org.eclipse.jgit/src/org/eclipse/jgit/internal/storage/pack/PackOutputStream.java - sop/jgit - Git at Google

 /*
  * Copyright (C) 2008-2009, Google Inc.
  * Copyright (C) 2008, Marek Zawirski <marek.zawirski@gmail.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.pack;

 import static org.eclipse.jgit.lib.Constants.OBJ_OFS_DELTA;
 import static org.eclipse.jgit.lib.Constants.OBJ_REF_DELTA;
 import static org.eclipse.jgit.lib.Constants.PACK_SIGNATURE;

 import java.io.IOException;
 import java.io.OutputStream;
 import java.security.MessageDigest;

 import org.eclipse.jgit.internal.JGitText;
 import org.eclipse.jgit.lib.Constants;
 import org.eclipse.jgit.lib.ProgressMonitor;
 import org.eclipse.jgit.util.NB;

 /** Custom output stream to support {@link PackWriter}. */
 public final class PackOutputStream extends OutputStream {
 	private static final int BYTES_TO_WRITE_BEFORE_CANCEL_CHECK = 128 * 1024;

 	private final ProgressMonitor writeMonitor;

 	private final OutputStream out;

 	private final PackWriter packWriter;

 	private final MessageDigest md = Constants.newMessageDigest();

 	private long count;

 	private final byte[] headerBuffer = new byte[32];

 	private final byte[] copyBuffer = new byte[64 << 10];

 	private long checkCancelAt;

 	private boolean ofsDelta;

 	/**
 	 * Initialize a pack output stream.
 	 * <p>
 	 * This constructor is exposed to support debugging the JGit library only.
 	 * Application or storage level code should not create a PackOutputStream,
 	 * instead use {@link PackWriter}, and let the writer create the stream.
 	 *
 	 * @param writeMonitor
 	 *            monitor to update on object output progress.
 	 * @param out
 	 *            target stream to receive all object contents.
 	 * @param pw
 	 *            packer that is going to perform the output.
 	 */
 	public PackOutputStream(final ProgressMonitor writeMonitor,
 			final OutputStream out, final PackWriter pw) {
 		this.writeMonitor = writeMonitor;
 		this.out = out;
 		this.packWriter = pw;
 		this.checkCancelAt = BYTES_TO_WRITE_BEFORE_CANCEL_CHECK;
 	}

 	@Override
 	public final void write(final int b) throws IOException {
 		count++;
 		out.write(b);
 		md.update((byte) b);
 	}

 	@Override
 	public final void write(final byte[] b, int off, int len)
 			throws IOException {
 		while (0 < len) {
 			final int n = Math.min(len, BYTES_TO_WRITE_BEFORE_CANCEL_CHECK);
 			count += n;

 			if (checkCancelAt <= count) {
 				if (writeMonitor.isCancelled()) {
 					throw new IOException(
 							JGitText.get().packingCancelledDuringObjectsWriting);
 				}
 				checkCancelAt = count + BYTES_TO_WRITE_BEFORE_CANCEL_CHECK;
 			}

 			out.write(b, off, n);
 			md.update(b, off, n);

 			off += n;
 			len -= n;
 		}
 	}

 	@Override
 	public void flush() throws IOException {
 		out.flush();
 	}

 	final void writeFileHeader(int version, long objectCount)
 			throws IOException {
 		System.arraycopy(PACK_SIGNATURE, 0, headerBuffer, 0, 4);
 		NB.encodeInt32(headerBuffer, 4, version);
 		NB.encodeInt32(headerBuffer, 8, (int) objectCount);
 		write(headerBuffer, 0, 12);
 		ofsDelta = packWriter.isDeltaBaseAsOffset();
 	}

 	/**
 	 * Write one object.
 	 *
 	 * If the object was already written, this method does nothing and returns
 	 * quickly. This case occurs whenever an object was written out of order in
 	 * order to ensure the delta base occurred before the object that needs it.
 	 *
 	 * @param otp
 	 *            the object to write.
 	 * @throws IOException
 	 *             the object cannot be read from the object reader, or the
 	 *             output stream is no longer accepting output. Caller must
 	 *             examine the type of exception and possibly its message to
 	 *             distinguish between these cases.
 	 */
 	public final void writeObject(ObjectToPack otp) throws IOException {
 		packWriter.writeObject(this, otp);
 	}

