() + 1; |
| 75 | has_more_ = false; |
| 76 | } |
| 77 | } |
| 78 | |
| 79 | |
| 80 | void RegExpParser::Reset(int pos) { |
| 81 | next_pos_ = pos; |
| 82 | has_more_ = (pos < in()->length()); |
| 83 | Advance(); |
| 84 | } |
| 85 | |
| 86 | |
| 87 | void RegExpParser::Advance(int dist) { |
| 88 | next_pos_ += dist - 1; |
| 89 | Advance(); |
| 90 | } |
| 91 | |
| 92 | |
| 93 | bool RegExpParser::simple() { return simple_; } |
| 94 | |
| 95 | |
| 96 | bool RegExpParser::IsSyntaxCharacter(uc32 c) { |
| 97 | return c == '^' || c == '$' || c == '\\' || c == '.' || c == '*' || |
| 98 | c == '+' || c == '?' || c == '(' || c == ')' || c == '[' || c == ']' || |
| 99 | c == '{' || c == '}' || c == '|'; |
| 100 | } |
| 101 | |
| 102 | |
| 103 | RegExpTree* RegExpParser::ReportError(Vector<const char> message) { |
| 104 | failed_ = true; |
| 105 | *error_ = isolate()->factory()->NewStringFromAscii(message).ToHandleChecked(); |
| 106 | // Zip to the end to make sure the no more input is read. |
| 107 | current_ = kEndMarker; |
| 108 | next_pos_ = in()->length(); |
| 109 | return NULL; |
| 110 | } |
| 111 | |
| 112 | |
| 113 | #define CHECK_FAILED /**/); \ |
| 114 | if (failed_) return NULL; \ |
| 115 | ((void)0 |
| 116 | |
| 117 | |
| 118 | // Pattern :: |
| 119 | // Disjunction |
| 120 | RegExpTree* RegExpParser::ParsePattern() { |
| 121 | RegExpTree* result = ParseDisjunction(CHECK_FAILED); |
| 122 | DCHECK(!has_more()); |
| 123 | // If the result of parsing is a literal string atom, and it has the |
| 124 | // same length as the input, then the atom is identical to the input. |
| 125 | if (result->IsAtom() && result->AsAtom()->length() == in()->length()) { |
| 126 | simple_ = true; |
| 127 | } |
| 128 | return result; |
| 129 | } |
| 130 | |
| 131 | |
| 132 | // Disjunction :: |
| 133 | // Alternative |
| 134 | // Alternative | Disjunction |
| 135 | // Alternative :: |
| 136 | // [empty] |
| 137 | // Term Alternative |
| 138 | // Term :: |
| 139 | // Assertion |
| 140 | // Atom |
| 141 | // Atom Quantifier |
| 142 | RegExpTree* RegExpParser::ParseDisjunction() { |
| 143 | // Used to store current state while parsing subexpressions. |
| 144 | RegExpParserState initial_state(NULL, INITIAL, RegExpLookaround::LOOKAHEAD, 0, |
| 145 | zone()); |
| 146 | RegExpParserState* state = &initial_state; |
| 147 | // Cache the builder in a local variable for quick access. |
| 148 | RegExpBuilder* builder = initial_state.builder(); |
| 149 | while (true) { |
| 150 | switch (current()) { |
| 151 | case kEndMarker: |
| 152 | if (state->IsSubexpression()) { |
| 153 | // Inside a parenthesized group when hitting end of input. |
| 154 | ReportError(CStrVector("Unterminated group") CHECK_FAILED); |
| 155 | } |
| 156 | DCHECK_EQ(INITIAL, state->group_type()); |
| 157 | // Parsing completed successfully. |
| 158 | return builder->ToRegExp(); |
| 159 | case ')': { |
| 160 | if (!state->IsSubexpression()) { |
| 161 | ReportError(CStrVector("Unmatched ')'") CHECK_FAILED); |
| 162 | } |
| 163 | DCHECK_NE(INITIAL, state->group_type()); |
| 164 | |
| 165 | Advance(); |
| 166 | // End disjunction parsing and convert builder content to new single |
| 167 | // regexp atom. |
| 168 | RegExpTree* body = builder->ToRegExp(); |
| 169 | |
| 170 | int end_capture_index = captures_started(); |
| 171 | |
| 172 | int capture_index = state->capture_index(); |
| 173 | SubexpressionType group_type = state->group_type(); |
| 174 | |
| 175 | // Build result of subexpression. |
| 176 | if (group_type == CAPTURE) { |
| 177 | RegExpCapture* capture = GetCapture(capture_index); |
| 178 | capture->set_body(body); |
| 179 | body = capture; |
| 180 | } else if (group_type != GROUPING) { |
| 181 | DCHECK(group_type == POSITIVE_LOOKAROUND || |
| 182 | group_type == NEGATIVE_LOOKAROUND); |
| 183 | bool is_positive = (group_type == POSITIVE_LOOKAROUND); |
| 184 | body = new (zone()) RegExpLookaround( |
| 185 | body, is_positive, end_capture_index - capture_index, |
| 186 | capture_index, state->lookaround_type()); |
| 187 | } |
| 188 | |
| 189 | // Restore previous state. |
| 190 | state = state->previous_state(); |
| 191 | builder = state->builder(); |
| 192 | |
| 193 | builder->AddAtom(body); |
| 194 | // For compatability with JSC and ES3, we allow quantifiers after |
| 195 | // lookaheads, and break in all cases. |
| 196 | break; |
| 197 | } |
| 198 | case '|': { |
| 199 | Advance(); |
| 200 | builder->NewAlternative(); |
| 201 | continue; |
| 202 | } |
| 203 | case '*': |
| 204 | case '+': |
| 205 | case '?': |
| 206 | return ReportError(CStrVector("Nothing to repeat")); |
