Async fixups (#118)

* fix: avoid potential deadlocks

* fix: use an async method when available

* fix: always use 'Async' suffix for an async method name

* fix: always use 'Async' suffix for an async method name

src/BlockExchange/Bitswap.cs

@@ -129,7 +129,9 @@ public Task StartAsync()
 
         // When a connection is established
         // (1) Send the local peer's want list to the remote
+#pragma warning disable VSTHRD100 // Avoid async void methods
         async void Swarm_ConnectionEstablished(object sender, PeerConnection connection)
+#pragma warning restore VSTHRD100 // Avoid async void methods
         {
             try
             {
@@ -206,7 +208,7 @@ public IEnumerable<Cid> PeerWants(MultiHash peer)
         ///   <see cref="Unwant"/> method will also cancel the operation.
         ///   </para>
         /// </remarks>
-        public Task<IDataBlock> Want(Cid id, MultiHash peer, CancellationToken cancel)
+        public Task<IDataBlock> WantAsync(Cid id, MultiHash peer, CancellationToken cancel)
         {
             log.Trace($"{peer} wants {id}");
 

src/BlockExchange/Bitswap1.cs

@@ -100,7 +100,7 @@ async Task GetBlockAsync(Cid cid, Peer remotePeer, CancellationToken cancel)
                 }
                 else
                 {
-                    block = await Bitswap.Want(cid, remotePeer.Id, cancel).ConfigureAwait(false);
+                    block = await Bitswap.WantAsync(cid, remotePeer.Id, cancel).ConfigureAwait(false);
                 }
 
                 // Send block to remote.

src/BlockExchange/Bitswap11.cs

@@ -109,7 +109,7 @@ async Task GetBlockAsync(Cid cid, Peer remotePeer, CancellationToken cancel)
                 }
                 else
                 {
-                    block = await Bitswap.Want(cid, remotePeer.Id, cancel).ConfigureAwait(false);
+                    block = await Bitswap.WantAsync(cid, remotePeer.Id, cancel).ConfigureAwait(false);
                 }
 
                 // Send block to remote.

src/CoreApi/BitswapApi.cs

@@ -20,7 +20,7 @@ public async Task<IDataBlock> GetAsync(Cid id, CancellationToken cancel = defaul
         {
             var bs = await ipfs.BitswapService.ConfigureAwait(false);
             var peer = await ipfs.LocalPeer.ConfigureAwait(false);
-            return await bs.Want(id, peer.Id, cancel).ConfigureAwait(false);
+            return await bs.WantAsync(id, peer.Id, cancel).ConfigureAwait(false);
         }
 
         public async Task UnwantAsync(Cid id, CancellationToken cancel = default(CancellationToken))

src/CoreApi/BlockApi.cs

@@ -127,7 +127,7 @@ public async Task<IDataBlock> GetAsync(Cid id, CancellationToken cancel = defaul
                     id: id,
                     limit: 20, // TODO: remove this
                     cancel: queryCancel.Token,
-                    action: (peer) => { var __ = ProviderFound(peer, queryCancel.Token).ConfigureAwait(false); }
+                    action: (peer) => { var __ = ProviderFoundAsync(peer, queryCancel.Token).ConfigureAwait(false); }
                 );
 
                 var got = await bitswapGet;
@@ -138,7 +138,7 @@ public async Task<IDataBlock> GetAsync(Cid id, CancellationToken cancel = defaul
             }
         }
 
-        async Task ProviderFound(Peer peer, CancellationToken cancel)
+        async Task ProviderFoundAsync(Peer peer, CancellationToken cancel)
         {
             if (cancel.IsCancellationRequested)
                 return;

src/CoreApi/DagApi.cs

@@ -15,7 +15,7 @@ namespace Ipfs.Engine.CoreApi
 {
     class DagApi : IDagApi
     {
-        static PODOptions podOptions = new PODOptions
+        static readonly PODOptions podOptions = new PODOptions
         (
             removeIsPrefix: false,
             useCamelCase: false
@@ -96,7 +96,7 @@ public DagApi(IpfsEngine ipfs)
             using (var sw = new StreamWriter(ms))
             using (var writer = new JsonTextWriter(sw))
             {
-                data.WriteTo(writer);
+                await data.WriteToAsync(writer);
                 writer.Flush();
                 ms.Position = 0;
                 var format = GetDataFormat(contentType);

src/CoreApi/DnsApi.cs

@@ -29,8 +29,8 @@ public async Task<string> ResolveAsync(string name, bool recursive = false, Canc
                 {
                     var attempts = new Task<string>[]
                     {
-                        Find(name, cts.Token),
-                        Find("_dnslink." + name, cts.Token)
+                        FindAsync(name, cts.Token),
+                        FindAsync("_dnslink." + name, cts.Token)
                     };
                     link = await TaskHelper.WhenAnyResult(attempts, cancel).ConfigureAwait(false);
                     cts.Cancel();
@@ -52,7 +52,7 @@ public async Task<string> ResolveAsync(string name, bool recursive = false, Canc
             throw new NotSupportedException($"Cannot resolve '{link}'.");
         }
 
-        async Task<string> Find(string name, CancellationToken cancel)
+        async Task<string> FindAsync(string name, CancellationToken cancel)
         {
             var response = await ipfs.Options.Dns.QueryAsync(name, DnsType.TXT, cancel).ConfigureAwait(false);
             var link = response.Answers

src/CoreApi/FileSystemApi.cs

@@ -57,7 +57,7 @@ public FileSystemApi(IpfsEngine ipfs)
             if (options.Trickle) throw new NotImplementedException("Trickle");
 
             var blockService = GetBlockService(options);
-            var keyChain = await ipfs.KeyChain(cancel).ConfigureAwait(false);
+            var keyChain = await ipfs.KeyChainAsync(cancel).ConfigureAwait(false);
 
             var chunker = new SizeChunker();
             var nodes = await chunker.ChunkAsync(stream, name, options, blockService, keyChain, cancel).ConfigureAwait(false);
@@ -255,8 +255,8 @@ public async Task<string> ReadAllTextAsync(string path, CancellationToken cancel
         public async Task<Stream> ReadFileAsync(string path, CancellationToken cancel = default(CancellationToken))
         {
             var cid = await ipfs.ResolveIpfsPathToCidAsync(path, cancel).ConfigureAwait(false);
-            var keyChain = await ipfs.KeyChain(cancel).ConfigureAwait(false);
-            return await FileSystem.CreateReadStream(cid, ipfs.Block, keyChain, cancel).ConfigureAwait(false);
+            var keyChain = await ipfs.KeyChainAsync(cancel).ConfigureAwait(false);
+            return await FileSystem.CreateReadStreamAsync(cid, ipfs.Block, keyChain, cancel).ConfigureAwait(false);
         }
 
         public async Task<Stream> ReadFileAsync(string path, long offset, long count = 0, CancellationToken cancel = default(CancellationToken))
@@ -317,7 +317,7 @@ async Task AddTarNodeAsync(Cid cid, string name, TarOutputStream tar, Cancellati
                 header.TypeFlag = TarHeader.LF_NORMAL;
                 header.Size = content.Length;
                 tar.PutNextEntry(entry);
-                content.CopyTo(tar);
+                await content.CopyToAsync(tar);
                 tar.CloseEntry();
             }
 

src/CoreApi/KeyApi.cs

@@ -19,37 +19,37 @@ public KeyApi(IpfsEngine ipfs)
 
         public async Task<IKey> CreateAsync(string name, string keyType, int size, CancellationToken cancel = default(CancellationToken))
         {
-            var keyChain = await ipfs.KeyChain(cancel).ConfigureAwait(false);
+            var keyChain = await ipfs.KeyChainAsync(cancel).ConfigureAwait(false);
             return await keyChain.CreateAsync(name, keyType, size, cancel).ConfigureAwait(false);
         }
 
         public async Task<string> ExportAsync(string name, char[] password, CancellationToken cancel = default(CancellationToken))
         {
-            var keyChain = await ipfs.KeyChain(cancel).ConfigureAwait(false);
+            var keyChain = await ipfs.KeyChainAsync(cancel).ConfigureAwait(false);
             return await keyChain.ExportAsync(name, password, cancel).ConfigureAwait(false);
         }
 
         public async Task<IKey> ImportAsync(string name, string pem, char[] password = null, CancellationToken cancel = default(CancellationToken))
         {
-            var keyChain = await ipfs.KeyChain(cancel).ConfigureAwait(false);
+            var keyChain = await ipfs.KeyChainAsync(cancel).ConfigureAwait(false);
             return await keyChain.ImportAsync(name, pem, password, cancel).ConfigureAwait(false);
         }
 
         public async Task<IEnumerable<IKey>> ListAsync(CancellationToken cancel = default(CancellationToken))
         {
-            var keyChain = await ipfs.KeyChain(cancel).ConfigureAwait(false);
+            var keyChain = await ipfs.KeyChainAsync(cancel).ConfigureAwait(false);
             return await keyChain.ListAsync(cancel).ConfigureAwait(false);
         }
 
         public async Task<IKey> RemoveAsync(string name, CancellationToken cancel = default(CancellationToken))
         {
-            var keyChain = await ipfs.KeyChain(cancel).ConfigureAwait(false);
+            var keyChain = await ipfs.KeyChainAsync(cancel).ConfigureAwait(false);
             return await keyChain.RemoveAsync(name, cancel).ConfigureAwait(false);
         }
 
         public async Task<IKey> RenameAsync(string oldName, string newName, CancellationToken cancel = default(CancellationToken))
         {
-            var keyChain = await ipfs.KeyChain(cancel).ConfigureAwait(false);
+            var keyChain = await ipfs.KeyChainAsync(cancel).ConfigureAwait(false);
             return await keyChain.RenameAsync(oldName, newName, cancel).ConfigureAwait(false);
         }
     }

src/Cryptography/Cms.cs

@@ -38,7 +38,7 @@ public partial class KeyChain
         ///   is used to digitally sign, digest, authenticate, and/or encrypt
         ///   arbitrary message content.
         /// </remarks>
-        public async Task<byte[]> CreateProtectedData(
+        public async Task<byte[]> CreateProtectedDataAsync(
             string keyName, 
             byte[] plainText, 
             CancellationToken cancel = default(CancellationToken))
@@ -108,7 +108,7 @@ public partial class KeyChain
         ///   is used to digitally sign, digest, authenticate, and/or encrypt
         ///   arbitrary message content.
         /// </remarks>
-        public async Task<byte[]> ReadProtectedData(
+        public async Task<byte[]> ReadProtectedDataAsync(
             byte[] cipherText,
             CancellationToken cancel = default(CancellationToken))
         {

src/Cryptography/KeyChain.cs

@@ -365,7 +365,7 @@ async Task<IKey> AddPrivateKeyAsync(string name, AsymmetricCipherKeyPair keyPair
                 };
                 var pw = new PemWriter(sw);
                 pw.WriteObject(pkcs8);
-                pw.Writer.Flush();
+                await pw.Writer.FlushAsync();
                 pem = sw.ToString();
             }
 

src/IpfsEngine.cs

@@ -121,7 +121,7 @@ void Init()
             LocalPeer = new AsyncLazy<Peer>(async () =>
             {
                 log.Debug("Building local peer");
-                var keyChain = await KeyChain().ConfigureAwait(false);
+                var keyChain = await KeyChainAsync().ConfigureAwait(false);
                 log.Debug("Getting key info about self");
                 var self = await keyChain.FindKeyByNameAsync("self").ConfigureAwait(false);
                 var localPeer = new Peer
@@ -151,7 +151,7 @@ void Init()
                     }
                 }
                 var peer = await LocalPeer.ConfigureAwait(false);
-                var keyChain = await KeyChain().ConfigureAwait(false);
+                var keyChain = await KeyChainAsync().ConfigureAwait(false);
                 var self = await keyChain.GetPrivateKeyAsync("self").ConfigureAwait(false);
                 var swarm = new Swarm
                 {
@@ -271,8 +271,9 @@ void Init()
         ///   A task that represents the asynchronous operation. The task's result is
         ///   the <see cref="KeyChain"/>.
         /// </returns>
-        public async Task<KeyChain> KeyChain(CancellationToken cancel = default(CancellationToken))
+        public async Task<KeyChain> KeyChainAsync(CancellationToken cancel = default(CancellationToken))
         {
+            // TODO: this should be a LazyAsync property.
             if (keyChain == null)
             {
                 lock (this)
@@ -597,6 +598,7 @@ public void Stop()
         /// </summary>
         public AsyncLazy<PeerTalk.Routing.Dht1> DhtService { get; private set; }
 
