gecko-dev/layout/style/nsRuleProcessorData.h

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 *   L. David Baron <dbaron@dbaron.org>, Mozilla Corporation
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/*
 * data structures passed to nsIStyleRuleProcessor methods (to pull loop
 * invariant computations out of the loop)
 */

#ifndef nsRuleProcessorData_h_
#define nsRuleProcessorData_h_

#include "nsPresContext.h" // for nsCompatability
#include "nsString.h"
#include "nsChangeHint.h"
#include "nsIContent.h"
#include "nsCSSPseudoElements.h"
#include "nsRuleWalker.h"
#include "nsNthIndexCache.h"

class nsIStyleSheet;
class nsIAtom;
class nsICSSPseudoComparator;
class nsAttrValue;

/**
 * A |TreeMatchContext| has data about a matching operation.  The
 * data are not node-specific but are invariants of the DOM tree the
 * nodes being matched against are in.
 *
 * Most of the members are in parameters to selector matching.  The
 * one out parameter is mHaveRelevantLink.  Consumers that use a
 * TreeMatchContext for more than one matching operation need to reset
 * mHaveRelevantLink if they care about the return value.
 */
struct NS_STACK_CLASS TreeMatchContext {
  // Is this matching operation for the creation of a style context?
  // (If it is, we need to set slow selector bits on nodes indicating
  // that certain restyling needs to happen.)
  const PRBool mForStyling;

  // Did this matching operation find a relevant link?  (If so, we'll
  // need to construct a StyleIfVisited.)
  PRBool mHaveRelevantLink;

  // How matching should be performed.  See the documentation for
  // nsRuleWalker::VisitedHandlingType.
  nsRuleWalker::VisitedHandlingType mVisitedHandling;

  // The document we're working with.
  nsIDocument* const mDocument;

  // Root of scoped stylesheet (set and unset by the supplier of the
  // scoped stylesheet).
  nsIContent* mScopedRoot;

  // Whether our document is HTML (as opposed to XML of some sort,
  // including XHTML).
  // XXX XBL2 issue: Should we be caching this?  What should it be for XBL2?
  const PRPackedBool mIsHTMLDocument;

  // Possibly remove use of mCompatMode in SelectorMatches?
  // XXX XBL2 issue: Should we be caching this?  What should it be for XBL2?
  const nsCompatibility mCompatMode;

  // The nth-index cache we should use
  nsNthIndexCache mNthIndexCache;

  TreeMatchContext(PRBool aForStyling,
                   nsRuleWalker::VisitedHandlingType aVisitedHandling,
                   nsIDocument* aDocument)
    : mForStyling(aForStyling)
    , mHaveRelevantLink(PR_FALSE)
    , mVisitedHandling(aVisitedHandling)
    , mDocument(aDocument)
    , mScopedRoot(nsnull)
    , mIsHTMLDocument(aDocument->IsHTML())
    , mCompatMode(aDocument->GetCompatibilityMode())
  {
  }
};

// The implementation of the constructor and destructor are currently in
// nsCSSRuleProcessor.cpp.

struct NS_STACK_CLASS RuleProcessorData : public TreeMatchContext {
  RuleProcessorData(nsPresContext* aPresContext,
                    mozilla::dom::Element* aElement, 
                    nsRuleWalker* aRuleWalker,
                    PRBool aForStyling)
    : TreeMatchContext(aForStyling,
                       aRuleWalker ?
                         aRuleWalker->VisitedHandling() :
                         nsRuleWalker::eLinksVisitedOrUnvisited,
                       aElement->GetOwnerDoc())
    , mPresContext(aPresContext)
    , mElement(aElement)
    , mRuleWalker(aRuleWalker)
  {
    NS_ASSERTION(aElement, "null element leaked into SelectorMatches");
    NS_ASSERTION(aElement->GetOwnerDoc(), "Document-less node here?");
  }
  
