Handling SecRequestSharedWebCredential that works with Xcode 7.2 and Swift 2.

SecRequestSharedWebCredential.swift

SecRequestSharedWebCredential(nil, nil) { credentials, error in
    guard error == nil else {
        let cocoaError = error! as NSError
        let errorIsExpected = cocoaError.domain == NSOSStatusErrorDomain && cocoaError.code == Int(errSecItemNotFound)
        
        if !errorIsExpected {
            // Do something with an unexpected error.
        }
        
        return
    }

    guard let credentials = credentials where CFArrayGetCount(credentials) > 0 else {
        // Did not find a shared web credential.
        return
    }

    guard CFArrayGetCount(credentials) == 1 else {
        // There should be exactly one credential.
        return
    }

    let unsafeCredential = CFArrayGetValueAtIndex(credentials, 0)
    let credential = unsafeBitCast(unsafeCredential, CFDictionaryRef.self)

    let unsafeAccount = CFDictionaryGetValue(credential, unsafeAddressOf(kSecAttrAccount))
    let account = unsafeBitCast(unsafeAccount, CFString.self) as String

    let unsafePassword = CFDictionaryGetValue(credential, unsafeAddressOf(kSecSharedPassword))
    let password = unsafeBitCast(unsafePassword, CFString.self) as String

    print("Found \(account) with \(password).")
}