/**
    * 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.hbck;
  
  import java.io.FileNotFoundException;
  import java.io.IOException;
  import java.util.ArrayList;
  import java.util.Collection;
  import java.util.HashSet;
  import java.util.List;
  import java.util.Set;
  import java.util.concurrent.Callable;
  import java.util.concurrent.ConcurrentSkipListSet;
  import java.util.concurrent.ExecutionException;
  import java.util.concurrent.ExecutorService;
  import java.util.concurrent.Future;
  import java.util.concurrent.atomic.AtomicInteger;
  
  import org.apache.commons.logging.Log;
  import org.apache.commons.logging.LogFactory;
  import org.apache.hadoop.hbase.classification.InterfaceAudience;
  import org.apache.hadoop.conf.Configuration;
  import org.apache.hadoop.fs.FileStatus;
  import org.apache.hadoop.fs.FileSystem;
  import org.apache.hadoop.fs.Path;
  import org.apache.hadoop.hbase.HConstants;
  import org.apache.hadoop.hbase.io.hfile.CacheConfig;
  import org.apache.hadoop.hbase.io.hfile.CorruptHFileException;
  import org.apache.hadoop.hbase.io.hfile.HFile;
  import org.apache.hadoop.hbase.util.FSUtils;
  import org.apache.hadoop.hbase.util.FSUtils.FamilyDirFilter;
  import org.apache.hadoop.hbase.util.FSUtils.HFileFilter;
  import org.apache.hadoop.hbase.util.FSUtils.RegionDirFilter;
  import org.apache.hadoop.hbase.util.HBaseFsck.ErrorReporter;
  
  /**
   * This class marches through all of the region's hfiles and verifies that
   * they are all valid files. One just needs to instantiate the class, use
   * checkTables(List<Path>) and then retrieve the corrupted hfiles (and
   * quarantined files if in quarantining mode)
   *
   * The implementation currently parallelizes at the regionDir level.
   */
  @InterfaceAudience.Private
  public class HFileCorruptionChecker {
    private static final Log LOG = LogFactory.getLog(HFileCorruptionChecker.class);
  
    final Configuration conf;
    final FileSystem fs;
    final CacheConfig cacheConf;
    final ExecutorService executor;
    final Set<Path> corrupted = new ConcurrentSkipListSet<Path>();
    final Set<Path> failures = new ConcurrentSkipListSet<Path>();
    final Set<Path> quarantined = new ConcurrentSkipListSet<Path>();
    final Set<Path> missing = new ConcurrentSkipListSet<Path>();
    final boolean inQuarantineMode;
    final AtomicInteger hfilesChecked = new AtomicInteger();
  
    public HFileCorruptionChecker(Configuration conf, ExecutorService executor,
        boolean quarantine) throws IOException {
      this.conf = conf;
      this.fs = FileSystem.get(conf);
      this.cacheConf = new CacheConfig(conf);
      this.executor = executor;
      this.inQuarantineMode = quarantine;
    }
  
    /**
     * Checks a path to see if it is a valid hfile.
     *
     * @param p
     *          full Path to an HFile
     * @throws IOException
     *           This is a connectivity related exception
     */
    protected void checkHFile(Path p) throws IOException {
      HFile.Reader r = null;
      try {
        r = HFile.createReader(fs, p, cacheConf, conf);
      } catch (CorruptHFileException che) {
        LOG.warn("Found corrupt HFile " + p, che);
        corrupted.add(p);
        if (inQuarantineMode) {
          Path dest = createQuarantinePath(p);
         LOG.warn("Quarantining corrupt HFile " + p + " into " + dest);
         boolean success = fs.mkdirs(dest.getParent());
         success = success ? fs.rename(p, dest): false;
         if (!success) {
           failures.add(p);
         } else {
           quarantined.add(dest);
         }
       }
       return;
     } catch (FileNotFoundException fnfe) {
       LOG.warn("HFile " + p + " was missing.  Likely removed due to compaction/split?");
       missing.add(p);
     } finally {
       hfilesChecked.addAndGet(1);
       if (r != null) {
         r.close(true);
       }
     }
   }
 
