Extensions.h

//---------------------------------------------------------------------------//
// Copyright 1998 The Regents of the University of California. 
// All rights reserved. See LEGAL.LLNL for full text and disclaimer.
//---------------------------------------------------------------------------//
 
#ifndef __CXX_Extensions__h
#define __CXX_Extensions__h
 
 
#ifdef _MSC_VER
// disable warning C4786: symbol greater than 255 character,
// okay to ignore
#pragma warning(disable: 4786)
#endif
 
 
#include "Config.h"
#include "Objects.h"
 
extern "C"
    {
    extern PyObject py_object_initializer;
    }
 
#include <vector>
#include <map>
 
namespace Py
    {
    class ExtensionModuleBase;
    
    // Make an Exception Type for use in raising custom exceptions
    class ExtensionExceptionType : public Object
        {
    public:
        ExtensionExceptionType();
        virtual ~ExtensionExceptionType();
 
        // call init to create the type
        void init(  ExtensionModuleBase &module, const std::string& name );
        };
 
    
    class MethodTable 
        {
    public:
        MethodTable();
        virtual ~MethodTable();
        
        void add(const char* method_name, PyCFunction f, const char* doc="", int flag=1);
        PyMethodDef* table();
        
    protected:
        std::vector<PyMethodDef> t; // accumulator of PyMethodDef's
        PyMethodDef *mt;        // Actual method table produced when full
        
        static PyMethodDef method (const char* method_name, PyCFunction f, int flags = 1, const char* doc="");
        
    private:
        //
        // prevent the compiler generating these unwanted functions
        //
        MethodTable(const MethodTable& m);  //unimplemented
        void operator=(const MethodTable& m);   //unimplemented
        
        }; // end class MethodTable
    
    extern "C"
        {
        typedef PyObject *(*method_varargs_call_handler_t)( PyObject *_self, PyObject *_args );
        typedef PyObject *(*method_keyword_call_handler_t)( PyObject *_self, PyObject *_args, PyObject *_dict );
        }
    
    template<class T>
    class MethodDefExt : public PyMethodDef
        {
    public:
        typedef Object (T::*method_varargs_function_t)( const Tuple &args );
        typedef Object (T::*method_keyword_function_t)( const Tuple &args, const Dict &kws );
        
        MethodDefExt
        (
        const char *_name,
        method_varargs_function_t _function,
        method_varargs_call_handler_t _handler,
        const char *_doc
        )
            {
            ext_meth_def.ml_name = const_cast<char *>(_name);
            ext_meth_def.ml_meth = _handler;
            ext_meth_def.ml_flags = METH_VARARGS;
            ext_meth_def.ml_doc = const_cast<char *>(_doc);
            
            ext_varargs_function = _function;
            ext_keyword_function = NULL;
            }
        
        MethodDefExt
        (
        const char *_name,
        method_keyword_function_t _function,
        method_keyword_call_handler_t _handler,
        const char *_doc
        )
            {
            ext_meth_def.ml_name = const_cast<char *>(_name);
            ext_meth_def.ml_meth = method_varargs_call_handler_t( _handler );
            ext_meth_def.ml_flags = METH_VARARGS|METH_KEYWORDS;
            ext_meth_def.ml_doc = const_cast<char *>(_doc);
            
            ext_varargs_function = NULL;
            ext_keyword_function = _function;
            }
        
        ~MethodDefExt()
            {}
        
        PyMethodDef ext_meth_def;
        method_varargs_function_t ext_varargs_function; 
        method_keyword_function_t ext_keyword_function; 
        };
    
    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_keyword( const std::string &_name, const Tuple &_args, const Dict &_keywords ) = 0;
        virtual Object invoke_method_varargs( const std::string &_name, const Tuple &_args ) = 0;
        
        const std::string &name() const;
        const std::string &fullName() const;
    
    protected:
        // Initialize the module
        void initialize( const char *module_doc );
        
        const std::string module_name;
        const std::string full_module_name;
        MethodTable method_table;
        
    private:
        
        //
        // prevent the compiler generating these unwanted functions
        //
        ExtensionModuleBase( const ExtensionModuleBase & ); //unimplemented
        void operator=( const ExtensionModuleBase & );      //unimplemented
        
        };
    
    extern "C" PyObject *method_keyword_call_handler( PyObject *_self_and_name_tuple, PyObject *_args, PyObject *_keywords );
    extern "C" PyObject *method_varargs_call_handler( PyObject *_self_and_name_tuple, PyObject *_args );
    extern "C" void do_not_dealloc( void * );
    
    
    template<typename T>
    class ExtensionModule : public ExtensionModuleBase
        {
    public:
        ExtensionModule( const char *name )
            : ExtensionModuleBase( name )
            {}
        virtual ~ExtensionModule()
            {}
        
    protected:
        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_varargs_method( const char *name, method_varargs_function_t function, const char *doc="" )
            {
            method_map_t &mm = methods();
            
