device/hid/hid_service.h

   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 DEVICE_HID_HID_SERVICE_H_
   6 #define DEVICE_HID_HID_SERVICE_H_
   7
   8 #include <map>
   9 #include <string>
  10 #include <vector>
  11
  12 #include "base/bind_helpers.h"
  13 #include "base/memory/ref_counted.h"
  14 #include "base/observer_list.h"
  15 #include "base/single_thread_task_runner.h"
  16 #include "base/threading/thread_checker.h"
  17 #include "device/hid/hid_device_info.h"
  18
  19 namespace device {
  20
  21 class HidConnection;
  22
  23 // The HidService keeps track of human interface devices connected to the
  24 // system. Call HidService::GetInstance to get the singleton instance.
  25 class HidService {
  26  public:
  27   class Observer {
  28    public:
  29     virtual void OnDeviceAdded(const HidDeviceInfo& info) {}
  30     virtual void OnDeviceRemoved(const HidDeviceInfo& info) {}
  31   };
  32
  33   typedef base::Callback<void(const std::vector<HidDeviceInfo>&)>
  34       GetDevicesCallback;
  35   typedef base::Callback<void(scoped_refptr<HidConnection> connection)>
  36       ConnectCallback;
  37
  38   // Gets a pointer to the HidService singleton. This function should be called
  39   // on a thread with a MessageLoopForUI and be passed the task runner for a
  40   // thread with a MessageLoopForIO.
  41   static HidService* GetInstance(
  42       scoped_refptr<base::SingleThreadTaskRunner> file_task_runner);
  43
  44   static void SetInstanceForTest(HidService* instance);
  45
  46   // Enumerates available devices. The provided callback will always be posted
  47   // to the calling thread's task runner.
  48   virtual void GetDevices(const GetDevicesCallback& callback);
  49
  50   void AddObserver(Observer* observer);
  51   void RemoveObserver(Observer* observer);
  52
  53   // Fills in a DeviceInfo struct with info for the given device_id.
  54   // Returns |true| if successful or |false| if |device_id| is invalid.
  55   bool GetDeviceInfo(const HidDeviceId& device_id, HidDeviceInfo* info) const;
  56
  57   // Opens a connection to a device. The callback will be run with null on
  58   // failure.
  59   virtual void Connect(const HidDeviceId& device_id,
  60                        const ConnectCallback& callback) = 0;
  61
  62  protected:
  63   friend void base::DeletePointer<HidService>(HidService* service);
  64   friend class HidConnectionTest;
  65
  66   typedef std::map<HidDeviceId, HidDeviceInfo> DeviceMap;
  67
  68   HidService();
  69   virtual ~HidService();
  70
  71   void AddDevice(const HidDeviceInfo& info);
  72   void RemoveDevice(const HidDeviceId& device_id);
  73   void FirstEnumerationComplete();
  74
  75   const DeviceMap& devices() const { return devices_; }
  76
  77   base::ThreadChecker thread_checker_;
  78
  79  private:
  80   DeviceMap devices_;
  81   bool enumeration_ready_;
  82   std::vector<GetDevicesCallback> pending_enumerations_;
  83   ObserverList<Observer> observer_list_;
  84
  85   DISALLOW_COPY_AND_ASSIGN(HidService);
  86 };
  87
  88 }  // namespace device
  89
  90 #endif  // DEVICE_HID_HID_SERVICE_H_