content: /**
   * 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.activemq.store.kahadb.plist;
  
  import org.apache.activemq.broker.BrokerService;
  import org.apache.activemq.broker.BrokerServiceAware;
  import org.apache.activemq.store.JournaledStore;
  import org.apache.activemq.store.PList;
  import org.apache.activemq.store.PListStore;
  import org.apache.activemq.store.kahadb.disk.index.BTreeIndex;
  import org.apache.activemq.store.kahadb.disk.journal.Journal;
  import org.apache.activemq.store.kahadb.disk.journal.Location;
  import org.apache.activemq.store.kahadb.disk.page.Page;
  import org.apache.activemq.store.kahadb.disk.page.PageFile;
  import org.apache.activemq.store.kahadb.disk.page.Transaction;
  import org.apache.activemq.store.kahadb.disk.util.StringMarshaller;
  import org.apache.activemq.store.kahadb.disk.util.VariableMarshaller;
  import org.apache.activemq.thread.Scheduler;
  import org.apache.activemq.util.*;
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  import java.io.DataInput;
  import java.io.DataOutput;
  import java.io.File;
  import java.io.IOException;
  import java.util.*;
  import java.util.Map.Entry;
  
  /**
   * @org.apache.xbean.XBean
   */
  public class PListStoreImpl extends ServiceSupport implements BrokerServiceAware, Runnable, PListStore, JournaledStore {
      static final Logger LOG = LoggerFactory.getLogger(PListStoreImpl.class);
      private static final int DATABASE_LOCKED_WAIT_DELAY = 10 * 1000;
  
      static final int CLOSED_STATE = 1;
      static final int OPEN_STATE = 2;
  
      private File directory;
      private File indexDirectory;
      PageFile pageFile;
      private Journal journal;
      private LockFile lockFile;
      private boolean failIfDatabaseIsLocked;
      private int journalMaxFileLength = Journal.DEFAULT_MAX_FILE_LENGTH;
      private int journalMaxWriteBatchSize = Journal.DEFAULT_MAX_WRITE_BATCH_SIZE;
      private boolean enableIndexWriteAsync = false;
      private boolean initialized = false;
      private boolean lazyInit = true;
      // private int indexWriteBatchSize = PageFile.DEFAULT_WRITE_BATCH_SIZE;
      MetaData metaData = new MetaData(this);
      final MetaDataMarshaller metaDataMarshaller = new MetaDataMarshaller(this);
      Map<String, PListImpl> persistentLists = new HashMap<String, PListImpl>();
      final Object indexLock = new Object();
      private Scheduler scheduler;
      private long cleanupInterval = 30000;
  
      private int indexPageSize = PageFile.DEFAULT_PAGE_SIZE;
      private int indexCacheSize = PageFile.DEFAULT_PAGE_CACHE_SIZE;
      private int indexWriteBatchSize = PageFile.DEFAULT_WRITE_BATCH_SIZE;
      private boolean indexEnablePageCaching = true;
  
      public Object getIndexLock() {
          return indexLock;
      }
  
      @Override
      public void setBrokerService(BrokerService brokerService) {
          this.scheduler = brokerService.getScheduler();
      }
  
      public int getIndexPageSize() {
          return indexPageSize;
      }
  
      public int getIndexCacheSize() {
          return indexCacheSize;
      }
  
      public int getIndexWriteBatchSize() {
          return indexWriteBatchSize;
      }
  
      public void setIndexPageSize(int indexPageSize) {
          this.indexPageSize = indexPageSize;
      }
  
      public void setIndexCacheSize(int indexCacheSize) {
          this.indexCacheSize = indexCacheSize;
      }
  
      public void setIndexWriteBatchSize(int indexWriteBatchSize) {
          this.indexWriteBatchSize = indexWriteBatchSize;
      }
  
      public boolean getIndexEnablePageCaching() {
          return indexEnablePageCaching;
      }
  
      public void setIndexEnablePageCaching(boolean indexEnablePageCaching) {
          this.indexEnablePageCaching = indexEnablePageCaching;
      }
  
      protected class MetaData {
          protected MetaData(PListStoreImpl store) {
              this.store = store;
          }
  
