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Update documentation in thread/local.rs.

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This commit is contained in:
Mara Bos 2021-12-20 19:21:36 +01:00
parent 36c904594e
commit c68c384b88
1 changed files with 26 additions and 6 deletions
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32
library/std/src/thread/local.rs
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@ -443,6 +443,18 @@ impl<T: 'static> LocalKey<T> {
}
}
/// Acquires a reference to the value in this TLS key, initializing it with
/// `init` if it wasn't already initialized on this thread.
///
/// If `init` was used to initialize the thread local variable, `None` is
/// passed as the first argument to `f`. If it was already initialized,
/// `Some(init)` is passed to `f`.
///
/// # Panics
///
/// This function will panic if the key currently has its destructor
/// running, and it **may** panic if the destructor has previously been run
/// for this thread.
fn initialize_with<F, R>(&'static self, init: T, f: F) -> R
where
F: FnOnce(Option<T>, &T) -> R,
@ -488,9 +500,12 @@ impl<T: 'static> LocalKey<Cell<T>> {
/// ```
#[unstable(feature = "local_key_cell_methods", issue = "92122")]
pub fn set(&'static self, value: T) {
self.initialize_with(Cell::new(value), |init, cell| {
if let Some(init) = init {
cell.set(init.into_inner());
self.initialize_with(Cell::new(value), |value, cell| {
if let Some(value) = value {
// The cell was already initialized, so `value` wasn't used to
// initialize it. So we overwrite the current value with the
// new one instead.
cell.set(value.into_inner());
}
});
}
@ -593,7 +608,7 @@ impl<T: 'static> LocalKey<RefCell<T>> {
///
/// # Panics
///
/// Panics if the value is currently borrowed.
/// Panics if the value is currently mutably borrowed.
///
/// Panics if the key currently has its destructor running,
/// and it **may** panic if the destructor has previously been run for this thread.
@ -660,6 +675,8 @@ impl<T: 'static> LocalKey<RefCell<T>> {
///
/// # Panics
///
/// Panics if the value is currently borrowed.
///
/// Panics if the key currently has its destructor running,
/// and it **may** panic if the destructor has previously been run for this thread.
///
@ -681,8 +698,11 @@ impl<T: 'static> LocalKey<RefCell<T>> {
/// ```
#[unstable(feature = "local_key_cell_methods", issue = "92122")]
pub fn set(&'static self, value: T) {
self.initialize_with(RefCell::new(value), |init, cell| {
if let Some(init) = init {
self.initialize_with(RefCell::new(value), |value, cell| {
if let Some(value) = value {
// The cell was already initialized, so `value` wasn't used to
// initialize it. So we overwrite the current value with the
// new one instead.
cell.replace(init.into_inner());
}
});