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// Copyright 2008 The Closure Library Authors. All Rights Reserved.
//
// 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 Class that can be used to determine when multiple iframes have
* been loaded. Refactored from static APIs in IframeLoadMonitor.
*/
goog.provide('goog.net.MultiIframeLoadMonitor');
goog.require('goog.net.IframeLoadMonitor');
/**
* Provides a wrapper around IframeLoadMonitor, to allow the caller to wait for
* multiple iframes to load.
*
* @param {Array.<HTMLIFrameElement>} iframes Array of iframe elements to
* wait until they are loaded.
* @param {function():void} callback The callback to invoke once the frames have
* loaded.
* @param {boolean=} opt_hasContent true if the monitor should wait until the
* iframes have content (body.firstChild != null).
* @constructor
*/
goog.net.MultiIframeLoadMonitor = function(iframes, callback, opt_hasContent) {
/**
* Array of IframeLoadMonitors we use to track the loaded status of any
* currently unloaded iframes.
* @type {Array.<goog.net.IframeLoadMonitor>}
* @private
*/
this.pendingIframeLoadMonitors_ = [];
/**
* Callback which is invoked when all of the iframes are loaded.
* @type {function():void}
* @private
*/
this.callback_ = callback;
for (var i = 0; i < iframes.length; i++) {
var iframeLoadMonitor = new goog.net.IframeLoadMonitor(
iframes[i], opt_hasContent);
if (iframeLoadMonitor.isLoaded()) {
// Already loaded - don't need to wait
iframeLoadMonitor.dispose();
} else {
// Iframe isn't loaded yet - register to be notified when it is
// loaded, and track this monitor so we can dispose later as
// required.
this.pendingIframeLoadMonitors_.push(iframeLoadMonitor);
goog.events.listen(
iframeLoadMonitor, goog.net.IframeLoadMonitor.LOAD_EVENT, this);
}
}
if (!this.pendingIframeLoadMonitors_.length) {
// All frames were already loaded
this.callback_();
}
};
/**
* Handles a pending iframe load monitor load event.
* @param {goog.events.Event} e The goog.net.IframeLoadMonitor.LOAD_EVENT event.
*/
goog.net.MultiIframeLoadMonitor.prototype.handleEvent = function(e) {
var iframeLoadMonitor = e.target;
// iframeLoadMonitor is now loaded, remove it from the array of
// pending iframe load monitors.
for (var i = 0; i < this.pendingIframeLoadMonitors_.length; i++) {
if (this.pendingIframeLoadMonitors_[i] == iframeLoadMonitor) {
this.pendingIframeLoadMonitors_.splice(i, 1);
break;
}
}
// Disposes of the iframe load monitor. We created this iframe load monitor
// and installed the single listener on it, so it is safe to dispose it
// in the middle of this event handler.
iframeLoadMonitor.dispose();
// If there are no more pending iframe load monitors, all the iframes
// have loaded, and so we invoke the callback.
if (!this.pendingIframeLoadMonitors_.length) {
this.callback_();
}
};
/**
* Stops monitoring the iframes, cleaning up any associated resources. In
* general, the object cleans up its own resources before invoking the
* callback, so this API should only be used if the caller wants to stop the
* monitoring before the iframes are loaded (for example, if the caller is
* implementing a timeout).
*/
goog.net.MultiIframeLoadMonitor.prototype.stopMonitoring = function() {
for (var i = 0; i < this.pendingIframeLoadMonitors_.length; i++) {
this.pendingIframeLoadMonitors_[i].dispose();
}
this.pendingIframeLoadMonitors_.length = 0;
};
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