com.google.devtools.build.lib.skyframe.serialization.ImmutableListCodec.java Source code

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Here is the source code for com.google.devtools.build.lib.skyframe.serialization.ImmutableListCodec.java

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// Copyright 2017 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.common.collect.ImmutableList;
import com.google.protobuf.CodedInputStream;
import com.google.protobuf.CodedOutputStream;
import java.io.IOException;

/** Encodes a list of elements using a specified {@link ObjectCodec}. */
public class ImmutableListCodec<T> implements ObjectCodec<ImmutableList<T>> {

    private final ObjectCodec<T> codec;

    public ImmutableListCodec(ObjectCodec<T> codec) {
        this.codec = codec;
    }

    @SuppressWarnings("unchecked")
    @Override
    public Class<ImmutableList<T>> getEncodedClass() {
        // Compiler doesn't like cast from Class<ImmutableList> -> Class<ImmutableList<T>>, but it
        // does allow what we see below. Type is lost at runtime anyway, so while gross this works.
        return (Class<ImmutableList<T>>) ((Class<?>) ImmutableList.class);
    }

    @Override
    public void serialize(ImmutableList<T> list, CodedOutputStream codedOut)
            throws SerializationException, IOException {
        codedOut.writeInt32NoTag(list.size());
        for (T item : list) {
            codec.serialize(item, codedOut);
        }
    }

    @Override
    public ImmutableList<T> deserialize(CodedInputStream codedIn) throws SerializationException, IOException {
        int length = codedIn.readInt32();
        if (length < 0) {
            throw new SerializationException("Expected non-negative length: " + length);
        }

        ImmutableList.Builder<T> builder = ImmutableList.builder();
        for (int i = 0; i < length; i++) {
            builder.add(codec.deserialize(codedIn));
        }
        return builder.build();
    }
}