Struct AbsentEntry

pub struct AbsentEntry<'a, T, A = Global>
where
    A: Allocator,
{ /* private fields */ }

Type representing the absence of an entry, as returned by HashTable::find_entry.

This type only exists due to limitations in Rust’s NLL borrow checker. In the future, find_entry will return an Option<OccupiedEntry> and this type will be removed.

Examples

use hashbrown::hash_table::{AbsentEntry, Entry};
use hashbrown::{HashTable, DefaultHashBuilder};
use std::hash::BuildHasher;

let mut table: HashTable<&str> = HashTable::new();
let hasher = DefaultHashBuilder::default();
let hasher = |val: &_| hasher.hash_one(val);

let entry_v: AbsentEntry<_, _> = table.find_entry(hasher(&"a"), |&x| x == "a").unwrap_err();
entry_v
    .into_table()
    .insert_unique(hasher(&"a"), "a", hasher);
assert!(table.find(hasher(&"a"), |&x| x == "a").is_some() && table.len() == 1);

// Nonexistent key (insert)
match table.entry(hasher(&"b"), |&x| x == "b", hasher) {
    Entry::Vacant(view) => {
        view.insert("b");
    }
    Entry::Occupied(_) => unreachable!(),
}
assert!(table.find(hasher(&"b"), |&x| x == "b").is_some() && table.len() == 2);

Implementations

impl<'a, T, A> AbsentEntry<'a, T, A>

where A: Allocator,

pub fn into_table(self) -> &'a mut HashTable<T, A>

Converts the AbsentEntry into a mutable reference to the underlying table.

Trait Implementations

impl<T: Debug, A: Allocator> Debug for AbsentEntry<'_, T, A>

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

Formats the value using the given formatter.

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