使用Swift 3收听IOKit事件

Question

这是我在Swift/Xcode中的第一个程序。完整的源代码和xcode项目可以在GitHub中获得。

我想复习的部分是IOKeyEventMonitor.swift。

//Copyright [2016] Jean Helou
//
//Licensed under the Apache License, Version 2.0 (the "License");
//you may not use this file except in compliance with the License.
//You may obtain a copy of the License at
//
//http://www.apache.org/licenses/LICENSE-2.0
//
//Unless required by applicable law or agreed to in writing, software
//distributed under the License is distributed on an "AS IS" BASIS,
//WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
//See the License for the specific language governing permissions and
//limitations under the License.
import Foundation
import Carbon
import IOKit
import IOKit.usb
import IOKit.hid


struct IOKeyEventMonitorContext {
  var lastSeenSender: String
  init(lastSeenSender: String) {
    self.lastSeenSender = lastSeenSender
  }
}

class IOKeyEventMonitor {
  private
  let hidManager: IOHIDManager
  let notificationCenter: CFNotificationCenter
  let match: CFMutableDictionary

  var lastActiveKeyboard: String = ""
  var kb2is: [String: TISInputSource] = [String: TISInputSource]()


  private class func createDeviceMatchingDictionary( usagePage: Int, usage: Int) -> CFMutableDictionary {
    let dict = [
      kIOHIDDeviceUsageKey: usage,
      kIOHIDDeviceUsagePageKey: usagePage
    ] as NSDictionary

    return dict.mutableCopy() as! NSMutableDictionary;
  }

  init? ( usagePage: Int, usage: Int) {
    hidManager = IOHIDManagerCreate( kCFAllocatorDefault, IOOptionBits(kIOHIDOptionsTypeNone));
    notificationCenter = CFNotificationCenterGetDistributedCenter();
    match = IOKeyEventMonitor.createDeviceMatchingDictionary(usagePage: usagePage, usage: usage);
    IOHIDManagerSetDeviceMatching( hidManager, match);
  }

  deinit {
    // FIXME find out how to pass nil as an IOKit.IOHIDValueCallback to unregister the callback
    let context = UnsafeMutableRawPointer(Unmanaged.passUnretained(self).toOpaque());
    //IOHIDManagerRegisterInputValueCallback( hidManager, nil , context);
    CFNotificationCenterRemoveObserver(notificationCenter, context, CFNotificationName(kTISNotifySelectedKeyboardInputSourceChanged), nil);
  }

  func restoreInputSource(keyboard: String) -> Void {
    if let targetIs = kb2is[keyboard] {
      //print("set input source to \(targetIs) for keyboard \(keyboard)");
      TISSelectInputSource(targetIs)
    } else {
      self.storeInputSource(keyboard: keyboard);
    }
  }

  func storeInputSource(keyboard: String) -> Void {
    let currentSource: TISInputSource = TISCopyCurrentKeyboardInputSource().takeUnretainedValue();
    kb2is[keyboard] = currentSource;
  }

  func onInputSourceChanged() -> Void {
    self.storeInputSource(keyboard: self.lastActiveKeyboard);
  }

  func onKeyboardEvent(keyboard: String) -> Void {
    if(self.lastActiveKeyboard != keyboard) {
      //print("Active keyboard changed from \(self.lastActiveKeyboard) to \(keyboard)");
      self.restoreInputSource(keyboard: keyboard);
      self.lastActiveKeyboard = keyboard;
    }
  }


  func start() -> Void {
    let context = UnsafeMutableRawPointer(Unmanaged.passUnretained(self).toOpaque());
    let myHIDKeyboardCallback: IOHIDValueCallback = {
      (context, ioreturn, sender, value) in
      let selfPtr = Unmanaged<IOKeyEventMonitor>.fromOpaque(context!).takeUnretainedValue();
      let senderDevice = Unmanaged<IOHIDDevice>.fromOpaque(sender!).takeUnretainedValue();

      let vendorId = String(describing: IOHIDDeviceGetProperty(senderDevice, kIOHIDVendorIDKey as CFString));
      let productId = String(describing: IOHIDDeviceGetProperty(senderDevice, kIOHIDProductIDKey as CFString));
      let product = String(describing: IOHIDDeviceGetProperty(senderDevice, kIOHIDProductKey as CFString));
      let keyboard = "\(product)[\(vendorId)-\(productId)]";
      selfPtr.onKeyboardEvent(keyboard: keyboard);

