| /* |
| * 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. |
| * <p> |
| * Only one instance of the cache is instantiated. If a previously created |
| * cache exists, the previous instance is returned. |
| * <p> |
| * 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. |
| * <p> |
| * Only one instance of the cache is instantiated. If a previously created |
| * cache exists, the previous instance is returned. |
| * <p> |
| * 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=<dir>"); |
| } |
| |
| if (actualCacheDir != null) { |
| try { |
| return instance = new PersistentUnitCache(logger, actualCacheDir); |
| } catch (UnableToCompleteException ignored) { |
| } |
| } |
| } |
| // Fallback - use in-memory only cache. |
| instance = new MemoryUnitCache(); |
| } |
| return instance; |
| } |
| } |