| /* |
| * Copyright 2009 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. |
| */ |
| package com.google.gwt.core.client.impl; |
| |
| import com.google.gwt.core.client.impl.AsyncFragmentLoader.HttpDownloadFailure; |
| import com.google.gwt.core.client.impl.LoadingStrategyBase.RequestData; |
| |
| /** |
| * A download strategy that uses XHRs and iss therefore not cross site compatible. |
| * |
| * This is the default strategy for the IframeLinker. |
| */ |
| public class XhrLoadingStrategy extends LoadingStrategyBase { |
| |
| /** |
| * Uses XHR's to download the code. |
| */ |
| public static class XhrDownloadStrategy implements DownloadStrategy { |
| @Override |
| public native void tryDownload(final RequestData request)/*-{ |
| var xhr = new $wnd.XMLHttpRequest() |
| xhr.open("GET", request.@RequestData::getUrl()()); |
| xhr.onreadystatechange = function() { |
| if (xhr.readyState == 4) { |
| // Clearing onreadystatechange otherwise it may cause memory leak (e.g. in IE8). |
| xhr.onreadystatechange = function() {}; // Clear callback |
| @XhrLoadingStrategy::onLoad(*)(request, xhr.status, xhr.statusText, xhr.responseText); |
| } |
| }; |
| xhr.send(null); |
| }-*/; |
| } |
| |
| /** |
| * Some UA's like Safari will have a "0" status code when loading from file: |
| * URLs. Additionally, the "0" status code is used sometimes if the server |
| * does not respond, e.g. if there is a connection refused. |
| */ |
| private static final int HTTP_STATUS_NON_HTTP = 0; |
| |
| private static final int HTTP_STATUS_OK = 200; |
| |
| @SuppressWarnings("unused") // Called via JSNI |
| private static void onLoad(RequestData request, int status, String statusText, String response) { |
| if ((status == HTTP_STATUS_OK || status == HTTP_STATUS_NON_HTTP) |
| && response != null |
| && response.length() != 0) { |
| request.tryInstall(response); |
| } else { |
| // If the download fails |
| request.onLoadError(new HttpDownloadFailure(request.getUrl(), status, statusText), true); |
| } |
| } |
| |
| public XhrLoadingStrategy() { |
| super(new XhrDownloadStrategy()); |
| } |
| |
| } |