stages.hpp

#ifndef SRC_COMMON_PIPELINE_STAGES_HPP_
#define SRC_COMMON_PIPELINE_STAGES_HPP_
 
#include <type_traits>
 
namespace found {
 
template<typename T>
using raw_type = std::remove_cv_t<std::remove_reference_t<T>>;
 
class Action {
 public:
    virtual ~Action() = default;
    virtual void DoAction() = 0;
};
 
template<typename Input, typename Output>
class Stage : public Action {
 public:
    virtual Output Run(Input input) = 0;
};
 
template<typename Input, typename Output>
class FunctionStage : public Stage<const raw_type<Input> &, raw_type<Output>> {
 public:
    FunctionStage() = default;
 
    virtual ~FunctionStage() = default;
 
    void DoAction() override {
      *this->product = this->Run(this->resource);
    };
 
    Input &GetResource() {return resource;}
 
    Output *&GetProduct() {return product;}
 
 protected:
    Input resource;
    Output *product = nullptr;
};
 
template<typename T>
class ModifyingStage : public Stage<raw_type<T> &, void> {
 public:
    ModifyingStage() = default;
 
    virtual ~ModifyingStage() = default;
 
    void DoAction() override {
        this->Run(*this->resource);
    };
 
    void SetResource(T &resource) {this->resource = &resource;}
 
 private:
    T *resource = nullptr;
};
 
}  // namespace found
 
 
#endif  // SRC_COMMON_PIPELINE_STAGES_HPP_