/// <summary>
/// Tries to match the selector with a control.
/// </summary>
/// <param name="control">The control.</param>
/// <param name="subscribe">
/// Whether the match should subscribe to changes in order to track the match over time,
/// or simply return an immediate result.
/// </param>
/// <returns>A <see cref="SelectorMatch"/>.</returns>
public SelectorMatch Match(IStyleable control, bool subscribe = true)
{
List <IObservable <bool> > inputs = new List <IObservable <bool> >();
Selector selector = this;
while (selector != null)
{
if (selector.InTemplate && control.TemplatedParent == null)
{
return(SelectorMatch.False);
}
var match = selector.Evaluate(control, subscribe);
if (match.ImmediateResult == false)
{
return(match);
}
else if (match.ObservableResult != null)
{
inputs.Add(match.ObservableResult);
}
selector = selector.MovePrevious();
}
if (inputs.Count > 0)
{
return(new SelectorMatch(StyleActivator.And(inputs)));
}
else
{
return(SelectorMatch.True);
}
}
private static SelectorMatchResult Match(
IStyleable control,
Selector selector,
IStyle?parent,
bool subscribe,
ref AndActivatorBuilder activators,
ref Selector?combinator)
{
var previous = selector.MovePrevious();
// Selectors are stored from right-to-left, so we recurse into the selector in order to
// reverse this order, because the type selector will be on the left and is our best
// opportunity to exit early.
if (previous != null && !previous.IsCombinator)
{
var previousMatch = Match(control, previous, parent, subscribe, ref activators, ref combinator);
if (previousMatch < SelectorMatchResult.Sometimes)
{
return(previousMatch);
}
}
// Match this selector.
var match = selector.Evaluate(control, parent, subscribe);
if (!match.IsMatch)
{
combinator = null;
return(match.Result);
}
else if (match.Activator is object)
{
activators.Add(match.Activator !);
}
if (previous?.IsCombinator == true)
{
combinator = previous;
}
return(match.Result);
}