/*
 * 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 TransforMiiX XSLT processor.
 * 
 * The Initial Developer of the Original Code is The MITRE Corporation.
 * Portions created by MITRE are Copyright (C) 1999 The MITRE Corporation.
 *
 * Portions created by Keith Visco as a Non MITRE employee,
 * (C) 1999 Keith Visco. All Rights Reserved.
 * 
 * Contributor(s): 
 * Keith Visco, kvisco@ziplink.net
 *   -- original author.
 * 
 */

#include "Expr.h"
#include "NodeSet.h"

  //-------------/
 //- UnionExpr -/
//-------------/


/**
 * Creates a new UnionExpr
**/
UnionExpr::UnionExpr() {
    //-- do nothing
}

/**
 * Destructor, will delete all Path Expressions
**/
UnionExpr::~UnionExpr() {
    txListIterator iter(&expressions);
    while (iter.hasNext()) {
         delete (Expr*)iter.next();
    }
} //-- ~UnionExpr

/**
 * Adds the Expr to this UnionExpr
 * @param expr the Expr to add to this UnionExpr
**/
void UnionExpr::addExpr(Expr* expr) {
    if (expr)
      expressions.add(expr);
} //-- addExpr

    //-----------------------------/
  //- Virtual methods from Expr -/
//-----------------------------/

/**
 * Evaluates this Expr based on the given context node and processor state
 * @param context the context node for evaluation of this Expr
 * @param ps the ContextState containing the stack information needed
 * for evaluation
 * @return the result of the evaluation
**/
ExprResult* UnionExpr::evaluate(txIEvalContext* aContext)
{
    NodeSet* nodes = new NodeSet();

    if (!aContext || (expressions.getLength() == 0) || !nodes)
        return nodes;

    txListIterator iter(&expressions);

    while (iter.hasNext()) {
        Expr* expr = (Expr*)iter.next();
        ExprResult* exprResult = expr->evaluate(aContext);
        if (!exprResult ||
            exprResult->getResultType() != ExprResult::NODESET) {
            delete exprResult;
            delete nodes;
            return new StringResult(NS_LITERAL_STRING("error"));
        }
        nodes->add((NodeSet*)exprResult);
        delete exprResult;
    }

    return nodes;
} //-- evaluate

/**
 * Returns the String representation of this Expr.
 * @param dest the String to use when creating the String
 * representation. The String representation will be appended to
 *  any data in the destination String, to allow cascading calls to
 * other #toString() methods for Expressions.
 * @return the String representation of this Expr.
**/
void UnionExpr::toString(nsAString& dest) {
    txListIterator iter(&expressions);

    short count = 0;
    while (iter.hasNext()) {
        //-- set operator
        if (count > 0)
            dest.Append(NS_LITERAL_STRING(" | "));
        ((Expr*)iter.next())->toString(dest);
        ++count;
    }
} //-- toString