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//===----------------------------------------------------------------------===//
//
// This source file is part of the Swift open source project
//
// Copyright (c) 2024 Apple Inc. and the Swift project authors
// Licensed under Apache License v2.0 with Runtime Library Exception
//
// See http://swift.org/LICENSE.txt for license information
// See http://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
//
//===----------------------------------------------------------------------===//
import struct OrderedCollections.OrderedDictionary
/// Replacement for `Set` elements that can't be `Hashable`, but can be `Identifiable`.
public struct IdentifiableSet<Element: Identifiable>: Collection {
public init() {
self.storage = [:]
}
public init(_ sequence: some Sequence<Element>) {
self.storage = .init(pickLastWhenDuplicateFound: sequence)
}
fileprivate typealias Storage = OrderedDictionary<Element.ID, Element>
public struct Index: Comparable {
public static func < (lhs: IdentifiableSet<Element>.Index, rhs: IdentifiableSet<Element>.Index) -> Bool {
lhs.storageIndex < rhs.storageIndex
}
fileprivate let storageIndex: Storage.Index
}
private var storage: Storage
public var startIndex: Index {
Index(storageIndex: self.storage.elements.startIndex)
}
public var endIndex: Index {
Index(storageIndex: self.storage.elements.endIndex)
}
public var values: some Sequence<Element> {
self.storage.values
}
public subscript(position: Index) -> Element {
self.storage.elements[position.storageIndex].value
}
public subscript(id: Element.ID) -> Element? {
get {
self.storage[id]
}
set {
self.storage[id] = newValue
}
}
public func index(after i: Index) -> Index {
Index(storageIndex: self.storage.elements.index(after: i.storageIndex))
}
public mutating func insert(_ element: Element) {
self.storage[element.id] = element
}
public func union(_ otherSequence: some Sequence<Element>) -> Self {
var result = self
for element in otherSequence {
result.storage[element.id] = element
}
return result
}
public mutating func formUnion(_ otherSequence: some Sequence<Element>) {
for element in otherSequence {
self.storage[element.id] = element
}
}
public func intersection(_ otherSequence: some Sequence<Element>) -> Self {
let keysToRemove = Set(self.storage.keys).subtracting(otherSequence.map(\.id))
var result = Self()
for key in keysToRemove {
result.storage.removeValue(forKey: key)
}
return result
}
public func subtracting(_ otherSequence: some Sequence<Element>) -> Self {
var result = self
for element in otherSequence {
result.storage.removeValue(forKey: element.id)
}
return result
}
public func contains(id: Element.ID) -> Bool {
self.storage.keys.contains(id)
}
}
extension OrderedDictionary where Value: Identifiable, Key == Value.ID {
fileprivate init(pickLastWhenDuplicateFound sequence: some Sequence<Value>) {
self.init(sequence.map { ($0.id, $0) }, uniquingKeysWith: { $1 })
}
}
extension IdentifiableSet: Equatable {
public static func == (_ lhs: Self, _ rhs: Self) -> Bool {
lhs.storage.keys == rhs.storage.keys
}
}
extension IdentifiableSet: Hashable {
public func hash(into hasher: inout Hasher) {
for key in self.storage.keys {
hasher.combine(key)
}
}
}
extension IdentifiableSet: ExpressibleByArrayLiteral {
public init(arrayLiteral elements: Element...) {
self.init(elements)
}
}
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