0001    //
0002    //  MainScheduler.swift
0003    //  Rx
0004    //
0005    //  Created by Krunoslav Zaher on 2/8/15.
0006    //  Copyright © 2015 Krunoslav Zaher. All rights reserved.
0007    //
0008    
0009    import Foundation
0010    
0011    /**
0012    Abstracts work that needs to be performed on `MainThread`. In case `schedule` methods are called from main thread, it will perform action immediately without scheduling.
0013    
0014    This scheduler is usually used to perform UI work.
0015    
0016    Main scheduler is a specialization of `SerialDispatchQueueScheduler`.
0017    
0018    This scheduler is optimized for `observeOn` operator. To ensure observable sequence is subscribed on main thread using `subscribeOn`
0019    operator please use `ConcurrentMainScheduler` because it is more optimized for that purpose.
0020    */
0021    public final class MainScheduler
ConcurrentDispatchQueueScheduler.swift:96
        let dispatchInterval = MainScheduler.convertTimeIntervalToDispatchTime(dueTime)
ConcurrentDispatchQueueScheduler.swift:128
        let initial = MainScheduler.convertTimeIntervalToDispatchTime(startAfter)
ConcurrentDispatchQueueScheduler.swift:129
        let dispatchInterval = MainScheduler.convertTimeIntervalToDispatchInterval(period)
ConcurrentMainScheduler.swift:21
    private let _mainScheduler: MainScheduler
ConcurrentMainScheduler.swift:33
    private init(mainScheduler: MainScheduler) {
ConcurrentMainScheduler.swift:41
    public static let instance = ConcurrentMainScheduler(mainScheduler: MainScheduler.instance)
MainScheduler.swift:35
    public static let instance = MainScheduler()
SerialDispatchQueueScheduler.swift:133
        let dispatchInterval = MainScheduler.convertTimeIntervalToDispatchTime(dueTime)
SerialDispatchQueueScheduler.swift:165
        let initial = MainScheduler.convertTimeIntervalToDispatchTime(startAfter)
SerialDispatchQueueScheduler.swift:166
        let dispatchInterval = MainScheduler.convertTimeIntervalToDispatchInterval(period)
VirtualTimeScheduler.swift:118
        MainScheduler.ensureExecutingOnScheduler()
VirtualTimeScheduler.swift:147
        MainScheduler.ensureExecutingOnScheduler()
VirtualTimeScheduler.swift:189
        MainScheduler.ensureExecutingOnScheduler()
VirtualTimeScheduler.swift:221
        MainScheduler.ensureExecutingOnScheduler()
VirtualTimeScheduler.swift:235
        MainScheduler.ensureExecutingOnScheduler()
 : SerialDispatchQueueScheduler {
0022    
0023        private let _mainQueue
MainScheduler.swift:28
        _mainQueue = dispatch_get_main_queue()
MainScheduler.swift:29
        super.init(serialQueue: _mainQueue)
MainScheduler.swift:57
        dispatch_async(_mainQueue) {
: dispatch_queue_t
0024    
0025        var numberEnqueued
MainScheduler.swift:47
        let currentNumberEnqueued = AtomicIncrement(&numberEnqueued)
MainScheduler.swift:51
            AtomicDecrement(&numberEnqueued)
MainScheduler.swift:62
            AtomicDecrement(&self.numberEnqueued)
: AtomicInt = 0
0026    
0027        private init
MainScheduler.swift:35
    public static let instance = MainScheduler()
() {
0028            _mainQueue = dispatch_get_main_queue()
0029            super.init(serialQueue: _mainQueue)
0030        }
0031    
0032        /**
0033        Singleton instance of `MainScheduler`
0034        */
0035        public static let instance
ConcurrentMainScheduler.swift:41
    public static let instance = ConcurrentMainScheduler(mainScheduler: MainScheduler.instance)
 = MainScheduler()
0036    
0037        /**
0038        In case this method is called on a background thread it will throw an exception.
0039        */
0040        public class func ensureExecutingOnScheduler
VirtualTimeScheduler.swift:118
        MainScheduler.ensureExecutingOnScheduler()
VirtualTimeScheduler.swift:147
        MainScheduler.ensureExecutingOnScheduler()
VirtualTimeScheduler.swift:189
        MainScheduler.ensureExecutingOnScheduler()
VirtualTimeScheduler.swift:221
        MainScheduler.ensureExecutingOnScheduler()
VirtualTimeScheduler.swift:235
        MainScheduler.ensureExecutingOnScheduler()
() {
0041            if !NSThread.currentThread().isMainThread {
0042                rxFatalError("Executing on backgound thread. Please use `MainScheduler.instance.schedule` to schedule work on main thread.")
0043            }
0044        }
0045    
0046        override func scheduleInternal<StateType>(state: StateType, action: StateType -> Disposable) -> Disposable {
0047            let currentNumberEnqueued = AtomicIncrement(&numberEnqueued)
0048    
0049            if NSThread.currentThread().isMainThread && currentNumberEnqueued == 1 {
0050                let disposable = action(state)
0051                AtomicDecrement(&numberEnqueued)
0052                return disposable
0053            }
0054    
0055            let cancel = SingleAssignmentDisposable()
0056    
0057            dispatch_async(_mainQueue) {
0058                if !cancel.disposed {
0059                    action(state)
0060                }
0061    
0062                AtomicDecrement(&self.numberEnqueued)
0063            }
0064    
0065            return cancel
0066        }
0067    }
0068