From b66c7f015ad4dbba2c4fba9b3c6414012df64236 Mon Sep 17 00:00:00 2001
From: ThePhD <phdofthehouse@gmail.com>
Date: Mon, 1 Feb 2016 11:56:44 -0500
Subject: [PATCH] Significant change to how userdata is stored to make access
 consistent across values/references/pointers.

---
 sol/function.hpp       |  4 +--
 sol/function_types.hpp |  2 +-
 sol/stack.hpp          | 62 +++++++++++++++++++------------------
 sol/state_view.hpp     |  4 +--
 sol/table_core.hpp     | 69 ++++++++++++++++++++++++------------------
 sol/traits.hpp         |  3 ++
 sol/usertype.hpp       | 10 ++++--
 tests.cpp              | 30 +++++++++++++-----
 8 files changed, 110 insertions(+), 74 deletions(-)

diff --git a/sol/function.hpp b/sol/function.hpp
index 4c93be9e..57831171 100644
--- a/sol/function.hpp
+++ b/sol/function.hpp
@@ -66,8 +66,8 @@ private:
         int stacksize = lua_gettop( lua_state( ) );
         int firstreturn = std::max( 1, stacksize - static_cast<int>( n ) );
         luacall( n, LUA_MULTRET );
-	   int poststacksize = lua_gettop( lua_state( ) );
-	   int returncount = poststacksize - firstreturn;
+        int poststacksize = lua_gettop( lua_state( ) );
+        int returncount = poststacksize - firstreturn;
         return function_result( lua_state( ), firstreturn, returncount, returncount, call_error::ok );
     }
 
diff --git a/sol/function_types.hpp b/sol/function_types.hpp
index f9b6a69c..1490a60e 100644
--- a/sol/function_types.hpp
+++ b/sol/function_types.hpp
@@ -278,7 +278,7 @@ struct base_function {
     struct usertype {
         static int call(lua_State* L) {
             // Zero-based template parameter, but upvalues start at 1
-            return base_call(L, stack::get<upvalue>(L, I + 1));
+            return ref_base_call(L, stack::get<upvalue>(L, I + 1));
         }
 
         static int ref_call(lua_State* L) {
diff --git a/sol/stack.hpp b/sol/stack.hpp
index c4bca4b6..10366409 100644
--- a/sol/stack.hpp
+++ b/sol/stack.hpp
@@ -133,36 +133,42 @@ true;
 false;
 #endif
 
-inline void lua_getglobali(lua_State* L, lua_Integer n) {
-#if SOL_LUA_VERSION >= 503
-    lua_geti(L, LUA_RIDX_GLOBALS, n);
-#else
-    lua_pushglobaltable(L);
-    lua_pushinteger(L, n);
-    lua_gettable(L, -2);
-    lua_remove(L, -2); // remove the global table, leave final value on the stack
-#endif
-}
+template <typename T>
+struct userdata_pusher {
+    template <typename Key, typename... Args>
+    static void push (lua_State* L, Key&& metatablekey, Args&&... args) {
+        // Basically, we store all data like this:
+        // If it's a new value (no std::ref(x)), then we store the pointer to the new
+        // data in the first sizeof(T*) bytes, and then however many bytes it takes to
+        // do the actual object. Things that are just references/pointers are stored as 
+        // just the sizeof(T*), and nothing else.
+        T** pdatum = static_cast<T**>(lua_newuserdata(L, sizeof(T*) + sizeof(T)));
+        T** referencepointer = pdatum;
+        T*& referencereference = *pdatum;
+        T* allocationtarget = reinterpret_cast<T*>(pdatum + 1);
+        referencereference = allocationtarget;
+        std::allocator<T> alloc{};
+        alloc.construct(allocationtarget, std::forward<Args>(args)...);
+        luaL_getmetatable(L, std::addressof(metatablekey[0]));
+        lua_setmetatable(L, -2);
+    }
+};
 
