Function luaD_hook

3rd/lua-5.4.3/src/ldo.c:306–339

** Call a hook for the given event. Make sure there is a hook to be ** called. (Both 'L->hook' and 'L->hookmask', which trigger 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,
                              int ftransfer, int ntransfer) {
  lua_Hook hook = L->hook;
  if (hook && L->allowhook) {  /* make sure there is a hook */
    int mask = CIST_HOOKED;
    CallInfo *ci = L->ci;
    ptrdiff_t top = savestack(L, L->top);  /* preserve original 'top' */
    ptrdiff_t ci_top = savestack(L, ci->top);  /* idem for 'ci->top' */
    lua_Debug ar;
    ar.event = event;
    ar.currentline = line;
    ar.i_ci = ci;
    if (ntransfer != 0) {
      mask |= CIST_TRAN;  /* 'ci' has transfer information */
      ci->u2.transferinfo.ftransfer = ftransfer;
      ci->u2.transferinfo.ntransfer = ntransfer;
    }
    if (isLua(ci) && L->top < ci->top)
      L->top = ci->top;  /* protect entire activation register */
    luaD_checkstack(L, LUA_MINSTACK);  /* ensure minimum stack size */
    if (ci->top < L->top + LUA_MINSTACK)
      ci->top = L->top + LUA_MINSTACK;
    L->allowhook = 0;  /* cannot call hooks inside a hook */
    ci->callstatus |= mask;
    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 &= ~mask;
  }
}


/*