RecordDeconstructor

Record deconstructor extracts each field value into a tuple.

IWriterToRef<MyClass, (int, string)> myClassDeconstructor;
IWriterToRef<MyStruct, (int, string)> myStructDeconstructor;

Example class and struct.

public record MyClass(int Id, string Label);
public record struct MyStruct(int Id, string Label);

Creating a deconstructor

Deconstructor can be created with a delegate adapter.

var myClassDeconstructor = DelegateWriter.Reader<MyClass, (int, string)>(record => (record.Id, record.Label));
var myStructDeconstructor = DelegateWriter.Reader<MyStruct, (int, string)>(record => (record.Id, record.Label));

Simple deconstructor implements just IWriterToRef<Tuple,Record>.

IWriterToRef<MyClass, (int, string)> myClassDeconstructor = new MyClassDeconstructor1();
IWriterToRef<MyStruct, (int, string)> myStructDeconstructor = new MyStructDeconstructor1();

/// <summary></summary>
public class MyClassDeconstructor1 : WriterToRef<MyClass, (int, string)>
{
    /// <summary></summary>
    public override bool TryWrite(MyClass from, ref (int, string) to, IServiceProvider? context = null)
    {
        to.Item1 = from.Id;
        to.Item2 = from.Label;
        return true;
    }
}

/// <summary></summary>
public class MyStructDeconstructor1 : WriterToRef<MyStruct, (int, string)>
{
    /// <summary></summary>
    public override bool TryWrite(MyStruct from, ref (int, string) to, IServiceProvider? context = null)
    {
        to.Item1 = from.Id;
        to.Item2 = from.Label;
        return true;
    }
}

RecordDeconstructorBase can be used for base class for deconstructor. Base class has more type-casting features.

IWriterToRef<MyClass, (int, string)> myClassDeconstructor = new MyClassDeconstructor2();
IWriterToRef<MyStruct, (int, string)> myStructDeconstructor = new MyStructDeconstructor2();

/// <summary></summary>
public class MyClassDeconstructor2 : RecordDeconstructorBase<MyClass, (int, string)>
{
    /// <summary></summary>
    public override bool TryWrite(MyClass from, ref (int, string) to, IServiceProvider? context = null)
    {
        to.Item1 = from.Id;
        to.Item2 = from.Label;
        return true;
    }
}

/// <summary></summary>
public class MyStructDeconstructor2 : RecordDeconstructorBase<MyStruct, (int, string)>
{
    /// <summary></summary>
    public override bool TryWrite(MyStruct from, ref (int, string) to, IServiceProvider? context = null)
    {
        to.Item1 = from.Id;
        to.Item2 = from.Label;
        return true;
    }
}

RecordDeconstructorRequest(Type) builds a deconstructor for record-like types using service stack's handlers.

RecordDeconstructorRequest myClassRequest = new RecordDeconstructorRequest(typeof(MyClass));
RecordDeconstructorRequest myStructRequest = new RecordDeconstructorRequest(typeof(MyStruct));
IWriterToRef<MyClass, (int, string)> myClassDeconstructor = AccessorServices.Instance.GetRequired<RecordDeconstructorRequest, IWriterToRef<MyClass, (int, string)>>(myClassRequest);
IWriterToRef<MyStruct, (int, string)> myStructDeconstructor = AccessorServices.Instance.GetRequired<RecordDeconstructorRequest, IWriterToRef<MyStruct, (int, string)>>(myStructRequest);

RecordDeconstructorRequest(IRecordDescription) builds a deconstructor from record description.

IRecordDescription myClassDescription = new RecordDescription().Read(typeof(MyClass)).AssignConstructors().ChooseConstruction().SetReadOnly();
RecordDeconstructorRequest myClassRequest = new RecordDeconstructorRequest(myClassDescription);
IWriterToRef<MyClass, (int, string)> myClassDeconstructor = AccessorServices.Instance.GetRequired<RecordDeconstructorRequest, IWriterToRef<MyClass, (int, string)>>(myClassRequest);

Usage

Deconstructor creates tuple-value (int, string) from a record.

IWriterToRef<MyClass, (int, string)> myClassDeconstructor = new MyClassDeconstructor2();
IWriterToRef<MyStruct, (int, string)> myStructDeconstructor = new MyStructDeconstructor2();

Deconstructor can be typecasted to e.g. IWriterBase<object, object>. Tuple values can be written right into a box in heap.

