/*
* Copyright 2014 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.dev;
import com.google.gwt.core.ext.TreeLogger;
import com.google.gwt.dev.cfg.PropertyCombinations.PermutationDescription;
import com.google.gwt.dev.util.CompilerVersion;
import com.google.gwt.thirdparty.guava.common.annotations.VisibleForTesting;
import com.google.gwt.thirdparty.guava.common.cache.Cache;
import com.google.gwt.thirdparty.guava.common.cache.CacheBuilder;
import com.google.gwt.thirdparty.guava.common.util.concurrent.Futures;
import com.google.gwt.thirdparty.guava.common.util.concurrent.MoreExecutors;
import com.google.gwt.util.tools.Utility;
import com.google.gwt.util.tools.shared.Md5Utils;
import com.google.gwt.util.tools.shared.StringUtils;
import java.io.BufferedInputStream;
import java.io.BufferedOutputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.util.LinkedHashMap;
import java.util.Map;
import java.util.concurrent.Callable;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.Future;
import java.util.concurrent.ThreadPoolExecutor;
import java.util.concurrent.TimeUnit;
/**
* Manages caching of MinimalRebuildCache instances.
* <p>
* Changes are immediately performed in memory and are asynchronously persisted to disk in original
* request order.
*/
public class MinimalRebuildCacheManager {
private static final int MEMORY_CACHE_COUNT_LIMIT = 3;
private static final String REBUILD_CACHE_PREFIX = "gwt-rebuildCache";
private final ExecutorService executorService =
MoreExecutors.getExitingExecutorService((ThreadPoolExecutor) Executors.newFixedThreadPool(1));
private final TreeLogger logger;
private final File minimalRebuildCacheDir;
private final Cache<String, MinimalRebuildCache> minimalRebuildCachesByName =
CacheBuilder.newBuilder().maximumSize(MEMORY_CACHE_COUNT_LIMIT).build();
private final Map<String, String> options = new LinkedHashMap<>();
public MinimalRebuildCacheManager(
TreeLogger logger, File baseCacheDir, Map<String, String> options) {
this.logger = logger;
this.options.putAll(options);
if (baseCacheDir != null) {
minimalRebuildCacheDir = new File(baseCacheDir, REBUILD_CACHE_PREFIX);
minimalRebuildCacheDir.mkdir();
} else {
minimalRebuildCacheDir = null;
}
}
/**
* Synchronously delete all in memory caches managed here and all on disk in the managed folder.
*/
public synchronized void deleteCaches() {
syncDeleteMemoryCaches();
if (haveCacheDir()) {
Futures.getUnchecked(enqueueAsyncDeleteDiskCaches());
}
}
/**
* Synchronously return the MinimalRebuildCache specific to the given module and binding
* properties.
* <p>
* If no cache is found in memory then it will be synchronously loaded from disk.
* <p>
* If it is still not found a new empty cache will be returned.
*/
public synchronized MinimalRebuildCache getCache(String moduleName,
PermutationDescription permutationDescription) {
String cacheName =
computeMinimalRebuildCacheName(moduleName, permutationDescription);
MinimalRebuildCache minimalRebuildCache = minimalRebuildCachesByName.getIfPresent(cacheName);
// If there's no cache already in memory, try to load a cache from disk.
if (minimalRebuildCache == null && haveCacheDir()) {
// Might return null.
minimalRebuildCache = syncReadDiskCache(moduleName, permutationDescription);
if (minimalRebuildCache != null) {
minimalRebuildCachesByName.put(cacheName, minimalRebuildCache);
}
}
// If there's still no cache loaded, just create a blank one.
if (minimalRebuildCache == null) {
minimalRebuildCache = new MinimalRebuildCache();
minimalRebuildCachesByName.put(cacheName, minimalRebuildCache);
return minimalRebuildCache;
}
// Return a copy.
MinimalRebuildCache mutableMinimalRebuildCache = new MinimalRebuildCache();
mutableMinimalRebuildCache.copyFrom(minimalRebuildCache);
return mutableMinimalRebuildCache;
}
/**
* Stores a MinimalRebuildCache specific to the given module and binding properties.
* <p>
* A copy of the cache will be lazily persisted to disk as well.
*/
public synchronized void putCache(String moduleName,
PermutationDescription permutationDescription,
MinimalRebuildCache knownGoodMinimalRebuildCache) {
syncPutMemoryCache(moduleName, permutationDescription, knownGoodMinimalRebuildCache);
if (haveCacheDir()) {
enqueueAsyncWriteDiskCache(moduleName, permutationDescription, knownGoodMinimalRebuildCache);
}
}
/**
* Enqueue to asynchronously delete all on disk caches in the managed cache folder.
*/
@VisibleForTesting
synchronized Future<Void> enqueueAsyncDeleteDiskCaches() {
return executorService.submit(new Callable<Void>() {
@Override
public Void call() {
for (File cacheFile : minimalRebuildCacheDir.listFiles()) {
if (!cacheFile.delete()) {
logger.log(TreeLogger.WARN, "Couldn't delete " + cacheFile);
}
}
return null;
}
});
}
/**
* Enqueue to asynchronously find, read and return the MinimalRebuildCache unique to this module
* and binding properties combination in the managed cache folder.
