pub enum RawEntryMut<'a, K, V, S, A = Global>
where A: Allocator,
{ Occupied(RawOccupiedEntryMut<'a, K, V, S, A>), Vacant(RawVacantEntryMut<'a, K, V, S, A>), }
Expand description

A view into a single entry in a map, which may either be vacant or occupied.

This is a lower-level version of Entry.

This enum is constructed through the raw_entry_mut method on HashMap, then calling one of the methods of that RawEntryBuilderMut.

Examples

use core::hash::{BuildHasher, Hash};
use hashbrown::hash_map::{HashMap, RawEntryMut, RawOccupiedEntryMut};

let mut map = HashMap::new();
map.extend([('a', 1), ('b', 2), ('c', 3)]);
assert_eq!(map.len(), 3);

fn compute_hash<K: Hash + ?Sized, S: BuildHasher>(hash_builder: &S, key: &K) -> u64 {
    use core::hash::Hasher;
    let mut state = hash_builder.build_hasher();
    key.hash(&mut state);
    state.finish()
}

// Existing key (insert)
let raw: RawEntryMut<_, _, _> = map.raw_entry_mut().from_key(&'a');
let _raw_o: RawOccupiedEntryMut<_, _, _> = raw.insert('a', 10);
assert_eq!(map.len(), 3);

// Nonexistent key (insert)
map.raw_entry_mut().from_key(&'d').insert('d', 40);
assert_eq!(map.len(), 4);

// Existing key (or_insert)
let hash = compute_hash(map.hasher(), &'b');
let kv = map
    .raw_entry_mut()
    .from_key_hashed_nocheck(hash, &'b')
    .or_insert('b', 20);
assert_eq!(kv, (&mut 'b', &mut 2));
*kv.1 = 20;
assert_eq!(map.len(), 4);

// Nonexistent key (or_insert)
let hash = compute_hash(map.hasher(), &'e');
let kv = map
    .raw_entry_mut()
    .from_key_hashed_nocheck(hash, &'e')
    .or_insert('e', 50);
assert_eq!(kv, (&mut 'e', &mut 50));
assert_eq!(map.len(), 5);

// Existing key (or_insert_with)
let hash = compute_hash(map.hasher(), &'c');
let kv = map
    .raw_entry_mut()
    .from_hash(hash, |q| q == &'c')
    .or_insert_with(|| ('c', 30));
assert_eq!(kv, (&mut 'c', &mut 3));
*kv.1 = 30;
assert_eq!(map.len(), 5);

// Nonexistent key (or_insert_with)
let hash = compute_hash(map.hasher(), &'f');
let kv = map
    .raw_entry_mut()
    .from_hash(hash, |q| q == &'f')
    .or_insert_with(|| ('f', 60));
assert_eq!(kv, (&mut 'f', &mut 60));
assert_eq!(map.len(), 6);

println!("Our HashMap: {:?}", map);

let mut vec: Vec<_> = map.iter().map(|(&k, &v)| (k, v)).collect();
// The `Iter` iterator produces items in arbitrary order, so the
// items must be sorted to test them against a sorted array.
vec.sort_unstable();
assert_eq!(vec, [('a', 10), ('b', 20), ('c', 30), ('d', 40), ('e', 50), ('f', 60)]);

Variants§

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Occupied(RawOccupiedEntryMut<'a, K, V, S, A>)

An occupied entry.

Examples

use hashbrown::{hash_map::RawEntryMut, HashMap};
let mut map: HashMap<_, _> = [("a", 100), ("b", 200)].into();

match map.raw_entry_mut().from_key(&"a") {
    RawEntryMut::Vacant(_) => unreachable!(),
    RawEntryMut::Occupied(_) => { }
}
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Vacant(RawVacantEntryMut<'a, K, V, S, A>)

A vacant entry.

