Extremely Fast Dependency Injection Library.
Switch branches/tags
Nothing to show
Clone or download
Latest commit 10ed043 Dec 21, 2017

ReadMe.md

MicroResolver

Extremely Fast Dependency Injection Library.

Features

MicroResolver is desgined for performance. I've released two fastest serializers ZeroFormatter and MessagePack for C#, this library is using there dynamic il code generation technique.

MicroResolver achived fastest at some tests in IoCPerformance benchmark - Singleton(Multithread), Combined(Multithread), Property(Singlethread, Multithread) and other result also top level. This benchmark is nongeneric test(use (object Resove(Type type)), MicroResolver is focused to optimize for generic method(T Resolve<T>()), if using it, faster than other libraries.

Support Features - Consturctor Injection, Field Injection, Property Injection, Method Injection, Collection resolver and Three lifetime support(Singleton, Transient and Scoped).

Quick Start

Install from NuGet(for .NET Framework 4.6, .NET Standard 1.4)

// Create a new container
var resolver = ObjectResolver.Create();

// Register interface->type map, default is transient(instantiate every request)
resolver.Register<IUserRepository, SqlUserRepository>();

// You can configure lifestyle - Transient, Singleton or Scoped
resolver.Register<ILogger, MailLogger>(Lifestyle.Singleton);

// Compile and Verify container(this is required step)
resolver.Compile();

// Get instance from container
var userRepository = resolver.Resolve<IUserRepository>();
var logger = resolver.Resolve<ILogger>();

Notice: MicroResolver requests call Compile before use container.

InjectionAttribute and Resolve Collection

MicroResolver can resolve all public and private properties, fields, constructor and methods. Inject target have to mark [Inject] attribute.

public class MyType : IMyType
{
    // field injection

    [Inject]
    public IInjectTarget PublicField;

    [Inject]
    IInjectTarget PrivateField;

    // property injection

    [Inject]
    public IInjectTarget PublicProperty { get; set; }

    [Inject]
    IInjectTarget PrivateProperty { get; set; }

    // constructor injection
    // if not marked [Inject], the constructor with the most parameters is used.
    [Inject]
    public MyType(IInjectTarget x, IInjectTarget y, IInjectTarget z)
    {

    }

    // method injection

    [Inject]
    public void Initialize1()
    {
    }

    [Inject]
    public void Initialize2()
    {
    }
}

// and resolve it
var v = resolver.Resolve<IMyType>();

Inject order is Constructor -> Field -> Property -> Method.

If register many types per type, you can use RegisterCollection and Resolve<IEnumerable<T>>.

// Register type -> many types
resolver.RegisterCollection<IMyType>(typeof(T1), typeof(T2), typeof(T3));

resolver.Compile();

// can resolve by IEnumerbale<T> or T[] or IReadOnlyList<T>.
resolver.Resolve<IEnumerable<IMyType>>();
resolver.Resolve<IMyType[]>();
resolver.Resolve<IReadOnlyList<IMyType>>();

// can resolve other type's inject target.
public class AnotherType
{
    public AnotherType(IMyType[] targets)
    {
    }
}

Scoped

Lifetime.Scoped is usually the same as Transient but within BeginScope it behaves like a singleton in the scope.

// sample type of check scope
public class MyClass : IMyType, IDisposable
{
    public MyClass()
    {
        Console.WriteLine("Created");
    }

    public void Dispose()
    {
        Console.WriteLine("Disposed");
    }
}

// -----------

var resolver = ObjectResolver.Create();
resolver.Register<IMyType, MyClass>(Lifestyle.Scoped);
resolver.Compile();

using (var coResolver = resolver.BeginScope(ScopeProvider.Standard))
{
    var i1 = coResolver.Resolve<IMyType>(); // "Created"
    var i2 = coResolver.Resolve<IMyType>();

    Console.WriteLine(Object.ReferenceEquals(i1, i2)); // "True" -> same instance

    // if scope end and instantiated types is IDisposable, called Dispose.
} // "Disposed"

ScopeProvider has three option in default. ScopeProvider.Standard, ScopeProvider.ThreadLocal and ScopeProvider.AsyncLocal. If needs custom scope, you can create own ScopeProvider.

public class MyScopeProvider : ScopeProvider
{
    public override void Initialize(IObjectResolver resolver)
    {
        // when called from BeginScope().
    }

    protected override object GetValueFromScoped(Type type, out bool isFirstCreated)
    {
        // called per Resolve<T>.
    }
}

Performance Technique - Dynamic IL Inlining

Everyone creates dynamic code generation for optimize performance. But if target is complex type?

