在swift中,NSObject的子类可以使用copy方法来复制实例对象，做法如下：
子类必须声明并实现NSCopying协议；
子类实现copyWithZone:方法；
子类的构造方法init必须使用requried关键字修饰
示例代码：
class ClazzA:NSObject,NSCopying {
var memberA = 0
// 必须使用required关键字修饰
required override init() {
}
// 实现copyWithZone方法
func copyWithZone(zone: NSZone)->AnyObject {
let theCopyObj = self.dynamicType.init()
theCopyObj.memberA = self.memberA
return theCopyObj
}
}
extension MTLCLFrame : NSCopying, NSMutableCopying {
public func copy(with zone: NSZone? = nil) -> Any {
let frame = MTLCLFrame()
frame.currentSampleTime = self.currentSampleTime
frame.orientation = self.orientation
frame.sampleBuffer = self.sampleBuffer
frame.image = self.image
MTLog(message: self.image)
MTLog(message: frame.image)
frame.sourceType = self.sourceType
frame.parameters = self.parameters
return frame
}
public func mutableCopy(with zone: NSZone? = nil) -> Any {
let frame = MTLCLFrame()
frame.currentSampleTime = self.currentSampleTime
frame.orientation = self.orientation
frame.sampleBuffer = self.sampleBuffer
frame.image = self.image
frame.sourceType = self.sourceType
frame.parameters = self.parameters
return frame
}
}
let currentFrame = frame.copy()
