/**
 * Global stats on segments.
 */
public final SegmentsStats segmentsStats() {
    ensureOpen();
    try (final Searcher searcher = acquireSearcher("segments_stats", false)) {
        SegmentsStats stats = new SegmentsStats();
        for (LeafReaderContext reader : searcher.reader().leaves()) {
            final SegmentReader segmentReader = segmentReader(reader.reader());
            stats.add(1, segmentReader.ramBytesUsed());
            stats.addTermsMemoryInBytes(guardedRamBytesUsed(segmentReader.getPostingsReader()));
            stats.addStoredFieldsMemoryInBytes(guardedRamBytesUsed(segmentReader.getFieldsReader()));
            stats.addTermVectorsMemoryInBytes(guardedRamBytesUsed(segmentReader.getTermVectorsReader()));
            stats.addNormsMemoryInBytes(guardedRamBytesUsed(segmentReader.getNormsReader()));
            stats.addDocValuesMemoryInBytes(guardedRamBytesUsed(segmentReader.getDocValuesReader()));
        }
        writerSegmentStats(stats);
        return stats;
    }
}
 

@Override
public synchronized Collection<Accountable> getChildResources() {
  final List<Accountable> resources = new ArrayList<>();
  long ramBytesUsed = 0;
  for (LeafReaderContext ctx : indexReader.leaves()) {
    ramBytesUsed += ((SegmentReader) ctx.reader()).ramBytesUsed();
  }
  resources.add(Accountables.namedAccountable("indexReader", ramBytesUsed));
  if (taxoArrays != null) {
    resources.add(Accountables.namedAccountable("taxoArrays", taxoArrays));
  }

  synchronized (categoryCache) {
    resources.add(Accountables.namedAccountable("categoryCache", BYTES_PER_CACHE_ENTRY * categoryCache.size()));
  }    

  synchronized (ordinalCache) {
    resources.add(Accountables.namedAccountable("ordinalCache", BYTES_PER_CACHE_ENTRY * ordinalCache.size()));
  }    
  
  return Collections.unmodifiableList(resources);
}
 

/**
 * Given an IndexReader, asserts that there is at least one AtomcReader leaf,
 * and that all LeafReader leaves are SegmentReader's that have a compound 
 * file status that matches the expected input.
 */
private static void assertCompoundSegments(IndexReader reader, 
                                           boolean compound) {

  assertNotNull("Null leaves", reader.leaves());
  assertTrue("no leaves", 0 < reader.leaves().size());

  for (LeafReaderContext atomic : reader.leaves()) {
    assertTrue("not a segment reader: " + atomic.reader().toString(), 
               atomic.reader() instanceof SegmentReader);
    
    assertEquals("Compound status incorrect for: " + 
                 atomic.reader().toString(),
                 compound,
                 ((SegmentReader)atomic.reader()).getSegmentInfo().info.getUseCompoundFile());
  }
}
 

/**
 * Gets the live docs.
 *
 * @param indexReader the index reader
 * @return the live docs
 */
private static ArrayList<Integer> getLiveDocs(IndexReader indexReader) {
  ArrayList<Integer> list = new ArrayList<>();
  ListIterator<LeafReaderContext> iterator = indexReader.leaves()
      .listIterator();
  while (iterator.hasNext()) {
    LeafReaderContext lrc = iterator.next();
    SegmentReader r = (SegmentReader) lrc.reader();
    for (int docId = 0; docId < r.maxDoc(); docId++) {
      if (r.numDocs() == r.maxDoc() || r.getLiveDocs().get(docId)) {
        list.add(lrc.docBase + docId);
      }
    }
  }
  return list;
}
 

private void writeRowIds(Writer writer, SegmentReader segmentReader) throws IOException {
  Terms terms = segmentReader.terms(BlurConstants.ROW_ID);
  if (terms == null) {
    return;
  }
  TermsEnum termsEnum = terms.iterator(null);
  BytesRef rowId;
  long s = System.nanoTime();
  while ((rowId = termsEnum.next()) != null) {
    long n = System.nanoTime();
    if (n + _10_SECONDS > s) {
      _progressable.progress();
      s = System.nanoTime();
    }
    writer.append(new Text(rowId.utf8ToString()), NullWritable.get());
  }
}
 

