Method convertModMask

src/lib/platform/EiKeyState.cpp:115–187

}

std::uint32_t EiKeyState::convertModMask(xkb_mod_mask_t xkbModMaskIn) const
{
  // This is our own modifier mask, not xkb's.
  std::uint32_t modMaskOut = 0;

  for (xkb_mod_index_t xkbModIdx = 0; xkbModIdx < xkb_keymap_num_mods(m_xkbKeymap); xkbModIdx++) {
    const char *name = xkb_keymap_mod_get_name(m_xkbKeymap, xkbModIdx);

#ifdef HAVE_XKB_KEYMAP_MOD_GET_MASK
    // Available since xkbcommon v1.10
    // Note: xkb_keymap_mod_get_mask2 was added in v1.11 which accepts xkb_mod_index_t.
    const auto xkbModMask = xkb_keymap_mod_get_mask(m_xkbKeymap, name);
#else
    // HACK: in older xkbcommon we need to create the mask manually from the index.
    const xkb_mod_mask_t xkbModMask = (1 << xkbModIdx);
#endif

    // Skip modifiers that have no XKB mask (not mapped to any real modifier)
    // or are inactive. Without the xkbModMask == 0 check, modifiers with mask 0
    // incorrectly pass the test (0 & 0 == 0) and get processed as "active".
    if (xkbModMask == 0 || (xkbModMaskIn & xkbModMask) != xkbModMask)
      continue;

    /* added in libxkbcommon 1.8.0 in the same commit so we have all or none */
#ifndef XKB_VMOD_NAME_ALT
    static const auto XKB_VMOD_NAME_ALT = "Alt";
    static const auto XKB_VMOD_NAME_LEVEL3 = "LevelThree";
    static const auto XKB_VMOD_NAME_LEVEL5 = "LevelFive";
    static const auto XKB_VMOD_NAME_META = "Meta";
    static const auto XKB_VMOD_NAME_NUM = "NumLock";
    static const auto XKB_VMOD_NAME_SCROLL = "ScrollLock";
    static const auto XKB_VMOD_NAME_SUPER = "Super";
    static const auto XKB_VMOD_NAME_HYPER = "Hyper";
    static const auto XKB_MOD_NAME_MOD2 = "Mod2";
    static const auto XKB_MOD_NAME_MOD3 = "Mod3";
    static const auto XKB_MOD_NAME_MOD5 = "Mod5";
#endif

    // From wismill (xkbcommon maintainer):
    // Meta is usually encoded like Alt, i.e. to Mod1. In that case, both share the same state.
    // Added to that, if KDE interprets Meta as Super (the logo key), then it might explain the mess.

    if (strcmp(XKB_MOD_NAME_SHIFT, name) == 0)
      modMaskOut |= (1 << kKeyModifierBitShift);
    else if (strcmp(XKB_MOD_NAME_CAPS, name) == 0)
      modMaskOut |= (1 << kKeyModifierBitCapsLock);
    else if (strcmp(XKB_MOD_NAME_CTRL, name) == 0)
      modMaskOut |= (1 << kKeyModifierBitControl);
    else if (strcmp(XKB_MOD_NAME_ALT, name) == 0 || strcmp(XKB_VMOD_NAME_ALT, name) == 0)
      modMaskOut |= (1 << kKeyModifierBitAlt);
    else if (strcmp(XKB_MOD_NAME_LOGO, name) == 0 ||   // aka windows/command key
             strcmp(XKB_VMOD_NAME_SUPER, name) == 0 || // virtual; usually mapped to logo key
             strcmp(XKB_VMOD_NAME_HYPER, name) == 0)   // virtual; often mapped to caps lock key
      modMaskOut |= (1 << kKeyModifierBitSuper);
    else if (strcmp(XKB_MOD_NAME_MOD5, name) == 0 || strcmp(XKB_VMOD_NAME_LEVEL3, name) == 0)
      modMaskOut |= (1 << kKeyModifierBitAltGr);
    else if (strcmp(XKB_VMOD_NAME_LEVEL5, name) == 0)
      modMaskOut |= (1 << kKeyModifierBitLevel5Lock);