63 lines
1.9 KiB
Swift
63 lines
1.9 KiB
Swift
//
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// Swiftfin is subject to the terms of the Mozilla Public
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// License, v2.0. If a copy of the MPL was not distributed with this
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// file, you can obtain one at https://mozilla.org/MPL/2.0/.
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//
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// Copyright (c) 2024 Jellyfin & Jellyfin Contributors
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//
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import Foundation
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import OrderedCollections
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// TODO: documentation
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// TODO: find a better way to handle backgroundStates on action/state transitions
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// so that conformers don't have to manually insert/remove them
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// TODO: better/official way for subclasses of conformers to perform actions during
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// parent class actions
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// TODO: official way for a cleaner `respond` method so it doesn't have all Task
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// construction and get bloated
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protocol Stateful: AnyObject {
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associatedtype Action: Equatable
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associatedtype BackgroundState: Hashable = Never
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associatedtype State: Hashable
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/// Background states that the conformer can be in.
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/// Usually used to indicate background events that shouldn't
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/// set the conformer to a primary state.
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var backgroundStates: OrderedSet<BackgroundState> { get set }
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var lastAction: Action? { get set }
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var state: State { get set }
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/// Respond to a sent action and return the new state
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@MainActor
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func respond(to action: Action) -> State
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/// Send an action to the `Stateful` object, which will
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/// `respond` to the action and set the new state.
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@MainActor
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func send(_ action: Action)
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}
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extension Stateful {
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@MainActor
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func send(_ action: Action) {
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state = respond(to: action)
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lastAction = action
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}
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}
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extension Stateful where BackgroundState == Never {
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var backgroundStates: OrderedSet<Never> {
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get {
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assertionFailure("Attempted to access `backgroundStates` when there are none")
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return []
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}
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set { assertionFailure("Attempted to set `backgroundStates` when there are none") }
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}
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}
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