'Cancel' for PromiseKit

Cartfile

@@ -1 +1,2 @@
-github "mxcl/PromiseKit" ~> 6.0
+#github "mxcl/PromiseKit" ~> 6.0
+github "dougzilla32/PromiseKit" "CoreCancel"

Cartfile.resolved

@@ -1 +1 @@
-github "mxcl/PromiseKit" "6.3.4"
+github "dougzilla32/PromiseKit" "087b3cf470890ff9ea841212e2f3e285fecf3988"

Sources/MKDirections+Promise.swift

@@ -1,38 +1,64 @@
-import MapKit
-#if !PMKCocoaPods
-import PromiseKit
-#endif
-
-/**
- To import the `MKDirections` category:
-
-    use_frameworks!
-    pod "PromiseKit/MapKit"
-
- And then in your sources:
-
-    import PromiseKit
-*/
-extension MKDirections {
-#if swift(>=4.2)
-    /// Begins calculating the requested route information asynchronously.
-    public func calculate() -> Promise<Response> {
-        return Promise { calculate(completionHandler: $0.resolve) }
-    }
-
-    /// Begins calculating the requested travel-time information asynchronously.
-    public func calculateETA() -> Promise<ETAResponse> {
-        return Promise { calculateETA(completionHandler: $0.resolve) }
-    }
-#else
-    /// Begins calculating the requested route information asynchronously.
-    public func calculate() -> Promise<MKDirectionsResponse> {
-        return Promise { calculate(completionHandler: $0.resolve) }
-    }
-
-    /// Begins calculating the requested travel-time information asynchronously.
-    public func calculateETA() -> Promise<MKETAResponse> {
-        return Promise { calculateETA(completionHandler: $0.resolve) }
-    }
-#endif
-}
+import MapKit
+#if !PMKCocoaPods
+import PromiseKit
+#endif
+
+/**
+ To import the `MKDirections` category:
+
+    use_frameworks!
+    pod "PromiseKit/MapKit"
+
+ And then in your sources:
+
+    import PromiseKit
+*/
+extension MKDirections {
+#if swift(>=4.2)
+    /// Begins calculating the requested route information asynchronously.
+    /// - Note: cancelling this promise will cancel the underlying task
+    /// - SeeAlso: [Cancellation](http://promisekit.org/docs/)
+    public func calculate() -> Promise<Response> {
+        return Promise<Response>(cancellableTask: MKDirectionsTask(self)) { calculate(completionHandler: $0.resolve) }
+    }
+
+    /// Begins calculating the requested travel-time information asynchronously.
+    /// - Note: cancelling this promise will cancel the underlying task
+    /// - SeeAlso: [Cancellation](http://promisekit.org/docs/)
+    public func calculateETA() -> Promise<ETAResponse> {
+        return Promise<ETAResponse>(cancellableTask: MKDirectionsTask(self)) { calculateETA(completionHandler: $0.resolve) }
+    }
+#else
+    /// Begins calculating the requested route information asynchronously.
+    /// - Note: cancelling this promise will cancel the underlying task
+    /// - SeeAlso: [Cancellation](http://promisekit.org/docs/)
+    public func calculate() -> Promise<MKDirectionsResponse> {
+        return Promise<MKDirectionsResponse>(cancellableTask: MKDirectionsTask(self)) { calculate(completionHandler: $0.resolve) }
+    }
+
+    /// Begins calculating the requested travel-time information asynchronously.
+    /// - Note: cancelling this promise will cancel the underlying task
+    /// - SeeAlso: [Cancellation](http://promisekit.org/docs/)
+    public func calculateETA() -> Promise<MKETAResponse> {
+        return Promise<MKETAResponse>(cancellableTask: MKDirectionsTask(self)) { calculateETA(completionHandler: $0.resolve) }
+    }
+#endif
+}
+
+private class MKDirectionsTask: CancellableTask {
+    let directions: MKDirections
+    var cancelAttempted = false
+
+    init(_ directions: MKDirections) {
+        self.directions = directions
+    }
+
+    func cancel() {
+        directions.cancel()
+        cancelAttempted = true
+    }
+
+    var isCancelled: Bool {
+        return cancelAttempted && !directions.isCalculating
+    }
+}