MyClass myClass = new MyClass(5, "Hello");
(int, string) tuple1 = myClassDeconstructor.Read(myClass);
MyStruct myStruct = new MyStruct(5, "Hello");
(int, string) tuple2 = myClassDeconstructor.Read(myClass);

// Create record box
object box = myStruct;

// Read tuple box
object tupleBox = null!;
myStructDeconstructor.TypeCast<object, object>().WriteAs<object, object>(box, ref tupleBox);

Or a new box can be created.

tupleBox = myStructDeconstructor.TypeCast<object, object>().ReadAs<object, object>(box);

Custom deconstructor builder

Custom handler can front-run RecordDeconstructorRequest.

public class MyClassDeconstructorBuilder : IHandler<RecordDeconstructorRequest, IWriterBase>
{
    [Order(-100)]
    public void Handle(IQuery<RecordDeconstructorRequest, IWriterBase> query)
    {
        // Already handled
        if (query.Handled()) return;

        // Place type here
        Type? recordType = null;
        //
        if (query.Request.Record is IRecordDescription recordDescription1) recordType = recordDescription1?.Type;
        //
        else if (query.Request.Record is Type type1) recordType = type1;
        //
        else return;

        // This handler only handles "MyClass"
        if (recordType == null || !recordType.Equals(typeof(MyClass))) return;
        // Assign constructor
        query.Response.SetValue(new MyClassDeconstructor2());

    }
}

// Create service
IService service = Services.Create((AccessorServices.Handlers, new MyClassDeconstructorBuilder()), CachePolicies.Default);
// Constructor request
RecordDeconstructorRequest myClassRequest = new RecordDeconstructorRequest(typeof(MyClass));
// Get deconstructor
IWriterToRef<MyClass, (int, string)> myClassDeconstructor =
    service.GetRequired<RecordDeconstructorRequest, IWriterToRef<MyClass, (int, string)>>(myClassRequest);
//
(int, string) tuple = myClassDeconstructor.Read(new MyClass(80, "A"));

Full Example

Full example

using System;
using Avalanche.Accessor;
using Avalanche.Service;
using Avalanche.Utilities;
using Avalanche.Utilities.Record;
using Avalanche.Writer;

public class recorddeconstructor
{
    public static void Run()
    {
        {
#pragma warning disable CS0168
            // <01>
            IWriterToRef<MyClass, (int, string)> myClassDeconstructor;
            IWriterToRef<MyStruct, (int, string)> myStructDeconstructor;
            // </01>
#pragma warning restore CS0168
        }
        {
            // <11>
            var myClassDeconstructor = DelegateWriter.Reader<MyClass, (int, string)>(record => (record.Id, record.Label));
            var myStructDeconstructor = DelegateWriter.Reader<MyStruct, (int, string)>(record => (record.Id, record.Label));
            // </11>
        }
        {
            // <12>
            IWriterToRef<MyClass, (int, string)> myClassDeconstructor = new MyClassDeconstructor1();
            IWriterToRef<MyStruct, (int, string)> myStructDeconstructor = new MyStructDeconstructor1();
            // </12>
        }
        {
            // <14>
            IWriterToRef<MyClass, (int, string)> myClassDeconstructor = new MyClassDeconstructor2();
            IWriterToRef<MyStruct, (int, string)> myStructDeconstructor = new MyStructDeconstructor2();
            // </14>
        }

        {
            // <16>
            RecordDeconstructorRequest myClassRequest = new RecordDeconstructorRequest(typeof(MyClass));
            RecordDeconstructorRequest myStructRequest = new RecordDeconstructorRequest(typeof(MyStruct));
            IWriterToRef<MyClass, (int, string)> myClassDeconstructor = AccessorServices.Instance.GetRequired<RecordDeconstructorRequest, IWriterToRef<MyClass, (int, string)>>(myClassRequest);
            IWriterToRef<MyStruct, (int, string)> myStructDeconstructor = AccessorServices.Instance.GetRequired<RecordDeconstructorRequest, IWriterToRef<MyStruct, (int, string)>>(myStructRequest);
            // </16>
        }

        {
            // <17>
            IRecordDescription myClassDescription = new RecordDescription().Read(typeof(MyClass)).AssignConstructors().ChooseConstruction().SetReadOnly();
            RecordDeconstructorRequest myClassRequest = new RecordDeconstructorRequest(myClassDescription);
            IWriterToRef<MyClass, (int, string)> myClassDeconstructor = AccessorServices.Instance.GetRequired<RecordDeconstructorRequest, IWriterToRef<MyClass, (int, string)>>(myClassRequest);
            // </17>
            IRecordDescription myStructDescription = new RecordDescription().Read(typeof(MyStruct)).AssignConstructors().ChooseConstruction().SetReadOnly();
            RecordDeconstructorRequest myStructRequest = new RecordDeconstructorRequest(myStructDescription);
            IWriterToRef<MyStruct, (int, string)> myStructDeconstructor = AccessorServices.Instance.GetRequired<RecordDeconstructorRequest, IWriterToRef<MyStruct, (int, string)>>(myStructRequest);
        }

