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/*
* Copyright (C) 2008 Apple Inc. All Rights Reserved.
* Copyright (C) 2009 Torch Mobile, Inc. http://www.torchmobile.com/
* Copyright (C) 2010 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.
*/
#include "config.h"
#include "HTMLPreloadScanner.h"
#include "CachedResourceLoader.h"
#include "Document.h"
#include "InputType.h"
#include "HTMLDocumentParser.h"
#include "HTMLTokenizer.h"
#include "HTMLLinkElement.h"
#include "HTMLNames.h"
#include "HTMLParserIdioms.h"
#include "MediaList.h"
#include "MediaQueryEvaluator.h"
namespace WebCore {
using namespace HTMLNames;
namespace {
class PreloadTask {
public:
PreloadTask(const HTMLToken& token)
: m_tagName(token.name().data(), token.name().size())
, m_linkIsStyleSheet(false)
, m_linkMediaAttributeIsScreen(true)
, m_inputIsImage(false)
{
processAttributes(token.attributes());
}
void processAttributes(const HTMLToken::AttributeList& attributes)
{
if (m_tagName != imgTag
&& m_tagName != inputTag
&& m_tagName != linkTag
&& m_tagName != scriptTag)
return;
for (HTMLToken::AttributeList::const_iterator iter = attributes.begin();
iter != attributes.end(); ++iter) {
AtomicString attributeName(iter->m_name.data(), iter->m_name.size());
String attributeValue(iter->m_value.data(), iter->m_value.size());
if (attributeName == charsetAttr)
m_charset = attributeValue;
if (m_tagName == scriptTag || m_tagName == imgTag) {
if (attributeName == srcAttr)
setUrlToLoad(attributeValue);
} else if (m_tagName == linkTag) {
if (attributeName == hrefAttr)
setUrlToLoad(attributeValue);
else if (attributeName == relAttr)
m_linkIsStyleSheet = relAttributeIsStyleSheet(attributeValue);
else if (attributeName == mediaAttr)
m_linkMediaAttributeIsScreen = linkMediaAttributeIsScreen(attributeValue);
} else if (m_tagName == inputTag) {
if (attributeName == srcAttr)
setUrlToLoad(attributeValue);
else if (attributeName == typeAttr)
m_inputIsImage = equalIgnoringCase(attributeValue, InputTypeNames::image());
}
}
}
static bool relAttributeIsStyleSheet(const String& attributeValue)
{
HTMLLinkElement::RelAttribute rel;
HTMLLinkElement::tokenizeRelAttribute(attributeValue, rel);
return rel.m_isStyleSheet && !rel.m_isAlternate && !rel.m_isIcon && !rel.m_isDNSPrefetch;
}
static bool linkMediaAttributeIsScreen(const String& attributeValue)
{
if (attributeValue.isEmpty())
return true;
RefPtr<MediaList> mediaList = MediaList::createAllowingDescriptionSyntax(attributeValue);
// Only preload screen media stylesheets. Used this way, the evaluator evaluates to true for any
// rules containing complex queries (full evaluation is possible but it requires a frame and a style selector which
// may be problematic here).
MediaQueryEvaluator mediaQueryEvaluator("screen");
return mediaQueryEvaluator.eval(mediaList.get());
}
void setUrlToLoad(const String& attributeValue)
{
// We only respect the first src/href, per HTML5:
// http://www.whatwg.org/specs/web-apps/current-work/multipage/tokenization.html#attribute-name-state
if (!m_urlToLoad.isEmpty())
return;
m_urlToLoad = stripLeadingAndTrailingHTMLSpaces(attributeValue);
}
void preload(Document* document, bool scanningBody)
{
if (m_urlToLoad.isEmpty())
return;
CachedResourceLoader* cachedResourceLoader = document->cachedResourceLoader();
ResourceRequest request = document->completeURL(m_urlToLoad);
if (m_tagName == scriptTag)
cachedResourceLoader->preload(CachedResource::Script, request, m_charset, scanningBody);
else if (m_tagName == imgTag || (m_tagName == inputTag && m_inputIsImage))
cachedResourceLoader->preload(CachedResource::ImageResource, request, String(), scanningBody);
else if (m_tagName == linkTag && m_linkIsStyleSheet && m_linkMediaAttributeIsScreen)
cachedResourceLoader->preload(CachedResource::CSSStyleSheet, request, m_charset, scanningBody);
}
const AtomicString& tagName() const { return m_tagName; }
private:
AtomicString m_tagName;
String m_urlToLoad;
String m_charset;
bool m_linkIsStyleSheet;
bool m_linkMediaAttributeIsScreen;
bool m_inputIsImage;
};
} // namespace
HTMLPreloadScanner::HTMLPreloadScanner(Document* document)
: m_document(document)
, m_cssScanner(document)
, m_tokenizer(HTMLTokenizer::create(HTMLDocumentParser::usePreHTML5ParserQuirks(document)))
, m_bodySeen(false)
, m_inStyle(false)
{
}
void HTMLPreloadScanner::appendToEnd(const SegmentedString& source)
{
m_source.append(source);
}
void HTMLPreloadScanner::scan()
{
// FIXME: We should save and re-use these tokens in HTMLDocumentParser if
// the pending script doesn't end up calling document.write.
while (m_tokenizer->nextToken(m_source, m_token)) {
processToken();
m_token.clear();
}
}
void HTMLPreloadScanner::processToken()
{
if (m_inStyle) {
if (m_token.type() == HTMLToken::Character)
m_cssScanner.scan(m_token, scanningBody());
else if (m_token.type() == HTMLToken::EndTag) {
m_inStyle = false;
m_cssScanner.reset();
}
}
if (m_token.type() != HTMLToken::StartTag)
return;
PreloadTask task(m_token);
m_tokenizer->updateStateFor(task.tagName(), m_document->frame());
if (task.tagName() == bodyTag)
m_bodySeen = true;
if (task.tagName() == styleTag)
m_inStyle = true;
task.preload(m_document, scanningBody());
}
bool HTMLPreloadScanner::scanningBody() const
{
return m_document->body() || m_bodySeen;
}
}
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