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use async_trait::async_trait;
use futures::io::AsyncRead;
use crate::Identifier;
#[async_trait(?Send)]
pub trait LogEntry: 'static + Clone + std::fmt::Debug + Send + Sync + Unpin {
type Id: Identifier;
type Reader: std::io::Read;
/// Deserializes log entry that was previously serialized using
/// `to_reader()`.
///
/// While implementations need not detect arbitrary data corruption, they
/// must not panic.
async fn from_reader<R: AsyncRead + Unpin>(read: R) -> Result<Self, crate::error::BoxError>;
/// Number of bytes the result of `to_reader()` will emit.
fn size(&self) -> usize;
/// Serializes the log entry to enable snapshots.
///
/// `LogEntry::from_reader(e.to_reader())` must yield an equivalent log
/// entry.
fn to_reader(&self) -> Self::Reader;
/// Returns a unique identifier for the log entry.
///
/// Identifiers need only be unique within the rough timeframe of them being
/// appended to the distributed log. That notwithstanding it is recommended
/// that UUIDs or some other "universally unique" identifier are used.
fn id(&self) -> Self::Id;
}
#[derive(Debug)]
pub struct LogKeeping {
pub(crate) logs_kept: usize,
pub(crate) entry_limit: usize,
}
impl Default for LogKeeping {
fn default() -> Self {
Self {
logs_kept: 5,
entry_limit: 1024,
}
}
}