/****************************************************************************

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** This file is part of the QtXmlPatterns module of the Qt Toolkit.

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****************************************************************************/

#include "qbuiltintypes_p.h"

#include "qcommonsequencetypes_p.h"

#include "qitemmappingiterator_p.h"

#include "qgenericsequencetype_p.h"

#include "qparentnodeaxis_p.h"

#include "qaxisstep_p.h"

QT_BEGIN_NAMESPACE

using namespace QPatternist;

namespace QPatternist

{

    /**

     * This operator is needed for the s_whenAxisNodeKindEmpty array. The @c int constructors

     * ensure we invoke another operator| such that we don't get an infinite loop.

     */

    static inline QXmlNodeModelIndex::NodeKind operator|(const QXmlNodeModelIndex::NodeKind &op1, const QXmlNodeModelIndex::NodeKind &op2)

    {

        return QXmlNodeModelIndex::NodeKind(int(op1) | int(op2));

    }

}

/**

 * @note The order is significant. It is of the same order as the values in QXmlNodeModelIndex::Axis is declared.

 */

const QXmlNodeModelIndex::NodeKind AxisStep::s_whenAxisNodeKindEmpty[] =

{

    QXmlNodeModelIndex::Attribute|QXmlNodeModelIndex::Text|QXmlNodeModelIndex::ProcessingInstruction|QXmlNodeModelIndex::Comment|QXmlNodeModelIndex::Namespace,   // child;

    QXmlNodeModelIndex::Attribute|QXmlNodeModelIndex::Text|QXmlNodeModelIndex::ProcessingInstruction|QXmlNodeModelIndex::Comment|QXmlNodeModelIndex::Namespace,   // descendant;

    QXmlNodeModelIndex::Document|QXmlNodeModelIndex::Attribute|QXmlNodeModelIndex::Text|QXmlNodeModelIndex::ProcessingInstruction|QXmlNodeModelIndex::Comment|QXmlNodeModelIndex::Namespace,// attribute;

    QXmlNodeModelIndex::NodeKind(0),                         // self;

    QXmlNodeModelIndex::NodeKind(0),                         // descendant-or-self;

    QXmlNodeModelIndex::Document|QXmlNodeModelIndex::Attribute|QXmlNodeModelIndex::Text|QXmlNodeModelIndex::ProcessingInstruction|QXmlNodeModelIndex::Comment|QXmlNodeModelIndex::Namespace,    // namespace;

    QXmlNodeModelIndex::Document,                                         // following;

    QXmlNodeModelIndex::Document,                                         // parent;

    QXmlNodeModelIndex::Document,                                         // ancestor

    QXmlNodeModelIndex::Document|QXmlNodeModelIndex::Attribute|QXmlNodeModelIndex::Namespace,         // preceding-sibling;

    QXmlNodeModelIndex::Document|QXmlNodeModelIndex::Attribute|QXmlNodeModelIndex::Namespace,         // following-sibling;

    QXmlNodeModelIndex::Document,                                         // preceding;

    QXmlNodeModelIndex::NodeKind(0)                          // ancestor-or-self;

};

bool AxisStep::isAlwaysEmpty(const QXmlNodeModelIndex::Axis axis, const QXmlNodeModelIndex::NodeKind nodeKind)

{

    return (s_whenAxisNodeKindEmpty[(1 >> axis) - 1] & nodeKind) != 0;

}

AxisStep::AxisStep(const QXmlNodeModelIndex::Axis a,

                   const ItemType::Ptr &nt) : m_axis(a),

                                              m_nodeTest(nt)

{

    Q_ASSERT(m_nodeTest);

    Q_ASSERT_X(BuiltinTypes::node->xdtTypeMatches(m_nodeTest), Q_FUNC_INFO,

               "We assume we're a node type.");

}

Item AxisStep::mapToItem(const QXmlNodeModelIndex &node,

                         const DynamicContext::Ptr &context) const

{

    Q_ASSERT(!node.isNull());

    Q_ASSERT(Item(node).isNode());

    Q_ASSERT(Item(node));

    Q_UNUSED(context);

    if(m_nodeTest->itemMatches(Item(node)))

        return Item(node);

    else

        return Item();

}

Item::Iterator::Ptr AxisStep::evaluateSequence(const DynamicContext::Ptr &context) const

{

    /* If we don't have a focus, it's either a bug or our parent isn't a Path

     * that have advanced the focus iterator. Hence, attempt to advance the focus on our own. */

    if(!context->contextItem())

        context->focusIterator()->next();

    Q_ASSERT(context->contextItem());

    const QXmlNodeModelIndex::Iterator::Ptr source(context->contextItem().asNode().iterate(m_axis));

    return makeItemMappingIterator<Item>(ConstPtr(this), source, context);

