1 files changed, 20 insertions, 16 deletions

diff --git a/Emby.Server.Implementations/AppBase/ConfigurationHelper.cs b/Emby.Server.Implementations/AppBase/ConfigurationHelper.cs
index 90b97061f..3a916e5c0 100644
--- a/Emby.Server.Implementations/AppBase/ConfigurationHelper.cs
+++ b/Emby.Server.Implementations/AppBase/ConfigurationHelper.cs
@@ -6,13 +6,13 @@ using MediaBrowser.Model.Serialization;
 namespace Emby.Server.Implementations.AppBase
 {
     /// <summary>
-    /// Class ConfigurationHelper
+    /// Class ConfigurationHelper.
     /// </summary>
     public static class ConfigurationHelper
     {
         /// <summary>
         /// Reads an xml configuration file from the file system
-        /// It will immediately re-serialize and save if new serialization data is available due to property changes
+        /// It will immediately re-serialize and save if new serialization data is available due to property changes.
         /// </summary>
         /// <param name="type">The type.</param>
         /// <param name="path">The path.</param>
@@ -22,7 +22,7 @@ namespace Emby.Server.Implementations.AppBase
         {
             object configuration;
 
-            byte[] buffer = null;
+            byte[]? buffer = null;
 
             // Use try/catch to avoid the extra file system lookup using File.Exists
             try
@@ -33,27 +33,31 @@ namespace Emby.Server.Implementations.AppBase
             }
             catch (Exception)
             {
-                configuration = Activator.CreateInstance(type);
+                // Note: CreateInstance returns null for Nullable<T>, e.g. CreateInstance(typeof(int?)) returns null.
+                configuration = Activator.CreateInstance(type)!;
             }
 
-            using (var stream = new MemoryStream())
+            using var stream = new MemoryStream(buffer?.Length ?? 0);
+            xmlSerializer.SerializeToStream(configuration, stream);
+
+            // Take the object we just got and serialize it back to bytes
+            Span<byte> newBytes = stream.GetBuffer().AsSpan(0, (int)stream.Length);
+
+            // If the file didn't exist before, or if something has changed, re-save
+            if (buffer == null || !newBytes.SequenceEqual(buffer))
             {
-                xmlSerializer.SerializeToStream(configuration, stream);
+                var directory = Path.GetDirectoryName(path) ?? throw new ArgumentException($"Provided path ({path}) is not valid.", nameof(path));
 
-                // Take the object we just got and serialize it back to bytes
-                var newBytes = stream.ToArray();
+                Directory.CreateDirectory(directory);
 
-                // If the file didn't exist before, or if something has changed, re-save
-                if (buffer == null || !buffer.SequenceEqual(newBytes))
+                // Save it after load in case we got new items
+                using (var fs = new FileStream(path, FileMode.Create, FileAccess.Write, FileShare.None))
                 {
-                    Directory.CreateDirectory(Path.GetDirectoryName(path));
-
-                    // Save it after load in case we got new items
-                    File.WriteAllBytes(path, newBytes);
+                    fs.Write(newBytes);
                 }
-
-                return configuration;
             }
+
+            return configuration;
         }
     }
 }