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.
5 #ifndef CHROME_BROWSER_POLICY_POLICY_SERVICE_H_
6 #define CHROME_BROWSER_POLICY_POLICY_SERVICE_H_
11 #include "base/basictypes.h"
12 #include "base/callback.h"
13 #include "base/memory/ref_counted.h"
14 #include "chrome/browser/policy/policy_map.h"
15 #include "components/policy/core/common/policy_namespace.h"
19 class PolicyDomainDescriptor;
21 // The PolicyService merges policies from all available sources, taking into
22 // account their priorities. Policy clients can retrieve policy for their domain
23 // and register for notifications on policy updates.
25 // The PolicyService is available from BrowserProcess as a global singleton.
26 // There is also a PolicyService for browser-wide policies available from
27 // BrowserProcess as a global singleton.
32 // Invoked whenever policies for the given |ns| namespace are modified.
33 // This is only invoked for changes that happen after AddObserver is called.
34 // |previous| contains the values of the policies before the update,
35 // and |current| contains the current values.
36 virtual void OnPolicyUpdated(const PolicyNamespace& ns,
37 const PolicyMap& previous,
38 const PolicyMap& current) = 0;
40 // Invoked at most once for each |domain|, when the PolicyService becomes
41 // ready. If IsInitializationComplete() is false, then this will be invoked
42 // once all the policy providers have finished loading their policies for
44 virtual void OnPolicyServiceInitialized(PolicyDomain domain) {}
47 virtual ~Observer() {}
50 virtual ~PolicyService() {}
52 // Observes changes to all components of the given |domain|.
53 virtual void AddObserver(PolicyDomain domain, Observer* observer) = 0;
55 virtual void RemoveObserver(PolicyDomain domain, Observer* observer) = 0;
57 // Registers the |descriptor| of a policy domain, indicated by
58 // |descriptor->domain()|. This overrides the descriptor previously set, if
60 // This registration signals that there is interest in receiving policy for
61 // the components listed in the descriptor. The policy providers will try to
62 // load policy for these components, and validate it against the descriptor.
63 // Cached data for components that aren't registered anymore may be dropped.
64 virtual void RegisterPolicyDomain(
65 scoped_refptr<const PolicyDomainDescriptor> descriptor) = 0;
67 virtual const PolicyMap& GetPolicies(const PolicyNamespace& ns) const = 0;
69 virtual scoped_refptr<const PolicyDomainDescriptor> GetPolicyDomainDescriptor(
70 PolicyDomain domain) const = 0;
72 // The PolicyService loads policy from several sources, and some require
73 // asynchronous loads. IsInitializationComplete() returns true once all
74 // sources have loaded their policies for the given |domain|.
75 // It is safe to read policy from the PolicyService even if
76 // IsInitializationComplete() is false; there will be an OnPolicyUpdated()
77 // notification once new policies become available.
79 // OnPolicyServiceInitialized() is called when IsInitializationComplete()
80 // becomes true, which happens at most once for each domain.
81 // If IsInitializationComplete() is already true for |domain| when an Observer
82 // is registered, then that Observer will not receive an
83 // OnPolicyServiceInitialized() notification.
84 virtual bool IsInitializationComplete(PolicyDomain domain) const = 0;
86 // Asks the PolicyService to reload policy from all available policy sources.
87 // |callback| is invoked once every source has reloaded its policies, and
88 // GetPolicies() is guaranteed to return the updated values at that point.
89 virtual void RefreshPolicies(const base::Closure& callback) = 0;
92 // A registrar that only observes changes to particular policies within the
93 // PolicyMap for the given policy namespace.
94 class PolicyChangeRegistrar : public PolicyService::Observer {
96 typedef base::Callback<void(const Value*, const Value*)> UpdateCallback;
98 // Observes updates to the given (domain, component_id) namespace in the given
99 // |policy_service|, and notifies |observer| whenever any of the registered
100 // policy keys changes. Both the |policy_service| and the |observer| must
102 PolicyChangeRegistrar(PolicyService* policy_service,
103 const PolicyNamespace& ns);
105 virtual ~PolicyChangeRegistrar();
107 // Will invoke |callback| whenever |policy_name| changes its value, as long
108 // as this registrar exists.
109 // Only one callback can be registed per policy name; a second call with the
110 // same |policy_name| will overwrite the previous callback.
111 void Observe(const std::string& policy_name, const UpdateCallback& callback);
113 // Implementation of PolicyService::Observer:
114 virtual void OnPolicyUpdated(const PolicyNamespace& ns,
115 const PolicyMap& previous,
116 const PolicyMap& current) OVERRIDE;
119 typedef std::map<std::string, UpdateCallback> CallbackMap;
121 PolicyService* policy_service_;
123 CallbackMap callback_map_;
125 DISALLOW_COPY_AND_ASSIGN(PolicyChangeRegistrar);
128 } // namespace policy
130 #endif // CHROME_BROWSER_POLICY_POLICY_SERVICE_H_