connection_keep_alive() now returns KeepAlive (#899)

* connection_keep_alive() now returns Option<Instant>

* Use KeepAlive instead of Option<Instant>

core/src/protocols_handler/dummy.rs

@@ -19,7 +19,7 @@
 // DEALINGS IN THE SOFTWARE.
 
 use crate::{
-    protocols_handler::{ProtocolsHandler, ProtocolsHandlerEvent, ProtocolsHandlerUpgrErr},
+    protocols_handler::{KeepAlive, ProtocolsHandler, ProtocolsHandlerEvent, ProtocolsHandlerUpgrErr},
     upgrade::{
         InboundUpgrade,
         OutboundUpgrade,
@@ -89,7 +89,7 @@ where
     fn inject_inbound_closed(&mut self) {}
 
     #[inline]
-    fn connection_keep_alive(&self) -> bool { false }
+    fn connection_keep_alive(&self) -> KeepAlive { KeepAlive::Now }
 
     #[inline]
     fn shutdown(&mut self) {

core/src/protocols_handler/fuse.rs

@@ -20,7 +20,7 @@
 
 use crate::{
     either::EitherOutput,
-    protocols_handler::{ProtocolsHandler, ProtocolsHandlerEvent, ProtocolsHandlerUpgrErr},
+    protocols_handler::{KeepAlive, ProtocolsHandler, ProtocolsHandlerEvent, ProtocolsHandlerUpgrErr},
     upgrade::{
         DeniedUpgrade,
         EitherUpgrade,
@@ -124,11 +124,11 @@ where
     }
 
     #[inline]
-    fn connection_keep_alive(&self) -> bool {
+    fn connection_keep_alive(&self) -> KeepAlive {
         if let Some(inner) = self.inner.as_ref() {
             inner.connection_keep_alive()
         } else {
-            false
+            KeepAlive::Now
         }
     }
 

core/src/protocols_handler/map_in.rs

@@ -19,7 +19,7 @@
 // DEALINGS IN THE SOFTWARE.
 
 use crate::{
-    protocols_handler::{ProtocolsHandler, ProtocolsHandlerEvent, ProtocolsHandlerUpgrErr},
+    protocols_handler::{KeepAlive, ProtocolsHandler, ProtocolsHandlerEvent, ProtocolsHandlerUpgrErr},
     upgrade::{
         InboundUpgrade,
         OutboundUpgrade,
@@ -100,7 +100,7 @@ where
     }
 
     #[inline]
-    fn connection_keep_alive(&self) -> bool {
+    fn connection_keep_alive(&self) -> KeepAlive {
         self.inner.connection_keep_alive()
     }
 

core/src/protocols_handler/map_out.rs

@@ -19,7 +19,7 @@
 // DEALINGS IN THE SOFTWARE.
 
 use crate::{
-    protocols_handler::{ProtocolsHandler, ProtocolsHandlerEvent, ProtocolsHandlerUpgrErr},
+    protocols_handler::{KeepAlive, ProtocolsHandler, ProtocolsHandlerEvent, ProtocolsHandlerUpgrErr},
     upgrade::{
         InboundUpgrade,
         OutboundUpgrade,
@@ -95,7 +95,7 @@ where
     }
 
     #[inline]
-    fn connection_keep_alive(&self) -> bool {
+    fn connection_keep_alive(&self) -> KeepAlive {
         self.inner.connection_keep_alive()
     }
 

core/src/protocols_handler/mod.rs

@@ -40,7 +40,7 @@ use crate::upgrade::{
     UpgradeError,
 };
 use futures::prelude::*;
-use std::{error, fmt, time::Duration};
+use std::{error, fmt, time::Duration, time::Instant};
 use tokio_io::{AsyncRead, AsyncWrite};
 
 pub use self::dummy::DummyProtocolsHandler;
@@ -142,22 +142,23 @@ pub trait ProtocolsHandler {
     /// therefore no more inbound substreams will be produced.
     fn inject_inbound_closed(&mut self);
 
-    /// Returns whether the connection should be kept alive.
+    /// Returns until when the connection should be kept alive.
     ///
-    /// If returns `false`, that indicates that this connection is not important and the user may
-    /// invoke `shutdown()` if they think that they will no longer need the connection in the
-    /// future.
+    /// If returns `Until`, that indicates that this connection may invoke `shutdown()` after the
+    /// returned `Instant` has elapsed if they think that they will no longer need the connection
+    /// in the future. Returning `Forever` is equivalent to "infinite". Returning `Now` is
+    /// equivalent to `Until(Instant::now())`.
     ///
-    /// On the other hand, returning `true` is only an indication and doesn't mean that the user
+    /// On the other hand, the return value is only an indication and doesn't mean that the user
     /// will not call `shutdown()`.
     ///
-    /// When multiple `ProtocolsHandler` are combined together, they should use *OR* to merge the
-    /// result of this method.
+    /// When multiple `ProtocolsHandler` are combined together, they should use return the largest
+    /// value of the two, or `Forever` if either returns `Forever`.
     ///
     /// The result of this method should be checked every time `poll()` is invoked.
     ///
     /// After `shutdown()` is called, the result of this method doesn't matter anymore.
-    fn connection_keep_alive(&self) -> bool;
+    fn connection_keep_alive(&self) -> KeepAlive;
 
