From 6af50414c3a6f1e28372eaabb12d66d67c645db3 Mon Sep 17 00:00:00 2001
From: fleroviux <fleroviux@gmail.com>
Date: Mon, 8 Jul 2024 23:21:33 +0200
Subject: [PATCH] Zephyr: Common: make Result<T,U> movable

---
 zephyr/common/include/zephyr/result.hpp | 25 +++++++++++++++++++++++++
 1 file changed, 25 insertions(+)

diff --git a/zephyr/common/include/zephyr/result.hpp b/zephyr/common/include/zephyr/result.hpp
index dad8108..d532be8 100644
--- a/zephyr/common/include/zephyr/result.hpp
+++ b/zephyr/common/include/zephyr/result.hpp
@@ -2,6 +2,7 @@
 #pragma once
 
 #include <zephyr/panic.hpp>
+#include <algorithm>
 #include <memory>
 #include <type_traits>
 
@@ -10,6 +11,13 @@ namespace zephyr {
   #define ZEPHYR_RESULT_EMPTY (-1)
   #define ZEPHYR_RESULT_SUCCESS 0
 
+  #define ZEPHYR_FORWARD_ERROR(result) do { \
+    const auto status_code = (result).Code(); \
+    if(status_code != ZEPHYR_RESULT_SUCCESS) { \
+      return status_code;\
+    } \
+  } while(0)
+
   template<typename StatusCode, typename T>
     requires std::is_move_constructible_v<T>
   class Result {
@@ -20,6 +28,12 @@ namespace zephyr {
 
       Result(T&& value) : m_status_code{(StatusCode)ZEPHYR_RESULT_SUCCESS}, m_value{std::move(value)} {}
 
+      Result(const Result&) = delete;
+
+      Result(Result&& other_result) {
+        operator=(other_result);
+      }
+
      ~Result() { // needed if `T` has a non-trivial destructor since m_value is in a union
         if(Ok()) {
           m_value.~T();
@@ -50,6 +64,17 @@ namespace zephyr {
         return std::move(m_value);
       }
 
+      Result& operator=(const Result&) = delete;
+
+      Result& operator=(Result&& other_result) noexcept {
+        std::swap(m_status_code, other_result.m_status_code);
+
+        // As per C++11 standard a union member can only be initialized either during
+        // initialization of the union or via placement-new. See: https://stackoverflow.com/a/33058919
+        new (&m_value) T(std::move(other_result.m_value));
+        return *this;
+      }
+
     private:
       StatusCode m_status_code{};
       union { // Union used to avoid default initialization