refactor: re-use Puppteer Mutex (#2444)

src/ToolHandler.ts

@@ -18,7 +18,7 @@ import {labels, OFF_BY_DEFAULT_CATEGORIES} from './tools/categories.js';
 import type {DefinedPageTool, ToolDefinition} from './tools/ToolDefinition.js';
 import {pageIdSchema} from './tools/ToolDefinition.js';
 import {logger} from './utils/logger.js';
-import type {Mutex} from './utils/Mutex.js';
+import type {Mutex} from './third_party/index.js';
 
 export function buildFlag(category: ToolCategory) {
   return `category${category.charAt(0).toUpperCase() + category.slice(1)}`;
@@ -310,7 +310,7 @@ export class ToolHandler {
         success,
         latencyMs: bucketizeLatency(Date.now() - startTime),
       });
-      guard.dispose();
+      guard[Symbol.dispose]();
     }
   }
 }

src/index.ts

@@ -24,7 +24,7 @@ import {ToolHandler} from './ToolHandler.js';
 import type {DefinedPageTool, ToolDefinition} from './tools/ToolDefinition.js';
 import {createTools} from './tools/tools.js';
 import {logger} from './utils/logger.js';
-import {Mutex} from './utils/Mutex.js';
+import {Mutex} from './third_party/index.js';
 import {VERSION} from './version.js';
 
 export {buildFlag} from './ToolHandler.js';

src/third_party/index.ts

@@ -49,7 +49,7 @@ export type {CdpPage} from 'puppeteer-core/internal/cdp/Page.js';
 export type {CdpWebWorker} from 'puppeteer-core/internal/cdp/WebWorker.js';
 export type {Realm} from 'puppeteer-core/internal/api/Realm.js';
 export type {JSONSchema7, JSONSchema7Definition} from 'json-schema';
-
+export {Mutex} from 'puppeteer-core/internal/util/Mutex.js';
 export {
   resolveDefaultUserDataDir,
   detectBrowserPlatform,

src/utils/Mutex.ts

@@ -1,41 +0,0 @@
-/**
- * @license
- * Copyright 2025 Google Inc.
- * SPDX-License-Identifier: Apache-2.0
- */
-
-export class Mutex {
-  static Guard = class Guard {
-    #mutex: Mutex;
-    constructor(mutex: Mutex) {
-      this.#mutex = mutex;
-    }
-    dispose(): void {
-      return this.#mutex.release();
-    }
-  };
-
-  #locked = false;
-  #acquirers: Array<() => void> = [];
-
-  // This is FIFO.
-  async acquire(): Promise<InstanceType<typeof Mutex.Guard>> {
-    if (!this.#locked) {
-      this.#locked = true;
-      return new Mutex.Guard(this);
-    }
-    const {resolve, promise} = Promise.withResolvers<void>();
-    this.#acquirers.push(resolve);
-    await promise;
-    return new Mutex.Guard(this);
-  }
-
-  release(): void {
-    const resolve = this.#acquirers.shift();
-    if (!resolve) {
-      this.#locked = false;
-      return;
-    }
-    resolve();
-  }
-}

tests/ToolHandler.test.ts

@@ -19,7 +19,7 @@ import type {
   DefinedPageTool,
   ToolDefinition,
 } from '../src/tools/ToolDefinition.js';
-import {Mutex} from '../src/utils/Mutex.js';
+import {Mutex} from '../src/third_party/index.js';
 
 describe('ToolHandler', () => {
   afterEach(() => {