Sample CodemacOSReviewed 2026-07-21View on Apple Developer

Running Linux in a Virtual Machine

At a glance

Item Summary
Purpose Run a Linux operating system on your Mac using the Virtualization framework.
App architecture A Swift sample centered on Delegate, with direct use of Virtualization.
Main patterns Delegate or data-source callbacks
Project style 1 scanned source file(s) across Swift, organized around ranked entry, type, and file boundaries.
Execution model Source-visible boundaries: RunLoop.main; none alone proves a background thread.
State/event model No structured observation or publisher-scheduling marker indexed.
Key frameworks/packages Foundation, Virtualization; these are source dependencies, not architecture labels.

Project structure

Source bundle/
├── LinuxVirtualMachine/
│   ├── main.swift
│   └── LinuxVirtualMachine.entitlements
├── Configuration/
│   └── SampleCode.xcconfig
└── LinuxVirtualMachine.xcodeproj/
    ├── .xcodesamplecode.plist
    └── project.pbxproj

Structure observations

  • Architecturally prominent files are ranked from entry points and role-named declarations; resource-only paths are omitted.
  • Primary languages: Swift.
  • The verified tree contains 4 project/configuration file(s) and 1 source declaration(s).

Overall architecture

Reference code

LinuxVirtualMachine/main.swift:53 — architecture anchor

class Delegate: NSObject {
}

Interpretation

The arrows summarize the source-visible entry, role-named types or folders, and framework direction; when nodes come from structural folders, the sequence is a high-level interpretation rather than proof that every adjacent node calls the next. Ownership is claimed only where the next section cites a stored property or assignment. The diagram is intentionally limited to the dominant path into Virtualization.

Ownership and state

Ownership evidence

LinuxVirtualMachine/main.swift:17 — stored dependency or nearest verified ownership anchor

let kernelURL = URL(fileURLWithPath: CommandLine.arguments[1], isDirectory: false)
Owner Object or state Relationship Mutation authority
main URL (kernelURL) owns value state Initialized by the owner; the binding is immutable
main URL (initialRamdiskURL) owns value state Initialized by the owner; the binding is immutable
main VZVirtualMachineConfiguration (configuration) creates and retains Initialized by the owner; the binding is immutable
main VZVirtualMachine (virtualMachine) creates and retains Initialized by the owner; the binding is immutable

Composition arrows indicate a source-visible construction expression or locally owned value state; aggregation means the owner stores or receives a dependency without proving exclusive lifetime ownership.

Concurrency, scheduling, and thread safety

Evidence limit: actor isolation, async/await, or Task creation does not by itself prove background-thread execution; Sendable conformance alone does not prove thread-safe mutation.

Concern Source mechanism Verified placement or handoff Evidence
Run-loop scheduling RunLoop.main The source refers to the main thread’s run loop, a scheduling/liveness boundary rather than actor isolation. LinuxVirtualMachine/main.swift:49

@MainActor/MainActor.run, DispatchQueue.main, and RunLoop.main are reported as distinct isolation, queue, and event-loop mechanisms. A plain Task is kept separate from Task.detached; neither is labeled as a background thread.

Reference code

LinuxVirtualMachine/main.swift:49 — representative execution boundary

RunLoop.main.run(until: Date.distantFuture)

// MARK: - Virtual Machine Delegate

class Delegate: NSObject {
}

State propagation, frameworks, and dependencies

Evidence limit: an import proves a source-level compilation dependency at the cited line; it does not prove runtime use, architectural adoption, or whether a Swift package is a direct application dependency.

Category Mechanism or module Verified role Evidence
Source import Foundation The cited file imports this module; runtime use and architectural role are not inferred. LinuxVirtualMachine/main.swift:8
Source import Virtualization The cited file imports this module; runtime use and architectural role are not inferred. LinuxVirtualMachine/main.swift:9

receive(on:) describes downstream delivery scheduling, while subscribe(on:) describes upstream subscription/request/cancel scheduling. An import Combine alone establishes neither behavior nor a Store, reducer, Redux, or other application architecture.

Class and protocol design

LinuxVirtualMachine/main.swift:53 — representative type boundary

class Delegate: NSObject {
}
Type Responsibility Depends on or conforms to
Delegate Receives callback-driven events NSObject

No local protocol conformance is claimed as protocol-oriented design; external framework conformances are listed only as dependencies.

Access control

Symbol Access Verified effect Likely rationale
Delegate (LinuxVirtualMachine/main.swift:53) implicit internal No explicit modifier means the Swift declaration is internal to the module. Inference: app-target collaboration needs no exported library surface.

Reference code

LinuxVirtualMachine/main.swift:53 — representative boundary

class Delegate: NSObject {
}

Swift declarations without a modifier are internal; explicit private, fileprivate, private(set), public, or open entries above are interpreted by language semantics. Objective-C/C samples instead rely on header and implementation boundaries, which are not equivalent to Swift lexical privacy.

Logic ownership and placement

Logic Owning type or file Placement rationale
Receives callback-driven events Delegate The source’s Delegate suffix makes this role explicit.

Design patterns

Pattern Source evidence Purpose or tradeoff
Delegate or data-source callbacks LinuxVirtualMachine/main.swift:56 Callback protocols invert event delivery back into the sample’s owner.

Naming conventions

  • Types: Delegate: Delegate.
  • Protocols: no local protocol declaration in the scanned source.
  • Methods: guestDidStop, createBootLoader, createConsoleConfiguration, printUsageAndExit.
  • Files: feature/project roles rather than a strict one-type-per-file rule.

Architecture takeaways

  • Delegate is the main source-visible entry or composition anchor for this sample.
  • Framework work reaches Virtualization through a deliberately small high-level chain; the detailed API graph remains inside the cited implementation files.
  • Stored-property evidence identifies lifecycle collaboration; it does not by itself prove exclusive object ownership.
  • Access-control conclusions separate verified language visibility from the likely design rationale.
  • The source does not justify labeling the design protocol-oriented.

Source map

Source file Relevant symbols
LinuxVirtualMachine/main.swift Delegate, Cited implementation, RunLoop.main, Foundation, Virtualization