TreeFormatter.java
/*
* Copyright (C) 2010, Google Inc. and others
*
* This program and the accompanying materials are made available under the
* terms of the Eclipse Distribution License v. 1.0 which is available at
* https://www.eclipse.org/org/documents/edl-v10.php.
*
* SPDX-License-Identifier: BSD-3-Clause
*/
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();
}
}