| /**************************************************************************** |
| ** |
| ** Copyright (C) 2016 The Qt Company Ltd. |
| ** Contact: https://www.qt.io/licensing/ |
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| ** This file is part of the QtXmlPatterns module of the Qt Toolkit. |
| ** |
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| ** Alternatively, this file may be used under the terms of the GNU |
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| ** Public license version 3 or any later version approved by the KDE Free |
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| ****************************************************************************/ |
| |
| #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, m_operand1); |
| 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 |