cpp/src/gandiva/expr_validator.h

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#ifndef GANDIVA_EXPR_VALIDATOR_H
#define GANDIVA_EXPR_VALIDATOR_H

#include <string>
#include <unordered_map>

#include "arrow/status.h"
#include "boost/functional/hash.hpp"

#include "gandiva/arrow.h"
#include "gandiva/expression.h"
#include "gandiva/function_registry.h"
#include "gandiva/llvm_types.h"
#include "gandiva/node.h"
#include "gandiva/node_visitor.h"

namespace gandiva {

class FunctionRegistry;

/// \brief Validates the entire expression tree including
/// data types, signatures and return types
class ExprValidator : public NodeVisitor {
 public:
  explicit ExprValidator(LLVMTypes* types, SchemaPtr schema)
      : types_(types), schema_(schema) {
    for (auto& field : schema_->fields()) {
      field_map_[field->name()] = field;
    }
  }

  /// \brief Validates the root node
  /// of an expression.
  /// 1. Data type of fields and literals.
  /// 2. Function signature is supported.
  /// 3. For if nodes that return types match
  ///    for if, then and else nodes.
  Status Validate(const ExpressionPtr& expr);

 private:
  Status Visit(const FieldNode& node) override;
  Status Visit(const FunctionNode& node) override;
  Status Visit(const IfNode& node) override;
  Status Visit(const LiteralNode& node) override;
  Status Visit(const BooleanNode& node) override;
  Status Visit(const InExpressionNode<int32_t>& node) override;
  Status Visit(const InExpressionNode<int64_t>& node) override;
  Status Visit(const InExpressionNode<std::string>& node) override;
  Status ValidateInExpression(size_t number_of_values, DataTypePtr in_expr_return_type,
                              DataTypePtr type_of_values);

  FunctionRegistry registry_;

  LLVMTypes* types_;

  SchemaPtr schema_;

  using FieldMap = std::unordered_map<std::string, FieldPtr, boost::hash<std::string>>;
  FieldMap field_map_;
};

}  // namespace gandiva

#endif  // GANDIVA_EXPR_VALIDATOR_H