When combined with other components, implements xsl:apply-templates. More...

#include <qapplytemplate_p.h>

Inheritance diagram for QPatternist::ApplyTemplate:

Public Types
typedef QExplicitlySharedDataPointer< ApplyTemplate >	Ptr

Public Types inherited from QPatternist::UnlimitedContainer
enum	CardinalityComputation { ProductOfCardinality, UnionOfCardinality }

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

	ApplyTemplate (const TemplateMode::Ptr &mode, const WithParam::Hash &withParams, const TemplateMode::Ptr &defaultMode)
	`mode` may be `null`. If it is, ApplyTemplate interprets that as that it should use the #current mode. More...

virtual Expression::Ptr	body () const
	Returns the body of the function/template/component that is being called. More...

virtual CallTargetDescription::Ptr	callTargetDescription () const

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

virtual bool	configureRecursion (const CallTargetDescription::Ptr &sign)

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

Item	mapToItem (const QXmlNodeModelIndex &node, const DynamicContext::Ptr &context) const

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

TemplateMode::Ptr	mode () const

virtual Properties	properties () const

virtual SequenceType::Ptr	staticType () const

Public Functions inherited from QPatternist::TemplateInvoker
virtual SequenceType::List	expectedOperandTypes () const

const WithParam::Hash &	withParams () const

Public Functions inherited from QPatternist::CallSite
bool	isRecursive () const

QXmlName	name () const

void	setIsRecursive (const bool value)

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

virtual Expression::List	operands () const

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

	UnlimitedContainer (const Expression::List &operands=Expression::List())

Public Functions inherited from QPatternist::Expression
virtual const SourceLocationReflection *	actualReflection () const
	Returns `this`. More...

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 Item	evaluateSingleton (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

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 ()

Private Types
typedef QExplicitlySharedDataPointer< const ApplyTemplate >	ConstPtr

Private Functions
TemplateMode::Ptr	effectiveMode (const DynamicContext::Ptr &context) const

Template::Ptr	findTemplate (const DynamicContext::Ptr &context, const TemplateMode::Ptr &templateMode) const

Properties
TemplateMode::Ptr	m_defaultMode

const TemplateMode::Ptr	m_mode

Additional Inherited Members
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 QPatternist::TemplateInvoker
WithParam::Hash	m_withParams

Public Variables inherited from QSharedData
QAtomicInt	ref

Protected Functions inherited from QPatternist::TemplateInvoker
	TemplateInvoker (const WithParam::Hash &withParams, const QXmlName &name=QXmlName())

Protected Functions inherited from QPatternist::CallSite
	CallSite (const QXmlName &name=QXmlName())

Protected Functions inherited from QPatternist::UnlimitedContainer
template<CardinalityComputation suppliedCard>
SequenceType::Ptr	operandsUnionType () const

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::UnlimitedContainer
Expression::List	m_operands

Detailed Description

When combined with other components, implements xsl:apply-templates.

Note that ApplyTemplate isn't named ApplyTemplates. The reason for this is that ApplyTemplate doesn't do the iteration part. An <xsl:apply-templates/> instruction is rewritten into:

child::node/() map apply-template()

Hence, this expression requires a focus, although it can consist of atomic values.

Since: 4.5

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

Definition at line 81 of file qapplytemplate_p.h.

Typedefs

◆ ConstPtr

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

private

Definition at line 121 of file qapplytemplate_p.h.

◆ Ptr

typedef QExplicitlySharedDataPointer<ApplyTemplate> QPatternist::ApplyTemplate::Ptr

Definition at line 84 of file qapplytemplate_p.h.

Constructors and Destructors

◆ ApplyTemplate()

ApplyTemplate::ApplyTemplate	(	const TemplateMode::Ptr &	mode,
		const WithParam::Hash &	withParams,
		const TemplateMode::Ptr &	defaultMode
	)

mode may be null. If it is, ApplyTemplate interprets that as that it should use the #current mode.

See also: StaticContext::currentTemplateMode()

Definition at line 57 of file qapplytemplate.cpp.

                                                                  : TemplateInvoker(withParams)
                                                                    , m_mode(mode)
                                                                    , m_defaultMode(defaultMode)
 {
     Q_ASSERT_X(m_mode || m_defaultMode, Q_FUNC_INFO,
                "Either a mode, or the default mode must be supplied.");
 }

Functions

◆ accept()

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

virtual

Implements QPatternist::Expression.

Definition at line 181 of file qapplytemplate.cpp.