   /**
    * Given a path, generates a new path to where we move a corrupted hfile (bad
    * trailer, no trailer).
    *
    * @param hFile
    *          Path to a corrupt hfile (assumes that it is HBASE_DIR/ table
    *          /region/cf/file)
    * @return path to where corrupted files are stored. This should be
    *         HBASE_DIR/.corrupt/table/region/cf/file.
    */
   Path createQuarantinePath(Path hFile) throws IOException {
     // extract the normal dirs structure
     Path cfDir = hFile.getParent();
     Path regionDir = cfDir.getParent();
     Path tableDir = regionDir.getParent();
 
     // build up the corrupted dirs strcture
     Path corruptBaseDir = new Path(FSUtils.getRootDir(conf), conf.get(
         "hbase.hfile.quarantine.dir", HConstants.CORRUPT_DIR_NAME));
     Path corruptTableDir = new Path(corruptBaseDir, tableDir.getName());
     Path corruptRegionDir = new Path(corruptTableDir, regionDir.getName());
     Path corruptFamilyDir = new Path(corruptRegionDir, cfDir.getName());
     Path corruptHfile = new Path(corruptFamilyDir, hFile.getName());
     return corruptHfile;
   }
 
   /**
    * Check all files in a column family dir.
    *
    * @param cfDir
    *          column family directory
    * @throws IOException
    */
   protected void checkColFamDir(Path cfDir) throws IOException {
     FileStatus[] hfs = null;
     try {
       hfs = fs.listStatus(cfDir, new HFileFilter(fs)); // use same filter as scanner.
     } catch (FileNotFoundException fnfe) {
       // Hadoop 0.23+ listStatus semantics throws an exception if the path does not exist.
       LOG.warn("Colfam Directory " + cfDir +
           " does not exist.  Likely due to concurrent split/compaction. Skipping.");
       missing.add(cfDir);
       return;
     }
 
     // Hadoop 1.0 listStatus does not throw an exception if the path does not exist.
     if (hfs.length == 0 && !fs.exists(cfDir)) {
       LOG.warn("Colfam Directory " + cfDir +
           " does not exist.  Likely due to concurrent split/compaction. Skipping.");
       missing.add(cfDir);
       return;
     }
     for (FileStatus hfFs : hfs) {
       Path hf = hfFs.getPath();
       checkHFile(hf);
     }
   }
 
   /**
    * Check all column families in a region dir.
    *
    * @param regionDir
    *          region directory
    * @throws IOException
    */
   protected void checkRegionDir(Path regionDir) throws IOException {
     FileStatus[] cfs = null;
     try {
       cfs = fs.listStatus(regionDir, new FamilyDirFilter(fs));
     } catch (FileNotFoundException fnfe) {
       // Hadoop 0.23+ listStatus semantics throws an exception if the path does not exist.
       LOG.warn("Region Directory " + regionDir +
           " does not exist.  Likely due to concurrent split/compaction. Skipping.");
       missing.add(regionDir);
       return;
     }
 
     // Hadoop 1.0 listStatus does not throw an exception if the path does not exist.
     if (cfs.length == 0 && !fs.exists(regionDir)) {
       LOG.warn("Region Directory " + regionDir +
           " does not exist.  Likely due to concurrent split/compaction. Skipping.");
       missing.add(regionDir);
       return;
     }
 
     for (FileStatus cfFs : cfs) {
       Path cfDir = cfFs.getPath();
       checkColFamDir(cfDir);
     }
   }
 
   /**
    * Check all the regiondirs in the specified tableDir
    *
    * @param tableDir
    *          path to a table
    * @throws IOException
    */
   void checkTableDir(Path tableDir) throws IOException {
     FileStatus[] rds = fs.listStatus(tableDir, new RegionDirFilter(fs));
     if (rds.length == 0 && !fs.exists(tableDir)) {
       // interestingly listStatus does not throw an exception if the path does not exist.
       LOG.warn("Table Directory " + tableDir +
           " does not exist.  Likely due to concurrent delete. Skipping.");
       missing.add(tableDir);
       return;
     }
 
