Creating new TypeName without reparsing + usage in NRBF

src/libraries/System.Formats.Nrbf/src/Resources/Strings.resx

@@ -159,4 +159,7 @@
   <data name="NotSupported_NonZeroOffsets" xml:space="preserve">
     <value>Only arrays with zero offsets are supported.</value>
   </data>
+  <data name="Serialization_InvalidAssemblyName" xml:space="preserve">
+    <value>Invalid assembly name: `{0}`.</value>
+  </data>
 </root>

src/libraries/System.Formats.Nrbf/src/System/Formats/Nrbf/ArraySingleObjectRecord.cs

@@ -16,14 +16,12 @@ namespace System.Formats.Nrbf;
 /// </remarks>
 internal sealed class ArraySingleObjectRecord : SZArrayRecord<object?>
 {
-    private static TypeName? s_typeName;
-
     private ArraySingleObjectRecord(ArrayInfo arrayInfo) : base(arrayInfo) => Records = [];
 
     public override SerializationRecordType RecordType => SerializationRecordType.ArraySingleObject;
 
     public override TypeName TypeName
-        => s_typeName ??= TypeName.Parse(("System.Object[], " + TypeNameExtensions.CoreLibAssemblyName).AsSpan());
+        => TypeNameHelpers.GetPrimitiveSZArrayTypeName(TypeNameHelpers.ObjectPrimitiveType);
 
     private List<SerializationRecord> Records { get; }
 

src/libraries/System.Formats.Nrbf/src/System/Formats/Nrbf/ArraySinglePrimitiveRecord.cs

@@ -24,8 +24,6 @@ namespace System.Formats.Nrbf;
 internal sealed class ArraySinglePrimitiveRecord<T> : SZArrayRecord<T>
     where T : unmanaged
 {
-    private static TypeName? s_typeName;
-
     internal ArraySinglePrimitiveRecord(ArrayInfo arrayInfo, IReadOnlyList<T> values) : base(arrayInfo)
     {
         Values = values;
@@ -35,8 +33,7 @@ internal ArraySinglePrimitiveRecord(ArrayInfo arrayInfo, IReadOnlyList<T> values
     public override SerializationRecordType RecordType => SerializationRecordType.ArraySinglePrimitive;
 
     /// <inheritdoc />
-    public override TypeName TypeName
-        => s_typeName ??= TypeName.Parse((typeof(T[]).FullName + "," + TypeNameExtensions.CoreLibAssemblyName).AsSpan());
+    public override TypeName TypeName => TypeNameHelpers.GetPrimitiveSZArrayTypeName(TypeNameHelpers.GetPrimitiveType<T>());
 
     internal IReadOnlyList<T> Values { get; }
 

src/libraries/System.Formats.Nrbf/src/System/Formats/Nrbf/ArraySingleStringRecord.cs

@@ -16,15 +16,12 @@ namespace System.Formats.Nrbf;
 /// </remarks>
 internal sealed class ArraySingleStringRecord : SZArrayRecord<string?>
 {
-    private static TypeName? s_typeName;
-
     private ArraySingleStringRecord(ArrayInfo arrayInfo) : base(arrayInfo) => Records = [];
 
     public override SerializationRecordType RecordType => SerializationRecordType.ArraySingleString;
 
     /// <inheritdoc />
-    public override TypeName TypeName
-        => s_typeName ??= TypeName.Parse(("System.String[], " + TypeNameExtensions.CoreLibAssemblyName).AsSpan());
+    public override TypeName TypeName => TypeNameHelpers.GetPrimitiveSZArrayTypeName(PrimitiveType.String);
 
     private List<SerializationRecord> Records { get; }
 

src/libraries/System.Formats.Nrbf/src/System/Formats/Nrbf/BinaryLibraryRecord.cs

@@ -2,6 +2,7 @@
 // The .NET Foundation licenses this file to you under the MIT license.
 
 using System.Diagnostics;
+using System.Formats.Nrbf.Utils;
 using System.IO;
 using System.Reflection.Metadata;
 
@@ -15,7 +16,13 @@ namespace System.Formats.Nrbf;
 /// </remarks>
 internal sealed class BinaryLibraryRecord : SerializationRecord
 {
-    private BinaryLibraryRecord(SerializationRecordId libraryId, string libraryName)
+    private BinaryLibraryRecord(SerializationRecordId libraryId, string rawLibraryName)
+    {
+        Id = libraryId;
+        RawLibraryName = rawLibraryName;
+    }
+
+    private BinaryLibraryRecord(SerializationRecordId libraryId, AssemblyNameInfo libraryName)
     {
         Id = libraryId;
         LibraryName = libraryName;
@@ -32,11 +39,27 @@ public override TypeName TypeName
         }
     }
 
