Struct slab::VacantEntry

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pub struct VacantEntry<'a, T> { /* private fields */ }
Expand description

A handle to a vacant entry in a Slab.

VacantEntry allows constructing values with the key that they will be assigned to.

Examples

let mut slab = Slab::new();

let hello = {
    let entry = slab.vacant_entry();
    let key = entry.key();

    entry.insert((key, "hello"));
    key
};

assert_eq!(hello, slab[hello].0);
assert_eq!("hello", slab[hello].1);

Implementations§

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impl<'a, T> VacantEntry<'a, T>

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pub fn insert(self, val: T) -> &'a mut T

Insert a value in the entry, returning a mutable reference to the value.

To get the key associated with the value, use key prior to calling insert.

Examples
let mut slab = Slab::new();

let hello = {
    let entry = slab.vacant_entry();
    let key = entry.key();

    entry.insert((key, "hello"));
    key
};

assert_eq!(hello, slab[hello].0);
assert_eq!("hello", slab[hello].1);
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pub fn key(&self) -> usize

Return the key associated with this entry.

A value stored in this entry will be associated with this key.

Examples
let mut slab = Slab::new();

let hello = {
    let entry = slab.vacant_entry();
    let key = entry.key();

    entry.insert((key, "hello"));
    key
};

assert_eq!(hello, slab[hello].0);
assert_eq!("hello", slab[hello].1);

Trait Implementations§

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impl<'a, T: Debug> Debug for VacantEntry<'a, T>

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

Formats the value using the given formatter. Read more

Auto Trait Implementations§

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impl<'a, T> RefUnwindSafe for VacantEntry<'a, T>where T: RefUnwindSafe,

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impl<'a, T> Send for VacantEntry<'a, T>where T: Send,

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impl<'a, T> Sync for VacantEntry<'a, T>where T: Sync,

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impl<'a, T> Unpin for VacantEntry<'a, T>

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impl<'a, T> !UnwindSafe for VacantEntry<'a, T>

Blanket Implementations§

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impl<T> Any for Twhere 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 Twhere 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 Twhere 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 Twhere 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 Twhere 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 Twhere 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.