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1   /*
2    * Copyright (C) 2008, Shawn O. Pearce <spearce@spearce.org>
3    * Copyright (C) 2010, Christian Halstrick <christian.halstrick@sap.com>
4    * Copyright (C) 2010, Matthias Sohn <matthias.sohn@sap.com>
5    * Copyright (C) 2012-2021, Robin Rosenberg and others
6    *
7    * This program and the accompanying materials are made available under the
8    * terms of the Eclipse Distribution License v. 1.0 which is available at
9    * https://www.eclipse.org/org/documents/edl-v10.php.
10   *
11   * SPDX-License-Identifier: BSD-3-Clause
12   */
13  
14  package org.eclipse.jgit.treewalk;
15  
16  import static java.nio.charset.StandardCharsets.UTF_8;
17  
18  import java.io.ByteArrayInputStream;
19  import java.io.File;
20  import java.io.FileInputStream;
21  import java.io.FileNotFoundException;
22  import java.io.IOException;
23  import java.io.InputStream;
24  import java.nio.ByteBuffer;
25  import java.nio.CharBuffer;
26  import java.nio.charset.CharacterCodingException;
27  import java.nio.charset.CharsetEncoder;
28  import java.nio.file.Path;
29  import java.text.MessageFormat;
30  import java.time.Instant;
31  import java.util.Arrays;
32  import java.util.Collections;
33  import java.util.Comparator;
34  import java.util.HashMap;
35  import java.util.Map;
36  
37  import org.eclipse.jgit.api.errors.FilterFailedException;
38  import org.eclipse.jgit.attributes.AttributesNode;
39  import org.eclipse.jgit.attributes.AttributesRule;
40  import org.eclipse.jgit.attributes.FilterCommand;
41  import org.eclipse.jgit.attributes.FilterCommandRegistry;
42  import org.eclipse.jgit.diff.RawText;
43  import org.eclipse.jgit.dircache.DirCacheEntry;
44  import org.eclipse.jgit.dircache.DirCacheIterator;
45  import org.eclipse.jgit.errors.CorruptObjectException;
46  import org.eclipse.jgit.errors.LargeObjectException;
47  import org.eclipse.jgit.errors.MissingObjectException;
48  import org.eclipse.jgit.errors.NoWorkTreeException;
49  import org.eclipse.jgit.ignore.FastIgnoreRule;
50  import org.eclipse.jgit.ignore.IgnoreNode;
51  import org.eclipse.jgit.internal.JGitText;
52  import org.eclipse.jgit.lib.ConfigConstants;
53  import org.eclipse.jgit.lib.Constants;
54  import org.eclipse.jgit.lib.CoreConfig.CheckStat;
55  import org.eclipse.jgit.lib.CoreConfig.EolStreamType;
56  import org.eclipse.jgit.lib.CoreConfig.SymLinks;
57  import org.eclipse.jgit.lib.FileMode;
58  import org.eclipse.jgit.lib.ObjectId;
59  import org.eclipse.jgit.lib.ObjectLoader;
60  import org.eclipse.jgit.lib.ObjectReader;
61  import org.eclipse.jgit.lib.Repository;
62  import org.eclipse.jgit.submodule.SubmoduleWalk;
63  import org.eclipse.jgit.treewalk.TreeWalk.OperationType;
64  import org.eclipse.jgit.util.FS;
65  import org.eclipse.jgit.util.FS.ExecutionResult;
66  import org.eclipse.jgit.util.FileUtils;
67  import org.eclipse.jgit.util.Holder;
68  import org.eclipse.jgit.util.IO;
69  import org.eclipse.jgit.util.Paths;
70  import org.eclipse.jgit.util.RawParseUtils;
71  import org.eclipse.jgit.util.TemporaryBuffer;
72  import org.eclipse.jgit.util.TemporaryBuffer.LocalFile;
73  import org.eclipse.jgit.util.io.EolStreamTypeUtil;
74  import org.eclipse.jgit.util.sha1.SHA1;
75  
76  /**
77   * Walks a working directory tree as part of a
78   * {@link org.eclipse.jgit.treewalk.TreeWalk}.
79   * <p>
80   * Most applications will want to use the standard implementation of this
81   * iterator, {@link org.eclipse.jgit.treewalk.FileTreeIterator}, as that does
82   * all IO through the standard <code>java.io</code> package. Plugins for a Java
83   * based IDE may however wish to create their own implementations of this class
84   * to allow traversal of the IDE's project space, as well as benefit from any
85   * caching the IDE may have.
86   *
87   * @see FileTreeIterator
88   */
89  public abstract class WorkingTreeIterator extends AbstractTreeIterator {
90  	private static final int MAX_EXCEPTION_TEXT_SIZE = 10 * 1024;
91  
92  	/** An empty entry array, suitable for {@link #init(Entry[])}. */
93  	protected static final Entry[] EOF = {};
94  
95  	/** Size we perform file IO in if we have to read and hash a file. */
96  	static final int BUFFER_SIZE = 2048;
97  
98  	/**
99  	 * Maximum size of files which may be read fully into memory for performance
100 	 * reasons.
101 	 */
102 	private static final long MAXIMUM_FILE_SIZE_TO_READ_FULLY = 65536;
103 
104 	/** Inherited state of this iterator, describing working tree, etc. */
105 	private final IteratorState state;
106 
107 	/** The {@link #idBuffer()} for the current entry. */
108 	private byte[] contentId;
109 
110 	/** Index within {@link #entries} that {@link #contentId} came from. */
111 	private int contentIdFromPtr;
112 
113 	/** List of entries obtained from the subclass. */
114 	private Entry[] entries;
115 
116 	/** Total number of entries in {@link #entries} that are valid. */
117 	private int entryCnt;
118 
119 	/** Current position within {@link #entries}. */
120 	private int ptr;
121 
122 	/** If there is a .gitignore file present, the parsed rules from it. */
123 	private IgnoreNode ignoreNode;
124 
125 	/**
126 	 * cached clean filter command. Use a Ref in order to distinguish between
127 	 * the ref not cached yet and the value null
128 	 */
129 	private Holder<String> cleanFilterCommandHolder;
130 
131 	/**
132 	 * cached eol stream type. Use a Ref in order to distinguish between the ref
133 	 * not cached yet and the value null
134 	 */
135 	private Holder<EolStreamType> eolStreamTypeHolder;
136 
137 	/** Repository that is the root level being iterated over */
138 	protected Repository repository;
139 
140 	/** Cached canonical length, initialized from {@link #idBuffer()} */
141 	private long canonLen = -1;
142 
143 	/** The offset of the content id in {@link #idBuffer()} */
144 	private int contentIdOffset;
145 
146 	/** A comparator for {@link Instant}s. */
147 	private final InstantComparator timestampComparator = new InstantComparator();
148 
149 	/**
150 	 * Create a new iterator with no parent.
151 	 *
152 	 * @param options
153 	 *            working tree options to be used
154 	 */
155 	protected WorkingTreeIterator(WorkingTreeOptions options) {
156 		super();
157 		state = new IteratorState(options);
158 	}
159 
160 	/**
161 	 * Create a new iterator with no parent and a prefix.
162 	 * <p>
163 	 * The prefix path supplied is inserted in front of all paths generated by
164 	 * this iterator. It is intended to be used when an iterator is being
165 	 * created for a subsection of an overall repository and needs to be
166 	 * combined with other iterators that are created to run over the entire
167 	 * repository namespace.
168 	 *
169 	 * @param prefix
170 	 *            position of this iterator in the repository tree. The value
171 	 *            may be null or the empty string to indicate the prefix is the
172 	 *            root of the repository. A trailing slash ('/') is
173 	 *            automatically appended if the prefix does not end in '/'.
