I am porting an App from Objective-C to Swift and I need to use the following method:
CFStreamCreatePairWithSocketToHost(alloc: CFAllocator!, host: CFString!, port: UInt32, \
readStream: CMutablePointer<Unmanaged<CFReadStream>?>, \
writeStream: CMutablePointer<Unmanaged<CFWriteStream>?>)
The old logic looks like this (which several web sites seem to agree on):
CFReadStreamRef readStream = NULL;
CFWriteStreamRef writeStream = NULL;
CFStreamCreatePairWithSocketToHost(NULL, (__bridge CFStringRef)(host), port, \
&readStream, &writeStream);
NSInputStream inputStream = (__bridge_transfer NSInputStream *)readStream;
NSOutputStream outputStream = (__bridge_transfer NSOutputStream *)writeStream;
Which works fine thanks to toll-free bridging. However, ARC does not exist in "Swift-space", and the type system has changed.
How do I turn my streams into instances of
CMutablePointer<Unmanaged<CFReadStream>?>, and
CMutablePointer<Unmanaged<CFWriteStream>?>
And then convert them back into NSStream
subclasses after the CFStreamCreatePairWithSocketToHost
call?
I got it to work, here's my code: Make sure you keep a reference of the connection class somewhere :-)
class Connection : NSObject, NSStreamDelegate {
let serverAddress: CFString = "127.0.0.1"
let serverPort: UInt32 = 8443
private var inputStream: NSInputStream!
private var outputStream: NSOutputStream!
func connect() {
println("connecting...")
var readStream: Unmanaged<CFReadStream>?
var writeStream: Unmanaged<CFWriteStream>?
CFStreamCreatePairWithSocketToHost(nil, self.serverAddress, self.serverPort, &readStream, &writeStream)
// Documentation suggests readStream and writeStream can be assumed to
// be non-nil. If you believe otherwise, you can test if either is nil
// and implement whatever error-handling you wish.
self.inputStream = readStream!.takeRetainedValue()
self.outputStream = writeStream!.takeRetainedValue()
self.inputStream.delegate = self
self.outputStream.delegate = self
self.inputStream.scheduleInRunLoop(NSRunLoop.currentRunLoop(), forMode: NSDefaultRunLoopMode)
self.outputStream.scheduleInRunLoop(NSRunLoop.currentRunLoop(), forMode: NSDefaultRunLoopMode)
self.inputStream.open()
self.outputStream.open()
}
func stream(stream: NSStream, handleEvent eventCode: NSStreamEvent) {
println("stream event")
}
}
I wasn't able to get the examples others have provided in this thread to work. Sure, they compiled, but they crashed as soon as the connection was open.
However, I noticed in the WWDC 2014 discussions (and iOS 8 release notes) that there is a new method for initializing an NSStream for creating a bound pair of in/out streams.
See below:
var inputStream: NSInputStream?
var outputStream: NSOutputStream?
NSStream.getStreamsToHostWithName("localhost", port: 1234, inputStream: &inputStream, outputStream: &outputStream)
This removes the need for the awkward CFStreamCreatePairWithSocketToHost call as well as removing the need for Unmanaged resources.
I worked out how to do it. A few important notes:
CMutablePointers
will be automatically created if you use the & operator.- You can get at the
T
in anUnmanaged<T>
with.getUnretainedValue()
andgetRetainedValue()
(Seems.getUnretainedValue()
is analogous to__bridge_transfer
) - Optionals are automatically initialised to
nil
. - If an optional is
nil
it will translate into afalse
condition.
So far I have (untested):
var readStream: Unmanaged<CFReadStream>?
var writeStream: Unmanaged<CFWriteStream>?
CFStreamCreatePairWithSocketToHost(kCFAllocatorDefault, host, port, \
&readStream, &writeStream)
if (readStream && writeStream) {
inputStream = readStream!.takeUnretainedValue();
outputStream = writeStream!.takeUnretainedValue();
}
I am using getStreamsToHostWithName function of NSStream class. It is more easy and beeter than CFStreamCreatePairWithSocketToHost
func initNetworkCommunication() {
print("connecting...")
let serverAddress = "gzoa.vps.infomaniak.com"
let serverPort = 1234
NSStream.getStreamsToHostWithName(serverAddress, port: serverPort, inputStream: &inputStream, outputStream: &outputStream)
self.inputStream!.delegate = self
self.outputStream!.delegate = self
self.inputStream!.scheduleInRunLoop(NSRunLoop.currentRunLoop(), forMode: NSDefaultRunLoopMode)
self.outputStream!.scheduleInRunLoop(NSRunLoop.currentRunLoop(), forMode: NSDefaultRunLoopMode)
self.inputStream!.open()
self.outputStream!.open()
}
Swift 3 version of CF and NS code. Both work for me.
CF:
class Connection: NSObject, StreamDelegate {
private var inputStream: InputStream!
private var outputStream: OutputStream!
var connected = false
func connect(host: String, port: UInt32) {
var readStream: Unmanaged<CFReadStream>?
var writeStream: Unmanaged<CFWriteStream>?
CFStreamCreatePairWithSocketToHost(nil, host as CFString, port, &readStream, &writeStream)
self.inputStream = readStream!.takeRetainedValue()
self.outputStream = writeStream!.takeRetainedValue()
if let inputStream = inputStream, let outputStream = outputStream {
inputStream.delegate = self
outputStream.delegate = self
inputStream.schedule(in: RunLoop.current, forMode: RunLoopMode.defaultRunLoopMode)
outputStream.schedule(in: RunLoop.current, forMode: RunLoopMode.defaultRunLoopMode)
inputStream.open()
outputStream.open()
connected = true
}
}
func stream(_ aStream: Stream, handle eventCode: Stream.Event) {
print("stream event, \(eventCode)")
}
}
NS:
class NSConnection: NSObject, StreamDelegate {
private var inputStream: InputStream?
private var outputStream: OutputStream?
var connected = false
func connect(host: String, port: Int) {
Stream.getStreamsToHost(withName: host, port: port, inputStream: &inputStream, outputStream: &outputStream)
if let inputStream = inputStream, let outputStream = outputStream {
inputStream.delegate = self
outputStream.delegate = self
inputStream.schedule(in: RunLoop.current, forMode: RunLoopMode.defaultRunLoopMode)
outputStream.schedule(in: RunLoop.current, forMode: RunLoopMode.defaultRunLoopMode)
inputStream.open()
outputStream.open()
}
}
func stream(_ aStream: Stream, handle eventCode: Stream.Event) {
print("stream event, \(eventCode)")
}
}
来源:https://stackoverflow.com/questions/24028995/toll-free-bridging-and-pointer-access-in-swift