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Introduce NodeMatchContext for additional input into SelectorMatches. (Bug 147777) r=bzbarsky

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This commit is contained in:
L. David Baron 2010-04-02 18:58:26 -07:00
parent 9b0db9e924
commit 179665d6ce
1 changed files with 45 additions and 20 deletions
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65
layout/style/nsCSSRuleProcessor.cpp
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@ -1219,10 +1219,6 @@ RuleProcessorData::GetNthIndex(PRBool aIsOfType, PRBool aIsFromEnd,
* A |TreeMatchContext| has data about matching a selector (containing
* combinators) against a node and the tree that that node is in. It
* contains both input to and output from the matching.
*
* (In contrast, a RuleProcessorData has information needed to match a
* selector (without combinators) against a single node; it only
* has input to the matching.)
*/
struct TreeMatchContext {
// Is this matching operation for the creation of a style context?
@ -1236,6 +1232,36 @@ struct TreeMatchContext {
}
};
/**
* A |NodeMatchContext| has data about matching a selector (without
* combinators) against a single node. It contains only input to the
* matching.
*
* Unlike |RuleProcessorData|, which is similar, a |NodeMatchContext|
* can vary depending on the selector matching process. In other words,
* there might be multiple NodeMatchContexts corresponding to a single
* node, but only one possible RuleProcessorData.
*/
struct NodeMatchContext {
// In order to implement nsCSSRuleProcessor::HasStateDependentStyle,
// we need to be able to see if a node might match an
// event-state-dependent selector for any value of that event state.
// So mStateMask contains the states that should NOT be tested.
//
// NOTE: For |aStateMask| to work correctly, it's important that any
// change that changes multiple state bits include all those state
// bits in the notification. Otherwise, if multiple states change but
// we do separate notifications then we might determine the style is
// not state-dependent when it really is (e.g., determining that a
// :hover:active rule no longer matches when both states are unset).
const PRInt32 mStateMask;
NodeMatchContext(PRInt32 aStateMask)
: mStateMask(aStateMask)
{
}
};
static PRBool ValueIncludes(const nsSubstring& aValueList,
const nsSubstring& aValue,
const nsStringComparator& aComparator)
@ -1834,13 +1860,6 @@ static const PseudoClassInfo sPseudoClassInfo[] = {
PR_STATIC_ASSERT(NS_ARRAY_LENGTH(sPseudoClassInfo) >
nsCSSPseudoClasses::ePseudoClass_NotPseudoClass);
// NOTE: For |aStateMask| to work correctly, it's important that any change
// that changes multiple state bits include all those state bits in the
// notification. Otherwise, if multiple states change but we do separate
// notifications then we might determine the style is not state-dependent when
// it really is (e.g., determining that a :hover:active rule no longer matches
// when both states are unset).
// |aDependence| has two functions:
// * when non-null, it indicates that we're processing a negation,
// which is done only when SelectorMatches calls itself recursively
@ -1848,7 +1867,7 @@ PR_STATIC_ASSERT(NS_ARRAY_LENGTH(sPseudoClassInfo) >
// because of aStateMask
static PRBool SelectorMatches(RuleProcessorData &data,
nsCSSSelector* aSelector,
PRInt32 aStateMask, // states NOT to test
NodeMatchContext& aNodeMatchContext,
TreeMatchContext& aTreeMatchContext,
PRBool* const aDependence = nsnull)
@ -1929,7 +1948,8 @@ static PRBool SelectorMatches(RuleProcessorData &data,
// generally quick to test, and thus earlier). If they were later,
// we'd probably avoid setting those bits in more cases where setting
// them is unnecessary.
