Building a Simple USB Driver

At a glance

Project structure

Source bundle/
├── SimpleUSBInterfaceDriver/
│   ├── SimpleUSBInterfaceDriver.h
│   ├── SimpleUSBInterfaceDriver.cpp
│   ├── debug.h
│   └── Info.plist
├── Configuration/
│   └── SampleCode.xcconfig
└── SimpleUSBInterfaceDriver.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: C++, C/Objective-C header.
• The verified tree contains 4 project/configuration file(s) and 1 source declaration(s).

Overall architecture

flowchart LR
    N1["SimpleUSBInterfaceDriver"]
    N2["IOKit APIs"]
    N1 --> N2

Reference code

SimpleUSBInterfaceDriver/SimpleUSBInterfaceDriver.h:34 — architecture anchor

#ifndef _SimpleUSBInterfaceDriver_h_
class SimpleUSBInterfaceDriver: public IOService
{
    OSDeclareDefaultStructors(SimpleUSBInterfaceDriver)
    // ...
};
#endif

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 Kernel.

Ownership and state

classDiagram
    SimpleUSBInterfaceDriver --> KernelAPIs : uses

Ownership evidence

SimpleUSBInterfaceDriver/SimpleUSBInterfaceDriver.cpp:15 — stored dependency or nearest verified ownership anchor

OSDefineMetaClassAndStructors(SimpleUSBInterfaceDriver, IOService);

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.

No source-visible execution, scheduling, or synchronization boundary was found in the indexed source.

@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.

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

SimpleUSBInterfaceDriver/SimpleUSBInterfaceDriver.h:34 — representative type boundary

#ifndef _SimpleUSBInterfaceDriver_h_
class SimpleUSBInterfaceDriver: public IOService
{
    OSDeclareDefaultStructors(SimpleUSBInterfaceDriver)
    // ...
};
#endif

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

Access control

Reference code

SimpleUSBInterfaceDriver/SimpleUSBInterfaceDriver.h:34 — representative boundary

#ifndef _SimpleUSBInterfaceDriver_h_
class SimpleUSBInterfaceDriver: public IOService
{
    // ...
};
#endif

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: feature-specific names rather than reusable layer suffixes.
• Protocols: no local protocol declaration in the scanned source.
• Methods: no representative method name extracted from the architectural files.
• Files: SimpleUSBInterfaceDriver/SimpleUSBInterfaceDriver.h.

Architecture takeaways

• SimpleUSBInterfaceDriver is the main source-visible entry or composition anchor for this sample.
• Framework work reaches IOKit 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