union-node.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_UNION_NODE_H_
#define IMPALA_EXEC_UNION_NODE_H_

#include <boost/scoped_ptr.hpp>

#include "exec/exec-node.h"
#include "exprs/expr.h"
#include "runtime/mem-pool.h"
#include <boost/scoped_ptr.hpp>

namespace impala {

class Tuple;
class TupleRow;

class UnionNode : public ExecNode {
 public:
  UnionNode(ObjectPool* pool, const TPlanNode& tnode, const DescriptorTbl& descs);

  virtual Status Init(const TPlanNode& tnode);
  virtual Status Prepare(RuntimeState* state);
  virtual Status Open(RuntimeState* state);
  virtual Status GetNext(RuntimeState* state, RowBatch* row_batch, bool* eos);
  virtual Status Reset(RuntimeState* state);
  virtual void Close(RuntimeState* state);

 private:
  int tuple_id_;

  const TupleDescriptor* tuple_desc_;

  std::vector<SlotDescriptor*> materialized_slots_;

  std::vector<std::vector<ExprContext*> > const_result_expr_ctx_lists_;

  int const_result_expr_idx_;

  std::vector<std::vector<ExprContext*> > result_expr_ctx_lists_;

  int child_idx_;

  boost::scoped_ptr<RowBatch> child_row_batch_;

  bool child_eos_;

  int child_row_idx_;

  Status OpenCurrentChild(RuntimeState* state);

  bool EvalAndMaterializeExprs( const std::vector<ExprContext*>& ctxs,
                                bool const_exprs, Tuple** tuple, RowBatch* row_batch);
};

}

#endif