Nuid

.gitignore

@@ -251,3 +251,6 @@ paket-files/
 # JetBrains Rider
 .idea/
 *.sln.iml
+
+# Benchmark artifacts
+**/BenchmarkDotNet.Artifacts/

src/Benchmarks/MicroBenchmarks/Directory.Build.props

@@ -0,0 +1,7 @@
+<Project>
+  <PropertyGroup>
+    <!-- We need to override these, otherwise benchmarks won't work :/ -->
+    <TargetFrameworks></TargetFrameworks>
+    <TargetFramework></TargetFramework>
+  </PropertyGroup>
+</Project>

src/Benchmarks/MicroBenchmarks/MicroBenchmarks.csproj

@@ -0,0 +1,25 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <OutputType>Exe</OutputType>
+    <TargetFramework Condition="$(OS) != 'Windows_NT'">netcoreapp3.1</TargetFramework>
+    <TargetFrameworks Condition="$(OS) == 'Windows_NT'">netcoreapp3.1;net462</TargetFrameworks>
+    <PlatformTarget>AnyCPU</PlatformTarget>
+    <DebugType>pdbonly</DebugType>
+    <DebugSymbols>true</DebugSymbols>
+  </PropertyGroup>
+
+  <PropertyGroup Condition="$(Configuration) == 'Release'">
+    <SignAssembly>true</SignAssembly>
+    <AssemblyOriginatorKeyFile>..\..\NATS.Client.snk</AssemblyOriginatorKeyFile>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <PackageReference Include="BenchmarkDotNet" Version="0.12.0" />
+  </ItemGroup>
+
+  <ItemGroup>
+    <ProjectReference Include="..\..\NATS.Client\NATS.Client.csproj" />
+  </ItemGroup>
+
+</Project>

src/Benchmarks/MicroBenchmarks/NuidBenchmark.cs

@@ -0,0 +1,34 @@
+using BenchmarkDotNet.Attributes;
+using BenchmarkDotNet.Jobs;
+using BenchmarkDotNet.Order;
+using NATS.Client;
+using NATS.Client.Internals;
+
+namespace MicroBenchmarks
+{
+    [DisassemblyDiagnoser(printAsm: true, printSource: true)]
+    [Orderer(SummaryOrderPolicy.FastestToSlowest)]
+    [MemoryDiagnoser]
+    [MarkdownExporterAttribute.GitHub]
+    [SimpleJob(RuntimeMoniker.Net462)]
+    [SimpleJob(RuntimeMoniker.NetCoreApp31)]
+    public class NuidBenchmark
+    {
+#pragma warning disable CS0618
+        private readonly NUID _nuid = NUID.Instance;
+#pragma warning restore CS0618
+        private readonly Nuid _newNuid = new Nuid(null, 0, 1);
+
+        public NuidBenchmark()
+        {
+            _nuid.Seq = 0;
+        }
+
+        [BenchmarkCategory("NextNuid")]
+        [Benchmark(Baseline = true)]
+        public string NUIDNext() => _nuid.Next;
+
+        [BenchmarkCategory("NextNuid"), Benchmark]
+        public string NextNuid() => _newNuid.GetNext();
+    }
+}

src/Benchmarks/MicroBenchmarks/Program.cs

@@ -0,0 +1,12 @@
+using BenchmarkDotNet.Running;
+
+namespace MicroBenchmarks
+{
+    public class Program
+    {
+        public static void Main(string[] args)
+        {
+            var summary = BenchmarkRunner.Run<NuidBenchmark>();
+        }
+    }
+}

src/NATS.Client/Conn.cs

@@ -102,7 +102,7 @@ public class Connection : IConnection, IDisposable
         // .NET 4.0.
         private readonly object mu = new Object();
 
-        private Random r = null;
+        private readonly Nuid _nuid = new Nuid();
 
         Options opts = new Options();
 
@@ -3191,23 +3191,8 @@ public Task<Msg> RequestAsync(string subject, byte[] data, int offset, int count
         /// <returns>A unique inbox string.</returns>
         public string NewInbox()
         {
-            var prefix = opts.CustomInboxPrefix ?? IC.inboxPrefix;
-
-            if (!opts.UseOldRequestStyle)
-            {
-                return prefix + Guid.NewGuid().ToString("N");
-            }
-            else
-            {
-                if (r == null)
-                    r = new Random(Guid.NewGuid().GetHashCode());
-
-                byte[] buf = new byte[13];
-
-                r.NextBytes(buf);
-
-                return prefix + BitConverter.ToString(buf).Replace("-","");
-            }
+            var prefix = opts.customInboxPrefix ?? IC.inboxPrefix;
+            return prefix + _nuid.GetNext();
         }
 
