| // Copyright 2018 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.skyframe.serialization; |
| |
| import static sun.misc.Unsafe.ARRAY_OBJECT_BASE_OFFSET; |
| import static sun.misc.Unsafe.ARRAY_OBJECT_INDEX_SCALE; |
| |
| import com.google.common.collect.Sets; |
| import com.google.protobuf.CodedInputStream; |
| import com.google.protobuf.CodedOutputStream; |
| import java.io.IOException; |
| import java.util.Collections; |
| import java.util.HashSet; |
| import java.util.LinkedHashSet; |
| import java.util.concurrent.atomic.AtomicInteger; |
| |
| /** |
| * {@link ObjectCodec} for {@link HashSet} that returns {@link LinkedHashSet} for determinism. |
| * |
| * <p>This type transformation is safe because {@link LinkedHashSet} is a subclass of {@link |
| * HashSet}. |
| */ |
| @SuppressWarnings({"rawtypes", "unchecked", "NonApiType"}) |
| final class HashSetCodec extends AsyncObjectCodec<HashSet> { |
| @Override |
| public Class<HashSet> getEncodedClass() { |
| return HashSet.class; |
| } |
| |
| @Override |
| public void serialize(SerializationContext context, HashSet obj, CodedOutputStream codedOut) |
| throws SerializationException, IOException { |
| codedOut.writeInt32NoTag(obj.size()); |
| for (Object object : obj) { |
| context.serialize(object, codedOut); |
| } |
| } |
| |
| @Override |
| public HashSet deserializeAsync(AsyncDeserializationContext context, CodedInputStream codedIn) |
| throws SerializationException, IOException { |
| int size = codedIn.readInt32(); |
| LinkedHashSet set = Sets.newLinkedHashSetWithExpectedSize(size); |
| context.registerInitialValue(set); |
| |
| if (size == 0) { |
| return set; |
| } |
| |
| ElementBuffer buffer = new ElementBuffer(set, size); |
| for (int i = 0; i < size; i++) { |
| context.deserialize( |
| codedIn, |
| buffer.elements, |
| ARRAY_OBJECT_BASE_OFFSET + ARRAY_OBJECT_INDEX_SCALE * i, |
| /* done= */ (Runnable) buffer); |
| } |
| |
| return set; |
| } |
| |
| /** |
| * Buffers the elements and populates the set once all are available. |
| * |
| * <p>This approach is implicitly thread-safe. |
| */ |
| private static class ElementBuffer implements Runnable { |
| private final LinkedHashSet set; |
| private final Object[] elements; |
| |
| private final AtomicInteger remaining; |
| |
| private ElementBuffer(LinkedHashSet set, int size) { |
| this.set = set; |
| this.elements = new Object[size]; |
| |
| this.remaining = new AtomicInteger(size); |
| } |
| |
| @Override |
| public void run() { |
| if (remaining.decrementAndGet() == 0) { |
| Collections.addAll(set, elements); |
| } |
| } |
| } |
| } |