          private final PListStoreImpl store;
          Page<MetaData> page;
          BTreeIndex<String, PListImpl> lists;
  
          void createIndexes(Transaction tx) throws IOException {
              this.lists = new BTreeIndex<String, PListImpl>(pageFile, tx.allocate().getPageId());
          }
  
          void load(Transaction tx) throws IOException {
              this.lists.setKeyMarshaller(StringMarshaller.INSTANCE);
              this.lists.setValueMarshaller(new PListMarshaller(this.store));
              this.lists.load(tx);
          }
  
          void loadLists(Transaction tx, Map<String, PListImpl> lists) throws IOException {
              for (Iterator<Entry<String, PListImpl>> i = this.lists.iterator(tx); i.hasNext();) {
                  Entry<String, PListImpl> entry = i.next();
                  entry.getValue().load(tx);
                  lists.put(entry.getKey(), entry.getValue());
              }
          }
  
          public void read(DataInput is) throws IOException {
              this.lists = new BTreeIndex<String, PListImpl>(pageFile, is.readLong());
              this.lists.setKeyMarshaller(StringMarshaller.INSTANCE);
              this.lists.setValueMarshaller(new PListMarshaller(this.store));
          }
  
          public void write(DataOutput os) throws IOException {
              os.writeLong(this.lists.getPageId());
          }
      }
  
      class MetaDataMarshaller extends VariableMarshaller<MetaData> {
          private final PListStoreImpl store;
  
          MetaDataMarshaller(PListStoreImpl store) {
              this.store = store;
          }
          @Override
          public MetaData readPayload(DataInput dataIn) throws IOException {
              MetaData rc = new MetaData(this.store);
              rc.read(dataIn);
              return rc;
          }
  
          @Override
          public void writePayload(MetaData object, DataOutput dataOut) throws IOException {
              object.write(dataOut);
          }
      }
  
      class PListMarshaller extends VariableMarshaller<PListImpl> {
          private final PListStoreImpl store;
          PListMarshaller(PListStoreImpl store) {
              this.store = store;
          }
          @Override
          public PListImpl readPayload(DataInput dataIn) throws IOException {
              PListImpl result = new PListImpl(this.store);
              result.read(dataIn);
              return result;
          }
  
          @Override
          public void writePayload(PListImpl list, DataOutput dataOut) throws IOException {
              list.write(dataOut);
          }
      }
  
      public Journal getJournal() {
          return this.journal;
      }
  
      @Override
      public File getDirectory() {
          return directory;
      }
  
      @Override
      public void setDirectory(File directory) {
          this.directory = directory;
      }
  
      public File getIndexDirectory() {
          return indexDirectory != null ? indexDirectory : directory;
      }
  
      public void setIndexDirectory(File indexDirectory) {
          this.indexDirectory = indexDirectory;
      }
  
      @Override
      public long size() {
          synchronized (this) {
              if (!initialized) {
                  return 0;
              }
          }
          try {
              return journal.getDiskSize() + pageFile.getDiskSize();
          } catch (IOException e) {
              throw new RuntimeException(e);
          }
      }
  
      @Override
      public PListImpl getPList(final String name) throws Exception {
          if (!isStarted()) {
              throw new IllegalStateException("Not started");
          }
          intialize();
          synchronized (indexLock) {
              synchronized (this) {
                  PListImpl result = this.persistentLists.get(name);
                  if (result == null) {
                      final PListImpl pl = new PListImpl(this);
                      pl.setName(name);
                      getPageFile().tx().execute(new Transaction.Closure<IOException>() {
                          @Override
                          public void execute(Transaction tx) throws IOException {
                              pl.setHeadPageId(tx.allocate().getPageId());
                              pl.load(tx);
                              metaData.lists.put(tx, name, pl);
                          }
                      });
                      result = pl;
                      this.persistentLists.put(name, pl);
                  }
                  final PListImpl toLoad = result;
                  getPageFile().tx().execute(new Transaction.Closure<IOException>() {
                      @Override
                      public void execute(Transaction tx) throws IOException {
                          toLoad.load(tx);
                      }
                  });
  
