public void Dispose()
{
ReferenceCountedProviders oldRefCountedProviders = _refCountedProviders;
// This lock ensures that we cannot reduce the ref count to zero before GetReference() calls AddReference().
// Once _disposed is set, GetReference() stops reference counting.
lock (_replaceProvidersLock)
{
_disposed = true;
}
// Never dispose ReferenceCountedProviders with a lock because this may call into user code.
oldRefCountedProviders.Dispose();
}
public ReferenceCountedProviders GetReference()
{
// Lock to ensure oldRefCountedProviders.Dispose() in ReplaceProviders() or Dispose() doesn't decrement ref count to zero
// before calling _refCountedProviders.AddReference().
lock (_replaceProvidersLock)
{
if (_disposed)
{
// Return a non-reference-counting ReferenceCountedProviders instance now that the ConfigurationManager is disposed.
// We could preemptively throw an ODE instead, but this might break existing apps that were previously able to
// continue to read configuration after disposing an ConfigurationManager.
return(ReferenceCountedProviders.CreateDisposed(_refCountedProviders.NonReferenceCountedProviders));
}
_refCountedProviders.AddReference();
return(_refCountedProviders);
}
}
// Providers should never be concurrently modified. Reading during modification is allowed.
public void ReplaceProviders(List <IConfigurationProvider> providers)
{
ReferenceCountedProviders oldRefCountedProviders = _refCountedProviders;
lock (_replaceProvidersLock)
{
if (_disposed)
{
throw new ObjectDisposedException(nameof(ConfigurationManager));
}
_refCountedProviders = ReferenceCountedProviders.Create(providers);
}
// Decrement the reference count to the old providers. If they are being concurrently read from
// the actual disposal of the old providers will be delayed until the final reference is released.
// Never dispose ReferenceCountedProviders with a lock because this may call into user code.
oldRefCountedProviders.Dispose();
}
