HTML Imports: Teach preloader about HTML Imports.

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 88 matching lines @@
     RefPtrWillBeRawPtr<MediaQuerySet> mediaQueries = MediaQuerySet::createOffMainThread(attributeValue);
     MediaQueryEvaluator mediaQueryEvaluator("screen", mediaValues);
     return mediaQueryEvaluator.eval(mediaQueries.get());
 }
 
 class TokenPreloadScanner::StartTagScanner {
 public:
     StartTagScanner(const StringImpl* tagImpl, PassRefPtr<MediaValues> mediaValues)
         : m_tagImpl(tagImpl)
         , m_linkIsStyleSheet(false)
+        , m_linkIsImport(false)
         , m_matchedMediaAttribute(true)
         , m_inputIsImage(false)
         , m_imgSourceSize(0)
         , m_sourceSizeSet(false)
         , m_isCORSEnabled(false)
         , m_allowCredentials(DoNotAllowStoredCredentials)
         , m_mediaValues(mediaValues)
     {
         if (!match(m_tagImpl, imgTag)
             && !match(m_tagImpl, inputTag)
@@ skipping 67 matching lines @@
                 setUrlToLoad(bestFitSourceForImageAttributes(m_mediaValues->devicePixelRatio(), m_imgSourceSize, m_imgSrcUrl, m_srcsetImageCandidate), AllowURLReplacement);
             } else if (RuntimeEnabledFeatures::pictureSizesEnabled() && match(attributeName, sizesAttr) && !m_sourceSizeSet) {
                 m_imgSourceSize = SizesAttributeParser::findEffectiveSize(attributeValue, m_mediaValues);
                 m_sourceSizeSet = true;
                 if (!m_srcsetImageCandidate.isEmpty()) {
                     m_srcsetImageCandidate = bestFitSourceForSrcsetAttribute(m_mediaValues->devicePixelRatio(), m_imgSourceSize, m_imgSrcsetAttributeValue);
                     setUrlToLoad(bestFitSourceForImageAttributes(m_mediaValues->devicePixelRatio(), m_imgSourceSize, m_imgSrcUrl, m_srcsetImageCandidate), AllowURLReplacement);
                 }
             }
         } else if (match(m_tagImpl, linkTag)) {
-            if (match(attributeName, hrefAttr))
+            if (match(attributeName, hrefAttr)) {
                 setUrlToLoad(attributeValue, DisallowURLReplacement);
-            else if (match(attributeName, relAttr))
+            } else if (match(attributeName, relAttr)) {
                 m_linkIsStyleSheet = relAttributeIsStyleSheet(attributeValue);
-            else if (match(attributeName, mediaAttr))
+                m_linkIsImport = RuntimeEnabledFeatures::htmlImportsEnabled() && relAttributeIsImport(attributeValue);
+            } else if (match(attributeName, mediaAttr)) {
                 m_matchedMediaAttribute = mediaAttributeMatches(*m_mediaValues, attributeValue);
-            else if (match(attributeName, crossoriginAttr))
+            } 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);
         }
     }
 
+    static bool relAttributeWillBeImmediatelyUsed(const LinkRelAttribute& rel)
+    {
+        return !rel.isAlternate() && rel.iconType() == InvalidIcon && !rel.isDNSPrefetch();
+    }
+
     static bool relAttributeIsStyleSheet(const String& attributeValue)
     {
         LinkRelAttribute rel(attributeValue);
-        return rel.isStyleSheet() && !rel.isAlternate() && rel.iconType() == InvalidIcon && !rel.isDNSPrefetch();
+        return rel.isStyleSheet() && relAttributeWillBeImmediatelyUsed(rel);
+    }
+
+    static bool relAttributeIsImport(const String& attributeValue)
+    {
+        LinkRelAttribute rel(attributeValue);
+        return rel.isImport() && relAttributeWillBeImmediatelyUsed(rel);
     }
 
     void setUrlToLoad(const String& value, URLReplacement replacement)
     {
         // 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 (replacement == DisallowURLReplacement && !m_urlToLoad.isEmpty())
             return;
         String url = stripLeadingAndTrailingHTMLSpaces(value);
         if (url.isEmpty())
@@ skipping 10 matching lines @@
     }
 
     Resource::Type resourceType() const
     {
         if (match(m_tagImpl, scriptTag))
             return Resource::Script;
         if (match(m_tagImpl, imgTag) || (match(m_tagImpl, inputTag) && m_inputIsImage))
             return Resource::Image;
         if (match(m_tagImpl, linkTag) && m_linkIsStyleSheet)
             return Resource::CSSStyleSheet;
+        if (match(m_tagImpl, linkTag) && m_linkIsImport)
+            return Resource::ImportResource;
         ASSERT_NOT_REACHED();
         return Resource::Raw;
     }
 
     bool shouldPreload() const
     {
         if (m_urlToLoad.isEmpty())
             return false;
-        if (match(m_tagImpl, linkTag) && !m_linkIsStyleSheet)
+        if (match(m_tagImpl, linkTag) && !m_linkIsStyleSheet && !m_linkIsImport)
             return false;
         if (match(m_tagImpl, inputTag) && !m_inputIsImage)
             return false;
         return true;
     }
 
     bool isCORSEnabled() const
     {
         return m_isCORSEnabled;
     }
@@ skipping 10 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;
+    bool m_linkIsImport;
     bool m_matchedMediaAttribute;
     bool m_inputIsImage;
     String m_imgSrcUrl;
     String m_imgSrcsetAttributeValue;
     unsigned m_imgSourceSize;
     bool m_sourceSizeSet;
     bool m_isCORSEnabled;
     StoredCredentials m_allowCredentials;
     RefPtr<MediaValues> m_mediaValues;
 };
@@ skipping 134 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);
 }
 
 }