Ensure argument transparency.

ThePhD · Apr 18, 2016 · 96da27d · 96da27d
1 parent 062d228
commit 96da27d
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Showing 5 changed files with 30 additions and 11 deletions.
diff --git a/sol/stack.hpp b/sol/stack.hpp
@@ -76,18 +76,18 @@ inline std::pair<T, int> get_as_upvalues(lua_State* L, int index = 1) {
 
 template <bool checkargs = default_check_arguments, std::size_t... I, typename R, typename... Args, typename Fx, typename... FxArgs, typename = std::enable_if_t<!std::is_void<R>::value>>
 inline decltype(auto) call(types<R>, types<Args...> ta, std::index_sequence<I...> tai, lua_State* L, int start, Fx&& fx, FxArgs&&... args) {
-    typedef meta::index_in_pack<this_state, Args...> state_pack_index;
-    typedef std::integral_constant<int, state_pack_index::value == -1 ? INT_MAX : static_cast<int>(state_pack_index::value)> state_idx;
+    typedef meta::index_in_pack<this_state, Args...> state_index;
+    typedef meta::index_in_pack<variadic_args, Args...> va_pack_index;
     check_types<checkargs>{}.check(ta, tai, L, start, type_panic);
-    return fx(std::forward<FxArgs>(args)..., stack_detail::unchecked_get<Args>(L, start + (state_idx::value < I ? I - 1 : I))...);
+    return fx(std::forward<FxArgs>(args)..., stack_detail::unchecked_get<Args>(L, start + I - static_cast<int>(state_index::value < I) - static_cast<int>(va_pack_index::value < I))...);
 }
 
 template <bool checkargs = default_check_arguments, std::size_t... I, typename... Args, typename Fx, typename... FxArgs>
 inline void call(types<void>, types<Args...> ta, std::index_sequence<I...> tai, lua_State* L, int start, Fx&& fx, FxArgs&&... args) {
-    typedef meta::index_in_pack<this_state, Args...> state_pack_index;
-    typedef std::integral_constant<int, state_pack_index::value == -1 ? INT_MAX : static_cast<int>(state_pack_index::value)> state_idx;
+    typedef meta::index_in_pack<this_state, Args...> state_index;
+    typedef meta::index_in_pack<variadic_args, Args...> va_pack_index;
     check_types<checkargs>{}.check(ta, tai, L, start, type_panic);
-    fx(std::forward<FxArgs>(args)..., stack_detail::unchecked_get<Args>(L, start + (state_idx::value < I ? I - 1 : I))...);
+    fx(std::forward<FxArgs>(args)..., stack_detail::unchecked_get<Args>(L, start + I - static_cast<int>(state_index::value < I) - static_cast<int>(va_pack_index::value < I))...);
 }
 } // stack_detail
 

diff --git a/sol/stack_check.hpp b/sol/stack_check.hpp
@@ -61,11 +61,11 @@ struct basic_check {
 
 template <bool b>
 struct check_types {
-    template <std::size_t I0, std::size_t... I, typename Arg0, typename... Args, typename Handler>
-    static bool check(types<Arg0, Args...>, std::index_sequence<I0, I...>, lua_State* L, int firstargument, Handler&& handler) {
-        if (!stack::check<Arg0>(L, firstargument + I0, handler))
+    template <std::size_t I0, std::size_t... I, typename T, typename... Args, typename Handler>
+    static bool check(types<T, Args...>, std::index_sequence<I0, I...>, lua_State* L, int firstargument, Handler&& handler) {
+        if (!stack::check<T>(L, firstargument + I0, handler))
             return false;
-        return check(types<Args...>(), std::index_sequence<I...>(), L, firstargument - static_cast<int>(std::is_same<this_state, meta::Unqualified<Arg0>>::value), std::forward<Handler>(handler));
+        return check(types<Args...>(), std::index_sequence<I...>(), L, firstargument - static_cast<int>(is_transparent_argument<meta::Unqualified<T>>::value), std::forward<Handler>(handler));
     }
 
     template <typename Handler>

diff --git a/sol/traits.hpp b/sol/traits.hpp
@@ -134,7 +134,7 @@ struct find_in_pack_v<V, Vs1, Vs...> : Or<Bool<(V::value == Vs1::value)>, find_i
 
 namespace meta_detail {
     template<std::size_t I, typename T, typename... Args>
-    struct index_in_pack : std::integral_constant<std::ptrdiff_t, -1> { };
+    struct index_in_pack : std::integral_constant<std::size_t, SIZE_MAX> { };
 
     template<std::size_t I, typename T, typename T1, typename... Args>
     struct index_in_pack<I, T, T1, Args...> : std::conditional_t<std::is_same<T, T1>::value, std::integral_constant<std::ptrdiff_t, I>, index_in_pack<I + 1, T, Args...>> { };

diff --git a/sol/types.hpp b/sol/types.hpp
@@ -315,6 +315,8 @@ using lightuserdata = basic_lightuserdata<reference>;
 using stack_lightuserdata = basic_lightuserdata<stack_reference>;
 class coroutine;
 class thread;
+struct variadic_args;
+struct this_state;
 
 template <typename T, typename = void>
 struct lua_type_of : std::integral_constant<type, type::userdata> {};
@@ -434,6 +436,15 @@ struct is_proxy_primitive : is_lua_primitive<T> { };
 template <typename T>
 struct is_unique_usertype : std::false_type {};
 
+template <typename T>
+struct is_transparent_argument : std::false_type {};
+
+template <>
+struct is_transparent_argument<this_state> : std::true_type {};
+
+template <>
+struct is_transparent_argument<variadic_args> : std::true_type {};
+
 template<typename T>
 inline type type_of() {
     return lua_type_of<meta::Unqualified<T>>::value;

diff --git a/test_functions.cpp b/test_functions.cpp
@@ -781,3 +781,11 @@ TEST_CASE("functions/variadic_args", "Check to see we can receive multiple argum
     REQUIRE(lx2.b);
     REQUIRE_FALSE(lx3.b);
 }
+
+TEST_CASE("functions/required_and_variadic_args", "Check if a certain number of arguments can still be required even when using variadic_args") {
+    sol::state lua;
+    lua.set_function("v", [](sol::this_state, sol::variadic_args, int, int) {});
+    REQUIRE_NOTHROW(lua.script("v(20, 25, 30)"));
+    REQUIRE_NOTHROW(lua.script("v(20, 25)"));
+    REQUIRE_THROWS(lua.script("v(20)"));
+}