/**
    *
    * 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.regionserver;
  
  import static org.junit.Assert.assertEquals;
  import static org.junit.Assert.assertFalse;
  import static org.junit.Assert.assertTrue;
  import static org.mockito.Matchers.anyInt;
  import static org.mockito.Matchers.eq;
  import static org.mockito.Mockito.*;
  
  import org.mockito.Mockito;
  
  import java.io.IOException;
  import java.util.ArrayList;
  import java.util.List;
  
  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.HBaseTestingUtility;
  import org.apache.hadoop.hbase.HColumnDescriptor;
  import org.apache.hadoop.hbase.HConstants;
  import org.apache.hadoop.hbase.HRegionInfo;
  import org.apache.hadoop.hbase.HTableDescriptor;
  import org.apache.hadoop.hbase.Server;
  import org.apache.hadoop.hbase.TableName;
  import org.apache.hadoop.hbase.client.Scan;
  import org.apache.hadoop.hbase.coprocessor.BaseRegionObserver;
  import org.apache.hadoop.hbase.coprocessor.CoprocessorHost;
  import org.apache.hadoop.hbase.coprocessor.ObserverContext;
  import org.apache.hadoop.hbase.coprocessor.RegionCoprocessorEnvironment;
  import org.apache.hadoop.hbase.io.hfile.CacheConfig;
  import org.apache.hadoop.hbase.io.hfile.LruBlockCache;
  import org.apache.hadoop.hbase.testclassification.SmallTests;
  import org.apache.hadoop.hbase.util.Bytes;
  import org.apache.hadoop.hbase.util.FSUtils;
  import org.apache.hadoop.hbase.util.PairOfSameType;
  import org.apache.hadoop.hbase.wal.WALFactory;
  import org.apache.zookeeper.KeeperException;
  import org.junit.After;
  import org.junit.Before;
  import org.junit.Test;
  import org.junit.experimental.categories.Category;
  
  import com.google.common.collect.ImmutableList;
  
  /**
   * Test the {@link SplitTransactionImpl} class against an HRegion (as opposed to
   * running cluster).
   */
  @Category(SmallTests.class)
  public class TestSplitTransaction {
    private final HBaseTestingUtility TEST_UTIL = new HBaseTestingUtility();
    private final Path testdir =
      TEST_UTIL.getDataTestDir(this.getClass().getName());
    private HRegion parent;
    private WALFactory wals;
    private FileSystem fs;
    private static final byte [] STARTROW = new byte [] {'a', 'a', 'a'};
    // '{' is next ascii after 'z'.
    private static final byte [] ENDROW = new byte [] {'{', '{', '{'};
    private static final byte [] GOOD_SPLIT_ROW = new byte [] {'d', 'd', 'd'};
    private static final byte [] CF = HConstants.CATALOG_FAMILY;
    
    private static boolean preRollBackCalled = false;
    private static boolean postRollBackCalled = false;
    
    @Before public void setup() throws IOException {
      this.fs = FileSystem.get(TEST_UTIL.getConfiguration());
      TEST_UTIL.getConfiguration().set(CoprocessorHost.REGION_COPROCESSOR_CONF_KEY, CustomObserver.class.getName());
      this.fs.delete(this.testdir, true);
      final Configuration walConf = new Configuration(TEST_UTIL.getConfiguration());
      FSUtils.setRootDir(walConf, this.testdir);
      this.wals = new WALFactory(walConf, null, this.getClass().getName());
      
      this.parent = createRegion(this.testdir, this.wals);
      RegionCoprocessorHost host = new RegionCoprocessorHost(this.parent, null, TEST_UTIL.getConfiguration());
      this.parent.setCoprocessorHost(host);
      TEST_UTIL.getConfiguration().setBoolean("hbase.testing.nocluster", true);
    }
  
   @After public void teardown() throws IOException {
     if (this.parent != null && !this.parent.isClosed()) this.parent.close();
     Path regionDir = this.parent.getRegionFileSystem().getRegionDir();
     if (this.fs.exists(regionDir) && !this.fs.delete(regionDir, true)) {
       throw new IOException("Failed delete of " + regionDir);
     }
     if (this.wals != null) {
       this.wals.close();
     }
     this.fs.delete(this.testdir, true);
   }
 
   @Test public void testFailAfterPONR() throws IOException, KeeperException {
     final int rowcount = TEST_UTIL.loadRegion(this.parent, CF);
     assertTrue(rowcount > 0);
     int parentRowCount = countRows(this.parent);
     assertEquals(rowcount, parentRowCount);
 
