Deep Dive
Grove - Deep Dive
Rust/WASM extension host, WebAssembly runtime, and sandboxed extension execution
Grove - Deep Dive
Grove is a native, sandboxed Rust/WASM extension host that runs VS Code extensions compiled to WebAssembly, complementing the Node.js-based Cocoon host.
Architecture 🏗️
Five-layer design: extension host controller, WASM runtime, VS Code API bridge, transport layer, and shared utilities.
Layer Breakdown
| Layer | Key Modules |
|---|---|
| Extension Host Controller | ExtensionHost.rs, ExtensionManager.rs, Activation.rs, Lifecycle.rs, APIBridge.rs |
| WASM Runtime | Runtime.rs (WASMtime engine), ModuleLoader.rs, MemoryManager.rs, HostBridge.rs |
| Transport | gRPCTransport.rs, IPCTransport.rs, WASMTransport.rs with pluggable Strategy.rs trait |
| API | vscode.rs, types.rs matching VS Code TypeScript types |
| Protocol/Services | SpineConnection.rs, host services, shared utilities |
Data Flow 🔄
- Mountain sends
ActivateExtensionvia Grove.proto - Grove loads extension manifest and compiles WASM module
- WASM runtime instantiates the module with host functions
- Extension calls host functions (e.g.
vscode.workspace.readFile) - HostBridge dispatches, Grove forwards service call to Mountain via Transport
- Mountain returns result, passed back through WASM to extension
WASM Runtime ⚡
- Engine: WASMtime with per-extension memory limits
- Module loading: Compilation and caching of WASM files
- Memory management: Linear memory allocation and bounds enforcement
- Host bridge: Registered functions available to extension WASM code
Transport Options 🚚
Selectable via Cargo features:
| Feature | Description |
|---|---|
grpc | gRPC via Mountain (default) |
wasm | WASMtime runtime (default) |
ipc | Unix/Windows IPC transport (Unix only) |
all | All features enabled |
Configuration ⚙️
| Option | Default | Description |
|---|---|---|
| Standalone mode | off | Run without Mountain for testing (--standalone) |
| Extension path | unset | Load specific extension directly (--extension) |
| Memory limit | platform default | Per-extension WASM memory ceiling |
| WASM target | wasm32-wasi | Extensions must target this ABI |
Integration 🔗
| Element | Direction | Mechanism | Description |
|---|---|---|---|
| Mountain | Bidirectional | gRPC via Grove.proto | Extension activation and API call forwarding |
| Vine | Inbound | Protocol definition | Grove.proto extends Vine service definitions |
| Cocoon | Sibling | Shared API surface | Same VS Code API surface for portability |