protected final DocsStats docsStats(IndexReader indexReader) {
    long numDocs = 0;
    long numDeletedDocs = 0;
    long sizeInBytes = 0;
    // we don't wait for a pending refreshes here since it's a stats call instead we mark it as accessed only which will cause
    // the next scheduled refresh to go through and refresh the stats as well
    for (LeafReaderContext readerContext : indexReader.leaves()) {
        // we go on the segment level here to get accurate numbers
        final SegmentReader segmentReader = Lucene.segmentReader(readerContext.reader());
        SegmentCommitInfo info = segmentReader.getSegmentInfo();
        numDocs += readerContext.reader().numDocs();
        numDeletedDocs += readerContext.reader().numDeletedDocs();
        try {
            sizeInBytes += info.sizeInBytes();
        } catch (IOException e) {
            logger.trace(() -> new ParameterizedMessage("failed to get size for [{}]", info.info.name), e);
        }
    }
    return new DocsStats(numDocs, numDeletedDocs, sizeInBytes);
}
 

private void fillSegmentInfo(SegmentReader segmentReader, boolean verbose, boolean search, Map<String, Segment> segments) {
    SegmentCommitInfo info = segmentReader.getSegmentInfo();
    assert segments.containsKey(info.info.name) == false;
    Segment segment = new Segment(info.info.name);
    segment.search = search;
    segment.docCount = segmentReader.numDocs();
    segment.delDocCount = segmentReader.numDeletedDocs();
    segment.version = info.info.getVersion();
    segment.compound = info.info.getUseCompoundFile();
    try {
        segment.sizeInBytes = info.sizeInBytes();
    } catch (IOException e) {
        logger.trace(() -> new ParameterizedMessage("failed to get size for [{}]", info.info.name), e);
    }
    segment.memoryInBytes = segmentReader.ramBytesUsed();
    segment.segmentSort = info.info.getIndexSort();
    if (verbose) {
        segment.ramTree = Accountables.namedAccountable("root", segmentReader);
    }
    segment.attributes = info.info.getAttributes();
    // TODO: add more fine grained mem stats values to per segment info here
    segments.put(info.info.name, segment);
}
 

DirectoryReaderWithAllLiveDocs(DirectoryReader in) throws IOException {
    super(in, new SubReaderWrapper() {
        @Override
        public LeafReader wrap(LeafReader leaf) {
            SegmentReader segmentReader = segmentReader(leaf);
            Bits hardLiveDocs = segmentReader.getHardLiveDocs();
            if (hardLiveDocs == null) {
                return new LeafReaderWithLiveDocs(leaf, null, leaf.maxDoc());
            }
            // TODO: Can we avoid calculate numDocs by using SegmentReader#getSegmentInfo with LUCENE-8458?
            int numDocs = 0;
            for (int i = 0; i < hardLiveDocs.length(); i++) {
                if (hardLiveDocs.get(i)) {
                    numDocs++;
                }
            }
            return new LeafReaderWithLiveDocs(segmentReader, hardLiveDocs, numDocs);
        }
    });
}
 

/**
 * Tries to extract a segment reader from the given index reader.
 * If no SegmentReader can be extracted an {@link IllegalStateException} is thrown.
 */
protected static SegmentReader segmentReader(LeafReader reader) {
    if (reader instanceof SegmentReader) {
        return (SegmentReader) reader;
    } else if (reader instanceof FilterLeafReader) {
        final FilterLeafReader fReader = (FilterLeafReader) reader;
        return segmentReader(FilterLeafReader.unwrap(fReader));
    }
    // hard fail - we can't get a SegmentReader
    throw new IllegalStateException("Can not extract segment reader from given index reader [" + reader + "]");
}
 

/** Returns the sum of RAM bytes used by each segment */
private static long getIndexHeapUsed(DirectoryReader reader) {
	long indexHeapRamBytesUsed = 0;
	for (LeafReaderContext leafReaderContext : reader.leaves()) {
		LeafReader leafReader = leafReaderContext.reader();
		if (leafReader instanceof SegmentReader) {
			indexHeapRamBytesUsed += ((SegmentReader) leafReader)
					.ramBytesUsed();
		} else {
			// Not supported for any reader that is not a SegmentReader
			return -1;
		}
	}
	return indexHeapRamBytesUsed;
}
 

private void initReader(AtomicReader reader) {
  if (reader instanceof SegmentReader) {
    reader.addCoreClosedListener(purgeCore);
  } else {
    // we have a slow reader of some sort, try to register a purge event
    // rather than relying on gc:
    Object key = reader.getCoreCacheKey();
    if (key instanceof AtomicReader) {
      ((AtomicReader) key).addReaderClosedListener(purgeReader);
    } else {
      // last chance
      reader.addReaderClosedListener(purgeReader);
    }
  }
}
 

