From b5dde3852ad5db1b6e532ae8dd82cedc1deb95e2 Mon Sep 17 00:00:00 2001
From: Jonathan <jonathanwoollettlight@gmail.com>
Date: Tue, 14 Feb 2023 21:24:05 +0000
Subject: [PATCH] feat: EventFd type

---
 CHANGELOG.md       |  2 ++
 src/sys/epoll.rs   |  6 ++---
 src/sys/eventfd.rs | 65 ++++++++++++++++++++++++++++++++++++++++++++--
 3 files changed, 68 insertions(+), 5 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index e8bde843f1..4663d29422 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -16,6 +16,8 @@ This project adheres to [Semantic Versioning](https://semver.org/).
 - Added `mq_timedreceive` to `::nix::mqueue`.
   ([#1966])(https://github.com/nix-rust/nix/pull/1966)
 - Added `LocalPeerPid` to `nix::sys::socket::sockopt` for macOS. ([#1967](https://github.com/nix-rust/nix/pull/1967))
+  - Added `EventFd` type.
+  ([#1945](https://github.com/nix-rust/nix/pull/1945))
 
 ### Changed
 
diff --git a/src/sys/epoll.rs b/src/sys/epoll.rs
index 36f9c17d0e..e7f9f89a0b 100644
--- a/src/sys/epoll.rs
+++ b/src/sys/epoll.rs
@@ -71,7 +71,7 @@ impl EpollEvent {
 
 /// A safe wrapper around [`epoll`](https://man7.org/linux/man-pages/man7/epoll.7.html).
 /// ```
-/// # use nix::sys::{epoll::{Epoll, EpollEvent, EpollFlags, EpollCreateFlags}, eventfd::{eventfd, EfdFlags}};
+/// # use nix::sys::{epoll::{Epoll, EpollEvent, EpollFlags, EpollCreateFlags}, eventfd::{EventFd, EfdFlags}};
 /// # use nix::unistd::write;
 /// # use std::os::unix::io::{OwnedFd, FromRawFd, AsRawFd, AsFd};
 /// # use std::time::{Instant, Duration};
@@ -83,11 +83,11 @@ impl EpollEvent {
 /// let epoll = Epoll::new(EpollCreateFlags::empty())?;
 ///
 /// // Create eventfd & Add event
-/// let eventfd = eventfd(0, EfdFlags::empty())?;
+/// let eventfd = EventFd::new()?;
 /// epoll.add(&eventfd, EpollEvent::new(EpollFlags::EPOLLIN,DATA))?;
 ///
 /// // Arm eventfd & Time wait
-/// write(eventfd.as_raw_fd(), &1u64.to_ne_bytes())?;
+/// eventfd.arm()?;
 /// let now = Instant::now();
 ///
 /// // Wait on event
diff --git a/src/sys/eventfd.rs b/src/sys/eventfd.rs
index f1723519cf..bf3a96242a 100644
--- a/src/sys/eventfd.rs
+++ b/src/sys/eventfd.rs
@@ -1,6 +1,6 @@
 use crate::errno::Errno;
-use crate::Result;
-use std::os::unix::io::{FromRawFd, OwnedFd};
+use crate::{Result,unistd};
+use std::os::unix::io::{FromRawFd, OwnedFd, AsRawFd, AsFd, RawFd, BorrowedFd};
 
 libc_bitflags! {
     pub struct EfdFlags: libc::c_int {
@@ -10,8 +10,69 @@ libc_bitflags! {
     }
 }
 
+#[deprecated(since = "0.27.0", 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)]
+pub struct EventFd(pub 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> {
+        unistd::write(self.0.as_raw_fd(),&1u64.to_ne_bytes())
+    }
+    /// Defuses `self`, a following call to `poll`, `select` or `epoll` will block.
+    /// 
+    /// [`EventFd::write`] with `0`.
+    pub fn defuse(&self) -> Result<usize> {
+        unistd::write(self.0.as_raw_fd(),&0u64.to_ne_bytes())
+    }
+    /// 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.as_raw_fd(),&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()
+    }
+}
\ No newline at end of file