/*
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    * and other copyright owners as documented in the project's IP log.
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    * This program and the accompanying materials are made available
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    * accompanies this distribution, is reproduced below, and is
    * available at http://www.eclipse.org/org/documents/edl-v10.php
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  package org.eclipse.jgit.treewalk;
  
  import static java.nio.charset.StandardCharsets.UTF_8;
  import static org.junit.Assert.assertEquals;
  import static org.junit.Assert.assertFalse;
  import static org.junit.Assert.assertNotNull;
  import static org.junit.Assert.assertTrue;
  import static org.junit.Assume.assumeNoException;
  
  import java.io.File;
  import java.io.IOException;
  import java.nio.file.InvalidPathException;
  import java.security.MessageDigest;
  import java.time.Instant;
  
  import org.eclipse.jgit.api.Git;
  import org.eclipse.jgit.api.ResetCommand.ResetType;
  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.CorruptObjectException;
  import org.eclipse.jgit.errors.IncorrectObjectTypeException;
  import org.eclipse.jgit.errors.MissingObjectException;
  import org.eclipse.jgit.junit.JGitTestUtil;
  import org.eclipse.jgit.junit.RepositoryTestCase;
  import org.eclipse.jgit.lib.ConfigConstants;
  import org.eclipse.jgit.lib.Constants;
  import org.eclipse.jgit.lib.FileMode;
  import org.eclipse.jgit.lib.ObjectId;
  import org.eclipse.jgit.lib.ObjectInserter;
  import org.eclipse.jgit.lib.ObjectReader;
  import org.eclipse.jgit.lib.Repository;
  import org.eclipse.jgit.revwalk.RevCommit;
  import org.eclipse.jgit.storage.file.FileRepositoryBuilder;
  import org.eclipse.jgit.treewalk.WorkingTreeIterator.MetadataDiff;
  import org.eclipse.jgit.treewalk.filter.PathFilter;
  import org.eclipse.jgit.util.FS;
  import org.eclipse.jgit.util.FileUtils;
  import org.eclipse.jgit.util.RawParseUtils;
  import org.junit.Before;
  import org.junit.Test;
  
  public class FileTreeIteratorTest extends RepositoryTestCase {
  	private final String[] paths = { "a,", "a,b", "a/b", "a0b" };
  
  	private Instant[] mtime;
  
  	@Override
  	@Before
  	public void setUp() throws Exception {
  		super.setUp();
  
  		// We build the entries backwards so that on POSIX systems we
 		// are likely to get the entries in the trash directory in the
 		// opposite order of what they should be in for the iteration.
 		// This should stress the sorting code better than doing it in
 		// the correct order.
 		//
 		mtime = new Instant[paths.length];
 		for (int i = paths.length - 1; i >= 0; i--) {
 			final String s = paths[i];
 			writeTrashFile(s, s);
 			mtime[i] = db.getFS().lastModifiedInstant(new File(trash, s));
 		}
 	}
 
 	@Test
 	public void testGetEntryContentLength() throws Exception {
 		final FileTreeIterator fti = new FileTreeIterator(db);
 		fti.next(1);
 		assertEquals(3, fti.getEntryContentLength());
 		fti.back(1);
 		assertEquals(2, fti.getEntryContentLength());
 		fti.next(1);
 		assertEquals(3, fti.getEntryContentLength());
 		fti.reset();
 		assertEquals(2, fti.getEntryContentLength());
 	}
 
 	@Test
 	public void testEmptyIfRootIsFile() throws Exception {
 		final File r = new File(trash, paths[0]);
 		assertTrue(r.isFile());
 		final FileTreeIterator fti = new FileTreeIterator(r, db.getFS(),
 				db.getConfig().get(WorkingTreeOptions.KEY));
 		assertTrue(fti.first());
 		assertTrue(fti.eof());
 	}
 
 	@Test
 	public void testEmptyIfRootDoesNotExist() throws Exception {
 		final File r = new File(trash, "not-existing-file");
 		assertFalse(r.exists());
 		final FileTreeIterator fti = new FileTreeIterator(r, db.getFS(),
 				db.getConfig().get(WorkingTreeOptions.KEY));
 		assertTrue(fti.first());
 		assertTrue(fti.eof());
 	}
 