     /// Indicates to the node that it should shut down. After that, it is expected that `poll()`
     /// returns `Ready(ProtocolsHandlerEvent::Shutdown)` as soon as possible.
@@ -398,7 +399,7 @@ pub trait IntoProtocolsHandler {
     where
         Self: Sized,
     {
-        NodeHandlerWrapperBuilder::new(self, Duration::from_secs(10), Duration::from_secs(10), Duration::from_secs(5))
+        NodeHandlerWrapperBuilder::new(self, Duration::from_secs(10), Duration::from_secs(10))
     }
 }
 
@@ -412,3 +413,24 @@ where T: ProtocolsHandler
         self
     }
 }
+
+/// How long the connection should be kept alive.
+#[derive(Debug, Copy, Clone, PartialEq, Eq)]
+pub enum KeepAlive {
+    /// If nothing new happens, the connection should be closed at the given `Instant`.
+    Until(Instant),
+    /// Keep the connection alive.
+    Forever,
+    /// Close the connection as soon as possible.
+    Now,
+}
+
+impl KeepAlive {
+    /// Returns true for `Forever`, false otherwise.
+    pub fn is_forever(&self) -> bool {
+        match *self {
+            KeepAlive::Forever => true,
+            _ => false,
+        }
+    }
+}

core/src/protocols_handler/node_handler.rs

@@ -22,7 +22,7 @@ use crate::{
     PeerId,
     nodes::handled_node::{NodeHandler, NodeHandlerEndpoint, NodeHandlerEvent},
     nodes::handled_node_tasks::IntoNodeHandler,
-    protocols_handler::{ProtocolsHandler, IntoProtocolsHandler, ProtocolsHandlerEvent, ProtocolsHandlerUpgrErr},
+    protocols_handler::{KeepAlive, ProtocolsHandler, IntoProtocolsHandler, ProtocolsHandlerEvent, ProtocolsHandlerUpgrErr},
     upgrade::{
         self,
         OutboundUpgrade,
@@ -42,8 +42,6 @@ pub struct NodeHandlerWrapperBuilder<TIntoProtoHandler> {
     in_timeout: Duration,
     /// Timeout for outgoing substreams negotiation.
     out_timeout: Duration,
-    /// Time after which a useless connection will be closed.
-    useless_timeout: Duration,
 }
 
 impl<TIntoProtoHandler> NodeHandlerWrapperBuilder<TIntoProtoHandler>
@@ -52,12 +50,11 @@ where
 {
     /// Builds a `NodeHandlerWrapperBuilder`.
     #[inline]
-    pub(crate) fn new(handler: TIntoProtoHandler, in_timeout: Duration, out_timeout: Duration, useless_timeout: Duration) -> Self {
+    pub(crate) fn new(handler: TIntoProtoHandler, in_timeout: Duration, out_timeout: Duration) -> Self {
         NodeHandlerWrapperBuilder {
             handler,
             in_timeout,
             out_timeout,
-            useless_timeout,
         }
     }
 
@@ -75,14 +72,6 @@ where
         self
     }
 
-    /// Sets the timeout between the moment `connection_keep_alive()` returns `false` on the
-    /// `ProtocolsHandler`, and the moment the connection is closed.
-    #[inline]
-    pub fn with_useless_timeout(mut self, timeout: Duration) -> Self {
-        self.useless_timeout = timeout;
-        self
-    }
-
     /// Builds the `NodeHandlerWrapper`.
     #[deprecated(note = "Pass the NodeHandlerWrapperBuilder directly")]
     #[inline]
@@ -98,7 +87,6 @@ where
             queued_dial_upgrades: Vec::new(),
             unique_dial_upgrade_id: 0,
             connection_shutdown: None,
-            useless_timeout: self.useless_timeout,
         }
     }
 }
@@ -122,7 +110,6 @@ where
             queued_dial_upgrades: Vec::new(),
             unique_dial_upgrade_id: 0,
             connection_shutdown: None,
-            useless_timeout: self.useless_timeout,
         }
     }
 }
@@ -156,9 +143,6 @@ where
     /// When a connection has been deemed useless, will contain `Some` with a `Delay` to when it
     /// should be shut down.
     connection_shutdown: Option<Delay>,
-    ///  Timeout after which a useless connection is closed. When the `connection_shutdown` is set
-    /// to `Some`, this is the value that is being used.
-    useless_timeout: Duration,
 }
 
 impl<TProtoHandler> NodeHandler for NodeHandlerWrapper<TProtoHandler>
@@ -292,11 +276,11 @@ where
         loop {
             let poll_result = self.handler.poll()?;
 
-            if self.handler.connection_keep_alive() {
-                self.connection_shutdown = None;
-            } else if self.connection_shutdown.is_none() {
-                self.connection_shutdown = Some(Delay::new(Instant::now() + self.useless_timeout));
-            }
+            self.connection_shutdown = match self.handler.connection_keep_alive() {
+                KeepAlive::Until(expiration) => Some(Delay::new(expiration)),
+                KeepAlive::Now => Some(Delay::new(Instant::now())),
+                KeepAlive::Forever => None,
+            };
 
             match poll_result {
                 Async::Ready(ProtocolsHandlerEvent::Custom(event)) => {

core/src/protocols_handler/one_shot.rs

@@ -18,11 +18,11 @@
 // FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
 // DEALINGS IN THE SOFTWARE.
 
