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import { assertEquals, spy } from "./deps.ts";import { CallbackContext } from "./types.ts";
class DdcCallbackCancelError extends Error {  constructor(message?: string) {    super(message);
    if (Error.captureStackTrace) {      Error.captureStackTrace(this, DdcCallbackCancelError);    }  }}Object.defineProperty(DdcCallbackCancelError.prototype, "name", {  value: "DdcCallbackCancelError",  configurable: true,  enumerable: false,  writable: true,});
export const isDdcCallbackCancelError = (  v: unknown,): v is DdcCallbackCancelError => {  return typeof v === "object" && v instanceof Error &&    // deno-lint-ignore no-explicit-any    (v as any).name === "DdcCallbackCancelError";};
type PromiseHandler<T> = {  resolve: (value: T) => void;  cancel: () => void;};
export const createCallbackContext = (): CallbackContext => {  const handlersMap = new Map<string, Set<PromiseHandler<unknown>>>();  let symbol = Symbol();
  const revoke = () => {    symbol = Symbol();    for (const [_id, handlers] of [...handlersMap]) {      for (const handler of [...handlers]) {        handler.cancel();      }      handlers.clear();    }    handlersMap.clear();  };  const emit = (id: string, payload?: unknown) => {    const handlers = handlersMap.get(id);    if (!handlers) return;    for (const handler of [...handlers]) {      handler.resolve(payload);    }    handlers.clear();    handlersMap.delete(id);  };  const createOnCallback = () => {    const currentSymbol = symbol;    const onCallback = (id: string) => {      if (currentSymbol !== symbol) {        return Promise.reject(          new DdcCallbackCancelError(`Callback for ${id} is cancelled.`),        );      }      const handlers = handlersMap.get(id) ?? new Set();      handlersMap.set(id, handlers);      const promise = new Promise((resolveOrig, rejectOrig) => {        let resolved = false as boolean;        const resolve = (value: unknown) => {          resolveOrig(value);          resolved = true;        };        const cancel = () => {          if (resolved) return;          rejectOrig(            new DdcCallbackCancelError(`Callback for ${id} is cancelled.`),          );        };        const handler = {          resolve,          cancel,        };        handlers.add(handler);      });      return promise;    };    return onCallback;  };
  return {    emit,    revoke,    createOnCallback,  };};
Deno.test("onCallback and emit", async () => {  const runMicrotasks = () => new Promise((resolve) => setTimeout(resolve, 0));  const ok = spy();  const ng = spy();  const ctx = createCallbackContext();
  const onCallback = ctx.createOnCallback();  ctx.emit("1", "too early");  onCallback("1").then(ok).catch(ng);
  assertEquals(ok.calls.length, 0);
  await runMicrotasks();  assertEquals(ok.calls.length, 0);
  ctx.emit("1", "payload1");  ctx.emit("1", "payload2");  assertEquals(ok.calls.length, 0);
  await runMicrotasks();  assertEquals(ok.calls.length, 1);  assertEquals(ok.calls[0].args, ["payload1"]);
  ctx.emit("1", "payload3");  await runMicrotasks();  assertEquals(ok.calls.length, 1);  assertEquals(ng.calls.length, 0);});
Deno.test("onCallback and revoke", async () => {  const runMicrotasks = () => new Promise((resolve) => setTimeout(resolve, 0));  const ok1 = spy();  const ng1 = spy();  const ok2 = spy();  const ng2 = spy();  const ctx = createCallbackContext();
  const onCallback = ctx.createOnCallback();  onCallback("1").then(ok1).catch(ng1);
  assertEquals(ok1.calls.length, 0);
  ctx.emit("2", "other id");  await runMicrotasks();  assertEquals(ok1.calls.length, 0);
  ctx.revoke();  onCallback("2").then(ok2).catch(ng2);  await runMicrotasks();
  assertEquals(ng1.calls.length, 1);  assertEquals(ng1.calls[0].args.length, 1);  assertEquals(isDdcCallbackCancelError(ng1.calls[0].args[0]), true);
  assertEquals(ng2.calls.length, 1);  assertEquals(ng2.calls[0].args.length, 1);  assertEquals(isDdcCallbackCancelError(ng2.calls[0].args[0]), true);});
Deno.test("multiple onCallback and multiple emit", async () => {  const runMicrotasks = () => new Promise((resolve) => setTimeout(resolve, 0));  const ok1 = spy();  const ok2 = spy();  const ok3 = spy();  const ctx = createCallbackContext();
  ctx.createOnCallback()("1").then(ok1);  ctx.createOnCallback()("1").then(ok2);
  ctx.emit("1", "payload1");  ctx.emit("1", "payload2");
  ctx.createOnCallback()("1").then(ok3);
  ctx.emit("1", "payload3");
  ctx.revoke();  await runMicrotasks();
  assertEquals(ok1.calls.length, 1);  assertEquals(ok2.calls.length, 1);  assertEquals(ok3.calls.length, 1);
  assertEquals(ok1.calls[0].args, ["payload1"]);  assertEquals(ok2.calls[0].args, ["payload1"]);  assertEquals(ok3.calls[0].args, ["payload3"]);});