Refactor timers used in Nominator

Use enums to identify timers within an array of timers. Just create them
in the constructor and arm them when needed. Stop all timers on
shutdown.

source/agora/consensus/protocol/Nominator.d

@@ -60,7 +60,7 @@ import std.container : DList;
 import std.conv;
 import std.format;
 import std.path : buildPath;
-import std.range : assumeSorted;
+import std.range : assumeSorted, chain;
 import core.time;
 
 // TODO: The block should probably have a size limit rather than a maximum
@@ -110,12 +110,24 @@ public extern (C++) class Nominator : SCPDriver
     /// Last height that we finished the nomination round
     private Height heighest_ballot_height;
 
-    /// Periodic nomination timer. It runs every second and checks the clock
-    /// time to see if it's time to start nominating. We do not use the
-    /// `BlockInterval` interval directly because this makes the timer
-    /// succeptible to clock drift. Instead, the clock is checked every second.
-    /// Note that Clock network synchronization is not yet implemented.
-    private ITimer nomination_timer;
+    ///
+    protected enum TimersIdx
+    {
+        /// Periodic nomination timer. It runs every second and checks the clock
+        /// time to see if it's time to start nominating. We do not use the
+        /// `BlockInterval` interval directly because this makes the timer
+        /// succeptible to clock drift. Instead, the clock is checked every second.
+        /// Note that Clock network synchronization is not yet implemented.
+        Nomination,
+        /// Timer used for processing queued incoming SCP Envelope messages
+        Envelope,
+        /// Timer passed in from FullNode or Validator to trigger block,
+        /// signature and tx catchup
+        Catchup,
+    }
+
+    /// Timers this node has started not including the SCP slot timers
+    protected ITimer[TimersIdx.max + 1] timers;
 
     /// SCPEnvelopeStore instance
     protected SCPEnvelopeStore store;
@@ -148,15 +160,9 @@ public extern (C++) class Nominator : SCPDriver
     /// List of incoming SCPEnvelopes that need to be processed
     private DList!SCPEnvelope queued_envelopes;
 
-    /// Timer used for processing queued incoming SCP Envelope messages
-    private ITimer envelope_timer;
-
     /// Envelope process task delay
     private enum EnvTaskDelay = 10.msecs;
 
-    // Timer used to enable catchup in background as task
-    private ITimer catchup_timer;
-
     /// catchup task delay
     private enum CatchupTaskDelay = 10.msecs;
 
@@ -204,11 +210,11 @@ extern(D):
         this.ledger = ledger;
         this.enroll_man = enroll_man;
         this.store = new SCPEnvelopeStore(cacheDB);
-        // Create and stop timer immediately
-        this.envelope_timer = this.taskman.setTimer(EnvTaskDelay,
-            &this.envelopeProcessTask, Periodic.No);
-        this.envelope_timer.stop();
-        this.catchup_timer = catchup_timer;
+        // Create stopped timers
+        this.timers[TimersIdx.Envelope] = this.taskman.createTimer(&this.envelopeProcessTask);
+        this.timers[TimersIdx.Nomination] = this.taskman.createTimer(&this.checkNominate);
+        this.timers[TimersIdx.Catchup] = catchup_timer; // Created in caller
+
         // Find the node id of this validator and create an SCPObject
         Hash[] utxo_keys;
         this.enroll_man.getEnrolledUTXOs(Height(1), utxo_keys);
@@ -220,10 +226,14 @@ extern(D):
         this.acceptBlock = externalize;
     }
 
-    /// Shut down the envelope processing timer
+    /// Shut down the timers
     public void shutdown () @safe
     {
-        this.envelope_timer.stop();
+        this.timers[].chain(this.active_timers[]).each!((t)
+        {
+            if (t !is null)
+                t.stop();
+        });
     }
 
