如何在Xcode 7 beta 4中调用SecItemCopyMatching？

Question

在使用Swift的Xcode 6和7的早期版本中,这种语法可以工作:

    var secureItemValue: Unmanaged<AnyObject>?

    let statusCode: OSStatus = SecItemCopyMatching(keychainItemQuery, &secureItemValue)
    if statusCode == errSecSuccess
    {
        let opaquePointer = secureItemValue?.toOpaque()

        let secureItemValueData = Unmanaged<NSData>.fromOpaque(opaquePointer!).takeUnretainedValue()

        // Use secureItemValueData...
    }

但是,在Xcode 7 beta 4中,SecItemCopyMatching声明已更改:

旧: func SecItemCopyMatching(_ query: CFDictionary, _ result: UnsafeMutablePointer<AnyObject?>) -> OSStatus

新: func SecItemCopyMatching(_ query: CFDictionary!, _ result: UnsafeMutablePointer<Unmanaged<AnyObject>?>) -> OSStatus

...现在secureItemValue类型不匹配.

在提取结果之前,这个机制很混乱,我希望新声明在某种程度上更容易,但我不知道如何为secureItemValue变量声明正确的类型并提取结果.

Answer 1

这适用于Xcode 7 beta 4

var dataTypeRef: AnyObject?

    let status: OSStatus = withUnsafeMutablePointer(&dataTypeRef) { SecItemCopyMatching(keychainQuery as CFDictionaryRef, UnsafeMutablePointer($0)) }

    if status == noErr {
        return dataTypeRef as? NSData
    }
    else {
        return nil
    }