Grove - Deep Dive

Grove provides the technical foundation Rust/WASM extension host within the Land project. Grove provides a native, sandboxed environment for running VS Code extensions compiled to WebAssembly or native Rust, complementing the Node.js-based Cocoon host.

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Architecture

Grove is organized into five layers: the extension host controller that manages the lifecycle, the WASM runtime that provides sandboxed execution, the VS Code API bridge that presents the standard extension API, the transport layer that communicates with Mountain, and shared utility modules.

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Key Modules

Path	Description
Source/lib.rs	Library root; exports public API for integration and testing
Source/main.rs	Binary entry point; parses CLI and starts the extension host
Source/Binary/	CLI argument handling and standalone vs connected mode selection
Source/Host/ExtensionHost.rs	Main controller: coordinates extension loading, activation, and service provision
Source/Host/ExtensionManager.rs	Extension discovery, manifest parsing, and loading
Source/Host/Activation.rs	Activation event processing (onLanguage, onCommand, etc.)
Source/Host/Lifecycle.rs	Extension activate/deactivate lifecycle management
Source/Host/APIBridge.rs	VS Code API facade implementation for Rust/WASM extensions
Source/WASM/Runtime.rs	WASMtime engine and store management with memory limits
Source/WASM/ModuleLoader.rs	WASM module compilation, caching, and instantiation
Source/WASM/MemoryManager.rs	WASM linear memory allocation and bounds enforcement
Source/WASM/HostBridge.rs	Host function exports to WASM modules
Source/WASM/FunctionExport.rs	Registered host functions available to extension WASM code
Source/Transport/Strategy.rs	Transport strategy trait for pluggable communication
Source/Transport/gRPCTransport.rs	gRPC communication with Mountain via tonic
Source/Transport/IPCTransport.rs	Unix/Windows IPC transport for same-host communication
Source/Transport/WASMTransport.rs	Direct in-process WASM function call transport
Source/Protocol/SpineConnection.rs	Spine protocol client for extension host coordination

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Data Flow

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Integration Points

Connecting Element	Direction	Mechanism	Description
Mountain	Bidirectional	gRPC via Vine	Mountain activates extensions; Grove forwards API calls back to Mountain
Cocoon	Sibling	Shared API surface	Grove implements the same VS Code API surface as Cocoon for extension portability

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Configuration

Option	CLI Flag / Feature	Default	Description
Standalone mode	--standalone	off	Run without Mountain connection for testing
Extension path	--extension	unset	Load a specific extension directly
Transport	feature flag	gRPC	Select grpc, ipc, or wasm transport via Cargo features
Memory limit	runtime config	platform default	Per-extension WASM memory ceiling enforced by WASMtime
WASM build target	wasm32-wasi	native	Extensions must target wasm32-wasi for WASM mode

Cargo features

Feature	Description
grpc	gRPC transport support (included in default)
wasm	WASMtime WASM runtime (included in default)
ipc	Unix/Windows IPC transport (Unix only)
all	All features enabled