chore: initial commit

bot/function/cancellation.ts

@@ -0,0 +1,52 @@
+import {EventEmitter} from 'node:events';
+import {AsyncLocalStorage} from 'node:async_hooks';
+import type {Bot} from '@wp2508/mineflayer';
+
+type Cancellation = {generation: number; events: EventEmitter};
+const scopes = new AsyncLocalStorage<{bot: Bot; cancellation: Cancellation}>();
+const states = new WeakMap<Bot, Cancellation & {scopes: Set<Cancellation>}>();
+function state(bot: Bot) {
+    let value = states.get(bot);
+    if (!value) states.set(bot, value = {generation: 0, events: new EventEmitter(), scopes: new Set()});
+    return value;
+}
+
+function current(bot: Bot): Cancellation {
+    const scope = scopes.getStore();
+    return scope?.bot === bot ? scope.cancellation : state(bot);
+}
+
+export function cancellation_generation(bot: Bot): number {
+    return current(bot).generation;
+}
+
+export function on_function_cancel(bot: Bot, listener: () => void): () => void {
+    const {events} = current(bot);
+    events.on('cancel', listener);
+    return () => { events.removeListener('cancel', listener); };
+}
+
+/** Existing helpers inherit the call's cancellation scope across awaits. */
+export function create_function_cancellation(bot: Bot) {
+    const value = state(bot);
+    const cancellation: Cancellation = {generation: 0, events: new EventEmitter()};
+    value.scopes.add(cancellation);
+    return {
+        run<T>(operation: () => T): T { return scopes.run({bot, cancellation}, operation); },
+        cancel() {
+            cancellation.generation++;
+            cancellation.events.emit('cancel');
+        },
+        dispose() { value.scopes.delete(cancellation); },
+    };
+}
+
+export function cancel_functions(bot: Bot): void {
+    const value = state(bot);
+    value.generation++;
+    value.events.emit('cancel');
+    for (const cancellation of value.scopes) {
+        cancellation.generation++;
+        cancellation.events.emit('cancel');
+    }
+}