/*
* Copyright (C) 2014 Red Hat, Inc. and/or its affiliates.
*
* 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 org.jboss.errai.offline.linker;
import java.util.Arrays;
import java.util.Collection;
import java.util.Date;
import java.util.Map;
import java.util.Set;
import com.google.common.collect.ArrayListMultimap;
import com.google.common.collect.Multimap;
import com.google.gwt.core.ext.Linker;
import com.google.gwt.core.ext.LinkerContext;
import com.google.gwt.core.ext.TreeLogger;
import com.google.gwt.core.ext.UnableToCompleteException;
import com.google.gwt.core.ext.linker.AbstractLinker;
import com.google.gwt.core.ext.linker.Artifact;
import com.google.gwt.core.ext.linker.ArtifactSet;
import com.google.gwt.core.ext.linker.EmittedArtifact;
import com.google.gwt.core.ext.linker.LinkerOrder;
import com.google.gwt.core.ext.linker.LinkerOrder.Order;
import com.google.gwt.core.ext.linker.Shardable;
import com.google.gwt.core.ext.linker.Transferable;
import com.google.gwt.core.ext.linker.impl.SelectionInformation;
import com.google.gwt.dev.util.collect.HashSet;
/**
* Linker that generates permutation specific HTML5 Cache Manifest files for
* Errai applications.
*
* This linker is based on <a
* href="https://code.google.com/p/google-web-toolkit/source/browse/
* trunk/dev/core/src/
* com/google/gwt/core/linker/SimpleAppCacheLinker.java?r=10136
* ">SimpleAppCacheLinker</a>.
*
* <p>
* To use:
* <ol>
* <li>Define the linker in your gwt.xml module descriptor:
*
* <pre>
* {@code <define-linker name="offline" class="org.jboss.errai.offline.linker.DefaultCacheManifestLinker" />}
* {@code <add-linker name="offline" />}
* </pre>
*
* </li>
*
* <li>Add {@code manifest="YOURMODULENAME/errai.appcache"} to the
* {@code <html>} tag in your host page e.g.,
* {@code <html manifest="mymodule/errai.appcache">} <br>
* <br>
* </li>
*
* <li>Add a mime-mapping to your web.xml file (you can skip this step if you
* deploy the errai-javaee-all.jar as part of your application):
*
* <pre>
* {@code <mime-mapping>
* <extension>manifest</extension>
* <mime-type>text/cache-manifest</mime-type>
* </mime-mapping>
* }
* </pre>
*
* </li>
*
* <li>Make sure the errai-common.jar file is deployed as part of your
* application. It contains a servlet that will provide the correct user-agent
* specific manifest file in response to requests to
* YOURMODULENAME/errai.appcache</li>
* </ol>
*
* <p>
* To obtain manifests that contain other files in addition to those generated
* by this linker, create a class that inherits from this one and overrides
* {@code otherCachedFiles()}, and use it as a linker instead:
*
* <pre>
* {@code @Shardable}
* {@code @LinkerOrder(Order.POST)}
* public class MyCacheManifestLinker extends DefaultCacheManifestLinker {
* {@code @Override}
* protected String[] otherCachedFiles() {
* return new String[] {"/my-app/index.html","/my-app/css/application.css"};
* }
* }
* </pre>
*
* @author Christian Sadilek <csadilek@redhat.com>
*/
@Shardable
@LinkerOrder(Order.POST)
public class DefaultCacheManifestLinker extends AbstractLinker {
private static final String MANIFEST = "appcache.manifest";
@Transferable
private class PermutationCacheManifestArtifact extends Artifact<PermutationCacheManifestArtifact> {
private static final long serialVersionUID = 1L;
private final Set<String> cachedFiles = new HashSet<String>();
private final String name;
private final Map<String, String> props;
public PermutationCacheManifestArtifact(Class<? extends Linker> linker, String name, Map<String, String> props) {
super(linker);
this.name = name;
this.props = props;
}
@Override
public int hashCode() {
return cachedFiles.hashCode();
}
@Override
protected int compareToComparableArtifact(PermutationCacheManifestArtifact o) {
return name.compareTo(o.name);
}
@Override
protected Class<PermutationCacheManifestArtifact> getComparableArtifactType() {
return PermutationCacheManifestArtifact.class;
}
public void addCachedFile(String file) {
cachedFiles.add(file);
}
}
@Override
public String getDescription() {
return "to generate cache manifest files";
}
@Override
public ArtifactSet link(TreeLogger logger, LinkerContext context, ArtifactSet artifacts, boolean onePermutation)
throws UnableToCompleteException {
final ArtifactSet toReturn = new ArtifactSet(artifacts);
if (toReturn.find(SelectionInformation.class).isEmpty()) {
logger.log(TreeLogger.INFO, "devmode: generating empty " + MANIFEST);
toReturn.add(emitString(logger, "# Empty in DevMode\n", "dev." + MANIFEST));
}
else if (onePermutation) {
// Create an artifact representing the cache manifest for the current
// permutation
toReturn.add(createPermutationCacheManifestArtifact(context, logger, artifacts));
}
else {
// Group permutations per user agent
final Multimap<String, PermutationCacheManifestArtifact> permutations = ArrayListMultimap.create();
for (final PermutationCacheManifestArtifact pcma : artifacts.find(PermutationCacheManifestArtifact.class)) {
permutations.put(pcma.props.get("user.agent"), pcma);
}
for (final String userAgent : permutations.keySet()) {
// Create a cache manifest file for every user agent
toReturn.add(emitUserAgentCacheManifestFile(userAgent, permutations.get(userAgent), artifacts, logger));
}
logger.log(TreeLogger.INFO,
"Make sure you have the following attribute added to your host page's <html> tag: <html manifest=\""
+ context.getModuleFunctionName() + "/" + MANIFEST + "\">");
}
return toReturn;
}
/**
* Override this method to include additional files in the manifest.
