Mozilla/mozilla/js2/src/lexer.cpp
gerv%gerv.net 76529f3fd6 Bug 236613: change to MPL/LGPL/GPL tri-license.
git-svn-id: svn://10.0.0.236/trunk@185990 18797224-902f-48f8-a5cc-f745e15eee43
2005-12-13 13:25:40 +00:00

771 lines
25 KiB
C++

/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*-
*
* ***** BEGIN LICENSE BLOCK *****
* Version: MPL 1.1/GPL 2.0/LGPL 2.1
*
* The contents of this file are subject to the Mozilla Public License Version
* 1.1 (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
* http://www.mozilla.org/MPL/
*
* Software distributed under the License is distributed on an "AS IS" basis,
* WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
* for the specific language governing rights and limitations under the
* License.
*
* The Original Code is the JavaScript 2 Prototype.
*
* The Initial Developer of the Original Code is
* Netscape Communications Corporation.
* Portions created by the Initial Developer are Copyright (C) 1998
* the Initial Developer. All Rights Reserved.
*
* Contributor(s):
*
* Alternatively, the contents of this file may be used under the terms of
* either the GNU General Public License Version 2 or later (the "GPL"), or
* the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
* in which case the provisions of the GPL or the LGPL are applicable instead
* of those above. If you wish to allow use of your version of this file only
* under the terms of either the GPL or the LGPL, and not to allow others to
* use your version of this file under the terms of the MPL, indicate your
* decision by deleting the provisions above and replace them with the notice
* and other provisions required by the GPL or the LGPL. If you do not delete
* the provisions above, a recipient may use your version of this file under
* the terms of any one of the MPL, the GPL or the LGPL.
*
* ***** END LICENSE BLOCK ***** */
#include <vector>
#include "systemtypes.h"
#include "js2value.h"
#include "numerics.h"
#include "lexer.h"
namespace JS = JavaScript;
// Create a new Lexer for lexing the provided source code. The Lexer will
// intern identifiers, keywords, and regular expressions in the designated
// world.
JS::Lexer::Lexer(World &world, const String &source, const String &sourceLocation, uint32 initialLineNum):
world(world), reader(source, sourceLocation, initialLineNum)
{
nextToken = tokens;
nTokensFwd = 0;
#ifdef DEBUG
nTokensBack = 0;
#endif
lexingUnit = false;
}
// Skip past the next token, which must have been either peeked or read and then unread.
// skip is faster than get but must not be called if the next token has not been seen yet.
void JS::Lexer::skip()
{
ASSERT(nTokensFwd);
if (++nextToken == tokens + tokenBufferSize)
nextToken = tokens;
--nTokensFwd;
DEBUG_ONLY(++nTokensBack);
}
// Get and return the next token. The token remains valid until the next
// call to this Lexer. If the Reader reached the end of file, return a
// Token whose Kind is end. The caller may alter the value of this Token
// (in particular, take control over the auto_ptr's data), but if it does so,
// the caller is not allowed to unget this Token.
//
// If preferRegExp is true, a / will be preferentially interpreted as
// starting a regular expression; otherwise, a / will be preferentially
// interpreted as division or /=.
const JS::Token &JS::Lexer::get(bool preferRegExp)
{
const Token &t = peek(preferRegExp);
if (++nextToken == tokens + tokenBufferSize)
nextToken = tokens;
--nTokensFwd;
DEBUG_ONLY(++nTokensBack);
return t;
}
// Peek at the next token using the given preferRegExp setting. If that
// token's kind matches the given kind, consume that token and return it.
// Otherwise, do not consume that token and return nil.
const JS::Token *JS::Lexer::eat(bool preferRegExp, Token::Kind kind)
{
const Token &t = peek(preferRegExp);
if (t.kind != kind)
return 0;
if (++nextToken == tokens + tokenBufferSize)
nextToken = tokens;
--nTokensFwd;
DEBUG_ONLY(++nTokensBack);
return &t;
}
// Return the next token without consuming it.
