// Copyright 2011 the V8 project authors. All rights reserved. // Redistribution and use in source and binary forms, with or without // modification, are permitted provided that the following conditions are // met: // // * Redistributions of source code must retain the above copyright // notice, this list of conditions and the following disclaimer. // * Redistributions in binary form must reproduce the above // copyright notice, this list of conditions and the following // disclaimer in the documentation and/or other materials provided // with the distribution. // * Neither the name of Google Inc. nor the names of its // contributors may be used to endorse or promote products derived // from this software without specific prior written permission. // // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT // OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. // Features shared by parsing and pre-parsing scanners. #include "scanner.h" #include "../include/v8stdint.h" #include "char-predicates-inl.h" namespace v8 { namespace internal { // ---------------------------------------------------------------------------- // Scanner Scanner::Scanner(UnicodeCache* unicode_cache) : unicode_cache_(unicode_cache), octal_pos_(Location::invalid()), harmony_scoping_(false), harmony_modules_(false) { } void Scanner::Initialize(Utf16CharacterStream* source) { source_ = source; // Need to capture identifiers in order to recognize "get" and "set" // in object literals. Init(); // Skip initial whitespace allowing HTML comment ends just like // after a newline and scan first token. has_line_terminator_before_next_ = true; SkipWhiteSpace(); Scan(); } uc32 Scanner::ScanHexNumber(int expected_length) { ASSERT(expected_length <= 4); // prevent overflow uc32 digits[4] = { 0, 0, 0, 0 }; uc32 x = 0; for (int i = 0; i < expected_length; i++) { digits[i] = c0_; int d = HexValue(c0_); if (d < 0) { // According to ECMA-262, 3rd, 7.8.4, page 18, these hex escapes // should be illegal, but other JS VMs just return the // non-escaped version of the original character. // Push back digits that we have advanced past. for (int j = i-1; j >= 0; j--) { PushBack(digits[j]); } return -1; } x = x * 16 + d; Advance(); } return x; } // Ensure that tokens can be stored in a byte. STATIC_ASSERT(Token::NUM_TOKENS <= 0x100); // Table of one-character tokens, by character (0x00..0x7f only). static const byte one_char_tokens[] = { Token::ILLEGAL, Token::ILLEGAL, Token::ILLEGAL, Token::ILLEGAL, Token::ILLEGAL, Token::ILLEGAL, Token::ILLEGAL, Token::ILLEGAL, Token::ILLEGAL, Token::ILLEGAL, Token::ILLEGAL, Token::ILLEGAL, Token::ILLEGAL, Token::ILLEGAL, Token::ILLEGAL, Token::ILLEGAL, Token::ILLEGAL, Token::ILLEGAL, Token::ILLEGAL, Token::ILLEGAL, Token::ILLEGAL, Token::ILLEGAL, Token::ILLEGAL, Token::ILLEGAL, Token::ILLEGAL, Token::ILLEGAL, Token::ILLEGAL, Token::ILLEGAL, Token::ILLEGAL, Token::ILLEGAL, Token::ILLEGAL, Token::ILLEGAL, Token::ILLEGAL, Token::ILLEGAL, Token::ILLEGAL, Token::ILLEGAL, Token::ILLEGAL, Token::ILLEGAL, Token::ILLEGAL, Token::ILLEGAL, Token::LPAREN, // 0x28 Token::RPAREN, // 0x29 Token::ILLEGAL, Token::ILLEGAL, Token::COMMA, // 0x2c Token::ILLEGAL, Token::ILLEGAL, Token::ILLEGAL, Token::ILLEGAL, Token::ILLEGAL, Token::ILLEGAL, Token::ILLEGAL, Token::ILLEGAL, Token::ILLEGAL, Token::ILLEGAL, Token::ILLEGAL, Token::ILLEGAL, Token::ILLEGAL, Token::COLON, // 