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// 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 "config.h"
#include "core/css/parser/SizesAttributeParser.h"
#include "core/MediaTypeNames.h"
#include "core/css/MediaQueryEvaluator.h"
#include "core/css/parser/MediaQueryTokenizer.h"
#include "core/css/parser/SizesCalcParser.h"
namespace WebCore {
unsigned SizesAttributeParser::findEffectiveSize(const String& attribute, PassRefPtr<MediaValues> mediaValues)
{
Vector<MediaQueryToken> tokens;
SizesAttributeParser parser(mediaValues);
MediaQueryTokenizer::tokenize(attribute, tokens);
if (!parser.parse(tokens))
return parser.effectiveSizeDefaultValue();
return parser.effectiveSize();
}
bool SizesAttributeParser::calculateLengthInPixels(MediaQueryTokenIterator startToken, MediaQueryTokenIterator endToken, unsigned& result)
{
if (startToken == endToken)
return false;
MediaQueryTokenType type = startToken->type();
if (type == DimensionToken) {
int length;
if (!CSSPrimitiveValue::isLength(startToken->unitType()))
return false;
if ((m_mediaValues->computeLength(startToken->numericValue(), startToken->unitType(), length)) && (length > 0)) {
result = (unsigned)length;
return true;
}
} else if (type == FunctionToken) {
return SizesCalcParser::parse(startToken, endToken, m_mediaValues, result);
} else if (type == NumberToken && !startToken->numericValue()) {
result = 0;
return true;
}
return false;
}
static void reverseSkipIrrelevantTokens(MediaQueryTokenIterator& token, MediaQueryTokenIterator startToken)
{
MediaQueryTokenIterator endToken = token;
while (token != startToken && (token->type() == WhitespaceToken || token->type() == CommentToken || token->type() == EOFToken))
--token;
if (token != endToken)
++token;
}
static void reverseSkipUntilComponentStart(MediaQueryTokenIterator& token, MediaQueryTokenIterator startToken)
{
if (token == startToken)
return;
--token;
if (token->blockType() != MediaQueryToken::BlockEnd)
return;
unsigned blockLevel = 0;
while (token != startToken) {
if (token->blockType() == MediaQueryToken::BlockEnd) {
++blockLevel;
} else if (token->blockType() == MediaQueryToken::BlockStart) {
--blockLevel;
if (!blockLevel)
break;
}
--token;
}
}
bool SizesAttributeParser::mediaConditionMatches(PassRefPtrWillBeRawPtr<MediaQuerySet> mediaCondition)
{
// A Media Condition cannot have a media type other then screen.
MediaQueryEvaluator mediaQueryEvaluator(MediaTypeNames::screen, *m_mediaValues);
return mediaQueryEvaluator.eval(mediaCondition.get());
}
bool SizesAttributeParser::parseMediaConditionAndLength(MediaQueryTokenIterator startToken, MediaQueryTokenIterator endToken)
{
MediaQueryTokenIterator lengthTokenStart;
MediaQueryTokenIterator lengthTokenEnd;
reverseSkipIrrelevantTokens(endToken, startToken);
lengthTokenEnd = endToken;
reverseSkipUntilComponentStart(endToken, startToken);
lengthTokenStart = endToken;
unsigned length;
if (!calculateLengthInPixels(lengthTokenStart, lengthTokenEnd, length))
return false;
RefPtrWillBeRawPtr<MediaQuerySet> mediaCondition = MediaQueryParser::parseMediaCondition(startToken, endToken);
if (mediaCondition && mediaConditionMatches(mediaCondition)) {
m_length = length;
m_lengthWasSet = true;
return true;
}
return false;
}
bool SizesAttributeParser::parse(Vector<MediaQueryToken>& tokens)
{
if (tokens.isEmpty())
return false;
MediaQueryTokenIterator startToken = tokens.begin();
MediaQueryTokenIterator endToken;
// Split on a comma token, and send the result tokens to be parsed as (media-condition, length) pairs
for (MediaQueryTokenIterator token = tokens.begin(); token != tokens.end(); ++token) {
if (token->type() == CommaToken) {
endToken = token;
if (parseMediaConditionAndLength(startToken, endToken))
return true;
startToken = token;
++startToken;
}
}
endToken = tokens.end();
return parseMediaConditionAndLength(startToken, --endToken);
}
unsigned SizesAttributeParser::effectiveSize()
{
if (m_lengthWasSet)
return m_length;
return effectiveSizeDefaultValue();
}
unsigned SizesAttributeParser::effectiveSizeDefaultValue()
{
// Returning the equivalent of "100%"
return m_mediaValues->viewportWidth();
}
} // namespace
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