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  package org.eclipse.jgit.internal.storage.reftree;
  
  import static org.eclipse.jgit.lib.Constants.HEAD;
  import static org.eclipse.jgit.lib.Constants.R_HEADS;
  import static org.eclipse.jgit.lib.Constants.R_TAGS;
  import static org.eclipse.jgit.lib.Ref.Storage.LOOSE;
  import static org.eclipse.jgit.lib.Ref.Storage.NEW;
  import static org.eclipse.jgit.transport.ReceiveCommand.Result.LOCK_FAILURE;
  import static org.eclipse.jgit.transport.ReceiveCommand.Result.NOT_ATTEMPTED;
  import static org.eclipse.jgit.transport.ReceiveCommand.Result.REJECTED_OTHER_REASON;
  import static org.junit.Assert.assertEquals;
  import static org.junit.Assert.assertFalse;
  import static org.junit.Assert.assertNotNull;
  import static org.junit.Assert.assertNull;
  import static org.junit.Assert.assertSame;
  import static org.junit.Assert.assertTrue;
  
  import java.io.IOException;
  import java.util.Arrays;
  import java.util.Collections;
  
  import org.eclipse.jgit.errors.MissingObjectException;
  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.junit.TestRepository;
  import org.eclipse.jgit.lib.ObjectId;
  import org.eclipse.jgit.lib.ObjectIdRef;
  import org.eclipse.jgit.lib.ObjectInserter;
  import org.eclipse.jgit.lib.ObjectReader;
  import org.eclipse.jgit.lib.Ref;
  import org.eclipse.jgit.lib.SymbolicRef;
  import org.eclipse.jgit.revwalk.RevBlob;
  import org.eclipse.jgit.revwalk.RevTag;
  import org.eclipse.jgit.revwalk.RevWalk;
  import org.eclipse.jgit.transport.ReceiveCommand;
  import org.junit.Before;
  import org.junit.Test;
  
  public class RefTreeTest {
  	private static final String R_MASTER = R_HEADS + "master";
  	private InMemoryRepository repo;
  	private TestRepository<InMemoryRepository> git;
  
  	@Before
  	public void setUp() throws IOException {
  		repo = new InMemoryRepository(new DfsRepositoryDescription("RefTree"));
  		git = new TestRepository<>(repo);
  	}
  
  	@Test
  	public void testEmptyTree() throws IOException {
  		RefTree tree = RefTree.newEmptyTree();
  		try (ObjectReader reader = repo.newObjectReader()) {
  			assertNull(HEAD, tree.exactRef(reader, HEAD));
  			assertNull("master", tree.exactRef(reader, R_MASTER));
 		}
 	}
 
 	@Test
 	public void testApplyThenReadMaster() throws Exception {
 		RefTree tree = RefTree.newEmptyTree();
 		RevBlob id = git.blob("A");
 		Command cmd = new Command(null, ref(R_MASTER, id));
 		assertTrue(tree.apply(Collections.singletonList(cmd)));
 		assertSame(NOT_ATTEMPTED, cmd.getResult());
 
 		try (ObjectReader reader = repo.newObjectReader()) {
 			Ref m = tree.exactRef(reader, R_MASTER);
 			assertNotNull(R_MASTER, m);
 			assertEquals(R_MASTER, m.getName());
 			assertEquals(id, m.getObjectId());
 			assertTrue("peeled", m.isPeeled());
 		}
 	}
 
 	@Test
 	public void testUpdateMaster() throws Exception {
 		RefTree tree = RefTree.newEmptyTree();
 		RevBlob id1 = git.blob("A");
 		Command cmd1 = new Command(null, ref(R_MASTER, id1));
 		assertTrue(tree.apply(Collections.singletonList(cmd1)));
 		assertSame(NOT_ATTEMPTED, cmd1.getResult());
 
