Performs a call to a UserFunction. More...

#include <quserfunctioncallsite_p.h>

Inheritance diagram for QPatternist::UserFunctionCallsite:

Public Types
typedef QList< UserFunctionCallsite::Ptr >	List

typedef QExplicitlySharedDataPointer< UserFunctionCallsite >	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

FunctionSignature::Arity	arity () const

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

virtual CallTargetDescription::Ptr	callTargetDescription () const

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

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

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

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

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

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

virtual SequenceType::List	expectedOperandTypes () const
	Returns the types declared in the function declaration. More...

virtual ID	id () const

bool	isSignatureValid (const FunctionSignature::Ptr &sign) const

virtual Expression::Properties	properties () const

void	setSource (const UserFunction::Ptr &userFunction, const VariableSlotID cacheSlotOffset)

virtual SequenceType::Ptr	staticType () const

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

	UserFunctionCallsite (const QXmlName name, const FunctionSignature::Arity arity)

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 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

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 Functions
DynamicContext::Ptr	bindVariables (const DynamicContext::Ptr &context) const

Properties
const FunctionSignature::Arity	m_arity

Expression::Ptr	m_body

VariableSlotID	m_expressionSlotOffset

UserFunction::Ptr	m_functionDeclaration

Related Functions
(Note that these are not member functions.)
static QString	formatFunction (const UserFunctionCallsite::Ptr &func)
	Formats UserFunctionCallsite. More...

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 QSharedData
QAtomicInt	ref

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

Performs a call to a UserFunction.

UserFunctionCallsite is the call site to a function that has been declared in the query using declare function. That is, it is never used for builtin functions such as fn:count().

See also: UserFunction; ArgumentReference

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

Definition at line 78 of file quserfunctioncallsite_p.h.

Typedefs

◆ List

typedef QList<UserFunctionCallsite::Ptr> QPatternist::UserFunctionCallsite::List

Definition at line 82 of file quserfunctioncallsite_p.h.

◆ Ptr

typedef QExplicitlySharedDataPointer<UserFunctionCallsite> QPatternist::UserFunctionCallsite::Ptr

Definition at line 81 of file quserfunctioncallsite_p.h.

Constructors and Destructors

◆ UserFunctionCallsite()

UserFunctionCallsite::UserFunctionCallsite	(	const QXmlName	name,
		const FunctionSignature::Arity	arity
	)

Definition at line 52 of file quserfunctioncallsite.cpp.

                                                                             : CallSite(nameP)
                                                                               , m_arity(ar)
                                                                               , m_expressionSlotOffset(-2)
 
 {
 }

Functions

◆ accept()

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

virtual

Implements QPatternist::Expression.

Definition at line 182 of file quserfunctioncallsite.cpp.

 {
     return visitor->visit(this);
 }

◆ arity()

FunctionSignature::Arity UserFunctionCallsite::arity ( ) const

Definition at line 235 of file quserfunctioncallsite.cpp.

 {
     return m_arity;
 }

◆ bindVariables()

DynamicContext::Ptr UserFunctionCallsite::bindVariables ( const DynamicContext::Ptr & context ) const

private

Creates a new context sets the arguments, and returns it.

Definition at line 80 of file quserfunctioncallsite.cpp.

Referenced by body(), evaluateEBV(), evaluateSequence(), evaluateSingleton(), and evaluateToSequenceReceiver().

 {
     const DynamicContext::Ptr stackContext(context->createStack());
     Q_ASSERT(stackContext);
 
     const Expression::List::const_iterator end(m_operands.constEnd());
     Expression::List::const_iterator it(m_operands.constBegin());
 
     VariableSlotID slot = m_expressionSlotOffset;
 
     for(; it != end; ++it)
     {
         stackContext->setExpressionVariable(slot,
                                             Expression::Ptr(new DynamicContextStore(*it, context)));
         ++slot;
     }
 
     return stackContext;
 }

◆ body()

Expression::Ptr QPatternist::UserFunctionCallsite::body ( ) const

inlinevirtual

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

Implements QPatternist::CallSite.

