Struct StableArena 

pub struct StableArena<Id: Identifier, T> { /* private fields */ }

Stable logical IDs over compact, dense physical payload storage.

Implementations

impl<Id: Identifier, T> StableArena<Id, T>

pub fn push(&mut self, value: T) -> Id

Inserts value under a fresh, monotonic identifier.

pub fn len(&self) -> usize

Returns the number of live payloads.

pub fn issued_len(&self) -> usize

Returns the number of logical IDs issued, including removed IDs.

pub fn capacity(&self) -> usize

Returns the payload capacity reserved by the dense value vector.

pub fn structural_bytes(&self) -> usize

Returns bytes reserved by the arena’s three structural vectors.

Allocations owned by T itself are deliberately excluded.

pub fn is_empty(&self) -> bool

Returns true when no live payload remains.

pub fn shrink_to_fit(&mut self)

Releases structural capacity retained beyond the current live/issued lengths.

Identifiers, liveness, and dense physical order are unchanged; only allocator capacity is returned. Intended for explicit end-of-mutation boundaries — shrinking after every removal would reallocate on the next growth.

pub fn contains(&self, id: Id) -> bool

Returns whether id currently names a live payload.

pub fn get(&self, id: Id) -> Option<Identified<Id, &T>>

Returns the live payload identified by id, if any.

pub fn get_mut(&mut self, id: Id) -> Option<Identified<Id, &mut T>>

Returns the live payload identified by id mutably, if any.

pub fn remove(&mut self, id: Id) -> T

Removes and returns id’s payload while preserving every other ID.

Panics

Panics when id is unknown or was already removed.

pub fn clear(&mut self)

Drops every payload and starts issuing ids from zero again, keeping the capacity already allocated.

Every id issued before is invalid afterwards, and will be issued again: this begins a new epoch of the arena, and a stale id from the previous one silently names a different payload. Only an owner that can vouch no such id survives may call this.

pub fn truncate_issued(&mut self, issued: usize)

Removes every payload whose id is issued or above and stops counting those ids as issued, so the next push reuses the first of them.

The payloads are removed newest first, so an arena that only ever pushed since the ids below issued were issued keeps its dense order. Like clear, this reissues ids: it is for taking back a batch of pushes whose ids never escaped.

pub fn iter(&self) -> Iter<'_, Id, T>

Iterates over live entries in dense physical order.

pub fn iter_mut(&mut self) -> IterMut<'_, Id, T>

Iterates mutably over live entries in dense physical order.

Trait Implementations

impl<Id: Clone + Identifier, T: Clone> Clone for StableArena<Id, T>

fn clone(&self) -> StableArena<Id, T>

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl<Id: Identifier, T: Debug> Debug for StableArena<Id, T>

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

Formats the value using the given formatter.

impl<Id: Identifier, T> Default for StableArena<Id, T>

fn default() -> Self

Returns the “default value” for a type.

impl<'de, Id: Identifier, T: Deserialize<'de>> Deserialize<'de> for StableArena<Id, T>

fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>

where D: Deserializer<'de>,

Deserialize this value from the given Serde deserializer.

impl<Id: Eq + Identifier, T: Eq> Eq for StableArena<Id, T>

impl<Id: Identifier, T> FromIterator<T> for StableArena<Id, T>

fn from_iter<I: IntoIterator<Item = T>>(iter: I) -> Self

Creates a value from an iterator.

impl<Id: Identifier, T> Index<Id> for StableArena<Id, T>

type Output = T

The returned type after indexing.

fn index(&self, id: Id) -> &Self::Output

Performs the indexing (container[index]) operation.

impl<Id: Identifier, T> IndexMut<Id> for StableArena<Id, T>

fn index_mut(&mut self, id: Id) -> &mut Self::Output

Performs the mutable indexing (container[index]) operation.

impl<'a, Id: Identifier, T> IntoIterator for &'a StableArena<Id, T>

type Item = Identified<Id, &'a T>

The type of the elements being iterated over.

type IntoIter = Iter<'a, Id, T>

Which kind of iterator are we turning this into?

fn into_iter(self) -> Self::IntoIter

Creates an iterator from a value.

impl<'a, Id: Identifier, T> IntoIterator for &'a mut StableArena<Id, T>

type Item = Identified<Id, &'a mut T>

The type of the elements being iterated over.

type IntoIter = IterMut<'a, Id, T>

Which kind of iterator are we turning this into?

fn into_iter(self) -> Self::IntoIter

Creates an iterator from a value.

impl<Id: Identifier, T> IntoIterator for StableArena<Id, T>

type Item = Identified<Id, T>

The type of the elements being iterated over.

type IntoIter = IntoIter<Id, T>

Which kind of iterator are we turning this into?

fn into_iter(self) -> Self::IntoIter

Creates an iterator from a value.

impl<Id: PartialEq + Identifier, T: PartialEq> PartialEq for StableArena<Id, T>

fn eq(&self, other: &StableArena<Id, T>) -> bool

Equality operator ==.

fn ne(&self, other: &Rhs) -> bool

Inequality operator !=.

impl<Id: Identifier, T: Serialize> Serialize for StableArena<Id, T>

fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>

where S: Serializer,

Serialize this value into the given Serde serializer.

impl<Id: PartialEq + Identifier, T: PartialEq> StructuralPartialEq for StableArena<Id, T>