[3.1]Cherry picking URLProtocol implementation and refactoring URLSession

Foundation.xcodeproj/project.pbxproj

@@ -78,6 +78,7 @@
 		5B1FD9DE1D6D16580080E83C /* TaskRegistry.swift in Sources */ = {isa = PBXBuildFile; fileRef = 5B1FD9D21D6D16580080E83C /* TaskRegistry.swift */; };
 		5B1FD9DF1D6D16580080E83C /* TransferState.swift in Sources */ = {isa = PBXBuildFile; fileRef = 5B1FD9D31D6D16580080E83C /* TransferState.swift */; };
 		5B1FD9E11D6D178E0080E83C /* libcurl.3.dylib in Frameworks */ = {isa = PBXBuildFile; fileRef = 5B1FD9E01D6D178E0080E83C /* libcurl.3.dylib */; };
+                E429ED451E9638DA0031BC20 /* HTTPURLProtocol.swift in Sources */ = {isa = PBXBuildFile; fileRef = E429ED441E9638DA0031BC20 /* HTTPURLProtocol.swift */; };
 		5B1FD9E31D6D17B80080E83C /* TestNSURLSession.swift in Sources */ = {isa = PBXBuildFile; fileRef = 5B1FD9E21D6D17B80080E83C /* TestNSURLSession.swift */; };
 		5B23AB871CE62D17000DB898 /* Boxing.swift in Sources */ = {isa = PBXBuildFile; fileRef = 5B23AB861CE62D17000DB898 /* Boxing.swift */; };
 		5B23AB891CE62D4D000DB898 /* ReferenceConvertible.swift in Sources */ = {isa = PBXBuildFile; fileRef = 5B23AB881CE62D4D000DB898 /* ReferenceConvertible.swift */; };
@@ -495,6 +496,7 @@
 		5B1FD9D21D6D16580080E83C /* TaskRegistry.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = TaskRegistry.swift; sourceTree = "<group>"; };
 		5B1FD9D31D6D16580080E83C /* TransferState.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = TransferState.swift; sourceTree = "<group>"; };
 		5B1FD9E01D6D178E0080E83C /* libcurl.3.dylib */ = {isa = PBXFileReference; lastKnownFileType = "compiled.mach-o.dylib"; name = libcurl.3.dylib; path = usr/lib/libcurl.3.dylib; sourceTree = SDKROOT; };
+                E429ED441E9638DA0031BC20 /* HTTPURLProtocol.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; name = HTTPURLProtocol.swift;  path = HTTPURLProtocol.swift; sourceTree = "<group>"; };
 		5B1FD9E21D6D17B80080E83C /* TestNSURLSession.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = TestNSURLSession.swift; sourceTree = "<group>"; };
 		5B23AB861CE62D17000DB898 /* Boxing.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = Boxing.swift; sourceTree = "<group>"; };
 		5B23AB881CE62D4D000DB898 /* ReferenceConvertible.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = ReferenceConvertible.swift; sourceTree = "<group>"; };
@@ -928,23 +930,32 @@
 		5B1FD9C71D6D162D0080E83C /* Session */ = {
 			isa = PBXGroup;
 			children = (
+				E4F889331E9CF04D008A70EB /* http */,
 				5B1FD9C81D6D16580080E83C /* Configuration.swift */,
-				5B1FD9C91D6D16580080E83C /* EasyHandle.swift */,
-				5B1FD9CA1D6D16580080E83C /* HTTPBodySource.swift */,
-				5B1FD9CB1D6D16580080E83C /* HTTPMessage.swift */,
-				5B1FD9CC1D6D16580080E83C /* libcurlHelpers.swift */,
-				5B1FD9CD1D6D16580080E83C /* MultiHandle.swift */,
 				5B1FD9CE1D6D16580080E83C /* NSURLSession.swift */,
 				5B1FD9CF1D6D16580080E83C /* NSURLSessionConfiguration.swift */,
 				5B1FD9D01D6D16580080E83C /* NSURLSessionDelegate.swift */,
 				5B1FD9D11D6D16580080E83C /* NSURLSessionTask.swift */,
 				5B1FD9D21D6D16580080E83C /* TaskRegistry.swift */,
-				5B1FD9D31D6D16580080E83C /* TransferState.swift */,
 			);
 			name = Session;
 			path = NSURLSession;
 			sourceTree = "<group>";
 		};
+		E4F889331E9CF04D008A70EB /* http */ = {
+			isa = PBXGroup;
+			children = (
+				E429ED441E9638DA0031BC20 /* HTTPURLProtocol.swift */,
+				5B1FD9C91D6D16580080E83C /* EasyHandle.swift */,
+                                5B1FD9CA1D6D16580080E83C /* HTTPBodySource.swift */,
+                                5B1FD9CB1D6D16580080E83C /* HTTPMessage.swift */,
+                                5B1FD9CC1D6D16580080E83C /* libcurlHelpers.swift */,
+                                5B1FD9CD1D6D16580080E83C /* MultiHandle.swift */,
+                                5B1FD9D31D6D16580080E83C /* TransferState.swift */,
+                        );
+                        name = http;
+                        sourceTree = "<group>";
+                };
 		5B5D88531BBC938800234F36 = {
 			isa = PBXGroup;
 			children = (
@@ -2040,6 +2051,7 @@
 				5B23AB871CE62D17000DB898 /* Boxing.swift in Sources */,
 				5BF7AEA41BCD51F9008F214A /* Bundle.swift in Sources */,
 				5B23AB891CE62D4D000DB898 /* ReferenceConvertible.swift in Sources */,
+				E429ED451E9638DA0031BC20 /* HTTPURLProtocol.swift in Sources */,
 				D3E8D6D11C367AB600295652 /* NSSpecialValue.swift in Sources */,
 				5B1FD9D51D6D16580080E83C /* EasyHandle.swift in Sources */,
 				EAB57B721BD1C7A5004AC5C5 /* NSPortMessage.swift in Sources */,

