solidity/liblangutil/Scanner.cpp
Christian Parpart 435f7b3b72 liblangutil: Scanner: remove superfluous sourceName field (it's in CharStream already)
Also, ParserBase::sourceName() was dead code. Eliminating it should
increase test coverage (how sneaky) :-)
2018-11-30 17:07:17 +01:00

905 lines
22 KiB
C++

/*
This file is part of solidity.
solidity is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
solidity is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with solidity. If not, see <http://www.gnu.org/licenses/>.
This file is derived from the file "scanner.cc", which was part of the
V8 project. The original copyright header follows:
Copyright 2006-2012, 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.
*/
/**
* @author Christian <c@ethdev.com>
* @date 2014
* Solidity scanner.
*/
#include <liblangutil/Exceptions.h>
#include <liblangutil/Scanner.h>
#include <algorithm>
#include <ostream>
#include <tuple>
using namespace std;
namespace langutil
{
namespace
{
bool isDecimalDigit(char c)
{
return '0' <= c && c <= '9';
}
bool isHexDigit(char c)
{
return isDecimalDigit(c)
|| ('a' <= c && c <= 'f')
|| ('A' <= c && c <= 'F');
}
bool isLineTerminator(char c)
{
return c == '\n';
}
bool isWhiteSpace(char c)
{
return c == ' ' || c == '\n' || c == '\t' || c == '\r';
}
bool isIdentifierStart(char c)
{
return c == '_' || c == '$' || ('a' <= c && c <= 'z') || ('A' <= c && c <= 'Z');
}
bool isIdentifierPart(char c)
{
return isIdentifierStart(c) || isDecimalDigit(c);
}
int hexValue(char c)
{
if (c >= '0' && c <= '9')
return c - '0';
else if (c >= 'a' && c <= 'f')
return c - 'a' + 10;
else if (c >= 'A' && c <= 'F')
return c - 'A' + 10;
else return -1;
}
} // end anonymous namespace
std::string to_string(ScannerError _errorCode)
{
switch (_errorCode)
{
case ScannerError::NoError: return "No error.";
case ScannerError::IllegalToken: return "Invalid token.";
case ScannerError::IllegalHexString: return "Expected even number of hex-nibbles within double-quotes.";
case ScannerError::IllegalHexDigit: return "Hexadecimal digit missing or invalid.";
case ScannerError::IllegalCommentTerminator: return "Expected multi-line comment-terminator.";
case ScannerError::IllegalEscapeSequence: return "Invalid escape sequence.";
case ScannerError::IllegalStringEndQuote: return "Expected string end-quote.";
case ScannerError::IllegalNumberSeparator: return "Invalid use of number separator '_'.";
case ScannerError::IllegalExponent: return "Invalid exponent.";
case ScannerError::IllegalNumberEnd: return "Identifier-start is not allowed at end of a number.";
case ScannerError::OctalNotAllowed: return "Octal numbers not allowed.";
default:
solAssert(false, "Unhandled case in to_string(ScannerError)");
return "";
}
}
std::ostream& operator<<(std::ostream& os, ScannerError _errorCode)
{
os << to_string(_errorCode);
return os;
}
/// Scoped helper for literal recording. Automatically drops the literal
/// if aborting the scanning before it's complete.
enum LiteralType {
LITERAL_TYPE_STRING,
LITERAL_TYPE_NUMBER, // not really different from string type in behaviour
LITERAL_TYPE_COMMENT
};
class LiteralScope
{
public:
explicit LiteralScope(Scanner* _self, enum LiteralType _type): m_type(_type)
, m_scanner(_self)
, m_complete(false)
{
if (_type == LITERAL_TYPE_COMMENT)
m_scanner->m_nextSkippedComment.literal.clear();
else
m_scanner->m_nextToken.literal.clear();
}
~LiteralScope()
{
if (!m_complete)
{
if (m_type == LITERAL_TYPE_COMMENT)
m_scanner->m_nextSkippedComment.literal.clear();
else
m_scanner->m_nextToken.literal.clear();
}
}
void complete() { m_complete = true; }
private:
enum LiteralType m_type;
Scanner* m_scanner;
bool m_complete;
}; // end of LiteralScope class
void Scanner::reset(CharStream _source)
{
m_source = make_shared<CharStream>(std::move(_source));
reset();
}
void Scanner::reset(std::shared_ptr<CharStream> _source)
{
solAssert(_source.get() != nullptr, "You MUST provide a CharStream when resetting.");
m_source = _source;
reset();
}
void Scanner::reset()
{
m_source->reset();
m_char = m_source->get();
skipWhitespace();
scanToken();
next();
}
bool Scanner::scanHexByte(char& o_scannedByte)
{
char x = 0;
for (int i = 0; i < 2; i++)
{
int d = hexValue(m_char);
if (d < 0)
{
rollback(i);
return false;
}
x = x * 16 + d;
advance();
}
o_scannedByte = x;
return true;
}
bool Scanner::scanUnicode(unsigned & o_codepoint)
{
unsigned x = 0;
for (int i = 0; i < 4; i++)
{
int d = hexValue(m_char);
if (d < 0)
{
rollback(i);
return false;
}
x = x * 16 + d;
advance();
}
o_codepoint = x;
return true;
}
// This supports codepoints between 0000 and FFFF.
