Add <link rel=preconnect> support to the HTMLPreloadScanner

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 93 matching lines @@
     RefPtrWillBeRawPtr<MediaQuerySet> mediaQueries = MediaQuerySet::createOffMainThread(attributeValue);
     MediaQueryEvaluator mediaQueryEvaluator(mediaValues);
     return mediaQueryEvaluator.eval(mediaQueries.get());
 }
 
 class TokenPreloadScanner::StartTagScanner {
 public:
     StartTagScanner(const StringImpl* tagImpl, PassRefPtr<MediaValues> mediaValues)
         : m_tagImpl(tagImpl)
         , m_linkIsStyleSheet(false)
+        , m_linkIsPreconnect(false)
         , m_matchedMediaAttribute(true)
         , m_inputIsImage(false)
         , m_sourceSize(0)
         , m_sourceSizeSet(false)
         , m_isCORSEnabled(false)
         , m_defer(FetchRequest::NoDefer)
         , m_allowCredentials(DoNotAllowStoredCredentials)
         , m_mediaValues(mediaValues)
     {
         ASSERT(m_mediaValues->isCached());
@@ skipping 35 matching lines @@
     }
 
     void handlePictureSourceURL(String& sourceURL)
     {
         if (match(m_tagImpl, sourceTag) && m_matchedMediaAttribute && sourceURL.isEmpty())
             sourceURL = m_srcsetImageCandidate.toString();
         else if (match(m_tagImpl, imgTag) && !sourceURL.isEmpty())
             setUrlToLoad(sourceURL, AllowURLReplacement);
     }
 
-    PassOwnPtr<PreloadRequest> createPreloadRequest(const KURL& predictedBaseURL, const SegmentedString& source, const ClientHintsPreferences& clientHintsPreferences)
+    void preconnectHost(PreconnecterHost* preconnecter, KURL baseURL)
     {
+        KURL host(baseURL, m_urlToLoad);
+        if (!host.isValid())
+            return;
+        // TODO(yoav): Add a real cross attribute value here once it's no longer a no-op.

[Mike West, 2015/06/02 11:18:33]

I see. Ok, yes, please add this TODO to the test as well so that it's clear that
the current behavior isn't final.

+        preconnecter->preconnect(host, CrossOriginAttributeNotSet);
+    }
+
+    PassOwnPtr<PreloadRequest> createPreloadRequest(const KURL& predictedBaseURL, const SegmentedString& source, const ClientHintsPreferences& clientHintsPreferences, PreconnecterHost* preconnecter)
+    {
+        if (shouldPreconnect()) {
+            preconnectHost(preconnecter, predictedBaseURL);
+            return nullptr;
+        }
         if (!shouldPreload() || !m_matchedMediaAttribute)
             return nullptr;
 
         TextPosition position = TextPosition(source.currentLine(), source.currentColumn());
         FetchRequest::ResourceWidth resourceWidth;
         if (m_sourceSizeSet && m_srcsetImageCandidate.resourceWidth() != UninitializedDescriptor) {
             resourceWidth.width = m_sourceSize;
             resourceWidth.isSet = true;
         }
         OwnPtr<PreloadRequest> request = PreloadRequest::create(initiatorFor(m_tagImpl), position, m_urlToLoad, predictedBaseURL, resourceType(), resourceWidth, clientHintsPreferences);
@@ skipping 41 matching lines @@
         }
     }
 
     template<typename NameType>
     void processLinkAttribute(const NameType& attributeName, const String& attributeValue)
     {
         // FIXME - Don't set rel/media/crossorigin multiple times.
         if (match(attributeName, hrefAttr))
             setUrlToLoad(attributeValue, DisallowURLReplacement);
         else if (match(attributeName, relAttr))
-            m_linkIsStyleSheet = relAttributeIsStyleSheet(attributeValue);
+            checkRelAttribute(attributeValue, m_linkIsStyleSheet, m_linkIsPreconnect);
         else if (match(attributeName, mediaAttr))
             m_matchedMediaAttribute = mediaAttributeMatches(*m_mediaValues, attributeValue);
         else if (match(attributeName, crossoriginAttr))
             setCrossOriginAllowed(attributeValue);
     }
 
     template<typename NameType>
     void processInputAttribute(const NameType& attributeName, const String& attributeValue)
     {
         // FIXME - Don't set type multiple times.
@@ skipping 41 matching lines @@
         else if (match(m_tagImpl, linkTag))
             processLinkAttribute(attributeName, attributeValue);
         else if (match(m_tagImpl, inputTag))
             processInputAttribute(attributeName, attributeValue);
         else if (match(m_tagImpl, sourceTag))
             processSourceAttribute(attributeName, attributeValue);
         else if (match(m_tagImpl, videoTag))
             processVideoAttribute(attributeName, attributeValue);
     }
 
-    static bool relAttributeIsStyleSheet(const String& attributeValue)
+    static void checkRelAttribute(const String& attributeValue, bool& isStyleSheet, bool& isPreconnect)
     {
         LinkRelAttribute rel(attributeValue);
-        return rel.isStyleSheet() && !rel.isAlternate() && rel.iconType() == InvalidIcon && !rel.isDNSPrefetch();
+        isStyleSheet = rel.isStyleSheet() && !rel.isAlternate() && rel.iconType() == InvalidIcon && !rel.isDNSPrefetch();

[Mike West, 2015/06/02 11:18:33]

Is this used anywhere else? I'd rather see it inlined into line 246 rather than
doing the param-passing here.