-inline void lua_setglobali(lua_State* L, lua_Integer n) {
-#if SOL_LUA_VERSION >= 503
-    lua_seti(L, LUA_RIDX_GLOBALS, n);
-#else
-    lua_pushglobaltable(L);
-    lua_pushinteger(L, n);
-    lua_pushvalue(L, -3);
-    lua_settable(L, -3);
-    lua_pop(L, 2); // remove table, and the copy of the value
-#endif
-}
+template <typename T>
+struct userdata_pusher<T*> {
+    template <typename Key, typename... Args>
+    static void push (lua_State* L, Key&& metatablekey, Args&&... args) {
+        T** pdatum = static_cast<T**>(lua_newuserdata(L, sizeof(T*)));
+        std::allocator<T*> alloc{};
+        alloc.construct(pdatum, std::forward<Args>(args)...);
+        luaL_getmetatable(L, std::addressof(metatablekey[0]));
+        lua_setmetatable(L, -2);
+    }
+};
 
 template <typename T, typename Key, typename... Args>
 inline int push_confirmed_userdata(lua_State* L, Key&& metatablekey, Args&&... args) {
-    T* pdatum = static_cast<T*>(lua_newuserdata(L, sizeof(T)));
-    std::allocator<T> alloc{};
-    alloc.construct(pdatum, std::forward<Args>(args)...);
-    luaL_getmetatable(L, std::addressof(metatablekey[0]));
-    lua_setmetatable(L, -2);
+    userdata_pusher<T>{}.push(L, std::forward<Key>(metatablekey), std::forward<Args>(args)...);
     return 1;
 }
 
@@ -253,9 +259,7 @@ struct getter {
 
     template<typename U = T, EnableIf<Not<std::is_base_of<reference, U>>, Not<std::is_integral<U>>, Not<std::is_floating_point<U>>> = 0>
     static U& get(lua_State* L, int index = -1) {
-        void* udata = lua_touserdata(L, index);
-        T* obj = static_cast<T*>(udata);
-        return *obj;
+        return getter<T&>{}.get(L, index);
     }
 };
 
diff --git a/sol/state_view.hpp b/sol/state_view.hpp
index 0a6827e6..d2d54003 100644
--- a/sol/state_view.hpp
+++ b/sol/state_view.hpp
@@ -218,8 +218,8 @@ public:
     table create_table(int narr = 0, int nrec = sizeof...(Tn), Tn&&... argn) {
         lua_createtable(L, narr, nrec);
         table result(L);
-	   result.set(std::forward<Tn>(argn)...);
-	   lua_pop(L, 1);
+        result.set(std::forward<Tn>(argn)...);
+        lua_pop(L, 1);
         return result;
     }
 
diff --git a/sol/table_core.hpp b/sol/table_core.hpp
index da0bd50b..a79e65e1 100644
--- a/sol/table_core.hpp
+++ b/sol/table_core.hpp
@@ -37,19 +37,20 @@ class table_core : public reference {
     friend class state;
     friend class state_view;
 
-    template<typename T, typename Key, EnableIf<Not<std::is_integral<Unqualified<Key>>>, Bool<top_level>> = 0>
+    template<typename T, typename Key, EnableIf<Bool<top_level>, is_c_str<Key>> = 0>
     decltype(auto) single_get( Key&& key ) const {
         lua_getglobal(lua_state( ), &key[0]);
         return stack::pop<T>(lua_state());
     }
 
-    template<typename T, typename Key, EnableIf<std::is_integral<Unqualified<Key>>, Bool<top_level>> = 0>
-    decltype(auto) single_get(Key&& key) const {
-        stack::detail::lua_getglobali(lua_state(), &key[0]);
-        return stack::pop<T>(lua_state());
+    template<typename T, typename Key, EnableIf<Not<Bool<top_level>>, is_c_str<Key>> = 0>
+    decltype(auto) single_get( Key&& key ) const {
+        auto pp = stack::push_popper(*this);
+        lua_getfield( lua_state( ), -2, &key[0] );
+        return stack::pop<T>( lua_state( ) );
     }
 