void Scanner::addUnicodeAsUTF8(unsigned codepoint)
{
if (codepoint <= 0x7f)
addLiteralChar(codepoint);
else if (codepoint <= 0x7ff)
{
addLiteralChar(0xc0 | (codepoint >> 6));
addLiteralChar(0x80 | (codepoint & 0x3f));
}
else
{
addLiteralChar(0xe0 | (codepoint >> 12));
addLiteralChar(0x80 | ((codepoint >> 6) & 0x3f));
addLiteralChar(0x80 | (codepoint & 0x3f));
}
}
// Ensure that tokens can be stored in a byte.
BOOST_STATIC_ASSERT(TokenTraits::count() <= 0x100);
Token Scanner::next()
{
m_currentToken = m_nextToken;
m_skippedComment = m_nextSkippedComment;
scanToken();
return m_currentToken.token;
}
Token Scanner::selectToken(char _next, Token _then, Token _else)
{
advance();
if (m_char == _next)
return selectToken(_then);
else
return _else;
}
bool Scanner::skipWhitespace()
{
int const startPosition = sourcePos();
while (isWhiteSpace(m_char))
advance();
// Return whether or not we skipped any characters.
return sourcePos() != startPosition;
}
void Scanner::skipWhitespaceExceptUnicodeLinebreak()
{
while (isWhiteSpace(m_char) && !isUnicodeLinebreak())
advance();
}
Token Scanner::skipSingleLineComment()
{
// Line terminator is not part of the comment. If it is a
// non-ascii line terminator, it will result in a parser error.
while (!isUnicodeLinebreak())
if (!advance()) break;
return Token::Whitespace;
}
Token Scanner::scanSingleLineDocComment()
{
LiteralScope literal(this, LITERAL_TYPE_COMMENT);
advance(); //consume the last '/' at ///
skipWhitespaceExceptUnicodeLinebreak();
while (!isSourcePastEndOfInput())
{
if (isLineTerminator(m_char))
{
// check if next line is also a documentation comment
skipWhitespace();
if (!m_source->isPastEndOfInput(3) &&
m_source->get(0) == '/' &&
m_source->get(1) == '/' &&
m_source->get(2) == '/')
{
addCommentLiteralChar('\n');
m_char = m_source->advanceAndGet(3);
}
else
break; // next line is not a documentation comment, we are done
}
else if (isUnicodeLinebreak())
// Any line terminator that is not '\n' is considered to end the
// comment.
break;
addCommentLiteralChar(m_char);
advance();
}
literal.complete();
return Token::CommentLiteral;
}
Token Scanner::skipMultiLineComment()
{
advance();
while (!isSourcePastEndOfInput())
{
char ch = m_char;
advance();
// 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 == '*' && m_char == '/')
{
m_char = ' ';
return Token::Whitespace;
}
}
// Unterminated multi-line comment.
