internal virtual SegmentReader ReopenSegment(SegmentInfo si)
        {
            lock (this)
            {
                bool deletionsUpToDate = (this.si.HasDeletions() == si.HasDeletions()) && (!si.HasDeletions() || this.si.GetDelFileName().Equals(si.GetDelFileName()));
                bool normsUpToDate     = true;


                bool[] fieldNormsChanged = new bool[fieldInfos.Size()];
                if (normsUpToDate)
                {
                    for (int i = 0; i < fieldInfos.Size(); i++)
                    {
                        if (!this.si.GetNormFileName(i).Equals(si.GetNormFileName(i)))
                        {
                            normsUpToDate        = false;
                            fieldNormsChanged[i] = true;
                        }
                    }
                }

                if (normsUpToDate && deletionsUpToDate)
                {
                    return(this);
                }


                // clone reader
                SegmentReader clone;
                if (readOnly)
                {
                    clone = new ReadOnlySegmentReader();
                }
                else
                {
                    clone = new SegmentReader();
                }

                bool success = false;
                try
                {
                    clone.readOnly       = readOnly;
                    clone.directory      = directory;
                    clone.si             = si;
                    clone.segment        = segment;
                    clone.readBufferSize = readBufferSize;
                    clone.cfsReader      = cfsReader;
                    clone.storeCFSReader = storeCFSReader;

                    clone.fieldInfos            = fieldInfos;
                    clone.tis                   = tis;
                    clone.freqStream            = freqStream;
                    clone.proxStream            = proxStream;
                    clone.termVectorsReaderOrig = termVectorsReaderOrig;


                    // we have to open a new FieldsReader, because it is not thread-safe
                    // and can thus not be shared among multiple SegmentReaders
                    // TODO: Change this in case FieldsReader becomes thread-safe in the future
                    System.String fieldsSegment;

                    Directory storeDir = Directory();

                    if (si.GetDocStoreOffset() != -1)
                    {
                        fieldsSegment = si.GetDocStoreSegment();
                        if (storeCFSReader != null)
                        {
                            storeDir = storeCFSReader;
                        }
                    }
                    else
                    {
                        fieldsSegment = segment;
                        if (cfsReader != null)
                        {
                            storeDir = cfsReader;
                        }
                    }

                    if (fieldsReader != null)
                    {
                        clone.fieldsReader = new FieldsReader(storeDir, fieldsSegment, fieldInfos, readBufferSize, si.GetDocStoreOffset(), si.docCount);
                    }


                    if (!deletionsUpToDate)
                    {
                        // load deleted docs
                        clone.deletedDocs = null;
                        clone.LoadDeletedDocs();
                    }
                    else
                    {
                        clone.deletedDocs = this.deletedDocs;
                    }

                    clone.norms = new System.Collections.Hashtable();
                    if (!normsUpToDate)
                    {
                        // load norms
                        for (int i = 0; i < fieldNormsChanged.Length; i++)
                        {
                            // copy unchanged norms to the cloned reader and incRef those norms
                            if (!fieldNormsChanged[i])
                            {
                                System.String curField = fieldInfos.FieldInfo(i).name;
                                Norm          norm     = (Norm)this.norms[curField];
                                norm.IncRef();
                                clone.norms[curField] = norm;
                            }
                        }

                        clone.OpenNorms(si.GetUseCompoundFile() ? cfsReader : Directory(), readBufferSize);
                    }
                    else
                    {
                        System.Collections.IEnumerator it = norms.Keys.GetEnumerator();
                        while (it.MoveNext())
                        {
                            System.String field = (System.String)it.Current;
                            Norm          norm  = (Norm)norms[field];
                            norm.IncRef();
                            clone.norms[field] = norm;
                        }
                    }

                    if (clone.singleNormStream == null)
                    {
                        for (int i = 0; i < fieldInfos.Size(); i++)
                        {
                            FieldInfo fi = fieldInfos.FieldInfo(i);
                            if (fi.isIndexed && !fi.omitNorms)
                            {
                                Directory     d        = si.GetUseCompoundFile() ? cfsReader : Directory();
                                System.String fileName = si.GetNormFileName(fi.number);
                                if (si.HasSeparateNorms(fi.number))
                                {
                                    continue;
                                }

                                if (fileName.EndsWith("." + IndexFileNames.NORMS_EXTENSION))
                                {
                                    clone.singleNormStream = d.OpenInput(fileName, readBufferSize);
                                    break;
                                }
                            }
                        }
                    }

                    success = true;
                }
                finally
                {
                    if (this.referencedSegmentReader != null)
                    {
                        // this reader shares resources with another SegmentReader,
                        // so we increment the other readers refCount. We don't
                        // increment the refCount of the norms because we did
                        // that already for the shared norms
                        clone.referencedSegmentReader = this.referencedSegmentReader;
                        referencedSegmentReader.IncRefReaderNotNorms();
                    }
                    else
                    {
                        // this reader wasn't reopened, so we increment this
                        // readers refCount
                        clone.referencedSegmentReader = this;
                        IncRefReaderNotNorms();
                    }

                    if (!success)
                    {
                        // An exception occured during reopen, we have to decRef the norms
                        // that we incRef'ed already and close singleNormsStream and FieldsReader
                        clone.DecRef();
                    }
                }

