BitSharp.Esent.EsentBlockTxesStorage.ReadBlockTransactions C# (CSharp) Method

        private IEnumerator<BlockTxNode> ReadBlockTransactions(UInt256 blockHash, bool requireTx)
        {
            using (var handle = this.cursorCache.TakeItem())
            {
                var cursor = handle.Item;

                using (var jetTx = cursor.jetSession.BeginTransaction())
                {
                    int blockIndex;
                    if (!TryGetBlockIndex(cursor, blockHash, out blockIndex))
                        throw new MissingDataException(blockHash);

                    Api.JetSetCurrentIndex(cursor.jetSession, cursor.blocksTableId, "IX_BlockIndexTxIndex");

                    Api.MakeKey(cursor.jetSession, cursor.blocksTableId, blockIndex, MakeKeyGrbit.NewKey);
                    Api.MakeKey(cursor.jetSession, cursor.blocksTableId, 0, MakeKeyGrbit.None);
                    if (!Api.TrySeek(cursor.jetSession, cursor.blocksTableId, SeekGrbit.SeekGE))
                        throw new MissingDataException(blockHash);

                    Api.MakeKey(cursor.jetSession, cursor.blocksTableId, blockIndex, MakeKeyGrbit.NewKey);
                    Api.MakeKey(cursor.jetSession, cursor.blocksTableId, int.MaxValue, MakeKeyGrbit.None);
                    if (!Api.TrySetIndexRange(cursor.jetSession, cursor.blocksTableId, SetIndexRangeGrbit.RangeUpperLimit))
                        throw new MissingDataException(blockHash);

                    do
                    {
                        var txIndexColumn = new Int32ColumnValue { Columnid = cursor.txIndexColumnId };
                        var blockDepthColumn = new Int32ColumnValue { Columnid = cursor.blockDepthColumnId };
                        var blockTxHashColumn = new BytesColumnValue { Columnid = cursor.blockTxHashColumnId };
                        var blockTxBytesColumn = new BytesColumnValue { Columnid = cursor.blockTxBytesColumnId };
                        Api.RetrieveColumns(cursor.jetSession, cursor.blocksTableId, txIndexColumn, blockDepthColumn, blockTxHashColumn, blockTxBytesColumn);

                        var txIndex = txIndexColumn.Value.Value;
                        var depth = blockDepthColumn.Value.Value;
                        var txHash = DbEncoder.DecodeUInt256(blockTxHashColumn.Value);
                        var txBytes = blockTxBytesColumn.Value;

                        // determine if transaction is pruned by its depth
                        var pruned = depth >= 0;
                        depth = Math.Max(0, depth);

                        if (pruned && requireTx)
                            throw new MissingDataException(blockHash);

                        var blockTxNode = new BlockTxNode(txIndex, depth, txHash, pruned, txBytes?.ToImmutableArray());

                        yield return blockTxNode;
                    }
                    while (Api.TryMoveNext(cursor.jetSession, cursor.blocksTableId));
                }
            }
        }