path.cpp

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/*
 * path.cc - Copyright 2005 Frerich Raabe <raabe@kde.org>
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */
#include "path.h"

#include "xml/dom_docimpl.h"
#include "xml/dom_nodeimpl.h"

using namespace DOM;
using namespace khtml;
using namespace khtml::XPath;

Filter::Filter( Expression *expr, const QList<Predicate *> &predicates )
    : m_expr( expr ),
    m_predicates( predicates )
{
}

Filter::~Filter()
{
    delete m_expr;
    qDeleteAll( m_predicates );
}

QString Filter::dump() const
{
    QString s = "<filter>";
    s += m_expr->dump();
    foreach( Predicate *predicate, m_predicates ) {
        s += predicate->dump();
    }
    s += "</filter>";
    return s;
}

Value Filter::doEvaluate() const
{
    Value v = m_expr->evaluate();
    if ( !v.isNodeset() ) {
        if ( !m_predicates.empty() ) {
            kDebug(6011) << "Ignoring predicates for filter since expression does not evaluate to a nodeset!";
        }
        return v;
    }

    DomNodeList inNodes = v.toNodeset(), outNodes;

    // Filter seems to work in document order, not axis order
    inNodes->normalizeUpto(StaticNodeListImpl::DocumentOrder);

    foreach( Predicate *predicate, m_predicates ) {
        outNodes = new StaticNodeListImpl();
        Expression::evaluationContext().size = int(inNodes->length());

        for ( unsigned long n = 0; n < inNodes->length(); ++n ) {
            NodeImpl *node = inNodes->item(n);
            Expression::evaluationContext().node = node;
            Expression::evaluationContext().position = n + 1;

            if ( predicate->evaluate() ) {
                outNodes->append( node );
            }
        }

        inNodes = outNodes;
        outNodes->setKnownNormalization(StaticNodeListImpl::DocumentOrder);

#ifdef XPATH_VERBOSE
        kDebug(6011) << "Predicate within filter trims to:" << outNodes->length();
#endif
    }

    return Value( outNodes );
}

LocationPath::LocationPath()
    : m_absolute( false )
{
}

LocationPath::~LocationPath()
{
    qDeleteAll( m_steps );
}

void LocationPath::optimize()
{
    foreach( Step *step, m_steps ) {
        step->optimize();
    }
}

Value LocationPath::doEvaluate() const
{
#ifdef XPATH_VERBOSE
    if ( m_absolute ) {
        kDebug(6011) << "Evaluating absolute path expression, steps:" << m_steps.count();
    } else {
        kDebug(6011) << "Evaluating relative path expression, steps:" << m_steps.count();
    }
#endif

    DomNodeList inDomNodes  = new StaticNodeListImpl,
                outDomNodes;

    /* For absolute location paths, the context node is ignored - the
     * document's root node is used instead.
     */
    NodeImpl *context = Expression::evaluationContext().node;
    if ( m_absolute ) {
        if ( context->nodeType() != Node::DOCUMENT_NODE ) {
            context = context->ownerDocument();
        }
    }

    inDomNodes->append( context );

    if ( m_steps.isEmpty() )
        return Value( inDomNodes );

    int s = 0;
    foreach( Step *step, m_steps ) {
#ifdef XPATH_VERBOSE
        kDebug(6011) << "-------------------------------------";
        kDebug(6011) << "Step " << s << "insize " << inDomNodes->length();
#endif      

        outDomNodes = new StaticNodeListImpl;
        for ( unsigned long i = 0; i < inDomNodes->length(); ++i ) {
            DomNodeList matches = step->evaluate( inDomNodes->item( i ) );
            for ( unsigned long j = 0; j < matches->length(); ++j )
                outDomNodes->append( matches->item( j ) );
        }
        inDomNodes = outDomNodes;

        ++s;
    }

#ifdef XPATH_VERBOSE
    kDebug(6011) << "-------------------------------------";
    kDebug(6011) << "output:" <<outDomNodes->length();
    kDebug(6011) << "=====================================";
#endif

    return Value( outDomNodes );
}

QString LocationPath::dump() const
{
    QString s = "<locationpath absolute=\"";
    s += m_absolute ? "true" : "false";
    s += "\">";
    foreach( Step *step, m_steps ) {
        s += step->dump();
    }
    s += "</locationpath>";
    return s;
}

Path::Path( Filter *filter, LocationPath *path )
    : m_filter( filter ),
    m_path( path )
{
}

Path::~Path()
{
    delete m_filter;
    delete m_path;
}

QString Path::dump() const
{
    if ( !m_filter && !m_path ) {
        return "<path/>";
    }

    QString s = "<path>";
    if ( m_filter ) {
        s += m_filter->dump();
    }
    if ( m_path ) {
        s += m_path->dump();
    }
    s += "</path>";

    return s;
}

Value Path::doEvaluate() const
{
    NodeImpl* saveCtx = Expression::evaluationContext().node;

    Value initial =  m_filter->evaluate();
    if ( initial.isNodeset() ) {
        // Pass in every output from the filter to the path, and union the results
        DomNodeList out = new StaticNodeListImpl();
        DomNodeList in  = initial.toNodeset();

        for (unsigned long i = 0; i < in->length(); ++i) {
            Expression::evaluationContext().node = in->item(i);

            DomNodeList singleSet = m_path->evaluate().toNodeset();
            for (unsigned long j = 0; j < singleSet->length(); ++ j)
                out->append(singleSet->item(j));
        }

        Expression::evaluationContext().node = saveCtx;
        return Value(out);
    } else {
        // ### what should happen in this case?
        Expression::reportInvalidExpressionErr();
        return Value();
    }
}

// kate: indent-width 4; replace-tabs off; tab-width 4; space-indent off;