Examples

use hashbrown::{hash_map::RawEntryMut, HashMap};
let mut map: HashMap<&str, i32> = HashMap::new();

match map.raw_entry_mut().from_key("a") {
    RawEntryMut::Occupied(_) => unreachable!(),
    RawEntryMut::Vacant(_) => { }
}

Implementations§

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impl<'a, K, V, S, A> RawEntryMut<'a, K, V, S, A>
where A: Allocator,

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pub fn insert(self, key: K, value: V) -> RawOccupiedEntryMut<'a, K, V, S, A>
where K: Hash, S: BuildHasher,

Sets the value of the entry, and returns a RawOccupiedEntryMut.

Examples
use hashbrown::HashMap;

let mut map: HashMap<&str, u32> = HashMap::new();
let entry = map.raw_entry_mut().from_key("horseyland").insert("horseyland", 37);

assert_eq!(entry.remove_entry(), ("horseyland", 37));
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pub fn or_insert(self, default_key: K, default_val: V) -> (&'a mut K, &'a mut V)
where K: Hash, S: BuildHasher,

Ensures a value is in the entry by inserting the default if empty, and returns mutable references to the key and value in the entry.

Examples
use hashbrown::HashMap;

let mut map: HashMap<&str, u32> = HashMap::new();

map.raw_entry_mut().from_key("poneyland").or_insert("poneyland", 3);
assert_eq!(map["poneyland"], 3);

*map.raw_entry_mut().from_key("poneyland").or_insert("poneyland", 10).1 *= 2;
assert_eq!(map["poneyland"], 6);
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pub fn or_insert_with<F>(self, default: F) -> (&'a mut K, &'a mut V)
where F: FnOnce() -> (K, V), K: Hash, S: BuildHasher,

Ensures a value is in the entry by inserting the result of the default function if empty, and returns mutable references to the key and value in the entry.

Examples
use hashbrown::HashMap;

let mut map: HashMap<&str, String> = HashMap::new();

map.raw_entry_mut().from_key("poneyland").or_insert_with(|| {
    ("poneyland", "hoho".to_string())
});

assert_eq!(map["poneyland"], "hoho".to_string());
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pub fn and_modify<F>(self, f: F) -> RawEntryMut<'a, K, V, S, A>
where F: FnOnce(&mut K, &mut V),

Provides in-place mutable access to an occupied entry before any potential inserts into the map.

Examples
use hashbrown::HashMap;

let mut map: HashMap<&str, u32> = HashMap::new();

map.raw_entry_mut()
   .from_key("poneyland")
   .and_modify(|_k, v| { *v += 1 })
   .or_insert("poneyland", 42);
assert_eq!(map["poneyland"], 42);

map.raw_entry_mut()
   .from_key("poneyland")
   .and_modify(|_k, v| { *v += 1 })
   .or_insert("poneyland", 0);
assert_eq!(map["poneyland"], 43);
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pub fn and_replace_entry_with<F>(self, f: F) -> RawEntryMut<'a, K, V, S, A>
where F: FnOnce(&K, V) -> Option<V>,

Provides shared access to the key and owned access to the value of an occupied entry and allows to replace or remove it based on the value of the returned option.

Examples
use hashbrown::HashMap;
use hashbrown::hash_map::RawEntryMut;

let mut map: HashMap<&str, u32> = HashMap::new();

let entry = map
    .raw_entry_mut()
    .from_key("poneyland")
    .and_replace_entry_with(|_k, _v| panic!());

match entry {
    RawEntryMut::Vacant(_) => {},
    RawEntryMut::Occupied(_) => panic!(),
}

map.insert("poneyland", 42);

let entry = map
    .raw_entry_mut()
    .from_key("poneyland")
    .and_replace_entry_with(|k, v| {
        assert_eq!(k, &"poneyland");
        assert_eq!(v, 42);
        Some(v + 1)
    });

match entry {
    RawEntryMut::Occupied(e) => {
        assert_eq!(e.key(), &"poneyland");
        assert_eq!(e.get(), &43);
    },
    RawEntryMut::Vacant(_) => panic!(),
}

assert_eq!(map["poneyland"], 43);

let entry = map
    .raw_entry_mut()
    .from_key("poneyland")
    .and_replace_entry_with(|_k, _v| None);

match entry {
    RawEntryMut::Vacant(_) => {},
    RawEntryMut::Occupied(_) => panic!(),
}

assert!(!map.contains_key("poneyland"));