         internal void sendSubscriptionMessage(AsyncSubscription s)

src/NATS.Client/Internals/Nuid.cs

@@ -0,0 +1,159 @@
+using System;
+using System.Security.Cryptography;
+using System.Threading;
+
+namespace NATS.Client.Internals
+{
+    internal sealed class Nuid
+    {
+        private const uint PREFIX_LENGTH = 12;
+        private const uint SEQUENTIAL_LENGTH = 10;
+        private const uint NUID_LENGTH = PREFIX_LENGTH + SEQUENTIAL_LENGTH;
+        private const int MIN_INCREMENT = 33;
+        private const int MAX_INCREMENT = 333;
+        private const long MAX_SEQUENTIAL = 0x1000_0000_0000_0000; //64^10
+        private const int BASE = 64;
+
+        private static readonly byte[] _digits = new byte[BASE]{
+            (byte)'A', (byte)'B', (byte)'C', (byte)'D', (byte)'E', (byte)'F', (byte)'G', (byte)'H', 
+            (byte)'I', (byte)'J', (byte)'K', (byte)'L', (byte)'M', (byte)'N', (byte)'O', (byte)'P',
+            (byte)'Q', (byte)'R', (byte)'S', (byte)'T', (byte)'U', (byte)'V', (byte)'W', (byte)'X',
+            (byte)'Y', (byte)'Z', (byte)'a', (byte)'b', (byte)'c', (byte)'d', (byte)'e', (byte)'f',
+            (byte)'g', (byte)'h', (byte)'i', (byte)'j', (byte)'k', (byte)'l', (byte)'m', (byte)'n',
+            (byte)'o', (byte)'p', (byte)'q', (byte)'r', (byte)'s', (byte)'t', (byte)'u', (byte)'v',
+            (byte)'w', (byte)'x', (byte)'y', (byte)'z', (byte)'0', (byte)'1', (byte)'2', (byte)'3', 
+            (byte)'4', (byte)'5', (byte)'6', (byte)'7', (byte)'8', (byte)'9', (byte)'+', (byte)'/',
+        };
+
+        private readonly object _nuidLock = new object();
+
+        private readonly Random _rng;
+        private readonly RandomNumberGenerator _cryptoRng;
+
+        private byte[] _prefix = new byte[PREFIX_LENGTH];
+        private int _increment;
+        private long _sequential;
+
+        /// <summary>
+        /// Initializes a new instance of <see cref="Nuid"/>.
+        /// </summary>
+        /// <remarks>
+        /// This constructor is intended to be used from unit tests and
+        /// benchmarks only. For production use use <see cref="Nuid()"/> instead.
+        /// </remarks>
+        /// <param name="rng">A cryptographically strong random number generator.</param>
+        /// <param name="sequential">The initial sequential.</param>
+        /// <param name="increment">The initial increment.</param>
+        internal Nuid(RandomNumberGenerator rng = null, long? sequential = null, int? increment = null)
+        {
+            if (rng is null)
+                _cryptoRng = RandomNumberGenerator.Create();
+            else
+                _cryptoRng = rng;
+
+            // Instantiating System.Random multiple times in quick succession without a
+            // proper seed may result in instances that yield identical sequences on .NET FX.
+            // See https://docs.microsoft.com/en-us/dotnet/api/system.random?view=netframework-4.8#instantiating-the-random-number-generator
+            // and https://docs.microsoft.com/en-us/dotnet/api/system.random?view=netframework-4.8#avoiding-multiple-instantiations
+            var seedBytes = new byte[4];
+            _cryptoRng.GetBytes(seedBytes);
+            _rng = new Random(BitConverter.ToInt32(seedBytes, 0));
+
+            if (sequential is null)
+                _sequential = GetSequential();
+            else
+                _sequential = sequential.Value;
+
+            if (increment is null)
+                _increment = GetIncrement();
+            else
+                _increment = increment.Value;
+
+            SetPrefix();
+        }
+
+        /// <summary>
+        /// Initializes a new instance of <see cref="Nuid"/>.
+        /// </summary>
+        internal Nuid() : this(null) {}
+
+        /// <summary>
+        /// Returns a random Nuid string.
+        /// </summary>
+        /// <remarks>
+        /// A Nuid is a 132 bit pseudo-random integer encoded as a base64 string
+        /// </remarks>
+        /// <returns>The Nuid</returns>
+        internal string GetNext()
+        {
+            var nuidBuffer = new char[NUID_LENGTH];
+
+            Monitor.Enter(_nuidLock);
+            long sequential = _sequential += _increment;
+            if (_sequential >= MAX_SEQUENTIAL)
+            {
+                SetPrefix();
+                sequential = _sequential = GetSequential();
+                _increment = GetIncrement();
+            }
+
+            // For small arrays this is way faster than Array.Copy and still faster than Buffer.BlockCopy
+            for (var i = 0; i < PREFIX_LENGTH; i++)
+            {
+                nuidBuffer[i] = (char)_prefix[i];
+            }
+            Monitor.Exit(_nuidLock);
+
+            for (var i = PREFIX_LENGTH; i < NUID_LENGTH; i++)
+            {
+                // We operate on unsigned integers and BASE is a power of two
+                // therefore we can optimize sequential % BASE to sequential & (BASE - 1)
+                nuidBuffer[i] = (char)_digits[(int)sequential & (BASE - 1)];
+                // BASE is 64 = 2^6 and sequential >= 0
+                // therefore we can optimize sequential / BASE to sequential >> 6
+                sequential >>= 6;
+            }
+
+            return new string(nuidBuffer);
+        }
+
+        private int GetIncrement()
+        {
+            return _rng.Next(MIN_INCREMENT, MAX_INCREMENT);
+        }
+
+        private long GetSequential()
+        {
+            var randomBytes = new byte[8];
+
+            _rng.NextBytes(randomBytes);
+
+            var sequential = BitConverter.ToUInt64(randomBytes, 0);
+
+            // NOTE: Originally we used the following algorithm to create a random long:
+            //       https://stackoverflow.com/a/13095144
+            //       Here, the uRange is const though, because it is always MAX_SEQUENTIAL - 0,
+            //       so the condition can be reduced to:
+            //       sequential > ulong.MaxValue - ((ulong.MaxValue % MAX_SEQUENTIAL) + 1) % MAX_SEQUENTIAL
+            //       The right hand side of the comparision happens to be const too now and can be folded to:
+            //       18446744073709551615 which happens to be equal to ulong.MaxValue, hence the condition will
+            //       never be true and we can omit the do-while loop entirely.
+
+            return (long)(sequential % MAX_SEQUENTIAL);
+        }
+
+        private void SetPrefix()
+        {
+            var randomBytes = new byte[PREFIX_LENGTH];
+
+            _cryptoRng.GetBytes(randomBytes);
+
+            for(var i = 0; i < randomBytes.Length; i++)
+            {
+                // We operate on unsigned integers and BASE is a power of two
+                // therefore we can optimize randomBytes[i] % BASE to randomBytes[i] & (BASE - 1)
+                _prefix[i] = _digits[randomBytes[i] & (BASE - 1)];
+            }
+        }
+    }
+}