 		RevBlob id2 = git.blob("B");
 		Command cmd2 = new Command(ref(R_MASTER, id1), ref(R_MASTER, id2));
 		assertTrue(tree.apply(Collections.singletonList(cmd2)));
 		assertSame(NOT_ATTEMPTED, cmd2.getResult());
 
 		try (ObjectReader reader = repo.newObjectReader()) {
 			Ref m = tree.exactRef(reader, R_MASTER);
 			assertNotNull(R_MASTER, m);
 			assertEquals(R_MASTER, m.getName());
 			assertEquals(id2, m.getObjectId());
 			assertTrue("peeled", m.isPeeled());
 		}
 	}
 
 	@Test
 	public void testHeadSymref() throws Exception {
 		RefTree tree = RefTree.newEmptyTree();
 		RevBlob id = git.blob("A");
 		Command cmd1 = new Command(null, ref(R_MASTER, id));
 		Command cmd2 = new Command(null, symref(HEAD, R_MASTER));
 		assertTrue(tree.apply(Arrays.asList(new Command[] { cmd1, cmd2 })));
 		assertSame(NOT_ATTEMPTED, cmd1.getResult());
 		assertSame(NOT_ATTEMPTED, cmd2.getResult());
 
 		try (ObjectReader reader = repo.newObjectReader()) {
 			Ref m = tree.exactRef(reader, HEAD);
 			assertNotNull(HEAD, m);
 			assertEquals(HEAD, m.getName());
 			assertTrue("symbolic", m.isSymbolic());
 			assertNotNull(m.getTarget());
 			assertEquals(R_MASTER, m.getTarget().getName());
 			assertEquals(id, m.getTarget().getObjectId());
 		}
 
 		// Writing flushes some buffers, re-read from blob.
 		ObjectId newId = write(tree);
 		try (ObjectReader reader = repo.newObjectReader();
 				RevWalk rw = new RevWalk(reader)) {
 			tree = RefTree.read(reader, rw.parseTree(newId));
 			Ref m = tree.exactRef(reader, HEAD);
 			assertEquals(R_MASTER, m.getTarget().getName());
 		}
 	}
 
 	@Test
 	public void testTagIsPeeled() throws Exception {
 		String name = "v1.0";
 		RefTree tree = RefTree.newEmptyTree();
 		RevBlob id = git.blob("A");
 		RevTag tag = git.tag(name, id);
 
 		String ref = R_TAGS + name;
 		Command cmd = create(ref, tag);
 		assertTrue(tree.apply(Collections.singletonList(cmd)));
 		assertSame(NOT_ATTEMPTED, cmd.getResult());
 
 		try (ObjectReader reader = repo.newObjectReader()) {
 			Ref m = tree.exactRef(reader, ref);
 			assertNotNull(ref, m);
 			assertEquals(ref, m.getName());
 			assertEquals(tag, m.getObjectId());
 			assertTrue("peeled", m.isPeeled());
 			assertEquals(id, m.getPeeledObjectId());
 		}
 	}
 
 	@Test
 	public void testApplyAlreadyExists() throws Exception {
 		RefTree tree = RefTree.newEmptyTree();
 		RevBlob a = git.blob("A");
 		Command cmd = new Command(null, ref(R_MASTER, a));
 		assertTrue(tree.apply(Collections.singletonList(cmd)));
 		ObjectId treeId = write(tree);
 
 		RevBlob b = git.blob("B");
 		Command cmd1 = create(R_MASTER, b);
 		Command cmd2 = create(R_MASTER, b);
 		assertFalse(tree.apply(Arrays.asList(new Command[] { cmd1, cmd2 })));
 		assertSame(LOCK_FAILURE, cmd1.getResult());
 		assertSame(REJECTED_OTHER_REASON, cmd2.getResult());
 		assertEquals(JGitText.get().transactionAborted, cmd2.getMessage());
 		assertEquals(treeId, write(tree));
 	}
 