-    template<typename T, typename Key, DisableIf<Bool<top_level>, Not<std::is_void<Key>>> = 0>
+    template<typename T, typename Key, EnableIf<Not<is_c_str<Key>>> = 0>
     decltype(auto) single_get( Key&& key ) const {
         auto pp = stack::push_popper(*this);
         stack::push( lua_state( ), std::forward<Key>( key ) );
@@ -57,6 +58,27 @@ class table_core : public reference {
         return stack::pop<T>( lua_state( ) );
     }
 
+    template<typename Key, typename Value, EnableIf<Bool<top_level>, is_c_str<Key>> = 0>
+    void single_set( Key&& key, Value&& value ) {
+        stack::push( lua_state( ), std::forward<Value>( value ) );
+        lua_setglobal( lua_state( ), &key[0] );
+    }
+
+    template<typename Key, typename Value, EnableIf<Not<Bool<top_level>>, is_c_str<Key>> = 0>
+    void single_set(Key&& key, Value&& value) {
+        auto pp = stack::push_popper(*this);
+        stack::push(lua_state(), std::forward<Value>(value));
+        lua_setfield(lua_state(), -3, &key[0]);
+    }
+
+    template<typename Key, typename Value, EnableIf<Not<is_c_str<Key>>> = 0>
+    void single_set(Key&& key, Value&& value) {
+        auto pp = stack::push_popper(*this);
+        stack::push(lua_state(), std::forward<Key>(key));
+        stack::push(lua_state(), std::forward<Value>(value));
+        lua_settable(lua_state(), -3);
+    }
+
     template<typename Keys, typename... Ret, std::size_t... I>
     stack::get_return<Ret...> tuple_get( types<Ret...>, indices<I...>, Keys&& keys ) const {
         return stack::get_return<Ret...>( single_get<Ret>( std::get<I>( keys ) )... );
@@ -67,26 +89,6 @@ class table_core : public reference {
         return single_get<Ret>( std::get<I>( keys ) );
     }
 
-    template<typename Key, typename U, EnableIf<std::is_integral<Unqualified<Key>>, Bool<top_level>> = 0>
-    void single_set( Key&& key, U&& value ) {
-        stack::push( lua_state( ), std::forward<Value>( value ) );
-        stack::detail::lua_setglobali( lua_state( ), std::forward<Key>(key) );
-    }
-
-    template<typename Key, typename Value, EnableIf<Not<std::is_integral<Unqualified<Key>>>, Bool<top_level>> = 0>
-    void single_set( Key&& key, Value&& value ) {
-        stack::push( lua_state( ), std::forward<Value>( value ) );
-        lua_setglobal( lua_state( ), &key[0] );
-    }
-
-    template<typename Key, typename Value, DisableIf<Bool<top_level>, Not<std::is_void<Key>>> = 0>
-    void single_set(Key&& key, Value&& value) {
-        auto pp = stack::push_popper(*this);
-        stack::push(lua_state(), std::forward<Key>(key));
-        stack::push(lua_state(), std::forward<Value>(value));
-        lua_settable(lua_state(), -3);
-    }
-
     template<typename Pairs, std::size_t... I>
     void tuple_set( indices<I...>, Pairs&& pairs ) {
         using swallow = int[];
@@ -113,7 +115,7 @@ public:
     template<typename... Tn>
     table_core& set( Tn&&... argn ) {
         tuple_set(build_indices<sizeof...(Tn) / 2>(), std::forward_as_tuple(std::forward<Tn>(argn)...));
-	   return *this;
+        return *this;
     }
 
     template<typename T>
@@ -225,19 +227,28 @@ private:
         set_fx( types<function_signature_t<Sig>>( ), std::forward<Key>( key ), std::forward<Fx>( fx ) );
     }
 
