Function luaD_hook

depends/lua/src/ldo.c:253–277

** Call a hook for the given event. Make sure there is a hook to be ** called. (Both 'L->hook' and 'L->hookmask', which triggers this ** function, can be changed asynchronously by signals.) */

** function, can be changed asynchronously by signals.)
*/
void luaD_hook (lua_State *L, int event, int line) {
  lua_Hook hook = L->hook;
  if (hook && L->allowhook) {  /* make sure there is a hook */
    CallInfo *ci = L->ci;
    ptrdiff_t top = savestack(L, L->top);
    ptrdiff_t ci_top = savestack(L, ci->top);
    lua_Debug ar;
    ar.event = event;
    ar.currentline = line;
    ar.i_ci = ci;
    luaD_checkstack(L, LUA_MINSTACK);  /* ensure minimum stack size */
    ci->top = L->top + LUA_MINSTACK;
    lua_assert(ci->top <= L->stack_last);
    L->allowhook = 0;  /* cannot call hooks inside a hook */
    ci->callstatus |= CIST_HOOKED;
    lua_unlock(L);
    (*hook)(L, &ar);
    lua_lock(L);
    lua_assert(!L->allowhook);
    L->allowhook = 1;
    ci->top = restorestack(L, ci_top);
    L->top = restorestack(L, top);
    ci->callstatus &= ~CIST_HOOKED;
  }
}


static void callhook (lua_State *L, CallInfo *ci) {