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#![allow(clippy::undocumented_unsafe_blocks)] // Remove me if you dare.
use std::{
io,
os::windows::io::{AsRawHandle, FromRawHandle, OwnedHandle, RawHandle},
ptr,
};
use windows_sys::Win32::{
Foundation::{DUPLICATE_SAME_ACCESS, DuplicateHandle},
System::Threading::{CreateEventW, GetCurrentProcess, SetEvent},
};
/// Windows event object
pub struct Event(OwnedHandle);
unsafe impl Send for Event {}
unsafe impl Sync for Event {}
impl Event {
/// Create a new event object using `CreateEventW`
pub fn new(manual_reset: bool, initial_state: bool) -> io::Result<Self> {
let event = unsafe {
CreateEventW(
ptr::null_mut(),
i32::from(manual_reset),
i32::from(initial_state),
ptr::null(),
)
};
if event.is_null() {
return Err(io::Error::last_os_error());
}
// SAFETY: `event` is a valid handle since `CreateEventW` succeeded
Ok(Self(unsafe { OwnedHandle::from_raw_handle(event) }))
}
/// Signal the event object
pub fn set(&self) -> io::Result<()> {
// SAFETY: `self.0` is a valid handle
if unsafe { SetEvent(self.0.as_raw_handle()) } == 0 {
return Err(io::Error::last_os_error());
}
Ok(())
}
/// Duplicate the event object with `DuplicateHandle()`
pub fn duplicate(&self) -> io::Result<Event> {
let mut new_event = ptr::null_mut();
let status = unsafe {
DuplicateHandle(
GetCurrentProcess(),
self.0.as_raw_handle(),
GetCurrentProcess(),
&mut new_event,
0,
0,
DUPLICATE_SAME_ACCESS,
)
};
if status == 0 {
return Err(io::Error::last_os_error());
}
// SAFETY: `new_event` is a valid handle since `DuplicateHandle` succeeded
Ok(Event(unsafe { OwnedHandle::from_raw_handle(new_event) }))
}
}
impl AsRawHandle for Event {
fn as_raw_handle(&self) -> RawHandle {
self.0.as_raw_handle()
}
}
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