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.cassandra.index.sai.disk.v1;
  
  import java.io.IOException;
  import java.nio.ByteBuffer;
  
  import org.apache.cassandra.index.sai.disk.io.IndexFileUtils;
  import org.apache.cassandra.index.sai.disk.v1.postings.PostingsReader;
  import org.apache.cassandra.index.sai.disk.v1.postings.ScanningPostingsReader;
  import org.apache.cassandra.index.sai.disk.v1.trie.TrieTermsIterator;
  import org.apache.cassandra.index.sai.postings.PostingList;
  import org.apache.cassandra.index.sai.utils.IndexEntry;
  import org.apache.cassandra.index.sai.utils.TermsIterator;
  import org.apache.cassandra.io.util.FileHandle;
  import org.apache.cassandra.io.util.FileUtils;
  import org.apache.cassandra.utils.Pair;
  import org.apache.cassandra.utils.Throwables;
  import org.apache.cassandra.utils.bytecomparable.ByteComparable;
  import org.apache.cassandra.utils.bytecomparable.ByteSource;
  import org.apache.cassandra.utils.bytecomparable.ByteSourceInverse;
  import org.apache.lucene.store.IndexInput;
  
  public class TermsScanner implements TermsIterator
  {
      private final FileHandle postingsFile;
      private final TrieTermsIterator iterator;
      private final ByteBuffer minTerm, maxTerm;
      private Pair<ByteComparable, Long> entry;
  
      public TermsScanner(FileHandle termFile, FileHandle postingsFile, long trieRoot)
      {
          this.postingsFile = postingsFile;
          this.iterator = new TrieTermsIterator(termFile.instantiateRebufferer(null), trieRoot);
          this.minTerm = ByteBuffer.wrap(ByteSourceInverse.readBytes(ByteSourceInverse.unescape(ByteSource.peekable(iterator.getMinTerm().asComparableBytes(ByteComparable.Version.OSS50)))));
          this.maxTerm = ByteBuffer.wrap(ByteSourceInverse.readBytes(ByteSourceInverse.unescape(ByteSource.peekable(iterator.getMaxTerm().asComparableBytes(ByteComparable.Version.OSS50)))));
      }
  
  
      @Override
      public void close()
      {
          FileUtils.closeQuietly(postingsFile);
          iterator.close();
      }
  
      @Override
      public ByteBuffer getMinTerm()
      {
          return minTerm;
      }
  
      @Override
      public ByteBuffer getMaxTerm()
      {
          return maxTerm;
      }
  
      @Override
      public IndexEntry next()
      {
          if (iterator.hasNext())
          {
              entry = iterator.next();
              return IndexEntry.create(entry.left, postings());
          }
          return null;
      }
  
      @Override
      public boolean hasNext()
      {
          return iterator.hasNext();
      }
  
      private PostingList postings()
      {
          assert entry != null;
          final IndexInput input = IndexFileUtils.instance.openInput(postingsFile);
          try
          {
              return new ScanningPostingsReader(input, new PostingsReader.BlocksSummary(input, entry.right));
          }
          catch (IOException e)
          {
              throw Throwables.unchecked(e);
          }
      }
  }
  