-    internal string LibraryName { get; }
+    internal string? RawLibraryName { get; }
+
+    internal AssemblyNameInfo? LibraryName { get; }
 
     /// <inheritdoc />
     public override SerializationRecordId Id { get; }
 
-    internal static BinaryLibraryRecord Decode(BinaryReader reader)
-        => new(SerializationRecordId.Decode(reader), reader.ReadString());
+    internal static BinaryLibraryRecord Decode(BinaryReader reader, PayloadOptions options)
+    {
+        SerializationRecordId id = SerializationRecordId.Decode(reader);
+        string rawName = reader.ReadString();
+
+        if (AssemblyNameInfo.TryParse(rawName.AsSpan(), out AssemblyNameInfo? assemblyNameInfo))
+        {
+            return new BinaryLibraryRecord(id, assemblyNameInfo);
+        }
+        else if (!options.UndoTruncatedTypeNames)
+        {
+            ThrowHelper.ThrowInvalidAssemblyName(rawName);
+        }
+
+        return new BinaryLibraryRecord(id, rawName);
+    }
 }

src/libraries/System.Formats.Nrbf/src/System/Formats/Nrbf/MemberTypeInfo.cs

@@ -142,63 +142,25 @@ internal TypeName GetArrayTypeName(ArrayInfo arrayInfo)
     {
         (BinaryType binaryType, object? additionalInfo) = Infos[0];
 
-        switch (binaryType)
+        TypeName elementTypeName = binaryType switch
         {
-            case BinaryType.String:
-                return typeof(string).BuildCoreLibArrayTypeName(arrayInfo.Rank);
-            case BinaryType.StringArray:
-                return typeof(string[]).BuildCoreLibArrayTypeName(arrayInfo.Rank);
-            case BinaryType.Object:
-                return typeof(object).BuildCoreLibArrayTypeName(arrayInfo.Rank);
-            case BinaryType.ObjectArray:
-                return typeof(object[]).BuildCoreLibArrayTypeName(arrayInfo.Rank);
-            case BinaryType.Primitive:
-                Type primitiveType = ((PrimitiveType)additionalInfo!) switch
-                {
-                    PrimitiveType.Boolean => typeof(bool),
-                    PrimitiveType.Byte => typeof(byte),
-                    PrimitiveType.Char => typeof(char),
-                    PrimitiveType.Decimal => typeof(decimal),
-                    PrimitiveType.Double => typeof(double),
-                    PrimitiveType.Int16 => typeof(short),
-                    PrimitiveType.Int32 => typeof(int),
-                    PrimitiveType.Int64 => typeof(long),
-                    PrimitiveType.SByte => typeof(sbyte),
-                    PrimitiveType.Single => typeof(float),
-                    PrimitiveType.TimeSpan => typeof(TimeSpan),
-                    PrimitiveType.DateTime => typeof(DateTime),
-                    PrimitiveType.UInt16 => typeof(ushort),
-                    PrimitiveType.UInt32 => typeof(uint),
-                    _ => typeof(ulong),
-                };
-
-                return primitiveType.BuildCoreLibArrayTypeName(arrayInfo.Rank);
-            case BinaryType.PrimitiveArray:
-                Type primitiveArrayType = ((PrimitiveType)additionalInfo!) switch
-                {
-                    PrimitiveType.Boolean => typeof(bool[]),
-                    PrimitiveType.Byte => typeof(byte[]),
-                    PrimitiveType.Char => typeof(char[]),
-                    PrimitiveType.Decimal => typeof(decimal[]),
-                    PrimitiveType.Double => typeof(double[]),
-                    PrimitiveType.Int16 => typeof(short[]),
-                    PrimitiveType.Int32 => typeof(int[]),
-                    PrimitiveType.Int64 => typeof(long[]),
-                    PrimitiveType.SByte => typeof(sbyte[]),
-                    PrimitiveType.Single => typeof(float[]),
-                    PrimitiveType.TimeSpan => typeof(TimeSpan[]),
-                    PrimitiveType.DateTime => typeof(DateTime[]),
-                    PrimitiveType.UInt16 => typeof(ushort[]),
-                    PrimitiveType.UInt32 => typeof(uint[]),
-                    _ => typeof(ulong[]),
-                };
-
-                return primitiveArrayType.BuildCoreLibArrayTypeName(arrayInfo.Rank);
-            case BinaryType.SystemClass:
-                return ((TypeName)additionalInfo!).BuildArrayTypeName(arrayInfo.Rank);
-            default:
-                Debug.Assert(binaryType is BinaryType.Class, "The parsers should reject other inputs");
-                return (((ClassTypeInfo)additionalInfo!).TypeName).BuildArrayTypeName(arrayInfo.Rank);
-        }
+            BinaryType.String => TypeNameHelpers.GetPrimitiveTypeName(PrimitiveType.String),
+            BinaryType.StringArray => TypeNameHelpers.GetPrimitiveSZArrayTypeName(PrimitiveType.String),
+            BinaryType.Primitive => TypeNameHelpers.GetPrimitiveTypeName((PrimitiveType)additionalInfo!),
+            BinaryType.PrimitiveArray => TypeNameHelpers.GetPrimitiveSZArrayTypeName((PrimitiveType)additionalInfo!),
+            BinaryType.Object => TypeNameHelpers.GetPrimitiveTypeName(TypeNameHelpers.ObjectPrimitiveType),
+            BinaryType.ObjectArray => TypeNameHelpers.GetPrimitiveSZArrayTypeName(TypeNameHelpers.ObjectPrimitiveType),
+            BinaryType.SystemClass => (TypeName)additionalInfo!,
+            _ => ((ClassTypeInfo)additionalInfo!).TypeName,
+        };
+
+        // In general, arrayRank == 1 may have two different meanings:
+        // - [] is a single dimension and zero-indexed array (SZArray)
+        // - [*] is single dimension, custom offset array.
+        // Custom offset arrays are not supported by design, so in our case it's always SZArray.
+        // That is why we don't call TypeName.MakeArrayTypeName(1) because it would create [*] instead of [] name.
+        return arrayInfo.Rank == 1
+            ? elementTypeName.MakeArrayTypeName()
+            : elementTypeName.MakeArrayTypeName(arrayInfo.Rank);
     }
 }

