hdfs-sequence-table-writer.h

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// Copyright 2012 Cloudera Inc.
//
// Licensed 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.

#ifndef IMPALA_EXEC_HDFS_SEQUENCE_WRITER_H
#define IMPALA_EXEC_HDFS_SEQUENCE_WRITER_H

#include <hdfs.h>
#include <sstream>

#include "runtime/descriptors.h"
#include "exec/hdfs-table-sink.h"
#include "exec/hdfs-table-writer.h"
#include "util/codec.h"
#include "write-stream.h"

namespace impala {

class Expr;
class TupleDescriptor;
class TupleRow;
class RuntimeState;
struct StringValue;
struct OutputPartition;

class HdfsSequenceTableWriter : public HdfsTableWriter {
 public:
  HdfsSequenceTableWriter(HdfsTableSink* parent,
                          RuntimeState* state, OutputPartition* output,
                          const HdfsPartitionDescriptor* partition,
                          const HdfsTableDescriptor* table_desc,
                          const std::vector<ExprContext*>& output_exprs);

  ~HdfsSequenceTableWriter() { }

  virtual Status Init();
  virtual Status Finalize() { return Flush(); }
  virtual Status InitNewFile() { return WriteFileHeader(); }
  virtual void Close() { return; }
  virtual uint64_t default_block_size() const { return 0; }
  virtual std::string file_extension() const { return "seq"; }

  virtual Status AppendRowBatch(RowBatch* rows,
                                const std::vector<int32_t>& row_group_indices,
                                bool* new_file);

 private:
  inline Status ConsumeRow(TupleRow* row);

  Status WriteFileHeader();

  Status WriteCompressedBlock();

  inline void EncodeRow(TupleRow* row, WriteStream* buf);

  inline void WriteEscapedString(const StringValue* str_val, WriteStream* buf);

  Status Flush();

  uint64_t approx_block_size_;

  WriteStream out_;

  WriteStream row_buf_;

  MemPool* mem_pool_;

  bool compress_flag_;

  uint64_t unflushed_rows_;

  std::string codec_name_;
  boost::scoped_ptr<Codec> compressor_;

  bool record_compression_;

  char field_delim_;

  char escape_char_;

  std::string sync_marker_;
  std::string neg1_sync_marker_;

  static const char* VALUE_CLASS_NAME;
  static uint8_t SEQ6_CODE[4];
};

} // namespace impala
#endif