//
// If preferRegExp is true, a / will be preferentially interpreted as
// starting a regular expression; otherwise, a / will be preferentially
// interpreted as division or /=. A subsequent call to peek or get will
// return the same token; that call must be presented with the same value
// for preferRegExp.
const JS::Token &JS::Lexer::peek(bool preferRegExp)
{
// Use an already looked-up token if there is one.
if (nTokensFwd) {
ASSERT(savedPreferRegExp[nextToken - tokens] == preferRegExp);
} else {
lexToken(preferRegExp);
nTokensFwd = 1;
#ifdef DEBUG
savedPreferRegExp[nextToken - tokens] = preferRegExp;
if (nTokensBack == tokenLookahead) {
nTokensBack = tokenLookahead-1;
if (tokenGuard)
(nextToken >= tokens+tokenLookahead ?
nextToken-tokenLookahead :
nextToken+tokenBufferSize-tokenLookahead)->valid = false;
}
#endif
}
return *nextToken;
}
#ifdef DEBUG
// Change the setting of preferRegExp for an already peeked token.
// The token must not be one for which that setting mattered.
//
// THIS IS A DANGEROUS FUNCTION!
// Use it only if you can be prove that the already peeked token does not
// start with a slash.
void JS::Lexer::redesignate(bool preferRegExp)
{
if (nTokensFwd) {
ASSERT(savedPreferRegExp[nextToken - tokens] != preferRegExp);
ASSERT(!(nextToken->hasKind(Token::regExp) ||
nextToken->hasKind(Token::divide) ||
nextToken->hasKind(Token::divideEquals)));
savedPreferRegExp[nextToken - tokens] = preferRegExp;
}
}
#endif
// Unread the last token. This call may be called to unread at most
// tokenBufferSize tokens at a time (where a peek also counts as temporarily
// reading and unreading one token). When a token that has been unread is
// peeked or read again, the same value must be passed in preferRegExp as for
// the first time that token was read or peeked.
void JS::Lexer::unget()
{
ASSERT(nTokensBack--);
nTokensFwd++;
if (nextToken == tokens)
nextToken = tokens + tokenBufferSize;
--nextToken;
}
// Report a syntax error at the backUp-th last character read by the Reader.
// In other words, if backUp is 0, the error is at the next character to be
// read by the Reader; if backUp is 1, the error is at the last character
// read by the Reader, and so forth.
void JS::Lexer::syntaxError(const char *message, uint backUp)
{
reader.unget(backUp);
reader.error(Exception::syntaxError, widenCString(message), reader.getPos());
}
// Get the next character from the reader, skipping any Unicode format-control
// (Cf) characters.
inline char16 JS::Lexer::getChar()
{
char16 ch = reader.get();
if (char16Value(ch) >= firstFormatChar)
ch = internalGetChar(ch);
return ch;
}
// Helper for getChar()
char16 JS::Lexer::internalGetChar(char16 ch)
{
while (isFormat(ch))
ch = reader.get();
return ch;
}
// Peek the next character from the reader, skipping any Unicode
// format-control (Cf) characters, which are read and discarded.
inline char16 JS::Lexer::peekChar()
{
char16 ch = reader.peek();
if (char16Value(ch) >= firstFormatChar)
ch = internalPeekChar(ch);
return ch;
}
// Helper for peekChar()
char16 JS::Lexer::internalPeekChar(char16 ch)
{
while (isFormat(ch)) {
reader.get();
ch = reader.peek();
}
return ch;
}
// Peek the next character from the reader, skipping any Unicode
// format-control (Cf) characters, which are read and discarded. If the
// peeked character matches ch, read that character and return true;
// otherwise return false. ch must not be null.
bool JS::Lexer::testChar(char16 ch)
{
ASSERT(ch); // If ch were null, it could match the eof null.
char16 ch2 = peekChar();
if (ch == ch2) {
reader.get();
return true;
}
return false;
}
// A backslash has been read. Read the rest of the escape code.