Foundation/NSURLProtocol.swift

@@ -7,6 +7,9 @@
 // See http://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
 //
 
+import CoreFoundation
+import Dispatch
+
 /*!
     @header NSURLProtocol.h
 
@@ -142,6 +145,96 @@ public protocol URLProtocolClient : NSObjectProtocol {
     func urlProtocol(_ protocol: URLProtocol, didCancel challenge: URLAuthenticationChallenge)
 }
 
+internal class _ProtocolClient : NSObject, URLProtocolClient {
+
+    func urlProtocol(_ protocol: URLProtocol, didReceive response: URLResponse, cacheStoragePolicy policy: URLCache.StoragePolicy) {
+        `protocol`.task?.response = response
+    }
+
+    func urlProtocolDidFinishLoading(_ protocol: URLProtocol) {
+        guard let task = `protocol`.task else { fatalError() }
+        guard let session = task.session as? URLSession else { fatalError() }
+        switch session.behaviour(for: task) {
+        case .taskDelegate(let delegate):
+            guard let s = session as? URLSession else { fatalError() }
+            s.delegateQueue.addOperation {
+                delegate.urlSession(s, task: task, didCompleteWithError: nil)
+                task.state = .completed
+            }
+        case .noDelegate:
+            task.state = .completed
+        case .dataCompletionHandler(let completion):
+            let data = Data()
+            guard let client = `protocol`.client else { fatalError() }
+            client.urlProtocol(`protocol`, didLoad: data)
+            return
+        case .downloadCompletionHandler(let completion):
+            guard let s = session as? URLSession else { fatalError() }
+            s.delegateQueue.addOperation {
+                completion(task.currentRequest?.url, task.response, nil)
+                task.state = .completed
+            }
+        }
+    }
+
+    func urlProtocol(_ protocol: URLProtocol, didCancel challenge: URLAuthenticationChallenge) {
+        NSUnimplemented()
+    }
+
+    func urlProtocol(_ protocol: URLProtocol, didReceive challenge: URLAuthenticationChallenge) {
+        NSUnimplemented()
+    }
+
+    func urlProtocol(_ protocol: URLProtocol, didLoad data: Data) {
+        guard let task = `protocol`.task else { fatalError() }
+        guard let session = task.session as? URLSession else { fatalError() }
+        switch session.behaviour(for: task) {
+        case .dataCompletionHandler(let completion):
+            guard let s = task.session as? URLSession else { fatalError() }
+            s.delegateQueue.addOperation {
+                completion(data, task.response, nil)
+                task.state = .completed
+            }
+        default: return
+        }
+    }
+
+    func urlProtocol(_ protocol: URLProtocol, didFailWithError error: Error) {
+        guard let task = `protocol`.task else { fatalError() }
+        guard let session = task.session as? URLSession else { fatalError() }
+        switch session.behaviour(for: task) {
+        case .taskDelegate(let delegate):
+            guard let s = session as? URLSession else { fatalError() }
+            s.delegateQueue.addOperation {
+                delegate.urlSession(s, task: task, didCompleteWithError: error as Error)
+                task.state = .completed
+            }
+        case .noDelegate:
+            task.state = .completed
+        case .dataCompletionHandler(let completion):
+            guard let s = session as? URLSession else { fatalError() }
+            s.delegateQueue.addOperation {
+                completion(nil, nil, error)
+                task.state = .completed
+            }
+        case .downloadCompletionHandler(let completion):
+            guard let s = session as? URLSession else { fatalError() }
+            s.delegateQueue.addOperation {
+                completion(nil, nil, error)
+                task.state = .completed
+            }
+        }
+    }
+
+    func urlProtocol(_ protocol: URLProtocol, cachedResponseIsValid cachedResponse: CachedURLResponse) {
+        NSUnimplemented()
+    }
+
+    func urlProtocol(_ protocol: URLProtocol, wasRedirectedTo request: URLRequest, redirectResponse: URLResponse) {
+        NSUnimplemented()
+    }
+}
+
 /*!
     @class NSURLProtocol
 