*/
@VisibleForTesting
synchronized Future<MinimalRebuildCache> enqueueAsyncReadDiskCache(final String moduleName,
final PermutationDescription permutationDescription) {
return executorService.submit(new Callable<MinimalRebuildCache>() {
@Override
public MinimalRebuildCache call() {
// Find the cache file unique to this module, binding properties and working directory.
File minimalRebuildCacheFile =
computeMinimalRebuildCacheFile(moduleName, permutationDescription);
// If the file exists.
if (minimalRebuildCacheFile.exists()) {
ObjectInputStream objectInputStream = null;
// Try to read it.
try {
objectInputStream = new ObjectInputStream(
new BufferedInputStream(new FileInputStream(minimalRebuildCacheFile)));
return (MinimalRebuildCache) objectInputStream.readObject();
} catch (IOException e) {
logger.log(TreeLogger.WARN,
"Unable to read the rebuild cache in " + minimalRebuildCacheFile + ".");
Utility.close(objectInputStream);
minimalRebuildCacheFile.delete();
} catch (ClassNotFoundException e) {
logger.log(TreeLogger.WARN,
"Unable to read the rebuild cache in " + minimalRebuildCacheFile + ".");
Utility.close(objectInputStream);
minimalRebuildCacheFile.delete();
} finally {
Utility.close(objectInputStream);
}
}
return null;
}
});
}
/**
* Enqueue to asynchronously write the provided MinimalRebuildCache to disk.
* <p>
* Persisted caches are uniquely named based on the compiler version, current module name, binding
* properties and the location where the JVM was launched.
* <p>
* Care is taken to completely and successfully write a new cache (to a different location on
* disk) before replacing the old cache (at the regular location on disk).
* <p>
* Write requests will occur in the order requested and will queue up if requests are made faster
* than they can be completed.
*/
@VisibleForTesting
synchronized Future<Void> enqueueAsyncWriteDiskCache(final String moduleName,
final PermutationDescription permutationDescription,
final MinimalRebuildCache minimalRebuildCache) {
return executorService.submit(new Callable<Void>() {
@Override
public Void call() {
File oldMinimalRebuildCacheFile =
computeMinimalRebuildCacheFile(moduleName, permutationDescription);
File newMinimalRebuildCacheFile =
new File(oldMinimalRebuildCacheFile.getAbsoluteFile() + ".new");
// Ensure the cache folder exists.
oldMinimalRebuildCacheFile.getParentFile().mkdirs();
// Write the new cache to disk.
ObjectOutputStream objectOutputStream = null;
try {
objectOutputStream = new ObjectOutputStream(
new BufferedOutputStream(new FileOutputStream(newMinimalRebuildCacheFile)));
objectOutputStream.writeObject(minimalRebuildCache);
Utility.close(objectOutputStream);
// Replace the old cache file with the new one.
oldMinimalRebuildCacheFile.delete();
newMinimalRebuildCacheFile.renameTo(oldMinimalRebuildCacheFile);
} catch (IOException e) {
logger.log(TreeLogger.WARN,
"Unable to update the cache in " + oldMinimalRebuildCacheFile + ".");
newMinimalRebuildCacheFile.delete();
} finally {
if (objectOutputStream != null) {
Utility.close(objectOutputStream);
}
}
return null;
}
});
}
/**
* For testing only. Stops accepting any new tasks and waits for current tasks to complete.
*/
@VisibleForTesting
boolean shutdown() throws InterruptedException {
executorService.shutdown();
return executorService.awaitTermination(30, TimeUnit.SECONDS);
}
/**
* Find, read and return the MinimalRebuildCache unique to this module, binding properties and
* working directory.
*/
@VisibleForTesting
synchronized MinimalRebuildCache syncReadDiskCache(String moduleName,
PermutationDescription permutationDescription) {
return Futures.getUnchecked(enqueueAsyncReadDiskCache(moduleName, permutationDescription));
}
private File computeMinimalRebuildCacheFile(String moduleName,
PermutationDescription permutationDescription) {
return new File(minimalRebuildCacheDir,
computeMinimalRebuildCacheName(moduleName, permutationDescription));
}
private String computeMinimalRebuildCacheName(String moduleName,
PermutationDescription permutationDescription) {
String currentWorkingDirectory = System.getProperty("user.dir");
String compilerVersionHash = CompilerVersion.getHash();
String permutationDescriptionString = permutationDescription.toString();
String optionsDescriptionString = " Options [";
String separator = "";
for (Map.Entry entry : options.entrySet()) {
optionsDescriptionString +=
String.format("%s%s = %s", separator, entry.getKey(), entry.getValue());
separator = ",";
}
optionsDescriptionString += "]";
String consistentHash = StringUtils.toHexString(Md5Utils.getMd5Digest((
compilerVersionHash
+ moduleName
+ currentWorkingDirectory
+ permutationDescriptionString
+ optionsDescriptionString)
.getBytes()));
return REBUILD_CACHE_PREFIX + "-" + consistentHash;
}
private boolean haveCacheDir() {
return minimalRebuildCacheDir != null && minimalRebuildCacheDir.isDirectory();
}
private void syncDeleteMemoryCaches() {
minimalRebuildCachesByName.invalidateAll();
}
private void syncPutMemoryCache(String moduleName, PermutationDescription permutationDescription,
MinimalRebuildCache knownGoodMinimalRebuildCache) {
String cacheName = computeMinimalRebuildCacheName(moduleName, permutationDescription);
minimalRebuildCachesByName.put(cacheName, knownGoodMinimalRebuildCache);
}
}