                return(clone);
            }
        }
 protected internal override void  AcquireWriteLock()
 {
     ReadOnlySegmentReader.NoWrite();
 }
        internal virtual SegmentReader ReopenSegment(SegmentInfo si)
        {
            lock (this)
            {
                bool deletionsUpToDate = (this.si.HasDeletions() == si.HasDeletions()) && (!si.HasDeletions() || this.si.GetDelFileName().Equals(si.GetDelFileName()));
                bool normsUpToDate = true;

                bool[] fieldNormsChanged = new bool[fieldInfos.Size()];
                if (normsUpToDate)
                {
                    for (int i = 0; i < fieldInfos.Size(); i++)
                    {
                        if (!this.si.GetNormFileName(i).Equals(si.GetNormFileName(i)))
                        {
                            normsUpToDate = false;
                            fieldNormsChanged[i] = true;
                        }
                    }
                }

                if (normsUpToDate && deletionsUpToDate)
                {
                    return this;
                }

                // clone reader
                SegmentReader clone;
                if (readOnly)
                    clone = new ReadOnlySegmentReader();
                else
                    clone = new SegmentReader();

                bool success = false;
                try
                {
                    clone.readOnly = readOnly;
                    clone.directory = directory;
                    clone.si = si;
                    clone.segment = segment;
                    clone.readBufferSize = readBufferSize;
                    clone.cfsReader = cfsReader;
                    clone.storeCFSReader = storeCFSReader;

                    clone.fieldInfos = fieldInfos;
                    clone.tis = tis;
                    clone.freqStream = freqStream;
                    clone.proxStream = proxStream;
                    clone.termVectorsReaderOrig = termVectorsReaderOrig;

                    // we have to open a new FieldsReader, because it is not thread-safe
                    // and can thus not be shared among multiple SegmentReaders
                    // TODO: Change this in case FieldsReader becomes thread-safe in the future
                    System.String fieldsSegment;

                    Directory storeDir = Directory();

                    if (si.GetDocStoreOffset() != - 1)
                    {
                        fieldsSegment = si.GetDocStoreSegment();
                        if (storeCFSReader != null)
                        {
                            storeDir = storeCFSReader;
                        }
                    }
                    else
                    {
                        fieldsSegment = segment;
                        if (cfsReader != null)
                        {
                            storeDir = cfsReader;
                        }
                    }

                    if (fieldsReader != null)
                    {
                        clone.fieldsReader = new FieldsReader(storeDir, fieldsSegment, fieldInfos, readBufferSize, si.GetDocStoreOffset(), si.docCount);
                    }

                    if (!deletionsUpToDate)
                    {
                        // load deleted docs
                        clone.deletedDocs = null;
                        clone.LoadDeletedDocs();
                    }
                    else
                    {
                        clone.deletedDocs = this.deletedDocs;
                    }

                    clone.norms = new System.Collections.Hashtable();
                    if (!normsUpToDate)
                    {
                        // load norms
                        for (int i = 0; i < fieldNormsChanged.Length; i++)
                        {
                            // copy unchanged norms to the cloned reader and incRef those norms
                            if (!fieldNormsChanged[i])
                            {
                                System.String curField = fieldInfos.FieldInfo(i).name;
                                Norm norm = (Norm) this.norms[curField];
                                norm.IncRef();
                                clone.norms[curField] = norm;
                            }
                        }

                        clone.OpenNorms(si.GetUseCompoundFile() ? cfsReader : Directory(), readBufferSize);
                    }
                    else
                    {
                        System.Collections.IEnumerator it = norms.Keys.GetEnumerator();
                        while (it.MoveNext())
                        {
                            System.String field = (System.String) it.Current;
                            Norm norm = (Norm) norms[field];
                            norm.IncRef();
                            clone.norms[field] = norm;
                        }
                    }

                    if (clone.singleNormStream == null)
                    {
                        for (int i = 0; i < fieldInfos.Size(); i++)
                        {
                            FieldInfo fi = fieldInfos.FieldInfo(i);
                            if (fi.isIndexed && !fi.omitNorms)
                            {
                                Directory d = si.GetUseCompoundFile() ? cfsReader : Directory();
                                System.String fileName = si.GetNormFileName(fi.number);
                                if (si.HasSeparateNorms(fi.number))
                                {
                                    continue;
                                }

                                if (fileName.EndsWith("." + IndexFileNames.NORMS_EXTENSION))
                                {
                                    clone.singleNormStream = d.OpenInput(fileName, readBufferSize);
                                    break;
                                }
                            }
                        }
                    }

                    success = true;
                }
                finally
                {
                    if (this.referencedSegmentReader != null)
                    {
                        // this reader shares resources with another SegmentReader,
                        // so we increment the other readers refCount. We don't
                        // increment the refCount of the norms because we did
                        // that already for the shared norms
                        clone.referencedSegmentReader = this.referencedSegmentReader;
                        referencedSegmentReader.IncRefReaderNotNorms();
                    }
                    else
                    {
                        // this reader wasn't reopened, so we increment this
                        // readers refCount
                        clone.referencedSegmentReader = this;
                        IncRefReaderNotNorms();
                    }

                    if (!success)
                    {
                        // An exception occured during reopen, we have to decRef the norms
                        // that we incRef'ed already and close singleNormsStream and FieldsReader
                        clone.DecRef();
                    }
                }

                return clone;
            }
        }