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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-05-18 02:49:50 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-05-18 02:49:50 +0000 |
commit | 9835e2ae736235810b4ea1c162ca5e65c547e770 (patch) | |
tree | 3fcebf40ed70e581d776a8a4c65923e8ec20e026 /library/core/src/cell/lazy.rs | |
parent | Releasing progress-linux version 1.70.0+dfsg2-1~progress7.99u1. (diff) | |
download | rustc-9835e2ae736235810b4ea1c162ca5e65c547e770.tar.xz rustc-9835e2ae736235810b4ea1c162ca5e65c547e770.zip |
Merging upstream version 1.71.1+dfsg1.
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'library/core/src/cell/lazy.rs')
-rw-r--r-- | library/core/src/cell/lazy.rs | 28 |
1 files changed, 28 insertions, 0 deletions
diff --git a/library/core/src/cell/lazy.rs b/library/core/src/cell/lazy.rs index 44adcfa1a..1b213f6a2 100644 --- a/library/core/src/cell/lazy.rs +++ b/library/core/src/cell/lazy.rs @@ -63,6 +63,34 @@ impl<T, F: FnOnce() -> T> LazyCell<T, F> { LazyCell { state: UnsafeCell::new(State::Uninit(f)) } } + /// Consumes this `LazyCell` returning the stored value. + /// + /// Returns `Ok(value)` if `Lazy` is initialized and `Err(f)` otherwise. + /// + /// # Examples + /// + /// ``` + /// #![feature(lazy_cell)] + /// #![feature(lazy_cell_consume)] + /// + /// use std::cell::LazyCell; + /// + /// let hello = "Hello, World!".to_string(); + /// + /// let lazy = LazyCell::new(|| hello.to_uppercase()); + /// + /// assert_eq!(&*lazy, "HELLO, WORLD!"); + /// assert_eq!(LazyCell::into_inner(lazy).ok(), Some("HELLO, WORLD!".to_string())); + /// ``` + #[unstable(feature = "lazy_cell_consume", issue = "109736")] + pub fn into_inner(this: Self) -> Result<T, F> { + match this.state.into_inner() { + State::Init(data) => Ok(data), + State::Uninit(f) => Err(f), + State::Poisoned => panic!("LazyCell instance has previously been poisoned"), + } + } + /// Forces the evaluation of this lazy value and returns a reference to /// the result. /// |