BackgroundSerialPersistence

BackgroundSerialPersistence.swift

import Foundation
import SwiftData

/// ```swift
/// // One operation one instance of BackgroundSerialPersistenceActor class
///  let actor = BackgroundSerialPersistenceActor<MyModel>(container: modelContainer)
///
///  Task {
///      let data = try? await actor.fetchData()
///  }
///  ```
@available(iOS 17, *)
public actor BackgroundSerialPersistenceActor<T: PersistentModel>: ModelActor {

    public let modelContainer: ModelContainer
    public let modelExecutor: any ModelExecutor
    private var context: ModelContext { modelExecutor.modelContext }

    public init(container: ModelContainer) {
        self.modelContainer = container
        let context = ModelContext(modelContainer)
        modelExecutor = DefaultSerialModelExecutor(modelContext: context)
    }

    public func fetchData(descriptor: FetchDescriptor<T>) throws -> [T] {
        let list: [T] = try context.fetch(descriptor)
        return list
    }

    public func fetchData(predicate: Predicate<T>? = nil) throws -> [T] {
        let fetchDescriptor = FetchDescriptor<T>(predicate: predicate)
        let list: [T] = try context.fetch(fetchDescriptor)
        return list
    }

    public func save(data: T) throws {
        context.insert(data)
        try context.save()
    }

    public func remove(predicate: Predicate<T>? = nil) throws {
        try context.delete(model: T.self, where: predicate)
    }
}