/**
    *
    * 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.hadoop.hbase.util;
  
  import java.io.IOException;
  
  import org.apache.commons.lang.StringUtils;
  import org.apache.commons.logging.Log;
  import org.apache.commons.logging.LogFactory;
  import org.apache.hadoop.hbase.classification.InterfaceAudience;
  import org.apache.hadoop.hbase.classification.InterfaceStability;
  import org.apache.hadoop.conf.Configuration;
  import org.apache.hadoop.fs.FileSystem;
  import org.apache.hadoop.fs.Path;
  import org.apache.hadoop.hbase.Cell;
  import org.apache.hadoop.hbase.CellComparator;
  import org.apache.hadoop.hbase.CellUtil;
  import org.apache.hadoop.hbase.DoNotRetryIOException;
  import org.apache.hadoop.hbase.HBaseConfiguration;
  import org.apache.hadoop.hbase.HBaseInterfaceAudience;
  import org.apache.hadoop.hbase.io.compress.Compression;
  import org.apache.hadoop.hbase.io.hfile.AbstractHFileWriter;
  import org.apache.hadoop.hbase.io.hfile.CacheConfig;
  import org.apache.hadoop.hbase.io.hfile.HFile;
  import org.apache.hadoop.hbase.io.hfile.HFileContext;
  import org.apache.hadoop.hbase.io.hfile.HFileContextBuilder;
  import org.apache.hadoop.hbase.io.hfile.HFileScanner;
  import org.apache.hadoop.io.compress.Compressor;
  
  /**
   * Compression validation test.  Checks compression is working.  Be sure to run
   * on every node in your cluster.
   */
  @InterfaceAudience.LimitedPrivate(HBaseInterfaceAudience.TOOLS)
  @InterfaceStability.Evolving
  public class CompressionTest {
    private static final Log LOG = LogFactory.getLog(CompressionTest.class);
  
    public static boolean testCompression(String codec) {
      codec = codec.toLowerCase();
  
      Compression.Algorithm a;
  
      try {
        a = Compression.getCompressionAlgorithmByName(codec);
      } catch (IllegalArgumentException e) {
        LOG.warn("Codec type: " + codec + " is not known");
        return false;
      }
  
      try {
        testCompression(a);
        return true;
      } catch (IOException ignored) {
        LOG.warn("Can't instantiate codec: " + codec, ignored);
        return false;
      }
    }
  
    private final static Boolean[] compressionTestResults
        = new Boolean[Compression.Algorithm.values().length];
    static {
      for (int i = 0 ; i < compressionTestResults.length ; ++i) {
        compressionTestResults[i] = null;
      }
    }
  
    public static void testCompression(Compression.Algorithm algo)
        throws IOException {
      if (compressionTestResults[algo.ordinal()] != null) {
        if (compressionTestResults[algo.ordinal()]) {
          return ; // already passed test, dont do it again.
        } else {
          // failed.
          throw new DoNotRetryIOException("Compression algorithm '" + algo.getName() + "'" +
          " previously failed test.");
        }
      }
  
      try {
        Compressor c = algo.getCompressor();
        algo.returnCompressor(c);
        compressionTestResults[algo.ordinal()] = true; // passes
     } catch (Throwable t) {
       compressionTestResults[algo.ordinal()] = false; // failure
       throw new DoNotRetryIOException(t);
     }
   }
 
   protected static Path path = new Path(".hfile-comp-test");
 
   public static void usage() {
 
     System.err.println(
       "Usage: CompressionTest <path> " +
       StringUtils.join( Compression.Algorithm.values(), "|").toLowerCase() +
       "\n" +
       "For example:\n" +
       "  hbase " + CompressionTest.class + " file:///tmp/testfile gz\n");
     System.exit(1);
   }
 
   public static void doSmokeTest(FileSystem fs, Path path, String codec)
   throws Exception {
     Configuration conf = HBaseConfiguration.create();
     HFileContext context = new HFileContextBuilder()
                            .withCompression(AbstractHFileWriter.compressionByName(codec)).build();
     HFile.Writer writer = HFile.getWriterFactoryNoCache(conf)
         .withPath(fs, path)
         .withFileContext(context)
         .create();
     // Write any-old Cell...
     final byte [] rowKey = Bytes.toBytes("compressiontestkey");
     Cell c = CellUtil.createCell(rowKey, Bytes.toBytes("compressiontestval"));
     writer.append(c);
     writer.appendFileInfo(Bytes.toBytes("compressioninfokey"), Bytes.toBytes("compressioninfoval"));
     writer.close();
     Cell cc = null;
     HFile.Reader reader = HFile.createReader(fs, path, new CacheConfig(conf), conf);
     try {
       reader.loadFileInfo();
       HFileScanner scanner = reader.getScanner(false, true);
       scanner.seekTo(); // position to the start of file
       // Scanner does not do Cells yet. Do below for now till fixed.
       cc = scanner.getKeyValue();
       if (CellComparator.compareRows(c, cc) != 0) {
         throw new Exception("Read back incorrect result: " + c.toString() + " vs " + cc.toString());
       }
     } finally {
       reader.close();
     }
   }
 
   public static void main(String[] args) throws Exception {
     if (args.length != 2) {
       usage();
       System.exit(1);
     }
 
     Configuration conf = new Configuration();
     Path path = new Path(args[0]);
     FileSystem fs = path.getFileSystem(conf);
     try {
       doSmokeTest(fs, path, args[1]);
     } finally {
       fs.delete(path, false);
     }
     System.out.println("SUCCESS");
   }
 }