From 02432e5109b0038f096427721d28e06defe5e7b4 Mon Sep 17 00:00:00 2001
From: JKorf <jankorf91@gmail.com>
Date: Tue, 16 Jul 2024 15:54:11 +0200
Subject: [PATCH] Added small performance improvements in
 SystemTextJsonMessageAccessor

---
 .../SystemTextJson/SystemTextJsonMessageAccessor.cs    | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/CryptoExchange.Net/Converters/SystemTextJson/SystemTextJsonMessageAccessor.cs b/CryptoExchange.Net/Converters/SystemTextJson/SystemTextJsonMessageAccessor.cs
index f0ee044..9bd4439 100644
--- a/CryptoExchange.Net/Converters/SystemTextJson/SystemTextJsonMessageAccessor.cs
+++ b/CryptoExchange.Net/Converters/SystemTextJson/SystemTextJsonMessageAccessor.cs
@@ -242,6 +242,7 @@ namespace CryptoExchange.Net.Converters.SystemTextJson
         {
             _stream?.Dispose();
             _stream = null;
+            _document?.Dispose();
             _document = null;
         }
 
@@ -261,6 +262,14 @@ namespace CryptoExchange.Net.Converters.SystemTextJson
 
             try
             {
+                var firstByte = data.Span[0];
+                if (firstByte != 0x7b && firstByte != 0x5b)
+                {
+                    // Value doesn't start with `{` or `[`, prevent deserialization attempt as it's slow
+                    IsJson = false;
+                    return new CallResult(new ServerError("Not a json value"));
+                }
+
                 _document = JsonDocument.Parse(data);
                 IsJson = true;
                 return new CallResult(null);
@@ -289,6 +298,7 @@ namespace CryptoExchange.Net.Converters.SystemTextJson
         public override void Clear()
         {
             _bytes = null;
+            _document?.Dispose();
             _document = null;
         }
     }