Add SystemTextJsonSerializer base class and relevant extensions met…

…hods

src/Elastic.Transport/Components/Serialization/LowLevelRequestResponseSerializer.cs

@@ -2,33 +2,28 @@
 // Elasticsearch B.V licenses this file to you under the Apache 2.0 License.
 // See the LICENSE file in the project root for more information
 
-using System;
 using System.Collections.Generic;
 using System.Collections.ObjectModel;
-using System.IO;
 using System.Linq;
 using System.Text.Json;
 using System.Text.Json.Serialization;
-using System.Threading;
-using System.Threading.Tasks;
+
 using Elastic.Transport.Extensions;
-using static Elastic.Transport.SerializationFormatting;
 
 namespace Elastic.Transport;
 
 /// <summary>
-/// Default implementation for <see cref="Serializer"/>. This uses <see cref="JsonSerializer"/> from <code>System.Text.Json</code>.
+/// Default low level request/response-serializer implementation for <see cref="Serializer"/> which serializes using
+/// the Microsoft <c>System.Text.Json</c> library
 /// </summary>
-internal sealed class LowLevelRequestResponseSerializer : Serializer
+internal sealed class LowLevelRequestResponseSerializer :
+	SystemTextJsonSerializer
 {
 	/// <summary>
 	/// Provides a static reusable reference to an instance of <see cref="LowLevelRequestResponseSerializer"/> to promote reuse.
 	/// </summary>
 	internal static readonly LowLevelRequestResponseSerializer Instance = new();
 
-	private readonly Lazy<JsonSerializerOptions> _indented;
-	private readonly Lazy<JsonSerializerOptions> _none;
-
 	private IReadOnlyCollection<JsonConverter> AdditionalConverters { get; }
 
 	private IList<JsonConverter> BakedInConverters { get; } = new List<JsonConverter>
@@ -46,94 +41,28 @@ public LowLevelRequestResponseSerializer() : this(null) { }
 	/// <inheritdoc cref="LowLevelRequestResponseSerializer"/>>
 	/// </summary>
 	/// <param name="converters">Add more default converters onto <see cref="JsonSerializerOptions"/> being used</param>
-	public LowLevelRequestResponseSerializer(IEnumerable<JsonConverter>? converters)
-	{
+	public LowLevelRequestResponseSerializer(IEnumerable<JsonConverter>? converters) =>
 		AdditionalConverters = converters != null
 			? new ReadOnlyCollection<JsonConverter>(converters.ToList())
 			: EmptyReadOnly<JsonConverter>.Collection;
-		_indented = new Lazy<JsonSerializerOptions>(() => CreateSerializerOptions(Indented));
-		_none = new Lazy<JsonSerializerOptions>(() => CreateSerializerOptions(None));
-	}
 
 	/// <summary>
 	/// Creates <see cref="JsonSerializerOptions"/> used for serialization.
 	/// Override on a derived serializer to change serialization.
 	/// </summary>
-	public JsonSerializerOptions CreateSerializerOptions(SerializationFormatting formatting)
+	protected override JsonSerializerOptions? CreateJsonSerializerOptions()
 	{
 		var options = new JsonSerializerOptions
 		{
-			DefaultIgnoreCondition = JsonIgnoreCondition.WhenWritingNull,
-			WriteIndented = formatting == Indented,
+			DefaultIgnoreCondition = JsonIgnoreCondition.WhenWritingNull
 		};
+
 		foreach (var converter in BakedInConverters)
 			options.Converters.Add(converter);
+
 		foreach (var converter in AdditionalConverters)
 			options.Converters.Add(converter);
 
