Merge pull request #31 from davedelong/master

Add a cancellation callback to OperationObserver
pluralsight · Nov 25, 2015 · c4d70c2 · c4d70c2
2 parents d3cf964 + 3e84556
commit c4d70c2
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Showing 7 changed files with 34 additions and 13 deletions.
diff --git a/PSOperations/BlockObserver.swift b/PSOperations/BlockObserver.swift
@@ -16,11 +16,13 @@ public struct BlockObserver: OperationObserver {
     // MARK: Properties
 
     private let startHandler: (Operation -> Void)?
+    private let cancelHandler: (Operation -> Void)?
     private let produceHandler: ((Operation, NSOperation) -> Void)?
     private let finishHandler: ((Operation, [NSError]) -> Void)?
 
-    public init(startHandler: (Operation -> Void)? = nil, produceHandler: ((Operation, NSOperation) -> Void)? = nil, finishHandler: ((Operation, [NSError]) -> Void)? = nil) {
+    public init(startHandler: (Operation -> Void)? = nil, cancelHandler: (Operation -> Void)? = nil, produceHandler: ((Operation, NSOperation) -> Void)? = nil, finishHandler: ((Operation, [NSError]) -> Void)? = nil) {
         self.startHandler = startHandler
+        self.cancelHandler = cancelHandler
         self.produceHandler = produceHandler
         self.finishHandler = finishHandler
     }
@@ -31,6 +33,10 @@ public struct BlockObserver: OperationObserver {
         startHandler?(operation)
     }
 
+    public func operationDidCancel(operation: Operation) {
+        cancelHandler?(operation)
+    }
+
     public func operation(operation: Operation, didProduceOperation newOperation: NSOperation) {
         produceHandler?(operation, newOperation)
     }

diff --git a/PSOperations/LocationOperation.swift b/PSOperations/LocationOperation.swift
@@ -32,6 +32,11 @@ public class LocationOperation: Operation, CLLocationManagerDelegate {
         super.init()
         addCondition(LocationCondition(usage: .WhenInUse))
         addCondition(MutuallyExclusive<CLLocationManager>())
+        addObserver(BlockObserver(cancelHandler: { [weak self] _ in
+            dispatch_async(dispatch_get_main_queue()) {
+                self?.stopLocationUpdates()
+            }
+        }))
     }
 
     override public func execute() {
@@ -56,13 +61,6 @@ public class LocationOperation: Operation, CLLocationManagerDelegate {
         }
     }
 
-    override public func cancel() {
-        dispatch_async(dispatch_get_main_queue()) {
-            self.stopLocationUpdates()
-            super.cancel()
-        }
-    }
-
     private func stopLocationUpdates() {
         manager?.stopUpdatingLocation()
         manager = nil

diff --git a/PSOperations/Operation.swift b/PSOperations/Operation.swift
@@ -203,6 +203,13 @@ public class Operation: NSOperation {
 
         didSet {
             didChangeValueForKey("cancelledState")
+            if _cancelled != oldValue && _cancelled == true {
+
+                for observer in observers {
+                    observer.operationDidCancel(self)
+                }
+
+            }
         }
     }
 

diff --git a/PSOperations/OperationObserver.swift b/PSOperations/OperationObserver.swift
@@ -17,6 +17,9 @@ public protocol OperationObserver {
     /// Invoked immediately prior to the `Operation`'s `execute()` method.
     func operationDidStart(operation: Operation)
 
+    /// Invoked immediately after the first time the `Operation`'s `cancel()` method is called
+    func operationDidCancel(operation: Operation)
+
     /// Invoked when `Operation.produceOperation(_:)` is executed.
     func operation(operation: Operation, didProduceOperation newOperation: NSOperation)
 

diff --git a/PSOperations/TimeoutObserver.swift b/PSOperations/TimeoutObserver.swift
@@ -45,6 +45,10 @@ public struct TimeoutObserver: OperationObserver {
             }
         }
     }
+
+    public func operationDidCancel(operation: Operation) {
+        // No op.
+    }
 
     public func operation(operation: Operation, didProduceOperation newOperation: NSOperation) {
         // No op.

diff --git a/PSOperations/URLSessionTaskOperation.swift b/PSOperations/URLSessionTaskOperation.swift
@@ -31,6 +31,10 @@ public class URLSessionTaskOperation: Operation {
         assert(task.state == .Suspended, "Tasks must be suspended.")
         self.task = task
         super.init()
+
+        addObserver(BlockObserver(cancelHandler: { _ in
+            task.cancel()
+        }))
     }
 
     override public func execute() {
@@ -59,9 +63,4 @@ public class URLSessionTaskOperation: Operation {
             }
         }
     }
-
-    override public func cancel() {
-        task.cancel()
-        super.cancel()
-    }
 }
diff --git a/PSOperationsTests/PSOperationsTests.swift b/PSOperationsTests/PSOperationsTests.swift
@@ -51,6 +51,10 @@ class TestObserver: OperationObserver {
 
     }
 
+    func operationDidCancel(operation: Operation) {
+
+    }
+
     func operationDidFinish(operation: Operation, errors: [NSError]) {
         finished = true
         self.errors = errors