container/Sources/Containerization/VirtualMachineInstance.swift

//===----------------------------------------------------------------------===//
// Copyright © 2025 Apple Inc. and the containerization project authors. All rights reserved.
//
// 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
//
//   https://www.apache.org/licenses/LICENSE-2.0
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// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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//===----------------------------------------------------------------------===//

import Foundation

/// The runtime state of the virtual machine instance.
public enum VirtualMachineInstanceState: Sendable {
    case starting
    case running
    case stopped
    case stopping
    case unknown
}

/// A manager that can spawn and manage a virtual machine.
public protocol VirtualMachineInstance: Sendable {
    associatedtype Agent: VirtualMachineAgent

    // The state of the virtual machine.
    var state: VirtualMachineInstanceState { get }

    var mounts: [AttachedFilesystem] { get }
    /// Dial the Agent. It's up the VirtualMachineInstance to determine
    /// what port the agent is listening on.
    func dialAgent() async throws -> Agent
    /// Dial a vsock port in the guest.
    func dial(_ port: UInt32) async throws -> FileHandle
    /// Listen on a host vsock port.
    func listen(_ port: UInt32) throws -> ConnectionStream
    /// Stop listening on a vsock port.
    func stopListen(_ port: UInt32) throws
    /// Start the virtual machine.
    func start() async throws
    /// Stop the virtual machine.
    func stop() async throws
}