Add CheckoutCommand

Add the ability to checkout a branch to the working tree.

Bug: 330860
Change-Id: Ie06b9e799a9e1be384da0b8996efa7209b32eac3
Signed-off-by: Chris Aniszczyk <caniszczyk@gmail.com>

5 files changed, 410 insertions, 0 deletions

diff --git a/org.eclipse.jgit.test/tst/org/eclipse/jgit/api/CheckoutCommandTest.java b/org.eclipse.jgit.test/tst/org/eclipse/jgit/api/CheckoutCommandTest.java
new file mode 100644
index 0000000000..295a284c02
--- /dev/null
+++ b/org.eclipse.jgit.test/tst/org/eclipse/jgit/api/CheckoutCommandTest.java
@@ -0,0 +1,123 @@
+/*
+ * Copyright (C) 2010, Chris Aniszczyk <caniszczyk@gmail.com>
+ * 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.api;
+
+import java.io.IOException;
+
+import org.eclipse.jgit.api.errors.InvalidRefNameException;
+import org.eclipse.jgit.api.errors.JGitInternalException;
+import org.eclipse.jgit.api.errors.RefAlreadyExistsException;
+import org.eclipse.jgit.api.errors.RefNotFoundException;
+import org.eclipse.jgit.lib.Constants;
+import org.eclipse.jgit.lib.RefUpdate;
+import org.eclipse.jgit.lib.RepositoryTestCase;
+import org.eclipse.jgit.revwalk.RevCommit;
+
+public class CheckoutCommandTest extends RepositoryTestCase {
+	private Git git;
+
+	RevCommit initialCommit;
+
+	RevCommit secondCommit;
+
+	@Override
+	protected void setUp() throws Exception {
+		super.setUp();
+		git = new Git(db);
+		// commit something
+		writeTrashFile("Test.txt", "Hello world");
+		git.add().addFilepattern("Test.txt").call();
+		initialCommit = git.commit().setMessage("Initial commit").call();
+
+		// create a master branch and switch to it
+		git.branchCreate().setName("test").call();
+		RefUpdate rup = db.updateRef(Constants.HEAD);
+		rup.link("refs/heads/test");
+
+		// commit something on the test branch
+		writeTrashFile("Test.txt", "Some change");
+		git.add().addFilepattern("Test.txt").call();
+		secondCommit = git.commit().setMessage("Second commit").call();
+	}
+
+	public void testSimpleCheckout() {
+		try {
+			git.checkout().setName("test").call();
+		} catch (Exception e) {
+			fail(e.getMessage());
+		}
+	}
+
+	public void testCheckout() {
+		try {
+			git.checkout().setName("test").call();
+			assertEquals("[Test.txt, mode:100644, content:Some change]",
+					indexState(CONTENT));
+			git.checkout().setName("master").call();
+			assertEquals("[Test.txt, mode:100644, content:Hello world]",
+					indexState(CONTENT));
+		} catch (Exception e) {
+			fail(e.getMessage());
+		}
+	}
+
+	public void testCreateBranchOnCheckout() throws IOException {
+		try {
+			git.checkout().setCreateBranch(true).setName("test2").call();
+		} catch (Exception e) {
+			fail(e.getMessage());
+		}
+		assertNotNull(db.getRef("test2"));
+	}
+
+	public void testCheckoutToNonExistingBranch() throws JGitInternalException,
+			RefAlreadyExistsException, InvalidRefNameException {
+		try {
+			git.checkout().setName("badbranch").call();
+			fail("Should have failed");
+		} catch (RefNotFoundException e) {
+			// except to hit here
+		}
+	}
+
+}
diff --git a/org.eclipse.jgit/resources/org/eclipse/jgit/JGitText.properties b/org.eclipse.jgit/resources/org/eclipse/jgit/JGitText.properties
index 4de5744c89..44f67ed1bf 100644
--- a/org.eclipse.jgit/resources/org/eclipse/jgit/JGitText.properties
+++ b/org.eclipse.jgit/resources/org/eclipse/jgit/JGitText.properties
@@ -79,6 +79,7 @@ channelMustBeInRange0_255=channel {0} must be in range [0, 255]
 characterClassIsNotSupported=The character class {0} is not supported.
 checkoutConflictWithFile=Checkout conflict with file: {0}
 checkoutConflictWithFiles=Checkout conflict with files: {0}
+checkoutUnexpectedResult=Checkout returned unexpected result {0}
 classCastNotA=Not a {0}
 collisionOn=Collision on {0}
 commandWasCalledInTheWrongState=Command {0} was called in the wrong state
diff --git a/org.eclipse.jgit/src/org/eclipse/jgit/JGitText.java b/org.eclipse.jgit/src/org/eclipse/jgit/JGitText.java
index 6ec8ed69ed..c24e5bb65a 100644
--- a/org.eclipse.jgit/src/org/eclipse/jgit/JGitText.java
+++ b/org.eclipse.jgit/src/org/eclipse/jgit/JGitText.java
@@ -137,6 +137,7 @@ public class JGitText extends TranslationBundle {
