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/*
* Copyright (C) 2019, Matthias Sohn <matthias.sohn@sap.com>
* 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.internal.storage.file;
import java.io.File;
import java.io.IOException;
import java.io.RandomAccessFile;
import org.eclipse.jgit.lib.AnyObjectId;
import org.eclipse.jgit.lib.ObjectId;
class PackFileSnapshot extends FileSnapshot {
private static final ObjectId MISSING_CHECKSUM = ObjectId.zeroId();
/**
* Record a snapshot for a specific packfile path.
* <p>
* This method should be invoked before the packfile is accessed.
*
* @param path
* the path to later remember. The path's current status
* information is saved.
* @return the snapshot.
*/
public static PackFileSnapshot save(File path) {
return new PackFileSnapshot(path);
}
private AnyObjectId checksum = MISSING_CHECKSUM;
private boolean wasChecksumChanged;
PackFileSnapshot(File packFile) {
super(packFile);
}
void setChecksum(AnyObjectId checksum) {
this.checksum = checksum;
}
/** {@inheritDoc} */
@Override
public boolean isModified(File packFile) {
if (!super.isModified(packFile)) {
return false;
}
if (wasSizeChanged() || wasFileKeyChanged()
|| !wasLastModifiedRacilyClean()) {
return true;
}
return isChecksumChanged(packFile);
}
boolean isChecksumChanged(File packFile) {
return wasChecksumChanged = checksum != MISSING_CHECKSUM
&& !checksum.equals(readChecksum(packFile));
}
private AnyObjectId readChecksum(File packFile) {
try (RandomAccessFile fd = new RandomAccessFile(packFile, "r")) { //$NON-NLS-1$
fd.seek(fd.length() - 20);
final byte[] buf = new byte[20];
fd.readFully(buf, 0, 20);
return ObjectId.fromRaw(buf);
} catch (IOException e) {
return MISSING_CHECKSUM;
}
}
boolean wasChecksumChanged() {
return wasChecksumChanged;
}
@SuppressWarnings("nls")
@Override
public String toString() {
return "PackFileSnapshot [checksum=" + checksum + ", "
+ super.toString() + "]";
}
}
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