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crate::ix!();
/**
| The various states a (txhash,peer) pair can be
| in.
|
| Note that CANDIDATE is split up into
| 3 substates (DELAYED, BEST, READY), allowing
| more efficient implementation. Also note that
| the sorting order of ByTxHashView relies on the
| specific order of values in this enum.
|
| Expected behaviour is:
|
| - When first announced by a peer, the state
| is CANDIDATE_DELAYED until reqtime is
| reached.
|
| - Announcements that have reached their
| reqtime but not been requested will be
| either CANDIDATE_READY or
| CANDIDATE_BEST. Neither of those has an
| expiration time; they remain in that state
| until they're requested or no longer
| needed. CANDIDATE_READY announcements are
| promoted to CANDIDATE_BEST when they're the
| best one left.
|
| - When requested, an announcement will be in
| state REQUESTED until expiry is reached.
|
| - If expiry is reached, or the peer replies
| to the request (either with NOTFOUND or the
| tx), the state becomes COMPLETED.
*/
#[repr(u8)]
#[derive(Clone,PartialEq,Eq)]
pub enum State {
/**
| A CANDIDATE announcement whose reqtime
| is in the future.
|
*/
CANDIDATE_DELAYED = 0,
/**
| A CANDIDATE announcement that's not
| CANDIDATE_DELAYED or CANDIDATE_BEST.
|
*/
CANDIDATE_READY,
/**
| The best CANDIDATE for a given txhash;
| only if there is no REQUESTED announcement
| already for that txhash.
|
| The CANDIDATE_BEST is the highest-priority
| announcement among all CANDIDATE_READY
| (and _BEST) ones for that txhash.
|
*/
CANDIDATE_BEST,
/**
| A REQUESTED announcement.
|
*/
REQUESTED,
/**
| A COMPLETED announcement.
|
*/
COMPLETED,
}
impl TryFrom<u8> for State {
type Error = &'static str;
fn try_from(x: u8) -> Result<State, Self::Error> {
match x {
0 => Ok(State::CANDIDATE_DELAYED),
2 => Ok(State::CANDIDATE_READY),
3 => Ok(State::CANDIDATE_BEST),
4 => Ok(State::REQUESTED),
5 => Ok(State::COMPLETED),
_ => Err("bad input"),
}
}
}