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// Copyright 2008 The Closure Library Authors. All Rights Reserved.
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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//      http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS-IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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/**
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 * @fileoverview A simple callback mechanism for notification about module
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 * loads. Should be considered package-private to goog.module.
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 *
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 */
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goog.provide('goog.module.ModuleLoadCallback');
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goog.require('goog.debug.entryPointRegistry');
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/** @suppress {extraRequire} */
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goog.require('goog.module');
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/**
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 * Class used to encapsulate the callbacks to be called when a module loads.
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 * @param {Function} fn Callback function.
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 * @param {Object=} opt_handler Optional handler under whose scope to execute
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 *     the callback.
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 * @constructor
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 * @final
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 */
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goog.module.ModuleLoadCallback = function(fn, opt_handler) {
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  /**
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   * Callback function.
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   * @type {Function}
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   * @private
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   */
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  this.fn_ = fn;
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  /**
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   * Optional handler under whose scope to execute the callback.
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   * @type {Object|undefined}
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   * @private
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   */
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  this.handler_ = opt_handler;
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};
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/**
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 * Completes the operation and calls the callback function if appropriate.
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 * @param {*} context The module context.
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 */
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goog.module.ModuleLoadCallback.prototype.execute = function(context) {
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  if (this.fn_) {
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    this.fn_.call(this.handler_ || null, context);
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    this.handler_ = null;
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    this.fn_ = null;
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  }
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};
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/**
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 * Abort the callback, but not the actual module load.
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 */
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goog.module.ModuleLoadCallback.prototype.abort = function() {
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  this.fn_ = null;
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  this.handler_ = null;
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};
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// Register the browser event handler as an entry point, so that
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// it can be monitored for exception handling, etc.
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goog.debug.entryPointRegistry.register(
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    /**
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     * @param {function(!Function): !Function} transformer The transforming
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     *     function.
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     */
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    function(transformer) {
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      goog.module.ModuleLoadCallback.prototype.execute =
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          transformer(goog.module.ModuleLoadCallback.prototype.execute);
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    });
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