        {
            // <21>
            IWriterToRef<MyClass, (int, string)> myClassDeconstructor = new MyClassDeconstructor2();
            IWriterToRef<MyStruct, (int, string)> myStructDeconstructor = new MyStructDeconstructor2();
            // </21>

            // <22>
            MyClass myClass = new MyClass(5, "Hello");
            (int, string) tuple1 = myClassDeconstructor.Read(myClass);
            MyStruct myStruct = new MyStruct(5, "Hello");
            (int, string) tuple2 = myClassDeconstructor.Read(myClass);

            // Create record box
            object box = myStruct;

            // Read tuple box
            object tupleBox = null!;
            myStructDeconstructor.TypeCast<object, object>().WriteAs<object, object>(box, ref tupleBox);
            // </22>

            // <23>
            tupleBox = myStructDeconstructor.TypeCast<object, object>().ReadAs<object, object>(box);
            // </23>
        }


        {
            // <32>
            // Create service
            IService service = Services.Create((AccessorServices.Handlers, new MyClassDeconstructorBuilder()), CachePolicies.Default);
            // Constructor request
            RecordDeconstructorRequest myClassRequest = new RecordDeconstructorRequest(typeof(MyClass));
            // Get deconstructor
            IWriterToRef<MyClass, (int, string)> myClassDeconstructor =
                service.GetRequired<RecordDeconstructorRequest, IWriterToRef<MyClass, (int, string)>>(myClassRequest);
            //
            (int, string) tuple = myClassDeconstructor.Read(new MyClass(80, "A"));
            // </32>
        }
    }

    // <00>
    public record MyClass(int Id, string Label);
    public record struct MyStruct(int Id, string Label);
    // </00>

    // <13>
    /// <summary></summary>
    public class MyClassDeconstructor1 : WriterToRef<MyClass, (int, string)>
    {
        /// <summary></summary>
        public override bool TryWrite(MyClass from, ref (int, string) to, IServiceProvider? context = null)
        {
            to.Item1 = from.Id;
            to.Item2 = from.Label;
            return true;
        }
    }

    /// <summary></summary>
    public class MyStructDeconstructor1 : WriterToRef<MyStruct, (int, string)>
    {
        /// <summary></summary>
        public override bool TryWrite(MyStruct from, ref (int, string) to, IServiceProvider? context = null)
        {
            to.Item1 = from.Id;
            to.Item2 = from.Label;
            return true;
        }
    }
    // </13>

    // <15>
    /// <summary></summary>
    public class MyClassDeconstructor2 : RecordDeconstructorBase<MyClass, (int, string)>
    {
        /// <summary></summary>
        public override bool TryWrite(MyClass from, ref (int, string) to, IServiceProvider? context = null)
        {
            to.Item1 = from.Id;
            to.Item2 = from.Label;
            return true;
        }
    }

    /// <summary></summary>
    public class MyStructDeconstructor2 : RecordDeconstructorBase<MyStruct, (int, string)>
    {
        /// <summary></summary>
        public override bool TryWrite(MyStruct from, ref (int, string) to, IServiceProvider? context = null)
        {
            to.Item1 = from.Id;
            to.Item2 = from.Label;
            return true;
        }
    }
    // </15>

    // <31>
    public class MyClassDeconstructorBuilder : IHandler<RecordDeconstructorRequest, IWriterBase>
    {
        [Order(-100)]
        public void Handle(IQuery<RecordDeconstructorRequest, IWriterBase> query)
        {
            // Already handled
            if (query.Handled()) return;

            // Place type here
            Type? recordType = null;
            //
            if (query.Request.Record is IRecordDescription recordDescription1) recordType = recordDescription1?.Type;
            //
            else if (query.Request.Record is Type type1) recordType = type1;
            //
            else return;

            // This handler only handles "MyClass"
            if (recordType == null || !recordType.Equals(typeof(MyClass))) return;
            // Assign constructor
            query.Response.SetValue(new MyClassDeconstructor2());

        }
    }
    // </31>
}