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- /*******************************************************************************
- * Copyright (c) 2012 Contributors.
- * All rights reserved.
- * This program and the accompanying materials are made available
- * under the terms of the Eclipse Public License v1.0
- * which accompanies this distribution and is available at
- * http://eclipse.org/legal/epl-v10.html
- *
- * Contributors:
- * Lyor Goldstein (vmware) add support for weaved class being re-defined
- *******************************************************************************/
-
- package org.aspectj.weaver.tools.cache;
-
- import java.io.File;
- import java.util.ArrayList;
- import java.util.Collections;
- import java.util.List;
- import java.util.Map;
- import java.util.concurrent.BlockingQueue;
- import java.util.concurrent.ExecutorService;
- import java.util.concurrent.Executors;
- import java.util.concurrent.Future;
- import java.util.concurrent.LinkedBlockingQueue;
-
- import org.aspectj.util.FileUtil;
- import org.aspectj.util.LangUtil;
- import org.aspectj.weaver.tools.Trace;
- import org.aspectj.weaver.tools.TraceFactory;
-
- /**
- * Uses a background thread to do the actual I/O and for caching "persistence"
- * so that the caching works faster on repeated activations of the application.
- * The class maintains an in-memory cache, and uses a queue of {@link AsyncCommand}s
- * to signal to a background thread various actions required to "synchronize"
- * the in-memory cache with the persisted copy. Whenever there is a cache miss
- * from the {@link #get(CachedClassReference)} call, the weaver issues a
- * {@link #put(CachedClassEntry)} call. This call has 2 side-effects:</BR>
- * <UL>
- * <LI>
- * The in-memory cache is updated so that subsequent calls to {@link #get(CachedClassReference)}
- * will not return the mapped value.
- * </LI>
- *
- * <LI>
- * An "update index" {@link AsyncCommand} is posted to the background
- * thread so that the newly mapped value will be persisted (eventually)
- * </LI>
- * </UL>
- * The actual persistence is implemented by the <U>concrete</U> classes
- */
- public abstract class AsynchronousFileCacheBacking extends AbstractIndexedFileCacheBacking {
- private static final BlockingQueue<AsyncCommand> commandsQ= new LinkedBlockingQueue<>();
- private static final ExecutorService execService=Executors.newSingleThreadExecutor();
- private static Future<?> commandsRunner;
-
- protected final Map<String, IndexEntry> index, exposedIndex;
- protected final Map<String, byte[]> bytesMap, exposedBytes;
-
- protected AsynchronousFileCacheBacking (File cacheDir) {
- super(cacheDir);
-
- index = readIndex(cacheDir, getIndexFile());
- exposedIndex = Collections.unmodifiableMap(index);
- bytesMap = readClassBytes(index, cacheDir);
- exposedBytes = Collections.unmodifiableMap(bytesMap);
- }
-
- @Override
- protected Map<String, IndexEntry> getIndex() {
- return index;
- }
-
- public CachedClassEntry get(CachedClassReference ref, byte[] originalBytes) {
- String key=ref.getKey();
- final IndexEntry indexEntry;
- synchronized(index) {
- if ((indexEntry=index.get(key)) == null) {
- return null;
- }
- }
-
- if (crc(originalBytes) != indexEntry.crcClass) {
- if ((logger != null) && logger.isTraceEnabled()) {
- logger.debug("get(" + getCacheDirectory() + ") mismatched original class bytes CRC for " + key);
- }
-
- remove(key);
- return null;
- }
-
- if (indexEntry.ignored) {
- return new CachedClassEntry(ref, WeavedClassCache.ZERO_BYTES, CachedClassEntry.EntryType.IGNORED);
- }
-
- final byte[] bytes;
- synchronized(bytesMap) {
- /*
- * NOTE: we assume that keys represent classes so if we have their
- * bytes they will not be re-created
- */
- if ((bytes=bytesMap.remove(key)) == null) {
- return null;
- }
- }
-
- if (indexEntry.generated) {
- return new CachedClassEntry(ref, bytes, CachedClassEntry.EntryType.GENERATED);
- } else {
- return new CachedClassEntry(ref, bytes, CachedClassEntry.EntryType.WEAVED);
- }
- }
-
- public void put(CachedClassEntry entry, byte[] originalBytes) {
- String key=entry.getKey();
- byte[] bytes=entry.isIgnored() ? null : entry.getBytes();
- synchronized(index) {
- IndexEntry indexEntry=index.get(key);
