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| |
| #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 |