 		return options;
-
-	}
-
-	private static bool TryReturnDefault<T>(Stream? stream, out T deserialize)
-	{
-		deserialize = default;
-		return stream == null || stream == Stream.Null || (stream.CanSeek && stream.Length == 0);
-	}
-
-	private JsonSerializerOptions GetFormatting(SerializationFormatting formatting) => formatting == None ? _none.Value : _indented.Value;
-
-	/// <inheritdoc cref="Serializer.Deserialize"/>>
-	public override object Deserialize(Type type, Stream stream)
-	{
-		if (TryReturnDefault(stream, out object deserialize)) return deserialize;
-
-		return JsonSerializer.Deserialize(stream, type, _none.Value)!;
-	}
-
-	/// <inheritdoc cref="Serializer.Deserialize{T}"/>>
-	public override T Deserialize<T>(Stream stream)
-	{
-		if (TryReturnDefault(stream, out T deserialize)) return deserialize;
-
-		return JsonSerializer.Deserialize<T>(stream, _none.Value);
-	}
-
-	/// <inheritdoc cref="Serializer.Serialize{T}"/>>
-	public override void Serialize<T>(T data, Stream stream, SerializationFormatting formatting = None)
-	{
-		using var writer = new Utf8JsonWriter(stream);
-		if (data == null)
-			JsonSerializer.Serialize(writer, null, typeof(object), GetFormatting(formatting));
-		//TODO validate if we can avoid boxing by checking if data is typeof(object)
-		else
-			JsonSerializer.Serialize(writer, data, data.GetType(), GetFormatting(formatting));
-	}
-
-	/// <inheritdoc cref="Serializer.SerializeAsync{T}"/>>
-	public override async Task SerializeAsync<T>(T data, Stream stream, SerializationFormatting formatting = None,
-		CancellationToken cancellationToken = default
-	)
-	{
-		if (data == null)
-			await JsonSerializer.SerializeAsync(stream, null, typeof(object), GetFormatting(formatting), cancellationToken).ConfigureAwait(false);
-		else
-			await JsonSerializer.SerializeAsync(stream, data, data.GetType(), GetFormatting(formatting), cancellationToken).ConfigureAwait(false);
-	}
-
-	/// <inheritdoc cref="Serializer.DeserializeAsync"/>>
-	public override ValueTask<object> DeserializeAsync(Type type, Stream stream, CancellationToken cancellationToken = default)
-	{
-		if (TryReturnDefault(stream, out object deserialize)) return new ValueTask<object>(deserialize);
-
-		return JsonSerializer.DeserializeAsync(stream, type, _none.Value, cancellationToken);
-	}
-
-	/// <inheritdoc cref="Serializer.DeserializeAsync{T}"/>>
-	public override ValueTask<T> DeserializeAsync<T>(Stream stream, CancellationToken cancellationToken = default)
-	{
-		if (TryReturnDefault(stream, out T deserialize)) return new ValueTask<T>(deserialize);
-
-		return JsonSerializer.DeserializeAsync<T>(stream, _none.Value, cancellationToken);
 	}
 }

