Method generate_host_function_builder

cmd/gravity/src/codegen/imports.rs:448–500

(
        &self,
        method: &InterfaceMethod,
        // The name of the parameter representing the interface instance
        // in the generated function.
        param_name: &GoIdentifier,
   

    }

    fn generate_host_function_builder(
        &self,
        method: &InterfaceMethod,
        // The name of the parameter representing the interface instance
        // in the generated function.
        param_name: &GoIdentifier,
    ) -> Tokens<Go> {
        let func_name = &method.name;

        let wasm_sig = self
            .resolve
            .wasm_signature(AbiVariant::GuestImport, &method.wit_function);
        let result = if wasm_sig.results.is_empty() {
            GoResult::Empty
        } else if wasm_sig.results.len() == 1 {
            GoResult::Anon(resolve_wasm_type(&wasm_sig.results[0]))
        } else {
            todo!("implement handling of wasm signatures with multiple results");
        };
        let mut f = Func::import(param_name, result, self.sizes);

        // Magic
        wit_bindgen_core::abi::call(
            self.resolve,
            AbiVariant::GuestImport,
            LiftLower::LiftArgsLowerResults,
            &method.wit_function,
            &mut f,
            // async is not currently supported
            false,
        );

        // Collect all host function parameters into a single list so
        // that the join produces correct commas even when there are no
        // WIT-level parameters (only ctx and mod).
        let mut all_params: Vec<Tokens<Go>> = vec![
            quote! { ctx $CONTEXT_CONTEXT },
            quote! { mod $WAZERO_API_MODULE },
        ];
        for arg in f.args() {
            all_params.push(quote! { $arg uint32 });
        }

        quote! {
            NewFunctionBuilder().
            WithFunc(func(
                $(for param in all_params join (,$['\r']) => $param),
            ) $(f.result()){
                $(f.body())
            }).
            Export($(quoted(func_name))).
        }
    }
}

#[cfg(test)]