Struct SessionRegistry 

pub struct SessionRegistry<T> { /* private fields */ }

Per-component map of session-id → user state T.

T is whatever the component wants to keep around for a session (a database connection, a counter, a parsed config, …). T is stored by value; if it owns expensive resources, drop in SessionRegistry::remove runs your Drop impl.

Ids are allocated as "<prefix>_<counter>" where prefix is set at construction. Components SHOULD use a short, recognisable prefix; per-component uniqueness is what matters since the host scopes session-ids to one component instance.

Implementations

impl<T> SessionRegistry<T>

pub fn new(prefix: &'static str) -> Self

Create an empty registry. prefix becomes part of every allocated session-id (e.g. "ctr" → "ctr_0", "ctr_1", …).

pub fn insert(&self, value: T) -> String

Insert a fresh session, returning its allocated id.

pub fn with<R>(&self, id: &str, f: impl FnOnce(&T) -> R) -> Option<R>

Look up a session by id and apply f to a shared reference. Returns None if the id is unknown.

pub fn with_mut<R>(&self, id: &str, f: impl FnOnce(&mut T) -> R) -> Option<R>

Look up a session by id and apply f to a mutable reference. Returns None if the id is unknown.

pub fn remove(&self, id: &str) -> Option<T>

Remove a session by id. The dropped T is returned (if any).

pub fn len(&self) -> usize

Number of currently-open sessions.

pub fn is_empty(&self) -> bool

Whether the registry has no open sessions.