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Added a function to verify the type of userdata.

ver1_5_1
Chris Laurel 2003-04-14 17:43:10 +00:00
parent 51ca00c120
commit 157bab3c8d
1 changed files with 39 additions and 3 deletions
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42
src/celestia/celx.cpp
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@ -51,7 +51,7 @@ static const int _Rotation = 5;
static void lua_pushclass(lua_State* l, int id)
{
lua_pushlstring(l, ClassNames[id], strlen(ClassNames[id]) - 1);
lua_pushlstring(l, ClassNames[id], strlen(ClassNames[id]));
}
static void lua_setclass(lua_State* l, int id)
@ -65,6 +65,37 @@ static void lua_setclass(lua_State* l, int id)
}
// Verify that an object at location index on the stack is of the
// specified class
static void* CheckUserData(lua_State* l, int index, int id)
{
// get registry[metatable]
if (!lua_getmetatable(l, index))
return NULL;
lua_rawget(l, LUA_REGISTRYINDEX);
if (lua_type(l, -1) != LUA_TSTRING)
{
cout << "CheckUserData failed! Unregistered class.\n";
lua_pop(l, 1);
return NULL;
}
const char* classname = lua_tostring(l, -1);
if (classname != NULL && strcmp(classname, ClassNames[id]) == 0)
{
lua_pop(l, 1);
return lua_touserdata(l, index);
}
else
{
cout << "CheckUserData failed! Expected " << ClassNames[id] << " but got " << classname << '\n';
lua_pop(l, 1);
return NULL;
}
}
LuaState::LuaState() :
state(NULL),
costate(NULL),
@ -274,9 +305,11 @@ static int object_new(lua_State* l, const Selection& sel)
static Selection* to_object(lua_State* l, int index)
{
cout << "to_object\n"; cout.flush();
// TODO: need to verify that this is actually an object, not some
// other userdata
return static_cast<Selection*>(lua_touserdata(l, index));
// return static_cast<Selection*>(lua_touserdata(l, index));
return static_cast<Selection*>(CheckUserData(l, index, _Object));
}
static int object_tostring(lua_State* l)
@ -316,7 +349,10 @@ static void CreateObjectMetaTable(lua_State* l)
lua_newtable(l);
lua_pushclass(l, _Object);
lua_pushvalue(l, -2);
lua_rawset(l, LUA_REGISTRYINDEX);
lua_rawset(l, LUA_REGISTRYINDEX); // registry.name = metatable
lua_pushvalue(l, -1);
lua_pushclass(l, _Object);
lua_rawset(l, LUA_REGISTRYINDEX); // registry.metatable = name
lua_pushliteral(l, "__tostring");
lua_pushvalue(l, -2);