Struct once_cell::race::OnceBool

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pub struct OnceBool { /* private fields */ }
Expand description

A thread-safe cell which can be written to only once.

Implementations§

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impl OnceBool

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pub const fn new() -> OnceBool

Creates a new empty cell.

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pub fn get(&self) -> Option<bool>

Gets the underlying value.

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pub fn set(&self, value: bool) -> Result<(), ()>

Sets the contents of this cell to value.

Returns Ok(()) if the cell was empty and Err(()) if it was full.

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pub fn get_or_init<F>(&self, f: F) -> bool
where F: FnOnce() -> bool,

Gets the contents of the cell, initializing it with f if the cell was empty.

If several threads concurrently run get_or_init, more than one f can be called. However, all threads will return the same value, produced by some f.

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pub fn get_or_try_init<F, E>(&self, f: F) -> Result<bool, E>
where F: FnOnce() -> Result<bool, E>,

Gets the contents of the cell, initializing it with f if the cell was empty. If the cell was empty and f failed, an error is returned.

If several threads concurrently run get_or_init, more than one f can be called. However, all threads will return the same value, produced by some f.

Trait Implementations§

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impl Debug for OnceBool

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fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter. Read more
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impl Default for OnceBool

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fn default() -> OnceBool

Returns the “default value” for a type. Read more

Auto Trait Implementations§

Blanket Implementations§

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impl<T> Any for T
where T: 'static + ?Sized,

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fn type_id(&self) -> TypeId

Gets the TypeId of self. Read more
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impl<T> Borrow<T> for T
where T: ?Sized,

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fn borrow(&self) -> &T

Immutably borrows from an owned value. Read more
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impl<T> BorrowMut<T> for T
where T: ?Sized,

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fn borrow_mut(&mut self) -> &mut T

Mutably borrows from an owned value. Read more
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impl<T> From<T> for T

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fn from(t: T) -> T

Returns the argument unchanged.

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impl<T, U> Into<U> for T
where U: From<T>,

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fn into(self) -> U

Calls U::from(self).

That is, this conversion is whatever the implementation of From<T> for U chooses to do.

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impl<T, U> TryFrom<U> for T
where U: Into<T>,

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type Error = Infallible

The type returned in the event of a conversion error.
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fn try_from(value: U) -> Result<T, <T as TryFrom<U>>::Error>

Performs the conversion.
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impl<T, U> TryInto<U> for T
where U: TryFrom<T>,

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type Error = <U as TryFrom<T>>::Error

The type returned in the event of a conversion error.
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fn try_into(self) -> Result<U, <U as TryFrom<T>>::Error>

Performs the conversion.

Layout§

Note: Most layout information is completely unstable and may even differ between compilations. The only exception is types with certain repr(...) attributes. Please see the Rust Reference's “Type Layout” chapter for details on type layout guarantees.

Size: 8 bytes