- if (indexEntry != null) {
- return;
- }
-
- /*
- * Note: we do not cache the class bytes - only send them to
- * be saved. The assumption is that the 'put' call was invoked
- * because 'get' failed to return any bytes. And since we assume
- * that each class bytes are required only once, there is no
- * need to cache them
- */
- indexEntry = createIndexEntry(entry, originalBytes);
- index.put(key, indexEntry);
- }
-
- if (!postCacheCommand(new InsertCommand(this, key, bytes))) {
- if ((logger != null) && logger.isTraceEnabled()) {
- logger.error("put(" + getCacheDirectory() + ") Failed to post insert command for " + key);
- }
- }
-
- if ((logger != null) && logger.isTraceEnabled()) {
- logger.debug("put(" + getCacheDirectory() + ")[" + key + "] inserted");
- }
- }
-
- public void remove(CachedClassReference ref) {
- remove(ref.getKey());
- }
-
- protected IndexEntry remove (String key) {
- IndexEntry entry;
- synchronized(index) {
- entry = index.remove(key);
- }
-
- synchronized(bytesMap) {
- bytesMap.remove(key);
- }
-
- if (!postCacheCommand(new RemoveCommand(this, key))) {
- if ((logger != null) && logger.isTraceEnabled()) {
- logger.error("remove(" + getCacheDirectory() + ") Failed to post remove command for " + key);
- }
- }
-
- if (entry != null) {
- if (!key.equals(entry.key)) {
- if ((logger != null) && logger.isTraceEnabled()) {
- logger.error("remove(" + getCacheDirectory() + ") Mismatched keys: " + key + " / " + entry.key);
- }
- } else if ((logger != null) && logger.isTraceEnabled()) {
- logger.debug("remove(" + getCacheDirectory() + ")[" + key + "] removed");
- }
- }
-
- return entry;
- }
-
- public List<IndexEntry> getIndexEntries () {
- synchronized(index) {
- if (index.isEmpty()) {
- return Collections.emptyList();
- } else {
- return new ArrayList<>(index.values());
- }
- }
- }
-
- public Map<String, IndexEntry> getIndexMap () {
- return exposedIndex;
- }
-
- public Map<String, byte[]> getBytesMap () {
- return exposedBytes;
- }
-
- public void clear() {
- synchronized(index) {
- index.clear();
- }
-
- if (!postCacheCommand(new ClearCommand(this))) {
- if ((logger != null) && logger.isTraceEnabled()) {
- logger.error("Failed to post clear command for " + getIndexFile());
- }
- }
- }
-
- protected void executeCommand (AsyncCommand cmd) throws Exception {
- if (cmd instanceof ClearCommand) {
- executeClearCommand();
- } else if (cmd instanceof UpdateIndexCommand) {
- executeUpdateIndexCommand();
- } else if (cmd instanceof InsertCommand) {
- executeInsertCommand((InsertCommand) cmd);
- } else if (cmd instanceof RemoveCommand) {
- executeRemoveCommand((RemoveCommand) cmd);
- } else {
- throw new UnsupportedOperationException("Unknown command: " + cmd);
- }
- }
-
- protected void executeClearCommand () throws Exception {
- FileUtil.deleteContents(getIndexFile());
- FileUtil.deleteContents(getCacheDirectory());
- }
-
- protected void executeUpdateIndexCommand () throws Exception {
- writeIndex(getIndexFile(), getIndexEntries());
- }
-
- protected void executeInsertCommand (InsertCommand cmd) throws Exception {
- writeIndex(getIndexFile(), getIndexEntries());
-
- byte[] bytes=cmd.getClassBytes();
- if (bytes != null) {
- writeClassBytes(cmd.getKey(), bytes);
- }
- }
-
- protected void executeRemoveCommand (RemoveCommand cmd) throws Exception {
- Exception err=null;
- try {
- removeClassBytes(cmd.getKey());
- } catch(Exception e) {
- err = e;
- }
-
- writeIndex(getIndexFile(), getIndexEntries());
-
- if (err != null) {
- throw err; // check if the class bytes remove had any problems
- }
- }
-
- /**
- * Helper for {@link #executeRemoveCommand(RemoveCommand)}
- * @param key The key representing the class whose bytes are to be removed
- * @throws Exception if failed to remove class bytes
- */
- protected abstract void removeClassBytes (String key) throws Exception;
-
- protected abstract Map<String, byte[]> readClassBytes (Map<String,IndexEntry> indexMap, File cacheDir);
-
- @Override
- public String toString() {
- return getClass().getSimpleName() + "[" + String.valueOf(getCacheDirectory()) + "]";
- }
-
- protected static final <T extends AsynchronousFileCacheBacking> T createBacking (
- File cacheDir, AsynchronousFileCacheBackingCreator<T> creator) {
