Codebase improvements (#258)

Author: fraillt

src/either.rs

@@ -1,3 +1,4 @@
+#[derive(Debug)]
 pub(crate) enum Either<L, R> {
     Left(L),
     Right(R),

src/lib.rs

@@ -37,6 +37,9 @@ mod throughput;
 #[cfg(feature = "tester")]
 pub use self::throughput::ThroughputMonitoring;
 
+#[cfg(test)]
+pub mod test_utils;
+
 pub use self::config::Config;
 pub use self::error::{ErrorKind, Result};
 pub use self::net::{LinkConditioner, Socket, SocketEvent};

src/net.rs

@@ -2,6 +2,8 @@
 //! You can think of the socket, connection management, congestion control.
 
 mod connection;
+mod connection_impl;
+mod connection_manager;
 mod events;
 mod link_conditioner;
 mod quality;
@@ -10,6 +12,8 @@ mod virtual_connection;
 
 pub mod constants;
 
+pub use self::connection::{Connection, ConnectionEventAddress, ConnectionMessenger};
+pub use self::connection_manager::{ConnectionManager, DatagramSocket};
 pub use self::events::SocketEvent;
 pub use self::link_conditioner::LinkConditioner;
 pub use self::quality::{NetworkQuality, RttMeasurer};

src/net/connection.rs

@@ -1,187 +1,73 @@
-pub use crate::net::{NetworkQuality, RttMeasurer, VirtualConnection};
-
-use crate::config::Config;
-use crate::either::Either::{self, Left, Right};
-use std::{
-    collections::HashMap,
-    net::SocketAddr,
-    time::{Duration, Instant},
-};
-
-/// Maintains a registry of active "connections". Essentially, when we receive a packet on the
-/// socket from a particular `SocketAddr`, we will track information about it here.
-#[derive(Debug)]
-pub struct ActiveConnections {
-    connections: HashMap<SocketAddr, VirtualConnection>,
-}
-
-impl ActiveConnections {
-    pub fn new() -> Self {
-        Self {
-            connections: HashMap::new(),
-        }
-    }
-
-    /// Try to get a `VirtualConnection` by address. If the connection does not exist, it will be
-    /// inserted and returned.
-    pub fn get_or_insert_connection(
-        &mut self,
-        address: SocketAddr,
-        config: &Config,
-        time: Instant,
-    ) -> &mut VirtualConnection {
-        self.connections
-            .entry(address)
-            .or_insert_with(|| VirtualConnection::new(address, config, time))
-    }
-
-    /// Try to get or create a [VirtualConnection] by address. If the connection does not exist, it will be
-    /// created and returned, but not inserted into the table of active connections.
-    pub(crate) fn get_or_create_connection(
-        &mut self,
-        address: SocketAddr,
-        config: &Config,
-        time: Instant,
-    ) -> Either<&mut VirtualConnection, VirtualConnection> {
-        if let Some(connection) = self.connections.get_mut(&address) {
-            Left(connection)
-        } else {
-            Right(VirtualConnection::new(address, config, time))
-        }
-    }
-
-    /// Removes the connection from `ActiveConnections` by socket address.
-    pub fn remove_connection(
-        &mut self,
-        address: &SocketAddr,
-    ) -> Option<(SocketAddr, VirtualConnection)> {
-        self.connections.remove_entry(address)
-    }
-
-    /// Check for and return `VirtualConnection`s which have been idling longer than `max_idle_time`.
-    pub fn idle_connections(&mut self, max_idle_time: Duration, time: Instant) -> Vec<SocketAddr> {
-        self.connections
-            .iter()
-            .filter(|(_, connection)| connection.last_heard(time) >= max_idle_time)
-            .map(|(address, _)| *address)
-            .collect()
-    }
-
-    /// Get a list of addresses of dead connections
-    pub fn dead_connections(&mut self) -> Vec<SocketAddr> {
-        self.connections
-            .iter()
-            .filter(|(_, connection)| connection.should_be_dropped())
-            .map(|(address, _)| *address)
-            .collect()
-    }
-
-    /// Check for and return `VirtualConnection`s which have not sent anything for a duration of at least `heartbeat_interval`.
-    pub fn heartbeat_required_connections(
-        &mut self,
-        heartbeat_interval: Duration,
-        time: Instant,
-    ) -> impl Iterator<Item = &mut VirtualConnection> {
-        self.connections
-            .iter_mut()
-            .filter(move |(_, connection)| connection.last_sent(time) >= heartbeat_interval)
-            .map(|(_, connection)| connection)
-    }
-
-    /// Returns true if the given connection exists.
-    pub fn exists(&self, address: &SocketAddr) -> bool {
-        self.connections.contains_key(&address)
-    }
-
-    /// Returns the number of connected clients.
-    #[cfg(test)]
-    pub(crate) fn count(&self) -> usize {
-        self.connections.len()
-    }
-}
-
-#[cfg(test)]
-mod tests {
-    use super::{ActiveConnections, Config};
-    use std::{
-        sync::Arc,
-        time::{Duration, Instant},
-    };
-
-    const ADDRESS: &str = "127.0.0.1:12345";
-
-    #[test]
-    fn connection_timed_out() {
-        let mut connections = ActiveConnections::new();
-        let config = Config::default();
-
-        let now = Instant::now();
-
-        // add 10 clients
-        for i in 0..10 {
-            connections.get_or_insert_connection(