Sources/MKMapSnapshotter+Promise.swift

@@ -1,28 +1,50 @@
-import MapKit
-#if !PMKCocoaPods
-import PromiseKit
-#endif
-
-/**
- To import the `MKMapSnapshotter` category:
-
-    use_frameworks!
-    pod "PromiseKit/MapKit"
-
- And then in your sources:
-
-    import PromiseKit
-*/
-extension MKMapSnapshotter {
-#if swift(>=4.2)
-    /// Starts generating the snapshot using the options set in this object.
-    public func start() -> Promise<Snapshot> {
-        return Promise { start(completionHandler: $0.resolve) }
-    }
-#else
-    /// Starts generating the snapshot using the options set in this object.
-    public func start() -> Promise<MKMapSnapshot> {
-        return Promise { start(completionHandler: $0.resolve) }
-    }
-#endif
-}
+import MapKit
+#if !PMKCocoaPods
+import PromiseKit
+#endif
+
+/**
+ To import the `MKMapSnapshotter` category:
+
+    use_frameworks!
+    pod "PromiseKit/MapKit"
+
+ And then in your sources:
+
+    import PromiseKit
+*/
+extension MKMapSnapshotter {
+#if swift(>=4.2)
+    /// Starts generating the snapshot using the options set in this object.
+    /// - Note: cancelling this promise will cancel the underlying task
+    /// - SeeAlso: [Cancellation](http://promisekit.org/docs/)
+    public func start() -> Promise<Snapshot> {
+        return Promise<Snapshot>(cancellableTask: MKMapSnapshotterTask(self)) { start(completionHandler: $0.resolve) }
+    }
+#else
+    /// Starts generating the snapshot using the options set in this object.
+    /// - Note: cancelling this promise will cancel the underlying task
+    /// - SeeAlso: [Cancellation](http://promisekit.org/docs/)
+    public func start() -> Promise<MKMapSnapshot> {
+        return Promise<MKMapSnapshot>(cancellableTask: MKMapSnapshotterTask(self)) { start(completionHandler: $0.resolve) }
+    }
+#endif
+}
+
+private class MKMapSnapshotterTask: CancellableTask {
+    let snapshotter: MKMapSnapshotter
+    var cancelAttempted = false
+
+    init(_ snapshotter: MKMapSnapshotter) {
+        self.snapshotter = snapshotter
+    }
+
+    func cancel() {
+        snapshotter.cancel()
+        cancelAttempted = true
+    }
+
+    var isCancelled: Bool {
+        return cancelAttempted && !snapshotter.isLoading
+    }
+}

Tests/TestMapKit.swift

@@ -61,3 +61,70 @@ class Test_MKSnapshotter_Swift: XCTestCase {
         waitForExpectations(timeout: 1, handler: nil)
     }
 }
+
+//////////////////////////////////////////////////////////// Cancellation
+
+extension Test_MKDirections_Swift {
+    func test_cancel_directions_response() {
+        let ex = expectation(description: "")
+
+        class MockDirections: MKDirections {
+            override func calculate(completionHandler: @escaping MKDirectionsHandler) {
+                completionHandler(MKDirectionsResponse(), nil)
+            }
+        }
+
+        let rq = MKDirectionsRequest()
+        let directions = MockDirections(request: rq)
+
+        cancellable(directions.calculate()).done { _ in
+            XCTFail()
+        }.catch(policy: .allErrors) {
+            $0.isCancelled ? ex.fulfill() : XCTFail()
+        }.cancel()
+
+        waitForExpectations(timeout: 1, handler: nil)
+    }
+
+
+    func test_cancel_ETA_response() {
+        let ex = expectation(description: "")
+
+        class MockDirections: MKDirections {
+            override func calculateETA(completionHandler: @escaping MKETAHandler) {
+                completionHandler(MKETAResponse(), nil)
+            }
+        }
+
+        let rq = MKDirectionsRequest()
+        cancellable(MockDirections(request: rq).calculateETA()).done { _ in
+            XCTFail()
+        }.catch(policy: .allErrors) {
+            $0.isCancelled ? ex.fulfill() : XCTFail()
+        }.cancel()
+
+        waitForExpectations(timeout: 1, handler: nil)
+    }
+
+}
+
+extension Test_MKSnapshotter_Swift {
+    func test_cancel() {
+        let ex = expectation(description: "")
+
+        class MockSnapshotter: MKMapSnapshotter {
+            override func start(completionHandler: @escaping MKMapSnapshotCompletionHandler) {
+                completionHandler(MKMapSnapshot(), nil)
+            }
+        }
+
+        let snapshotter = MockSnapshotter()
+        cancellable(snapshotter.start()).done { _ in
+            XCTFail()
+        }.catch(policy: .allErrors) {
+            $0.isCancelled ? ex.fulfill() : XCTFail()
+        }.cancel()
+
+        waitForExpectations(timeout: 1, handler: nil)
+    }
+}