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/**
 * 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.orc.impl;

import static org.apache.orc.impl.ReaderImpl.extractMetadata;

import java.io.IOException;
import java.nio.ByteBuffer;
import java.util.ArrayList;
import java.util.List;

import org.apache.orc.CompressionCodec;
import org.apache.orc.CompressionKind;
import org.apache.orc.OrcFile;
import org.apache.orc.OrcProto;
import org.apache.orc.StripeInformation;
import org.apache.orc.StripeStatistics;

// TODO: Make OrcTail implement FileMetadata or Reader interface
public final class OrcTail {
  // postscript + footer - Serialized in OrcSplit
  private final OrcProto.FileTail fileTail;
  // serialized representation of metadata, footer and postscript
  private final ByteBuffer serializedTail;
  // used to invalidate cache entries
  private final long fileModificationTime;
  // lazily deserialized
  private OrcProto.Metadata metadata;

  public OrcTail(OrcProto.FileTail fileTail, ByteBuffer serializedTail) {
    this(fileTail, serializedTail, -1);
  }

  public OrcTail(OrcProto.FileTail fileTail, ByteBuffer serializedTail, long fileModificationTime) {
    this.fileTail = fileTail;
    this.serializedTail = serializedTail;
    this.fileModificationTime = fileModificationTime;
    this.metadata = null;
  }

  public ByteBuffer getSerializedTail() {
    return serializedTail;
  }

  public long getFileModificationTime() {
    return fileModificationTime;
  }

  public OrcProto.Footer getFooter() {
    return fileTail.getFooter();
  }

  public OrcProto.PostScript getPostScript() {
    return fileTail.getPostscript();
  }

  public OrcFile.WriterVersion getWriterVersion() {
    OrcProto.PostScript ps = fileTail.getPostscript();
    return (ps.hasWriterVersion()
        ? OrcFile.WriterVersion.from(ps.getWriterVersion()) : OrcFile.WriterVersion.ORIGINAL);
  }

  public List getStripes() {
    List result = new ArrayList<>(fileTail.getFooter().getStripesCount());
    for (OrcProto.StripeInformation stripeProto : fileTail.getFooter().getStripesList()) {
      result.add(new ReaderImpl.StripeInformationImpl(stripeProto));
    }
    return result;
  }

  public CompressionKind getCompressionKind() {
    return CompressionKind.valueOf(fileTail.getPostscript().getCompression().name());
  }

  public int getCompressionBufferSize() {
    return (int) fileTail.getPostscript().getCompressionBlockSize();
  }

  public List getStripeStatistics() throws IOException {
    List result = new ArrayList<>();
    List ssProto = getStripeStatisticsProto();
    if (ssProto != null) {
      for (OrcProto.StripeStatistics ss : ssProto) {
        result.add(new StripeStatistics(ss.getColStatsList()));
      }
    }
    return result;
  }

  public List getStripeStatisticsProto() throws IOException {
    if (serializedTail == null) return null;
    if (metadata == null) {
      CompressionCodec codec = OrcCodecPool.getCodec(getCompressionKind());
      try {
        metadata = extractMetadata(serializedTail, 0,
            (int) fileTail.getPostscript().getMetadataLength(), codec, getCompressionBufferSize());
      } finally {
        OrcCodecPool.returnCodec(getCompressionKind(), codec);
      }
      // clear does not clear the contents but sets position to 0 and limit = capacity
      serializedTail.clear();
    }
    return metadata.getStripeStatsList();
  }

  public int getMetadataSize() {
    return (int) getPostScript().getMetadataLength();
  }

  public List getTypes() {
    return getFooter().getTypesList();
  }

  public OrcProto.FileTail getFileTail() {
    return fileTail;
  }

  public OrcProto.FileTail getMinimalFileTail() {
    OrcProto.FileTail.Builder fileTailBuilder = OrcProto.FileTail.newBuilder(fileTail);
    OrcProto.Footer.Builder footerBuilder = OrcProto.Footer.newBuilder(fileTail.getFooter());
    footerBuilder.clearStatistics();
    fileTailBuilder.setFooter(footerBuilder.build());
    OrcProto.FileTail result = fileTailBuilder.build();
    return result;
  }
}