api_implementation.cc

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// Protocol Buffers - Google's data interchange format
// Copyright 2008 Google Inc.  All rights reserved.
// https://developers.google.com/protocol-buffers/
//
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// modification, are permitted provided that the following conditions are
// met:
//
//     * Redistributions of source code must retain the above copyright
// notice, this list of conditions and the following disclaimer.
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// in the documentation and/or other materials provided with the
// distribution.
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// contributors may be used to endorse or promote products derived from
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//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
#include <Python.h>
 
namespace google {
namespace protobuf {
namespace python {
 
// Version constant.
// This is either 0 for python, 1 for CPP V1, 2 for CPP V2.
//
// 0 is default and is equivalent to
//   PROTOCOL_BUFFERS_PYTHON_IMPLEMENTATION=python
//
// 1 is set with -DPYTHON_PROTO2_CPP_IMPL_V1 and is equivalent to
//   PROTOCOL_BUFFERS_PYTHON_IMPLEMENTATION=cpp
// and
//   PROTOCOL_BUFFERS_PYTHON_IMPLEMENTATION_VERSION=1
//
// 2 is set with -DPYTHON_PROTO2_CPP_IMPL_V2 and is equivalent to
//   PROTOCOL_BUFFERS_PYTHON_IMPLEMENTATION=cpp
// and
//   PROTOCOL_BUFFERS_PYTHON_IMPLEMENTATION_VERSION=2
#ifdef PYTHON_PROTO2_CPP_IMPL_V1
#error "PYTHON_PROTO2_CPP_IMPL_V1 is no longer supported."
#else
#ifdef PYTHON_PROTO2_CPP_IMPL_V2
static int kImplVersion = 2;
#else
#ifdef PYTHON_PROTO2_PYTHON_IMPL
static int kImplVersion = 0;
#else
 
static int kImplVersion = -1;  // -1 means "Unspecified by compiler flags".
 
#endif  // PYTHON_PROTO2_PYTHON_IMPL
#endif  // PYTHON_PROTO2_CPP_IMPL_V2
#endif  // PYTHON_PROTO2_CPP_IMPL_V1
 
static const char* kImplVersionName = "api_version";
 
static const char* kModuleName = "_api_implementation";
static const char kModuleDocstring[] =
    "_api_implementation is a module that exposes compile-time constants that\n"
    "determine the default API implementation to use for Python proto2.\n"
    "\n"
    "It complements api_implementation.py by setting defaults using "
    "compile-time\n"
    "constants defined in C, such that one can set defaults at compilation\n"
    "(e.g. with blaze flag --copt=-DPYTHON_PROTO2_CPP_IMPL_V2).";
 
#if PY_MAJOR_VERSION >= 3
static struct PyModuleDef _module = {PyModuleDef_HEAD_INIT,
                                     kModuleName,
                                     kModuleDocstring,
                                     -1,
                                     NULL,
                                     NULL,
                                     NULL,
                                     NULL,
                                     NULL};
#define INITFUNC PyInit__api_implementation
#define INITFUNC_ERRORVAL NULL
#else
#define INITFUNC init_api_implementation
#define INITFUNC_ERRORVAL
#endif
 
extern "C" {
PyMODINIT_FUNC INITFUNC() {
#if PY_MAJOR_VERSION >= 3
  PyObject* module = PyModule_Create(&_module);
#else
  PyObject* module = Py_InitModule3(const_cast<char*>(kModuleName), NULL,
                                    const_cast<char*>(kModuleDocstring));
#endif
  if (module == NULL) {
    return INITFUNC_ERRORVAL;
  }
 
  // Adds the module variable "api_version".
  if (PyModule_AddIntConstant(module, const_cast<char*>(kImplVersionName),
                              kImplVersion))
#if PY_MAJOR_VERSION < 3
    return;
#else
  {
    Py_DECREF(module);
    return NULL;
  }
 
  return module;
#endif
}
}
 
}  // namespace python
}  // namespace protobuf
}  // namespace google