http_private: do more work on request worker

aquatic_http_private/src/workers/request.rs

@@ -1,10 +1,136 @@
-use tokio::sync::mpsc::Receiver;
+use std::cell::RefCell;
+use std::net::{Ipv4Addr, Ipv6Addr};
+use std::rc::Rc;
+use std::time::Instant;
 
-use aquatic_http_protocol::response::{FailureResponse, Response};
+use tokio::sync::mpsc::Receiver;
+use tokio::task::LocalSet;
+use tokio::time;
+
+use aquatic_common::{AmortizedIndexMap, CanonicalSocketAddr, ValidUntil};
+use aquatic_http_protocol::common::{AnnounceEvent, InfoHash, PeerId};
+use aquatic_http_protocol::request::AnnounceRequest;
+use aquatic_http_protocol::response::{FailureResponse, Response, ResponsePeer};
 
 use crate::common::ChannelAnnounceRequest;
 use crate::config::Config;
 
+pub trait Ip: ::std::fmt::Debug + Copy + Eq + ::std::hash::Hash {}
+
+impl Ip for Ipv4Addr {}
+impl Ip for Ipv6Addr {}
+
+#[derive(PartialEq, Eq, Clone, Copy, Debug)]
+pub enum PeerStatus {
+    Seeding,
+    Leeching,
+    Stopped,
+}
+
+impl PeerStatus {
+    /// Determine peer status from announce event and number of bytes left.
+    ///
+    /// Likely, the last branch will be taken most of the time.
+    #[inline]
+    pub fn from_event_and_bytes_left(event: AnnounceEvent, opt_bytes_left: Option<usize>) -> Self {
+        if let AnnounceEvent::Stopped = event {
+            Self::Stopped
+        } else if let Some(0) = opt_bytes_left {
+            Self::Seeding
+        } else {
+            Self::Leeching
+        }
+    }
+}
+
+#[derive(Debug, Clone, Copy)]
+pub struct Peer<I: Ip> {
+    pub ip_address: I,
+    pub port: u16,
+    pub status: PeerStatus,
+    pub valid_until: ValidUntil,
+}
+
+impl<I: Ip> Peer<I> {
+    pub fn to_response_peer(&self) -> ResponsePeer<I> {
+        ResponsePeer {
+            ip_address: self.ip_address,
+            port: self.port,
+        }
+    }
+}
+
+#[derive(Debug, Clone, PartialEq, Eq, Hash)]
+pub struct PeerMapKey<I: Ip> {
+    pub peer_id: PeerId,
+    pub ip: I,
+}
+
+pub type PeerMap<I> = AmortizedIndexMap<PeerMapKey<I>, Peer<I>>;
+
+pub struct TorrentData<I: Ip> {
+    pub peers: PeerMap<I>,
+    pub num_seeders: usize,
+    pub num_leechers: usize,
+}
+
+impl<I: Ip> Default for TorrentData<I> {
+    #[inline]
+    fn default() -> Self {
+        Self {
+            peers: Default::default(),
+            num_seeders: 0,
+            num_leechers: 0,
+        }
+    }
+}
+
+pub type TorrentMap<I> = AmortizedIndexMap<InfoHash, TorrentData<I>>;
+
+#[derive(Default)]
+pub struct TorrentMaps {
+    pub ipv4: TorrentMap<Ipv4Addr>,
+    pub ipv6: TorrentMap<Ipv6Addr>,
+}
+
+impl TorrentMaps {
+    pub fn clean(&mut self) {
+        Self::clean_torrent_map(&mut self.ipv4);
+        Self::clean_torrent_map(&mut self.ipv6);
+    }
+
+    fn clean_torrent_map<I: Ip>(torrent_map: &mut TorrentMap<I>) {
+        let now = Instant::now();
+
+        torrent_map.retain(|_, torrent_data| {
+            let num_seeders = &mut torrent_data.num_seeders;
+            let num_leechers = &mut torrent_data.num_leechers;
+
+            torrent_data.peers.retain(|_, peer| {
+                let keep = peer.valid_until.0 >= now;
+
+                if !keep {
+                    match peer.status {
+                        PeerStatus::Seeding => {
+                            *num_seeders -= 1;
+                        }
+                        PeerStatus::Leeching => {
+                            *num_leechers -= 1;
+                        }
+                        _ => (),
+                    };
+                }
+
+                keep
+            });
+
+            !torrent_data.peers.is_empty()
+        });
+
+        torrent_map.shrink_to_fit();
+    }
+}
+
 pub fn run_request_worker(
     config: Config,
     request_receiver: Receiver<ChannelAnnounceRequest>,
@@ -22,18 +148,47 @@ async fn run_inner(
     config: Config,
     mut request_receiver: Receiver<ChannelAnnounceRequest>,
 ) -> anyhow::Result<()> {
+    let torrents = Rc::new(RefCell::new(TorrentMaps::default()));
+
+    LocalSet::new().spawn_local(periodically_clean_torrents(
+        config.clone(),
+        torrents.clone(),
+    ));
+
     loop {
         let request = request_receiver
             .recv()
             .await
             .ok_or_else(|| anyhow::anyhow!("request channel closed"))?;
 
-        println!("{:?}", request);
+        let response = handle_announce_request(
+            &config,
+            &torrents,
+            request.source_addr,
+            request.request.into(),
+        );
 
-        let _ = request
-            .response_sender
-            .send(Response::Failure(FailureResponse::new(
-                "successful actually",
-            )));
+        let _ = request.response_sender.send(response);
+    }
+}
+
+fn handle_announce_request(
+    config: &Config,
+    torrents: &Rc<RefCell<TorrentMaps>>,
+    source_addr: CanonicalSocketAddr,
+    request: AnnounceRequest,
+) -> Response {
+    Response::Failure(FailureResponse::new("actually successful"))
+}
+
+async fn periodically_clean_torrents(config: Config, torrents: Rc<RefCell<TorrentMaps>>) {
+    let mut interval = time::interval(time::Duration::from_secs(
+        config.cleaning.torrent_cleaning_interval,
+    ));
+
+    loop {
+        interval.tick().await;
+
+        torrents.borrow_mut().clean();
     }
 }