return setError(ScannerError::IllegalCommentTerminator);
}
Token Scanner::scanMultiLineDocComment()
{
LiteralScope literal(this, LITERAL_TYPE_COMMENT);
bool endFound = false;
bool charsAdded = false;
while (isWhiteSpace(m_char) && !isLineTerminator(m_char))
advance();
while (!isSourcePastEndOfInput())
{
//handle newlines in multline comments
if (isLineTerminator(m_char))
{
skipWhitespace();
if (!m_source->isPastEndOfInput(1) && m_source->get(0) == '*' && m_source->get(1) == '*')
{ // it is unknown if this leads to the end of the comment
addCommentLiteralChar('*');
advance();
}
else if (!m_source->isPastEndOfInput(1) && m_source->get(0) == '*' && m_source->get(1) != '/')
{ // skip first '*' in subsequent lines
if (charsAdded)
addCommentLiteralChar('\n');
m_char = m_source->advanceAndGet(2);
}
else if (!m_source->isPastEndOfInput(1) && m_source->get(0) == '*' && m_source->get(1) == '/')
{ // if after newline the comment ends, don't insert the newline
m_char = m_source->advanceAndGet(2);
endFound = true;
break;
}
else if (charsAdded)
addCommentLiteralChar('\n');
}
if (!m_source->isPastEndOfInput(1) && m_source->get(0) == '*' && m_source->get(1) == '/')
{
m_char = m_source->advanceAndGet(2);
endFound = true;
break;
}
addCommentLiteralChar(m_char);
charsAdded = true;
advance();
}
literal.complete();
if (!endFound)
return setError(ScannerError::IllegalCommentTerminator);
else
return Token::CommentLiteral;
}
Token Scanner::scanSlash()
{
int firstSlashPosition = sourcePos();
advance();
if (m_char == '/')
{
if (!advance()) /* double slash comment directly before EOS */
return Token::Whitespace;
else if (m_char == '/')
{
// doxygen style /// comment
Token comment;
m_nextSkippedComment.location.start = firstSlashPosition;
comment = scanSingleLineDocComment();
m_nextSkippedComment.location.end = sourcePos();
m_nextSkippedComment.token = comment;
return Token::Whitespace;
}
else
return skipSingleLineComment();
}
else if (m_char == '*')
{
// doxygen style /** natspec comment
if (!advance()) /* slash star comment before EOS */
return setError(ScannerError::IllegalCommentTerminator);
else if (m_char == '*')
{
advance(); //consume the last '*' at /**
// "/**/"
if (m_char == '/')
{
advance(); //skip the closing slash
return Token::Whitespace;
}
// we actually have a multiline documentation comment
Token comment;
m_nextSkippedComment.location.start = firstSlashPosition;
comment = scanMultiLineDocComment();
m_nextSkippedComment.location.end = sourcePos();
m_nextSkippedComment.token = comment;
if (comment == Token::Illegal)
return Token::Illegal; // error already set
else
return Token::Whitespace;
}
else
return skipMultiLineComment();
}
else if (m_char == '=')
return selectToken(Token::AssignDiv);
else
return Token::Div;
}
void Scanner::scanToken()
{
m_nextToken.error = ScannerError::NoError;
m_nextToken.literal.clear();
m_nextToken.extendedTokenInfo = make_tuple(0, 0);
m_nextSkippedComment.literal.clear();
m_nextSkippedComment.extendedTokenInfo = make_tuple(0, 0);
Token token;
// M and N are for the purposes of grabbing different type sizes
unsigned m;
unsigned n;
do
{
// Remember the position of the next token
m_nextToken.location.start = sourcePos();
switch (m_char)
{
case '"':
case '\'':
token = scanString();
break;
case '<':
// < <= << <<=
advance();
if (m_char == '=')
token = selectToken(Token::LessThanOrEqual);
else if (m_char == '<')
token = selectToken('=', Token::AssignShl, Token::SHL);
else
token = Token::LessThan;
break;
case '>':
// > >= >> >>= >>> >>>=
advance();
if (m_char == '=')
token = selectToken(Token::GreaterThanOrEqual);
else if (m_char == '>')
{
// >> >>= >>> >>>=
advance();
if (m_char == '=')
token = selectToken(Token::AssignSar);
else if (m_char == '>')
token = selectToken('=', Token::AssignShr, Token::SHR);
else
token = Token::SAR;
}
else
token = Token::GreaterThan;
break;
case '=':
// = == =>
advance();
if (m_char == '=')
token = selectToken(Token::Equal);
else if (m_char == '>')
token = selectToken(Token::Arrow);
else
token = Token::Assign;
break;
case '!':
// ! !=
advance();
if (m_char == '=')
token = selectToken(Token::NotEqual);
else
token = Token::Not;
break;
case '+':
// + ++ +=
advance();
if (m_char == '+')
token = selectToken(Token::Inc);
else if (m_char == '=')
token = selectToken(Token::AssignAdd);
else
token = Token::Add;
break;
case '-':
// - -- -=
advance();
if (m_char == '-')
token = selectToken(Token::Dec);
else if (m_char == '=')
token = selectToken(Token::AssignSub);
else
token = Token::Sub;
