neon/sys/lifecycle.rs
1//! # Environment life cycle APIs
2//!
3//! These APIs map to the life cycle of a specific "Agent" or self-contained
4//! environment. If a Neon module is loaded multiple times (Web Workers, worker
5//! threads), these API will be handle data associated with a specific instance.
6//!
7//! See the [N-API Lifecycle][npai-docs] documentation for more details.
8//!
9//! [napi-docs]: https://nodejs.org/api/n-api.html#n_api_environment_life_cycle_apis
10
11use std::{mem::MaybeUninit, os::raw::c_void, ptr};
12
13use super::{bindings as napi, raw::Env};
14
15/// # Safety
16/// `env` must point to a valid `napi_env` for this thread
17pub unsafe fn set_instance_data<T: Send + 'static>(env: Env, data: T) -> *mut T {
18 let data = Box::into_raw(Box::new(data));
19
20 napi::set_instance_data(env, data.cast(), Some(drop_box::<T>), ptr::null_mut()).unwrap();
21
22 data
23}
24
25/// # Safety
26/// * `T` must be the same type used in `set_instance_data`
27/// * Caller must ensure reference does not outlive `Env`
28/// * Return value may be `null`
29/// * `env` must point to a valid `napi_env` for this thread
30pub unsafe fn get_instance_data<T: Send + 'static>(env: Env) -> *mut T {
31 let mut data = MaybeUninit::uninit();
32
33 napi::get_instance_data(env, data.as_mut_ptr()).unwrap();
34
35 data.assume_init().cast()
36}
37
38unsafe extern "C" fn drop_box<T>(_env: Env, data: *mut c_void, _hint: *mut c_void) {
39 drop(Box::<T>::from_raw(data.cast()));
40}