| #[cfg(any(target_os = "linux", target_os = "android"))] |
| mod eventfd { |
| use crate::sys::Selector; |
| use crate::{Interest, Token}; |
| |
| use std::fs::File; |
| use std::io::{self, Read, Write}; |
| use std::os::unix::io::FromRawFd; |
| |
| /// Waker backed by `eventfd`. |
| /// |
| /// `eventfd` is effectively an 64 bit counter. All writes must be of 8 |
| /// bytes (64 bits) and are converted (native endian) into an 64 bit |
| /// unsigned integer and added to the count. Reads must also be 8 bytes and |
| /// reset the count to 0, returning the count. |
| #[derive(Debug)] |
| pub struct Waker { |
| fd: File, |
| } |
| |
| impl Waker { |
| pub fn new(selector: &Selector, token: Token) -> io::Result<Waker> { |
| syscall!(eventfd(0, libc::EFD_CLOEXEC | libc::EFD_NONBLOCK)).and_then(|fd| { |
| // Turn the file descriptor into a file first so we're ensured |
| // it's closed when dropped, e.g. when register below fails. |
| let file = unsafe { File::from_raw_fd(fd) }; |
| selector |
| .register(fd, token, Interest::READABLE) |
| .map(|()| Waker { fd: file }) |
| }) |
| } |
| |
| pub fn wake(&self) -> io::Result<()> { |
| let buf: [u8; 8] = 1u64.to_ne_bytes(); |
| match (&self.fd).write(&buf) { |
| Ok(_) => Ok(()), |
| Err(ref err) if err.kind() == io::ErrorKind::WouldBlock => { |
| // Writing only blocks if the counter is going to overflow. |
| // So we'll reset the counter to 0 and wake it again. |
| self.reset()?; |
| self.wake() |
| } |
| Err(err) => Err(err), |
| } |
| } |
| |
| /// Reset the eventfd object, only need to call this if `wake` fails. |
| fn reset(&self) -> io::Result<()> { |
| let mut buf: [u8; 8] = 0u64.to_ne_bytes(); |
| match (&self.fd).read(&mut buf) { |
| Ok(_) => Ok(()), |
| // If the `Waker` hasn't been awoken yet this will return a |
| // `WouldBlock` error which we can safely ignore. |
| Err(ref err) if err.kind() == io::ErrorKind::WouldBlock => Ok(()), |
| Err(err) => Err(err), |
| } |
| } |
| } |
| } |
| |
| #[cfg(any(target_os = "linux", target_os = "android"))] |
| pub use self::eventfd::Waker; |
| |
| #[cfg(any(target_os = "freebsd", target_os = "ios", target_os = "macos"))] |
| mod kqueue { |
| use crate::sys::Selector; |
| use crate::Token; |
| |
| use std::io; |
| |
| /// Waker backed by kqueue user space notifications (`EVFILT_USER`). |
| /// |
| /// The implementation is fairly simple, first the kqueue must be setup to |
| /// receive waker events this done by calling `Selector.setup_waker`. Next |
| /// we need access to kqueue, thus we need to duplicate the file descriptor. |
| /// Now waking is as simple as adding an event to the kqueue. |
| #[derive(Debug)] |
| pub struct Waker { |
| selector: Selector, |
| token: Token, |
| } |
| |
| impl Waker { |
| pub fn new(selector: &Selector, token: Token) -> io::Result<Waker> { |
| selector.try_clone().and_then(|selector| { |
| selector |
| .setup_waker(token) |
| .map(|()| Waker { selector, token }) |
| }) |
| } |
| |
| pub fn wake(&self) -> io::Result<()> { |
| self.selector.wake(self.token) |
| } |
| } |
| } |
| |
| #[cfg(any(target_os = "freebsd", target_os = "ios", target_os = "macos"))] |
| pub use self::kqueue::Waker; |
| |
| #[cfg(any( |
| target_os = "dragonfly", |
| target_os = "illumos", |
| target_os = "netbsd", |
| target_os = "openbsd", |
| target_os = "solaris" |
| ))] |
| mod pipe { |
| use crate::sys::unix::Selector; |
| use crate::{Interest, Token}; |
| |
| use std::fs::File; |
| use std::io::{self, Read, Write}; |
| use std::os::unix::io::FromRawFd; |
| |
| /// Waker backed by a unix pipe. |
| /// |
| /// Waker controls both the sending and receiving ends and empties the pipe |
| /// if writing to it (waking) fails. |
| #[derive(Debug)] |
| pub struct Waker { |
| sender: File, |
| receiver: File, |
| } |
| |
| impl Waker { |
| pub fn new(selector: &Selector, token: Token) -> io::Result<Waker> { |
| let mut fds = [-1; 2]; |
| syscall!(pipe2(fds.as_mut_ptr(), libc::O_NONBLOCK | libc::O_CLOEXEC))?; |
| // Turn the file descriptors into files first so we're ensured |
| // they're closed when dropped, e.g. when register below fails. |
| let sender = unsafe { File::from_raw_fd(fds[1]) }; |
| let receiver = unsafe { File::from_raw_fd(fds[0]) }; |
| selector |
| .register(fds[0], token, Interest::READABLE) |
| .map(|()| Waker { sender, receiver }) |
| } |
| |
| pub fn wake(&self) -> io::Result<()> { |
| // The epoll emulation on some illumos systems currently requires |
| // the pipe buffer to be completely empty for an edge-triggered |
| // wakeup on the pipe read side. |
| #[cfg(target_os = "illumos")] |
| self.empty(); |
| |
| match (&self.sender).write(&[1]) { |
| Ok(_) => Ok(()), |
| Err(ref err) if err.kind() == io::ErrorKind::WouldBlock => { |
| // The reading end is full so we'll empty the buffer and try |
| // again. |
| self.empty(); |
| self.wake() |
| } |
| Err(ref err) if err.kind() == io::ErrorKind::Interrupted => self.wake(), |
| Err(err) => Err(err), |
| } |
| } |
| |
| /// Empty the pipe's buffer, only need to call this if `wake` fails. |
| /// This ignores any errors. |
| fn empty(&self) { |
| let mut buf = [0; 4096]; |
| loop { |
| match (&self.receiver).read(&mut buf) { |
| Ok(n) if n > 0 => continue, |
| _ => return, |
| } |
| } |
| } |
| } |
| } |
| |
| #[cfg(any( |
| target_os = "dragonfly", |
| target_os = "illumos", |
| target_os = "netbsd", |
| target_os = "openbsd", |
| target_os = "solaris" |
| ))] |
| pub use self::pipe::Waker; |