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/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at https://mozilla.org/MPL/2.0/. */
use core::fmt;
use alloc::boxed::Box;
#[derive(Debug)]
/// This type represents all possible errors operating a Foca instance.
pub enum Error {
/// Emitted whenever Foca receives a byte slice larger than
/// the configured limit ([`crate::Config::max_packet_size`]).
///
/// Doesn't affect Foca's state.
DataTooBig,
/// Attempt to [`crate::Foca::reuse_down_identity`] when not needed.
///
/// Doesn't affect Foca's state.
NotUndead,
/// Attempt to [`crate::Foca::change_identity`] with the same identity.
///
/// Doesn't affect Foca's state.
SameIdentity,
/// Expected to be connected when reaching this point.
/// Sentinel error to detect integration bugs.
///
/// Must not happen under normal circumstances.
NotConnected,
/// Reached the end of the probe cycle but expected
/// steps didn't happen. Bug in the runtime/scheduling
/// mechanism most likely.
///
/// Foca tries to resume normal operations after emitting this
/// error, but any occurance of it is a sign that something is
/// not behaving as expected
///
/// Must not happen under normal circumstances.
IncompleteProbeCycle,
/// Received data where the sender has the same
/// id as ourselves.
///
/// There's likely a member submitting wrong/manually-crafted
/// packets.
DataFromOurselves,
/// Data contains a message supposed to reach us via indirect
/// means.
///
/// There's likely a member submitting wrong/manually-crafted
/// packets.
IndirectForOurselves,
/// Data is in an unexpected format.
///
/// Doesn't affect Foca's state.
MalformedPacket,
/// Wraps [`crate::Codec`]'s `encode_*` failures.
/// Shouldn't happen under normal circumstances unless using a broken
/// codec.
///
/// Might have left Foca in a inconsistent state.
Encode(Box<dyn core::error::Error + Send + Sync>),
/// Wraps [`crate::Codec`]'s `decode_*` failures.
///
/// Can happen during normal operation when receiving junk data.
Decode(Box<dyn core::error::Error + Send + Sync>),
/// Wraps [`crate::BroadcastHandler`] failures.
///
/// Doesn't affect Foca's state.
CustomBroadcast(Box<dyn core::error::Error + Send + Sync>),
/// Configuration change not allowed.
///
/// Doesn't affact Foca's state.
///
/// See [`crate::Foca::set_config`].
InvalidConfig,
}
impl PartialEq for Error {
fn eq(&self, other: &Self) -> bool {
use alloc::string::ToString;
#[allow(clippy::match_same_arms)]
match (self, other) {
// Wrapped errors have to allocate to compare :(
// But PartialEq on an error type is mostly useful for tests
(Error::Encode(a), Error::Encode(b)) => a.to_string().eq(&b.to_string()),
(Error::Decode(a), Error::Decode(b)) => a.to_string().eq(&b.to_string()),
(Error::CustomBroadcast(a), Error::CustomBroadcast(b)) => {
a.to_string().eq(&b.to_string())
}
(Error::DataTooBig, Error::DataTooBig) => true,
(Error::NotConnected, Error::NotConnected) => true,
(Error::NotUndead, Error::NotUndead) => true,
(Error::SameIdentity, Error::SameIdentity) => true,
(Error::IncompleteProbeCycle, Error::IncompleteProbeCycle) => true,
(Error::DataFromOurselves, Error::DataFromOurselves) => true,
(Error::IndirectForOurselves, Error::IndirectForOurselves) => true,
(Error::MalformedPacket, Error::MalformedPacket) => true,
(Error::InvalidConfig, Error::InvalidConfig) => true,
// Instead of a catch-all here, we explicitly enumerate our variants
// so that when/if new errors are added we don't silently introduce
// a bug
(Error::Encode(_), _) => false,
(Error::Decode(_), _) => false,
(Error::CustomBroadcast(_), _) => false,
(Error::DataTooBig, _) => false,
(Error::NotConnected, _) => false,
(Error::NotUndead, _) => false,
(Error::SameIdentity, _) => false,
(Error::IncompleteProbeCycle, _) => false,
(Error::DataFromOurselves, _) => false,
(Error::IndirectForOurselves, _) => false,
(Error::MalformedPacket, _) => false,
(Error::InvalidConfig, _) => false,
}
}
}
impl fmt::Display for Error {
fn fmt(&self, formatter: &mut fmt::Formatter<'_>) -> fmt::Result {
#[allow(clippy::match_same_arms)]
match self {
Error::DataTooBig => {
formatter.write_str("Received data larger than maximum configured limit")
}
Error::NotUndead => formatter.write_str("Useless attempt to reuse a functioning Foca"),
Error::SameIdentity => {
formatter.write_str("New identity is the same as the current one")
}
Error::NotConnected => formatter.write_str("BUG! Expected to be connected, but wasn't"),
Error::IncompleteProbeCycle => {
formatter.write_str("BUG! Probe cycle finished without running its full course")
}
Error::DataFromOurselves => formatter.write_str(concat!(
"Received data from something claiming to have ",
"an identity equal to our own"
)),
Error::IndirectForOurselves => formatter.write_str(concat!(
"Received message that was supposed to reach us only ",
"via indirect means"
)),
Error::MalformedPacket => formatter.write_str("Payload with more data than expected"),
Error::Encode(err) => err.fmt(formatter),
Error::Decode(err) => err.fmt(formatter),
Error::CustomBroadcast(err) => err.fmt(formatter),
Error::InvalidConfig => formatter.write_str("Invalid configuration"),
}
}
}
impl core::error::Error for Error {}
#[cfg(test)]
mod tests {
fn ensure_send_sync<T: Send + Sync>(_val: T) {}
#[test]
fn errors_are_sync() {
ensure_send_sync(super::Error::InvalidConfig);
}
}