break;
case '*':
// * ** *=
advance();
if (m_char == '*')
token = selectToken(Token::Exp);
else if (m_char == '=')
token = selectToken(Token::AssignMul);
else
token = Token::Mul;
break;
case '%':
// % %=
token = selectToken('=', Token::AssignMod, Token::Mod);
break;
case '/':
// / // /* /=
token = scanSlash();
break;
case '&':
// & && &=
advance();
if (m_char == '&')
token = selectToken(Token::And);
else if (m_char == '=')
token = selectToken(Token::AssignBitAnd);
else
token = Token::BitAnd;
break;
case '|':
// | || |=
advance();
if (m_char == '|')
token = selectToken(Token::Or);
else if (m_char == '=')
token = selectToken(Token::AssignBitOr);
else
token = Token::BitOr;
break;
case '^':
// ^ ^=
token = selectToken('=', Token::AssignBitXor, Token::BitXor);
break;
case '.':
// . Number
advance();
if (isDecimalDigit(m_char))
token = scanNumber('.');
else
token = Token::Period;
break;
case ':':
token = selectToken(Token::Colon);
break;
case ';':
token = selectToken(Token::Semicolon);
break;
case ',':
token = selectToken(Token::Comma);
break;
case '(':
token = selectToken(Token::LParen);
break;
case ')':
token = selectToken(Token::RParen);
break;
case '[':
token = selectToken(Token::LBrack);
break;
case ']':
token = selectToken(Token::RBrack);
break;
case '{':
token = selectToken(Token::LBrace);
break;
case '}':
token = selectToken(Token::RBrace);
break;
case '?':
token = selectToken(Token::Conditional);
break;
case '~':
token = selectToken(Token::BitNot);
break;
default:
if (isIdentifierStart(m_char))
{
tie(token, m, n) = scanIdentifierOrKeyword();
// Special case for hexadecimal literals
if (token == Token::Hex)
{
// reset
m = 0;
n = 0;
// Special quoted hex string must follow
if (m_char == '"' || m_char == '\'')
token = scanHexString();
else
token = setError(ScannerError::IllegalToken);
}
}
else if (isDecimalDigit(m_char))
token = scanNumber();
else if (skipWhitespace())
token = Token::Whitespace;
else if (isSourcePastEndOfInput())
token = Token::EOS;
else
token = selectErrorToken(ScannerError::IllegalToken);
break;
}
// Continue scanning for tokens as long as we're just skipping
// whitespace.
}
while (token == Token::Whitespace);
m_nextToken.location.end = sourcePos();
m_nextToken.token = token;
m_nextToken.extendedTokenInfo = make_tuple(m, n);
}
bool Scanner::scanEscape()
{
char c = m_char;
advance();
// Skip escaped newlines.
if (isLineTerminator(c))
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 'v':
c = '\v';
break;
case 'u':
{
unsigned codepoint;
if (!scanUnicode(codepoint))
return false;
addUnicodeAsUTF8(codepoint);
return true;
}
case 'x':
if (!scanHexByte(c))
return false;
break;
default:
return false;
}
addLiteralChar(c);
return true;
}
bool Scanner::isUnicodeLinebreak()
{
if (0x0a <= m_char && m_char <= 0x0d)
// line feed, vertical tab, form feed, carriage return
return true;
else if (!m_source->isPastEndOfInput(1) && uint8_t(m_source->get(0)) == 0xc2 && uint8_t(m_source->get(1)) == 0x85)
// NEL - U+0085, C2 85 in utf8
return true;
else if (!m_source->isPastEndOfInput(2) && uint8_t(m_source->get(0)) == 0xe2 && uint8_t(m_source->get(1)) == 0x80 && (
uint8_t(m_source->get(2)) == 0xa8 || uint8_t(m_source->get(2)) == 0xa9
))
// LS - U+2028, E2 80 A8 in utf8
// PS - U+2029, E2 80 A9 in utf8
return true;
else
return false;
}
Token Scanner::scanString()
{
char const quote = m_char;
advance(); // consume quote
LiteralScope literal(this, LITERAL_TYPE_STRING);
while (m_char != quote && !isSourcePastEndOfInput() && !isUnicodeLinebreak())
{
char c = m_char;
advance();
if (c == '\\')
{
if (isSourcePastEndOfInput() || !scanEscape())
return setError(ScannerError::IllegalEscapeSequence);
}
else
addLiteralChar(c);
}
if (m_char != quote)
return setError(ScannerError::IllegalStringEndQuote);
literal.complete();
advance(); // consume quote
return Token::StringLiteral;
}
Token Scanner::scanHexString()
{
char const quote = m_char;
advance(); // consume quote
LiteralScope literal(this, LITERAL_TYPE_STRING);
while (m_char != quote && !isSourcePastEndOfInput())
{
char c = m_char;
if (!scanHexByte(c))
// can only return false if hex-byte is incomplete (only one hex digit instead of two)
return setError(ScannerError::IllegalHexString);
addLiteralChar(c);
}
if (m_char != quote)
return setError(ScannerError::IllegalStringEndQuote);
literal.complete();
advance(); // consume quote
return Token::StringLiteral;
}
// Parse for regex [:digit:]+(_[:digit:]+)*
void Scanner::scanDecimalDigits()
{
// MUST begin with a decimal digit.
