| // 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; |
| |
| 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.inject.Inject; |
| import com.google.inject.Module; |
| import com.google.inject.Singleton; |
| import com.google.inject.name.Named; |
| |
| import org.eclipse.jgit.lib.ObjectId; |
| |
| import java.io.IOException; |
| import java.io.ObjectInputStream; |
| import java.io.ObjectOutputStream; |
| import java.io.Serializable; |
| |
| @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, EntryVal.class); |
| bind(TagCache.class); |
| } |
| }; |
| } |
| |
| private final Cache<String, EntryVal> cache; |
| private final Object createLock = new Object(); |
| |
| @Inject |
| TagCache(@Named(CACHE_NAME) Cache<String, EntryVal> cache) { |
| this.cache = cache; |
| } |
| |
| /** |
| * Advise the cache that a reference fast-forwarded. |
| * <p> |
| * 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). |
| // |
| EntryVal val = cache.getIfPresent(name.get()); |
| if (val != null) { |
| TagSetHolder holder = val.holder; |
| if (holder != null) { |
| TagSet tags = holder.getTagSet(); |
| if (tags != null) { |
| if (tags.updateFastForward(refName, oldValue, newValue)) { |
| cache.put(name.get(), val); |
| } |
| } |
| } |
| } |
| } |
| |
| TagSetHolder get(Project.NameKey name) { |
| EntryVal val = cache.getIfPresent(name.get()); |
| if (val == null) { |
| synchronized (createLock) { |
| val = cache.getIfPresent(name.get()); |
| if (val == null) { |
| val = new EntryVal(); |
| val.holder = new TagSetHolder(name); |
| cache.put(name.get(), val); |
| } |
| } |
| } |
| return val.holder; |
| } |
| |
| void put(Project.NameKey name, TagSetHolder tags) { |
| EntryVal val = new EntryVal(); |
| val.holder = tags; |
| cache.put(name.get(), val); |
| } |
| |
| static class EntryVal implements Serializable { |
| static final long serialVersionUID = 1L; |
| |
| transient TagSetHolder holder; |
| |
| private void readObject(ObjectInputStream in) throws IOException, |
| ClassNotFoundException { |
| holder = new TagSetHolder(new Project.NameKey(in.readUTF())); |
| if (in.readBoolean()) { |
| TagSet tags = new TagSet(holder.getProjectName()); |
| tags.readObject(in); |
| holder.setTagSet(tags); |
| } |
| } |
| |
| private void writeObject(ObjectOutputStream out) throws IOException { |
| TagSet tags = holder.getTagSet(); |
| out.writeUTF(holder.getProjectName().get()); |
| out.writeBoolean(tags != null); |
| if (tags != null) { |
| tags.writeObject(out); |
| } |
| } |
| } |
| } |