// sample of complex dependency type
public class ForPropertyInjection : IForPropertyInjection
{
    [Inject]
    public void OnCreate()
    {
    }
}

public class ForConstructorInjection : IForConsturctorInjection
{
    [Inject]
    public IForFieldInjection MyField;
}

public class ComplexType : IComplexType
{
    [Inject]
    public IForPropertyInjection MyProperty { get; set; }

    public ComplexType(IForConsturctorInjection instance1)
    {

    }

    [Inject]
    public void Initialize()
    {
    }
}

// for example, how to resolve ComplexType?
var v = resolver.Resolve<IComplexType>();

The following way is not slow, but it is not fastest.

// This is `slow` example of complex type resolve
static IComplexType ResolveComplexType(IObjectResolver resolver)
{
    var a = resolver.Resolve<IForConsturctorInjection>();
    var b = resolver.Resolve<IForPropertyInjection>();

    var result = new ComplexType(a);
    result.MyProperty = b;
    result.Initialize();

    return result;
}

MicroResolve choose inlining code generation, all dependencies are analyzed and inlined at compile time.

// This is actual code generation of MicroResolver, all dependency is inlined at il code generation
static IComplexType ResolveComposite()
{
    var a = new ForConstructorInjection();
    a.MyField = new ForFieldInjection();
    var b = new ForPropertyInjection();
    b.OnCreate();

    var result = new ComplexType(a);
    result.MyProperty = b;
    result.Initialize();

    return result;
}

Performance Technique - Generic Type Caching per resolver

The generated code is cached. And how to retrieve it? ConcurrentDictionary? Dictionary? They are slow. MicroResolve choose generic type caching.

This is ObjectResolver signature.

public abstract class ObjectResolver
{
    public abstract T Resolve<T>();
}

If called ObjectResolver.Create, generate dynamic inherited type.

public class ObjectResolver_Generated : ObjectResolver
{
    public override T Resolve<T>()
    {
        // too simple, of course simple is fastest.
        return Cache<T>.factory();
    }

    Cache<T>
    {
        // generated Func<T> code is see 'Dynamic IL Inlining' section.
        public Func<T> factory;
    }
}

The code path is too short, it means no overhead.

But generated container can not remove. This is a design constraint.

Performance Technique - Fast NonGeneric lookup table

Type Caching is require to use generics method. But often framework requests nongeneric type.

// fastest
resolver.Resolve<T>();

// slower but framework requests this method
(T)resolver.Resolve(type);

MicroResolver use fast type lookup by own fixed hashtable.

// buckets item
struct HashTuple
{
    public Type type;
    public Func<object> factory;
}

// simplest hash table(fixed-array chaining hashtable)
private HashTuple[][] table;

// register - Func<T> -> Func<object> by delegate covariance
table[hash][index] = new Func<object>(Cache<T>.factory);

// simplest == fastest lookup
public object Resolve(Type type)
{
    var hashCode = type.GetHashCode();
    var buckets = table[hashCode & tableMaskIndex]; // table size is power of 2, fast lookup

    // .Length for loop can remove array bounds check
    for (int i = 0; i < buckets.Length; i++)
    {
        if (buckets[i].type == type)
        {
            return buckets[i].factory();
        }
    }

    throw new MicroResolverException("Type was not dound, Type: " + type.FullName);
}

non-generic lookup is slower than generic but still fast.

Author Info

Yoshifumi Kawai(a.k.a. neuecc) is a software developer in Japan.
He is the Director/CTO at Grani, Inc.
Grani is a mobile game developer company in Japan and well known for using C#.
He is awarding Microsoft MVP for Visual C# since 2011.
He is known as the creator of UniRx(Reactive Extensions for Unity)

Blog: https://medium.com/@neuecc (English)
Blog: http://neue.cc/ (Japanese)
Twitter: https://twitter.com/neuecc (Japanese)

License

This library is under the MIT License.