Add SystemTextJsonSerializer base class and relevant extensions methods

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/Serializer.cs

@@ -32,6 +32,8 @@ public abstract class Serializer
  /// <inheritdoc cref="Deserialize"/>
  public abstract ValueTask<T> DeserializeAsync<T>(Stream stream, CancellationToken cancellationToken = default);
 
+ // TODO: Overloads for (object?, Type) inputs
+
  /// <summary>
  /// Serialize an instance of <typeparamref name="T"/> to <paramref name="stream"/> using <paramref name="formatting"/>.
  /// </summary>

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

@@ -0,0 +1,169 @@
+// 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 = SerializationFormatting.None) =>
+ (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);
+ }
+}