// Return the interpreted escaped character. Throw an exception if the
// escape is not valid. If unicodeOnly is true, allow only \uxxxx escapes.
char16 JS::Lexer::lexEscape(bool unicodeOnly)
{
char16 ch = getChar();
int nDigits;
if (!unicodeOnly || ch == 'u')
switch (ch) {
case '0':
// Make sure that the next character isn't a digit.
ch = peekChar();
if (!isASCIIDecimalDigit(ch))
return 0x00;
/*
// Point to the next character in the error message
getChar();
break;
*/
/* E3 compatibility, parse the sequence as octal */
{
uint32 n = 0;
while (isASCIIDecimalDigit(ch)) {
ch = getChar();
n = (n << 3) | (ch - '0');
ch = peekChar();
}
return static_cast<char16>(n);
}
case 'b':
return 0x08;
case 'f':
return 0x0C;
case 'n':
return 0x0A;
case 'r':
return 0x0D;
case 't':
return 0x09;
case 'v':
return 0x0B;
case 'x':
nDigits = 2;
goto lexHex;
case 'u':
nDigits = 4;
lexHex:
{
uint32 n = 0;
while (nDigits--) {
ch = getChar();
uint digit;
if (!isASCIIHexDigit(ch, digit)) {
/* E3 compatibility, back off */
// goto error;
do {
reader.unget();
ch = peekChar();
} while (ch != '\\');
return getChar();
}
n = (n << 4) | digit;
}
return static_cast<char16>(n);
}
default:
/*
if (!reader.getEof(ch)) {
CharInfo chi(ch);
if (!isAlphanumeric(chi) && !isLineBreak(chi))
return ch;
}
*/
return ch;
}
// error:
syntaxError("Bad escape code");
return 0;
}
// Read an identifier into s. The initial value of s is ignored and cleared.
// Return true if an escape code has been encountered.
// If allowLeadingDigit is true, allow the first character of s to be a digit,
// just like any continuing identifier character.
bool JS::Lexer::lexIdentifier(String &s, bool allowLeadingDigit)
{
reader.beginRecording(s);
bool hasEscape = false;
while (true) {
char16 ch = getChar();
char16 ch2 = ch;
if (ch == '\\') {
ch2 = lexEscape(true);
hasEscape = true;
}
CharInfo chi2(ch2);
if (!(allowLeadingDigit ? isIdContinuing(chi2) :
isIdLeading(chi2))) {
if (ch == '\\')
syntaxError("Identifier escape expands into non-identifier character");
else
reader.unget();
break;
}
reader.recordChar(ch2);
allowLeadingDigit = true;
}
reader.endRecording();
return hasEscape;
}
// Read a numeric literal into nextToken->chars and nextToken->value.
// Return true if the numeric literal is followed by a unit, but don't read
// the unit yet.
bool JS::Lexer::lexNumeral()
{
int hasDecimalPoint = 0;
bool hexadecimal = false;
bool octal = false;
String &s = nextToken->chars;
uint digit;
reader.beginRecording(s);
char16 ch = getChar();
if (ch == '0') {
reader.recordChar('0');
ch = getChar();
if ((ch&~0x20) == 'X') {
size_t pos = reader.getPos();
char16 ch2 = getChar();
if (isASCIIHexDigit(ch2, digit)) {
hexadecimal = true;
reader.recordChar(ch);
do {
reader.recordChar(ch2);
ch2 = getChar();
} while (isASCIIHexDigit(ch2, digit));
ch = ch2;
} else
reader.setPos(pos);
goto done;
} else if (isASCIIOctalDigit(ch)) {
// Backward compatible hack, support octal for SpiderMonkey's sake
octal = true;
while (isASCIIOctalDigit(ch)) {
reader.recordChar(ch);
ch = getChar();
}
goto done;
// syntaxError("Numeric constant syntax error");
}
}
while (isASCIIDecimalDigit(ch) || ch == '.' && !hasDecimalPoint++) {
reader.recordChar(ch);
ch = getChar();
}
if ((ch&~0x20) == 'E') {
size_t pos = reader.getPos();
char16 ch2 = getChar();
char16 sign = 0;
if (ch2 == '+' || ch2 == '-') {
sign = ch2;
ch2 = getChar();
}
if (isASCIIDecimalDigit(ch2)) {
reader.recordChar(ch);
if (sign)
reader.recordChar(sign);
do {
reader.recordChar(ch2);
ch2 = getChar();
} while (isASCIIDecimalDigit(ch2));
ch = ch2;
} else
reader.setPos(pos);
}
done:
// At this point the reader is just past the character ch, which
// is the first non-formatting character that is not part of the
// number.