@Override
public long ramBytesUsed() {
  long mem = RamUsageEstimator.shallowSizeOf(this);
  try {
    if (searcherMgr != null) {
      SearcherManager mgr;
      IndexSearcher searcher;
      synchronized (searcherMgrLock) {
        mgr = searcherMgr; // acquire & release on same SearcherManager, via local reference
        searcher = mgr.acquire();
      }
      try {
        for (LeafReaderContext context : searcher.getIndexReader().leaves()) {
          LeafReader reader = FilterLeafReader.unwrap(context.reader());
          if (reader instanceof SegmentReader) {
            mem += ((SegmentReader) context.reader()).ramBytesUsed();
          }
        }
      } finally {
        mgr.release(searcher);
      }
    }
    return mem;
  } catch (IOException ioe) {
    throw new RuntimeException(ioe);
  }
}
 

@Override
public Collection<Accountable> getChildResources() {
  List<Accountable> resources = new ArrayList<>();
  try {
    if (searcherMgr != null) {
      SearcherManager mgr;
      IndexSearcher searcher;
      synchronized (searcherMgrLock) {
        mgr = searcherMgr; // acquire & release on same SearcherManager, via local reference
        searcher = mgr.acquire();
      }
      try {
        for (LeafReaderContext context : searcher.getIndexReader().leaves()) {
          LeafReader reader = FilterLeafReader.unwrap(context.reader());
          if (reader instanceof SegmentReader) {
            resources.add(Accountables.namedAccountable("segment", (SegmentReader)reader));
          }
        }
      } finally {
        mgr.release(searcher);
      }
    }
    return Collections.unmodifiableList(resources);
  } catch (IOException ioe) {
    throw new RuntimeException(ioe);
  }
}
 

private void createCacheFile(Path file, SegmentKey segmentKey) throws IOException {
  LOG.info("Building cache for segment [{0}] to [{1}]", segmentKey, file);
  Path tmpPath = getTmpWriterPath(file.getParent());
  try (Writer writer = createWriter(_configuration, tmpPath)) {
    DirectoryReader reader = getReader();
    for (AtomicReaderContext context : reader.leaves()) {
      SegmentReader segmentReader = AtomicReaderUtil.getSegmentReader(context.reader());
      if (segmentReader.getSegmentName().equals(segmentKey.getSegmentName())) {
        writeRowIds(writer, segmentReader);
        break;
      }
    }
  }
  commitWriter(_configuration, file, tmpPath);
}
 

@SuppressWarnings("unchecked")
private static boolean isFiltered(int notAdjustedDocId, IndexReader reader, Filter filter) throws IOException {
  if (filter == null) {
    return false;
  }
  if (reader instanceof BaseCompositeReader) {
    BaseCompositeReader<IndexReader> indexReader = (BaseCompositeReader<IndexReader>) reader;
    List<? extends IndexReader> sequentialSubReaders = BaseCompositeReaderUtil.getSequentialSubReaders(indexReader);
    int readerIndex = BaseCompositeReaderUtil.readerIndex(indexReader, notAdjustedDocId);
    int readerBase = BaseCompositeReaderUtil.readerBase(indexReader, readerIndex);
    int docId = notAdjustedDocId - readerBase;
    IndexReader orgReader = sequentialSubReaders.get(readerIndex);
    SegmentReader sReader = AtomicReaderUtil.getSegmentReader(orgReader);
    if (sReader != null) {
      SegmentReader segmentReader = (SegmentReader) sReader;
      DocIdSet docIdSet = filter.getDocIdSet(segmentReader.getContext(), segmentReader.getLiveDocs());
      DocIdSetIterator iterator = docIdSet.iterator();
      if (iterator == null) {
        return true;
      }
      if (iterator.advance(docId) == docId) {
        return false;
      }
      return true;
    }
    throw new RuntimeException("Reader has to be a SegmentReader [" + orgReader + "]");
  } else {
    throw new RuntimeException("Reader has to be a BaseCompositeReader [" + reader + "]");
  }
}
 

