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- /*
- * Copyright (C) 2008, Shawn O. Pearce <spearce@spearce.org>
- * and other copyright owners as documented in the project's IP log.
- *
- * This program and the accompanying materials are made available
- * under the terms of the Eclipse Distribution License v1.0 which
- * accompanies this distribution, is reproduced below, and is
- * available at http://www.eclipse.org/org/documents/edl-v10.php
- *
- * All rights reserved.
- *
- * Redistribution and use in source and binary forms, with or
- * without modification, are permitted provided that the following
- * conditions are met:
- *
- * - Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- *
- * - Redistributions in binary form must reproduce the above
- * copyright notice, this list of conditions and the following
- * disclaimer in the documentation and/or other materials provided
- * with the distribution.
- *
- * - Neither the name of the Eclipse Foundation, Inc. nor the
- * names of its contributors may be used to endorse or promote
- * products derived from this software without specific prior
- * written permission.
- *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND
- * CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
- * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
- * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
- * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
- * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
- * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
- * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
- * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
- * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
- * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
- * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
- * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
- */
-
- package org.eclipse.jgit.treewalk;
-
- import java.io.IOException;
- import java.io.InputStream;
- import java.nio.ByteBuffer;
- import java.nio.CharBuffer;
- import java.nio.charset.CharacterCodingException;
- import java.nio.charset.CharsetEncoder;
- import java.security.MessageDigest;
- import java.util.Arrays;
- import java.util.Comparator;
-
- import org.eclipse.jgit.errors.CorruptObjectException;
- import org.eclipse.jgit.lib.Constants;
- import org.eclipse.jgit.lib.FileMode;
-
- /**
- * Walks a working directory tree as part of a {@link TreeWalk}.
- * <p>
- * Most applications will want to use the standard implementation of this
- * iterator, {@link FileTreeIterator}, as that does all IO through the standard
- * <code>java.io</code> package. Plugins for a Java based IDE may however wish
- * to create their own implementations of this class to allow traversal of the
- * IDE's project space, as well as benefit from any caching the IDE may have.
- *
- * @see FileTreeIterator
- */
- public abstract class WorkingTreeIterator extends AbstractTreeIterator {
- /** An empty entry array, suitable for {@link #init(Entry[])}. */
- protected static final Entry[] EOF = {};
-
- /** Size we perform file IO in if we have to read and hash a file. */
- private static final int BUFFER_SIZE = 2048;
-
- /** The {@link #idBuffer()} for the current entry. */
- private byte[] contentId;
-
- /** Index within {@link #entries} that {@link #contentId} came from. */
- private int contentIdFromPtr;
-
- /** Buffer used to perform {@link #contentId} computations. */
- private byte[] contentReadBuffer;
-
- /** Digest computer for {@link #contentId} computations. */
- private MessageDigest contentDigest;
-
- /** File name character encoder. */
- private final CharsetEncoder nameEncoder;
-
- /** List of entries obtained from the subclass. */
- private Entry[] entries;
-
- /** Total number of entries in {@link #entries} that are valid. */
- private int entryCnt;
-
- /** Current position within {@link #entries}. */
- private int ptr;
-
- /** Create a new iterator with no parent. */
- protected WorkingTreeIterator() {
- super();
- nameEncoder = Constants.CHARSET.newEncoder();
- }
-
- /**
- * Create a new iterator with no parent and a prefix.
- * <p>
- * The prefix path supplied is inserted in front of all paths generated by
- * this iterator. It is intended to be used when an iterator is being
- * created for a subsection of an overall repository and needs to be
- * combined with other iterators that are created to run over the entire
- * repository namespace.
- *
- * @param prefix
- * position of this iterator in the repository tree. The value
- * may be null or the empty string to indicate the prefix is the
- * root of the repository. A trailing slash ('/') is
- * automatically appended if the prefix does not end in '/'.
- */
- protected WorkingTreeIterator(final String prefix) {
- super(prefix);
- nameEncoder = Constants.CHARSET.newEncoder();
- }
-
- /**
- * Create an iterator for a subtree of an existing iterator.
- *
- * @param p
- * parent tree iterator.
