third_party/WebKit/Source/core/css/parser/CSSParserTokenRange.cpp

// Copyright 2014 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "core/css/parser/CSSParserTokenRange.h"

#include "wtf/StaticConstructors.h"
#include "wtf/text/StringBuilder.h"

namespace blink {

DEFINE_GLOBAL(CSSParserToken, staticEOFToken);

void CSSParserTokenRange::initStaticEOFToken() {
  new ((void*)&staticEOFToken) CSSParserToken(EOFToken);
}

CSSParserTokenRange CSSParserTokenRange::makeSubRange(
    const CSSParserToken* first,
    const CSSParserToken* last) const {
  if (first == &staticEOFToken)
    first = m_last;
  if (last == &staticEOFToken)
    last = m_last;
  ASSERT(first <= last);
  return CSSParserTokenRange(first, last);
}

CSSParserTokenRange CSSParserTokenRange::consumeBlock() {
  ASSERT(peek().getBlockType() == CSSParserToken::BlockStart);
  const CSSParserToken* start = &peek() + 1;
  unsigned nestingLevel = 0;
  do {
    const CSSParserToken& token = consume();
    if (token.getBlockType() == CSSParserToken::BlockStart)
      nestingLevel++;
    else if (token.getBlockType() == CSSParserToken::BlockEnd)
      nestingLevel--;
  } while (nestingLevel && m_first < m_last);

  if (nestingLevel)
    return makeSubRange(start, m_first);  // Ended at EOF
  return makeSubRange(start, m_first - 1);
}

void CSSParserTokenRange::consumeComponentValue() {
  // FIXME: This is going to do multiple passes over large sections of a
  // stylesheet. We should consider optimising this by precomputing where each
  // block ends.
  unsigned nestingLevel = 0;
  do {
    const CSSParserToken& token = consume();
    if (token.getBlockType() == CSSParserToken::BlockStart)
      nestingLevel++;
    else if (token.getBlockType() == CSSParserToken::BlockEnd)
      nestingLevel--;
  } while (nestingLevel && m_first < m_last);
}

String CSSParserTokenRange::serialize() const {
  // We're supposed to insert comments between certain pairs of token types
  // as per spec, but since this is currently only used for @supports CSSOM
  // we just get these cases wrong and avoid the additional complexity.
  StringBuilder builder;
  for (const CSSParserToken* it = m_first; it < m_last; ++it)
    it->serialize(builder);
  return builder.toString();
}

}  // namespace blink