private static SelectorMatch MatchUntilCombinator(
IStyleable control,
Selector start,
bool subscribe,
out Selector?combinator)
{
combinator = null;
var activators = new AndActivatorBuilder();
var result = Match(control, start, subscribe, ref activators, ref combinator);
return(result == SelectorMatchResult.Sometimes ?
new SelectorMatch(activators.Get()) :
new SelectorMatch(result));
}
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);
}