 	/**
 	 * Commits the object header onto the stream.
 	 * <p>
 	 * Once the header has been written, the object representation must be fully
 	 * output, or packing must abort abnormally.
 	 *
 	 * @param otp
 	 *            the object to pack. Header information is obtained.
 	 * @param rawLength
 	 *            number of bytes of the inflated content. For an object that is
 	 *            in whole object format, this is the same as the object size.
 	 *            For an object that is in a delta format, this is the size of
 	 *            the inflated delta instruction stream.
 	 * @throws IOException
 	 *             the underlying stream refused to accept the header.
 	 */
 	public final void writeHeader(ObjectToPack otp, long rawLength)
 			throws IOException {
 		ObjectToPack b = otp.getDeltaBase();
 		if (b != null && (b.isWritten() & ofsDelta)) { // Non-short-circuit logic is intentional
 			int n = objectHeader(rawLength, OBJ_OFS_DELTA, headerBuffer);
 			n = ofsDelta(count - b.getOffset(), headerBuffer, n);
 			write(headerBuffer, 0, n);
 		} else if (otp.isDeltaRepresentation()) {
 			int n = objectHeader(rawLength, OBJ_REF_DELTA, headerBuffer);
 			otp.getDeltaBaseId().copyRawTo(headerBuffer, n);
 			write(headerBuffer, 0, n + 20);
 		} else {
 			int n = objectHeader(rawLength, otp.getType(), headerBuffer);
 			write(headerBuffer, 0, n);
 		}
 	}

 	private static final int objectHeader(long len, int type, byte[] buf) {
 		byte b = (byte) ((type << 4) | (len & 0x0F));
 		int n = 0;
 		for (len >>>= 4; len != 0; len >>>= 7) {
 			buf[n++] = (byte) (0x80 | b);
 			b = (byte) (len & 0x7F);
 		}
 		buf[n++] = b;
 		return n;
 	}

 	private static final int ofsDelta(long diff, byte[] buf, int p) {
 		p += ofsDeltaVarIntLength(diff);
 		int n = p;
 		buf[--n] = (byte) (diff & 0x7F);
 		while ((diff >>>= 7) != 0)
 			buf[--n] = (byte) (0x80 | (--diff & 0x7F));
 		return p;
 	}

 	private static final int ofsDeltaVarIntLength(long v) {
 		int n = 1;
 		for (; (v >>>= 7) != 0; n++)
 			--v;
 		return n;
 	}

 	/** @return a temporary buffer writers can use to copy data with. */
 	public final byte[] getCopyBuffer() {
 		return copyBuffer;
 	}

 	void endObject() {
 		writeMonitor.update(1);
 	}

 	/** @return total number of bytes written since stream start. */
 	public final long length() {
 		return count;
 	}

 	/** @return obtain the current SHA-1 digest. */
 	final byte[] getDigest() {
 		return md.digest();
 	}
 }
	/*
	* Copyright (C) 2008-2009, Google Inc.
	* Copyright (C) 2008, Marek Zawirski <marek.zawirski@gmail.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.pack;

	import static org.eclipse.jgit.lib.Constants.OBJ_OFS_DELTA;
	import static org.eclipse.jgit.lib.Constants.OBJ_REF_DELTA;
	import static org.eclipse.jgit.lib.Constants.PACK_SIGNATURE;

	import java.io.IOException;
	import java.io.OutputStream;
	import java.security.MessageDigest;

	import org.eclipse.jgit.internal.JGitText;
	import org.eclipse.jgit.lib.Constants;
	import org.eclipse.jgit.lib.ProgressMonitor;
	import org.eclipse.jgit.util.NB;

	/** Custom output stream to support {@link PackWriter}. */
	public final class PackOutputStream extends OutputStream {
	private static final int BYTES_TO_WRITE_BEFORE_CANCEL_CHECK = 128 * 1024;

	private final ProgressMonitor writeMonitor;

	private final OutputStream out;

	private final PackWriter packWriter;

	private final MessageDigest md = Constants.newMessageDigest();

	private long count;

	private final byte[] headerBuffer = new byte[32];

	private final byte[] copyBuffer = new byte[64 << 10];

	private long checkCancelAt;

	private boolean ofsDelta;

	/**
	* Initialize a pack output stream.
	* <p>
	* This constructor is exposed to support debugging the JGit library only.
	* Application or storage level code should not create a PackOutputStream,
	* instead use {@link PackWriter}, and let the writer create the stream.
	*
	* @param writeMonitor
	* monitor to update on object output progress.
	* @param out
	* target stream to receive all object contents.
	* @param pw
	* packer that is going to perform the output.
	*/
	public PackOutputStream(final ProgressMonitor writeMonitor,
	final OutputStream out, final PackWriter pw) {
	this.writeMonitor = writeMonitor;
	this.out = out;
	this.packWriter = pw;
	this.checkCancelAt = BYTES_TO_WRITE_BEFORE_CANCEL_CHECK;
	}