174 	 * @param options
175 	 *            working tree options to be used
176 	 */
177 	protected WorkingTreeIterator(final String prefix,
178 			WorkingTreeOptions options) {
179 		super(prefix);
180 		state = new IteratorState(options);
181 	}
182 
183 	/**
184 	 * Create an iterator for a subtree of an existing iterator.
185 	 *
186 	 * @param p
187 	 *            parent tree iterator.
188 	 */
189 	protected WorkingTreeIterator(WorkingTreeIterator p) {
190 		super(p);
191 		state = p.state;
192 		repository = p.repository;
193 	}
194 
195 	/**
196 	 * Initialize this iterator for the root level of a repository.
197 	 * <p>
198 	 * This method should only be invoked after calling {@link #init(Entry[])},
199 	 * and only for the root iterator.
200 	 *
201 	 * @param repo
202 	 *            the repository.
203 	 */
204 	protected void initRootIterator(Repository repo) {
205 		repository = repo;
206 		Entry entry;
207 		if (ignoreNode instanceof PerDirectoryIgnoreNode)
208 			entry = ((PerDirectoryIgnoreNode) ignoreNode).entry;
209 		else
210 			entry = null;
211 		ignoreNode = new RootIgnoreNode(entry, repo);
212 	}
213 
214 	/**
215 	 * Define the matching {@link org.eclipse.jgit.dircache.DirCacheIterator},
216 	 * to optimize ObjectIds.
217 	 *
218 	 * Once the DirCacheIterator has been set this iterator must only be
219 	 * advanced by the TreeWalk that is supplied, as it assumes that itself and
220 	 * the corresponding DirCacheIterator are positioned on the same file path
221 	 * whenever {@link #idBuffer()} is invoked.
222 	 *
223 	 * @param walk
224 	 *            the walk that will be advancing this iterator.
225 	 * @param treeId
226 	 *            index of the matching
227 	 *            {@link org.eclipse.jgit.dircache.DirCacheIterator}.
228 	 */
229 	public void setDirCacheIterator(TreeWalk walk, int treeId) {
230 		state.walk = walk;
231 		state.dirCacheTree = treeId;
232 	}
233 
234 	/**
235 	 * Retrieves the {@link DirCacheIterator} at the current entry if
236 	 * {@link #setDirCacheIterator(TreeWalk, int)} was called.
237 	 *
238 	 * @return the DirCacheIterator, or {@code null} if not set or not at the
239 	 *         current entry
240 	 * @since 5.0
241 	 */
242 	protected DirCacheIterator getDirCacheIterator() {
243 		if (state.dirCacheTree >= 0 && state.walk != null) {
244 			return state.walk.getTree(state.dirCacheTree,
245 					DirCacheIterator.class);
246 		}
247 		return null;
248 	}
249 
250 	/**
251 	 * Defines whether this {@link WorkingTreeIterator} walks ignored
252 	 * directories.
253 	 *
254 	 * @param includeIgnored
255 	 *            {@code false} to skip ignored directories, if possible;
256 	 *            {@code true} to always include them in the walk
257 	 * @since 5.0
258 	 */
259 	public void setWalkIgnoredDirectories(boolean includeIgnored) {
260 		state.walkIgnored = includeIgnored;
261 	}
262 
263 	/**
264 	 * Tells whether this {@link WorkingTreeIterator} walks ignored directories.
265 	 *
266 	 * @return {@code true} if it does, {@code false} otherwise
267 	 * @since 5.0
268 	 */
269 	public boolean walksIgnoredDirectories() {
270 		return state.walkIgnored;
271 	}
272 
273 	/** {@inheritDoc} */
274 	@Override
275 	public boolean hasId() {
276 		if (contentIdFromPtr == ptr)
277 			return true;
278 		return (mode & FileMode.TYPE_MASK) == FileMode.TYPE_FILE;
279 	}
280 
281 	/** {@inheritDoc} */
282 	@Override
283 	public byte[] idBuffer() {
284 		if (contentIdFromPtr == ptr)
285 			return contentId;
286 
287 		if (state.walk != null) {
288 			// If there is a matching DirCacheIterator, we can reuse
289 			// its idBuffer, but only if we appear to be clean against
290 			// the cached index information for the path.
291 			DirCacheIterator i = state.walk.getTree(state.dirCacheTree,
292 							DirCacheIterator.class);
293 			if (i != null) {
294 				DirCacheEntry ent = i.getDirCacheEntry();
295 				if (ent != null && compareMetadata(ent) == MetadataDiff.EQUAL
296 						&& ((ent.getFileMode().getBits()
297 								& FileMode.TYPE_MASK) != FileMode.TYPE_GITLINK)) {
298 					contentIdOffset = i.idOffset();
299 					contentIdFromPtr = ptr;
300 					return contentId = i.idBuffer();
301 				}
302 				contentIdOffset = 0;
303 			} else {
304 				contentIdOffset = 0;
305 			}
306 		}
307 		switch (mode & FileMode.TYPE_MASK) {
308 		case FileMode.TYPE_SYMLINK:
309 		case FileMode.TYPE_FILE:
310 			contentIdFromPtr = ptr;
311 			return contentId = idBufferBlob(entries[ptr]);
312 		case FileMode.TYPE_GITLINK:
313 			contentIdFromPtr = ptr;
314 			return contentId = idSubmodule(entries[ptr]);
315 		}
316 		return zeroid;
317 	}
318 
319 	/** {@inheritDoc} */
320 	@Override
321 	public boolean isWorkTree() {
322 		return true;
323 	}
324 
325 	/**
326 	 * Get submodule id for given entry.
327 	 *
328 	 * @param e
329 	 *            a {@link org.eclipse.jgit.treewalk.WorkingTreeIterator.Entry}
330 	 *            object.
331 	 * @return non-null submodule id
332 	 */
333 	protected byte[] idSubmodule(Entry e) {
334 		if (repository == null)
335 			return zeroid;
336 		File directory;
337 		try {
338 			directory = repository.getWorkTree();
339 		} catch (NoWorkTreeException nwte) {
340 			return zeroid;
341 		}
342 		return idSubmodule(directory, e);
343 	}
344 
345 	/**
346 	 * Get submodule id using the repository at the location of the entry
347 	 * relative to the directory.
348 	 *
349 	 * @param directory
350 	 *            a {@link java.io.File} object.
351 	 * @param e
352 	 *            a {@link org.eclipse.jgit.treewalk.WorkingTreeIterator.Entry}
353 	 *            object.
354 	 * @return non-null submodule id
355 	 */
356 	protected byte[] idSubmodule(File directory, Entry e) {
357 		try (Repository submoduleRepo = SubmoduleWalk.getSubmoduleRepository(
358 				directory, e.getName(),
359 				repository != null ? repository.getFS() : FS.DETECTED)) {
360 			if (submoduleRepo == null) {
361 				return zeroid;
362 			}
363 			ObjectId head = submoduleRepo.resolve(Constants.HEAD);
364 			if (head == null) {
365 				return zeroid;
366 			}
367 			byte[] id = new byte[Constants.OBJECT_ID_LENGTH];
368 			head.copyRawTo(id, 0);
369 			return id;
370 		} catch (IOException exception) {
371 			return zeroid;
372 		}
373 	}
374 
375 	private static final byte[] digits = { '0', '1', '2', '3', '4', '5', '6',
376 			'7', '8', '9' };
377 
378 	private static final byte[] hblob = Constants
379 			.encodedTypeString(Constants.OBJ_BLOB);
380 
381 	private byte[] idBufferBlob(Entry e) {
382 		try {
383 			final InputStream is = e.openInputStream();
384 			if (is == null)
385 				return zeroid;
386 			try {
387 				state.initializeReadBuffer();
388 
389 				final long len = e.getLength();
390 				InputStream filteredIs = possiblyFilteredInputStream(e, is, len,
391 						OperationType.CHECKIN_OP);
392 				return computeHash(filteredIs, canonLen);
393 			} finally {
394 				safeClose(is);
395 			}
396 		} catch (IOException err) {
397 			// Can't read the file? Don't report the failure either.
