From 40ed6ddb69b67e0c22556f3e565e16f6a2190316 Mon Sep 17 00:00:00 2001
From: Pavel Labath <pavelo@centrum.sk>
Date: Thu, 19 May 2011 12:59:50 +0200
Subject: c++ lua binding: replace std::function with FbTk::Slot

std::function is superior, but not supported on old compilers
---
 src/FbTk/Luamm.cc | 11 ++++-------
 src/FbTk/Luamm.hh | 49 ++++++++++++++++++++++++++++++++-----------------
 2 files changed, 36 insertions(+), 24 deletions(-)

diff --git a/src/FbTk/Luamm.cc b/src/FbTk/Luamm.cc
index a4a6eca..81a8fb3 100644
--- a/src/FbTk/Luamm.cc
+++ b/src/FbTk/Luamm.cc
@@ -30,7 +30,7 @@ namespace lua {
         const char cpp_exception_metatable[] = "lua::cpp_exception_metatable";
         const char cpp_function_metatable [] = "lua::cpp_function_metatable";
         const char lua_exception_namespace[] = "lua::lua_exception_namespace";
-        const char this_cpp_object		  [] = "lua::this_cpp_object";
+        const char this_cpp_object	  [] = "lua::this_cpp_object";
 
         // converts C++ exceptions to strings, so lua can do something with them
         int exception_to_string(lua_State *l)
@@ -245,7 +245,7 @@ namespace lua {
         newmetatable(cpp_function_metatable);
         pushboolean(false);
         rawsetfield(-2, "__metatable");
-        pushdestructor<cpp_function>();
+        pushdestructor<FbTk::Slot<int, state *> >();
         rawsetfield(-2, "__gc");
         pop();
 
@@ -399,16 +399,13 @@ namespace lua {
         return r;
     }
 
-    void state::pushclosure(const cpp_function &fn, int n)
+    void state::do_pushclosure(int n)
     {
-        checkstack(2);
-
-        createuserdata<cpp_function>(fn);
         rawgetfield(REGISTRYINDEX, cpp_function_metatable);
         setmetatable(-2);
 
         insert(-n-1);
-        lua_pushcclosure(cobj.get(), &closure_trampoline, n+1);
+        lua_pushcclosure(cobj, &closure_trampoline, n+1);
     }
 
     void state::rawgetfield(int index, const char *k) throw(std::bad_alloc)
diff --git a/src/FbTk/Luamm.hh b/src/FbTk/Luamm.hh
index 1df5825..5c8d382 100644
--- a/src/FbTk/Luamm.hh
+++ b/src/FbTk/Luamm.hh
@@ -27,13 +27,15 @@
 #include <stdexcept>
 
 #include <lua.h>
+#include <lauxlib.h>
+
+#include "Slot.hh"
 
 namespace lua {
     class state;
 
     typedef lua_Integer integer;
     typedef lua_Number number;
-    typedef std::function<int(state *)> cpp_function;
 
     enum {
         ENVIRONINDEX = LUA_ENVIRONINDEX,
@@ -175,7 +177,9 @@ namespace lua {
             }
 
         bool safe_compare(lua_CFunction trampoline, int index1, int index2);
-        public:
+        void do_pushclosure(int n);
+
+    public:
         state();
 
         /*
@@ -244,10 +248,12 @@ namespace lua {
         bool newmetatable(const char *tname) { return luaL_newmetatable(cobj.get(), tname); }
         void newtable() { lua_newtable(cobj.get()); }
         void *newuserdata(size_t size) { return lua_newuserdata(cobj.get(), size); }
-        // cpp_function can be anything that std::function can handle, everything else remains
+        // Functor can be anything that FbTk::Slot can handle, everything else remains
         // identical
-        void pushclosure(const cpp_function &fn, int n);
-        void pushfunction(const cpp_function &fn) { pushclosure(fn, 0); }
+        template<typename Functor>
+        void pushclosure(const Functor &fn, int n);
+        template<typename Functor>
+        void pushfunction(const Functor &fn) { pushclosure(fn, 0); }
         void pushstring(const char *s) { lua_pushstring(cobj.get(), s); }
         void pushstring(const char *s, size_t len) { lua_pushlstring(cobj.get(), s, len); }
         void pushstring(const std::string &s) { lua_pushlstring(cobj.get(), s.c_str(), s.size()); }
@@ -262,8 +268,7 @@ namespace lua {
         // std::function before we get a chance to call it. This pushes a function that simply
         // calls ~T when the time comes. Only set it as __gc on userdata of type T.
         template<typename T>
-            void pushdestructor()
-            { lua_pushcfunction(cobj.get(), &destroy_cpp_object<T>); }
+        void pushdestructor() { lua_pushcfunction(cobj.get(), &destroy_cpp_object<T>); }
 
         // type c, throw everything but the kitchen sink
         // call() is a protected mode call, we don't allow unprotected calls
@@ -279,7 +284,8 @@ namespace lua {
         void loadstring(const char *s) throw(lua::syntax_error, std::bad_alloc);
         bool next(int index);
         // register is a reserved word :/
-        void register_fn(const char *name, const cpp_function &f) { pushfunction(f); setglobal(name); }
+        template<typename Functor>
+        void register_fn(const char *name, const Functor &f) { pushfunction(f); setglobal(name); }
         void setfield(int index, const char *k);
         void setglobal(const char *name) { setfield(GLOBALSINDEX, name); }
         void settable(int index);
@@ -327,15 +333,24 @@ namespace lua {
     };
 
     template<typename T, typename... Args>
-        T* state::createuserdata(Args&&... args)
-        {
-            stack_sentry s(*this);
-
-            void *t = newuserdata(sizeof(T));
-            new(t) T(std::forward<Args>(args)...);
-            ++s;
-            return static_cast<T *>(t);
-        }
+    T* state::createuserdata(Args&&... args)
+    {
+        stack_sentry s(*this);
+
+        void *t = newuserdata(sizeof(T));
+        new(t) T(std::forward<Args>(args)...);
+        ++s;
+        return static_cast<T *>(t);
+    }
+
+    template<typename Functor>
+    void state::pushclosure(const Functor &fn, int n)
+    {
+        checkstack(2);
+
+        createuserdata<FbTk::SlotImpl<Functor, int, state *> >(fn);
+        do_pushclosure(n);
+    }
 }
 
 #endif // FBTK_LUAMM_HH
-- 
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