 {
     return visitor->visit(this);
 }

◆ body()

Expression::Ptr ApplyTemplate::body ( ) const

virtual

Returns the body of the function/template/component that is being called.

Implements QPatternist::CallSite.

Definition at line 198 of file qapplytemplate.cpp.

 {
     Q_ASSERT_X(false, Q_FUNC_INFO, "We're not expected to be called.");
     return Expression::Ptr();
 }

◆ callTargetDescription()

CallTargetDescription::Ptr ApplyTemplate::callTargetDescription ( ) const

virtual

Implements QPatternist::CallSite.

Definition at line 204 of file qapplytemplate.cpp.

 {
     Q_ASSERT_X(false, Q_FUNC_INFO, "We're not expected to be called.");
     return CallTargetDescription::Ptr();
 }

◆ compress()

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

virtual

compress() is the last stage performs in compiling an expression, done after the initial AST build and calling typeCheck(). compress() performs crucial simplifications, either by having drastic performance implications or that some expressions depend on it for proper behavior.

The default implementation performs a sparse conditional constant propagation. In short, a recursive process is performed in the AST which examines if the Expression's operands are constant values, and if so, performs a const fold(AST rewrite) into the result of evaluating the expression in question. This default behavior can be disabled by letting properties() return DisableElimination.

This compress() stage can be relative effective due to the design of XPath, in part because intrinsic functions are heavily used. Many Expressions override compress() and do optimizations specific to what they do. Also, many Expressions performs optimizations in their typeCheck().

Parameters

context the static context. Supplies compile time information, and is the channel for communicating error messages.

See also: Wikipedia, the free encyclopedia, Sparse conditional constant propagation; Wikipedia, the free encyclopedia, Intrinsic function; Wikipedia, the free encyclopedia, Compiler optimization

Reimplemented from QPatternist::TemplateInvoker.

Definition at line 167 of file qapplytemplate.cpp.

 {
     /* If we have a mode, we will never need the default mode. */
     if(m_mode)
         m_defaultMode.reset();
 
     return TemplateInvoker::compress(context);
 }

◆ configureRecursion()

bool ApplyTemplate::configureRecursion ( const CallTargetDescription::Ptr & sign )

virtual

Called in the earliest stages of the compilation process. sign can be any function signature for a user declared function. If sign matches this UserFunctionCallsite, it means the UserFunction represented by sign is recursive and that this UserFunctionCallsite should take appropriate measures.

Returns: true if is recursive, otherwise false

Implements QPatternist::CallSite.

Definition at line 191 of file qapplytemplate.cpp.

 {
     Q_ASSERT_X(false, Q_FUNC_INFO, "We're not expected to be called.");
     Q_UNUSED(sign);
     return false;
 }

◆ effectiveMode()

TemplateMode::Ptr ApplyTemplate::effectiveMode ( const DynamicContext::Ptr & context ) const

inlineprivate

Definition at line 80 of file qapplytemplate.cpp.

Referenced by evaluateSequence().

 {
     if(m_mode)
         return m_mode;
     else
     {
         const TemplateMode::Ptr currentMode(context->currentTemplateMode());
 
         if(currentMode)
             return currentMode;
         else
             return m_defaultMode;
     }
 }

◆ evaluateSequence()

Item::Iterator::Ptr ApplyTemplate::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 137 of file qapplytemplate.cpp.

Referenced by mapToSequence().

 {
     const TemplateMode::Ptr templateMode(effectiveMode(context));
     const Template::Ptr &templateMatch = findTemplate(context, templateMode);
 
     if(templateMatch)
         return templateMatch->body->evaluateSequence(templateMatch->createContext(this, context, false));
     else
     {
         /* None of our templates matched. Proceed with a built-in. */
         const Item current(context->contextItem());
         // TODO it can be an atomic value?
         const QXmlNodeModelIndex::NodeKind kind(current.asNode().kind());
 
         if(kind == QXmlNodeModelIndex::Element || kind == QXmlNodeModelIndex::Document)
         {
             pDebug() << "No template match, using builtin template for element() | document-node()";
 
             const Item::Iterator::Ptr focusIterator(makeItemMappingIterator<Item>(ConstPtr(this),
                                                                                   current.asNode().iterate(QXmlNodeModelIndex::AxisChild),
                                                                                   context));
 
             const DynamicContext::Ptr focus(context->createFocus());
             focus->setFocusIterator(focusIterator);
             return makeSequenceMappingIterator<Item>(ConstPtr(this), focusIterator, focus);
         }
         return CommonValues::emptyIterator;
     }
 }

◆ findTemplate()

Template::Ptr ApplyTemplate::findTemplate	(	const DynamicContext::Ptr &	context,
		const TemplateMode::Ptr &	templateMode
	)		const

private

Definition at line 95 of file qapplytemplate.cpp.

