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- /*
- * Copyright (C) 2008-2010, Google Inc.
- * 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.util.Arrays;
-
- import org.eclipse.jgit.errors.IncorrectObjectTypeException;
- import org.eclipse.jgit.errors.MissingObjectException;
- import org.eclipse.jgit.lib.AnyObjectId;
- import org.eclipse.jgit.lib.Constants;
- import org.eclipse.jgit.lib.FileMode;
- import org.eclipse.jgit.lib.MutableObjectId;
- import org.eclipse.jgit.lib.ObjectId;
- import org.eclipse.jgit.lib.ObjectLoader;
- import org.eclipse.jgit.lib.Repository;
- import org.eclipse.jgit.lib.WindowCursor;
-
- /** Parses raw Git trees from the canonical semi-text/semi-binary format. */
- public class CanonicalTreeParser extends AbstractTreeIterator {
- private static final byte[] EMPTY = {};
-
- private byte[] raw;
-
- /** First offset within {@link #raw} of the prior entry. */
- private int prevPtr;
-
- /** First offset within {@link #raw} of the current entry's data. */
- private int currPtr;
-
- /** Offset one past the current entry (first byte of next entry). */
- private int nextPtr;
-
- /** Create a new parser. */
- public CanonicalTreeParser() {
- reset(EMPTY);
- }
-
- /**
- * Create a new parser for a tree appearing in a subset of a repository.
- *
- * @param prefix
- * position of this iterator in the repository tree. The value
- * may be null or the empty array to indicate the prefix is the
- * root of the repository. A trailing slash ('/') is
- * automatically appended if the prefix does not end in '/'.
- * @param repo
- * repository to load the tree data from.
- * @param treeId
- * identity of the tree being parsed; used only in exception
- * messages if data corruption is found.
- * @param curs
- * a window cursor to use during data access from the repository.
- * @throws MissingObjectException
- * the object supplied is not available from the repository.
- * @throws IncorrectObjectTypeException
- * the object supplied as an argument is not actually a tree and
- * cannot be parsed as though it were a tree.
- * @throws IOException
- * a loose object or pack file could not be read.
- */
- public CanonicalTreeParser(final byte[] prefix, final Repository repo,
- final AnyObjectId treeId, final WindowCursor curs)
- throws IncorrectObjectTypeException, IOException {
- super(prefix);
- reset(repo, treeId, curs);
- }
-
- private CanonicalTreeParser(final CanonicalTreeParser p) {
- super(p);
- }
-
- /**
- * Reset this parser to walk through the given tree data.
- *
- * @param treeData
- * the raw tree content.
- */
- public void reset(final byte[] treeData) {
- raw = treeData;
- prevPtr = -1;
- currPtr = 0;
- if (eof())
- nextPtr = 0;
- else
- parseEntry();
- }
-
- /**
- * Reset this parser to walk through the given tree.
- *
- * @param repo
- * repository to load the tree data from.
- * @param id
- * identity of the tree being parsed; used only in exception
- * messages if data corruption is found.
- * @param curs
- * window cursor to use during repository access.
- * @return the root level parser.
- * @throws MissingObjectException
- * the object supplied is not available from the repository.
- * @throws IncorrectObjectTypeException
- * the object supplied as an argument is not actually a tree and
- * cannot be parsed as though it were a tree.
- * @throws IOException
- * a loose object or pack file could not be read.
- */
- public CanonicalTreeParser resetRoot(final Repository repo,
- final AnyObjectId id, final WindowCursor curs)
- throws IncorrectObjectTypeException, IOException {
- CanonicalTreeParser p = this;
- while (p.parent != null)
- p = (CanonicalTreeParser) p.parent;
- p.reset(repo, id, curs);
- return p;
- }
-
- /** @return this iterator, or its parent, if the tree is at eof. */
- public CanonicalTreeParser next() {
- CanonicalTreeParser p = this;
- for (;;) {
- if (p.nextPtr == p.raw.length) {
- // This parser has reached EOF, return to the parent.
- if (p.parent == null) {
- p.currPtr = p.nextPtr;
- return p;
- }
- p = (CanonicalTreeParser) p.parent;
- continue;
- }
-
- p.prevPtr = p.currPtr;
- p.currPtr = p.nextPtr;
- p.parseEntry();
- return p;
- }
- }
-
- /**
- * Reset this parser to walk through the given tree.
- *
- * @param repo
- * repository to load the tree data from.
- * @param id
- * identity of the tree being parsed; used only in exception
- * messages if data corruption is found.
- * @param curs
- * window cursor to use during repository access.
- * @throws MissingObjectException
- * the object supplied is not available from the repository.
- * @throws IncorrectObjectTypeException
- * the object supplied as an argument is not actually a tree and
- * cannot be parsed as though it were a tree.
- * @throws IOException
- * a loose object or pack file could not be read.
