user0/rust
1
0
Fork 0
Code Issues Pull requests Projects Releases Packages Wiki Activity Actions

Add Waker::wake_by_ref and make Waker::wake consume the Waker

Browse source
This commit is contained in:
Taylor Cramer 2019-04-05 11:46:30 -07:00
parent 3750348daf
commit 01be78d69f
4 changed files with 73 additions and 19 deletions
Download patch file Download diff file Expand all files Collapse all files

52
src/libcore/task/wake.rs
View file

@ -72,10 +72,18 @@ pub struct RawWakerVTable {
/// This function will be called when `wake` is called on the [`Waker`].
/// It must wake up the task associated with this [`RawWaker`].
///
/// The implemention of this function must not consume the provided data
/// pointer.
/// The implementation of this function must make sure to release any
/// resources that are associated with this instance of a [`RawWaker`] and
/// associated task.
wake: unsafe fn(*const ()),
/// This function will be called when `wake_by_ref` is called on the [`Waker`].
/// It must wake up the task associated with this [`RawWaker`].
///
/// This function is similar to `wake`, but must not consume the provided data
/// pointer.
wake_by_ref: unsafe fn(*const ()),
/// This function gets called when a [`RawWaker`] gets dropped.
///
/// The implementation of this function must make sure to release any
@ -85,8 +93,8 @@ pub struct RawWakerVTable {
}
impl RawWakerVTable {
/// Creates a new `RawWakerVTable` from the provided `clone`, `wake`, and
/// `drop` functions.
/// Creates a new `RawWakerVTable` from the provided `clone`, `wake`,
/// `wake_by_ref`, and `drop` functions.
///
/// # `clone`
///
@ -103,7 +111,16 @@ impl RawWakerVTable {
/// This function will be called when `wake` is called on the [`Waker`].
/// It must wake up the task associated with this [`RawWaker`].
///
/// The implemention of this function must not consume the provided data
/// The implementation of this function must make sure to release any
/// resources that are associated with this instance of a [`RawWaker`] and
/// associated task.
///
/// # `wake_by_ref`
///
/// This function will be called when `wake_by_ref` is called on the [`Waker`].
/// It must wake up the task associated with this [`RawWaker`].
///
/// This function is similar to `wake`, but must not consume the provided data
/// pointer.
///
/// # `drop`
@ -120,11 +137,13 @@ impl RawWakerVTable {
pub const fn new(
clone: unsafe fn(*const ()) -> RawWaker,
wake: unsafe fn(*const ()),
wake_by_ref: unsafe fn(*const ()),
drop: unsafe fn(*const ()),
) -> Self {
Self {
clone,
wake,
wake_by_ref,
drop,
}
}
@ -187,14 +206,33 @@ unsafe impl Sync for Waker {}
impl Waker {
/// Wake up the task associated with this `Waker`.
#[inline]
pub fn wake(&self) {
pub fn wake(self) {
// The actual wakeup call is delegated through a virtual function call
// to the implementation which is defined by the executor.
let wake = self.waker.vtable.wake;
let data = self.waker.data;
// Don't call `drop` -- the waker will be consumed by `wake`.
crate::mem::forget(self);
// SAFETY: This is safe because `Waker::new_unchecked` is the only way
// to initialize `wake` and `data` requiring the user to acknowledge
// that the contract of `RawWaker` is upheld.
unsafe { (self.waker.vtable.wake)(self.waker.data) }
unsafe { (wake)(data) };
}
/// Wake up the task associated with this `Waker` without consuming the `Waker`.
///
/// This is similar to `wake`, but may be slightly less efficient in the case
/// where an owned `Waker` is available. This method should be preferred to
/// calling `waker.clone().wake()`.
#[inline]
pub fn wake_by_ref(&self) {
// The actual wakeup call is delegated through a virtual function call
// to the implementation which is defined by the executor.
// SAFETY: see `wake`
unsafe { (self.waker.vtable.wake_by_ref)(self.waker.data) }
}
/// Returns `true` if this `Waker` and another `Waker` have awoken the same task.