impl<T> OnceCell<T> {
/// Creates a new empty cell.
- #[unstable(feature = "once_cell", issue = "74465")]
+ #[inline]
#[must_use]
+ #[unstable(feature = "once_cell", issue = "74465")]
pub const fn new() -> OnceCell<T> {
OnceCell { inner: UnsafeCell::new(None) }
}
/// Gets the reference to the underlying value.
///
/// Returns `None` if the cell is empty.
+ #[inline]
#[unstable(feature = "once_cell", issue = "74465")]
pub fn get(&self) -> Option<&T> {
// SAFETY: Safe due to `inner`'s invariant
/// Gets the mutable reference to the underlying value.
///
/// Returns `None` if the cell is empty.
+ #[inline]
#[unstable(feature = "once_cell", issue = "74465")]
pub fn get_mut(&mut self) -> Option<&mut T> {
self.inner.get_mut().as_mut()
///
/// assert!(cell.get().is_some());
/// ```
+ #[inline]
#[unstable(feature = "once_cell", issue = "74465")]
pub fn set(&self, value: T) -> Result<(), T> {
// SAFETY: Safe because we cannot have overlapping mutable borrows
/// let value = cell.get_or_init(|| unreachable!());
/// assert_eq!(value, &92);
/// ```
+ #[inline]
#[unstable(feature = "once_cell", issue = "74465")]
pub fn get_or_init<F>(&self, f: F) -> &T
where
/// cell.set("hello".to_string()).unwrap();
/// assert_eq!(cell.into_inner(), Some("hello".to_string()));
/// ```
+ #[inline]
#[unstable(feature = "once_cell", issue = "74465")]
pub fn into_inner(self) -> Option<T> {
// Because `into_inner` takes `self` by value, the compiler statically verifies
/// assert_eq!(cell.take(), Some("hello".to_string()));
/// assert_eq!(cell.get(), None);
/// ```
+ #[inline]
#[unstable(feature = "once_cell", issue = "74465")]
pub fn take(&mut self) -> Option<T> {
mem::take(self).into_inner()
#[unstable(feature = "once_cell", issue = "74465")]
impl<T> Default for OnceCell<T> {
+ #[inline]
fn default() -> Self {
Self::new()
}
#[unstable(feature = "once_cell", issue = "74465")]
impl<T: Clone> Clone for OnceCell<T> {
+ #[inline]
fn clone(&self) -> OnceCell<T> {
let res = OnceCell::new();
if let Some(value) = self.get() {
#[unstable(feature = "once_cell", issue = "74465")]
impl<T: PartialEq> PartialEq for OnceCell<T> {
+ #[inline]
fn eq(&self, other: &Self) -> bool {
self.get() == other.get()
}
#[unstable(feature = "once_cell", issue = "74465")]
impl<T> const From<T> for OnceCell<T> {
/// Creates a new `OnceCell<T>` which already contains the given `value`.
+ #[inline]
fn from(value: T) -> Self {
OnceCell { inner: UnsafeCell::new(Some(value)) }
}