src/NATS.Client/NATS.Client.csproj

@@ -12,6 +12,8 @@
     <PackageReleaseNotes>https://github.com/nats-io/nats.net/releases</PackageReleaseNotes>
     <PackageLicenseExpression>Apache-2.0</PackageLicenseExpression>
     <PackageTags>CNCF NATS Messaging Cloud Publish Subscribe PubSub</PackageTags>
+    <DebugType>pdbonly</DebugType>
+    <DebugSymbols>true</DebugSymbols>
   </PropertyGroup>
 
   <PropertyGroup Condition="$(Configuration) == 'Release'">
@@ -20,7 +22,7 @@
     <SignAssembly>true</SignAssembly>
     <AssemblyOriginatorKeyFile>..\NATS.Client.snk</AssemblyOriginatorKeyFile>
   </PropertyGroup>
-  
+
   <ItemGroup>
     <None Include="package-icon.png">
       <Pack>True</Pack>

src/NATS.Client/NUID.cs

@@ -22,6 +22,7 @@ namespace NATS.Client
     /// that is started at a pseudo random number and increments with a pseudo-random increment.
     /// Total is 22 bytes of base 36 ascii text.
     /// </summary>
+    [Obsolete("NATS.Client.NUID is deprecated and will be removed in a future version")]
     public class NUID
     {
         private static char[] digits = 

src/NATS.Client/Properties/AssemblyInfo.cs

@@ -0,0 +1,13 @@
+using System.Runtime.CompilerServices;
+
+// Since NATS.Client is signed, friends must be signed too.
+// We use the same SNK for simplicity.
+// https://docs.microsoft.com/en-us/dotnet/standard/assembly/create-signed-friend
+#if DEBUG
+[assembly: InternalsVisibleTo("UnitTests")]
+[assembly: InternalsVisibleTo("MicroBenchmarks")]
+
+#else
+[assembly: InternalsVisibleTo("UnitTests, PublicKey=0024000004800000940000000602000000240000525341310004000001000100db7da1f2f89089327b47d26d69666fad20861f24e9acdb13965fb6c64dfee8da589b495df37a75e934ddbacb0752a42c40f3dbc79614eec9bb2a0b6741f9e2ad2876f95e74d54c23eef0063eb4efb1e7d824ee8a695b647c113c92834f04a3a83fb60f435814ddf5c4e5f66a168139c4c1b1a50a3e60c164d180e265b1f000cd")]
+[assembly: InternalsVisibleTo("MicroBenchmarks, PublicKey=0024000004800000940000000602000000240000525341310004000001000100db7da1f2f89089327b47d26d69666fad20861f24e9acdb13965fb6c64dfee8da589b495df37a75e934ddbacb0752a42c40f3dbc79614eec9bb2a0b6741f9e2ad2876f95e74d54c23eef0063eb4efb1e7d824ee8a695b647c113c92834f04a3a83fb60f435814ddf5c4e5f66a168139c4c1b1a50a3e60c164d180e265b1f000cd")]
+#endif

