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 CONTENT_RENDERER_DEVICE_SENSOR_EVENT_PUMP_H_ 6 #define CONTENT_RENDERER_DEVICE_SENSOR_EVENT_PUMP_H_ 7 8 #include "base/memory/shared_memory.h" 9 #include "base/timer/timer.h" 10 #include "content/public/renderer/render_process_observer.h" 11 12 namespace content { 13 class RenderThread; 14 15 class CONTENT_EXPORT DeviceSensorEventPump : public RenderProcessObserver { 16 public: 17 // Default delay between subsequent firing of events. 18 static const int kDefaultPumpDelayMillis; 19 20 int GetDelayMillis() const; 21 22 void Attach(RenderThread* thread); 23 virtual bool OnControlMessageReceived(const IPC::Message& message) = 0; 24 25 protected: 26 // Constructor for a pump with default delay. 27 DeviceSensorEventPump(); 28 29 // Constructor for a pump with a given delay. 30 explicit DeviceSensorEventPump(int pump_delay_millis); 31 virtual ~DeviceSensorEventPump(); 32 33 // The pump is a tri-state automaton with allowed transitions as follows: 34 // STOPPED -> PENDING_START 35 // PENDING_START -> RUNNING 36 // PENDING_START -> STOPPED 37 // RUNNING -> STOPPED 38 enum PumpState { 39 STOPPED, 40 RUNNING, 41 PENDING_START 42 }; 43 44 bool RequestStart(); 45 void OnDidStart(base::SharedMemoryHandle handle); 46 bool Stop(); 47 48 virtual void FireEvent() = 0; 49 virtual bool InitializeReader(base::SharedMemoryHandle handle) = 0; 50 virtual bool SendStartMessage() = 0; 51 virtual bool SendStopMessage() = 0; 52 53 int pump_delay_millis_; 54 PumpState state_; 55 base::RepeatingTimer<DeviceSensorEventPump> timer_; 56 }; 57 58 } // namespace content 59 60 #endif // CONTENT_RENDERER_DEVICE_SENSOR_EVENT_PUMP_H_ 61
