javascript/firefox-driver/js/timer.js

/*
 Copyright 2010 WebDriver committers
 Copyright 2010 Google Inc.

 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.
 */

/**
 * @fileoverview An implementation of a timer that can be used without an
 * associated window.
 *
 * Please note that the client must hold onto the reference
 * to this timer class for the full duration of the timeout,
 * or nasty stuff will happen.
 *
 */

goog.provide('fxdriver.Timer');


fxdriver.Timer = function() {
  this.timer = null;
};


/**
 * Set a callback to be executed after a specified time out. The default time
 * out is 10ms.
 *
 * Note that "this" within the callback is null
 *
 * @param {!function(*=): *} callback The callback to use.
 * @param {number=} opt_timeout An optional timeout to use.
 */
fxdriver.Timer.prototype.setTimeout = function(callback, opt_timeout) {
  var CC = Components.classes;
  var CI = Components.interfaces;

  var timeout = opt_timeout || 10;
  // NO. This cannot be changed to a local variable, Simon.
  // See documentation on msITimer.
  this.timer = CC['@mozilla.org/timer;1'].createInstance(CI['nsITimer']);

  this.timer.initWithCallback({
    notify: function() {
      callback.apply(null);
    }
  }, timeout, CI.nsITimer.TYPE_ONE_SHOT);
};


/**
 * Wait until a condition is true before calling "callback". On error, call
 * ontimeout. The callback will be called with the result of condition.
 *
 * Note that "this" is null within the callbacks
 *
 * @param {function():boolean} condition The condition to check.
 * @param {function(*):undefined} callback The callback to use when condition is
 *    true.
 * @param {number} timeout Time to wait in milliseconds.
 * @param {function():undefined} ontimeout Called if condition doesn't become
 *    true.
 */
fxdriver.Timer.prototype.runWhenTrue = function(condition, callback, timeout, ontimeout) {
  var remaining = timeout;
  var interval = 100;
  var me = this;

  var timed = function () {
    var result = condition();
    if (remaining >= 0 && !result) {
      remaining -= interval;
      me.setTimeout(timed, interval);
    } else if (remaining <= 0) {
      ontimeout();
    } else {
      callback(result);
    }
  };
  timed();
};


/**
 * Allow an existing timer to be cancelled. Calling without a timer having been
 * started is a no-op.
 */
fxdriver.Timer.prototype.cancel = function() {
  if (this.timer) {
    this.timer.cancel();
  }
};