 	@Test
 	public void testEmptyIfRootIsEmpty() throws Exception {
 		final File r = new File(trash, "not-existing-file");
 		assertFalse(r.exists());
 		FileUtils.mkdir(r);
 
 		final FileTreeIterator fti = new FileTreeIterator(r, db.getFS(),
 				db.getConfig().get(WorkingTreeOptions.KEY));
 		assertTrue(fti.first());
 		assertTrue(fti.eof());
 	}
 
 	@Test
 	public void testEmptyIteratorOnEmptyDirectory() throws Exception {
 		String nonExistingFileName = "not-existing-file";
 		final File r = new File(trash, nonExistingFileName);
 		assertFalse(r.exists());
 		FileUtils.mkdir(r);
 
 		final FileTreeIterator parent = new FileTreeIterator(db);
 
 		while (!parent.getEntryPathString().equals(nonExistingFileName))
 			parent.next(1);
 
 		final FileTreeIterator childIter = new FileTreeIterator(parent, r,
 				db.getFS());
 		assertTrue(childIter.first());
 		assertTrue(childIter.eof());
 
 		String parentPath = parent.getEntryPathString();
 		assertEquals(nonExistingFileName, parentPath);
 
 		// must be "not-existing-file/", but getEntryPathString() was broken by
 		// 445363 too
 		String childPath = childIter.getEntryPathString();
 
 		// in bug 445363 the iterator wrote garbage to the parent "path" field
 		EmptyTreeIterator e = childIter.createEmptyTreeIterator();
 		assertNotNull(e);
 
 		// check if parent path is not overridden by empty iterator (bug 445363)
 		// due bug 445363 this was "/ot-existing-file" instead of
 		// "not-existing-file"
 		assertEquals(parentPath, parent.getEntryPathString());
 		assertEquals(parentPath + "/", childPath);
 		assertEquals(parentPath + "/", childIter.getEntryPathString());
 		assertEquals(childPath + "/", e.getEntryPathString());
 	}
 
 	@Test
 	public void testSimpleIterate() throws Exception {
 		final FileTreeIterator top = new FileTreeIterator(trash, db.getFS(),
 				db.getConfig().get(WorkingTreeOptions.KEY));
 
 		assertTrue(top.first());
 		assertFalse(top.eof());
 		assertEquals(FileMode.REGULAR_FILE.getBits(), top.mode);
 		assertEquals(paths[0], nameOf(top));
 		assertEquals(paths[0].length(), top.getEntryLength());
 		assertEquals(mtime[0], top.getEntryLastModifiedInstant());
 
 		top.next(1);
 		assertFalse(top.first());
 		assertFalse(top.eof());
 		assertEquals(FileMode.REGULAR_FILE.getBits(), top.mode);
 		assertEquals(paths[1], nameOf(top));
 		assertEquals(paths[1].length(), top.getEntryLength());
 		assertEquals(mtime[1], top.getEntryLastModifiedInstant());
 
 		top.next(1);
 		assertFalse(top.first());
 		assertFalse(top.eof());
 		assertEquals(FileMode.TREE.getBits(), top.mode);
 
 		final ObjectReader reader = db.newObjectReader();
 		final AbstractTreeIterator sub = top.createSubtreeIterator(reader);
 		assertTrue(sub instanceof FileTreeIterator);
 		final FileTreeIterator subfti = (FileTreeIterator) sub;
 		assertTrue(sub.first());
 		assertFalse(sub.eof());
 		assertEquals(paths[2], nameOf(sub));
 		assertEquals(paths[2].length(), subfti.getEntryLength());
 		assertEquals(mtime[2], subfti.getEntryLastModifiedInstant());
 
 		sub.next(1);
 		assertTrue(sub.eof());
 
 		top.next(1);
 		assertFalse(top.first());
 		assertFalse(top.eof());
 		assertEquals(FileMode.REGULAR_FILE.getBits(), top.mode);
 		assertEquals(paths[3], nameOf(top));
 		assertEquals(paths[3].length(), top.getEntryLength());
 		assertEquals(mtime[3], top.getEntryLastModifiedInstant());
 
 		top.next(1);
 		assertTrue(top.eof());
 	}
 
 	@Test
 	public void testComputeFileObjectId() throws Exception {
 		final FileTreeIterator top = new FileTreeIterator(trash, db.getFS(),
 				db.getConfig().get(WorkingTreeOptions.KEY));
 
 		final MessageDigest md = Constants.newMessageDigest();
 		md.update(Constants.encodeASCII(Constants.TYPE_BLOB));
 		md.update((byte) ' ');
 		md.update(Constants.encodeASCII(paths[0].length()));
 		md.update((byte) 0);
 		md.update(Constants.encode(paths[0]));
 		final ObjectId expect = ObjectId.fromRaw(md.digest());
 
 		assertEquals(expect, top.getEntryObjectId());
 
