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Diffstat (limited to 'src/xmlpatterns/expr/qforclause.cpp')
| -rw-r--r-- | src/xmlpatterns/expr/qforclause.cpp | 200 |
1 files changed, 200 insertions, 0 deletions
diff --git a/src/xmlpatterns/expr/qforclause.cpp b/src/xmlpatterns/expr/qforclause.cpp new file mode 100644 index 0000000..cf9e634 --- /dev/null +++ b/src/xmlpatterns/expr/qforclause.cpp @@ -0,0 +1,200 @@ +/**************************************************************************** +** +** Copyright (C) 2009 Nokia Corporation and/or its subsidiary(-ies). +** Contact: Qt Software Information (qt-info@nokia.com) +** +** This file is part of the QtXmlPatterns module of the Qt Toolkit. +** +** $QT_BEGIN_LICENSE:LGPL$ +** No Commercial Usage +** This file contains pre-release code and may not be distributed. +** You may use this file in accordance with the terms and conditions +** contained in the either Technology Preview License Agreement or the +** Beta Release License Agreement. +** +** GNU Lesser General Public License Usage +** Alternatively, this file may be used under the terms of the GNU Lesser +** General Public License version 2.1 as published by the Free Software +** Foundation and appearing in the file LICENSE.LGPL included in the +** packaging of this file. Please review the following information to +** ensure the GNU Lesser General Public License version 2.1 requirements +** will be met: http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html. +** +** In addition, as a special exception, Nokia gives you certain +** additional rights. These rights are described in the Nokia Qt LGPL +** Exception version 1.0, included in the file LGPL_EXCEPTION.txt in this +** package. +** +** GNU General Public License Usage +** Alternatively, this file may be used under the terms of the GNU +** General Public License version 3.0 as published by the Free Software +** Foundation and appearing in the file LICENSE.GPL included in the +** packaging of this file. Please review the following information to +** ensure the GNU General Public License version 3.0 requirements will be +** met: http://www.gnu.org/copyleft/gpl.html. +** +** If you are unsure which license is appropriate for your use, please +** contact the sales department at qt-sales@nokia.com. +** $QT_END_LICENSE$ +** +****************************************************************************/ + +#include "qcommonsequencetypes_p.h" +#include "qemptysequence_p.h" +#include "qgenericsequencetype_p.h" +#include "qitemmappingiterator_p.h" +#include "qoptimizationpasses_p.h" +#include "qsequencemappingiterator_p.h" + +#include "qforclause_p.h" + +QT_BEGIN_NAMESPACE + +using namespace QPatternist; + +ForClause::ForClause(const VariableSlotID varSlot, + const Expression::Ptr &bindingSequence, + const Expression::Ptr &returnExpression, + const VariableSlotID positionSlot) : PairContainer(bindingSequence, returnExpression), + m_varSlot(varSlot), + m_positionSlot(positionSlot), + m_allowsMany(true) +{ + Q_ASSERT(m_positionSlot > -2); +} + +Item ForClause::mapToItem(const Item &item, + const DynamicContext::Ptr &context) const +{ + context->setRangeVariable(m_varSlot, item); + return m_operand2->evaluateSingleton(context); +} + +Item::Iterator::Ptr ForClause::mapToSequence(const Item &item, + const DynamicContext::Ptr &context) const +{ + context->setRangeVariable(m_varSlot, item); + return m_operand2->evaluateSequence(context); +} + +void ForClause::riggPositionalVariable(const DynamicContext::Ptr &context, + const Item::Iterator::Ptr &source) const +{ + if(m_positionSlot > -1) + context->setPositionIterator(m_positionSlot, source); +} + +Item::Iterator::Ptr ForClause::evaluateSequence(const DynamicContext::Ptr &context) const +{ + const Item::Iterator::Ptr source(m_operand1->evaluateSequence(context)); + + riggPositionalVariable(context, source); + + if(m_allowsMany) + { + return makeSequenceMappingIterator<Item>(ConstPtr(this), + source, + context); + } + else + { + return makeItemMappingIterator<Item>(ConstPtr(this), + source, + context); + } +} + +Item ForClause::evaluateSingleton(const DynamicContext::Ptr &context) const +{ + return evaluateSequence(context)->next(); +} + +void ForClause::evaluateToSequenceReceiver(const DynamicContext::Ptr &context) const +{ + Item::Iterator::Ptr it; + const Item::Iterator::Ptr source(m_operand1->evaluateSequence(context)); + + riggPositionalVariable(context, source); + + Item next(source->next()); + + while(next) + { + context->setRangeVariable(m_varSlot, next); + m_operand2->evaluateToSequenceReceiver(context); + next = source->next(); + } +} + +Expression::Ptr ForClause::typeCheck(const StaticContext::Ptr &context, + const SequenceType::Ptr &reqType) +{ + const Expression::Ptr me(PairContainer::typeCheck(context, reqType)); + const Cardinality card(m_operand1->staticType()->cardinality()); + + /* If our source is empty we will always evaluate to the empty sequence, so rewrite. */ + if(card.isEmpty()) + return EmptySequence::create(this, context); + else + return me; + + /* This breaks because the variable references haven't rewritten themselves, so + * they dangle. When this is fixed, evaluateSingleton can be removed. */ + /* + else if(card->allowsMany()) + return me; + else + return m_operand2; + */ +} + +Expression::Ptr ForClause::compress(const StaticContext::Ptr &context) +{ + const Expression::Ptr me(PairContainer::compress(context)); + if(me != this) + return me; + + /* This is done after calling PairContainer::typeCheck(). The advantage of this is that + * m_allowsMany is updated according to what the operand says after it has compressed. However, + * if it was initialized to false(as it once was..), ForClause::evaluateSequence() + * would potentially have been called by PairContainer::compress(), and it would have + * used an unsafe branch. */ + m_allowsMany = m_operand2->staticType()->cardinality().allowsMany(); + + return me; +} + +SequenceType::Ptr ForClause::staticType() const +{ + const SequenceType::Ptr returnType(m_operand2->staticType()); + + return makeGenericSequenceType(returnType->itemType(), + m_operand1->staticType()->cardinality() + * /* multiply operator */ + returnType->cardinality()); +} + +SequenceType::List ForClause::expectedOperandTypes() const +{ + SequenceType::List result; + result.append(CommonSequenceTypes::ZeroOrMoreItems); + result.append(CommonSequenceTypes::ZeroOrMoreItems); + return result; +} + +ExpressionVisitorResult::Ptr ForClause::accept(const ExpressionVisitor::Ptr &visitor) const +{ + return visitor->visit(this); +} + +OptimizationPass::List ForClause::optimizationPasses() const +{ + return OptimizationPasses::forPasses; +} + +Expression::ID ForClause::id() const +{ + return IDForClause; +} + +QT_END_NAMESPACE |