public void AddInstance <TService>(TService instance)
{
var instanceDelivery = new InstanceDelivery(LifetimeStatus.Singleton, instance?.GetType()); // don't check the constructor
singletons.AddOrUpdate(instanceDelivery, instance, (key, existing) => instance);
Add(typeof(TService), instanceDelivery);
}
private void Add(Type type, InstanceDelivery instanceDelivery) =>
types.AddOrUpdate(type,
t => new[] { instanceDelivery }.ToImmutableList(),
(t, l) =>
{
var b = l.ToBuilder();
b.Add(instanceDelivery);
return(b.ToImmutable());
});
private object Resolve(Stack <Type> creating, InstanceDelivery instanceDelivery)
{
switch (instanceDelivery.Lifetime)
{
case LifetimeStatus.Singleton:
return(singletons.GetOrAdd(instanceDelivery, d => Create(creating, d)));
case LifetimeStatus.Transient:
return(Create(creating, instanceDelivery));
default:
throw new ArgumentOutOfRangeException();
}
}
private object Create(Stack <Type> creating, InstanceDelivery instanceDelivery)
{
if (creating.Contains(instanceDelivery.Type))
{
var allTypes = new[] { instanceDelivery.Type }.Concat(creating).ToArray();
throw new ResolutionException("Circular reference when creating the following types:" +
$"{Environment.NewLine}{string.Join(Environment.NewLine, allTypes.Select(t => t.FullName))}");
}
creating.Push(instanceDelivery.Type);
try
{
var constructor = constructors.GetOrAdd(instanceDelivery.Type, GetConstructor); //should always already be in.
var parameterValues = new List <object>();
foreach (var parameterInfo in constructor.GetParameters())
{
var parameterValue = Resolve(creating, parameterInfo.ParameterType);
parameterValues.Add(parameterValue);
}
try
{
var resolution = constructor.Invoke(parameterValues.ToArray());
return(resolution);
}
catch (Exception e)
{
var allTypes = creating.ToArray(); //already got the type we're trying to create in the stack
throw new ResolutionException("Resolution failed when creating the following types:" +
$"{Environment.NewLine}{string.Join(Environment.NewLine, allTypes.Select(t => t.FullName))}",
e);
}
}
finally
{
creating.Pop();
}
}