Use SizesAttributeParser to get the right srcset resource

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 16 matching lines @@
 
 #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/css/MediaValues.h"
+#include "core/css/parser/SizesAttributeParser.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 53 matching lines @@
     return mediaQueryEvaluator.eval(mediaQueries.get());
 }
 
 class TokenPreloadScanner::StartTagScanner {
 public:
     StartTagScanner(const StringImpl* tagImpl, PassRefPtr<MediaValues> mediaValues)
         : m_tagImpl(tagImpl)
         , m_linkIsStyleSheet(false)
         , m_matchedMediaAttribute(true)
         , m_inputIsImage(false)
-        , m_encounteredImgSrc(false)
+        , m_imgSourceSize(0)
         , 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;
+        if (RuntimeEnabledFeatures::pictureSizesEnabled())
+            m_imgSourceSize = SizesAttributeParser::findEffectiveSize(String(), m_mediaValues);
     }
 
     enum URLReplacement {
         AllowURLReplacement,
         DisallowURLReplacement
     };
 
     void processAttributes(const HTMLToken::AttributeList& attributes)
     {
         ASSERT(isMainThread());
@@ skipping 34 matching lines @@
     {
         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)) {
-            int effectiveSize = -1; // FIXME - hook up the real value from `sizes`
-            if (match(attributeName, srcAttr) && !m_encounteredImgSrc) {
-                m_encounteredImgSrc = true;
-                setUrlToLoad(bestFitSourceForImageAttributes(m_mediaValues->devicePixelRatio(), effectiveSize, attributeValue, m_srcsetImageCandidate), AllowURLReplacement);
+            if (match(attributeName, srcAttr) && m_imgSrcUrl.isNull()) {
+                m_imgSrcUrl = attributeValue;
+                setUrlToLoad(bestFitSourceForImageAttributes(m_mediaValues->devicePixelRatio(), m_imgSourceSize, attributeValue, m_srcsetImageCandidate), AllowURLReplacement);
             } else if (match(attributeName, crossoriginAttr)) {
                 setCrossOriginAllowed(attributeValue);
             } else if (match(attributeName, srcsetAttr) && m_srcsetImageCandidate.isEmpty()) {
-                m_srcsetImageCandidate = bestFitSourceForSrcsetAttribute(m_mediaValues->devicePixelRatio(), effectiveSize, attributeValue);
-                setUrlToLoad(bestFitSourceForImageAttributes(m_mediaValues->devicePixelRatio(), effectiveSize, m_urlToLoad, m_srcsetImageCandidate), AllowURLReplacement);
+                m_srcsetImageCandidate = bestFitSourceForSrcsetAttribute(m_mediaValues->devicePixelRatio(), m_imgSourceSize, attributeValue);
+                setUrlToLoad(bestFitSourceForImageAttributes(m_mediaValues->devicePixelRatio(), m_imgSourceSize, m_imgSrcUrl, m_srcsetImageCandidate), AllowURLReplacement);
+            } else if (RuntimeEnabledFeatures::pictureSizesEnabled() && match(attributeName, sizesAttr) && m_imgSourceSize < 0) {

[eseidel, 2014/04/19 04:18:46]

it's unsigned < 0 is impossible.

+                m_imgSourceSize = SizesAttributeParser::findEffectiveSize(attributeValue, m_mediaValues);
+                if (!m_srcsetImageCandidate.isEmpty())
+                    setUrlToLoad(bestFitSourceForImageAttributes(m_mediaValues->devicePixelRatio(), m_imgSourceSize, m_imgSrcUrl, 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_matchedMediaAttribute = mediaAttributeMatches(*m_mediaValues, attributeValue);
             else if (match(attributeName, crossoriginAttr))
                 setCrossOriginAllowed(attributeValue);
@@ skipping 73 matching lines @@
             m_allowCredentials = DoNotAllowStoredCredentials;
     }
 
     const StringImpl* m_tagImpl;
     String m_urlToLoad;
     ImageCandidate m_srcsetImageCandidate;
     String m_charset;
     bool m_linkIsStyleSheet;
     bool m_matchedMediaAttribute;
     bool m_inputIsImage;
-    bool m_encounteredImgSrc;
+    String m_imgSrcUrl;
+    unsigned m_imgSourceSize;
     bool m_isCORSEnabled;
     StoredCredentials m_allowCredentials;
     RefPtr<MediaValues> m_mediaValues;
 };
 
 TokenPreloadScanner::TokenPreloadScanner(const KURL& documentURL, PassRefPtr<MediaValues> mediaValues)
     : m_documentURL(documentURL)
     , m_inStyle(false)
     , m_templateCount(0)
     , m_mediaValues(mediaValues)
@@ skipping 128 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);
 }
 
 }