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use std::collections::HashMap;
use std::sync::Mutex;
use serde::{Deserialize, Serialize};
use tokio::sync::broadcast;
use crate::k2v::history_table::*;
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 {
item_subscriptions: Mutex<HashMap<PollKey, broadcast::Sender<K2VItem>>>,
range_subscriptions: Mutex<HashMap<PollRange, broadcast::Sender<K2VHistoryEntry>>>,
}
impl SubscriptionManager {
pub fn new() -> Self {
Self::default()
}
// ---- simple item polling ----
pub fn subscribe_item(&self, key: &PollKey) -> broadcast::Receiver<K2VItem> {
let mut subs = self.item_subscriptions.lock().unwrap();
if let Some(s) = subs.get(key) {
s.subscribe()
} else {
let (tx, rx) = broadcast::channel(8);
subs.insert(key.clone(), tx);
rx
}
}
pub fn notify_item(&self, item: &K2VItem) {
let key = PollKey {
partition: item.partition.clone(),
sort_key: item.sort_key.clone(),
};
let mut subs = self.item_subscriptions.lock().unwrap();
if let Some(s) = subs.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)
subs.remove(&key);
}
}
}
// ---- range polling ----
pub fn subscribe_range(&self, key: &PollRange) -> broadcast::Receiver<K2VHistoryEntry> {
let mut subs = self.range_subscriptions.lock().unwrap();
if let Some(s) = subs.get(key) {
s.subscribe()
} else {
let (tx, rx) = broadcast::channel(8);
subs.insert(key.clone(), tx);
rx
}
}
pub fn notify_range(&self, entry: &K2VHistoryEntry) {
let mut subs = self.range_subscriptions.lock().unwrap();
let mut dead_subs = vec![];
for (sub, chan) in subs.iter() {
if sub.matches(&entry) {
if chan.send(entry.clone()).is_err() {
dead_subs.push(sub.clone());
}
} else if chan.receiver_count() == 0 {
dead_subs.push(sub.clone());
}
}
for sub in dead_subs.iter() {
subs.remove(sub);
}
}
}
impl PollRange {
fn matches(&self, entry: &K2VHistoryEntry) -> bool {
entry.ins_item.partition == self.partition
&& self
.prefix
.as_ref()
.map(|x| entry.ins_item.sort_key.starts_with(x))
.unwrap_or(true)
&& self
.start
.as_ref()
.map(|x| entry.ins_item.sort_key >= *x)
.unwrap_or(true)
&& self
.end
.as_ref()
.map(|x| entry.ins_item.sort_key < *x)
.unwrap_or(true)
}
}
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