/*
* Copyright (C) 2010, Google Inc.
* Copyright (C) 2009, Robin Rosenberg
* and other copyright owners as documented in the project's IP log.
*
* This program and the accompanying materials are made available
* under the terms of the Eclipse Distribution License v1.0 which
* accompanies this distribution, is reproduced below, and is
* available at http://www.eclipse.org/org/documents/edl-v10.php
*
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or
* without modification, are permitted provided that the following
* conditions are met:
*
* - Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
*
* - Redistributions in binary form must reproduce the above
* copyright notice, this list of conditions and the following
* disclaimer in the documentation and/or other materials provided
* with the distribution.
*
* - Neither the name of the Eclipse Foundation, Inc. nor the
* names of its contributors may be used to endorse or promote
* products derived from this software without specific prior
* written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND
* CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
* INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
* CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
* STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
* ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
package org.eclipse.jgit.storage.file;
import java.io.File;
import java.io.IOException;
import org.eclipse.jgit.lib.Constants;
import org.eclipse.jgit.lib.ObjectId;
import org.eclipse.jgit.lib.RefRename;
import org.eclipse.jgit.lib.RefUpdate;
import org.eclipse.jgit.lib.RefUpdate.Result;
import org.eclipse.jgit.revwalk.RevWalk;
import org.eclipse.jgit.util.FileUtils;
/**
* Rename any reference stored by {@link RefDirectory}.
* <p>
* This class works by first renaming the source reference to a temporary name,
* then renaming the temporary name to the final destination reference.
* <p>
* This strategy permits switching a reference like {@code refs/heads/foo},
* which is a file, to {@code refs/heads/foo/bar}, which is stored inside a
* directory that happens to match the source name.
*/
class RefDirectoryRename extends RefRename {
private final RefDirectory refdb;
/**
* The value of the source reference at the start of the rename.
* <p>
* At the end of the rename the destination reference must have this same
* value, otherwise we have a concurrent update and the rename must fail
* without making any changes.
*/
private ObjectId objId;
/** True if HEAD must be moved to the destination reference. */
private boolean updateHEAD;
/** A reference we backup {@link #objId} into during the rename. */
private RefDirectoryUpdate tmp;
RefDirectoryRename(RefDirectoryUpdate src, RefDirectoryUpdate dst) {
super(src, dst);
refdb = src.getRefDatabase();
}
@Override
protected Result doRename() throws IOException {
if (source.getRef().isSymbolic())
return Result.IO_FAILURE; // not supported
objId = source.getOldObjectId();
updateHEAD = needToUpdateHEAD();
tmp = refdb.newTemporaryUpdate();
final RevWalk rw = new RevWalk(refdb.getRepository());
try {
// First backup the source so its never unreachable.
tmp.setNewObjectId(objId);
tmp.setForceUpdate(true);
tmp.disableRefLog();
switch (tmp.update(rw)) {
case NEW:
case FORCED:
case NO_CHANGE:
break;
default:
return tmp.getResult();
}
// Save the source's log under the temporary name, we must do
// this before we delete the source, otherwise we lose the log.
if (!renameLog(source, tmp))
return Result.IO_FAILURE;
// If HEAD has to be updated, link it now to destination.
// We have to link before we delete, otherwise the delete
// fails because its the current branch.
RefUpdate dst = destination;
if (updateHEAD) {
if (!linkHEAD(destination)) {
renameLog(tmp, source);
return Result.LOCK_FAILURE;
}
// Replace the update operation so HEAD will log the rename.
dst = refdb.newUpdate(Constants.HEAD, false);
dst.setRefLogIdent(destination.getRefLogIdent());
dst.setRefLogMessage(destination.getRefLogMessage(), false);
}
// Delete the source name so its path is free for replacement.
source.setExpectedOldObjectId(objId);
source.setForceUpdate(true);
source.disableRefLog();
if (source.delete(rw) != Result.FORCED) {
renameLog(tmp, source);
if (updateHEAD)
linkHEAD(source);
return source.getResult();
}
// Move the log to the destination.
if (!renameLog(tmp, destination)) {
renameLog(tmp, source);
source.setExpectedOldObjectId(ObjectId.zeroId());
source.setNewObjectId(objId);
source.update(rw);
if (updateHEAD)
linkHEAD(source);
return Result.IO_FAILURE;
}
// Create the destination, logging the rename during the creation.
dst.setExpectedOldObjectId(ObjectId.zeroId());
dst.setNewObjectId(objId);
if (dst.update(rw) != Result.NEW) {
// If we didn't create the destination we have to undo
// our work. Put the log back and restore source.
if (renameLog(destination, tmp))
renameLog(tmp, source);
source.setExpectedOldObjectId(ObjectId.zeroId());
source.setNewObjectId(objId);
source.update(rw);
if (updateHEAD)
linkHEAD(source);
return dst.getResult();
}
return Result.RENAMED;
} finally {
// Always try to free the temporary name.
try {
refdb.delete(tmp);
} catch (IOException err) {
FileUtils.delete(refdb.fileFor(tmp.getName()));
}
rw.release();
}
}
private boolean renameLog(RefUpdate src, RefUpdate dst) {
File srcLog = refdb.getLogWriter().logFor(src.getName());
File dstLog = refdb.getLogWriter().logFor(dst.getName());
if (!srcLog.exists())
return true;
if (!rename(srcLog, dstLog))
return false;
try {
final int levels = RefDirectory.levelsIn(src.getName()) - 2;
RefDirectory.delete(srcLog, levels);
return true;
} catch (IOException e) {
rename(dstLog, srcLog);
return false;
}
}
private static boolean rename(File src, File dst) {
if (src.renameTo(dst))
return true;
File dir = dst.getParentFile();
if ((dir.exists() || !dir.mkdirs()) && !dir.isDirectory())
return false;
return src.renameTo(dst);
}
private boolean linkHEAD(RefUpdate target) {
try {
RefUpdate u = refdb.newUpdate(Constants.HEAD, false);
u.disableRefLog();
switch (u.link(target.getName())) {
case NEW:
case FORCED:
case NO_CHANGE:
return true;
default:
return false;
}
} catch (IOException e) {
return false;
}
}
}