add SerializeLayout and MemoryPackOrderAttribute

Author: neuecc

sandbox/SandboxConsoleApp/ForReadMe.cs

@@ -138,3 +138,24 @@ public partial class Version2
     public long Prop2 { get; set; }
     public int? AddedProp { get; set; }
 }
+
+
+
+[MemoryPackable(GenerateType.Object)]
+public partial class Sonota1
+{
+
+}
+
+[MemoryPackable(SerializeLayout.Sequential)]
+public partial class Sonota2
+{
+
+}
+
+[MemoryPackable(GenerateType.Object, SerializeLayout.Explicit)]
+public partial class Sonota3
+{
+    [MemoryPackOrder(0)]
+    public int MyProperty { get; set; }
+}

src/MemoryPack.Core/Attributes.cs

@@ -1,13 +1,23 @@
-namespace MemoryPack;
+using System.Runtime.InteropServices;
+
+namespace MemoryPack;
 
 [AttributeUsage(AttributeTargets.Class | AttributeTargets.Struct | AttributeTargets.Interface, AllowMultiple = false, Inherited = false)]
 public sealed class MemoryPackableAttribute : Attribute
 {
     public GenerateType GenerateType { get; }
+    public SerializeLayout SerializeLayout { get; }
 
-    public MemoryPackableAttribute(GenerateType generateType = GenerateType.Object)
+    public MemoryPackableAttribute(GenerateType generateType = GenerateType.Object, SerializeLayout serializeLayout = SerializeLayout.Sequential)
     {
         this.GenerateType = generateType;
+        this.SerializeLayout = serializeLayout;
+    }
+
+    public MemoryPackableAttribute(SerializeLayout serializeLayout)
+    {
+        this.GenerateType = GenerateType.Object;
+        this.SerializeLayout = serializeLayout;
     }
 }
 
@@ -18,11 +28,17 @@ public enum GenerateType
     NoGenerate
 }
 
+public enum SerializeLayout
+{
+    Sequential, // default
+    Explicit
+}
+
 [AttributeUsage(AttributeTargets.Class | AttributeTargets.Interface, AllowMultiple = true, Inherited = false)]
 public sealed class MemoryPackUnionAttribute : Attribute
 {
-    public byte Tag { get; set; }
-    public Type Type { get; set; }
+    public byte Tag { get; }
+    public Type Type { get; }
 
     public MemoryPackUnionAttribute(byte tag, Type type)
     {
@@ -31,17 +47,22 @@ public MemoryPackUnionAttribute(byte tag, Type type)
     }
 }
 
-// initial design, does not provide this.
-//[AttributeUsage(AttributeTargets.Field | AttributeTargets.Property, AllowMultiple = false, Inherited = false)]
-//public sealed class MemoryPackGenerateAttribute : Attribute
-//{
-//}
-
 [AttributeUsage(AttributeTargets.Field | AttributeTargets.Property, AllowMultiple = false, Inherited = false)]
 public sealed class MemoryPackAllowSerializeAttribute : Attribute
 {
 }
 
+[AttributeUsage(AttributeTargets.Field | AttributeTargets.Property, AllowMultiple = false, Inherited = false)]
+public sealed class MemoryPackOrderAttribute : Attribute
+{
+    public int Order { get; }
+
+    public MemoryPackOrderAttribute(int order)
+    {
+        this.Order = order;
+    }
+}
+
 // similar naming as System.Text.Json attribtues
 // https://docs.microsoft.com/en-us/dotnet/api/system.text.json.serialization.jsonattribute
 

src/MemoryPack.Generator/MemoryPackGenerator.Parser.cs

@@ -66,6 +66,10 @@ public TypeMeta(INamedTypeSymbol symbol, ReferenceSymbols reference)
         }
         else if (packableCtorArgs.Value.Length != 0)
         {
+            // TODO: MemoryPackable has two attribtue
+            // (SerializeLayout serializeLayout)
+            // (GenerateType generateType = GenerateType.Object, SerializeLayout serializeLayout = SerializeLayout.Sequential)
+            // so check length first and choose which constructor used.
             var ctorValue = packableCtorArgs.Value[0];
             var generateType = ctorValue.Value ?? GenerateType.Object;
             this.GenerateType = (GenerateType)generateType;

src/MemoryPack.Generator/ReferenceSymbols.cs

@@ -10,8 +10,8 @@ public class ReferenceSymbols
     public INamedTypeSymbol MemoryPackableAttribute { get; }
     public INamedTypeSymbol MemoryPackUnionAttribute { get; }
     public INamedTypeSymbol MemoryPackConstructorAttribute { get; }
-    // public INamedTypeSymbol MemoryPackGenerateAttribute { get; }
     public INamedTypeSymbol MemoryPackAllowSerializeAttribute { get; }
+    public INamedTypeSymbol MemoryPackOrderAttribute { get; }
     public INamedTypeSymbol MemoryPackIgnoreAttribute { get; }
     public INamedTypeSymbol MemoryPackIncludeAttribute { get; }
     public INamedTypeSymbol MemoryPackOnSerializingAttribute { get; }
@@ -30,8 +30,8 @@ public ReferenceSymbols(Compilation compilation)
         MemoryPackableAttribute = GetTypeByMetadataName(MemoryPackGenerator.MemoryPackableAttributeFullName);
         MemoryPackUnionAttribute = GetTypeByMetadataName("MemoryPack.MemoryPackUnionAttribute");
         MemoryPackConstructorAttribute = GetTypeByMetadataName("MemoryPack.MemoryPackConstructorAttribute");
-        //MemoryPackGenerateAttribute = GetTypeByMetadataName("MemoryPack.MemoryPackGenerateAttribute");
         MemoryPackAllowSerializeAttribute = GetTypeByMetadataName("MemoryPack.MemoryPackAllowSerializeAttribute");
+        MemoryPackOrderAttribute = GetTypeByMetadataName("MemoryPack.MemoryPackOrderAttribute");
         MemoryPackIgnoreAttribute = GetTypeByMetadataName("MemoryPack.MemoryPackIgnoreAttribute");
         MemoryPackIncludeAttribute = GetTypeByMetadataName("MemoryPack.MemoryPackIncludeAttribute");
         MemoryPackOnSerializingAttribute = GetTypeByMetadataName("MemoryPack.MemoryPackOnSerializing");