Definition at line 131 of file quserfunctioncallsite_p.h.

         {
             return m_body;
         }

◆ callTargetDescription()

CallTargetDescription::Ptr UserFunctionCallsite::callTargetDescription ( ) const

virtual

Implements QPatternist::CallSite.

Definition at line 240 of file quserfunctioncallsite.cpp.

Referenced by body().

 {
     return m_functionDeclaration->signature();
 }

◆ compress()

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

virtual

We call compress on our body.

Reimplemented from QPatternist::Expression.

Definition at line 152 of file quserfunctioncallsite.cpp.

 {
     if(!isRecursive())
         rewrite(m_body, m_body->compress(context), context);
 
     return CallSite::compress(context);
 }

◆ configureRecursion()

bool UserFunctionCallsite::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 201 of file quserfunctioncallsite.cpp.

Referenced by body().

 {
     Q_ASSERT(sign);
 
     setIsRecursive(isSignatureValid(sign));
     return isRecursive();
 }

◆ evaluateEBV()

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

virtual

Determines the Effective Boolean Value of the expression.

The Effective Boolean Value of a value is not necessarily the same as converting the value to a new value of type xs:boolean.

Note that this function cannot return the empty sequence, evaluateSingleton() must be overridden in order to be able to do that.

The default implementation results in a type error. Hence, this function must be overridden if such behavior is not of interest.

See also: XML Path Language (XPath) 2.0, 2.4.3 Effective Boolean Value

Reimplemented from QPatternist::Expression.

Definition at line 70 of file quserfunctioncallsite.cpp.

 {
     return m_body->evaluateEBV(bindVariables(context));
 }

◆ evaluateSequence()

Item::Iterator::Ptr UserFunctionCallsite::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 60 of file quserfunctioncallsite.cpp.

 {
     return m_body->evaluateSequence(bindVariables(context));
 }

◆ evaluateSingleton()

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

virtual

Reimplemented from QPatternist::Expression.

Definition at line 65 of file quserfunctioncallsite.cpp.

 {
     return m_body->evaluateSingleton(bindVariables(context));
 }

◆ evaluateToSequenceReceiver()

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

virtual

Evaluates this Expression by sending its output to DynamicContext::outputReceiver().

Reimplemented from QPatternist::Expression.

Definition at line 75 of file quserfunctioncallsite.cpp.

 {
     m_body->evaluateToSequenceReceiver(bindVariables(context));
 }

◆ expectedOperandTypes()

SequenceType::List UserFunctionCallsite::expectedOperandTypes ( ) const

virtual

Returns the types declared in the function declaration.

See also: CallTemplate::expectedOperandTypes()

Implements QPatternist::Expression.

Definition at line 100 of file quserfunctioncallsite.cpp.

 {
     SequenceType::List result;
 
     if(m_functionDeclaration)
     {
         const FunctionArgument::List args(m_functionDeclaration->signature()->arguments());
         const FunctionArgument::List::const_iterator end(args.constEnd());
         FunctionArgument::List::const_iterator it(args.constBegin());
 
         for(; it != end; ++it)
             result.append((*it)->type());
     }
     else
         result.append(CommonSequenceTypes::ZeroOrMoreItems);
 
     return result;
 }

◆ id()

Expression::ID UserFunctionCallsite::id ( ) const

virtual

Returns: always IDUserFunctionCallsite.

Reimplemented from QPatternist::Expression.

Definition at line 187 of file quserfunctioncallsite.cpp.

 {
     return IDUserFunctionCallsite;
 }

◆ isSignatureValid()

bool UserFunctionCallsite::isSignatureValid ( const FunctionSignature::Ptr & sign ) const

Returns: true, if a function definition with signature sign would be valid to call from this callsite, otherwise false.

