layout/style/nsRuleWalker.h

   1 /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
   2 /* ***** BEGIN LICENSE BLOCK *****
   3  * Version: MPL 1.1/GPL 2.0/LGPL 2.1
   4  *
   5  * The contents of this file are subject to the Mozilla Public License Version
   6  * 1.1 (the "License"); you may not use this file except in compliance with
   7  * the License. You may obtain a copy of the License at
   8  * http://www.mozilla.org/MPL/
   9  *
  10  * Software distributed under the License is distributed on an "AS IS" basis,
  11  * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
  12  * for the specific language governing rights and limitations under the
  13  * License.
  14  *
  15  * The Original Code is Mozilla Communicator client code.
  16  *
  17  * The Initial Developer of the Original Code is
  18  * Netscape Communications Corporation.
  19  * Portions created by the Initial Developer are Copyright (C) 1998
  20  * the Initial Developer. All Rights Reserved.
  21  *
  22  * Contributor(s):
  23  *   Original Author: David W. Hyatt (hyatt@netscape.com)
  24  *
  25  * Alternatively, the contents of this file may be used under the terms of
  26  * either of the GNU General Public License Version 2 or later (the "GPL"),
  27  * or the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
  28  * in which case the provisions of the GPL or the LGPL are applicable instead
  29  * of those above. If you wish to allow use of your version of this file only
  30  * under the terms of either the GPL or the LGPL, and not to allow others to
  31  * use your version of this file under the terms of the MPL, indicate your
  32  * decision by deleting the provisions above and replace them with the notice
  33  * and other provisions required by the GPL or the LGPL. If you do not delete
  34  * the provisions above, a recipient may use your version of this file under
  35  * the terms of any one of the MPL, the GPL or the LGPL.
  36  *
  37  * ***** END LICENSE BLOCK ***** */
  38
  39 /*
  40  * a class that walks the lexicographic tree of rule nodes as style
  41  * rules are matched
  42  */
  43
  44 #include "nsRuleNode.h"
  45
  46 class nsRuleWalker {
  47 public:
  48   nsRuleNode* GetCurrentNode() { return mCurrent; }
  49   void SetCurrentNode(nsRuleNode* aNode) { mCurrent = aNode; }
  50
  51   void Forward(nsIStyleRule* aRule) {
  52     if (mCurrent) { // check for OOM from previous step
  53       mCurrent = mCurrent->Transition(aRule, mLevel, mImportance);
  54     }
  55   }
  56
  57   void Reset() { mCurrent = mRoot; }
  58
  59   PRBool AtRoot() { return mCurrent == mRoot; }
  60
  61   void SetLevel(PRUint8 aLevel, PRBool aImportance) {
  62     mLevel = aLevel;
  63     mImportance = aImportance;
  64   }
  65   PRUint8 GetLevel() const { return mLevel; }
  66   PRBool GetImportance() const { return mImportance; }
  67
  68 private:
  69   nsRuleNode* mCurrent; // Our current position.
  70   nsRuleNode* mRoot; // The root of the tree we're walking.
  71   PRUint8 mLevel; // an nsStyleSet::sheetType
  72   PRPackedBool mImportance;
  73
  74 public:
  75   nsRuleWalker(nsRuleNode* aRoot) :mCurrent(aRoot), mRoot(aRoot) { MOZ_COUNT_CTOR(nsRuleWalker); }
  76   ~nsRuleWalker() { MOZ_COUNT_DTOR(nsRuleWalker); }
  77 };