                  return result;
              }
          }
      }
  
      @Override
      public boolean removePList(final String name) throws Exception {
          boolean result = false;
          synchronized (indexLock) {
              synchronized (this) {
                  final PList pl = this.persistentLists.remove(name);
                  result = pl != null;
                  if (result) {
                      getPageFile().tx().execute(new Transaction.Closure<IOException>() {
                          @Override
                          public void execute(Transaction tx) throws IOException {
                              metaData.lists.remove(tx, name);
                              pl.destroy();
                          }
                      });
                  }
              }
          }
          return result;
      }
  
      protected synchronized void intialize() throws Exception {
          if (isStarted()) {
              if (this.initialized == false) {
                  if (this.directory == null) {
                      this.directory = getDefaultDirectory();
                  }
                  IOHelper.mkdirs(this.directory);
                  IOHelper.deleteChildren(this.directory);
                  if (this.indexDirectory != null) {
                      IOHelper.mkdirs(this.indexDirectory);
                      IOHelper.deleteChildren(this.indexDirectory);
                  }
                  lock();
                  this.journal = new Journal();
                  this.journal.setDirectory(directory);
                  this.journal.setMaxFileLength(getJournalMaxFileLength());
                  this.journal.setWriteBatchSize(getJournalMaxWriteBatchSize());
                  this.journal.start();
                  this.pageFile = new PageFile(getIndexDirectory(), "tmpDB");
                  this.pageFile.setEnablePageCaching(getIndexEnablePageCaching());
                  this.pageFile.setPageSize(getIndexPageSize());
                  this.pageFile.setWriteBatchSize(getIndexWriteBatchSize());
                  this.pageFile.setPageCacheSize(getIndexCacheSize());
                  this.pageFile.load();
  
                  this.pageFile.tx().execute(new Transaction.Closure<IOException>() {
                      @Override
                      public void execute(Transaction tx) throws IOException {
                          if (pageFile.getPageCount() == 0) {
                              Page<MetaData> page = tx.allocate();
                              assert page.getPageId() == 0;
                              page.set(metaData);
                              metaData.page = page;
                              metaData.createIndexes(tx);
                              tx.store(metaData.page, metaDataMarshaller, true);
  
                          } else {
                              Page<MetaData> page = tx.load(0, metaDataMarshaller);
                              metaData = page.get();
                              metaData.page = page;
                          }
                          metaData.load(tx);
                          metaData.loadLists(tx, persistentLists);
                      }
                  });
                  this.pageFile.flush();
  
                  if (cleanupInterval > 0) {
                      if (scheduler == null) {
                          scheduler = new Scheduler(PListStoreImpl.class.getSimpleName());
                          scheduler.start();
                      }
                      scheduler.executePeriodically(this, cleanupInterval);
                  }
                  this.initialized = true;
                  LOG.info(this + " initialized");
              }
          }
      }
  
      protected File getDefaultDirectory() {
          return new File(IOHelper.getDefaultDataDirectory() + File.pathSeparator + "delayedDB");
      }
  
      protected void cleanupDirectory(final File dir) {
          if (dir != null && dir.exists()) {
              IOHelper.delete(dir);
          }
      }
  
      @Override
      protected synchronized void doStart() throws Exception {
          if (!lazyInit) {
              intialize();
          } else {
              if (this.directory == null) {
                  this.directory = getDefaultDirectory();
              }
              //Go ahead and clean up previous data on start up
              cleanupDirectory(this.directory);
              cleanupDirectory(this.indexDirectory);
          }
          LOG.info(this + " started");
      }
  
      @Override
      protected synchronized void doStop(ServiceStopper stopper) throws Exception {
          if (scheduler != null) {
              if (PListStoreImpl.class.getSimpleName().equals(scheduler.getName())) {
                  scheduler.stop();
                  scheduler = null;
              }
          }
          for (PListImpl pl : this.persistentLists.values()) {
              pl.unload(null);
          }
          if (this.pageFile != null) {
              this.pageFile.unload();
          }
          if (this.journal != null) {
              journal.close();
          }
          if (this.lockFile != null) {
              this.lockFile.unlock();
          }
          this.lockFile = null;
          this.initialized = false;
          LOG.info(this + " stopped");
  
