Verifies that the sequence an Expression evaluates to conforms to a Cardinality. More...

#include <qcardinalityverifier_p.h>

Inheritance diagram for QPatternist::CardinalityVerifier:

Public Functions
virtual ExpressionVisitorResult::Ptr	accept (const ExpressionVisitor::Ptr &visitor) const

virtual const SourceLocationReflection *	actualReflection () const
	Returns `this`. More...

	CardinalityVerifier (const Expression::Ptr &operand, const Cardinality &card, const ReportContext::ErrorCode code)

virtual Expression::Ptr	compress (const StaticContext::Ptr &context)

virtual Item::Iterator::Ptr	evaluateSequence (const DynamicContext::Ptr &context) const

virtual Item	evaluateSingleton (const DynamicContext::Ptr &) const

virtual SequenceType::List	expectedOperandTypes () const

ID	id () const

virtual SequenceType::Ptr	staticType () const

Public Functions inherited from QPatternist::SingleContainer
virtual bool	compressOperands (const StaticContext::Ptr &)

virtual Expression::List	operands () const

virtual void	setOperands (const Expression::List &operands)

Public Functions inherited from QPatternist::Expression
virtual void	announceFocusType (const ItemType::Ptr &itemType)

Properties	deepProperties () const
	Computes the union of properties for this Expression and all its descending children. More...

virtual Properties	dependencies () const

virtual QString	description () const

virtual bool	evaluateEBV (const DynamicContext::Ptr &context) const

virtual void	evaluateToSequenceReceiver (const DynamicContext::Ptr &context) const

virtual ItemType::Ptr	expectedContextItemType () const

	Expression ()

bool	has (const Property prop) const

bool	hasDependency (const Property prop) const

bool	is (const ID id) const

bool	isEvaluated () const

virtual ItemType::Ptr	newFocusType () const

virtual QList< QExplicitlySharedDataPointer< OptimizationPass > >	optimizationPasses () const

virtual PatternPriority	patternPriority () const

virtual Properties	properties () const

const Expression::Ptr &	rewrite (const Expression::Ptr &to, const StaticContext::Ptr &context) const
	Rewrites this Expression to `to`, and return `to`. More...

virtual Expression::Ptr	typeCheck (const StaticContext::Ptr &context, const SequenceType::Ptr &reqType)

virtual	~Expression ()

Public Functions inherited from QSharedData
	QSharedData ()
	Constructs a QSharedData object with a reference count of 0. More...

	QSharedData (const QSharedData &)
	Constructs a QSharedData object with reference count 0. More...

Public Functions inherited from QPatternist::CppCastingHelper< Expression >
const TCastTarget *	as () const

TCastTarget *	as ()

Public Functions inherited from QPatternist::SourceLocationReflection
virtual QSourceLocation	sourceLocation () const

	SourceLocationReflection ()

virtual	~SourceLocationReflection ()

Static Public Functions
static Expression::Ptr	verifyCardinality (const Expression::Ptr &operand, const Cardinality &card, const StaticContext::Ptr &context, const ReportContext::ErrorCode code=ReportContext::XPTY0004)

Static Public Functions inherited from QPatternist::Expression
static void	rewrite (Expression::Ptr &old, const Expression::Ptr &New, const StaticContext::Ptr &context)

Static Private Functions
static QString	wrongCardinality (const Cardinality &req, const Cardinality &got=Cardinality::empty())

Properties
const bool	m_allowsMany

const ReportContext::ErrorCode	m_errorCode

const Cardinality	m_reqCard

Additional Inherited Members
Public Types inherited from QPatternist::Expression
typedef QExplicitlySharedDataPointer< const Expression >	ConstPtr
	A smart pointer wrapping `const` Expression instances. More...

