Update the set of unique signatures when loading an existing log.

src/accountant.rs

@@ -3,9 +3,9 @@
 //! transfer funds to other users.
 
 use log::{hash, Entry, Sha256Hash};
-use event::{get_pubkey, sign_transaction_data, Event, PublicKey, Signature};
+use event::{get_pubkey, sign_transaction_data, verify_event, Event, PublicKey, Signature};
 use genesis::Genesis;
-use historian::Historian;
+use historian::{reserve_signature, Historian};
 use ring::signature::Ed25519KeyPair;
 use std::sync::mpsc::SendError;
 use std::collections::HashMap;
@@ -37,7 +37,7 @@ impl Accountant {
             balances: HashMap::new(),
             last_id: start_hash,
         };
-        for (i, event) in gen.create_events().into_iter().enumerate() {
+        for (i, event) in gen.create_events().iter().enumerate() {
             acc.process_verified_event(event, i < 2).unwrap();
         }
         acc
@@ -61,30 +61,35 @@ impl Accountant {
     }
 
     pub fn process_event(self: &mut Self, event: Event<u64>) -> Result<()> {
-        if !self.historian.verify_event(&event) {
+        if !verify_event(&event) {
             return Err(AccountingError::InvalidEvent);
         }
-        self.process_verified_event(event, false)
-    }
 
-    fn process_verified_event(
+        if let Event::Transaction { from, data, .. } = event {
-        self: &mut Self,
-        event: Event<u64>,
-        allow_deposits: bool,
-    ) -> Result<()> {
-        match event {
-            Event::Tick => Ok(()),
-            Event::Transaction { from, to, data, .. } => {
-                if !Self::is_deposit(allow_deposits, &from, &to) {
             if self.get_balance(&from).unwrap_or(0) < data {
                 return Err(AccountingError::InsufficientFunds);
             }
         }
 
+        self.process_verified_event(&event, false)?;
+
         if let Err(SendError(_)) = self.historian.sender.send(event) {
             return Err(AccountingError::SendError);
         }
 
+        Ok(())
+    }
+
+    fn process_verified_event(
+        self: &mut Self,
+        event: &Event<u64>,
+        allow_deposits: bool,
+    ) -> Result<()> {
+        if !reserve_signature(&mut self.historian.signatures, event) {
+            return Err(AccountingError::InvalidEvent);
+        }
+
+        if let Event::Transaction { from, to, data, .. } = *event {
             if !Self::is_deposit(allow_deposits, &from, &to) {
                 if let Some(x) = self.balances.get_mut(&from) {
                     *x -= data;
@@ -98,10 +103,9 @@ impl Accountant {
             } else {
                 self.balances.insert(to, data);
             }
+        }
         Ok(())
     }
-        }
-    }
 
     pub fn transfer(
         self: &mut Self,

src/historian.rs

@@ -1,16 +1,15 @@
 //! The `historian` crate provides a microservice for generating a Proof-of-History.
 //! It manages a thread containing a Proof-of-History Logger.
 
-use std::thread::JoinHandle;
+use std::thread::{spawn, JoinHandle};
 use std::collections::HashSet;
 use std::sync::mpsc::{sync_channel, Receiver, SyncSender};
 use std::time::Instant;
 use log::{hash, Entry, Sha256Hash};
-use logger::{verify_event_and_reserve_signature, ExitReason, Logger};
+use logger::{ExitReason, Logger};
-use event::{Event, Signature};
+use event::{get_signature, Event, Signature};
 use serde::Serialize;
 use std::fmt::Debug;
-use std::thread;
 
 pub struct Historian<T> {
     pub sender: SyncSender<Event<T>>,
@@ -34,10 +33,6 @@ impl<T: 'static + Serialize + Clone + Debug + Send> Historian<T> {
         }
     }
 
