Clean the code and comments of registering C functions to Lua

[simgrid.git] / src / bindings / lua / lua_utils.c

diff --git a/src/bindings/lua/lua_utils.c b/src/bindings/lua/lua_utils.c
index 3f1f523..24bd4ab 100644 (file)
--- a/src/bindings/lua/lua_utils.c
+++ b/src/bindings/lua/lua_utils.c
@@ -6,6 +6,7 @@
 
 /* SimGrid Lua helper functions                                             */
 
+#include <lauxlib.h>
 #include "lua_utils.h"
 #include "xbt.h"
 #include "xbt/log.h"
@@ -137,6 +138,39 @@ void sglua_stack_dump(const char* msg, lua_State* L)
   }
 }
 
+/**
+ * \brief Like luaL_checkudata, with additional debug logs.
+ *
+ * This function is for debugging purposes only.
+ *
+ * \param L a lua state
+ * \param ud index of the userdata to check in the stack
+ * \param tname key of the metatable of this userdata in the registry
+ */
+void* sglua_checkudata_debug(lua_State* L, int ud, const char* tname)
+{
+  XBT_DEBUG("Checking the userdata: ud = %d", ud);
+  sglua_stack_dump("my_checkudata: ", L);
+  void* p = lua_touserdata(L, ud);
+  lua_getfield(L, LUA_REGISTRYINDEX, tname);
+  const void* correct_mt = lua_topointer(L, -1);
+
+  int has_mt = lua_getmetatable(L, ud);
+  XBT_DEBUG("Checking the userdata: has metatable ? %d", has_mt);
+  const void* actual_mt = NULL;
+  if (has_mt) {
+    actual_mt = lua_topointer(L, -1);
+    lua_pop(L, 1);
+  }
+  XBT_DEBUG("Checking the task's metatable: expected %p, found %p", correct_mt, actual_mt);
+  sglua_stack_dump("my_checkudata: ", L);
+
+  if (p == NULL || !lua_getmetatable(L, ud) || !lua_rawequal(L, -1, -2))
+    luaL_typerror(L, ud, tname);
+  lua_pop(L, 2);
+  return p;
+}
+
 /**
  * @brief Writes the specified data into a memory buffer.
  *