Make conditions explicit in races

And boot recursive spending plans. That path required heap allocations.
Since we don't have a need for this generality right now, reduce the
language to the smallest one that can pass our test suite.

src/accountant.rs

@@ -5,7 +5,7 @@
 use hash::Hash;
 use entry::Entry;
 use event::Event;
-use plan::{Action, Plan};
+use plan::{Action, Plan, PlanEvent};
 use transaction::Transaction;
 use signature::{KeyPair, PublicKey, Signature};
 use mint::Mint;
@@ -141,7 +141,7 @@ impl Accountant {
         }
 
         let mut plan = tr.plan.clone();
-        let actionable = plan.process_verified_timestamp(self.last_time);
+        let actionable = plan.process_event(PlanEvent::Timestamp(self.last_time));
 
         if !actionable {
             self.pending.insert(tr.sig, plan);
@@ -154,7 +154,7 @@ impl Accountant {
 
     fn process_verified_sig(&mut self, from: PublicKey, tx_sig: Signature) -> Result<()> {
         let actionable = if let Some(plan) = self.pending.get_mut(&tx_sig) {
-            plan.process_verified_sig(from)
+            plan.process_event(PlanEvent::Signature(from))
         } else {
             false
         };
@@ -186,7 +186,7 @@ impl Accountant {
         // Check to see if any timelocked transactions can be completed.
         let mut completed = vec![];
         for (key, plan) in &mut self.pending {
-            if plan.process_verified_timestamp(self.last_time) {
+            if plan.process_event(PlanEvent::Timestamp(self.last_time)) {
                 completed.push(key.clone());
             }
         }

src/plan.rs

@@ -10,6 +10,23 @@ pub enum Condition {
     Signature(PublicKey),
 }
 
+pub enum PlanEvent {
+    Timestamp(DateTime<Utc>),
+    Signature(PublicKey),
+}
+
+impl Condition {
+    pub fn is_satisfied(&self, event: &PlanEvent) -> bool {
+        match (self, event) {
+            (&Condition::Signature(ref pubkey), &PlanEvent::Signature(ref from)) => pubkey == from,
+            (&Condition::Timestamp(ref dt), &PlanEvent::Timestamp(ref last_time)) => {
+                dt <= last_time
+            }
+            _ => false,
+        }
+    }
+}
+
 #[derive(Serialize, Deserialize, Debug, PartialEq, Eq, Clone)]
 pub enum Action {
     Pay(Payment),
@@ -18,7 +35,7 @@ pub enum Action {
 impl Action {
     pub fn spendable(&self) -> i64 {
         match *self {
-            Action::Pay(ref payment) => payment.asset.clone(),
+            Action::Pay(ref payment) => payment.asset,
         }
     }
 }
@@ -32,90 +49,41 @@ pub struct Payment {
 #[derive(Serialize, Deserialize, Debug, PartialEq, Eq, Clone)]
 pub enum Plan {
     Action(Action),
-    After(Condition, Box<Plan>),
-    Race(Box<Plan>, Box<Plan>),
+    After(Condition, Action),
+    Race((Condition, Action), (Condition, Action)),
 }
 
 impl Plan {
     pub fn verify(&self, spendable_assets: i64) -> bool {
         match *self {
             Plan::Action(ref action) => action.spendable() == spendable_assets,
-            Plan::Race(ref plan_a, ref plan_b) => {
-                plan_a.verify(spendable_assets) && plan_b.verify(spendable_assets)
+            Plan::After(_, ref action) => action.spendable() == spendable_assets,
+            Plan::Race(ref a, ref b) => {
+                a.1.spendable() == spendable_assets && b.1.spendable() == spendable_assets
             }
-            Plan::After(_, ref plan) => plan.verify(spendable_assets),
         }
     }
 
-    pub fn run_race(&mut self) -> bool {
-        let new_plan = if let Plan::Race(ref a, ref b) = *self {
-            if let Plan::Action(_) = **a {
-                Some((**a).clone())
-            } else if let Plan::Action(_) = **b {
-                Some((**b).clone())
-            } else {
-                None
-            }
-        } else {
-            None
-        };
-
-        if let Some(plan) = new_plan {
-            mem::replace(self, plan);
-            true
-        } else {
-            false
-        }
-    }
-
-    pub fn process_verified_sig(&mut self, from: PublicKey) -> bool {
-        let mut new_plan = None;
+    pub fn process_event(&mut self, event: PlanEvent) -> bool {
+        let mut new_action = None;
         match *self {
             Plan::Action(_) => return true,
-            Plan::Race(ref mut plan_a, ref mut plan_b) => {
-                plan_a.process_verified_sig(from);
-                plan_b.process_verified_sig(from);
-            }
-            Plan::After(Condition::Signature(pubkey), ref plan) => {
-                if from == pubkey {
-                    new_plan = Some((**plan).clone());
+            Plan::After(ref cond, ref action) => {
+                if cond.is_satisfied(&event) {
+                    new_action = Some(action.clone());
                 }
             }
-            _ => (),
-        }
-        if self.run_race() {
-            return true;
-        }
-
-        if let Some(plan) = new_plan {
-            mem::replace(self, plan);
-            true
-        } else {
-            false
-        }
-    }
-
-    pub fn process_verified_timestamp(&mut self, last_time: DateTime<Utc>) -> bool {
-        let mut new_plan = None;
-        match *self {
-            Plan::Action(_) => return true,
-            Plan::Race(ref mut plan_a, ref mut plan_b) => {
-                plan_a.process_verified_timestamp(last_time);
-                plan_b.process_verified_timestamp(last_time);
-            }
-            Plan::After(Condition::Timestamp(dt), ref plan) => {
-                if dt <= last_time {
-                    new_plan = Some((**plan).clone());
+            Plan::Race(ref a, ref b) => {
+                if a.0.is_satisfied(&event) {
+                    new_action = Some(a.1.clone());
+                } else if b.0.is_satisfied(&event) {
+                    new_action = Some(b.1.clone());
                 }
             }
-            _ => (),
-        }
-        if self.run_race() {
-            return true;
         }
 
-        if let Some(plan) = new_plan {
-            mem::replace(self, plan);
+        if let Some(action) = new_action {
+            mem::replace(self, Plan::Action(action));
             true
         } else {
             false

src/transaction.rs

@@ -18,10 +18,7 @@ pub struct Transaction {
 impl Transaction {
     pub fn new(from_keypair: &KeyPair, to: PublicKey, asset: i64, last_id: Hash) -> Self {
         let from = from_keypair.pubkey();
-        let plan = Plan::Action(Action::Pay(Payment {
-            asset: asset.clone(),
-            to,
-        }));
+        let plan = Plan::Action(Action::Pay(Payment { asset, to }));
         let mut tr = Transaction {
             from,
             plan,
@@ -42,20 +39,11 @@ impl Transaction {
     ) -> Self {
         let from = from_keypair.pubkey();
         let plan = Plan::Race(
-            Box::new(Plan::After(
-                Condition::Timestamp(dt),
-                Box::new(Plan::Action(Action::Pay(Payment {
-                    asset: asset.clone(),
-                    to,
-                }))),
-            )),
-            Box::new(Plan::After(
+            (Condition::Timestamp(dt), Action::Pay(Payment { asset, to })),
+            (
                 Condition::Signature(from),
-                Box::new(Plan::Action(Action::Pay(Payment {
-                    asset: asset.clone(),
-                    to: from,
-                }))),
-            )),
+                Action::Pay(Payment { asset, to: from }),
+            ),
         );
         let mut tr = Transaction {
             from,