Dev: implement invalidateAndCancel

Author: andriydruk

Foundation/URLSession/TaskRegistry.swift

@@ -86,6 +86,15 @@ extension URLSession._TaskRegistry {
             allTasksFinished()
         }
     }
+    
+    /// Cancel all tasks
+    ///
+    /// - Note: This must **only** be accessed on the owning session's work queue.
+    func cancelAllTasks() {
+        for (_, task) in self.tasks {
+            task._cancel()
+        }
+    }
 
     func notify(on tasksCompetion: @escaping () -> Void) {
         tasksFinishedCallback = tasksCompetion

Foundation/URLSession/URLSession.swift

@@ -316,7 +316,32 @@ open class URLSession : NSObject {
      * cancellation is subject to the state of the task, and some tasks may
      * have already have completed at the time they are sent -cancel.
      */
-    open func invalidateAndCancel() { NSUnimplemented() }
+    open func invalidateAndCancel() {
+        //we need to return immediately
+        workQueue.async {
+            
+            //don't allow creation of new tasks from this point onwards
+            self.invalidated = true
+            
+            let invalidateSessionCallback = { [weak self] in
+                //invoke the delegate method and break the delegate link
+                guard let `self` = self, let sessionDelegate = self.delegate else { return }
+                self.delegateQueue.addOperation {
+                    sessionDelegate.urlSession(self, didBecomeInvalidWithError: nil)
+                    self.delegate = nil
+                }
+            }
+            
+            //wait for running tasks to finish
+            if !self.taskRegistry.isEmpty {
+                self.taskRegistry.notify(on: invalidateSessionCallback)
+                self.taskRegistry.cancelAllTasks()
+            } else {
+                invalidateSessionCallback()
+            }
+        }
+        
+    }
 
     open func reset(completionHandler: @escaping () -> Void) { NSUnimplemented() } /* empty all cookies, cache and credential stores, removes disk files, issues -flushWithCompletionHandler:. Invokes completionHandler() on the delegate queue if not nil. */
 

Foundation/URLSession/URLSessionTask.swift

@@ -182,14 +182,7 @@ open class URLSessionTask : NSObject, NSCopying {
      */
     open func cancel() {
         workQueue.sync {
-            guard self.state == .running || self.state == .suspended else { return }
-            self.state = .canceling
-            self.workQueue.async {
-                let urlError = URLError(_nsError: NSError(domain: NSURLErrorDomain, code: NSURLErrorCancelled, userInfo: nil))
-                self.error = urlError
-                self._protocol?.stopLoading()
-                self._protocol?.client?.urlProtocol(self._protocol!, didFailWithError: urlError)
-            }
+            self._cancel()
         }
     }
 
@@ -305,6 +298,21 @@ open class URLSessionTask : NSObject, NSCopying {
     fileprivate var _priority: Float = URLSessionTask.defaultPriority
 }
 
+internal extension URLSessionTask {
+    
+    func _cancel() {
+        guard self.state == .running || self.state == .suspended else { return }
+        self.state = .canceling
+        self.workQueue.async {
+            let urlError = URLError(_nsError: NSError(domain: NSURLErrorDomain, code: NSURLErrorCancelled, userInfo: nil))
+            self.error = urlError
+            self._protocol?.stopLoading()
+            self._protocol?.client?.urlProtocol(self._protocol!, didFailWithError: urlError)
+        }
+    }
+    
+}
+
 extension URLSessionTask {
     public enum State : Int {
         /// The task is currently being serviced by the session