LUALIB_API void luaL_openlib(lua_State *L, const char *libname, const luaL_Reg *l, int nup) { lj_lib_checkfpu(L); if (libname) { int size = libsize(l); /* check whether lib already exists */ luaL_findtable(L, LUA_REGISTRYINDEX, "_LOADED", 16); lua_getfield(L, -1, libname); /* get _LOADED[libname] */ if (!lua_istable(L, -1)) { /* not found? */ lua_pop(L, 1); /* remove previous result */ /* try global variable (and create one if it does not exist) */ if (luaL_findtable(L, LUA_GLOBALSINDEX, libname, size) != NULL) lj_err_callerv(L, LJ_ERR_BADMODN, libname); lua_pushvalue(L, -1); lua_setfield(L, -3, libname); /* _LOADED[libname] = new table */ } lua_remove(L, -2); /* remove _LOADED table */ lua_insert(L, -(nup+1)); /* move library table to below upvalues */ } for (; l->name; l++) { int i; for (i = 0; i < nup; i++) /* copy upvalues to the top */ lua_pushvalue(L, -nup); lua_pushcclosure(L, l->func, nup); lua_setfield(L, -(nup+2), l->name); } lua_pop(L, nup); /* remove upvalues */ }
static int lj_cf_package_require(lua_State *L) { const char *name = luaL_checkstring(L, 1); int i; lua_settop(L, 1); /* _LOADED table will be at index 2 */ lua_getfield(L, LUA_REGISTRYINDEX, "_LOADED"); lua_getfield(L, 2, name); if (lua_toboolean(L, -1)) { /* is it there? */ if (lua_touserdata(L, -1) == sentinel) /* check loops */ luaL_error(L, "loop or previous error loading module " LUA_QS, name); return 1; /* package is already loaded */ } /* else must load it; iterate over available loaders */ lua_getfield(L, LUA_ENVIRONINDEX, "loaders"); if (!lua_istable(L, -1)) luaL_error(L, LUA_QL("package.loaders") " must be a table"); lua_pushliteral(L, ""); /* error message accumulator */ for (i = 1; ; i++) { lua_rawgeti(L, -2, i); /* get a loader */ if (lua_isnil(L, -1)) luaL_error(L, "module " LUA_QS " not found:%s", name, lua_tostring(L, -2)); lua_pushstring(L, name); lua_call(L, 1, 1); /* call it */ if (lua_isfunction(L, -1)) /* did it find module? */ break; /* module loaded successfully */ else if (lua_isstring(L, -1)) /* loader returned error message? */ lua_concat(L, 2); /* accumulate it */ else lua_pop(L, 1); } lua_pushlightuserdata(L, sentinel); lua_setfield(L, 2, name); /* _LOADED[name] = sentinel */ lua_pushstring(L, name); /* pass name as argument to module */ lua_call(L, 1, 1); /* run loaded module */ if (!lua_isnil(L, -1)) /* non-nil return? */ lua_setfield(L, 2, name); /* _LOADED[name] = returned value */ lua_getfield(L, 2, name); if (lua_touserdata(L, -1) == sentinel) { /* module did not set a value? */ lua_pushboolean(L, 1); /* use true as result */ lua_pushvalue(L, -1); /* extra copy to be returned */ lua_setfield(L, 2, name); /* _LOADED[name] = true */ } lj_lib_checkfpu(L); return 1; }