     // Start transaction.
     SplitTransactionImpl st = prepareGOOD_SPLIT_ROW();
     SplitTransactionImpl spiedUponSt = spy(st);
     Mockito
         .doThrow(new MockedFailedDaughterOpen())
         .when(spiedUponSt)
         .openDaughterRegion((Server) Mockito.anyObject(),
             (HRegion) Mockito.anyObject());
 
     // Run the execute.  Look at what it returns.
     boolean expectedException = false;
     Server mockServer = Mockito.mock(Server.class);
     when(mockServer.getConfiguration()).thenReturn(TEST_UTIL.getConfiguration());
     try {
       spiedUponSt.execute(mockServer, null);
     } catch (IOException e) {
       if (e.getCause() != null &&
           e.getCause() instanceof MockedFailedDaughterOpen) {
         expectedException = true;
       }
     }
     assertTrue(expectedException);
     // Run rollback returns that we should restart.
     assertFalse(spiedUponSt.rollback(null, null));
     // Make sure that region a and region b are still in the filesystem, that
     // they have not been removed; this is supposed to be the case if we go
     // past point of no return.
     Path tableDir =  this.parent.getRegionFileSystem().getTableDir();
     Path daughterADir = new Path(tableDir, spiedUponSt.getFirstDaughter().getEncodedName());
     Path daughterBDir = new Path(tableDir, spiedUponSt.getSecondDaughter().getEncodedName());
     assertTrue(TEST_UTIL.getTestFileSystem().exists(daughterADir));
     assertTrue(TEST_UTIL.getTestFileSystem().exists(daughterBDir));
   }
 
   /**
    * Test straight prepare works.  Tries to split on {@link #GOOD_SPLIT_ROW}
    * @throws IOException
    */
   @Test public void testPrepare() throws IOException {
     prepareGOOD_SPLIT_ROW();
   }
 
   private SplitTransactionImpl prepareGOOD_SPLIT_ROW() throws IOException {
     return prepareGOOD_SPLIT_ROW(this.parent);
   }
 
   private SplitTransactionImpl prepareGOOD_SPLIT_ROW(final HRegion parentRegion)
       throws IOException {
     SplitTransactionImpl st = new SplitTransactionImpl(parentRegion, GOOD_SPLIT_ROW);
     assertTrue(st.prepare());
     return st;
   }
 
   /**
    * Pass a reference store
    */
   @Test public void testPrepareWithRegionsWithReference() throws IOException {
     HStore storeMock = Mockito.mock(HStore.class);
     when(storeMock.hasReferences()).thenReturn(true);
     when(storeMock.getFamily()).thenReturn(new HColumnDescriptor("cf"));
     when(storeMock.close()).thenReturn(ImmutableList.<StoreFile>of());
     this.parent.stores.put(Bytes.toBytes(""), storeMock);
 
     SplitTransactionImpl st = new SplitTransactionImpl(this.parent, GOOD_SPLIT_ROW);
 
     assertFalse("a region should not be splittable if it has instances of store file references",
                 st.prepare());
   }
 
   /**
    * Test SplitTransactionListener
    */
   @Test public void testSplitTransactionListener() throws IOException {
     SplitTransactionImpl st = new SplitTransactionImpl(this.parent, GOOD_SPLIT_ROW);
     SplitTransaction.TransactionListener listener =
             Mockito.mock(SplitTransaction.TransactionListener.class);
     st.registerTransactionListener(listener);
     st.prepare();
     Server mockServer = Mockito.mock(Server.class);
     when(mockServer.getConfiguration()).thenReturn(TEST_UTIL.getConfiguration());
     PairOfSameType<Region> daughters = st.execute(mockServer, null);
     verify(listener).transition(st, SplitTransaction.SplitTransactionPhase.STARTED,
             SplitTransaction.SplitTransactionPhase.PREPARED);
     verify(listener, times(15)).transition(any(SplitTransaction.class),
             any(SplitTransaction.SplitTransactionPhase.class),
             any(SplitTransaction.SplitTransactionPhase.class));
     verifyNoMoreInteractions(listener);
   }
 
   /**
    * Pass an unreasonable split row.
    */
   @Test public void testPrepareWithBadSplitRow() throws IOException {
     // Pass start row as split key.
     SplitTransactionImpl st = new SplitTransactionImpl(this.parent, STARTROW);
     assertFalse(st.prepare());
     st = new SplitTransactionImpl(this.parent, HConstants.EMPTY_BYTE_ARRAY);
     assertFalse(st.prepare());
     st = new SplitTransactionImpl(this.parent, new byte [] {'A', 'A', 'A'});
     assertFalse(st.prepare());
     st = new SplitTransactionImpl(this.parent, ENDROW);
     assertFalse(st.prepare());
   }
 
