Expression IRegistry.GetDecoratorExpressionOrDefault(Request request)
{
// Decorators for non service types are not supported.
if (request.FactoryType != FactoryType.Service)
return null;
// We are already resolving decorator for the service, so stop now.
var parent = request.GetNonWrapperParentOrDefault();
if (parent != null && parent.DecoratedFactoryID == request.FactoryID)
return null;
var serviceType = request.ServiceType;
var decoratorFuncType = typeof(Func<,>).MakeGenericType(serviceType, serviceType);
LambdaExpression resultFuncDecorator = null;
var funcDecorators = _decorators.GetValueOrDefault(decoratorFuncType);
if (funcDecorators != null)
{
var decoratorRequest = request.MakeDecorated();
for (var i = 0; i < funcDecorators.Length; i++)
{
var decorator = funcDecorators[i].Factory;
if (((DecoratorSetup)decorator.Setup).IsApplicable(request))
{
var newDecorator = decorator.GetExpression(decoratorRequest, this);
if (resultFuncDecorator == null)
{
var decorated = Expression.Parameter(serviceType, "decorated");
resultFuncDecorator = Expression.Lambda(Expression.Invoke(newDecorator, decorated), decorated);
}
else
{
var decorateDecorator = Expression.Invoke(newDecorator, resultFuncDecorator.Body);
resultFuncDecorator = Expression.Lambda(decorateDecorator, resultFuncDecorator.Parameters[0]);
}
}
}
}
IEnumerable<DecoratorsEntry> decorators = _decorators.GetValueOrDefault(serviceType);
var openGenericDecoratorIndex = decorators == null ? 0 : ((DecoratorsEntry[])decorators).Length;
if (request.OpenGenericServiceType != null)
{
var openGenericDecorators = _decorators.GetValueOrDefault(request.OpenGenericServiceType);
if (openGenericDecorators != null)
decorators = decorators == null ? openGenericDecorators : decorators.Concat(openGenericDecorators);
}
Expression resultDecorator = resultFuncDecorator;
if (decorators != null)
{
var decoratorRequest = request.MakeDecorated();
var decoratorIndex = 0;
var enumerator = decorators.GetEnumerator();
while (enumerator.MoveNext())
{
var decorator = enumerator.Current.ThrowIfNull();
var factory = decorator.Factory;
if (((DecoratorSetup)factory.Setup).IsApplicable(request))
{
// Cache closed generic registration produced by open-generic decorator.
if (decoratorIndex++ >= openGenericDecoratorIndex)
factory = Register(factory.GetFactoryPerRequestOrDefault(request, this), serviceType, null);
if (decorator.CachedExpression == null)
{
IList<Type> unusedFunArgs;
var funcExpr = factory
.GetFuncWithArgsOrDefault(decoratorFuncType, decoratorRequest, this, out unusedFunArgs)
.ThrowIfNull(Error.DECORATOR_FACTORY_SHOULD_SUPPORT_FUNC_RESOLUTION, decoratorFuncType);
decorator.CachedExpression = unusedFunArgs != null ? funcExpr.Body : funcExpr;
}
if (resultDecorator == null || !(decorator.CachedExpression is LambdaExpression))
resultDecorator = decorator.CachedExpression;
else
{
if (!(resultDecorator is LambdaExpression))
resultDecorator = Expression.Invoke(decorator.CachedExpression, resultDecorator);
else
{
var prevDecorators = ((LambdaExpression)resultDecorator);
var decorateDecorator = Expression.Invoke(decorator.CachedExpression, prevDecorators.Body);
resultDecorator = Expression.Lambda(decorateDecorator, prevDecorators.Parameters[0]);
}
}
}
}
}
return resultDecorator;
}