     /// Processes incoming queued envelopes
@@ -346,13 +356,11 @@ extern(D):
 
     public void startNominatingTimer () @trusted nothrow
     {
-        if (this.nomination_timer !is null)  // already running
-            return;
-
-        // For unittests we don't want to wait 1 second between checks
         log.info("Starting nominating timer..");
-        this.nomination_timer = this.taskman.setTimer(this.nomination_interval,
-            &this.checkNominate, Periodic.Yes);
+        if (this.timers[TimersIdx.Nomination] is null)
+            this.timers[TimersIdx.Nomination] = this.taskman.createTimer(&this.checkNominate);
+
+        this.timers[TimersIdx.Nomination].rearm(this.nomination_interval, false);
     }
 
     /***************************************************************************
@@ -365,10 +373,11 @@ extern(D):
 
     public void stopNominatingTimer () @safe nothrow
     {
-        if (this.nomination_timer !is null)
+        log.info("Stopping nominating timer.");
+        if (this.timers[TimersIdx.Nomination] !is null)
         {
-            this.nomination_timer.stop();
-            this.nomination_timer = null;
+            this.timers[TimersIdx.Nomination].stop();
+            this.timers[TimersIdx.Nomination] = null;
         }
     }
 
@@ -462,6 +471,10 @@ extern(D):
 
     protected void checkNominate () @safe
     {
+        scope (exit)
+        {
+            this.timers[TimersIdx.Nomination].rearm(this.nomination_interval, false);
+        }
         const slot_idx = this.ledger.height() + 1;
         const cur_time = this.clock.networkTime();
         const next_nomination = this.getExpectedBlockTime();
@@ -478,7 +491,7 @@ extern(D):
             this.log.trace(
                 "checkNominate(): Last block ({}) doesn't have majority signatures, signed={}",
                 this.ledger.height(), this.ledger.lastBlock().header.validators);
-            this.catchup_timer.rearm(CatchupTaskDelay, false);
+            this.timers[TimersIdx.Catchup].rearm(CatchupTaskDelay, false);
             return;
         }
 
@@ -577,7 +590,7 @@ extern(D):
             if (!proc)
             {
                 this.queued_envelopes.insertBack(envelope.serializeFull.deserializeFull!SCPEnvelope());
-                this.envelope_timer.rearm(EnvTaskDelay, Periodic.No);
+                this.timers[TimersIdx.Envelope].rearm(EnvTaskDelay, false);
                 continue;
             }
             auto shared_env = this.wrapEnvelope(envelope);
@@ -608,7 +621,7 @@ extern(D):
                 this.queued_envelopes.insertBack(copied);
             else
                 this.queued_envelopes.insertFront(copied);
-            this.envelope_timer.rearm(EnvTaskDelay, Periodic.No);
+            this.timers[TimersIdx.Envelope].rearm(EnvTaskDelay, false);
             this.seen_envs.put(env_hash);
         }
     }
@@ -626,7 +639,7 @@ extern(D):
     {
         // ignore messages if `startNominatingTimer` was never called or
         // if `stopNominatingTimer` was called
-        if (this.nomination_timer is null)
+        if (this.timers[TimersIdx.Nomination] is null)
             return;
 
         const Block last_block = this.ledger.lastBlock();
@@ -913,13 +926,13 @@ extern(D):
             if (fail_reason == this.ledger.InvalidConsensusDataReason.NotInPool)
             {
                 log.trace("validateValue(): This node can not yet fully validate this value: {}. Data: {}", fail_reason, data.prettify);
-                this.catchup_timer.rearm(CatchupTaskDelay, false);
+                this.timers[TimersIdx.Catchup].rearm(CatchupTaskDelay, false);
                 return ValidationLevel.kMaybeValidValue;
             }
             if (fail_reason == this.ledger.InvalidConsensusDataReason.MisMatchingCoinbase)
             {
                 log.error("validateValue(): Validation failed: {}. Will check for missing signatures", fail_reason);
-                this.catchup_timer.rearm(CatchupTaskDelay, false);
+                this.timers[TimersIdx.Catchup].rearm(CatchupTaskDelay, false);
             }
             else
             {