Trait Implementations§

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impl<K, V, S, A> Debug for RawEntryMut<'_, K, V, S, A>
where K: Debug, V: Debug, A: Allocator,

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

Formats the value using the given formatter. Read more

Auto Trait Implementations§

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impl<'a, K, V, S, A> RefUnwindSafe for RawEntryMut<'a, K, V, S, A>

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impl<'a, K, V, S, A> Send for RawEntryMut<'a, K, V, S, A>
where A: Send, K: Send, S: Send + Sync, V: Send,

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impl<'a, K, V, S, A> Sync for RawEntryMut<'a, K, V, S, A>
where A: Sync, K: Sync, S: Sync, V: Sync,

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impl<'a, K, V, S, A> Unpin for RawEntryMut<'a, K, V, S, A>

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impl<'a, K, V, S, A = Global> !UnwindSafe for RawEntryMut<'a, K, V, S, A>

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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, U> AsBindGroupShaderType<U> for T
where U: ShaderType, &'a T: for<'a> Into<U>,

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fn as_bind_group_shader_type(&self, _images: &RenderAssets<Image>) -> U

Return the T ShaderType for self. When used in AsBindGroup derives, it is safe to assume that all images in self exist.
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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> Downcast<T> for T

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fn downcast(&self) -> &T

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impl<T> Downcast for T
where T: Any,

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fn into_any(self: Box<T>) -> Box<dyn Any>

Convert Box<dyn Trait> (where Trait: Downcast) to Box<dyn Any>. Box<dyn Any> can then be further downcast into Box<ConcreteType> where ConcreteType implements Trait.
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fn into_any_rc(self: Rc<T>) -> Rc<dyn Any>

Convert Rc<Trait> (where Trait: Downcast) to Rc<Any>. Rc<Any> can then be further downcast into Rc<ConcreteType> where ConcreteType implements Trait.
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fn as_any(&self) -> &(dyn Any + 'static)

Convert &Trait (where Trait: Downcast) to &Any. This is needed since Rust cannot generate &Any’s vtable from &Trait’s.
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fn as_any_mut(&mut self) -> &mut (dyn Any + 'static)

Convert &mut Trait (where Trait: Downcast) to &Any. This is needed since Rust cannot generate &mut Any’s vtable from &mut Trait’s.
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impl<T> DowncastSync for T
where T: Any + Send + Sync,

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fn into_any_arc(self: Arc<T>) -> Arc<dyn Any + Send + Sync>

Convert Arc<Trait> (where Trait: Downcast) to Arc<Any>. Arc<Any> can then be further downcast into Arc<ConcreteType> where ConcreteType implements Trait.
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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<S> FromSample<S> for S

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fn from_sample_(s: S) -> S

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impl<T> Instrument for T

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fn instrument(self, span: Span) -> Instrumented<Self>

Instruments this type with the provided Span, returning an Instrumented wrapper. Read more
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fn in_current_span(self) -> Instrumented<Self>

Instruments this type with the current Span, returning an Instrumented wrapper. Read more
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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> ToSample<U> for T
where U: FromSample<T>,

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fn to_sample_(self) -> U

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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.
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impl<T> Upcast<T> for T

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fn upcast(&self) -> Option<&T>

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impl<T> WithSubscriber for T

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fn with_subscriber<S>(self, subscriber: S) -> WithDispatch<Self>
where S: Into<Dispatch>,

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impl<T> WasmNotSync for T
where T: Sync,