}

Item AxisStep::evaluateSingleton(const DynamicContext::Ptr &context) const

{

    /* If we don't have a focus, it's either a bug or our parent isn't a Path

     * that have advanced the focus iterator. Hence, attempt to advance the focus on our own. */

    if(!context->contextItem())

        context->focusIterator()->next();

    Q_ASSERT(context->contextItem());

    const QXmlNodeModelIndex::Iterator::Ptr it(context->contextItem().asNode().iterate(m_axis));

    QXmlNodeModelIndex next(it->next());

    while(!next.isNull())

    {

        const Item candidate(mapToItem(next, context));

        if(candidate)

            return candidate;

        else

            next = it->next();

    };

    return Item();

}

Expression::Ptr AxisStep::typeCheck(const StaticContext::Ptr &context,

                                    const SequenceType::Ptr &reqType)

{

    if(m_axis == QXmlNodeModelIndex::AxisParent && *m_nodeTest == *BuiltinTypes::node)

    {

        /* We only rewrite parent::node() to ParentNodeAxis. */

        return rewrite(Expression::Ptr(new ParentNodeAxis()), context)->typeCheck(context, reqType);

    }

    /* TODO temporarily disabled

    else if(isAlwaysEmpty(m_axis, static_cast<const AnyNodeType *>(m_nodeTest.data())->nodeKind()))

        return EmptySequence::create(this, context);

        */

    else

        return EmptyContainer::typeCheck(context, reqType);

}

SequenceType::Ptr AxisStep::staticType() const

{

    Cardinality cardinality;

    if(m_axis == QXmlNodeModelIndex::AxisSelf || m_axis == QXmlNodeModelIndex::AxisParent)

        cardinality = Cardinality::zeroOrOne();

    else

        cardinality = Cardinality::zeroOrMore();

    return makeGenericSequenceType(m_nodeTest,

                                   cardinality);

}

SequenceType::List AxisStep::expectedOperandTypes() const

{

    SequenceType::List result;

    result.append(CommonSequenceTypes::ZeroOrMoreNodes);

    return result;

}

Expression::Properties AxisStep::properties() const

{

    return RequiresContextItem | DisableElimination;

}

ItemType::Ptr AxisStep::expectedContextItemType() const

{

    return BuiltinTypes::node;

}

ExpressionVisitorResult::Ptr AxisStep::accept(const ExpressionVisitor::Ptr &visitor) const

{

    return visitor->visit(this);

}

QXmlNodeModelIndex::Axis AxisStep::axis() const

{

    return m_axis;

}

QString AxisStep::axisName(const QXmlNodeModelIndex::Axis axis)

{

    const char *result = 0;

    switch(axis)

    {

        /* These must not be translated. */

        case QXmlNodeModelIndex::AxisAncestorOrSelf:    result = "ancestor-or-self";    break;

        case QXmlNodeModelIndex::AxisAncestor:          result = "ancestor";            break;

        case QXmlNodeModelIndex::AxisAttributeOrTop:    result = "attribute-or-top";    break;

        case QXmlNodeModelIndex::AxisAttribute:         result = "attribute";           break;

        case QXmlNodeModelIndex::AxisChildOrTop:        result = "child-or-top";        break;

        case QXmlNodeModelIndex::AxisChild:             result = "child";               break;

        case QXmlNodeModelIndex::AxisDescendantOrSelf:  result = "descendant-or-self";  break;

        case QXmlNodeModelIndex::AxisDescendant:        result = "descendant";          break;

        case QXmlNodeModelIndex::AxisFollowing:         result = "following";           break;

        case QXmlNodeModelIndex::AxisFollowingSibling:  result = "following-sibling";   break;

        case QXmlNodeModelIndex::AxisNamespace:         result = "namespace";           break;

        case QXmlNodeModelIndex::AxisParent:            result = "parent";              break;

        case QXmlNodeModelIndex::AxisPreceding:         result = "preceding";           break;

        case QXmlNodeModelIndex::AxisPrecedingSibling:  result = "preceding-sibling";   break;

        case QXmlNodeModelIndex::AxisSelf:              result = "self";                break;

    }

    Q_ASSERT_X(result, Q_FUNC_INFO, "An unknown axis type was apparently encountered.");

    return QString::fromLatin1(result);

}

PatternPriority AxisStep::patternPriority() const

{

    return static_cast<const AnyNodeType *>(m_nodeTest.data())->patternPriority();

}

Expression::ID AxisStep::id() const

{

    return IDAxisStep;

}

QT_END_NAMESPACE