-use crate::protocols_handler::{ProtocolsHandler, ProtocolsHandlerEvent, ProtocolsHandlerUpgrErr};
+use crate::protocols_handler::{KeepAlive, ProtocolsHandler, ProtocolsHandlerEvent, ProtocolsHandlerUpgrErr};
 use crate::upgrade::{InboundUpgrade, OutboundUpgrade};
 use futures::prelude::*;
 use smallvec::SmallVec;
-use std::{error, marker::PhantomData};
+use std::{error, marker::PhantomData, time::Duration, time::Instant};
 use tokio_io::{AsyncRead, AsyncWrite};
 
 /// Implementation of `ProtocolsHandler` that opens a new substream for each individual message.
@@ -46,6 +46,10 @@ where TOutProto: OutboundUpgrade<TSubstream>
     dial_negotiated: u32,
     /// Maximum number of concurrent outbound substreams being opened. Value is never modified.
     max_dial_negotiated: u32,
+    /// Value to return from `connection_keep_alive`.
+    keep_alive: KeepAlive,
+    /// After the given duration has elapsed, an inactive connection will shutdown.
+    inactive_timeout: Duration,
     /// Pin the `TSubstream` generic.
     marker: PhantomData<TSubstream>,
 }
@@ -65,6 +69,8 @@ where TOutProto: OutboundUpgrade<TSubstream>
             dial_queue: SmallVec::new(),
             dial_negotiated: 0,
             max_dial_negotiated: 8,
+            keep_alive: KeepAlive::Forever,
+            inactive_timeout: Duration::from_secs(10),  // TODO: allow configuring
             marker: PhantomData,
         }
     }
@@ -96,6 +102,7 @@ where TOutProto: OutboundUpgrade<TSubstream>
     /// Opens an outbound substream with `upgrade`.
     #[inline]
     pub fn send_request(&mut self, upgrade: TOutProto) {
+        self.keep_alive = KeepAlive::Forever;
         self.dial_queue.push(upgrade);
     }
 }
@@ -143,6 +150,11 @@ where
             return;
         }
 
+        // If we're shutting down the connection for inactivity, reset the timeout.
+        if !self.keep_alive.is_forever() {
+            self.keep_alive = KeepAlive::Until(Instant::now() + self.inactive_timeout);
+        }
+
         self.events_out.push(out.into());
     }
 
@@ -154,6 +166,10 @@ where
     ) {
         self.dial_negotiated -= 1;
 
+        if self.dial_negotiated == 0 && self.dial_queue.is_empty() {
+            self.keep_alive = KeepAlive::Until(Instant::now() + self.inactive_timeout);
+        }
+
         if self.shutting_down {
             return;
         }
@@ -177,8 +193,8 @@ where
     fn inject_inbound_closed(&mut self) {}
 
     #[inline]
-    fn connection_keep_alive(&self) -> bool {
-        self.dial_negotiated != 0 || !self.dial_queue.is_empty()
+    fn connection_keep_alive(&self) -> KeepAlive {
+        self.keep_alive
     }
 
     #[inline]

core/src/protocols_handler/select.rs

@@ -23,6 +23,7 @@ use crate::{
     either::EitherError,
     either::EitherOutput,
     protocols_handler::{
+        KeepAlive,
         Fuse,
         IntoProtocolsHandler,
         ProtocolsHandler,
@@ -38,6 +39,7 @@ use crate::{
     }
 };
 use futures::prelude::*;
+use std::cmp;
 use tokio_io::{AsyncRead, AsyncWrite};
 
 /// Implementation of `IntoProtocolsHandler` that combines two protocols into one.
@@ -207,8 +209,12 @@ where
     }
 
     #[inline]
-    fn connection_keep_alive(&self) -> bool {
-        self.proto1.connection_keep_alive() || self.proto2.connection_keep_alive()
+    fn connection_keep_alive(&self) -> KeepAlive {
+        match (self.proto1.connection_keep_alive(), self.proto2.connection_keep_alive()) {
+            (KeepAlive::Forever, _) | (_, KeepAlive::Forever) => KeepAlive::Forever,
+            (a, KeepAlive::Now) | (KeepAlive::Now, a) => a,
+            (KeepAlive::Until(a), KeepAlive::Until(b)) => KeepAlive::Until(cmp::max(a, b)),
+        }
     }
 
     #[inline]