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    41 

    42 //

    43 //  W A R N I N G

    44 //  -------------

    45 //

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

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

    48 // version without notice, or even be removed.

    49 //

    50 // We mean it.

    51 

    52 

    53 #ifndef Patternist_FunctionFactory_H

    54 #define Patternist_FunctionFactory_H

    55 

    56 #include <QHash>

    57 #include <QSharedData>

    58 

    59 #include "qexpression_p.h"

    60 #include "qfunctionsignature_p.h"

    61 #include "qprimitives_p.h"

    62 #include "qxmlname.h"

    63 

    64 QT_BEGIN_HEADER

    65 

    66 QT_BEGIN_NAMESPACE

    67 

    68 namespace QPatternist

    69 {

    70 

    71     /**

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

    73      *

    74      * @ingroup Patternist_functions

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

    76      * and XPath 2.0 Functions and Operators</a>

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

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

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

    80      */

    81     class FunctionFactory : public QSharedData

    82     {

    83     public:

    84 

    85         typedef QExplicitlySharedDataPointer<FunctionFactory> Ptr;

    86         typedef QList<FunctionFactory::Ptr> List;

    87 

    88         virtual ~FunctionFactory();

    89 

    90         /**

    91          * Creates a function call implementation.

    92          *

    93          * A FunctionFactory represents a set of functions, which it

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

    95          * a FunctionFactory per namespace exists.

    96          *

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

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

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

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

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

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

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

   104          * @param arguments the function's operands

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

   106          * and reporting functionality.

   107          * @param r the SourceLocationReflection that identifies the callsite.

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

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

   110          */

   111         virtual Expression::Ptr createFunctionCall(const QXmlName name,

   112                                                    const Expression::List &arguments,

   113                                                    const StaticContext::Ptr &context,

   114                                                    const SourceLocationReflection *const r) = 0;

   115 

   116         /**

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

   118          * is available. The implementation operates on the result of

   119          * retrieveFunctionSignature() to determine the result.

   120          *

   121          * @param np the NamePool.

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

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

   124          */

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

   126                                  const QXmlName name,

   127                                  const xsInteger arity);

   128 

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

   130 

   131         /**

   132          * Determines whether this FunctionFactory contains the function signature

   133          * @p signature.

   134          *

   135          * The implementation uses functionSignatures().

   136          */

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

   138 

   139     protected:

   140         /**

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

   142          * some reason.

   143          */

   144         inline FunctionFactory()

   145         {

   146         }

   147 

   148         /**

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

   150          * function signature for function with name @p name.

   151          *

   152          * According to the specifications are function signatures identified by their

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

   154          *

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

   156          */

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

   158 

   159     private:

   160         Q_DISABLE_COPY(FunctionFactory)

   161     };

   162 }

   163 

   164 QT_END_NAMESPACE

   165 

   166 QT_END_HEADER

   167 

   168 #endif