0x3a Token::SEMICOLON, // 0x3b Token::ILLEGAL, Token::ILLEGAL, Token::ILLEGAL, Token::CONDITIONAL, // 0x3f Token::ILLEGAL, Token::ILLEGAL, Token::ILLEGAL, Token::ILLEGAL, Token::ILLEGAL, Token::ILLEGAL, Token::ILLEGAL, Token::ILLEGAL, Token::ILLEGAL, Token::ILLEGAL, Token::ILLEGAL, Token::ILLEGAL, Token::ILLEGAL, Token::ILLEGAL, Token::ILLEGAL, Token::ILLEGAL, Token::ILLEGAL, Token::ILLEGAL, Token::ILLEGAL, Token::ILLEGAL, Token::ILLEGAL, Token::ILLEGAL, Token::ILLEGAL, Token::ILLEGAL, Token::ILLEGAL, Token::ILLEGAL, Token::ILLEGAL, Token::LBRACK, // 0x5b Token::ILLEGAL, Token::RBRACK, // 0x5d Token::ILLEGAL, Token::ILLEGAL, Token::ILLEGAL, Token::ILLEGAL, Token::ILLEGAL, Token::ILLEGAL, Token::ILLEGAL, Token::ILLEGAL, Token::ILLEGAL, Token::ILLEGAL, Token::ILLEGAL, Token::ILLEGAL, Token::ILLEGAL, Token::ILLEGAL, Token::ILLEGAL, Token::ILLEGAL, Token::ILLEGAL, Token::ILLEGAL, Token::ILLEGAL, Token::ILLEGAL, Token::ILLEGAL, Token::ILLEGAL, Token::ILLEGAL, Token::ILLEGAL, Token::ILLEGAL, Token::ILLEGAL, Token::ILLEGAL, Token::ILLEGAL, Token::ILLEGAL, Token::LBRACE, // 0x7b Token::ILLEGAL, Token::RBRACE, // 0x7d Token::BIT_NOT, // 0x7e Token::ILLEGAL }; Token::Value Scanner::Next() { current_ = next_; has_line_terminator_before_next_ = false; has_multiline_comment_before_next_ = false; if (static_cast(c0_) <= 0x7f) { Token::Value token = static_cast(one_char_tokens[c0_]); if (token != Token::ILLEGAL) { int pos = source_pos(); next_.token = token; next_.location.beg_pos = pos; next_.location.end_pos = pos + 1; Advance(); return current_.token; } } Scan(); return current_.token; } static inline bool IsByteOrderMark(uc32 c) { // The Unicode value U+FFFE is guaranteed never to be assigned as a // Unicode character; this implies that in a Unicode context the // 0xFF, 0xFE byte pattern can only be interpreted as the U+FEFF // character expressed in little-endian byte order (since it could // not be a U+FFFE character expressed in big-endian byte // order). Nevertheless, we check for it to be compatible with // Spidermonkey. return c == 0xFEFF || c == 0xFFFE; } bool Scanner::SkipWhiteSpace() { int start_position = source_pos(); while (true) { // We treat byte-order marks (BOMs) as whitespace for better // compatibility with Spidermonkey and other JavaScript engines. while (unicode_cache_->IsWhiteSpace(c0_) || IsByteOrderMark(c0_)) { // IsWhiteSpace() includes line terminators! if (unicode_cache_->IsLineTerminator(c0_)) { // Ignore line terminators, but remember them. This is necessary // for automatic semicolon insertion. has_line_terminator_before_next_ = true; } Advance(); } // If there is an HTML comment end '-->' at the beginning of a // line (with only whitespace in front of it), we treat the rest // of the line as a comment. This is in line with the way // SpiderMonkey handles it. if (c0_ == '-' && has_line_terminator_before_next_) { Advance(); if (c0_ == '-') { Advance(); if (c0_ == '>') { // Treat the rest of the line as a comment. SkipSingleLineComment(); // Continue skipping white space after the comment. continue; } PushBack('-'); // undo Advance() } PushBack('-'); // undo Advance() } // Return whether or not we skipped any characters. return source_pos() != start_position; } } Token::Value