41 lines
1.0 KiB
Swift
41 lines
1.0 KiB
Swift
//
|
|
// WeakDictionaryKeyReference.swift
|
|
// WeakDictionary-iOS
|
|
//
|
|
// Created by Nicholas Cross on 2/1/19.
|
|
// Copyright © 2019 Nicholas Cross. All rights reserved.
|
|
//
|
|
|
|
import Foundation
|
|
|
|
public struct WeakDictionaryKey<Key: AnyObject & Hashable, Value: AnyObject> : Hashable {
|
|
|
|
private weak var baseKey: Key?
|
|
private let hash: Int
|
|
private var retainedValue: Value?
|
|
private let nilKeyHash = UUID().hashValue
|
|
|
|
public init(key: Key, value: Value? = nil) {
|
|
baseKey = key
|
|
retainedValue = value
|
|
hash = key.hashValue
|
|
}
|
|
|
|
public static func == (lhs: WeakDictionaryKey, rhs: WeakDictionaryKey) -> Bool {
|
|
return (lhs.baseKey != nil && rhs.baseKey != nil && lhs.baseKey == rhs.baseKey)
|
|
|| lhs.hashValue == rhs.hashValue
|
|
}
|
|
|
|
public func hash(into hasher: inout Hasher) {
|
|
if baseKey == nil {
|
|
hasher.combine(nilKeyHash)
|
|
} else {
|
|
hasher.combine(baseKey)
|
|
}
|
|
}
|
|
|
|
public var key: Key? {
|
|
return baseKey
|
|
}
|
|
}
|