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// Copyright 2014 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#ifndef DEVICE_HID_HID_SERVICE_H_
#define DEVICE_HID_HID_SERVICE_H_
#include <map>
#include <memory>
#include <string>
#include <vector>
#include "base/bind_helpers.h"
#include "base/logging.h"
#include "base/macros.h"
#include "base/memory/ref_counted.h"
#include "base/observer_list.h"
#include "base/single_thread_task_runner.h"
#include "base/task_scheduler/task_traits.h"
#include "base/threading/thread_checker.h"
#include "device/hid/hid_device_info.h"
namespace device {
class HidConnection;
// The HidService keeps track of human interface devices connected to the
// system. Call HidService::GetInstance to get the singleton instance.
class HidService {
public:
class Observer {
public:
virtual void OnDeviceAdded(scoped_refptr<HidDeviceInfo> info);
// Notifies all observers that a device is being removed, called before
// removing the device from HidService. Observers should not depend on the
// order in which they are notified of the OnDeviceRemove event.
virtual void OnDeviceRemoved(scoped_refptr<HidDeviceInfo> info);
// Notifies all observers again, after having first notified all observers
// with OnDeviceRemoved and removed the device from internal structures.
// Each observer must not depend on any other observers' awareness of the
// device as they could be cleaned up in any order.
virtual void OnDeviceRemovedCleanup(scoped_refptr<HidDeviceInfo> info);
};
using GetDevicesCallback =
base::Callback<void(const std::vector<scoped_refptr<HidDeviceInfo>>&)>;
using ConnectCallback =
base::Callback<void(scoped_refptr<HidConnection> connection)>;
static constexpr base::TaskTraits kBlockingTaskTraits = {
base::MayBlock(), base::TaskPriority::USER_VISIBLE,
base::TaskShutdownBehavior::CONTINUE_ON_SHUTDOWN};
// This function should be called on a thread with a MessageLoopForUI.
static std::unique_ptr<HidService> Create();
virtual ~HidService();
// Enumerates available devices. The provided callback will always be posted
// to the calling thread's task runner.
virtual void GetDevices(const GetDevicesCallback& callback);
void AddObserver(Observer* observer);
void RemoveObserver(Observer* observer);
// Fills in a DeviceInfo struct with info for the given device_id.
// Returns |nullptr| if |device_id| is invalid.
scoped_refptr<HidDeviceInfo> GetDeviceInfo(
const HidDeviceId& device_id) const;
// Opens a connection to a device. The callback will be run with null on
// failure.
virtual void Connect(const HidDeviceId& device_id,
const ConnectCallback& callback) = 0;
protected:
friend class HidConnectionTest;
typedef std::map<HidDeviceId, scoped_refptr<HidDeviceInfo>> DeviceMap;
HidService();
void AddDevice(scoped_refptr<HidDeviceInfo> info);
void RemoveDevice(const HidDeviceId& device_id);
void FirstEnumerationComplete();
const DeviceMap& devices() const { return devices_; }
base::ThreadChecker thread_checker_;
private:
DeviceMap devices_;
bool enumeration_ready_ = false;
std::vector<GetDevicesCallback> pending_enumerations_;
base::ObserverList<Observer, true> observer_list_;
DISALLOW_COPY_AND_ASSIGN(HidService);
};
} // namespace device
#endif // DEVICE_HID_HID_SERVICE_H_