398 			return zeroid;
399 		}
400 	}
401 
402 	private InputStream possiblyFilteredInputStream(final Entry e,
403 			final InputStream is, final long len) throws IOException {
404 		return possiblyFilteredInputStream(e, is, len, null);
405 
406 	}
407 
408 	private InputStream possiblyFilteredInputStream(final Entry e,
409 			final InputStream is, final long len, OperationType opType)
410 			throws IOException {
411 		if (getCleanFilterCommand() == null
412 				&& getEolStreamType(opType) == EolStreamType.DIRECT) {
413 			canonLen = len;
414 			return is;
415 		}
416 
417 		if (len <= MAXIMUM_FILE_SIZE_TO_READ_FULLY) {
418 			ByteBuffer rawbuf = IO.readWholeStream(is, (int) len);
419 			rawbuf = filterClean(rawbuf.array(), rawbuf.limit(), opType);
420 			canonLen = rawbuf.limit();
421 			return new ByteArrayInputStream(rawbuf.array(), 0, (int) canonLen);
422 		}
423 
424 		if (getCleanFilterCommand() == null && isBinary(e)) {
425 				canonLen = len;
426 				return is;
427 			}
428 
429 		final InputStream lenIs = filterClean(e.openInputStream(),
430 				opType);
431 		try {
432 			canonLen = computeLength(lenIs);
433 		} finally {
434 			safeClose(lenIs);
435 		}
436 		return filterClean(is, opType);
437 	}
438 
439 	private static void safeClose(InputStream in) {
440 		try {
441 			in.close();
442 		} catch (IOException err2) {
443 			// Suppress any error related to closing an input
444 			// stream. We don't care, we should not have any
445 			// outstanding data to flush or anything like that.
446 		}
447 	}
448 
449 	private static boolean isBinary(Entry entry) throws IOException {
450 		InputStream in = entry.openInputStream();
451 		try {
452 			return RawText.isBinary(in);
453 		} finally {
454 			safeClose(in);
455 		}
456 	}
457 
458 	private ByteBuffer filterClean(byte[] src, int n, OperationType opType)
459 			throws IOException {
460 		InputStream in = new ByteArrayInputStream(src);
461 		try {
462 			return IO.readWholeStream(filterClean(in, opType), n);
463 		} finally {
464 			safeClose(in);
465 		}
466 	}
467 
468 	private InputStream filterClean(InputStream in) throws IOException {
469 		return filterClean(in, null);
470 	}
471 
472 	private InputStream filterClean(InputStream in, OperationType opType)
473 			throws IOException {
474 		in = handleAutoCRLF(in, opType);
475 		String filterCommand = getCleanFilterCommand();
476 		if (filterCommand != null) {
477 			if (FilterCommandRegistry.isRegistered(filterCommand)) {
478 				LocalFile buffer = new TemporaryBuffer.LocalFile(null);
479 				FilterCommand command = FilterCommandRegistry
480 						.createFilterCommand(filterCommand, repository, in,
481 								buffer);
482 				while (command.run() != -1) {
483 					// loop as long as command.run() tells there is work to do
484 				}
485 				return buffer.openInputStreamWithAutoDestroy();
486 			}
487 			FS fs = repository.getFS();
488 			ProcessBuilder filterProcessBuilder = fs.runInShell(filterCommand,
489 					new String[0]);
490 			filterProcessBuilder.directory(repository.getWorkTree());
491 			filterProcessBuilder.environment().put(Constants.GIT_DIR_KEY,
492 					repository.getDirectory().getAbsolutePath());
493 			ExecutionResult result;
494 			try {
495 				result = fs.execute(filterProcessBuilder, in);
496 			} catch (IOException | InterruptedException e) {
497 				throw new IOException(new FilterFailedException(e,
498 						filterCommand, getEntryPathString()));
499 			}
500 			int rc = result.getRc();
501 			if (rc != 0) {
502 				throw new IOException(new FilterFailedException(rc,
503 						filterCommand, getEntryPathString(),
504 						result.getStdout().toByteArray(MAX_EXCEPTION_TEXT_SIZE),
505 						result.getStderr().toString(MAX_EXCEPTION_TEXT_SIZE)));
506 			}
507 			return result.getStdout().openInputStreamWithAutoDestroy();
508 		}
509 		return in;
510 	}
511 
512 	private InputStream handleAutoCRLF(InputStream in, OperationType opType)
513 			throws IOException {
514 		return EolStreamTypeUtil.wrapInputStream(in, getEolStreamType(opType));
515 	}
516 
517 	/**
518 	 * Returns the working tree options used by this iterator.
519 	 *
520 	 * @return working tree options
521 	 */
522 	public WorkingTreeOptions getOptions() {
523 		return state.options;
524 	}
525 
526 	/**
527 	 * Retrieves the {@link Repository} this {@link WorkingTreeIterator}
528 	 * operates on.
529 	 *
530 	 * @return the {@link Repository}
531 	 * @since 5.9
532 	 */
533 	public Repository getRepository() {
534 		return repository;
535 	}
536 
537 	/** {@inheritDoc} */
538 	@Override
539 	public int idOffset() {
540 		return contentIdOffset;
541 	}
542 
543 	/** {@inheritDoc} */
544 	@Override
545 	public void reset() {
546 		if (!first()) {
547 			ptr = 0;
548 			if (!eof())
549 				parseEntry();
550 		}
551 	}
552 
553 	/** {@inheritDoc} */
554 	@Override
555 	public boolean first() {
556 		return ptr == 0;
557 	}
558 
559 	/** {@inheritDoc} */
560 	@Override
561 	public boolean eof() {
562 		return ptr == entryCnt;
563 	}
564 
565 	/** {@inheritDoc} */
566 	@Override
567 	public void next(int delta) throws CorruptObjectException {
568 		ptr += delta;
569 		if (!eof()) {
570 			parseEntry();
571 		}
572 	}
573 
574 	/** {@inheritDoc} */
575 	@Override
576 	public void back(int delta) throws CorruptObjectException {
577 		ptr -= delta;
578 		parseEntry();
579 	}
580 
581 	private void parseEntry() {
582 		final Entry e = entries[ptr];
583 		mode = e.getMode().getBits();
584 
585 		final int nameLen = e.encodedNameLen;
586 		ensurePathCapacity(pathOffset + nameLen, pathOffset);
587 		System.arraycopy(e.encodedName, 0, path, pathOffset, nameLen);
588 		pathLen = pathOffset + nameLen;
589 		canonLen = -1;
590 		cleanFilterCommandHolder = null;
591 		eolStreamTypeHolder = null;
592 	}
593 
594 	/**
595 	 * Get the raw byte length of this entry.
596 	 *
597 	 * @return size of this file, in bytes.
598 	 */
599 	public long getEntryLength() {
600 		return current().getLength();
601 	}
602 
603 	/**
604 	 * Get the filtered input length of this entry
605 	 *
606 	 * @return size of the content, in bytes
607 	 * @throws java.io.IOException
608 	 */
609 	public long getEntryContentLength() throws IOException {
610 		if (canonLen == -1) {
611 			long rawLen = getEntryLength();
612 			if (rawLen == 0)
613 				canonLen = 0;
614 			InputStream is = current().openInputStream();
615 			try {
616 				// canonLen gets updated here
617 				possiblyFilteredInputStream(current(), is, current()
618 						.getLength());
619 			} finally {
620 				safeClose(is);
621 			}
622 		}
623 		return canonLen;
624 	}
625 
626 	/**
627 	 * Get the last modified time of this entry.