- final Trace trace=TraceFactory.getTraceFactory().getTrace(AsynchronousFileCacheBacking.class);
- if (!cacheDir.exists()) {
- if (!cacheDir.mkdirs()) {
- if ((trace != null) && trace.isTraceEnabled()) {
- trace.error("Unable to create cache directory at " + cacheDir.getAbsolutePath());
- }
- return null;
- }
- }
-
- if (!cacheDir.canWrite()) {
- if ((trace != null) && trace.isTraceEnabled()) {
- trace.error("Cache directory is not writable at " + cacheDir.getAbsolutePath());
- }
- return null;
- }
-
- // start the service (if needed) only if successfully create the backing instance
- T backing=creator.create(cacheDir);
- synchronized(execService) {
- if (commandsRunner == null) {
- commandsRunner = execService.submit(new Runnable() {
- @SuppressWarnings("synthetic-access")
- public void run() {
- for ( ; ; ) {
- try {
- AsyncCommand cmd=commandsQ.take();
- try {
- AsynchronousFileCacheBacking cache=cmd.getCache();
- cache.executeCommand(cmd);
- } catch(Exception e) {
- if ((trace != null) && trace.isTraceEnabled()) {
- trace.error("Failed (" + e.getClass().getSimpleName() + ")"
- + " to execute " + cmd + ": " + e.getMessage(), e);
- }
- }
- } catch(InterruptedException e) {
- if ((trace != null) && trace.isTraceEnabled()) {
- trace.warn("Interrupted");
- }
- Thread.currentThread().interrupt();
- break;
- }
- }
- }
- });
- }
- }
-
- // fire-up an update-index command in case index was changed by the constructor
- if (!postCacheCommand(new UpdateIndexCommand(backing))) {
- if ((trace != null) && trace.isTraceEnabled()) {
- trace.warn("Failed to offer update index command to " + cacheDir.getAbsolutePath());
- }
- }
-
- return backing;
- }
-
- public static final boolean postCacheCommand (AsyncCommand cmd) {
- return commandsQ.offer(cmd);
- }
-
- public interface AsynchronousFileCacheBackingCreator<T extends AsynchronousFileCacheBacking> {
- T create (File cacheDir);
- }
- /**
- * Represents an asynchronous command that can be sent to the
- * {@link AsynchronousFileCacheBacking} instance to be executed
- * on it <U>asynchronously</U>
- */
- public interface AsyncCommand {
- /**
- * @return The {@link AsynchronousFileCacheBacking} on which
- * this command is supposed to be executed
- * @see AsynchronousFileCacheBacking#executeCommand(AsyncCommand)
- */
- AsynchronousFileCacheBacking getCache ();
- }
-
- public static abstract class AbstractCommand implements AsyncCommand {
- private final AsynchronousFileCacheBacking cache;
- protected AbstractCommand (AsynchronousFileCacheBacking backing) {
- if ((cache=backing) == null) {
- throw new IllegalStateException("No backing cache specified");
- }
- }
-
- public final AsynchronousFileCacheBacking getCache () {
- return cache;
- }
-
- @Override
- public String toString() {
- return getClass().getSimpleName() + "[" + getCache() + "]";
- }
- }
-
- public static class ClearCommand extends AbstractCommand {
- public ClearCommand (AsynchronousFileCacheBacking cache) {
- super(cache);
- }
- }
-
- public static class UpdateIndexCommand extends AbstractCommand {
- public UpdateIndexCommand (AsynchronousFileCacheBacking cache) {
- super(cache);
- }
- }
-
- /**
- * Base class for {@link AbstractCommand}s that refer to a cache key
- */
- public static abstract class KeyedCommand extends AbstractCommand {
- private final String key;
- protected KeyedCommand (AsynchronousFileCacheBacking cache, String keyValue) {
- super(cache);
-
- if (LangUtil.isEmpty(keyValue)) {
- throw new IllegalStateException("No key value");
- }
-
- key = keyValue;
- }
-
- public final String getKey () {
- return key;
- }
-
- @Override
- public String toString() {
- return super.toString() + "[" + getKey() + "]";
- }
- }
-
- public static class RemoveCommand extends KeyedCommand {
- public RemoveCommand (AsynchronousFileCacheBacking cache, String keyValue) {
- super(cache, keyValue);
- }
- }
-
- public static class InsertCommand extends KeyedCommand {
- private final byte[] bytes;
-
- public InsertCommand (AsynchronousFileCacheBacking cache, String keyValue, byte[] classBytes) {
- super(cache, keyValue);
- bytes = classBytes;
- }
-
- public final byte[] getClassBytes () {
- return bytes;
- }
- }
- }
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