40 lines
1018 B
Swift
40 lines
1018 B
Swift
//
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// WeakDictionaryKeyReference.swift
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// WeakDictionary-iOS
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//
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// Created by Nicholas Cross on 2/1/19.
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// Copyright © 2019 Nicholas Cross. All rights reserved.
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//
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import Foundation
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public struct WeakDictionaryKey<Key: AnyObject & Hashable, Value: AnyObject>: Hashable {
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private weak var baseKey: Key?
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private let hash: Int
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private var retainedValue: Value?
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private let nilKeyHash = UUID().hashValue
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public init(key: Key, value: Value? = nil) {
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baseKey = key
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retainedValue = value
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hash = key.hashValue
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}
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public static func == (lhs: WeakDictionaryKey, rhs: WeakDictionaryKey) -> Bool {
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(lhs.baseKey != nil && rhs.baseKey != nil && lhs.baseKey == rhs.baseKey)
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|| lhs.hashValue == rhs.hashValue
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}
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public func hash(into hasher: inout Hasher) {
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if baseKey == nil {
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hasher.combine(nilKeyHash)
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} else {
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hasher.combine(baseKey)
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}
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}
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public var key: Key? {
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baseKey
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}
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}
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