@@ -151,7 +244,9 @@ public protocol URLProtocolClient : NSObjectProtocol {
     or more protocols or URL schemes.
 */
 open class URLProtocol : NSObject {
-
+
+    private static var _registeredProtocolClasses = [AnyClass]()
+    private static var _classesLock = NSLock()
     /*! 
         @method initWithRequest:cachedResponse:client:
         @abstract Initializes an NSURLProtocol given request, 
@@ -165,28 +260,43 @@ open class URLProtocol : NSObject {
         interface the protocol implementation can use to report results back
         to the URL loading system.
     */
-    public init(request: URLRequest, cachedResponse: CachedURLResponse?, client: URLProtocolClient?) { NSUnimplemented() }
-
+    public required init(request: URLRequest, cachedResponse: CachedURLResponse?, client: URLProtocolClient?) {
+        self._request = request
+        self._cachedResponse = cachedResponse
+        self._client = client ?? _ProtocolClient()
+    }
+
+    private var _request : URLRequest
+    private var _cachedResponse : CachedURLResponse?
+    private var _client : URLProtocolClient?
+
     /*! 
         @method client
         @abstract Returns the NSURLProtocolClient of the receiver. 
         @result The NSURLProtocolClient of the receiver.  
     */
-    open var client: URLProtocolClient? { NSUnimplemented() }
+    open var client: URLProtocolClient? {
+        set { self._client = newValue }
+        get { return self._client }
+    }
 
     /*! 
         @method request
         @abstract Returns the NSURLRequest of the receiver. 
         @result The NSURLRequest of the receiver. 
     */
-    /*@NSCopying*/ open var request: URLRequest { NSUnimplemented() }
+    /*@NSCopying*/ open var request: URLRequest {
+        return _request
+     }
 
     /*! 
         @method cachedResponse
         @abstract Returns the NSCachedURLResponse of the receiver.  
         @result The NSCachedURLResponse of the receiver. 
     */
-    /*@NSCopying*/ open var cachedResponse: CachedURLResponse? { NSUnimplemented() }
+    /*@NSCopying*/ open var cachedResponse: CachedURLResponse? {
+        return _cachedResponse
+     }
 
     /*======================================================================
       Begin responsibilities for protocol implementors
@@ -207,7 +317,9 @@ open class URLProtocol : NSObject {
         @param request A request to inspect.
         @result YES if the protocol can handle the given request, NO if not.
     */
-    open class func canInit(with request: URLRequest) -> Bool { NSUnimplemented() }
+    open class func canInit(with request: URLRequest) -> Bool {
+        NSRequiresConcreteImplementation()
+    }
 
     /*! 
         @method canonicalRequestForRequest:
@@ -246,7 +358,9 @@ open class URLProtocol : NSObject {
         @discussion When this method is called, the protocol implementation
         should start loading a request.
     */
-    open func startLoading() { NSUnimplemented() }
+    open func startLoading() {
+        NSRequiresConcreteImplementation()
+    }
 
