// Copyright (c) 2023 Huawei Device Co., Ltd.
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

use std::io;

use crate::sys::WakerInner;
use crate::{Poll, Token};

/// Waker allows cross-thread waking of Poll.
#[derive(Debug)]
pub struct Waker {
    inner: WakerInner,
}

impl Waker {
    /// Creates a new Waker
    pub fn new(poll: &Poll, token: Token) -> io::Result<Self> {
        WakerInner::new(poll.selector(), token).map(|inner| Waker { inner })
    }
    /// Wakes up the [`Poll`] associated with this `Waker`
    pub fn wake(&self) -> io::Result<()> {
        self.inner.wake()
    }
}

#[cfg(test)]
mod test {
    /// UT cases for debug info of waker
    ///
    /// # Brief
    /// 1. Create a Waker
    /// 2. Check its fmt debug info
    #[test]
    #[cfg(target_os = "linux")]
    fn ut_waker_debug_info() {
        use crate::{Poll, Token, Waker};

        let poll = Poll::new().unwrap();
        let waker = Waker::new(&poll, Token::from_usize(0)).unwrap();
        let fmt = format!("{:?}", waker);
        assert!(fmt.contains("fd:"));
        assert!(fmt.contains("read:"));
        assert!(fmt.contains("write:"));
    }
}