User-driven wakeups

little_raft/src/cluster.rs

@@ -1,5 +1,4 @@
 use crate::{message::Message, state_machine::StateMachineTransition};
-use std::time::Duration;
 
 // Cluster provides the means of communication of a replica with the rest of the
 // cluster and the user.
@@ -9,15 +8,15 @@ where
 {
     // This function is used to deliver messages to target replicas. The
     // algorithm assumes that send can silently fail.
-    fn send(&self, to_id: usize, message: Message<T>);
-    // This function is used to received messages for the replicas. This
-    // function must block until timeout expires or a message is received,
-    // whichever comes first.
-    fn receive_timeout(&self, timeout: Duration) -> Option<Message<T>>;
+    fn send(&mut self, to_id: usize, message: Message<T>);
+    // This function is used to received messages for the replicas. If there are
+    // no messages pending, the function should return immediately.
+    fn receive(&mut self) -> Vec<Message<T>>;
     // This function is used to receive actions from the user that the
     // distributed state machine needs to replicate and apply. All replicas poll
     // this function periodically but only Leaders merit the return value.
     // Non-Leaders ignore the return value of get_action.
-    fn get_pending_transitions(&self) -> Vec<T>;
-    fn register_leader_change(&mut self, leader_id: Option<usize>);
+    fn get_pending_transitions(&mut self) -> Vec<T>;
+
+    fn halt(&self) -> bool;
 }

little_raft/src/lib.rs

@@ -1,5 +1,5 @@
 pub mod cluster;
-mod heartbeat_timer;
 pub mod message;
 pub mod replica;
 pub mod state_machine;
+mod timer;

little_raft/src/message.rs

@@ -4,7 +4,7 @@ use crate::state_machine::StateMachineTransition;
 // Entry describes a user-defined transition of the distributed state machine.
 // It has some associated metadata, namely the term when the entry was created
 // and its index in the log.
-#[derive(Clone, Debug)]
+#[derive(Clone, Debug, Copy, PartialEq, Eq, PartialOrd)]
 pub struct Entry<T>
 where
     T: StateMachineTransition,
@@ -16,7 +16,7 @@ where
 
 // Message describes messages that the replicas pass between each other to
 // achieve consensus on the distributed state machine.
-#[derive(Debug)]
+#[derive(Debug, Clone, PartialEq, Eq, PartialOrd)]
 pub enum Message<T>
 where
     T: StateMachineTransition,