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use crate::errno::Errno;
use crate::{Result,unistd};
use std::os::unix::io::{FromRawFd, OwnedFd, AsRawFd, AsFd, RawFd, BorrowedFd};
libc_bitflags! {
pub struct EfdFlags: libc::c_int {
EFD_CLOEXEC; // Since Linux 2.6.27/FreeBSD 13.0
EFD_NONBLOCK; // Since Linux 2.6.27/FreeBSD 13.0
EFD_SEMAPHORE; // Since Linux 2.6.30/FreeBSD 13.0
}
}
#[deprecated(since = "0.28.0", note = "Use EventFd::from_value_and_flags() instead")]
pub fn eventfd(initval: libc::c_uint, flags: EfdFlags) -> Result<OwnedFd> {
let res = unsafe { libc::eventfd(initval, flags.bits()) };
Errno::result(res).map(|r| unsafe { OwnedFd::from_raw_fd(r) })
}
#[derive(Debug)]
#[repr(transparent)]
pub struct EventFd(OwnedFd);
impl EventFd {
/// [`EventFd::from_value_and_flags`] with `init_val = 0` and `flags = EfdFlags::empty()`.
pub fn new() -> Result<Self> {
Self::from_value_and_flags(0, EfdFlags::empty())
}
/// Constructs [`EventFd`] with the given `init_val` and `flags`.
///
/// Wrapper around [`libc::eventfd`].
pub fn from_value_and_flags(init_val: u32, flags: EfdFlags) -> Result<Self> {
let res = unsafe { libc::eventfd(init_val, flags.bits()) };
Errno::result(res).map(|r| Self(unsafe { OwnedFd::from_raw_fd(r) }))
}
/// [`EventFd::from_value_and_flags`] with `init_val = 0` and given `flags`.
pub fn from_flags(flags: EfdFlags) -> Result<Self> {
Self::from_value_and_flags(0, flags)
}
/// [`EventFd::from_value_and_flags`] with given `init_val` and `flags = EfdFlags::empty()`.
pub fn from_value(init_val: u32) -> Result<Self> {
Self::from_value_and_flags(init_val, EfdFlags::empty())
}
/// Arms `self`, a following call to `poll`, `select` or `epoll` will return immediately.
///
/// [`EventFd::write`] with `1`.
pub fn arm(&self) -> Result<usize> {
self.write(1)
}
/// Defuses `self`, a following call to `poll`, `select` or `epoll` will block.
///
/// [`EventFd::write`] with `0`.
pub fn defuse(&self) -> Result<usize> {
self.write(0)
}
/// Enqueues `value` triggers.
///
/// The next `value` calls to `poll`, `select` or `epoll` will return immediately.
///
/// [`EventFd::write`] with `value`.
pub fn write(&self, value: u64) -> Result<usize> {
unistd::write(&self.0,&value.to_ne_bytes())
}
// Reads the value from the file descriptor.
pub fn read(&self) -> Result<u64> {
let mut arr = [0; std::mem::size_of::<u64>()];
unistd::read(self.0.as_raw_fd(),&mut arr)?;
Ok(u64::from_ne_bytes(arr))
}
}
impl AsFd for EventFd {
fn as_fd(&self) -> BorrowedFd {
self.0.as_fd()
}
}
impl AsRawFd for EventFd {
fn as_raw_fd(&self) -> RawFd {
self.0.as_raw_fd()
}
}
impl From<EventFd> for OwnedFd {
fn from(x: EventFd) -> OwnedFd {
x.0
}
}