*/
protected String[] otherCachedFiles() {
return null;
}
/**
* Creates the cache manifest artifact specific to the current permutation.
*
* @param context
* the linker environment
* @param logger
* the tree logger to record to
* @param artifacts
* {@code null} in case no permutation specific artifacts exist
*/
private Artifact<?> createPermutationCacheManifestArtifact(LinkerContext context, TreeLogger logger,
ArtifactSet artifacts) {
final SelectionInformation si = artifacts.find(SelectionInformation.class).first();
final PermutationCacheManifestArtifact cacheArtifact = new PermutationCacheManifestArtifact(this.getClass(),
si.getStrongName(), si.getPropMap());
for (final Artifact<?> artifact : artifacts) {
if (artifact instanceof EmittedArtifact) {
final EmittedArtifact ea = (EmittedArtifact) artifact;
final String pathName = ea.getPartialPath();
if (shouldBeCached(pathName)) {
cacheArtifact.addCachedFile(pathName);
}
}
}
return cacheArtifact;
}
/**
* Emits the cache manifest file for the user agent represented by the
* provided artifacts.
*
* @param userAgent
* the user agent name
* @param artifacts
* the user agent specific cache manifest artifacts
* @param globalArtifacts
* all artifacts known to this linker
* @param logger
* the tree logger to record to
* @return a synthetic artifact representing the cache manifest file for the
* user agent
*
* @throws UnableToCompleteException
*/
private Artifact<?> emitUserAgentCacheManifestFile(String userAgent,
Collection<PermutationCacheManifestArtifact> artifacts, ArtifactSet globalArtifacts, TreeLogger logger)
throws UnableToCompleteException {
// Add static external resources
final StringBuilder staticResoucesSb = new StringBuilder();
final String[] cacheExtraFiles = getCacheExtraFiles();
for (int i = 0; i < cacheExtraFiles.length; i++) {
staticResoucesSb.append(cacheExtraFiles[i]);
staticResoucesSb.append("\n");
}
// Add generated resources
final Set<String> cacheableGeneratedResources = new HashSet<String>();
// Add permutation independent resources
if (globalArtifacts != null) {
for (final Artifact<?> a : globalArtifacts) {
if (a instanceof EmittedArtifact) {
final EmittedArtifact ea = (EmittedArtifact) a;
final String pathName = ea.getPartialPath();
if (shouldBeCached(pathName) && !isPermutationSpecific(globalArtifacts, pathName)) {
cacheableGeneratedResources.add(pathName);
}
}
}
}
// Add permutation specific resources
if (artifacts != null) {
for (final PermutationCacheManifestArtifact artifact : artifacts) {
for (final String cachedFile : artifact.cachedFiles) {
cacheableGeneratedResources.add(cachedFile);
}
}
}
// Build manifest
final StringBuilder sb = new StringBuilder();
sb.append("CACHE MANIFEST\n");
// we have to generate this unique id because the resources can change but
// the hashed cache.html files can remain the same.
sb.append("# Unique id #" + (new Date()).getTime() + "." + Math.random() + "\n");
sb.append("\n");
sb.append("CACHE:\n");
sb.append("# Static app files\n");
sb.append(staticResoucesSb.toString());
sb.append("\n# Generated permutation specific app files");
for (final String resource : cacheableGeneratedResources) {
sb.append("\n");
sb.append(resource);
}
sb.append("\n\n");
sb.append("# All other resources require the user to be online.\n");
sb.append("NETWORK:\n");
sb.append("*\n");
// Create the user agent specific manifest as a new artifact and return it
return emitString(logger, sb.toString(), userAgent + "." + MANIFEST);
}
/**
* Obtains the extra files to include in the manifest. Ensures the returned
* array is not null.
*/
private String[] getCacheExtraFiles() {
final String[] cacheExtraFiles = otherCachedFiles();
return cacheExtraFiles == null ? new String[0] : Arrays.copyOf(cacheExtraFiles, cacheExtraFiles.length);
}
private Set<String> permutationFiles;
/**
* Checks whether the provided file is specific to a permutation.
*
* @param artifacts
* all artifacts passed to this linker
* @param file
* the file to check
* @return true if the file is specific to a permutation, otherwise false.
*
*/
private boolean isPermutationSpecific(ArtifactSet artifacts, String file) {
if (permutationFiles == null) {
permutationFiles = new HashSet<String>();
for (final PermutationCacheManifestArtifact pcma : artifacts.find(PermutationCacheManifestArtifact.class)) {
permutationFiles.addAll(pcma.cachedFiles);
}
}
return permutationFiles.contains(file);
}
/**
* Checks whether or not the provided file should be cached.
*
* @param file
* the file to check
* @return true if the file is cacheable and should therefore be listed in the
* cache manifest file, otherwise false.
*/
private boolean shouldBeCached(String file) {
return !(file.endsWith("symbolMap") || file.endsWith(".xml.gz") || file.endsWith("rpc.log")
|| file.endsWith("gwt.rpc") || file.endsWith("manifest.txt") || file.startsWith("rpcPolicyManifest")
|| file.startsWith("deferredjs") || file.startsWith("hosted") || file.startsWith("junit") );
}
}