org.eclipse.jgit.lfs.test/src/org/eclipse/jgit/lfs/test/LongObjectIdTestUtils.java

/*
 * Copyright (C) 2015, 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.lfs.test;

import java.io.BufferedInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.InputStream;
import java.nio.charset.StandardCharsets;
import java.nio.file.Files;
import java.nio.file.Path;
import java.security.MessageDigest;

import org.eclipse.jgit.lfs.lib.Constants;
import org.eclipse.jgit.lfs.lib.LongObjectId;

public class LongObjectIdTestUtils {

	/**
	 * Create id as hash of the given string.
	 *
	 * @param s
	 *            the string to hash
	 * @return id calculated by hashing string
	 */
	public static LongObjectId hash(String s) {
		MessageDigest md = Constants.newMessageDigest();
		md.update(s.getBytes(StandardCharsets.UTF_8));
		return LongObjectId.fromRaw(md.digest());
	}

	/**
	 * Create id as hash of a file content
	 *
	 * @param file
	 *            the file to hash
	 * @return id calculated by hashing file content
	 * @throws FileNotFoundException
	 *             if file doesn't exist
	 * @throws IOException
	 */
	public static LongObjectId hash(Path file)
			throws FileNotFoundException, IOException {
		MessageDigest md = Constants.newMessageDigest();
		try (InputStream is = new BufferedInputStream(
				Files.newInputStream(file))) {
			final byte[] buffer = new byte[4096];
			for (int read = 0; (read = is.read(buffer)) != -1;) {
				md.update(buffer, 0, read);
			}
		}
		return LongObjectId.fromRaw(md.digest());
	}
}