Rollup merge of #129919 - kevinmehall:waker-getters, r=dtolnay

Stabilize `waker_getters`

Tracking issue: #96992

FCP completed on the tracking issue a while ago. It's not clear whether the libs-api team wanted the `RawWaker` methods moved to `Waker` or went back to the current API after further discussion. `@Amanieu` [wrote "This is just waiting for someone to submit a stabilization PR."](https://github.com/rust-lang/rust/issues/96992#issuecomment-2213685218) so I'm doing just that in hopes of nudging this along.

Edit: Moved the `data` and `vtable` methods from `RawWaker` to `Waker` and added `Waker::new` per https://github.com/rust-lang/rust/issues/96992#issuecomment-1941998046

```rs
impl Waker {
  pub const unsafe fn new(data: *const (), vtable: &'static RawWakerVTable) -> Self;
  pub fn data(&self) -> *const ();
  pub fn vtable(&self) -> &'static RawWakerVTable;
}
```

Closes #96992

library/core/src/task/wake.rs

@@ -60,22 +60,6 @@ impl RawWaker {
         RawWaker { data, vtable }
     }
 
-    /// Gets the `data` pointer used to create this `RawWaker`.
-    #[inline]
-    #[must_use]
-    #[unstable(feature = "waker_getters", issue = "96992")]
-    pub fn data(&self) -> *const () {
-        self.data
-    }
-
-    /// Gets the `vtable` pointer used to create this `RawWaker`.
-    #[inline]
-    #[must_use]
-    #[unstable(feature = "waker_getters", issue = "96992")]
-    pub fn vtable(&self) -> &'static RawWakerVTable {
-        self.vtable
-    }
-
     #[unstable(feature = "noop_waker", issue = "98286")]
     const NOOP: RawWaker = {
         const VTABLE: RawWakerVTable = RawWakerVTable::new(
@@ -509,6 +493,37 @@ impl Waker {
         a_data == b_data && ptr::eq(a_vtable, b_vtable)
     }
 
+    /// Creates a new `Waker` from the provided `data` pointer and `vtable`.
+    ///
+    /// The `data` pointer can be used to store arbitrary data as required
+    /// by the executor. This could be e.g. a type-erased pointer to an `Arc`
+    /// that is associated with the task.
+    /// The value of this pointer will get passed to all functions that are part
+    /// of the `vtable` as the first parameter.
+    ///
+    /// It is important to consider that the `data` pointer must point to a
+    /// thread safe type such as an `Arc`.
+    ///
+    /// The `vtable` customizes the behavior of a `Waker`. For each operation
+    /// on the `Waker`, the associated function in the `vtable` will be called.
+    ///
+    /// # Safety
+    ///
+    /// The behavior of the returned `Waker` is undefined if the contract defined
+    /// in [`RawWakerVTable`]'s documentation is not upheld.
+    ///
+    /// (Authors wishing to avoid unsafe code may implement the [`Wake`] trait instead, at the
+    /// cost of a required heap allocation.)
+    ///
+    /// [`Wake`]: ../../alloc/task/trait.Wake.html
+    #[inline]
+    #[must_use]
+    #[stable(feature = "waker_getters", since = "CURRENT_RUSTC_VERSION")]
+    #[rustc_const_stable(feature = "waker_getters", since = "CURRENT_RUSTC_VERSION")]
+    pub const unsafe fn new(data: *const (), vtable: &'static RawWakerVTable) -> Self {
+        Waker { waker: RawWaker { data, vtable } }
+    }
+
     /// Creates a new `Waker` from [`RawWaker`].
     ///
     /// # Safety
@@ -565,12 +580,20 @@ impl Waker {
         WAKER
     }
 
-    /// Gets a reference to the underlying [`RawWaker`].
+    /// Gets the `data` pointer used to create this `Waker`.
     #[inline]
     #[must_use]
-    #[unstable(feature = "waker_getters", issue = "96992")]
-    pub fn as_raw(&self) -> &RawWaker {
-        &self.waker
+    #[stable(feature = "waker_getters", since = "CURRENT_RUSTC_VERSION")]
+    pub fn data(&self) -> *const () {
+        self.waker.data
+    }
+
+    /// Gets the `vtable` pointer used to create this `Waker`.
+    #[inline]
+    #[must_use]
+    #[stable(feature = "waker_getters", since = "CURRENT_RUSTC_VERSION")]
+    pub fn vtable(&self) -> &'static RawWakerVTable {
+        self.waker.vtable
     }
 }
 
