device/hid/device_monitor_linux.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_DEVICE_MONITOR_LINUX_H_
   6 #define DEVICE_HID_DEVICE_MONITOR_LINUX_H_
   7
   8 #include <string>
   9
  10 #include "base/compiler_specific.h"
  11 #include "base/macros.h"
  12 #include "base/memory/scoped_ptr.h"
  13 #include "base/message_loop/message_loop.h"
  14 #include "base/message_loop/message_pump_libevent.h"
  15 #include "base/observer_list.h"
  16 #include "base/threading/thread_checker.h"
  17 #include "device/udev_linux/scoped_udev.h"
  18
  19 struct udev_device;
  20
  21 namespace device {
  22
  23 // This class listends for notifications from libudev about
  24 // connected/disconnected devices. This class is *NOT* thread-safe and
  25 // all methods must be accessed from the FILE thread.
  26 class DeviceMonitorLinux : public base::MessageLoop::DestructionObserver,
  27                            public base::MessagePumpLibevent::Watcher {
  28  public:
  29   typedef base::Callback<void(udev_device* device)> EnumerateCallback;
  30
  31   class Observer {
  32    public:
  33     virtual ~Observer() {}
  34     virtual void OnDeviceAdded(udev_device* device) = 0;
  35     virtual void OnDeviceRemoved(udev_device* device) = 0;
  36   };
  37
  38   DeviceMonitorLinux();
  39
  40   static DeviceMonitorLinux* GetInstance();
  41   static bool HasInstance();
  42
  43   void AddObserver(Observer* observer);
  44   void RemoveObserver(Observer* observer);
  45
  46   ScopedUdevDevicePtr GetDeviceFromPath(const std::string& path);
  47   void Enumerate(const EnumerateCallback& callback);
  48
  49   // Implements base::MessageLoop::DestructionObserver
  50   void WillDestroyCurrentMessageLoop() override;
  51
  52   // Implements base::MessagePumpLibevent::Watcher
  53   void OnFileCanReadWithoutBlocking(int fd) override;
  54   void OnFileCanWriteWithoutBlocking(int fd) override;
  55
  56  private:
  57   friend struct base::DefaultDeleter<DeviceMonitorLinux>;
  58
  59   ~DeviceMonitorLinux() override;
  60
  61   ScopedUdevPtr udev_;
  62   ScopedUdevMonitorPtr monitor_;
  63   int monitor_fd_;
  64   base::MessagePumpLibevent::FileDescriptorWatcher monitor_watcher_;
  65
  66   ObserverList<Observer> observers_;
  67
  68   base::ThreadChecker thread_checker_;
  69
  70   DISALLOW_COPY_AND_ASSIGN(DeviceMonitorLinux);
  71 };
  72
  73 }  // namespace device
  74
  75 #endif  // DEVICE_HID_DEVICE_MONITOR_LINUX_H_