Do not create consumerTag string in HandleBasicDeliver when conumer exists in the dictionary

Author: Gábor Zavarkó

projects/Benchmarks/ConsumerDispatching/ConsumerDispatcher.cs

@@ -15,6 +15,7 @@ public class ConsumerDispatcherBase
         private protected IConsumerDispatcher _dispatcher;
         private protected readonly AsyncBasicConsumerFake _consumer = new AsyncBasicConsumerFake(_autoResetEvent);
         protected readonly string _consumerTag = "ConsumerTag";
+        protected static readonly byte[] _consumerTagBytes = Encoding.UTF8.GetBytes("ConsumerTag");
         protected readonly ulong _deliveryTag = 500UL;
         protected static readonly byte[] _exchange = Encoding.UTF8.GetBytes("Exchange");
         protected static readonly byte[] _routingKey = Encoding.UTF8.GetBytes("RoutingKey");
@@ -43,7 +44,7 @@ public void AsyncConsumerDispatcher()
         {
             for (int i = 0; i < Count; i++)
             {
-                _dispatcher.HandleBasicDeliver(_consumerTag, _deliveryTag, false, _exchange, _routingKey, _properties, _body, _method, _body);
+                _dispatcher.HandleBasicDeliver(_consumerTagBytes, _deliveryTag, false, _exchange, _routingKey, _properties, _body, _method, _body);
             }
             _autoResetEvent.Wait();
             _autoResetEvent.Reset();
@@ -61,7 +62,7 @@ public void ConsumerDispatcher()
         {
             for (int i = 0; i < Count; i++)
             {
-                _dispatcher.HandleBasicDeliver(_consumerTag, _deliveryTag, false, _exchange, _routingKey, _properties, _body, _method, _body);
+                _dispatcher.HandleBasicDeliver(_consumerTagBytes, _deliveryTag, false, _exchange, _routingKey, _properties, _body, _method, _body);
             }
             _autoResetEvent.Wait();
             _autoResetEvent.Reset();

projects/RabbitMQ.Client/client/framing/BasicDeliver.cs

@@ -38,15 +38,15 @@ namespace RabbitMQ.Client.Framing.Impl
 {
     internal readonly struct BasicDeliver : IAmqpMethod
     {
-        public readonly string _consumerTag;
+        public readonly ReadOnlyMemory<byte> _consumerTag;
         public readonly ulong _deliveryTag;
         public readonly bool _redelivered;
         public readonly ReadOnlyMemory<byte> _exchange;
         public readonly ReadOnlyMemory<byte> _routingKey;
 
         public BasicDeliver(ReadOnlyMemory<byte> data)
         {
-            int offset = WireFormatting.ReadShortstr(data.Span, out _consumerTag);
+            int offset = WireFormatting.ReadShortMemory(data, out _consumerTag);
             offset += WireFormatting.ReadLonglong(data.Span.Slice(offset), out _deliveryTag);
             offset += WireFormatting.ReadBits(data.Span.Slice(offset), out _redelivered);
             offset += WireFormatting.ReadShortMemory(data.Slice(offset), out _exchange);

projects/RabbitMQ.Client/client/impl/ConsumerDispatching/ConsumerDispatcherBase.cs

@@ -1,53 +1,87 @@
-using System.Collections.Generic;
+using System;
+using System.Buffers;
+using System.Collections.Generic;
 using System.Runtime.CompilerServices;
+using System.Text;
 using System.Threading.Tasks;
+using RabbitMQ.Util;
 
 namespace RabbitMQ.Client.ConsumerDispatching
 {
 #nullable enable
     internal abstract class ConsumerDispatcherBase
     {
         private static readonly FallbackConsumer fallbackConsumer = new FallbackConsumer();
-        private readonly Dictionary<string, IBasicConsumer> _consumers;
+        private readonly Dictionary<ReadOnlyMemory<byte>, (IBasicConsumer consumer, string consumerTag)> _consumers;
 
         public IBasicConsumer? DefaultConsumer { get; set; }
 
         protected ConsumerDispatcherBase()
         {
-            _consumers = new Dictionary<string, IBasicConsumer>();
+            _consumers = new Dictionary<ReadOnlyMemory<byte>, (IBasicConsumer, string)>(MemoryOfByteEqualityComparer.Instance);
         }
 
         protected void AddConsumer(IBasicConsumer consumer, string tag)
         {
             lock (_consumers)
             {
-                _consumers[tag] = consumer;
+                var tagBytes = Encoding.UTF8.GetBytes(tag);
+                _consumers[tagBytes] = (consumer, tag);
             }
         }
 
