Platrium App

The Platrium App for macOS and iOS is a thin, native Swift shell. Rather than building a massive monolithic application, the native app acts primarily as a Host Environment that binds together several high-performance libraries and registers the system extensions (like the File Provider) with the Apple operating system.

The Dependency Chain

To keep the native app lightweight, all heavy lifting is delegated to dedicated modules and packages. Here is how the dependencies are linked together within the Xcode project:

1. Platrium SDK (Rust/WASM): The core business logic, cryptography, and high-speed network streaming are handled by our Rust SDK. The internals of how we compile this into an Apple XCFramework with UniFFI bindings are detailed in the Apple Darwin SDK Internals.
2. Platrium GraphQL Package: All API requests and schema definitions are encapsulated in a generated Swift package.
3. Apollo iOS: We use the Apollo iOS GraphQL client to execute queries, manage normalized caching, and handle network transport for the API.
4. SwiftUI Host: The actual user interface (for login, settings, and status) is built using SwiftUI, which simply observes state from the underlying packages.

Hosting the File Provider

The most critical job of the native app is to host and register the FileProviderReplicatedExtension.

Because Apple enforces strict security sandboxes, a File Provider Extension cannot run independently—it must be bundled inside a host .app.

When the user logs in, the host app uses the NSFileProviderManager API to register a new domain (essentially a virtual hard drive) with macOS. It securely passes the authentication tokens (like the JWT session and tenant IDs) into the shared App Group keychain. Once registered, macOS completely takes over, launching the FSExtension process in the background and asking it to populate the files!