628 	 *
629 	 * @return last modified time of this file, in milliseconds since the epoch
630 	 *         (Jan 1, 1970 UTC).
631 	 * @deprecated use {@link #getEntryLastModifiedInstant()} instead
632 	 */
633 	@Deprecated
634 	public long getEntryLastModified() {
635 		return current().getLastModified();
636 	}
637 
638 	/**
639 	 * Get the last modified time of this entry.
640 	 *
641 	 * @return last modified time of this file
642 	 * @since 5.1.9
643 	 */
644 	public Instant getEntryLastModifiedInstant() {
645 		return current().getLastModifiedInstant();
646 	}
647 
648 	/**
649 	 * Obtain an input stream to read the file content.
650 	 * <p>
651 	 * Efficient implementations are not required. The caller will usually
652 	 * obtain the stream only once per entry, if at all.
653 	 * <p>
654 	 * The input stream should not use buffering if the implementation can avoid
655 	 * it. The caller will buffer as necessary to perform efficient block IO
656 	 * operations.
657 	 * <p>
658 	 * The caller will close the stream once complete.
659 	 *
660 	 * @return a stream to read from the file.
661 	 * @throws java.io.IOException
662 	 *             the file could not be opened for reading.
663 	 */
664 	public InputStream openEntryStream() throws IOException {
665 		InputStream rawis = current().openInputStream();
666 		if (getCleanFilterCommand() == null
667 				&& getEolStreamType() == EolStreamType.DIRECT) {
668 			return rawis;
669 		}
670 		return filterClean(rawis);
671 	}
672 
673 	/**
674 	 * Determine if the current entry path is ignored by an ignore rule.
675 	 *
676 	 * @return true if the entry was ignored by an ignore rule file.
677 	 * @throws java.io.IOException
678 	 *             a relevant ignore rule file exists but cannot be read.
679 	 */
680 	public boolean isEntryIgnored() throws IOException {
681 		return isEntryIgnored(pathLen);
682 	}
683 
684 	/**
685 	 * Determine if the entry path is ignored by an ignore rule.
686 	 *
687 	 * @param pLen
688 	 *            the length of the path in the path buffer.
689 	 * @return true if the entry is ignored by an ignore rule.
690 	 * @throws java.io.IOException
691 	 *             a relevant ignore rule file exists but cannot be read.
692 	 */
693 	protected boolean isEntryIgnored(int pLen) throws IOException {
694 		return isEntryIgnored(pLen, mode);
695 	}
696 
697 	/**
698 	 * Determine if the entry path is ignored by an ignore rule.
699 	 *
700 	 * @param pLen
701 	 *            the length of the path in the path buffer.
702 	 * @param fileMode
703 	 *            the original iterator file mode
704 	 * @return true if the entry is ignored by an ignore rule.
705 	 * @throws IOException
706 	 *             a relevant ignore rule file exists but cannot be read.
707 	 */
708 	private boolean isEntryIgnored(int pLen, int fileMode)
709 			throws IOException {
710 		// The ignore code wants path to start with a '/' if possible.
711 		// If we have the '/' in our path buffer because we are inside
712 		// a sub-directory include it in the range we convert to string.
713 		//
714 		final int pOff = 0 < pathOffset ? pathOffset - 1 : pathOffset;
715 		String pathRel = TreeWalk.pathOf(this.path, pOff, pLen);
716 		String parentRel = getParentPath(pathRel);
717 
718 		// CGit is processing .gitignore files by starting at the root of the
719 		// repository and then recursing into subdirectories. With this
720 		// approach, top-level ignored directories will be processed first which
721 		// allows to skip entire subtrees and further .gitignore-file processing
722 		// within these subtrees.
723 		//
724 		// We will follow the same approach by marking directories as "ignored"
725 		// here. This allows to have a simplified FastIgnore.checkIgnore()
726 		// implementation (both in terms of code and computational complexity):
727 		//
728 		// Without the "ignored" flag, we would have to apply the ignore-check
729 		// to a path and all of its parents always(!), to determine whether a
730 		// path is ignored directly or by one of its parent directories; with
731 		// the "ignored" flag, we know at this point that the parent directory
732 		// is definitely not ignored, thus the path can only become ignored if
733 		// there is a rule matching the path itself.
734 		if (isDirectoryIgnored(parentRel)) {
735 			return true;
736 		}
737 
738 		IgnoreNode rules = getIgnoreNode();
739 		final Boolean ignored = rules != null
740 				? rules.checkIgnored(pathRel, FileMode.TREE.equals(fileMode))
741 				: null;
742 		if (ignored != null) {
743 			return ignored.booleanValue();
744 		}
745 		return parent instanceof WorkingTreeIterator
746 				&& ((WorkingTreeIterator) parent).isEntryIgnored(pLen,
747 						fileMode);
748 	}
749 
750 	private IgnoreNode getIgnoreNode() throws IOException {
751 		if (ignoreNode instanceof PerDirectoryIgnoreNode)
752 			ignoreNode = ((PerDirectoryIgnoreNode) ignoreNode).load();
753 		return ignoreNode;
754 	}
755 
756 	/**
757 	 * Retrieves the {@link org.eclipse.jgit.attributes.AttributesNode} for the
758 	 * current entry.
759 	 *
760 	 * @return the {@link org.eclipse.jgit.attributes.AttributesNode} for the
761 	 *         current entry.
762 	 * @throws IOException
763 	 */
764 	public AttributesNode getEntryAttributesNode() throws IOException {
765 		if (attributesNode instanceof PerDirectoryAttributesNode)
766 			attributesNode = ((PerDirectoryAttributesNode) attributesNode)
767 					.load();
768 		return attributesNode;
769 	}
770 
771 	private static final Comparator<Entry> ENTRY_CMP = (Entry a,
772 			Entry b) -> Paths.compare(a.encodedName, 0, a.encodedNameLen,
773 					a.getMode().getBits(), b.encodedName, 0, b.encodedNameLen,
774 					b.getMode().getBits());
775 
776 	/**
777 	 * Constructor helper.
778 	 *
779 	 * @param list
780 	 *            files in the subtree of the work tree this iterator operates
781 	 *            on
782 	 */
783 	protected void init(Entry[] list) {
784 		// Filter out nulls, . and .. as these are not valid tree entries,
785 		// also cache the encoded forms of the path names for efficient use
786 		// later on during sorting and iteration.
787 		//
788 		entries = list;
789 		int i, o;
790 
791 		final CharsetEncoder nameEncoder = state.nameEncoder;
792 		for (i = 0, o = 0; i < entries.length; i++) {
793 			final Entry e = entries[i];
794 			if (e == null)
795 				continue;
796 			final String name = e.getName();
797 			if (".".equals(name) || "..".equals(name)) //$NON-NLS-1$ //$NON-NLS-2$
798 				continue;
799 			if (Constants.DOT_GIT.equals(name))
800 				continue;
801 			if (Constants.DOT_GIT_IGNORE.equals(name))
802 				ignoreNode = new PerDirectoryIgnoreNode(
803 						TreeWalk.pathOf(path, 0, pathOffset)
804 								+ Constants.DOT_GIT_IGNORE,
805 						e);
806 			if (Constants.DOT_GIT_ATTRIBUTES.equals(name))
807 				attributesNode = new PerDirectoryAttributesNode(e);
808 			if (i != o)
809 				entries[o] = e;
810 			e.encodeName(nameEncoder);
811 			o++;
812 		}
813 		entryCnt = o;
814 		Arrays.sort(entries, 0, entryCnt, ENTRY_CMP);
815 
816 		contentIdFromPtr = -1;
817 		ptr = 0;
818 		if (!eof())
819 			parseEntry();
820 		else if (pathLen == 0) // see bug 445363
821 			pathLen = pathOffset;
822 	}
823 
824 	/**
825 	 * Obtain the current entry from this iterator.
