// 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.
#include "v8.h"
#include "ast.h"
#include "handles.h"
#include "scanner.h"
#include "unicode-inl.h"
namespace v8 {
namespace internal {
// ----------------------------------------------------------------------------
// BufferedUC16CharacterStreams
BufferedUC16CharacterStream::BufferedUC16CharacterStream()
: UC16CharacterStream(),
pushback_limit_(NULL) {
// Initialize buffer as being empty. First read will fill the buffer.
buffer_cursor_ = buffer_;
buffer_end_ = buffer_;
}
BufferedUC16CharacterStream::~BufferedUC16CharacterStream() { }
void BufferedUC16CharacterStream::PushBack(uc32 character) {
if (character == kEndOfInput) {
pos_--;
return;
}
if (pushback_limit_ == NULL && buffer_cursor_ > buffer_) {
// buffer_ is writable, buffer_cursor_ is const pointer.
buffer_[--buffer_cursor_ - buffer_] = static_cast<uc16>(character);
pos_--;
return;
}
SlowPushBack(static_cast<uc16>(character));
}
void BufferedUC16CharacterStream::SlowPushBack(uc16 character) {
// In pushback mode, the end of the buffer contains pushback,
// and the start of the buffer (from buffer start to pushback_limit_)
// contains valid data that comes just after the pushback.
// We NULL the pushback_limit_ if pushing all the way back to the
// start of the buffer.
if (pushback_limit_ == NULL) {
// Enter pushback mode.
pushback_limit_ = buffer_end_;
buffer_end_ = buffer_ + kBufferSize;
buffer_cursor_ = buffer_end_;
}
// Ensure that there is room for at least one pushback.
ASSERT(buffer_cursor_ > buffer_);
ASSERT(pos_ > 0);
buffer_[--buffer_cursor_ - buffer_] = character;
if (buffer_cursor_ == buffer_) {
pushback_limit_ = NULL;
} else if (buffer_cursor_ < pushback_limit_) {
pushback_limit_ = buffer_cursor_;
}
pos_--;
}
bool BufferedUC16CharacterStream::ReadBlock() {
buffer_cursor_ = buffer_;
if (pushback_limit_ != NULL) {
// Leave pushback mode.
buffer_end_ = pushback_limit_;
pushback_limit_ = NULL;
// If there were any valid characters left at the
// start of the buffer, use those.
if (buffer_cursor_ < buffer_end_) return true;
// Otherwise read a new block.
}
unsigned length = FillBuffer(pos_, kBufferSize);
buffer_end_ = buffer_ + length;
return length > 0;
}
unsigned BufferedUC16CharacterStream::SlowSeekForward(unsigned delta) {
// Leave pushback mode (i.e., ignore that there might be valid data
// in the buffer before the pushback_limit_ point).
pushback_limit_ = NULL;
return BufferSeekForward(delta);
}
// ----------------------------------------------------------------------------
// GenericStringUC16CharacterStream
GenericStringUC16CharacterStream::GenericStringUC16CharacterStream(
Handle<String> data,
unsigned start_position,
unsigned end_position)
: string_(data),
length_(end_position) {
ASSERT(end_position >= start_position);
buffer_cursor_ = buffer_;
buffer_end_ = buffer_;
pos_ = start_position;
}
GenericStringUC16CharacterStream::~GenericStringUC16CharacterStream() { }
unsigned GenericStringUC16CharacterStream::BufferSeekForward(unsigned delta) {
unsigned old_pos = pos_;
pos_ = Min(pos_ + delta, length_);
ReadBlock();
return pos_ - old_pos;
}
unsigned GenericStringUC16CharacterStream::FillBuffer(unsigned from_pos,
unsigned length) {
if (from_pos >= length_) return 0;
if (from_pos + length > length_) {
length = length_ - from_pos;
}
String::WriteToFlat<uc16>(*string_, buffer_, from_pos, from_pos + length);
return length;
}
// ----------------------------------------------------------------------------
// Utf8ToUC16CharacterStream
Utf8ToUC16CharacterStream::Utf8ToUC16CharacterStream(const byte* data,
unsigned length)
: BufferedUC16CharacterStream(),
raw_data_(data),
raw_data_length_(length),
raw_data_pos_(0),
raw_character_position_(0) {
ReadBlock();
}
Utf8ToUC16CharacterStream::~Utf8ToUC16CharacterStream() { }
unsigned Utf8ToUC16CharacterStream::BufferSeekForward(unsigned delta) {
unsigned old_pos = pos_;
unsigned target_pos = pos_ + delta;
SetRawPosition(target_pos);
pos_ = raw_character_position_;
ReadBlock();
return pos_ - old_pos;
}
unsigned Utf8ToUC16CharacterStream::FillBuffer(unsigned char_position,
unsigned length) {
static const unibrow::uchar kMaxUC16Character = 0xffff;
SetRawPosition(char_position);
if (raw_character_position_ != char_position) {
// char_position was not a valid position in the stream (hit the end
// while spooling to it).
