source: trunk/admin/inc/ckeditor/_source/core/scriptloader.js@ 239

/*
Copyright (c) 2003-2011, CKSource - Frederico Knabben. All rights reserved.
For licensing, see LICENSE.html or http://ckeditor.com/license
*/

/**
 * @fileOverview Defines the {@link CKEDITOR.scriptLoader} object, used to load scripts
 *              asynchronously.
 */

/**
 * Load scripts asynchronously.
 * @namespace
 * @example
 */
CKEDITOR.scriptLoader = (function()
{
        var uniqueScripts = {},
                waitingList = {};

        return /** @lends CKEDITOR.scriptLoader */ {
                /**
                 * Loads one or more external script checking if not already loaded
                 * previously by this function.
                 * @param {String|Array} scriptUrl One or more URLs pointing to the
                 *              scripts to be loaded.
                 * @param {Function} [callback] A function to be called when the script
                 *              is loaded and executed. If a string is passed to "scriptUrl", a
                 *              boolean parameter is passed to the callback, indicating the
                 *              success of the load. If an array is passed instead, two array
                 *              parameters are passed to the callback; the first contains the
                 *              URLs that have been properly loaded, and the second the failed
                 *              ones.
                 * @param {Object} [scope] The scope ("this" reference) to be used for
                 *              the callback call. Default to {@link CKEDITOR}.
                 * @param {Boolean} [showBusy] Changes the cursor of the document while
+                *              the script is loaded.
                 * @example
                 * CKEDITOR.scriptLoader.load( '/myscript.js' );
                 * @example
                 * CKEDITOR.scriptLoader.load( '/myscript.js', function( success )
                 *     {
                 *         // Alerts "true" if the script has been properly loaded.
                 *         // HTTP error 404 should return "false".
                 *         alert( success );
                 *     });
                 * @example
                 * CKEDITOR.scriptLoader.load( [ '/myscript1.js', '/myscript2.js' ], function( completed, failed )
                 *     {
                 *         alert( 'Number of scripts loaded: ' + completed.length );
                 *         alert( 'Number of failures: ' + failed.length );
                 *     });
                 */
                load : function( scriptUrl, callback, scope, showBusy )
                {
                        var isString = ( typeof scriptUrl == 'string' );

                        if ( isString )
                                scriptUrl = [ scriptUrl ];

                        if ( !scope )
                                scope = CKEDITOR;

                        var scriptCount = scriptUrl.length,
                                completed = [],
                                failed = [];

                        var doCallback = function( success )
                        {
                                if ( callback )
                                {
                                        if ( isString )
                                                callback.call( scope, success );
                                        else
                                                callback.call( scope, completed, failed );
                                }
                        };

                        if ( scriptCount === 0 )
                        {
                                doCallback( true );
                                return;
                        }

                        var checkLoaded = function( url, success )
                        {
                                ( success ? completed : failed ).push( url );

                                if ( --scriptCount <= 0 )
                                {
                                        showBusy && CKEDITOR.document.getDocumentElement().removeStyle( 'cursor' );
                                        doCallback( success );
                                }
                        };

                        var onLoad = function( url, success )
                        {
                                // Mark this script as loaded.
                                uniqueScripts[ url ] = 1;

                                // Get the list of callback checks waiting for this file.
                                var waitingInfo = waitingList[ url ];
                                delete waitingList[ url ];

                                // Check all callbacks waiting for this file.
                                for ( var i = 0 ; i < waitingInfo.length ; i++ )
                                        waitingInfo[ i ]( url, success );
                        };

                        var loadScript = function( url )
                        {
                                if ( uniqueScripts[ url ] )
                                {
                                        checkLoaded( url, true );
                                        return;
                                }

                                var waitingInfo = waitingList[ url ] || ( waitingList[ url ] = [] );
                                waitingInfo.push( checkLoaded );

                                // Load it only for the first request.
                                if ( waitingInfo.length > 1 )
                                        return;

                                // Create the <script> element.
                                var script = new CKEDITOR.dom.element( 'script' );
                                script.setAttributes( {
                                        type : 'text/javascript',
                                        src : url } );

                                if ( callback )
                                {
                                        if ( CKEDITOR.env.ie )
                                        {
                                                // FIXME: For IE, we are not able to return false on error (like 404).

                                                /** @ignore */
                                                script.$.onreadystatechange = function ()
                                                {
                                                        if ( script.$.readyState == 'loaded' || script.$.readyState == 'complete' )
                                                        {
                                                                script.$.onreadystatechange = null;
                                                                onLoad( url, true );
                                                        }
                                                };
                                        }
                                        else
                                        {
                                                /** @ignore */
                                                script.$.onload = function()
                                                {
                                                        // Some browsers, such as Safari, may call the onLoad function
                                                        // immediately. Which will break the loading sequence. (#3661)
                                                        setTimeout( function() { onLoad( url, true ); }, 0 );
                                                };

                                                // FIXME: Opera and Safari will not fire onerror.

                                                /** @ignore */
                                                script.$.onerror = function()
                                                {
                                                        onLoad( url, false );
                                                };
                                        }
                                }

                                // Append it to <head>.
                                script.appendTo( CKEDITOR.document.getHead() );

                                CKEDITOR.fire( 'download', url );               // @Packager.RemoveLine
                        };

                        showBusy && CKEDITOR.document.getDocumentElement().setStyle( 'cursor', 'wait' );
                        for ( var i = 0 ; i < scriptCount ; i++ )
                        {
                                loadScript( scriptUrl[ i ] );
                        }
                }
        };
})();