Improve the implementaion of task center

Sources/Schedule/Task.swift

@@ -18,23 +18,21 @@ open class Task {
 
     // MARK: - Private properties
     
-    private let _lock = NSRecursiveLock()
+    private let _lock = NSLock()
 
     private var _iterator: AnyIterator<Interval>
     private let _timer: DispatchSourceTimer
 
-    private lazy var _actions = Bag<Action>()
+    private var _actions = Bag<Action>()
 
-    private lazy var _suspensionCount: Int = 0
+    private var _suspensionCount = 0
-    private lazy var _executionCount: Int = 0
+    private var _executionCount = 0
 
-    private lazy var _executionDates: [Date]? = nil
+    private var _executionDates: [Date]?
-    private lazy var _estimatedNextExecutionDate: Date? = nil
+    private var _estimatedNextExecutionDate: Date?
 
-    private weak var _taskCenter: TaskCenter?
+    private var _taskCenter: TaskCenter?
-    private let _taskCenterLock = NSRecursiveLock()
+    private var _tags: Set<String> = []
-
-    private var associateKey = 1
 
     // MARK: - Public properties
 
@@ -99,31 +97,6 @@ open class Task {
         return _lock.withLock { _taskCenter }
     }
 
-    // MARK: - Task center
-
-    /// Adds this task to the given task center.
-    func addToTaskCenter(_ center: TaskCenter) {
-        _taskCenterLock.lock()
-        defer { _taskCenterLock.unlock() }
-
-        if _taskCenter === center { return }
-
-        let c = _taskCenter
-        _taskCenter = center
-
-        c?.remove(self)
-    }
-
-    /// Removes this task from the given task center.
-    func removeFromTaskCenter(_ center: TaskCenter) {
-        _taskCenterLock.lock()
-        defer { _taskCenterLock.unlock() }
-
-        if _taskCenter !== center { return }
-
-        _taskCenter = nil
-        center.remove(self)
-    }
 
     // MARK: - Init
 
@@ -164,7 +137,7 @@ open class Task {
             _suspensionCount -= 1
         }
 
-        _taskCenter?.remove(self)
+        self.removeFromTaskCenter()
     }
 
     private func elapse() {
@@ -208,11 +181,14 @@ open class Task {
 
     /// Reschedules this task with the new plan.
     public func reschedule(_ new: Plan) {
-        _lock.withLockVoid {
+        _lock.lock()
-            if _timer.isCancelled { return }
+        if _timer.isCancelled {
+            _lock.unlock()
+            return
+        }
         
         _iterator = new.makeIterator()
-        }
+        _lock.unlock()
         scheduleNextExecution()
     }
 
@@ -269,6 +245,29 @@ open class Task {
             _actions.removeAll()
         }
     }
+    
+    /// Adds this task to the given task center.
+    func addToTaskCenter(_ center: TaskCenter) {
+        _lock.lock(); defer { _lock.unlock() }
+        
+        if _taskCenter === center { return }
+        
+        let c = _taskCenter
+        _taskCenter = center
+        c?.removeSimply(self)
+        center.addSimply(self)
+    }
+    
+    /// Removes this task from the given task center.
+    public func removeFromTaskCenter() {
+        _lock.lock(); defer { _lock.unlock() }
+        
+        guard let center = self._taskCenter else {
+            return
+        }
+        _taskCenter = nil
+        center.removeSimply(self)
+    }
 }
 
 extension Task: Hashable {
@@ -280,6 +279,6 @@ extension Task: Hashable {
 
     /// Returns a boolean value indicating whether two tasks are equal.
     public static func == (lhs: Task, rhs: Task) -> Bool {
-        return lhs === rhs
+        return lhs.id == rhs.id
     }
 }

Sources/Schedule/TaskCenter.swift

@@ -1,7 +1,5 @@
 import Foundation
 
-private let _default = TaskCenter()
-
 extension TaskCenter {
 
     private class TaskBox: Hashable {
@@ -27,6 +25,8 @@ extension TaskCenter {
     }
 }
 
