Add AffiliatedInvalidationServiceProvider

chrome/browser/chromeos/policy/affiliated_invalidation_service_provider.h

+// Copyright 2014 The Chromium Authors. All rights reserved.

[Mattias Nissler (ping if slow), 2015/01/13 09:50:15]

2015 :)

[bartfab (slow), 2015/01/13 17:45:23]

This is what happens when you write code just before Christmas but do not manage
to send it out for review until the next year... :).

+// 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:
+    // When this method is called, the consumer may start using the provided
+    // |invalidation_service|. The invalidation service is guaranteed to be
+    // connected.
+    virtual void OnInvalidationServiceSet(
+        invalidation::InvalidationService* invalidation_service) = 0;
+
+    // When this method is called, the consumer must stop using the previously
+    // provided invalidation service.
+    virtual void OnInvalidationServiceReset() = 0;

[Mattias Nissler (ping if slow), 2015/01/13 09:50:15]

Could as well just call OnInvalidationSeviceSet(nullptr)? Would that make things
simpler or not?

[bartfab (slow), 2015/01/13 17:45:23]

It shortens the unit test file a bit. Done.

+
+   protected:
+    virtual ~Consumer();
+  };
+
+  AffiliatedInvalidationServiceProvider();
+  virtual ~AffiliatedInvalidationServiceProvider();
+
+  // content::NotificationObserver:
+  virtual 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);
+
+  invalidation::TiclInvalidationService*
+      GetDeviceInvalidationServiceForTest() const;
+  bool HasDeviceInvalidationServiceObserverForTest() const;
+  int GetProfileInvalidationServiceObserverCountForTest() const;
+  invalidation::InvalidationService* GetInvalidationServiceForTest() 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);
+
+  // Clear the shared invalidation service and notify consumers.
+  void ResetInvalidationService();
+
+  // 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_;
+
+  DISALLOW_COPY_AND_ASSIGN(AffiliatedInvalidationServiceProvider);
+};
+
+}  // namespace policy
+
+#endif  // CHROME_BROWSER_CHROMEOS_POLICY_AFFILIATED_INVALIDATION_SERVICE_PROVIDER_H_