enum	ID { IDBooleanValue = 1, IDCountFN, IDEmptyFN, IDExistsFN, IDExpressionSequence, IDGeneralComparison, IDIfThenClause, IDIgnorableExpression, IDIntegerValue, IDPositionFN, IDStringValue, IDValueComparison, IDRangeVariableReference, IDContextItem, IDUserFunctionCallsite, IDExpressionVariableReference, IDAttributeConstructor, IDUpperCaseFN, IDLowerCaseFN, IDFirstItemPredicate, IDEmptySequence, IDReturnOrderBy, IDLetClause, IDForClause, IDPath, IDNamespaceConstructor, IDArgumentReference, IDGenericPredicate, IDAxisStep, IDFloat, IDCombineNodes, IDUnresolvedVariableReference, IDCardinalityVerifier }

typedef QList< Expression::Ptr >	List

typedef QFlags< Property >	Properties

enum	Property { UseContextItem = 1, DisableElimination = 1 << 1, IsEvaluated = 1 << 2, DisableTypingDeduction = 1 << 3, EmptynessFollowsChild = 1 << 4, RewriteToEmptyOnEmpty = 1 << 5, RequiresFocus = 1 << 6, AffectsOrderOnly = 1 << 7, RequiresContextItem = (1 << 8) \| RequiresFocus, CreatesFocusForLast = 1 << 9, LastOperandIsCollation = 1 << 10, DependsOnLocalVariable = (1 << 11) \| DisableElimination, EvaluationCacheRedundant = (1 << 12), IsNodeConstructor = 1 << 13, RequiresCurrentItem = 1 << 14 }

typedef QExplicitlySharedDataPointer< Expression >	Ptr
	A smart pointer wrapping mutable Expression instances. More...

typedef ::QAbstractXmlForwardIterator< Expression::Ptr >	QAbstractXmlForwardIterator

typedef QVector< Expression::Ptr >	Vector

Public Variables inherited from QSharedData
QAtomicInt	ref

Protected Functions inherited from QPatternist::SingleContainer
	SingleContainer (const Expression::Ptr &operand)

Protected Functions inherited from QPatternist::Expression
void	typeCheckOperands (const StaticContext::Ptr &context)

Protected Functions inherited from QPatternist::CppCastingHelper< Expression >
	CppCastingHelper ()

Protected Variables inherited from QPatternist::SingleContainer
Expression::Ptr	m_operand

Detailed Description

Verifies that the sequence an Expression evaluates to conforms to a Cardinality.

See also: XQuery 1.0 and XPath 2.0 Functions and Operators, 15.2 Functions That Test the Cardinality of Sequences

Author: Frans Englich frans.nosp@m..eng.nosp@m.lich@.nosp@m.noki.nosp@m.a.com

Definition at line 72 of file qcardinalityverifier_p.h.

Constructors and Destructors

◆ CardinalityVerifier()

CardinalityVerifier::CardinalityVerifier	(	const Expression::Ptr &	operand,
		const Cardinality &	card,
		const ReportContext::ErrorCode	code
	)

Definition at line 86 of file qcardinalityverifier.cpp.

Referenced by verifyCardinality().

                                          : SingleContainer(operand),
                                            m_reqCard(card),
                                            m_allowsMany(operand->staticType()->cardinality().allowsMany()),
                                            m_errorCode(code)
 {
     Q_ASSERT_X(m_reqCard != Cardinality::zeroOrMore(), Q_FUNC_INFO,
                "It makes no sense to use CardinalityVerifier for cardinality zero-or-more.");
 }

Functions

◆ accept()

ExpressionVisitorResult::Ptr CardinalityVerifier::accept ( const ExpressionVisitor::Ptr & visitor ) const

virtual

Implements QPatternist::Expression.

Definition at line 214 of file qcardinalityverifier.cpp.

 {
     return visitor->visit(this);
 }

◆ actualReflection()

const SourceLocationReflection * CardinalityVerifier::actualReflection ( ) const

virtual

Returns this.

Reimplemented from QPatternist::Expression.

Definition at line 189 of file qcardinalityverifier.cpp.

 {
     return m_operand->actualReflection();
 }

◆ compress()

Expression::Ptr CardinalityVerifier::compress ( const StaticContext::Ptr & context )

virtual

If the static cardinality of the operand is within the required cardinality, the operand is returned as is, since results will always be valid and hence is not a CardinalityVerifier necessary.

Reimplemented from QPatternist::Expression.

Definition at line 194 of file qcardinalityverifier.cpp.

