Struct wgpu_core::identity::IdentityManager

pub struct IdentityManager {
    free: Vec<u32>,
    epochs: Vec<u32>,
}

A simple structure to allocate Id identifiers.

Calling alloc returns a fresh, never-before-seen id. Calling free marks an id as dead; it will never be returned again by alloc.

Use IdentityManager::default to construct new instances.

IdentityManager returns Ids whose index values are suitable for use as indices into a Storage<T> that holds those ids’ referents:

• Every live id has a distinct index value. Each live id’s index selects a distinct element in the vector.

• IdentityManager prefers low index numbers. If you size your vector to accommodate the indices produced here, the vector’s length will reflect the highwater mark of actual occupancy.

• IdentityManager reuses the index values of freed ids before returning ids with new index values. Freed vector entries get reused.

See the module-level documentation for an overview of how this fits together.

Fields

free: Vec<u32>

Available index values. If empty, then epochs.len() is the next index to allocate.

epochs: Vec<u32>

The next or currently-live epoch value associated with each Id index.

If there is a live id with index i, then epochs[i] is its epoch; any id with the same index but an older epoch is dead.

If index i is currently unused, epochs[i] is the epoch to use in its next Id.

Implementations

impl IdentityManager

pub fn alloc<I: TypedId>(&mut self, backend: Backend) -> I

Allocate a fresh, never-before-seen id with the given backend.

The backend is incorporated into the id, so that ids allocated with different backend values are always distinct.

pub fn free<I: TypedId + Debug>(&mut self, id: I)

Free id. It will never be returned from alloc again.

Trait Implementations

impl Debug for IdentityManager

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

Formats the value using the given formatter.

impl Default for IdentityManager

fn default() -> IdentityManager

Returns the “default value” for a type.