Add cancel single task

Author: elvirion

CHANGELOG.md

@@ -1,5 +1,6 @@
 ## Added
 - ChunkSize argument to TUSClient initializer.
+- Add cancel single task.
 
 # 3.0.0
 - Rewrite of TUSKit

Sources/TUSKit/Scheduler.swift

@@ -32,7 +32,11 @@ final class Scheduler {
     private var runningTasks = [ScheduledTask]()
     weak var delegate: SchedulerDelegate?
 
-    var allTasks: [ScheduledTask] { runningTasks + pendingTasks }
+    var allTasks: [ScheduledTask] {
+        queue.sync {
+            runningTasks + pendingTasks
+        }
+    }
 
     // Tasks are processed in background
     let queue = DispatchQueue(label: "com.TUSKit.Scheduler")
@@ -61,6 +65,28 @@ final class Scheduler {
             self.runningTasks = []
         }
     }
+    
+    func cancelTasks(_ tasksToCancel: [ScheduledTask]) {
+        queue.async {
+            tasksToCancel.forEach { taskToCancel in
+                if let pendingTaskIndex = self.pendingTasks.firstIndex(where: { pendingTask in
+                    pendingTask === taskToCancel
+                }) {
+                    let pendingTask = self.pendingTasks[pendingTaskIndex]
+                    pendingTask.cancel()
+                    self.pendingTasks.remove(at: pendingTaskIndex)
+                }
+                
+                if let runningTaskIndex = self.runningTasks.firstIndex(where: { runningTask in
+                    runningTask === taskToCancel
+                }) {
+                    let runningTask = self.runningTasks[runningTaskIndex]
+                    runningTask.cancel()
+                    self.runningTasks.remove(at: runningTaskIndex)
+                }
+            }
+        }
+    }
 
     private func checkProcessNextTask() {
         queue.async { [weak self] in

Sources/TUSKit/TUSClient.swift

@@ -121,6 +121,11 @@ public final class TUSClient {
         scheduler.cancelAll()
     }
 
+    public func cancel(id: UUID) throws {
+        let tasksToCancel = scheduler.allTasks.filter { ($0 as? IdentifiableTask)?.id == id }
+        scheduler.cancelTasks(tasksToCancel)
+    }
+    
     /// This will cancel all running uploads and clear the local cache.
     /// Expect errors passed to the delegate for canceled tasks.
     /// - Warning: This method is destructive and will remove any stored cache.

Sources/TUSKit/Tasks/CreationTask.swift

@@ -9,10 +9,16 @@ import Foundation
 
 /// `CreationTask` Prepares the server for a file upload.
 /// The server will return a path to upload to.
-final class CreationTask: ScheduledTask {
+final class CreationTask: IdentifiableTask {
+    
+    // MARK: - IdentifiableTask
+    
+    var id: UUID {
+        metaData.id
+    }
 
     weak var progressDelegate: ProgressDelegate?
-    var metaData: UploadMetadata
+    let metaData: UploadMetadata
 
     private let api: TUSAPI
     private let files: Files

Sources/TUSKit/Tasks/IdentifiableTask.swift

@@ -0,0 +1,12 @@
+//
+//  IdentifiableTask.swift
+//  
+//
+//  Created by Elvirion Antersijn on 26/02/2022.
+//
+
+import Foundation
+
+protocol IdentifiableTask: ScheduledTask {
+    var id: UUID { get }
+}

