public object Resolve(ContainerMember containerMember, Action<object, ContainerMember> afterObjectCreate)
{
if (containerMember.ObjectLifetimeManager.ObjectFactory == null)
{
containerMember.ObjectLifetimeManager.ObjectFactory = () => CreateInstanceFunction(containerMember, afterObjectCreate);
}
return containerMember.ObjectLifetimeManager.GetInstance();
}
//http://stackoverflow.com/questions/8219343/reflection-emit-create-object-with-parameters
//http://stackoverflow.com/questions/13478933/reflection-emit-to-create-class-instance
private static Func<object[], object> CreateObjectFunction(ContainerMember containerMember)
{
var ctor = containerMember.Constructor;
//this method return a function that provide fast creation of a new instastance for given constructorInfo
var dm = new DynamicMethod($"Create_{ctor.DeclaringType?.FullName.Replace('.', '_')}", typeof(object), new[] { typeof(object[]) }, true); //we create a dynamic method
var ilgen = dm.GetILGenerator(); //we get the IL Generator from dynamic method
var parameters = ctor.GetParameters(); //we get constructor parameters
for (var i = 0; i < parameters.Length; i++)
{
ilgen.Emit(OpCodes.Ldarg_0); //first we put a correct parameter onto the stack
EmitHelper.EmitIntOntoStack(ilgen, i); //next we put a correct index onto the stack again
ilgen.Emit(OpCodes.Ldelem_Ref); //then we take an index and a parameter from the stack and we put the parameter in an array in a correct index
var paramType = parameters[i].ParameterType;
ilgen.Emit(paramType.IsValueType ? OpCodes.Unbox_Any : OpCodes.Castclass, paramType); //finally we cast the parameter to the correct type
}
ilgen.Emit(OpCodes.Newobj, ctor); //at the end we create a new object that takes an array of parameters as constructor parameters
ilgen.Emit(OpCodes.Ret); //we return created object
return (Func<object[], object>)dm.CreateDelegate(typeof(Func<object[], object>));
}
private object CreateInstanceFunction(ContainerMember containerMember, Action<object, ContainerMember> afterObjectCreate)
{
var ctorParameters = containerMember.Parameters;
var ctorParametersCount = ctorParameters.Count;
var parameters = new object[ctorParametersCount];
for (var i = 0; i < ctorParametersCount; i++) //we create as array with the parameters of the constructor and we fill it
{
var parameterContainerMember = _registeredTypesCache.GetValue(ctorParameters[i].ParameterType);
parameters[i] = Resolve(parameterContainerMember, afterObjectCreate);
}
if (!_createPartialEmitFunctionForConstructorCache.ContainsKey(containerMember.ReturnType)) //if we do not have a create object function in the cache, we create it
{
var factoryMethod = CreateObjectFunction(containerMember);
_createPartialEmitFunctionForConstructorCache.Add(containerMember.ReturnType, factoryMethod);
}
var obj = _createPartialEmitFunctionForConstructorCache[containerMember.ReturnType](parameters);
afterObjectCreate(obj, containerMember); //when we have a new instance of the type, we have to resolve the properties and the methods also
return obj;
}
