src/utility.c

   1 /* LuaEvent - Copyright (C) 2007,2012 Thomas Harning <harningt@gmail.com>
   2  * Licensed as LGPL - See doc/COPYING for details */
   3 #include "utility.h"
   4 #include <lauxlib.h>
   5
   6 #define WEAK_REF_LOCATION le_register_utility
   7
   8 static void get_weakref_table(lua_State* L) {
   9         lua_pushlightuserdata(L, WEAK_REF_LOCATION);
  10         lua_gettable(L, LUA_REGISTRYINDEX);
  11 }
  12
  13 void le_weak_ref(lua_State* L, void* ptr, int idx) {
  14         get_weakref_table(L);
  15         lua_pushlightuserdata(L, ptr);
  16         if(idx < 0) idx-=2;
  17         lua_pushvalue(L, idx);
  18         lua_settable(L, -3);
  19 }
  20 void le_weak_unref(lua_State* L, void* ptr) {
  21         get_weakref_table(L);
  22         lua_pushlightuserdata(L, ptr);
  23         lua_pushnil(L);
  24         lua_settable(L, -3);
  25 }
  26
  27 void le_weak_get(lua_State* L, void* ptr) {
  28         get_weakref_table(L);
  29         lua_pushlightuserdata(L, ptr);
  30         lua_gettable(L, -2);
  31 }
  32
  33 static void push_weak_table(lua_State* L, const char* mode) {
  34         lua_newtable(L);
  35         lua_createtable(L,0,1);
  36         lua_pushstring(L,mode);
  37         lua_setfield(L,-2,"__mode");
  38         lua_setmetatable(L,-2);
  39 }
  40
  41 void le_register_utility(lua_State* L) {
  42         lua_pushlightuserdata(L, WEAK_REF_LOCATION);
  43         push_weak_table(L, "v");
  44         lua_settable(L, LUA_REGISTRYINDEX);
  45 }