return 0u;
}
unsigned i = 0;
while (i < length) {
if (raw_data_pos_ == raw_data_length_) break;
unibrow::uchar c = raw_data_[raw_data_pos_];
if (c <= unibrow::Utf8::kMaxOneByteChar) {
raw_data_pos_++;
} else {
c = unibrow::Utf8::CalculateValue(raw_data_ + raw_data_pos_,
raw_data_length_ - raw_data_pos_,
&raw_data_pos_);
// Don't allow characters outside of the BMP.
if (c > kMaxUC16Character) {
c = unibrow::Utf8::kBadChar;
}
}
buffer_[i++] = static_cast<uc16>(c);
}
raw_character_position_ = char_position + i;
return i;
}
static const byte kUtf8MultiByteMask = 0xC0;
static const byte kUtf8MultiByteCharStart = 0xC0;
static const byte kUtf8MultiByteCharFollower = 0x80;
#ifdef DEBUG
static bool IsUtf8MultiCharacterStart(byte first_byte) {
return (first_byte & kUtf8MultiByteMask) == kUtf8MultiByteCharStart;
}
#endif
static bool IsUtf8MultiCharacterFollower(byte later_byte) {
return (later_byte & kUtf8MultiByteMask) == kUtf8MultiByteCharFollower;
}
// Move the cursor back to point at the preceding UTF-8 character start
// in the buffer.
static inline void Utf8CharacterBack(const byte* buffer, unsigned* cursor) {
byte character = buffer[--*cursor];
if (character > unibrow::Utf8::kMaxOneByteChar) {
ASSERT(IsUtf8MultiCharacterFollower(character));
// Last byte of a multi-byte character encoding. Step backwards until
// pointing to the first byte of the encoding, recognized by having the
// top two bits set.
while (IsUtf8MultiCharacterFollower(buffer[--*cursor])) { }
ASSERT(IsUtf8MultiCharacterStart(buffer[*cursor]));
}
}
// Move the cursor forward to point at the next following UTF-8 character start
// in the buffer.
static inline void Utf8CharacterForward(const byte* buffer, unsigned* cursor) {
byte character = buffer[(*cursor)++];
if (character > unibrow::Utf8::kMaxOneByteChar) {
// First character of a multi-byte character encoding.
// The number of most-significant one-bits determines the length of the
// encoding:
// 110..... - (0xCx, 0xDx) one additional byte (minimum).
// 1110.... - (0xEx) two additional bytes.
// 11110... - (0xFx) three additional bytes (maximum).
ASSERT(IsUtf8MultiCharacterStart(character));
// Additional bytes is:
// 1 if value in range 0xC0 .. 0xDF.
// 2 if value in range 0xE0 .. 0xEF.
// 3 if value in range 0xF0 .. 0xF7.