            MethodDefExt<T> *method_definition = new MethodDefExt<T>
            (
            name,
            function,
            method_varargs_call_handler,
            doc
            );
            
            mm[std::string( name )] = method_definition;
            }
        
        static void add_keyword_method( const char *name, method_keyword_function_t function, const char *doc="" )
            {
            method_map_t &mm = methods();
            
            MethodDefExt<T> *method_definition = new MethodDefExt<T>
            (
            name,
            function,
            method_keyword_call_handler,
            doc
            );
            
            mm[std::string( name )] = method_definition;
            }
 
        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();
            typename method_map_t::iterator i;
            
            for( i=mm.begin(); i != mm.end(); ++i )
                {
                MethodDefExt<T> *method_definition = (*i).second;
                
                static PyObject *self = PyCObject_FromVoidPtr( this, do_not_dealloc );
                
                Tuple args( 2 );
                args[0] = Object( self );
                args[1] = String( (*i).first );
                
                PyObject *func = PyCFunction_New
                (
                &method_definition->ext_meth_def,
                new_reference_to( args )
                );
                
                dict[ (*i).first ] = Object( func );
                }
            }
        
    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_keyword( const std::string &name, const Tuple &args, const Dict &keywords )
            {
            method_map_t &mm = methods();
            MethodDefExt<T> *meth_def = mm[ name ];
            if( meth_def == NULL )
                {
                std::string error_msg( "CXX - cannot invoke keyword method named " );
                error_msg += name;
                throw RuntimeError( error_msg );
                }
            
            // cast up to the derived class
            T *self = static_cast<T *>(this);
            
            return (self->*meth_def->ext_keyword_function)( args, keywords );
            }
        
        // this invoke function must be called from within a try catch block
        virtual Object invoke_method_varargs( const std::string &name, const Tuple &args )
            {
            method_map_t &mm = methods();
            MethodDefExt<T> *meth_def = mm[ name ];
            if( meth_def == NULL )
                {
                std::string error_msg( "CXX - cannot invoke varargs method named " );
                error_msg += name;
                throw RuntimeError( error_msg );
                }
            
            // cast up to the derived class
            T *self = static_cast<T *>(this);
            
            return (self->*meth_def->ext_varargs_function)( args );
            }
        
    private:
        //
        // prevent the compiler generating these unwanted functions
        //
        ExtensionModule( const ExtensionModule<T> & );  //unimplemented
        void operator=( const ExtensionModule<T> & );   //unimplemented
        };
    
    
    class PythonType
        {
    public:
        // if you define one sequence method you must define 
        // all of them except the assigns
        
        PythonType (size_t base_size, int itemsize, const char *default_name );
        virtual ~PythonType ();
        
        const char *getName () const;
        const char *getDoc () const;
 
        PyTypeObject* type_object () const;
        void name (const char* nam);
        void doc (const char* d);
        void dealloc(void (*f)(PyObject*));
        
        void supportPrint(void);
        void supportGetattr(void);
        void supportSetattr(void);
        void supportGetattro(void);
        void supportSetattro(void);
        void supportCompare(void);
        void supportRepr(void);
        void supportStr(void);
        void supportHash(void);
        void supportCall(void);
        
        void supportSequenceType(void);
        void supportMappingType(void);
        void supportNumberType(void);
        void supportBufferType(void);
        
    protected:
        PyTypeObject        *table;
        PySequenceMethods   *sequence_table;
        PyMappingMethods    *mapping_table;
        PyNumberMethods     *number_table;
        PyBufferProcs       *buffer_table;
        
        void init_sequence();
        void init_mapping();
        void init_number();
        void init_buffer();
        
    private:
        //
        // prevent the compiler generating these unwanted functions
        //
        PythonType (const PythonType& tb);  // unimplemented
        void operator=(const PythonType& t);    // unimplemented
        
        }; // end of PythonType
    
    
    
    // Class PythonExtension is what you inherit from to create
    // a new Python extension type. You give your class itself
    // as the template paramter.
    
    // There are two ways that extension objects can get destroyed.
    // 1. Their reference count goes to zero
    // 2. Someone does an explicit delete on a pointer.
    // In (1) the problem is to get the destructor called 
    //        We register a special deallocator in the Python type object
    //        (see behaviors()) to do this.
    // In (2) there is no problem, the dtor gets called.
    
    // PythonExtension does not use the usual Python heap allocator, 
    // instead using new/delete. We do the setting of the type object
    // and reference count, usually done by PyObject_New, in the 
    // base class ctor.
    
