1 // Copyright 2014 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_CHROMEOS_POLICY_SERVER_BACKED_STATE_KEYS_BROKER_H_ 6 #define CHROME_BROWSER_CHROMEOS_POLICY_SERVER_BACKED_STATE_KEYS_BROKER_H_ 7 8 #include <string> 9 #include <vector> 10 11 #include "base/callback.h" 12 #include "base/callback_list.h" 13 #include "base/macros.h" 14 #include "base/memory/ref_counted.h" 15 #include "base/memory/weak_ptr.h" 16 17 namespace base { 18 class TaskRunner; 19 } 20 21 namespace chromeos { 22 class SessionManagerClient; 23 } 24 25 namespace policy { 26 27 // Brokers server-backed state keys for the device. Retrieves them from session 28 // manager via DBus and refreshes them periodically. Consumers can register 29 // callbacks to invoke when the state keys change. 30 class ServerBackedStateKeysBroker { 31 public: 32 typedef scoped_ptr<base::CallbackList<void()>::Subscription> Subscription; 33 typedef base::Callback<void(const std::vector<std::string>&)> 34 StateKeysCallback; 35 36 ServerBackedStateKeysBroker( 37 chromeos::SessionManagerClient* session_manager_client, 38 scoped_refptr<base::TaskRunner> delayed_task_runner); 39 ~ServerBackedStateKeysBroker(); 40 41 // Registers a callback to be invoked whenever the state keys get updated. 42 // Note that consuming code needs to hold on to the returned Subscription as 43 // long as it wants to receive the callback. If the state keys haven't been 44 // requested yet, calling this will also trigger their initial fetch. 45 Subscription RegisterUpdateCallback(const base::Closure& callback); 46 47 // Requests state keys asynchronously. Invokes the passed callback exactly 48 // once (unless |this| gets destroyed before the callback happens), with the 49 // current state keys passed as a parameter to the callback. If there's a 50 // problem determining the state keys, the passed vector will be empty. 51 void RequestStateKeys(const StateKeysCallback& callback); 52 53 // Get the set of current state keys. Empty if state keys are unavailable 54 // or pending retrieval. 55 const std::vector<std::string>& state_keys() const { return state_keys_; } 56 57 // Returns the state key for the current point in time. Returns an empty 58 // string if state keys are unavailable or pending retrieval. 59 std::string current_state_key() const { 60 return state_keys_.empty() ? std::string() : state_keys_.front(); 61 } 62 63 // Whether state key retrieval is pending. 64 bool pending() const { return !initial_retrieval_completed_; } 65 66 // Whether state keys are available. 67 bool available() const { return !state_keys_.empty(); } 68 69 private: 70 // Asks |session_manager_client_| to provide current state keys.. 71 void FetchStateKeys(); 72 73 // Stores newly-received state keys and notifies consumers. 74 void StoreStateKeys(const std::vector<std::string>& state_keys); 75 76 chromeos::SessionManagerClient* session_manager_client_; 77 78 scoped_refptr<base::TaskRunner> delayed_task_runner_; 79 80 // The current set of state keys. 81 std::vector<std::string> state_keys_; 82 83 // Whether a request for state keys is pending. 84 bool requested_; 85 86 // Whether the initial retrieval operation completed. 87 bool initial_retrieval_completed_; 88 89 // List of callbacks to receive update notifications. 90 base::CallbackList<void()> update_callbacks_; 91 92 // List of pending one-shot state key request callbacks. 93 std::vector<StateKeysCallback> request_callbacks_; 94 95 base::WeakPtrFactory<ServerBackedStateKeysBroker> weak_factory_; 96 97 DISALLOW_COPY_AND_ASSIGN(ServerBackedStateKeysBroker); 98 }; 99 100 } // namespace policy 101 102 #endif // CHROME_BROWSER_CHROMEOS_POLICY_SERVER_BACKED_STATE_KEYS_BROKER_H_ 103
