Java tutorial
/* * Copyright (C) 2010, Google Inc. * 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.lib; import static org.eclipse.jgit.lib.Constants.OBJECT_ID_LENGTH; import static org.eclipse.jgit.lib.Constants.OBJ_TREE; import static org.eclipse.jgit.lib.Constants.encode; import static org.eclipse.jgit.lib.FileMode.GITLINK; import static org.eclipse.jgit.lib.FileMode.REGULAR_FILE; import static org.eclipse.jgit.lib.FileMode.TREE; import java.io.IOException; import org.eclipse.jgit.errors.CorruptObjectException; import org.eclipse.jgit.internal.JGitText; import org.eclipse.jgit.revwalk.RevBlob; import org.eclipse.jgit.revwalk.RevCommit; import org.eclipse.jgit.revwalk.RevTree; import org.eclipse.jgit.treewalk.CanonicalTreeParser; import org.eclipse.jgit.util.TemporaryBuffer; /** * Mutable formatter to construct a single tree object. * * This formatter does not process subtrees. Callers must handle creating each * subtree on their own. * * To maintain good performance for bulk operations, this formatter does not * validate its input. Callers are responsible for ensuring the resulting tree * object is correctly well formed by writing entries in the correct order. */ public class TreeFormatter { /** * Compute the size of a tree entry record. * * This method can be used to estimate the correct size of a tree prior to * allocating a formatter. Getting the size correct at allocation time * ensures the internal buffer is sized correctly, reducing copying. * * @param mode * the mode the entry will have. * @param nameLen * the length of the name, in bytes. * @return the length of the record. */ public static int entrySize(FileMode mode, int nameLen) { return mode.copyToLength() + nameLen + OBJECT_ID_LENGTH + 2; } private byte[] buf; private int ptr; private TemporaryBuffer.Heap overflowBuffer; /** * Create an empty formatter with a default buffer size. */ public TreeFormatter() { this(8192); } /** * Create an empty formatter with the specified buffer size. * * @param size * estimated size of the tree, in bytes. Callers can use * {@link #entrySize(FileMode, int)} to estimate the size of each * entry in advance of allocating the formatter. */ public TreeFormatter(int size) { buf = new byte[size]; } /** * Add a link to a submodule commit, mode is {@link org.eclipse.jgit.lib.FileMode#GITLINK}. * * @param name * name of the entry. * @param commit * the ObjectId to store in this entry. */ public void append(String name, RevCommit commit) { append(name, GITLINK, commit); } /** * Add a subtree, mode is {@link org.eclipse.jgit.lib.FileMode#TREE}. * * @param name * name of the entry. * @param tree * the ObjectId to store in this entry. */ public void append(String name, RevTree tree) { append(name, TREE, tree); } /** * Add a regular file, mode is {@link org.eclipse.jgit.lib.FileMode#REGULAR_FILE}. * * @param name * name of the entry. * @param blob * the ObjectId to store in this entry. */ public void append(String name, RevBlob blob) { append(name, REGULAR_FILE, blob); } /** * Append any entry to the tree. * * @param name * name of the entry. * @param mode * mode describing the treatment of {@code id}. * @param id * the ObjectId to store in this entry. */ public void append(String name, FileMode mode, AnyObjectId id) { append(encode(name), mode, id); } /** * Append any entry to the tree. * * @param name * name of the entry. The name should be UTF-8 encoded, but file * name encoding is not a well defined concept in Git. * @param mode * mode describing the treatment of {@code id}. * @param id * the ObjectId to store in this entry. */ public void append(byte[] name, FileMode mode, AnyObjectId id) { append(name, 0, name.length, mode, id); } /** * Append any entry to the tree. * * @param nameBuf * buffer holding the name of the entry. The name should be UTF-8 * encoded, but file name encoding is not a well defined concept * in Git. * @param namePos * first position within {@code nameBuf} of the name data. * @param nameLen * number of bytes from {@code nameBuf} to use as the name. * @param mode * mode describing the treatment of {@code id}. * @param id * the ObjectId to store in this entry. */ public void append(byte[] nameBuf, int namePos, int nameLen, FileMode mode, AnyObjectId id) { append(nameBuf, namePos, nameLen, mode, id, false); } /** * Append any entry to the tree. * * @param nameBuf * buffer holding the name of the entry. The name should be UTF-8 * encoded, but file name encoding is not a well defined concept * in Git. * @param namePos * first position within {@code nameBuf} of the name data. * @param nameLen * number of bytes from {@code nameBuf} to use as the name. * @param mode * mode describing the treatment of {@code id}. * @param id * the