Webfont CORS-enabled fetching with fallback

Source/core/css/CSSFontFaceSrcValue.cpp

 /*
  * Copyright (C) 2007, 2010 Apple 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
@@ skipping 21 matching lines @@
 #include "core/dom/Node.h"
 #include "core/fetch/FetchRequest.h"
 #include "core/fetch/FontResource.h"
 #include "core/fetch/ResourceFetcher.h"
 #include "core/svg/SVGFontFaceElement.h"
 #include "platform/fonts/FontCustomPlatformData.h"
 #include "wtf/text/StringBuilder.h"
 
 namespace WebCore {
 
+CSSFontFaceSrcValue::FontResourceInvalidator::FontResourceInvalidator(CSSFontFaceSrcValue& srcValue)
+    : m_srcValue(srcValue)
+    , m_resource(srcValue.m_fetched)
+{
+    m_resource->addClient(this);

[Kunihiko Sakamoto, 2014/04/10 05:49:24]

Resource cancels in-flight request when all clients are removed.
https://code.google.com/p/chromium/codesearch#chromium/src/third_party/WebKit...

This change makes FontResource always have one client (invalidator), so
cancellation won't work for fonts.

Instead of using the invalidator, maybe we can just clear m_fetched in the
beginning of CSSFontFaceSrcValue::fetch() if m_corsFailed is true?

[bashi, 2014/04/10 07:05:51]

Great suggestion! Done.

+}
+
+CSSFontFaceSrcValue::FontResourceInvalidator::~FontResourceInvalidator()
+{
+    m_resource->removeClient(this);
+}
+
+void CSSFontFaceSrcValue::FontResourceInvalidator::fontLoaded(FontResource*)
+{
+    m_srcValue.m_invalidator.clear();
+}
+
+void CSSFontFaceSrcValue::FontResourceInvalidator::corsFailed(FontResource*)
+{
+    m_srcValue.m_fetched.clear();
+    m_srcValue.m_corsEnabled = NotCORSEnabled;
+    m_srcValue.m_invalidator.clear();
+}
+
 #if ENABLE(SVG_FONTS)
 bool CSSFontFaceSrcValue::isSVGFontFaceSrc() const
 {
     return equalIgnoringCase(m_format, "svg");
 }
 #endif
 
 bool CSSFontFaceSrcValue::isSupportedFormat() const
 {
     // Normally we would just check the format, but in order to avoid conflicts with the old WinIE style of font-face,
@@ skipping 29 matching lines @@
     return result.toString();
 }
 
 bool CSSFontFaceSrcValue::hasFailedOrCanceledSubresources() const
 {
     if (!m_fetched)
         return false;
     return m_fetched->loadFailedOrCanceled();
 }
 
+bool CSSFontFaceSrcValue::shouldSetCrossOriginAccessControl(const KURL& resource, SecurityOrigin* securityOrigin)
+{
+    if (m_corsEnabled == NotCORSEnabled || resource.isLocalFile() || resource.protocolIsData())
+        return false;
+    return !securityOrigin->canRequest(resource);
+}
+
 FontResource* CSSFontFaceSrcValue::fetch(Document* document)
 {
     if (!m_fetched) {
         FetchRequest request(ResourceRequest(document->completeURL(m_resource)), FetchInitiatorTypeNames::css);
+        SecurityOrigin* securityOrigin = document->securityOrigin();
+        if (shouldSetCrossOriginAccessControl(request.url(), securityOrigin)) {
+            request.setCrossOriginAccessControl(securityOrigin, DoNotAllowStoredCredentials);
+        }
         m_fetched = document->fetcher()->fetchFont(request);
+        m_invalidator = adoptPtr(new FontResourceInvalidator(*this));
     }
     return m_fetched.get();
 }
 
 bool CSSFontFaceSrcValue::equals(const CSSFontFaceSrcValue& other) const
 {
     return m_isLocal == other.m_isLocal && m_format == other.m_format && m_resource == other.m_resource;
 }
 
 }