| // Copyright 2014 The Bazel Authors. All rights reserved. |
| // |
| // 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.devtools.build.lib.actions; |
| |
| import com.google.common.collect.ImmutableList; |
| import com.google.common.collect.Iterables; |
| import com.google.common.collect.MapMaker; |
| |
| import java.util.ArrayList; |
| import java.util.List; |
| import java.util.concurrent.ConcurrentMap; |
| import java.util.concurrent.locks.ReadWriteLock; |
| import java.util.concurrent.locks.ReentrantReadWriteLock; |
| |
| /** |
| * A registry that keeps a map of artifacts to unique integer ids. |
| */ |
| class ArtifactIdRegistry implements ArtifactSerializer, ArtifactDeserializer { |
| |
| /** |
| * A sequence of registered artifacts. The position in the list is the artifact's id. |
| * |
| * <p>Synchronized using {@link #artifactIdsLock}. |
| */ |
| private final List<Artifact> serializedArtifactList = new ArrayList<>(); |
| |
| /** |
| * A map of artifacts to unique integer ids. |
| * |
| * <p>Writes to this map must be synchronized using {@link #artifactIdsLock}, in order to |
| * maintain consistency with {@link #serializedArtifactList}. |
| */ |
| private final ConcurrentMap<Artifact, Integer> serializedArtifactIds = |
| new MapMaker().concurrencyLevel(1).makeMap(); |
| |
| /** |
| * A lock for keeping {@code serializedArtifactList} and {@code serializedArtifactIds} in sync. |
| */ |
| private ReadWriteLock artifactIdsLock = new ReentrantReadWriteLock(); |
| |
| ArtifactIdRegistry() { |
| } |
| |
| @Override |
| public int getArtifactId(Artifact artifact) { |
| Integer artifactId = serializedArtifactIds.get(artifact); |
| if (artifactId == null) { |
| artifactId = assignArtifactId(artifact); |
| } |
| return artifactId; |
| } |
| |
| private Integer assignArtifactId(Artifact artifact) { |
| artifactIdsLock.writeLock().lock(); |
| try { |
| Integer artifactId = serializedArtifactIds.get(artifact); |
| if (artifactId == null) { |
| artifactId = serializedArtifactList.size(); |
| serializedArtifactList.add(artifact); |
| serializedArtifactIds.put(artifact, artifactId); |
| } |
| return artifactId; |
| } finally { |
| artifactIdsLock.writeLock().unlock(); |
| } |
| } |
| |
| @Override |
| public Artifact lookupArtifactById(int artifactId) { |
| artifactIdsLock.readLock().lock(); |
| try { |
| return serializedArtifactList.get(artifactId); |
| } finally { |
| artifactIdsLock.readLock().unlock(); |
| } |
| } |
| |
| @Override |
| public ImmutableList<Artifact> lookupArtifactsByIds(Iterable<Integer> artifactIds) { |
| int size = Iterables.size(artifactIds); |
| Artifact[] result = new Artifact[size]; |
| |
| int i = 0; |
| |
| artifactIdsLock.readLock().lock(); |
| try { |
| for (int artifactId : artifactIds) { |
| result[i] = serializedArtifactList.get(artifactId); |
| i++; |
| } |
| } finally { |
| artifactIdsLock.readLock().unlock(); |
| } |
| |
| return ImmutableList.copyOf(result); |
| } |
| } |