// Encode that in a single value.
unsigned additional_bytes =
((0x3211u) >> (((character - 0xC0) >> 2) & 0xC)) & 0x03;
*cursor += additional_bytes;
ASSERT(!IsUtf8MultiCharacterFollower(buffer[1 + additional_bytes]));
}
}
void Utf8ToUC16CharacterStream::SetRawPosition(unsigned target_position) {
if (raw_character_position_ > target_position) {
// Spool backwards in utf8 buffer.
do {
Utf8CharacterBack(raw_data_, &raw_data_pos_);
raw_character_position_--;
} while (raw_character_position_ > target_position);
return;
}
// Spool forwards in the utf8 buffer.
while (raw_character_position_ < target_position) {
if (raw_data_pos_ == raw_data_length_) return;
Utf8CharacterForward(raw_data_, &raw_data_pos_);
raw_character_position_++;
}
}
// ----------------------------------------------------------------------------
// ExternalTwoByteStringUC16CharacterStream
ExternalTwoByteStringUC16CharacterStream::
~ExternalTwoByteStringUC16CharacterStream() { }
ExternalTwoByteStringUC16CharacterStream
::ExternalTwoByteStringUC16CharacterStream(
Handle<ExternalTwoByteString> data,
int start_position,
int end_position)
: UC16CharacterStream(),
source_(data),
raw_data_(data->GetTwoByteData(start_position)) {
buffer_cursor_ = raw_data_,
buffer_end_ = raw_data_ + (end_position - start_position);
pos_ = start_position;
}
// ----------------------------------------------------------------------------
// Scanner::LiteralScope
Scanner::LiteralScope::LiteralScope(Scanner* self)
: scanner_(self), complete_(false) {
self->StartLiteral();
}
Scanner::LiteralScope::~LiteralScope() {
if (!complete_) scanner_->DropLiteral();
}
void Scanner::LiteralScope::Complete() {
scanner_->TerminateLiteral();
complete_ = true;
}
// ----------------------------------------------------------------------------
// V8JavaScriptScanner
void V8JavaScriptScanner::Initialize(UC16CharacterStream* 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();
}
// ----------------------------------------------------------------------------
// JsonScanner
JsonScanner::JsonScanner(UnicodeCache* unicode_cache)
: Scanner(unicode_cache) { }
void JsonScanner::Initialize(UC16CharacterStream* source) {
source_ = source;
Init();
// Skip initial whitespace.
SkipJsonWhiteSpace();
// Preload first token as look-ahead.
ScanJson();
}
Token::Value JsonScanner::Next() {
// BUG 1215673: Find a thread safe way to set a stack limit in
// pre-parse mode. Otherwise, we cannot safely pre-parse from other
// threads.
current_ = next_;
// Check for stack-overflow before returning any tokens.
ScanJson();
return current_.token;
}
bool JsonScanner::SkipJsonWhiteSpace() {
int start_position = source_pos();
// JSON WhiteSpace is tab, carrige-return, newline and space.
while (c0_ == ' ' || c0_ == '\n' || c0_ == '\r' || c0_ == '\t') {
Advance();
}
return source_pos() != start_position;
}
void JsonScanner::ScanJson() {
next_.literal_chars = NULL;
Token::Value token;
do {
// Remember the position of the next token
next_.location.beg_pos = source_pos();
switch (c0_) {
case '\t':
case '\r':
case '\n':
case ' ':
Advance();
token = Token::WHITESPACE;
break;
case '{':
Advance();
token = Token::LBRACE;
break;
case '}':
Advance();
token = Token::RBRACE;
break;
case '[':
Advance();
token = Token::LBRACK;
break;
case ']':
Advance();
token = Token::RBRACK;
break;
case ':':
Advance();
token = Token::COLON;
break;
case ',':
Advance();
token = Token::COMMA;
break;
case '"':
token = ScanJsonString();
break;
case '-':
case '0':
case '1':
case '2':
case '3':
case '4':
case '5':
case '6':
case '7':
case '8':
case '9':
token = ScanJsonNumber();
break;
case 't':
token = ScanJsonIdentifier("true", Token::TRUE_LITERAL);
break;
case 'f':
token = ScanJsonIdentifier("false", Token::FALSE_LITERAL);
break;
case 'n':
token = ScanJsonIdentifier("null", Token::NULL_LITERAL);
break;
default:
if (c0_ < 0) {
Advance();
token = Token::EOS;
} else {
Advance();
token = Select(Token::ILLEGAL);
}
}
} while (token == Token::WHITESPACE);
next_.location.end_pos = source_pos();
next_.token = token;
}
Token::Value JsonScanner::ScanJsonString() {
ASSERT_EQ('"', c0_);
Advance();
LiteralScope literal(this);
while (c0_ != '"') {
// Check for control character (0x00-0x1f) or unterminated string (<0).