    }
    let inputSourceChanged: CFNotificationCallback = {
      (center, observer, name, notif, userInfo) in
      let selfPtr = Unmanaged<IOKeyEventMonitor>.fromOpaque(observer!).takeUnretainedValue();
      selfPtr.onInputSourceChanged()
    }

    CFNotificationCenterAddObserver(notificationCenter,
                                    context, inputSourceChanged,
                                    kTISNotifySelectedKeyboardInputSourceChanged, nil,
                                    CFNotificationSuspensionBehavior.deliverImmediately);


    IOHIDManagerRegisterInputValueCallback( hidManager, myHIDKeyboardCallback, context);
    IOHIDManagerScheduleWithRunLoop( hidManager, CFRunLoopGetMain(), CFRunLoopMode.defaultMode!.rawValue);
    IOHIDManagerOpen( hidManager, IOOptionBits(kIOHIDOptionsTypeNone));
  }

}

你怎么把这个改写成惯用的斯威夫特？特别是如何改进start()函数？

Answer 1

好吧，您编写的代码比许多已经滑动了一段时间的代码(可能包括我自己)都要好。所以，对于你的第一个节目，这是令人印象深刻的。

但是，对于我的口味来说，代码是有点麻烦的，也许还有几行空白行呢？还有，在一些地方跑得太远了.看看我是如何“包装”那些长功能婴儿车的。

另外，我发现一些挑剔的人：

括号一致性( x) (x) ( x )

功能声明间距不一致：

func x(){}

func y() {}


func z() {}

把:忘在fixme里

使用;

使用-> Void

//后无空格

在初始化器上不处于闭包时使用self

在自己的行中使用private，不确定是希望所有成员都是私有的，还是只希望第一个字段。(班级第一栏)

if(self.lastActiveKeyboard != keyboard)之间没有空隙吗？对于更复杂的语句，可以保存括号：if lastActiveKeyboard != keyboard {

为方便导航，没有// MARK:。我添加了一个，这样您就可以在属性+初始化器和函数之间快速跳转，因为您已经将它们分开了:)这是很好的！如果您还没有找到Show Document Items的键盘快捷方式，那么您将在列表中看到所有的FIXME:和MARK:。

错过了一种程序风格。在声明之前使用了storeInputSource .(在restore中)注意:这不是“必需的”，但它有助于您的逻辑流程(对您自己和读者)，但有时您将不得不打破这取决于您的风格。

闭包通常内联到in，与此有不一致之处。我只会把它换行，如果你通过第90栏。

不一致的闭合大括号} (有时有空行，有时没有空格)

没有注释或文档(从现在起一个月你会理解这个代码吗？)那些可能会看到它的人呢？或者你要求帮助的人？)

所以大部分都是挑剔的。对这段代码没什么特别不懂的。没有什么特别的原因，我想确保您了解guard，因为其中确实有一个if let语句，但是它是对if let的一个很好的使用。只是想确保你也知道警卫的事。

这是我对您的代码的快速重新起草，自从您问:P之后，我在start()中添加了我的个人触觉。

// Copyright [2016] Jean Helou
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

import Foundation
import Carbon
import IOKit
import IOKit.usb
import IOKit.hid


struct IOKeyEventMonitorContext {
  var lastSeenSender: String
  init(lastSeenSender: String) {
    self.lastSeenSender = lastSeenSender
  }
}

class IOKeyEventMonitor {
  private let hidManager: IOHIDManager

  let notificationCenter: CFNotificationCenter
  let match: CFMutableDictionary

  var lastActiveKeyboard: String = ""
  var kb2is: [String: TISInputSource] = [String: TISInputSource]()

  private class func createDeviceMatchingDictionary(usagePage: Int, usage: Int) -> CFMutableDictionary {
    let dict = [
      kIOHIDDeviceUsageKey: usage,
      kIOHIDDeviceUsagePageKey: usagePage
    ] as NSDictionary

    return dict.mutableCopy() as! NSMutableDictionary
  }

  init? (usagePage: Int, usage: Int) {
    hidManager = IOHIDManagerCreate(kCFAllocatorDefault, IOOptionBits(kIOHIDOptionsTypeNone))
    notificationCenter = CFNotificationCenterGetDistributedCenter()
    match = IOKeyEventMonitor.createDeviceMatchingDictionary(usagePage: usagePage, usage: usage)
    IOHIDManagerSetDeviceMatching( hidManager, match)
  }

