com.google.gwt.dev.javac.UnitCacheSingleton Maven / Gradle / Ivy
/*
* 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.dev.javac;
import com.google.gwt.core.ext.TreeLogger;
import com.google.gwt.core.ext.UnableToCompleteException;
import java.io.File;
/**
* Lazily creates a singleton cache for {@link CompilationUnit} instances.
*/
public class UnitCacheSingleton {
public static final String GWT_PERSISTENTUNITCACHE = "gwt.persistentunitcache";
private static final String GWT_PERSISTENTUNITCACHEDIR = "gwt.persistentunitcachedir";
/**
* The API must be enabled explicitly for persistent caching to be live.
*/
private static final String configPropertyValue = System.getProperty(GWT_PERSISTENTUNITCACHE,
"true");
private static final boolean usePersistent = configPropertyValue.length() == 0
|| Boolean.parseBoolean(configPropertyValue);
private static UnitCache instance = null;
/**
* If a cache exists, asks it to clear its contents.
*/
public static synchronized void clearCache() throws UnableToCompleteException {
if (instance == null) {
return;
}
instance.clear();
}
/**
* If the cache is enabled, instantiates the cache and begins loading units
* into memory in a background thread. If the cache is not enabled, it clears
* out any old cached files.
*
* Only one instance of the cache is instantiated. If a previously created
* cache exists, the previous instance is returned.
*
* The specified cache dir parameter is optional.
*/
public static synchronized UnitCache get(TreeLogger logger, File specifiedCacheDir) {
return get(logger, specifiedCacheDir, null);
}
/**
* If the cache is enabled, instantiates the cache and begins loading units
* into memory in a background thread. If the cache is not enabled, it clears
* out any old cached files.
*
* Only one instance of the cache is instantiated. If a previously created
* cache exists, the previous instance is returned.
*
* Both specified and fallback cache dir parameters are optional.
*/
public static synchronized UnitCache get(TreeLogger logger, File specifiedCacheDir,
File fallbackCacheDir) {
assert logger != null;
if (instance == null) {
String propertyCachePath = System.getProperty(GWT_PERSISTENTUNITCACHEDIR);
File propertyCacheDir = propertyCachePath != null ? new File(propertyCachePath) : null;
if (usePersistent) {
File actualCacheDir = null;
// Pick the highest priority cache dir that is available.
if (specifiedCacheDir != null) {
actualCacheDir = specifiedCacheDir;
} else if (propertyCacheDir != null) {
actualCacheDir = propertyCacheDir;
} else if (fallbackCacheDir != null) {
actualCacheDir = fallbackCacheDir;
} else {
logger.log(TreeLogger.TRACE, "Persistent caching disabled - no directory specified.\n"
+ "To enable persistent unit caching use -Dgwt.persistentunitcachedir=
");
}
if (actualCacheDir != null) {
try {
return instance = new PersistentUnitCache(logger, actualCacheDir);
} catch (UnableToCompleteException ignored) {
}
}
}
// Fallback - use in-memory only cache.
instance = new MemoryUnitCache();
}
return instance;
}
}