generic-async-composition-roots-with-constraints.md

Generic async composition roots with constraints

Important

`Resolve' methods cannot be used to resolve generic composition roots.

interface IDependency<T>
    where T : IDisposable;

class Dependency<T> : IDependency<T>
    where T : IDisposable;

interface IService<T, TStruct>
    where T : IDisposable
    where TStruct : struct;

class Service<T, TStruct>(IDependency<T> dependency) : IService<T, TStruct>
    where T : IDisposable
    where TStruct : struct;

class OtherService<T>(IDependency<T> dependency) : IService<T, bool>
    where T : IDisposable;

DI.Setup(nameof(Composition))
    // This hint indicates to not generate methods such as Resolve
    .Hint(Hint.Resolve, "Off")
    .Bind().To<Dependency<TTDisposable>>()
    .Bind().To<Service<TTDisposable, TTS>>()
    // Creates OtherService manually,
    // just for the sake of example
    .Bind("Other").To(ctx =>
    {
        ctx.Inject(out IDependency<TTDisposable> dependency);
        return new OtherService<TTDisposable>(dependency);
    })

    // Specifies to use CancellationToken from the argument
    // when resolving a composition root
    .RootArg<CancellationToken>("cancellationToken")

    // Specifies to create a regular public method
    // to get a composition root of type Task<Service<T, TStruct>>
    // with the name "GetMyRootAsync"
    .Root<Task<IService<TTDisposable, TTS>>>("GetMyRootAsync")

    // Specifies to create a regular public method
    // to get a composition root of type Task<OtherService<T>>
    // with the name "GetOtherServiceAsync"
    // using the "Other" tag
    .Root<Task<IService<TTDisposable, bool>>>("GetOtherServiceAsync", "Other");

var composition = new Composition();

// Resolves composition roots asynchronously
var service = await composition.GetMyRootAsync<Stream, double>(CancellationToken.None);
var someOtherService = await composition.GetOtherServiceAsync<BinaryReader>(CancellationToken.None);

Important

The method Inject()cannot be used outside of the binding setup.

The following partial class will be generated:

partial class Composition
{
  private readonly Composition _root;

  [OrdinalAttribute(10)]
  public Composition()
  {
    _root = this;
  }

  internal Composition(Composition parentScope)
  {
    _root = (parentScope ?? throw new ArgumentNullException(nameof(parentScope)))._root;
  }

  [MethodImpl(MethodImplOptions.AggressiveInlining)]
  public Task<IService<T, bool>> GetOtherServiceAsync<T>(CancellationToken cancellationToken)
    where T: IDisposable
  {
    TaskScheduler transientTaskScheduler5 = TaskScheduler.Default;
    TaskContinuationOptions transientTaskContinuationOptions4 = TaskContinuationOptions.None;
    TaskCreationOptions transientTaskCreationOptions3 = TaskCreationOptions.None;
    TaskFactory<IService<T, bool>> perBlockTaskFactory2;
    CancellationToken localCancellationToken46 = cancellationToken;
    TaskCreationOptions localTaskCreationOptions47 = transientTaskCreationOptions3;
    TaskContinuationOptions localTaskContinuationOptions48 = transientTaskContinuationOptions4;
    TaskScheduler localTaskScheduler49 = transientTaskScheduler5;
    perBlockTaskFactory2 = new TaskFactory<IService<T, bool>>(localCancellationToken46, localTaskCreationOptions47, localTaskContinuationOptions48, localTaskScheduler49);
    Func<IService<T, bool>> perBlockFunc1 = new Func<IService<T, bool>>([MethodImpl(MethodImplOptions.AggressiveInlining)] () =>
    {
      OtherService<T> transientOtherService6;
      IDependency<T> localDependency51 = new Dependency<T>();
      transientOtherService6 = new OtherService<T>(localDependency51);
      IService<T, bool> localValue50 = transientOtherService6;
      return localValue50;
    });
    Task<IService<T, bool>> transientTask0;
    // Injects an instance factory
    Func<IService<T, bool>> localFactory52 = perBlockFunc1;
    // Injects a task factory creating and scheduling task objects
    TaskFactory<IService<T, bool>> localTaskFactory53 = perBlockTaskFactory2;
    // Creates and starts a task using the instance factory
    transientTask0 = localTaskFactory53.StartNew(localFactory52);
    return transientTask0;
  }

  [MethodImpl(MethodImplOptions.AggressiveInlining)]
  public Task<IService<T, T1>> GetMyRootAsync<T, T1>(CancellationToken cancellationToken)
    where T: IDisposable
    where T1: struct
  {
    TaskScheduler transientTaskScheduler5 = TaskScheduler.Default;
    TaskContinuationOptions transientTaskContinuationOptions4 = TaskContinuationOptions.None;
    TaskCreationOptions transientTaskCreationOptions3 = TaskCreationOptions.None;
    TaskFactory<IService<T, T1>> perBlockTaskFactory2;
    CancellationToken localCancellationToken54 = cancellationToken;
    TaskCreationOptions localTaskCreationOptions55 = transientTaskCreationOptions3;
    TaskContinuationOptions localTaskContinuationOptions56 = transientTaskContinuationOptions4;
    TaskScheduler localTaskScheduler57 = transientTaskScheduler5;
    perBlockTaskFactory2 = new TaskFactory<IService<T, T1>>(localCancellationToken54, localTaskCreationOptions55, localTaskContinuationOptions56, localTaskScheduler57);
    Func<IService<T, T1>> perBlockFunc1 = new Func<IService<T, T1>>([MethodImpl(MethodImplOptions.AggressiveInlining)] () =>
    {
      IService<T, T1> localValue58 = new Service<T, T1>(new Dependency<T>());
      return localValue58;
    });
    Task<IService<T, T1>> transientTask0;
    // Injects an instance factory
    Func<IService<T, T1>> localFactory59 = perBlockFunc1;
    // Injects a task factory creating and scheduling task objects
    TaskFactory<IService<T, T1>> localTaskFactory60 = perBlockTaskFactory2;
    // Creates and starts a task using the instance factory
    transientTask0 = localTaskFactory60.StartNew(localFactory59);
    return transientTask0;
  }
}

