void LuaInterface::pushCppFunction(const LuaCppFunction& func)
{
// create a pointer to func (this pointer will hold the function existence)
new(newUserdata(sizeof(LuaCppFunctionPtr))) LuaCppFunctionPtr(new LuaCppFunction(func));
// sets the userdata __gc metamethod, needed to free the function pointer when it gets collected
newTable();
pushCFunction(&LuaInterface::luaCollectCppFunction);
setField("__gc");
setMetatable();
// actually pushes a C function callback that will call the cpp function
pushCFunction(&LuaInterface::luaCppFunctionCallback, 1);
}
int LuaInterface::safeCall(int numArgs, int numRets)
{
assert(hasIndex(-numArgs-1));
// saves the current stack size for calculating the number of results later
int previousStackSize = stackSize();
// pushes error function
int errorFuncIndex = previousStackSize - numArgs;
pushCFunction(&LuaInterface::luaErrorHandler);
insert(errorFuncIndex);
// calls the function in protected mode (means errors will be caught)
int ret = pcall(numArgs, LUA_MULTRET, errorFuncIndex);
remove(errorFuncIndex); // remove error func
// if there was an error throw an exception
if(ret != 0)
throw LuaException(popString());
int rets = (stackSize() + numArgs + 1) - previousStackSize;
while(numRets != -1 && rets != numRets) {
if(rets < numRets) {
pushNil();
rets++;
} else {
pop();
rets--;
}
}
// returns the number of results
return rets;
}
void LuaInterface::createLuaState()
{
// creates lua state
L = luaL_newstate();
if(!L)
g_logger.fatal("Unable to create lua state");
// load lua standard libraries
luaL_openlibs(L);
// load bit32 lib for bitwise operations
luaopen_bit32(L);
// creates weak table
newTable();
newTable();
pushString("v");
setField("__mode");
setMetatable();
m_weakTableRef = ref();
// installs script loader
getGlobal("package");
getField("loaders");
pushCFunction(&LuaInterface::luaScriptLoader);
rawSeti(5);
pop(2);
// replace dofile
pushCFunction(&LuaInterface::lua_dofile);
setGlobal("dofile");
// dofiles
pushCFunction(&LuaInterface::lua_dofiles);
setGlobal("dofiles");
// replace loadfile
pushCFunction(&LuaInterface::lua_loadfile);
setGlobal("loadfile");
}