   @Test public void testPrepareWithClosedRegion() throws IOException {
     this.parent.close();
     SplitTransactionImpl st = new SplitTransactionImpl(this.parent, GOOD_SPLIT_ROW);
     assertFalse(st.prepare());
   }
 
   @Test public void testWholesomeSplit() throws IOException {
     final int rowcount = TEST_UTIL.loadRegion(this.parent, CF, true);
     assertTrue(rowcount > 0);
     int parentRowCount = countRows(this.parent);
     assertEquals(rowcount, parentRowCount);
 
     // Pretend region's blocks are not in the cache, used for
     // testWholesomeSplitWithHFileV1
     CacheConfig cacheConf = new CacheConfig(TEST_UTIL.getConfiguration());
     ((LruBlockCache) cacheConf.getBlockCache()).clearCache();
 
     // Start transaction.
     SplitTransactionImpl st = prepareGOOD_SPLIT_ROW();
 
     // Run the execute.  Look at what it returns.
     Server mockServer = Mockito.mock(Server.class);
     when(mockServer.getConfiguration()).thenReturn(TEST_UTIL.getConfiguration());
     PairOfSameType<Region> daughters = st.execute(mockServer, null);
     // Do some assertions about execution.
     assertTrue(this.fs.exists(this.parent.getRegionFileSystem().getSplitsDir()));
     // Assert the parent region is closed.
     assertTrue(this.parent.isClosed());
 
     // Assert splitdir is empty -- because its content will have been moved out
     // to be under the daughter region dirs.
     assertEquals(0, this.fs.listStatus(this.parent.getRegionFileSystem().getSplitsDir()).length);
     // Check daughters have correct key span.
     assertTrue(Bytes.equals(parent.getRegionInfo().getStartKey(),
       daughters.getFirst().getRegionInfo().getStartKey()));
     assertTrue(Bytes.equals(GOOD_SPLIT_ROW, daughters.getFirst().getRegionInfo().getEndKey()));
     assertTrue(Bytes.equals(daughters.getSecond().getRegionInfo().getStartKey(), GOOD_SPLIT_ROW));
     assertTrue(Bytes.equals(parent.getRegionInfo().getEndKey(),
       daughters.getSecond().getRegionInfo().getEndKey()));
     // Count rows. daughters are already open
     int daughtersRowCount = 0;
     for (Region openRegion: daughters) {
       try {
         int count = countRows(openRegion);
         assertTrue(count > 0 && count != rowcount);
         daughtersRowCount += count;
       } finally {
         HRegion.closeHRegion((HRegion)openRegion);
       }
     }
     assertEquals(rowcount, daughtersRowCount);
     // Assert the write lock is no longer held on parent
     assertTrue(!this.parent.lock.writeLock().isHeldByCurrentThread());
   }
 
   @Test
   public void testCountReferencesFailsSplit() throws IOException {
     final int rowcount = TEST_UTIL.loadRegion(this.parent, CF);
     assertTrue(rowcount > 0);
     int parentRowCount = countRows(this.parent);
     assertEquals(rowcount, parentRowCount);
 
     // Start transaction.
     HRegion spiedRegion = spy(this.parent);
     SplitTransactionImpl st = prepareGOOD_SPLIT_ROW(spiedRegion);
     SplitTransactionImpl spiedUponSt = spy(st);
     doThrow(new IOException("Failing split. Expected reference file count isn't equal."))
         .when(spiedUponSt).assertReferenceFileCount(anyInt(),
         eq(new Path(this.parent.getRegionFileSystem().getTableDir(),
             st.getSecondDaughter().getEncodedName())));
 
     // Run the execute.  Look at what it returns.
     boolean expectedException = false;
     Server mockServer = Mockito.mock(Server.class);
     when(mockServer.getConfiguration()).thenReturn(TEST_UTIL.getConfiguration());
     try {
       spiedUponSt.execute(mockServer, null);
     } catch (IOException e) {
       expectedException = true;
     }
     assertTrue(expectedException);
   }
 
 
   @Test public void testRollback() throws IOException {
     final int rowcount = TEST_UTIL.loadRegion(this.parent, CF);
     assertTrue(rowcount > 0);
     int parentRowCount = countRows(this.parent);
     assertEquals(rowcount, parentRowCount);
 
