Struct HookBus 

pub struct HookBus { /* private fields */ }

The central hook dispatcher.

Thread-safe: uses RwLock so multiple concurrent emitters can read the handler list, and registration takes a write lock only briefly.

Implementations

impl HookBus

pub fn new() -> Self

Create an empty HookBus with no handlers.

pub async fn subscribe( &self, kind: HookKind, handler: Arc<dyn ExtensionHandler>, tool_filter: Option<String>, matcher: Option<HookMatcher>, permissions: PermissionSet, ) -> Result<(), String>

Register a handler for a specific hook kind.

Returns an error if the handler’s permissions don’t allow subscribing to this hook kind.

pub async fn emit(&self, event: &HookEvent) -> HookResult

Emit a hook event to all registered handlers.

Returns the first Block result if any handler blocks, otherwise returns Continue. Handlers are called in registration order.

If no handlers are registered for this hook, returns immediately (the no-extensions fast path).

pub async fn emit_concurrent(&self, event: &HookEvent) -> HookResult

Emit a hook event to all registered handlers concurrently.

All handlers race under a single shared timeout (per_handler_timeout). Results are collected and the first Block wins; injections are merged.

When to use this over emit():

Only safe for hook kinds whose handlers are order-independent — i.e. where no handler’s result depends on another’s execution. Currently that applies to:

• on_session_end: only Continue is a valid result; handlers are fire-and-forget notification calls (deck, d20, jawz-widget, synaps-tasks all write to their own stores independently).

Do NOT use for before_tool_call / before_message hooks where Block / Modify / Inject semantics require a defined winner when two handlers disagree.

With N extensions and a 5 s per-handler timeout, serial emit takes up to N×5 s; concurrent emit collapses that to a single 5 s window regardless of N — critical for teardown budgets.

pub async fn unsubscribe_all(&self, extension_id: &str)

Remove all handlers for a given extension ID.

pub async fn handler_count(&self) -> usize

Number of registered handlers across all hooks.

pub async fn is_empty(&self) -> bool

Check if any handlers are registered (for fast-path decisions).

pub async fn subscriptions_for( &self, extension_id: &str, ) -> Vec<(HookKind, Option<String>)>

Return all (kind, tool_filter) pairs subscribed by the given extension id. Sorted by kind name, then by tool_filter (None first), for stable output.

Trait Implementations

impl Default for HookBus

fn default() -> Self

Returns the “default value” for a type.