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 BASE_POWER_MONITOR_POWER_MONITOR_SOURCE_H_ 6 #define BASE_POWER_MONITOR_POWER_MONITOR_SOURCE_H_ 7 8 #include "base/base_export.h" 9 #include "base/macros.h" 10 #include "base/memory/ref_counted.h" 11 #include "base/observer_list_threadsafe.h" 12 #include "base/synchronization/lock.h" 13 14 namespace base { 15 16 class PowerMonitor; 17 18 // Communicates power state changes to the power monitor. 19 class BASE_EXPORT PowerMonitorSource { 20 public: 21 PowerMonitorSource(); 22 virtual ~PowerMonitorSource(); 23 24 // Normalized list of power events. 25 enum PowerEvent { 26 POWER_STATE_EVENT, // The Power status of the system has changed. 27 SUSPEND_EVENT, // The system is being suspended. 28 RESUME_EVENT // The system is being resumed. 29 }; 30 31 // Is the computer currently on battery power. Can be called on any thread. 32 bool IsOnBatteryPower(); 33 34 protected: 35 friend class PowerMonitorTest; 36 37 // Friend function that is allowed to access the protected ProcessPowerEvent. 38 friend void ProcessPowerEventHelper(PowerEvent); 39 40 // Get the process-wide PowerMonitorSource (if not present, returns NULL). 41 static PowerMonitorSource* Get(); 42 43 // ProcessPowerEvent should only be called from a single thread, most likely 44 // the UI thread or, in child processes, the IO thread. 45 static void ProcessPowerEvent(PowerEvent event_id); 46 47 // Platform-specific method to check whether the system is currently 48 // running on battery power. Returns true if running on batteries, 49 // false otherwise. 50 virtual bool IsOnBatteryPowerImpl() = 0; 51 52 private: 53 bool on_battery_power_; 54 bool suspended_; 55 56 // This lock guards access to on_battery_power_, to ensure that 57 // IsOnBatteryPower can be called from any thread. 58 Lock battery_lock_; 59 60 DISALLOW_COPY_AND_ASSIGN(PowerMonitorSource); 61 }; 62 63 } // namespace base 64 65 #endif // BASE_POWER_MONITOR_POWER_MONITOR_SOURCE_H_ 66