pycallback.h

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/** @file
 *  @author Bram de Greve (bram@cocamware.com)
 *  @author Tom De Muer (tom@cocamware.com)
 *
 *  *** BEGIN LICENSE INFORMATION ***
 *  
 *  The contents of this file are subject to the Common Public Attribution License 
 *  Version 1.0 (the "License"); you may not use this file except in compliance with 
 *  the License. You may obtain a copy of the License at 
 *  http://lass.sourceforge.net/cpal-license. The License is based on the 
 *  Mozilla Public License Version 1.1 but Sections 14 and 15 have been added to cover 
 *  use of software over a computer network and provide for limited attribution for 
 *  the Original Developer. In addition, Exhibit A has been modified to be consistent 
 *  with Exhibit B.
 *  
 *  Software distributed under the License is distributed on an "AS IS" basis, WITHOUT 
 *  WARRANTY OF ANY KIND, either express or implied. See the License for the specific 
 *  language governing rights and limitations under the License.
 *  
 *  The Original Code is LASS - Library of Assembled Shared Sources.
 *  
 *  The Initial Developer of the Original Code is Bram de Greve and Tom De Muer.
 *  The Original Developer is the Initial Developer.
 *  
 *  All portions of the code written by the Initial Developer are:
 *  Copyright (C) 2004-2025 the Initial Developer.
 *  All Rights Reserved.
 *  
 *  Contributor(s):
 *
 *  Alternatively, the contents of this file may be used under the terms of the 
 *  GNU General Public License Version 2 or later (the GPL), in which case the 
 *  provisions of GPL are applicable instead of those above.  If you wish to allow use
 *  of your version of this file only under the terms of the GPL and not to allow 
 *  others to use your version of this file under the CPAL, indicate your decision by 
 *  deleting the provisions above and replace them with the notice and other 
 *  provisions required by the GPL License. If you do not delete the provisions above,
 *  a recipient may use your version of this file under either the CPAL or the GPL.
 *  
 *  *** END LICENSE INFORMATION ***
 */
 
#ifndef LASS_GUARDIAN_OF_INCLUSION_UTIL_PYCALLBACK_H
#define LASS_GUARDIAN_OF_INCLUSION_UTIL_PYCALLBACK_H
 
#include "python_common.h"
#include "pyshadow_object.h"
#include "pyiteratorrange.h"
#include "container.h"
#include "pyobject_util.h"
#include <map>
#include "../stde/access_iterator.h"
#include "../meta/type_traits.h"
 
#include "../util/multi_callback.h"
#include "callback_python.h"
 
namespace lass
{
namespace python
{
 
class MultiCallback;
 
namespace impl
{
 
    class LASS_PYTHON_DLL MultiCallbackImplBase
    {
    public:
        virtual ~MultiCallbackImplBase() {};
        virtual void reset() = 0;
        virtual Py_ssize_t length() const = 0;
        virtual const std::type_info& type() const = 0;
        virtual void* raw(bool writable) = 0;
        virtual void call(const python::TPyObjPtr& args, PyObject* self) = 0;
        virtual void add(const python::TPyObjPtr& args) = 0;
 
        const std::string repr() const;
    };
 
 
    template <typename Callback> 
    class MultiCallbackImpl : public MultiCallbackImplBase
    {
    public:
        typedef Callback TCallback;
        typedef util::SharedPtr<Callback> TCallbackPtr;
        typedef util::SharedPtr<const Callback> TConstCallbackPtr;
    
        MultiCallbackImpl( const TCallbackPtr & callback, bool readonly) : callback_(callback), readOnly_(readonly)
        {
        }
 
        void reset() override { return callback_->reset(); }                                    // move to traits class, to discern multi and non-multi
        Py_ssize_t length() const override { return static_cast<Py_ssize_t>(callback_->size()); };              // move to traits class, to discern multi and non-multi
 