 {
     if(m_reqCard.isMatch(m_operand->staticType()->cardinality()))
         return m_operand->compress(context);
     else
         return SingleContainer::compress(context);
 }

◆ evaluateSequence()

Item::Iterator::Ptr CardinalityVerifier::evaluateSequence ( const DynamicContext::Ptr & context ) const

virtual

Evaluate this Expression by iterating over it. This is a central function for evaluating expressions.

Expressions must always always return a valid QAbstractXmlForwardIterator and may never return 0. If an empty result is of interest to be returned, the EmptyIterator should be returned.

The default implementation returns a SingletonIterator over the item returned from evaluateSingleton().

Note: This function may raise an exception when calling, not only when QAbstractXmlForwardIterator::next() is called on the return value. This is because in some cases evaluateSingleton() is called directly.

Reimplemented from QPatternist::Expression.

Definition at line 98 of file qcardinalityverifier.cpp.

 {
     const Item::Iterator::Ptr it(m_operand->evaluateSequence(context));
     const Item next(it->next());
 
     if(next)
     {
         const Item next2(it->next());
 
         if(next2)
         {
             if(m_reqCard.allowsMany())
             {
                 Item::List start;
                 start.append(next);
                 start.append(next2);
 
                 return Item::Iterator::Ptr(new InsertionIterator(it, 1, makeListIterator(start)));
             }
             else
             {
                 context->error(wrongCardinality(m_reqCard, Cardinality::twoOrMore()), m_errorCode, this);
                 return CommonValues::emptyIterator;
             }
         }
         else
         {
             /* We might be instantiated for the empty sequence. */
             if(m_reqCard.isEmpty())
             {
                 context->error(wrongCardinality(m_reqCard, Cardinality::twoOrMore()), m_errorCode, this);
                 return CommonValues::emptyIterator;
             }
             else
                 return makeSingletonIterator(next);
         }
     }
     else
     {
         if(m_reqCard.allowsEmpty())
             return CommonValues::emptyIterator;
         else
         {
             context->error(wrongCardinality(m_reqCard, Cardinality::twoOrMore()), m_errorCode, this);
             return CommonValues::emptyIterator;
         }
     }
 }

◆ evaluateSingleton()

Item CardinalityVerifier::evaluateSingleton ( const DynamicContext::Ptr & context ) const

virtual

Reimplemented from QPatternist::Expression.

Definition at line 147 of file qcardinalityverifier.cpp.

 {
     if(m_allowsMany)
     {
         const Item::Iterator::Ptr it(m_operand->evaluateSequence(context));
         const Item item(it->next());
 
         if(item)
         {
             if(it->next())
             {
                 context->error(wrongCardinality(m_reqCard, Cardinality::twoOrMore()),
                                m_errorCode, this);
                 return Item();
             }
             else
                 return item;
         }
         else if(m_reqCard.allowsEmpty())
             return Item();
         else
         {
             context->error(wrongCardinality(m_reqCard), m_errorCode, this);
             return Item();
         }
     }
     else
     {
         const Item item(m_operand->evaluateSingleton(context));
 
         if(item)
             return item;
         else if(m_reqCard.allowsEmpty())
             return Item();
         else
         {
             context->error(wrongCardinality(m_reqCard), m_errorCode, this);
             return Item();
         }
     }
 }

◆ expectedOperandTypes()

SequenceType::List CardinalityVerifier::expectedOperandTypes ( ) const

virtual

Returns a list of Sequence Types, describing the type of each of the expression's operands. Hence, this function has a relationship to the operands() function:

- The lengths of the lists returned by expectedOperandTypes()
and operands() should always be equal in length, since one
cannot describe the type of a non-existent operand(and all
operands must have type information).
- A significant difference between the two functions is that while
the type of objects in the list returned by operands() may vary
between compilations/static context, simply because the particular
Expression is part of different XPath expressions, the
types in the list returned by expectedOperandTypes is always the same
since the function/operator signature never changes.

This function should not be confused with staticType(), which returns the static type of the expression itself, not its operands. The function call is an expression where this is clear: the type of the return value is not the same as the arguments' types. The static type of the operands supplied to the expression can be determined via the staticType() function of the instances returned by operands().

If the expression has no operands, an empty list should be returned.

Implements QPatternist::Expression.

Definition at line 202 of file qcardinalityverifier.cpp.

