51 lines
1.9 KiB
Swift
51 lines
1.9 KiB
Swift
//
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// Copyright 2025 New Vector Ltd.
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//
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// SPDX-License-Identifier: AGPL-3.0-only OR LicenseRef-Element-Commercial
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// Please see LICENSE files in the repository root for full details.
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//
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import Foundation
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import Mutex
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extension Observable {
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/// Creates an async stream for the specified property on this object. We probably won't need this once SE-0475 is available:
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/// https://github.com/swiftlang/swift-evolution/blob/main/proposals/0475-observed.md
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///
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/// - Parameter property: The key path to the property you would like to observe.
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func observe<Value>(_ property: KeyPath<Self, Value>) -> AsyncStream<Value> {
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if #available(iOS 26, *) {
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let observations = Observations { self[keyPath: property] }
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return AsyncStream { continuation in
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let task = Task {
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for await value in observations {
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continuation.yield(value)
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}
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}
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continuation.onTermination = { _ in task.cancel() }
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}
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} else {
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return AsyncStream { continuation in
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let isActive = Mutex(true)
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@Sendable func observe() {
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let value = withObservationTracking {
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self[keyPath: property]
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} onChange: {
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// Handle the update on the next run loop as this is willSet not didSet.
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DispatchQueue.main.async {
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guard isActive.withLock({ $0 }) else { return }
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observe()
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}
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}
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continuation.yield(value)
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}
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continuation.onTermination = { _ in isActive.withLock { $0 = false } }
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observe()
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}
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}
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}
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}
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