1 files changed, 92 insertions, 0 deletions
diff --git a/third_party/rust/miow/src/overlapped.rs b/third_party/rust/miow/src/overlapped.rs
new file mode 100644
index 0000000000..abe2d37cbb
--- /dev/null
+++ b/third_party/rust/miow/src/overlapped.rs
@@ -0,0 +1,92 @@
+use std::fmt;
+use std::io;
+use std::mem;
+use std::ptr;
+
+use winapi::shared::ntdef::{HANDLE, NULL};
+use winapi::um::minwinbase::*;
+use winapi::um::synchapi::*;
+
+/// A wrapper around `OVERLAPPED` to provide "rustic" accessors and
+/// initializers.
+pub struct Overlapped(OVERLAPPED);
+
+impl fmt::Debug for Overlapped {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        write!(f, "OVERLAPPED")
+    }
+}
+
+unsafe impl Send for Overlapped {}
+unsafe impl Sync for Overlapped {}
+
+impl Overlapped {
+    /// Creates a new zeroed out instance of an overlapped I/O tracking state.
+    ///
+    /// This is suitable for passing to methods which will then later get
+    /// notified via an I/O Completion Port.
+    pub fn zero() -> Overlapped {
+        Overlapped(unsafe { mem::zeroed() })
+    }
+
+    /// Creates a new `Overlapped` with an initialized non-null `hEvent`.  The caller is
+    /// responsible for calling `CloseHandle` on the `hEvent` field of the returned
+    /// `Overlapped`.  The event is created with `bManualReset` set to `FALSE`, meaning after a
+    /// single thread waits on the event, it will be reset.
+    pub fn initialize_with_autoreset_event() -> io::Result<Overlapped> {
+        let event = unsafe { CreateEventW(ptr::null_mut(), 0i32, 0i32, ptr::null()) };
+        if event == NULL {
+            return Err(io::Error::last_os_error());
+        }
+        let mut overlapped = Self::zero();
+        overlapped.set_event(event);
+        Ok(overlapped)
+    }
+
+    /// Creates a new `Overlapped` function pointer from the underlying
+    /// `OVERLAPPED`, wrapping in the "rusty" wrapper for working with
+    /// accessors.
+    ///
+    /// # Unsafety
+    ///
+    /// This function doesn't validate `ptr` nor the lifetime of the returned
+    /// pointer at all, it's recommended to use this method with extreme
+    /// caution.
+    pub unsafe fn from_raw<'a>(ptr: *mut OVERLAPPED) -> &'a mut Overlapped {
+        &mut *(ptr as *mut Overlapped)
+    }
+
+    /// Gain access to the raw underlying data
+    pub fn raw(&self) -> *mut OVERLAPPED {
+        &self.0 as *const _ as *mut _
+    }
+
+    /// Sets the offset inside this overlapped structure.
+    ///
+    /// Note that for I/O operations in general this only has meaning for I/O
+    /// handles that are on a seeking device that supports the concept of an
+    /// offset.
+    pub fn set_offset(&mut self, offset: u64) {
+        let s = unsafe { self.0.u.s_mut() };
+        s.Offset = offset as u32;
+        s.OffsetHigh = (offset >> 32) as u32;
+    }
+
+    /// Reads the offset inside this overlapped structure.
+    pub fn offset(&self) -> u64 {
+        let s = unsafe { self.0.u.s() };
+        (s.Offset as u64) | ((s.OffsetHigh as u64) << 32)
+    }
+
+    /// Sets the `hEvent` field of this structure.
+    ///
+    /// The event specified can be null.
+    pub fn set_event(&mut self, event: HANDLE) {
+        self.0.hEvent = event;
+    }
+
+    /// Reads the `hEvent` field of this structure, may return null.
+    pub fn event(&self) -> HANDLE {
+        self.0.hEvent
+    }
+}