Definition at line 192 of file quserfunctioncallsite.cpp.

Referenced by configureRecursion().

 {
     Q_ASSERT(sign);
 
     return sign->name() == name()
            &&
            sign->isArityValid(m_arity);
 }

◆ properties()

Expression::Properties UserFunctionCallsite::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 160 of file quserfunctioncallsite.cpp.

 {
     return DisableElimination;
 }

◆ setSource()

void UserFunctionCallsite::setSource	(	const UserFunction::Ptr &	userFunction,
		const VariableSlotID	cacheSlotOffset
	)

If slotOffset is -1, it means this function has no arguments.

Definition at line 209 of file quserfunctioncallsite.cpp.

 {
     m_functionDeclaration = userFunction;
     m_body = userFunction->body();
     m_expressionSlotOffset = userFunction->expressionSlotOffset();
 
     const int len = m_operands.size();
 
     const VariableDeclaration::List varDecls(userFunction->argumentDeclarations());
 
     for(int i = 0; i < len; ++i)
     {
         /* We don't want evaluation caches for range variables, it's not necessary since
          * the item is already cached in DynamicContext::rangeVariable(). */
         if(m_operands.at(i)->is(IDRangeVariableReference))
             continue;
 
         /* Note that we pass in cacheSlotOffset + i here instead of varDecls.at(i)->slot since
          * we want independent caches for each callsite. */
         m_operands[i] = Expression::Ptr(new EvaluationCache<false>(m_operands.at(i),
                                                                    varDecls.at(i).data(),
                                                                    cacheSlotOffset + i));
     }
 }

◆ staticType()

SequenceType::Ptr UserFunctionCallsite::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 165 of file quserfunctioncallsite.cpp.

 {
     /* Our return type, is the static type of the function body. We could have also used
      * m_functionDeclaration->signature()->returnType(), but it doesn't get updated
      * when function conversion is applied.
      * We can't use m_body's type if we're recursive, because m_body computes its type
      * from its children, and we're at least one of the children. Hence, we would
      * recurse infinitely if we did.
      *
      * m_body can be null here if we're called before setSource().
      */
     if(isRecursive() || !m_body)
         return CommonSequenceTypes::ZeroOrMoreItems; // TODO use the declaration, it can have a type explicitly.
     else
         return m_body->staticType();
 }

◆ typeCheck()

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

virtual

This implementation guarantees to never rewrite away this Expression, but at most rewrite it as a child of another expression(that presumably have a type checking role). It is therefore always safe to override this function and call this implementation and not worry about that this Expression becomes deleted.

Many Expressions override typeCheck() and performs optimizations, as opposed to doing it in the compress() stage. This is due to that the design of those Expressions often are tied to that certain simplifications are done at the typeCheck() stage of the compilation process or that it in some other way is related to what the typeCheck() do. Also, the earlier the AST can be simplified, the better the chances are for subsequent optimizations.

It is important that the super class's typeCheck() is called before doing any custom type checking, since the call can change the children(notably, the childrens' static types). For example, if the Expression, MyExpression in the example, does not match the required type, typeCheck returns the Expression wrapped in for example ItemVerifier, CardinalityVerifier, or both.

typeCheck() may be called many times. typeCheck() must either raise an error if this Expression is an invalid expression. Thus, it is guaranteed that an Expression is valid after typeCheck() is called.

Parameters

context	supplies information, such as namespace bindings and available function signatures, that can be needed at compilation time. `context` is guaranteed by the caller to never null.
reqType	the static type that this Expression must match when evaluated. `reqType` is guaranteed by the caller to never null.

Returns: an Expression that can be this Expression, or another expression, which somehow is necessary for making this Expression conforming to reqType

Reimplemented from QPatternist::Expression.

Definition at line 119 of file quserfunctioncallsite.cpp.

