posix/interface: move data holding into the container

posix/interface.hpp

@@ -19,13 +19,8 @@ namespace cruft::posix {
     interface (void)
     {
         struct iterator {
-            iterator ()
+            explicit iterator (ifaddrs *_cursor) noexcept
-            {
+              : cursor (_cursor)
-                error::try_call (getifaddrs, &cursor);
-            }
-
-            iterator (ifaddrs *_cursor):
-                cursor (_cursor)
             { ; }
 
             ifaddrs *cursor;
@@ -44,9 +39,37 @@ namespace cruft::posix {
         };
 
 
-        struct container {
+        class container {
-            auto begin (void) { return iterator (       ); }
+        public:
+            container ()
+            {
+                error::try_call (getifaddrs, &m_data);
+            }
+
+            ~container ()
+            {
+                if (m_data)
+                    freeifaddrs (m_data);
+            }
+
+
+            container (container &&rhs) noexcept:
+                m_data (std::exchange (rhs.m_data, nullptr))
+            { ; }
+
+            container& operator= (container &&rhs) noexcept
+            {
+                std::swap (m_data, rhs.m_data);
+                return *this;
+            }
+
+            container (container const&) = delete;
+            container& operator= (container const&) = delete;
+
+            auto begin (void) { return iterator (m_data); }
             auto end   (void) { return iterator (nullptr); }
+
+            ifaddrs *m_data;
         };
 
         return container ();