@@ -778,6 +801,30 @@ impl LocalWaker {
         a_data == b_data && ptr::eq(a_vtable, b_vtable)
     }
 
+    /// Creates a new `LocalWaker` from the provided `data` pointer and `vtable`.
+    ///
+    /// The `data` pointer can be used to store arbitrary data as required
+    /// by the executor. This could be e.g. a type-erased pointer to an `Arc`
+    /// that is associated with the task.
+    /// The value of this pointer will get passed to all functions that are part
+    /// of the `vtable` as the first parameter.
+    ///
+    /// The `vtable` customizes the behavior of a `LocalWaker`. For each
+    /// operation on the `LocalWaker`, the associated function in the `vtable`
+    /// will be called.
+    ///
+    /// # Safety
+    ///
+    /// The behavior of the returned `Waker` is undefined if the contract defined
+    /// in [`RawWakerVTable`]'s documentation is not upheld.
+    ///
+    #[inline]
+    #[must_use]
+    #[unstable(feature = "local_waker", issue = "118959")]
+    pub const unsafe fn new(data: *const (), vtable: &'static RawWakerVTable) -> Self {
+        LocalWaker { waker: RawWaker { data, vtable } }
+    }
+
     /// Creates a new `LocalWaker` from [`RawWaker`].
     ///
     /// The behavior of the returned `LocalWaker` is undefined if the contract defined
@@ -831,12 +878,20 @@ impl LocalWaker {
         WAKER
     }
 
-    /// Gets a reference to the underlying [`RawWaker`].
+    /// Gets the `data` pointer used to create this `LocalWaker`.
     #[inline]
     #[must_use]
-    #[unstable(feature = "waker_getters", issue = "96992")]
-    pub fn as_raw(&self) -> &RawWaker {
-        &self.waker
+    #[unstable(feature = "local_waker", issue = "118959")]
+    pub fn data(&self) -> *const () {
+        self.waker.data
+    }
+
+    /// Gets the `vtable` pointer used to create this `LocalWaker`.
+    #[inline]
+    #[must_use]
+    #[unstable(feature = "local_waker", issue = "118959")]
+    pub fn vtable(&self) -> &'static RawWakerVTable {
+        self.waker.vtable
     }
 }
 #[unstable(feature = "local_waker", issue = "118959")]

library/core/tests/lib.rs

@@ -112,7 +112,6 @@
 #![feature(unsize)]
 #![feature(unsized_tuple_coercion)]
 #![feature(unwrap_infallible)]
-#![feature(waker_getters)]
 // tidy-alphabetical-end
 #![allow(internal_features)]
 #![deny(fuzzy_provenance_casts)]

library/core/tests/waker.rs

@@ -4,14 +4,13 @@ use std::task::{RawWaker, RawWakerVTable, Waker};
 #[test]
 fn test_waker_getters() {
     let raw_waker = RawWaker::new(ptr::without_provenance_mut(42usize), &WAKER_VTABLE);
-    assert_eq!(raw_waker.data() as usize, 42);
-    assert!(ptr::eq(raw_waker.vtable(), &WAKER_VTABLE));
-
     let waker = unsafe { Waker::from_raw(raw_waker) };
+    assert_eq!(waker.data() as usize, 42);
+    assert!(ptr::eq(waker.vtable(), &WAKER_VTABLE));
+
     let waker2 = waker.clone();
-    let raw_waker2 = waker2.as_raw();
-    assert_eq!(raw_waker2.data() as usize, 43);
-    assert!(ptr::eq(raw_waker2.vtable(), &WAKER_VTABLE));
+    assert_eq!(waker2.data() as usize, 43);
+    assert!(ptr::eq(waker2.vtable(), &WAKER_VTABLE));
 }
 
 static WAKER_VTABLE: RawWakerVTable = RawWakerVTable::new(