- */
- protected WorkingTreeIterator(final WorkingTreeIterator p) {
- super(p);
- nameEncoder = p.nameEncoder;
- }
-
- @Override
- public byte[] idBuffer() {
- if (contentIdFromPtr == ptr)
- return contentId;
- switch (mode & FileMode.TYPE_MASK) {
- case FileMode.TYPE_FILE:
- contentIdFromPtr = ptr;
- return contentId = idBufferBlob(entries[ptr]);
- case FileMode.TYPE_SYMLINK:
- // Java does not support symbolic links, so we should not
- // have reached this particular part of the walk code.
- //
- return zeroid;
- case FileMode.TYPE_GITLINK:
- // TODO: Support obtaining current HEAD SHA-1 from nested repository
- //
- return zeroid;
- }
- return zeroid;
- }
-
- private void initializeDigest() {
- if (contentDigest != null)
- return;
-
- if (parent == null) {
- contentReadBuffer = new byte[BUFFER_SIZE];
- contentDigest = Constants.newMessageDigest();
- } else {
- final WorkingTreeIterator p = (WorkingTreeIterator) parent;
- p.initializeDigest();
- contentReadBuffer = p.contentReadBuffer;
- contentDigest = p.contentDigest;
- }
- }
-
- private static final byte[] digits = { '0', '1', '2', '3', '4', '5', '6',
- '7', '8', '9' };
-
- private static final byte[] hblob = Constants
- .encodedTypeString(Constants.OBJ_BLOB);
-
- private byte[] idBufferBlob(final Entry e) {
- try {
- final InputStream is = e.openInputStream();
- if (is == null)
- return zeroid;
- try {
- initializeDigest();
-
- contentDigest.reset();
- contentDigest.update(hblob);
- contentDigest.update((byte) ' ');
-
- final long blobLength = e.getLength();
- long sz = blobLength;
- if (sz == 0) {
- contentDigest.update((byte) '0');
- } else {
- final int bufn = contentReadBuffer.length;
- int p = bufn;
- do {
- contentReadBuffer[--p] = digits[(int) (sz % 10)];
- sz /= 10;
- } while (sz > 0);
- contentDigest.update(contentReadBuffer, p, bufn - p);
- }
- contentDigest.update((byte) 0);
-
- for (;;) {
- final int r = is.read(contentReadBuffer);
- if (r <= 0)
- break;
- contentDigest.update(contentReadBuffer, 0, r);
- sz += r;
- }
- if (sz != blobLength)
- return zeroid;
- return contentDigest.digest();
- } finally {
- try {
- is.close();
- } catch (IOException err2) {
- // Suppress any error related to closing an input
- // stream. We don't care, we should not have any
- // outstanding data to flush or anything like that.
- }
- }
- } catch (IOException err) {
- // Can't read the file? Don't report the failure either.
- //
- return zeroid;
- }
- }
-
- @Override
- public int idOffset() {
- return 0;
- }
-
- @Override
- public boolean first() {
- return ptr == 0;
- }
-
- @Override
- public boolean eof() {
- return ptr == entryCnt;
- }
-
- @Override
- public void next(final int delta) throws CorruptObjectException {
- ptr += delta;
- if (!eof())
- parseEntry();
- }
-
- @Override
- public void back(final int delta) throws CorruptObjectException {
- ptr -= delta;
- parseEntry();
- }
-
- private void parseEntry() {
- final Entry e = entries[ptr];
- mode = e.getMode().getBits();
-
- final int nameLen = e.encodedNameLen;
- ensurePathCapacity(pathOffset + nameLen, pathOffset);
- System.arraycopy(e.encodedName, 0, path, pathOffset, nameLen);
- pathLen = pathOffset + nameLen;
- }
-
- /**
- * Get the byte length of this entry.
- *
- * @return size of this file, in bytes.
- */
- public long getEntryLength() {
- return current().getLength();
- }
-
- /**
- * Get the last modified time of this entry.
- *
- * @return last modified time of this file, in milliseconds since the epoch
- * (Jan 1, 1970 UTC).
