1// Copyright (c) 2012 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 CHROME_BROWSER_POLICY_CONFIGURATION_POLICY_PROVIDER_H_
6#define CHROME_BROWSER_POLICY_CONFIGURATION_POLICY_PROVIDER_H_
7
8#include "base/basictypes.h"
9#include "base/memory/ref_counted.h"
10#include "base/memory/scoped_ptr.h"
11#include "base/observer_list.h"
12#include "chrome/browser/policy/policy_bundle.h"
13#include "chrome/browser/policy/policy_service.h"
14
15namespace policy {
16
17class PolicyDomainDescriptor;
18
19// A mostly-abstract super class for platform-specific policy providers.
20// Platform-specific policy providers (Windows Group Policy, gconf,
21// etc.) should implement a subclass of this class.
22class ConfigurationPolicyProvider {
23 public:
24  class Observer {
25   public:
26    virtual ~Observer();
27    virtual void OnUpdatePolicy(ConfigurationPolicyProvider* provider) = 0;
28  };
29
30  ConfigurationPolicyProvider();
31
32  // Policy providers can be deleted quite late during shutdown of the browser,
33  // and it's not guaranteed that the message loops will still be running when
34  // this is invoked. Override Shutdown() instead for cleanup code that needs
35  // to post to the FILE thread, for example.
36  virtual ~ConfigurationPolicyProvider();
37
38  // Invoked as soon as the main message loops are spinning. Policy providers
39  // are created early during startup to provide the initial policies; the
40  // Init() call allows them to perform initialization tasks that require
41  // running message loops.
42  virtual void Init();
43
44  // Must be invoked before deleting the provider. Implementations can override
45  // this method to do appropriate cleanup while threads are still running, and
46  // must also invoke ConfigurationPolicyProvider::Shutdown().
47  // The provider should keep providing the current policies after Shutdown()
48  // is invoked, it only has to stop updating.
49  virtual void Shutdown();
50
51  // Returns the current PolicyBundle.
52  const PolicyBundle& policies() const { return policy_bundle_; }
53
54  // Check whether this provider has completed initialization for the given
55  // policy |domain|. This is used to detect whether initialization is done in
56  // case implementations need to do asynchronous operations for initialization.
57  virtual bool IsInitializationComplete(PolicyDomain domain) const;
58
59  // Asks the provider to refresh its policies. All the updates caused by this
60  // call will be visible on the next call of OnUpdatePolicy on the observers,
61  // which are guaranteed to happen even if the refresh fails.
62  // It is possible that Shutdown() is called first though, and
63  // OnUpdatePolicy won't be called if that happens.
64  virtual void RefreshPolicies() = 0;
65
66  // Observers must detach themselves before the provider is deleted.
67  virtual void AddObserver(Observer* observer);
68  virtual void RemoveObserver(Observer* observer);
69
70  // Notifies the provider that there is interest in loading policy for the
71  // listed components in the given |descriptor|. The list is complete; all the
72  // components that matter for the domain are included, and components not
73  // included can be discarded. The provider can ignore this information or use
74  // it to selectively load the corresponding policy from its sources.
75  virtual void RegisterPolicyDomain(
76      scoped_refptr<const PolicyDomainDescriptor> descriptor);
77
78 protected:
79  // Subclasses must invoke this to update the policies currently served by
80  // this provider. UpdatePolicy() takes ownership of |policies|.
81  // The observers are notified after the policies are updated.
82  void UpdatePolicy(scoped_ptr<PolicyBundle> bundle);
83
84 private:
85  // The policies currently configured at this provider.
86  PolicyBundle policy_bundle_;
87
88  // Whether Shutdown() has been invoked.
89  bool did_shutdown_;
90
91  ObserverList<Observer, true> observer_list_;
92
93  DISALLOW_COPY_AND_ASSIGN(ConfigurationPolicyProvider);
94};
95
96}  // namespace policy
97
98#endif  // CHROME_BROWSER_POLICY_CONFIGURATION_POLICY_PROVIDER_H_
99