[WIP] WebFonts cache-aware timeout adaption

third_party/WebKit/Source/core/fetch/Resource.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) 2006 Samuel Weinig (sam.weinig@gmail.com)
     Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011 Apple Inc. All rights reserved.
 
     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 294 matching lines @@
       m_preloadCount(0),
       m_preloadDiscoveryTime(0.0),
       m_cacheIdentifier(MemoryCache::defaultCacheIdentifier()),
       m_preloadResult(PreloadNotReferenced),
       m_type(type),
       m_status(NotStarted),
       m_needsSynchronousCacheHit(false),
       m_linkPreload(false),
       m_isRevalidating(false),
       m_isAlive(false),
+      m_isAddRemoveClientProhibited(false),
       m_options(options),
       m_responseTimestamp(currentTime()),
       m_cancelTimer(this, &Resource::cancelTimerFired),
       m_resourceRequest(request) {
   DCHECK_EQ(
       m_type,
       unsigned(
           type));  // m_type is a bitfield, so this tests careless updates of the enum.
   InstanceCounters::incrementCounter(InstanceCounters::ResourceCounter);
 
@@ skipping 84 matching lines @@
   if (!errorOccurred())
     setStatus(LoadError);
   DCHECK(errorOccurred());
   m_data.clear();
   m_loader = nullptr;
   checkNotify();
 }
 
 void Resource::finish(double loadFinishTime) {
   DCHECK(!m_isRevalidating);
+  if (m_resourceRequest.isCacheAwareLoadingActivated())

[hiroshige, 2016/10/05 08:27:10]

I'd like to prevent Resource from participating state control for cache-aware
loading.
The cache-aware loading should be managed only by ResourceFetcher and
ResourceLoader, and Resource and ResourceClient should just receive
notifications. By doing so, cache-aware loading doesn't complicate Resource
state management.

isCacheAwareLoadingActivated() looks like a state of current ongoing resource
loading, not of Resource.
Probably we can move this flag to ResourceLoader.

[Shao-Chuan Lee, 2016/10/07 08:10:06]

Moved manipulation logic to ResourceFetcher.
Still keeping the Activated flag in ResourceRequest since it cannot (shouldn't)
be modified in ResourceLoader methods.

+    m_resourceRequest.deactivateCacheAwareLoading();
   m_loadFinishTime = loadFinishTime;
   if (!errorOccurred())
     m_status = Cached;
   m_loader = nullptr;
   checkNotify();
 }
 
 AtomicString Resource::httpContentType() const {
   return extractMIMETypeFromMediaType(
       m_response.httpHeaderField(HTTPNames::Content_Type).lower());
@@ skipping 116 matching lines @@
   DCHECK(!request.isNull());
   m_isRevalidating = true;
   m_resourceRequest = request;
   m_status = NotStarted;
 }
 
 void Resource::willFollowRedirect(ResourceRequest& newRequest,
                                   const ResourceResponse& redirectResponse) {
   if (m_isRevalidating)
     revalidationFailed();
+  if (m_resourceRequest.isCacheAwareLoadingActivated())
+    m_resourceRequest.deactivateCacheAwareLoading();
   m_redirectChain.append(RedirectPair(newRequest, redirectResponse));
 }
 
 void Resource::setResponse(const ResourceResponse& response) {
   m_response = response;
   if (m_response.wasFetchedViaServiceWorker())
     m_cacheHandler = ServiceWorkerResponseCachedMetadataHandler::create(
         this, m_fetcherSecurityOrigin.get());
 }
 
@@ skipping 114 matching lines @@
     }
   }
   if (!hasClientsOrObservers()) {
     m_isAlive = true;
     memoryCache()->makeLive(this);
   }
 }
 
 void Resource::addClient(ResourceClient* client,
                          PreloadReferencePolicy policy) {
+  DCHECK(!m_isAddRemoveClientProhibited);
+
   willAddClientOrObserver(policy);
 
   if (m_isRevalidating) {
     m_clients.add(client);
     return;
   }
 
   // If we have existing data to send to the new client and the resource type supprts it, send it asynchronously.
   if (!m_response.isNull() &&
       !shouldSendCachedDataSynchronouslyForType(getType()) &&
       !m_needsSynchronousCacheHit) {
     m_clientsAwaitingCallback.add(client);
     ResourceCallback::callbackHandler().schedule(this);
     return;
   }
 
   m_clients.add(client);
   didAddClient(client);
   return;
 }
 
 void Resource::removeClient(ResourceClient* client) {
+  DCHECK(!m_isAddRemoveClientProhibited);
+
   // This code may be called in a pre-finalizer, where weak members in the
   // HashCountedSet are already swept out.
 
   if (m_finishedClients.contains(client))
     m_finishedClients.remove(client);
   else if (m_clientsAwaitingCallback.contains(client))
     m_clientsAwaitingCallback.remove(client);
   else
     m_clients.remove(client);
 
@@ skipping 346 matching lines @@
     case Resource::LinkPrefetch:
     case Resource::TextTrack:
     case Resource::Media:
     case Resource::Manifest:
       return false;
   }
   NOTREACHED();
   return false;
 }
 
+void Resource::willReloadAfterDiskCacheMiss() {
+  m_resourceRequest.deactivateCacheAwareLoading();
+
+  DCHECK(!m_isAddRemoveClientProhibited);
+  m_isAddRemoveClientProhibited = true;
+  ResourceClientWalker<ResourceClient> w(m_clients);
+  while (ResourceClient* c = w.next()) {

[Takashi Toyoshima, 2016/10/05 07:06:18]

nit: we do not use {} for one-liner.

[Shao-Chuan Lee, 2016/10/05 10:16:10]

Done.

+    c->willReloadAfterDiskCacheMiss(this);
+  }
+  m_isAddRemoveClientProhibited = false;
+}
+
 }  // namespace blink