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lightning-sunbird  0.9+nobinonly
PredicateList.cpp
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00001 /* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
00002 /* ***** BEGIN LICENSE BLOCK *****
00003  * Version: MPL 1.1/GPL 2.0/LGPL 2.1
00004  *
00005  * The contents of this file are subject to the Mozilla Public License Version
00006  * 1.1 (the "License"); you may not use this file except in compliance with
00007  * the License. You may obtain a copy of the License at
00008  * http://www.mozilla.org/MPL/
00009  *
00010  * Software distributed under the License is distributed on an "AS IS" basis,
00011  * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
00012  * for the specific language governing rights and limitations under the
00013  * License.
00014  *
00015  * The Original Code is TransforMiiX XSLT processor code.
00016  *
00017  * The Initial Developer of the Original Code is
00018  * The MITRE Corporation.
00019  * Portions created by the Initial Developer are Copyright (C) 1999
00020  * the Initial Developer. All Rights Reserved.
00021  *
00022  * Contributor(s):
00023  *   Keith Visco <kvisco@ziplink.net> (Original Author)
00024  *
00025  * Alternatively, the contents of this file may be used under the terms of
00026  * either the GNU General Public License Version 2 or later (the "GPL"), or
00027  * the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
00028  * in which case the provisions of the GPL or the LGPL are applicable instead
00029  * of those above. If you wish to allow use of your version of this file only
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00031  * use your version of this file under the terms of the MPL, indicate your
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00033  * and other provisions required by the GPL or the LGPL. If you do not delete
00034  * the provisions above, a recipient may use your version of this file under
00035  * the terms of any one of the MPL, the GPL or the LGPL.
00036  *
00037  * ***** END LICENSE BLOCK ***** */
00038 
00039 #include "Expr.h"
00040 #include "txNodeSet.h"
00041 #include "txNodeSetContext.h"
00042 
00043 /*
00044  * Represents an ordered list of Predicates,
00045  * for use with Step and Filter Expressions
00046  */
00047 
00048 PredicateList::PredicateList()
00049 {
00050 } // PredicateList
00051 
00052 /*
00053  * Destructor, will delete all Expressions in the list
00054  */
00055 PredicateList::~PredicateList()
00056 {
00057     txListIterator iter(&predicates);
00058     while (iter.hasNext()) {
00059         delete (Expr*)iter.next();
00060     }
00061 } // ~PredicateList
00062 
00063 /*
00064  * Adds the given Expr to the list
00065  * @param expr the Expr to add to the list
00066  */
00067 nsresult
00068 PredicateList::add(Expr* aExpr)
00069 {
00070     NS_ASSERTION(aExpr, "missing expression");
00071     nsresult rv = predicates.add(aExpr);
00072     if (NS_FAILED(rv)) {
00073         delete aExpr;
00074     }
00075     return rv;
00076 } // add
00077 
00078 nsresult
00079 PredicateList::evaluatePredicates(txNodeSet* nodes,
00080                                   txIMatchContext* aContext)
00081 {
00082     NS_ASSERTION(nodes, "called evaluatePredicates with NULL NodeSet");
00083     nsresult rv = NS_OK;
00084 
00085     txListIterator iter(&predicates);
00086     while (iter.hasNext() && !nodes->isEmpty()) {
00087         Expr* expr = (Expr*)iter.next();
00088         txNodeSetContext predContext(nodes, aContext);
00089         /*
00090          * add nodes to newNodes that match the expression
00091          * or, if the result is a number, add the node with the right
00092          * position
00093          */
00094         PRInt32 index = 0;
00095         while (predContext.hasNext()) {
00096             predContext.next();
00097             nsRefPtr<txAExprResult> exprResult;
00098             rv = expr->evaluate(&predContext, getter_AddRefs(exprResult));
00099             NS_ENSURE_SUCCESS(rv, rv);
00100 
00101             // handle default, [position() == numberValue()]
00102             if (exprResult->getResultType() == txAExprResult::NUMBER) {
00103                 if ((double)predContext.position() == exprResult->numberValue()) {
00104                     nodes->mark(index);
00105                 }
00106             }
00107             else if (exprResult->booleanValue()) {
00108                 nodes->mark(index);
00109             }
00110             ++index;
00111         }
00112         // sweep the non-marked nodes
00113         nodes->sweep();
00114     }
00115 
00116     return NS_OK;
00117 }
00118 
00119 /*
00120  * returns true if this predicate list is empty
00121  */
00122 MBool PredicateList::isEmpty()
00123 {
00124     return (MBool)(predicates.getLength() == 0);
00125 } // isEmpty
00126 
00127 #ifdef TX_TO_STRING
00128 void PredicateList::toString(nsAString& dest)
00129 {
00130     txListIterator iter(&predicates);
00131     while (iter.hasNext()) {
00132         Expr* expr = (Expr*) iter.next();
00133         dest.Append(PRUnichar('['));
00134         expr->toString(dest);
00135         dest.Append(PRUnichar(']'));
00136     }
00137 }
00138 #endif