/// <summary>
/// Find the exported services in the extended <paramref name="reader"/>.
/// </summary>
/// <param name="reader"> The extended <see cref="MetadataReader"/>. </param>
/// <returns> The found collection of exported services. </returns>
public static IEnumerable <ServiceDescriptor> FindExportedServices(this MetadataReader reader)
{
var foundServices = new List <ServiceDescriptor>();
foreach (var service in reader.GetExportedServices())
{
var lifetime = Lifetime.Transient;
TypeDescriptor?contractFilter = null;
foreach (var value in service.ExportAttribute.FixedArguments)
{
if (value.Type.FullName == typeof(Lifetime).FullName)
{
lifetime = (Lifetime)(value.Value ?? Lifetime.Transient);
}
else if (value.Type.FullName == typeof(Type).FullName)
{
contractFilter = (TypeDescriptor?)value.Value;
}
}
var serviceId = (string?)null;
foreach (var argument in service.ExportAttribute.NamedArguments)
{
if (argument.Name == "ServiceId" && argument.Value is string value)
{
serviceId = value;
}
}
var implementation = reader.ToTypeDescriptor(service.TypeDefinition);
var dependencies = reader.GetConstructorDependencies(service.TypeDefinition);
if (contractFilter.HasValue)
{
foundServices.Add(new ServiceDescriptor(
contractFilter.Value,
implementation,
dependencies,
lifetime,
serviceId));
}
else
{
var implementedInterfaces = reader.GetImplementedInterfaces(service.TypeDefinition);
if (implementedInterfaces.Any())
{
foreach (var @interface in implementedInterfaces)
{
foundServices.Add(new ServiceDescriptor(
@interface,
implementation,
dependencies,
lifetime,
serviceId));
}
}
else
{
foundServices.Add(new ServiceDescriptor(
implementation,
dependencies,
lifetime,
serviceId));
}
}
}
return(foundServices);
}