public virtual MatchResultInfo Match(VisualElement element, ref RuleMatcher matcher, int selectorIndex)
{
if (element == null)
{
return(default(MatchResultInfo));
}
bool match = true;
StyleSelector selector = matcher.complexSelector.selectors[selectorIndex];
int count = selector.parts.Length;
int triggerPseudoStateMask = 0;
int dependencyPseudoMask = 0;
bool failedOnlyOnPseudoStates = true;
for (int i = 0; i < count; i++)
{
bool isPartMatch = MatchSelectorPart(element, selector, selector.parts[i]);
if (!isPartMatch)
{
if (selector.parts[i].type == StyleSelectorType.PseudoClass)
{
// if the element had those flags defined, it would match this selector
triggerPseudoStateMask |= selector.pseudoStateMask;
// if the element didnt' have those flags, it would match this selector
dependencyPseudoMask |= selector.negatedPseudoStateMask;
}
else
{
failedOnlyOnPseudoStates = false;
}
}
else
{
if (selector.parts[i].type == StyleSelectorType.PseudoClass)
{
// the element matches this selector because it has those flags
dependencyPseudoMask |= selector.pseudoStateMask;
// the element matches this selector because it does not have those flags
triggerPseudoStateMask |= selector.negatedPseudoStateMask;
}
}
match &= isPartMatch;
}
var result = new MatchResultInfo()
{
success = match
};
if (match || failedOnlyOnPseudoStates)
{
result.triggerPseudoMask = (PseudoStates)triggerPseudoStateMask;
result.dependencyPseudoMask = (PseudoStates)dependencyPseudoMask;
}
return(result);
}
public override void OnProcessMatchResult(UIElements.VisualElement element, ref StyleSheets.RuleMatcher matcher, ref MatchResultInfo matchInfo)
{
element.triggerPseudoMask |= matchInfo.triggerPseudoMask;
element.dependencyPseudoMask |= matchInfo.dependencyPseudoMask;
}
private bool MatchRightToLeft(VisualElement element, ref RuleMatcher matcher)
{
// see https://speakerdeck.com/constellation/css-jit-just-in-time-compiled-css-selectors-in-webkit for
// a detailed explaination of the algorithm
var current = element;
int nextIndex = matcher.complexSelector.selectors.Length - 1;
VisualElement saved = null;
int savedIdx = -1;
// go backward
while (nextIndex >= 0)
{
if (current == null)
{
break;
}
MatchResultInfo matchInfo = Match(current, ref matcher, nextIndex);
OnProcessMatchResult(current, ref matcher, ref matchInfo);
if (!matchInfo.success)
{
// if we have a descendent relationship, keep trying on the parent
// ie. "div span", div failed on this element, try on the parent
// happens earlier than the backtracking saving below
if (nextIndex < matcher.complexSelector.selectors.Length - 1 &&
matcher.complexSelector.selectors[nextIndex + 1].previousRelationship == StyleSelectorRelationship.Descendent)
{
current = current.parent;
continue;
}
// otherwise, if there's a previous relationship, it's a 'child' one. backtrack from the saved point and try again
// ie. for "#x > .a .b", #x failed, backtrack to .a on the saved element
if (saved != null)
{
current = saved;
nextIndex = savedIdx;
continue;
}
break;
}
// backtracking save
// for "a > b c": we're considering the b matcher. c's previous relationship is Descendent
// save the current element parent to try to match b again
if (nextIndex < matcher.complexSelector.selectors.Length - 1 &&
matcher.complexSelector.selectors[nextIndex + 1].previousRelationship == StyleSelectorRelationship.Descendent)
{
saved = current.parent;
savedIdx = nextIndex;
}
// from now, the element is a match
if (--nextIndex < 0)
{
//TODO: abort if return false
if (OnRuleMatchedElement(matcher, element))
{
return(true);
}
}
current = current.parent;
}
return(false);
}
public virtual void OnProcessMatchResult(VisualElement element, ref RuleMatcher matcher, ref MatchResultInfo matchInfo)
{
}