ObjectId to store in this entry. * @param allowEmptyName * allow an empty filename (creating a corrupt tree) * @since 4.6 */ public void append(byte[] nameBuf, int namePos, int nameLen, FileMode mode, AnyObjectId id, boolean allowEmptyName) { if (nameLen == 0 && !allowEmptyName) { throw new IllegalArgumentException(JGitText.get().invalidTreeZeroLengthName); } if (fmtBuf(nameBuf, namePos, nameLen, mode)) { id.copyRawTo(buf, ptr); ptr += OBJECT_ID_LENGTH; } else { try { fmtOverflowBuffer(nameBuf, namePos, nameLen, mode); id.copyRawTo(overflowBuffer); } catch (IOException badBuffer) { // This should never occur. throw new RuntimeException(badBuffer); } } } /** * Append any entry to the tree. * * @param nameBuf * buffer holding the name of the entry. The name should be UTF-8 * encoded, but file name encoding is not a well defined concept * in Git. * @param namePos * first position within {@code nameBuf} of the name data. * @param nameLen * number of bytes from {@code nameBuf} to use as the name. * @param mode * mode describing the treatment of {@code id}. * @param idBuf * buffer holding the raw ObjectId of the entry. * @param idPos * first position within {@code idBuf} to copy the id from. */ public void append(byte[] nameBuf, int namePos, int nameLen, FileMode mode, byte[] idBuf, int idPos) { if (fmtBuf(nameBuf, namePos, nameLen, mode)) { System.arraycopy(idBuf, idPos, buf, ptr, OBJECT_ID_LENGTH); ptr += OBJECT_ID_LENGTH; } else { try { fmtOverflowBuffer(nameBuf, namePos, nameLen, mode); overflowBuffer.write(idBuf, idPos, OBJECT_ID_LENGTH); } catch (IOException badBuffer) { // This should never occur. throw new RuntimeException(badBuffer); } } } private boolean fmtBuf(byte[] nameBuf, int namePos, int nameLen, FileMode mode) { if (buf == null || buf.length < ptr + entrySize(mode, nameLen)) return false; mode.copyTo(buf, ptr); ptr += mode.copyToLength(); buf[ptr++] = ' '; System.arraycopy(nameBuf, namePos, buf, ptr, nameLen); ptr += nameLen; buf[ptr++] = 0; return true; } private void fmtOverflowBuffer(byte[] nameBuf, int namePos, int nameLen, FileMode mode) throws IOException { if (buf != null) { overflowBuffer = new TemporaryBuffer.Heap(Integer.MAX_VALUE); overflowBuffer.write(buf, 0, ptr); buf = null; } mode.copyTo(overflowBuffer); overflowBuffer.write((byte) ' '); overflowBuffer.write(nameBuf, namePos, nameLen); overflowBuffer.write((byte) 0); } /** * Insert this tree and obtain its ObjectId. * * @param ins * the inserter to store the tree. * @return computed ObjectId of the tree * @throws java.io.IOException * the tree could not be stored. */ public ObjectId insertTo(ObjectInserter ins) throws IOException { if (buf != null) return ins.insert(OBJ_TREE, buf, 0, ptr); final long len = overflowBuffer.length(); return ins.insert(OBJ_TREE, len, overflowBuffer.openInputStream()); } /** * Compute the ObjectId for this tree * * @param ins a {@link org.eclipse.jgit.lib.ObjectInserter} object. * @return ObjectId for this tree */ public ObjectId computeId(ObjectInserter ins) { if (buf != null) return ins.idFor(OBJ_TREE, buf, 0, ptr); final long len = overflowBuffer.length(); try { return ins.idFor(OBJ_TREE, len, overflowBuffer.openInputStream()); } catch (IOException e) { // this should never happen throw new RuntimeException(e); } } /** * Copy this formatter's buffer into a byte array. * * This method is not efficient, as it needs to create a copy of the * internal buffer in order to supply an array of the correct size to the * caller. If the buffer is just to pass to an ObjectInserter, consider * using {@link org.eclipse.jgit.lib.ObjectInserter#insert(TreeFormatter)} * instead. * * @return a copy of this formatter's buffer. */ public byte[] toByteArray() { if (buf != null) { byte[] r = new byte[ptr]; System.arraycopy(buf, 0, r, 0, ptr); return r; } try { return overflowBuffer.toByteArray(); } catch (IOException err) { // This should never happen, its read failure on a byte array. throw new RuntimeException(err); } } /** {@inheritDoc} */ @SuppressWarnings("nls") @Override public String toString() { byte[] raw = toByteArray(); CanonicalTreeParser p = new CanonicalTreeParser(); p.reset(raw); StringBuilder r = new StringBuilder(); r.append("Tree={"); if (!p.eof()) { r.append('\n'); try { new ObjectChecker().checkTree(raw); } catch (CorruptObjectException error) { r.append("*** ERROR: ").append(error.getMessage()).append("\n"); r.append('\n'); } } while (!p.eof()) { final FileMode mode = p.getEntryFileMode(); r.append(mode); r.append(' '); r.append(Constants.typeString(mode.getObjectType())); r.append(' '); r.append(p.getEntryObjectId().name()); r.append(' '); r.append(p.getEntryPathString()); r.append('\n'); p.next(); } r.append("}"); return r.toString(); } }