From: Yuval Lifshitz <ylifshit@redhat.com>
Date: Sun, 14 May 2023 13:47:56 +0000 (+0000)
Subject: rgw/lua: use lua_gettop instead of magic numbers
X-Git-Tag: v19.0.0~909^2~2
X-Git-Url: http://git-server-git.apps.pok.os.sepia.ceph.com/?a=commitdiff_plain;h=2c703f3f56929203b35de82ad3a31a796232bd25;p=ceph.git

rgw/lua: use lua_gettop instead of magic numbers

Signed-off-by: Yuval Lifshitz <ylifshit@redhat.com>
---

diff --git a/src/rgw/rgw_lua_utils.h b/src/rgw/rgw_lua_utils.h
index cc77dae7a896..ba703f1c57d0 100644
--- a/src/rgw/rgw_lua_utils.h
+++ b/src/rgw/rgw_lua_utils.h
@@ -126,31 +126,42 @@ void create_metatable(lua_State* L, bool toplevel, Upvalues... upvalues)
   }
   // create metatable
   [[maybe_unused]] const auto rc = luaL_newmetatable(L, MetaTable::Name().c_str());
+  const auto table_stack_pos = lua_gettop(L);
+
+  // add "index" closure to metatable
   lua_pushliteral(L, "__index");
   for (const auto upvalue : upvalue_arr) {
     lua_pushlightuserdata(L, upvalue);
   }
   lua_pushcclosure(L, MetaTable::IndexClosure, upvals_size);
-  lua_rawset(L, -3);
+  lua_rawset(L, table_stack_pos);
+
+  // add "newindex" closure to metatable
   lua_pushliteral(L, "__newindex");
   for (const auto upvalue : upvalue_arr) {
     lua_pushlightuserdata(L, upvalue);
   }
   lua_pushcclosure(L, MetaTable::NewIndexClosure, upvals_size);
-  lua_rawset(L, -3);
+  lua_rawset(L, table_stack_pos);
+
+  // add "pairs" closure to metatable
   lua_pushliteral(L, "__pairs");
   for (const auto upvalue : upvalue_arr) {
     lua_pushlightuserdata(L, upvalue);
   }
   lua_pushcclosure(L, MetaTable::PairsClosure, upvals_size);
-  lua_rawset(L, -3);
+  lua_rawset(L, table_stack_pos);
+
+  // add "len" closure to metatable
   lua_pushliteral(L, "__len");
   for (const auto upvalue : upvalue_arr) {
     lua_pushlightuserdata(L, upvalue);
   }
   lua_pushcclosure(L, MetaTable::LenClosure, upvals_size);
-  lua_rawset(L, -3);
+  lua_rawset(L, table_stack_pos);
+
   // tie metatable and table
+  ceph_assert(lua_gettop(L) == table_stack_pos);
   lua_setmetatable(L, -2);
 }