Line data    Source code

       1             : // Copyright (C) 2011 The Android Open Source Project
       2             : //
       3             : // Licensed under the Apache License, Version 2.0 (the "License");
       4             : // you may not use this file except in compliance with the License.
       5             : // You may obtain a copy of the License at
       6             : //
       7             : // http://www.apache.org/licenses/LICENSE-2.0
       8             : //
       9             : // Unless required by applicable law or agreed to in writing, software
      10             : // distributed under the License is distributed on an "AS IS" BASIS,
      11             : // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
      12             : // See the License for the specific language governing permissions and
      13             : // limitations under the License.
      14             : 
      15             : package com.google.gerrit.server.git;
      16             : 
      17             : import com.google.common.cache.Cache;
      18             : import com.google.gerrit.entities.Project;
      19             : import com.google.gerrit.server.cache.CacheModule;
      20             : import com.google.gerrit.server.cache.serialize.StringCacheSerializer;
      21             : import com.google.inject.Inject;
      22             : import com.google.inject.Module;
      23             : import com.google.inject.Singleton;
      24             : import com.google.inject.name.Named;
      25             : import java.util.concurrent.ExecutionException;
      26             : import org.eclipse.jgit.lib.ObjectId;
      27             : 
      28             : @Singleton
      29             : public class TagCache {
      30             :   private static final String CACHE_NAME = "git_tags";
      31             : 
      32             :   public static Module module() {
      33         152 :     return new CacheModule() {
      34             :       @Override
      35             :       protected void configure() {
      36         152 :         persist(CACHE_NAME, String.class, TagSetHolder.class)
      37         152 :             .version(1)
      38         152 :             .keySerializer(StringCacheSerializer.INSTANCE)
      39         152 :             .valueSerializer(TagSetHolder.Serializer.INSTANCE);
      40         152 :         bind(TagCache.class);
      41         152 :       }
      42             :     };
      43             :   }
      44             : 
      45             :   private final Cache<String, TagSetHolder> cache;
      46             : 
      47             :   @Inject
      48         143 :   TagCache(@Named(CACHE_NAME) Cache<String, TagSetHolder> cache) {
      49         143 :     this.cache = cache;
      50         143 :   }
      51             : 
      52             :   /**
      53             :    * Advise the cache that a reference fast-forwarded.
      54             :    *
      55             :    * <p>This operation is not necessary, the cache will automatically detect changes made to
      56             :    * references and update itself on demand. However, this method may allow the cache to update more
      57             :    * quickly and reuse the caller's computation of the fast-forward status of a branch.
      58             :    *
      59             :    * @param name project the branch is contained in.
      60             :    * @param refName the branch name.
      61             :    * @param oldValue the old value, before the fast-forward. The cache will only update itself if it
      62             :    *     is still using this old value.
      63             :    * @param newValue the current value, after the fast-forward.
      64             :    */
      65             :   public void updateFastForward(
      66             :       Project.NameKey name, String refName, ObjectId oldValue, ObjectId newValue) {
      67             :     // Be really paranoid and null check everything. This method should
      68             :     // never fail with an exception. Some of these references can be null
      69             :     // (e.g. not all projects are cached, or the cache is not current).
      70             :     //
      71          68 :     TagSetHolder holder = cache.getIfPresent(name.get());
      72          68 :     if (holder != null) {
      73           5 :       TagSet tags = holder.getTagSet();
      74           5 :       if (tags != null) {
      75           5 :         if (tags.updateFastForward(refName, oldValue, newValue)) {
      76           5 :           cache.put(name.get(), holder);
      77             :         }
      78             :       }
      79             :     }
      80          68 :   }
      81             : 
      82             :   public TagSetHolder get(Project.NameKey name) {
      83             :     try {
      84           9 :       return cache.get(name.get(), () -> new TagSetHolder(name));
      85           0 :     } catch (ExecutionException e) {
      86           0 :       throw new IllegalStateException(e);
      87             :     }
      88             :   }
      89             : 
      90             :   void put(Project.NameKey name, TagSetHolder tags) {
      91           9 :     cache.put(name.get(), tags);
      92           9 :   }
      93             : }