org.eclipse.jgit.pgm/src/org/eclipse/jgit/pgm/archive/ArchiveCommand.java

/*
 * Copyright (C) 2012 Google Inc.
 * 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
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 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
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package org.eclipse.jgit.pgm.archive;

import java.io.IOException;
import java.io.OutputStream;
import java.util.EnumMap;
import java.util.Map;

import org.apache.commons.compress.archivers.ArchiveOutputStream;
import org.apache.commons.compress.archivers.tar.TarArchiveEntry;
import org.apache.commons.compress.archivers.tar.TarArchiveOutputStream;
import org.apache.commons.compress.archivers.tar.TarConstants;
import org.apache.commons.compress.archivers.zip.ZipArchiveEntry;
import org.apache.commons.compress.archivers.zip.ZipArchiveOutputStream;
import org.eclipse.jgit.api.Git;
import org.eclipse.jgit.api.GitCommand;
import org.eclipse.jgit.api.errors.GitAPIException;
import org.eclipse.jgit.api.errors.JGitInternalException;
import org.eclipse.jgit.lib.FileMode;
import org.eclipse.jgit.lib.MutableObjectId;
import org.eclipse.jgit.lib.ObjectId;
import org.eclipse.jgit.lib.ObjectLoader;
import org.eclipse.jgit.lib.ObjectReader;
import org.eclipse.jgit.lib.Repository;
import org.eclipse.jgit.pgm.internal.CLIText;
import org.eclipse.jgit.revwalk.RevWalk;
import org.eclipse.jgit.treewalk.TreeWalk;

/**
 * Create an archive of files from a named tree.
 * <p>
 * Examples (<code>git</code> is a {@link Git} instance):
 * <p>
 * Create a tarball from HEAD:
 *
 * <pre>
 * cmd = new ArchiveCommand(git.getRepository());
 * try {
 *	cmd.setTree(db.resolve(&quot;HEAD&quot;))
 *		.setOutputStream(out).call();
 * } finally {
 *	cmd.release();
 * }
 * </pre>
 * <p>
 * Create a ZIP file from master:
 *
 * <pre>
 * try {
 *	cmd.setTree(db.resolve(&quot;master&quot;))
 *		.setFormat(ArchiveCommand.Format.ZIP)
 *		.setOutputStream(out).call();
 * } finally {
 *	cmd.release();
 * }
 * </pre>
 *
 * @see <a href="http://git-htmldocs.googlecode.com/git/git-archive.html"
 *      >Git documentation about archive</a>
 *
 * @since 3.0
 */
public class ArchiveCommand extends GitCommand<OutputStream> {
	/**
	 * Available archival formats (corresponding to values for
	 * the --format= option)
	 */
	public static enum Format {
		/** Zip format */
		ZIP,

		/** Posix TAR-format */
		TAR
	}

	private static interface Archiver {
		ArchiveOutputStream createArchiveOutputStream(OutputStream s);
		void putEntry(String path, FileMode mode, //
				ObjectLoader loader, ArchiveOutputStream out) //
				throws IOException;
	}

	private static final Map<Format, Archiver> formats;

	static {
		Map<Format, Archiver> fmts = new EnumMap<Format, Archiver>(Format.class);
		fmts.put(Format.ZIP, new Archiver() {
			public ArchiveOutputStream createArchiveOutputStream(OutputStream s) {
				return new ZipArchiveOutputStream(s);
			}

			public void putEntry(String path, FileMode mode, //
					ObjectLoader loader, ArchiveOutputStream out) //
					throws IOException {
				final ZipArchiveEntry entry = new ZipArchiveEntry(path);

				if (mode == FileMode.REGULAR_FILE) {
					// ok
				} else if (mode == FileMode.EXECUTABLE_FILE
						|| mode == FileMode.SYMLINK) {
					entry.setUnixMode(mode.getBits());
				} else {
					// TODO(jrn): Let the caller know the tree contained
					// an entry with unsupported mode (e.g., a submodule).
				}
				entry.setSize(loader.getSize());
				out.putArchiveEntry(entry);
				loader.copyTo(out);
				out.closeArchiveEntry();
			}
		});
		fmts.put(Format.TAR, new Archiver() {
			public ArchiveOutputStream createArchiveOutputStream(OutputStream s) {
				return new TarArchiveOutputStream(s);
			}

			public void putEntry(String path, FileMode mode, //
					ObjectLoader loader, ArchiveOutputStream out) //
					throws IOException {
				if (mode == FileMode.SYMLINK) {
					final TarArchiveEntry entry = new TarArchiveEntry( //
							path, TarConstants.LF_SYMLINK);
					entry.setLinkName(new String( //
							loader.getCachedBytes(100), "UTF-8")); //$NON-NLS-1$
					out.putArchiveEntry(entry);
					out.closeArchiveEntry();
					return;
				}

				final TarArchiveEntry entry = new TarArchiveEntry(path);
				if (mode == FileMode.REGULAR_FILE ||
				    mode == FileMode.EXECUTABLE_FILE) {
					entry.setMode(mode.getBits());
				} else {
					// TODO(jrn): Let the caller know the tree contained
					// an entry with unsupported mode (e.g., a submodule).
				}
				entry.setSize(loader.getSize());
				out.putArchiveEntry(entry);
				loader.copyTo(out);
				out.closeArchiveEntry();
			}
		});
		formats = fmts;
	}

	private OutputStream out;
	private TreeWalk walk;
	private Format format = Format.TAR;

	/**
	 * @param repo
	 */
	public ArchiveCommand(Repository repo) {
		super(repo);
		walk = new TreeWalk(repo);
	}

	/**
	 * Release any resources used by the internal ObjectReader.
	 * <p>
	 * This does not close the output stream set with setOutputStream, which
	 * belongs to the caller.
	 */
	public void release() {
		walk.release();
	}

	/**
	 * @return the stream to which the archive has been written
	 */
	@Override
	public OutputStream call() throws GitAPIException {
		final MutableObjectId idBuf = new MutableObjectId();
		final Archiver fmt = formats.get(format);
		final ArchiveOutputStream outa = fmt.createArchiveOutputStream(out);
		final ObjectReader reader = walk.getObjectReader();

		try {
			try {
				walk.setRecursive(true);
				while (walk.next()) {
					final String name = walk.getPathString();
					final FileMode mode = walk.getFileMode(0);

					if (mode == FileMode.TREE)
						// ZIP entries for directories are optional.
						// Leave them out, mimicking "git archive".
						continue;

					walk.getObjectId(idBuf, 0);
					fmt.putEntry(name, mode, reader.open(idBuf), outa);
				}
			} finally {
				outa.close();
			}
		} catch (IOException e) {
			// TODO(jrn): Throw finer-grained errors.
			throw new JGitInternalException(
					CLIText.get().exceptionCaughtDuringExecutionOfArchiveCommand, e);
		}

		return out;
	}

	/**
	 * @param tree
	 *            the tag, commit, or tree object to produce an archive for
	 * @return this
	 * @throws IOException
	 */
	public ArchiveCommand setTree(ObjectId tree) throws IOException {
		final RevWalk rw = new RevWalk(walk.getObjectReader());
		walk.reset(rw.parseTree(tree));
		return this;
	}

	/**
	 * @param out
	 *	      the stream to which to write the archive
	 * @return this
	 */
	public ArchiveCommand setOutputStream(OutputStream out) {
		this.out = out;
		return this;
	}

	/**
	 * @param fmt
	 *	      archive format (e.g., Format.TAR)
	 * @return this
	 */
	public ArchiveCommand setFormat(Format fmt) {
		this.format = fmt;
		return this;
	}
}