if (!isDecimalDigit(m_char))
return;
// May continue with decimal digit or underscore for grouping.
do addLiteralCharAndAdvance();
while (!m_source->isPastEndOfInput() && (isDecimalDigit(m_char) || m_char == '_'));
// Defer further validation of underscore to SyntaxChecker.
}
Token Scanner::scanNumber(char _charSeen)
{
enum { DECIMAL, HEX, BINARY } kind = DECIMAL;
LiteralScope literal(this, LITERAL_TYPE_NUMBER);
if (_charSeen == '.')
{
// we have already seen a decimal point of the float
addLiteralChar('.');
if (m_char == '_')
return setError(ScannerError::IllegalToken);
scanDecimalDigits(); // we know we have at least one digit
}
else
{
solAssert(_charSeen == 0, "");
// if the first character is '0' we must check for octals and hex
if (m_char == '0')
{
addLiteralCharAndAdvance();
// either 0, 0exxx, 0Exxx, 0.xxx or a hex number
if (m_char == 'x')
{
// hex number
kind = HEX;
addLiteralCharAndAdvance();
if (!isHexDigit(m_char))
return setError(ScannerError::IllegalHexDigit); // we must have at least one hex digit after 'x'
while (isHexDigit(m_char) || m_char == '_') // We keep the underscores for later validation
addLiteralCharAndAdvance();
}
else if (isDecimalDigit(m_char))
// We do not allow octal numbers
return setError(ScannerError::OctalNotAllowed);
}
// Parse decimal digits and allow trailing fractional part.
if (kind == DECIMAL)
{
scanDecimalDigits(); // optional
if (m_char == '.')
{
if (!m_source->isPastEndOfInput(1) && m_source->get(1) == '_')
{
// Assume the input may be a floating point number with leading '_' in fraction part.
// Recover by consuming it all but returning `Illegal` right away.
addLiteralCharAndAdvance(); // '.'
addLiteralCharAndAdvance(); // '_'
scanDecimalDigits();
}
if (m_source->isPastEndOfInput() || !isDecimalDigit(m_source->get(1)))
{
// A '.' has to be followed by a number.
literal.complete();
return Token::Number;
}
addLiteralCharAndAdvance();
scanDecimalDigits();
}
}
}
// scan exponent, if any
if (m_char == 'e' || m_char == 'E')
{
solAssert(kind != HEX, "'e'/'E' must be scanned as part of the hex number");
if (kind != DECIMAL)
return setError(ScannerError::IllegalExponent);
else if (!m_source->isPastEndOfInput(1) && m_source->get(1) == '_')
{
// Recover from wrongly placed underscore as delimiter in literal with scientific
// notation by consuming until the end.
addLiteralCharAndAdvance(); // 'e'
addLiteralCharAndAdvance(); // '_'
scanDecimalDigits();
literal.complete();
return Token::Number;
}
// scan exponent
addLiteralCharAndAdvance(); // 'e' | 'E'
if (m_char == '+' || m_char == '-')
addLiteralCharAndAdvance();
if (!isDecimalDigit(m_char)) // we must have at least one decimal digit after 'e'/'E'
return setError(ScannerError::IllegalExponent);
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(m_char) || isIdentifierStart(m_char))
return setError(ScannerError::IllegalNumberEnd);
literal.complete();
return Token::Number;
}
tuple<Token, unsigned, unsigned> Scanner::scanIdentifierOrKeyword()
{
solAssert(isIdentifierStart(m_char), "");
LiteralScope literal(this, LITERAL_TYPE_STRING);
addLiteralCharAndAdvance();
// Scan the rest of the identifier characters.
while (isIdentifierPart(m_char)) //get full literal
addLiteralCharAndAdvance();
literal.complete();
return TokenTraits::fromIdentifierOrKeyword(m_nextToken.literal);
}
}