/// <inheritdoc></inheritdoc>
public IDisposable OnChange(Action <TOptions> listener)
{
var disposable = new ChangeTrackerDisposable();
foreach (var source in _sources)
{
Action <object> callback = null;
IDisposable previousSubscription = null;
callback = (s) =>
{
// The order here is important. We need to take the token and then apply our changes BEFORE
// registering. This prevents us from possible having two change updates to process concurrently.
//
// If the token changes after we take the token, then we'll process the update immediately upon
// registering the callback.
var token = source.GetChangeToken();
// Recompute the options before calling the watchers
_optionsCache = new OptionsCache <TOptions>(_setups);
listener(_optionsCache.Value);
// Remove the old callback after its been fired
var nextSubscription = token.RegisterChangeCallback(callback, s);
disposable.Disposables.Add(nextSubscription);
disposable.Disposables.Remove(previousSubscription);
previousSubscription = nextSubscription;
};
previousSubscription = source.GetChangeToken().RegisterChangeCallback(callback, state: null);
disposable.Disposables.Add(previousSubscription);
}
return(disposable);
}
/// <summary>
/// Initializes a new instance with the specified options configurations.
/// </summary>
/// <param name="setups">The configuration actions to run.</param>
public OptionsManager(IEnumerable <IConfigureOptions <TOptions> > setups)
{
_optionsCache = new OptionsCache <TOptions>(setups);
}
/// <summary>
/// Constructor.
/// </summary>
/// <param name="setups">The configuration actions to run on an options instance.</param>
/// <param name="sources">The sources used to listen for changes to the options instance.</param>
public OptionsMonitor(IEnumerable <IConfigureOptions <TOptions> > setups, IEnumerable <IOptionsChangeTokenSource <TOptions> > sources)
{
_sources = sources;
_setups = setups;
_optionsCache = new OptionsCache <TOptions>(setups);
}