| 207 | case '^': { |
| 208 | Advance(); |
| 209 | if (multiline_) { |
| 210 | builder->AddAssertion( |
| 211 | new (zone()) RegExpAssertion(RegExpAssertion::START_OF_LINE)); |
| 212 | } else { |
| 213 | builder->AddAssertion( |
| 214 | new (zone()) RegExpAssertion(RegExpAssertion::START_OF_INPUT)); |
| 215 | set_contains_anchor(); |
| 216 | } |
| 217 | continue; |
| 218 | } |
| 219 | case '$': { |
| 220 | Advance(); |
| 221 | RegExpAssertion::AssertionType assertion_type = |
| 222 | multiline_ ? RegExpAssertion::END_OF_LINE |
| 223 | : RegExpAssertion::END_OF_INPUT; |
| 224 | builder->AddAssertion(new (zone()) RegExpAssertion(assertion_type)); |
| 225 | continue; |
| 226 | } |
| 227 | case '.': { |
| 228 | Advance(); |
| 229 | // everything except \x0a, \x0d, \u2028 and \u2029 |
| 230 | ZoneList<CharacterRange>* ranges = |
| 231 | new (zone()) ZoneList<CharacterRange>(2, zone()); |
| 232 | CharacterRange::AddClassEscape('.', ranges, zone()); |
| 233 | RegExpTree* atom = new (zone()) RegExpCharacterClass(ranges, false); |
| 234 | builder->AddAtom(atom); |
| 235 | break; |
| 236 | } |
| 237 | case '(': { |
| 238 | SubexpressionType subexpr_type = CAPTURE; |
| 239 | RegExpLookaround::Type lookaround_type = state->lookaround_type(); |
| 240 | Advance(); |
| 241 | if (current() == '?') { |
| 242 | switch (Next()) { |
| 243 | case ':': |
| 244 | subexpr_type = GROUPING; |
| 245 | break; |
| 246 | case '=': |
| 247 | lookaround_type = RegExpLookaround::LOOKAHEAD; |
| 248 | subexpr_type = POSITIVE_LOOKAROUND; |
| 249 | break; |
| 250 | case '!': |
| 251 | lookaround_type = RegExpLookaround::LOOKAHEAD; |
| 252 | subexpr_type = NEGATIVE_LOOKAROUND; |
| 253 | break; |
| 254 | case '<': |
| 255 | if (FLAG_harmony_regexp_lookbehind) { |
| 256 | Advance(); |
| 257 | lookaround_type = RegExpLookaround::LOOKBEHIND; |
| 258 | if (Next() == '=') { |
| 259 | subexpr_type = POSITIVE_LOOKAROUND; |
| 260 | break; |
| 261 | } else if (Next() == '!') { |
| 262 | subexpr_type = NEGATIVE_LOOKAROUND; |
| 263 | break; |
| 264 | } |
| 265 | } |
| 266 | // Fall through. |
| 267 | default: |
| 268 | ReportError(CStrVector("Invalid group") CHECK_FAILED); |
| 269 | break; |
| 270 | } |
| 271 | Advance(2); |
| 272 | } else { |
| 273 | if (captures_started_ >= kMaxCaptures) { |
| 274 | ReportError(CStrVector("Too many captures") CHECK_FAILED); |
| 275 | } |
| 276 | captures_started_++; |
| 277 | } |
| 278 | // Store current state and begin new disjunction parsing. |
| 279 | state = new (zone()) RegExpParserState( |
| 280 | state, subexpr_type, lookaround_type, captures_started_, zone()); |
| 281 | builder = state->builder(); |
| 282 | continue; |
| 283 | } |
| 284 | case '[': { |
| 285 | RegExpTree* atom = ParseCharacterClass(CHECK_FAILED); |
| 286 | builder->AddAtom(atom); |
| 287 | break; |
| 288 | } |
| 289 | // Atom :: |
| 290 | // \ AtomEscape |
| 291 | case '\\': |
| 292 | switch (Next()) { |
| 293 | case kEndMarker: |
| 294 | return ReportError(CStrVector("\\ at end of pattern")); |
| 295 | case 'b': |
| 296 | Advance(2); |
| 297 | builder->AddAssertion( |
| 298 | new (zone()) RegExpAssertion(RegExpAssertion::BOUNDARY)); |
| 299 | continue; |
| 300 | case 'B': |
| 301 | Advance(2); |
| 302 | builder->AddAssertion( |
| 303 | new (zone()) RegExpAssertion(RegExpAssertion::NON_BOUNDARY)); |
| 304 | continue; |
| 305 | // AtomEscape :: |
| 306 | // CharacterClassEscape |
| 307 | // |
| 308 | // CharacterClassEscape :: one of |
| 309 | // d D s S w W |
| 310 | case 'd': |
| 311 | case 'D': |
| 312 | case 's': |
| 313 | case 'S': |
| 314 | case 'w': |
| 315 | case 'W': { |
| 316 | uc32 c = Next(); |
| 317 | Advance(2); |
| 318 | ZoneList<CharacterRange>* ranges = |
| 319 | new (zone()) ZoneList<CharacterRange>(2, zone()); |
| 320 | CharacterRange::AddClassEscape(c, ranges, zone()); |
| 321 | RegExpTree* atom = new (zone()) RegExpCharacterClass(ranges, false); |
| 322 | builder->AddAtom(atom); |
| 323 | break; |
| 324 | } |
| 325 | case '1': |
| 326 | case '2': |
| 327 | case '3': |
| 328 | case '4': |
| 329 | case '5': |
| 330 | case '6': |
| 331 | case '7': |
| 332 | case '8': |
| 333 | case '9': { |
| 334 | int index = 0; |
| 335 | if (ParseBackReferenceIndex(&index)) { |
| 336 | if (state->IsInsideCaptureGroup(index)) { |
| 337 | // The back reference is inside the capture group it refers to. |
| 338 | // Nothing can possibly have been captured yet, so we use empty |
| 339 | // instead. This ensures that, when checking a back reference, |
| 340 | // the capture registers of the referenced capture are either |
| 341 | // both set or both cleared. |
