RetroZilla/extensions/transformiix/source/xpath/BooleanExpr.cpp

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 * The Original Code is TransforMiiX XSLT processor code.
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 * The Initial Developer of the Original Code is
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 * Portions created by the Initial Developer are Copyright (C) 1999
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 * Contributor(s):
 *   Keith Visco <kvisco@ziplink.net> (Original Author)
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/**
 * Represents a BooleanExpr, a binary expression that
 * performs a boolean operation between it's lvalue and rvalue.
**/

#include "Expr.h"
#include "ExprResult.h"
#include "txIXPathContext.h"

/**
 * 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
**/
nsresult
BooleanExpr::evaluate(txIEvalContext* aContext, txAExprResult** aResult)
{
    *aResult = nsnull;

    nsRefPtr<txAExprResult> exprRes;
    nsresult rv = leftExpr->evaluate(aContext, getter_AddRefs(exprRes));
    NS_ENSURE_SUCCESS(rv, rv);
    
    PRBool lval = exprRes->booleanValue();

    // check for early decision
    if (op == OR && lval) {
        aContext->recycler()->getBoolResult(PR_TRUE, aResult);
        
        return NS_OK;
    }
    if (op == AND && !lval) {
        aContext->recycler()->getBoolResult(PR_FALSE, aResult);

        return NS_OK;
    }

    rv = rightExpr->evaluate(aContext, getter_AddRefs(exprRes));
    NS_ENSURE_SUCCESS(rv, rv);

    // just use rval, since we already checked lval
    aContext->recycler()->getBoolResult(exprRes->booleanValue(), aResult);

    return NS_OK;
} //-- evaluate

#ifdef TX_TO_STRING
void
BooleanExpr::toString(nsAString& str)
{
    if ( leftExpr ) leftExpr->toString(str);
    else str.AppendLiteral("null");

    switch ( op ) {
        case OR:
            str.AppendLiteral(" or ");
            break;
        default:
            str.AppendLiteral(" and ");
            break;
    }
    if ( rightExpr ) rightExpr->toString(str);
    else str.AppendLiteral("null");

}
#endif