Factory fucntion make_unique_resource_checked() added.

include/unique_resource.h

@@ -199,6 +199,7 @@ namespace sr
     };
 
 
+
     template<class R, class D>
     unique_resource<std::decay_t<R>, std::decay_t<D>> make_unique_resource(R&& r, D&& d)
                                                             noexcept(std::is_nothrow_constructible<std::decay_t<R>, R>::value
@@ -209,11 +210,27 @@ namespace sr
 
     template<class R, class D>
     unique_resource<R&, std::decay_t<D>> make_unique_resource(std::reference_wrapper<R> r, D d)
-                                            noexcept(std::is_nothrow_constructible<std::decay_t<D>, D>::value)
+                                                noexcept(std::is_nothrow_constructible<std::decay_t<D>, D>::value)
     {
         return unique_resource<R&, std::decay_t<D>>(r.get(), std::forward<D>(d));
     }
 
+    template<class R, class D, class S = R>
+    unique_resource<std::decay_t<R>, std::decay_t<D>> make_unique_resource_checked(R&& r, const S& invalid, D&& d)
+                                                            noexcept(std::is_nothrow_constructible<std::decay_t<R>, R>::value
+                                                                    && std::is_nothrow_constructible<std::decay_t<D>, D>::value)
+    {
+        const bool mustRelease{r == invalid};
+        auto ur = make_unique_resource(r, d);
+
+        if( mustRelease == true )
+        {
+            ur.release();
+        }
+
+        return ur;
+    }
+
 }
 
 

test/UniqueResourceTest.cpp

@@ -273,3 +273,16 @@ TEST_CASE("make unique resource with reference wrapper", "[UniqueResource]")
     static_cast<void>(guard);
 }
 
+TEST_CASE("make unique resource checked", "[UniqueResource]")
+{
+    REQUIRE_CALL(m, deleter(4));
+    auto guard = sr::make_unique_resource_checked(Handle{4}, Handle{-1}, deleter);
+    static_cast<void>(guard);
+}
+
+TEST_CASE("make unique resource checked releases if invalid", "[UniqueResource]")
+{
+    auto guard = sr::make_unique_resource_checked(Handle{-1}, Handle{-1}, deleter);
+    static_cast<void>(guard);
+}
+