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/*
* Copyright (C) 2008 Apple Inc. All Rights Reserved.
* Copyright (C) 2009 Torch Mobile, Inc. http://www.torchmobile.com/
* Copyright (C) 2013 Google, Inc. All Rights Reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. 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.
*
* THIS SOFTWARE IS PROVIDED BY APPLE INC. ``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 APPLE INC. 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.
*/
#ifndef InputStreamPreprocessor_h
#define InputStreamPreprocessor_h
#include "SegmentedString.h"
#include <wtf/Noncopyable.h>
namespace WebCore {
const LChar kEndOfFileMarker = 0;
// http://www.whatwg.org/specs/web-apps/current-work/#preprocessing-the-input-stream
template <typename Tokenizer>
class InputStreamPreprocessor {
WTF_MAKE_NONCOPYABLE(InputStreamPreprocessor);
public:
InputStreamPreprocessor(Tokenizer* tokenizer)
: m_tokenizer(tokenizer)
{
reset();
}
ALWAYS_INLINE UChar nextInputCharacter() const { return m_nextInputCharacter; }
// Returns whether we succeeded in peeking at the next character.
// The only way we can fail to peek is if there are no more
// characters in |source| (after collapsing \r\n, etc).
ALWAYS_INLINE bool peek(SegmentedString& source)
{
m_nextInputCharacter = source.currentChar();
// Every branch in this function is expensive, so we have a
// fast-reject branch for characters that don't require special
// handling. Please run the parser benchmark whenever you touch
// this function. It's very hot.
static const UChar specialCharacterMask = '\n' | '\r' | '\0';
if (m_nextInputCharacter & ~specialCharacterMask) {
m_skipNextNewLine = false;
return true;
}
return processNextInputCharacter(source);
}
// Returns whether there are more characters in |source| after advancing.
ALWAYS_INLINE bool advance(SegmentedString& source)
{
source.advanceAndUpdateLineNumber();
if (source.isEmpty())
return false;
return peek(source);
}
bool skipNextNewLine() const { return m_skipNextNewLine; }
void reset(bool skipNextNewLine = false)
{
m_nextInputCharacter = '\0';
m_skipNextNewLine = skipNextNewLine;
}
private:
bool processNextInputCharacter(SegmentedString& source)
{
ProcessAgain:
ASSERT(m_nextInputCharacter == source.currentChar());
if (m_nextInputCharacter == '\n' && m_skipNextNewLine) {
m_skipNextNewLine = false;
source.advancePastNewlineAndUpdateLineNumber();
if (source.isEmpty())
return false;
m_nextInputCharacter = source.currentChar();
}
if (m_nextInputCharacter == '\r') {
m_nextInputCharacter = '\n';
m_skipNextNewLine = true;
} else {
m_skipNextNewLine = false;
// FIXME: The spec indicates that the surrogate pair range as well as
// a number of specific character values are parse errors and should be replaced
// by the replacement character. We suspect this is a problem with the spec as doing
// that filtering breaks surrogate pair handling and causes us not to match Minefield.
if (m_nextInputCharacter == '\0' && !shouldTreatNullAsEndOfFileMarker(source)) {
if (m_tokenizer->shouldSkipNullCharacters()) {
source.advancePastNonNewline();
if (source.isEmpty())
return false;
m_nextInputCharacter = source.currentChar();
goto ProcessAgain;
}
m_nextInputCharacter = 0xFFFD;
}
}
return true;
}
bool shouldTreatNullAsEndOfFileMarker(SegmentedString& source) const
{
return source.isClosed() && source.length() == 1;
}
Tokenizer* m_tokenizer;
// http://www.whatwg.org/specs/web-apps/current-work/#next-input-character
UChar m_nextInputCharacter;
bool m_skipNextNewLine;
};
}
#endif // InputStreamPreprocessor_h
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