Finding devices with precision

At a glance

Project structure

Source bundle/
├── NIJetpack/
│   ├── NIJetpackApp.swift
│   ├── NISessionManager.swift
│   ├── Views/
│   │   ├── NICameraAssistanceView.swift
│   │   ├── NIContentView.swift
│   │   ├── NIUnsupportedDeviceView.swift
│   │   └── NICoachingOverlay.swift
│   ├── MultiPeerConnectivitySupport/
│   │   └── MPCSession.swift
│   ├── MathUtilities.swift
│   └── Info.plist
├── Configuration/
│   └── SampleCode.xcconfig
└── NIJetpack.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 14 source declaration(s).

Overall architecture

flowchart LR
    N1["NIJetpackApp"]
    N2["NIContentView"]
    N3["Coordinator"]
    N4["MPCSession"]
    N5["NearbyInteraction APIs"]
    N1 --> N2
    N2 --> N3
    N3 --> N4
    N4 --> N5

Reference code

NIJetpack/NIJetpackApp.swift:10 — architecture anchor

@main
struct NIJetpackApp: App {
    var body: some Scene {
        WindowGroup {
            NIContentView()
        }
    }
}

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 Nearby Interaction.

Ownership and state

classDiagram
    NISessionManager o-- FindingMode : findingMode
    NISessionManager *-- DispatchQueue : sessionQueue
    NISessionManager o-- MeasurementQualityEstimator : qualityEstimator
    NISessionManager o-- NISession : session

Ownership evidence

NIJetpack/NISessionManager.swift:17 — stored dependency or nearest verified ownership anchor

class NISessionManager: NSObject, NISessionDelegate, ObservableObject, ARSessionDelegate {
    // ...
    let findingMode: FindingMode
    // ...
}

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.

@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

NIJetpack/MultiPeerConnectivitySupport/MPCSession.swift:45 — representative execution boundary

class MPCSession: NSObject, MCSessionDelegate, MCNearbyServiceBrowserDelegate, MCNearbyServiceAdvertiserDelegate {
    // ...
        mpcSessionSerialQueue = DispatchQueue(label: "NIJetpack.mpcQueue", qos: .default)
    // ...
}

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.

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

NIJetpack/NIJetpackApp.swift:11 — representative type boundary

@main
struct NIJetpackApp: App {
    // ...
            NIContentView()
    // ...
}

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

Access control

Reference code

NIJetpack/MultiPeerConnectivitySupport/MPCSession.swift:20 — representative boundary

class MPCSession: NSObject, MCSessionDelegate, MCNearbyServiceBrowserDelegate, MCNearbyServiceAdvertiserDelegate {
    // ...
    private let serviceString: String
    // ...
}

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

Design patterns

Naming conventions

• Types: App: NIJetpackApp; Coordinator: Coordinator; Manager: NISessionManager; Session: MPCSession; View: NIARView, NICameraAssistanceView, NIContentView, NIUnsupportedDeviceView.
• Protocols: no local protocol declaration in the scanned source.
• Methods: invalidate, startup, startupMPC, tearDownMpc, setARSession, updateConnectedPeer, connectedToPeer, disconnectedFromPeer.
• Files: NIJetpack/NIJetpackApp.swift, NIJetpack/NISessionManager.swift, NIJetpack/Views/NICameraAssistanceView.swift, NIJetpack/Views/NIContentView.swift, NIJetpack/MultiPeerConnectivitySupport/MPCSession.swift, NIJetpack/Views/NIUnsupportedDeviceView.swift.

Architecture takeaways

• NIJetpackApp is the main source-visible entry or composition anchor for this sample.
• Framework work reaches SwiftUI, NearbyInteraction, ARKit, MultipeerConnectivity 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

• Official Apple documentation