Question

我熟悉Obj-c并熟悉Swift，但是我正在为Swift非常严格的类型检查而苦苦挣扎。举个例子，我想做的就是转换下面的Obj-c中的例程：

- (void)receiveIncomingConnectionNotification:(NSNotification *)notification {
    NSDictionary *userInfo = [notification userInfo];
    NSFileHandle *incomingFileHandle = [userInfo objectForKey:NSFileHandleNotificationFileHandleItem];

    if (incomingFileHandle) {
        CFDictionaryAddValue(
            incomingRequests,
            (__bridge const void *)(incomingFileHandle),
            (__bridge const void *)((__bridge id)CFHTTPMessageCreateEmpty(kCFAllocatorDefault, TRUE)));
    }
}

Swift：

func receiveIncomingConnectionNotification(notification: NSNotification) {
    let userInfo: NSDictionary = notification.userInfo!
    let incomingFileHandle: NSFileHandle? = userInfo.objectForKey(NSFileHandleNotificationFileHandleItem) as? NSFileHandle
    if (incomingFileHandle != nil) {
        CFDictionaryAddValue(self.incomingRequests as CFMutableDictionaryRef, incomingFileHandle, CFHTTPMessageCreateEmpty(kCFAllocatorDefault, true))
    }
}

但CFDictionaryAddValue调用一直产生错误，指向“true”参数，表示“Cannot convert the expression's type '(CFMutableDictionaryRef, NSFileHandle?, Unmanaged<CFHTTPMessage>!' to type BooleanLiteralConvertible!。

任何人都知道正确的方法，或者BooleanLiteralConvertible是什么？

Answer 1

如果你一次考虑一个论点，那就更清楚了：

let m = CFHTTPMessageCreateEmpty(kCFAllocatorDefault, 1).takeRetainedValue()
let f = incomingFileHandle!
let d = self.incomingRequests as CFMutableDictionaryRef
CFDictionaryAddValue(d, unsafeAddressOf(f), unsafeAddressOf(m))

C布尔值必须表示为数字。
CFHTTPMessageCreateEmpty需要内存管理，因为它以非托管方式返回。
您的incomingFileHandle是可选的;它需要展开。
CFDictionaryAddValue需要不安全的地址（UnsafePointer）。

从Swift调用Core-Foundation方法

1 个答案: