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#include <QtDebug>

#include "qaxisstep_p.h"

#include "qcommonsequencetypes_p.h"

#include "qcommonvalues_p.h"

#include "qitemmappingiterator_p.h"

#include "qsequencemappingiterator_p.h"

#include "qpatternistlocale_p.h"

#include "qapplytemplate_p.h"

QT_BEGIN_NAMESPACE

using namespace QPatternist;

ApplyTemplate::ApplyTemplate(const TemplateMode::Ptr &mode,

                             const WithParam::Hash &withParams,

                             const TemplateMode::Ptr &defaultMode) : TemplateInvoker(withParams)

                                                                   , m_mode(mode)

                                                                   , m_defaultMode(defaultMode)

{

    Q_ASSERT_X(m_mode || m_defaultMode, Q_FUNC_INFO,

               "Either a mode, or the default mode must be supplied.");

}

Item ApplyTemplate::mapToItem(const QXmlNodeModelIndex &node,

                              const DynamicContext::Ptr &) const

{

    return Item(node);

}

Item::Iterator::Ptr ApplyTemplate::mapToSequence(const Item &item,

                                                 const DynamicContext::Ptr &context) const

{

    Q_UNUSED(item);

    return evaluateSequence(context);

}

TemplateMode::Ptr ApplyTemplate::effectiveMode(const DynamicContext::Ptr &context) const

{

    if(m_mode)

        return m_mode;

    else

    {

        const TemplateMode::Ptr currentMode(context->currentTemplateMode());

        if(currentMode)

            return currentMode;

        else

            return m_defaultMode;

    }

}

Template::Ptr ApplyTemplate::findTemplate(const DynamicContext::Ptr &context,

                                          const TemplateMode::Ptr &templateMode) const

{

    const int count = templateMode->templatePatterns.count();

    Template::Ptr result;

    /* It's redundant to initialize these values, but it suppresses false

     * positives with GCC. */

    PatternPriority priority = 0;

    TemplatePattern::ID id = -1;

    /* Possible optimization: detecting ambiguous rule matches could be forked off to a

     * low prioirity thread. */

    for(int i = 0; i < count; ++i)

    {

        const TemplatePattern::Ptr &candidate = templateMode->templatePatterns.at(i);

        if(candidate->matchPattern()->evaluateEBV(context))

        {

            if(result)

            {

                if(   candidate->id() != id

                   && candidate->priority() == priority

                   && candidate->templateTarget()->importPrecedence ==

                                                        result->importPrecedence)

                {

                    context->error(QtXmlPatterns::tr("Ambiguous rule match."),

                                   ReportContext::XTRE0540, this);

                }

                else

                    break;

            }

            else

            {

                result = candidate->templateTarget();

                priority = candidate->priority();

                id = candidate->id();

            }

        }

    }

    return result;

}

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

{

    const TemplateMode::Ptr templateMode(effectiveMode(context));

    const Template::Ptr &templateMatch = findTemplate(context, templateMode);

    if(templateMatch)

        return templateMatch->body->evaluateSequence(templateMatch->createContext(this, context, false));

    else

    {

        /* None of our templates matched. Proceed with a built-in. */

        const Item current(context->contextItem());

        // TODO it can be an atomic value?

        const QXmlNodeModelIndex::NodeKind kind(current.asNode().kind());

        if(kind == QXmlNodeModelIndex::Element || kind == QXmlNodeModelIndex::Document)

        {

            pDebug() << "No template match, using builtin template for element() | document-node()";

            const Item::Iterator::Ptr focusIterator(makeItemMappingIterator<Item>(ConstPtr(this),

                                                                                  current.asNode().iterate(QXmlNodeModelIndex::AxisChild),

                                                                                  context));

            const DynamicContext::Ptr focus(context->createFocus());

            focus->setFocusIterator(focusIterator);

            return makeSequenceMappingIterator<Item>(ConstPtr(this), focusIterator, focus);

        }

        return CommonValues::emptyIterator;

    }

}

Expression::Ptr ApplyTemplate::compress(const StaticContext::Ptr &context)

{

    /* If we have a mode, we will never need the default mode. */

    if(m_mode)

        m_defaultMode.reset();

    return TemplateInvoker::compress(context);

}

SequenceType::Ptr ApplyTemplate::staticType() const

{

    return CommonSequenceTypes::ZeroOrMoreItems;

}

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

{

    return visitor->visit(this);

}

Expression::Properties ApplyTemplate::properties() const

{

    return RequiresFocus | DisableElimination;

}

bool ApplyTemplate::configureRecursion(const CallTargetDescription::Ptr &sign)

{

    Q_ASSERT_X(false, Q_FUNC_INFO, "We're not expected to be called.");

    Q_UNUSED(sign);

    return false;

}

Expression::Ptr ApplyTemplate::body() const

{

    Q_ASSERT_X(false, Q_FUNC_INFO, "We're not expected to be called.");

    return Expression::Ptr();

}

CallTargetDescription::Ptr ApplyTemplate::callTargetDescription() const

{

    Q_ASSERT_X(false, Q_FUNC_INFO, "We're not expected to be called.");

    return CallTargetDescription::Ptr();

}

QT_END_NAMESPACE