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This OSGi bundle wraps ${pkgArtifactId} ${pkgVersion} jar file.
/*
* Copyright 2011 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.Callback;
import com.google.gwt.core.client.ScriptInjector;
import com.google.gwt.core.client.impl.AsyncFragmentLoader.HttpDownloadFailure;
/**
* A download strategy that uses a JSONP style script tag mechanism. and is
* therefore cross site compatible. Note that if this strategy is used, the
* deferred fragments must be wrapped in a callback called runAsyncCallbackX()
* where X is the fragment number.
*
* This is the default strategy for the CrossSiteIframeLinker.
*/
public class ScriptTagLoadingStrategy extends LoadingStrategyBase {
/**
* Uses a JSONP style script tag mechanism to download the code.
*/
// Visible for testing.
public static class ScriptTagDownloadStrategy implements DownloadStrategy {
@Override
public void tryDownload(final RequestData request) {
setAsyncCallback(request.getFragment(), request);
ScriptInjector.fromUrl(request.getUrl()).setRemoveTag(true).setCallback(
new Callback() {
@Override
public void onFailure(Exception reason) {
cleanup(request);
}
@Override
public void onSuccess(Void result) {
cleanup(request);
}
}).inject();
}
}
private static void asyncCallback(RequestData request, String code) {
boolean firstTimeCalled = clearAsyncCallback(request.getFragment());
if (firstTimeCalled) {
request.tryInstall(code);
}
}
private static void cleanup(RequestData request) {
boolean neverCalled = clearAsyncCallback(request.getFragment());
if (neverCalled) {
request.onLoadError(new HttpDownloadFailure(request.getUrl(), 404,
"Script Tag Failure - no status available"), true);
}
}
/**
* Returns true if the callback existed.
*/
private static native boolean clearAsyncCallback(int fragment) /*-{
if (!__gwtModuleFunction['runAsyncCallback' + fragment]) {
return false;
}
delete __gwtModuleFunction['runAsyncCallback' + fragment];
return true;
}-*/;
private static native void setAsyncCallback(int fragment, RequestData request) /*-{
__gwtModuleFunction['runAsyncCallback' + fragment] = $entry(function(code, instance) {
@com.google.gwt.core.client.impl.ScriptTagLoadingStrategy::asyncCallback(Lcom/google/gwt/core/client/impl/LoadingStrategyBase$RequestData;Ljava/lang/String;)(
request, code);
});
}-*/;
public ScriptTagLoadingStrategy() {
super(new ScriptTagDownloadStrategy());
}
}