trezor-firmware/core/src/apps/management/get_next_u2f_counter.py

from typing import TYPE_CHECKING

if TYPE_CHECKING:
    from trezor.messages import GetNextU2FCounter, NextU2FCounter


async def get_next_u2f_counter(msg: GetNextU2FCounter) -> NextU2FCounter:
    import storage.device as storage_device
    from trezor.wire import NotInitialized
    from trezor.enums import ButtonRequestType
    from trezor.messages import NextU2FCounter
    from trezor.ui.layouts import confirm_action

    if not storage_device.is_initialized():
        raise NotInitialized("Device is not initialized")

    await confirm_action(
        "get_u2f_counter",
        "Get U2F counter",
        description="Increase and retrieve the U2F counter?",
        br_code=ButtonRequestType.ProtectCall,
    )

    return NextU2FCounter(u2f_counter=storage_device.next_u2f_counter())