  deinit {
    // FIXME: Find out how to pass nil as an IOKit.IOHIDValueCallback to unregister the callback
    let context = UnsafeMutableRawPointer(Unmanaged.passUnretained(self).toOpaque())
    // IOHIDManagerRegisterInputValueCallback( hidManager, nil , context)
    CFNotificationCenterRemoveObserver(notificationCenter,
                                       context,
                                       CFNotificationName(kTISNotifySelectedKeyboardInputSourceChanged),
                                       nil)
  }

// MARK: - Funcs:

  func storeInputSource(keyboard: String) {
    let currentSource: TISInputSource = TISCopyCurrentKeyboardInputSource().takeUnretainedValue();
    kb2is[keyboard] = currentSource
  }

  func restoreInputSource(keyboard: String) {
    if let targetIs = kb2is[keyboard] {
      // print("set input source to \(targetIs) for keyboard \(keyboard)")
      TISSelectInputSource(targetIs)
    } else {
      storeInputSource(keyboard: keyboard)
    }
  }

  func onInputSourceChanged() {
    storeInputSource(keyboard: self.lastActiveKeyboard);
  }

  func onKeyboardEvent(keyboard: String) {
    if lastActiveKeyboard != keyboard {
      // print("Active keyboard changed from \(self.lastActiveKeyboard) to \(keyboard)")
      restoreInputSource(keyboard: keyboard)
      lastActiveKeyboard = keyboard
    }
  }

  func start() {
    let context = UnsafeMutableRawPointer(Unmanaged.passUnretained(self).toOpaque())

    let myHIDKeyboardCallback: IOHIDValueCallback = { (context, ioreturn, sender, value) in

      let
      selfPtr      = Unmanaged<IOKeyEventMonitor>.fromOpaque(context!).takeUnretainedValue(),

      senderDevice = Unmanaged<IOHIDDevice>.fromOpaque(sender!).takeUnretainedValue(),

      vendorId     = String(describing: IOHIDDeviceGetProperty(senderDevice,
                                                               kIOHIDVendorIDKey  as CFString)),
      productId    = String(describing: IOHIDDeviceGetProperty(senderDevice,
                                                               kIOHIDProductIDKey as CFString)),
      product      = String(describing: IOHIDDeviceGetProperty(senderDevice,
                                                               kIOHIDProductKey   as CFString)),
      keyboard     = "\(product)[\(vendorId)-\(productId)]"

      selfPtr.onKeyboardEvent(keyboard: keyboard)
    }

    let inputSourceChanged: CFNotificationCallback = { (center, observer, name, notif, userInfo) in
      let selfPtr = Unmanaged<IOKeyEventMonitor>.fromOpaque(observer!).takeUnretainedValue()
      selfPtr.onInputSourceChanged()
    }

    CFNotificationCenterAddObserver(notificationCenter,
                                    context,
                                    inputSourceChanged,
                                    kTISNotifySelectedKeyboardInputSourceChanged,
                                    nil,
                                    CFNotificationSuspensionBehavior.deliverImmediately)

    IOHIDManagerRegisterInputValueCallback(hidManager, myHIDKeyboardCallback, context)
    IOHIDManagerScheduleWithRunLoop(hidManager, CFRunLoopGetMain(), CFRunLoopMode.defaultMode!.rawValue)
    IOHIDManagerOpen(hidManager, IOOptionBits(kIOHIDOptionsTypeNone))
  }
}

注意:由于导入，我无法编译它，所以我可能删除了一些太多的self (可能是在闭包中)，但我认为我没有.

我要做的另一件事是typealias一些长得离谱的IO /碳类型，这将有助于使事情更接近左边，并使链接具有一定的可读性。例如,

typealias CFNCGDC = CFNotificationCenterGetDistributedCenter
// Or:
typealias CFNCGetDistCenter = CFNotificationCenterGetDistributedCenter
// Or if it is a function:
extension CrazyCarbonClass {
  public func CFNSShortFunc(/* all the prams */) {
    CFNotificationCenterLongAsHellFunc(/* prams */)
  }
}

但这只是我的偏好。