base/src/async_types.rs

// Copyright 2020 The Chromium OS Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

use crate::AsRawDescriptor;
use cros_async::IntoAsync;
use std::os::unix::io::{AsRawFd, RawFd};

/// Like `cros_async::IntoAsync`, except for use with crosvm's AsRawDescriptor
/// trait object family.
pub trait DescriptorIntoAsync: AsRawDescriptor {}

/// To use an IO struct with cros_async, the type must be marked with
/// DescriptorIntoAsync (to signify it is suitable for use with async
/// operations), and then wrapped with this type.
pub struct DescriptorAdapter<T: DescriptorIntoAsync>(pub T);
impl<T> AsRawFd for DescriptorAdapter<T>
where
    T: DescriptorIntoAsync,
{
    fn as_raw_fd(&self) -> RawFd {
        self.0.as_raw_descriptor()
    }
}
impl<T> IntoAsync for DescriptorAdapter<T> where T: DescriptorIntoAsync {}