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- /*
- * Copyright (C) 2009, The Android Open Source Project
- * Copyright (C) 2009, Shawn O. Pearce <spearce@spearce.org>
- * Copyright (C) 2018, David Pursehouse <david.pursehouse@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.lib;
-
- import static org.eclipse.jgit.lib.Constants.OBJECT_ID_LENGTH;
-
- import java.io.IOException;
- import java.io.InputStream;
- import java.io.OutputStream;
-
- import org.eclipse.jgit.annotations.NonNull;
- import org.eclipse.jgit.annotations.Nullable;
- import org.eclipse.jgit.util.IO;
-
- /**
- * Helper to serialize {@link ObjectId} instances. {@link ObjectId} is already
- * serializable, but this class provides methods to handle null and non-null
- * instances.
- *
- * @since 4.11
- */
- public class ObjectIdSerializer {
- /*
- * Marker to indicate a null ObjectId instance.
- */
- private static final byte NULL_MARKER = 0;
-
- /*
- * Marker to indicate a non-null ObjectId instance.
- */
- private static final byte NON_NULL_MARKER = 1;
-
- /**
- * Write a possibly null {@link ObjectId} to the stream, using markers to
- * differentiate null and non-null instances.
- *
- * <p>
- * If the id is non-null, writes a {@link #NON_NULL_MARKER} followed by the
- * id's words. If it is null, writes a {@link #NULL_MARKER} and nothing
- * else.
- *
- * @param out
- * the output stream
- * @param id
- * the object id to serialize; may be null
- * @throws IOException
- * the stream writing failed
- */
- public static void write(OutputStream out, @Nullable AnyObjectId id)
- throws IOException {
- if (id != null) {
- out.write(NON_NULL_MARKER);
- writeWithoutMarker(out, id);
- } else {
- out.write(NULL_MARKER);
- }
- }
-
- /**
- * Write a non-null {@link ObjectId} to the stream.
- *
- * @param out
- * the output stream
- * @param id
- * the object id to serialize; never null
- * @throws IOException
- * the stream writing failed
- * @since 4.11
- */
- public static void writeWithoutMarker(OutputStream out, @NonNull AnyObjectId id)
- throws IOException {
- id.copyRawTo(out);
- }
-
- /**
- * Read a possibly null {@link ObjectId} from the stream.
- *
- * Reads the first byte of the stream, which is expected to be either
- * {@link #NON_NULL_MARKER} or {@link #NULL_MARKER}.
- *
- * @param in
- * the input stream
- * @return the object id, or null
- * @throws IOException
- * there was an error reading the stream
- */
- @Nullable
- public static ObjectId read(InputStream in) throws IOException {
- byte marker = (byte) in.read();
- switch (marker) {
- case NULL_MARKER:
- return null;
- case NON_NULL_MARKER:
- return readWithoutMarker(in);
- default:
- throw new IOException("Invalid flag before ObjectId: " + marker); //$NON-NLS-1$
- }
- }
-
- /**
- * Read a non-null {@link ObjectId} from the stream.
- *
- * @param in
- * the input stream
- * @return the object id; never null
- * @throws IOException
- * there was an error reading the stream
- * @since 4.11
- */
- @NonNull
- public static ObjectId readWithoutMarker(InputStream in) throws IOException {
- final byte[] b = new byte[OBJECT_ID_LENGTH];
- IO.readFully(in, b, 0, OBJECT_ID_LENGTH);
- return ObjectId.fromRaw(b);
- }
-
- private ObjectIdSerializer() {
- }
- }
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