70 lines
2.9 KiB
Swift
70 lines
2.9 KiB
Swift
//
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// Copyright (c) 2022 Touch Instinct
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//
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// Permission is hereby granted, free of charge, to any person obtaining a copy
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// of this software and associated documentation files (the Software), to deal
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// in the Software without restriction, including without limitation the rights
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// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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// copies of the Software, and to permit persons to whom the Software is
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// furnished to do so, subject to the following conditions:
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//
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// The above copyright notice and this permission notice shall be included in
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// all copies or substantial portions of the Software.
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//
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// THE SOFTWARE IS PROVIDED AS IS, WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
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// THE SOFTWARE.
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//
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import Foundation
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private final class MapAsyncOperation<Output, Failure: Error>: AsyncOperation<Output, Failure> {
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private var dependencyObservation: NSKeyValueObservation?
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public init<DependencyOutput, DependencyFailure: Error>(dependency: AsyncOperation<DependencyOutput, DependencyFailure>,
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mapOutput: @escaping (DependencyOutput) -> Result<Output, Failure>,
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mapFailure: @escaping (DependencyFailure) -> Failure) {
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super.init()
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cancelOnCancellation(of: dependency)
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dependencyObservation = dependency.subscribe { [weak self] in
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switch mapOutput($0) {
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case let .success(result):
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self?.handle(result: result)
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case let .failure(error):
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self?.handle(error: error)
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}
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} onFailure: { [weak self] in
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self?.handle(error: mapFailure($0))
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}
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addDependency(dependency) // keeps strong reference to dependency as well
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state = .isReady
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}
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}
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public extension AsyncOperation {
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func map<NewOutput, NewFailure: Error>(mapOutput: @escaping (Output) -> Result<NewOutput, NewFailure>,
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mapFailure: @escaping (Failure) -> NewFailure)
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-> AsyncOperation<NewOutput, NewFailure> {
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MapAsyncOperation(dependency: self,
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mapOutput: mapOutput,
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mapFailure: mapFailure)
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}
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func map<NewOutput>(mapOutput: @escaping (Output) -> NewOutput) -> AsyncOperation<NewOutput, Failure> {
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MapAsyncOperation(dependency: self,
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mapOutput: { .success(mapOutput($0)) },
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mapFailure: { $0 })
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}
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}
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