Add "jgit archive" tool that writes a tree as a ZIP file

C Git's "git archive" command represents a tree object using a
standard archival format like tar, zip, or tgz, ready for consumption
by other, git-unaware users or tools.

Add a bare-bones analagous "jgit archive" command to show what is
possible, supporting only ZIP format for now.  It uses java.util.zip
which is not aware of the InfoZIP extensions for representing symlinks
and file permissions, so symlinks, executable files, and submodule
entries are represented as plain text files.

Making this functionality available from the library, improving
handling of special entries, and support for other output formats are
left for later patches.  Ultimately the intent is to offer a
TreeArchiveStream class for use by web frontends like Gitiles to offer
"download as zip/tgz/txz" links and use by, for example, code search
tools to get easy access to the content of git tree objects.

Test with "jgit archive my-favorite-tree >out.zip".

Change-Id: Ib590f173ceff3df4b58493cecccd6b9a1b355e3d

org.eclipse.jgit.pgm.test/tst/org/eclipse/jgit/pgm/ArchiveTest.java

@@ -0,0 +1,175 @@
+/*
+ * 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
+ * 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.pgm;
+
+import static org.junit.Assert.assertArrayEquals;
+
+import java.io.BufferedReader;
+import java.io.ByteArrayInputStream;
+import java.io.InputStreamReader;
+import java.io.IOException;
+
+import java.lang.String;
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.List;
+import java.util.zip.ZipEntry;
+import java.util.zip.ZipInputStream;
+
+import org.eclipse.jgit.api.Git;
+import org.eclipse.jgit.lib.CLIRepositoryTestCase;
+import org.eclipse.jgit.pgm.CLIGitCommand;
+import org.junit.Before;
+import org.junit.Ignore;
+import org.junit.Test;
+
+public class ArchiveTest extends CLIRepositoryTestCase {
+	private Git git;
+	private String emptyTree;
+
+	@Override
+	@Before
+	public void setUp() throws Exception {
+		super.setUp();
+		git = new Git(db);
+		git.commit().setMessage("initial commit").call();
+		emptyTree = db.resolve("HEAD^{tree}").abbreviate(12).name();
+	}
+
+	@Ignore("Some versions of java.util.zip refuse to write an empty ZIP")
+	@Test
+	public void testEmptyArchive() throws Exception {
+		final byte[] result = CLIGitCommand.rawExecute( //
+				"git archive " + emptyTree, db);
+		assertArrayEquals(new String[0], listZipEntries(result));
+	}
+
+	@Test
+	public void testArchiveWithFiles() throws Exception {
+		writeTrashFile("a", "a file with content!");
+		writeTrashFile("c", ""); // empty file
+		writeTrashFile("unrelated", "another file, just for kicks");
+		git.add().addFilepattern("a").call();
+		git.add().addFilepattern("c").call();
+		git.commit().setMessage("populate toplevel").call();
+
+		final byte[] result = CLIGitCommand.rawExecute( //
+				"git archive HEAD", db);
+		assertArrayEquals(new String[] { "a", "c" }, //
+				listZipEntries(result));
+	}
+
+	@Test
+	public void testArchiveWithSubdir() throws Exception {
+		writeTrashFile("a", "a file with content!");
+		writeTrashFile("b.c", "before subdir in git sort order");
+		writeTrashFile("b0c", "after subdir in git sort order");
+		writeTrashFile("c", "");
+		git.add().addFilepattern("a").call();
+		git.add().addFilepattern("b.c").call();
+		git.add().addFilepattern("b0c").call();
+		git.add().addFilepattern("c").call();
+		git.commit().setMessage("populate toplevel").call();
+		writeTrashFile("b/b", "file in subdirectory");
+		writeTrashFile("b/a", "another file in subdirectory");
+		git.add().addFilepattern("b").call();
+		git.commit().setMessage("add subdir").call();
+
+		final byte[] result = CLIGitCommand.rawExecute( //
+				"git archive master", db);
+		String[] expect = { "a", "b.c", "b0c", "b/a", "b/b", "c" };
+		String[] actual = listZipEntries(result);
+
+		Arrays.sort(expect);
+		Arrays.sort(actual);
+		assertArrayEquals(expect, actual);
+	}
+
+	@Test
+	public void testArchivePreservesContent() throws Exception {
+		final String payload = "“The quick brown fox jumps over the lazy dog!”";
+		writeTrashFile("xyzzy", payload);
+		git.add().addFilepattern("xyzzy").call();
+		git.commit().setMessage("add file with content").call();
+
+		final byte[] result = CLIGitCommand.rawExecute( //
+				"git archive HEAD", db);
+		assertArrayEquals(new String[] { payload }, //
+				zipEntryContent(result, "xyzzy"));
+	}
+
+	private static String[] listZipEntries(byte[] zipData) throws IOException {
+		final List<String> l = new ArrayList<String>();
+		final ZipInputStream in = new ZipInputStream( //
+				new ByteArrayInputStream(zipData));
+
+		ZipEntry e;
+		while ((e = in.getNextEntry()) != null)
+			l.add(e.getName());
+		in.close();
+		return l.toArray(new String[l.size()]);
+	}
+
+	private static String[] zipEntryContent(byte[] zipData, String path) //
+			throws IOException {
+		final ZipInputStream in = new ZipInputStream( //
+				new ByteArrayInputStream(zipData));
+		ZipEntry e;
+		while ((e = in.getNextEntry()) != null) {
+			if (!e.getName().equals(path))
+				continue;
+
+			// found!
+			final List<String> l = new ArrayList<String>();
+			final BufferedReader reader = new BufferedReader( //
+					new InputStreamReader(in, "UTF-8"));
+			String line;
+			while ((line = reader.readLine()) != null)
+				l.add(line);
+			return l.toArray(new String[l.size()]);
+		}
+
+		// not found
+		return null;
+	}
+}

