Support atomic push in JGit client

This should mirror the behavior of `git push --atomic` where the
client asks the server to apply all-or-nothing. Some JGit servers
already support this based on a custom DFS backend. InMemoryRepository
is extended to support atomic push for unit testing purposes.

Local disk server side support inside of JGit is a more complex animal
due to the excessive amount of file locking required to protect every
reference as a loose reference.

Change-Id: I15083fbe48447678e034afeffb4639572a32f50c

1 files changed, 200 insertions, 0 deletions

diff --git a/org.eclipse.jgit.test/tst/org/eclipse/jgit/transport/AtomicPushTest.java b/org.eclipse.jgit.test/tst/org/eclipse/jgit/transport/AtomicPushTest.java
new file mode 100644
index 0000000000..782e414b62
--- /dev/null
+++ b/org.eclipse.jgit.test/tst/org/eclipse/jgit/transport/AtomicPushTest.java
@@ -0,0 +1,200 @@
+/*
+ * Copyright (C) 2015, 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.transport;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertSame;
+import static org.junit.Assert.fail;
+
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.List;
+
+import org.eclipse.jgit.errors.TransportException;
+import org.eclipse.jgit.internal.JGitText;
+import org.eclipse.jgit.internal.storage.dfs.DfsRepositoryDescription;
+import org.eclipse.jgit.internal.storage.dfs.InMemoryRepository;
+import org.eclipse.jgit.lib.Constants;
+import org.eclipse.jgit.lib.NullProgressMonitor;
+import org.eclipse.jgit.lib.ObjectId;
+import org.eclipse.jgit.lib.ObjectInserter;
+import org.eclipse.jgit.lib.Repository;
+import org.eclipse.jgit.transport.resolver.ReceivePackFactory;
+import org.eclipse.jgit.transport.resolver.ServiceNotAuthorizedException;
+import org.eclipse.jgit.transport.resolver.ServiceNotEnabledException;
+import org.junit.After;
+import org.junit.Before;
+import org.junit.Test;
+
+public class AtomicPushTest {
+	private URIish uri;
+	private TestProtocol<Object> testProtocol;
+	private Object ctx = new Object();
+	private InMemoryRepository server;
+	private InMemoryRepository client;
+	private ObjectId obj1;
+	private ObjectId obj2;
+
+	@Before
+	public void setUp() throws Exception {
+		server = newRepo("server");
+		client = newRepo("client");
+		testProtocol = new TestProtocol<>(
+				null,
+				new ReceivePackFactory<Object>() {
+					@Override
+					public ReceivePack create(Object req, Repository db)
+							throws ServiceNotEnabledException,
+							ServiceNotAuthorizedException {
+						return new ReceivePack(db);
+					}
+				});
+		uri = testProtocol.register(ctx, server);
+
+		try (ObjectInserter ins = client.newObjectInserter()) {
+			obj1 = ins.insert(Constants.OBJ_BLOB, Constants.encode("test"));
+			obj2 = ins.insert(Constants.OBJ_BLOB, Constants.encode("file"));
+			ins.flush();
+		}
+	}
+
+	@After
+	public void tearDown() {
+		Transport.unregister(testProtocol);
+	}
+
+	private static InMemoryRepository newRepo(String name) {
+		return new InMemoryRepository(new DfsRepositoryDescription(name));
+	}
+
+	@Test
+	public void pushNonAtomic() throws Exception {
+		PushResult r;
+		server.setPerformsAtomicTransactions(false);
+		Transport tn = testProtocol.open(uri, client, "server");
+		try {
+			tn.setPushAtomic(false);
+			r = tn.push(NullProgressMonitor.INSTANCE, commands());
+		} finally {
+			tn.close();
+		}
+
+		RemoteRefUpdate one = r.getRemoteUpdate("refs/heads/one");
+		RemoteRefUpdate two = r.getRemoteUpdate("refs/heads/two");
+		assertSame(RemoteRefUpdate.Status.OK, one.getStatus());
+		assertSame(
+				RemoteRefUpdate.Status.REJECTED_REMOTE_CHANGED,
+				two.getStatus());
+	}
+
+	@Test
+	public void pushAtomicClientGivesUpEarly() throws Exception {
+		PushResult r;
+		Transport tn = testProtocol.open(uri, client, "server");
+		try {
+			tn.setPushAtomic(true);
+			r = tn.push(NullProgressMonitor.INSTANCE, commands());
+		} finally {
+			tn.close();
+		}
+
+		RemoteRefUpdate one = r.getRemoteUpdate("refs/heads/one");
+		RemoteRefUpdate two = r.getRemoteUpdate("refs/heads/two");
+		assertSame(
+				RemoteRefUpdate.Status.REJECTED_OTHER_REASON,
+				one.getStatus());
+		assertSame(
+				RemoteRefUpdate.Status.REJECTED_REMOTE_CHANGED,
+				two.getStatus());
+		assertEquals(JGitText.get().transactionAborted, one.getMessage());
+	}
+
+	@Test
+	public void pushAtomicDisabled() throws Exception {
+		List<RemoteRefUpdate> cmds = new ArrayList<>();
+		cmds.add(new RemoteRefUpdate(
+				null, null,
+				obj1, "refs/heads/one",
+				true /* force update */,
+				null /* no local tracking ref */,
+				ObjectId.zeroId()));
+		cmds.add(new RemoteRefUpdate(
+				null, null,
+				obj2, "refs/heads/two",
+				true /* force update */,
+				null /* no local tracking ref */,
+				ObjectId.zeroId()));
+
+		server.setPerformsAtomicTransactions(false);
+		Transport tn = testProtocol.open(uri, client, "server");
+		try {
+			tn.setPushAtomic(true);
+			tn.push(NullProgressMonitor.INSTANCE, cmds);
+			fail("did not throw TransportException");
+		} catch (TransportException e) {
+			assertEquals(
+					uri + ": " + JGitText.get().atomicPushNotSupported,
+					e.getMessage());
+		} finally {
+			tn.close();
+		}
+	}
+
+	private List<RemoteRefUpdate> commands() throws IOException {
+		List<RemoteRefUpdate> cmds = new ArrayList<>();
+		cmds.add(new RemoteRefUpdate(
+				null, null,
+				obj1, "refs/heads/one",
+				true /* force update */,
+				null /* no local tracking ref */,
+				ObjectId.zeroId()));
+		cmds.add(new RemoteRefUpdate(
+				null, null,
+				obj2, "refs/heads/two",
+				true /* force update */,
+				null /* no local tracking ref */,
+				obj1));
+		return cmds;
+	}
+}