    // This special deallocator does a delete on the pointer.
    
    
    class PythonExtensionBase : public PyObject
        {
    public:
        PythonExtensionBase();
        virtual ~PythonExtensionBase();
        
    public:
        virtual int print( FILE *, int );
        virtual Object getattr( const char * ) = 0;
        virtual int setattr( const char *, const Object & );
        virtual Object getattro( const Object & );
        virtual int setattro( const Object &, const Object & );
        virtual int compare( const Object & );
        virtual Object repr();
        virtual Object str();
        virtual long hash();
        virtual Object call( const Object &, const Object & );
        
        // Sequence methods
        virtual int sequence_length();
        virtual Object sequence_concat( const Object & );
        virtual Object sequence_repeat( int );
        virtual Object sequence_item( int );
        virtual Object sequence_slice( int, int );
        virtual int sequence_ass_item( int, const Object & );
        virtual int sequence_ass_slice( int, int, const Object & );
        
        // Mapping
        virtual int mapping_length();
        virtual Object mapping_subscript( const Object & );
        virtual int mapping_ass_subscript( const Object &, const Object & );
        
        // Number
        virtual int number_nonzero();
        virtual Object number_negative();
        virtual Object number_positive();
        virtual Object number_absolute();
        virtual Object number_invert();
        virtual Object number_int();
        virtual Object number_float();
        virtual Object number_long();
        virtual Object number_oct();
        virtual Object number_hex();
        virtual Object number_add( const Object & );
        virtual Object number_subtract( const Object & );
        virtual Object number_multiply( const Object & );
        virtual Object number_divide( const Object & );
        virtual Object number_remainder( const Object & );
        virtual Object number_divmod( const Object & );
        virtual Object number_lshift( const Object & );
        virtual Object number_rshift( const Object & );
        virtual Object number_and( const Object & );
        virtual Object number_xor( const Object & );
        virtual Object number_or( const Object & );
        virtual Object number_power( const Object &, const Object & );
        
        // Buffer
        virtual int buffer_getreadbuffer( int, void** );
        virtual int buffer_getwritebuffer( int, void** );
        virtual int buffer_getsegcount( int* );
        
    private:
        void missing_method( void );
        static PyObject *method_call_handler( PyObject *self, PyObject *args );
        };
    
    template<typename T>
    class PythonExtension: public PythonExtensionBase 
        {
    public:
        static PyTypeObject* type_object() 
            {
            return behaviors().type_object();
            }
        
        static int check( PyObject *p )
            {
            // is p like me?
            return p->ob_type == type_object();
            }
        
        static int check( const Object& ob )
            {
            return check( ob.ptr());
            }
        
        
        //
        // every object needs getattr implemented
        // to support methods
        //
        virtual Object getattr( const char *name )
            {
            return getattr_methods( name );
            }
        
    protected:
        explicit PythonExtension()
            : PythonExtensionBase()
            {
            #ifdef PyObject_INIT
            (void)PyObject_INIT( this, type_object() );
            #else
            ob_refcnt = 1;
            ob_type = type_object();
            #endif
            
            // every object must support getattr
            behaviors().supportGetattr();
            }
        
        virtual ~PythonExtension()
            {} 
        
        static PythonType &behaviors()
            {
            static PythonType* p;
            if( p == NULL ) 
                {
#if defined( _CPPRTTI )
                const char *default_name = (typeid ( T )).name();
#else
                const char *default_name = "unknown";
#endif
                p = new PythonType( sizeof( T ), 0, default_name );
                p->dealloc( extension_object_deallocator );
                }
            
            return *p;
            }
        
        
        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;
        
        // support the default attributes, __name__, __doc__ and methods
        virtual Object getattr_default( const char *_name )
            {
            std::string name( _name );
 
            if( name == "__name__" && type_object()->tp_name != NULL )
                {
                return Py::String( type_object()->tp_name );
                }
            else if( name == "__doc__" && type_object()->tp_doc != NULL )
                {
                return Py::String( type_object()->tp_doc );
                }
 
// trying to fake out being a class for help()
//          else if( name == "__bases__"  )
//              {
//              return Py::Tuple(0);
//              }
//          else if( name == "__module__"  )
//              {
//              return Py::Nothing();
//              }
//          else if( name == "__dict__"  )
//              {
//              return Py::Dict();
//              }
            else
                {
                return getattr_methods( _name );
                }
            }
 
        // turn a name into function object
        virtual Object getattr_methods( const char *_name )
            {
            std::string name( _name );
            
            method_map_t &mm = methods();
            
            if( name == "__methods__" )
                {
                List methods;
                
                for( typename method_map_t::iterator i = mm.begin(); i != mm.end(); ++i )
                    methods.append( String( (*i).first ) );
                
                return methods;
                }
            
            // see if name exists
            if( mm.find( name ) == mm.end() )
                throw AttributeError( "method '" + name + "' does not exist." );
            
