zeus
29 lines
1000 B
Swift
29 lines
1000 B
Swift
extension ValueReducers {
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// swiftlint:disable line_length
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/// A `ValueReducer` that handles ``ValueObservation`` events.
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///
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/// See ``ValueObservation/handleEvents(willStart:willFetch:willTrackRegion:databaseDidChange:didReceiveValue:didFail:didCancel:)``
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/// and ``ValueObservation/print(_:to:)``.
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public struct Trace<Base: _ValueReducer>: _ValueReducer {
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var base: Base
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let willFetch: () -> Void
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let didReceiveValue: (Base.Value) -> Void
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public mutating func _value(_ fetched: Base.Fetched) throws -> Base.Value? {
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guard let value = try base._value(fetched) else {
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return nil
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}
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didReceiveValue(value)
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return value
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}
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}
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// swiftlint:enable line_length
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}
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extension ValueReducers.Trace: ValueReducer where Base: ValueReducer {
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public func _fetch(_ db: Database) throws -> Base.Fetched {
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willFetch()
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return try base._fetch(db)
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}
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}
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