Merge pull request #1068 from limebell/refactor/block-demand

Introduce BlockDemand in Swarm

Libplanet/Net/BlockDemand.cs

@@ -0,0 +1,27 @@
+#nullable enable
+using Libplanet.Blocks;
+
+namespace Libplanet.Net
+{
+    /// <summary>
+    /// Struct represents <see cref="Swarm{T}"/>'s block demand status.
+    /// </summary>
+    public readonly struct BlockDemand
+    {
+        /// <summary>
+        /// The <see cref="BlockHeader"/> of the block to request.
+        /// </summary>
+        public readonly BlockHeader Header;
+
+        /// <summary>
+        /// The <see cref="BoundPeer"/> to request block hash from.
+        /// </summary>
+        public readonly BoundPeer Peer;
+
+        public BlockDemand(BlockHeader header, BoundPeer peer)
+        {
+            Header = header;
+            Peer = peer;
+        }
+    }
+}

Libplanet/Net/Swarm.MessageHandlers.cs

@@ -11,7 +11,6 @@
 using Libplanet.Net.Messages;
 using Libplanet.Store;
 using Libplanet.Tx;
-using Serilog;
 using Serilog.Events;
 
 namespace Libplanet.Net
@@ -185,12 +184,12 @@ private async Task ProcessBlockHeader(
             {
                 if (IsDemandNeeded(header))
                 {
-                    Log.Debug(
+                    _logger.Debug(
                         "BlockHashDemand #{index} {blockHash} from {peer}.",
                         header.Index,
                         ByteUtil.Hex(header.Hash),
                         peer);
-                    _demandBlockHash = new BlockHashDemand(header, peer);
+                    BlockDemand = new BlockDemand(header, peer);
                 }
                 else
                 {
@@ -199,7 +198,7 @@ private async Task ProcessBlockHeader(
                         "(current: {Current}, demand: {Demand}, received: {Received});" +
                         $" {nameof(BlockHeaderMessage)} is ignored.",
                         BlockChain.Tip.Index,
-                        _demandBlockHash?.Header.Index,
+                        BlockDemand?.Header.Index,
                         header.Index);
                 }
             }

Libplanet/Net/Swarm.cs

@@ -40,8 +40,6 @@ public partial class Swarm<T> : IDisposable
 
         private CancellationTokenSource _workerCancellationTokenSource;
         private CancellationToken _cancellationToken;
-
-        private BlockHashDemand? _demandBlockHash;
         private ConcurrentDictionary<TxId, BoundPeer> _demandTxIds;
 
         static Swarm()
@@ -206,6 +204,13 @@ public IDictionary<Peer, DateTimeOffset> LastSeenTimestamps
 
         public AppProtocolVersion AppProtocolVersion => _appProtocolVersion;
 
+        /// <summary>
+        /// Information of <see cref="Swarm{T}"/>'s demand for new blocks.
+        /// It is null when the <see cref="Swarm{T}"/> does not have any block to demand.
+        /// <seealso cref="BlockDemand"/>
+        /// </summary>
+        public BlockDemand? BlockDemand { get; private set; }
+
         internal ITransport Transport { get; private set; }
 
         internal IProtocol Protocol => (Transport as NetMQTransport)?.Protocol;
@@ -361,7 +366,7 @@ public async Task StartAsync(
             _cancellationToken = CancellationTokenSource.CreateLinkedTokenSource(
                     _workerCancellationTokenSource.Token, cancellationToken
                 ).Token;
-            _demandBlockHash = null;
+            BlockDemand = null;
             _demandTxIds = new ConcurrentDictionary<TxId, BoundPeer>();
             await Transport.StartAsync(_cancellationToken);
 
@@ -1671,8 +1676,8 @@ private void BroadcastTxIds(Address? except, IEnumerable<TxId> txIds)
         private bool IsDemandNeeded(BlockHeader target)
         {
             return target.TotalDifficulty > BlockChain.Tip.TotalDifficulty &&
-                   (_demandBlockHash is null ||
-                    _demandBlockHash.Value.Header.TotalDifficulty < target.TotalDifficulty);
+                   (BlockDemand is null ||
+                    BlockDemand.Value.Header.TotalDifficulty < target.TotalDifficulty);
         }
 
         private async Task SyncPreviousBlocksAsync(
@@ -1898,15 +1903,15 @@ CancellationToken cancellationToken
         {
             while (!cancellationToken.IsCancellationRequested)
             {
-                if (_demandBlockHash is null ||
-                    _demandBlockHash.Value.Header.TotalDifficulty <= BlockChain.Tip.TotalDifficulty)
+                if (BlockDemand is null ||
+                    BlockDemand.Value.Header.TotalDifficulty <= BlockChain.Tip.TotalDifficulty)
                 {
                     await Task.Delay(1, cancellationToken);
                     continue;
                 }
 
-                BoundPeer peer = _demandBlockHash.Value.Peer;
-                var hash = new HashDigest<SHA256>(_demandBlockHash.Value.Header.Hash.ToArray());
+                BoundPeer peer = BlockDemand.Value.Peer;
+                var hash = new HashDigest<SHA256>(BlockDemand.Value.Header.Hash.ToArray());
 
                 try
                 {
@@ -1947,7 +1952,7 @@ await SyncPreviousBlocksAsync(
                 {
                     using (await _blockSyncMutex.LockAsync(cancellationToken))
                     {
-                        _demandBlockHash = null;
+                        BlockDemand = null;
                     }
                 }
             }