| 342 | builder->AddEmpty(); |
| 343 | } else { |
| 344 | RegExpCapture* capture = GetCapture(index); |
| 345 | RegExpTree* atom = new (zone()) RegExpBackReference(capture); |
| 346 | builder->AddAtom(atom); |
| 347 | } |
| 348 | break; |
| 349 | } |
| 350 | uc32 first_digit = Next(); |
| 351 | if (first_digit == '8' || first_digit == '9') { |
| 352 | // If the 'u' flag is present, only syntax characters can be |
| 353 | // escaped, |
| 354 | // no other identity escapes are allowed. If the 'u' flag is not |
| 355 | // present, all identity escapes are allowed. |
| 356 | if (!unicode_) { |
| 357 | builder->AddCharacter(first_digit); |
| 358 | Advance(2); |
| 359 | } else { |
| 360 | return ReportError(CStrVector("Invalid escape")); |
| 361 | } |
| 362 | break; |
| 363 | } |
| 364 | } |
| 365 | // FALLTHROUGH |
| 366 | case '0': { |
| 367 | Advance(); |
| 368 | uc32 octal = ParseOctalLiteral(); |
| 369 | builder->AddCharacter(octal); |
| 370 | break; |
| 371 | } |
| 372 | // ControlEscape :: one of |
| 373 | // f n r t v |
| 374 | case 'f': |
| 375 | Advance(2); |
| 376 | builder->AddCharacter('\f'); |
| 377 | break; |
| 378 | case 'n': |
| 379 | Advance(2); |
| 380 | builder->AddCharacter('\n'); |
| 381 | break; |
| 382 | case 'r': |
| 383 | Advance(2); |
| 384 | builder->AddCharacter('\r'); |
| 385 | break; |
| 386 | case 't': |
| 387 | Advance(2); |
| 388 | builder->AddCharacter('\t'); |
| 389 | break; |
| 390 | case 'v': |
| 391 | Advance(2); |
| 392 | builder->AddCharacter('\v'); |
| 393 | break; |
| 394 | case 'c': { |
| 395 | Advance(); |
| 396 | uc32 controlLetter = Next(); |
| 397 | // Special case if it is an ASCII letter. |
| 398 | // Convert lower case letters to uppercase. |
| 399 | uc32 letter = controlLetter & ~('a' ^ 'A'); |
| 400 | if (letter < 'A' || 'Z' < letter) { |
| 401 | // controlLetter is not in range 'A'-'Z' or 'a'-'z'. |
| 402 | // This is outside the specification. We match JSC in |
| 403 | // reading the backslash as a literal character instead |
| 404 | // of as starting an escape. |
| 405 | builder->AddCharacter('\\'); |
| 406 | } else { |
| 407 | Advance(2); |
| 408 | builder->AddCharacter(controlLetter & 0x1f); |
| 409 | } |
| 410 | break; |
| 411 | } |
| 412 | case 'x': { |
| 413 | Advance(2); |
| 414 | uc32 value; |
| 415 | if (ParseHexEscape(2, &value)) { |
| 416 | builder->AddCharacter(value); |
| 417 | } else if (!unicode_) { |
| 418 | builder->AddCharacter('x'); |
| 419 | } else { |
| 420 | // If the 'u' flag is present, invalid escapes are not treated as |
| 421 | // identity escapes. |
| 422 | return ReportError(CStrVector("Invalid escape")); |
| 423 | } |
| 424 | break; |
| 425 | } |
| 426 | case 'u': { |
| 427 | Advance(2); |
| 428 | uc32 value; |
| 429 | if (ParseUnicodeEscape(&value)) { |
| 430 | builder->AddUnicodeCharacter(value); |
| 431 | } else if (!unicode_) { |
| 432 | builder->AddCharacter('u'); |
| 433 | } else { |
| 434 | // If the 'u' flag is present, invalid escapes are not treated as |
| 435 | // identity escapes. |
| 436 | return ReportError(CStrVector("Invalid unicode escape")); |
| 437 | } |
| 438 | break; |
| 439 | } |
| 440 | default: |
| 441 | Advance(); |
| 442 | // If the 'u' flag is present, only syntax characters can be |
| 443 | // escaped, no |
| 444 | // other identity escapes are allowed. If the 'u' flag is not |
| 445 | // present, |
| 446 | // all identity escapes are allowed. |
| 447 | if (!unicode_ || IsSyntaxCharacter(current())) { |
| 448 | builder->AddCharacter(current()); |
| 449 | Advance(); |
| 450 | } else { |
| 451 | return ReportError(CStrVector("Invalid escape")); |
| 452 | } |
| 453 | break; |
| 454 | } |
| 455 | break; |
| 456 | case '{': { |
| 457 | int dummy; |
| 458 | if (ParseIntervalQuantifier(&dummy, &dummy)) { |
| 459 | ReportError(CStrVector("Nothing to repeat") CHECK_FAILED); |
| 460 | } |
| 461 | // fallthrough |
| 462 | } |
| 463 | default: |
| 464 | builder->AddUnicodeCharacter(current()); |
| 465 | Advance(); |
| 466 | break; |
| 467 | } // end switch(current()) |
| 468 | |
| 469 | int min; |
| 470 | int max; |
| 471 | switch (current()) { |
| 472 | // QuantifierPrefix :: |
| 473 | // * |
| 474 | // + |
| 475 | // ? |
| 476 | // { |
| 477 | case '*': |
| 478 | min = 0; |
| 479 | max = RegExpTree::kInfinity; |
| 480 | Advance(); |
| 481 | break; |
| 482 | case '+': |
| 483 | min = 1; |
| 484 | max = RegExpTree::kInfinity; |
| 485 | Advance(); |
| 486 | break; |
| 487 | case '?': |
| 488 | min = 0; |
| 489 | max = 1; |
| 490 | Advance(); |
| 491 | break; |
| 492 | case '{': |
| 493 | if (ParseIntervalQuantifier(&min, &max)) { |
