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object.c
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object.c
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#include "object.h"
#include <stdarg.h>
int object_gc( lua_State* L )
{
if( lua_type( L, 1 ) != LUA_TUSERDATA )
{
luaL_error( L, "libui not a userdata" );
return 0;
}
int object_signature = 0;
// fetch object signature from its metatable data
lua_getmetatable( L, 1 );
if( lua_istable( L, -1 ) )
{
lua_pushstring( L, "__libui_signature" );
lua_gettable( L, -2 );
if( lua_isinteger( L, -1 ) )
{
object_signature = lua_tointeger( L, -1 );
}
lua_pop( L, 1 );
}
lua_pop( L, 1 );
if( object_signature == 0 )
{
luaL_error( L, "libui not an object" );
return 0;
}
// if( object_signature == uiMenuSignature || object_signature == uiMenuItemSignature )
// {
// can't delete anything from menus
// return 0;
// }
// TODO maybe one day when libui gets an OnDestroy callback this can be implemented fully.
return 0;
}
// NOTE: when calling object_create, the last argument MUST be 0 (just add it on the end)
void* object_create( lua_State* L, void* object, int signature, ... )
{
// userdata wrapper is a single pointer
void** p = lua_newuserdata( L, sizeof(object) );
*p = object;
// create a metatable
lua_newtable( L );
// copy control signature to metatable
lua_pushinteger( L, signature );
lua_setfield( L, -2, "__libui_signature" );
// allow objects to override the __gc metamethod
lua_pushcfunction( L, object_gc );
lua_setfield( L, -2, "__gc" );
// variable list of meta functions
va_list ap;
va_start( ap, signature );
while( 1 )
{
luaL_Reg* fn = va_arg( ap, luaL_Reg* );
if( fn )
luaL_setfuncs( L, fn, 0 );
else
break;
}
va_end(ap);
lua_pushvalue( L, -1 );
lua_setfield( L, -2, "__index" );
lua_pushvalue( L, -1 );
lua_setfield( L, -2, "__newindex" );
// create meta data table in registry
lua_pushlightuserdata( L, object );
lua_newtable( L );
lua_pushvalue( L, -3 );
lua_setfield( L, -2, "meta" );
lua_settable( L, LUA_REGISTRYINDEX );
lua_setmetatable( L, -2 );
return object;
}
int object_copy( lua_State* L, void* object )
{
// retreive meta table from registry
lua_pushlightuserdata( L, object );
lua_gettable( L, LUA_REGISTRYINDEX );
// object not registered, can't continue
if( ! lua_istable( L, -1 ) )
{
lua_pop( L, 1 );
return 0;
}
// get function table, pop previous table
lua_getfield( L, -1, "meta" );
lua_rotate( L, -2, 1 );
lua_pop( L, 1 );
// meta table not valid, can't continue
if( ! lua_istable( L, -1 ) )
{
lua_pop( L, 1 );
return 0;
}
void** p = lua_newuserdata( L, sizeof(object) );
*p = object;
lua_rotate( L, -2, 1 );
lua_setmetatable( L, -2 );
return 1;
}
void* get_object( lua_State* L, int idx, int* signature )
{
if( lua_type( L, idx ) != LUA_TUSERDATA )
{
luaL_error( L, "libui not a userdata" );
return 0;
}
int object_signature = 0;
// fetch object signature from its metatable data
lua_getmetatable( L, idx );
if( lua_istable( L, -1 ) )
{
lua_pushstring( L, "__libui_signature" );
lua_gettable( L, -2 );
if( lua_isinteger( L, -1 ) )
{
object_signature = lua_tointeger( L, -1 );
}
lua_pop( L, 1 );
}
lua_pop( L, 1 );
void** p = lua_touserdata( L, idx );
if( p == NULL || *p == NULL )
{
luaL_error( L, "libui object pointer invalid (NULL)" );
return 0;
}
void* o = *p;
// check object is valid in registry
lua_pushlightuserdata( L, o );
lua_gettable( L, LUA_REGISTRYINDEX );
if( lua_isnil( L, -1 ) )
{
luaL_error( L, "libui object is not valid in registry (it might have been deleted)" );
return 0;
}
lua_pop( L, 1 );
if( signature )
{
*signature = object_signature;
}
return o;
}
void* get_object_unsafe( lua_State* L, int idx )
{
void** p = lua_touserdata( L, idx );
return *p;
}
void* check_object( lua_State* L, int idx, int signature )
{
int s = 0;
void* o = get_object( L, idx, &s );
if( s && s == signature )
{
return o;
}
return 0;
}
int is_object( lua_State* L, int idx, int signature )
{
if( lua_type( L, idx ) != LUA_TUSERDATA )
{
// Not a userdata
return 0;
}
int object_signature = 0;
// fetch object signature from its metatable data
lua_getmetatable( L, idx );
int e = lua_istable( L, -1 );
if( e )
{
lua_pushstring( L, "__libui_signature" );
lua_gettable( L, -2 );
e = lua_isinteger( L, -1 );
if( e )
{
object_signature = lua_tointeger( L, -1 );
}
lua_pop( L, 1 );
if( !e )
{
// libui object signature not found in meta table
return 0;
}
}
lua_pop( L, 1 );
if( !e )
{
// no metatable present
return 0;
}
void** p = lua_touserdata( L, idx );
if( p == NULL || *p == NULL )
{
// pointer invalid
return 0;
}
void* o = *p;
// check object is valid in registry
lua_pushlightuserdata( L, o );
lua_gettable( L, LUA_REGISTRYINDEX );
e = lua_isnil( L, -1 );
lua_pop( L, 1 );
if( e )
{
// libui object is not valid in registry (it might have been deleted)
return 0;
}
if( signature == 0 || signature == object_signature )
{
return 1;
}
// signature mismatch
return 0;
}
// get object userdata from registry, with a meta function
void object_retreive_with_function( lua_State* L, void* obj, char const* metafunction )
{
lua_pushlightuserdata( L, obj );
lua_gettable( L, LUA_REGISTRYINDEX );
// object not registered, can't continue
if( ! lua_istable( L, -1 ) )
{
lua_pop( L, 1 );
luaL_error( L, "Object is not registered" );
}
// get function table, pop previous table
lua_getfield( L, -1, "meta" );
lua_rotate( L, -2, 1 );
lua_pop( L, 1 );
// meta table not valid, can't continue
if( ! lua_istable( L, -1 ) )
{
lua_pop( L, 1 );
luaL_error( L, "Object meta table invalid" );
}
// check that the function is valid in the caller
lua_getfield( L, -1, metafunction );
// construct area object for use in function call
lua_rotate( L, -2, 1 );
void** p = lua_newuserdata( L, sizeof(obj) );
*p = obj;
lua_rotate( L, -2, 1 );
lua_setmetatable( L, -2 );
lua_rotate( L, -2, 1 );
// stack is now: function, object
lua_rotate( L, -2, 1 );
}