826 	 *
827 	 * @return the currently selected entry.
828 	 */
829 	protected Entry current() {
830 		return entries[ptr];
831 	}
832 
833 	/**
834 	 * The result of a metadata-comparison between the current entry and a
835 	 * {@link DirCacheEntry}
836 	 */
837 	public enum MetadataDiff {
838 		/**
839 		 * The entries are equal by metaData (mode, length,
840 		 * modification-timestamp) or the <code>assumeValid</code> attribute of
841 		 * the index entry is set
842 		 */
843 		EQUAL,
844 
845 		/**
846 		 * The entries are not equal by metaData (mode, length) or the
847 		 * <code>isUpdateNeeded</code> attribute of the index entry is set
848 		 */
849 		DIFFER_BY_METADATA,
850 
851 		/** index entry is smudged - can't use that entry for comparison */
852 		SMUDGED,
853 
854 		/**
855 		 * The entries are equal by metaData (mode, length) but differ by
856 		 * modification-timestamp.
857 		 */
858 		DIFFER_BY_TIMESTAMP
859 	}
860 
861 	/**
862 	 * Is the file mode of the current entry different than the given raw mode?
863 	 *
864 	 * @param rawMode
865 	 *            an int.
866 	 * @return true if different, false otherwise
867 	 */
868 	public boolean isModeDifferent(int rawMode) {
869 		// Determine difference in mode-bits of file and index-entry. In the
870 		// bitwise presentation of modeDiff we'll have a '1' when the two modes
871 		// differ at this position.
872 		int modeDiff = getEntryRawMode() ^ rawMode;
873 
874 		if (modeDiff == 0)
875 			return false;
876 
877 		// Do not rely on filemode differences in case of symbolic links
878 		if (getOptions().getSymLinks() == SymLinks.FALSE)
879 			if (FileMode.SYMLINK.equals(rawMode))
880 				return false;
881 
882 		// Ignore the executable file bits if WorkingTreeOptions tell me to
883 		// do so. Ignoring is done by setting the bits representing a
884 		// EXECUTABLE_FILE to '0' in modeDiff
885 		if (!state.options.isFileMode())
886 			modeDiff &= ~FileMode.EXECUTABLE_FILE.getBits();
887 		return modeDiff != 0;
888 	}
889 
890 	/**
891 	 * Compare the metadata (mode, length, modification-timestamp) of the
892 	 * current entry and a {@link org.eclipse.jgit.dircache.DirCacheEntry}
893 	 *
894 	 * @param entry
895 	 *            the {@link org.eclipse.jgit.dircache.DirCacheEntry} to compare
896 	 *            with
897 	 * @return a
898 	 *         {@link org.eclipse.jgit.treewalk.WorkingTreeIterator.MetadataDiff}
899 	 *         which tells whether and how the entries metadata differ
900 	 */
901 	public MetadataDiff compareMetadata(DirCacheEntry entry) {
902 		if (entry.isAssumeValid())
903 			return MetadataDiff.EQUAL;
904 
905 		if (entry.isUpdateNeeded())
906 			return MetadataDiff.DIFFER_BY_METADATA;
907 
908 		if (isModeDifferent(entry.getRawMode()))
909 			return MetadataDiff.DIFFER_BY_METADATA;
910 
911 		// Don't check for length or lastmodified on folders
912 		int type = mode & FileMode.TYPE_MASK;
913 		if (type == FileMode.TYPE_TREE || type == FileMode.TYPE_GITLINK)
914 			return MetadataDiff.EQUAL;
915 
916 		if (!entry.isSmudged() && entry.getLength() != (int) getEntryLength())
917 			return MetadataDiff.DIFFER_BY_METADATA;
918 
919 		// Cache and file timestamps may differ in resolution. Therefore don't
920 		// compare instants directly but use a comparator that compares only
921 		// up to the lower apparent resolution of either timestamp.
922 		//
923 		// If core.checkstat is set to "minimal", compare only the seconds part.
924 		Instant cacheLastModified = entry.getLastModifiedInstant();
925 		Instant fileLastModified = getEntryLastModifiedInstant();
926 		if (timestampComparator.compare(cacheLastModified, fileLastModified,
927 				getOptions().getCheckStat() == CheckStat.MINIMAL) != 0) {
928 			return MetadataDiff.DIFFER_BY_TIMESTAMP;
929 		}
930 
931 		if (entry.isSmudged()) {
932 			return MetadataDiff.SMUDGED;
933 		}
934 		// The file is clean when when comparing timestamps
935 		return MetadataDiff.EQUAL;
936 	}
937 
938 	/**
939 	 * Checks whether this entry differs from a given entry from the
940 	 * {@link org.eclipse.jgit.dircache.DirCache}.
941 	 *
942 	 * File status information is used and if status is same we consider the
943 	 * file identical to the state in the working directory. Native git uses
944 	 * more stat fields than we have accessible in Java.
945 	 *
946 	 * @param entry
947 	 *            the entry from the dircache we want to compare against
948 	 * @param forceContentCheck
949 	 *            True if the actual file content should be checked if
950 	 *            modification time differs.
951 	 * @param reader
952 	 *            access to repository objects if necessary. Should not be null.
953 	 * @return true if content is most likely different.
954 	 * @throws java.io.IOException
955 	 * @since 3.3
956 	 */
957 	public boolean isModified(DirCacheEntry entry, boolean forceContentCheck,
958 			ObjectReader reader) throws IOException {
959 		if (entry == null)
960 			return !FileMode.MISSING.equals(getEntryFileMode());
961 		MetadataDiff diff = compareMetadata(entry);
962 		switch (diff) {
963 		case DIFFER_BY_TIMESTAMP:
964 			if (forceContentCheck) {
965 				// But we are told to look at content even though timestamps
966 				// tell us about modification
967 				return contentCheck(entry, reader);
968 			}
969 			// We are told to assume a modification if timestamps differs
970 			return true;
971 		case SMUDGED:
972 			// The file is clean by timestamps but the entry was smudged.
973 			// Lets do a content check
974 			return contentCheck(entry, reader);
975 		case EQUAL:
976 			if (mode == FileMode.SYMLINK.getBits()) {
977 				return contentCheck(entry, reader);
978 			}
979 			return false;
980 		case DIFFER_BY_METADATA:
981 			if (mode == FileMode.TREE.getBits()
982 					&& entry.getFileMode().equals(FileMode.GITLINK)) {
983 				byte[] idBuffer = idBuffer();
984 				int idOffset = idOffset();
985 				if (entry.getObjectId().compareTo(idBuffer, idOffset) == 0) {
986 					return true;
987 				} else if (ObjectId.zeroId().compareTo(idBuffer,
988 						idOffset) == 0) {
989 					Path p = repository.getWorkTree().toPath()
990 							.resolve(entry.getPathString());
991 					return FileUtils.hasFiles(p);
992 				}
993 				return false;
994 			} else if (mode == FileMode.SYMLINK.getBits())
995 				return contentCheck(entry, reader);
996 			return true;
997 		default:
998 			throw new IllegalStateException(MessageFormat.format(
999 					JGitText.get().unexpectedCompareResult, diff.name()));
1000 		}
1001 	}
1002 
1003 	/**
1004 	 * Get the file mode to use for the current entry when it is to be updated
1005 	 * in the index.
