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Diffstat (limited to 'src/xmlpatterns/expr/qexpressionsequence.cpp')
| -rw-r--r-- | src/xmlpatterns/expr/qexpressionsequence.cpp | 206 |
1 files changed, 206 insertions, 0 deletions
diff --git a/src/xmlpatterns/expr/qexpressionsequence.cpp b/src/xmlpatterns/expr/qexpressionsequence.cpp new file mode 100644 index 0000000..d052400 --- /dev/null +++ b/src/xmlpatterns/expr/qexpressionsequence.cpp @@ -0,0 +1,206 @@ +/**************************************************************************** +** +** 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 "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 |