private Expression BuildDecoratorExpression(IDecoratableEnumerable collection,
out IEnumerable <KnownRelationship> foundRelationships)
{
foundRelationships = Enumerable.Empty <KnownRelationship>();
// When we're dealing with a Singleton decorator, we must cache the list, because other theads
// could create another 'singleton' instance of this decorator. But since this list is at this
// point currently just a list of Expressions (returned as constant), we can always cache this
// list, even if the decorator is transient. This cache is an instance list, since it is specific
// to the current decorator registration.
lock (this.decoratableEnumerablesCache)
{
IDecoratableEnumerable decoratedCollection;
if (!this.decoratableEnumerablesCache.TryGetValue(this.registeredServiceType,
out decoratedCollection))
{
decoratedCollection =
this.BuildDecoratableEnumerable(collection, out foundRelationships);
this.decoratableEnumerablesCache[this.registeredServiceType] = decoratedCollection;
}
return(Expression.Constant(decoratedCollection));
}
}
private IDecoratableEnumerable BuildDecoratableEnumerable(IDecoratableEnumerable originalDecoratables,
out IEnumerable <KnownRelationship> foundRelationships)
{
var contexts = (
from context in originalDecoratables.GetDecoratorPredicateContexts()
let predicateIsSatisfied = this.SatisfiesPredicate(context)
select new
{
IsDecorated = predicateIsSatisfied,
OriginalContext = context,
Context = predicateIsSatisfied ? this.DecorateContext(context) : context,
})
.ToArray();
foundRelationships = (
from context in contexts
where context.IsDecorated
let dependency = context.OriginalContext.Registration
let decoratorRegistration = context.Context.Registration.Registration
from relationship in this.GetKnownDecoratorRelationships(decoratorRegistration,
this.decoratorConstructor, this.registeredServiceType, dependency)
select relationship)
.ToArray();
var allContexts = contexts.Select(c => c.Context).ToArray();
return(DecoratorHelpers.CreateDecoratedEnumerable(this.registeredServiceType, this.Container,
allContexts));
}