reader.endRecording();
const char16 *sBegin = s.data();
const char16 *sEnd = sBegin + s.size();
const char16 *numEnd;
nextToken->value = hexadecimal ?
stringToInteger(sBegin, sEnd, numEnd, 16)
: octal ?
stringToInteger(sBegin, sEnd, numEnd, 8)
: stringToDouble(sBegin, sEnd, numEnd);
ASSERT(numEnd == sEnd);
reader.unget();
ASSERT(ch == reader.peek());
return isIdContinuing(ch) || ch == '\\';
}
// Read a string literal into s. The initial value of s is ignored and
// cleared. The opening quote has already been read into separator.
void JS::Lexer::lexString(String &s, char16 separator)
{
char16 ch;
reader.beginRecording(s);
while ((ch = reader.get()) != separator) {
CharInfo chi(ch);
if (!isFormat(chi)) {
if (ch == '\\')
ch = lexEscape(false);
else if (reader.getEof(ch) || isLineBreak(chi))
syntaxError("Unterminated string literal");
reader.recordChar(ch);
}
}
reader.endRecording();
}
// Read a regular expression literal. Store the regular expression in
// nextToken->id and the flags in nextToken->chars.
// The opening slash has already been read.
void JS::Lexer::lexRegExp()
{
String s;
char16 prevCh = 0;
reader.beginRecording(s);
while (true) {
char16 ch = getChar();
CharInfo chi(ch);
if (reader.getEof(ch) || isLineBreak(chi))
syntaxError("Unterminated regular expression literal");
if (prevCh == '\\') {
reader.recordChar(ch);
// Ignore slashes and backslashes immediately after a backslash
prevCh = 0;
} else if (ch != '/') {
reader.recordChar(ch);
prevCh = ch;
} else
break;
}
reader.endRecording();
nextToken->id = &world.identifiers[s];
lexIdentifier(nextToken->chars, true);
}
// Read a token from the Reader and store it at *nextToken.
// If the Reader reached the end of file, store a Token whose Kind is end.
void JS::Lexer::lexToken(bool preferRegExp)
{
Token &t = *nextToken;
t.lineBreak = false;
t.id = 0;
// Don't really need to waste time clearing this string here
//clear(t.chars);
Token::Kind kind;
if (lexingUnit) {
if (reader.peek() == '_')
syntaxError("Unit suffix may not begin with an underscore", 0);
lexIdentifier(t.chars, false);
ASSERT(t.chars.size());
kind = Token::unit; // unit
lexingUnit = false;
} else {
next:
char16 ch = reader.get();
if (reader.getEof(ch)) {
endOfInput:
t.pos = reader.getPos() - 1;
kind = Token::end;
} else {
char16 ch2;
CharInfo chi(ch);
switch (cGroup(chi)) {
case CharInfo::FormatGroup:
case CharInfo::WhiteGroup:
goto next;
case CharInfo::IdGroup:
t.pos = reader.getPos() - 1;
readIdentifier:
{
reader.unget();
String s;
bool hasEscape = lexIdentifier(s, false);
t.id = &world.identifiers[s];
kind = hasEscape ? Token::identifier : t.id->tokenKind;
}
break;
case CharInfo::NonIdGroup:
case CharInfo::IdContinueGroup:
t.pos = reader.getPos() - 1;
switch (ch) {
case '(':
kind = Token::openParenthesis; // (
break;
case ')':
kind = Token::closeParenthesis; // )
break;
case '[':
kind = Token::openBracket; // [
break;
case ']':
kind = Token::closeBracket; // ]
break;
case '{':
kind = Token::openBrace; // {
break;
case '}':
kind = Token::closeBrace; // }
break;
case ',':
kind = Token::comma; // ,
break;
case ';':
kind = Token::semicolon; // ;
break;
case '.':
kind = Token::dot; // .
ch2 = getChar();
if (isASCIIDecimalDigit(ch2)) {
reader.setPos(t.pos);
goto number; // decimal point
} else if (ch2 == '.') {
kind = Token::doubleDot; // ..
if (testChar('.'))
kind = Token::tripleDot;// ...
