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The implementation module of Ehcache 3
/*
* Copyright Terracotta, 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 org.ehcache.impl.persistence;
import org.ehcache.CachePersistenceException;
import org.ehcache.core.spi.service.LocalPersistenceService;
import org.ehcache.impl.config.persistence.DefaultPersistenceConfiguration;
import org.ehcache.spi.service.MaintainableService;
import org.ehcache.spi.service.Service;
import org.ehcache.spi.service.ServiceProvider;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.RandomAccessFile;
import java.nio.channels.FileLock;
import java.nio.channels.OverlappingFileLockException;
import static org.ehcache.impl.persistence.FileUtils.createLocationIfRequiredAndVerify;
import static org.ehcache.impl.persistence.FileUtils.recursiveDeleteDirectoryContent;
import static org.ehcache.impl.persistence.FileUtils.safeIdentifier;
import static org.ehcache.impl.persistence.FileUtils.tryRecursiveDelete;
import static org.ehcache.impl.persistence.FileUtils.validateName;
/**
* Implements the local persistence service that provides individual sub-spaces for different
* services.
*/
public class DefaultLocalPersistenceService implements LocalPersistenceService {
private static final Logger LOGGER = LoggerFactory.getLogger(DefaultLocalPersistenceService.class);
private final File rootDirectory;
private final File lockFile;
private FileLock lock;
private RandomAccessFile rw;
private boolean started;
/**
* Creates a new service instance using the provided configuration.
*
* @param persistenceConfiguration the configuration to use
*/
public DefaultLocalPersistenceService(final DefaultPersistenceConfiguration persistenceConfiguration) {
if(persistenceConfiguration != null) {
rootDirectory = persistenceConfiguration.getRootDirectory();
} else {
throw new NullPointerException("DefaultPersistenceConfiguration cannot be null");
}
lockFile = new File(rootDirectory, ".lock");
}
/**
* {@inheritDoc}
*/
@Override
public synchronized void start(final ServiceProvider serviceProvider) {
internalStart();
}
@Override
public synchronized void startForMaintenance(ServiceProvider serviceProvider, MaintenanceScope maintenanceScope) {
internalStart();
}
private void internalStart() {
if (!started) {
createLocationIfRequiredAndVerify(rootDirectory);
try {
rw = new RandomAccessFile(lockFile, "rw");
} catch (FileNotFoundException e) {
// should not happen normally since we checked that everything is fine right above
throw new RuntimeException(e);
}
try {
lock = rw.getChannel().tryLock();
} catch (OverlappingFileLockException e) {
throw new RuntimeException("Persistence directory already locked by this process: " + rootDirectory.getAbsolutePath(), e);
} catch (Exception e) {
try {
rw.close();
} catch (IOException e1) {
// ignore silently
}
throw new RuntimeException("Persistence directory couldn't be locked: " + rootDirectory.getAbsolutePath(), e);
}
if (lock == null) {
throw new RuntimeException("Persistence directory already locked by another process: " + rootDirectory.getAbsolutePath());
}
started = true;
LOGGER.debug("RootDirectory Locked");
}
}
/**
* {@inheritDoc}
*/
@Override
public synchronized void stop() {
if (started) {
try {
lock.release();
// Closing RandomAccessFile so that files gets deleted on windows and
// org.ehcache.internal.persistence.DefaultLocalPersistenceServiceTest.testLocksDirectoryAndUnlocks()
// passes on windows
rw.close();
if (!lockFile.delete()) {
LOGGER.debug("Lock file was not deleted {}.", lockFile.getPath());
}
} catch (IOException e) {
throw new RuntimeException("Couldn't unlock rootDir: " + rootDirectory.getAbsolutePath(), e);
}
started = false;
LOGGER.debug("RootDirectory Unlocked");
}
}
File getLockFile() {
return lockFile;
}
/**
* {@inheritDoc}
*/
@Override
public SafeSpaceIdentifier createSafeSpaceIdentifier(String owner, String identifier) {
validateName(owner);
SafeSpace ss = createSafeSpaceLogical(owner, identifier);
for (File parent = ss.directory.getParentFile(); parent != null; parent = parent.getParentFile()) {
if (rootDirectory.equals(parent)) {
return new DefaultSafeSpaceIdentifier(ss);
}
}
throw new IllegalArgumentException("Attempted to access file outside the persistence path");
}
/**
* {@inheritDoc}
*/
@Override
public void createSafeSpace(SafeSpaceIdentifier safeSpaceId) throws CachePersistenceException {
if (safeSpaceId == null || !(safeSpaceId instanceof DefaultSafeSpaceIdentifier)) {
// this cannot happen..if identifier created before creating physical space..
throw new AssertionError("Invalid safe space identifier. Identifier not created");
}
SafeSpace ss = ((DefaultSafeSpaceIdentifier) safeSpaceId).safeSpace;
FileUtils.create(ss.directory.getParentFile());
FileUtils.create(ss.directory);
}
/**
* {@inheritDoc}
*/
@Override
public void destroySafeSpace(SafeSpaceIdentifier safeSpaceId, boolean verbose) {
if (safeSpaceId == null || !(safeSpaceId instanceof DefaultSafeSpaceIdentifier)) {
// this cannot happen..if identifier created before creating/destroying physical space..
throw new AssertionError("Invalid safe space identifier. Identifier not created");
}
SafeSpace ss = ((DefaultSafeSpaceIdentifier) safeSpaceId).safeSpace;
destroy(ss, verbose);
}
/**
* {@inheritDoc}
*/
public void destroyAll(String owner) {
File ownerDirectory = new File(rootDirectory, owner);
boolean cleared = true;
if (ownerDirectory.exists() && ownerDirectory.isDirectory()) {
cleared = false;
if (recursiveDeleteDirectoryContent(ownerDirectory)) {
LOGGER.debug("Destroyed all file based persistence contexts owned by {}", owner);
cleared = ownerDirectory.delete();
}
}
if (!cleared) {
LOGGER.warn("Could not delete all file based persistence contexts owned by {}", owner);
}
}
private void destroy(SafeSpace ss, boolean verbose) {
if (verbose) {
LOGGER.debug("Destroying file based persistence context for {}", ss.identifier);
}
if (ss.directory.exists() && !tryRecursiveDelete(ss.directory)) {
if (verbose) {
LOGGER.warn("Could not delete directory for context {}", ss.identifier);
}
}
}
private SafeSpace createSafeSpaceLogical(String owner, String identifier) {
File ownerDirectory = new File(rootDirectory, owner);
File directory = new File(ownerDirectory, safeIdentifier(identifier));
return new SafeSpace(identifier, directory);
}
private static final class SafeSpace {
private final String identifier;
private final File directory;
private SafeSpace(String identifier, File directory) {
this.directory = directory;
this.identifier = identifier;
}
}
private static final class DefaultSafeSpaceIdentifier implements SafeSpaceIdentifier {
private final SafeSpace safeSpace;
private DefaultSafeSpaceIdentifier(SafeSpace safeSpace) {
this.safeSpace = safeSpace;
}
@Override
public String toString() {
return safeSpace.identifier;
}
@Override
public File getRoot() {
return safeSpace.directory;
}
}
}