Remove `ParasiticTask`, now `host` is a built-in parameter for all tasks.

Schedule.xcodeproj/project.pbxproj

@@ -32,7 +32,6 @@
 		OBJ_48 /* Interval.swift in Sources */ = {isa = PBXBuildFile; fileRef = OBJ_12 /* Interval.swift */; };
 		OBJ_49 /* Lock.swift in Sources */ = {isa = PBXBuildFile; fileRef = OBJ_13 /* Lock.swift */; };
 		OBJ_50 /* Monthday.swift in Sources */ = {isa = PBXBuildFile; fileRef = OBJ_14 /* Monthday.swift */; };
-		OBJ_51 /* ParasiticTask.swift in Sources */ = {isa = PBXBuildFile; fileRef = OBJ_15 /* ParasiticTask.swift */; };
 		OBJ_52 /* Period.swift in Sources */ = {isa = PBXBuildFile; fileRef = OBJ_16 /* Period.swift */; };
 		OBJ_53 /* Schedule.swift in Sources */ = {isa = PBXBuildFile; fileRef = OBJ_17 /* Schedule.swift */; };
 		OBJ_54 /* Task.swift in Sources */ = {isa = PBXBuildFile; fileRef = OBJ_18 /* Task.swift */; };
@@ -82,7 +81,6 @@
 		OBJ_12 /* Interval.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = Interval.swift; sourceTree = "<group>"; };
 		OBJ_13 /* Lock.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = Lock.swift; sourceTree = "<group>"; };
 		OBJ_14 /* Monthday.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = Monthday.swift; sourceTree = "<group>"; };
-		OBJ_15 /* ParasiticTask.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = ParasiticTask.swift; sourceTree = "<group>"; };
 		OBJ_16 /* Period.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = Period.swift; sourceTree = "<group>"; };
 		OBJ_17 /* Schedule.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = Schedule.swift; sourceTree = "<group>"; };
 		OBJ_18 /* Task.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = Task.swift; sourceTree = "<group>"; };
@@ -222,7 +220,6 @@
 		OBJ_8 /* Schedule */ = {
 			isa = PBXGroup;
 			children = (
-				OBJ_15 /* ParasiticTask.swift */,
 				66D9F43221563D7700D9F441 /* RunLoopTask.swift */,
 				OBJ_17 /* Schedule.swift */,
 				OBJ_18 /* Task.swift */,
@@ -352,7 +349,6 @@
 				OBJ_48 /* Interval.swift in Sources */,
 				OBJ_49 /* Lock.swift in Sources */,
 				OBJ_50 /* Monthday.swift in Sources */,
-				OBJ_51 /* ParasiticTask.swift in Sources */,
 				OBJ_52 /* Period.swift in Sources */,
 				OBJ_53 /* Schedule.swift in Sources */,
 				OBJ_54 /* Task.swift in Sources */,

Sources/Schedule/DeinitObserver.swift

@@ -9,24 +9,34 @@ import Foundation
 
 #if os(macOS) || os(iOS) || os(tvOS) || os(watchOS)
 
-class DeinitObserver<T: AnyObject> {
+private var deinitObserverKey: Void = ()
 
-    private weak var observed: T?
+class DeinitObserver {
 
-    private var block: () -> Void
+    private(set) weak var observable: AnyObject?
+
+    private var block: (() -> Void)?
 
     private init(_ block: @escaping () -> Void) {
         self.block = block
     }
 
-    static func observe(_ observed: T, whenDeinit: @escaping () -> Void) {
+    @discardableResult
-        let observer = DeinitObserver(whenDeinit)
+    static func observe(_ observable: AnyObject, whenDeinit block: @escaping () -> Void) -> DeinitObserver {
-        var key: Void = ()
+        let observer = DeinitObserver(block)
-        objc_setAssociatedObject(observed, &key, observer, .OBJC_ASSOCIATION_RETAIN)
+        objc_setAssociatedObject(observable, &deinitObserverKey, observer, .OBJC_ASSOCIATION_RETAIN_NONATOMIC)
+        return observer
+    }
+
+    func clear() {
+        block = nil
+        if let o = observable {
+            objc_setAssociatedObject(o, &deinitObserverKey, nil, .OBJC_ASSOCIATION_ASSIGN)
+        }
     }
 