1006 	 *
1007 	 * @param indexIter
1008 	 *            {@link org.eclipse.jgit.dircache.DirCacheIterator} positioned
1009 	 *            at the same entry as this iterator or null if no
1010 	 *            {@link org.eclipse.jgit.dircache.DirCacheIterator} is
1011 	 *            available at this iterator's current entry
1012 	 * @return index file mode
1013 	 */
1014 	public FileMode getIndexFileMode(DirCacheIterator indexIter) {
1015 		final FileMode wtMode = getEntryFileMode();
1016 		if (indexIter == null) {
1017 			return wtMode;
1018 		}
1019 		final FileMode iMode = indexIter.getEntryFileMode();
1020 		if (getOptions().isFileMode() && iMode != FileMode.GITLINK && iMode != FileMode.TREE) {
1021 			return wtMode;
1022 		}
1023 		if (!getOptions().isFileMode()) {
1024 			if (FileMode.REGULAR_FILE == wtMode
1025 					&& FileMode.EXECUTABLE_FILE == iMode) {
1026 				return iMode;
1027 			}
1028 			if (FileMode.EXECUTABLE_FILE == wtMode
1029 					&& FileMode.REGULAR_FILE == iMode) {
1030 				return iMode;
1031 			}
1032 		}
1033 		if (FileMode.GITLINK == iMode
1034 				&& FileMode.TREE == wtMode && !getOptions().isDirNoGitLinks()) {
1035 			return iMode;
1036 		}
1037 		if (FileMode.TREE == iMode
1038 				&& FileMode.GITLINK == wtMode) {
1039 			return iMode;
1040 		}
1041 		return wtMode;
1042 	}
1043 
1044 	/**
1045 	 * Compares the entries content with the content in the filesystem.
1046 	 * Unsmudges the entry when it is detected that it is clean.
1047 	 *
1048 	 * @param entry
1049 	 *            the entry to be checked
1050 	 * @param reader
1051 	 *            acccess to repository data if necessary
1052 	 * @return <code>true</code> if the content doesn't match,
1053 	 *         <code>false</code> if it matches
1054 	 * @throws IOException
1055 	 */
1056 	private boolean contentCheck(DirCacheEntry entry, ObjectReader reader)
1057 			throws IOException {
1058 		if (getEntryObjectId().equals(entry.getObjectId())) {
1059 			// Content has not changed
1060 
1061 			// We know the entry can't be racily clean because it's still clean.
1062 			// Therefore we unsmudge the entry!
1063 			// If by any chance we now unsmudge although we are still in the
1064 			// same time-slot as the last modification to the index file the
1065 			// next index write operation will smudge again.
1066 			// Caution: we are unsmudging just by setting the length of the
1067 			// in-memory entry object. It's the callers task to detect that we
1068 			// have modified the entry and to persist the modified index.
1069 			entry.setLength((int) getEntryLength());
1070 
1071 			return false;
1072 		}
1073 		if (mode == FileMode.SYMLINK.getBits()) {
1074 			return !new File(readSymlinkTarget(current())).equals(
1075 					new File(readContentAsNormalizedString(entry, reader)));
1076 		}
1077 		// Content differs: that's a real change
1078 		return true;
1079 	}
1080 
1081 	private static String readContentAsNormalizedString(DirCacheEntry entry,
1082 			ObjectReader reader) throws MissingObjectException, IOException {
1083 		ObjectLoader open = reader.open(entry.getObjectId());
1084 		byte[] cachedBytes = open.getCachedBytes();
1085 		return FS.detect().normalize(RawParseUtils.decode(cachedBytes));
1086 	}
1087 
1088 	/**
1089 	 * Reads the target of a symlink as a string. This default implementation
1090 	 * fully reads the entry's input stream and converts it to a normalized
1091 	 * string. Subclasses may override to provide more specialized
1092 	 * implementations.
1093 	 *
1094 	 * @param entry
1095 	 *            to read
1096 	 * @return the entry's content as a normalized string
1097 	 * @throws java.io.IOException
1098 	 *             if the entry cannot be read or does not denote a symlink
1099 	 * @since 4.6
1100 	 */
1101 	protected String readSymlinkTarget(Entry entry) throws IOException {
1102 		if (!entry.getMode().equals(FileMode.SYMLINK)) {
1103 			throw new java.nio.file.NotLinkException(entry.getName());
1104 		}
1105 		long length = entry.getLength();
1106 		byte[] content = new byte[(int) length];
1107 		try (InputStream is = entry.openInputStream()) {
1108 			int bytesRead = IO.readFully(is, content, 0);
1109 			return FS.detect()
1110 					.normalize(RawParseUtils.decode(content, 0, bytesRead));
1111 		}
1112 	}
1113 
1114 	private static long computeLength(InputStream in) throws IOException {
1115 		// Since we only care about the length, use skip. The stream
1116 		// may be able to more efficiently wade through its data.
1117 		//
1118 		long length = 0;
1119 		for (;;) {
1120 			long n = in.skip(1 << 20);
1121 			if (n <= 0)
1122 				break;
1123 			length += n;
1124 		}
1125 		return length;
1126 	}
1127 
1128 	private byte[] computeHash(InputStream in, long length) throws IOException {
1129 		SHA1 contentDigest = SHA1.newInstance();
1130 		final byte[] contentReadBuffer = state.contentReadBuffer;
1131 
1132 		contentDigest.update(hblob);
1133 		contentDigest.update((byte) ' ');
1134 
1135 		long sz = length;
1136 		if (sz == 0) {
1137 			contentDigest.update((byte) '0');
1138 		} else {
1139 			final int bufn = contentReadBuffer.length;
1140 			int p = bufn;
1141 			do {
1142 				contentReadBuffer[--p] = digits[(int) (sz % 10)];
1143 				sz /= 10;
1144 			} while (sz > 0);
1145 			contentDigest.update(contentReadBuffer, p, bufn - p);
1146 		}
1147 		contentDigest.update((byte) 0);
1148 
1149 		for (;;) {
1150 			final int r = in.read(contentReadBuffer);
1151 			if (r <= 0)
1152 				break;
1153 			contentDigest.update(contentReadBuffer, 0, r);
1154 			sz += r;
1155 		}
1156 		if (sz != length)
1157 			return zeroid;
1158 		return contentDigest.digest();
1159 	}
1160 
1161 	/**
1162 	 * A single entry within a working directory tree.
1163 	 *
1164 	 * @since 5.0
1165 	 */
1166 	public abstract static class Entry {
1167 		byte[] encodedName;
1168 
1169 		int encodedNameLen;
1170 
1171 		void encodeName(CharsetEncoder enc) {
1172 			final ByteBuffer b;
1173 			try {
1174 				b = enc.encode(CharBuffer.wrap(getName()));
1175 			} catch (CharacterCodingException e) {
1176 				// This should so never happen.
1177 				throw new RuntimeException(MessageFormat.format(
1178 						JGitText.get().unencodeableFile, getName()), e);
1179 			}
1180 
1181 			encodedNameLen = b.limit();
1182 			if (b.hasArray() && b.arrayOffset() == 0)
1183 				encodedName = b.array();
1184 			else
1185 				b.get(encodedName = new byte[encodedNameLen]);
1186 		}
1187 
1188 		@Override
1189 		public String toString() {
1190 			return getMode().toString() + " " + getName(); //$NON-NLS-1$
1191 		}
1192 
1193 		/**
1194 		 * Get the type of this entry.
1195 		 * <p>
1196 		 * <b>Note: Efficient implementation required.</b>
1197 		 * <p>
1198 		 * The implementation of this method must be efficient. If a subclass
1199 		 * needs to compute the value they should cache the reference within an
1200 		 * instance member instead.
1201 		 *
1202 		 * @return a file mode constant from {@link FileMode}.
1203 		 */
1204 		public abstract FileMode getMode();
1205 
1206 		/**
1207 		 * Get the byte length of this entry.
1208 		 * <p>
1209 		 * <b>Note: Efficient implementation required.</b>
1210 		 * <p>
1211 		 * The implementation of this method must be efficient. If a subclass
1212 		 * needs to compute the value they should cache the reference within an
1213 		 * instance member instead.
