bug#74423: Low level key events

[Cecilio Pardo]

On 19/11/2024 0:49, Po Lu wrote:

> You are computing the modifier event to be generated incorrectly.  You
> should search the modifier map (dpyinfo->modmap) for columns containing
> received keysyms, and compare modifier bits derived from the rows where
> they appear against meta_mod_mask, shift_lock_mask, alt_mod_mask,
> super_mod_mask, and hyper_mod_mask in the display structure, or CtrlMask
> and ShiftMask.

Thanks for the guidance. Does this look ok?


Lisp_Object
x_get_modifier_for_keycode (struct x_display_info *dpyinfo,
                            int keycode)
{
#ifdef HAVE_XKB
  if (dpyinfo->xkb_desc)
    for (int mod = 0; mod < XkbNumModifiers; mod++)
      {
        int mask = (1 << mod);
        if (dpyinfo->xkb_desc->map->modmap[keycode] & mask)
          {
            if (mask == ShiftMask)
              return Qshift;
            if (mask == ControlMask)
              return Qctrl;
            if (mask == dpyinfo->meta_mod_mask)
              return Qmeta;
            if (mask == dpyinfo->alt_mod_mask)
              return Qalt;
            if (mask == dpyinfo->super_mod_mask)
              return Qsuper;
            if (mask == dpyinfo->hyper_mod_mask)
              return Qhyper;
          }
      }
#endif
  XModifierKeymap *map = dpyinfo->modmap;
  if (map)
    for (int mod = 0; mod < 8; mod++)
      {
        int mask = (1 << mod);
        for (int key = 0; key < map->max_keypermod; key++)
          if (map->modifiermap[mod * map->max_keypermod + key] == keycode)
            {
              if (mask == ShiftMask)
                return Qshift;
              if (mask == ControlMask)
                return Qctrl;
              if (mask == dpyinfo->meta_mod_mask)
                return Qmeta;
              if (mask == dpyinfo->alt_mod_mask)
                return Qalt;
              if (mask == dpyinfo->super_mod_mask)
                return Qsuper;
              if (mask == dpyinfo->hyper_mod_mask)
                return Qhyper;
            }
      }
  return Qnil;
}