Enable Media query evaluation in the preload scanner

Source/core/html/parser/HTMLPreloadScanner.cpp

 /*
  * 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.
@@ skipping 13 matching lines @@
  * (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 "core/html/parser/HTMLPreloadScanner.h"
 
 #include "HTMLNames.h"
 #include "InputTypeNames.h"
 #include "RuntimeEnabledFeatures.h"
+#include "core/css/MediaList.h"
+#include "core/css/MediaQueryEvaluator.h"
 #include "core/html/LinkRelAttribute.h"
 #include "core/html/parser/HTMLParserIdioms.h"
 #include "core/html/parser/HTMLSrcsetParser.h"
 #include "core/html/parser/HTMLTokenizer.h"
 #include "platform/TraceEvent.h"
 #include "wtf/MainThread.h"
 
 namespace WebCore {
 
 using namespace HTMLNames;
@@ skipping 39 matching lines @@
     if (match(tagImpl, inputTag))
         return inputTag.localName();
     if (match(tagImpl, linkTag))
         return linkTag.localName();
     if (match(tagImpl, scriptTag))
         return scriptTag.localName();
     ASSERT_NOT_REACHED();
     return emptyString();
 }
 
+static bool mediaAttributeMatches(const MediaValues* mediaValues, const String& attributeValue)
+{
+    RefPtr<MediaQuerySet> mediaQueries = MediaQuerySet::create(attributeValue);
+    MediaQueryEvaluator mediaQueryEvaluator("screen", mediaValues, false);
+    bool ret = mediaQueryEvaluator.eval(mediaQueries.get());
+    return ret;

[abarth-chromium, 2014/03/24 19:43:31]

I'd skip |ret| and just return the result of the function directly.

+}
+
 class TokenPreloadScanner::StartTagScanner {
 public:
-    StartTagScanner(const StringImpl* tagImpl, float deviceScaleFactor)
+    StartTagScanner(const StringImpl* tagImpl, float deviceScaleFactor, PassRefPtr<MediaValues> mediaValues)
         : m_tagImpl(tagImpl)
         , m_linkIsStyleSheet(false)
+        , m_mediaMatch(true)

[abarth-chromium, 2014/03/24 19:43:31]

We can probably come up with a slightly better name for this variable.  The
trick for boolean member variables is to read the follow sentence aloud:

"if <name-of-class> <name-of-bool-member>, ..."

If that makes sense, then we've got a good name.  Otherwise, there's room for
improvement.  For example,

"if the token preload scanner encountered img@src, ..."

         , m_inputIsImage(false)
         , m_deviceScaleFactor(deviceScaleFactor)
         , m_encounteredImgSrc(false)
         , m_isCORSEnabled(false)
         , m_allowCredentials(DoNotAllowStoredCredentials)
+        , m_mediaValues(mediaValues)
     {
         if (!match(m_tagImpl, imgTag)
             && !match(m_tagImpl, inputTag)
             && !match(m_tagImpl, linkTag)
             && !match(m_tagImpl, scriptTag))
             m_tagImpl = 0;
     }
 
     enum URLReplacement {
         AllowURLReplacement,
@@ skipping 15 matching lines @@
     void processAttributes(const Vector<CompactHTMLToken::Attribute>& attributes)
     {
         if (!m_tagImpl)
             return;
         for (Vector<CompactHTMLToken::Attribute>::const_iterator iter = attributes.begin(); iter != attributes.end(); ++iter)
             processAttribute(iter->name, iter->value);
     }
 
     PassOwnPtr<PreloadRequest> createPreloadRequest(const KURL& predictedBaseURL, const SegmentedString& source)
     {
-        if (!shouldPreload())
+        if (!shouldPreload() || !m_mediaMatch)
             return nullptr;
 
         TRACE_EVENT_INSTANT1("net", "PreloadRequest", "url", m_urlToLoad.ascii());
         TextPosition position = TextPosition(source.currentLine(), source.currentColumn());
-        OwnPtr<PreloadRequest> request = PreloadRequest::create(initiatorFor(m_tagImpl), position, m_urlToLoad, predictedBaseURL, resourceType(), m_mediaAttribute);
+        OwnPtr<PreloadRequest> request = PreloadRequest::create(initiatorFor(m_tagImpl), position, m_urlToLoad, predictedBaseURL, resourceType());
         if (isCORSEnabled())
             request->setCrossOriginEnabled(allowStoredCredentials());
         request->setCharset(charset());
         return request.release();
     }
 
 private:
+

[abarth-chromium, 2014/03/24 19:43:31]

This change looks spurious

     template<typename NameType>
     void processAttribute(const NameType& attributeName, const String& attributeValue)
     {
         if (match(attributeName, charsetAttr))
             m_charset = attributeValue;
 
