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`newproxy' uses its own weaktable

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This commit is contained in:
Roberto Ierusalimschy
2002-07-01 16:23:58 -03:00
parent 9f4b5b5232
commit aa3da1605c
3 changed files with 24 additions and 35 deletions
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35
lbaselib.c
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@@ -1,5 +1,5 @@
/*
** $Id: lbaselib.c,v 1.87 2002/06/26 19:28:44 roberto Exp roberto $
** $Id: lbaselib.c,v 1.88 2002/06/26 20:36:17 roberto Exp roberto $
** Basic library
** See Copyright Notice in lua.h
*/
@@ -323,27 +323,27 @@ static int luaB_tostring (lua_State *L) {
static int luaB_newproxy (lua_State *L) {
static const char dummy = '\0';
lua_settop(L, 1);
luaL_weakregistry(L); /* get weak registry */
lua_newuserdata(L, 0); /* create proxy */
if (lua_toboolean(L, 1) == 0)
return 1; /* no metatable */
else if (lua_isboolean(L, 1)) {
lua_newtable(L); /* create a new metatable `m' ... */
lua_pushvalue(L, -1); /* ... and mark `m' as a valid metatable */
lua_pushudataval(L, (void *)&dummy);
lua_rawset(L, 2); /* weakregistry[m] = &dummy */
lua_pushboolean(L, 1);
lua_rawset(L, lua_upvalueindex(1)); /* weaktable[m] = true */
}
else {
if (lua_getmetatable(L, 1)) /* check whether registry[m] == &dummy */
lua_rawget(L, 2);
luaL_arg_check(L, (char *)lua_touserdata(L, -1) == &dummy, 1,
"boolean/proxy expected");
lua_getmetatable(L, 1); /* metatable is valid */
int validproxy = 0; /* to check if weaktable[metatable(u)] == true */
if (lua_getmetatable(L, 1)) {
lua_rawget(L, lua_upvalueindex(1));
validproxy = lua_toboolean(L, -1);
lua_pop(L, 1); /* remove value */
}
luaL_arg_check(L, validproxy, 1, "boolean/proxy expected");
lua_getmetatable(L, 1); /* metatable is valid; get it */
}
lua_setmetatable(L, 3);
lua_pushvalue(L, 3);
lua_setmetatable(L, 2);
return 1;
}
@@ -461,7 +461,6 @@ static const luaL_reg base_funcs[] = {
{"tostring", luaB_tostring},
{"type", luaB_type},
{"assert", luaB_assert},
{"newproxy", luaB_newproxy},
{"unpack", luaB_unpack},
{"rawequal", luaB_rawequal},
{"rawget", luaB_rawget},
@@ -569,6 +568,16 @@ static void base_open (lua_State *L) {
lua_pushliteral(L, "_VERSION");
lua_pushliteral(L, LUA_VERSION);
lua_rawset(L, -3); /* set global _VERSION */
/* `newproxy' needs a weaktable as upvalue */
lua_pushliteral(L, "newproxy");
lua_newtable(L); /* new table `w' */
lua_newtable(L); /* create `w's metatable */
lua_pushliteral(L, "__mode");
lua_pushliteral(L, "k");
lua_rawset(L, -3); /* metatable(w).__mode = "k" */
lua_setmetatable(L, -2);
lua_pushcclosure(L, luaB_newproxy, 1);
lua_rawset(L, -3); /* set global `newproxy' */
lua_rawset(L, -1); /* set global _G */
}