fix: BinaryObjects with constant arrays are tagged correctly as well

Author: OleRoss

src/Darp.BinaryObjects.Generator/BinaryMemberInfo.cs

@@ -638,6 +638,9 @@ and not WellKnownTypeKind.SByte
                     and not WellKnownTypeKind.Byte
                     and not WellKnownTypeKind.EnumSByte
                     and not WellKnownTypeKind.EnumByte;
+        // Binary object generation does not depend on the byte length
+        if (typeKind is WellKnownTypeKind.BinaryObject)
+            byteLength = UtilityData.UnknownLength;
         return collectionKind switch
         {
             WellKnownCollectionKind.None =>
@@ -732,6 +735,9 @@ and not WellKnownTypeKind.SByte
                     and not WellKnownTypeKind.Byte
                     and not WellKnownTypeKind.EnumSByte
                     and not WellKnownTypeKind.EnumByte;
+        // Binary object generation does not depend on the byte length
+        if (typeKind is WellKnownTypeKind.BinaryObject)
+            byteLength = UtilityData.UnknownLength;
         return collectionKind switch
         {
             WellKnownCollectionKind.None =>
@@ -1212,7 +1218,7 @@ not null
                         bytesRead = list.Count * {byteLength};
                         return list;
                         """,
-                (WellKnownCollectionKind.List, WellKnownTypeKind.BinaryObject, not null) => (_, _, isLittleEndian) =>
+                (WellKnownCollectionKind.List, WellKnownTypeKind.BinaryObject, _) => (_, _, isLittleEndian) =>
                     $$"""
                       var numberOfElements = source.Length / elementLength;
                       var array = new List<T>(numberOfElements);

src/Darp.BinaryObjects.Generator/BinaryObjectsGenerator.Parser.cs

@@ -424,44 +424,59 @@ out ITypeSymbol? underlyingTypeSymbol
         return true;
     }
 
-    private static bool IsConstant(ITypeSymbol typeSymbol, out int constantLength)
+    private static bool IsConstant(ITypeSymbol typeSymbol, out int totalLength)
     {
         AttributeData? binaryConstantObjectAttribute = typeSymbol
             .GetAttributes()
             .FirstOrDefault(x => x.AttributeClass?.ToDisplayString() == "Darp.BinaryObjects.BinaryConstantAttribute");
         if (binaryConstantObjectAttribute?.ConstructorArguments[0].Value is int value)
         {
-            constantLength = value;
+            totalLength = value;
             return true;
         }
 
-        constantLength = default;
+        totalLength = 0;
         foreach (
-            ITypeSymbol memberTypeSymbol in typeSymbol
+            ISymbol symbol in typeSymbol
                 .GetMembers()
                 .Where(x => x.Kind is SymbolKind.Field or SymbolKind.Property)
                 .Where(x => !x.IsImplicitlyDeclared)
-                .Select(x =>
-                    x switch
-                    {
-                        IFieldSymbol s => s.Type,
-                        IPropertySymbol s => s.Type,
-                        _ => throw new ArgumentOutOfRangeException(nameof(x)),
-                    }
-                )
         )
         {
-            if (
-                memberTypeSymbol.TryGetArrayType(out WellKnownCollectionKind collectionKind, out ITypeSymbol? _)
-                || collectionKind is not WellKnownCollectionKind.None
-            )
-                return false;
+            (bool HasAttribute, int? Length) hasElementCountTuple = symbol
+                .GetAttributes()
+                .Select(a =>
+                {
+                    if (a.AttributeClass?.ToDisplayString() != "Darp.BinaryObjects.BinaryElementCountAttribute")
+                        return (false, 1);
+                    if (
+                        !a.GetArguments()
+                            .ToDictionary(x => x.Key, x => x.Value)
+                            .TryGetValue("length", out TypedConstant lengthValue)
+                    )
+                        return (false, 1);
+                    return (true, (int?)lengthValue.Value);
+                })
+                .FirstOrDefault(x => x.Item1);
+            var arrayLength = hasElementCountTuple.Length ?? 1;
+            ITypeSymbol memberTypeSymbol = symbol switch
+            {
+                IFieldSymbol s => s.Type,
+                IPropertySymbol s => s.Type,
+                _ => throw new ArgumentException($"Invalid symbol type {symbol.ToDisplayString()}"),
+            };
+            if (memberTypeSymbol.TryGetArrayType(out WellKnownCollectionKind _, out ITypeSymbol? arrayTypeSymbol))
+            {
+                if (!hasElementCountTuple.HasAttribute)
+                    return false;
+                memberTypeSymbol = arrayTypeSymbol;
+            }
             WellKnownTypeKind typeKind = GetWellKnownTypeKind(memberTypeSymbol);
             if (typeKind is WellKnownTypeKind.BinaryObject)
                 return false;
             if (!typeKind.TryGetLength(out var length))
                 return false;
-            constantLength += length;
+            totalLength += length * arrayLength;
         }
         return true;
     }

test/Darp.BinaryObjects.Generator.Tests/Snapshots/IntegrationTest.BinaryObject_DefaultAsync#BinaryObjectsGenerator.g.verified.cs