 		// Verify it was cached by removing the file and getting it again.
 		//
 		FileUtils.delete(new File(trash, paths[0]));
 		assertEquals(expect, top.getEntryObjectId());
 	}
 
 	@Test
 	public void testDirCacheMatchingId() throws Exception {
 		File f = writeTrashFile("file", "content");
 		try (Git git = new Git(db)) {
 			writeTrashFile("file", "content");
 			fsTick(f);
 			git.add().addFilepattern("file").call();
 		}
 		DirCacheEntry dce = db.readDirCache().getEntry("file");
 		TreeWalk tw = new TreeWalk(db);
 		FileTreeIterator fti = new FileTreeIterator(trash, db.getFS(), db
 				.getConfig().get(WorkingTreeOptions.KEY));
 		tw.addTree(fti);
 		DirCacheIterator dci = new DirCacheIterator(db.readDirCache());
 		tw.addTree(dci);
 		fti.setDirCacheIterator(tw, 1);
 		while (tw.next() && !tw.getPathString().equals("file")) {
 			//
 		}
 		assertEquals(MetadataDiff.EQUAL, fti.compareMetadata(dce));
 		ObjectId fromRaw = ObjectId.fromRaw(fti.idBuffer(), fti.idOffset());
 		assertEquals("6b584e8ece562ebffc15d38808cd6b98fc3d97ea",
 				fromRaw.getName());
 		try (ObjectReader objectReader = db.newObjectReader()) {
 			assertFalse(fti.isModified(dce, false, objectReader));
 		}
 	}
 
 	@Test
 	public void testTreewalkEnterSubtree() throws Exception {
 		try (Git git = new Git(db); TreeWalk tw = new TreeWalk(db)) {
 			writeTrashFile("b/c", "b/c");
 			writeTrashFile("z/.git", "gitdir: /tmp/somewhere");
 			git.add().addFilepattern(".").call();
 			git.rm().addFilepattern("a,").addFilepattern("a,b")
 					.addFilepattern("a0b").call();
 			assertEquals("[a/b, mode:100644][b/c, mode:100644][z, mode:160000]",
 					indexState(0));
 			FileUtils.delete(new File(db.getWorkTree(), "b"),
 					FileUtils.RECURSIVE);
 
 			tw.addTree(new DirCacheIterator(db.readDirCache()));
 			tw.addTree(new FileTreeIterator(db));
 			assertTrue(tw.next());
 			assertEquals("a", tw.getPathString());
 			tw.enterSubtree();
 			tw.next();
 			assertEquals("a/b", tw.getPathString());
 			tw.next();
 			assertEquals("b", tw.getPathString());
 			tw.enterSubtree();
 			tw.next();
 			assertEquals("b/c", tw.getPathString());
 			assertNotNull(tw.getTree(0, AbstractTreeIterator.class));
 			assertNotNull(tw.getTree(EmptyTreeIterator.class));
 		}
 	}
 
 	@Test
 	public void testIsModifiedSymlinkAsFile() throws Exception {
 		writeTrashFile("symlink", "content");
 		try (Git git = new Git(db)) {
 			db.getConfig().setString(ConfigConstants.CONFIG_CORE_SECTION, null,
 					ConfigConstants.CONFIG_KEY_SYMLINKS, "false");
 			git.add().addFilepattern("symlink").call();
 			git.commit().setMessage("commit").call();
 		}
 
 		// Modify previously committed DirCacheEntry and write it back to disk
 		DirCacheEntry dce = db.readDirCache().getEntry("symlink");
 		dce.setFileMode(FileMode.SYMLINK);
 		try (ObjectReader objectReader = db.newObjectReader()) {
 			DirCacheCheckout.checkoutEntry(db, dce, objectReader, false, null);
 
