Lucene.Net.Store.Azure.AzureDirectory.OpenInput C# (CSharp) Method

        public override IndexInput OpenInput(System.String name)
        {
            try
            {
                var blob = _blobContainer.GetBlockBlobReference(_rootFolder + name);
                blob.FetchAttributes();
                return new AzureIndexInput(this, blob);
            }
            catch (Exception err)
            {
                throw new FileNotFoundException(name, err);
            }
        }

        private static void UnidirectionalSync(AzureDirectory sourceDirectory, Directory destinationDirectory)
        {
            var sourceFiles = sourceDirectory.ListAll();

            var fileNameFilter = IndexFileNameFilter.Filter;
            byte[] buffer = new byte[16384];

            foreach (string sourceFile in sourceFiles)
            {
                // only copy file if it is accepted by Lucene's default filter
                // and it does not already exist (except for segment map files, we always want those)
                if (fileNameFilter.Accept(null, sourceFile) && (!destinationDirectory.FileExists(sourceFile) || sourceFile.StartsWith("segment")))
                {
                    IndexOutput indexOutput = null;
                    IndexInput indexInput = null;
                    try
                    {
                        indexOutput = destinationDirectory.CreateOutput(sourceFile);
                        indexInput = sourceDirectory.OpenInput(sourceFile);

                        long length = indexInput.Length();
                        long position = 0;
                        while (position < length)
                        {
                            int bytesToRead = position + 16384L > length ? (int)(length - position) : 16384;
                            indexInput.ReadBytes(buffer, 0, bytesToRead);
                            indexOutput.WriteBytes(buffer, bytesToRead);

                            position += bytesToRead;
                        }
                    }
                    finally
                    {
                        try
                        {
                            indexOutput?.Close();
                        }
                        finally
                        {
                            indexInput?.Close();
                        }
                    }
                }
            }

            // we'll remove old files from both AzureDirectory's cache directory, as well as our destination directory
            // (only when older than 45 minutes - old files may still have active searches on them so we need a margin)
            var referenceTimestamp = LuceneTimestampFromDateTime(DateTime.UtcNow.AddMinutes(-45));

            // remove old files from AzureDirectory cache directory
            RemoveOldFiles(sourceDirectory.CacheDirectory, sourceFiles, referenceTimestamp);

            // remove old files from destination directory
            RemoveOldFiles(destinationDirectory, sourceFiles, referenceTimestamp);
        }