src/libraries/System.Formats.Nrbf/src/System/Formats/Nrbf/NrbfDecoder.cs

@@ -227,7 +227,7 @@ private static SerializationRecord DecodeNext(BinaryReader reader, RecordMap rec
             SerializationRecordType.ArraySinglePrimitive => DecodeArraySinglePrimitiveRecord(reader),
             SerializationRecordType.ArraySingleString => ArraySingleStringRecord.Decode(reader),
             SerializationRecordType.BinaryArray => BinaryArrayRecord.Decode(reader, recordMap, options),
-            SerializationRecordType.BinaryLibrary => BinaryLibraryRecord.Decode(reader),
+            SerializationRecordType.BinaryLibrary => BinaryLibraryRecord.Decode(reader, options),
             SerializationRecordType.BinaryObjectString => BinaryObjectStringRecord.Decode(reader),
             SerializationRecordType.ClassWithId => ClassWithIdRecord.Decode(reader, recordMap),
             SerializationRecordType.ClassWithMembersAndTypes => ClassWithMembersAndTypesRecord.Decode(reader, recordMap, options),

src/libraries/System.Formats.Nrbf/src/System/Formats/Nrbf/PrimitiveTypeRecordOfT.cs

@@ -25,8 +25,6 @@ namespace System.Formats.Nrbf;
 [DebuggerDisplay("{Value}")]
 public abstract class PrimitiveTypeRecord<T> : PrimitiveTypeRecord
 {
-    private static TypeName? s_typeName;
-
     private protected PrimitiveTypeRecord(T value) => Value = value;
 
     /// <summary>
@@ -36,8 +34,7 @@ public abstract class PrimitiveTypeRecord<T> : PrimitiveTypeRecord
     public new T Value { get; }
 
     /// <inheritdoc />
-    public override TypeName TypeName
-        => s_typeName ??= TypeName.Parse(typeof(T).FullName.AsSpan()).WithCoreLibAssemblyName();
+    public override TypeName TypeName => TypeNameHelpers.GetPrimitiveTypeName(TypeNameHelpers.GetPrimitiveType<T>());
 
     internal override object? GetValue() => Value;
 }

src/libraries/System.Formats.Nrbf/src/System/Formats/Nrbf/Utils/ThrowHelper.cs

@@ -23,6 +23,9 @@ internal static void ThrowMaxArrayLength(long limit, long actual)
     internal static void ThrowArrayContainedNulls()
         => throw new SerializationException(SR.Serialization_ArrayContainedNulls);
 
+    internal static void ThrowInvalidAssemblyName(string rawName)
+        => throw new SerializationException(SR.Format(SR.Serialization_InvalidAssemblyName, rawName));
+
     internal static void ThrowEndOfStreamException()
         => throw new EndOfStreamException();