gecko/layout/style/nsCSSRuleProcessor.h

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/* ***** BEGIN LICENSE BLOCK *****
 * Version: MPL 1.1/GPL 2.0/LGPL 2.1
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 * The contents of this file are subject to the Mozilla Public License Version
 * 1.1 (the "License"); you may not use this file except in compliance with
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 *
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 * for the specific language governing rights and limitations under the
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 * The Original Code is mozilla.org code.
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 * The Initial Developer of the Original Code is
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 * Portions created by the Initial Developer are Copyright (C) 1998
 * the Initial Developer. All Rights Reserved.
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 * Contributor(s):
 *   L. David Baron <dbaron@dbaron.org>
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 * or the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
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/*
 * style rule processor for CSS style sheets, responsible for selector
 * matching and cascading
 */

#ifndef nsCSSRuleProcessor_h_
#define nsCSSRuleProcessor_h_

#include "nsIStyleRuleProcessor.h"
#include "nsCSSStyleSheet.h"
#include "nsTArray.h"
#include "nsAutoPtr.h"
#include "nsCSSRules.h"

struct RuleCascadeData;
struct nsCSSSelectorList;

/**
 * The CSS style rule processor provides a mechanism for sibling style
 * sheets to combine their rule processing in order to allow proper
 * cascading to happen.
 *
 * CSS style rule processors keep a live reference on all style sheets
 * bound to them.  The CSS style sheets keep a weak reference to all the
 * processors that they are bound to (many to many).  The CSS style sheet
 * is told when the rule processor is going away (via DropRuleProcessor).
 */

class nsCSSRuleProcessor: public nsIStyleRuleProcessor {
public:
  nsCSSRuleProcessor(const nsCOMArray<nsICSSStyleSheet>& aSheets, 
                     PRUint8 aSheetType);
  virtual ~nsCSSRuleProcessor();

  NS_DECL_ISUPPORTS

public:
  nsresult ClearRuleCascades();

  static void Startup();
  static void FreeSystemMetrics();
  static PRBool HasSystemMetric(nsIAtom* aMetric);

  /*
   * Returns true if the given RuleProcessorData matches one of the
   * selectors in aSelectorList.  Note that this method will assume
   * the matching is not for styling purposes.
   */
  static PRBool SelectorListMatches(RuleProcessorData& aData,
                                    nsCSSSelectorList* aSelectorList);

  // nsIStyleRuleProcessor
  NS_IMETHOD RulesMatching(ElementRuleProcessorData* aData);

  NS_IMETHOD RulesMatching(PseudoElementRuleProcessorData* aData);

  NS_IMETHOD RulesMatching(AnonBoxRuleProcessorData* aData);

  NS_IMETHOD RulesMatching(PseudoRuleProcessorData* aData);

  NS_IMETHOD HasStateDependentStyle(StateRuleProcessorData* aData,
                                    nsReStyleHint* aResult);

  virtual nsReStyleHint
    HasAttributeDependentStyle(AttributeRuleProcessorData* aData);

  NS_IMETHOD MediumFeaturesChanged(nsPresContext* aPresContext,
                                   PRBool* aRulesChanged);

  // Append all the currently-active font face rules to aArray.  Return
  // true for success and false for failure.
  PRBool AppendFontFaceRules(nsPresContext* aPresContext,
                             nsTArray<nsFontFaceRuleContainer>& aArray);

#ifdef DEBUG
  void AssertQuirksChangeOK() {
    NS_ASSERTION(!mRuleCascades, "can't toggle quirks style sheet without "
                                 "clearing rule cascades");
  }
#endif

private:
  static PRBool CascadeSheetEnumFunc(nsICSSStyleSheet* aSheet, void* aData);

  RuleCascadeData* GetRuleCascade(nsPresContext* aPresContext);
  void RefreshRuleCascade(nsPresContext* aPresContext);

  // The sheet order here is the same as in nsStyleSet::mSheets
  nsCOMArray<nsICSSStyleSheet> mSheets;

  // active first, then cached (most recent first)
  RuleCascadeData* mRuleCascades;

  // The last pres context for which GetRuleCascades was called.
  nsPresContext *mLastPresContext;
  
  // type of stylesheet using this processor
  PRUint8 mSheetType;  // == nsStyleSet::sheetType
};

#endif /* nsCSSRuleProcessor_h_ */