| // 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 com.google.devtools.build.lib.skyframe.serialization.MapHelpers.deserializeMapEntries; |
| import static com.google.devtools.build.lib.skyframe.serialization.MapHelpers.serializeMapEntries; |
| |
| import com.google.protobuf.CodedInputStream; |
| import com.google.protobuf.CodedOutputStream; |
| import java.io.IOException; |
| import java.util.HashMap; |
| import java.util.LinkedHashMap; |
| |
| /** |
| * {@link ObjectCodec} for {@link HashMap} that returns {@link LinkedHashMap} for determinism. |
| * |
| * <p>This type transformation is safe because {@link LinkedHashMap} is a subclass of {@link |
| * HashMap}. |
| */ |
| @SuppressWarnings({"unchecked", "rawtypes", "NonApiType"}) |
| final class HashMapCodec extends AsyncObjectCodec<HashMap> { |
| @Override |
| public Class<HashMap> getEncodedClass() { |
| return HashMap.class; |
| } |
| |
| @Override |
| public void serialize(SerializationContext context, HashMap obj, CodedOutputStream codedOut) |
| throws SerializationException, IOException { |
| codedOut.writeInt32NoTag(obj.size()); |
| serializeMapEntries(context, obj, codedOut); |
| } |
| |
| @Override |
| public HashMap deserializeAsync(AsyncDeserializationContext context, CodedInputStream codedIn) |
| throws SerializationException, IOException { |
| int size = codedIn.readInt32(); |
| // Load factor is 0.75, so we need an initial capacity of 4/3 actual size to avoid rehashing. |
| LinkedHashMap result = new LinkedHashMap(4 * size / 3); |
| |
| context.registerInitialValue(result); |
| if (size == 0) { |
| return result; |
| } |
| |
| populateMap(context, codedIn, result, size); |
| |
| return result; |
| } |
| |
| static void populateMap( |
| AsyncDeserializationContext context, CodedInputStream codedIn, LinkedHashMap map, int size) |
| throws SerializationException, IOException { |
| EntryBuffer buffer = new EntryBuffer(map, size); |
| deserializeMapEntries( |
| context, codedIn, buffer.keys, buffer.values, /* done= */ (Runnable) buffer); |
| } |
| |
| /** |
| * Buffers the keys and values until all are available, then populates the map. |
| * |
| * <p>This approach is thread-safe. |
| */ |
| private static class EntryBuffer implements Runnable { |
| private final LinkedHashMap result; |
| private final Object[] keys; |
| private final Object[] values; |
| |
| private EntryBuffer(LinkedHashMap result, int size) { |
| this.result = result; |
| this.keys = new Object[size]; |
| this.values = new Object[size]; |
| } |
| |
| @Override |
| public void run() { |
| for (int i = 0; i < keys.length; i++) { |
| result.put(keys[i], values[i]); |
| } |
| } |
| } |
| } |