1214 		 *
1215 		 * @return size of this file, in bytes.
1216 		 */
1217 		public abstract long getLength();
1218 
1219 		/**
1220 		 * Get the last modified time of this entry.
1221 		 * <p>
1222 		 * <b>Note: Efficient implementation required.</b>
1223 		 * <p>
1224 		 * The implementation of this method must be efficient. If a subclass
1225 		 * needs to compute the value they should cache the reference within an
1226 		 * instance member instead.
1227 		 *
1228 		 * @return time since the epoch (in ms) of the last change.
1229 		 * @deprecated use {@link #getLastModifiedInstant()} instead
1230 		 */
1231 		@Deprecated
1232 		public abstract long getLastModified();
1233 
1234 		/**
1235 		 * Get the last modified time of this entry.
1236 		 * <p>
1237 		 * <b>Note: Efficient implementation required.</b>
1238 		 * <p>
1239 		 * The implementation of this method must be efficient. If a subclass
1240 		 * needs to compute the value they should cache the reference within an
1241 		 * instance member instead.
1242 		 *
1243 		 * @return time of the last change.
1244 		 * @since 5.1.9
1245 		 */
1246 		public abstract Instant getLastModifiedInstant();
1247 
1248 		/**
1249 		 * Get the name of this entry within its directory.
1250 		 * <p>
1251 		 * Efficient implementations are not required. The caller will obtain
1252 		 * the name only once and cache it once obtained.
1253 		 *
1254 		 * @return name of the entry.
1255 		 */
1256 		public abstract String getName();
1257 
1258 		/**
1259 		 * Obtain an input stream to read the file content.
1260 		 * <p>
1261 		 * Efficient implementations are not required. The caller will usually
1262 		 * obtain the stream only once per entry, if at all.
1263 		 * <p>
1264 		 * The input stream should not use buffering if the implementation can
1265 		 * avoid it. The caller will buffer as necessary to perform efficient
1266 		 * block IO operations.
1267 		 * <p>
1268 		 * The caller will close the stream once complete.
1269 		 *
1270 		 * @return a stream to read from the file.
1271 		 * @throws IOException
1272 		 *             the file could not be opened for reading.
1273 		 */
1274 		public abstract InputStream openInputStream() throws IOException;
1275 	}
1276 
1277 	/** Magic type indicating we know rules exist, but they aren't loaded. */
1278 	private static class PerDirectoryIgnoreNode extends IgnoreNode {
1279 		protected final Entry entry;
1280 
1281 		private final String name;
1282 
1283 		PerDirectoryIgnoreNode(String name, Entry entry) {
1284 			super(Collections.<FastIgnoreRule> emptyList());
1285 			this.name = name;
1286 			this.entry = entry;
1287 		}
1288 
1289 		IgnoreNode load() throws IOException {
1290 			IgnoreNode r = new IgnoreNode();
1291 			try (InputStream in = entry.openInputStream()) {
1292 				r.parse(name, in);
1293 			}
1294 			return r.getRules().isEmpty() ? null : r;
1295 		}
1296 	}
1297 
1298 	/** Magic type indicating there may be rules for the top level. */
1299 	private static class RootIgnoreNode extends PerDirectoryIgnoreNode {
1300 		final Repository repository;
1301 
1302 		RootIgnoreNode(Entry entry, Repository repository) {
1303 			super(entry != null ? entry.getName() : null, entry);
1304 			this.repository = repository;
1305 		}
1306 
1307 		@Override
1308 		IgnoreNode load() throws IOException {
1309 			IgnoreNode r;
1310 			if (entry != null) {
1311 				r = super.load();
1312 				if (r == null)
1313 					r = new IgnoreNode();
1314 			} else {
1315 				r = new IgnoreNode();
1316 			}
1317 
1318 			FS fs = repository.getFS();
1319 			Path path = repository.getConfig().getPath(
1320 					ConfigConstants.CONFIG_CORE_SECTION, null,
1321 					ConfigConstants.CONFIG_KEY_EXCLUDESFILE, fs, null, null);
1322 			if (path != null) {
1323 				loadRulesFromFile(r, path.toFile());
1324 			}
1325 
1326 			File exclude = fs.resolve(repository.getDirectory(),
1327 					Constants.INFO_EXCLUDE);
1328 			loadRulesFromFile(r, exclude);
1329 
1330 			return r.getRules().isEmpty() ? null : r;
1331 		}
1332 
1333 		private static void loadRulesFromFile(IgnoreNode r, File exclude)
1334 				throws FileNotFoundException, IOException {
1335 			if (FS.DETECTED.exists(exclude)) {
1336 				try (FileInputStream in = new FileInputStream(exclude)) {
1337 					r.parse(exclude.getAbsolutePath(), in);
1338 				}
1339 			}
1340 		}
1341 	}
1342 
1343 	/** Magic type indicating we know rules exist, but they aren't loaded. */
1344 	private static class PerDirectoryAttributesNode extends AttributesNode {
1345 		final Entry entry;
1346 
1347 		PerDirectoryAttributesNode(Entry entry) {
1348 			super(Collections.<AttributesRule> emptyList());
1349 			this.entry = entry;
1350 		}
1351 
1352 		AttributesNode load() throws IOException {
1353 			AttributesNode r = new AttributesNode();
1354 			try (InputStream in = entry.openInputStream()) {
1355 				r.parse(in);
1356 			}
1357 			return r.getRules().isEmpty() ? null : r;
1358 		}
1359 	}
1360 
1361 
1362 	private static final class IteratorState {
1363 		/** Options used to process the working tree. */
1364 		final WorkingTreeOptions options;
1365 
1366 		/** File name character encoder. */
1367 		final CharsetEncoder nameEncoder;
1368 
1369 		/** Buffer used to perform {@link #contentId} computations. */
1370 		byte[] contentReadBuffer;
1371 
1372 		/** TreeWalk with a (supposedly) matching DirCacheIterator. */
1373 		TreeWalk walk;
1374 
1375 		/** Position of the matching {@link DirCacheIterator}. */
1376 		int dirCacheTree = -1;
1377 
1378 		/** Whether the iterator shall walk ignored directories. */
1379 		boolean walkIgnored = false;
1380 
1381 		final Map<String, Boolean> directoryToIgnored = new HashMap<>();
1382 
1383 		IteratorState(WorkingTreeOptions options) {
1384 			this.options = options;
1385 			this.nameEncoder = UTF_8.newEncoder();
1386 		}
1387 
1388 		void initializeReadBuffer() {
1389 			if (contentReadBuffer == null) {
1390 				contentReadBuffer = new byte[BUFFER_SIZE];
1391 			}
1392 		}
1393 	}
1394 
1395 	/**
1396 	 * Get the clean filter command for the current entry.
1397 	 *
1398 	 * @return the clean filter command for the current entry or
1399 	 *         <code>null</code> if no such command is defined
1400 	 * @throws java.io.IOException
1401 	 * @since 4.2
1402 	 */
1403 	public String getCleanFilterCommand() throws IOException {
1404 		if (cleanFilterCommandHolder == null) {
1405 			String cmd = null;
1406 			if (state.walk != null) {
1407 				cmd = state.walk
1408 						.getFilterCommand(Constants.ATTR_FILTER_TYPE_CLEAN);
1409 			}
1410 			cleanFilterCommandHolder = new Holder<>(cmd);
1411 		}
1412 		return cleanFilterCommandHolder.get();
1413 	}
1414 
1415 	/**
1416 	 * Get the eol stream type for the current entry.
1417 	 *
1418 	 * @return the eol stream type for the current entry or <code>null</code> if
1419 	 *         it cannot be determined. When state or state.walk is null or the
1420 	 *         {@link org.eclipse.jgit.treewalk.TreeWalk} is not based on a
1421 	 *         {@link org.eclipse.jgit.lib.Repository} then null is returned.
