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authorQt by Nokia <qt-info@nokia.com>2011-04-27 12:05:43 +0200
committeraxis <qt-info@nokia.com>2011-04-27 12:05:43 +0200
commite1b2c9deb5943faae2b29be6a5c006f75bb73f06 (patch)
treefc79e45367c0a8fc71185e9afc33f7503a58653c /src/xmlpatterns/expr/qforclause.cpp
downloadqtxmlpatterns-e1b2c9deb5943faae2b29be6a5c006f75bb73f06.tar.gz
Initial import from the monolithic Qt.
This is the beginning of revision history for this module. If you want to look at revision history older than this, please refer to the Qt Git wiki for how to use Git history grafting. At the time of writing, this wiki is located here: http://qt.gitorious.org/qt/pages/GitIntroductionWithQt If you have already performed the grafting and you don't see any history beyond this commit, try running "git log" with the "--follow" argument. Branched from the monolithic repo, Qt master branch, at commit 896db169ea224deb96c59ce8af800d019de63f12
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+/****************************************************************************
+**
+** Copyright (C) 2011 Nokia Corporation and/or its subsidiary(-ies).
+** All rights reserved.
+** Contact: Nokia Corporation (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 Technology Preview License Agreement accompanying
+** this package.
+**
+** 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 1.1, included in the file LGPL_EXCEPTION.txt in this package.
+**
+** If you have questions regarding the use of this file, please contact
+** Nokia at qt-info@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