jgit: Add DfsBundleWriter

DfsBundleWriter writes out the entire repository to a Git bundle file.
It packs all objects included in the packfile by concatenating all pack
files. This makes the bundle creation fast and cheap. Useful for backing
up a repository as-is.

Change-Id: Iee20e4b1ab45b2a178dde8c72093c0dd83f04805
Signed-off-by: Masaya Suzuki <masayasuzuki@google.com>

1 files changed, 85 insertions, 0 deletions

diff --git a/org.eclipse.jgit.test/tst/org/eclipse/jgit/internal/storage/dfs/DfsBundleWriterTest.java b/org.eclipse.jgit.test/tst/org/eclipse/jgit/internal/storage/dfs/DfsBundleWriterTest.java
new file mode 100644
index 0000000000..4238ee6bf0
--- /dev/null
+++ b/org.eclipse.jgit.test/tst/org/eclipse/jgit/internal/storage/dfs/DfsBundleWriterTest.java
@@ -0,0 +1,85 @@
+/*
+ * Copyright (c) 2020, Google LLC  and others
+ *
+ * This program and the accompanying materials are made available under the
+ * terms of the Eclipse Distribution License v. 1.0 which is available at
+ * http://www.eclipse.org/org/documents/edl-v10.php.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+package org.eclipse.jgit.internal.storage.dfs;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertNotNull;
+import static org.junit.Assert.assertTrue;
+
+import java.io.ByteArrayInputStream;
+import java.io.ByteArrayOutputStream;
+import java.io.IOException;
+import java.util.Collections;
+import java.util.Set;
+
+import org.eclipse.jgit.junit.TestRepository;
+import org.eclipse.jgit.lib.NullProgressMonitor;
+import org.eclipse.jgit.lib.Ref;
+import org.eclipse.jgit.lib.Repository;
+import org.eclipse.jgit.revwalk.RevCommit;
+import org.eclipse.jgit.transport.FetchResult;
+import org.eclipse.jgit.transport.RefSpec;
+import org.eclipse.jgit.transport.TransportBundleStream;
+import org.eclipse.jgit.transport.URIish;
+import org.junit.Before;
+import org.junit.Test;
+
+public class DfsBundleWriterTest {
+	private TestRepository<InMemoryRepository> git;
+
+	private InMemoryRepository repo;
+
+	@Before
+	public void setUp() throws IOException {
+		DfsRepositoryDescription desc = new DfsRepositoryDescription("test");
+		git = new TestRepository<>(new InMemoryRepository(desc));
+		repo = git.getRepository();
+	}
+
+	@Test
+	public void testRepo() throws Exception {
+		RevCommit commit0 = git.commit().message("0").create();
+		RevCommit commit1 = git.commit().message("1").parent(commit0).create();
+		git.update("master", commit1);
+
+		RevCommit commit2 = git.commit().message("0").create();
+
+		byte[] bundle = makeBundle();
+		try (Repository newRepo = new InMemoryRepository(
+				new DfsRepositoryDescription("copy"))) {
+			fetchFromBundle(newRepo, bundle);
+			Ref ref = newRepo.exactRef("refs/heads/master");
+			assertNotNull(ref);
+			assertEquals(commit1.toObjectId(), ref.getObjectId());
+
+			// Unreferenced objects are included as well.
+			assertTrue(newRepo.getObjectDatabase().has(commit2));
+		}
+	}
+
+	private byte[] makeBundle() throws IOException {
+		ByteArrayOutputStream out = new ByteArrayOutputStream();
+		DfsBundleWriter.writeEntireRepositoryAsBundle(
+				NullProgressMonitor.INSTANCE, out, repo);
+		return out.toByteArray();
+	}
+
+	private static FetchResult fetchFromBundle(Repository newRepo,
+			byte[] bundle) throws Exception {
+		URIish uri = new URIish("in-memory://");
+		ByteArrayInputStream in = new ByteArrayInputStream(bundle);
+		RefSpec rs = new RefSpec("refs/heads/*:refs/heads/*");
+		Set<RefSpec> refs = Collections.singleton(rs);
+		try (TransportBundleStream transport = new TransportBundleStream(
+				newRepo, uri, in)) {
+			return transport.fetch(NullProgressMonitor.INSTANCE, refs);
+		}
+	}
+}