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//

//  W A R N I N G

//  -------------

//

// This file is not part of the Qt API.  It exists purely as an

// implementation detail.  This header file may change from version to

// version without notice, or even be removed.

//

// We mean it.

#ifndef Patternist_FunctionFactory_H

#define Patternist_FunctionFactory_H

#include <QHash>

#include <QSharedData>

#include "qexpression_p.h"

#include "qfunctionsignature_p.h"

#include "qprimitives_p.h"

#include "qxmlname.h"

QT_BEGIN_HEADER

QT_BEGIN_NAMESPACE

namespace QPatternist

{

    /**

     * @short An entry point for looking up and creating FunctionCall instances.

     *

     * @ingroup Patternist_functions

     * @see <a href ="http://www.w3.org/TR/xpath-functions/">XQuery 1.0

     * and XPath 2.0 Functions and Operators</a>

     * @see <a href="http://www.w3.org/TR/xpath20/#dt-function-signature">XML Path

     * Language (XPath) 2.0, Definition: Function signatures</a>

     * @author Frans Englich <frans.englich@nokia.com>

     */

    class FunctionFactory : public QSharedData

    {

    public:

        typedef QExplicitlySharedDataPointer<FunctionFactory> Ptr;

        typedef QList<FunctionFactory::Ptr> List;

        virtual ~FunctionFactory();

        /**

         * Creates a function call implementation.

         *

         * A FunctionFactory represents a set of functions, which it

         * is able to instantiate and to serve FunctionSignatures for. Conventionally,

         * a FunctionFactory per namespace exists.

         *

         * @note This function should not issue any error unless it is absolutely

         * confident that the error cannot be fixed in another way. For example, in

         * some cases it might be that a function is available in another FunctionFactory

         * and it would therefore be wrong to issue an error signalling that no function

         * by that @p name exists, but leave that to the callee.

         * @param name the name of the function to create. In Clark syntax, this could

         * for example be {http://www.w3.org/2005/04/xpath-functions}lower-case

         * @param arguments the function's operands

         * @param context the usual StaticContext which supplies compile time data

         * and reporting functionality.

         * @param r the SourceLocationReflection that identifies the callsite.

         * @returns an instance of Expression which is the function implementation

         * for @p name. Or, a static error was raised.

         */

        virtual Expression::Ptr createFunctionCall(const QXmlName name,

                                                   const Expression::List &arguments,

                                                   const StaticContext::Ptr &context,

                                                   const SourceLocationReflection *const r) = 0;

        /**

         * Determines whether a function with the name @p name and arity @p arity

         * is available. The implementation operates on the result of

         * retrieveFunctionSignature() to determine the result.

         *

         * @param np the NamePool.

         * @param name the name of the function. For example fn:string-join.

         * @param arity the number of arguments the function must have.

         */

        virtual bool isAvailable(const NamePool::Ptr &np,

                                 const QXmlName name,

                                 const xsInteger arity);

        virtual FunctionSignature::Hash functionSignatures() const = 0;

        /**

         * Determines whether this FunctionFactory contains the function signature

         * @p signature.

         *

         * The implementation uses functionSignatures().

         */

        bool hasSignature(const FunctionSignature::Ptr &signature) const;

    protected:

        /**

         * @short This constructor cannot be removed, because it can't be synthesized, for

         * some reason.

         */

        inline FunctionFactory()

        {

        }

        /**

         * This is a convenience function for sub-classes. It retrieves the

         * function signature for function with name @p name.

         *

         * According to the specifications are function signatures identified by their

         * name and arity, but currently is the arity not part of the signature.

         *

         * If no function could be found for the given name, @c null is returned.

         */

        virtual FunctionSignature::Ptr retrieveFunctionSignature(const NamePool::Ptr &np, const QXmlName name) = 0;

    private:

        Q_DISABLE_COPY(FunctionFactory)

    };

}

QT_END_NAMESPACE

QT_END_HEADER

#endif