1 files changed, 179 insertions, 0 deletions
diff --git a/third_party/rust/mio/src/interest.rs b/third_party/rust/mio/src/interest.rs
new file mode 100644
index 0000000000..0aa0bda895
--- /dev/null
+++ b/third_party/rust/mio/src/interest.rs
@@ -0,0 +1,179 @@
+use std::num::NonZeroU8;
+use std::{fmt, ops};
+
+/// Interest used in registering.
+///
+/// Interest are used in [registering] [`event::Source`]s with [`Poll`], they
+/// indicate what readiness should be monitored for. For example if a socket is
+/// registered with [readable] interests and the socket becomes writable, no
+/// event will be returned from a call to [`poll`].
+///
+/// [registering]: struct.Registry.html#method.register
+/// [`event::Source`]: ./event/trait.Source.html
+/// [`Poll`]: struct.Poll.html
+/// [readable]: struct.Interest.html#associatedconstant.READABLE
+/// [`poll`]: struct.Poll.html#method.poll
+#[derive(Copy, PartialEq, Eq, Clone, PartialOrd, Ord)]
+pub struct Interest(NonZeroU8);
+
+// These must be unique.
+const READABLE: u8 = 0b0001;
+const WRITABLE: u8 = 0b0010;
+// The following are not available on all platforms.
+#[cfg_attr(
+    not(any(
+        target_os = "dragonfly",
+        target_os = "freebsd",
+        target_os = "ios",
+        target_os = "macos"
+    )),
+    allow(dead_code)
+)]
+const AIO: u8 = 0b0100;
+#[cfg_attr(not(target_os = "freebsd"), allow(dead_code))]
+const LIO: u8 = 0b1000;
+
+impl Interest {
+    /// Returns a `Interest` set representing readable interests.
+    pub const READABLE: Interest = Interest(unsafe { NonZeroU8::new_unchecked(READABLE) });
+
+    /// Returns a `Interest` set representing writable interests.
+    pub const WRITABLE: Interest = Interest(unsafe { NonZeroU8::new_unchecked(WRITABLE) });
+
+    /// Returns a `Interest` set representing AIO completion interests.
+    #[cfg(any(
+        target_os = "dragonfly",
+        target_os = "freebsd",
+        target_os = "ios",
+        target_os = "macos"
+    ))]
+    pub const AIO: Interest = Interest(unsafe { NonZeroU8::new_unchecked(AIO) });
+
+    /// Returns a `Interest` set representing LIO completion interests.
+    #[cfg(target_os = "freebsd")]
+    pub const LIO: Interest = Interest(unsafe { NonZeroU8::new_unchecked(LIO) });
+
+    /// Add together two `Interest`.
+    ///
+    /// This does the same thing as the `BitOr` implementation, but is a
+    /// constant function.
+    ///
+    /// ```
+    /// use mio::Interest;
+    ///
+    /// const INTERESTS: Interest = Interest::READABLE.add(Interest::WRITABLE);
+    /// # fn silent_dead_code_warning(_: Interest) { }
+    /// # silent_dead_code_warning(INTERESTS)
+    /// ```
+    #[allow(clippy::should_implement_trait)]
+    pub const fn add(self, other: Interest) -> Interest {
+        Interest(unsafe { NonZeroU8::new_unchecked(self.0.get() | other.0.get()) })
+    }
+
+    /// Removes `other` `Interest` from `self`.
+    ///
+    /// Returns `None` if the set would be empty after removing `other`.
+    ///
+    /// ```
+    /// use mio::Interest;
+    ///
+    /// const RW_INTERESTS: Interest = Interest::READABLE.add(Interest::WRITABLE);
+    ///
+    /// // As long a one interest remain this will return `Some`.
+    /// let w_interest = RW_INTERESTS.remove(Interest::READABLE).unwrap();
+    /// assert!(!w_interest.is_readable());
+    /// assert!(w_interest.is_writable());
+    ///
+    /// // Removing all interests from the set will return `None`.
+    /// assert_eq!(w_interest.remove(Interest::WRITABLE), None);
+    ///
+    /// // Its also possible to remove multiple interests at once.
+    /// assert_eq!(RW_INTERESTS.remove(RW_INTERESTS), None);
+    /// ```
+    pub fn remove(self, other: Interest) -> Option<Interest> {
+        NonZeroU8::new(self.0.get() & !other.0.get()).map(Interest)
+    }
+
+    /// Returns true if the value includes readable readiness.
+    pub const fn is_readable(self) -> bool {
+        (self.0.get() & READABLE) != 0
+    }
+
+    /// Returns true if the value includes writable readiness.
+    pub const fn is_writable(self) -> bool {
+        (self.0.get() & WRITABLE) != 0
+    }
+
+    /// Returns true if `Interest` contains AIO readiness
+    pub const fn is_aio(self) -> bool {
+        (self.0.get() & AIO) != 0
+    }
+
+    /// Returns true if `Interest` contains LIO readiness
+    pub const fn is_lio(self) -> bool {
+        (self.0.get() & LIO) != 0
+    }
+}
+
+impl ops::BitOr for Interest {
+    type Output = Self;
+
+    #[inline]
+    fn bitor(self, other: Self) -> Self {
+        self.add(other)
+    }
+}
+
+impl ops::BitOrAssign for Interest {
+    #[inline]
+    fn bitor_assign(&mut self, other: Self) {
+        self.0 = (*self | other).0;
+    }
+}
+
+impl fmt::Debug for Interest {
+    fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result {
+        let mut one = false;
+        if self.is_readable() {
+            if one {
+                write!(fmt, " | ")?
+            }
+            write!(fmt, "READABLE")?;
+            one = true
+        }
+        if self.is_writable() {
+            if one {
+                write!(fmt, " | ")?
+            }
+            write!(fmt, "WRITABLE")?;
+            one = true
+        }
+        #[cfg(any(
+            target_os = "dragonfly",
+            target_os = "freebsd",
+            target_os = "ios",
+            target_os = "macos"
+        ))]
+        {
+            if self.is_aio() {
+                if one {
+                    write!(fmt, " | ")?
+                }
+                write!(fmt, "AIO")?;
+                one = true
+            }
+        }
+        #[cfg(any(target_os = "freebsd"))]
+        {
+            if self.is_lio() {
+                if one {
+                    write!(fmt, " | ")?
+                }
+                write!(fmt, "LIO")?;
+                one = true
+            }
+        }
+        debug_assert!(one, "printing empty interests");
+        Ok(())
+    }
+}