     /*! 
         @method stopLoading
@@ -256,7 +370,9 @@ open class URLProtocol : NSObject {
         to a cancel operation, so protocol implementations must be able to
         handle this call while a load is in progress.
     */
-    open func stopLoading() { NSUnimplemented() }
+    open func stopLoading() {
+        NSRequiresConcreteImplementation()
+    }
 
     /*======================================================================
       End responsibilities for protocol implementors
@@ -323,19 +439,65 @@ open class URLProtocol : NSObject {
         The only way that failure can occur is if the given class is not a
         subclass of NSURLProtocol.
     */
-    open class func registerClass(_ protocolClass: AnyClass) -> Bool { NSUnimplemented() }
-
+    open class func registerClass(_ protocolClass: AnyClass) -> Bool {
+        if protocolClass is URLProtocol.Type {
+            _classesLock.lock()
+            guard !_registeredProtocolClasses.contains(where: { $0 === protocolClass }) else {
+                _classesLock.unlock()
+                return true
+            }
+            _registeredProtocolClasses.append(protocolClass)
+            _classesLock.unlock()
+            return true
+        }
+        return false
+    }
+
+    internal class func getProtocolClass(protocols: [AnyClass], request: URLRequest) -> AnyClass? {
+        // Registered protocols are consulted in reverse order.
+        // This behaviour makes the latest registered protocol to be consulted first
+        _classesLock.lock()
+        let protocolClasses = protocols
+        for protocolClass in protocolClasses {
+            let urlProtocolClass: AnyClass = protocolClass
+            guard let urlProtocol = urlProtocolClass as? URLProtocol.Type else { fatalError() }
+            if urlProtocol.canInit(with: request) {
+                _classesLock.unlock()
+                return urlProtocol
+            }
+        }
+        _classesLock.unlock()
+        return nil
+    }
+
+    internal class func getProtocols() -> [AnyClass]? {
+        return _registeredProtocolClasses
+    }
     /*! 
         @method unregisterClass:
         @abstract This method unregisters a protocol. 
         @discussion After unregistration, a protocol class is no longer
         consulted in calls to NSURLProtocol class methods.
         @param protocolClass The class to unregister.
     */
-    open class func unregisterClass(_ protocolClass: AnyClass) { NSUnimplemented() }
+    open class func unregisterClass(_ protocolClass: AnyClass) {
+        _classesLock.lock()
+        if let idx = _registeredProtocolClasses.index(where: { $0 === protocolClass }) {
+            _registeredProtocolClasses.remove(at: idx)
+        }
+        _classesLock.unlock()
+    }
 
     open class func canInit(with task: URLSessionTask) -> Bool { NSUnimplemented() }
-    public convenience init(task: URLSessionTask, cachedResponse: CachedURLResponse?, client: URLProtocolClient?) { NSUnimplemented() }
-    /*@NSCopying*/ open var task: URLSessionTask? { NSUnimplemented() }
-}
+    public required convenience init(task: URLSessionTask, cachedResponse: CachedURLResponse?, client: URLProtocolClient?) {
+        let urlRequest = task.originalRequest
+        self.init(request: urlRequest!, cachedResponse: cachedResponse, client: client)
+        self.task = task
+    }
+    /*@NSCopying*/ open var task: URLSessionTask? {
+        set { self._task = newValue }
+        get { return self._task }
+    }
 
+    private var _task : URLSessionTask? = nil
+}

Foundation/NSURLSession/NSURLSession.swift

@@ -221,6 +221,8 @@ open class URLSession : NSObject {
         let c = URLSession._Configuration(URLSessionConfiguration: configuration)
         self._configuration = c
         self.multiHandle = _MultiHandle(configuration: c, workQueue: workQueue)
+        // registering all the protocol classes with URLProtocol
+        let _ = URLProtocol.registerClass(_HTTPURLProtocol.self)
     }
 
     /*
@@ -246,6 +248,8 @@ open class URLSession : NSObject {
         let c = URLSession._Configuration(URLSessionConfiguration: configuration)
         self._configuration = c
         self.multiHandle = _MultiHandle(configuration: c, workQueue: workQueue)
+        // registering all the protocol classes with URLProtocol
+        let _ = URLProtocol.registerClass(_HTTPURLProtocol.self)
     }
 
     open let delegateQueue: OperationQueue