Merge pull request #12 from Cysharp/explicit-order

Add Explicit layout feature

Author: neuecc

README.md

@@ -126,7 +126,7 @@ All members must be memorypack-serializable, if not, code generator reports erro
 
 ![image](https://user-images.githubusercontent.com/46207/192413557-8a47d668-5339-46c5-a3da-a77841666f81.png)
 
-MemoryPack has 24 diagnostics rules(`MEMPACK001` to `MEMPACK024`) to be define comfortably.
+MemoryPack has 24 diagnostics rules(`MEMPACK001` to `MEMPACK026`) to be define comfortably.
 
 If target type is defined MemoryPack serialization externally and registered, use `[MemoryPackAllowSerialize]` to silent diagnostics.
 
@@ -141,6 +141,20 @@ public partial class Sample2
 
 Member order is **important**, MemoryPack does not serialize any member-name and other tags, serialize in the declared order. If the type is inherited, serialize in the order of parent → child. Member orders can not change for the deserialization. For the schema evolution, see [Version tolerant](#version-tolerant)  section.
 
+Default order is sequential but you can choose explicit layout with `[MemoryPackable(SerializeLayout.Explicit)]` and `[MemoryPackOrder()]`.
+
+```csharp
+// serialize Prop0 -> Prop1
+[MemoryPackable(SerializeLayout.Explicit)]
+public partial class SampleExplicitOrder
+{
+    [MemoryPackOrder(1)]
+    public int Prop1 { get; set; }
+    [MemoryPackOrder(0)]
+    public int Prop0 { get; set; }
+}
+```
+
 ### Constructor selection
 
 MemoryPack supports parameterized constructor not only parameterless constructor. The selection of the constructor follows these rules. Both class and struct follows same.

sandbox/SandboxConsoleApp/ForReadMe.cs

@@ -138,3 +138,13 @@ public partial class Version2
     public long Prop2 { get; set; }
     public int? AddedProp { get; set; }
 }
+
+
+[MemoryPackable(SerializeLayout.Explicit)]
+public partial class SampleExplicitOrder
+{
+    [MemoryPackOrder(1)]
+    public int Prop1 { get; set; }
+    [MemoryPackOrder(0)]
+    public int Prop0 { get; set; }
+}

sandbox/SandboxConsoleApp/Program.cs

@@ -20,8 +20,10 @@
 using System.Text;
 using System.Xml.Linq;
 
+var a = int.MaxValue;
+var b = ~a;
+Console.WriteLine(b);
 
-Console.WriteLine("foo");
 
 // ---
 
@@ -43,6 +45,33 @@
 
 
 
+[MemoryPackable(GenerateType.Object)]
+public partial class Sonota1
+{
+    // public NoSerializableObject? MyProperty { get; set; }
+}
+
+public class NoSerializableObject
+{
+
+}
+
+[MemoryPackable(SerializeLayout.Explicit)]
+public partial class Sonota2
+{
+    [MemoryPackOrder(1)]
+    public int MyProperty1 { get; set; }
+    [MemoryPackOrder(0)]
+    public int MyProperty2 { get; set; }
+}
+
+[MemoryPackable(GenerateType.Object, SerializeLayout.Explicit)]
+public partial class Sonota3
+{
+    [MemoryPackOrder(0)]
+    public int MyProperty { get; set; }
+}
+
 
 
 

src/MemoryPack.Core/Attributes.cs

@@ -1,13 +1,27 @@
-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; }
+
+    // ctor parameter count is used in MemoryPackGenerator.Parser TypeMeta for detect which ctor used.
+    // if modify ctor, be careful.
 
-    public MemoryPackableAttribute(GenerateType generateType = GenerateType.Object)
+    public MemoryPackableAttribute(GenerateType generateType = GenerateType.Object, SerializeLayout serializeLayout = SerializeLayout.Sequential)
     {
         this.GenerateType = generateType;
+        this.SerializeLayout = serializeLayout;
+    }
+
+    // set SerializeLayout only allows Object
+    public MemoryPackableAttribute(SerializeLayout serializeLayout)
+    {
+        this.GenerateType = GenerateType.Object;
+        this.SerializeLayout = serializeLayout;
     }
 }
 
@@ -18,11 +32,17 @@ 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 +51,22 @@ 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/GenerateType.cs renamed to src/MemoryPack.Generator/CoreEnums.cs

@@ -7,3 +7,9 @@ public enum GenerateType
     Collection,
     NoGenerate
 }
+
+public enum SerializeLayout
+{
+    Sequential, // default
+    Explicit
+}

src/MemoryPack.Generator/DiagnosticDescriptors.cs

@@ -204,4 +204,20 @@ internal static class DiagnosticDescriptors
         category: Category,
         defaultSeverity: DiagnosticSeverity.Error,
         isEnabledByDefault: true);
+
+    public static readonly DiagnosticDescriptor AllMembersMustAnnotateOrder = new(
+        id: "MEMPACK025",
+        title: "All members must annotate MemoryPackOrder when SerializeLayout.Explicit",
+        messageFormat: "The MemoryPackable object '{0}' member '{1}' is not annotated MemoryPackOrder",
+        category: Category,
+        defaultSeverity: DiagnosticSeverity.Error,
+        isEnabledByDefault: true);
+
+    public static readonly DiagnosticDescriptor AllMembersMustBeContinuousNumber = new(
+        id: "MEMPACK026",
+        title: "All MemoryPackOrder members must be continuous number from zero",
+        messageFormat: "The MemoryPackable object '{0}' member '{1}' is not continuous number from zero",
+        category: Category,
+        defaultSeverity: DiagnosticSeverity.Error,
+        isEnabledByDefault: true);
 }