0001    // Debounce.swift
0002    //
0003    // Copyright (c) 2015 Jens Ravens (http://jensravens.de)
0004    //
0005    // Permission is hereby granted, free of charge, to any person obtaining a copy
0006    // of this software and associated documentation files (the "Software"), to deal
0007    // in the Software without restriction, including without limitation the rights
0008    // to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
0009    // copies of the Software, and to permit persons to whom the Software is
0010    // furnished to do so, subject to the following conditions:
0011    //
0012    // The above copyright notice and this permission notice shall be included in
0013    // all copies or substantial portions of the Software.
0014    //
0015    // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
0016    // IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
0017    // FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
0018    // AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
0019    // LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
0020    // OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
0021    // THE SOFTWARE.
0022    
0023    import Foundation
0024    
0025    private var SignalUpdateCalledHandle
Debounce.swift:31
            if let handle = objc_getAssociatedObject(self, &SignalUpdateCalledHandle) as? NSDate {
Debounce.swift:38
            objc_setAssociatedObject(self, &SignalUpdateCalledHandle, newValue, .OBJC_ASSOCIATION_RETAIN_NONATOMIC)
: UInt8 = 0
0026    public extension Signal {
0027        #if os(Linux)
0028        #else
0029        internal var lastCalled
Debounce.swift:54
                    let timeSinceLastCall = signal.lastCalled?.timeIntervalSinceNow
Debounce.swift:57
                        signal.lastCalled = NSDate()
Debounce.swift:61
                        if currentTime.compare(signal.lastCalled!) == .OrderedDescending {
: NSDate? {
0030            get {
0031                if let handle = objc_getAssociatedObject(self, &SignalUpdateCalledHandle) as? NSDate {
0032                    return handle
0033                } else {
0034                    return nil
0035                }
0036            }
0037            set {
0038                objc_setAssociatedObject(self, &SignalUpdateCalledHandle, newValue, .OBJC_ASSOCIATION_RETAIN_NONATOMIC)
0039            }
0040        }
0041        
0042        /**
0043            Creates a new signal that is only firing once per specified time interval. The last 
0044            call to update will always be delivered (although it might be delayed up to the
0045            specified amount of seconds).
0046        */
0047        public func debounce(seconds: NSTimeInterval) -> Signal<T> {
0048            let signal = Signal<T>()
0049            
0050            subscribe { result in
0051                let currentTime = NSDate()
0052                func updateIfNeeded(signal: Signal<T>) -> Result<T> -> Void {
0053                    return { result in
0054                        let timeSinceLastCall = signal.lastCalled?.timeIntervalSinceNow
0055                        if timeSinceLastCall == nil || timeSinceLastCall <= -seconds {
0056                            // no update before or update outside of debounce window
0057                            signal.lastCalled = NSDate()
0058                            signal.update(result)
0059                        } else {
0060                            // skip result if there was a newer result
0061                            if currentTime.compare(signal.lastCalled!) == .OrderedDescending {
0062                                let s = Signal<T>()
0063                                s.delay(seconds - timeSinceLastCall!).subscribe(updateIfNeeded(signal))
0064                                s.update(result)
0065                            }
0066                        }
0067                    }
0068                }
0069                updateIfNeeded(signal)(result)
0070            }
0071            
0072            return signal
0073        }
0074        #endif
0075    }