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#include "qcardinalityverifier_p.h"

#include "qcommonsequencetypes_p.h"

#include "qemptysequence_p.h"

#include "qsequencemappingiterator_p.h"

#include "qexpressionsequence_p.h"

QT_BEGIN_NAMESPACE

using namespace QPatternist;

ExpressionSequence::ExpressionSequence(const Expression::List &ops) : UnlimitedContainer(ops)

{

    Q_ASSERT_X(1 < ops.count(), Q_FUNC_INFO,

               "It makes no sense to have an ExpressionSequence containing less than two expressions.");

}

Item::Iterator::Ptr ExpressionSequence::mapToSequence(const Expression::Ptr &expr,

                                                      const DynamicContext::Ptr &context) const

{

    return expr->evaluateSequence(context);

}

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

{

    return makeSequenceMappingIterator<Item>(ConstPtr(this),

                                             makeListIterator(m_operands),

                                             context);

}

void ExpressionSequence::evaluateToSequenceReceiver(const DynamicContext::Ptr &context) const

{

    Expression::List::const_iterator it(m_operands.constBegin());

    const Expression::List::const_iterator end(m_operands.constEnd());

    Expression::List result;

    for(; it != end; ++it)

        (*it)->evaluateToSequenceReceiver(context);

}

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

{

    const Expression::Ptr me(UnlimitedContainer::compress(context));

    if(me != this)

        return me;

    Expression::List::const_iterator it(m_operands.constBegin());

    const Expression::List::const_iterator end(m_operands.constEnd());

    Expression::List result;

    for(; it != end; ++it)

    {

        const ID Id = (*it)->id();

        /* Remove empty sequences. This is rather important because we have some steps in the parser that

         * intentionally, unconditionally and for temporary reasons create expressions like (expr, ()). Of course,

         * empty sequences also occur as part of optimizations.

         *

         * User function call sites that are of type empty-sequence() must be avoided since

         * they may contain calls to fn:error(), which we would rewrite away otherwise. */

        if(Id != IDUserFunctionCallsite && (*it)->staticType()->cardinality().isEmpty())

        {

            /* Rewrite "(1, (), 2)" into "(1, 2)" by not

             * adding (*it) to result. */

            continue;

        }

        else if(Id == IDExpressionSequence)

        {

            /* Rewrite "(1, (2, 3), 4)" into "(1, 2, 3, 4)" */

            Expression::List::const_iterator seqIt((*it)->operands().constBegin());

            const Expression::List::const_iterator seqEnd((*it)->operands().constEnd());

            for(; seqIt != seqEnd; ++seqIt)

                result.append(*seqIt);

        }

        else

            result.append(*it);

    }

    if(result.isEmpty())

        return EmptySequence::create(this, context);

    else if(result.count() == 1)

        return result.first();

    else

    {

        m_operands = result;

        return me;

    }

}

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

                                              const SequenceType::Ptr &reqType)

{

    Q_ASSERT(reqType);

    Expression::List::iterator it(m_operands.begin());

    const Expression::List::iterator end(m_operands.end());

    /* We treat the cardinality differently here by allowing the empty sequence

     * for each individual Expression, since the Cardinality can be conformed to by

     * the ExpressionSequence as a whole(which we check for at the end). */

    const SequenceType::Ptr testOnlyIT(makeGenericSequenceType(reqType->itemType(),

                                                               Cardinality::empty() |

                                                               reqType->cardinality()));

    for(; it != end; ++it)

        *it = (*it)->typeCheck(context, testOnlyIT);

    /* The above loop is only guaranteed to find item type errors, but the cardinality

     * can still be wrong since the operands were treated individually. */

    return CardinalityVerifier::verifyCardinality(Expression::Ptr(this), reqType->cardinality(), context);

}

Expression::Properties ExpressionSequence::properties() const

{

    const Expression::List::const_iterator end(m_operands.constEnd());

    Expression::List::const_iterator it;

    bool allEvaled = true;

    Expression::Properties props(DisableElimination); /* Why do we have this flag? */

    for(it = m_operands.constBegin(); it != end; ++it)

    {

        const Expression::Properties newp((*it)->properties());

        props |= newp;

        if((newp & IsEvaluated) != IsEvaluated)

        {

            allEvaled = false;

            break;

        }

    }

    if(!allEvaled)

        props &= ~IsEvaluated; /* Remove IsEvaluated. */

    /* One of our children might need the focus, but we don't, so

     * cut it out. */

    return props & ~RequiresFocus;

}

SequenceType::Ptr ExpressionSequence::staticType() const

{

    return operandsUnionType<ProductOfCardinality>();

}

SequenceType::List ExpressionSequence::expectedOperandTypes() const

{

    SequenceType::List result;

    /* ExpressionSequence is a bit strange type wise since it has an

     * infinite amount of operands. */

    result.append(CommonSequenceTypes::ZeroOrMoreItems);

    return result;

}

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

{

    return visitor->visit(this);

}

Expression::ID ExpressionSequence::id() const

{

    return IDExpressionSequence;

}

QT_END_NAMESPACE