| // Copyright 2019 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.runtime; |
| |
| import com.google.common.util.concurrent.Uninterruptibles; |
| import com.google.devtools.build.lib.buildeventstream.ArtifactGroupNamer; |
| import com.google.devtools.build.lib.buildeventstream.BuildEventStreamProtos.BuildEventId.NamedSetOfFilesId; |
| import com.google.devtools.build.lib.collect.nestedset.NestedSet; |
| import java.util.concurrent.ConcurrentHashMap; |
| import java.util.concurrent.ConcurrentMap; |
| import java.util.concurrent.CountDownLatch; |
| import javax.annotation.Nullable; |
| import javax.annotation.concurrent.ThreadSafe; |
| |
| /** Conversion of paths to URIs. */ |
| @ThreadSafe |
| public class CountingArtifactGroupNamer implements ArtifactGroupNamer { |
| |
| private final ConcurrentMap<NestedSet.Node, LatchedGroupName> nodeNames = |
| new ConcurrentHashMap<>(); |
| |
| @Override |
| @Nullable |
| public NamedSetOfFilesId apply(NestedSet.Node id) { |
| LatchedGroupName name = nodeNames.get(id); |
| if (name == null) { |
| return null; |
| } |
| return NamedSetOfFilesId.newBuilder().setId(name.getName()).build(); |
| } |
| |
| /** |
| * If the {@link NestedSet} has no name already, return a new name for it. Return null otherwise. |
| */ |
| @Nullable |
| public LatchedGroupName maybeName(NestedSet<?> set) { |
| NestedSet.Node id = set.toNode(); |
| LatchedGroupName existingGroupName; |
| LatchedGroupName newGroupName; |
| // synchronized necessary only to ensure node names are chosen uniquely and compactly. |
| // TODO(adgar): consider dropping compactness and unconditionally increment an AtomicLong to |
| // pick unique node names. |
| synchronized (this) { |
| newGroupName = new LatchedGroupName(nodeNames.size()); |
| existingGroupName = nodeNames.putIfAbsent(id, newGroupName); |
| } |
| if (existingGroupName != null) { |
| existingGroupName.waitUntilWritten(); |
| return null; |
| } |
| return newGroupName; |
| } |
| |
| /** |
| * A name for a {@code NestedSet<?>} that the constructor must {@link #close()} after the set is |
| * written, allowing all other consumers to {@link #waitUntilWritten()}. |
| */ |
| public static class LatchedGroupName implements AutoCloseable { |
| private final CountDownLatch latch; |
| private final int name; |
| |
| public LatchedGroupName(int name) { |
| this.latch = new CountDownLatch(1); |
| this.name = name; |
| } |
| |
| @Override |
| public void close() { |
| latch.countDown(); |
| } |
| |
| String getName() { |
| return Integer.toString(name); |
| } |
| |
| private void waitUntilWritten() { |
| Uninterruptibles.awaitUninterruptibly(latch); |
| } |
| } |
| } |