org.eclipse.jgit.storage.dfs.DfsOutputStream Maven / Gradle / Ivy
/*
* Copyright (C) 2011, 2012 Google Inc. and others.
* 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.
*
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* 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
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package org.eclipse.jgit.storage.dfs;
import java.io.IOException;
import java.io.OutputStream;
import java.nio.ByteBuffer;
import org.eclipse.jgit.storage.pack.PackExt;
/**
* Output stream to create a file on the DFS.
*
* @see DfsObjDatabase#writeFile(DfsPackDescription, PackExt)
*/
public abstract class DfsOutputStream extends OutputStream {
/**
* Get the recommended alignment for writing.
*
* Starting a write at multiples of the blockSize is more efficient than
* starting a write at any other position. If 0 or -1 the channel does not
* have any specific block size recommendation.
*
* Channels should not recommend large block sizes. Sizes up to 1-4 MiB may
* be reasonable, but sizes above that may be horribly inefficient.
*
* @return recommended alignment size for randomly positioned reads. Does
* not need to be a power of 2.
*/
public int blockSize() {
return 0;
}
@Override
public void write(int b) throws IOException {
write(new byte[] { (byte) b });
}
@Override
public abstract void write(byte[] buf, int off, int len) throws IOException;
/**
* Read back a portion of already written data.
*
* The writing position of the output stream is not affected by a read.
*
* @param position
* offset to read from.
* @param buf
* buffer to populate. Up to {@code buf.remaining()} bytes will
* be read from {@code position}.
* @return number of bytes actually read.
* @throws IOException
* reading is not supported, or the read cannot be performed due
* to DFS errors.
*/
public abstract int read(long position, ByteBuffer buf) throws IOException;
}