ExtensionModule.hxx

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#ifndef __CXX_ExtensionModule__h
#define __CXX_ExtensionModule__h

namespace Py
{
    class ExtensionModuleBase
    {
    public:
        ExtensionModuleBase( const char *name );
        virtual ~ExtensionModuleBase();

        Module module( void ) const;            // only valid after initialize() has been called
        Dict moduleDictionary( void ) const;    // only valid after initialize() has been called

        virtual Object invoke_method_noargs( void *method_def ) = 0;
        virtual Object invoke_method_keyword( void *method_def, const Tuple &_args, const Dict &_keywords ) = 0;
        virtual Object invoke_method_varargs( void *method_def, const Tuple &_args ) = 0;

        const std::string &name() const;
        const std::string &fullName() const;

        // what is returned from PyInit_<module> function
        Object moduleObject( void ) const;

    protected:
        // Initialize the module
        void initialize( const char *module_doc );

        const std::string m_module_name;
        const std::string m_full_module_name;
        MethodTable m_method_table;
        PyObject *m_module;

    private:
        //
        // prevent the compiler generating these unwanted functions
        //
        ExtensionModuleBase( const ExtensionModuleBase & );     //unimplemented
        void operator=( const ExtensionModuleBase & );          //unimplemented
    };

    // Note: Python calls noargs as varargs buts args==NULL
    extern "C" PyObject *method_noargs_call_handler( PyObject *_self_and_name_tuple, PyObject * );
    extern "C" PyObject *method_varargs_call_handler( PyObject *_self_and_name_tuple, PyObject *_args );
    extern "C" PyObject *method_keyword_call_handler( PyObject *_self_and_name_tuple, PyObject *_args, PyObject *_keywords );

    extern "C" void do_not_dealloc( void * );

    template<TEMPLATE_TYPENAME T>
    class ExtensionModule : public ExtensionModuleBase
    {
    public:
        ExtensionModule( const char *name )
        : ExtensionModuleBase( name )
        {}
        virtual ~ExtensionModule()
        {}

    protected:
        typedef Object (T::*method_noargs_function_t)();
        typedef Object (T::*method_varargs_function_t)( const Tuple &args );
        typedef Object (T::*method_keyword_function_t)( const Tuple &args, const Dict &kws );
        typedef std::map<std::string, MethodDefExt<T> *> method_map_t;

        static void add_noargs_method( const char *name, method_noargs_function_t function, const char *doc="" )
        {
            method_map_t &mm = methods();
            mm[ std::string( name ) ] = new MethodDefExt<T>( name, function, method_noargs_call_handler, doc );
        }

        static void add_varargs_method( const char *name, method_varargs_function_t function, const char *doc="" )
        {
            method_map_t &mm = methods();
            mm[ std::string( name ) ] = new MethodDefExt<T>( name, function, method_varargs_call_handler, doc );
        }

        static void add_keyword_method( const char *name, method_keyword_function_t function, const char *doc="" )
        {
            method_map_t &mm = methods();
            mm[ std::string( name ) ] = new MethodDefExt<T>( name, function, method_keyword_call_handler, doc );
        }

        void initialize( const char *module_doc="" )
        {
            ExtensionModuleBase::initialize( module_doc );
            Dict dict( moduleDictionary() );

            //
            // put each of the methods into the modules dictionary
            // so that we get called back at the function in T.
            //
            method_map_t &mm = methods();
            EXPLICIT_TYPENAME method_map_t::const_iterator i = mm.begin();
            EXPLICIT_TYPENAME method_map_t::const_iterator i_end = mm.end();
            for ( ; i != i_end; ++i )
            {
                MethodDefExt<T> *method_def = (*i).second;

                static PyObject *self = PyCObject_FromVoidPtr( this, do_not_dealloc );

                Tuple args( 2 );
                args[0] = Object( self, true );
                args[1] = Object( PyCObject_FromVoidPtr( method_def, do_not_dealloc ), true );

                PyObject *func = PyCFunction_New
                                    (
                                    &method_def->ext_meth_def,
                                    new_reference_to( args )
                                    );

                method_def->py_method = Object( func, true );

                dict[ (*i).first ] = method_def->py_method;
            }
        }

    protected:    // Tom Malcolmson reports that derived classes need access to these
        static method_map_t &methods( void )
        {
            static method_map_t *map_of_methods = NULL;
            if( map_of_methods == NULL )
                map_of_methods = new method_map_t;

            return *map_of_methods;
        }

        // this invoke function must be called from within a try catch block
        virtual Object invoke_method_noargs( void *method_def )
        {
            // cast up to the derived class, method_def and call
            T *self = static_cast<T *>( this );
            MethodDefExt<T> *meth_def = reinterpret_cast<MethodDefExt<T> *>( method_def );

            return (self->*meth_def->ext_noargs_function)();
        }

        // this invoke function must be called from within a try catch block
        virtual Object invoke_method_varargs( void *method_def, const Tuple &args )
        {
            // cast up to the derived class, method_def and call
            T *self = static_cast<T *>( this );
            MethodDefExt<T> *meth_def = reinterpret_cast<MethodDefExt<T> *>( method_def );

            return (self->*meth_def->ext_varargs_function)( args );
        }

        // this invoke function must be called from within a try catch block
        virtual Object invoke_method_keyword( void *method_def, const Tuple &args, const Dict &keywords )
        {
            // cast up to the derived class, method_def and call
            T *self = static_cast<T *>( this );
            MethodDefExt<T> *meth_def = reinterpret_cast<MethodDefExt<T> *>( method_def );

            return (self->*meth_def->ext_keyword_function)( args, keywords );
        }

    private:
        //
        // prevent the compiler generating these unwanted functions
        //
        ExtensionModule( const ExtensionModule<T> & );  //unimplemented
        void operator=( const ExtensionModule<T> & );   //unimplemented
    };
} // Namespace Py


// End of __CXX_ExtensionModule__h
#endif