     deinit {
-        block()
+        block?()
     }
 }
 

Sources/Schedule/ParasiticTask.swift

@@ -1,81 +0,0 @@
-//
-//  ParasiticTask.swift
-//  Schedule
-//
-//  Created by Quentin Jin on 2018/7/17.
-//
-
-import Foundation
-
-extension Schedule {
-
-    /// Schedules a task with this schedule.
-    ///
-    /// This method will receive a `host` object as a parameter,
-    /// the returned task will not retain this object, instead,
-    /// it will observe this object, when this object is dealloced,
-    /// the task will not be scheduled any more, something like parasitism.
-    ///
-    /// This feature is very useful when you want a scheduled task live and die
-    /// with a controller.
-    ///
-    /// - Parameters:
-    ///   - queue: The queue to which the task will be dispatched.
-    ///   - tag: The tag to be associated to the task.
-    ///   - host: The object to be hosted on.
-    ///   - onElapse: The action to do when time is out.
-    /// - Returns: The task just created.
-    @discardableResult
-    public func `do`(queue: DispatchQueue,
-                     tag: String? = nil,
-                     host: AnyObject,
-                     onElapse: @escaping (Task) -> Void) -> Task {
-        return ParasiticTask(schedule: self, queue: queue, tag: tag, host: host, onElapse: onElapse)
-    }
-
-    /// Schedules a task with this schedule.
-    ///
-    /// This method will receive a `host` object as a parameter,
-    /// the returned task will not retain this object, instead,
-    /// it will observe this object, when this object is dealloced,
-    /// the task will not scheduled any more, something like parasitism.
-    ///
-    /// This feature is very useful when you want a scheduled task live and die
-    /// with a controller.
-    ///
-    /// - Parameters:
-    ///   - queue: The queue to which the task will be dispatched.
-    ///   - tag: The tag to be associated to the task.
-    ///   - host: The object to be hosted on.
-    ///   - onElapse: The action to do when time is out.
-    /// - Returns: The task just created.
-    @discardableResult
-    public func `do`(queue: DispatchQueue,
-                     tag: String? = nil,
-                     host: AnyObject,
-                     onElapse: @escaping () -> Void) -> Task {
-        return self.do(queue: queue, tag: tag, host: host, onElapse: { (_) in onElapse() })
-    }
-}
-
-private final class ParasiticTask: Task {
-
-    weak var parasitifer: AnyObject?
-
-    init(schedule: Schedule, queue: DispatchQueue?, tag: String?, host: AnyObject, onElapse: @escaping (Task) -> Void) {
-        super.init(schedule: schedule, queue: queue, tag: tag) { (task) in
-            guard (task as? ParasiticTask)?.parasitifer != nil else {
-                task.cancel()
-                return
-            }
-            onElapse(task)
-        }
-        self.parasitifer = host
-
-        #if os(macOS) || os(iOS) || os(tvOS) || os(watchOS)
-        DeinitObserver.observe(host) { [weak self] in
-            self?.cancel()
-        }
-        #endif
-    }
-}

Sources/Schedule/RunLoopTask.swift

@@ -11,48 +11,30 @@ extension Schedule {
 
     /// Schedules a task with this schedule.
     ///
-    /// This method will receive a `host` object as a parameter,
-    /// the returned task will not retain this object, instead,
-    /// it will observe this object, when this object is dealloced,
-    /// the task will not be scheduled any more, something like parasitism.
-    ///
-    /// This feature is very useful when you want a scheduled task live and die
-    /// with a controller.
-    ///
     /// - Parameters:
-    ///   - queue: The queue to which the task will be dispatched.
+    ///   - mode: The mode in which to add the schedule.
-    ///   - tag: The tag to be associated to the task.
     ///   - host: The object to be hosted on.
     ///   - onElapse: The action to do when time is out.
     /// - Returns: The task just created.
     @discardableResult
     public func `do`(mode: RunLoop.Mode = .default,
-                     tag: String? = nil,
+                     host: AnyObject? = nil,
                      onElapse: @escaping (Task) -> Void) -> Task {
-        return RunLoopTask(schedule: self, mode: mode, tag: tag, onElapse: onElapse)
+        return RunLoopTask(schedule: self, mode: mode, host: host, onElapse: onElapse)
     }
 
     /// Schedules a task with this schedule.
     ///
-    /// This method will receive a `host` object as a parameter,
-    /// the returned task will not retain this object, instead,
-    /// it will observe this object, when this object is dealloced,
-    /// the task will not scheduled any more, something like parasitism.
-    ///
-    /// This feature is very useful when you want a scheduled task live and die
-    /// with a controller.
-    ///
     /// - Parameters:
-    ///   - queue: The queue to which the task will be dispatched.
+    ///   - mode: The mode in which to add the schedule.
-    ///   - tag: The tag to be associated to the task.
     ///   - host: The object to be hosted on.
     ///   - onElapse: The action to do when time is out.
     /// - Returns: The task just created.
     @discardableResult
     public func `do`(mode: RunLoop.Mode = .default,
-                     tag: String? = nil,
+                     host: AnyObject? = nil,
                      onElapse: @escaping () -> Void) -> Task {
-        return self.do(mode: mode, tag: tag) { (_) in
+        return self.do(mode: mode, host: host) { (_) in
             onElapse()
         }
     }
@@ -62,7 +44,7 @@ private final class RunLoopTask: Task {
 
     var timer: Timer!
 
