garage/src/model/k2v/sub.rs

108 lines
2.6 KiB
Rust
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2023-01-10 09:30:59 +00:00
use std::collections::HashMap;
use std::sync::Mutex;
use serde::{Deserialize, Serialize};
use tokio::sync::broadcast;
use crate::k2v::item_table::*;
#[derive(Debug, Hash, Clone, PartialEq, Eq, Serialize, Deserialize)]
pub struct PollKey {
pub partition: K2VItemPartition,
pub sort_key: String,
}
#[derive(Debug, Hash, Clone, PartialEq, Eq, Serialize, Deserialize)]
pub struct PollRange {
pub partition: K2VItemPartition,
pub prefix: Option<String>,
pub start: Option<String>,
pub end: Option<String>,
}
#[derive(Default)]
pub struct SubscriptionManager(Mutex<SubscriptionManagerInner>);
#[derive(Default)]
pub struct SubscriptionManagerInner {
item_subscriptions: HashMap<PollKey, broadcast::Sender<K2VItem>>,
range_subscriptions: HashMap<PollRange, broadcast::Sender<K2VItem>>,
}
impl SubscriptionManager {
pub fn new() -> Self {
Self::default()
}
pub fn subscribe_item(&self, key: &PollKey) -> broadcast::Receiver<K2VItem> {
let mut inner = self.0.lock().unwrap();
if let Some(s) = inner.item_subscriptions.get(key) {
s.subscribe()
} else {
let (tx, rx) = broadcast::channel(8);
inner.item_subscriptions.insert(key.clone(), tx);
rx
}
}
pub fn subscribe_range(&self, key: &PollRange) -> broadcast::Receiver<K2VItem> {
let mut inner = self.0.lock().unwrap();
if let Some(s) = inner.range_subscriptions.get(key) {
s.subscribe()
} else {
let (tx, rx) = broadcast::channel(8);
inner.range_subscriptions.insert(key.clone(), tx);
rx
}
}
pub fn notify(&self, item: &K2VItem) {
let mut inner = self.0.lock().unwrap();
// 1. Notify single item subscribers,
// removing subscriptions with no more listeners if any
let key = PollKey {
partition: item.partition.clone(),
sort_key: item.sort_key.clone(),
};
if let Some(s) = inner.item_subscriptions.get(&key) {
if s.send(item.clone()).is_err() {
// no more subscribers, remove channel from here
// (we will re-create it later if we need to subscribe again)
inner.item_subscriptions.remove(&key);
}
}
// 2. Notify range subscribers,
// removing subscriptions with no more listeners if any
inner.range_subscriptions.retain(|sub, chan| {
if sub.matches(&item) {
chan.send(item.clone()).is_ok()
} else {
chan.receiver_count() != 0
}
});
}
}
impl PollRange {
fn matches(&self, item: &K2VItem) -> bool {
item.partition == self.partition
&& self
.prefix
.as_ref()
.map(|x| item.sort_key.starts_with(x))
.unwrap_or(true)
&& self
.start
.as_ref()
.map(|x| item.sort_key >= *x)
.unwrap_or(true)
&& self
.end
.as_ref()
.map(|x| item.sort_key < *x)
.unwrap_or(true)
}
}