validator.hpp

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#pragma once
 
/// @file userver/formats/json/parser/validator.hpp
/// @brief Lightweight validators for parsed JSON values.
/// @ingroup userver_universal
 
#include <utility>
 
USERVER_NAMESPACE_BEGIN
 
namespace formats::json::parser {
 
template <typename T>
class BaseValidator {
public:
    virtual void operator()(const T& t) const = 0;
};
 
template <typename T, typename F>
class Validator final : public BaseValidator<T> {
public:
    explicit Validator(F f)
        : f_(std::move(f))
    {}
 
    void operator()(const T& t) const override { f_(t); }
 
private:
    F f_;
};
 
template <typename T>
class EmptyValidator final : public BaseValidator<T> {
public:
    void operator()(const T&) const override {}
};
 
template <typename T, typename F>
auto MakeValidator(F f) {
    return Validator<T, F>(std::move(f));
}
 
template <typename T>
inline constexpr EmptyValidator<T> kEmptyValidator;
 
}  // namespace formats::json::parser
 
USERVER_NAMESPACE_END