Add ListTagCommand to JGit API

Bug: 355246
Change-Id: I11e019f3c19b4340ac7160ac8fcbadd52499d322
Signed-off-by: Chris Aniszczyk <caniszczyk@gmail.com>

org.eclipse.jgit.test/tst/org/eclipse/jgit/api/TagCommandTest.java

@@ -197,4 +197,40 @@ public class TagCommandTest extends RepositoryTestCase {
 		assertEquals(0, deleted.size());
 	}
 
+	@Test
+	public void testShouldNotBlowUpIfThereAreNoTagsInRepository()
+			throws Exception {
+		Git git = new Git(db);
+		git.add().addFilepattern("*").call();
+		git.commit().setMessage("initial commit").call();
+		List<RevTag> list = git.tagList().call();
+		assertEquals(0, list.size());
+	}
+
+	@Test
+	public void testShouldNotBlowUpIfThereAreNoCommitsInRepository()
+			throws Exception {
+		Git git = new Git(db);
+		List<RevTag> list = git.tagList().call();
+		assertEquals(0, list.size());
+	}
+
+	@Test
+	public void testListAllTagsInRepositoryInOrder() throws Exception {
+		Git git = new Git(db);
+		git.add().addFilepattern("*").call();
+		git.commit().setMessage("initial commit").call();
+
+		git.tag().setName("v3").call();
+		git.tag().setName("v2").call();
+		git.tag().setName("v10").call();
+
+		List<RevTag> list = git.tagList().call();
+
+		assertEquals(3, list.size());
+		assertEquals("v10", list.get(0).getTagName());
+		assertEquals("v2", list.get(1).getTagName());
+		assertEquals("v3", list.get(2).getTagName());
+	}
+
 }

org.eclipse.jgit/src/org/eclipse/jgit/api/Git.java

@@ -241,6 +241,16 @@ public class Git {
 		return new ListBranchCommand(repo);
 	}
 
+	/**
+	 *
+	 * Returns a command object used to list tags
+	 *
+	 * @return a {@link ListTagCommand}
+	 */
+	public ListTagCommand tagList() {
+		return new ListTagCommand(repo);
+	}
+
 	/**
 	 * Returns a command object used to rename branches
 	 *
@@ -496,8 +506,8 @@ public class Git {
 
 	/**
 	 * Returns a command object used to delete tags
-	 *
-	 * @return a {@link DeleteBranchCommand}
+	 * 
+	 * @return a {@link DeleteTagCommand}
 	 */
 	public DeleteTagCommand tagDelete() {
 		return new DeleteTagCommand(repo);

org.eclipse.jgit/src/org/eclipse/jgit/api/ListTagCommand.java

@@ -0,0 +1,104 @@
+/*
+ * Copyright (C) 2011, Ketan Padegaonkar <ketanpadegaonkar@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.util.ArrayList;
+import java.util.Collections;
+import java.util.Comparator;
+import java.util.List;
+import java.util.Map;
+
+import org.eclipse.jgit.api.errors.JGitInternalException;
+import org.eclipse.jgit.lib.Constants;
+import org.eclipse.jgit.lib.Ref;
+import org.eclipse.jgit.lib.Repository;
+import org.eclipse.jgit.revwalk.RevTag;
+import org.eclipse.jgit.revwalk.RevWalk;
+
+/**
+ * Used to obtain a list of tags.
+ *
+ * @see <a href="http://www.kernel.org/pub/software/scm/git/docs/git-tag.html"
+ *      >Git documentation about Tag</a>
+ */
+public class ListTagCommand extends GitCommand<List<RevTag>> {
+
+	/**
+	 * @param repo
+	 */
+	protected ListTagCommand(Repository repo) {
+		super(repo);
+	}
+
+	/**
+	 * @throws JGitInternalException
+	 *             upon internal failure
+	 * @return the tags available
+	 */
+	public List<RevTag> call() throws JGitInternalException {
+		checkCallable();
+		Map<String, Ref> refList;
+		List<RevTag> tags = new ArrayList<RevTag>();
+		RevWalk revWalk = new RevWalk(repo);
+		try {
+			refList = repo.getRefDatabase().getRefs(Constants.R_TAGS);
+			for (Ref ref : refList.values()) {
+				RevTag tag = revWalk.parseTag(ref.getObjectId());
+				tags.add(tag);
+			}
+		} catch (IOException e) {
+			throw new JGitInternalException(e.getMessage(), e);
+		} finally {
+			revWalk.release();
+		}
+		Collections.sort(tags, new Comparator<RevTag>() {
+			public int compare(RevTag o1, RevTag o2) {
+				return o1.getTagName().compareTo(o2.getTagName());
+			}
+		});
+		setCallable(false);
+		return tags;
+	}
+
+}