	@Override
	public final void write(final int b) throws IOException {
	count++;
	out.write(b);
	md.update((byte) b);
	}

	@Override
	public final void write(final byte[] b, int off, int len)
	throws IOException {
	while (0 < len) {
	final int n = Math.min(len, BYTES_TO_WRITE_BEFORE_CANCEL_CHECK);
	count += n;

	if (checkCancelAt <= count) {
	if (writeMonitor.isCancelled()) {
	throw new IOException(
	JGitText.get().packingCancelledDuringObjectsWriting);
	}
	checkCancelAt = count + BYTES_TO_WRITE_BEFORE_CANCEL_CHECK;
	}

	out.write(b, off, n);
	md.update(b, off, n);

	off += n;
	len -= n;
	}
	}

	@Override
	public void flush() throws IOException {
	out.flush();
	}

	final void writeFileHeader(int version, long objectCount)
	throws IOException {
	System.arraycopy(PACK_SIGNATURE, 0, headerBuffer, 0, 4);
	NB.encodeInt32(headerBuffer, 4, version);
	NB.encodeInt32(headerBuffer, 8, (int) objectCount);
	write(headerBuffer, 0, 12);
	ofsDelta = packWriter.isDeltaBaseAsOffset();
	}

	/**
	* Write one object.
	*
	* If the object was already written, this method does nothing and returns
	* quickly. This case occurs whenever an object was written out of order in
	* order to ensure the delta base occurred before the object that needs it.
	*
	* @param otp
	* the object to write.
	* @throws IOException
	* the object cannot be read from the object reader, or the
	* output stream is no longer accepting output. Caller must
	* examine the type of exception and possibly its message to
	* distinguish between these cases.
	*/
	public final void writeObject(ObjectToPack otp) throws IOException {
	packWriter.writeObject(this, otp);
	}

	/**
	* Commits the object header onto the stream.
	* <p>
	* Once the header has been written, the object representation must be fully
	* output, or packing must abort abnormally.
	*
	* @param otp
	* the object to pack. Header information is obtained.
	* @param rawLength
	* number of bytes of the inflated content. For an object that is
	* in whole object format, this is the same as the object size.
	* For an object that is in a delta format, this is the size of
	* the inflated delta instruction stream.
	* @throws IOException
	* the underlying stream refused to accept the header.
	*/
	public final void writeHeader(ObjectToPack otp, long rawLength)
	throws IOException {
	ObjectToPack b = otp.getDeltaBase();
	if (b != null && (b.isWritten() & ofsDelta)) { // Non-short-circuit logic is intentional
	int n = objectHeader(rawLength, OBJ_OFS_DELTA, headerBuffer);
	n = ofsDelta(count - b.getOffset(), headerBuffer, n);
	write(headerBuffer, 0, n);
	} else if (otp.isDeltaRepresentation()) {
	int n = objectHeader(rawLength, OBJ_REF_DELTA, headerBuffer);
	otp.getDeltaBaseId().copyRawTo(headerBuffer, n);
	write(headerBuffer, 0, n + 20);
	} else {
	int n = objectHeader(rawLength, otp.getType(), headerBuffer);
	write(headerBuffer, 0, n);
	}
	}

	private static final int objectHeader(long len, int type, byte[] buf) {
	byte b = (byte) ((type << 4) \| (len & 0x0F));
	int n = 0;
	for (len >>>= 4; len != 0; len >>>= 7) {
	buf[n++] = (byte) (0x80 \| b);
	b = (byte) (len & 0x7F);
	}
	buf[n++] = b;
	return n;
	}

	private static final int ofsDelta(long diff, byte[] buf, int p) {
	p += ofsDeltaVarIntLength(diff);
	int n = p;
	buf[--n] = (byte) (diff & 0x7F);
	while ((diff >>>= 7) != 0)
	buf[--n] = (byte) (0x80 \| (--diff & 0x7F));
	return p;
	}

	private static final int ofsDeltaVarIntLength(long v) {
	int n = 1;
	for (; (v >>>= 7) != 0; n++)
	--v;
	return n;
	}

	/** @return a temporary buffer writers can use to copy data with. */
	public final byte[] getCopyBuffer() {
	return copyBuffer;
	}

	void endObject() {
	writeMonitor.update(1);
	}

	/** @return total number of bytes written since stream start. */
	public final long length() {
	return count;
	}

	/** @return obtain the current SHA-1 digest. */
	final byte[] getDigest() {
	return md.digest();
	}
	}