 {
     SequenceType::List result;
     result.append(CommonSequenceTypes::ZeroOrMoreItems);
     return result;
 }

◆ id()

Expression::ID CardinalityVerifier::id ( ) const

virtual

This property, which has no setter, returns an enum value that uniquely identifies this Expression. Patternist makes no use of C++'s dynamic_cast feature, but uses this polymorphic function instead.

Returns: always IgnorableExpression.

Reimplemented from QPatternist::Expression.

Definition at line 219 of file qcardinalityverifier.cpp.

 {
     return IDCardinalityVerifier;
 }

◆ staticType()

SequenceType::Ptr CardinalityVerifier::staticType ( ) const

virtual

Returns: the static type of this Expression. For example, an 'and' expression have as static type xs:boolean

Implements QPatternist::Expression.

Definition at line 209 of file qcardinalityverifier.cpp.

 {
     return makeGenericSequenceType(m_operand->staticType()->itemType(), m_reqCard);
 }

◆ verifyCardinality()

Expression::Ptr CardinalityVerifier::verifyCardinality	(	const Expression::Ptr &	operand,
		const Cardinality &	card,
		const StaticContext::Ptr &	context,
		const ReportContext::ErrorCode	code = `ReportContext::XPTY0004`
	)

static

A utility function for determining whether the static type of an Expression matches a cardinality. More specifically, this function performs the cardinality verification part of the Function Conversion Rules.

Definition at line 62 of file qcardinalityverifier.cpp.

Referenced by QPatternist::TypeChecker::applyFunctionConversion(), and QPatternist::ExpressionSequence::typeCheck().

 {
     const Cardinality opCard(operand->staticType()->cardinality());
 
     if(requiredCard.isMatch(opCard))
         return operand;
     else if(requiredCard.canMatch(opCard))
         return Expression::Ptr(new CardinalityVerifier(operand, requiredCard, code));
     else if(context->compatModeEnabled() &&
             !opCard.isEmpty())
     {
         return GenericPredicate::createFirstItem(operand);
     }
     else
     {
         /* Sequences within this cardinality can never match. */
         context->error(wrongCardinality(requiredCard, opCard), code, operand.data());
         return operand;
     }
 }

◆ wrongCardinality()

QString CardinalityVerifier::wrongCardinality	(	const Cardinality &	req,
		const Cardinality &	got = `Cardinality::empty()`
	)

inlinestaticprivate

Centralizes a message string in order to increase consistency and reduce work for translators.

Definition at line 55 of file qcardinalityverifier.cpp.

Referenced by evaluateSequence(), evaluateSingleton(), and verifyCardinality().

 {
     return QtXmlPatterns::tr("Required cardinality is %1; got cardinality %2.")
                 .arg(formatType(req), formatType(got));
 }

Properties

◆ m_allowsMany

const bool QPatternist::CardinalityVerifier::m_allowsMany

private

Definition at line 119 of file qcardinalityverifier_p.h.

Referenced by evaluateSingleton().

◆ m_errorCode

const ReportContext::ErrorCode QPatternist::CardinalityVerifier::m_errorCode

private

Definition at line 120 of file qcardinalityverifier_p.h.

Referenced by evaluateSequence(), and evaluateSingleton().

◆ m_reqCard

const Cardinality QPatternist::CardinalityVerifier::m_reqCard

private

Definition at line 118 of file qcardinalityverifier_p.h.

Referenced by CardinalityVerifier(), compress(), evaluateSequence(), evaluateSingleton(), and staticType().

The documentation for this class was generated from the following files:

/src/xmlpatterns/janitors/qcardinalityverifier_p.h
/src/xmlpatterns/janitors/qcardinalityverifier.cpp

Public Functions

Static Public Functions

Static Private Functions

Properties

Additional Inherited Members

Detailed Description

Constructors and Destructors

◆ CardinalityVerifier()

Functions

◆ accept()

◆ actualReflection()

◆ compress()

◆ evaluateSequence()

◆ evaluateSingleton()

◆ expectedOperandTypes()

◆ id()

◆ staticType()

◆ verifyCardinality()

◆ wrongCardinality()

Properties

◆ m_allowsMany

◆ m_errorCode

◆ m_reqCard