Scanner::SkipSingleLineComment() { Advance(); // The line terminator at the end of the line is not considered // to be part of the single-line comment; it is recognized // separately by the lexical grammar and becomes part of the // stream of input elements for the syntactic grammar (see // ECMA-262, section 7.4). while (c0_ >= 0 && !unicode_cache_->IsLineTerminator(c0_)) { Advance(); } return Token::WHITESPACE; } Token::Value Scanner::SkipMultiLineComment() { ASSERT(c0_ == '*'); Advance(); while (c0_ >= 0) { uc32 ch = c0_; Advance(); if (unicode_cache_->IsLineTerminator(ch)) { // Following ECMA-262, section 7.4, a comment containing // a newline will make the comment count as a line-terminator. has_multiline_comment_before_next_ = true; } // If we have reached the end of the multi-line comment, we // consume the '/' and insert a whitespace. This way all // multi-line comments are treated as whitespace. if (ch == '*' && c0_ == '/') { c0_ = ' '; return Token::WHITESPACE; } } // Unterminated multi-line comment. return Token::ILLEGAL; } Token::Value Scanner::ScanHtmlComment() { // Check for -= Advance(); if (c0_ == '-') { Advance(); if (c0_ == '>' && has_line_terminator_before_next_) { // For compatibility with SpiderMonkey, we skip lines that // start with an HTML comment end '-->'. token = SkipSingleLineComment(); } else { token = Token::DEC; } } else if (c0_ == '=') { token = Select(Token::ASSIGN_SUB); } else { token = Token::SUB; } break; case '*': // * *= token = Select('=', Token::ASSIGN_MUL, Token::MUL); break; case '%': // % %= token = Select('=', Token::ASSIGN_MOD, Token::MOD); break; case '/': // / // /* /= Advance(); if (c0_ == '/') { token = SkipSingleLineComment(); } else if (c0_ == '*') { token = SkipMultiLineComment(); } else if (c0_ == '=') { token = Select(Token::ASSIGN_DIV); } else { token = Token::DIV; } break; case '&': // & && &= Advance(); if (c0_ == '&') { token = Select(Token::AND); } else if (c0_ == '=') { token = Select(Token::ASSIGN_BIT_AND); } else { token = Token::BIT_AND; } break; case '|': // | || |= Advance(); if (c0_ == '|') { token = Select(Token::OR); } else if (c0_ == '=') { token = Select(Token::ASSIGN_BIT_OR); } else { token = Token::BIT_OR; } break; case '^': // ^ ^= token = Select('=', Token::ASSIGN_BIT_XOR, Token::BIT_XOR); break; case '.': // . Number Advance(); if (IsDecimalDigit(c0_)) { token = ScanNumber(true); } else { token = Token::PERIOD; } break; case ':': token = Select(Token::COLON); break; case ';': token = Select(Token::SEMICOLON); break; case ',': token = Select(Token::COMMA); break; case '(': token = Select(Token::LPAREN); break; case ')': token = Select(Token::RPAREN); break; case '[': token = Select(Token::LBRACK); break; case ']': token = Select(Token::RBRACK); break; case '{': token = Select(Token::LBRACE); break; case '}': token = Select(Token::RBRACE); break; case '?': token = Select(Token::CONDITIONAL); break; case '~': token = Select(Token::BIT_NOT); break; default: if (unicode_cache_->IsIdentifierStart(c0_)) { token = ScanIdentifierOrKeyword(); } else if (IsDecimalDigit(c0_)) { token = ScanNumber(false); } else if (SkipWhiteSpace()) { token = Token::WHITESPACE; } else if (c0_ < 0) { token = Token::EOS; } else { token = Select(Token::ILLEGAL); } break; } // Continue