Struct hashbrown::hash_table::AbsentEntry
source · pub struct AbsentEntry<'a, T, A = Global>where
A: Allocator,{ /* private fields */ }
Expand description
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§
source§impl<'a, T, A> AbsentEntry<'a, T, A>where
A: Allocator,
impl<'a, T, A> AbsentEntry<'a, T, A>where
A: Allocator,
sourcepub fn into_table(self) -> &'a mut HashTable<T, A>
pub fn into_table(self) -> &'a mut HashTable<T, A>
Converts the AbsentEntry
into a mutable reference to the underlying
table.
Trait Implementations§
Auto Trait Implementations§
impl<'a, T, A> Freeze for AbsentEntry<'a, T, A>
impl<'a, T, A> RefUnwindSafe for AbsentEntry<'a, T, A>where
A: RefUnwindSafe,
T: RefUnwindSafe,
impl<'a, T, A> Send for AbsentEntry<'a, T, A>
impl<'a, T, A> Sync for AbsentEntry<'a, T, A>
impl<'a, T, A> Unpin for AbsentEntry<'a, T, A>
impl<'a, T, A = Global> !UnwindSafe for AbsentEntry<'a, T, A>
Blanket Implementations§
source§impl<T> BorrowMut<T> for Twhere
T: ?Sized,
impl<T> BorrowMut<T> for Twhere
T: ?Sized,
source§fn borrow_mut(&mut self) -> &mut T
fn borrow_mut(&mut self) -> &mut T
Mutably borrows from an owned value. Read more