org.eclipse.jgit.pgm/META-INF/services/org.eclipse.jgit.pgm.TextBuiltin

@@ -1,5 +1,6 @@
 org.eclipse.jgit.pgm.Add
 org.eclipse.jgit.pgm.AmazonS3Client
+org.eclipse.jgit.pgm.Archive
 org.eclipse.jgit.pgm.Blame
 org.eclipse.jgit.pgm.Branch
 org.eclipse.jgit.pgm.Checkout

org.eclipse.jgit.pgm/resources/org/eclipse/jgit/pgm/CLIText.properties

@@ -8,6 +8,7 @@ N=N
 IPZillaPasswordPrompt=IPZilla Password
 alreadyOnBranch=Already on ''{0}''
 alreadyUpToDate=Already up-to-date.
+archiveEntryModeIgnored=warning: mode of {0} ignored
 authorInfo=Author: {0} <{1}>
 averageMSPerRead=average {0} ms/read
 branchAlreadyExists=A branch named ''{0}'' already exists.
@@ -156,6 +157,7 @@ tagAlreadyExists=tag ''{0}'' already exists
 tagLabel=tag
 taggerInfo=Tagger: {0} <{1}>
 timeInMilliSeconds={0} ms
+treeIsRequired=argument tree is required
 tooManyRefsGiven=Too many refs given
 unknownIoErrorStdout=An unknown I/O error occurred on standard output
 unknownMergeStrategy=unknown merge strategy {0} specified
@@ -193,6 +195,7 @@ usage_actOnRemoteTrackingBranches=act on remote-tracking branches
 usage_addFileContentsToTheIndex=Add file contents to the index
 usage_alterTheDetailShown=alter the detail shown
 usage_approveDestructionOfRepository=approve destruction of repository
+usage_archive=zip up files from the named tree
 usage_blameLongRevision=show long revision
 usage_blameRange=annotate only the given range
 usage_blameRawTimestamp=show raw timestamp

org.eclipse.jgit.pgm/src/org/eclipse/jgit/pgm/Archive.java

@@ -0,0 +1,104 @@
+/*
+ * 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
+ * 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.pgm;
+
+import java.lang.String;
+import java.lang.System;
+import java.text.MessageFormat;
+import java.util.zip.ZipEntry;
+import java.util.zip.ZipOutputStream;
+
+import org.eclipse.jgit.lib.FileMode;
+import org.eclipse.jgit.lib.MutableObjectId;
+import org.eclipse.jgit.lib.ObjectLoader;
+import org.eclipse.jgit.lib.ObjectReader;
+import org.eclipse.jgit.pgm.CLIText;
+import org.eclipse.jgit.pgm.TextBuiltin;
+import org.eclipse.jgit.treewalk.AbstractTreeIterator;
+import org.eclipse.jgit.treewalk.TreeWalk;
+import org.kohsuke.args4j.Argument;
+
+@Command(common = true, usage = "usage_archive")
+class Archive extends TextBuiltin {
+	@Argument(index = 0, metaVar = "metaVar_treeish")
+	private AbstractTreeIterator tree;
+
+	@Override
+	protected void run() throws Exception {
+		final TreeWalk walk = new TreeWalk(db);
+		final ObjectReader reader = walk.getObjectReader();
+		final MutableObjectId idBuf = new MutableObjectId();
+		final ZipOutputStream out = new ZipOutputStream(outs);
+
+		if (tree == null)
+			throw die(CLIText.get().treeIsRequired);
+
+		walk.reset();
+		walk.addTree(tree);
+		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);
+			final ZipEntry entry = new ZipEntry(name);
+			final ObjectLoader loader = reader.open(idBuf);
+			entry.setSize(loader.getSize());
+			out.putNextEntry(entry);
+			loader.copyTo(out);
+
+			if (mode != FileMode.REGULAR_FILE)
+				System.err.println(MessageFormat.format( //
+						CLIText.get().archiveEntryModeIgnored, //
+						name));
+		}
+
+		out.close();
+	}
+}

org.eclipse.jgit.pgm/src/org/eclipse/jgit/pgm/CLIText.java

@@ -77,6 +77,7 @@ public class CLIText extends TranslationBundle {
 	/***/ public String IPZillaPasswordPrompt;
 	/***/ public String alreadyOnBranch;
 	/***/ public String alreadyUpToDate;
+	/***/ public String archiveEntryModeIgnored;
 	/***/ public String authorInfo;
 	/***/ public String averageMSPerRead;
 	/***/ public String branchAlreadyExists;
@@ -220,6 +221,7 @@ public class CLIText extends TranslationBundle {
 	/***/ public String taggerInfo;
 	/***/ public String timeInMilliSeconds;
 	/***/ public String tooManyRefsGiven;
+	/***/ public String treeIsRequired;
 	/***/ public char[] unknownIoErrorStdout;
 	/***/ public String unknownMergeStrategy;
 	/***/ public String unmergedPaths;