 			FileTreeIterator fti = new FileTreeIterator(trash, db.getFS(),
 					db.getConfig().get(WorkingTreeOptions.KEY));
 			while (!fti.getEntryPathString().equals("symlink"))
 				fti.next(1);
 			assertFalse(fti.isModified(dce, false, objectReader));
 		}
 	}
 
 	@Test
 	public void testIsModifiedFileSmudged() throws Exception {
 		File f = writeTrashFile("file", "content");
 		FS fs = db.getFS();
 		try (Git git = new Git(db)) {
 			// The idea of this test is to check the smudged handling
 			// Hopefully fsTick will make sure our entry gets smudged
 			fsTick(f);
 			writeTrashFile("file", "content");
 			Instant lastModified = fs.lastModifiedInstant(f);
 			git.add().addFilepattern("file").call();
 			writeTrashFile("file", "conten2");
 			fs.setLastModified(f.toPath(), lastModified);
 			// We cannot trust this to go fast enough on
 			// a system with less than one-second lastModified
 			// resolution, so we force the index to have the
 			// same timestamp as the file we look at.
 			fs.setLastModified(db.getIndexFile().toPath(), lastModified);
 		}
 		DirCacheEntry dce = db.readDirCache().getEntry("file");
 		FileTreeIterator fti = new FileTreeIterator(trash, db.getFS(), db
 				.getConfig().get(WorkingTreeOptions.KEY));
 		while (!fti.getEntryPathString().equals("file"))
 			fti.next(1);
 		// If the rounding trick does not work we could skip the compareMetaData
 		// test and hope that we are usually testing the intended code path.
 		assertEquals(MetadataDiff.SMUDGED, fti.compareMetadata(dce));
 		try (ObjectReader objectReader = db.newObjectReader()) {
 			assertTrue(fti.isModified(dce, false, objectReader));
 		}
 	}
 
 	@Test
 	public void submoduleHeadMatchesIndex() throws Exception {
 		try (Git git = new Git(db);
 				TreeWalk walk = new TreeWalk(db)) {
 			writeTrashFile("file.txt", "content");
 			git.add().addFilepattern("file.txt").call();
 			final RevCommit id = git.commit().setMessage("create file").call();
 			final String path = "sub";
 			DirCache cache = db.lockDirCache();
 			DirCacheEditor editor = cache.editor();
 			editor.add(new PathEdit(path) {
 
 				@Override
 				public void apply(DirCacheEntry ent) {
 					ent.setFileMode(FileMode.GITLINK);
 					ent.setObjectId(id);
 				}
 			});
 			editor.commit();
 
 			Git.cloneRepository().setURI(db.getDirectory().toURI().toString())
 					.setDirectory(new File(db.getWorkTree(), path)).call()
 					.getRepository().close();
 
 			DirCacheIterator indexIter = new DirCacheIterator(db.readDirCache());
 			FileTreeIterator workTreeIter = new FileTreeIterator(db);
 			walk.addTree(indexIter);
 			walk.addTree(workTreeIter);
 			walk.setFilter(PathFilter.create(path));
 
 			assertTrue(walk.next());
 			assertTrue(indexIter.idEqual(workTreeIter));
 		}
 	}
 
 	@Test
 	public void submoduleWithNoGitDirectory() throws Exception {
 		try (Git git = new Git(db);
 				TreeWalk walk = new TreeWalk(db)) {
 			writeTrashFile("file.txt", "content");
 			git.add().addFilepattern("file.txt").call();
 			final RevCommit id = git.commit().setMessage("create file").call();
 			final String path = "sub";
 			DirCache cache = db.lockDirCache();
 			DirCacheEditor editor = cache.editor();
 			editor.add(new PathEdit(path) {
 
 				@Override
 				public void apply(DirCacheEntry ent) {
 					ent.setFileMode(FileMode.GITLINK);
 					ent.setObjectId(id);
 				}
 			});
 			editor.commit();
 
 			File submoduleRoot = new File(db.getWorkTree(), path);
 			assertTrue(submoduleRoot.mkdir());
 			assertTrue(new File(submoduleRoot, Constants.DOT_GIT).mkdir());
 
