X-Git-Url: http://git.ithinksw.org/extjs.git/blobdiff_plain/6a7e4474cba9d8be4b2ec445e10f1691f7277c50..530ef4b6c5b943cfa68b779d11cf7de29aa878bf:/src/ext-core/src/core/Loader.js

diff --git a/src/ext-core/src/core/Loader.js b/src/ext-core/src/core/Loader.js
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+++ b/src/ext-core/src/core/Loader.js
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+/*!
+ * Ext JS Library 3.2.1
+ * Copyright(c) 2006-2010 Ext JS, Inc.
+ * licensing@extjs.com
+ * http://www.extjs.com/license
+ */
+/**
+ * @class Ext.Loader
+ * @singleton
+ * Simple class to help load JavaScript files on demand
+ */
+Ext.Loader = Ext.apply({}, {
+    /**
+     * Loads a given set of .js files. Calls the callback function when all files have been loaded
+     * Set preserveOrder to true to ensure non-parallel loading of files if load order is important
+     * @param {Array} fileList Array of all files to load
+     * @param {Function} callback Callback to call after all files have been loaded
+     * @param {Object} scope The scope to call the callback in
+     * @param {Boolean} preserveOrder True to make files load in serial, one after the other (defaults to false)
+     */
+    load: function(fileList, callback, scope, preserveOrder) {
+        var scope       = scope || this,
+            head        = document.getElementsByTagName("head")[0],
+            fragment    = document.createDocumentFragment(),
+            numFiles    = fileList.length,
+            loadedFiles = 0,
+            me          = this;
+        
+        /**
+         * Loads a particular file from the fileList by index. This is used when preserving order
+         */
+        var loadFileIndex = function(index) {
+            head.appendChild(
+                me.buildScriptTag(fileList[index], onFileLoaded)
+            );
+        };
+        
+        /**
+         * Callback function which is called after each file has been loaded. This calls the callback
+         * passed to load once the final file in the fileList has been loaded
+         */
+        var onFileLoaded = function() {
+            loadedFiles ++;
+            
+            //if this was the last file, call the callback, otherwise load the next file
+            if (numFiles == loadedFiles && typeof callback == 'function') {
+                callback.call(scope);
+            } else {
+                if (preserveOrder === true) {
+                    loadFileIndex(loadedFiles);
+                }
+            }
+        };
+        
+        if (preserveOrder === true) {
+            loadFileIndex.call(this, 0);
+        } else {
+            //load each file (most browsers will do this in parallel)
+            Ext.each(fileList, function(file, index) {
+                fragment.appendChild(
+                    this.buildScriptTag(file, onFileLoaded)
+                );  
+            }, this);
+            
+            head.appendChild(fragment);
+        }
+    },
+    
+    /**
+     * @private
+     * Creates and returns a script tag, but does not place it into the document. If a callback function
+     * is passed, this is called when the script has been loaded
+     * @param {String} filename The name of the file to create a script tag for
+     * @param {Function} callback Optional callback, which is called when the script has been loaded
+     * @return {Element} The new script ta
+     */
+    buildScriptTag: function(filename, callback) {
+        var script  = document.createElement('script');
+        script.type = "text/javascript";
+        script.src  = filename;
+        
+        //IE has a different way of handling <script> loads, so we need to check for it here
+        if (script.readyState) {
+            script.onreadystatechange = function() {
+                if (script.readyState == "loaded" || script.readyState == "complete") {
+                    script.onreadystatechange = null;
+                    callback();
+                }
+            };
+        } else {
+            script.onload = callback;
+        }    
+        
+        return script;
+    }
+});
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