scalar-fn-call.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_EXPRS_SCALAR_FN_CALL_H_
#define IMPALA_EXPRS_SCALAR_FN_CALL_H_

#include <string>

#include "exprs/expr.h"
#include "udf/udf.h"

using namespace impala_udf;

namespace impala {

class TExprNode;

//
//
class ScalarFnCall: public Expr {
 public:
  virtual std::string DebugString() const;

 protected:
  friend class Expr;

  ScalarFnCall(const TExprNode& node);
  virtual Status Prepare(RuntimeState* state, const RowDescriptor& desc,
                         ExprContext* context);
  virtual Status Open(RuntimeState* state, ExprContext* context,
      FunctionContext::FunctionStateScope scope = FunctionContext::FRAGMENT_LOCAL);
  virtual Status GetCodegendComputeFn(RuntimeState* state, llvm::Function** fn);
  virtual void Close(RuntimeState* state, ExprContext* context,
      FunctionContext::FunctionStateScope scope = FunctionContext::FRAGMENT_LOCAL);

  virtual bool IsConstant() const;

  virtual BooleanVal GetBooleanVal(ExprContext* context, TupleRow*);
  virtual TinyIntVal GetTinyIntVal(ExprContext* context, TupleRow*);
  virtual SmallIntVal GetSmallIntVal(ExprContext* context, TupleRow*);
  virtual IntVal GetIntVal(ExprContext* context, TupleRow*);
  virtual BigIntVal GetBigIntVal(ExprContext* context, TupleRow*);
  virtual FloatVal GetFloatVal(ExprContext* context, TupleRow*);
  virtual DoubleVal GetDoubleVal(ExprContext* context, TupleRow*);
  virtual StringVal GetStringVal(ExprContext* context, TupleRow*);
  virtual TimestampVal GetTimestampVal(ExprContext* context, TupleRow*);
  virtual DecimalVal GetDecimalVal(ExprContext* context, TupleRow*);

 private:
  int vararg_start_idx_;

  void* scalar_fn_wrapper_;

  UdfPrepare prepare_fn_;

  UdfClose close_fn_;

  void* scalar_fn_;

  int NumFixedArgs() const {
    return vararg_start_idx_ >= 0 ? vararg_start_idx_ : children_.size();
  }

  Status GetUdf(RuntimeState* state, llvm::Function** udf);

  Status GetFunction(RuntimeState* state, const std::string& symbol, void** fn);

  void EvaluateChildren(ExprContext* context, TupleRow* row,
                        std::vector<impala_udf::AnyVal*>* input_vals);

  template<typename RETURN_TYPE>
  RETURN_TYPE InterpretEval(ExprContext* context, TupleRow* row);
};

}

#endif