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インスタンスをUnsafeMutablePointerに変換して扱う

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CTRunDelegateRefを扱う上でインスタンスをUnsafeMutablePointerにする必要がある部分がでてきたので、下記の方法だとアプリもクラッシュせずエラーも出ずに動いたので書き残します。

let originalView = UIView()
print(originalView) //"UIView: 0x7fcd29f031a0"

//UnsafeMutablePointerに変換
let pointer = UnsafeMutablePointer<UIView>(Unmanaged.passRetained(originalView).toOpaque())

//UIView取得
let takeValue = Unmanaged<UIView>.fromOpaque(COpaquePointer(pointer)).takeRetainedValue()

print(takeValue) //"UIView: 0x7fcd29f031a0"
Sample
extension UIView {
    class func view(pointer pointer: UnsafeMutablePointer<Void>) -> UIView {
        return Unmanaged<UIView>.fromOpaque(COpaquePointer(pointer)).takeRetainedValue()
    }
}

class HogeView: UIView {
    func  createWidthCallback() -> CTRunDelegateGetWidthCallback {
        return {
            let view = UIView.view(pointer: $0)
            return view.bounds.size.width
        }
    }
}

CTRunDelegateGetWidthCallbackなどのtypealias@convention(c)が付加されているものでも、staticなメソッドでpointerから自身を取得するようにすればエラーは起こらなくなります。
逆にselfにアクセスするとエラーが起こります。

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