com.uber.hoodie.common.table.log.block.HoodieDeleteBlock Maven / Gradle / Ivy

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/*
 * Copyright (c) 2016 Uber Technologies, Inc. ([email protected])
 *
 * 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.uber.hoodie.common.table.log.block;

import com.uber.hoodie.common.model.HoodieLogFile;
import com.uber.hoodie.common.storage.SizeAwareDataInputStream;
import com.uber.hoodie.exception.HoodieIOException;
import org.apache.commons.lang3.StringUtils;
import org.apache.hadoop.fs.FSDataInputStream;

import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.DataInputStream;
import java.io.DataOutputStream;
import java.io.IOException;
import java.nio.charset.Charset;
import java.util.HashMap;
import java.util.Map;
import java.util.Optional;

/**
 * Delete block contains a list of keys to be deleted from scanning the blocks so far
 */
public class HoodieDeleteBlock extends HoodieLogBlock {

  private String[] keysToDelete;

  public HoodieDeleteBlock(String[] keysToDelete,
      Map header) {
    this(Optional.empty(), null, false, Optional.empty(), header, new HashMap<>());
    this.keysToDelete = keysToDelete;
  }


  private HoodieDeleteBlock(Optional content, FSDataInputStream inputStream,
      boolean readBlockLazily, Optional blockContentLocation,
      Map header, Map footer) {
    super(header, footer, blockContentLocation, content, inputStream, readBlockLazily);
  }

  @Override
  public byte[] getContentBytes() throws IOException {

    // In case this method is called before realizing keys from content
    if (getContent().isPresent()) {
      return getContent().get();
    } else if (readBlockLazily && !getContent().isPresent() && keysToDelete == null) {
      // read block lazily
      getKeysToDelete();
    }

    ByteArrayOutputStream baos = new ByteArrayOutputStream();
    DataOutputStream output = new DataOutputStream(baos);
    byte[] bytesToWrite = StringUtils.join(getKeysToDelete(), ',').getBytes(Charset.forName("utf-8"));
    output.writeInt(HoodieLogBlock.version);
    output.writeInt(bytesToWrite.length);
    output.write(bytesToWrite);
    return baos.toByteArray();
  }

  public String[] getKeysToDelete() {
    try {
      if (keysToDelete == null) {
        if (!getContent().isPresent() && readBlockLazily) {
          // read content from disk
          inflate();
        }
        SizeAwareDataInputStream dis =
            new SizeAwareDataInputStream(new DataInputStream(new ByteArrayInputStream(getContent().get())));
        int version = dis.readInt();
        int dataLength = dis.readInt();
        byte[] data = new byte[dataLength];
        dis.readFully(data);
        this.keysToDelete = new String(data).split(",");
        deflate();
      }
      return keysToDelete;
    } catch (IOException io) {
      throw new HoodieIOException("Unable to generate keys to delete from block content", io);
    }
  }

  @Override
  public HoodieLogBlockType getBlockType() {
    return HoodieLogBlockType.DELETE_BLOCK;
  }

  public static HoodieLogBlock getBlock(HoodieLogFile logFile,
      FSDataInputStream inputStream,
      Optional content,
      boolean readBlockLazily,
      long position,
      long blockSize,
      long blockEndPos,
      Map header,
      Map footer) throws IOException {

    return new HoodieDeleteBlock(content, inputStream, readBlockLazily,
        Optional.of(new HoodieLogBlockContentLocation(logFile, position, blockSize, blockEndPos)), header, footer);
  }
}