internal static object TryDecorateRegistration(
Service service,
IComponentRegistration registration,
object instance,
IComponentContext context,
IEnumerable <Parameter> parameters)
{
if (service is DecoratorService ||
!(service is IServiceWithType serviceWithType) ||
registration is ExternalComponentRegistration)
{
return(instance);
}
var decoratorRegistrations = context.ComponentRegistry.DecoratorsFor(serviceWithType);
if (decoratorRegistrations.Count == 0)
{
return(instance);
}
var serviceType = serviceWithType.ServiceType;
var resolveParameters = parameters as Parameter[] ?? parameters.ToArray();
var instanceType = instance.GetType();
var decoratorContext = DecoratorContext.Create(instanceType, serviceType, instance);
var decoratorCount = decoratorRegistrations.Count;
for (var index = 0; index < decoratorCount; index++)
{
var decoratorRegistration = decoratorRegistrations[index];
var decoratorService = decoratorRegistration.Services.OfType <DecoratorService>().First();
if (!decoratorService.Condition(decoratorContext))
{
continue;
}
var serviceParameter = new TypedParameter(serviceType, instance);
var contextParameter = new TypedParameter(typeof(IDecoratorContext), decoratorContext);
var invokeParameters = new Parameter[resolveParameters.Length + 2];
for (var i = 0; i < resolveParameters.Length; i++)
{
invokeParameters[i] = resolveParameters[i];
}
invokeParameters[invokeParameters.Length - 2] = serviceParameter;
invokeParameters[invokeParameters.Length - 1] = contextParameter;
var resolveRequest = new ResolveRequest(decoratorService, decoratorRegistration, invokeParameters);
instance = context.ResolveComponent(resolveRequest);
if (index < decoratorCount - 1)
{
decoratorContext = decoratorContext.UpdateContext(instance);
}
}
return(instance);
}
internal static object TryDecorateRegistration(
IComponentRegistration registration,
object instance,
IComponentContext context,
IEnumerable <Parameter> parameters)
{
var instanceType = instance.GetType();
// Issue #965: Do not apply the decorator if the registration is for an adapter.
if (registration.IsAdapting())
{
return(instance);
}
var decoratorRegistrations = context.ComponentRegistry.DecoratorsFor(registration);
// ReSharper disable once PossibleMultipleEnumeration
if (!decoratorRegistrations.Any())
{
return(instance);
}
// ReSharper disable once PossibleMultipleEnumeration
var decorators = decoratorRegistrations
.Select(r => new
{
Registration = r,
Service = r.Services.OfType <DecoratorService>().First()
})
.ToArray();
if (decorators.Length == 0)
{
return(instance);
}
var serviceType = decorators[0].Service.ServiceType;
var resolveParameters = parameters as Parameter[] ?? parameters.ToArray();
var decoratorContext = DecoratorContext.Create(instanceType, serviceType, instance);
foreach (var decorator in decorators)
{
if (!decorator.Service.Condition(decoratorContext))
{
continue;
}
var serviceParameter = new TypedParameter(serviceType, instance);
var contextParameter = new TypedParameter(typeof(IDecoratorContext), decoratorContext);
var invokeParameters = resolveParameters.Concat(new Parameter[] { serviceParameter, contextParameter });
instance = context.ResolveComponent(decorator.Registration, invokeParameters);
decoratorContext = decoratorContext.UpdateContext(instance);
}
return(instance);
}
internal static DecoratorContext Create(Type implementationType, Type serviceType, object implementationInstance)
{
var context = new DecoratorContext
{
ImplementationType = implementationType,
ServiceType = serviceType,
AppliedDecorators = new List <object>(0),
AppliedDecoratorTypes = new List <Type>(0),
CurrentInstance = implementationInstance
};
return(context);
}
internal DecoratorContext UpdateContext(object decoratorInstance)
{
var appliedDecorators = new List <object>(AppliedDecorators.Count + 1);
appliedDecorators.AddRange(AppliedDecorators);
appliedDecorators.Add(decoratorInstance);
var appliedDecoratorTypes = new List <Type>(AppliedDecoratorTypes.Count + 1);
appliedDecoratorTypes.AddRange(AppliedDecoratorTypes);
appliedDecoratorTypes.Add(decoratorInstance.GetType());
var context = new DecoratorContext
{
ImplementationType = ImplementationType,
ServiceType = ServiceType,
AppliedDecorators = appliedDecorators,
AppliedDecoratorTypes = appliedDecoratorTypes,
CurrentInstance = decoratorInstance
};
return(context);
}
/// <inheritdoc/>
public void Execute(ResolveRequestContext context, Action <ResolveRequestContext> next)
{
// Go down the pipeline first, need that instance.
next(context);
// Don't do this if we didn't activate an instance (for example because of decorator instance sharing).
if (context.Instance is null)
{
return;
}
// Check if decoration is disabled.
if (context.Registration.Options.HasOption(RegistrationOptions.DisableDecoration))
{
return;
}
if (!(context.Operation is IDependencyTrackingResolveOperation dependencyTrackingResolveOperation))
{
// Skipping decorator middleware, since IResolveOperation is not IDependencyTrackingResolveOperation
// Which contains required functionality EnterNewDependencyDetectionBlock
return;
}
// This middleware is only ever added to IServiceWithType pipelines, so this cast will always succeed.
var swt = (IServiceWithType)context.Service;
var serviceType = swt.ServiceType;
if (context.DecoratorContext is null)
{
context.DecoratorContext = DecoratorContext.Create(context.Instance.GetType(), serviceType, context.Instance);
}
else
{
// Update the context with the previous decorator's output.
// Doing this here, rather than in the decorator middleware that resulted in the instance
// means we do not need to needlessly update the decorator context on the final decorator.
context.DecoratorContext = context.DecoratorContext.UpdateContext(context.Instance);
}
if (!_decoratorService.Condition(context.DecoratorContext))
{
return;
}
var serviceParameter = new TypedParameter(serviceType, context.DecoratorContext.CurrentInstance);
var contextParameter = new TypedParameter(typeof(IDecoratorContext), context.DecoratorContext);
Parameter[] resolveParameters;
var parameterCount = context.Parameters.Count();
if (parameterCount == 0)
{
resolveParameters = new Parameter[] { serviceParameter, contextParameter };
}
else
{
resolveParameters = new Parameter[parameterCount + 2];
var idx = 0;
foreach (var existing in context.Parameters)
{
resolveParameters[idx] = existing;
idx++;
}
resolveParameters[idx++] = serviceParameter;
resolveParameters[idx++] = contextParameter;
}
// We're going to define a service registration that does not contain any service
// pipeline additions.
// Adding a service pipeline middleware to a decorator service is not valid anyway.
var resolveRequest = new ResolveRequest(
_decoratorService,
new ServiceRegistration(ServicePipelines.DefaultServicePipeline, _decoratorRegistration),
resolveParameters,
context.Registration);
using (dependencyTrackingResolveOperation.EnterNewDependencyDetectionBlock())
{
var decoratedInstance = context.ResolveComponent(resolveRequest);
context.Instance = decoratedInstance;
}
}