 			DirCacheIterator indexIter = new DirCacheIterator(db.readDirCache());
 			FileTreeIterator workTreeIter = new FileTreeIterator(db);
 			walk.addTree(indexIter);
 			walk.addTree(workTreeIter);
 			walk.setFilter(PathFilter.create(path));
 
 			assertTrue(walk.next());
 			assertFalse(indexIter.idEqual(workTreeIter));
 			assertEquals(ObjectId.zeroId(), workTreeIter.getEntryObjectId());
 		}
 	}
 
 	@Test
 	public void submoduleWithNoHead() throws Exception {
 		try (Git git = new Git(db);
 				TreeWalk walk = new TreeWalk(db)) {
 			writeTrashFile("file.txt", "content");
 			git.add().addFilepattern("file.txt").call();
 			final RevCommit id = git.commit().setMessage("create file").call();
 			final String path = "sub";
 			DirCache cache = db.lockDirCache();
 			DirCacheEditor editor = cache.editor();
 			editor.add(new PathEdit(path) {
 
 				@Override
 				public void apply(DirCacheEntry ent) {
 					ent.setFileMode(FileMode.GITLINK);
 					ent.setObjectId(id);
 				}
 			});
 			editor.commit();
 
 			assertNotNull(Git.init().setDirectory(new File(db.getWorkTree(), path))
 					.call().getRepository());
 
 			DirCacheIterator indexIter = new DirCacheIterator(db.readDirCache());
 			FileTreeIterator workTreeIter = new FileTreeIterator(db);
 			walk.addTree(indexIter);
 			walk.addTree(workTreeIter);
 			walk.setFilter(PathFilter.create(path));
 
 			assertTrue(walk.next());
 			assertFalse(indexIter.idEqual(workTreeIter));
 			assertEquals(ObjectId.zeroId(), workTreeIter.getEntryObjectId());
 		}
 	}
 
 	@Test
 	public void submoduleDirectoryIterator() throws Exception {
 		try (Git git = new Git(db);
 				TreeWalk walk = new TreeWalk(db)) {
 			writeTrashFile("file.txt", "content");
 			git.add().addFilepattern("file.txt").call();
 			final RevCommit id = git.commit().setMessage("create file").call();
 			final String path = "sub";
 			DirCache cache = db.lockDirCache();
 			DirCacheEditor editor = cache.editor();
 			editor.add(new PathEdit(path) {
 
 				@Override
 				public void apply(DirCacheEntry ent) {
 					ent.setFileMode(FileMode.GITLINK);
 					ent.setObjectId(id);
 				}
 			});
 			editor.commit();
 
 			Git.cloneRepository().setURI(db.getDirectory().toURI().toString())
 					.setDirectory(new File(db.getWorkTree(), path)).call()
 					.getRepository().close();
 
 			DirCacheIterator indexIter = new DirCacheIterator(db.readDirCache());
 			FileTreeIterator workTreeIter = new FileTreeIterator(db.getWorkTree(),
 					db.getFS(), db.getConfig().get(WorkingTreeOptions.KEY));
 			walk.addTree(indexIter);
 			walk.addTree(workTreeIter);
 			walk.setFilter(PathFilter.create(path));
 
 			assertTrue(walk.next());
 			assertTrue(indexIter.idEqual(workTreeIter));
 		}
 	}
 
 	@Test
 	public void submoduleNestedWithHeadMatchingIndex() throws Exception {
 		try (Git git = new Git(db);
 				TreeWalk walk = new TreeWalk(db)) {
 			writeTrashFile("file.txt", "content");
 			git.add().addFilepattern("file.txt").call();
 			final RevCommit id = git.commit().setMessage("create file").call();
 			final String path = "sub/dir1/dir2";
 			DirCache cache = db.lockDirCache();
 			DirCacheEditor editor = cache.editor();
 			editor.add(new PathEdit(path) {
 
 				@Override
 				public void apply(DirCacheEntry ent) {
 					ent.setFileMode(FileMode.GITLINK);
 					ent.setObjectId(id);
 				}
 			});
 			editor.commit();
 
 			Git.cloneRepository().setURI(db.getDirectory().toURI().toString())
 					.setDirectory(new File(db.getWorkTree(), path)).call()
 					.getRepository().close();
 
 			DirCacheIterator indexIter = new DirCacheIterator(db.readDirCache());
 			FileTreeIterator workTreeIter = new FileTreeIterator(db);
 			walk.addTree(indexIter);
 			walk.addTree(workTreeIter);
 			walk.setFilter(PathFilter.create(path));
 
 			assertTrue(walk.next());
 			assertTrue(indexIter.idEqual(workTreeIter));
 		}
 	}
 