 	/***/ public String cantPassMeATree;
 	/***/ public String channelMustBeInRange0_255;
 	/***/ public String characterClassIsNotSupported;
+	/***/ public String checkoutUnexpectedResult;
 	/***/ public String checkoutConflictWithFile;
 	/***/ public String checkoutConflictWithFiles;
 	/***/ public String classCastNotA;
diff --git a/org.eclipse.jgit/src/org/eclipse/jgit/api/CheckoutCommand.java b/org.eclipse.jgit/src/org/eclipse/jgit/api/CheckoutCommand.java
new file mode 100644
index 0000000000..4e74a5460c
--- /dev/null
+++ b/org.eclipse.jgit/src/org/eclipse/jgit/api/CheckoutCommand.java
@@ -0,0 +1,272 @@
+/*
+ * Copyright (C) 2010, Chris Aniszczyk <caniszczyk@gmail.com>
+ * 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.api;
+
+import java.io.IOException;
+import java.text.MessageFormat;
+
+import org.eclipse.jgit.JGitText;
+import org.eclipse.jgit.api.errors.InvalidRefNameException;
+import org.eclipse.jgit.api.errors.JGitInternalException;
+import org.eclipse.jgit.api.errors.RefAlreadyExistsException;
+import org.eclipse.jgit.api.errors.RefNotFoundException;
+import org.eclipse.jgit.dircache.DirCacheCheckout;
+import org.eclipse.jgit.errors.AmbiguousObjectException;
+import org.eclipse.jgit.lib.Constants;
+import org.eclipse.jgit.lib.ObjectId;
+import org.eclipse.jgit.lib.Ref;
+import org.eclipse.jgit.lib.RefUpdate;
+import org.eclipse.jgit.lib.RefUpdate.Result;
+import org.eclipse.jgit.lib.Repository;
+import org.eclipse.jgit.revwalk.RevCommit;
+import org.eclipse.jgit.revwalk.RevWalk;
+
+/**
+ * Checkout a branch to the working tree
+ *
+ * @see <a
+ *      href="http://www.kernel.org/pub/software/scm/git/docs/git-checkout.html"
+ *      >Git documentation about Checkout</a>
+ */
+public class CheckoutCommand extends GitCommand<Ref> {
+	private String name;
+
+	private boolean force = false;
+
+	private boolean createBranch = false;
+
+	private CreateBranchCommand.SetupUpstreamMode upstreamMode;
+
+	private String startPoint = Constants.HEAD;
+
+	private RevCommit startCommit;
+
+	/**
+	 * @param repo
+	 */
+	protected CheckoutCommand(Repository repo) {
+		super(repo);
+	}
+
+	/**
+	 * @throws RefAlreadyExistsException
+	 *             when trying to create (without force) a branch with a name
+	 *             that already exists
+	 * @throws RefNotFoundException
+	 *             if the start point or branch can not be found
+	 * @throws InvalidRefNameException
+	 *             if the provided name is <code>null</code> or otherwise
+	 *             invalid
+	 * @return the newly created branch
+	 */
+	public Ref call() throws JGitInternalException, RefAlreadyExistsException,
+			RefNotFoundException, InvalidRefNameException {
+		checkCallable();
+		processOptions();
+		try {
+
+			if(createBranch) {
+				Git git = new Git(repo);
+				CreateBranchCommand command = git.branchCreate();
+				command.setName(name);
+				command.setStartPoint(getStartPoint().name());
+				if (upstreamMode != null)
+					command.setUpstreamMode(upstreamMode);
+				command.call();
+			}
+
+			RevWalk revWalk = new RevWalk(repo);
+			Ref headRef = repo.getRef(Constants.HEAD);
+			RevCommit headCommit = revWalk.parseCommit(headRef.getObjectId());
+			String refLogMessage = "checkout: moving from "
+					+ headRef.getTarget().getName();
+			ObjectId branch = repo.resolve(name);
+			Ref ref = repo.getRef(name);
+			if (branch == null)
+				throw new RefNotFoundException(MessageFormat.format(
+						JGitText.get().refNotResolved, name));
+
+			RevCommit newCommit = revWalk.parseCommit(branch);
+
+			DirCacheCheckout dco = new DirCacheCheckout(repo,
+					headCommit.getTree(), repo.lockDirCache(),
+					newCommit.getTree());
+			dco.setFailOnConflict(true);
+			dco.checkout();
+			RefUpdate refUpdate = repo.updateRef(Constants.HEAD);
+			refUpdate.setForceUpdate(force);
+			refUpdate.setRefLogMessage(
+					refLogMessage + "to " + newCommit.getName(), false);
+			Result updateResult = refUpdate.link(ref.getName());
+
+			setCallable(false);
+
+			boolean ok = false;
+			switch (updateResult) {
+			case NEW:
+				ok = true;
+				break;
+			case NO_CHANGE:
