components/policy/core/common/async_policy_provider.h

   1 // Copyright 2013 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #ifndef COMPONENTS_POLICY_CORE_COMMON_ASYNC_POLICY_PROVIDER_H_
   6 #define COMPONENTS_POLICY_CORE_COMMON_ASYNC_POLICY_PROVIDER_H_
   7
   8 #include "base/cancelable_callback.h"
   9 #include "base/memory/ref_counted.h"
  10 #include "base/memory/scoped_ptr.h"
  11 #include "base/memory/weak_ptr.h"
  12 #include "base/threading/non_thread_safe.h"
  13 #include "components/policy/core/common/configuration_policy_provider.h"
  14 #include "components/policy/policy_export.h"
  15
  16 namespace base {
  17 class SingleThreadTaskRunner;
  18 }
  19
  20 namespace policy {
  21
  22 class AsyncPolicyLoader;
  23 class PolicyBundle;
  24 class SchemaRegistry;
  25
  26 // A policy provider that loads its policies asynchronously on a background
  27 // thread. Platform-specific providers are created by passing an implementation
  28 // of AsyncPolicyLoader to a new AsyncPolicyProvider.
  29 class POLICY_EXPORT AsyncPolicyProvider : public ConfigurationPolicyProvider,
  30                                           public base::NonThreadSafe {
  31  public:
  32   // The AsyncPolicyProvider does a synchronous load in its constructor, and
  33   // therefore it needs the |registry| at construction time. The same |registry|
  34   // should be passed later to Init().
  35   AsyncPolicyProvider(SchemaRegistry* registry,
  36                       scoped_ptr<AsyncPolicyLoader> loader);
  37   ~AsyncPolicyProvider() override;
  38
  39   // ConfigurationPolicyProvider implementation.
  40   void Init(SchemaRegistry* registry) override;
  41   void Shutdown() override;
  42   void RefreshPolicies() override;
  43
  44  private:
  45   // Helper for RefreshPolicies().
  46   void ReloadAfterRefreshSync();
  47
  48   // Invoked with the latest bundle loaded by the |loader_|.
  49   void OnLoaderReloaded(scoped_ptr<PolicyBundle> bundle);
  50
  51   // Callback passed to the loader that it uses to pass back the current policy
  52   // bundle to the provider. This is invoked on the background thread and
  53   // forwards to OnLoaderReloaded() on the runner that owns the provider,
  54   // if |weak_this| is still valid.
  55   static void LoaderUpdateCallback(
  56                   scoped_refptr<base::SingleThreadTaskRunner> runner,
  57                   base::WeakPtr<AsyncPolicyProvider> weak_this,
  58                   scoped_ptr<PolicyBundle> bundle);
  59
  60   // The |loader_| that does the platform-specific policy loading. It lives
  61   // on the background thread but is owned by |this|.
  62   scoped_ptr<AsyncPolicyLoader> loader_;
  63
  64   // Callback used to synchronize RefreshPolicies() calls with the background
  65   // thread. See the implementation for the details.
  66   base::CancelableClosure refresh_callback_;
  67
  68   // Used to get a WeakPtr to |this| for the update callback given to the
  69   // loader.
  70   base::WeakPtrFactory<AsyncPolicyProvider> weak_factory_;
  71
  72   DISALLOW_COPY_AND_ASSIGN(AsyncPolicyProvider);
  73 };
  74
  75 }  // namespace policy
  76
  77 #endif  // COMPONENTS_POLICY_CORE_COMMON_ASYNC_POLICY_PROVIDER_H_