- */
- public long getEntryLastModified() {
- return current().getLastModified();
- }
-
- private static final Comparator<Entry> ENTRY_CMP = new Comparator<Entry>() {
- public int compare(final Entry o1, final Entry o2) {
- final byte[] a = o1.encodedName;
- final byte[] b = o2.encodedName;
- final int aLen = o1.encodedNameLen;
- final int bLen = o2.encodedNameLen;
- int cPos;
-
- for (cPos = 0; cPos < aLen && cPos < bLen; cPos++) {
- final int cmp = (a[cPos] & 0xff) - (b[cPos] & 0xff);
- if (cmp != 0)
- return cmp;
- }
-
- if (cPos < aLen)
- return (a[cPos] & 0xff) - lastPathChar(o2);
- if (cPos < bLen)
- return lastPathChar(o1) - (b[cPos] & 0xff);
- return lastPathChar(o1) - lastPathChar(o2);
- }
- };
-
- static int lastPathChar(final Entry e) {
- return e.getMode() == FileMode.TREE ? '/' : '\0';
- }
-
- /**
- * Constructor helper.
- *
- * @param list
- * files in the subtree of the work tree this iterator operates
- * on
- */
- protected void init(final Entry[] list) {
- // Filter out nulls, . and .. as these are not valid tree entries,
- // also cache the encoded forms of the path names for efficient use
- // later on during sorting and iteration.
- //
- entries = list;
- int i, o;
-
- for (i = 0, o = 0; i < entries.length; i++) {
- final Entry e = entries[i];
- if (e == null)
- continue;
- final String name = e.getName();
- if (".".equals(name) || "..".equals(name))
- continue;
- if (Constants.DOT_GIT.equals(name))
- continue;
- if (i != o)
- entries[o] = e;
- e.encodeName(nameEncoder);
- o++;
- }
- entryCnt = o;
- Arrays.sort(entries, 0, entryCnt, ENTRY_CMP);
-
- contentIdFromPtr = -1;
- ptr = 0;
- if (!eof())
- parseEntry();
- }
-
- /**
- * Obtain the current entry from this iterator.
- *
- * @return the currently selected entry.
- */
- protected Entry current() {
- return entries[ptr];
- }
-
- /** A single entry within a working directory tree. */
- protected static abstract class Entry {
- byte[] encodedName;
-
- int encodedNameLen;
-
- void encodeName(final CharsetEncoder enc) {
- final ByteBuffer b;
- try {
- b = enc.encode(CharBuffer.wrap(getName()));
- } catch (CharacterCodingException e) {
- // This should so never happen.
- throw new RuntimeException("Unencodeable file: " + getName());
- }
-
- encodedNameLen = b.limit();
- if (b.hasArray() && b.arrayOffset() == 0)
- encodedName = b.array();
- else
- b.get(encodedName = new byte[encodedNameLen]);
- }
-
- public String toString() {
- return getMode().toString() + " " + getName();
- }
-
- /**
- * Get the type of this entry.
- * <p>
- * <b>Note: Efficient implementation required.</b>
- * <p>
- * The implementation of this method must be efficient. If a subclass
- * needs to compute the value they should cache the reference within an
- * instance member instead.
- *
- * @return a file mode constant from {@link FileMode}.
- */
- public abstract FileMode getMode();
-
- /**
- * Get the byte length of this entry.
- * <p>
- * <b>Note: Efficient implementation required.</b>
- * <p>
- * The implementation of this method must be efficient. If a subclass
- * needs to compute the value they should cache the reference within an
- * instance member instead.
- *
- * @return size of this file, in bytes.
- */
- public abstract long getLength();
-
- /**
- * Get the last modified time of this entry.
- * <p>
- * <b>Note: Efficient implementation required.</b>
- * <p>
- * The implementation of this method must be efficient. If a subclass
- * needs to compute the value they should cache the reference within an
- * instance member instead.
- *
- * @return time since the epoch (in ms) of the last change.
- */
- public abstract long getLastModified();
-
- /**
- * Get the name of this entry within its directory.
- * <p>
- * Efficient implementations are not required. The caller will obtain
- * the name only once and cache it once obtained.
- *
- * @return name of the entry.
- */
- public abstract String getName();
-
- /**
- * Obtain an input stream to read the file content.
- * <p>
- * Efficient implementations are not required. The caller will usually
- * obtain the stream only once per entry, if at all.
- * <p>
- * The input stream should not use buffering if the implementation can
- * avoid it. The caller will buffer as necessary to perform efficient
- * block IO operations.
- * <p>
- * The caller will close the stream once complete.
- *
- * @return a stream to read from the file.
- * @throws IOException
- * the file could not be opened for reading.
- */
- public abstract InputStream openInputStream() throws IOException;
- }
- }
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