From 13d3f7d9d94ab25dd0d513603cb9d3c4b240c735 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Franti=C5=A1ek=20Boh=C3=A1=C4=8Dek?=
 <fandabohacek@gmail.com>
Date: Sun, 2 Jan 2022 14:31:42 +0100
Subject: [PATCH] feat: add extensions for checking type nullability

---
 .../Extensions/TypeSymbolExtensions.cs        | 36 +++++++++++++++++++
 .../Extensions/TypeSyntaxExtensions.cs        | 25 +++++++++++++
 2 files changed, 61 insertions(+)
 create mode 100644 Core/NosSmooth.PacketSerializersGenerator/Extensions/TypeSymbolExtensions.cs
 create mode 100644 Core/NosSmooth.PacketSerializersGenerator/Extensions/TypeSyntaxExtensions.cs

diff --git a/Core/NosSmooth.PacketSerializersGenerator/Extensions/TypeSymbolExtensions.cs b/Core/NosSmooth.PacketSerializersGenerator/Extensions/TypeSymbolExtensions.cs
new file mode 100644
index 0000000..f05c7a1
--- /dev/null
+++ b/Core/NosSmooth.PacketSerializersGenerator/Extensions/TypeSymbolExtensions.cs
@@ -0,0 +1,36 @@
+//
+//  TypeSymbolExtensions.cs
+//
+//  Copyright (c) František Boháček. All rights reserved.
+//  Licensed under the MIT license. See LICENSE file in the project root for full license information.
+
+using Microsoft.CodeAnalysis;
+
+namespace NosSmooth.PacketSerializersGenerator.Extensions;
+
+/// <summary>
+/// Extension methods for <see cref="ITypeSymbol"/>.
+/// </summary>
+public static class TypeSymbolExtensions
+{
+    /// <summary>
+    /// Gets whether the type symbol is nullable.
+    /// </summary>
+    /// <param name="typeSymbol">The type symbol.</param>
+    /// <returns>Whether the type symbol is nullable. Returns null if not possible to determine.</returns>
+    public static bool? IsNullable(this ITypeSymbol typeSymbol)
+    {
+        if (typeSymbol.NullableAnnotation == NullableAnnotation.Annotated || typeSymbol.Name == "Nullable")
+        {
+            return true;
+        }
+
+        if (typeSymbol.IsValueType)
+        {
+            return false;
+        }
+
+        // cannot determine if not nullable from reference type.
+        return null;
+    }
+}
\ No newline at end of file
diff --git a/Core/NosSmooth.PacketSerializersGenerator/Extensions/TypeSyntaxExtensions.cs b/Core/NosSmooth.PacketSerializersGenerator/Extensions/TypeSyntaxExtensions.cs
new file mode 100644
index 0000000..d95bbbc
--- /dev/null
+++ b/Core/NosSmooth.PacketSerializersGenerator/Extensions/TypeSyntaxExtensions.cs
@@ -0,0 +1,25 @@
+//
+//  TypeSyntaxExtensions.cs
+//
+//  Copyright (c) František Boháček. All rights reserved.
+//  Licensed under the MIT license. See LICENSE file in the project root for full license information.
+
+using Microsoft.CodeAnalysis.CSharp.Syntax;
+
+namespace NosSmooth.PacketSerializersGenerator.Extensions;
+
+/// <summary>
+/// Extension methods for <see cref="TypeSyntax"/>.
+/// </summary>
+public static class TypeSyntaxExtensions
+{
+    /// <summary>
+    /// Gets whether the type syntax is nullable.
+    /// </summary>
+    /// <param name="typeSyntax">The type syntax.</param>
+    /// <returns>Whether the type syntax is nullable.</returns>
+    public static bool IsNullable(this TypeSyntax typeSyntax)
+    {
+        return typeSyntax is NullableTypeSyntax;
+    }
+}
\ No newline at end of file
-- 
2.49.0