source: trunk/src/xmlpatterns/expr/qcopyof.cpp@ 674

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#include "qbuiltintypes_p.h"
#include "qcommonsequencetypes_p.h"
#include "qitemmappingiterator_p.h"

#include "qcopyof_p.h"

QT_BEGIN_NAMESPACE

using namespace QPatternist;

CopyOf::CopyOf(const Expression::Ptr &operand,
               const bool inheritNSS,
               const bool preserveNSS) : SingleContainer(operand)
                                       , m_inheritNamespaces(inheritNSS)
                                       , m_preserveNamespaces(preserveNSS)
                                       , m_settings((m_inheritNamespaces ? QAbstractXmlNodeModel::InheritNamespaces : QAbstractXmlNodeModel::NodeCopySettings()) |
                                                    (m_preserveNamespaces ? QAbstractXmlNodeModel::PreserveNamespaces : QAbstractXmlNodeModel::NodeCopySettings()))
{
}

Expression::Ptr CopyOf::compress(const StaticContext::Ptr &context)
{
    /* We have zero effect if we have these settings. */
    if(m_inheritNamespaces && m_preserveNamespaces)
        return m_operand->compress(context);
    else
    {
        const ItemType::Ptr t(m_operand->staticType()->itemType());
        /* We have no effect on the empty sequence or atomic values. */
        if(BuiltinTypes::xsAnyAtomicType->xdtTypeMatches(t)
          || *t == *CommonSequenceTypes::Empty)
            return m_operand->compress(context);
        else
            return SingleContainer::compress(context);
    }
}

void CopyOf::evaluateToSequenceReceiver(const DynamicContext::Ptr &context) const
{
    /* Optimization: this completely breaks streaming. We get a call to
     * evaluateToSequenceReceiver() but we require heap allocations by calling
     * evaluateSequence(). */

    const Item::Iterator::Ptr it(m_operand->evaluateSequence(context));
    QAbstractXmlReceiver *const receiver = context->outputReceiver();
    Item next(it->next());

    while(next)
    {
        if(next.isNode())
        {
            const QXmlNodeModelIndex &asNode = next.asNode();
            asNode.model()->copyNodeTo(asNode, receiver, m_settings);
        }
        else
            receiver->item(next);

        next = it->next();
    }
}

ExpressionVisitorResult::Ptr CopyOf::accept(const ExpressionVisitor::Ptr &visitor) const
{
    return visitor->visit(this);
}

SequenceType::Ptr CopyOf::staticType() const
{
    return m_operand->staticType();
}

SequenceType::List CopyOf::expectedOperandTypes() const
{
    SequenceType::List result;
    result.append(CommonSequenceTypes::ZeroOrMoreItems);
    return result;
}

Expression::Properties CopyOf::properties() const
{
    /* We have the content of node constructors as children, but even though
     * createCopyOf() typically avoids creating us, we can still end up with an operand
     * that allows compression. We must always avoid that, because we don't have
     * implementation of evaluateSequence(), and so on. */
    return (m_operand->properties() & ~CreatesFocusForLast) | DisableElimination;
}

ItemType::Ptr CopyOf::expectedContextItemType() const
{
    return m_operand->expectedContextItemType();
}

QT_END_NAMESPACE