@Override
public DocIdSet getDocIdSet(AtomicReaderContext context, Bits acceptDocs) throws IOException {
  AtomicReader reader = context.reader();
  Object key = reader.getCoreCacheKey();
  DocIdSet docIdSet = _cache.get(key);
  if (docIdSet != null) {
    _hits.incrementAndGet();
    return BitsFilteredDocIdSet.wrap(docIdSet, acceptDocs);
  }
  // This will only allow a single instance be created per reader per filter
  Object lock = getLock(key);
  synchronized (lock) {
    SegmentReader segmentReader = getSegmentReader(reader);
    if (segmentReader == null) {
      LOG.warn("Could not find SegmentReader from [{0}]", reader);
      return _filter.getDocIdSet(context, acceptDocs);
    }
    Directory directory = getDirectory(segmentReader);
    if (directory == null) {
      LOG.warn("Could not find Directory from [{0}]", segmentReader);
      return _filter.getDocIdSet(context, acceptDocs);
    }
    _misses.incrementAndGet();
    String segmentName = segmentReader.getSegmentName();
    docIdSet = docIdSetToCache(_filter.getDocIdSet(context, null), reader, segmentName, directory);
    _cache.put(key, docIdSet);
    return BitsFilteredDocIdSet.wrap(docIdSet, acceptDocs);
  }
}
 

private long doCountResults(IndexSearcher searcher,
    SearchQueryRequest aRequest, MtasSpanQuery q) throws IOException
{
    ListIterator<LeafReaderContext> leafReaderContextIterator = searcher.getIndexReader()
            .leaves().listIterator();

    Map<Long, Long> annotatableDocuments = listAnnotatableDocuments(aRequest.getProject(),
        aRequest.getUser());

    final float boost = 0;
    SpanWeight spanweight = q.rewrite(searcher.getIndexReader()).createWeight(searcher, false,
            boost);

    long numResults = 0;

    while (leafReaderContextIterator.hasNext()) {
        LeafReaderContext leafReaderContext = leafReaderContextIterator.next();
        try {
            Spans spans = spanweight.getSpans(leafReaderContext, SpanWeight.Postings.POSITIONS);
            SegmentReader segmentReader = (SegmentReader) leafReaderContext.reader();
            if (spans != null) {
                while (spans.nextDoc() != Spans.NO_MORE_DOCS) {
                    if (segmentReader.numDocs() == segmentReader.maxDoc()
                            || segmentReader.getLiveDocs().get(spans.docID())) {
                        Document document = segmentReader.document(spans.docID());

                        // Retrieve user
                        String user = document.get(FIELD_USER);

                        // Retrieve source and annotation document ids
                        String rawSourceDocumentId = document.get(FIELD_SOURCE_DOCUMENT_ID);
                        String rawAnnotationDocumentId = document
                                .get(FIELD_ANNOTATION_DOCUMENT_ID);
                        if (rawSourceDocumentId == null || rawAnnotationDocumentId == null) {
                            log.trace("Indexed document lacks source/annotation document IDs"
                                    + " - source: {}, annotation: {}", rawSourceDocumentId,
                                rawAnnotationDocumentId);
                            continue;

                        }
                        long sourceDocumentId = Long.valueOf(rawSourceDocumentId);
                        long annotationDocumentId = Long.valueOf(rawAnnotationDocumentId);

                        // If the query is limited to a given document, skip any results
                        // which are not in the given document
                        Optional<SourceDocument> limitedToDocument = aRequest
                                .getLimitedToDocument();
                        if (limitedToDocument.isPresent() && !Objects
                            .equals(limitedToDocument.get().getId(), sourceDocumentId)) {
                            log.trace("Query limited to document {}, skipping results for "
                                    + "document {}", limitedToDocument.get().getId(),
                                sourceDocumentId);
                            continue;
                        }

                        if (annotatableDocuments.containsKey(sourceDocumentId)
                            && annotationDocumentId == -1) {
                            // Exclude result if the retrieved document is a sourcedocument
                            // (that is, has annotationDocument = -1) AND it has a
                            // corresponding annotation document for this user
                            log.trace("Skipping results from indexed source document {} in" 
                                + "favor of results from the corresponding annotation "
                                + "document", sourceDocumentId);
                            continue;
                        }
                        else if (annotationDocumentId != -1 && !aRequest.getUser().getUsername()
                            .equals(user)) {
                            // Exclude result if the retrieved document is an annotation
                            // document (that is, annotationDocument != -1 and its username
                            // is different from the quering user
                            log.trace("Skipping results from annotation document for user {} "
                                    + "which does not match the requested user {}", user,
                                aRequest.getUser().getUsername());
                            continue;
                        }

