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// Copyright (C) 2017 The Android Open Source Project
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package com.google.gerrit.server.util;
import static java.nio.charset.StandardCharsets.UTF_8;
import com.google.common.base.Strings;
import com.google.gerrit.common.Nullable;
import com.google.gerrit.entities.Change;
import com.google.gerrit.extensions.restapi.BadRequestException;
import java.security.NoSuchAlgorithmException;
import java.security.SecureRandom;
import java.util.Optional;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
import org.eclipse.jgit.lib.Constants;
import org.eclipse.jgit.lib.ObjectId;
import org.eclipse.jgit.lib.ObjectInserter;
import org.eclipse.jgit.util.ChangeIdUtil;
/** Utility functions to manipulate commit messages. */
public class CommitMessageUtil {
private static final SecureRandom rng;
private static final Pattern changeIdFooterPattern =
Pattern.compile("Change-Id: *(I[a-f0-9]{40})");
static {
try {
rng = SecureRandom.getInstance("SHA1PRNG");
} catch (NoSuchAlgorithmException e) {
throw new IllegalStateException("Cannot create RNG for Change-Id generator", e);
}
}
private CommitMessageUtil() {}
/**
* Checks for invalid (empty or containing \0) commit messages and appends a newline character to
* the commit message.
*
* @throws BadRequestException if the commit message is null or empty
* @return the trimmed message with a trailing newline character
*/
public static String checkAndSanitizeCommitMessage(@Nullable String commitMessage)
throws BadRequestException {
String trimmed = Strings.nullToEmpty(commitMessage).trim();
if (trimmed.isEmpty()) {
throw new BadRequestException("Commit message cannot be null or empty");
}
if (trimmed.indexOf(0) >= 0) {
throw new BadRequestException("Commit message cannot have NUL character");
}
trimmed = trimmed + "\n";
return trimmed;
}
public static ObjectId generateChangeId() {
byte[] rand = new byte[Constants.OBJECT_ID_STRING_LENGTH];
rng.nextBytes(rand);
String randomString = new String(rand, UTF_8);
try (ObjectInserter f = new ObjectInserter.Formatter()) {
return f.idFor(Constants.OBJ_COMMIT, Constants.encode(randomString));
}
}
public static Change.Key generateKey() {
return Change.key(getChangeIdFromObjectId(generateChangeId()));
}
public static String getChangeIdFromObjectId(ObjectId objectId) {
return "I" + objectId.name();
}
/**
* Return the value of Change-Id from the commit message footer.
*
* <p>The behaviour matches {@link org.eclipse.jgit.util.ChangeIdUtil}. If more than one matching
* Change-Id footer is found, return the value of the last one.
*
* @param commitMessage commit message to get Change-Id from.
* @return {@link Optional} value of Change-Id footer in the commit message.
*/
public static Optional<String> getChangeIdFromCommitMessageFooter(String commitMessage) {
int indexOfChangeId = ChangeIdUtil.indexOfChangeId(commitMessage, "\n");
if (indexOfChangeId == -1) {
return Optional.empty();
}
Matcher matcher = changeIdFooterPattern.matcher(commitMessage);
if (matcher.find(indexOfChangeId)) {
return Optional.of(matcher.group(1));
}
return Optional.empty();
}
}