Support remote aliases in repo manifest.

Change-Id: Icbe5761b9d8a4ae5305bfe45b2d042f214156fc8
Signed-off-by: Yuxuan 'fishy' Wang <fishywang@google.com>

org.eclipse.jgit.test/tst/org/eclipse/jgit/gitrepo/RepoCommandTest.java

@@ -641,6 +641,30 @@ public class RepoCommandTest extends RepositoryTestCase {
 		assertTrue("We should have bar", file.exists());
 	}
 
+	@Test
+	public void testRemoteAlias() throws Exception {
+		StringBuilder xmlContent = new StringBuilder();
+		xmlContent.append("<?xml version=\"1.0\" encoding=\"UTF-8\"?>\n")
+			.append("<manifest>")
+			.append("<remote name=\"remote1\" fetch=\".\" alias=\"remote2\" />")
+			.append("<default revision=\"master\" remote=\"remote2\" />")
+			.append("<project path=\"foo\" name=\"")
+			.append(defaultUri)
+			.append("\" />")
+			.append("</manifest>");
+
+		Repository localDb = createWorkRepository();
+		JGitTestUtil.writeTrashFile(
+				localDb, "manifest.xml", xmlContent.toString());
+		RepoCommand command = new RepoCommand(localDb);
+		command
+			.setPath(localDb.getWorkTree().getAbsolutePath() + "/manifest.xml")
+			.setURI(rootUri)
+			.call();
+		File file = new File(localDb.getWorkTree(), "foo/hello.txt");
+		assertTrue("We should have foo", file.exists());
+	}
+
 	private void resolveRelativeUris() {
 		// Find the longest common prefix ends with "/" as rootUri.
 		defaultUri = defaultDb.getDirectory().toURI().toString();

org.eclipse.jgit/src/org/eclipse/jgit/gitrepo/RepoCommand.java

@@ -407,8 +407,11 @@ public class RepoCommand extends GitCommand<RevCommit> {
 						attributes.getValue("remote"), //$NON-NLS-1$
 						attributes.getValue("groups")); //$NON-NLS-1$
 			} else if ("remote".equals(qName)) { //$NON-NLS-1$
-				remotes.put(attributes.getValue("name"), //$NON-NLS-1$
-						attributes.getValue("fetch")); //$NON-NLS-1$
+				String alias = attributes.getValue("alias"); //$NON-NLS-1$
+				String fetch = attributes.getValue("fetch"); //$NON-NLS-1$
+				remotes.put(attributes.getValue("name"), fetch); //$NON-NLS-1$
+				if (alias != null)
+					remotes.put(alias, fetch);
 			} else if ("default".equals(qName)) { //$NON-NLS-1$
 				defaultRemote = attributes.getValue("remote"); //$NON-NLS-1$
 				defaultRevision = attributes.getValue("revision"); //$NON-NLS-1$