Add the AsyncPolicyProvider and AsyncPolicyLoader

chrome/browser/policy/async_policy_provider.h

+// Copyright (c) 2012 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_POLICY_ASYNC_POLICY_PROVIDER_H_
+#define CHROME_BROWSER_POLICY_ASYNC_POLICY_PROVIDER_H_
+#pragma once
+
+#include "base/cancelable_callback.h"
+#include "base/memory/ref_counted.h"
+#include "base/memory/scoped_ptr.h"
+#include "base/memory/weak_ptr.h"
+#include "base/threading/non_thread_safe.h"
+#include "chrome/browser/policy/configuration_policy_provider.h"
+
+namespace base {
+class MessageLoopProxy;
+}
+
+namespace policy {
+
+class AsyncPolicyLoader;
+class PolicyBundle;
+
+// A policy provider that loads its policies asynchronously on the FILE thread.
+// Platform-specific providers are created by passing an implementation of
+// AsyncPolicyLoader to a new AsyncPolicyProvider.
+class AsyncPolicyProvider : public ConfigurationPolicyProvider,
+                            public base::NonThreadSafe {
+ public:
+  AsyncPolicyProvider(const PolicyDefinitionList* policy_list,
+                      scoped_ptr<AsyncPolicyLoader> loader);
+  virtual ~AsyncPolicyProvider();
+
+  // ConfigurationPolicyProvider implementation.
+  virtual void RefreshPolicies() OVERRIDE;
+
+ private:
+  // Resumes initialization once the loops are spinning.
+  void InitWithLoopsReady();
+
+  // Helper for RefreshPolicies().
+  void ReloadAfterRefreshSync();
+
+  // Invoked with the latest bundle loaded by the |loader_|.
+  void OnLoaderReloaded(scoped_ptr<PolicyBundle> bundle);
+
+  // Callback passed to the loader that it uses to pass back the current policy
+  // bundle to the provider. This is invoked on the FILE thread and forwards
+  // to OnLoaderReloaded() on the loop that owns the provider, if |weak_this| is
+  // still valid.
+  static void LoaderUpdateCallback(scoped_refptr<base::MessageLoopProxy> loop,
+                                   base::WeakPtr<AsyncPolicyProvider> weak_this,
+                                   scoped_ptr<PolicyBundle> bundle);
+
+  // The |loader_| that does the platform-specific policy loading. It lives
+  // on the FILE thread, and always outlives |this|.
+  AsyncPolicyLoader* loader_;
+
+  // Used to get a WeakPtr to |this| for the update callback given to the
+  // loader.
+  base::WeakPtrFactory<AsyncPolicyProvider> weak_factory_;
+
+  // Callback used to synchronize RefreshPolicies() calls with the FILE thread.
+  // See the implementation for the details.
+  base::CancelableClosure refresh_callback_;
+
+  DISALLOW_COPY_AND_ASSIGN(AsyncPolicyProvider);
+};
+
+}  // namespace policy
+
+#endif  // CHROME_BROWSER_POLICY_ASYNC_POLICY_PROVIDER_H_