NS_ASSERTION(aStateMask == 0 || !aTreeMatchContext.mForStyling,
NS_ASSERTION(aNodeMatchContext.mStateMask == 0 ||
!aTreeMatchContext.mForStyling,
"mForStyling must be false if we're just testing for "
"state-dependence");
@ -1961,7 +1981,7 @@ static PRBool SelectorMatches(RuleProcessorData &data,
// selectors ":hover" and ":active".
return PR_FALSE;
} else {
if (aStateMask & statesToCheck) {
if (aNodeMatchContext.mStateMask & statesToCheck) {
if (aDependence)
*aDependence = PR_TRUE;
} else {
@ -2056,7 +2076,7 @@ static PRBool SelectorMatches(RuleProcessorData &data,
for (nsCSSSelector *negation = aSelector->mNegations;
result && negation; negation = negation->mNegations) {
PRBool dependence = PR_FALSE;
result = !SelectorMatches(data, negation, aStateMask,
result = !SelectorMatches(data, negation, aNodeMatchContext,
aTreeMatchContext, &dependence);
// If the selector does match due to the dependence on aStateMask,
// then we want to keep result true so that the final result of
@ -2138,7 +2158,8 @@ static PRBool SelectorMatchesTree(RuleProcessorData& aPrevData,
if (! data) {
return PR_FALSE;
}
if (SelectorMatches(*data, selector, 0, aTreeMatchContext)) {
NodeMatchContext nodeContext(0);
if (SelectorMatches(*data, selector, nodeContext, aTreeMatchContext)) {
// to avoid greedy matching, we need to recur if this is a
// descendant or general sibling combinator and the next
// combinator is different, but we can make an exception for
@ -2182,7 +2203,8 @@ static void ContentEnumFunc(nsICSSStyleRule* aRule, nsCSSSelector* aSelector,
RuleProcessorData* data = (RuleProcessorData*)aData;
TreeMatchContext treeContext(PR_TRUE);
if (SelectorMatches(*data, aSelector, 0, treeContext)) {
NodeMatchContext nodeContext(0);
if (SelectorMatches(*data, aSelector, nodeContext, treeContext)) {
nsCSSSelector *next = aSelector->mNext;
if (!next || SelectorMatchesTree(*data, next, treeContext)) {
// for performance, require that every implementation of
@ -2333,8 +2355,9 @@ nsCSSRuleProcessor::HasStateDependentStyle(StateRuleProcessorData* aData)
// don't bother calling SelectorMatches, since even if it returns false
// hint won't change.
TreeMatchContext treeContext(PR_FALSE);
NodeMatchContext nodeContext(aData->mStateMask);
if ((possibleChange & ~hint) &&
SelectorMatches(*aData, selector, aData->mStateMask, treeContext) &&
SelectorMatches(*aData, selector, nodeContext, treeContext) &&
SelectorMatchesTree(*aData, selector->mNext, treeContext)) {
hint = nsRestyleHint(hint | possibleChange);
}
@ -2372,8 +2395,9 @@ AttributeEnumFunc(nsCSSSelector* aSelector, AttributeEnumData* aData)
// bother calling SelectorMatches, since even if it returns false
// enumData->change won't change.
TreeMatchContext treeContext(PR_FALSE);
NodeMatchContext nodeContext(0);
if ((possibleChange & ~(aData->change)) &&
SelectorMatches(*data, aSelector, 0, treeContext) &&
SelectorMatches(*data, aSelector, nodeContext, treeContext) &&
SelectorMatchesTree(*data, aSelector->mNext, treeContext)) {
aData->change = nsRestyleHint(aData->change | possibleChange);
}
@ -2916,7 +2940,8 @@ nsCSSRuleProcessor::SelectorListMatches(RuleProcessorData& aData,
NS_ASSERTION(sel, "Should have *some* selectors");
NS_ASSERTION(!sel->IsPseudoElement(), "Shouldn't have been called");
TreeMatchContext treeContext(PR_FALSE);
if (SelectorMatches(aData, sel, 0, treeContext)) {
NodeMatchContext nodeContext(0);
if (SelectorMatches(aData, sel, nodeContext, treeContext)) {
nsCSSSelector* next = sel->mNext;
if (!next || SelectorMatchesTree(aData, next, treeContext)) {
return PR_TRUE;