 	@Test
 	public void idOffset() throws Exception {
 		try (Git git = new Git(db);
 				TreeWalk tw = new TreeWalk(db)) {
 			writeTrashFile("fileAinfsonly", "A");
 			File fileBinindex = writeTrashFile("fileBinindex", "B");
 			fsTick(fileBinindex);
 			git.add().addFilepattern("fileBinindex").call();
 			writeTrashFile("fileCinfsonly", "C");
 			DirCacheIterator indexIter = new DirCacheIterator(db.readDirCache());
 			FileTreeIterator workTreeIter = new FileTreeIterator(db);
 			tw.addTree(indexIter);
 			tw.addTree(workTreeIter);
 			workTreeIter.setDirCacheIterator(tw, 0);
 			assertEntry("d46c305e85b630558ee19cc47e73d2e5c8c64cdc", "a,", tw);
 			assertEntry("58ee403f98538ec02409538b3f80adf610accdec", "a,b", tw);
 			assertEntry("0000000000000000000000000000000000000000", "a", tw);
 			assertEntry("b8d30ff397626f0f1d3538d66067edf865e201d6", "a0b", tw);
 			// The reason for adding this test. Check that the id is correct for
 			// mixed
 			assertEntry("8c7e5a667f1b771847fe88c01c3de34413a1b220",
 					"fileAinfsonly", tw);
 			assertEntry("7371f47a6f8bd23a8fa1a8b2a9479cdd76380e54", "fileBinindex",
 					tw);
 			assertEntry("96d80cd6c4e7158dbebd0849f4fb7ce513e5828c",
 					"fileCinfsonly", tw);
 			assertFalse(tw.next());
 		}
 	}
 
 	private final FileTreeIterator.FileModeStrategy NO_GITLINKS_STRATEGY =
 			new FileTreeIterator.FileModeStrategy() {
 				@Override
 				public FileMode getMode(File f, FS.Attributes attributes) {
 					if (attributes.isSymbolicLink()) {
 						return FileMode.SYMLINK;
 					} else if (attributes.isDirectory()) {
 						// NOTE: in the production DefaultFileModeStrategy, there is
 						// a check here for a subdirectory called '.git', and if it
 						// exists, we create a GITLINK instead of recursing into the
 						// tree.  In this custom strategy, we ignore nested git dirs
 						// and treat all directories the same.
 						return FileMode.TREE;
 					} else if (attributes.isExecutable()) {
 						return FileMode.EXECUTABLE_FILE;
 					} else {
 						return FileMode.REGULAR_FILE;
 					}
 				}
 			};
 
 	private Repository createNestedRepo() throws IOException {
 		File gitdir = createUniqueTestGitDir(false);
 		FileRepositoryBuilder builder = new FileRepositoryBuilder();
 		builder.setGitDir(gitdir);
 		Repository nestedRepo = builder.build();
 		nestedRepo.create();
 
 		JGitTestUtil.writeTrashFile(nestedRepo, "sub", "a.txt", "content");
 
 		File nestedRepoPath = new File(nestedRepo.getWorkTree(), "sub/nested");
 		FileRepositoryBuilder nestedBuilder = new FileRepositoryBuilder();
 		nestedBuilder.setWorkTree(nestedRepoPath);
 		nestedBuilder.build().create();
 
 		JGitTestUtil.writeTrashFile(nestedRepo, "sub/nested", "b.txt",
 				"content b");
 
 		return nestedRepo;
 	}
 
 	@Test
 	public void testCustomFileModeStrategy() throws Exception {
 		Repository nestedRepo = createNestedRepo();
 
 		try (Git git = new Git(nestedRepo)) {
 			// validate that our custom strategy is honored
 			WorkingTreeIterator customIterator = new FileTreeIterator(
 					nestedRepo, NO_GITLINKS_STRATEGY);
 			git.add().setWorkingTreeIterator(customIterator).addFilepattern(".")
 					.call();
 			assertEquals(
 					"[sub/a.txt, mode:100644, content:content]"
 							+ "[sub/nested/b.txt, mode:100644, content:content b]",
 					indexState(nestedRepo, CONTENT));
 		}
 	}
 
