Result: Remove m_has_value, rely on Option::has_value()

luna/include/luna/Option.h

@@ -101,6 +101,14 @@ template <typename T> class Option
         return true;
     }
 
+    bool try_move_value(T& ref) const
+    {
+        if (!has_value()) return false;
+        m_has_value = false;
+        ref = move(m_storage.fetch_reference());
+        return true;
+    }
+
     ~Option()
     {
         if (has_value()) m_storage.destroy();

luna/include/luna/Result.h

@@ -20,24 +20,23 @@ struct Error
 template <typename T> class Result
 {
   public:
-    Result(const T& value) : m_value(value), m_has_value(true)
+    Result(const T& value) : m_value(value)
     {
     }
 
-    Result(T&& value) : m_value(move(value)), m_has_value(true)
+    Result(T&& value) : m_value(move(value))
     {
     }
 
-    Result(const Result<T>& other) : m_value(other.m_value), m_has_value(other.m_has_value), m_error(other.m_error)
+    Result(const Result<T>& other) : m_value(other.m_value), m_error(other.m_error)
     {
     }
 
-    Result(Result<T>&& other) : m_value(move(other.m_value)), m_has_value(other.m_has_value), m_error(other.m_error)
+    Result(Result<T>&& other) : m_value(move(other.m_value)), m_error(other.m_error)
     {
-        other.m_has_value = false;
     }
 
-    Result(const Error& err) : m_value(), m_has_value(false), m_error(err.error)
+    Result(const Error& err) : m_value(), m_error(err.error)
     {
     }
 
@@ -45,7 +44,6 @@ template <typename T> class Result
     {
         if (this == &other) return *this;
 
-        m_has_value = other.m_has_value;
         m_error = other.m_error;
         m_value = other.m_value;
 
@@ -56,8 +54,6 @@ template <typename T> class Result
     {
         if (this == &other) return *this;
 
-        m_has_value = other.m_has_value;
-        other.m_has_value = false;
         m_error = other.m_error;
         m_value = move(other.m_value);
 
@@ -66,12 +62,12 @@ template <typename T> class Result
 
     bool has_error() const
     {
-        return !m_has_value;
+        return !m_value.has_value();
     }
 
     bool has_value() const
     {
-        return m_has_value;
+        return m_value.has_value();
     }
 
     int error() const
@@ -114,6 +110,12 @@ template <typename T> class Result
         return m_value.try_set_value(ref);
     }
 
+    bool try_move_value(T& ref) const
+    {
+        return m_value.try_move_value(ref);
+    }
+
+    // FIXME: Please remove this.
     Result<bool> try_set_value_with_specific_error(T& ref, int error)
     {
         if (has_error() && m_error != error) return release_error();
@@ -135,7 +137,6 @@ template <typename T> class Result
 
   private:
     Option<T> m_value;
-    bool m_has_value;
     int m_error;
 };