+			case FAST_FORWARD:
+			case FORCED:
+				ok = true;
+				break;
+			default:
+				break;
+			}
+
+			if (!ok)
+				throw new JGitInternalException(MessageFormat.format(
+						JGitText.get().checkoutUnexpectedResult,
+						updateResult
+						.name()));
+
+			Ref result = repo.getRef(name);
+
+			return result;
+		} catch (IOException ioe) {
+			throw new JGitInternalException(ioe.getMessage(), ioe);
+		}
+	}
+
+	private ObjectId getStartPoint() throws AmbiguousObjectException,
+			RefNotFoundException, IOException {
+		if (startCommit != null)
+			return startCommit.getId();
+		ObjectId result = null;
+		try {
+			result = repo.resolve((startPoint == null) ? Constants.HEAD
+					: startPoint);
+		} catch (AmbiguousObjectException e) {
+			throw e;
+		}
+		if (result == null)
+			throw new RefNotFoundException(MessageFormat.format(
+					JGitText.get().refNotResolved,
+					startPoint != null ? startPoint : Constants.HEAD));
+		return result;
+	}
+
+	private void processOptions() throws InvalidRefNameException {
+		if (name == null
+				|| !Repository.isValidRefName(Constants.R_HEADS + name))
+			throw new InvalidRefNameException(MessageFormat.format(JGitText
+					.get().branchNameInvalid, name == null ? "<null>" : name));
+	}
+
+	/**
+	 * @param name
+	 *            the name of the new branch
+	 * @return this instance
+	 */
+	public CheckoutCommand setName(String name) {
+		checkCallable();
+		this.name = name;
+		return this;
+	}
+
+	/**
+	 * @param createBranch
+	 *            if <code>true</code> a branch will be created as part of the
+	 *            checkout and set to the specified start point
+	 * @return this instance
+	 */
+	public CheckoutCommand setCreateBranch(boolean createBranch) {
+		checkCallable();
+		this.createBranch = createBranch;
+		return this;
+	}
+
+	/**
+	 * @param force
+	 *            if <code>true</code> and the branch with the given name
+	 *            already exists, the start-point of an existing branch will be
+	 *            set to a new start-point; if false, the existing branch will
+	 *            not be changed
+	 * @return this instance
+	 */
+	public CheckoutCommand setForce(boolean force) {
+		checkCallable();
+		this.force = force;
+		return this;
+	}
+
+	/**
+	 * @param startPoint
+	 *            corresponds to the start-point option; if <code>null</code>,
+	 *            the current HEAD will be used
+	 * @return this instance
+	 */
+	public CheckoutCommand setStartPoint(String startPoint) {
+		checkCallable();
+		this.startPoint = startPoint;
+		this.startCommit = null;
+		return this;
+	}
+
+	/**
+	 * @param startCommit
+	 *            corresponds to the start-point option; if <code>null</code>,
+	 *            the current HEAD will be used
+	 * @return this instance
+	 */
+	public CheckoutCommand setStartPoint(RevCommit startCommit) {
+		checkCallable();
+		this.startCommit = startCommit;
+		this.startPoint = null;
+		return this;
+	}
+
+	/**
+	 * @param mode
+	 *            corresponds to the --track/--no-track options; may be
+	 *            <code>null</code>
+	 * @return this instance
+	 */
+	public CheckoutCommand setUpstreamMode(
+			CreateBranchCommand.SetupUpstreamMode mode) {
+		checkCallable();
+		this.upstreamMode = mode;
+		return this;
+	}
+}
diff --git a/org.eclipse.jgit/src/org/eclipse/jgit/api/Git.java b/org.eclipse.jgit/src/org/eclipse/jgit/api/Git.java
index 3bcdfc7aa8..8623bb76a4 100644
--- a/org.eclipse.jgit/src/org/eclipse/jgit/api/Git.java
+++ b/org.eclipse.jgit/src/org/eclipse/jgit/api/Git.java
@@ -270,6 +270,19 @@ public class Git {
 	}
 
 	/**
+	 * Returns a command object to execute a {@code checkout} command
+	 *
+	 * @see <a
+	 *      href="http://www.kernel.org/pub/software/scm/git/docs/git-checkout.html"
+	 *      >Git documentation about checkout</a>
+	 * @return a {@link CheckoutCommand} used to collect all optional parameters
+	 *         and to finally execute the {@code checkout} command
+	 */
+	public CheckoutCommand checkout() {
+		return new CheckoutCommand(repo);
+	}
+
+	/**
 	 * @return the git repository this class is interacting with
 	 */
 	public Repository getRepository() {