| 494 | if (max < min) { |
| 495 | ReportError(CStrVector("numbers out of order in {} quantifier.") |
| 496 | CHECK_FAILED); |
| 497 | } |
| 498 | break; |
| 499 | } else { |
| 500 | continue; |
| 501 | } |
| 502 | default: |
| 503 | continue; |
| 504 | } |
| 505 | RegExpQuantifier::QuantifierType quantifier_type = RegExpQuantifier::GREEDY; |
| 506 | if (current() == '?') { |
| 507 | quantifier_type = RegExpQuantifier::NON_GREEDY; |
| 508 | Advance(); |
| 509 | } else if (FLAG_regexp_possessive_quantifier && current() == '+') { |
| 510 | // FLAG_regexp_possessive_quantifier is a debug-only flag. |
| 511 | quantifier_type = RegExpQuantifier::POSSESSIVE; |
| 512 | Advance(); |
| 513 | } |
| 514 | builder->AddQuantifierToAtom(min, max, quantifier_type); |
| 515 | } |
| 516 | } |
| 517 | |
| 518 | |
| 519 | #ifdef DEBUG |
| 520 | // Currently only used in an DCHECK. |
| 521 | static bool IsSpecialClassEscape(uc32 c) { |
| 522 | switch (c) { |
| 523 | case 'd': |
| 524 | case 'D': |
| 525 | case 's': |
| 526 | case 'S': |
| 527 | case 'w': |
| 528 | case 'W': |
| 529 | return true; |
| 530 | default: |
| 531 | return false; |
| 532 | } |
| 533 | } |
| 534 | #endif |
| 535 | |
| 536 | |
| 537 | // In order to know whether an escape is a backreference or not we have to scan |
| 538 | // the entire regexp and find the number of capturing parentheses. However we |
| 539 | // don't want to scan the regexp twice unless it is necessary. This mini-parser |
| 540 | // is called when needed. It can see the difference between capturing and |
| 541 | // noncapturing parentheses and can skip character classes and backslash-escaped |
| 542 | // characters. |
| 543 | void RegExpParser::ScanForCaptures() { |
| 544 | // Start with captures started previous to current position |
| 545 | int capture_count = captures_started(); |
| 546 | // Add count of captures after this position. |
| 547 | int n; |
| 548 | while ((n = current()) != kEndMarker) { |
| 549 | Advance(); |
| 550 | switch (n) { |
| 551 | case '\\': |
| 552 | Advance(); |
| 553 | break; |
| 554 | case '[': { |
| 555 | int c; |
| 556 | while ((c = current()) != kEndMarker) { |
| 557 | Advance(); |
| 558 | if (c == '\\') { |
| 559 | Advance(); |
| 560 | } else { |
| 561 | if (c == ']') break; |
| 562 | } |
| 563 | } |
| 564 | break; |
| 565 | } |
| 566 | case '(': |
| 567 | if (current() != '?') capture_count++; |
| 568 | break; |
| 569 | } |
| 570 | } |
| 571 | capture_count_ = capture_count; |
| 572 | is_scanned_for_captures_ = true; |
| 573 | } |
| 574 | |
| 575 | |
| 576 | bool RegExpParser::ParseBackReferenceIndex(int* index_out) { |
| 577 | DCHECK_EQ('\\', current()); |
| 578 | DCHECK('1' <= Next() && Next() <= '9'); |
| 579 | // Try to parse a decimal literal that is no greater than the total number |
| 580 | // of left capturing parentheses in the input. |
| 581 | int start = position(); |
| 582 | int value = Next() - '0'; |
| 583 | Advance(2); |
| 584 | while (true) { |
| 585 | uc32 c = current(); |
| 586 | if (IsDecimalDigit(c)) { |
| 587 | value = 10 * value + (c - '0'); |
| 588 | if (value > kMaxCaptures) { |
| 589 | Reset(start); |
| 590 | return false; |
| 591 | } |
| 592 | Advance(); |
| 593 | } else { |
| 594 | break; |
| 595 | } |
| 596 | } |
| 597 | if (value > captures_started()) { |
| 598 | if (!is_scanned_for_captures_) { |
| 599 | int saved_position = position(); |
| 600 | ScanForCaptures(); |
| 601 | Reset(saved_position); |
| 602 | } |
| 603 | if (value > capture_count_) { |
| 604 | Reset(start); |
| 605 | return false; |
| 606 | } |
| 607 | } |
| 608 | *index_out = value; |
| 609 | return true; |
| 610 | } |
| 611 | |
| 612 | |
| 613 | RegExpCapture* RegExpParser::GetCapture(int index) { |
| 614 | // The index for the capture groups are one-based. Its index in the list is |
| 615 | // zero-based. |
| 616 | int know_captures = |
| 617 | is_scanned_for_captures_ ? capture_count_ : captures_started_; |
| 618 | DCHECK(index <= know_captures); |
| 619 | if (captures_ == NULL) { |
| 620 | captures_ = new (zone()) ZoneList<RegExpCapture*>(know_captures, zone()); |
| 621 | } |
| 622 | while (captures_->length() < know_captures) { |
| 623 | captures_->Add(new (zone()) RegExpCapture(captures_->length() + 1), zone()); |
| 624 | } |
| 625 | return captures_->at(index - 1); |
| 626 | } |
| 627 | |
| 628 | |
| 629 | bool RegExpParser::RegExpParserState::IsInsideCaptureGroup(int index) { |
| 630 | for (RegExpParserState* s = this; s != NULL; s = s->previous_state()) { |
| 631 | if (s->group_type() != CAPTURE) continue; |
