pdfjs-dist/lib/web/event_utils.js

/**
 * @licstart The following is the entire license notice for the
 * JavaScript code in this page
 *
 * Copyright 2022 Mozilla Foundation
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 *
 * @licend The above is the entire license notice for the
 * JavaScript code in this page
 */
"use strict";

Object.defineProperty(exports, "__esModule", {
  value: true
});
exports.WaitOnType = exports.EventBus = exports.AutomationEventBus = void 0;
exports.waitOnEventOrTimeout = waitOnEventOrTimeout;
const WaitOnType = {
  EVENT: "event",
  TIMEOUT: "timeout"
};
exports.WaitOnType = WaitOnType;

function waitOnEventOrTimeout({
  target,
  name,
  delay = 0
}) {
  return new Promise(function (resolve, reject) {
    if (typeof target !== "object" || !(name && typeof name === "string") || !(Number.isInteger(delay) && delay >= 0)) {
      throw new Error("waitOnEventOrTimeout - invalid parameters.");
    }

    function handler(type) {
      if (target instanceof EventBus) {
        target._off(name, eventHandler);
      } else {
        target.removeEventListener(name, eventHandler);
      }

      if (timeout) {
        clearTimeout(timeout);
      }

      resolve(type);
    }

    const eventHandler = handler.bind(null, WaitOnType.EVENT);

    if (target instanceof EventBus) {
      target._on(name, eventHandler);
    } else {
      target.addEventListener(name, eventHandler);
    }

    const timeoutHandler = handler.bind(null, WaitOnType.TIMEOUT);
    const timeout = setTimeout(timeoutHandler, delay);
  });
}

class EventBus {
  constructor() {
    this._listeners = Object.create(null);
  }

  on(eventName, listener, options = null) {
    this._on(eventName, listener, {
      external: true,
      once: options?.once
    });
  }

  off(eventName, listener, options = null) {
    this._off(eventName, listener, {
      external: true,
      once: options?.once
    });
  }

  dispatch(eventName, data) {
    const eventListeners = this._listeners[eventName];

    if (!eventListeners || eventListeners.length === 0) {
      return;
    }

    let externalListeners;

    for (const {
      listener,
      external,
      once
    } of eventListeners.slice(0)) {
      if (once) {
        this._off(eventName, listener);
      }

      if (external) {
        (externalListeners ||= []).push(listener);
        continue;
      }

      listener(data);
    }

    if (externalListeners) {
      for (const listener of externalListeners) {
        listener(data);
      }

      externalListeners = null;
    }
  }

  _on(eventName, listener, options = null) {
    const eventListeners = this._listeners[eventName] ||= [];
    eventListeners.push({
      listener,
      external: options?.external === true,
      once: options?.once === true
    });
  }

  _off(eventName, listener, options = null) {
    const eventListeners = this._listeners[eventName];

    if (!eventListeners) {
      return;
    }

    for (let i = 0, ii = eventListeners.length; i < ii; i++) {
      if (eventListeners[i].listener === listener) {
        eventListeners.splice(i, 1);
        return;
      }
    }
  }

}

exports.EventBus = EventBus;

class AutomationEventBus extends EventBus {
  dispatch(eventName, data) {
    throw new Error("Not implemented: AutomationEventBus.dispatch");
  }

}

exports.AutomationEventBus = AutomationEventBus;