+private let _default = TaskCenter()
+
 /// A task center that enables batch operation.
 open class TaskCenter {
 
@@ -41,30 +41,33 @@ open class TaskCenter {
     }
 
     /// Adds the given task to this center.
+    ///
+    /// Please note: task center will not retain tasks.
     open func add(_ task: Task) {
         task.addToTaskCenter(self)
+    }
     
+    func addSimply(_ task: Task) {
         lock.withLockVoid {
             let box = TaskBox(task)
             self.tasks[box] = []
         }
     }
     
-    /// Removes the given task from this center.
+    func removeSimply(_ task: Task) {
-    open func remove(_ task: Task) {
-        task.removeFromTaskCenter(self)
-
         lock.withLockVoid {
             let box = TaskBox(task)
-            if let tags = self.tasks[box] {
+            guard let tags = self.tasks[box] else {
+                return
+            }
+            
+            self.tasks[box] = nil
             for tag in tags {
                 self.tags[tag]?.remove(box)
                 if self.tags[tag]?.count == 0 {
                     self.tags[tag] = nil
                 }
             }
-                self.tasks[box] = nil
-            }
         }
     }
 
@@ -79,12 +82,14 @@ open class TaskCenter {
     ///
     /// If the task is not in this center, do nothing.
     open func addTags(_ tags: [String], to task: Task) {
-        guard task.taskCenter === self else { return }
-
         lock.withLockVoid {
             let box = TaskBox(task)
+            guard self.tasks[box] != nil else {
+                return
+            }
+            
             for tag in tags {
-                tasks[box]?.insert(tag)
+                self.tasks[box]?.insert(tag)
                 if self.tags[tag] == nil {
                     self.tags[tag] = []
                 }
@@ -104,10 +109,12 @@ open class TaskCenter {
     ///
     /// If the task is not in this center, do nothing.
     open func removeTags(_ tags: [String], from task: Task) {
-        guard task.taskCenter === self else { return }
-
         lock.withLockVoid {
             let box = TaskBox(task)
+            guard self.tasks[box] != nil else {
+                return
+            }
+            
             for tag in tags {
                 self.tasks[box]?.remove(tag)
                 self.tags[tag]?.remove(box)
@@ -122,8 +129,6 @@ open class TaskCenter {
     ///
     /// If the task is not in this center, return an empty array.
     open func tags(forTask task: Task) -> [String] {
-        guard task.taskCenter === self else { return [] }
-
         return lock.withLock {
             Array(tasks[TaskBox(task)] ?? [])
         }
@@ -152,9 +157,8 @@ open class TaskCenter {
 
     /// Removes all tasks from this center.
     open func removeAll() {
-        lock.withLockVoid {
+        allTasks.forEach {
-            tasks = [:]
+            $0.removeFromTaskCenter()
-            tags = [:]
         }
     }
 

Tests/ScheduleTests/TaskCenterTests.swift

@@ -40,7 +40,7 @@ final class TaskCenterTests: XCTestCase {
         let tag = UUID().uuidString
         center.addTag(tag, to: task)
 
-        center.remove(task)
+        task.removeFromTaskCenter()
 
         XCTAssertFalse(center.allTasks.contains(task))
         XCTAssertFalse(center.allTags.contains(tag))

Tests/ScheduleTests/TaskTests.swift

@@ -53,10 +53,7 @@ final class TaskTests: XCTestCase {
         let task = Plan.never.do { }
         XCTAssertTrue(task.taskCenter === TaskCenter.default)
 
-        task.removeFromTaskCenter(TaskCenter())
+        task.removeFromTaskCenter()
-        XCTAssertNotNil(task.taskCenter)
-
-        task.removeFromTaskCenter(task.taskCenter!)
         XCTAssertNil(task.taskCenter)
 
         let center = TaskCenter()