 	@Test
 	public void testApplyWrongOldId() throws Exception {
 		RefTree tree = RefTree.newEmptyTree();
 		RevBlob a = git.blob("A");
 		Command cmd = new Command(null, ref(R_MASTER, a));
 		assertTrue(tree.apply(Collections.singletonList(cmd)));
 		ObjectId treeId = write(tree);
 
 		RevBlob b = git.blob("B");
 		RevBlob c = git.blob("C");
 		Command cmd1 = update(R_MASTER, b, c);
 		Command cmd2 = create(R_MASTER, b);
 		assertFalse(tree.apply(Arrays.asList(new Command[] { cmd1, cmd2 })));
 		assertSame(LOCK_FAILURE, cmd1.getResult());
 		assertSame(REJECTED_OTHER_REASON, cmd2.getResult());
 		assertEquals(JGitText.get().transactionAborted, cmd2.getMessage());
 		assertEquals(treeId, write(tree));
 	}
 
 	@Test
 	public void testApplyWrongOldIdButAlreadyCurrentIsNoOp() throws Exception {
 		RefTree tree = RefTree.newEmptyTree();
 		RevBlob a = git.blob("A");
 		Command cmd = new Command(null, ref(R_MASTER, a));
 		assertTrue(tree.apply(Collections.singletonList(cmd)));
 		ObjectId treeId = write(tree);
 
 		RevBlob b = git.blob("B");
 		cmd = update(R_MASTER, b, a);
 		assertTrue(tree.apply(Collections.singletonList(cmd)));
 		assertEquals(treeId, write(tree));
 	}
 
 	@Test
 	public void testApplyCannotCreateSubdirectory() throws Exception {
 		RefTree tree = RefTree.newEmptyTree();
 		RevBlob a = git.blob("A");
 		Command cmd = new Command(null, ref(R_MASTER, a));
 		assertTrue(tree.apply(Collections.singletonList(cmd)));
 		ObjectId treeId = write(tree);
 
 		RevBlob b = git.blob("B");
 		Command cmd1 = create(R_MASTER + "/fail", b);
 		assertFalse(tree.apply(Collections.singletonList(cmd1)));
 		assertSame(LOCK_FAILURE, cmd1.getResult());
 		assertEquals(treeId, write(tree));
 	}
 
 	@Test
 	public void testApplyCannotCreateParentRef() throws Exception {
 		RefTree tree = RefTree.newEmptyTree();
 		RevBlob a = git.blob("A");
 		Command cmd = new Command(null, ref(R_MASTER, a));
 		assertTrue(tree.apply(Collections.singletonList(cmd)));
 		ObjectId treeId = write(tree);
 
 		RevBlob b = git.blob("B");
 		Command cmd1 = create("refs/heads", b);
 		assertFalse(tree.apply(Collections.singletonList(cmd1)));
 		assertSame(LOCK_FAILURE, cmd1.getResult());
 		assertEquals(treeId, write(tree));
 	}
 
 	private static Ref ref(String name, ObjectId id) {
 		return new ObjectIdRef.PeeledNonTag(LOOSE, name, id);
 	}
 
 	private static Ref symref(String name, String dest) {
 		Ref d = new ObjectIdRef.PeeledNonTag(NEW, dest, null);
 		return new SymbolicRef(name, d);
 	}
 
 	private Command create(String name, ObjectId id)
 			throws MissingObjectException, IOException {
 		return update(name, ObjectId.zeroId(), id);
 	}
 
 	private Command update(String name, ObjectId oldId, ObjectId newId)
 			throws MissingObjectException, IOException {
 		try (RevWalk rw = new RevWalk(repo)) {
 			return new Command(rw, new ReceiveCommand(oldId, newId, name));
 		}
 	}
 
 	private ObjectId write(RefTree tree) throws IOException {
 		try (ObjectInserter ins = repo.newObjectInserter()) {
 			ObjectId id = tree.writeTree(ins);
 			ins.flush();
 			return id;
 		}
 	}
 }