Performs atomization. Effectively, it is an implementation of the fn:data() function. More...

#include <qatomizer_p.h>

Inheritance diagram for QPatternist::Atomizer:

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

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

	Atomizer (const Expression::Ptr &operand)

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

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

virtual SequenceType::List	expectedOperandTypes () const

Item::Iterator::Ptr	mapToSequence (const Item &item, const DynamicContext::Ptr &context) const

virtual SequenceType::Ptr	staticType () const

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

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)

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

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

virtual ID	id () 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 ()

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 ()

Private Types
typedef QExplicitlySharedDataPointer< const Atomizer >	ConstPtr

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

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

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

Performs atomization. Effectively, it is an implementation of the fn:data() function.

See also: XQuery 1.0 and XPath 2.0 Functions and Operators, 2.4 fn:data; XML Path Language (XPath) 2.0, 2.4.2 Atomization

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

Definition at line 76 of file qatomizer_p.h.

Typedefs

◆ ConstPtr

typedef QExplicitlySharedDataPointer<const Atomizer> QPatternist::Atomizer::ConstPtr

private

Definition at line 102 of file qatomizer_p.h.

Constructors and Destructors

◆ Atomizer()

Atomizer::Atomizer ( const Expression::Ptr & operand )

Definition at line 54 of file qatomizer.cpp.

                                                : SingleContainer(operand)
 {
 }

Functions

◆ accept()

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

virtual

Implements QPatternist::Expression.

Definition at line 115 of file qatomizer.cpp.

 {
     return visitor->visit(this);
 }

◆ actualReflection()

const SourceLocationReflection * Atomizer::actualReflection ( ) const

virtual

Returns this.

Reimplemented from QPatternist::Expression.

Definition at line 120 of file qatomizer.cpp.

 {
     return m_operand->actualReflection();
 }

◆ evaluateSequence()

Item::Iterator::Ptr Atomizer::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 67 of file qatomizer.cpp.

 {
     return makeSequenceMappingIterator<Item>(ConstPtr(this),
                                              m_operand->evaluateSequence(context),
                                              context);
 }

◆ evaluateSingleton()

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

virtual

Reimplemented from QPatternist::Expression.

Definition at line 74 of file qatomizer.cpp.

 {
     const Item item(m_operand->evaluateSingleton(context));
 
     if(!item) /* Empty is allowed, cardinality is considered '?' */
         return Item();
 
     const Item::Iterator::Ptr it(mapToSequence(item, context));
     Q_ASSERT_X(it, Q_FUNC_INFO, "A valid QAbstractXmlForwardIterator must always be returned.");
 
     Item result(it->next());
     Q_ASSERT_X(!it->next(), Q_FUNC_INFO,
                "evaluateSingleton should never be used if the cardinality is two or more");
 
     return result;
 }

◆ expectedOperandTypes()

SequenceType::List Atomizer::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 108 of file qatomizer.cpp.

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

◆ mapToSequence()

Item::Iterator::Ptr Atomizer::mapToSequence	(	const Item &	item,
		const DynamicContext::Ptr &	context
	)		const

inline

Definition at line 58 of file qatomizer.cpp.

Referenced by evaluateSingleton().

 {
     /* Function & Operators, 2.4.2 fn:data, says "If the node does not have a
      * typed value an error is raised [err:FOTY0012]."
      * When does a node not have a typed value? */
     Q_ASSERT(item);
     return item.sequencedTypedValue();
 }

◆ staticType()

SequenceType::Ptr Atomizer::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 101 of file qatomizer.cpp.

 {
     const SequenceType::Ptr opt(m_operand->staticType());
     return makeGenericSequenceType(opt->itemType()->atomizedType(),
                                    opt->cardinality());
 }

◆ typeCheck()

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

virtual

Makes an early compression, by returning the result of the type checked operand, if the operand has the static type xs:anyAtomicType(no atomization needed).

Reimplemented from QPatternist::Expression.

Definition at line 91 of file qatomizer.cpp.

 {
     /* Compress -- the earlier the better. */
     if(BuiltinTypes::xsAnyAtomicType->xdtTypeMatches(m_operand->staticType()->itemType()))
         return m_operand->typeCheck(context, reqType);
 
     return SingleContainer::typeCheck(context, reqType);
 }

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

/src/xmlpatterns/janitors/qatomizer_p.h
/src/xmlpatterns/janitors/qatomizer.cpp

Public Functions

Private Types

Additional Inherited Members

Detailed Description

Typedefs

◆ ConstPtr

Constructors and Destructors

◆ Atomizer()

Functions

◆ accept()

◆ actualReflection()

◆ evaluateSequence()

◆ evaluateSingleton()

◆ expectedOperandTypes()

◆ mapToSequence()

◆ staticType()

◆ typeCheck()