src/NATS.sln

@@ -28,12 +28,16 @@ Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "Replier", "Samples\Replier\
 EndProject
 Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "QueueGroup", "Samples\QueueGroup\QueueGroup.csproj", "{2F052465-A58D-4670-8600-24CCB2F220A5}"
 EndProject
-Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "Benchmark", "Samples\Benchmark\Benchmark.csproj", "{8BC71128-1FC5-4126-9582-41223E96C2CA}"
-EndProject
 Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "RxSample", "Samples\RxSample\RxSample.csproj", "{C21CBF59-9884-436C-8A24-0248F8598979}"
 EndProject
 Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "WinFormsSample", "Samples\WinFormsSample\WinFormsSample.csproj", "{10ED0146-1701-4BC9-9E26-824B22D18CB8}"
 EndProject
+Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "Benchmark", "Benchmarks\Benchmark\Benchmark.csproj", "{8BC71128-1FC5-4126-9582-41223E96C2CA}"
+EndProject
+Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "MicroBenchmarks", "Benchmarks\MicroBenchmarks\MicroBenchmarks.csproj", "{8D181EED-3FF7-4CC0-9C85-331EF20B7688}"
+EndProject
+Project("{2150E333-8FDC-42A3-9474-1A3956D46DE8}") = "Benchmarks", "Benchmarks", "{A4CB6D96-6357-40DC-B198-50568A7E45C7}"
+EndProject
 Global
 	GlobalSection(SolutionConfigurationPlatforms) = preSolution
 		Debug|Any CPU = Debug|Any CPU
@@ -84,6 +88,10 @@ Global
 		{10ED0146-1701-4BC9-9E26-824B22D18CB8}.Debug|Any CPU.Build.0 = Debug|Any CPU
 		{10ED0146-1701-4BC9-9E26-824B22D18CB8}.Release|Any CPU.ActiveCfg = Release|Any CPU
 		{10ED0146-1701-4BC9-9E26-824B22D18CB8}.Release|Any CPU.Build.0 = Release|Any CPU
+		{8D181EED-3FF7-4CC0-9C85-331EF20B7688}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{8D181EED-3FF7-4CC0-9C85-331EF20B7688}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{8D181EED-3FF7-4CC0-9C85-331EF20B7688}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{8D181EED-3FF7-4CC0-9C85-331EF20B7688}.Release|Any CPU.Build.0 = Release|Any CPU
 	EndGlobalSection
 	GlobalSection(SolutionProperties) = preSolution
 		HideSolutionNode = FALSE
@@ -96,9 +104,10 @@ Global
 		{725F4B11-9275-4966-AD46-383021EEC152} = {776C2E80-958B-4C0D-BCC4-67D39DB4570B}
 		{B5C69B45-658C-431D-9D0D-C9D2D098248A} = {776C2E80-958B-4C0D-BCC4-67D39DB4570B}
 		{2F052465-A58D-4670-8600-24CCB2F220A5} = {776C2E80-958B-4C0D-BCC4-67D39DB4570B}
-		{8BC71128-1FC5-4126-9582-41223E96C2CA} = {776C2E80-958B-4C0D-BCC4-67D39DB4570B}
+		{8BC71128-1FC5-4126-9582-41223E96C2CA} = {A4CB6D96-6357-40DC-B198-50568A7E45C7}
 		{C21CBF59-9884-436C-8A24-0248F8598979} = {776C2E80-958B-4C0D-BCC4-67D39DB4570B}
 		{10ED0146-1701-4BC9-9E26-824B22D18CB8} = {776C2E80-958B-4C0D-BCC4-67D39DB4570B}
+		{8D181EED-3FF7-4CC0-9C85-331EF20B7688} = {A4CB6D96-6357-40DC-B198-50568A7E45C7}
 	EndGlobalSection
 	GlobalSection(ExtensibilityGlobals) = postSolution
 		SolutionGuid = {0972F03C-E4DF-483A-B767-9216F4434F11}