      }
  
      @Override
      public void run() {
          try {
              if (isStopping()) {
                  return;
              }
              final int lastJournalFileId = journal.getLastAppendLocation().getDataFileId();
              final Set<Integer> candidates = journal.getFileMap().keySet();
              LOG.trace("Full gc candidate set:" + candidates);
              if (candidates.size() > 1) {
                  // prune current write
                  for (Iterator<Integer> iterator = candidates.iterator(); iterator.hasNext();) {
                      if (iterator.next() >= lastJournalFileId) {
                          iterator.remove();
                      }
                  }
                  List<PListImpl> plists = null;
                  synchronized (indexLock) {
                      synchronized (this) {
                          plists = new ArrayList<PListImpl>(persistentLists.values());
                      }
                  }
                  for (PListImpl list : plists) {
                      list.claimFileLocations(candidates);
                      if (isStopping()) {
                          return;
                      }
                      LOG.trace("Remaining gc candidate set after refs from: " + list.getName() + ":" + candidates);
                  }
                  LOG.trace("GC Candidate set:" + candidates);
                  this.journal.removeDataFiles(candidates);
              }
          } catch (IOException e) {
              LOG.error("Exception on periodic cleanup: " + e, e);
          }
      }
  
      ByteSequence getPayload(Location location) throws IllegalStateException, IOException {
          ByteSequence result = null;
          result = this.journal.read(location);
          return result;
      }
  
      Location write(ByteSequence payload, boolean sync) throws IllegalStateException, IOException {
          return this.journal.write(payload, sync);
      }
  
      private void lock() throws IOException {
          if (lockFile == null) {
              File lockFileName = new File(directory, "lock");
              lockFile = new LockFile(lockFileName, true);
              if (failIfDatabaseIsLocked) {
                  lockFile.lock();
              } else {
                  while (true) {
                      try {
                          lockFile.lock();
                          break;
                      } catch (IOException e) {
                          LOG.info("Database " + lockFileName + " is locked... waiting "
                                  + (DATABASE_LOCKED_WAIT_DELAY / 1000)
                                  + " seconds for the database to be unlocked. Reason: " + e);
                          try {
                              Thread.sleep(DATABASE_LOCKED_WAIT_DELAY);
                          } catch (InterruptedException e1) {
                          }
                      }
                  }
              }
          }
      }
  
      PageFile getPageFile() {
          this.pageFile.isLoaded();
          return this.pageFile;
      }
  
      public boolean isFailIfDatabaseIsLocked() {
          return failIfDatabaseIsLocked;
      }
  
      public void setFailIfDatabaseIsLocked(boolean failIfDatabaseIsLocked) {
          this.failIfDatabaseIsLocked = failIfDatabaseIsLocked;
      }
  
      @Override
      public int getJournalMaxFileLength() {
          return journalMaxFileLength;
      }
  
      public void setJournalMaxFileLength(int journalMaxFileLength) {
          this.journalMaxFileLength = journalMaxFileLength;
      }
  
      public int getJournalMaxWriteBatchSize() {
          return journalMaxWriteBatchSize;
      }
  
      public void setJournalMaxWriteBatchSize(int journalMaxWriteBatchSize) {
          this.journalMaxWriteBatchSize = journalMaxWriteBatchSize;
      }
  
      public boolean isEnableIndexWriteAsync() {
          return enableIndexWriteAsync;
      }
  
      public void setEnableIndexWriteAsync(boolean enableIndexWriteAsync) {
          this.enableIndexWriteAsync = enableIndexWriteAsync;
      }
  
      public long getCleanupInterval() {
          return cleanupInterval;
      }
  
      public void setCleanupInterval(long cleanupInterval) {
          this.cleanupInterval = cleanupInterval;
      }
  
      public boolean isLazyInit() {
          return lazyInit;
      }
  
      public void setLazyInit(boolean lazyInit) {
          this.lazyInit = lazyInit;
      }
  
      @Override
      public String toString() {
          String path = getDirectory() != null ? getDirectory().getAbsolutePath() : "DIRECTORY_NOT_SET";
          if (indexDirectory != null) {
              path += "|" + indexDirectory.getAbsolutePath();
          }
          return "PListStore:[" + path + "]";
      }
  }
  