com.google.gerrit.server.git.TagCache Maven / Gradle / Ivy
// Copyright (C) 2011 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.git;
import com.google.common.cache.Cache;
import com.google.gerrit.reviewdb.client.Project;
import com.google.gerrit.server.cache.CacheModule;
import com.google.gerrit.server.cache.serialize.StringCacheSerializer;
import com.google.inject.Inject;
import com.google.inject.Module;
import com.google.inject.Singleton;
import com.google.inject.name.Named;
import java.util.concurrent.ExecutionException;
import org.eclipse.jgit.lib.ObjectId;
@Singleton
public class TagCache {
private static final String CACHE_NAME = "git_tags";
public static Module module() {
return new CacheModule() {
@Override
protected void configure() {
persist(CACHE_NAME, String.class, TagSetHolder.class)
.version(1)
.keySerializer(StringCacheSerializer.INSTANCE)
.valueSerializer(TagSetHolder.Serializer.INSTANCE);
bind(TagCache.class);
}
};
}
private final Cache cache;
@Inject
TagCache(@Named(CACHE_NAME) Cache cache) {
this.cache = cache;
}
/**
* Advise the cache that a reference fast-forwarded.
*
* This operation is not necessary, the cache will automatically detect changes made to
* references and update itself on demand. However, this method may allow the cache to update more
* quickly and reuse the caller's computation of the fast-forward status of a branch.
*
* @param name project the branch is contained in.
* @param refName the branch name.
* @param oldValue the old value, before the fast-forward. The cache will only update itself if it
* is still using this old value.
* @param newValue the current value, after the fast-forward.
*/
public void updateFastForward(
Project.NameKey name, String refName, ObjectId oldValue, ObjectId newValue) {
// Be really paranoid and null check everything. This method should
// never fail with an exception. Some of these references can be null
// (e.g. not all projects are cached, or the cache is not current).
//
TagSetHolder holder = cache.getIfPresent(name.get());
if (holder != null) {
TagSet tags = holder.getTagSet();
if (tags != null) {
if (tags.updateFastForward(refName, oldValue, newValue)) {
cache.put(name.get(), holder);
}
}
}
}
public TagSetHolder get(Project.NameKey name) {
try {
return cache.get(name.get(), () -> new TagSetHolder(name));
} catch (ExecutionException e) {
throw new IllegalStateException(e);
}
}
void put(Project.NameKey name, TagSetHolder tags) {
cache.put(name.get(), tags);
}
}