Function NewInstance

instance.go:24–52

NewInstance instantiates a WebAssembly `module` with the `imports` provided. This function will attempt to create a new wasm instance given the provided imports. This can fail if the wrong number of imports are specified, the imports aren't of the right type, or for other resource-related issues.

(store Storelike, module *Module, imports []AsExtern)

// This will also run the `start` function of the instance, returning an error
// if it traps.
func NewInstance(store Storelike, module *Module, imports []AsExtern) (*Instance, error) {
	importsRaw := make([]C.wasmtime_extern_t, len(imports))
	for i, imp := range imports {
		importsRaw[i] = imp.AsExtern()
	}
	var val C.wasmtime_instance_t
	err := enterWasm(store, func(trap **C.wasm_trap_t) *C.wasmtime_error_t {
		var imports *C.wasmtime_extern_t
		if len(importsRaw) > 0 {
			imports = (*C.wasmtime_extern_t)(unsafe.Pointer(&importsRaw[0]))
		}
		return C.wasmtime_instance_new(
			store.Context(),
			module.ptr(),
			imports,
			C.size_t(len(importsRaw)),
			&val,
			trap,
		)
	})
	runtime.KeepAlive(store)
	runtime.KeepAlive(module)
	runtime.KeepAlive(imports)
	runtime.KeepAlive(importsRaw)
	if err != nil {
		return nil, err
	}
	return mkInstance(val), nil
}

func mkInstance(val C.wasmtime_instance_t) *Instance {
	return &Instance{val}