         if (match(m_tagImpl, scriptTag)) {
             if (match(attributeName, srcAttr))
                 setUrlToLoad(attributeValue, DisallowURLReplacement);
             else if (match(attributeName, crossoriginAttr))
                 setCrossOriginAllowed(attributeValue);
         } else if (match(m_tagImpl, imgTag)) {
             if (match(attributeName, srcAttr) && !m_encounteredImgSrc) {
                 m_encounteredImgSrc = true;
                 setUrlToLoad(bestFitSourceForImageAttributes(m_deviceScaleFactor, attributeValue, m_srcsetImageCandidate), AllowURLReplacement);
             } else if (match(attributeName, crossoriginAttr)) {
                 setCrossOriginAllowed(attributeValue);
             } else if (RuntimeEnabledFeatures::srcsetEnabled()
                 && match(attributeName, srcsetAttr)
                 && m_srcsetImageCandidate.isEmpty()) {
                 m_srcsetImageCandidate = bestFitSourceForSrcsetAttribute(m_deviceScaleFactor, attributeValue);
                 setUrlToLoad(bestFitSourceForImageAttributes(m_deviceScaleFactor, m_urlToLoad, m_srcsetImageCandidate), AllowURLReplacement);
             }
         } else if (match(m_tagImpl, linkTag)) {
             if (match(attributeName, hrefAttr))
                 setUrlToLoad(attributeValue, DisallowURLReplacement);
             else if (match(attributeName, relAttr))
                 m_linkIsStyleSheet = relAttributeIsStyleSheet(attributeValue);
             else if (match(attributeName, mediaAttr))
-                m_mediaAttribute = attributeValue;
+                m_mediaMatch = mediaAttributeMatches(m_mediaValues.get(), attributeValue);
             else if (match(attributeName, crossoriginAttr))
                 setCrossOriginAllowed(attributeValue);
         } else if (match(m_tagImpl, inputTag)) {
             if (match(attributeName, srcAttr))
                 setUrlToLoad(attributeValue, DisallowURLReplacement);
             else if (match(attributeName, typeAttr))
                 m_inputIsImage = equalIgnoringCase(attributeValue, InputTypeNames::image);
         }
     }
 
@@ skipping 63 matching lines @@
             m_allowCredentials = AllowStoredCredentials;
         else
             m_allowCredentials = DoNotAllowStoredCredentials;
     }
 
     const StringImpl* m_tagImpl;
     String m_urlToLoad;
     ImageCandidate m_srcsetImageCandidate;
     String m_charset;
     bool m_linkIsStyleSheet;
-    String m_mediaAttribute;
+    bool m_mediaMatch;
     bool m_inputIsImage;
     float m_deviceScaleFactor;
     bool m_encounteredImgSrc;
     bool m_isCORSEnabled;
     StoredCredentials m_allowCredentials;
+    RefPtr<MediaValues> m_mediaValues;
 };
 
-TokenPreloadScanner::TokenPreloadScanner(const KURL& documentURL, float deviceScaleFactor)
+TokenPreloadScanner::TokenPreloadScanner(const KURL& documentURL, float deviceScaleFactor, PassRefPtr<MediaValues> mediaValues)
     : m_documentURL(documentURL)
     , m_inStyle(false)
     , m_deviceScaleFactor(deviceScaleFactor)
     , m_templateCount(0)
+    , m_mediaValues(mediaValues)
 {
 }
 
 TokenPreloadScanner::~TokenPreloadScanner()
 {
 }
 
 TokenPreloadScannerCheckpoint TokenPreloadScanner::createCheckpoint()
 {
     TokenPreloadScannerCheckpoint checkpoint = m_checkpoints.size();
     m_checkpoints.append(Checkpoint(m_predictedBaseElementURL, m_inStyle, m_templateCount));
     return checkpoint;
 }
 
+

[abarth-chromium, 2014/03/24 19:43:31]

ditto

 void TokenPreloadScanner::rewindTo(TokenPreloadScannerCheckpoint checkpointIndex)
 {
     ASSERT(checkpointIndex < m_checkpoints.size()); // If this ASSERT fires, checkpointIndex is invalid.
     const Checkpoint& checkpoint = m_checkpoints[checkpointIndex];
     m_predictedBaseElementURL = checkpoint.predictedBaseElementURL;
     m_inStyle = checkpoint.inStyle;
     m_templateCount = checkpoint.templateCount;
     m_cssScanner.reset();
     m_checkpoints.clear();
 }
@@ skipping 45 matching lines @@
             return;
         }
         if (match(tagImpl, baseTag)) {
             // The first <base> element is the one that wins.
             if (!m_predictedBaseElementURL.isEmpty())
                 return;
             updatePredictedBaseURL(token);
             return;
         }
 
-        StartTagScanner scanner(tagImpl, m_deviceScaleFactor);
+        StartTagScanner scanner(tagImpl, m_deviceScaleFactor, m_mediaValues);
         scanner.processAttributes(token.attributes());
         OwnPtr<PreloadRequest> request = scanner.createPreloadRequest(m_predictedBaseElementURL, source);
         if (request)
             requests.append(request.release());
         return;
     }
     default: {
         return;
     }
     }
 }
 
 template<typename Token>
 void TokenPreloadScanner::updatePredictedBaseURL(const Token& token)
 {
     ASSERT(m_predictedBaseElementURL.isEmpty());
     if (const typename Token::Attribute* hrefAttribute = token.getAttributeItem(hrefAttr))
         m_predictedBaseElementURL = KURL(m_documentURL, stripLeadingAndTrailingHTMLSpaces(hrefAttribute->value)).copy();
 }
 
-HTMLPreloadScanner::HTMLPreloadScanner(const HTMLParserOptions& options, const KURL& documentURL, float deviceScaleFactor)
-    : m_scanner(documentURL, deviceScaleFactor)
+HTMLPreloadScanner::HTMLPreloadScanner(const HTMLParserOptions& options, const KURL& documentURL, float deviceScaleFactor, PassRefPtr<MediaValues> mediaValues)
+    : m_scanner(documentURL, deviceScaleFactor, mediaValues)
     , m_tokenizer(HTMLTokenizer::create(options))
 {
 }
 
 HTMLPreloadScanner::~HTMLPreloadScanner()
 {
 }
 
 void HTMLPreloadScanner::appendToEnd(const SegmentedString& source)
 {
@@ skipping 14 matching lines @@
         if (m_token.type() == HTMLToken::StartTag)
             m_tokenizer->updateStateFor(attemptStaticStringCreation(m_token.name(), Likely8Bit));
         m_scanner.scan(m_token, m_source, requests);
         m_token.clear();
     }
 
     preloader->takeAndPreload(requests);
 }
 
 }