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use super::{
event::{Created, Deleted, Event},
Channel, Id,
};
use crate::event::{Instant, ResumePoint, Sequence};
#[derive(Clone, Debug, Eq, PartialEq)]
pub struct History {
pub channel: Channel,
pub created: Instant,
pub deleted: Option<Instant>,
}
// State interface
impl History {
pub fn id(&self) -> &Id {
&self.channel.id
}
// Snapshot of this channel as it was when created. (Note to the future: it's
// okay if this returns a redacted or modified version of the channel. If we
// implement renames by redacting the original name, then this should return the
// renamed channel, not the original, even if that's not how it was "as
// created.")
pub fn as_created(&self) -> Channel {
self.channel.clone()
}
pub fn as_of(&self, resume_point: impl Into<ResumePoint>) -> Option<Channel> {
self.events()
.filter(Sequence::up_to(resume_point.into()))
.collect()
}
}
// Event factories
impl History {
pub fn events(&self) -> impl Iterator<Item = Event> {
[self.created()].into_iter().chain(self.deleted())
}
fn created(&self) -> Event {
Event {
instant: self.created,
kind: Created {
channel: self.channel.clone(),
}
.into(),
}
}
fn deleted(&self) -> Option<Event> {
self.deleted.map(|instant| Event {
instant,
kind: Deleted {
id: self.channel.id.clone(),
}
.into(),
})
}
}
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