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| ** This file is part of the QtXmlPatterns module of the Qt Toolkit. |
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| |
| #include "qcardinalityverifier_p.h" |
| #include "qcommonsequencetypes_p.h" |
| #include "qemptysequence_p.h" |
| #include "qabstractxmlforwarditerator_p.h" |
| #include "qliteral_p.h" |
| #include "qsequencemappingiterator_p.h" |
| |
| #include "qexpressionsequence_p.h" |
| |
| #include <algorithm> |
| #include <iterator> |
| |
| 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)" */ |
| const auto &operands = (*it)->operands(); |
| std::copy(operands.cbegin(), operands.cend(), std::back_inserter(result)); |
| } else if (Id == IDLiteralSequence) { |
| /* Rewrite "(1, (2, 3), 4)" into "(1, 2, 3, 4)" */ |
| // Note: LiteralSequence does not use the dynamic context, so we pass in a nullptr. |
| Item::Iterator::Ptr seqIt = (*it)->evaluateSequence(DynamicContext::Ptr(nullptr)); |
| |
| while (!seqIt->next().isNull()) |
| result.append(Literal::Ptr(new Literal(seqIt->current()))); |
| } |
| 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 |
