Add AffiliatedInvalidationServiceProvider

chrome/browser/chromeos/policy/affiliated_invalidation_service_provider.h

+// Copyright 2015 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.
+
+#ifndef CHROME_BROWSER_CHROMEOS_POLICY_AFFILIATED_INVALIDATION_SERVICE_PROVIDER_H_
+#define CHROME_BROWSER_CHROMEOS_POLICY_AFFILIATED_INVALIDATION_SERVICE_PROVIDER_H_
+
+#include "base/macros.h"
+#include "base/memory/scoped_ptr.h"
+#include "base/memory/scoped_vector.h"
+#include "base/observer_list.h"
+#include "content/public/browser/notification_observer.h"
+#include "content/public/browser/notification_registrar.h"
+
+namespace invalidation {
+class InvalidationService;
+class TiclInvalidationService;
+}
+
+namespace policy {
+
+// This class provides access to an |InvalidationService| that can be used to
+// subscribe to invalidations generated by the device's enrollment domain, e.g.
+// policy pushing and remote commands for:
+// * the device itself
+// * device-local accounts
+// * other users affiliated with the enrollment domain
+//
+// If an affiliated user with a connected invalidation service is logged in,
+// that invalidation service will be used to conserve server resources. If there
+// are no logged-in users matching these criteria, a device-global
+// |TiclInvalidationService| is spun up.
+// The class monitors the status of the invalidation services and switches
+// between them whenever the service currently in use disconnects or the
+// device-global invalidation service can be replaced with another service that
+// just connected.
+class AffiliatedInvalidationServiceProvider
+    : public content::NotificationObserver {
+ public:
+  class Consumer {
+   public:
+    // This method is called when the invalidation service that the consumer
+    // should use changes:
+    // * If |invalidation_service| is a nullptr, no invalidation service is
+    //   currently available for use.
+    // * Otherwise, |invalidation_service| is the invalidation service that the
+    //   consumer should use. It is guaranteed to be connected. Any previously
+    //   provided invalidation services must no longer be used.
+    virtual void OnInvalidationServiceSet(
+        invalidation::InvalidationService* invalidation_service) = 0;
+
+   protected:
+    virtual ~Consumer();
+  };
+
+  AffiliatedInvalidationServiceProvider();
+  ~AffiliatedInvalidationServiceProvider() override;
+
+  // content::NotificationObserver:
+  void Observe(int type,
+               const content::NotificationSource& source,
+               const content::NotificationDetails& details) override;
+
+  // Indicates that |consumer| is interested in using the shared
+  // |InvalidationService|. The consumer's OnInvalidationServiceSet() method
+  // will be called back when a connected invalidation service becomes
+  // available. If an invalidation service is available already, the callback
+  // will occur synchronously. The |consumer| must be unregistered before |this|
+  // is destroyed.
+  void RegisterConsumer(Consumer* consumer);
+
+  // Indicates that |consumer| is no longer interested in using the
+  // shared |InvalidationService|.
+  void UnregisterConsumer(Consumer* consumer);
+
+  // Shuts down the provider. Once the provider is shut down, it no longer makes
+  // any invalidation service available to consumers, no longer observes any
+  // per-profile invalidation services and no longer maintains a device-global
+  // invalidation service.
+  void Shutdown();
+
+  invalidation::TiclInvalidationService*
+      GetDeviceInvalidationServiceForTest() const;
+
+ private:
+  // Helper that monitors the status of a single |InvalidationService|.
+  class InvalidationServiceObserver;
+
+  // Status updates received from |InvalidationServiceObserver|s.
+  void OnInvalidationServiceConnected(
+      invalidation::InvalidationService* invalidation_service);
+  void OnInvalidationServiceDisconnected(
+      invalidation::InvalidationService* invalidation_service);
+
+  // Checks whether a connected |InvalidationService| affiliated with the
+  // device's enrollment domain is available. If so, notifies the consumers.
+  // Otherwise, consumers will be notified once such an invalidation service
+  // becomes available.
+  // Further ensures that a device-global invalidation service is running iff
+  // there is no other connected service available for use and there is at least
+  // one registered consumer.
+  void FindConnectedInvalidationService();
+
+  // Choose |invalidation_service| as the shared invalidation service and notify
+  // consumers.
+  void SetInvalidationService(
+      invalidation::InvalidationService* invalidation_service);
+
+  // Destroy the device-global invalidation service, if any.
+  void DestroyDeviceInvalidationService();
+
+  content::NotificationRegistrar registrar_;
+
+  // Device-global invalidation service.
+  scoped_ptr<invalidation::TiclInvalidationService>
+      device_invalidation_service_;
+
+  // State observer for the device-global invalidation service.
+  scoped_ptr<InvalidationServiceObserver> device_invalidation_service_observer_;
+
+  // State observers for logged-in users' invalidation services.
+  ScopedVector<InvalidationServiceObserver>
+      profile_invalidation_service_observers_;
+
+  // The invalidation service currently used by consumers. nullptr if there are
+  // no registered consumers or no connected invalidation service is available
+  // for use.
+  invalidation::InvalidationService* invalidation_service_;
+
+  ObserverList<Consumer, true> consumers_;
+  int consumer_count_;
+
+  bool is_shut_down_;
+
+  DISALLOW_COPY_AND_ASSIGN(AffiliatedInvalidationServiceProvider);
+};
+
+}  // namespace policy
+
+#endif  // CHROME_BROWSER_CHROMEOS_POLICY_AFFILIATED_INVALIDATION_SERVICE_PROVIDER_H_