From 752022ee894cf53ad0b537d51e57d3e111b88fa8 Mon Sep 17 00:00:00 2001
From: Andrew Arnott <andrewarnott@live.com>
Date: Sat, 17 Apr 2021 11:36:54 -0600
Subject: [PATCH] Add support for `IReadOnlySet<T>`

Closes #1217
---
 .../Formatters/CollectionFormatter.cs         | 22 +++++++++++++++++++
 .../Resolvers/DynamicGenericResolver.cs       |  3 +++
 .../net5.0/PublicAPI.Unshipped.txt            |  2 ++
 3 files changed, 27 insertions(+)

diff --git a/src/MessagePack.UnityClient/Assets/Scripts/MessagePack/Formatters/CollectionFormatter.cs b/src/MessagePack.UnityClient/Assets/Scripts/MessagePack/Formatters/CollectionFormatter.cs
index f6bf5d23f..2255cd707 100644
--- a/src/MessagePack.UnityClient/Assets/Scripts/MessagePack/Formatters/CollectionFormatter.cs
+++ b/src/MessagePack.UnityClient/Assets/Scripts/MessagePack/Formatters/CollectionFormatter.cs
@@ -1271,6 +1271,28 @@ protected override HashSet<T> Create(int count, MessagePackSerializerOptions opt
         }
     }
 
+#if NET5_0_OR_GREATER
+
+    public sealed class InterfaceReadOnlySetFormatter<T> : CollectionFormatterBase<T, HashSet<T>, IReadOnlySet<T>>
+    {
+        protected override void Add(HashSet<T> collection, int index, T value, MessagePackSerializerOptions options)
+        {
+            collection.Add(value);
+        }
+
+        protected override IReadOnlySet<T> Complete(HashSet<T> intermediateCollection)
+        {
+            return intermediateCollection;
+        }
+
+        protected override HashSet<T> Create(int count, MessagePackSerializerOptions options)
+        {
+            return new HashSet<T>(options.Security.GetEqualityComparer<T>());
+        }
+    }
+
+#endif
+
     public sealed class ConcurrentBagFormatter<T> : CollectionFormatterBase<T, System.Collections.Concurrent.ConcurrentBag<T>>
     {
         protected override int? GetCount(ConcurrentBag<T> sequence)
diff --git a/src/MessagePack.UnityClient/Assets/Scripts/MessagePack/Resolvers/DynamicGenericResolver.cs b/src/MessagePack.UnityClient/Assets/Scripts/MessagePack/Resolvers/DynamicGenericResolver.cs
index bb555243e..dc54e6268 100644
--- a/src/MessagePack.UnityClient/Assets/Scripts/MessagePack/Resolvers/DynamicGenericResolver.cs
+++ b/src/MessagePack.UnityClient/Assets/Scripts/MessagePack/Resolvers/DynamicGenericResolver.cs
@@ -70,6 +70,9 @@ internal static class DynamicGenericResolverGetFormatterHelper
               { typeof(IReadOnlyList<>), typeof(InterfaceReadOnlyListFormatter<>) },
               { typeof(IReadOnlyCollection<>), typeof(InterfaceReadOnlyCollectionFormatter<>) },
               { typeof(ISet<>), typeof(InterfaceSetFormatter<>) },
+#if NET5_0_OR_GREATER
+              { typeof(IReadOnlySet<>), typeof(InterfaceReadOnlySetFormatter<>) },
+#endif
               { typeof(System.Collections.Concurrent.ConcurrentBag<>), typeof(ConcurrentBagFormatter<>) },
               { typeof(System.Collections.Concurrent.ConcurrentQueue<>), typeof(ConcurrentQueueFormatter<>) },
               { typeof(System.Collections.Concurrent.ConcurrentStack<>), typeof(ConcurrentStackFormatter<>) },
diff --git a/src/MessagePack/net5.0/PublicAPI.Unshipped.txt b/src/MessagePack/net5.0/PublicAPI.Unshipped.txt
index 1525d0ccb..519b17eec 100644
--- a/src/MessagePack/net5.0/PublicAPI.Unshipped.txt
+++ b/src/MessagePack/net5.0/PublicAPI.Unshipped.txt
@@ -4,6 +4,8 @@ MessagePack.FormatterNotRegisteredException.FormatterNotRegisteredException(Syst
 MessagePack.Formatters.HalfFormatter
 MessagePack.Formatters.HalfFormatter.Deserialize(ref MessagePack.MessagePackReader reader, MessagePack.MessagePackSerializerOptions options) -> System.Half
 MessagePack.Formatters.HalfFormatter.Serialize(ref MessagePack.MessagePackWriter writer, System.Half value, MessagePack.MessagePackSerializerOptions options) -> void
+MessagePack.Formatters.InterfaceReadOnlySetFormatter<T>
+MessagePack.Formatters.InterfaceReadOnlySetFormatter<T>.InterfaceReadOnlySetFormatter() -> void
 MessagePack.MessagePackReader.MessagePackReader() -> void
 MessagePack.MessagePackSerializerOptions.SequencePool.get -> MessagePack.SequencePool
 MessagePack.MessagePackSerializerOptions.WithPool(MessagePack.SequencePool pool) -> MessagePack.MessagePackSerializerOptions