RevTag.java
/*
* Copyright (C) 2008, 2009, Google Inc.
* Copyright (C) 2008, Marek Zawirski <marek.zawirski@gmail.com>
* Copyright (C) 2008, 2021, 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.revwalk;
import static java.nio.charset.StandardCharsets.UTF_8;
import java.io.IOException;
import java.nio.charset.Charset;
import java.nio.charset.IllegalCharsetNameException;
import java.nio.charset.UnsupportedCharsetException;
import java.util.Arrays;
import org.eclipse.jgit.annotations.Nullable;
import org.eclipse.jgit.errors.CorruptObjectException;
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.ObjectInserter;
import org.eclipse.jgit.lib.ObjectReader;
import org.eclipse.jgit.lib.PersonIdent;
import org.eclipse.jgit.util.MutableInteger;
import org.eclipse.jgit.util.RawParseUtils;
import org.eclipse.jgit.util.StringUtils;
/**
* An annotated tag.
*/
public class RevTag extends RevObject {
private static final byte[] hSignature = Constants
.encodeASCII("-----BEGIN PGP SIGNATURE-----"); //$NON-NLS-1$
/**
* Parse an annotated tag from its canonical format.
*
* This method constructs a temporary revision pool, parses the tag as
* supplied, and returns it to the caller. Since the tag was built inside of
* a private revision pool its object pointer will be initialized, but will
* not have its headers loaded.
*
* Applications are discouraged from using this API. Callers usually need
* more than one object. Use
* {@link org.eclipse.jgit.revwalk.RevWalk#parseTag(AnyObjectId)} to obtain
* a RevTag from an existing repository.
*
* @param raw
* the canonical formatted tag to be parsed.
* @return the parsed tag, in an isolated revision pool that is not
* available to the caller.
* @throws org.eclipse.jgit.errors.CorruptObjectException
* the tag contains a malformed header that cannot be handled.
*/
public static RevTag parse(byte[] raw) throws CorruptObjectException {
return parse(new RevWalk((ObjectReader) null), raw);
}
/**
* Parse an annotated tag from its canonical format.
* <p>
* This method inserts the tag directly into the caller supplied revision
* pool, making it appear as though the tag exists in the repository, even
* if it doesn't. The repository under the pool is not affected.
* <p>
* The body of the tag (message, tagger, signature) is always retained in
* the returned {@code RevTag}, even if the supplied {@code RevWalk} has
* been configured with {@code setRetainBody(false)}.
*
* @param rw
* the revision pool to allocate the tag within. The tag's object
* pointer will be obtained from this pool.
* @param raw
* the canonical formatted tag to be parsed. This buffer will be
* retained by the returned {@code RevTag} and must not be
* modified by the caller.
* @return the parsed tag, in an isolated revision pool that is not
* available to the caller.
* @throws org.eclipse.jgit.errors.CorruptObjectException
* the tag contains a malformed header that cannot be handled.
*/
public static RevTag parse(RevWalk rw, byte[] raw)
throws CorruptObjectException {
try (ObjectInserter.Formatter fmt = new ObjectInserter.Formatter()) {
RevTag r = rw.lookupTag(fmt.idFor(Constants.OBJ_TAG, raw));
r.parseCanonical(rw, raw);
r.buffer = raw;
return r;
}
}
private RevObject object;
private byte[] buffer;
private String tagName;
/**
* Create a new tag reference.
*
* @param id
* object name for the tag.
*/
protected RevTag(AnyObjectId id) {
super(id);
}
@Override
void parseHeaders(RevWalk walk) throws MissingObjectException,
IncorrectObjectTypeException, IOException {
parseCanonical(walk, walk.getCachedBytes(this));
}
@Override
void parseBody(RevWalk walk) throws MissingObjectException,
IncorrectObjectTypeException, IOException {
if (buffer == null) {
buffer = walk.getCachedBytes(this);
if ((flags & PARSED) == 0)
parseCanonical(walk, buffer);
}
}
void parseCanonical(RevWalk walk, byte[] rawTag)
throws CorruptObjectException {
final MutableInteger pos = new MutableInteger();
final int oType;
pos.value = 53; // "object $sha1\ntype "
oType = Constants.decodeTypeString(this, rawTag, (byte) '\n', pos);
walk.idBuffer.fromString(rawTag, 7);
object = walk.lookupAny(walk.idBuffer, oType);
int p = pos.value += 4; // "tag "
final int nameEnd = RawParseUtils.nextLF(rawTag, p) - 1;
tagName = RawParseUtils.decode(UTF_8, rawTag, p, nameEnd);
if (walk.isRetainBody())
buffer = rawTag;
flags |= PARSED;
}
/** {@inheritDoc} */
@Override
public final int getType() {
return Constants.OBJ_TAG;
}
/**
* Parse the tagger identity from the raw buffer.
* <p>
* This method parses and returns the content of the tagger line, after
* taking the tag's character set into account and decoding the tagger
* name and email address. This method is fairly expensive and produces a
* new PersonIdent instance on each invocation. Callers should invoke this
* method only if they are certain they will be outputting the result, and
* should cache the return value for as long as necessary to use all
* information from it.
*
* @return identity of the tagger (name, email) and the time the tag
* was made by the tagger; null if no tagger line was found.
