pyObjWrapper.h

//
// Copyright 2016 Pixar
//
// Licensed under the terms set forth in the LICENSE.txt file available at
// https://openusd.org/license.
//
#ifndef PXR_BASE_TF_PY_OBJ_WRAPPER_H
#define PXR_BASE_TF_PY_OBJ_WRAPPER_H
 
#include "pxr/pxr.h"
 
#include "pxr/base/tf/api.h"
#include "pxr/base/arch/pragmas.h"
 
#ifdef PXR_PYTHON_SUPPORT_ENABLED
// Include this header first to pick up additional mitigations
// for build issues when including Python.h
#include "pxr/base/tf/pySafePython.h"
 
#include <boost/functional/hash.hpp>
#include <boost/python/object_fwd.hpp>
#include <boost/python/object_operators.hpp>
 
#include <iosfwd>
#include <memory>
 
#else
 
#include <type_traits>
 
#endif
 
PXR_NAMESPACE_OPEN_SCOPE
 
// We define the empty stub for ABI compatibility even if Python support is
// enabled so we can make sure size and alignment is the same.
class TfPyObjWrapperStub
{
public:
    static constexpr std::size_t Size = 16;
    static constexpr std::size_t Align = 8;
 
private:
    ARCH_PRAGMA_PUSH
    ARCH_PRAGMA_UNUSED_PRIVATE_FIELD
    std::aligned_storage<Size, Align>::type _stub;
    ARCH_PRAGMA_POP
};
 
 
#ifdef PXR_PYTHON_SUPPORT_ENABLED
class TfPyObjWrapper
    : public boost::python::api::object_operators<TfPyObjWrapper>
{
    typedef boost::python::object object;
 
public:
 
    TF_API TfPyObjWrapper();
 
    TF_API TfPyObjWrapper(object obj);
 
    object const &Get() const {
        return *_objectPtr;
    }
 
    TF_API PyObject *ptr() const;
 
    friend inline size_t hash_value(TfPyObjWrapper const &o) {
        return (size_t) o.ptr();
    }
 
    TF_API bool operator==(TfPyObjWrapper const &other) const;
 
    TF_API bool operator!=(TfPyObjWrapper const &other) const;
 
private:
 
    // Befriend object_operators to allow it access to implicit conversion to
    // boost::python::object.
    friend class boost::python::api::object_operators<TfPyObjWrapper>;
    operator object const &() const {
        return Get();
    }
 
    // Store a shared_ptr to a python object.
    std::shared_ptr<object> _objectPtr;
};
 
static_assert(sizeof(TfPyObjWrapper) == sizeof(TfPyObjWrapperStub),
              "ABI break: Incompatible class sizes.");
static_assert(alignof(TfPyObjWrapper) == alignof(TfPyObjWrapperStub),
              "ABI break: Incompatible class alignments.");
 
#else // PXR_PYTHON_SUPPORT_ENABLED
 
class TfPyObjWrapper : TfPyObjWrapperStub
{
};
 
#endif // PXR_PYTHON_SUPPORT_ENABLED
 
PXR_NAMESPACE_CLOSE_SCOPE
 
#endif // PXR_BASE_TF_PY_OBJ_WRAPPER_H