Move `task.taskCenter` management to Task.swift

Sources/Schedule/Task.swift

@@ -27,7 +27,6 @@ open class Task {
     private var _timer: DispatchSourceTimer
 
     private lazy var _onElapseActions = Bag<Action>()
-    private lazy var _onDeinitActions = Bag<Action>()
 
     private lazy var _suspensions: UInt64 = 0
     private lazy var _timeline = Timeline()
@@ -45,11 +44,39 @@ open class Task {
         return timer
     }()
 
+    private weak var _taskCenter: TaskCenter?
+    
     /// The task center which this task currently in.
-    open internal(set) weak var taskCenter: TaskCenter?
+    open var taskCenter: TaskCenter? {
+        return _taskCenter
+    }
     
     /// The mutex used to guard task center operations.
-    let taskCenterMutex = NSRecursiveLock()
+    private let _taskCenterLock = NSRecursiveLock()
+    
+    /// Adds this task to the given task center.
+    ///
+    /// If this task is already in a task center, it will be removed from that center first.
+    func addToTaskCenter(_ center: TaskCenter) {
+        _taskCenterLock.lock()
+        defer { _taskCenterLock.unlock() }
+        
+        if _taskCenter === center { return }
+        
+        _taskCenter?.remove(self)
+        _taskCenter = center
+    }
+    
+    /// Removes this task from the given task center.
+    func removeFromTaskCenter(_ center: TaskCenter) {
+        _taskCenterLock.lock()
+        defer { _taskCenterLock.unlock() }
+        
+        if _taskCenter !== center { return }
+        
+        _taskCenter?.remove(self)
+        _taskCenter = nil
+    }
 
     /// Initializes a normal task with specified plan and dispatch queue.
     ///
@@ -81,16 +108,14 @@ open class Task {
     }
 
     deinit {
-        for action in _onDeinitActions {
-            action(self)
-        }
-
         while _suspensions > 0 {
             _timer.resume()
             _suspensions -= 1
         }
 
         cancel()
+        
+        taskCenter?.remove(self)
     }
 
     private func scheduleNext() {
@@ -196,13 +221,6 @@ open class Task {
         TaskCenter.default.remove(self)
     }
 
-    @discardableResult
-    open func onDeinit(_ body: @escaping Action) -> ActionKey {
-        return _mutex.withLock {
-            return _onDeinitActions.append(body).asActionKey()
-        }
-    }
-
     // MARK: - Lifecycle
 
     /// The snapshot timeline of this task.
@@ -337,7 +355,6 @@ extension Task: CustomStringConvertible {
         return "Task: { " +
         "\"isCancelled\": \(_timer.isCancelled), " +
         "\"countOfElapseActions\": \(_onElapseActions.count), " +
-        "\"countOfDeinitActions\": \(_onDeinitActions.count), " +
         "\"countOfExecutions\": \(_countOfExecutions), " +
         "\"lifeTime\": \(_lifetime), " +
         "\"timeline\": \(_timeline)" +

Sources/Schedule/TaskCenter.swift

@@ -8,7 +8,6 @@ extension TaskCenter {
 
         weak var task: Task?
 
-        // Used to find slot
         let hash: Int
 
         init(_ task: Task) {
@@ -20,68 +19,52 @@ extension TaskCenter {
             hasher.combine(hash)
         }
 
-        // Used to find task
         static func == (lhs: TaskBox, rhs: TaskBox) -> Bool {
             return lhs.task == rhs.task
         }
     }
 }
 
-/// A task mamanger that enables batch tasks operation.
+/// A task center that enables batch operation.
 open class TaskCenter {
 
-    private let mutex = NSLock()
+    private let lock = NSLock()
 
-    private var taskMap: [String: Set<TaskBox>] = [:]
+    private var tasksOfTag: [String: Set<TaskBox>] = [:]
-    private var tagMap: [TaskBox: Set<String>] = [:]
+    private var tagsOfTask: [TaskBox: Set<String>] = [:]
 
+    /// Default task center.
     open class var `default`: TaskCenter {
         return _default
     }
 
-    /// Adds a task to this center.
+    /// Adds the given task to this center.
     ///
     /// Center won't retain the task.
     open func add(_ task: Task) {
-        task.taskCenterMutex.lock()
+        task.addToTaskCenter(self)
 
-        if let center = task.taskCenter {
+        lock.withLockVoid {
-            if center === self { return }
-            center.remove(task)
-        }
-        task.taskCenter = self
-
-        task.taskCenterMutex.unlock()
-
-        mutex.withLockVoid {
             let box = TaskBox(task)
-            tagMap[box] = []
+            tagsOfTask[box] = []
-        }
-
-        task.onDeinit { [weak self] (t) in
-            guard let self = self else { return }
-            self.remove(t)
         }
     }
 
-    /// Removes a task from this center.
+    /// Removes the given task from this center.
     open func remove(_ task: Task) {
-        task.taskCenterMutex.lock()
+        task.removeFromTaskCenter(self)
 