| 632 | // Return true if we found the matching capture index. |
| 633 | if (index == s->capture_index()) return true; |
| 634 | // Abort if index is larger than what has been parsed up till this state. |
| 635 | if (index > s->capture_index()) return false; |
| 636 | } |
| 637 | return false; |
| 638 | } |
| 639 | |
| 640 | |
| 641 | // QuantifierPrefix :: |
| 642 | // { DecimalDigits } |
| 643 | // { DecimalDigits , } |
| 644 | // { DecimalDigits , DecimalDigits } |
| 645 | // |
| 646 | // Returns true if parsing succeeds, and set the min_out and max_out |
| 647 | // values. Values are truncated to RegExpTree::kInfinity if they overflow. |
| 648 | bool RegExpParser::ParseIntervalQuantifier(int* min_out, int* max_out) { |
| 649 | DCHECK_EQ(current(), '{'); |
| 650 | int start = position(); |
| 651 | Advance(); |
| 652 | int min = 0; |
| 653 | if (!IsDecimalDigit(current())) { |
| 654 | Reset(start); |
| 655 | return false; |
| 656 | } |
| 657 | while (IsDecimalDigit(current())) { |
| 658 | int next = current() - '0'; |
| 659 | if (min > (RegExpTree::kInfinity - next) / 10) { |
| 660 | // Overflow. Skip past remaining decimal digits and return -1. |
| 661 | do { |
| 662 | Advance(); |
| 663 | } while (IsDecimalDigit(current())); |
| 664 | min = RegExpTree::kInfinity; |
| 665 | break; |
| 666 | } |
| 667 | min = 10 * min + next; |
| 668 | Advance(); |
| 669 | } |
| 670 | int max = 0; |
| 671 | if (current() == '}') { |
| 672 | max = min; |
| 673 | Advance(); |
| 674 | } else if (current() == ',') { |
| 675 | Advance(); |
| 676 | if (current() == '}') { |
| 677 | max = RegExpTree::kInfinity; |
| 678 | Advance(); |
| 679 | } else { |
| 680 | while (IsDecimalDigit(current())) { |
| 681 | int next = current() - '0'; |
| 682 | if (max > (RegExpTree::kInfinity - next) / 10) { |
| 683 | do { |
| 684 | Advance(); |
| 685 | } while (IsDecimalDigit(current())); |
| 686 | max = RegExpTree::kInfinity; |
| 687 | break; |
| 688 | } |
| 689 | max = 10 * max + next; |
| 690 | Advance(); |
| 691 | } |
| 692 | if (current() != '}') { |
| 693 | Reset(start); |
| 694 | return false; |
| 695 | } |
| 696 | Advance(); |
| 697 | } |
| 698 | } else { |
| 699 | Reset(start); |
| 700 | return false; |
| 701 | } |
| 702 | *min_out = min; |
| 703 | *max_out = max; |
| 704 | return true; |
| 705 | } |
| 706 | |
| 707 | |
| 708 | uc32 RegExpParser::ParseOctalLiteral() { |
| 709 | DCHECK(('0' <= current() && current() <= '7') || current() == kEndMarker); |
| 710 | // For compatibility with some other browsers (not all), we parse |
| 711 | // up to three octal digits with a value below 256. |
| 712 | uc32 value = current() - '0'; |
| 713 | Advance(); |
| 714 | if ('0' <= current() && current() <= '7') { |
| 715 | value = value * 8 + current() - '0'; |
| 716 | Advance(); |
| 717 | if (value < 32 && '0' <= current() && current() <= '7') { |
| 718 | value = value * 8 + current() - '0'; |
| 719 | Advance(); |
| 720 | } |
| 721 | } |
| 722 | return value; |
| 723 | } |
| 724 | |
| 725 | |
| 726 | bool RegExpParser::ParseHexEscape(int length, uc32* value) { |
| 727 | int start = position(); |
| 728 | uc32 val = 0; |
| 729 | for (int i = 0; i < length; ++i) { |
| 730 | uc32 c = current(); |
| 731 | int d = HexValue(c); |
| 732 | if (d < 0) { |
| 733 | Reset(start); |
| 734 | return false; |
| 735 | } |
| 736 | val = val * 16 + d; |
| 737 | Advance(); |
| 738 | } |
| 739 | *value = val; |
| 740 | return true; |
| 741 | } |
| 742 | |
| 743 | |
| 744 | bool RegExpParser::ParseUnicodeEscape(uc32* value) { |
| 745 | // Accept both \uxxxx and \u{xxxxxx} (if harmony unicode escapes are |
| 746 | // allowed). In the latter case, the number of hex digits between { } is |
| 747 | // arbitrary. \ and u have already been read. |
| 748 | if (current() == '{' && unicode_) { |
| 749 | int start = position(); |
| 750 | Advance(); |
| 751 | if (ParseUnlimitedLengthHexNumber(0x10ffff, value)) { |
| 752 | if (current() == '}') { |
| 753 | Advance(); |
| 754 | return true; |
| 755 | } |
| 756 | } |
| 757 | Reset(start); |
| 758 | return false; |
| 759 | } |
| 760 | // \u but no {, or \u{...} escapes not allowed. |
| 761 | return ParseHexEscape(4, value); |
| 762 | } |
| 763 | |
| 764 | |
| 765 | bool RegExpParser::ParseUnlimitedLengthHexNumber(int max_value, uc32* value) { |
| 766 | uc32 x = 0; |
| 767 | int d = HexValue(current()); |
| 768 | if (d < 0) { |
| 769 | return false; |
| 770 | } |
| 771 | while (d >= 0) { |
| 772 | x = x * 16 + d; |
| 773 | if (x > max_value) { |
| 774 | return false; |
| 775 | } |
| 776 | Advance(); |
| 777 | d = HexValue(current()); |
| 778 | } |
| 779 | *value = x; |
