/****************************************************************************+
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**+
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** Copyright (C) 2010 Nokia Corporation and/or its subsidiary(-ies).+
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** All rights reserved.+
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** Contact: Nokia Corporation (qt-info@nokia.com)+
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**+
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** This file is part of the QtXmlPatterns module of the Qt Toolkit.+
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**+
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** $QT_BEGIN_LICENSE:LGPL$+
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** No Commercial Usage+
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** This file contains pre-release code and may not be distributed.+
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** You may use this file in accordance with the terms and conditions+
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** contained in the Technology Preview License Agreement accompanying+
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** this package.+
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**+
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** GNU Lesser General Public License Usage+
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** Alternatively, this file may be used under the terms of the GNU Lesser+
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** General Public License version 2.1 as published by the Free Software+
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** Foundation and appearing in the file LICENSE.LGPL included in the+
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** packaging of this file.  Please review the following information to+
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** ensure the GNU Lesser General Public License version 2.1 requirements+
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** will be met: http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.+
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**+
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** In addition, as a special exception, Nokia gives you certain additional+
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** rights.  These rights are described in the Nokia Qt LGPL Exception+
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** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.+
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**+
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** If you have questions regarding the use of this file, please contact+
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** Nokia at qt-info@nokia.com.+
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**+
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**+
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**+
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**+
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**+
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**+
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**+
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**+
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** $QT_END_LICENSE$+
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**+
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****************************************************************************/+
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+
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#include "qcommonsequencetypes_p.h"+
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#include "qemptysequence_p.h"+
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#include "qgenericsequencetype_p.h"+
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#include "qitemmappingiterator_p.h"+
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#include "qoptimizationpasses_p.h"+
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#include "qsequencemappingiterator_p.h"+
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+
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#include "qforclause_p.h"+
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+
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QT_BEGIN_NAMESPACE+
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+
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using namespace QPatternist;+
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+
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ForClause::ForClause(const VariableSlotID varSlot,+
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                     const Expression::Ptr &bindingSequence,+
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                     const Expression::Ptr &returnExpression,+
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                     const VariableSlotID positionSlot) : PairContainer(bindingSequence, returnExpression),+
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                                                          m_varSlot(varSlot),+
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                                                          m_positionSlot(positionSlot),+
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                                                          m_allowsMany(true)+
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{+
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    Q_ASSERT(m_positionSlot > -2);+
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}+
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+
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Item ForClause::mapToItem(const Item &item,+
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                          const DynamicContext::Ptr &context) const+
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{+
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    context->setRangeVariable(m_varSlot, item);+
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    return m_operand2->evaluateSingleton(context);+
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}+
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+
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Item::Iterator::Ptr ForClause::mapToSequence(const Item &item,+
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                                             const DynamicContext::Ptr &context) const+
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{+
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    context->setRangeVariable(m_varSlot, item);+
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    return m_operand2->evaluateSequence(context);+
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}+
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+
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void ForClause::riggPositionalVariable(const DynamicContext::Ptr &context,+
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                                       const Item::Iterator::Ptr &source) const+
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{+
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    if(m_positionSlot > -1)+
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        context->setPositionIterator(m_positionSlot, source);+
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}+
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+
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Item::Iterator::Ptr ForClause::evaluateSequence(const DynamicContext::Ptr &context) const+
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{+
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    const Item::Iterator::Ptr source(m_operand1->evaluateSequence(context));+
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+
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    riggPositionalVariable(context, source);+
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+
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    if(m_allowsMany)+
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    {+
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        return makeSequenceMappingIterator<Item>(ConstPtr(this),+
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                                                 source,+
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                                                 context);+
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    }+
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    else+
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    {+
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        return makeItemMappingIterator<Item>(ConstPtr(this),+
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                                             source,+
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                                             context);+
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    }+
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}+
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+
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Item ForClause::evaluateSingleton(const DynamicContext::Ptr &context) const+
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{+
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    return evaluateSequence(context)->next();+
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}+
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+
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void ForClause::evaluateToSequenceReceiver(const DynamicContext::Ptr &context) const+
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{+
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    Item::Iterator::Ptr it;+
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    const Item::Iterator::Ptr source(m_operand1->evaluateSequence(context));+
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+
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    riggPositionalVariable(context, source);+
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+
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    Item next(source->next());+
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+
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    while(next)+
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    {+
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        context->setRangeVariable(m_varSlot, next);+
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        m_operand2->evaluateToSequenceReceiver(context);+
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        next = source->next();+
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    }+
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}+
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+
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Expression::Ptr ForClause::typeCheck(const StaticContext::Ptr &context,+
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                                     const SequenceType::Ptr &reqType)+
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{+
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    const Expression::Ptr me(PairContainer::typeCheck(context, reqType));+
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    const Cardinality card(m_operand1->staticType()->cardinality());+
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+
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    /* If our source is empty we will always evaluate to the empty sequence, so rewrite. */+
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    if(card.isEmpty())+
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        return EmptySequence::create(this, context);+
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    else+
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        return me;+
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+
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    /* This breaks because  the variable references haven't rewritten themselves, so+
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     * they dangle. When this is fixed, evaluateSingleton can be removed. */+
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    /*+
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    else if(card->allowsMany())+
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        return me;+
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    else+
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        return m_operand2;+
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        */+
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}+
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+
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Expression::Ptr ForClause::compress(const StaticContext::Ptr &context)+
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{+
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    const Expression::Ptr me(PairContainer::compress(context));+
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    if(me != this)+
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        return me;+
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+
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    /* This is done after calling PairContainer::typeCheck(). The advantage of this is that+
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     * m_allowsMany is updated according to what the operand says after it has compressed. However,+
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     * if it was initialized to false(as it once was..), ForClause::evaluateSequence()+
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     * would potentially have been called by PairContainer::compress(), and it would have+
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     * used an unsafe branch. */+
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    m_allowsMany = m_operand2->staticType()->cardinality().allowsMany();+
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+
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    return me;+
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}+
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+
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SequenceType::Ptr ForClause::staticType() const+
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{+
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    const SequenceType::Ptr returnType(m_operand2->staticType());+
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+
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    return makeGenericSequenceType(returnType->itemType(),+
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                                   m_operand1->staticType()->cardinality()+
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                                        * /* multiply operator */+
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                                   returnType->cardinality());+
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}+
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+
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SequenceType::List ForClause::expectedOperandTypes() const+
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{+
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    SequenceType::List result;+
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    result.append(CommonSequenceTypes::ZeroOrMoreItems);+
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    result.append(CommonSequenceTypes::ZeroOrMoreItems);+
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    return result;+
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}+
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+
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ExpressionVisitorResult::Ptr ForClause::accept(const ExpressionVisitor::Ptr &visitor) const+
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{+
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    return visitor->visit(this);+
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}+
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+
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OptimizationPass::List ForClause::optimizationPasses() const+
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{+
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    return OptimizationPasses::forPasses;+
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}+
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+
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Expression::ID ForClause::id() const+
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{+
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    return IDForClause;+
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}+
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+
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QT_END_NAMESPACE+
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