coins_ledger/
protocol.rs

1use crate::{Ledger, LedgerError};
2
3/// A Ledger Recovery. A the device to perform
4/// some operation. Protocols are run in a task, and may send multiple
5/// commands to the device, and receive multiple responses. The protocol has
6/// exclusive access to the transport while it is running.
7///
8/// The protocol may fail, and the [`LedgerProtocol::recover`] function will
9/// be invoked. The protocol may also fail to recover, in which case future
10/// uses of the device may fail.
11pub trait LedgerProtocol {
12    /// The output of the protocol.
13    type Output;
14
15    /// Run the protocol. This sends commands to the device, and receives
16    /// responses. The transport is locked while this function is running.
17    /// If the protocol fails, the app may be in an undefined state, and
18    /// the [`LedgerProtocol::recover`] function will be invoked.
19    ///
20    fn execute(&mut self, transport: &mut Ledger) -> Result<Self::Output, LedgerError>;
21
22    /// Run recovery if the protocol fails.
23    ///
24    /// This is invoked after the protocol fails. This function should attempt
25    /// to recover the app on the device to a known state.
26    ///
27    /// Multi-APDU protocols MUST override this function. The recommended
28    /// implementation is to retrieve a pubkey from the device twice.
29    fn recover(&self, _transport: &mut Ledger) -> Result<(), LedgerError> {
30        Ok(())
31    }
32
33    /// Run the protocol. This sends commands to the device, and receives
34    /// responses. The transport is locked while this function is running.
35    fn run(&mut self, transport: &mut Ledger) -> Result<Self::Output, LedgerError> {
36        match self.execute(transport) {
37            Ok(output) => Ok(output),
38            Err(e) => {
39                // TODO: make less ugly
40                #[cfg(target_arch = "wasm32")]
41                log::error!("Protocol failed, running recovery: {}", e);
42                #[cfg(not(target_arch = "wasm32"))]
43                tracing::error!(err = %e, "Protocol failed, running recovery.");
44
45                if let Err(e) = self.recover(transport) {
46                    #[cfg(target_arch = "wasm32")]
47                    log::error!("Recovery failed: {}", e);
48                    #[cfg(not(target_arch = "wasm32"))]
49                    tracing::error!(err = %e, "Recovery failed.");
50                }
51
52                Err(e)
53            }
54        }
55    }
56}
coins_ledger/protocol.rs

coins_ledger/
protocol.rs