-        protected IBasicConsumer GetConsumerOrDefault(string tag)
+        protected (IBasicConsumer consumer, string consumerTag) GetConsumerOrDefault(ReadOnlyMemory<byte> tag)
         {
             lock (_consumers)
             {
-                return _consumers.TryGetValue(tag, out var consumer) ? consumer : GetDefaultOrFallbackConsumer();
+                if (_consumers.TryGetValue(tag, out var consumerPair))
+                {
+                    return consumerPair;
+                }
+
+#if !NETSTANDARD
+                var consumerTag = Encoding.UTF8.GetString(tag.Span);
+#else
+                string consumerTag;
+                unsafe
+                {
+                    fixed (byte* bytes = tag.Span)
+                    {
+                        consumerTag = Encoding.UTF8.GetString(bytes, tag.Length);
+                    }
+                }
+#endif
+
+                return (GetDefaultOrFallbackConsumer(), consumerTag);
             }
         }
 
         public IBasicConsumer GetAndRemoveConsumer(string tag)
         {
             lock (_consumers)
             {
-                return _consumers.Remove(tag, out var consumer) ? consumer : GetDefaultOrFallbackConsumer();
+                var utf8 = Encoding.UTF8;
+                var pool = ArrayPool<byte>.Shared;
+                var buf = pool.Rent(utf8.GetMaxByteCount(tag.Length));
+#if NETSTANDARD
+                int count = utf8.GetBytes(tag, 0, tag.Length, buf, 0);
+#else
+                int count = utf8.GetBytes(tag, buf);
+#endif
+                var memory = buf.AsMemory(0, count);
+                var result = _consumers.Remove(memory, out var consumerPair) ? consumerPair.consumer : GetDefaultOrFallbackConsumer();
+                pool.Return(buf);
+                return result;
             }
         }
 
         public Task ShutdownAsync(ShutdownEventArgs reason)
         {
             lock (_consumers)
             {
-                foreach (KeyValuePair<string, IBasicConsumer> pair in _consumers)
+                foreach (KeyValuePair<ReadOnlyMemory<byte>, (IBasicConsumer consumer, string consumerTag)> pair in _consumers)
                 {
-                    ShutdownConsumer(pair.Value, reason);
+                    ShutdownConsumer(pair.Value.consumer, reason);
                 }
                 _consumers.Clear();
             }

projects/RabbitMQ.Client/client/impl/ConsumerDispatching/ConsumerDispatcherChannelBase.cs

@@ -53,12 +53,13 @@ public void HandleBasicConsumeOk(IBasicConsumer consumer, string consumerTag)
             }
         }
 
-        public void HandleBasicDeliver(string consumerTag, ulong deliveryTag, bool redelivered,
+        public void HandleBasicDeliver(ReadOnlyMemory<byte> consumerTag, ulong deliveryTag, bool redelivered,
             ReadOnlyMemory<byte> exchange, ReadOnlyMemory<byte> routingKey, in ReadOnlyBasicProperties basicProperties, ReadOnlyMemory<byte> body, byte[] rentedMethodArray, byte[] rentedArray)
         {
             if (!IsShutdown)
             {
-                _writer.TryWrite(new WorkStruct(GetConsumerOrDefault(consumerTag), consumerTag, deliveryTag, redelivered, exchange, routingKey, basicProperties, body, rentedMethodArray, rentedArray));
+                var consumerPair = GetConsumerOrDefault(consumerTag);
+                _writer.TryWrite(new WorkStruct(consumerPair.consumer, consumerPair.consumerTag, deliveryTag, redelivered, exchange, routingKey, basicProperties, body, rentedMethodArray, rentedArray));
             }
         }
 

projects/RabbitMQ.Client/client/impl/ConsumerDispatching/IConsumerDispatcher.cs

@@ -45,7 +45,7 @@ internal interface IConsumerDispatcher
 
         void HandleBasicConsumeOk(IBasicConsumer consumer, string consumerTag);
 
-        void HandleBasicDeliver(string consumerTag,
+        void HandleBasicDeliver(ReadOnlyMemory<byte> consumerTag,
                             ulong deliveryTag,
                             bool redelivered,
                             ReadOnlyMemory<byte> exchange,

projects/RabbitMQ.Client/util/MemoryOfByteEqualityComparer.cs

@@ -0,0 +1,41 @@
+using System;
+using System.Collections.Generic;
+using System.Runtime.InteropServices;
+
+namespace RabbitMQ.Util;
+
+internal sealed class MemoryOfByteEqualityComparer : IEqualityComparer<ReadOnlyMemory<byte>>
+{
+    public static MemoryOfByteEqualityComparer Instance { get; } = new MemoryOfByteEqualityComparer();
+
+    public bool Equals(ReadOnlyMemory<byte> left, ReadOnlyMemory<byte> right)
+    {
+        return left.Span.SequenceEqual(right.Span);
+    }
+
+    public int GetHashCode(ReadOnlyMemory<byte> value)
+    {
+#if NETSTANDARD
+            unchecked
+            {
+                int hashCode = 0;
+                var longPart = MemoryMarshal.Cast<byte, long>(value.Span);
+                foreach (long item in longPart)
+                {
+                    hashCode = (hashCode * 397) ^ item.GetHashCode();
+                }
+
+                foreach (int item in value.Span.Slice(longPart.Length * 8))
+                {
+                    hashCode = (hashCode * 397) ^ item.GetHashCode();
+                }
+
+                return hashCode;
+            }
+#else
+        HashCode result = default;
+        result.AddBytes(value.Span);
+        return result.ToHashCode();
+#endif
+    }
+}