src/Elastic.Transport/Components/Serialization/SystemTextJsonSerializer.cs

@@ -0,0 +1,168 @@
+// Licensed to Elasticsearch B.V under one or more agreements.
+// Elasticsearch B.V licenses this file to you under the Apache 2.0 License.
+// See the LICENSE file in the project root for more information
+
+using System;
+using System.IO;
+using System.Text.Json;
+using System.Threading;
+using System.Threading.Tasks;
+
+namespace Elastic.Transport;
+
+/// <summary>
+/// An abstract implementation of a transport <see cref="Serializer"/> which serializes using the Microsoft
+/// <c>System.Text.Json</c> library.
+/// </summary>
+public abstract class SystemTextJsonSerializer :
+	Serializer
+{
+	private readonly SemaphoreSlim _semaphore = new(1);
+
+	private bool _initialized;
+	private JsonSerializerOptions? _options;
+	private JsonSerializerOptions? _indentedOptions;
+
+	#region Serializer
+
+	/// <inheritdoc />
+	public override T Deserialize<T>(Stream stream)
+	{
+		Initialize();
+
+		if (TryReturnDefault(stream, out T deserialize))
+			return deserialize;
+
+		return JsonSerializer.Deserialize<T>(stream, _options);
+	}
+
+	/// <inheritdoc />
+	public override object? Deserialize(Type type, Stream stream)
+	{
+		Initialize();
+
+		if (TryReturnDefault(stream, out object deserialize))
+			return deserialize;
+
+		return JsonSerializer.Deserialize(stream, type, _options);
+	}
+
+	/// <inheritdoc />
+	public override ValueTask<T> DeserializeAsync<T>(Stream stream, CancellationToken cancellationToken = default)
+	{
+		Initialize();
+
+		if (TryReturnDefault(stream, out T deserialize))
+			return new ValueTask<T>(deserialize);
+
+		return JsonSerializer.DeserializeAsync<T>(stream, _options, cancellationToken);
+	}
+
+	/// <inheritdoc />
+	public override ValueTask<object?> DeserializeAsync(Type type, Stream stream, CancellationToken cancellationToken = default)
+	{
+		Initialize();
+
+		if (TryReturnDefault(stream, out object deserialize))
+			return new ValueTask<object?>(deserialize);
+
+		return JsonSerializer.DeserializeAsync(stream, type, _options, cancellationToken);
+	}
+
+	/// <inheritdoc />
+	public override void Serialize<T>(T data, Stream writableStream,
+		SerializationFormatting formatting = SerializationFormatting.None)
+	{
+		Initialize();
+
+		JsonSerializer.Serialize(writableStream, data, GetJsonSerializerOptions(formatting));
+	}
+
+	/// <inheritdoc />
+	public override Task SerializeAsync<T>(T data, Stream stream,
+		SerializationFormatting formatting = SerializationFormatting.None,
+		CancellationToken cancellationToken = default)
+	{
+		Initialize();
+
+		return JsonSerializer.SerializeAsync(stream, data, GetJsonSerializerOptions(formatting), cancellationToken);
+	}
+
+	#endregion Serializer
+
+	/// <summary>
+	/// A factory method that can create an instance of <see cref="JsonSerializerOptions"/> that will
+	/// be used when serializing.
+	/// </summary>
+	/// <returns></returns>
+	protected abstract JsonSerializerOptions? CreateJsonSerializerOptions();
+
+	/// <summary>
+	/// A callback function that is invoked after the <see cref="JsonSerializerOptions"/> have been created and the
+	/// serializer got fully initialized.
+	/// </summary>
+	protected virtual void Initialized()
+	{
+	}
+
+	/// <summary>
+	/// Returns the <see cref="JsonSerializerOptions"/> for this serializer, based on the given <paramref name="formatting"/>.
+	/// </summary>
+	/// <param name="formatting">The serialization formatting.</param>
+	/// <returns>The requested <see cref="JsonSerializerOptions"/> or <c>null</c>, if the serializer is not initialized yet.</returns>
+	protected internal JsonSerializerOptions? GetJsonSerializerOptions(SerializationFormatting formatting) => (formatting is SerializationFormatting.None)
+		? _options
+		: _indentedOptions;
+
+	/// <summary>
+	/// Initializes a serializer instance such that its <see cref="JsonSerializerOptions"/> are populated.
+	/// </summary>
+	protected internal void Initialize()
+	{
+		// Exit early, if already initialized
+		if (_initialized)
+			return;
+
+		_semaphore.Wait();
+
+		try
+		{
+			// Exit early, if the current thread lost the race
+			if (_initialized)
+				return;
+
+			var options = CreateJsonSerializerOptions();
+
+			if (options is null)
+			{
+				_options = new JsonSerializerOptions();
+				_indentedOptions = new JsonSerializerOptions
+				{
+					WriteIndented = true
+				};
+			}
+			else
+			{
+				_options = options;
+				_indentedOptions = new JsonSerializerOptions(options)
+				{
+					WriteIndented = true
+				};
+			}
+
+			_initialized = true;
+
+			Initialized();
+		}
+		finally
+		{
+			_semaphore.Release();
+		}
+	}
+
+	private static bool TryReturnDefault<T>(Stream? stream, out T deserialize)
+	{
+		deserialize = default;
+		return (stream is null) || stream == Stream.Null || (stream.CanSeek && stream.Length == 0);
+	}
+}