Trait TraitBridgeGenerator 

pub trait TraitBridgeGenerator {
    // Required methods
    fn foreign_object_type(&self) -> &str;
    fn bridge_imports(&self) -> Vec<String>;
    fn gen_sync_method_body(
        &self,
        method: &MethodDef,
        spec: &TraitBridgeSpec<'_>,
    ) -> String;
    fn gen_async_method_body(
        &self,
        method: &MethodDef,
        spec: &TraitBridgeSpec<'_>,
    ) -> String;
    fn gen_constructor(&self, spec: &TraitBridgeSpec<'_>) -> String;
    fn gen_registration_fn(&self, spec: &TraitBridgeSpec<'_>) -> String;

    // Provided method
    fn async_trait_is_send(&self) -> bool { ... }
}

Backend-specific trait bridge generation.

Each binding backend (PyO3, NAPI-RS, wasm-bindgen, etc.) implements this trait to provide the language-specific parts of bridge codegen. The shared functions in this module call these methods to fill in the backend-dependent pieces.

Required Methods

fn foreign_object_type(&self) -> &str

The type of the wrapped foreign object (e.g., "Py<PyAny>", "ThreadsafeFunction").

fn bridge_imports(&self) -> Vec<String>

Additional use imports needed for the bridge code.

fn gen_sync_method_body( &self, method: &MethodDef, spec: &TraitBridgeSpec<'_>, ) -> String

Generate the body of a synchronous method bridge.

The returned string is inserted inside the trait impl method. It should call through to the foreign object and convert the result.

fn gen_async_method_body( &self, method: &MethodDef, spec: &TraitBridgeSpec<'_>, ) -> String

Generate the body of an async method bridge.

The returned string is the body of a Box::pin(async move { ... }) block.

fn gen_constructor(&self, spec: &TraitBridgeSpec<'_>) -> String

Generate the constructor body that validates and wraps the foreign object.

Should check that the foreign object provides all required methods and return Self { ... } on success.

fn gen_registration_fn(&self, spec: &TraitBridgeSpec<'_>) -> String

Generate the complete registration function including attributes, signature, and body.

Each backend needs different function signatures (PyO3 takes py: Python, NAPI takes #[napi] with JS params, FFI takes extern "C" with raw pointers), so the generator owns the full function.

Provided Methods

fn async_trait_is_send(&self) -> bool

Whether the #[async_trait] macro should require Send on its futures.

Returns true (default) for most targets. WASM is single-threaded so its trait bounds don’t include Send; implementors should return false there.

Implementors