Make ResourceFetcher not to rely on MemoryCache to serve static data

third_party/WebKit/Source/core/fetch/ResourceFetcher.cpp

 /*
     Copyright (C) 1998 Lars Knoll (knoll@mpi-hd.mpg.de)
     Copyright (C) 2001 Dirk Mueller (mueller@kde.org)
     Copyright (C) 2002 Waldo Bastian (bastian@kde.org)
     Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011 Apple Inc. All rights reserved.
     Copyright (C) 2009 Torch Mobile Inc. http://www.torchmobile.com/
 
     This library is free software; you can redistribute it and/or
     modify it under the terms of the GNU Library General Public
     License as published by the Free Software Foundation; either
@@ skipping 285 matching lines @@
     m_validatedURLs.add(request.resourceRequest().url());
 }
 
 static PassOwnPtr<TracedValue> urlForTraceEvent(const KURL& url)
 {
     OwnPtr<TracedValue> value = TracedValue::create();
     value->setString("url", url.string());
     return value.release();
 }
 
-void ResourceFetcher::preCacheData(const FetchRequest& request, const ResourceFactory& factory, const SubstituteData& substituteData)
+PassRefPtrWillBeRawPtr<Resource> ResourceFetcher::resourceForStaticData(const FetchRequest& request, const ResourceFactory& factory, const SubstituteData& substituteData)
 {
     const KURL& url = request.resourceRequest().url();
     ASSERT(url.protocolIsData() || substituteData.isValid());
 
     // TODO(japhet): We only send main resource data: urls through WebURLLoader for the benefit of
     // a service worker test (RenderViewImplTest.ServiceWorkerNetworkProviderSetup), which is at a
     // layer where it isn't easy to mock out a network load. It uses data: urls to emulate the
     // behavior it wants to test, which would otherwise be reserved for network loads.
     if ((factory.type() == Resource::MainResource && !substituteData.isValid()) || factory.type() == Resource::Raw)
-        return;
+        return nullptr;
 
     const String cacheIdentifier = getCacheIdentifier();
     if (Resource* oldResource = memoryCache()->resourceForURL(url, cacheIdentifier)) {
         // There's no reason to re-parse if we saved the data from the previous parse.
         if (request.options().dataBufferingPolicy != DoNotBufferData)
-            return;
+            return oldResource;
         memoryCache()->remove(oldResource);
     }
 
     WebString mimetype;
     WebString charset;
     RefPtr<SharedBuffer> data;
     if (substituteData.isValid()) {
         mimetype = substituteData.mimeType();
         charset = substituteData.textEncoding();
         data = substituteData.content();
     } else {
         data = PassRefPtr<SharedBuffer>(Platform::current()->parseDataURL(url, mimetype, charset));
         if (!data)
-            return;
+            return nullptr;
     }
     ResourceResponse response(url, mimetype, data->size(), charset, String());
     response.setHTTPStatusCode(200);
     response.setHTTPStatusText("OK");
 
     RefPtrWillBeRawPtr<Resource> resource = factory.create(request.resourceRequest(), request.charset());
     resource->setNeedsSynchronousCacheHit(substituteData.forceSynchronousLoad());
     resource->setOptions(request.options());
     // FIXME: We should provide a body stream here.
     resource->responseReceived(response, nullptr);
     resource->setDataBufferingPolicy(BufferData);
     if (data->size())
         resource->setResourceBuffer(data);
     resource->setIdentifier(createUniqueIdentifier());
     resource->setCacheIdentifier(cacheIdentifier);
     resource->finish();
     memoryCache()->add(resource.get());
+    return resource.release();
 }
 
 void ResourceFetcher::moveCachedNonBlockingResourceToBlocking(Resource* resource, const FetchRequest& request)
 {
     // TODO(yoav): Test that non-blocking resources (video/audio/track) continue to not-block even after being preloaded and discovered.
     if (resource && resource->loader() && resource->isLoadEventBlockingResourceType() && resource->isLinkPreload() && !request.forPreload()) {
         if (m_nonBlockingLoaders)
             m_nonBlockingLoaders->remove(resource->loader());
         if (!m_loaders)
             m_loaders = ResourceLoaderSet::create();
@@ skipping 32 matching lines @@
 
         if (activityLogger) {
             Vector<String> argv;
             argv.append(Resource::resourceTypeToString(factory.type(), request.options().initiatorInfo));
             argv.append(url);
             activityLogger->logEvent("blinkRequestResource", argv.size(), argv.data());
         }
     }
 
     bool isStaticData = request.resourceRequest().url().protocolIsData() || substituteData.isValid();
+    RefPtrWillBeRawPtr<Resource> resource(nullptr);
     if (isStaticData)
-        preCacheData(request, factory, substituteData);
-    RefPtrWillBeRawPtr<Resource> resource = memoryCache()->resourceForURL(url, getCacheIdentifier());
+        resource = resourceForStaticData(request, factory, substituteData);
+    if (!resource)
+        resource = memoryCache()->resourceForURL(url, getCacheIdentifier());
 
     // See if we can use an existing resource from the cache. If so, we need to move it to be load blocking.
     moveCachedNonBlockingResourceToBlocking(resource.get(), request);
 
     const RevalidationPolicy policy = determineRevalidationPolicy(factory.type(), request, resource.get(), isStaticData);
 
     if (request.forPreload()) {
         DEFINE_RESOURCE_HISTOGRAM("Preload.");
     } else {
         DEFINE_RESOURCE_HISTOGRAM("");
@@ skipping 791 matching lines @@
     visitor->trace(m_loaders);
     visitor->trace(m_nonBlockingLoaders);
 #if ENABLE(OILPAN)
     visitor->trace(m_documentResources);
     visitor->trace(m_preloads);
     visitor->trace(m_resourceTimingInfoMap);
 #endif
 }
 
 } // namespace blink