 {
     /* The parser calls TypeChecker::applyFunctionConversion() on user function
      * bodies, possibly indirectly, before all function call sites have been
      * resolved. Hence it's possible that we're called before before the usual
      * typeCheck() pass, and hence before we have been resolved/checked and
      * subsequently m_functionDeclaration set. Therefore, encounter for that below.
      *
      * UnresolvedVariableReference::typeCheck() has the same dilemma.
      */
 
     /* Ensure that the return value of the function is properly
      * converted/does match from where it is called(which is here). */
     if(isRecursive() || !m_functionDeclaration)
         return CallSite::typeCheck(context, reqType);
     else
     {
         /* Update, such that we use a recent version of the body that has typeCheck()
          * and compress() rewrites included. */
         m_body = m_functionDeclaration->body();
 
         /* Note, we can't assign to m_functionDeclaration->body() because UserFunction can apply
          * to several different callsites. Hence we need our own version. */
         m_body = m_body->typeCheck(context, reqType);
 
         /* We just act as a pipe for m_body, so we don't have to typecheck ourselves. However,
          * the arguments must match the function declaration. */
         typeCheckOperands(context);
         return Expression::Ptr(this);
     }
 }

Friends and Related Functions

◆ formatFunction()

static QString formatFunction ( const UserFunctionCallsite::Ptr & func )

Definition at line 166 of file quserfunctioncallsite_p.h.

     {
         Q_UNUSED(func);
         // TODO TODO TODO
         // TODO Make UserFunctionCallsite always use a FunctionSignature
         return QLatin1String("<span class='XQuery-function'>")  +
                QString() +
                //escape(func->name()->toString())                 +
                QLatin1String("</span>");
     }

Properties

◆ m_arity

const FunctionSignature::Arity QPatternist::UserFunctionCallsite::m_arity

private

Definition at line 145 of file quserfunctioncallsite_p.h.

Referenced by arity(), and isSignatureValid().

◆ m_body

Expression::Ptr QPatternist::UserFunctionCallsite::m_body

private

Note: This may be different from m_functionDeclaration->body(). It may differ on a per-callsite basis.

Definition at line 157 of file quserfunctioncallsite_p.h.

Referenced by body(), compress(), evaluateEBV(), evaluateSequence(), evaluateSingleton(), evaluateToSequenceReceiver(), setSource(), staticType(), and typeCheck().

◆ m_expressionSlotOffset

VariableSlotID QPatternist::UserFunctionCallsite::m_expressionSlotOffset

private

The reason this variable, as well as others, aren't const, is that the binding to the actual function, is resolved after this UserFunctionCallsite has been created.

Definition at line 151 of file quserfunctioncallsite_p.h.

Referenced by bindVariables(), and setSource().

◆ m_functionDeclaration

UserFunction::Ptr QPatternist::UserFunctionCallsite::m_functionDeclaration

private

Definition at line 158 of file quserfunctioncallsite_p.h.

Referenced by callTargetDescription(), expectedOperandTypes(), setSource(), and typeCheck().

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

/src/xmlpatterns/expr/quserfunctioncallsite_p.h
/src/xmlpatterns/expr/quserfunctioncallsite.cpp

Public Types

Public Functions

Private Functions

Properties

Related Functions

Additional Inherited Members

Detailed Description

Typedefs

◆ List

◆ Ptr

Constructors and Destructors

◆ UserFunctionCallsite()

Functions

◆ accept()

◆ arity()

◆ bindVariables()

◆ body()

◆ callTargetDescription()

◆ compress()

◆ configureRecursion()

◆ evaluateEBV()

◆ evaluateSequence()

◆ evaluateSingleton()

◆ evaluateToSequenceReceiver()

◆ expectedOperandTypes()

◆ id()

◆ isSignatureValid()

◆ properties()

◆ setSource()

◆ staticType()

◆ typeCheck()

Friends and Related Functions

◆ formatFunction()

Properties

◆ m_arity

◆ m_body

◆ m_expressionSlotOffset

◆ m_functionDeclaration