content: /*
   * 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 org.apache.beam.sdk.extensions.avro.io;
  
  import static org.apache.avro.file.DataFileConstants.BZIP2_CODEC;
  import static org.apache.avro.file.DataFileConstants.DEFLATE_CODEC;
  import static org.apache.avro.file.DataFileConstants.NULL_CODEC;
  import static org.apache.avro.file.DataFileConstants.SNAPPY_CODEC;
  import static org.apache.avro.file.DataFileConstants.XZ_CODEC;
  import static org.apache.beam.vendor.guava.v32_1_2_jre.com.google.common.base.Preconditions.checkNotNull;
  import static org.apache.beam.vendor.guava.v32_1_2_jre.com.google.common.base.Preconditions.checkState;
  
  import java.io.Externalizable;
  import java.io.IOException;
  import java.io.ObjectInput;
  import java.io.ObjectOutput;
  import java.util.Arrays;
  import java.util.List;
  import java.util.regex.Matcher;
  import java.util.regex.Pattern;
  import org.apache.avro.file.CodecFactory;
  import org.checkerframework.checker.nullness.qual.Nullable;
  
  /**
   * A wrapper that allows {@link CodecFactory}s to be serialized using Java's standard serialization
   * mechanisms.
   */
  @SuppressWarnings({
    "nullness" // TODO(https://github.com/apache/beam/issues/20497)
  })
  class SerializableAvroCodecFactory implements Externalizable {
    private static final long serialVersionUID = 7445324844109564303L;
    private static final List<String> noOptAvroCodecs =
        Arrays.asList(NULL_CODEC, SNAPPY_CODEC, BZIP2_CODEC);
    private static final Pattern deflatePattern = Pattern.compile(DEFLATE_CODEC + "-(?<level>-?\\d)");
    private static final Pattern xzPattern = Pattern.compile(XZ_CODEC + "-(?<level>\\d)");
  
    // Don't reference `DataFileConstants.ZSTANDARD_CODEC` directly for Avro 1.8 compat
    private static final Pattern zstdPattern = Pattern.compile("zstandard\\[(?<level>-?\\d+)\\]");
  
    private @Nullable CodecFactory codecFactory;
  
    // For java.io.Externalizable
    public SerializableAvroCodecFactory() {}
  
    public SerializableAvroCodecFactory(CodecFactory codecFactory) {
      checkNotNull(codecFactory, "Codec can't be null");
      checkState(checkIsSupportedCodec(codecFactory), "%s is not supported", codecFactory);
      this.codecFactory = codecFactory;
    }
  
    private boolean checkIsSupportedCodec(CodecFactory codecFactory) {
      final String codecStr = codecFactory.toString();
      return noOptAvroCodecs.contains(codecStr)
          || deflatePattern.matcher(codecStr).matches()
          || xzPattern.matcher(codecStr).matches()
          || zstdPattern.matcher(codecStr).matches();
    }
  
    @Override
    public void writeExternal(ObjectOutput out) throws IOException {
      out.writeUTF(codecFactory.toString());
    }
  
    @Override
    public void readExternal(ObjectInput in) throws IOException, ClassNotFoundException {
      final String codecStr = in.readUTF();
  
      switch (codecStr) {
        case NULL_CODEC:
        case SNAPPY_CODEC:
        case BZIP2_CODEC:
          codecFactory = CodecFactory.fromString(codecStr);
          return;
      }
  
      Matcher deflateMatcher = deflatePattern.matcher(codecStr);
      if (deflateMatcher.find()) {
        codecFactory = CodecFactory.deflateCodec(Integer.parseInt(deflateMatcher.group("level")));
        return;
      }
  
      Matcher xzMatcher = xzPattern.matcher(codecStr);
      if (xzMatcher.find()) {
        codecFactory = CodecFactory.xzCodec(Integer.parseInt(xzMatcher.group("level")));
        return;
      }
  
      Matcher zstdMatcher = zstdPattern.matcher(codecStr);
      if (zstdMatcher.find()) {
        codecFactory = CodecFactory.zstandardCodec(Integer.parseInt(zstdMatcher.group("level")));
        return;
      }
  
      throw new IllegalStateException(codecStr + " is not supported");
    }
  
    public CodecFactory getCodec() {
      return codecFactory;
    }
  
    @Override
    public String toString() {
      checkNotNull(codecFactory, "Inner CodecFactory is null, please use non default constructor");
      return codecFactory.toString();
    }
  }
  