ObjectId.java
/*
* Copyright (C) 2008, Robin Rosenberg <robin.rosenberg@dewire.com>
* Copyright (C) 2006-2008, Shawn O. Pearce <spearce@spearce.org> 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 java.io.IOException;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.io.Serializable;
import org.eclipse.jgit.annotations.Nullable;
import org.eclipse.jgit.errors.InvalidObjectIdException;
import org.eclipse.jgit.util.NB;
import org.eclipse.jgit.util.RawParseUtils;
/**
* A SHA-1 abstraction.
*/
public class ObjectId extends AnyObjectId implements Serializable {
private static final long serialVersionUID = 1L;
private static final ObjectId ZEROID;
private static final String ZEROID_STR;
static {
ZEROID = new ObjectId(0, 0, 0, 0, 0);
ZEROID_STR = ZEROID.name();
}
/**
* Get the special all-null ObjectId.
*
* @return the all-null ObjectId, often used to stand-in for no object.
*/
public static final ObjectId zeroId() {
return ZEROID;
}
/**
* Test a string of characters to verify it is a hex format.
* <p>
* If true the string can be parsed with {@link #fromString(String)}.
*
* @param id
* the string to test.
* @return true if the string can converted into an ObjectId.
*/
public static final boolean isId(@Nullable String id) {
if (id == null) {
return false;
}
if (id.length() != Constants.OBJECT_ID_STRING_LENGTH)
return false;
try {
for (int i = 0; i < Constants.OBJECT_ID_STRING_LENGTH; i++) {
RawParseUtils.parseHexInt4((byte) id.charAt(i));
}
return true;
} catch (ArrayIndexOutOfBoundsException e) {
return false;
}
}
/**
* Convert an ObjectId into a hex string representation.
*
* @param i
* the id to convert. May be null.
* @return the hex string conversion of this id's content.
*/
public static final String toString(ObjectId i) {
return i != null ? i.name() : ZEROID_STR;
}
/**
* Compare two object identifier byte sequences for equality.
*
* @param firstBuffer
* the first buffer to compare against. Must have at least 20
* bytes from position fi through the end of the buffer.
* @param fi
* first offset within firstBuffer to begin testing.
* @param secondBuffer
* the second buffer to compare against. Must have at least 20
* bytes from position si through the end of the buffer.
* @param si
* first offset within secondBuffer to begin testing.
* @return true if the two identifiers are the same.
*/
public static boolean equals(final byte[] firstBuffer, final int fi,
final byte[] secondBuffer, final int si) {
return firstBuffer[fi] == secondBuffer[si]
&& firstBuffer[fi + 1] == secondBuffer[si + 1]
&& firstBuffer[fi + 2] == secondBuffer[si + 2]
&& firstBuffer[fi + 3] == secondBuffer[si + 3]
&& firstBuffer[fi + 4] == secondBuffer[si + 4]
&& firstBuffer[fi + 5] == secondBuffer[si + 5]
&& firstBuffer[fi + 6] == secondBuffer[si + 6]
&& firstBuffer[fi + 7] == secondBuffer[si + 7]
&& firstBuffer[fi + 8] == secondBuffer[si + 8]
&& firstBuffer[fi + 9] == secondBuffer[si + 9]
&& firstBuffer[fi + 10] == secondBuffer[si + 10]
&& firstBuffer[fi + 11] == secondBuffer[si + 11]
&& firstBuffer[fi + 12] == secondBuffer[si + 12]
&& firstBuffer[fi + 13] == secondBuffer[si + 13]
&& firstBuffer[fi + 14] == secondBuffer[si + 14]
&& firstBuffer[fi + 15] == secondBuffer[si + 15]
&& firstBuffer[fi + 16] == secondBuffer[si + 16]
&& firstBuffer[fi + 17] == secondBuffer[si + 17]
&& firstBuffer[fi + 18] == secondBuffer[si + 18]
&& firstBuffer[fi + 19] == secondBuffer[si + 19];
}
/**
* Convert an ObjectId from raw binary representation.
*
* @param bs
* the raw byte buffer to read from. At least 20 bytes must be
* available within this byte array.
* @return the converted object id.
*/
public static final ObjectId fromRaw(byte[] bs) {
return fromRaw(bs, 0);
}
/**
* Convert an ObjectId from raw binary representation.
