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//! Implements a RangeSeenMarker, a data type used in the PollRange API
//! to indicate which items in the range have already been seen
//! and which have not been seen yet.
//!
//! It consists of a vector clock that indicates that for each node,
//! all items produced by that node with timestamps <= the value in the
//! vector clock has been seen, as well as a set of causal contexts for
//! individual items.
use std::collections::BTreeMap;
use serde::{Deserialize, Serialize};
use garage_util::data::Uuid;
use garage_util::encode::{nonversioned_decode, nonversioned_encode};
use garage_util::error::{Error, OkOrMessage};
use crate::k2v::causality::*;
use crate::k2v::item_table::*;
#[derive(Debug, Serialize, Deserialize, Default)]
pub struct RangeSeenMarker {
vector_clock: VectorClock,
items: BTreeMap<String, VectorClock>,
}
impl RangeSeenMarker {
pub fn new() -> Self {
Self::default()
}
pub fn mark_seen_node_items<'a, I: IntoIterator<Item = &'a K2VItem>>(
&mut self,
node: Uuid,
items: I,
) {
let node = make_node_id(node);
for item in items.into_iter() {
let cc = item.causal_context();
if let Some(ts) = cc.vector_clock.get(&node) {
let ent = self.vector_clock.entry(node).or_insert(0);
*ent = std::cmp::max(*ent, *ts);
}
if vclock_gt(&cc.vector_clock, &self.vector_clock) {
match self.items.get_mut(&item.sort_key) {
None => {
self.items.insert(item.sort_key.clone(), cc.vector_clock);
}
Some(ent) => *ent = vclock_max(&ent, &cc.vector_clock),
}
}
}
}
pub fn canonicalize(&mut self) {
let self_vc = &self.vector_clock;
self.items.retain(|_sk, vc| vclock_gt(&vc, self_vc))
}
pub fn encode(&mut self) -> Result<String, Error> {
self.canonicalize();
let bytes = nonversioned_encode(&self)?;
let bytes = zstd::stream::encode_all(&mut &bytes[..], zstd::DEFAULT_COMPRESSION_LEVEL)?;
Ok(base64::encode(&bytes))
}
pub fn decode(s: &str) -> Result<Self, Error> {
let bytes = base64::decode(&s).ok_or_message("invalid base64")?;
let bytes = zstd::stream::decode_all(&mut &bytes[..])?;
Ok(nonversioned_decode(&bytes)?)
}
pub fn is_new_item(&self, item: &K2VItem) -> bool {
let cc = item.causal_context();
vclock_gt(&cc.vector_clock, &self.vector_clock)
&& self
.items
.get(&item.sort_key)
.map(|vc| vclock_gt(&cc.vector_clock, &vc))
.unwrap_or(true)
}
}
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