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40 lines
1.2 KiB
Swift
40 lines
1.2 KiB
Swift
/*
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Copyright (C) 2015 Apple Inc. All Rights Reserved.
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See LICENSE.txt for this sample’s licensing information
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Abstract:
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The file shows how to make an OperationCondition that composes another OperationCondition.
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*/
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import Foundation
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/**
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A simple condition that causes another condition to not enqueue its dependency.
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This is useful (for example) when you want to verify that you have access to
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the user's location, but you do not want to prompt them for permission if you
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do not already have it.
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*/
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struct SilentCondition<T: OperationCondition>: OperationCondition {
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let condition: T
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static var name: String {
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return "Silent<\(T.name)>"
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}
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static var isMutuallyExclusive: Bool {
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return T.isMutuallyExclusive
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}
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init(condition: T) {
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self.condition = condition
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}
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func dependencyForOperation(operation: Operation) -> NSOperation? {
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// Returning nil means we will never a dependency to be generated.
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return nil
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}
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func evaluateForOperation(operation: Operation, completion: OperationConditionResult -> Void) {
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condition.evaluateForOperation(operation, completion: completion)
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}
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}
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