ServiceWorker: Get registration info and its version attributes in one lock operation

content/child/service_worker/web_service_worker_provider_impl.cc

 // Copyright 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "content/child/service_worker/web_service_worker_provider_impl.h"
 
 #include "base/atomic_sequence_num.h"
 #include "base/logging.h"
 #include "content/child/child_thread.h"
 #include "content/child/service_worker/service_worker_dispatcher.h"
@@ skipping 31 matching lines @@
     return;
   }
 
   // TODO(kinuko): Here we could also register the current thread ID
   // on the provider context so that multiple WebServiceWorkerProviderImpl
   // (e.g. on document and on dedicated workers) can properly share
   // the single provider context across threads. (http://crbug.com/366538
   // for more context)
   GetDispatcher()->AddProviderClient(provider_id_, client);
 
-  if (!context_->registration()) {
-    // This provider is not associated with any registration.
+  if (!context_->IsAssociatedWithRegistration())

[Kunihiko Sakamoto, 2015/01/28 06:38:55]

I wonder if this and GetRegistrationInfoAndVersionAttributes() below should be
atomic as well?

[nhiroki, 2015/01/28 07:42:27]

Good point. Done.

     return;
-  }
 
   // Set .ready if the associated registration has the active service worker.
   if (context_->active_handle_id() != kInvalidServiceWorkerHandleId) {
+    ServiceWorkerRegistrationObjectInfo info;
+    ServiceWorkerVersionAttributes attrs;
+    context_->GetRegistrationInfoAndVersionAttributes(&info, &attrs);
+
     WebServiceWorkerRegistrationImpl* registration =
-        GetDispatcher()->FindServiceWorkerRegistration(
-            context_->registration()->info(), false);
+        GetDispatcher()->FindServiceWorkerRegistration(info, false);
     if (!registration) {
-      registration = GetDispatcher()->CreateServiceWorkerRegistration(
-          context_->registration()->info(), false);
-      ServiceWorkerVersionAttributes attrs = context_->GetVersionAttributes();
+      registration =
+          GetDispatcher()->CreateServiceWorkerRegistration(info, false);
       registration->SetInstalling(
           GetDispatcher()->GetServiceWorker(attrs.installing, false));
       registration->SetWaiting(
           GetDispatcher()->GetServiceWorker(attrs.waiting, false));
       registration->SetActive(
           GetDispatcher()->GetServiceWorker(attrs.active, false));
     }
     client->setReadyRegistration(registration);
   }
 
@@ skipping 33 matching lines @@
   if (dispatcher)
     dispatcher->RemoveProviderClient(provider_id_);
 }
 
 ServiceWorkerDispatcher* WebServiceWorkerProviderImpl::GetDispatcher() {
   return ServiceWorkerDispatcher::GetOrCreateThreadSpecificInstance(
       thread_safe_sender_.get());
 }
 
 }  // namespace content