  // Reset this data for matching for the style-if-:visited.  This should
  // only be called for RuleProcessorData objects which have a rulewalker.
  void ResetForVisitedMatching() {
    mHaveRelevantLink = PR_FALSE;
    mRuleWalker->ResetForVisitedMatching();
    mVisitedHandling = mRuleWalker->VisitedHandling();
  }
  
  nsPresContext* const mPresContext;
  mozilla::dom::Element* const mElement; // weak ref, must not be null
  nsRuleWalker* const mRuleWalker; // Used to add rules to our results.
};

struct NS_STACK_CLASS ElementRuleProcessorData : public RuleProcessorData {
  ElementRuleProcessorData(nsPresContext* aPresContext,
                           mozilla::dom::Element* aElement, 
                           nsRuleWalker* aRuleWalker)
  : RuleProcessorData(aPresContext, aElement, aRuleWalker, PR_TRUE)
  {
    NS_PRECONDITION(aPresContext, "null pointer");
    NS_PRECONDITION(aRuleWalker, "null pointer");
  }
};

struct NS_STACK_CLASS PseudoElementRuleProcessorData : public RuleProcessorData {
  PseudoElementRuleProcessorData(nsPresContext* aPresContext,
                                 mozilla::dom::Element* aParentElement,
                                 nsRuleWalker* aRuleWalker,
                                 nsCSSPseudoElements::Type aPseudoType)
    : RuleProcessorData(aPresContext, aParentElement, aRuleWalker, PR_TRUE),
      mPseudoType(aPseudoType)
  {
    NS_PRECONDITION(aPresContext, "null pointer");
    NS_PRECONDITION(aPseudoType <
                      nsCSSPseudoElements::ePseudo_PseudoElementCount,
                    "null pointer");
    NS_PRECONDITION(aRuleWalker, "null pointer");
  }

  nsCSSPseudoElements::Type mPseudoType;
};

struct NS_STACK_CLASS AnonBoxRuleProcessorData {
  AnonBoxRuleProcessorData(nsPresContext* aPresContext,
                           nsIAtom* aPseudoTag,
                           nsRuleWalker* aRuleWalker)
    : mPresContext(aPresContext),
      mPseudoTag(aPseudoTag),
      mRuleWalker(aRuleWalker)
  {
    NS_PRECONDITION(mPresContext, "Must have prescontext");
    NS_PRECONDITION(aPseudoTag, "Must have pseudo tag");
    NS_PRECONDITION(aRuleWalker, "Must have rule walker");
  }

  nsPresContext* mPresContext;
  nsIAtom* mPseudoTag;
  nsRuleWalker* mRuleWalker;
};

#ifdef MOZ_XUL
struct NS_STACK_CLASS XULTreeRuleProcessorData : public RuleProcessorData {
  XULTreeRuleProcessorData(nsPresContext* aPresContext,
                           mozilla::dom::Element* aParentElement,
                           nsRuleWalker* aRuleWalker,
                           nsIAtom* aPseudoTag,
                           nsICSSPseudoComparator* aComparator)
    : RuleProcessorData(aPresContext, aParentElement, aRuleWalker, PR_TRUE),
      mPseudoTag(aPseudoTag),
      mComparator(aComparator)
  {
    NS_PRECONDITION(aPresContext, "null pointer");
    NS_PRECONDITION(aPseudoTag, "null pointer");
    NS_PRECONDITION(aRuleWalker, "null pointer");
    NS_PRECONDITION(aComparator, "must have a comparator");
  }

  nsIAtom*                 mPseudoTag;
  nsICSSPseudoComparator*  mComparator;
};
#endif

struct NS_STACK_CLASS StateRuleProcessorData : public RuleProcessorData {
  StateRuleProcessorData(nsPresContext* aPresContext,
                         mozilla::dom::Element* aElement,
                         nsEventStates aStateMask)
    : RuleProcessorData(aPresContext, aElement, nsnull, PR_FALSE),
      mStateMask(aStateMask)
  {
    NS_PRECONDITION(aPresContext, "null pointer");
  }
  const nsEventStates mStateMask; // |HasStateDependentStyle| for which state(s)?
                                  //  Constants defined in nsEventStates.h .
};

struct NS_STACK_CLASS AttributeRuleProcessorData : public RuleProcessorData {
  AttributeRuleProcessorData(nsPresContext* aPresContext,
                             mozilla::dom::Element* aElement,
                             nsIAtom* aAttribute,
                             PRInt32 aModType,
                             PRBool aAttrHasChanged)
    : RuleProcessorData(aPresContext, aElement, nsnull, PR_FALSE),
      mAttribute(aAttribute),
      mModType(aModType),
      mAttrHasChanged(aAttrHasChanged)
  {
    NS_PRECONDITION(aPresContext, "null pointer");
  }
  nsIAtom* mAttribute; // |HasAttributeDependentStyle| for which attribute?
  PRInt32 mModType;    // The type of modification (see nsIDOMMutationEvent).
  PRBool mAttrHasChanged; // Whether the attribute has already changed.
};

#endif /* !defined(nsRuleProcessorData_h_) */