Method onReadable

src/core/EvdevEncoderManager.cpp:224–309

}

void EvdevEncoderManager::onReadable()
{
    if (m_fd < 0) return;
    struct input_event ev[32];
    while (true) {
        ssize_t n = ::read(m_fd, ev, sizeof(ev));
        if (n < 0) {
            if (errno == EAGAIN || errno == EWOULDBLOCK) break;
            // ENODEV typically means the BT dial disconnected.
            if (errno == ENODEV) {
                qCInfo(lcDevices) << "EvdevEncoderManager: device removed";
                closeFd();
                m_rescanTimer->start();  // wait for hot-plug re-add
                return;
            }
            qCWarning(lcDevices) << "EvdevEncoderManager: read err"
                                 << std::strerror(errno);
            closeFd();
            return;
        }
        if (n == 0) break;
        const int count = static_cast<int>(n / sizeof(input_event));
        for (int i = 0; i < count; ++i) {
            const struct input_event& e = ev[i];
            if (e.type != EV_KEY) continue;

            const int keycode = e.code;
            const int value   = e.value;  // 0 = release, 1 = press, 2 = autorepeat

            // Rotary: emit a tick per press or autorepeat tick.  The
            // ~30 Hz autorepeat rate from the dial firmware gives a
            // natural acceleration feel under continuous rotation.
            if (keycode == kRotaryCwKey) {
                if (value == 1 || value == 2) emit tuneSteps(+1);
                continue;
            }
            if (keycode == kRotaryCcwKey) {
                if (value == 1 || value == 2) emit tuneSteps(-1);
                continue;
            }

            // Modifier state for chord assembly.
            if (keycode == KEY_LEFTCTRL || keycode == KEY_RIGHTCTRL) {
                m_ctrlDown = (value != 0);
                if (!m_ctrlDown) {
                    // Ctrl released — chord window closing.  Reset
                    // compound flags so the next chord starts clean.
                    m_lastNonModKey = -1;
                    m_prevsongAlongsideCtrl = false;
                }
                continue;
            }

            // PREVIOUSSONG can arrive alongside a Ctrl chord (Mode Cycle
            // emits Ctrl+Y+KEY_PREVIOUSSONG as a compound).  Track that
            // it was present during a chord window so we can emit the
            // compound signature.
            if (keycode == KEY_PREVIOUSSONG && m_ctrlDown && value == 1) {