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Diffstat (limited to 'src/xmlpatterns/expr/qletclause.cpp')
| -rw-r--r-- | src/xmlpatterns/expr/qletclause.cpp | 142 |
1 files changed, 142 insertions, 0 deletions
diff --git a/src/xmlpatterns/expr/qletclause.cpp b/src/xmlpatterns/expr/qletclause.cpp new file mode 100644 index 0000000..d3e939b --- /dev/null +++ b/src/xmlpatterns/expr/qletclause.cpp @@ -0,0 +1,142 @@ +/**************************************************************************** +** +** 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 "qboolean_p.h" +#include "qcommonsequencetypes_p.h" +#include "qdynamiccontextstore_p.h" +#include "qliteral_p.h" + +#include "qletclause_p.h" + +QT_BEGIN_NAMESPACE + +using namespace QPatternist; + +LetClause::LetClause(const Expression::Ptr &operand1, + const Expression::Ptr &operand2, + const VariableDeclaration::Ptr &decl) : PairContainer(operand1, operand2) + , m_varDecl(decl) +{ + Q_ASSERT(m_varDecl); +} + +DynamicContext::Ptr LetClause::bindVariable(const DynamicContext::Ptr &context) const +{ + context->setExpressionVariable(m_varDecl->slot, Expression::Ptr(new DynamicContextStore(m_operand1, context))); + return context; +} + +Item::Iterator::Ptr LetClause::evaluateSequence(const DynamicContext::Ptr &context) const +{ + return m_operand2->evaluateSequence(bindVariable(context)); +} + +Item LetClause::evaluateSingleton(const DynamicContext::Ptr &context) const +{ + return m_operand2->evaluateSingleton(bindVariable(context)); +} + +bool LetClause::evaluateEBV(const DynamicContext::Ptr &context) const +{ + return m_operand2->evaluateEBV(bindVariable(context)); +} + +void LetClause::evaluateToSequenceReceiver(const DynamicContext::Ptr &context) const +{ + m_operand2->evaluateToSequenceReceiver(bindVariable(context)); +} + +Expression::Ptr LetClause::typeCheck(const StaticContext::Ptr &context, + const SequenceType::Ptr &reqType) +{ + /* Consider the following query: + * + * <tt>let $d := \<child type=""/> + * return $d//\*[let $i := @type + * return $d//\*[$i]]</tt> + * + * The node test <tt>@type</tt> is referenced from two different places, + * where each reference have a different focus. So, in the case of that the source + * uses the focus, we need to use a DynamicContextStore to ensure the variable + * is always evaluated with the correct focus, regardless of where it is referenced + * from. + * + * We miss out a lot of false positives. For instance, the case of where the focus + * is identical for everyone. One reason we cannot check this, is that Expression + * doesn't know about its parent. + */ + m_varDecl->canSourceRewrite = !m_operand1->deepProperties().testFlag(RequiresFocus); + + if(m_varDecl->canSourceRewrite) + return m_operand2->typeCheck(context, reqType); + else + return PairContainer::typeCheck(context, reqType); +} + +Expression::Properties LetClause::properties() const +{ + return m_varDecl->expression()->properties() & (Expression::RequiresFocus | Expression::IsEvaluated | Expression::DisableElimination); +} + +SequenceType::List LetClause::expectedOperandTypes() const +{ + SequenceType::List result; + result.append(CommonSequenceTypes::ZeroOrMoreItems); + result.append(CommonSequenceTypes::ZeroOrMoreItems); + return result; +} + +SequenceType::Ptr LetClause::staticType() const +{ + return m_operand2->staticType(); +} + +ExpressionVisitorResult::Ptr LetClause::accept(const ExpressionVisitor::Ptr &visitor) const +{ + return visitor->visit(this); +} + +Expression::ID LetClause::id() const +{ + return IDLetClause; +} + +QT_END_NAMESPACE |