     // Parallelize check at the region dir level
     List<RegionDirChecker> rdcs = new ArrayList<RegionDirChecker>();
     List<Future<Void>> rdFutures;
 
     for (FileStatus rdFs : rds) {
       Path rdDir = rdFs.getPath();
       RegionDirChecker work = new RegionDirChecker(rdDir);
       rdcs.add(work);
     }
 
     // Submit and wait for completion
     try {
       rdFutures = executor.invokeAll(rdcs);
     } catch (InterruptedException ie) {
       Thread.currentThread().interrupt();
       LOG.warn("Region dirs checking interrupted!", ie);
       return;
     }
 
     for (int i = 0; i < rdFutures.size(); i++) {
       Future<Void> f = rdFutures.get(i);
       try {
         f.get();
       } catch (ExecutionException e) {
         LOG.warn("Failed to quaratine an HFile in regiondir "
             + rdcs.get(i).regionDir, e.getCause());
         // rethrow IOExceptions
         if (e.getCause() instanceof IOException) {
           throw (IOException) e.getCause();
         }
 
         // rethrow RuntimeExceptions
         if (e.getCause() instanceof RuntimeException) {
           throw (RuntimeException) e.getCause();
         }
 
         // this should never happen
         LOG.error("Unexpected exception encountered", e);
         return; // bailing out.
       } catch (InterruptedException ie) {
         Thread.currentThread().interrupt();
         LOG.warn("Region dirs check interrupted!", ie);
         // bailing out
         return;
       }
     }
   }
 
   /**
    * An individual work item for parallelized regiondir processing. This is
    * intentionally an inner class so it can use the shared error sets and fs.
    */
   private class RegionDirChecker implements Callable<Void> {
     final Path regionDir;
 
     RegionDirChecker(Path regionDir) {
       this.regionDir = regionDir;
     }
 
     @Override
     public Void call() throws IOException {
       checkRegionDir(regionDir);
       return null;
     }
   }
 
   /**
    * Check the specified table dirs for bad hfiles.
    */
   public void checkTables(Collection<Path> tables) throws IOException {
     for (Path t : tables) {
       checkTableDir(t);
     }
   }
 
   /**
    * @return the set of check failure file paths after checkTables is called.
    */
   public Collection<Path> getFailures() {
     return new HashSet<Path>(failures);
   }
 
   /**
    * @return the set of corrupted file paths after checkTables is called.
    */
   public Collection<Path> getCorrupted() {
     return new HashSet<Path>(corrupted);
   }
 
   /**
    * @return number of hfiles checked in the last HfileCorruptionChecker run
    */
   public int getHFilesChecked() {
     return hfilesChecked.get();
   }
 
   /**
    * @return the set of successfully quarantined paths after checkTables is called.
    */
   public Collection<Path> getQuarantined() {
     return new HashSet<Path>(quarantined);
   }
 
   /**
    * @return the set of paths that were missing.  Likely due to deletion/moves from
    *  compaction or flushes.
    */
   public Collection<Path> getMissing() {
     return new HashSet<Path>(missing);
   }
 
   /**
    * Print a human readable summary of hfile quarantining operations.
    * @param out
    */
   public void report(ErrorReporter out) {
     out.print("Checked " + hfilesChecked.get() + " hfile for corruption");
     out.print("  HFiles corrupted:                  " + corrupted.size());
     if (inQuarantineMode) {
       out.print("    HFiles successfully quarantined: " + quarantined.size());
       for (Path sq : quarantined) {
         out.print("      " + sq);
       }
       out.print("    HFiles failed quarantine:        " + failures.size());
       for (Path fq : failures) {
         out.print("      " + fq);
       }
     }
     out.print("    HFiles moved while checking:     " + missing.size());
     for (Path mq : missing) {
       out.print("      " + mq);
     }
 
     String initialState = (corrupted.size() == 0) ? "OK" : "CORRUPTED";
     String fixedState = (corrupted.size() == quarantined.size()) ? "OK"
         : "CORRUPTED";
 
     if (inQuarantineMode) {
       out.print("Summary: " + initialState + " => " + fixedState);
     } else {
       out.print("Summary: " + initialState);
     }
   }
 }