/*==========================================================================*\
| $Id: FileBasedLockManager.java,v 1.1 2011/05/13 19:46:57 aallowat Exp $
|*-------------------------------------------------------------------------*|
| Copyright (C) 2011 Virginia Tech
|
| This file is part of Web-CAT.
|
| Web-CAT is free software; you can redistribute it and/or modify
| it under the terms of the GNU Affero General Public License as published
| by the Free Software Foundation; either version 3 of the License, or
| (at your option) any later version.
|
| Web-CAT is distributed in the hope that it will be useful,
| but WITHOUT ANY WARRANTY; without even the implied warranty of
| MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
| GNU General Public License for more details.
|
| You should have received a copy of the GNU Affero General Public License
| along with Web-CAT; if not, see <http://www.gnu.org/licenses/>.
\*==========================================================================*/
package org.webcat.core.webdav;
import com.bradmcevoy.http.LockInfo;
import com.bradmcevoy.http.LockResult;
import com.bradmcevoy.http.LockTimeout;
import com.bradmcevoy.http.LockToken;
import com.bradmcevoy.http.LockableResource;
import com.bradmcevoy.http.LockResult.FailureReason;
import com.bradmcevoy.http.exceptions.NotAuthorizedException;
import com.ettrema.http.fs.LockManager;
import java.io.File;
import java.util.Date;
import java.util.HashMap;
import java.util.Map;
import java.util.UUID;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
//-------------------------------------------------------------------------
/**
* TODO real description
*
* @author Tony Allevato
* @author Last changed by $Author: aallowat $
* @version $Revision: 1.1 $, $Date: 2011/05/13 19:46:57 $
*/
public class FileBasedLockManager implements LockManager
{
//~ Constructors ..........................................................
// ----------------------------------------------------------
public FileBasedLockManager()
{
locksByPath = new HashMap<DAVPath, CurrentLock>();
locksByToken = new HashMap<String, CurrentLock>();
}
//~ Methods ...............................................................
// ----------------------------------------------------------
public synchronized LockResult lock(LockTimeout timeout, LockInfo lockInfo,
LockableResource r)
{
if (!(r instanceof AbstractFSResource))
{
return LockResult.failed(FailureReason.PRECONDITION_FAILED);
}
AbstractFSResource resource = (AbstractFSResource) r;
LockToken currentLock = currentLock(resource);
if (currentLock != null)
{
return LockResult.failed(LockResult.FailureReason.ALREADY_LOCKED);
}
LockToken newToken = new LockToken(
UUID.randomUUID().toString(), lockInfo, timeout);
CurrentLock newLock = new CurrentLock(
resource.path(), newToken, lockInfo.lockedByUser);
locksByPath.put(resource.path(), newLock);
locksByToken.put(newToken.tokenId, newLock);
return LockResult.success(newToken);
}
// ----------------------------------------------------------
public synchronized LockResult refresh(String tokenId,
LockableResource resource)
{
CurrentLock curLock = locksByToken.get(tokenId);
if (curLock == null)
{
log.debug("can't refresh because no lock");
return LockResult.failed(FailureReason.PRECONDITION_FAILED);
}
else
{
curLock.token.setFrom(new Date());
return LockResult.success(curLock.token);
}
}
// ----------------------------------------------------------
public synchronized void unlock(String tokenId, LockableResource r)
throws NotAuthorizedException
{
if (!(r instanceof AbstractFSResource))
{
return;
}
AbstractFSResource resource = (AbstractFSResource) r;
LockToken lockToken = currentLock(resource);
if (lockToken == null)
{
log.debug("not locked");
return;
}
if (lockToken.tokenId.equals(tokenId))
{
removeLock(lockToken);
}
else
{
throw new NotAuthorizedException(resource);
}
}
// ----------------------------------------------------------
public LockToken getCurrentToken(LockableResource r)
{
if (!(r instanceof AbstractFSResource))
{
return null;
}
AbstractFSResource resource = (AbstractFSResource) r;
CurrentLock lock = locksByPath.get(resource.path());
if (lock == null)
{
return null;
}
LockToken token = new LockToken();
token.info = new LockInfo(
LockInfo.LockScope.EXCLUSIVE,
LockInfo.LockType.WRITE,
lock.lockedByUser,
LockInfo.LockDepth.ZERO);
token.info.lockedByUser = lock.lockedByUser;
token.timeout = lock.token.timeout;
token.tokenId = lock.token.tokenId;
return token;
}
// ----------------------------------------------------------
/**
* Looks for a lock token for the specified resource in the lock table and
* returns it if it was found and has not yet expired.
*
* @param resource the resource
* @return the lock token for the resource, or null if the lock did not
* exist or had expired
*/
private LockToken currentLock(AbstractFSResource resource)
{
CurrentLock curLock = locksByPath.get(resource.path());
if (curLock == null)
{
return null;
}
LockToken token = curLock.token;
if (token.isExpired())
{
removeLock(token);
return null;
}
else
{
return token;
}
}
// ----------------------------------------------------------
/**
* Removes the lock with the specified {@code LockToken} from the manager's
* lock tables.
*
* @param token the lock token to remove
*/
private void removeLock(LockToken token)
{
log.debug("removeLock: " + token.tokenId);
CurrentLock currentLock = locksByToken.get(token.tokenId);
if (currentLock != null)
{
locksByPath.remove(currentLock.path);
locksByToken.remove(currentLock.token.tokenId);
}
else
{
log.warn("removeLock: Couldn't find lock: " + token.tokenId);
}
}
//~ Inner classes .........................................................
// ----------------------------------------------------------
private static class CurrentLock
{
//~ Constructors ......................................................
// ----------------------------------------------------------
public CurrentLock(DAVPath path, LockToken token, String lockedByUser)
{
this.path = path;
this.token = token;
this.lockedByUser = lockedByUser;
}
//~ Static/instance variables .........................................
public final DAVPath path;
public final LockToken token;
public final String lockedByUser;
}
//~ Static/instance variables .............................................
private Map<DAVPath, CurrentLock> locksByPath;
private Map<String, CurrentLock> locksByToken;
private static final Logger log = LoggerFactory.getLogger(
FileBasedLockManager.class);
}