 	@Test
 	public void testCustomFileModeStrategyFromParentIterator() throws Exception {
 		Repository nestedRepo = createNestedRepo();
 
 		try (Git git = new Git(nestedRepo)) {
 			FileTreeIterator customIterator = new FileTreeIterator(nestedRepo,
 					NO_GITLINKS_STRATEGY);
 			File r = new File(nestedRepo.getWorkTree(), "sub");
 
 			// here we want to validate that if we create a new iterator using
 			// the constructor that accepts a parent iterator, that the child
 			// iterator correctly inherits the FileModeStrategy from the parent
 			// iterator.
 			FileTreeIterator childIterator = new FileTreeIterator(
 					customIterator, r, nestedRepo.getFS());
 			git.add().setWorkingTreeIterator(childIterator).addFilepattern(".")
 					.call();
 			assertEquals(
 					"[sub/a.txt, mode:100644, content:content]"
 							+ "[sub/nested/b.txt, mode:100644, content:content b]",
 					indexState(nestedRepo, CONTENT));
 		}
 	}
 
 	@Test
 	public void testFileModeSymLinkIsNotATree() throws IOException {
 		org.junit.Assume.assumeTrue(FS.DETECTED.supportsSymlinks());
 		FS fs = db.getFS();
 		// mål = target in swedish, just to get some unicode in here
 		writeTrashFile("mål/data", "targetdata");
 		File file = new File(trash, "länk");
 
 		try {
 			file.toPath();
 		} catch (InvalidPathException e) {
 			// When executing a test with LANG environment variable set to non
 			// UTF-8 encoding, it seems that JRE cannot handle Unicode file
 			// paths. This happens when this test is executed in Bazel as it
 			// unsets LANG
 			// (https://docs.bazel.build/versions/master/test-encyclopedia.html#initial-conditions).
 			// Skip the test if the runtime cannot handle Unicode characters.
 			assumeNoException(e);
 		}
 
 		fs.createSymLink(file, "mål");
 		FileTreeIterator fti = new FileTreeIterator(db);
 		assertFalse(fti.eof());
 		while (!fti.getEntryPathString().equals("länk")) {
 			fti.next(1);
 		}
 		assertEquals("länk", fti.getEntryPathString());
 		assertEquals(FileMode.SYMLINK, fti.getEntryFileMode());
 		fti.next(1);
 		assertFalse(fti.eof());
 		assertEquals("mål", fti.getEntryPathString());
 		assertEquals(FileMode.TREE, fti.getEntryFileMode());
 		fti.next(1);
 		assertTrue(fti.eof());
 	}
 
 	@Test
 	public void testSymlinkNotModifiedThoughNormalized() throws Exception {
 		DirCache dc = db.lockDirCache();
 		DirCacheEditor dce = dc.editor();
 		final String UNNORMALIZED = "target/";
 		final byte[] UNNORMALIZED_BYTES = Constants.encode(UNNORMALIZED);
 		try (ObjectInserter oi = db.newObjectInserter()) {
 			final ObjectId linkid = oi.insert(Constants.OBJ_BLOB,
 					UNNORMALIZED_BYTES, 0, UNNORMALIZED_BYTES.length);
 			dce.add(new DirCacheEditor.PathEdit("link") {
 				@Override
 				public void apply(DirCacheEntry ent) {
 					ent.setFileMode(FileMode.SYMLINK);
 					ent.setObjectId(linkid);
 					ent.setLength(UNNORMALIZED_BYTES.length);
 				}
 			});
 			assertTrue(dce.commit());
 		}
 		try (Git git = new Git(db)) {
 			git.commit().setMessage("Adding link").call();
 			git.reset().setMode(ResetType.HARD).call();
 			DirCacheIterator dci = new DirCacheIterator(db.readDirCache());
 			FileTreeIterator fti = new FileTreeIterator(db);
 
 			// self-check
 			while (!fti.getEntryPathString().equals("link")) {
 				fti.next(1);
 			}
 			assertEquals("link", fti.getEntryPathString());
 			assertEquals("link", dci.getEntryPathString());
 
 			// test
 			assertFalse(fti.isModified(dci.getDirCacheEntry(), true,
 					db.newObjectReader()));
 		}
 	}
 
