/*
    * 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.io.hfile;
  
  import static org.junit.Assert.*;
  
  import java.io.IOException;
  import java.util.Random;
  
  import org.apache.hadoop.conf.Configuration;
  import org.apache.hadoop.fs.FileSystem;
  import org.apache.hadoop.fs.Path;
  import org.apache.hadoop.hbase.HBaseTestingUtility;
  import org.apache.hadoop.hbase.HBaseConfiguration;
  import org.apache.hadoop.hbase.HColumnDescriptor;
  import org.apache.hadoop.hbase.util.Bytes;
  import org.apache.hadoop.hbase.KeyValue;
  import org.apache.hadoop.hbase.testclassification.SmallTests;
  import org.apache.hadoop.hbase.fs.HFileSystem;
  import org.apache.hadoop.hbase.regionserver.StoreFile;
  
  import org.junit.Before;
  import org.junit.Test;
  import org.junit.experimental.categories.Category;
  
  @Category(SmallTests.class)
  public class TestPrefetch {
  
    private static final HBaseTestingUtility TEST_UTIL = new HBaseTestingUtility();
  
    private static final int NUM_VALID_KEY_TYPES = KeyValue.Type.values().length - 2;
    private static final int DATA_BLOCK_SIZE = 2048;
    private static final int NUM_KV = 1000;
    private static final Random RNG = new Random();
  
    private Configuration conf;
    private CacheConfig cacheConf;
    private FileSystem fs;
  
    @Before
    public void setUp() throws IOException {
      conf = TEST_UTIL.getConfiguration();
      conf.setInt(HFile.FORMAT_VERSION_KEY, 3);
      conf.setBoolean(CacheConfig.PREFETCH_BLOCKS_ON_OPEN_KEY, true);
      fs = HFileSystem.get(conf);
      CacheConfig.blockCacheDisabled = false;
      cacheConf = new CacheConfig(conf);
    }
  
    @Test
    public void testPrefetchSetInHCDWorks() {
      HColumnDescriptor hcd = new HColumnDescriptor(Bytes.toBytes("f"));
      hcd.setPrefetchBlocksOnOpen(true);
      Configuration c = HBaseConfiguration.create();
      assertFalse(c.getBoolean(CacheConfig.PREFETCH_BLOCKS_ON_OPEN_KEY, false));
      CacheConfig cc = new CacheConfig(c, hcd);
      assertTrue(cc.shouldPrefetchOnOpen());
    }
  
    @Test(timeout=60000)
    public void testPrefetch() throws Exception {
      Path storeFile = writeStoreFile();
      readStoreFile(storeFile);
    }
  
    private void readStoreFile(Path storeFilePath) throws Exception {
      // Open the file
      HFileReaderV2 reader = (HFileReaderV2) HFile.createReader(fs,
        storeFilePath, cacheConf, conf);
  
      while (!((HFileReaderV3)reader).prefetchComplete()) {
        // Sleep for a bit
        Thread.sleep(1000);
      }
  
      // Check that all of the data blocks were preloaded
      BlockCache blockCache = cacheConf.getBlockCache();
      long offset = 0;
      while (offset < reader.getTrailer().getLoadOnOpenDataOffset()) {
        HFileBlock block = reader.readBlock(offset, -1, false, true, false, true, null, null);
        BlockCacheKey blockCacheKey = new BlockCacheKey(reader.getName(), offset);
        boolean isCached = blockCache.getBlock(blockCacheKey, true, false, true) != null;
        if (block.getBlockType() == BlockType.DATA ||
            block.getBlockType() == BlockType.ROOT_INDEX ||
           block.getBlockType() == BlockType.INTERMEDIATE_INDEX) {
         assertTrue(isCached);
       }
       offset += block.getOnDiskSizeWithHeader();
     }
   }
 
   private Path writeStoreFile() throws IOException {
     Path storeFileParentDir = new Path(TEST_UTIL.getDataTestDir(), "TestPrefetch");
     HFileContext meta = new HFileContextBuilder()
       .withBlockSize(DATA_BLOCK_SIZE)
       .build();
     StoreFile.Writer sfw = new StoreFile.WriterBuilder(conf, cacheConf, fs)
       .withOutputDir(storeFileParentDir)
       .withComparator(KeyValue.COMPARATOR)
       .withFileContext(meta)
       .build();
 
     final int rowLen = 32;
     for (int i = 0; i < NUM_KV; ++i) {
       byte[] k = TestHFileWriterV2.randomOrderedKey(RNG, i);
       byte[] v = TestHFileWriterV2.randomValue(RNG);
       int cfLen = RNG.nextInt(k.length - rowLen + 1);
       KeyValue kv = new KeyValue(
           k, 0, rowLen,
           k, rowLen, cfLen,
           k, rowLen + cfLen, k.length - rowLen - cfLen,
           RNG.nextLong(),
           generateKeyType(RNG),
           v, 0, v.length);
       sfw.append(kv);
     }
 
     sfw.close();
     return sfw.getPath();
   }
 
   public static KeyValue.Type generateKeyType(Random rand) {
     if (rand.nextBoolean()) {
       // Let's make half of KVs puts.
       return KeyValue.Type.Put;
     } else {
       KeyValue.Type keyType =
           KeyValue.Type.values()[1 + rand.nextInt(NUM_VALID_KEY_TYPES)];
       if (keyType == KeyValue.Type.Minimum || keyType == KeyValue.Type.Maximum)
       {
         throw new RuntimeException("Generated an invalid key type: " + keyType
             + ". " + "Probably the layout of KeyValue.Type has changed.");
       }
       return keyType;
     }
   }
 
 }