Command line: implement checkout -- <path>

Change-Id: I3d261e6541fe0fcaa210587d2aa226e153071351
Signed-off-by: Matthias Sohn <matthias.sohn@sap.com>

org.eclipse.jgit.pgm.test/src/org/eclipse/jgit/lib/CLIRepositoryTestCase.java

@@ -81,6 +81,10 @@ public class CLIRepositoryTestCase extends LocalDiskRepositoryTestCase {
 		return JGitTestUtil.writeTrashFile(db, name, data);
 	}
 
+	protected String read(final File file) throws IOException {
+		return JGitTestUtil.read(file);
+	}
+
 	protected void deleteTrashFile(final String name) throws IOException {
 		JGitTestUtil.deleteTrashFile(db, name);
 	}

org.eclipse.jgit.pgm.test/tst/org/eclipse/jgit/pgm/CheckoutTest.java

@@ -42,6 +42,8 @@
  */
 package org.eclipse.jgit.pgm;
 
+import static org.junit.Assert.assertArrayEquals;
+
 import java.io.File;
 
 import org.eclipse.jgit.api.Git;
@@ -191,4 +193,26 @@ public class CheckoutTest extends CLIRepositoryTestCase {
 						: actual.length);
 		Assert.assertEquals(expected, actual[0]);
 	}
+
+	@Test
+	public void testCheckoutPath() throws Exception {
+		Git git = new Git(db);
+		writeTrashFile("a", "Hello world a");
+		git.add().addFilepattern(".").call();
+		git.commit().setMessage("commit file a").call();
+		git.branchCreate().setName("branch_1").call();
+		git.checkout().setName("branch_1").call();
+		File b = writeTrashFile("b", "Hello world b");
+		git.add().addFilepattern("b").call();
+		git.commit().setMessage("commit file b").call();
+		File a = writeTrashFile("a", "New Hello world a");
+		git.add().addFilepattern(".").call();
+		git.commit().setMessage("modified a").call();
+		assertArrayEquals(new String[] { "" },
+				execute("git checkout HEAD~2 -- a"));
+		assertEquals("Hello world a", read(a));
+		assertArrayEquals(new String[] { "* branch_1", "  master", "" },
+				execute("git branch"));
+		assertEquals("Hello world b", read(b));
+	}
 }

org.eclipse.jgit.pgm/src/org/eclipse/jgit/pgm/Checkout.java

@@ -45,6 +45,8 @@
 package org.eclipse.jgit.pgm;
 
 import java.text.MessageFormat;
+import java.util.ArrayList;
+import java.util.List;
 
 import org.eclipse.jgit.api.CheckoutCommand;
 import org.eclipse.jgit.api.Git;
@@ -58,6 +60,7 @@ import org.eclipse.jgit.lib.Repository;
 import org.eclipse.jgit.pgm.internal.CLIText;
 import org.kohsuke.args4j.Argument;
 import org.kohsuke.args4j.Option;
+import org.kohsuke.args4j.spi.StopOptionHandler;
 
 @Command(common = true, usage = "usage_checkout")
 class Checkout extends TextBuiltin {
@@ -68,9 +71,13 @@ class Checkout extends TextBuiltin {
 	@Option(name = "--force", aliases = { "-f" }, usage = "usage_forceCheckout")
 	private boolean force = false;
 
-	@Argument(required = true, metaVar = "metaVar_name", usage = "usage_checkout")
+	@Argument(required = true, index = 0, metaVar = "metaVar_name", usage = "usage_checkout")
 	private String name;
 
+	@Argument(index = 1)
+	@Option(name = "--", metaVar = "metaVar_paths", multiValued = true, handler = StopOptionHandler.class)
+	private List<String> paths = new ArrayList<String>();
+
 	@Override
 	protected void run() throws Exception {
 		if (createBranch) {
@@ -80,9 +87,15 @@ class Checkout extends TextBuiltin {
 		}
 
 		CheckoutCommand command = new Git(db).checkout();
+		if (paths.size() > 0) {
+			command.setStartPoint(name);
+			for (String path : paths)
+				command.addPath(path);
+		} else {
 			command.setCreateBranch(createBranch);
 			command.setName(name);
 			command.setForce(force);
+		}
 		try {
 			String oldBranch = db.getBranch();
 			Ref ref = command.call();