Referenced by evaluateSequence().

 {
     const int count = templateMode->templatePatterns.count();
     Template::Ptr result;
     /* It's redundant to initialize these values, but it suppresses false
      * positives with GCC. */
     PatternPriority priority = 0;
     TemplatePattern::ID id = -1;
 
     /* Possible optimization: detecting ambiguous rule matches could be forked off to a
      * low prioirity thread. */
     for(int i = 0; i < count; ++i)
     {
         const TemplatePattern::Ptr &candidate = templateMode->templatePatterns.at(i);
         if(candidate->matchPattern()->evaluateEBV(context))
         {
             if(result)
             {
                 if(   candidate->id() != id
                    && candidate->priority() == priority
                    && candidate->templateTarget()->importPrecedence ==
                                                         result->importPrecedence)
                 {
                     context->error(QtXmlPatterns::tr("Ambiguous rule match."),
                                    ReportContext::XTRE0540, this);
                 }
                 else
                     break;
             }
             else
             {
                 result = candidate->templateTarget();
                 priority = candidate->priority();
                 id = candidate->id();
             }
         }
     }
 
     return result;
 }

◆ mapToItem()

Item ApplyTemplate::mapToItem	(	const QXmlNodeModelIndex &	node,
		const DynamicContext::Ptr &	context
	)		const

inline

The only reason this function exists, is in order to convert QXmlNodeModelIndex to QPatternist::Item. So, this is a huge performance setback. It applies for one of the builtin templates.

Definition at line 67 of file qapplytemplate.cpp.

 {
     return Item(node);
 }

◆ mapToSequence()

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

inline

Definition at line 73 of file qapplytemplate.cpp.

 {
     Q_UNUSED(item);
     return evaluateSequence(context);
 }

◆ mode()

TemplateMode::Ptr QPatternist::ApplyTemplate::mode ( ) const

inline

Definition at line 135 of file qapplytemplate_p.h.

     {
         return m_mode;
     }

◆ properties()

Expression::Properties ApplyTemplate::properties ( ) const

virtual

Returns: a bitwise OR'd value of properties, describing the characteristics of the expression. These properties affects how this Expression is treated in for example type checking stages.

The default implementation returns 0. Override and let the function return a different value, if that's of interest.

An important decision when re-implementing properties() is whether to OR in the properties() of ones operands. For instance, if an operand has RequiresFocus set, that flag nost likely applies to the apparent as well, since it depends on its operand.

See also: deepProperties()

Returns: Expression::None, meaning no special properties

Reimplemented from QPatternist::Expression.

Definition at line 186 of file qapplytemplate.cpp.

 {
     return RequiresFocus | DisableElimination;
 }

◆ staticType()

SequenceType::Ptr ApplyTemplate::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 176 of file qapplytemplate.cpp.

 {
     return CommonSequenceTypes::ZeroOrMoreItems;
 }

Properties

◆ m_defaultMode

TemplateMode::Ptr QPatternist::ApplyTemplate::m_defaultMode

private

Definition at line 130 of file qapplytemplate_p.h.

Referenced by ApplyTemplate(), compress(), and effectiveMode().

◆ m_mode

const TemplateMode::Ptr QPatternist::ApplyTemplate::m_mode

private

Note: You typically want to use effectiveMode().

Definition at line 128 of file qapplytemplate_p.h.

Referenced by ApplyTemplate(), compress(), effectiveMode(), and mode().

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

/src/xmlpatterns/expr/qapplytemplate_p.h
/src/xmlpatterns/expr/qapplytemplate.cpp

Public Types

Public Functions

Private Types

Private Functions

Properties

Additional Inherited Members

Detailed Description

Typedefs

◆ ConstPtr

◆ Ptr

Constructors and Destructors

◆ ApplyTemplate()

Functions

◆ accept()

◆ body()

◆ callTargetDescription()

◆ compress()

◆ configureRecursion()

◆ effectiveMode()

◆ evaluateSequence()

◆ findTemplate()

◆ mapToItem()

◆ mapToSequence()

◆ mode()

◆ properties()

◆ staticType()

Properties

◆ m_defaultMode

◆ m_mode