1422 	 * @throws java.io.IOException
1423 	 * @since 4.3
1424 	 */
1425 	public EolStreamType getEolStreamType() throws IOException {
1426 		return getEolStreamType(null);
1427 	}
1428 
1429 	/**
1430 	 * @param opType
1431 	 *            The operationtype (checkin/checkout) which should be used
1432 	 * @return the eol stream type for the current entry or <code>null</code> if
1433 	 *         it cannot be determined. When state or state.walk is null or the
1434 	 *         {@link TreeWalk} is not based on a {@link Repository} then null
1435 	 *         is returned.
1436 	 * @throws IOException
1437 	 */
1438 	private EolStreamType getEolStreamType(OperationType opType)
1439 			throws IOException {
1440 		if (eolStreamTypeHolder == null) {
1441 			EolStreamType type = null;
1442 			if (state.walk != null) {
1443 				type = state.walk.getEolStreamType(opType);
1444 				OperationType operationType = opType != null ? opType
1445 						: state.walk.getOperationType();
1446 				if (OperationType.CHECKIN_OP.equals(operationType)
1447 						&& EolStreamType.AUTO_LF.equals(type)
1448 						&& hasCrLfInIndex(getDirCacheIterator())) {
1449 					// If text=auto (or core.autocrlf=true) and the file has
1450 					// already been committed with CR/LF, then don't convert.
1451 					type = EolStreamType.DIRECT;
1452 				}
1453 			} else {
1454 				switch (getOptions().getAutoCRLF()) {
1455 				case FALSE:
1456 					type = EolStreamType.DIRECT;
1457 					break;
1458 				case TRUE:
1459 				case INPUT:
1460 					type = EolStreamType.AUTO_LF;
1461 					break;
1462 				}
1463 			}
1464 			eolStreamTypeHolder = new Holder<>(type);
1465 		}
1466 		return eolStreamTypeHolder.get();
1467 	}
1468 
1469 	/**
1470 	 * Determines whether the file was committed un-normalized. If the iterator
1471 	 * points to a conflict entry, checks the "ours" version.
1472 	 *
1473 	 * @param dirCache
1474 	 *            iterator pointing to the current entry for the file in the
1475 	 *            index
1476 	 * @return {@code true} if the file in the index is not binary and has CR/LF
1477 	 *         line endings, {@code false} otherwise
1478 	 */
1479 	private boolean hasCrLfInIndex(DirCacheIterator dirCache) {
1480 		if (dirCache == null) {
1481 			return false;
1482 		}
1483 		// Read blob from index and check for CR/LF-delimited text.
1484 		DirCacheEntry entry = dirCache.getDirCacheEntry();
1485 		if ((entry.getRawMode() & FileMode.TYPE_MASK) == FileMode.TYPE_FILE) {
1486 			ObjectId blobId = entry.getObjectId();
1487 			if (entry.getStage() > 0
1488 					&& entry.getStage() != DirCacheEntry.STAGE_2) {
1489 				blobId = null;
1490 				// Merge conflict: check ours (stage 2)
1491 				byte[] name = entry.getRawPath();
1492 				int i = 0;
1493 				while (!dirCache.eof()) {
1494 					dirCache.next(1);
1495 					i++;
1496 					entry = dirCache.getDirCacheEntry();
1497 					if (entry == null
1498 							|| !Arrays.equals(name, entry.getRawPath())) {
1499 						break;
1500 					}
1501 					if (entry.getStage() == DirCacheEntry.STAGE_2) {
1502 						if ((entry.getRawMode()
1503 								& FileMode.TYPE_MASK) == FileMode.TYPE_FILE) {
1504 							blobId = entry.getObjectId();
1505 						}
1506 						break;
1507 					}
1508 				}
1509 				dirCache.back(i);
1510 			}
1511 			if (blobId != null) {
1512 				try (ObjectReader reader = repository.newObjectReader()) {
1513 					ObjectLoader loader = reader.open(blobId,
1514 							Constants.OBJ_BLOB);
1515 					try {
1516 						return RawText.isCrLfText(loader.getCachedBytes());
1517 					} catch (LargeObjectException e) {
1518 						try (InputStream in = loader.openStream()) {
1519 							return RawText.isCrLfText(in);
1520 						}
1521 					}
1522 				} catch (IOException e) {
1523 					// Ignore and return false below
1524 				}
1525 			}
1526 		}
1527 		return false;
1528 	}
1529 
1530 	private boolean isDirectoryIgnored(String pathRel) throws IOException {
1531 		final int pOff = 0 < pathOffset ? pathOffset - 1 : pathOffset;
1532 		final String base = TreeWalk.pathOf(this.path, 0, pOff);
1533 		final String pathAbs = concatPath(base, pathRel);
1534 		return isDirectoryIgnored(pathRel, pathAbs);
1535 	}
1536 
1537 	private boolean isDirectoryIgnored(String pathRel, String pathAbs)
1538 			throws IOException {
1539 		assert pathRel.length() == 0 || (pathRel.charAt(0) != '/'
1540 				&& pathRel.charAt(pathRel.length() - 1) != '/');
1541 		assert pathAbs.length() == 0 || (pathAbs.charAt(0) != '/'
1542 				&& pathAbs.charAt(pathAbs.length() - 1) != '/');
1543 		assert pathAbs.endsWith(pathRel);
1544 
1545 		Boolean ignored = state.directoryToIgnored.get(pathAbs);
1546 		if (ignored != null) {
1547 			return ignored.booleanValue();
1548 		}
1549 
1550 		final String parentRel = getParentPath(pathRel);
1551 		if (parentRel != null && isDirectoryIgnored(parentRel)) {
1552 			state.directoryToIgnored.put(pathAbs, Boolean.TRUE);
1553 			return true;
1554 		}
1555 
1556 		final IgnoreNode node = getIgnoreNode();
1557 		for (String p = pathRel; node != null
1558 				&& !"".equals(p); p = getParentPath(p)) { //$NON-NLS-1$
1559 			ignored = node.checkIgnored(p, true);
1560 			if (ignored != null) {
1561 				state.directoryToIgnored.put(pathAbs, ignored);
1562 				return ignored.booleanValue();
1563 			}
1564 		}
1565 
1566 		if (!(this.parent instanceof WorkingTreeIterator)) {
1567 			state.directoryToIgnored.put(pathAbs, Boolean.FALSE);
1568 			return false;
1569 		}
1570 
1571 		final WorkingTreeIterator wtParent = (WorkingTreeIterator) this.parent;
1572 		final String parentRelPath = concatPath(
1573 				TreeWalk.pathOf(this.path, wtParent.pathOffset, pathOffset - 1),
1574 				pathRel);
1575 		assert concatPath(TreeWalk.pathOf(wtParent.path, 0,
1576 				Math.max(0, wtParent.pathOffset - 1)), parentRelPath)
1577 						.equals(pathAbs);
1578 		return wtParent.isDirectoryIgnored(parentRelPath, pathAbs);
1579 	}
1580 
1581 	private static String getParentPath(String path) {
1582 		final int slashIndex = path.lastIndexOf('/', path.length() - 2);
1583 		if (slashIndex > 0) {
1584 			return path.substring(path.charAt(0) == '/' ? 1 : 0, slashIndex);
1585 		}
1586 		return path.length() > 0 ? "" : null; //$NON-NLS-1$
1587 	}
1588 
1589 	private static String concatPath(String p1, String p2) {
1590 		return p1 + (p1.length() > 0 && p2.length() > 0 ? "/" : "") + p2; //$NON-NLS-1$ //$NON-NLS-2$
1591 	}
1592 }