-    init(schedule: Schedule, mode: RunLoop.Mode, tag: String?, onElapse: @escaping (Task) -> Void) {
+    init(schedule: Schedule, mode: RunLoop.Mode, host: AnyObject?, onElapse: @escaping (Task) -> Void) {
 
         var this: Task?
 
@@ -74,7 +56,7 @@ private final class RunLoopTask: Task {
 
         RunLoop.current.add(timer, forMode: mode)
 
-        super.init(schedule: schedule, queue: nil, tag: tag) { (task) in
+        super.init(schedule: schedule, queue: nil, host: host) { (task) in
             guard let task = task as? RunLoopTask else { return }
             task.timer.fireDate = Date()
         }

Sources/Schedule/Schedule.swift

@@ -26,28 +26,30 @@ public struct Schedule {
     ///
     /// - Parameters:
     ///   - queue: The queue to which the task will be dispatched.
-    ///   - tag: The tag to be associated to the task.
+    ///   - host: The object to be hosted on. When this object is dealloced,
+    ///           the task will not scheduled any more.
     ///   - onElapse: The action to do when time is out.
     /// - Returns: The task just created.
     @discardableResult
     public func `do`(queue: DispatchQueue,
-                     tag: String? = nil,
+                     host: AnyObject? = nil,
                      onElapse: @escaping (Task) -> Void) -> Task {
-        return Task(schedule: self, queue: queue, tag: tag, onElapse: onElapse)
+        return Task(schedule: self, queue: queue, host: host, onElapse: onElapse)
     }
 
     /// Schedules a task with this schedule.
     ///
     /// - Parameters:
     ///   - queue: The queue to which the task will be dispatched.
-    ///   - tag: The tag to be associated to the task.
+    ///   - host: The object to be hosted on. When this object is dealloced,
+    ///           the task will not scheduled any more.
     ///   - onElapse: The action to do when time is out.
     /// - Returns: The task just created.
     @discardableResult
     public func `do`(queue: DispatchQueue,
-                     tag: String? = nil,
+                     host: AnyObject? = nil,
                      onElapse: @escaping () -> Void) -> Task {
-        return self.do(queue: queue, tag: tag, onElapse: { (_) in onElapse() })
+        return self.do(queue: queue, host: host, onElapse: { (_) in onElapse() })
     }
 }
 

Sources/Schedule/Task.swift

@@ -34,6 +34,10 @@ public class Task {
     private lazy var _tags: Set<String> = []
     private lazy var _countOfExecutions: Int = 0
 
+    #if os(Linux)
+    private weak var _host: AnyObject? = TaskHub.shared
+    #endif
+
     private lazy var _lifetime: Interval = Int.max.second
     private lazy var _lifetimeTimer: DispatchSourceTimer = {
         let timer = DispatchSource.makeTimerSource()
@@ -47,8 +51,8 @@ public class Task {
     }()
 
     init(schedule: Schedule,
-         queue: DispatchQueue? = nil,
+         queue: DispatchQueue?,
-         tag: String? = nil,
+         host: AnyObject?,
          onElapse: @escaping (Task) -> Void) {
 
         _iterator = schedule.makeIterator()
@@ -57,6 +61,14 @@ public class Task {
         _actions.append(onElapse)
 
         _timer.setEventHandler { [weak self] in
+
+            #if os(Linux)
+            guard self?._host != nil else {
+                self?.cancel()
+                return
+            }
+            #endif
+
             self?.elapse()
         }
 
@@ -65,7 +77,18 @@ public class Task {
         _timer.schedule(after: interval)
         _timeline.estimatedNextExecution = Date().adding(interval)
 
-        TaskHub.shared.add(self, withTag: tag)
+        #if os(Linux)
+        _host = host
+        #else
+        if let host = host {
+            DeinitObserver.observe(host) { [weak self] in
+                self?.cancel()
+            }
+        }
+        #endif
+
+        TaskHub.shared.add(self)
+
         _timer.resume()
     }
 
@@ -341,9 +364,6 @@ public class Task {
     public func removeTag(_ tag: String) {
         removeTags(tag)
     }
-}
-
-extension Task {
 
     /// Suspends all tasks that have the tag.
     public static func suspend(byTag tag: String) {