-        guard task.taskCenter === self else {
+        lock.withLockVoid {
-            return
-        }
-        task.taskCenter = nil
-
-        task.taskCenterMutex.unlock()
-
-        mutex.withLockVoid {
             let box = TaskBox(task)
-            if let tags = self.tagMap[box] {
+            if let tags = self.tagsOfTask[box] {
                 for tag in tags {
-                    self.taskMap[tag]?.remove(box)
+                    self.tasksOfTag[tag]?.remove(box)
+                    
+                    if self.tasksOfTag[tag]?.count == 0 {
+                        self.tasksOfTag[tag] = nil
+                    }
                 }
-                self.tagMap[box] = nil
+                self.tagsOfTask[box] = nil
             }
         }
     }
@@ -99,17 +82,17 @@ open class TaskCenter {
     open func addTags(_ tags: [String], to task: Task) {
         guard task.taskCenter === self else { return }
 
-        mutex.withLockVoid {
+        lock.withLockVoid {
             let box = TaskBox(task)
-            if tagMap[box] == nil {
+            if tagsOfTask[box] == nil {
-                tagMap[box] = []
+                tagsOfTask[box] = []
             }
             for tag in tags {
-                tagMap[box]?.insert(tag)
+                tagsOfTask[box]?.insert(tag)
-                if taskMap[tag] == nil {
+                if tasksOfTag[tag] == nil {
-                    taskMap[tag] = []
+                    tasksOfTag[tag] = []
                 }
-                taskMap[tag]?.insert(box)
+                tasksOfTag[tag]?.insert(box)
             }
         }
     }
@@ -127,11 +110,11 @@ open class TaskCenter {
     open func removeTags(_ tags: [String], from task: Task) {
         guard task.taskCenter === self else { return }
 
-        mutex.withLockVoid {
+        lock.withLockVoid {
             let box = TaskBox(task)
             for tag in tags {
-                tagMap[box]?.remove(tag)
+                tagsOfTask[box]?.remove(tag)
-                taskMap[tag]?.remove(box)
+                tasksOfTag[tag]?.remove(box)
             }
         }
     }
@@ -142,37 +125,37 @@ open class TaskCenter {
     open func tagsForTask(_ task: Task) -> [String] {
         guard task.taskCenter === self else { return [] }
 
-        return mutex.withLock {
+        return lock.withLock {
-            Array(tagMap[TaskBox(task)] ?? [])
+            Array(tagsOfTask[TaskBox(task)] ?? [])
         }
     }
 
     /// Returns all tasks that have the tag.
     open func tasksForTag(_ tag: String) -> [Task] {
-        return mutex.withLock {
+        return lock.withLock {
-            taskMap[tag]?.compactMap { $0.task } ?? []
+            tasksOfTag[tag]?.compactMap { $0.task } ?? []
         }
     }
 
     /// Returns all tasks in this center.
     open var allTasks: [Task] {
-        return mutex.withLock {
+        return lock.withLock {
-            tagMap.compactMap { $0.key.task }
+            tagsOfTask.compactMap { $0.key.task }
         }
     }
 
     /// Returns all existing tags in this center.
     open var allTags: [String] {
-        return mutex.withLock {
+        return lock.withLock {
-            taskMap.map { $0.key }
+            tasksOfTag.map { $0.key }
         }
     }
 
-    /// Removes all tasks in this center.
+    /// Removes all tasks from this center.
-    open func clear() {
+    open func removeAll() {
-        mutex.withLockVoid {
+        lock.withLockVoid {
-            tagMap = [:]
+            tagsOfTask = [:]
-            taskMap = [:]
+            tasksOfTag = [:]
         }
     }
 

Tests/ScheduleTests/TaskCenterTests.swift

@@ -15,7 +15,7 @@ final class TaskCenterTests: XCTestCase {
     func testDefault() {
         let task = makeTask()
         XCTAssertTrue(center.allTasks.contains(task))
-        center.clear()
+        center.removeAll()
     }
 
     func testAdd() {
@@ -31,7 +31,7 @@ final class TaskCenterTests: XCTestCase {
         c.add(task)
         XCTAssertEqual(c.allTasks.count, 1)
 
-        center.clear()
+        center.removeAll()
     }
 
     func testRemove() {
@@ -53,7 +53,7 @@ final class TaskCenterTests: XCTestCase {
         XCTAssertFalse(center.tasksForTag(tag).contains(task))
         XCTAssertFalse(center.tagsForTask(task).contains(tag))
 
-        center.clear()
+        center.removeAll()
     }
 
     func testAll() {
@@ -65,7 +65,7 @@ final class TaskCenterTests: XCTestCase {
         XCTAssertEqual(center.allTags, [tag])
         XCTAssertEqual(center.allTasks, [task])
 
-        center.clear()
+        center.removeAll()
     }
 
     func testOperation() {
@@ -84,7 +84,7 @@ final class TaskCenterTests: XCTestCase {
         center.cancelByTag(tag)
         XCTAssertTrue(task.isCancelled)
 
-        center.clear()
+        center.removeAll()
     }
 
     func testWeak() {