| /* |
| * 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() { |
| } |
| } |