ADR 001: Dependency Injection for Assets (IAssetProvider)

Status

Accepted

Context

The Enigma Machine Core is designed to be universal, supporting platforms from high-end Linux systems to low-end bare-metal microcontrollers and WebAssembly (WASM). Loading configuration files (TOML) directly from the filesystem (std::ifstream) creates a hard dependency on an OS-level filesystem, which is absent in many of our target environments (e.g., WASM, Zephyr RTOS).

Decision

We will decouple the Enigma Engine from the physical filesystem by introducing the IAssetProvider interface.

1. Interface: IAssetProvider defines a single loadAsset(assetName) method that returns a std::string containing the asset's content.
2. Decoupling: The EnigmaMachine and its components will not perform file I/O. Instead, they will receive an IAssetProvider (Dependency Injection) and use it to retrieve configuration data.
3. Implementations:
   • FileAssetProvider: For platforms with a filesystem (CLI, Desktop).
   • MemoryAssetProvider (Planned): For platforms like WASM or Embedded where assets are pre-loaded or linked into the binary.

Consequences

• Portability: The engine can now run on platforms without a filesystem by providing a custom provider.
• Testability: Unit tests can use a mock provider to simulate configuration data without relying on disk files.
• Complexity: Slightly increases initialization complexity as a provider must be instantiated and passed to the machine.