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* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you 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
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*/
package org.apache.shindig.gadgets.js;
import com.google.common.annotations.VisibleForTesting;
import com.google.common.collect.ImmutableList;
import com.google.common.collect.Lists;
import com.google.inject.Inject;
import com.google.inject.Provider;
import org.apache.shindig.gadgets.GadgetContext;
import org.apache.shindig.gadgets.features.FeatureRegistry;
import org.apache.shindig.gadgets.features.FeatureRegistry.FeatureBundle;
import org.apache.shindig.gadgets.features.FeatureRegistry.LookupResult;
import org.apache.shindig.gadgets.features.FeatureRegistryProvider;
import org.apache.shindig.gadgets.uri.JsUriManager.JsUri;
import java.util.List;
public class DeferJsProcessor extends BaseSurfaceJsProcessor implements JsProcessor {
@VisibleForTesting
static final String FEATURE_NAME = "deferjs";
private static final String FUNCTION_NAME = "deferJs";
@Inject
public DeferJsProcessor(FeatureRegistryProvider featureRegistryProvider,
Provider<GadgetContext> context) {
super(featureRegistryProvider, context);
}
public boolean process(JsRequest jsRequest, JsResponseBuilder builder) throws JsException {
JsUri jsUri = jsRequest.getJsUri();
ImmutableList.Builder<JsContent> resp = ImmutableList.builder();
FeatureRegistry featureRegistry = getFeatureRegistry(jsUri);
boolean needDefers = false;
if (jsUri.isJsload()) {
// append all exports for deferred symbols
List<FeatureBundle> bundles = getSupportDeferBundles(featureRegistry, jsRequest);
for (FeatureBundle bundle : bundles) {
needDefers |= appendDeferJsStatements(resp, jsRequest.getJsUri(), bundle);
}
}
// TODO: Instead of clearing, do a replacement of feature impl with defer stubs.
// Clearing has an effect of ignoring previous processors work.
if (needDefers) {
builder.appendAllJs(getSurfaceJsContents(featureRegistry, FEATURE_NAME));
}
builder.appendAllJs(resp.build());
return true;
}
private boolean appendDeferJsStatements(ImmutableList.Builder<JsContent> builder,
JsUri jsUri, FeatureBundle bundle) {
List<String> exports = getExports(bundle, jsUri);
if (!exports.isEmpty()) {
StringBuilder sb = new StringBuilder();
for (Input input : generateInputs(exports)) {
sb.append(toDeferStatement(input));
}
builder.add(JsContent.fromFeature(sb.toString(), "[generated-symbol-exports]",
bundle, null));
return true;
}
return false;
}
private String toDeferStatement(Input input) {
StringBuilder result = new StringBuilder();
// Local namespace.
if (input.namespace != null) {
result.append(FUNCTION_NAME).append("('").append(input.namespace).append("',[");
for (int i = 0; i < input.properties.size(); i++) {
String prop = input.properties.get(i);
if (i > 0) result.append(',');
result.append('\'').append(prop).append('\'');
}
result.append("]);");
// Global/window namespace.
} else {
for (String prop : input.properties) {
result.append(FUNCTION_NAME).append("('").append(prop).append("');");
}
}
return result.toString();
}
private List<FeatureBundle> getSupportDeferBundles(FeatureRegistry registry, JsRequest jsRequest) {
List<FeatureBundle> result = Lists.newArrayList();
LookupResult lookup = registry.getFeatureResources(context.get(),
jsRequest.getNewFeatures(), null, false);
for (FeatureBundle bundle : lookup.getBundles()) {
if (bundle.isSupportDefer()) {
result.add(bundle);
}
}
return result;
}
}