Sources/TUSKit/Tasks/StatusTask.swift

@@ -8,7 +8,13 @@
 import Foundation
 
 /// A `StatusTask` fetches the status of an upload. It fetches the offset from we can continue uploading, and then makes a possible uploadtask.
-final class StatusTask: ScheduledTask {
+final class StatusTask: IdentifiableTask {
+    
+    // MARK: - IdentifiableTask
+    
+    var id: UUID {
+        metaData.id
+    }
 
     weak var progressDelegate: ProgressDelegate?
     let api: TUSAPI
@@ -58,6 +64,12 @@ final class StatusTask: ScheduledTask {
                 if offset == metaData.size {
                     completed(.success([]))
                 } else {
+                    // If the task has been canceled
+                    // we don't continue to create subsequent UploadDataTasks
+                    if self.didCancel {
+                        return
+                    }
+                    
                     let nextRange = offset..<min((offset + chunkSize), metaData.size)
 
                     let task = try UploadDataTask(api: api, metaData: metaData, files: files, range: nextRange)

Sources/TUSKit/Tasks/UploadDataTask.swift

@@ -9,7 +9,13 @@ import Foundation
 
 /// The upload task will upload to data a destination.
 /// Will spawn more UploadDataTasks if an upload isn't complete.
-final class UploadDataTask: NSObject, ScheduledTask {
+final class UploadDataTask: NSObject, IdentifiableTask {
+    
+    // MARK: - IdentifiableTask
+    
+    var id: UUID {
+        metaData.id
+    }
 
     weak var progressDelegate: ProgressDelegate?
     let metaData: UploadMetadata
@@ -112,6 +118,12 @@ final class UploadDataTask: NSObject, ScheduledTask {
 
                     try files.encodeAndStore(metaData: metaData)
 
+                    // If the task has been canceled
+                    // we don't continue to create subsequent UploadDataTasks
+                    if self.isCanceled {
+                        return
+                    }
+                    
                     let nextRange: Range<Int>?
                     if let range = range {
                         let chunkSize = range.count

Tests/TUSKitTests/SchedulerTests.swift

@@ -0,0 +1,34 @@
+//
+//  SchedulerTests.swift
+//  
+//
+//  Created by Elvirion Antersijn on 17/03/2022.
+//
+
+import XCTest
+@testable import TUSKit
+
+private final class TestTask: ScheduledTask {
+    func run(completed: @escaping TaskCompletion) {}
+    func cancel() {}
+}
+
+final class SchedulerTests: XCTestCase {
+    
+    private let scheduler = Scheduler()
+
+    func testAddTask() {
+        scheduler.addTask(task: TestTask())
+        XCTAssertEqual(scheduler.allTasks.count, 1)
+    }
+    
+    func testCancelTask() {
+        let taskToCancel = TestTask()
+        scheduler.addTask(task: taskToCancel)
+        XCTAssertEqual(scheduler.allTasks.count, 1)
+        
+        scheduler.cancelTasks([taskToCancel])
+        XCTAssertEqual(scheduler.allTasks.count, 0)
+    }
+   
+}

Tests/TUSKitTests/TUSClient/TUSClientTests.swift

@@ -57,6 +57,16 @@ final class TUSClientTests: XCTestCase {
         XCTAssertEqual(1, tusDelegate.finishedUploads.count, "Expected the previous and new upload to finish")
     }
 
+    func testCancelForID() throws {
+        let taskIDtoCancel = try client.upload(data: data)
+        
+        try client.cancel(id: taskIDtoCancel)
+        
+        XCTAssert(tusDelegate.finishedUploads.isEmpty)
+        XCTAssert(tusDelegate.failedUploads.isEmpty)
+        XCTAssert(tusDelegate.fileErrors.isEmpty)
+    }
+    
     // MARK: - Progress
 
     func testProgress() throws {
@@ -111,4 +121,11 @@ final class TUSClientTests: XCTestCase {
         waitForExpectations(timeout: 6, handler: nil)
     }
 
+    private func waitForUploadsToStart(_ amount: Int = 1) {
+        let uploadStartedExpectation = expectation(description: "Waiting for upload to start")
+        uploadStartedExpectation.expectedFulfillmentCount = amount
+        tusDelegate.startUploadExpectation = uploadStartedExpectation
+        waitForExpectations(timeout: 6, handler: nil)
+    }
+    
 }