Import mio-0.7.3

Test: None
Change-Id: I7df903972aaf06adb1ecb20a63793fcf128edb8f

1 files changed, 174 insertions, 0 deletions

diff --git a/src/sys/unix/waker.rs b/src/sys/unix/waker.rs
new file mode 100644
index 0000000..1305bd6
--- /dev/null
+++ b/src/sys/unix/waker.rs
@@ -0,0 +1,174 @@
+#[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<()> {
+            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;