                        while (spans.nextStartPosition() != Spans.NO_MORE_POSITIONS) {
                            numResults++;
                        }
                    }
                }
            }
        }
        catch (Exception e) {
            log.error("Unable to process query results", e);
            numResults = -1;
        }
    }
    return numResults;
}
 

private static void doQuery(IndexReader indexReader, String field, MtasSpanQuery q,
        List<String> prefixes)
    throws IOException
{
    ListIterator<LeafReaderContext> iterator = indexReader.leaves().listIterator();
    IndexSearcher searcher = new IndexSearcher(indexReader);
    final float boost = 0;
    SpanWeight spanweight = q.rewrite(indexReader).createWeight(searcher, false, boost);

    while (iterator.hasNext()) {
        System.out.println("#### new iteration ####");
        LeafReaderContext lrc = iterator.next();
        Spans spans = spanweight.getSpans(lrc, SpanWeight.Postings.POSITIONS);
        SegmentReader segmentReader = (SegmentReader) lrc.reader();
        Terms terms = segmentReader.terms(field);
        CodecInfo mtasCodecInfo = CodecInfo.getCodecInfoFromTerms(terms);
        if (spans != null) {
            while (spans.nextDoc() != Spans.NO_MORE_DOCS) {
                if (segmentReader.numDocs() == segmentReader.maxDoc()
                        || segmentReader.getLiveDocs().get(spans.docID())) {
                    String idValue = segmentReader.document(spans.docID()).getField(FIELD_ID)
                            .stringValue();
                    System.out.println("********  New doc " + spans.docID() + "-" + idValue);
                    while (spans.nextStartPosition() != Spans.NO_MORE_POSITIONS) {
                        System.out.println("------");
                        List<MtasTokenString> tokens = mtasCodecInfo
                                .getPrefixFilteredObjectsByPositions(field, spans.docID(),
                                        prefixes, spans.startPosition(),
                                        (spans.endPosition() - 1));
                        for (MtasTokenString token : tokens) {
                            System.out.print("docId: " + (lrc.docBase + spans.docID()) + ", ");
                            System.out.print(" position: " + token.getPositionStart()
                                    + (!Objects.equals(token.getPositionEnd(),
                                            token.getPositionStart())
                                                    ? "-" + token.getPositionEnd()
                                                    : ""));
                            System.out.print(" offset: " + token.getOffsetStart() + "-"
                                    + token.getOffsetEnd());
                            System.out.print(" mtasId: " + token.getId());
                            System.out.println(" " + token.getPrefix()
                                    + (token.getPostfix() != null ? ":" + token.getPostfix()
                                            : "")
                                    + ", ");
                        }
                        System.out.println("------");
                        List<MtasTreeHit<String>> hits = mtasCodecInfo
                                .getPositionedTermsByPrefixesAndPositionRange(field,
                                        spans.docID(), prefixes, spans.startPosition(),
                                        (spans.endPosition() - 1));
                        for (MtasTreeHit<String> hit : hits) {
                            System.out.print("docId: " + (lrc.docBase + spans.docID()) + ", ");
                            System.out.print("position: " + hit.startPosition
                                    + (hit.endPosition != hit.startPosition
                                            ? "-" + hit.endPosition
                                            : ""));
                            System.out.println(" " + CodecUtil.termPrefix(hit.data)
                                    + (CodecUtil.termValue(hit.data) != null
                                            ? ":" + CodecUtil.termValue(hit.data)
                                            : "")
                                    + ", ");
                        }
                    }
                    // if (prefixes != null && !prefixes.isEmpty()) {
                    // }
                }
            }
        }
    }
}
 

private SimpleOrderedMap<Object> getSegmentInfo(
    SegmentCommitInfo segmentCommitInfo, boolean withSizeInfo, boolean withFieldInfos,
    List<LeafReaderContext> leafContexts, IndexSchema schema) throws IOException {
  SimpleOrderedMap<Object> segmentInfoMap = new SimpleOrderedMap<>();

