ByteStringTypeAdapter.java

/*
 * Copyright 2022 Proto Utils Authors
 *
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements. See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership. The ASF licenses this file
 * to you 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 net.morimekta.proto.gson.adapter;

import com.google.gson.JsonParseException;
import com.google.gson.TypeAdapter;
import com.google.gson.stream.JsonReader;
import com.google.gson.stream.JsonToken;
import com.google.gson.stream.JsonWriter;
import com.google.protobuf.ByteString;

import java.io.IOException;

import static net.morimekta.proto.utils.ByteStringUtil.fromBase64;
import static net.morimekta.proto.utils.ByteStringUtil.toBase64;

/**
 * Adapter for handling byte strings.
 */
public class ByteStringTypeAdapter extends TypeAdapter<ByteString> {
    /** {@inheritDoc} */
    @Override
    public void write(JsonWriter jsonWriter, ByteString bytes) throws IOException {
        jsonWriter.value(toBase64(bytes));
    }

    /** {@inheritDoc} */
    @Override
    public ByteString read(JsonReader jsonReader) throws IOException {
        if (jsonReader.peek() == JsonToken.NULL) {
            jsonReader.nextNull();
            return null;
        }
        try {
            return fromBase64(jsonReader.nextString());
        } catch (IllegalArgumentException e) {
            throw new JsonParseException(
                    "Invalid base64 at " + jsonReader.getPreviousPath() + ": " + e.getMessage(), e);
        }
    }
}