+#pragma warning disable VSTHRD100 // Avoid async void methods
         /// <summary>
         ///   Fired when a peer is discovered.
         /// </summary>
@@ -606,6 +608,7 @@ public void Stop()
         ///   Registers the peer with the <see cref="SwarmService"/>.
         /// </remarks>
         async void OnPeerDiscovered(object sender, Peer peer)
+#pragma warning restore VSTHRD100 // Avoid async void methods
         {
             try
             {

src/IpfsEngine.csproj

@@ -62,6 +62,7 @@
 
   <ItemGroup>
     <PackageReference Include="Microsoft.SourceLink.GitHub" Version="1.0.0-beta2-19270-01" PrivateAssets="All" />
+    <PackageReference Include="Microsoft.VisualStudio.Threading.Analyzers" Version="16.0.102" PrivateAssets="All" />
   </ItemGroup>
 
   <ItemGroup Condition="'$(TargetFramework)' == 'netstandard14'">

src/RandomWalk.cs

@@ -113,7 +113,7 @@ void RunQuery()
             using (var timeout = new CancellationTokenSource(QueryTime))
             using (var cts = CancellationTokenSource.CreateLinkedTokenSource(timeout.Token, cancel.Token))
             {
-                var _ = Dht.FindPeerAsync(id, cts.Token).Result;
+                var _ = Dht.FindPeerAsync(id, cts.Token).ConfigureAwait(false).GetAwaiter().GetResult();
             }
         }
 

src/UnixFileSystem/ChunkedStream.cs

@@ -102,7 +102,7 @@ public override void Write(byte[] buffer, int offset, int count)
         /// <inheritdoc />
         public override int Read(byte[] buffer, int offset, int count)
         {
-            return ReadAsync(buffer, offset, count).GetAwaiter().GetResult();
+            return ReadAsync(buffer, offset, count).ConfigureAwait(false).GetAwaiter().GetResult();
         }
 
         /// <inheritdoc />
@@ -129,12 +129,12 @@ async Task<ArraySegment<byte>> GetBlockAsync (long position, CancellationToken c
             var need = blocks.Last(b => b.Position <= position);
             if (need != currentBlock)
             {
-                var stream = await FileSystem.CreateReadStream(need.Id, BlockService, KeyChain, cancel).ConfigureAwait(false);
+                var stream = await FileSystem.CreateReadStreamAsync(need.Id, BlockService, KeyChain, cancel).ConfigureAwait(false);
                 currentBlock = need;
                 currentData = new byte[stream.Length];
                 for (int i = 0, n; i < stream.Length; i += n)
                 {
-                    n = stream.Read(currentData, i, (int) stream.Length - i);
+                    n = await stream.ReadAsync(currentData, i, (int) stream.Length - i);
                 }
             }
             int offset = (int)(position - currentBlock.Position);

src/UnixFileSystem/FileSystem.cs

@@ -41,7 +41,7 @@ public static class FileSystem
         ///  The id's <see cref="Cid.ContentType"/> is used to determine how to read
         ///  the conent.
         /// </remarks>
-        public static Task<Stream> CreateReadStream(
+        public static Task<Stream> CreateReadStreamAsync(
             Cid id,
             IBlockApi blockService,
             KeyChain keyChain,
@@ -104,7 +104,7 @@ public static class FileSystem
             CancellationToken cancel)
         {
             var block = await blockService.GetAsync(id, cancel).ConfigureAwait(false);
-            var plain = await keyChain.ReadProtectedData(block.DataBytes, cancel).ConfigureAwait(false);
+            var plain = await keyChain.ReadProtectedDataAsync(block.DataBytes, cancel).ConfigureAwait(false);
             return new MemoryStream(plain, false);
         }
     }