  segmentInfoMap.add(NAME, segmentCommitInfo.info.name);
  segmentInfoMap.add("delCount", segmentCommitInfo.getDelCount());
  segmentInfoMap.add("softDelCount", segmentCommitInfo.getSoftDelCount());
  segmentInfoMap.add("hasFieldUpdates", segmentCommitInfo.hasFieldUpdates());
  segmentInfoMap.add("sizeInBytes", segmentCommitInfo.sizeInBytes());
  segmentInfoMap.add("size", segmentCommitInfo.info.maxDoc());
  Long timestamp = Long.parseLong(segmentCommitInfo.info.getDiagnostics()
      .get("timestamp"));
  segmentInfoMap.add("age", new Date(timestamp));
  segmentInfoMap.add("source",
      segmentCommitInfo.info.getDiagnostics().get("source"));
  segmentInfoMap.add("version", segmentCommitInfo.info.getVersion().toString());
  // don't open a new SegmentReader - try to find the right one from the leaf contexts
  SegmentReader seg = null;
  for (LeafReaderContext lrc : leafContexts) {
    LeafReader leafReader = lrc.reader();
    leafReader = FilterLeafReader.unwrap(leafReader);
    if (leafReader instanceof SegmentReader) {
      SegmentReader sr = (SegmentReader)leafReader;
      if (sr.getSegmentInfo().info.equals(segmentCommitInfo.info)) {
        seg = sr;
        break;
      }
    }
  }
  if (seg != null) {
    LeafMetaData metaData = seg.getMetaData();
    if (metaData != null) {
      segmentInfoMap.add("createdVersionMajor", metaData.getCreatedVersionMajor());
      segmentInfoMap.add("minVersion", metaData.getMinVersion().toString());
      if (metaData.getSort() != null) {
        segmentInfoMap.add("sort", metaData.getSort().toString());
      }
    }
  }
  if (!segmentCommitInfo.info.getDiagnostics().isEmpty()) {
    segmentInfoMap.add("diagnostics", segmentCommitInfo.info.getDiagnostics());
  }
  if (!segmentCommitInfo.info.getAttributes().isEmpty()) {
    segmentInfoMap.add("attributes", segmentCommitInfo.info.getAttributes());
  }
  if (withSizeInfo) {
    Directory dir = segmentCommitInfo.info.dir;
    List<Pair<String, Long>> files = segmentCommitInfo.files().stream()
        .map(f -> {
          long size = -1;
          try {
            size = dir.fileLength(f);
          } catch (IOException e) {
          }
          return new Pair<String, Long>(f, size);
        }).sorted((p1, p2) -> {
          if (p1.second() > p2.second()) {
            return -1;
          } else if (p1.second() < p2.second()) {
            return 1;
          } else {
            return 0;
          }
        }).collect(Collectors.toList());
    if (!files.isEmpty()) {
      SimpleOrderedMap<Object> topFiles = new SimpleOrderedMap<>();
      for (int i = 0; i < Math.min(files.size(), 5); i++) {
        Pair<String, Long> p = files.get(i);
        topFiles.add(p.first(), RamUsageEstimator.humanReadableUnits(p.second()));
      }
      segmentInfoMap.add("largestFiles", topFiles);
    }
  }
  if (seg != null && withSizeInfo) {
    SimpleOrderedMap<Object> ram = new SimpleOrderedMap<>();
    ram.add("total", seg.ramBytesUsed());
    for (Accountable ac : seg.getChildResources()) {
      accountableToMap(ac, ram::add);
    }
    segmentInfoMap.add("ramBytesUsed", ram);
  }
  if (withFieldInfos) {
    if (seg == null) {
      log.debug("Skipping segment info - not available as a SegmentReader: {}", segmentCommitInfo);
    } else {
      FieldInfos fis = seg.getFieldInfos();
      SimpleOrderedMap<Object> fields = new SimpleOrderedMap<>();
      for (FieldInfo fi : fis) {
        fields.add(fi.name, getFieldInfo(seg, fi, schema));
      }
      segmentInfoMap.add("fields", fields);
    }
  }

  return segmentInfoMap;
}
 

private Directory getDirectory(SegmentReader reader) {
  return reader.directory();
}
 

private SegmentReader getSegmentReader(AtomicReader reader) {
  if (reader instanceof SegmentReader) {
    return (SegmentReader) reader;
  }
  return null;
}