+        isPreconnect = rel.isPreconnect();
     }
 
     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 14 matching lines @@
         if (match(m_tagImpl, scriptTag))
             return Resource::Script;
         if (match(m_tagImpl, imgTag) || match(m_tagImpl, videoTag) || (match(m_tagImpl, inputTag) && m_inputIsImage))
             return Resource::Image;
         if (match(m_tagImpl, linkTag) && m_linkIsStyleSheet)
             return Resource::CSSStyleSheet;
         ASSERT_NOT_REACHED();
         return Resource::Raw;
     }
 
+    bool shouldPreconnect() const
+    {
+        return (match(m_tagImpl, linkTag) && m_linkIsPreconnect && !m_urlToLoad.isEmpty());

[Mike West, 2015/06/02 11:18:33]

Nit: Drop the outer ().

+    }
+
     bool shouldPreload() const
     {
         if (m_urlToLoad.isEmpty())
             return false;
         if (match(m_tagImpl, linkTag) && !m_linkIsStyleSheet)
             return false;
         if (match(m_tagImpl, inputTag) && !m_inputIsImage)
             return false;
         return true;
     }
@@ skipping 25 matching lines @@
     bool defer() const
     {
         return m_defer;
     }
 
     const StringImpl* m_tagImpl;
     String m_urlToLoad;
     ImageCandidate m_srcsetImageCandidate;
     String m_charset;
     bool m_linkIsStyleSheet;
+    bool m_linkIsPreconnect;
     bool m_matchedMediaAttribute;
     bool m_inputIsImage;
     String m_imgSrcUrl;
     String m_srcsetAttributeValue;
     float m_sourceSize;
     bool m_sourceSizeSet;
     bool m_isCORSEnabled;
     FetchRequest::DeferOption m_defer;
     StoredCredentials m_allowCredentials;
     RefPtr<MediaValues> m_mediaValues;
 };
 
-TokenPreloadScanner::TokenPreloadScanner(const KURL& documentURL, PassOwnPtr<CachedDocumentParameters> documentParameters)
+TokenPreloadScanner::TokenPreloadScanner(const KURL& documentURL, PassOwnPtr<CachedDocumentParameters> documentParameters, PassOwnPtr<PreconnecterHost> preconnecter)
     : m_documentURL(documentURL)
     , m_inStyle(false)
     , m_inPicture(false)
     , m_isAppCacheEnabled(false)
     , m_isCSPEnabled(false)
     , m_templateCount(0)
     , m_documentParameters(documentParameters)
+    , m_preconnecter(preconnecter)
 {
     ASSERT(m_documentParameters.get());
     ASSERT(m_documentParameters->mediaValues.get());
     ASSERT(m_documentParameters->mediaValues->isCached());
 }
 
 TokenPreloadScanner::~TokenPreloadScanner()
 {
 }
 
@@ skipping 120 matching lines @@
         if (match(tagImpl, pictureTag)) {
             m_inPicture = true;
             m_pictureSourceURL = String();
             return;
         }
 
         StartTagScanner scanner(tagImpl, m_documentParameters->mediaValues);
         scanner.processAttributes(token.attributes());
         if (m_inPicture)
             scanner.handlePictureSourceURL(m_pictureSourceURL);
-        OwnPtr<PreloadRequest> request = scanner.createPreloadRequest(m_predictedBaseElementURL, source, m_clientHintsPreferences);
+        OwnPtr<PreloadRequest> request = scanner.createPreloadRequest(m_predictedBaseElementURL, source, m_clientHintsPreferences, m_preconnecter.get());
         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)) {
         KURL url(m_documentURL, stripLeadingAndTrailingHTMLSpaces(hrefAttribute->value));
         m_predictedBaseElementURL = url.isValid() ? url.copy() : KURL();
     }
 }
 
-HTMLPreloadScanner::HTMLPreloadScanner(const HTMLParserOptions& options, const KURL& documentURL, PassOwnPtr<CachedDocumentParameters> documentParameters)
-    : m_scanner(documentURL, documentParameters)
+HTMLPreloadScanner::HTMLPreloadScanner(const HTMLParserOptions& options, const KURL& documentURL, PassOwnPtr<CachedDocumentParameters> documentParameters, PassOwnPtr<PreconnecterHost> preconnecter)
+    : m_scanner(documentURL, documentParameters, preconnecter)
     , m_tokenizer(HTMLTokenizer::create(options))
 {
 }
 
 HTMLPreloadScanner::~HTMLPreloadScanner()
 {
 }
 
 void HTMLPreloadScanner::appendToEnd(const SegmentedString& source)
 {
@@ skipping 30 matching lines @@
         mediaValues = givenMediaValues;
     else
         mediaValues = MediaValuesCached::create(*document);
     ASSERT(mediaValues->isSafeToSendToAnotherThread());
     defaultViewportMinWidth = document->viewportDefaultMinWidth();
     viewportMetaZeroValuesQuirk = document->settings() && document->settings()->viewportMetaZeroValuesQuirk();
     viewportMetaEnabled = document->settings() && document->settings()->viewportMetaEnabled();
 }
 
 }