*
* @param bs
* the raw byte buffer to read from. At least 20 bytes after p
* must be available within this byte array.
* @param p
* position to read the first byte of data from.
* @return the converted object id.
*/
public static final ObjectId fromRaw(byte[] bs, int p) {
final int a = NB.decodeInt32(bs, p);
final int b = NB.decodeInt32(bs, p + 4);
final int c = NB.decodeInt32(bs, p + 8);
final int d = NB.decodeInt32(bs, p + 12);
final int e = NB.decodeInt32(bs, p + 16);
return new ObjectId(a, b, c, d, e);
}
/**
* Convert an ObjectId from raw binary representation.
*
* @param is
* the raw integers buffer to read from. At least 5 integers must
* be available within this int array.
* @return the converted object id.
*/
public static final ObjectId fromRaw(int[] is) {
return fromRaw(is, 0);
}
/**
* Convert an ObjectId from raw binary representation.
*
* @param is
* the raw integers buffer to read from. At least 5 integers
* after p must be available within this int array.
* @param p
* position to read the first integer of data from.
* @return the converted object id.
*/
public static final ObjectId fromRaw(int[] is, int p) {
return new ObjectId(is[p], is[p + 1], is[p + 2], is[p + 3], is[p + 4]);
}
/**
* Convert an ObjectId from hex characters (US-ASCII).
*
* @param buf
* the US-ASCII buffer to read from. At least 40 bytes after
* offset must be available within this byte array.
* @param offset
* position to read the first character from.
* @return the converted object id.
*/
public static final ObjectId fromString(byte[] buf, int offset) {
return fromHexString(buf, offset);
}
/**
* Convert an ObjectId from hex characters.
*
* @param str
* the string to read from. Must be 40 characters long.
* @return the converted object id.
*/
public static ObjectId fromString(String str) {
if (str.length() != Constants.OBJECT_ID_STRING_LENGTH) {
throw new InvalidObjectIdException(str);
}
return fromHexString(Constants.encodeASCII(str), 0);
}
private static final ObjectId fromHexString(byte[] bs, int p) {
try {
final int a = RawParseUtils.parseHexInt32(bs, p);
final int b = RawParseUtils.parseHexInt32(bs, p + 8);
final int c = RawParseUtils.parseHexInt32(bs, p + 16);
final int d = RawParseUtils.parseHexInt32(bs, p + 24);
final int e = RawParseUtils.parseHexInt32(bs, p + 32);
return new ObjectId(a, b, c, d, e);
} catch (ArrayIndexOutOfBoundsException e) {
InvalidObjectIdException e1 = new InvalidObjectIdException(bs, p,
Constants.OBJECT_ID_STRING_LENGTH);
e1.initCause(e);
throw e1;
}
}
/**
* Construct an ObjectId from 160 bits provided in 5 words.
*
* @param new_1
* an int
* @param new_2
* an int
* @param new_3
* an int
* @param new_4
* an int
* @param new_5
* an int
* @since 4.7
*/
public ObjectId(int new_1, int new_2, int new_3, int new_4, int new_5) {
w1 = new_1;
w2 = new_2;
w3 = new_3;
w4 = new_4;
w5 = new_5;
}
/**
* Initialize this instance by copying another existing ObjectId.
* <p>
* This constructor is mostly useful for subclasses who want to extend an
* ObjectId with more properties, but initialize from an existing ObjectId
* instance acquired by other means.
*
* @param src
* another already parsed ObjectId to copy the value out of.
*/
protected ObjectId(AnyObjectId src) {
w1 = src.w1;
w2 = src.w2;
w3 = src.w3;
w4 = src.w4;
w5 = src.w5;
}
/** {@inheritDoc} */
@Override
public ObjectId toObjectId() {
return this;
}
private void writeObject(ObjectOutputStream os) throws IOException {
os.writeInt(w1);
os.writeInt(w2);
os.writeInt(w3);
os.writeInt(w4);
os.writeInt(w5);
}
private void readObject(ObjectInputStream ois) throws IOException {
w1 = ois.readInt();
w2 = ois.readInt();
w3 = ois.readInt();
w4 = ois.readInt();
w5 = ois.readInt();
}
}