68 lines
1.9 KiB
Swift
68 lines
1.9 KiB
Swift
/*
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* Copyright 2019 Google
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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#if SWIFT_PACKAGE
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@_exported import FirebaseFirestoreInternalWrapper
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#else
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@_exported import FirebaseFirestoreInternal
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#endif // SWIFT_PACKAGE
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/// Wraps an `Optional` field in a `Codable` object such that when the field
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/// has a `nil` value it will encode to a null value in Firestore. Normally,
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/// optional fields are omitted from the encoded document.
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///
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/// This is useful for ensuring a field is present in a Firestore document,
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/// even when there is no associated value.
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@propertyWrapper
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public struct ExplicitNull<Value> {
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var value: Value?
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public init(wrappedValue value: Value?) {
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self.value = value
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}
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public var wrappedValue: Value? {
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get { value }
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set { value = newValue }
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}
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}
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extension ExplicitNull: Equatable where Value: Equatable {}
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extension ExplicitNull: Hashable where Value: Hashable {}
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extension ExplicitNull: Encodable where Value: Encodable {
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public func encode(to encoder: Encoder) throws {
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var container = encoder.singleValueContainer()
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if let value = value {
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try container.encode(value)
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} else {
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try container.encodeNil()
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}
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}
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}
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extension ExplicitNull: Decodable where Value: Decodable {
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public init(from decoder: Decoder) throws {
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let container = try decoder.singleValueContainer()
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if container.decodeNil() {
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value = nil
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} else {
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value = try container.decode(Value.self)
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}
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}
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}
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