-                format!("127.0.0.1:122{}", i).parse().unwrap(),
-                &config,
-                now,
-            );
-        }
-
-        assert_eq!(connections.count(), 10);
-
-        let wait = Duration::from_millis(200);
-
-        #[cfg(not(windows))]
-        let epsilon = Duration::from_nanos(1);
-        #[cfg(windows)]
-        let epsilon = Duration::from_millis(1);
-
-        let timed_out_connections = connections.idle_connections(wait, now + wait - epsilon);
-        assert_eq!(timed_out_connections.len(), 0);
-
-        let timed_out_connections = connections.idle_connections(wait, now + wait + epsilon);
-        assert_eq!(timed_out_connections.len(), 10);
-    }
-
-    #[test]
-    fn insert_connection() {
-        let mut connections = ActiveConnections::new();
-        let config = Config::default();
-
-        let address = ADDRESS.parse().unwrap();
-        connections.get_or_insert_connection(address, &config, Instant::now());
-        assert!(connections.connections.contains_key(&address));
-    }
-
-    #[test]
-    fn insert_existing_connection() {
-        let mut connections = ActiveConnections::new();
-        let config = Config::default();
-
-        let address = ADDRESS.parse().unwrap();
-        connections.get_or_insert_connection(address, &config, Instant::now());
-        assert!(connections.connections.contains_key(&address));
-        connections.get_or_insert_connection(address, &config, Instant::now());
-        assert!(connections.connections.contains_key(&address));
-    }
-
-    #[test]
-    fn remove_connection() {
-        let mut connections = ActiveConnections::new();
-        let config = Arc::new(Config::default());
-
-        let address = ADDRESS.parse().unwrap();
-        connections.get_or_insert_connection(address, &config, Instant::now());
-        assert!(connections.connections.contains_key(&address));
-        connections.remove_connection(&address);
-        assert!(!connections.connections.contains_key(&address));
-    }
-
-    #[test]
-    fn remove_non_existent_connection() {
-        let mut connections = ActiveConnections::new();
-
-        let address = &ADDRESS.parse().unwrap();
-        connections.remove_connection(address);
-        assert!(!connections.connections.contains_key(address));
-    }
-}
+use crate::config::Config;
+
+use std::{self, fmt::Debug, net::SocketAddr, time::Instant};
+
+/// Allows connection to send packet, send event and get global configuration.
+pub trait ConnectionMessenger<ReceiveEvent: Debug> {
+    /// Returns global configuration.
+    fn config(&self) -> &Config;
+
+    /// Sends a connection event.
+    fn send_event(&mut self, address: &SocketAddr, event: ReceiveEvent);
+    /// Sends a packet.
+    fn send_packet(&mut self, address: &SocketAddr, payload: &[u8]);
+}
+
+/// Returns an address of an event.
+/// This is used by a `ConnectionManager`, because it doesn't know anything about connection events.
+pub trait ConnectionEventAddress {
+    /// Returns event address
+    fn address(&self) -> SocketAddr;
+}
+
+/// Allows to implement actual connection.
+/// Defines a type of `Send` and `Receive` events, that will be used by a connection.
+pub trait Connection: Debug {
+    /// Defines a user event type.
+    type SendEvent: Debug + ConnectionEventAddress;
+    /// Defines a connection event type.
+    type ReceiveEvent: Debug + ConnectionEventAddress;
+
+    /// Creates new connection and initialize it by sending an connection event to the user.
+    /// * messenger - allows to send packets and events, also provides a config.
+    /// * address - defines a address that connection is associated with.
+    /// * time - creation time, used by connection, so that it doesn't get dropped immediately or send heartbeat packet.
+    /// * initial_data - if initiated by remote host, this will hold that a packet data.
+    fn create_connection(
+        messenger: &mut impl ConnectionMessenger<Self::ReceiveEvent>,
+        address: SocketAddr,
+        time: Instant,
+        initial_data: Option<&[u8]>,
+    ) -> Self;
+
+    /// Determines if the connection should be dropped due to its state.
+    fn should_drop(
+        &mut self,
+        messenger: &mut impl ConnectionMessenger<Self::ReceiveEvent>,
+        time: Instant,
+    ) -> bool;
+
+    /// Processes a received packet: parse it and emit an event.
+    fn process_packet(
+        &mut self,
+        messenger: &mut impl ConnectionMessenger<Self::ReceiveEvent>,
+        payload: &[u8],
+        time: Instant,
+    );
+
+    /// Processes a received event and send a packet.
+    fn process_event(
+        &mut self,
+        messenger: &mut impl ConnectionMessenger<Self::ReceiveEvent>,
+        event: Self::SendEvent,
+        time: Instant,
+    );
+
+    /// Processes various connection-related tasks: resend dropped packets, send heartbeat packet, etc...
+    /// This function gets called frequently.
+    fn update(
+        &mut self,
+        messenger: &mut impl ConnectionMessenger<Self::ReceiveEvent>,
+        time: Instant,
+    );
+}