src/UnixFileSystem/SizeChunker.cs

@@ -92,7 +92,7 @@ public class SizeChunker
                     // TODO: Inefficent to copy chunk, use ArraySegment in DataMessage.Data
                     var plain = new byte[length];
                     Array.Copy(chunk, plain, length);
-                    var cipher = await keyChain.CreateProtectedData(options.ProtectionKey, plain, cancel).ConfigureAwait(false);
+                    var cipher = await keyChain.CreateProtectedDataAsync(options.ProtectionKey, plain, cancel).ConfigureAwait(false);
                     var cid = await blockService.PutAsync(
                         data: cipher,
                         contentType: "cms",

test/BlockExchange/BitswapTest .cs

@@ -26,7 +26,7 @@ public void WantList()
 
             var cid = new DagNode(Encoding.UTF8.GetBytes("BitswapTest unknown block")).Id;
             var cancel = new CancellationTokenSource();
-            var task = bitswap.Want(cid, self.Id, cancel.Token);
+            var task = bitswap.WantAsync(cid, self.Id, cancel.Token);
             CollectionAssert.Contains(bitswap.PeerWants(self.Id).ToArray(), cid);
 
             bitswap.Unwant(cid);
@@ -39,7 +39,7 @@ public void Want_Cancel()
             var bitswap = new Bitswap { Swarm = new Swarm { LocalPeer = self } };
             var cid = new DagNode(Encoding.UTF8.GetBytes("BitswapTest unknown block")).Id;
             var cancel = new CancellationTokenSource();
-            var task = bitswap.Want(cid, self.Id, cancel.Token);
+            var task = bitswap.WantAsync(cid, self.Id, cancel.Token);
             CollectionAssert.Contains(bitswap.PeerWants(self.Id).ToArray(), cid);
 
             cancel.Cancel();
@@ -62,10 +62,10 @@ public void Block_Needed()
             };
             try
             {
-                bitswap.Want(cid1, self.Id, cancel.Token);
-                bitswap.Want(cid1, self.Id, cancel.Token);
-                bitswap.Want(cid2, self.Id, cancel.Token);
-                bitswap.Want(cid2, self.Id, cancel.Token);
+                bitswap.WantAsync(cid1, self.Id, cancel.Token);
+                bitswap.WantAsync(cid1, self.Id, cancel.Token);
+                bitswap.WantAsync(cid2, self.Id, cancel.Token);
+                bitswap.WantAsync(cid2, self.Id, cancel.Token);
                 Assert.AreEqual(2, callCount);
             }
             finally
@@ -80,7 +80,7 @@ public void Want_Unwant()
             var bitswap = new Bitswap { Swarm = new Swarm { LocalPeer = self } };
             var cid = new DagNode(Encoding.UTF8.GetBytes("BitswapTest unknown block")).Id;
             var cancel = new CancellationTokenSource();
-            var task = bitswap.Want(cid, self.Id, cancel.Token);
+            var task = bitswap.WantAsync(cid, self.Id, cancel.Token);
             CollectionAssert.Contains(bitswap.PeerWants(self.Id).ToArray(), cid);
 
             bitswap.Unwant(cid);
@@ -97,7 +97,7 @@ public void Found()
             var a = new DagNode(Encoding.UTF8.GetBytes("BitswapTest found block a"));
             var b = new DagNode(Encoding.UTF8.GetBytes("BitswapTest found block b"));
             var cancel = new CancellationTokenSource();
-            var task = bitswap.Want(a.Id, self.Id, cancel.Token);
+            var task = bitswap.WantAsync(a.Id, self.Id, cancel.Token);
             Assert.IsFalse(task.IsCompleted);
             CollectionAssert.Contains(bitswap.PeerWants(self.Id).ToArray(), a.Id);
 
@@ -120,8 +120,8 @@ public void Found_Count()
             Assert.AreEqual(0, bitswap.Found(a));
 
             var cancel = new CancellationTokenSource();
-            var task1 = bitswap.Want(a.Id, self.Id, cancel.Token);
-            var task2 = bitswap.Want(a.Id, self.Id, cancel.Token);
+            var task1 = bitswap.WantAsync(a.Id, self.Id, cancel.Token);
+            var task2 = bitswap.WantAsync(a.Id, self.Id, cancel.Token);
             Assert.AreEqual(2, bitswap.Found(a));
 
             Assert.IsTrue(task1.IsCompleted);