gecko-dev/layout/style/nsRuleWalker.h

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/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* ***** BEGIN LICENSE BLOCK *****
* Version: MPL 1.1/GPL 2.0/LGPL 2.1
*
* 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
* the License. You may obtain a copy of the License at
* http://www.mozilla.org/MPL/
*
* Software distributed under the License is distributed on an "AS IS" basis,
* WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
* for the specific language governing rights and limitations under the
* License.
*
* The Original Code is Mozilla Communicator client code.
*
* The Initial Developer of the Original Code is
* Netscape Communications Corporation.
* Portions created by the Initial Developer are Copyright (C) 1998
* the Initial Developer. All Rights Reserved.
*
* Contributor(s):
* Original Author: David W. Hyatt (hyatt@netscape.com)
*
* Alternatively, the contents of this file may be used under the terms of
* either of the GNU General Public License Version 2 or later (the "GPL"),
* or the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
* in which case the provisions of the GPL or the LGPL are applicable instead
* of those above. If you wish to allow use of your version of this file only
* under the terms of either the GPL or the LGPL, and not to allow others to
* use your version of this file under the terms of the MPL, indicate your
* decision by deleting the provisions above and replace them with the notice
* and other provisions required by the GPL or the LGPL. If you do not delete
* the provisions above, a recipient may use your version of this file under
* the terms of any one of the MPL, the GPL or the LGPL.
*
* ***** END LICENSE BLOCK ***** */
/*
* a class that walks the lexicographic tree of rule nodes as style
* rules are matched
*/
#ifndef nsRuleWalker_h_
#define nsRuleWalker_h_
#include "nsRuleNode.h"
#include "nsIStyleRule.h"
class nsRuleWalker {
public:
nsRuleNode* CurrentNode() { return mCurrent; }
void SetCurrentNode(nsRuleNode* aNode) {
NS_ASSERTION(aNode, "Must have node here!");
mCurrent = aNode;
}
void Forward(nsIStyleRule* aRule) {
mCurrent = mCurrent->Transition(aRule, mLevel, mImportance);
mCheckForImportantRules =
mCheckForImportantRules && !aRule->GetImportantRule();
NS_POSTCONDITION(mCurrent, "Transition messed up");
}
void Reset() { mCurrent = mRoot; }
PRBool AtRoot() { return mCurrent == mRoot; }
void SetLevel(PRUint8 aLevel, PRBool aImportance,
PRBool aCheckForImportantRules) {
NS_ASSERTION(!aCheckForImportantRules || !aImportance,
"Shouldn't be checking for important rules while walking "
"important rules");
mLevel = aLevel;
mImportance = aImportance;
mCheckForImportantRules = aCheckForImportantRules;
}
PRUint8 GetLevel() const { return mLevel; }
PRBool GetImportance() const { return mImportance; }
PRBool GetCheckForImportantRules() const { return mCheckForImportantRules; }
// We define the visited-relevant link to be the link that is the
// nearest self-or-ancestor to the node being matched.
enum VisitedHandlingType {
// Do rule matching as though all links are unvisited.
eRelevantLinkUnvisited,
// Do rule matching as though the relevant link is visited and all
// other links are unvisited.
eRelevantLinkVisited,
// Do rule matching as though a rule should match if it would match
// given any set of visitedness states. (used by users other than
// nsRuleWalker)
eLinksVisitedOrUnvisited
};
void ResetForVisitedMatching() {
Reset();
mVisitedHandling = eRelevantLinkVisited;
}
VisitedHandlingType VisitedHandling() const { return mVisitedHandling; }
void SetHaveRelevantLink() { mHaveRelevantLink = PR_TRUE; }
PRBool HaveRelevantLink() const { return mHaveRelevantLink; }
private:
nsRuleNode* mCurrent; // Our current position. Never null.
nsRuleNode* mRoot; // The root of the tree we're walking.
PRUint8 mLevel; // an nsStyleSet::sheetType
PRPackedBool mImportance;
PRPackedBool mCheckForImportantRules; // If true, check for important rules as
// we walk and set to false if we find
// one.
// When mVisitedHandling is eRelevantLinkUnvisited, this is set to
// true on the RuleProcessorData *for the node being matched* if a
// relevant link (see explanation in definition of VisitedHandling
// enum) was encountered during the matching process, which means that
// matching needs to be rerun with eRelevantLinkVisited. Otherwise,
// its behavior is undefined (it might get set appropriately, or might
// not).
PRBool mHaveRelevantLink;
VisitedHandlingType mVisitedHandling;
public:
nsRuleWalker(nsRuleNode* aRoot)
: mCurrent(aRoot)
, mRoot(aRoot)
, mHaveRelevantLink(PR_FALSE)
, mVisitedHandling(eRelevantLinkUnvisited)
{
NS_ASSERTION(mCurrent, "Caller screwed up and gave us null node");
MOZ_COUNT_CTOR(nsRuleWalker);
}
~nsRuleWalker() { MOZ_COUNT_DTOR(nsRuleWalker); }
};
#endif /* !defined(nsRuleWalker_h_) */