} else
reader.unget();
break;
case ':':
kind = Token::colon; // :
if (testChar(':'))
kind = Token::doubleColon; // ::
break;
case '#':
kind = Token::pound; // #
break;
case '@':
kind = Token::at; // @
break;
case '?':
kind = Token::question; // ?
break;
case '~':
kind = Token::complement; // ~
break;
case '!':
kind = Token::logicalNot; // !
if (testChar('=')) {
kind = Token::notEqual; // !=
if (testChar('='))
kind = Token::notIdentical; // !==
}
break;
case '*':
kind = Token::times; // * *=
tryAssignment:
if (testChar('='))
kind = Token::Kind(kind + Token::timesEquals - Token::times);
break;
case '/':
kind = Token::divide; // /
ch = getChar();
if (ch == '/') { // // comment
do {
ch = reader.get();
if (reader.getEof(ch))
goto endOfInput;
} while (!isLineBreak(ch));
goto endOfLine;
} else if (ch == '*') { // /*comment*/
ch = 0;
do {
ch2 = ch;
ch = getChar();
if (isLineBreak(ch)) {
reader.beginLine();
t.lineBreak = true;
} else if (reader.getEof(ch))
syntaxError("Unterminated /* comment");
} while (ch != '/' || ch2 != '*');
goto next;
} else {
reader.unget();
if (preferRegExp) { // Regular expression
kind = Token::regExp;
lexRegExp();
} else
goto tryAssignment; // /=
}
break;
case '%':
kind = Token::modulo; // %
goto tryAssignment; // %=
case '+':
kind = Token::plus; // +
if (testChar('+'))
kind = Token::increment; // ++
else
goto tryAssignment; // +=
break;
case '-':
kind = Token::minus; // -
ch = getChar();
if (ch == '-')
kind = Token::decrement; // --
else if (ch == '>')
kind = Token::arrow; // ->
else {
reader.unget();
goto tryAssignment; // -=
}
break;
case '&':
kind = Token::bitwiseAnd; // & && &= &&=
logical:
if (testChar(ch))
kind = Token::Kind(kind - Token::bitwiseAnd + Token::logicalAnd);
goto tryAssignment;
case '^':
kind = Token::bitwiseXor; // ^ ^^ ^= ^^=
goto logical;
case '|':
kind = Token::bitwiseOr; // | || |= ||=
goto logical;
case '=':
kind = Token::assignment; // =
if (testChar('=')) {
kind = Token::equal; // ==
if (testChar('='))
kind = Token::identical; // ===
}
break;
case '<':
kind = Token::lessThan; // <
if (testChar('<')) {
kind = Token::leftShift; // <<
goto tryAssignment; // <<=
}
comparison:
if (testChar('=')) // <= >=
kind = Token::Kind(kind + Token::lessThanOrEqual - Token::lessThan);
break;
case '>':
kind = Token::greaterThan; // >
if (testChar('>')) {
kind = Token::rightShift; // >>
if (testChar('>'))
kind = Token::logicalRightShift; // >>>
goto tryAssignment; // >>= >>>=
}
goto comparison;
case '\\':
goto readIdentifier; // An identifier that starts with an escape
case '\'':
case '"':
kind = Token::string; // 'string' "string"
lexString(t.chars, ch);
break;
case '0':
case '1':
case '2':
case '3':
case '4':
case '5':
case '6':
case '7':
case '8':
case '9':
reader.unget(); // Number
number:
kind = Token::number;
#ifdef PARSE_UNIT
lexingUnit =
#else
lexNumeral();
#endif
break;
default:
syntaxError("Bad character");
}
break;
case CharInfo::LineBreakGroup:
endOfLine:
reader.beginLine();
t.lineBreak = true;
goto next;
}
}
}
t.kind = kind;
#ifdef DEBUG
t.valid = true;
#endif
}