| 780 | return true; |
| 781 | } |
| 782 | |
| 783 | |
| 784 | uc32 RegExpParser::ParseClassCharacterEscape() { |
| 785 | DCHECK(current() == '\\'); |
| 786 | DCHECK(has_next() && !IsSpecialClassEscape(Next())); |
| 787 | Advance(); |
| 788 | switch (current()) { |
| 789 | case 'b': |
| 790 | Advance(); |
| 791 | return '\b'; |
| 792 | // ControlEscape :: one of |
| 793 | // f n r t v |
| 794 | case 'f': |
| 795 | Advance(); |
| 796 | return '\f'; |
| 797 | case 'n': |
| 798 | Advance(); |
| 799 | return '\n'; |
| 800 | case 'r': |
| 801 | Advance(); |
| 802 | return '\r'; |
| 803 | case 't': |
| 804 | Advance(); |
| 805 | return '\t'; |
| 806 | case 'v': |
| 807 | Advance(); |
| 808 | return '\v'; |
| 809 | case 'c': { |
| 810 | uc32 controlLetter = Next(); |
| 811 | uc32 letter = controlLetter & ~('A' ^ 'a'); |
| 812 | // For compatibility with JSC, inside a character class |
| 813 | // we also accept digits and underscore as control characters. |
| 814 | if ((controlLetter >= '0' && controlLetter <= '9') || |
| 815 | controlLetter == '_' || (letter >= 'A' && letter <= 'Z')) { |
| 816 | Advance(2); |
| 817 | // Control letters mapped to ASCII control characters in the range |
| 818 | // 0x00-0x1f. |
| 819 | return controlLetter & 0x1f; |
| 820 | } |
| 821 | // We match JSC in reading the backslash as a literal |
| 822 | // character instead of as starting an escape. |
| 823 | return '\\'; |
| 824 | } |
| 825 | case '0': |
| 826 | case '1': |
| 827 | case '2': |
| 828 | case '3': |
| 829 | case '4': |
| 830 | case '5': |
| 831 | case '6': |
| 832 | case '7': |
| 833 | // For compatibility, we interpret a decimal escape that isn't |
| 834 | // a back reference (and therefore either \0 or not valid according |
| 835 | // to the specification) as a 1..3 digit octal character code. |
| 836 | return ParseOctalLiteral(); |
| 837 | case 'x': { |
| 838 | Advance(); |
| 839 | uc32 value; |
| 840 | if (ParseHexEscape(2, &value)) { |
| 841 | return value; |
| 842 | } |
| 843 | if (!unicode_) { |
| 844 | // If \x is not followed by a two-digit hexadecimal, treat it |
| 845 | // as an identity escape. |
| 846 | return 'x'; |
| 847 | } |
| 848 | // If the 'u' flag is present, invalid escapes are not treated as |
| 849 | // identity escapes. |
| 850 | ReportError(CStrVector("Invalid escape")); |
| 851 | return 0; |
| 852 | } |
| 853 | case 'u': { |
| 854 | Advance(); |
| 855 | uc32 value; |
| 856 | if (ParseUnicodeEscape(&value)) { |
| 857 | return value; |
| 858 | } |
| 859 | if (!unicode_) { |
| 860 | return 'u'; |
| 861 | } |
| 862 | // If the 'u' flag is present, invalid escapes are not treated as |
| 863 | // identity escapes. |
| 864 | ReportError(CStrVector("Invalid unicode escape")); |
| 865 | return 0; |
| 866 | } |
| 867 | default: { |
| 868 | uc32 result = current(); |
| 869 | // If the 'u' flag is present, only syntax characters can be escaped, no |
| 870 | // other identity escapes are allowed. If the 'u' flag is not present, all |
| 871 | // identity escapes are allowed. |
| 872 | if (!unicode_ || IsSyntaxCharacter(result)) { |
| 873 | Advance(); |
| 874 | return result; |
| 875 | } |
| 876 | ReportError(CStrVector("Invalid escape")); |
| 877 | return 0; |
| 878 | } |
| 879 | } |
| 880 | return 0; |
| 881 | } |
| 882 | |
| 883 | |
| 884 | CharacterRange RegExpParser::ParseClassAtom(uc16* char_class) { |
| 885 | DCHECK_EQ(0, *char_class); |
| 886 | uc32 first = current(); |
| 887 | if (first == '\\') { |
| 888 | switch (Next()) { |
| 889 | case 'w': |
| 890 | case 'W': |
| 891 | case 'd': |
| 892 | case 'D': |
| 893 | case 's': |
| 894 | case 'S': { |
| 895 | *char_class = Next(); |
| 896 | Advance(2); |
| 897 | return CharacterRange::Singleton(0); // Return dummy value. |
| 898 | } |
| 899 | case kEndMarker: |
| 900 | return ReportError(CStrVector("\\ at end of pattern")); |
| 901 | default: |
| 902 | uc32 c = ParseClassCharacterEscape(CHECK_FAILED); |
| 903 | return CharacterRange::Singleton(c); |
| 904 | } |
| 905 | } else { |
| 906 | Advance(); |
| 907 | return CharacterRange::Singleton(first); |
| 908 | } |
| 909 | } |
| 910 | |
| 911 | |
| 912 | static const uc16 kNoCharClass = 0; |
| 913 | |
| 914 | // Adds range or pre-defined character class to character ranges. |
| 915 | // If char_class is not kInvalidClass, it's interpreted as a class |
| 916 | // escape (i.e., 's' means whitespace, from '\s'). |
| 917 | static inline void AddRangeOrEscape(ZoneList<CharacterRange>* ranges, |
| 918 | uc16 char_class, CharacterRange range, |
| 919 | Zone* zone) { |
| 920 | if (char_class != kNoCharClass) { |