@@ -175,15 +175,17 @@ public static bool TryReadBigEndian(global::System.ReadOnlySpan<byte> source, [g
 /// <remarks> <list type="table">
 /// <item> <term><b>Field</b></term> <description><b>Byte Length</b></description> </item>
 /// <item> <term><see cref="Value"/></term> <description>1</description> </item>
-/// <item> <term><see cref="Array"/></term> <description><see cref="OneArray.GetByteCount()"/></description> </item>
-/// <item> <term> --- </term> <description>1 + <see cref="OneArray.GetByteCount()"/></description> </item>
+/// <item> <term><see cref="Array"/></term> <description>2</description> </item>
+/// <item> <term> --- </term> <description>3</description> </item>
 /// </list> </remarks>
+[global::Darp.BinaryObjects.BinaryConstant(3)]
 public sealed partial record OneBinaryObject : global::Darp.BinaryObjects.IBinaryObject<OneBinaryObject>
 {
     /// <inheritdoc />
+    [global::System.Diagnostics.Contracts.Pure]
     [global::System.Runtime.CompilerServices.MethodImpl(global::System.Runtime.CompilerServices.MethodImplOptions.AggressiveInlining)]
     [global::System.CodeDom.Compiler.GeneratedCodeAttribute("Darp.BinaryObjects.Generator", "GeneratorVersion")]
-    public int GetByteCount() => 1 + this.Array.GetByteCount();
+    public int GetByteCount() => 3;
 
     /// <inheritdoc />
     [global::System.CodeDom.Compiler.GeneratedCodeAttribute("Darp.BinaryObjects.Generator", "GeneratorVersion")]
@@ -194,14 +196,11 @@ public bool TryWriteLittleEndian(global::System.Span<byte> destination, out int
     {
         bytesWritten = 0;
 
-        if (destination.Length < 1)
+        if (destination.Length < 3)
             return false;
         global::Darp.BinaryObjects.Generated.Utilities.WriteBinaryObjectLittleEndian(destination[0..], this.Value);
-        bytesWritten += 1;
-
-        if (!this.Array.TryWriteLittleEndian(destination[1..], out var ___bytesWrittenArray))
-            return false;
-        bytesWritten += ___bytesWrittenArray;
+        global::Darp.BinaryObjects.Generated.Utilities.WriteBinaryObjectLittleEndian(destination[1..], this.Array);
+        bytesWritten += 3;
 
         return true;
     }
@@ -214,14 +213,11 @@ public bool TryWriteBigEndian(global::System.Span<byte> destination, out int byt
     {
         bytesWritten = 0;
 
-        if (destination.Length < 1)
+        if (destination.Length < 3)
             return false;
         global::Darp.BinaryObjects.Generated.Utilities.WriteBinaryObjectBigEndian(destination[0..], this.Value);
-        bytesWritten += 1;
-
-        if (!this.Array.TryWriteBigEndian(destination[1..], out var ___bytesWrittenArray))
-            return false;
-        bytesWritten += ___bytesWrittenArray;
+        global::Darp.BinaryObjects.Generated.Utilities.WriteBinaryObjectBigEndian(destination[1..], this.Array);
+        bytesWritten += 3;
 
         return true;
     }
@@ -236,14 +232,11 @@ public static bool TryReadLittleEndian(global::System.ReadOnlySpan<byte> source,
         bytesRead = 0;
         value = default;
 
-        if (source.Length < 1)
+        if (source.Length < 3)
             return false;
         var ___readValue = global::Darp.BinaryObjects.Generated.Utilities.ReadBinaryObjectLittleEndian<OneBool>(source[0..1]);
-        bytesRead += 1;
-
-        if (!OneArray.TryReadLittleEndian(source[1..], out var ___readArray, out var ___bytesReadArray))
-            return false;
-        bytesRead += ___bytesReadArray;
+        var ___readArray = global::Darp.BinaryObjects.Generated.Utilities.ReadBinaryObjectLittleEndian<OneArray>(source[1..3]);
+        bytesRead += 3;
 
         value = new OneBinaryObject(___readValue, ___readArray);
         return true;
@@ -258,14 +251,11 @@ public static bool TryReadBigEndian(global::System.ReadOnlySpan<byte> source, [g
         bytesRead = 0;
         value = default;
 
-        if (source.Length < 1)
+        if (source.Length < 3)
             return false;
         var ___readValue = global::Darp.BinaryObjects.Generated.Utilities.ReadBinaryObjectBigEndian<OneBool>(source[0..1]);
-        bytesRead += 1;
-
-        if (!OneArray.TryReadBigEndian(source[1..], out var ___readArray, out var ___bytesReadArray))
-            return false;
-        bytesRead += ___bytesReadArray;
+        var ___readArray = global::Darp.BinaryObjects.Generated.Utilities.ReadBinaryObjectBigEndian<OneArray>(source[1..3]);
+        bytesRead += 3;
 
         value = new OneBinaryObject(___readValue, ___readArray);
         return true;