1 files changed, 78 insertions, 0 deletions
diff --git a/third_party/rust/mio/src/sys/fuchsia/handles.rs b/third_party/rust/mio/src/sys/fuchsia/handles.rs
new file mode 100644
index 0000000000..ae6f07f6d9
--- /dev/null
+++ b/third_party/rust/mio/src/sys/fuchsia/handles.rs
@@ -0,0 +1,78 @@
+use {io, poll, Evented, Ready, Poll, PollOpt, Token};
+use zircon_sys::zx_handle_t;
+use std::sync::Mutex;
+
+/// Wrapper for registering a `HandleBase` type with mio.
+#[derive(Debug)]
+pub struct EventedHandle {
+    /// The handle to be registered.
+    handle: zx_handle_t,
+
+    /// The current `Token` with which the handle is registered with mio.
+    token: Mutex<Option<Token>>,
+}
+
+impl EventedHandle {
+    /// Create a new `EventedHandle` which can be registered with mio
+    /// in order to receive event notifications.
+    ///
+    /// The underlying handle must not be dropped while the
+    /// `EventedHandle` still exists.
+    pub unsafe fn new(handle: zx_handle_t) -> Self {
+        EventedHandle {
+            handle: handle,
+            token: Mutex::new(None),
+        }
+    }
+
+    /// Get the underlying handle being registered.
+    pub fn get_handle(&self) -> zx_handle_t {
+        self.handle
+    }
+}
+
+impl Evented for EventedHandle {
+    fn register(&self,
+                poll: &Poll,
+                token: Token,
+                interest: Ready,
+                opts: PollOpt) -> io::Result<()>
+    {
+        let mut this_token = self.token.lock().unwrap();
+        {
+            poll::selector(poll).register_handle(self.handle, token, interest, opts)?;
+            *this_token = Some(token);
+        }
+        Ok(())
+    }
+
+    fn reregister(&self,
+        poll: &Poll,
+        token: Token,
+        interest: Ready,
+        opts: PollOpt) -> io::Result<()>
+    {
+        let mut this_token = self.token.lock().unwrap();
+        {
+            poll::selector(poll).deregister_handle(self.handle, token)?;
+            *this_token = None;
+            poll::selector(poll).register_handle(self.handle, token, interest, opts)?;
+            *this_token = Some(token);
+        }
+        Ok(())
+    }
+
+    fn deregister(&self, poll: &Poll) -> io::Result<()> {
+        let mut this_token = self.token.lock().unwrap();
+        let token = if let Some(token) = *this_token { token } else {
+            return Err(io::Error::new(
+                io::ErrorKind::NotFound,
+                "Attempted to deregister an unregistered handle."))
+        };
+        {
+            poll::selector(poll).deregister_handle(self.handle, token)?;
+            *this_token = None;
+        }
+        Ok(())
+    }
+}