| 921 | CharacterRange::AddClassEscape(char_class, ranges, zone); |
| 922 | } else { |
| 923 | ranges->Add(range, zone); |
| 924 | } |
| 925 | } |
| 926 | |
| 927 | |
| 928 | RegExpTree* RegExpParser::ParseCharacterClass() { |
| 929 | static const char* kUnterminated = "Unterminated character class"; |
| 930 | static const char* kRangeOutOfOrder = "Range out of order in character class"; |
| 931 | |
| 932 | DCHECK_EQ(current(), '['); |
| 933 | Advance(); |
| 934 | bool is_negated = false; |
| 935 | if (current() == '^') { |
| 936 | is_negated = true; |
| 937 | Advance(); |
| 938 | } |
| 939 | ZoneList<CharacterRange>* ranges = |
| 940 | new (zone()) ZoneList<CharacterRange>(2, zone()); |
| 941 | while (has_more() && current() != ']') { |
| 942 | uc16 char_class = kNoCharClass; |
| 943 | CharacterRange first = ParseClassAtom(&char_class CHECK_FAILED); |
| 944 | if (current() == '-') { |
| 945 | Advance(); |
| 946 | if (current() == kEndMarker) { |
| 947 | // If we reach the end we break out of the loop and let the |
| 948 | // following code report an error. |
| 949 | break; |
| 950 | } else if (current() == ']') { |
| 951 | AddRangeOrEscape(ranges, char_class, first, zone()); |
| 952 | ranges->Add(CharacterRange::Singleton('-'), zone()); |
| 953 | break; |
| 954 | } |
| 955 | uc16 char_class_2 = kNoCharClass; |
| 956 | CharacterRange next = ParseClassAtom(&char_class_2 CHECK_FAILED); |
| 957 | if (char_class != kNoCharClass || char_class_2 != kNoCharClass) { |
| 958 | // Either end is an escaped character class. Treat the '-' verbatim. |
| 959 | AddRangeOrEscape(ranges, char_class, first, zone()); |
| 960 | ranges->Add(CharacterRange::Singleton('-'), zone()); |
| 961 | AddRangeOrEscape(ranges, char_class_2, next, zone()); |
| 962 | continue; |
| 963 | } |
| 964 | if (first.from() > next.to()) { |
| 965 | return ReportError(CStrVector(kRangeOutOfOrder) CHECK_FAILED); |
| 966 | } |
| 967 | ranges->Add(CharacterRange::Range(first.from(), next.to()), zone()); |
| 968 | } else { |
| 969 | AddRangeOrEscape(ranges, char_class, first, zone()); |
| 970 | } |
| 971 | } |
| 972 | if (!has_more()) { |
| 973 | return ReportError(CStrVector(kUnterminated) CHECK_FAILED); |
| 974 | } |
| 975 | Advance(); |
| 976 | if (ranges->length() == 0) { |
| 977 | ranges->Add(CharacterRange::Everything(), zone()); |
| 978 | is_negated = !is_negated; |
| 979 | } |
| 980 | return new (zone()) RegExpCharacterClass(ranges, is_negated); |
| 981 | } |
| 982 | |
| 983 | |
| 984 | #undef CHECK_FAILED |
| 985 | |
| 986 | |
| 987 | bool RegExpParser::ParseRegExp(Isolate* isolate, Zone* zone, |
| 988 | FlatStringReader* input, bool multiline, |
| 989 | bool unicode, RegExpCompileData* result) { |
| 990 | DCHECK(result != NULL); |
| 991 | RegExpParser parser(input, &result->error, multiline, unicode, isolate, zone); |
| 992 | RegExpTree* tree = parser.ParsePattern(); |
| 993 | if (parser.failed()) { |
| 994 | DCHECK(tree == NULL); |
| 995 | DCHECK(!result->error.is_null()); |
| 996 | } else { |
| 997 | DCHECK(tree != NULL); |
| 998 | DCHECK(result->error.is_null()); |
| 999 | if (FLAG_trace_regexp_parser) { |
| 1000 | OFStream os(stdout); |
| 1001 | tree->Print(os, zone); |
| 1002 | os << "\n"; |
| 1003 | } |
| 1004 | result->tree = tree; |
| 1005 | int capture_count = parser.captures_started(); |
| 1006 | result->simple = tree->IsAtom() && parser.simple() && capture_count == 0; |
| 1007 | result->contains_anchor = parser.contains_anchor(); |
| 1008 | result->capture_count = capture_count; |
| 1009 | } |
| 1010 | return !parser.failed(); |
| 1011 | } |
| 1012 | |
| 1013 | |
| 1014 | RegExpBuilder::RegExpBuilder(Zone* zone) |
| 1015 | : zone_(zone), |
| 1016 | pending_empty_(false), |
| 1017 | characters_(NULL), |
| 1018 | terms_(), |
| 1019 | alternatives_() |
| 1020 | #ifdef DEBUG |
| 1021 | , |
| 1022 | last_added_(ADD_NONE) |
| 1023 | #endif |
| 1024 | { |
| 1025 | } |
| 1026 | |
| 1027 | |
| 1028 | void RegExpBuilder::FlushCharacters() { |
| 1029 | pending_empty_ = false; |
| 1030 | if (characters_ != NULL) { |
| 1031 | RegExpTree* atom = new (zone()) RegExpAtom(characters_->ToConstVector()); |
| 1032 | characters_ = NULL; |
| 1033 | text_.Add(atom, zone()); |
| 1034 | LAST(ADD_ATOM); |
| 1035 | } |
| 1036 | } |
| 1037 | |
| 1038 | |
| 1039 | void RegExpBuilder::FlushText() { |
| 1040 | FlushCharacters(); |
| 1041 | int num_text = text_.length(); |
| 1042 | if (num_text == 0) { |
| 1043 | return; |
| 1044 | } else if (num_text == 1) { |
| 1045 | terms_.Add(text_.last(), zone()); |
| 1046 | } else { |
| 1047 | RegExpText* text = new (zone()) RegExpText(zone()); |
