blob: ac2ebe1ac868118dd115ff8224b9a69c8a43b9b5 [file] [log] [blame]
// Copyright 2019 The Fuchsia Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
//! A library with a futures-aware waitgroup.
use futures::future::{self, AbortHandle, Abortable, Pending};
enum Never {}
/// A futures-aware wait group enabling one task to await the completion of many others.
pub struct WaitGroup {
members: Vec<Abortable<Pending<Never>>>,
/// A member of a `WaitGroup` that each task should hold, and drop when it is complete.
pub struct Waiter {
handle: AbortHandle,
impl Drop for Waiter {
fn drop(&mut self) {
impl WaitGroup {
/// Creates a new waitgroup with no tasks to wait on.
pub fn new() -> Self {
Self { members: vec![] }
/// Returns a `Waiter` handle to give to tasks that must be waited on.
pub fn new_waiter(&mut self) -> Waiter {
let (fut, handle) = future::abortable(future::pending::<Never>());
Waiter { handle }
/// A wait that completes when all `Waiter`s vended by `new_waiter()` are dropped.
pub async fn wait(&mut self) {
let _ = future::join_all(self.members.split_off(0)).await;