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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.org 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):
- *
- * 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 ***** */
- #ifndef nsIStyleRule_h___
- #define nsIStyleRule_h___
-
- #include <stdio.h>
-
- #include "nsISupports.h"
-
- class nsIStyleSheet;
- class nsPresContext;
- class nsIContent;
- struct nsRuleData;
-
- // IID for the nsIStyleRule interface {40ae5c90-ad6a-11d1-8031-006008159b5a}
- #define NS_ISTYLE_RULE_IID \
- {0x40ae5c90, 0xad6a, 0x11d1, {0x80, 0x31, 0x00, 0x60, 0x08, 0x15, 0x9b, 0x5a}}
-
- /**
- * An object implementing |nsIStyleRule| (henceforth, a rule) represents
- * immutable stylistic information that either applies or does not apply
- * to a given element. It belongs to an object or group of objects that
- * implement |nsIStyleSheet| and |nsIStyleRuleProcessor| (henceforth, a
- * sheet).
- *
- * A rule becomes relevant to the computation of style data when
- * |nsIStyleRuleProcessor::RulesMatching| creates a rule node that
- * points to the rule. (A rule node, |nsRuleNode|, is a node in the
- * rule tree, which is a lexicographic tree indexed by rules. The path
- * from the root of the rule tree to the |nsRuleNode| for a given
- * |nsStyleContext| contains exactly the rules that match the element
- * that the style context is for, in priority (weight, origin,
- * specificity) order.)
- *
- * The computation of style data uses the rule tree, which calls
- * |nsIStyleRule::MapRuleInfoInto| below.
- *
- * It is worth emphasizing that the data represented by a rule
- * implementation are immutable. When the data need to be changed, a
- * new rule object must be created. Failing to do this will lead to
- * bugs in the handling of dynamic style changes, since the rule tree
- * caches the results of |MapRuleInfoInto|.
- *
- * |nsIStyleRule| objects are owned by |nsRuleNode| objects (in addition
- * to typically being owned by their sheet), which are in turn garbage
- * collected (with the garbage collection roots being style contexts).
- */
-
-
- class nsIStyleRule : public nsISupports {
- public:
- NS_DEFINE_STATIC_IID_ACCESSOR(NS_ISTYLE_RULE_IID)
-
- /**
- * |nsIStyleRule::MapRuleInfoInto| is a request to copy all stylistic
- * data represented by the rule that:
- * + are relevant for |aRuleData->mSID| (the style struct ID)
- * + are not already filled into the data struct
- * into the appropriate data struct in |aRuleData|. It is important
- * that only empty data are filled in, since the rule tree is walked
- * from highest priority rule to least, so that the walk can stop if
- * all needed data are found. Thus overwriting non-empty data will
- * break CSS cascading rules.
- */
- NS_IMETHOD MapRuleInfoInto(nsRuleData* aRuleData)=0;
-
- #ifdef DEBUG
- NS_IMETHOD List(FILE* out = stdout, PRInt32 aIndent = 0) const = 0;
- #endif
- };
-
-
- #endif /* nsIStyleRule_h___ */
-