Add path support to checkout command.

Change-Id: I89e8edfc6dd87d5bf8fd08704df2432720084330
Signed-off-by: Kevin Sawicki <kevin@github.com>

1 files changed, 84 insertions, 3 deletions

diff --git a/org.eclipse.jgit/src/org/eclipse/jgit/api/CheckoutCommand.java b/org.eclipse.jgit/src/org/eclipse/jgit/api/CheckoutCommand.java
index 16c1fcfa33..f3a2e53602 100644
--- a/org.eclipse.jgit/src/org/eclipse/jgit/api/CheckoutCommand.java
+++ b/org.eclipse.jgit/src/org/eclipse/jgit/api/CheckoutCommand.java
@@ -43,8 +43,11 @@
  */
 package org.eclipse.jgit.api;
 
+import java.io.File;
 import java.io.IOException;
 import java.text.MessageFormat;
+import java.util.LinkedList;
+import java.util.List;
 
 import org.eclipse.jgit.JGitText;
 import org.eclipse.jgit.api.CheckoutResult.Status;
@@ -52,7 +55,12 @@ 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.DirCache;
 import org.eclipse.jgit.dircache.DirCacheCheckout;
+import org.eclipse.jgit.dircache.DirCacheEditor;
+import org.eclipse.jgit.dircache.DirCacheEditor.PathEdit;
+import org.eclipse.jgit.dircache.DirCacheEntry;
+import org.eclipse.jgit.dircache.DirCacheIterator;
 import org.eclipse.jgit.errors.AmbiguousObjectException;
 import org.eclipse.jgit.errors.CheckoutConflictException;
 import org.eclipse.jgit.lib.AnyObjectId;
@@ -65,6 +73,8 @@ import org.eclipse.jgit.lib.Repository;
 import org.eclipse.jgit.revwalk.RevCommit;
 import org.eclipse.jgit.revwalk.RevTree;
 import org.eclipse.jgit.revwalk.RevWalk;
+import org.eclipse.jgit.treewalk.TreeWalk;
+import org.eclipse.jgit.treewalk.filter.PathFilterGroup;
 
 /**
  * Checkout a branch to the working tree
@@ -82,17 +92,20 @@ public class CheckoutCommand extends GitCommand<Ref> {
 
 	private CreateBranchCommand.SetupUpstreamMode upstreamMode;
 
-	private String startPoint = Constants.HEAD;
+	private String startPoint = null;
 
 	private RevCommit startCommit;
 
 	private CheckoutResult status;
 
+	private List<String> paths;
+
 	/**
 	 * @param repo
 	 */
 	protected CheckoutCommand(Repository repo) {
 		super(repo);
+		this.paths = new LinkedList<String>();
 	}
 
 	/**
@@ -111,6 +124,12 @@ public class CheckoutCommand extends GitCommand<Ref> {
 		checkCallable();
 		processOptions();
 		try {
+			if (!paths.isEmpty()) {
+				checkoutPaths();
+				status = CheckoutResult.OK_RESULT;
+				setCallable(false);
+				return null;
+			}
 
 			if (createBranch) {
 				Git git = new Git(repo);
@@ -196,6 +215,67 @@ public class CheckoutCommand extends GitCommand<Ref> {
 		}
 	}
 
+	/**
+	 * @param path
+	 *            Path to update in the working tree and index.
+	 * @return {@code this}
+	 */
+	public CheckoutCommand addPath(String path) {
+		checkCallable();
+		this.paths.add(path);
+		return this;
+	}
+
+	/**
+	 * Checkout paths into index and working directory
+	 *
+	 * @return this instance
+	 * @throws IOException
+	 * @throws RefNotFoundException
+	 */
+	protected CheckoutCommand checkoutPaths() throws IOException,
+			RefNotFoundException {
+		RevWalk revWalk = new RevWalk(repo);
+		DirCache dc = repo.lockDirCache();
+		try {
+			TreeWalk treeWalk = new TreeWalk(revWalk.getObjectReader());
+			treeWalk.setRecursive(true);
+			treeWalk.addTree(new DirCacheIterator(dc));
+			treeWalk.setFilter(PathFilterGroup.createFromStrings(paths));
+			List<String> files = new LinkedList<String>();
+			while (treeWalk.next())
+				files.add(treeWalk.getPathString());
+
+			if (startCommit != null || startPoint != null) {
+				DirCacheEditor editor = dc.editor();
+				TreeWalk startWalk = new TreeWalk(revWalk.getObjectReader());
+				startWalk.setRecursive(true);
+				startWalk.setFilter(treeWalk.getFilter());
+				startWalk.addTree(revWalk.parseCommit(getStartPoint())
+						.getTree());
+				while (startWalk.next()) {
+					final ObjectId blobId = startWalk.getObjectId(0);
+					editor.add(new PathEdit(startWalk.getPathString()) {
+
+						public void apply(DirCacheEntry ent) {
+							ent.setObjectId(blobId);
+						}
+					});
+				}
+				editor.commit();
+			}
+
+			File workTree = repo.getWorkTree();
+			for (String file : files)
+				DirCacheCheckout.checkoutEntry(repo, new File(workTree, file),
+						dc.getEntry(file));
+		} finally {
+			dc.unlock();
+			revWalk.release();
+		}
+		return this;
+	}
+
 	private ObjectId getStartPoint() throws AmbiguousObjectException,
 			RefNotFoundException, IOException {
 		if (startCommit != null)
@@ -215,8 +295,9 @@ public class CheckoutCommand extends GitCommand<Ref> {
 	}
 
 	private void processOptions() throws InvalidRefNameException {
-		if (name == null
-				|| !Repository.isValidRefName(Constants.R_HEADS + name))
+		if (paths.isEmpty()
+				&& (name == null || !Repository
+						.isValidRefName(Constants.R_HEADS + name)))
 			throw new InvalidRefNameException(MessageFormat.format(JGitText
 					.get().branchNameInvalid, name == null ? "<null>" : name));
 	}