be/src/exprs/cast-format-expr.h

// Licensed to the Apache Software Foundation (ASF) under one
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// distributed with this work for additional information
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// to you under the Apache License, Version 2.0 (the
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// with the License.  You may obtain a copy of the License at
//
//   http://www.apache.org/licenses/LICENSE-2.0
//
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// software distributed under the License is distributed on an
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#pragma once

#include "exprs/scalar-fn-call.h"
#include "runtime/datetime-parser-common.h"
#include <string>

namespace impala {

/// This is a wrapper class around ScalarFnCall to store additional information specific
/// to the cast() operator.
class CastFormatExpr : public ScalarFnCall {
public:
  /// Note, that it should be verified at the callsite that TExprNode.cast_expr is set.
  CastFormatExpr(const TExprNode& node)
      : ScalarFnCall(node), format_(node.cast_expr.cast_format) {}

  /// Saves 'format_' into the FunctionContext object within the ScalarExprEvaluator.
  Status OpenEvaluator(FunctionContext::FunctionStateScope scope, RuntimeState* state,
      ScalarExprEvaluator* eval) const override WARN_UNUSED_RESULT;
  void CloseEvaluator(FunctionContext::FunctionStateScope scope, RuntimeState* state,
      ScalarExprEvaluator* eval) const override;
private:
  std::string format_;
  /// Keeps track of the DateTimeFormatContext put into FunctionContext in
  /// OpenEvaluator().
  /// This is empty in case of FunctionContext::THREAD_LOCAL.
  mutable std::unique_ptr<datetime_parse_util::DateTimeFormatContext> dt_ctx_;

  datetime_parse_util::CastDirection GetCastMode(const FunctionContext* ctx) const;
};

}