| // 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 com.google.protobuf.CodedInputStream; |
| import com.google.protobuf.CodedOutputStream; |
| import java.io.IOException; |
| import java.util.Collections; |
| import java.util.HashMap; |
| import java.util.LinkedHashMap; |
| import java.util.Map; |
| |
| /** {@link ObjectCodec} for {@link java.util.Collections.UnmodifiableMap}. */ |
| final class UnmodifiableMapCodec<K, V> implements ObjectCodec<Map<K, V>> { |
| private final Map<K, V> empty = Collections.unmodifiableMap(new HashMap<>()); |
| |
| @SuppressWarnings("unchecked") |
| @Override |
| public Class<Map<K, V>> getEncodedClass() { |
| return (Class<Map<K, V>>) empty.getClass(); |
| } |
| |
| @Override |
| public void serialize(SerializationContext context, Map<K, V> obj, CodedOutputStream codedOut) |
| throws SerializationException, IOException { |
| codedOut.writeInt32NoTag(obj.size()); |
| for (Map.Entry<K, V> entry : obj.entrySet()) { |
| context.serialize(entry.getKey(), codedOut); |
| context.serialize(entry.getValue(), codedOut); |
| } |
| } |
| |
| @Override |
| public Map<K, V> deserialize(DeserializationContext context, CodedInputStream codedIn) |
| throws SerializationException, IOException { |
| int size = codedIn.readInt32(); |
| if (size == 0) { |
| return empty; |
| } |
| // Load factor is 0.75, so we need an initial capacity of 4/3 actual size to avoid rehashing. |
| LinkedHashMap<K, V> result = new LinkedHashMap<>(4 * size / 3); |
| for (int i = 0; i < size; i++) { |
| result.put(context.deserialize(codedIn), context.deserialize(codedIn)); |
| } |
| return Collections.unmodifiableMap(result); |
| } |
| |
| } |