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// Copyright (C) 2018 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.notedb;
import static java.nio.charset.StandardCharsets.UTF_8;
import static org.eclipse.jgit.lib.Constants.OBJ_BLOB;
import com.google.auto.value.AutoValue;
import com.google.common.annotations.VisibleForTesting;
import com.google.common.base.CharMatcher;
import com.google.common.flogger.FluentLogger;
import com.google.common.primitives.Ints;
import com.google.gerrit.common.Nullable;
import com.google.gerrit.entities.Project;
import com.google.gerrit.exceptions.StorageException;
import com.google.gerrit.git.RefUpdateUtil;
import com.google.gerrit.server.extensions.events.GitReferenceUpdated;
import java.io.IOException;
import java.util.Optional;
import org.eclipse.jgit.errors.IncorrectObjectTypeException;
import org.eclipse.jgit.lib.AnyObjectId;
import org.eclipse.jgit.lib.ObjectId;
import org.eclipse.jgit.lib.ObjectInserter;
import org.eclipse.jgit.lib.ObjectLoader;
import org.eclipse.jgit.lib.ObjectReader;
import org.eclipse.jgit.lib.Ref;
import org.eclipse.jgit.lib.RefUpdate;
import org.eclipse.jgit.lib.Repository;
import org.eclipse.jgit.revwalk.RevWalk;
/** An object blob in a Git repository that stores a single integer value. */
@AutoValue
public abstract class IntBlob {
private static final FluentLogger logger = FluentLogger.forEnclosingClass();
public static Optional<IntBlob> parse(Repository repo, String refName) throws IOException {
try (ObjectReader or = repo.newObjectReader()) {
return parse(repo, refName, or);
}
}
public static Optional<IntBlob> parse(Repository repo, String refName, RevWalk rw)
throws IOException {
return parse(repo, refName, rw.getObjectReader());
}
private static Optional<IntBlob> parse(Repository repo, String refName, ObjectReader or)
throws IOException {
Ref ref = repo.exactRef(refName);
if (ref == null) {
return Optional.empty();
}
ObjectId id = ref.getObjectId();
ObjectLoader ol = or.open(id, OBJ_BLOB);
if (ol.getType() != OBJ_BLOB) {
// In theory this should be thrown by open but not all implementations may do it properly
// (certainly InMemoryRepository doesn't).
throw new IncorrectObjectTypeException(id, OBJ_BLOB);
}
String str = CharMatcher.whitespace().trimFrom(new String(ol.getCachedBytes(), UTF_8));
Integer value = Ints.tryParse(str);
if (value == null) {
throw new StorageException("invalid value in " + refName + " blob at " + id.name());
}
return Optional.of(IntBlob.create(id, value));
}
public static RefUpdate tryStore(
Repository repo,
RevWalk rw,
Project.NameKey projectName,
String refName,
@Nullable ObjectId oldId,
int val,
GitReferenceUpdated gitRefUpdated)
throws IOException {
ObjectId newId;
try (ObjectInserter ins = repo.newObjectInserter()) {
logger.atFine().log(
"storing value %d on %s in %s (oldId: %s)",
val, refName, projectName, oldId == null ? "null" : oldId.name());
newId = ins.insert(OBJ_BLOB, Integer.toString(val).getBytes(UTF_8));
ins.flush();
logger.atFine().log(
"successfully stored %d on %s as %s in %s", val, refName, newId.name(), projectName);
}
RefUpdate ru = repo.updateRef(refName);
if (oldId != null) {
ru.setExpectedOldObjectId(oldId);
}
ru.disableRefLog();
ru.setNewObjectId(newId);
ru.setForceUpdate(true); // Required for non-commitish updates.
RefUpdate.Result result = ru.update(rw);
if (refUpdated(result)) {
gitRefUpdated.fire(projectName, ru, null);
}
return ru;
}
public static void store(
Repository repo,
RevWalk rw,
Project.NameKey projectName,
String refName,
@Nullable ObjectId oldId,
int val,
GitReferenceUpdated gitRefUpdated)
throws IOException {
RefUpdateUtil.checkResult(tryStore(repo, rw, projectName, refName, oldId, val, gitRefUpdated));
}
private static boolean refUpdated(RefUpdate.Result result) {
return result == RefUpdate.Result.NEW || result == RefUpdate.Result.FORCED;
}
@VisibleForTesting
static IntBlob create(AnyObjectId id, int value) {
return new AutoValue_IntBlob(id.copy(), value);
}
public abstract ObjectId id();
public abstract int value();
}