com.google.gerrit.server.update.RefUpdateUtil Maven / Gradle / Ivy
// 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.update;
import com.google.common.annotations.VisibleForTesting;
import com.google.gerrit.server.git.LockFailureException;
import java.io.IOException;
import org.eclipse.jgit.internal.JGitText;
import org.eclipse.jgit.lib.BatchRefUpdate;
import org.eclipse.jgit.lib.NullProgressMonitor;
import org.eclipse.jgit.lib.RefUpdate;
import org.eclipse.jgit.lib.Repository;
import org.eclipse.jgit.revwalk.RevWalk;
import org.eclipse.jgit.transport.ReceiveCommand;
/** Static utilities for working with JGit's ref update APIs. */
public class RefUpdateUtil {
/**
* Execute a batch ref update, throwing a checked exception if not all updates succeeded.
*
* Creates a new {@link RevWalk} used only for this operation.
*
* @param bru batch update; should already have been executed.
* @param repo repository that created {@code bru}.
* @throws LockFailureException if the transaction was aborted due to lock failure; see {@link
* #checkResults(BatchRefUpdate)} for details.
* @throws IOException if any result was not {@code OK}.
*/
public static void executeChecked(BatchRefUpdate bru, Repository repo) throws IOException {
try (RevWalk rw = new RevWalk(repo)) {
executeChecked(bru, rw);
}
}
/**
* Execute a batch ref update, throwing a checked exception if not all updates succeeded.
*
* @param bru batch update; should already have been executed.
* @param rw walk for executing the update.
* @throws LockFailureException if the transaction was aborted due to lock failure; see {@link
* #checkResults(BatchRefUpdate)} for details.
* @throws IOException if any result was not {@code OK}.
*/
public static void executeChecked(BatchRefUpdate bru, RevWalk rw) throws IOException {
bru.execute(rw, NullProgressMonitor.INSTANCE);
checkResults(bru);
}
/**
* Check results of all commands in the update batch, reducing to a single exception if there was
* a failure.
*
*
Throws {@link LockFailureException} if at least one command failed with {@code
* LOCK_FAILURE}, and the entire transaction was aborted, i.e. any non-{@code LOCK_FAILURE}
* results, if there were any, failed with "transaction aborted".
*
*
In particular, if the underlying ref database does not {@link
* org.eclipse.jgit.lib.RefDatabase#performsAtomicTransactions() perform atomic transactions},
* then a combination of {@code LOCK_FAILURE} on one ref and {@code OK} or another result on other
* refs will not throw {@code LockFailureException}.
*
* @param bru batch update; should already have been executed.
* @throws LockFailureException if the transaction was aborted due to lock failure.
* @throws IOException if any result was not {@code OK}.
*/
@VisibleForTesting
static void checkResults(BatchRefUpdate bru) throws IOException {
if (bru.getCommands().isEmpty()) {
return;
}
int lockFailure = 0;
int aborted = 0;
int failure = 0;
for (ReceiveCommand cmd : bru.getCommands()) {
if (cmd.getResult() != ReceiveCommand.Result.OK) {
failure++;
}
if (cmd.getResult() == ReceiveCommand.Result.LOCK_FAILURE) {
lockFailure++;
} else if (cmd.getResult() == ReceiveCommand.Result.REJECTED_OTHER_REASON
&& JGitText.get().transactionAborted.equals(cmd.getMessage())) {
aborted++;
}
}
if (lockFailure + aborted == bru.getCommands().size()) {
throw new LockFailureException("Update aborted with one or more lock failures: " + bru, bru);
} else if (failure > 0) {
throw new IOException("Update failed: " + bru);
}
}
/**
* Delete a single ref, throwing a checked exception on failure.
*
*
Does not require that the ref have any particular old value. Succeeds as a no-op if the ref
* did not exist.
*
* @param repo repository.
* @param refName ref name to delete.
* @throws LockFailureException if a low-level lock failure (e.g. compare-and-swap failure)
* occurs.
* @throws IOException if an error occurred.
*/
public static void deleteChecked(Repository repo, String refName) throws IOException {
RefUpdate ru = repo.updateRef(refName);
ru.setForceUpdate(true);
switch (ru.delete()) {
case FORCED:
// Ref was deleted.
return;
case NEW:
// Ref didn't exist (yes, really).
return;
case LOCK_FAILURE:
throw new LockFailureException("Failed to delete " + refName + ": " + ru.getResult(), ru);
// Not really failures, but should not be the result of a deletion, so the best option is to
// throw.
case NO_CHANGE:
case FAST_FORWARD:
case RENAMED:
case NOT_ATTEMPTED:
case IO_FAILURE:
case REJECTED:
case REJECTED_CURRENT_BRANCH:
case REJECTED_MISSING_OBJECT:
case REJECTED_OTHER_REASON:
default:
throw new IOException("Failed to delete " + refName + ": " + ru.getResult());
}
}
private RefUpdateUtil() {}
}