     // Start transaction.
     HRegion spiedRegion = spy(this.parent);
     SplitTransactionImpl st = prepareGOOD_SPLIT_ROW(spiedRegion);
     SplitTransactionImpl spiedUponSt = spy(st);
     doNothing().when(spiedUponSt).assertReferenceFileCount(anyInt(),
         eq(parent.getRegionFileSystem().getSplitsDir(st.getFirstDaughter())));
     when(spiedRegion.createDaughterRegionFromSplits(spiedUponSt.getSecondDaughter())).
         thenThrow(new MockedFailedDaughterCreation());
     // Run the execute.  Look at what it returns.
     boolean expectedException = false;
     Server mockServer = Mockito.mock(Server.class);
     when(mockServer.getConfiguration()).thenReturn(TEST_UTIL.getConfiguration());
     try {
       spiedUponSt.execute(mockServer, null);
     } catch (MockedFailedDaughterCreation e) {
       expectedException = true;
     }
     assertTrue(expectedException);
     // Run rollback
     assertTrue(spiedUponSt.rollback(null, null));
 
     // Assert I can scan parent.
     int parentRowCount2 = countRows(this.parent);
     assertEquals(parentRowCount, parentRowCount2);
 
     // Assert rollback cleaned up stuff in fs
     assertTrue(!this.fs.exists(HRegion.getRegionDir(this.testdir, st.getFirstDaughter())));
     assertTrue(!this.fs.exists(HRegion.getRegionDir(this.testdir, st.getSecondDaughter())));
     assertTrue(!this.parent.lock.writeLock().isHeldByCurrentThread());
 
     // Now retry the split but do not throw an exception this time.
     assertTrue(st.prepare());
     PairOfSameType<Region> daughters = st.execute(mockServer, null);
     // Count rows. daughters are already open
     int daughtersRowCount = 0;
     for (Region openRegion: daughters) {
       try {
         int count = countRows(openRegion);
         assertTrue(count > 0 && count != rowcount);
         daughtersRowCount += count;
       } finally {
         HRegion.closeHRegion((HRegion)openRegion);
       }
     }
     assertEquals(rowcount, daughtersRowCount);
     // Assert the write lock is no longer held on parent
     assertTrue(!this.parent.lock.writeLock().isHeldByCurrentThread());
     assertTrue("Rollback hooks should be called.", wasRollBackHookCalled());
   }
   
   private boolean wasRollBackHookCalled(){
     return (preRollBackCalled && postRollBackCalled);
   }
 
   /**
    * Exception used in this class only.
    */
   @SuppressWarnings("serial")
   private class MockedFailedDaughterCreation extends IOException {}
   private class MockedFailedDaughterOpen extends IOException {}
 
   private int countRows(final Region r) throws IOException {
     int rowcount = 0;
     InternalScanner scanner = r.getScanner(new Scan());
     try {
       List<Cell> kvs = new ArrayList<Cell>();
       boolean hasNext = true;
       while (hasNext) {
         hasNext = scanner.next(kvs);
         if (!kvs.isEmpty()) rowcount++;
       }
     } finally {
       scanner.close();
     }
     return rowcount;
   }
 
   HRegion createRegion(final Path testdir, final WALFactory wals)
   throws IOException {
     // Make a region with start and end keys. Use 'aaa', to 'AAA'.  The load
     // region utility will add rows between 'aaa' and 'zzz'.
     HTableDescriptor htd = new HTableDescriptor(TableName.valueOf("table"));
     HColumnDescriptor hcd = new HColumnDescriptor(CF);
     htd.addFamily(hcd);
     HRegionInfo hri = new HRegionInfo(htd.getTableName(), STARTROW, ENDROW);
     HRegion r = HRegion.createHRegion(hri, testdir, TEST_UTIL.getConfiguration(), htd);
     HRegion.closeHRegion(r);
     return HRegion.openHRegion(testdir, hri, htd,
       wals.getWAL(hri.getEncodedNameAsBytes(), hri.getTable().getNamespace()),
       TEST_UTIL.getConfiguration());
   }
   
   public static class CustomObserver extends BaseRegionObserver{
     @Override
     public void preRollBackSplit(
         ObserverContext<RegionCoprocessorEnvironment> ctx) throws IOException {
       preRollBackCalled = true;
     }
     
     @Override
     public void postRollBackSplit(
         ObserverContext<RegionCoprocessorEnvironment> ctx) throws IOException {
       postRollBackCalled = true;
     }
   }
 
 }