*/
public final PersonIdent getTaggerIdent() {
final byte[] raw = buffer;
final int nameB = RawParseUtils.tagger(raw, 0);
if (nameB < 0)
return null;
return RawParseUtils.parsePersonIdent(raw, nameB);
}
private static int nextStart(byte[] prefix, byte[] buffer, int from) {
int stop = buffer.length - prefix.length + 1;
int ptr = from;
if (ptr > 0) {
ptr = RawParseUtils.nextLF(buffer, ptr - 1);
}
while (ptr < stop) {
int lineStart = ptr;
boolean found = true;
for (byte element : prefix) {
if (element != buffer[ptr++]) {
found = false;
break;
}
}
if (found) {
return lineStart;
}
do {
ptr = RawParseUtils.nextLF(buffer, ptr);
} while (ptr < stop && buffer[ptr] == '\n');
}
return -1;
}
private int getSignatureStart() {
byte[] raw = buffer;
int msgB = RawParseUtils.tagMessage(raw, 0);
if (msgB < 0) {
return msgB;
}
// Find the last signature start and return the rest
int start = nextStart(hSignature, raw, msgB);
if (start < 0) {
return start;
}
int next = RawParseUtils.nextLF(raw, start);
while (next < raw.length) {
int newStart = nextStart(hSignature, raw, next);
if (newStart < 0) {
break;
}
start = newStart;
next = RawParseUtils.nextLF(raw, start);
}
return start;
}
/**
* Parse the GPG signature from the raw buffer.
*
* @return contents of the GPG signature; {@code null} if the tag was not
* signed.
* @since 5.11
*/
@Nullable
public final byte[] getRawGpgSignature() {
byte[] raw = buffer;
int start = getSignatureStart();
if (start < 0) {
return null;
}
return Arrays.copyOfRange(raw, start, raw.length);
}
/**
* Parse the complete tag message and decode it to a string.
* <p>
* This method parses and returns the message portion of the tag buffer,
* after taking the tag's character set into account and decoding the buffer
* using that character set. This method is a fairly expensive operation and
* produces a new string on each invocation.
*
* @return decoded tag message as a string. Never null.
*/
public final String getFullMessage() {
byte[] raw = buffer;
int msgB = RawParseUtils.tagMessage(raw, 0);
if (msgB < 0) {
return ""; //$NON-NLS-1$
}
int signatureStart = getSignatureStart();
int end = signatureStart < 0 ? raw.length : signatureStart;
if (end == msgB) {
return ""; //$NON-NLS-1$
}
return RawParseUtils.decode(guessEncoding(), raw, msgB, end);
}
/**
* Parse the tag message and return the first "line" of it.
* <p>
* The first line is everything up to the first pair of LFs. This is the
* "oneline" format, suitable for output in a single line display.
* <p>
* This method parses and returns the message portion of the tag buffer,
* after taking the tag's character set into account and decoding the buffer
* using that character set. This method is a fairly expensive operation and
* produces a new string on each invocation.
*
* @return decoded tag message as a string. Never null. The returned string
* does not contain any LFs, even if the first paragraph spanned
* multiple lines. Embedded LFs are converted to spaces.
*/
public final String getShortMessage() {
byte[] raw = buffer;
int msgB = RawParseUtils.tagMessage(raw, 0);
if (msgB < 0) {
return ""; //$NON-NLS-1$
}
int msgE = RawParseUtils.endOfParagraph(raw, msgB);
int signatureStart = getSignatureStart();
if (signatureStart >= msgB && msgE > signatureStart) {
msgE = signatureStart;
if (msgE > msgB) {
msgE--;
}
if (msgB == msgE) {
return ""; //$NON-NLS-1$
}
}
String str = RawParseUtils.decode(guessEncoding(), raw, msgB, msgE);
if (RevCommit.hasLF(raw, msgB, msgE)) {
str = StringUtils.replaceLineBreaksWithSpace(str);
}
return str;
}
private Charset guessEncoding() {
try {
return RawParseUtils.parseEncoding(buffer);
} catch (IllegalCharsetNameException | UnsupportedCharsetException e) {
return UTF_8;
}
}
/**
* Get a reference to the object this tag was placed on.
* <p>
* Note that the returned object has only been looked up (see
* {@link org.eclipse.jgit.revwalk.RevWalk#lookupAny(AnyObjectId, int)}. To
* access the contents it needs to be parsed, see
* {@link org.eclipse.jgit.revwalk.RevWalk#parseHeaders(RevObject)} and
* {@link org.eclipse.jgit.revwalk.RevWalk#parseBody(RevObject)}.
* <p>
* As an alternative, use
* {@link org.eclipse.jgit.revwalk.RevWalk#peel(RevObject)} and pass this
* {@link org.eclipse.jgit.revwalk.RevTag} to peel it until the first
* non-tag object.
*
* @return object this tag refers to (only looked up, not parsed)
*/
public final RevObject getObject() {
return object;
}
/**
* Get the name of this tag, from the tag header.
*
* @return name of the tag, according to the tag header.
*/
public final String getTagName() {
return tagName;
}
/**
* Obtain the raw unparsed tag body (<b>NOTE - THIS IS NOT A COPY</b>).
* <p>
* This method is exposed only to provide very fast, efficient access to
* this tag's message buffer. Applications relying on this buffer should be
* very careful to ensure they do not modify its contents during their use
* of it.
*
* @return the raw unparsed tag body. This is <b>NOT A COPY</b>. Do not
* alter the returned array.
* @since 5.11
*/
public final byte[] getRawBuffer() {
return buffer;
}
/**
* Discard the message buffer to reduce memory usage.
* <p>
* After discarding the memory usage of the {@code RevTag} is reduced to
* only the {@link #getObject()} pointer and {@link #getTagName()}.
* Accessing other properties such as {@link #getTaggerIdent()} or either
* message function requires reloading the buffer by invoking
* {@link org.eclipse.jgit.revwalk.RevWalk#parseBody(RevObject)}.
*
* @since 4.0
*/
public final void disposeBody() {
buffer = null;
}
}