            Tuple self( 2 );
            
            self[0] = Object( this );
            self[1] = String( name );
            
            MethodDefExt<T> *method_definition = mm[ name ];
            
            PyObject *func = PyCFunction_New( &method_definition->ext_meth_def, self.ptr() );
            
            return Object(func, true);
            }
        
        static void add_varargs_method( const char *name, method_varargs_function_t function, const char *doc="" )
            {
            method_map_t &mm = methods();
            
            MethodDefExt<T> *method_definition = new MethodDefExt<T>
            (
            name,
            function,
            method_varargs_call_handler,
            doc
            );
            
            mm[std::string( name )] = method_definition;
            }
        
        static void add_keyword_method( const char *name, method_keyword_function_t function, const char *doc="" )
            {
            method_map_t &mm = methods();
            
            MethodDefExt<T> *method_definition = new MethodDefExt<T>
            (
            name,
            function,
            method_keyword_call_handler,
            doc
            );
            
            mm[std::string( name )] = method_definition;
            }
        
    private:
        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;
            }
        
        static PyObject *method_keyword_call_handler( PyObject *_self_and_name_tuple, PyObject *_args, PyObject *_keywords )
            {
            try
                {
                Tuple self_and_name_tuple( _self_and_name_tuple );
                
                PyObject *self_in_cobject = self_and_name_tuple[0].ptr();
                T *self = static_cast<T *>( self_in_cobject );
                
                String name( self_and_name_tuple[1] );
                
                method_map_t &mm = methods();
                MethodDefExt<T> *meth_def = mm[ name ];
                if( meth_def == NULL )
                    return 0;
                
                Tuple args( _args );
 
                // _keywords may be NULL so be careful about the way the dict is created
                Dict keywords;
                if( _keywords != NULL )
                    keywords = Dict( _keywords );
                
                Object result( (self->*meth_def->ext_keyword_function)( args, keywords ) );
                
                return new_reference_to( result.ptr() );
                }
            catch( Exception & )
                {
                return 0;
                }
            }
        
        static PyObject *method_varargs_call_handler( PyObject *_self_and_name_tuple, PyObject *_args )
            {
            try
                {
                Tuple self_and_name_tuple( _self_and_name_tuple );
                
                PyObject *self_in_cobject = self_and_name_tuple[0].ptr();
                T *self = static_cast<T *>( self_in_cobject );
                
                String name( self_and_name_tuple[1] );
                
                method_map_t &mm = methods();
                MethodDefExt<T> *meth_def = mm[ name ];
                if( meth_def == NULL )
                    return 0;
                
                Tuple args( _args );
                
                Object result;
                
                // TMM: 7Jun'01 - Adding try & catch in case of STL debug-mode exceptions.
                #ifdef _STLP_DEBUG
                try
                    {
                    result = (self->*meth_def->ext_varargs_function)( args );
                    }
                catch (std::__stl_debug_exception)
                    {
                    // throw cxx::RuntimeError( sErrMsg );
                    throw cxx::RuntimeError( "Error message not set yet." );
                    }
                #else
                result = (self->*meth_def->ext_varargs_function)( args );
                #endif // _STLP_DEBUG
                
                return new_reference_to( result.ptr() );
                }
            catch( Exception & )
                {
                return 0;
                }
            }
        
        static void extension_object_deallocator ( PyObject* t )
            {
            delete (T *)( t );
            }
        
        //
        // prevent the compiler generating these unwanted functions
        //
        explicit PythonExtension( const PythonExtension<T>& other );
        void operator=( const PythonExtension<T>& rhs );
        };
    
    //
    // ExtensionObject<T> is an Object that will accept only T's.
    //
    template<typename T>
    class ExtensionObject: public Object
        {
    public:
        
        explicit ExtensionObject ( PyObject *pyob )
            : Object( pyob )
            {
            validate();
            }
        
        ExtensionObject( const ExtensionObject<T>& other )
            : Object( *other )
            {
            validate();
            }
        
        ExtensionObject( const Object& other )
            : Object( *other )
            {
            validate();
            }
        
        ExtensionObject& operator= ( const Object& rhs )
            {
            return (*this = *rhs );
            }
        
        ExtensionObject& operator= ( PyObject* rhsp )
            {
            if( ptr() == rhsp )
            return *this;
            set( rhsp );
            return *this;
            }
        
        virtual bool accepts ( PyObject *pyob ) const
            {
            return ( pyob && T::check( pyob ));
            }       
        
        //
        //  Obtain a pointer to the PythonExtension object
        //
        T *extensionObject(void)
            {
            return static_cast<T *>( ptr() );
            }
        };
    
    } // Namespace Py
// End of CXX_Extensions.h
#endif