evaluation_stack.hpp

#pragma once
 
#include <optional>
#include <string>
#include <unordered_set>
 
namespace launchdarkly::server_side::evaluation {
 
struct Guard {
    Guard(std::unordered_set<std::string>& set, std::string key);
    ~Guard();
 
    Guard(Guard const&) = delete;
    Guard& operator=(Guard const&) = delete;
 
    Guard(Guard&&) = delete;
    Guard& operator=(Guard&&) = delete;
 
   private:
    std::unordered_set<std::string>& set_;
    std::string const key_;
};
 
class EvaluationStack {
   public:
    EvaluationStack() = default;
 
    [[nodiscard]] std::optional<Guard> NoticePrerequisite(
        std::string prerequisite_key);
 
    [[nodiscard]] std::optional<Guard> NoticeSegment(std::string segment_key);
 
   private:
    std::unordered_set<std::string> prerequisites_seen_;
    std::unordered_set<std::string> segments_seen_;
};
 
}  // namespace launchdarkly::server_side::evaluation