        const std::type_info& type() const override
        { 
            return typeid(TCallbackPtr); 
        }
        void* raw(bool writable) override
        { 
            if (writable && readOnly_)
            {
                return 0;
            }
            return &callback_; 
        }
        void call(const python::TPyObjPtr& args, PyObject* self) override;
        void add(const python::TPyObjPtr& args) override
        {
            // the "thing" we add must be convertible to a callback
            // [TODO] use a decodeTuple
            LockGIL LASS_UNUSED(lock);
            Callback tempCallback;
            if (args.get() && PyTuple_Check(args.get()) && PyTuple_Size(args.get())==1)
            {
                Py_XINCREF(args.get());
                Py_XINCREF(PyTuple_GetItem(args.get(),0));
                int rv = pyGetSimpleObject(PyTuple_GetItem(args.get(),0),tempCallback);
                if (rv)
                {
                    impl::fetchAndThrowPythonException(LASS_PRETTY_FUNCTION);
                }
                for (size_t i=0;i<tempCallback.size();++i)
                    callback_->add(tempCallback[i]);
            }
        }
    protected:
        TCallbackPtr callback_;
        bool readOnly_;
    };
}
 
 
 
class MultiCallback;
typedef PyObjectPtr<MultiCallback>::Type TMultiCallbackPtr;
 
/** MultiCallback.  Object for interfacing MultiCallbacks with Python 
*/
class LASS_PYTHON_DLL MultiCallback : public PyObjectPlus, util::NonCopyable
{
    PY_HEADER(PyObjectPlus)
public:
    template <typename CallbackType> MultiCallback( const util::SharedPtr<CallbackType>& callback)
    {
        // [TODO] untested
        LASS_THROW("unsupported");
        TPimpl pimpl(
            new impl::MultiCallbackImpl<CallbackType>(callback,false));
        init(std::move(pimpl));
    }
    template <typename CallbackType> MultiCallback( const util::SharedPtr<const CallbackType>& /*callback*/)
    {
        // [TODO] untested
        LASS_THROW("unsupported");
        /*TPimpl pimpl(
            new impl::MultiCallbackImpl<CallbackType>(p,true));
        init(pimpl);*/
    }
    template<typename CallbackType> MultiCallback( const CallbackType& callback )
    {
        util::SharedPtr<CallbackType> p(new CallbackType(callback));
#pragma LASS_FIXME("This should be the read-only version")
        TPimpl pimpl(new impl::MultiCallbackImpl<CallbackType>(p,false));
        init(std::move(pimpl));
    }
    ~MultiCallback();
 
    std::string repr(void) const;
    void reset();
 
    void call(const python::TPyObjPtr& args);
    void add(const python::TPyObjPtr& args);
    PyObject* callVar(PyObject* args);
    PyObject* addVar(PyObject* args);
 
    static Py_ssize_t length(PyObject* self);
 
    const std::type_info& type() const;
    void* raw(bool writable) const;
 
    static PyObject* _tp_call(PyObject*, PyObject*, PyObject*);
 
private:
 
    typedef std::unique_ptr<impl::MultiCallbackImplBase> TPimpl; 
 
    MultiCallback(TPimpl&& pimpl);
    void init(TPimpl&& pimpl);
 
    TPimpl pimpl_;
};
 
namespace impl
{
    template <typename Callback>
    struct CallIntermediateShadowTraits
    {
        typedef Callback TCallback;
        typedef const Callback* TConstCallbackPtr;
 
        typedef TCallback TCppClass;
        typedef TConstCallbackPtr TConstCppClassPtr;
 
        static int getObject(PyObject* self, TConstCppClassPtr& forCalling)
        {
            lass::util::SharedPtr<TCallback>* almost = static_cast<lass::util::SharedPtr<TCallback>*>(static_cast<MultiCallback*>(self)->raw(false));
            forCalling = almost->get();
            return 0;
        }
    };
 
    template <typename C>
    void MultiCallbackImpl<C>::call(const python::TPyObjPtr& args, PyObject* self)
    {
        LockGIL LASS_UNUSED(lock); // as we're going to release it again ...
        impl::CallMethod< CallIntermediateShadowTraits<C> >::call(args.get(), self, &C::call ); 
    }
}
 
}
}
 
#include "pycallback_export_traits.inl"
 
#endif
 
// EOF