Files
WebApp/Pods/FirebaseFirestore/Firestore/Swift/Source/Codable/ServerTimestamp.swift
2025-09-20 17:13:38 +08:00

110 lines
3.2 KiB
Swift

/*
* Copyright 2019 Google LLC
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
@_exported import class FirebaseCore.Timestamp
/// A type that can initialize itself from a Firestore Timestamp, which makes
/// it suitable for use with the `@ServerTimestamp` property wrapper.
///
/// Firestore includes extensions that make `Timestamp` and `Date` conform to
/// `ServerTimestampWrappable`.
public protocol ServerTimestampWrappable {
/// Creates a new instance by converting from the given `Timestamp`.
///
/// - Parameter timestamp: The timestamp from which to convert.
static func wrap(_ timestamp: Timestamp) throws -> Self
/// Converts this value into a Firestore `Timestamp`.
///
/// - Returns: A `Timestamp` representation of this value.
static func unwrap(_ value: Self) throws -> Timestamp
}
extension Date: ServerTimestampWrappable {
public static func wrap(_ timestamp: Timestamp) throws -> Self {
return timestamp.dateValue()
}
public static func unwrap(_ value: Self) throws -> Timestamp {
return Timestamp(date: value)
}
}
extension Timestamp: ServerTimestampWrappable {
public static func wrap(_ timestamp: Timestamp) throws -> Self {
return timestamp as! Self
}
public static func unwrap(_ value: Timestamp) throws -> Timestamp {
return value
}
}
/// A property wrapper that marks an `Optional<Timestamp>` field to be
/// populated with a server timestamp. If a `Codable` object being written
/// contains a `nil` for an `@ServerTimestamp`-annotated field, it will be
/// replaced with `FieldValue.serverTimestamp()` as it is sent.
///
/// Example:
/// ```
/// struct CustomModel {
/// @ServerTimestamp var ts: Timestamp?
/// }
/// ```
///
/// Then writing `CustomModel(ts: nil)` will tell server to fill `ts` with
/// current timestamp.
@propertyWrapper
public struct ServerTimestamp<Value>: Codable
where Value: ServerTimestampWrappable & Codable {
var value: Value?
public init(wrappedValue value: Value?) {
self.value = value
}
public var wrappedValue: Value? {
get { value }
set { value = newValue }
}
// MARK: Codable
public init(from decoder: Decoder) throws {
let container = try decoder.singleValueContainer()
if container.decodeNil() {
value = nil
} else {
value = try Value.wrap(container.decode(Timestamp.self))
}
}
public func encode(to encoder: Encoder) throws {
var container = encoder.singleValueContainer()
if let value {
try container.encode(Value.unwrap(value))
} else {
try container.encode(FieldValue.serverTimestamp())
}
}
}
extension ServerTimestamp: Equatable where Value: Equatable {}
extension ServerTimestamp: Hashable where Value: Hashable {}
extension ServerTimestamp: Sendable where Value: Sendable {}