From 8ff03eda80839189e2ac1df99b89106246c4fd39 Mon Sep 17 00:00:00 2001
From: Stephen Toub <stoub@microsoft.com>
Date: Mon, 17 Jul 2023 17:06:41 -0400
Subject: [PATCH] Dedup OnWriteResume between {ReadOnly}Memory converters

---
 .../Converters/Collection/MemoryConverter.cs  | 36 +------------------
 .../Collection/ReadOnlyMemoryConverter.cs     | 13 ++++---
 2 files changed, 9 insertions(+), 40 deletions(-)

diff --git a/src/libraries/System.Text.Json/src/System/Text/Json/Serialization/Converters/Collection/MemoryConverter.cs b/src/libraries/System.Text.Json/src/System/Text/Json/Serialization/Converters/Collection/MemoryConverter.cs
index 853d8a3159cd0..55f145e535479 100644
--- a/src/libraries/System.Text.Json/src/System/Text/Json/Serialization/Converters/Collection/MemoryConverter.cs
+++ b/src/libraries/System.Text.Json/src/System/Text/Json/Serialization/Converters/Collection/MemoryConverter.cs
@@ -27,41 +27,7 @@ protected override void ConvertCollection(ref ReadStack state, JsonSerializerOpt
 
         protected override bool OnWriteResume(Utf8JsonWriter writer, Memory<T> value, JsonSerializerOptions options, ref WriteStack state)
         {
-            int index = state.Current.EnumeratorIndex;
-
-            JsonConverter<T> elementConverter = GetElementConverter(ref state);
-            ReadOnlySpan<T> valueSpan = value.Span;
-
-            if (elementConverter.CanUseDirectReadOrWrite && state.Current.NumberHandling == null)
-            {
-                // Fast path that avoids validation and extra indirection.
-                for (; index < valueSpan.Length; index++)
-                {
-                    elementConverter.Write(writer, valueSpan[index], options);
-                }
-            }
-            else
-            {
-                for (; index < value.Length; index++)
-                {
-                    T element = valueSpan[index];
-                    if (!elementConverter.TryWrite(writer, element, options, ref state))
-                    {
-                        state.Current.EnumeratorIndex = index;
-                        return false;
-                    }
-
-                    state.Current.EndCollectionElement();
-
-                    if (ShouldFlush(writer, ref state))
-                    {
-                        state.Current.EnumeratorIndex = ++index;
-                        return false;
-                    }
-                }
-            }
-
-            return true;
+            return ReadOnlyMemoryConverter<T>.OnWriteResume(writer, value.Span, options, ref state);
         }
     }
 }
diff --git a/src/libraries/System.Text.Json/src/System/Text/Json/Serialization/Converters/Collection/ReadOnlyMemoryConverter.cs b/src/libraries/System.Text.Json/src/System/Text/Json/Serialization/Converters/Collection/ReadOnlyMemoryConverter.cs
index 6d5a39e750490..b8778c7736baa 100644
--- a/src/libraries/System.Text.Json/src/System/Text/Json/Serialization/Converters/Collection/ReadOnlyMemoryConverter.cs
+++ b/src/libraries/System.Text.Json/src/System/Text/Json/Serialization/Converters/Collection/ReadOnlyMemoryConverter.cs
@@ -26,26 +26,29 @@ protected override void ConvertCollection(ref ReadStack state, JsonSerializerOpt
         }
 
         protected override bool OnWriteResume(Utf8JsonWriter writer, ReadOnlyMemory<T> value, JsonSerializerOptions options, ref WriteStack state)
+        {
+            return OnWriteResume(writer, value.Span, options, ref state);
+        }
+
+        internal static bool OnWriteResume(Utf8JsonWriter writer, ReadOnlySpan<T> value, JsonSerializerOptions options, ref WriteStack state)
         {
             int index = state.Current.EnumeratorIndex;
 
             JsonConverter<T> elementConverter = GetElementConverter(ref state);
-            ReadOnlySpan<T> valueSpan = value.Span;
 
             if (elementConverter.CanUseDirectReadOrWrite && state.Current.NumberHandling == null)
             {
                 // Fast path that avoids validation and extra indirection.
-                for (; index < valueSpan.Length; index++)
+                for (; index < value.Length; index++)
                 {
-                    elementConverter.Write(writer, valueSpan[index], options);
+                    elementConverter.Write(writer, value[index], options);
                 }
             }
             else
             {
                 for (; index < value.Length; index++)
                 {
-                    T element = valueSpan[index];
-                    if (!elementConverter.TryWrite(writer, element, options, ref state))
+                    if (!elementConverter.TryWrite(writer, value[index], options, ref state))
                     {
                         state.Current.EnumeratorIndex = index;
                         return false;