guard_condition.hpp

Go to the documentation of this file.

// nros-cpp: Guard condition class
// Freestanding C++ — no exceptions, no STL required
 
#ifndef NROS_CPP_GUARD_CONDITION_HPP
#define NROS_CPP_GUARD_CONDITION_HPP
 
#include <cstdint>
#include <cstddef>
 
#include "nros/config.hpp"
#include "nros/result.hpp"
 
#ifdef NROS_CPP_STD
#include <functional>
#include <memory>
#endif
 
#include "nros_cpp_ffi.h"
 
namespace nros {
 
class GuardCondition {
  public:
    Result trigger() {
        if (!initialized_) return Result(ErrorCode::NotInitialized);
        return Result(nros_cpp_guard_condition_trigger(storage_));
    }
 
    bool is_valid() const { return initialized_; }
 
    ~GuardCondition() {
        if (initialized_) {
            nros_cpp_guard_condition_destroy(storage_);
            initialized_ = false;
        }
        // closure_ (if any) destructs here.
    }
 
    // Move semantics (non-copyable). Relocation goes through the
    // `nros_cpp_guard_condition_relocate` runtime call (Phase 84.C1).
    GuardCondition(GuardCondition&& other)
        : initialized_(other.initialized_)
#ifdef NROS_CPP_STD
          ,
          closure_(std::move(other.closure_))
#endif
    {
        if (other.initialized_) {
            nros_cpp_guard_condition_relocate(other.storage_, storage_);
            other.initialized_ = false;
        }
    }
 
    GuardCondition& operator=(GuardCondition&& other) {
        if (this != &other) {
            if (initialized_) {
                nros_cpp_guard_condition_destroy(storage_);
                initialized_ = false;
            }
            if (other.initialized_) {
                nros_cpp_guard_condition_relocate(other.storage_, storage_);
                initialized_ = true;
                other.initialized_ = false;
            }
#ifdef NROS_CPP_STD
            closure_ = std::move(other.closure_);
#endif
        }
        return *this;
    }
 
    GuardCondition() : storage_(), initialized_(false) {}
 
#ifdef NROS_CPP_STD
    void attach_std_closure(std::unique_ptr<std::function<void()>> closure) {
        closure_ = std::move(closure);
    }
#endif
 
  private:
    GuardCondition(const GuardCondition&) = delete;
    GuardCondition& operator=(const GuardCondition&) = delete;
 
    friend class Node;
 
    alignas(8) uint8_t storage_[NROS_GUARD_CONDITION_SIZE];
    bool initialized_;
 
#ifdef NROS_CPP_STD
    std::unique_ptr<std::function<void()>> closure_;
#endif
};
 
} // namespace nros
 
#endif // NROS_CPP_GUARD_CONDITION_HPP