 	/**
 	 * Like #testSymlinkNotModifiedThoughNormalized but there is no
 	 * normalization being done.
 	 *
 	 * @throws Exception
 	 */
 	@Test
 	public void testSymlinkModifiedNotNormalized() throws Exception {
 		DirCache dc = db.lockDirCache();
 		DirCacheEditor dce = dc.editor();
 		final String NORMALIZED = "target";
 		final byte[] NORMALIZED_BYTES = Constants.encode(NORMALIZED);
 		try (ObjectInserter oi = db.newObjectInserter()) {
 			final ObjectId linkid = oi.insert(Constants.OBJ_BLOB,
 					NORMALIZED_BYTES, 0, NORMALIZED_BYTES.length);
 			dce.add(new DirCacheEditor.PathEdit("link") {
 				@Override
 				public void apply(DirCacheEntry ent) {
 					ent.setFileMode(FileMode.SYMLINK);
 					ent.setObjectId(linkid);
 					ent.setLength(NORMALIZED_BYTES.length);
 				}
 			});
 			assertTrue(dce.commit());
 		}
 		try (Git git = new Git(db)) {
 			git.commit().setMessage("Adding link").call();
 			git.reset().setMode(ResetType.HARD).call();
 			DirCacheIterator dci = new DirCacheIterator(db.readDirCache());
 			FileTreeIterator fti = new FileTreeIterator(db);
 
 			// self-check
 			while (!fti.getEntryPathString().equals("link")) {
 				fti.next(1);
 			}
 			assertEquals("link", fti.getEntryPathString());
 			assertEquals("link", dci.getEntryPathString());
 
 			// test
 			assertFalse(fti.isModified(dci.getDirCacheEntry(), true,
 					db.newObjectReader()));
 		}
 	}
 
 	/**
 	 * Like #testSymlinkNotModifiedThoughNormalized but here the link is
 	 * modified.
 	 *
 	 * @throws Exception
 	 */
 	@Test
 	public void testSymlinkActuallyModified() throws Exception {
 		org.junit.Assume.assumeTrue(FS.DETECTED.supportsSymlinks());
 		final String NORMALIZED = "target";
 		final byte[] NORMALIZED_BYTES = Constants.encode(NORMALIZED);
 		try (ObjectInserter oi = db.newObjectInserter()) {
 			final ObjectId linkid = oi.insert(Constants.OBJ_BLOB,
 					NORMALIZED_BYTES, 0, NORMALIZED_BYTES.length);
 			DirCache dc = db.lockDirCache();
 			DirCacheEditor dce = dc.editor();
 			dce.add(new DirCacheEditor.PathEdit("link") {
 				@Override
 				public void apply(DirCacheEntry ent) {
 					ent.setFileMode(FileMode.SYMLINK);
 					ent.setObjectId(linkid);
 					ent.setLength(NORMALIZED_BYTES.length);
 				}
 			});
 			assertTrue(dce.commit());
 		}
 		try (Git git = new Git(db)) {
 			git.commit().setMessage("Adding link").call();
 			git.reset().setMode(ResetType.HARD).call();
 
 			FileUtils.delete(new File(trash, "link"), FileUtils.NONE);
 			FS.DETECTED.createSymLink(new File(trash, "link"), "newtarget");
 			DirCacheIterator dci = new DirCacheIterator(db.readDirCache());
 			FileTreeIterator fti = new FileTreeIterator(db);
 
 			// self-check
 			while (!fti.getEntryPathString().equals("link")) {
 				fti.next(1);
 			}
 			assertEquals("link", fti.getEntryPathString());
 			assertEquals("link", dci.getEntryPathString());
 
 			// test
 			assertTrue(fti.isModified(dci.getDirCacheEntry(), true,
 					db.newObjectReader()));
 		}
 	}
 
 	private static void assertEntry(String sha1string, String path, TreeWalk tw)
 			throws MissingObjectException, IncorrectObjectTypeException,
 			CorruptObjectException, IOException {
 		assertTrue(tw.next());
 		assertEquals(path, tw.getPathString());
 		assertEquals(sha1string, tw.getObjectId(1).getName() /* 1=filetree here */);
 	}
 
 	private static String nameOf(AbstractTreeIterator i) {
 		return RawParseUtils.decode(UTF_8, i.path, 0, i.pathLen);
 	}
 }