- */
- public void reset(final Repository repo, final AnyObjectId id,
- final WindowCursor curs)
- throws IncorrectObjectTypeException, IOException {
- final ObjectLoader ldr = repo.openObject(curs, id);
- if (ldr == null) {
- final ObjectId me = id.toObjectId();
- throw new MissingObjectException(me, Constants.TYPE_TREE);
- }
- final byte[] subtreeData = ldr.getCachedBytes();
- if (ldr.getType() != Constants.OBJ_TREE) {
- final ObjectId me = id.toObjectId();
- throw new IncorrectObjectTypeException(me, Constants.TYPE_TREE);
- }
- reset(subtreeData);
- }
-
- @Override
- public CanonicalTreeParser createSubtreeIterator(final Repository repo,
- final MutableObjectId idBuffer, final WindowCursor curs)
- throws IncorrectObjectTypeException, IOException {
- idBuffer.fromRaw(idBuffer(), idOffset());
- if (!FileMode.TREE.equals(mode)) {
- final ObjectId me = idBuffer.toObjectId();
- throw new IncorrectObjectTypeException(me, Constants.TYPE_TREE);
- }
- return createSubtreeIterator0(repo, idBuffer, curs);
- }
-
- /**
- * Back door to quickly create a subtree iterator for any subtree.
- * <p>
- * Don't use this unless you are ObjectWalk. The method is meant to be
- * called only once the current entry has been identified as a tree and its
- * identity has been converted into an ObjectId.
- *
- * @param repo
- * repository to load the tree data from.
- * @param id
- * ObjectId of the tree to open.
- * @param curs
- * window cursor to use during repository access.
- * @return a new parser that walks over the current subtree.
- * @throws IOException
- * a loose object or pack file could not be read.
- */
- public final CanonicalTreeParser createSubtreeIterator0(
- final Repository repo, final AnyObjectId id, final WindowCursor curs)
- throws IOException {
- final CanonicalTreeParser p = new CanonicalTreeParser(this);
- p.reset(repo, id, curs);
- return p;
- }
-
- public CanonicalTreeParser createSubtreeIterator(final Repository repo)
- throws IncorrectObjectTypeException, IOException {
- final WindowCursor curs = new WindowCursor();
- try {
- return createSubtreeIterator(repo, new MutableObjectId(), curs);
- } finally {
- curs.release();
- }
- }
-
- @Override
- public byte[] idBuffer() {
- return raw;
- }
-
- @Override
- public int idOffset() {
- return nextPtr - Constants.OBJECT_ID_LENGTH;
- }
-
- @Override
- public boolean first() {
- return currPtr == 0;
- }
-
- public boolean eof() {
- return currPtr == raw.length;
- }
-
- @Override
- public void next(int delta) {
- if (delta == 1) {
- // Moving forward one is the most common case.
- //
- prevPtr = currPtr;
- currPtr = nextPtr;
- if (!eof())
- parseEntry();
- return;
- }
-
- // Fast skip over records, then parse the last one.
- //
- final int end = raw.length;
- int ptr = nextPtr;
- while (--delta > 0 && ptr != end) {
- prevPtr = ptr;
- while (raw[ptr] != 0)
- ptr++;
- ptr += Constants.OBJECT_ID_LENGTH + 1;
- }
- if (delta != 0)
- throw new ArrayIndexOutOfBoundsException(delta);
- currPtr = ptr;
- if (!eof())
- parseEntry();
- }
-
- @Override
- public void back(int delta) {
- if (delta == 1 && 0 <= prevPtr) {
- // Moving back one is common in NameTreeWalk, as the average tree
- // won't have D/F type conflicts to study.
- //
- currPtr = prevPtr;
- prevPtr = -1;
- if (!eof())
- parseEntry();
- return;
- } else if (delta <= 0)
- throw new ArrayIndexOutOfBoundsException(delta);
-
- // Fast skip through the records, from the beginning of the tree.
- // There is no reliable way to read the tree backwards, so we must
- // parse all over again from the beginning. We hold the last "delta"
- // positions in a buffer, so we can find the correct position later.
- //
- final int[] trace = new int[delta + 1];
- Arrays.fill(trace, -1);
- int ptr = 0;
- while (ptr != currPtr) {
- System.arraycopy(trace, 1, trace, 0, delta);
- trace[delta] = ptr;
- while (raw[ptr] != 0)
- ptr++;
- ptr += Constants.OBJECT_ID_LENGTH + 1;
- }
- if (trace[1] == -1)
- throw new ArrayIndexOutOfBoundsException(delta);
- prevPtr = trace[0];
- currPtr = trace[1];
- parseEntry();
- }
-
- private void parseEntry() {
- int ptr = currPtr;
- byte c = raw[ptr++];
- int tmp = c - '0';
- for (;;) {
- c = raw[ptr++];
- if (' ' == c)
- break;
- tmp <<= 3;
- tmp += c - '0';
- }
- mode = tmp;
-
- tmp = pathOffset;
- for (;; tmp++) {
- c = raw[ptr++];
- if (c == 0)
- break;
- try {
- path[tmp] = c;
- } catch (ArrayIndexOutOfBoundsException e) {
- growPath(tmp);
- path[tmp] = c;
- }
- }
- pathLen = tmp;
- nextPtr = ptr + Constants.OBJECT_ID_LENGTH;
- }
- }
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