aquatic_ws: clean torrent state periodically

aquatic_ws/src/lib/tasks.rs

@@ -0,0 +1,20 @@
+use std::time::Instant;
+
+use crate::common::*;
+
+
+pub fn clean_torrents(state: &State){
+    let mut torrents = state.torrents.lock();
+
+    let now = Instant::now();
+
+    torrents.retain(|_, torrent_data| {
+        torrent_data.peers.retain(|_, peer| {
+            peer.valid_until.0 >= now
+        });
+
+        !torrent_data.peers.is_empty()
+    });
+
+    torrents.shrink_to_fit();
+}