| 1048 | for (int i = 0; i < num_text; i++) text_.Get(i)->AppendToText(text, zone()); |
| 1049 | terms_.Add(text, zone()); |
| 1050 | } |
| 1051 | text_.Clear(); |
| 1052 | } |
| 1053 | |
| 1054 | |
| 1055 | void RegExpBuilder::AddCharacter(uc16 c) { |
| 1056 | pending_empty_ = false; |
| 1057 | if (characters_ == NULL) { |
| 1058 | characters_ = new (zone()) ZoneList<uc16>(4, zone()); |
| 1059 | } |
| 1060 | characters_->Add(c, zone()); |
| 1061 | LAST(ADD_CHAR); |
| 1062 | } |
| 1063 | |
| 1064 | |
| 1065 | void RegExpBuilder::AddUnicodeCharacter(uc32 c) { |
| 1066 | if (c > unibrow::Utf16::kMaxNonSurrogateCharCode) { |
| 1067 | ZoneList<uc16> surrogate_pair(2, zone()); |
| 1068 | surrogate_pair.Add(unibrow::Utf16::LeadSurrogate(c), zone()); |
| 1069 | surrogate_pair.Add(unibrow::Utf16::TrailSurrogate(c), zone()); |
| 1070 | RegExpAtom* atom = new (zone()) RegExpAtom(surrogate_pair.ToConstVector()); |
| 1071 | AddAtom(atom); |
| 1072 | } else { |
| 1073 | AddCharacter(static_cast<uc16>(c)); |
| 1074 | } |
| 1075 | } |
| 1076 | |
| 1077 | |
| 1078 | void RegExpBuilder::AddEmpty() { pending_empty_ = true; } |
| 1079 | |
| 1080 | |
| 1081 | void RegExpBuilder::AddAtom(RegExpTree* term) { |
| 1082 | if (term->IsEmpty()) { |
| 1083 | AddEmpty(); |
| 1084 | return; |
| 1085 | } |
| 1086 | if (term->IsTextElement()) { |
| 1087 | FlushCharacters(); |
| 1088 | text_.Add(term, zone()); |
| 1089 | } else { |
| 1090 | FlushText(); |
| 1091 | terms_.Add(term, zone()); |
| 1092 | } |
| 1093 | LAST(ADD_ATOM); |
| 1094 | } |
| 1095 | |
| 1096 | |
| 1097 | void RegExpBuilder::AddAssertion(RegExpTree* assert) { |
| 1098 | FlushText(); |
| 1099 | terms_.Add(assert, zone()); |
| 1100 | LAST(ADD_ASSERT); |
| 1101 | } |
| 1102 | |
| 1103 | |
| 1104 | void RegExpBuilder::NewAlternative() { FlushTerms(); } |
| 1105 | |
| 1106 | |
| 1107 | void RegExpBuilder::FlushTerms() { |
| 1108 | FlushText(); |
| 1109 | int num_terms = terms_.length(); |
| 1110 | RegExpTree* alternative; |
| 1111 | if (num_terms == 0) { |
| 1112 | alternative = new (zone()) RegExpEmpty(); |
| 1113 | } else if (num_terms == 1) { |
| 1114 | alternative = terms_.last(); |
| 1115 | } else { |
| 1116 | alternative = new (zone()) RegExpAlternative(terms_.GetList(zone())); |
| 1117 | } |
| 1118 | alternatives_.Add(alternative, zone()); |
| 1119 | terms_.Clear(); |
| 1120 | LAST(ADD_NONE); |
| 1121 | } |
| 1122 | |
| 1123 | |
| 1124 | RegExpTree* RegExpBuilder::ToRegExp() { |
| 1125 | FlushTerms(); |
| 1126 | int num_alternatives = alternatives_.length(); |
| 1127 | if (num_alternatives == 0) return new (zone()) RegExpEmpty(); |
| 1128 | if (num_alternatives == 1) return alternatives_.last(); |
| 1129 | return new (zone()) RegExpDisjunction(alternatives_.GetList(zone())); |
| 1130 | } |
| 1131 | |
| 1132 | |
| 1133 | void RegExpBuilder::AddQuantifierToAtom( |
| 1134 | int min, int max, RegExpQuantifier::QuantifierType quantifier_type) { |
| 1135 | if (pending_empty_) { |
| 1136 | pending_empty_ = false; |
| 1137 | return; |
| 1138 | } |
| 1139 | RegExpTree* atom; |
| 1140 | if (characters_ != NULL) { |
| 1141 | DCHECK(last_added_ == ADD_CHAR); |
| 1142 | // Last atom was character. |
| 1143 | Vector<const uc16> char_vector = characters_->ToConstVector(); |
| 1144 | int num_chars = char_vector.length(); |
| 1145 | if (num_chars > 1) { |
| 1146 | Vector<const uc16> prefix = char_vector.SubVector(0, num_chars - 1); |
| 1147 | text_.Add(new (zone()) RegExpAtom(prefix), zone()); |
| 1148 | char_vector = char_vector.SubVector(num_chars - 1, num_chars); |
| 1149 | } |
| 1150 | characters_ = NULL; |
| 1151 | atom = new (zone()) RegExpAtom(char_vector); |
| 1152 | FlushText(); |
| 1153 | } else if (text_.length() > 0) { |
| 1154 | DCHECK(last_added_ == ADD_ATOM); |
| 1155 | atom = text_.RemoveLast(); |
| 1156 | FlushText(); |
| 1157 | } else if (terms_.length() > 0) { |
| 1158 | DCHECK(last_added_ == ADD_ATOM); |
| 1159 | atom = terms_.RemoveLast(); |
| 1160 | if (atom->max_match() == 0) { |
| 1161 | // Guaranteed to only match an empty string. |
| 1162 | LAST(ADD_TERM); |
| 1163 | if (min == 0) { |
| 1164 | return; |
| 1165 | } |
| 1166 | terms_.Add(atom, zone()); |
| 1167 | return; |
| 1168 | } |
| 1169 | } else { |
| 1170 | // Only call immediately after adding an atom or character! |
| 1171 | UNREACHABLE(); |
| 1172 | return; |
| 1173 | } |
| 1174 | terms_.Add(new (zone()) RegExpQuantifier(min, max, quantifier_type, atom), |
| 1175 | zone()); |
| 1176 | LAST(ADD_TERM); |
| 1177 | } |
| 1178 | |
| 1179 | } // namespace internal |
| 1180 | } // namespace v8 |