if (c0_ < 0x20) return Token::ILLEGAL;
if (c0_ != '\\') {
AddLiteralCharAdvance();
} else {
Advance();
switch (c0_) {
case '"':
case '\\':
case '/':
AddLiteralChar(c0_);
break;
case 'b':
AddLiteralChar('\x08');
break;
case 'f':
AddLiteralChar('\x0c');
break;
case 'n':
AddLiteralChar('\x0a');
break;
case 'r':
AddLiteralChar('\x0d');
break;
case 't':
AddLiteralChar('\x09');
break;
case 'u': {
uc32 value = 0;
for (int i = 0; i < 4; i++) {
Advance();
int digit = HexValue(c0_);
if (digit < 0) {
return Token::ILLEGAL;
}
value = value * 16 + digit;
}
AddLiteralChar(value);
break;
}
default:
return Token::ILLEGAL;
}
Advance();
}
}
literal.Complete();
Advance();
return Token::STRING;
}
Token::Value JsonScanner::ScanJsonNumber() {
LiteralScope literal(this);
bool negative = false;
if (c0_ == '-') {
AddLiteralCharAdvance();
negative = true;
}
if (c0_ == '0') {
AddLiteralCharAdvance();
// Prefix zero is only allowed if it's the only digit before
// a decimal point or exponent.
if ('0' <= c0_ && c0_ <= '9') return Token::ILLEGAL;
} else {
int i = 0;
int digits = 0;
if (c0_ < '1' || c0_ > '9') return Token::ILLEGAL;
do {
i = i * 10 + c0_ - '0';
digits++;
AddLiteralCharAdvance();
} while (c0_ >= '0' && c0_ <= '9');
if (c0_ != '.' && c0_ != 'e' && c0_ != 'E' && digits < 10) {
number_ = (negative ? -i : i);
return Token::NUMBER;
}
}
if (c0_ == '.') {
AddLiteralCharAdvance();
if (c0_ < '0' || c0_ > '9') return Token::ILLEGAL;
do {
AddLiteralCharAdvance();
} while (c0_ >= '0' && c0_ <= '9');
}
if (AsciiAlphaToLower(c0_) == 'e') {
AddLiteralCharAdvance();
if (c0_ == '-' || c0_ == '+') AddLiteralCharAdvance();
if (c0_ < '0' || c0_ > '9') return Token::ILLEGAL;
do {
AddLiteralCharAdvance();
} while (c0_ >= '0' && c0_ <= '9');
}
literal.Complete();
ASSERT_NOT_NULL(next_.literal_chars);
number_ = StringToDouble(unicode_cache_,
next_.literal_chars->ascii_literal(),
NO_FLAGS, // Hex, octal or trailing junk.
OS::nan_value());
return Token::NUMBER;
}
Token::Value JsonScanner::ScanJsonIdentifier(const char* text,
Token::Value token) {
LiteralScope literal(this);
while (*text != '\0') {
if (c0_ != *text) return Token::ILLEGAL;
Advance();
text++;
}
if (unicode_cache_->IsIdentifierPart(c0_)) return Token::ILLEGAL;
literal.Complete();
return token;
}
} } // namespace v8::internal