-    template<typename... Sig, typename... Args, typename Key, EnableIf<Not<std::is_arithmetic<Unqualified<Key>>>, Bool<top_level>> = 0>
+    template<typename... Sig, typename... Args, typename Key, EnableIf<Bool<top_level>, is_c_str<Key>> = 0>
     void set_resolved_function( Key&& key, Args&&... args ) {
         stack::push<function_sig_t<Sig...>>( lua_state( ), std::forward<Args>( args )... );
         lua_setglobal( lua_state( ), &key[ 0 ] );
     }
 
-    template<typename... Sig, typename... Args, typename Key, DisableIf<Not<std::is_arithmetic<Unqualified<Key>>>, Bool<top_level>> = 0>
+    template<typename... Sig, typename... Args, typename Key, EnableIf<Not<Bool<top_level>>, is_c_str<Key>> = 0>
     void set_resolved_function( Key&& key, Args&&... args ) {
         auto pp = stack::push_popper( *this );
         int tabletarget = lua_gettop( lua_state( ) );
         stack::push<function_sig_t<Sig...>>( lua_state( ), std::forward<Args>( args )... );
         lua_setfield( lua_state( ), tabletarget, &key[ 0 ] );
     }
+
+    template<typename... Sig, typename... Args, typename Key, EnableIf<Not<is_c_str<Key>>> = 0>
+    void set_resolved_function( Key&& key, Args&&... args ) {
+        auto pp = stack::push_popper( *this );
+        int tabletarget = lua_gettop( lua_state( ) );
+        stack::push(lua_state(), std::forward<Key>(key));
+        stack::push<function_sig_t<Sig...>>( lua_state( ), std::forward<Args>( args )... );
+        lua_settable( lua_state( ), tabletarget );
+    }
 };
 } // sol
 
diff --git a/sol/traits.hpp b/sol/traits.hpp
index 2f76540d..5ee5a118 100644
--- a/sol/traits.hpp
+++ b/sol/traits.hpp
@@ -315,6 +315,9 @@ struct has_key_value_pair : decltype(has_key_value_pair_impl::test<T>(0)) {};
 template <typename T>
 using is_string_constructible = Or<std::is_same<Unqualified<T>, const char*>, std::is_same<Unqualified<T>, char>, std::is_same<Unqualified<T>, std::string>, std::is_same<Unqualified<T>, std::initializer_list<char>>>;
 
+template <typename T>
+using is_c_str = Or<std::is_same<std::decay_t<Unqualified<T>>, const char*>, std::is_same<Unqualified<T>, std::string>>;
+
 template<typename T>
 auto unwrapper(T&& item) -> decltype(std::forward<T>(item)) {
     return std::forward<T>(item);
diff --git a/sol/usertype.hpp b/sol/usertype.hpp
index b4098ca7..9344b8a8 100644
--- a/sol/usertype.hpp
+++ b/sol/usertype.hpp
@@ -125,8 +125,10 @@ private:
             call_syntax syntax = stack::get_call_syntax(L, meta);
             int argcount = lua_gettop(L);
 
-            void* udata = lua_newuserdata(L, sizeof(T));
-            T* obj = static_cast<T*>(udata);
+            T** referencepointer = reinterpret_cast<T**>(lua_newuserdata(L, sizeof(T*) + sizeof(T)));
+            T*& referencereference = *referencepointer;
+            T* obj = reinterpret_cast<T*>(referencepointer + 1);
+            referencereference = obj;
             match_constructor(L, obj, syntax, argcount - static_cast<int>(syntax), typename identity<TTypes>::type()...);
 
             if(luaL_newmetatable(L, std::addressof(meta[0])) == 1) {
@@ -144,7 +146,9 @@ private:
     struct destructor {
         static int destruct(lua_State* L) {
             userdata udata = stack::get<userdata>(L, 1);
-            T* obj = static_cast<T*>(udata.value);
+            // The first sizeof(T*) bytes are the reference: the rest is
+            // the actual data itself
+            T* obj = static_cast<T*>(static_cast<void*>(reinterpret_cast<char*>(udata.value) + sizeof(T*)));
             std::allocator<T> alloc{};
             alloc.destroy(obj);
             return 0;
diff --git a/tests.cpp b/tests.cpp
index 5b46a084..570ad6b3 100644
--- a/tests.cpp
+++ b/tests.cpp
@@ -231,6 +231,16 @@ TEST_CASE("simple/get", "Tests if the get function works properly.") {
     REQUIRE(e == true);
 }
 
