} // can only be instantaited by self
public static IDataProtector GetDataProtector(ref DataProtectorHelper helperRef, IDataProtectionProvider protectionProvider, IFactorySupportFunctions supportFunctions)
{
// First, make sure that only one thread ever initializes the helper instance.
var helper = Volatile.Read(ref helperRef);
if (helper == null)
{
var newHelper = new DataProtectorHelper();
helper = Interlocked.CompareExchange(ref helperRef, newHelper, null) ?? newHelper;
}
// Has the protector already been created?
var protector = Volatile.Read(ref helper._dataProtector);
if (protector == null)
{
// Since the helper is accessed by reference, all threads should agree on the one true helper
// instance, so this lock is global given a particular reference. This is an implementation
// of the double-check lock pattern.
lock (helper)
{
protector = Volatile.Read(ref helper._dataProtector);
if (protector == null)
{
protector = supportFunctions.CreateDataProtector(protectionProvider);
Volatile.Write(ref helper._dataProtector, protector);
}
}
}
// And we're done!
Debug.Assert(protector != null);
return(protector);
}
private IDataProtector GetCachedDataProtector()
{
var dataProtectionProvider = DataProtectionProviderHelper.GetDataProtectionProvider(ref _staticHelper, this);
return(DataProtectorHelper.GetDataProtector(ref _helper, dataProtectionProvider, this));
}