scanning for tokens as long as we're just skipping // whitespace. } while (token == Token::WHITESPACE); next_.location.end_pos = source_pos(); next_.token = token; } void Scanner::SeekForward(int pos) { // After this call, we will have the token at the given position as // the "next" token. The "current" token will be invalid. if (pos == next_.location.beg_pos) return; int current_pos = source_pos(); ASSERT_EQ(next_.location.end_pos, current_pos); // Positions inside the lookahead token aren't supported. ASSERT(pos >= current_pos); if (pos != current_pos) { source_->SeekForward(pos - source_->pos()); Advance(); // This function is only called to seek to the location // of the end of a function (at the "}" token). It doesn't matter // whether there was a line terminator in the part we skip. has_line_terminator_before_next_ = false; has_multiline_comment_before_next_ = false; } Scan(); } bool Scanner::ScanEscape() { uc32 c = c0_; Advance(); // Skip escaped newlines. if (unicode_cache_->IsLineTerminator(c)) { // Allow CR+LF newlines in multiline string literals. if (IsCarriageReturn(c) && IsLineFeed(c0_)) Advance(); // Allow LF+CR newlines in multiline string literals. if (IsLineFeed(c) && IsCarriageReturn(c0_)) Advance(); return true; } switch (c) { case '\'': // fall through case '"' : // fall through case '\\': break; case 'b' : c = '\b'; break; case 'f' : c = '\f'; break; case 'n' : c = '\n'; break; case 'r' : c = '\r'; break; case 't' : c = '\t'; break; case 'u' : { c = ScanHexNumber(4); if (c < 0) return false; break; } case 'v' : c = '\v'; break; case 'x' : { c = ScanHexNumber(2); if (c < 0) return false; break; } case '0' : // fall through case '1' : // fall through case '2' : // fall through case '3' : // fall through case '4' : // fall through case '5' : // fall through case '6' : // fall through case '7' : c = ScanOctalEscape(c, 2); break; } // According to ECMA-262, section 7.8.4, characters not covered by the // above cases should be illegal, but they are commonly handled as // non-escaped characters by JS VMs. AddLiteralChar(c); return true; } // Octal escapes of the forms '\0xx' and '\xxx' are not a part of // ECMA-262. Other JS VMs support them. uc32 Scanner::ScanOctalEscape(uc32 c, int length) { uc32 x = c - '0'; int i = 0; for (; i < length; i++) { int d = c0_ - '0'; if (d < 0 || d > 7) break; int nx = x * 8 + d; if (nx >= 256) break; x = nx; Advance(); } // Anything except '\0' is an octal escape sequence, illegal in strict mode. // Remember the position of octal escape sequences so that an error // can be reported later (in strict mode). // We don't report the error immediately, because the octal escape can // occur before the "use strict" directive. if (c != '0' || i > 0) { octal_pos_ = Location(source_pos() - i - 1, source_pos() - 1); } return x; } Token::Value Scanner::ScanString() { uc32 quote = c0_; Advance(); // consume quote LiteralScope literal(this); while (c0_ != quote && c0_ >= 0 && !unicode_cache_->IsLineTerminator(c0_)) { uc32 c = c0_; Advance(); if (c == '\\') { if (c0_ < 0 || !ScanEscape()) return Token::ILLEGAL; } else { AddLiteralChar(c); } } if (c0_ != quote) return Token::ILLEGAL; literal.Complete(); Advance(); // consume quote return Token::STRING; } void Scanner::ScanDecimalDigits() { while (IsDecimalDigit(c0_)) AddLiteralCharAdvance(); } Token::Value Scanner::ScanNumber(bool seen_period) { ASSERT(IsDecimalDigit(c0_)); // the first digit of the number or the fraction enum { DECIMAL, HEX, OCTAL } kind = DECIMAL; LiteralScope literal(this); if (seen_period) { // we have already seen a decimal point of the float AddLiteralChar('.'); ScanDecimalDigits(); // we know we have at least one digit } else { // if the first character is '0' we must check for octals and hex if (c0_ == '0') { int start_pos = source_pos(); // For reporting octal positions. AddLiteralCharAdvance(); // either 0, 0exxx, 0Exxx, 0.xxx, an octal number, or a hex number if (c0_ == 'x' || c0_ == 'X') { // hex number kind = HEX; AddLiteralCharAdvance(); if (!IsHexDigit(c0_)) { // we must have at least one hex digit after 'x'/'X' return Token::ILLEGAL; } while (IsHexDigit(c0_)) { AddLiteralCharAdvance(); } } else if ('0' <= c0_ && c0_ <= '7') { // (possible) octal number kind = OCTAL; while (true) { if (c0_ == '8' || c0_ == '9') { kind = DECIMAL; break; } if (c0_ < '0' || '7' < c0_) { // Octal literal finished. octal_pos_ = Location(start_pos, source_pos()); break; } AddLiteralCharAdvance(); } } } // Parse decimal digits and allow trailing fractional part. if (kind == DECIMAL) { ScanDecimalDigits(); // optional if (c0_ == '.') { AddLiteralCharAdvance(); ScanDecimalDigits(); // optional } } } // scan exponent, if any if (c0_ == 'e' || c0_ == 'E') { ASSERT(kind != HEX); // 'e'/'E' must be scanned as part of the hex number if (kind == OCTAL) return Token::ILLEGAL; // no exponent for octals allowed // scan exponent AddLiteralCharAdvance(); if (c0_ == '+' || c0_ == '-') AddLiteralCharAdvance(); if (!IsDecimalDigit(c0_)) { // we must have at least one decimal digit after 'e'/'E' return Token::ILLEGAL; } ScanDecimalDigits(); } // The source character immediately following a numeric literal must // not be an identifier start or a decimal digit; see ECMA-262 // section 7.8.3, page 17 (note that we read only one decimal digit // if the value is 0). if (IsDecimalDigit(c0_) || unicode_cache_->IsIdentifierStart(c0_)) return Token::ILLEGAL; literal.Complete(); return Token::NUMBER; } uc32 Scanner::ScanIdentifierUnicodeEscape() { Advance(); if (c0_ != 'u') return -1; Advance(); uc32 result = ScanHexNumber(4); if (result < 0) PushBack('u'); return result; } // ---------------------------------------------------------------------------- // Keyword Matcher #define KEYWORDS(KEYWORD_GROUP, KEYWORD) \ KEYWORD_GROUP('b') \ KEYWORD("break", Token::BREAK) \ KEYWORD_GROUP('c') \ KEYWORD("case", Token::CASE) \ KEYWORD("catch", Token::CATCH) \ KEYWORD("class", Token::FUTURE_RESERVED_WORD) \ KEYWORD("const", Token::CONST) \ KEYWORD("continue", Token::CONTINUE) \ KEYWORD_GROUP('d') \ KEYWORD("debugger", Token::DEBUGGER) \ KEYWORD("default", Token::DEFAULT) \ KEYWORD("delete", Token::DELETE) \ KEYWORD("do", Token::DO) \ KEYWORD_GROUP('e') \ KEYWORD("else", Token::ELSE) \ KEYWORD("enum", Token::FUTURE_RESERVED_WORD) \ KEYWORD("export", harmony_modules \ ? Token::EXPORT : Token::FUTURE_RESERVED_WORD) \ KEYWORD("extends", Token::FUTURE_RESERVED_WORD) \ KEYWORD_GROUP('f') \ KEYWORD("false", Token::FALSE_LITERAL) \ KEYWORD("finally", Token::FINALLY) \ KEYWORD("for", Token::FOR) \ KEYWORD("function", Token::FUNCTION) \ KEYWORD_GROUP('i') \ KEYWORD("if", Token::IF) \ KEYWORD("implements", Token::FUTURE_STRICT_RESERVED_WORD) \ KEYWORD("import", harmony_modules \ ? Token::IMPORT : Token::FUTURE_RESERVED_WORD) \ KEYWORD("in", Token::IN) \ KEYWORD("instanceof", Token::INSTANCEOF) \ KEYWORD("interface", Token::FUTURE_STRICT_RESERVED_WORD) \ KEYWORD_GROUP('l') \ KEYWORD("let", harmony_scoping \ ? Token::LET : Token::FUTURE_STRICT_RESERVED_WORD) \ KEYWORD_GROUP('n') \ KEYWORD("new", Token::NEW) \ KEYWORD("null", Token::NULL_LITERAL) \ KEYWORD_GROUP('p') \ KEYWORD("package", Token::FUTURE_STRICT_RESERVED_WORD) \ KEYWORD("private", Token::FUTURE_STRICT_RESERVED_WORD) \ KEYWORD("protected", Token::FUTURE_STRICT_RESERVED_WORD) \ KEYWORD("public", Token::FUTURE_STRICT_RESERVED_WORD) \ KEYWORD_GROUP('r') \ KEYWORD("return", Token::RETURN) \ KEYWORD_GROUP('s') \ KEYWORD("static", Token::FUTURE_STRICT_RESERVED_WORD) \ KEYWORD("super", Token::FUTURE_RESERVED_WORD) \ KEYWORD("switch", Token::SWITCH) \ KEYWORD_GROUP('t') \ KEYWORD("this", Token::THIS) \ KEYWORD("throw", Token::THROW) \ KEYWORD("true", Token::TRUE_LITERAL) \ KEYWORD("try", Token::TRY) \ KEYWORD("typeof", Token::TYPEOF) \ KEYWORD_GROUP('v') \ KEYWORD("var", Token::VAR) \ KEYWORD("void", Token::VOID) \ KEYWORD_GROUP('w') \ KEYWORD("while", Token::WHILE) \ KEYWORD("with", Token::WITH) \ KEYWORD_GROUP('y') \ KEYWORD("yield", Token::FUTURE_STRICT_RESERVED_WORD) static Token::Value KeywordOrIdentifierToken(const char* input, int input_length, bool harmony_scoping, bool harmony_modules) { ASSERT(input_length >= 1); const int kMinLength = 2; const int kMaxLength = 10; if (input_length < kMinLength || input_length > kMaxLength) { return Token::IDENTIFIER; } switch (input[0]) { default: #define KEYWORD_GROUP_CASE(ch) \ break; \ case ch: #define KEYWORD(keyword, token) \ { \ /* 'keyword' is a char array, so sizeof(keyword) is */ \ /* strlen(keyword) plus 1 for the NUL char. */ \ const int keyword_length = sizeof(keyword) - 1; \ STATIC_ASSERT(keyword_length >= kMinLength); \ STATIC_ASSERT(keyword_length <= kMaxLength); \ if (input_length == keyword_length && \ input[1] == keyword[1] && \ (keyword_length <= 2 || input[2] == keyword[2]) && \ (keyword_length <= 3 || input[3] == keyword[3]) && \ (keyword_length <= 4 || input[4] == keyword[4]) && \ (keyword_length <= 5 || input[5] == keyword[5]) && \ (keyword_length <= 6 || input[6] == keyword[6]) && \ (keyword_length <= 7 || input[7] == keyword[7]) && \ (keyword_length <= 8 || input[8] == keyword[8]) && \ (keyword_length <= 9 || input[9] == keyword[9])) { \ return token; \ } \ } KEYWORDS(KEYWORD_GROUP_CASE, KEYWORD) } return Token::IDENTIFIER; } Token::Value Scanner::ScanIdentifierOrKeyword() { ASSERT(unicode_cache_->IsIdentifierStart(c0_)); LiteralScope literal(this); // Scan identifier start character. if (c0_ == '\\') { uc32 c = ScanIdentifierUnicodeEscape(); // Only allow legal identifier start characters. if (c < 0 || c == '\\' || // No recursive escapes. !unicode_cache_->IsIdentifierStart(c)) { return Token::ILLEGAL; } AddLiteralChar(c); return ScanIdentifierSuffix(&literal); } uc32 first_char = c0_; Advance(); AddLiteralChar(first_char); // Scan the rest of the identifier characters. while (unicode_cache_->IsIdentifierPart(c0_)) { if (c0_ != '\\') { uc32 next_char = c0_; Advance(); AddLiteralChar(next_char); continue; } // Fallthrough if no longer able to complete keyword. return ScanIdentifierSuffix(&literal); } literal.Complete(); if (next_.literal_chars->is_ascii()) { Vector chars = next_.literal_chars->ascii_literal(); return KeywordOrIdentifierToken(chars.start(), chars.length(), harmony_scoping_, harmony_modules_); } return Token::IDENTIFIER; } Token::Value Scanner::ScanIdentifierSuffix(LiteralScope* literal) { // Scan the rest of the identifier characters. while (unicode_cache_->IsIdentifierPart(c0_)) { if (c0_ == '\\') { uc32 c = ScanIdentifierUnicodeEscape(); // Only allow legal identifier part characters. if (c < 0 || c == '\\' || !unicode_cache_->IsIdentifierPart(c)) { return Token::ILLEGAL; } AddLiteralChar(c); } else { AddLiteralChar(c0_); Advance(); } } literal->Complete(); return Token::IDENTIFIER; } bool Scanner::ScanRegExpPattern(bool seen_equal) { // Scan: ('/' | '/=') RegularExpressionBody '/' RegularExpressionFlags bool in_character_class = false; // Previous token is either '/' or '/=', in the second case, the // pattern starts at =. next_.location.beg_pos = source_pos() - (seen_equal ? 2 : 1); next_.location.end_pos = source_pos() - (seen_equal ? 1 : 0); // Scan regular expression body: According to ECMA-262, 3rd, 7.8.5, // the scanner should pass uninterpreted bodies to the RegExp // constructor. LiteralScope literal(this); if (seen_equal) { AddLiteralChar('='); } while (c0_ != '/' || in_character_class) { if (unicode_cache_->IsLineTerminator(c0_) || c0_ < 0) return false; if (c0_ == '\\') { // Escape sequence. AddLiteralCharAdvance(); if (unicode_cache_->IsLineTerminator(c0_) || c0_ < 0) return false; AddLiteralCharAdvance(); // If the escape allows more characters, i.e., \x??, \u????, or \c?, // only "safe" characters are allowed (letters, digits, underscore), // otherwise the escape isn't valid and the invalid character has // its normal meaning. I.e., we can just continue scanning without // worrying whether the following characters are part of the escape // or not, since any '/', '\\' or '[' is guaranteed to not be part // of the escape sequence. // TODO(896): At some point, parse RegExps more throughly to capture // octal esacpes in strict mode. } else { // Unescaped character. if (c0_ == '[') in_character_class = true; if (c0_ == ']') in_character_class = false; AddLiteralCharAdvance(); } } Advance(); // consume '/' literal.Complete(); return true; } bool Scanner::ScanLiteralUnicodeEscape() { ASSERT(c0_ == '\\'); uc32 chars_read[6] = {'\\', 'u', 0, 0, 0, 0}; Advance(); int i = 1; if (c0_ == 'u') { i++; while (i < 6) { Advance(); if (!IsHexDigit(c0_)) break; chars_read[i] = c0_; i++; } } if (i < 6) { // Incomplete escape. Undo all advances and return false. while (i > 0) { i--; PushBack(chars_read[i]); } return false; } // Complete escape. Add all chars to current literal buffer. for (int i = 0; i < 6; i++) { AddLiteralChar(chars_read[i]); } return true; } bool Scanner::ScanRegExpFlags() { // Scan regular expression flags. LiteralScope literal(this); while (unicode_cache_->IsIdentifierPart(c0_)) { if (c0_ != '\\') { AddLiteralCharAdvance(); } else { if (!ScanLiteralUnicodeEscape()) { break; } Advance(); } } literal.Complete(); next_.location.end_pos = source_pos() - 1; return true; } } } // namespace v8::internal