Class diagram:

classDiagram
	class Composition {
		<<partial>>
		+TaskᐸIServiceᐸTˏT1ᐳᐳ GetMyRootAsyncᐸTˏT1ᐳ(System.Threading.CancellationToken cancellationToken)
		+TaskᐸIServiceᐸTˏBooleanᐳᐳ GetOtherServiceAsyncᐸTᐳ(System.Threading.CancellationToken cancellationToken)
	}
	class TaskScheduler
	class TaskCreationOptions
	class TaskContinuationOptions
	class TaskFactory
	class CancellationToken
	class FuncᐸIServiceᐸTˏBooleanᐳᐳ
	class TaskFactoryᐸIServiceᐸTˏBooleanᐳᐳ
	class FuncᐸIServiceᐸTˏT1ᐳᐳ
	class TaskFactoryᐸIServiceᐸTˏT1ᐳᐳ
	OtherServiceᐸTᐳ --|> IServiceᐸTˏBooleanᐳ : "Other" 
	class OtherServiceᐸTᐳ
	ServiceᐸTˏT1ᐳ --|> IServiceᐸTˏT1ᐳ
	class ServiceᐸTˏT1ᐳ {
		+Service(IDependencyᐸTᐳ dependency)
	}
	DependencyᐸTᐳ --|> IDependencyᐸTᐳ
	class DependencyᐸTᐳ {
		+Dependency()
	}
	class IServiceᐸTˏBooleanᐳ {
		<<interface>>
	}
	class IServiceᐸTˏT1ᐳ {
		<<interface>>
	}
	class IDependencyᐸTᐳ {
		<<interface>>
	}
	Composition ..> TaskᐸIServiceᐸTˏBooleanᐳᐳ : TaskᐸIServiceᐸTˏBooleanᐳᐳ GetOtherServiceAsyncᐸTᐳ(System.Threading.CancellationToken cancellationToken)
	Composition ..> TaskᐸIServiceᐸTˏT1ᐳᐳ : TaskᐸIServiceᐸTˏT1ᐳᐳ GetMyRootAsyncᐸTˏT1ᐳ(System.Threading.CancellationToken cancellationToken)
	TaskFactory o-- CancellationToken : Argument "cancellationToken"
	TaskFactory *--  TaskCreationOptions : TaskCreationOptions
	TaskFactory *--  TaskContinuationOptions : TaskContinuationOptions
	TaskFactory *--  TaskScheduler : TaskScheduler
	TaskᐸIServiceᐸTˏBooleanᐳᐳ o-- "PerBlock" FuncᐸIServiceᐸTˏBooleanᐳᐳ : "Other"  FuncᐸIServiceᐸTˏBooleanᐳᐳ
	TaskᐸIServiceᐸTˏBooleanᐳᐳ o-- "PerBlock" TaskFactoryᐸIServiceᐸTˏBooleanᐳᐳ : TaskFactoryᐸIServiceᐸTˏBooleanᐳᐳ
	TaskᐸIServiceᐸTˏT1ᐳᐳ o-- "PerBlock" FuncᐸIServiceᐸTˏT1ᐳᐳ : FuncᐸIServiceᐸTˏT1ᐳᐳ
	TaskᐸIServiceᐸTˏT1ᐳᐳ o-- "PerBlock" TaskFactoryᐸIServiceᐸTˏT1ᐳᐳ : TaskFactoryᐸIServiceᐸTˏT1ᐳᐳ
	FuncᐸIServiceᐸTˏBooleanᐳᐳ *--  OtherServiceᐸTᐳ : "Other"  IServiceᐸTˏBooleanᐳ
	TaskFactoryᐸIServiceᐸTˏBooleanᐳᐳ o-- CancellationToken : Argument "cancellationToken"
	TaskFactoryᐸIServiceᐸTˏBooleanᐳᐳ *--  TaskCreationOptions : TaskCreationOptions
	TaskFactoryᐸIServiceᐸTˏBooleanᐳᐳ *--  TaskContinuationOptions : TaskContinuationOptions
	TaskFactoryᐸIServiceᐸTˏBooleanᐳᐳ *--  TaskScheduler : TaskScheduler
	FuncᐸIServiceᐸTˏT1ᐳᐳ *--  ServiceᐸTˏT1ᐳ : IServiceᐸTˏT1ᐳ
	TaskFactoryᐸIServiceᐸTˏT1ᐳᐳ o-- CancellationToken : Argument "cancellationToken"
	TaskFactoryᐸIServiceᐸTˏT1ᐳᐳ *--  TaskCreationOptions : TaskCreationOptions
	TaskFactoryᐸIServiceᐸTˏT1ᐳᐳ *--  TaskContinuationOptions : TaskContinuationOptions
	TaskFactoryᐸIServiceᐸTˏT1ᐳᐳ *--  TaskScheduler : TaskScheduler
	OtherServiceᐸTᐳ *--  DependencyᐸTᐳ : IDependencyᐸTᐳ
	ServiceᐸTˏT1ᐳ *--  DependencyᐸTᐳ : IDependencyᐸTᐳ

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