-    pub fn verify_event(self: &mut Self, event: &Event<T>) -> bool {
-        return verify_event_and_reserve_signature(&mut self.signatures, event);
-    }
-
     /// A background thread that will continue tagging received Event messages and
     /// sending back Entry messages until either the receiver or sender channel is closed.
     fn create_logger(
@@ -46,7 +41,7 @@ impl<T: 'static + Serialize + Clone + Debug + Send> Historian<T> {
         receiver: Receiver<Event<T>>,
         sender: SyncSender<Entry<T>>,
     ) -> JoinHandle<(Entry<T>, ExitReason)> {
-        thread::spawn(move || {
+        spawn(move || {
             let mut logger = Logger::new(receiver, sender, start_hash);
             let now = Instant::now();
             loop {
@@ -60,6 +55,16 @@ impl<T: 'static + Serialize + Clone + Debug + Send> Historian<T> {
     }
 }
 
+pub fn reserve_signature<T>(sigs: &mut HashSet<Signature>, event: &Event<T>) -> bool {
+    if let Some(sig) = get_signature(&event) {
+        if sigs.contains(&sig) {
+            return false;
+        }
+        sigs.insert(sig);
+    }
+    true
+}
+
 #[cfg(test)]
 mod tests {
     use super::*;
@@ -104,6 +109,18 @@ mod tests {
         );
     }
 
+    #[test]
+    fn test_duplicate_event_signature() {
+        let keypair = generate_keypair();
+        let to = get_pubkey(&keypair);
+        let data = b"hello, world";
+        let sig = sign_claim_data(&data, &keypair);
+        let event0 = Event::new_claim(to, &data, sig);
+        let mut sigs = HashSet::new();
+        assert!(reserve_signature(&mut sigs, &event0));
+        assert!(!reserve_signature(&mut sigs, &event0));
+    }
+
     #[test]
     fn test_ticking_historian() {
         let zero = Sha256Hash::default();

src/logger.rs

@@ -5,11 +5,10 @@
 //! Event, the latest hash, and the number of hashes since the last event.
 //! The resulting stream of entries represents ordered events in time.
 
-use std::collections::HashSet;
 use std::sync::mpsc::{Receiver, SyncSender, TryRecvError};
 use std::time::{Duration, Instant};
 use log::{create_entry_mut, Entry, Sha256Hash};
-use event::{get_signature, verify_event, Event, Signature};
+use event::Event;
 use serde::Serialize;
 use std::fmt::Debug;
 
@@ -27,22 +26,6 @@ pub struct Logger<T> {
     pub num_ticks: u64,
 }
 
-pub fn verify_event_and_reserve_signature<T: Serialize>(
-    signatures: &mut HashSet<Signature>,
-    event: &Event<T>,
-) -> bool {
-    if !verify_event(&event) {
-        return false;
-    }
-    if let Some(sig) = get_signature(&event) {
-        if signatures.contains(&sig) {
-            return false;
-        }
-        signatures.insert(sig);
-    }
-    true
-}
-
 impl<T: Serialize + Clone + Debug> Logger<T> {
     pub fn new(
         receiver: Receiver<Event<T>>,
@@ -111,21 +94,7 @@ mod tests {
         let keypair = generate_keypair();
         let sig = sign_claim_data(&hash(b"hello, world"), &keypair);
         let event0 = Event::new_claim(get_pubkey(&keypair), hash(b"goodbye cruel world"), sig);
-        let mut sigs = HashSet::new();
+        assert!(!verify_event(&event0));
-        assert!(!verify_event_and_reserve_signature(&mut sigs, &event0));
-        assert!(!sigs.contains(&sig));
-    }
-
-    #[test]
-    fn test_duplicate_event_signature() {
-        let keypair = generate_keypair();
-        let to = get_pubkey(&keypair);
-        let data = &hash(b"hello, world");
-        let sig = sign_claim_data(data, &keypair);
-        let event0 = Event::new_claim(to, data, sig);
-        let mut sigs = HashSet::new();
-        assert!(verify_event_and_reserve_signature(&mut sigs, &event0));
-        assert!(!verify_event_and_reserve_signature(&mut sigs, &event0));
     }
 
     fn run_genesis(gen: Genesis) -> Vec<Entry<u64>> {