+TEST_CASE("simple/set-get-global-integer", "Tests if the get function works properly with global integers") {
+    sol::state lua;
+    lua[1] = 25.4;
+    lua.script("b = 1");
+    double a = lua.get<double>(1);
+    double b = lua.get<double>("b");
+    REQUIRE(a == 25.4);
+    REQUIRE(b == 1);
+}
+
 TEST_CASE("simple/addition", "check if addition works and can be gotten through lua.get and lua.set") {
     sol::state lua;
 
@@ -704,7 +714,7 @@ TEST_CASE("tables/usertype utility derived", "usertype classes must play nice wh
     lua.script("base = Base.new(5)");
     REQUIRE_NOTHROW(lua.script("print(base:get_num())"));
 
-    /*sol::constructors<sol::types<int>> derivedctor;
+    sol::constructors<sol::types<int>> derivedctor;
     sol::usertype<Derived> derivedusertype(derivedctor, 
         "get_num_10", &Derived::get_num_10, 
         "get_num", &Derived::get_num
@@ -720,7 +730,7 @@ TEST_CASE("tables/usertype utility derived", "usertype classes must play nice wh
         "print(dgn10)");
 
     REQUIRE((lua.get<int>("dgn10") == 70));
-    REQUIRE((lua.get<int>("dgn") == 7));*/
+    REQUIRE((lua.get<int>("dgn") == 7));
 }
 
 TEST_CASE("tables/self-referential usertype", "usertype classes must play nice when C++ object types are requested for C++ code") {
@@ -1058,10 +1068,10 @@ TEST_CASE("functions/destructor-tests", "Show that proper copies / destruction h
         x() {++created;}
         x(const x&) {++created;}
         x(x&&) {++created;}
-        x& operator=(const x&) {++created; return *this;}
-        x& operator=(x&&) {++created; return *this;}
+        x& operator=(const x&) {return *this;}
+        x& operator=(x&&) {return *this;}
         void func() {last_call = static_cast<void*>(this);};
-       ~x () {++destroyed;} 
+        ~x () {++destroyed;} 
     };
     struct y { 
         y() {++created;}
@@ -1070,8 +1080,8 @@ TEST_CASE("functions/destructor-tests", "Show that proper copies / destruction h
         y& operator=(const x&) {return *this;}
         y& operator=(x&&) {return *this;}
         static void func() {last_call = static_call;};
-       void operator()() {func();}
-       operator fptr () { return func; }
+        void operator()() {func();}
+        operator fptr () { return func; }
         ~y () {++destroyed;} 
     };
 
@@ -1134,10 +1144,15 @@ TEST_CASE("usertype/destructor-tests", "Show that proper copies / destruction ha
     static void* last_call = nullptr;
     struct x { 
         x() {++created;}
+        x(const x&) {++created;}
+        x(x&&) {++created;}
+        x& operator=(const x&) {return *this;}
+        x& operator=(x&&) {return *this;}
         ~x () {++destroyed;} 
     };
     {
         sol::state lua;
+        lua.new_usertype<x>("x");
         x x1;
         x x2;
         lua.set("x1copy", x1, "x2copy", x2, "x1ref", std::ref(x1));
@@ -1146,7 +1161,6 @@ TEST_CASE("usertype/destructor-tests", "Show that proper copies / destruction ha
         x& x1ref = lua["x1ref"];
         REQUIRE(created == 4);
         REQUIRE(destroyed == 0);
-        REQUIRE_FALSE(last_call == &x1);
         REQUIRE(std::addressof(x1) == std::addressof(x1ref));
     }
     REQUIRE(created == 4);