Add support for multi-phase module initialization

Author: o01eg

include/boost/python/module.hpp

@@ -9,5 +9,8 @@
 
 # include <boost/python/module_init.hpp>
 # define BOOST_PYTHON_MODULE BOOST_PYTHON_MODULE_INIT
+# if PY_VERSION_HEX >= 0x03050000
+#  define BOOST_PYTHON_MODULE_MULTI_PHASE BOOST_PYTHON_MODULE_MULTI_PHASE_INIT
+# endif
 
 #endif // MODULE_DWA20011221_HPP

include/boost/python/module_init.hpp

@@ -47,6 +47,12 @@ namespace detail {
 
 BOOST_PYTHON_DECL PyObject* init_module(PyModuleDef&, void(*)(), bool gil_not_used = false);
 
+#   if PY_VERSION_HEX >= 0x03050000
+
+BOOST_PYTHON_DECL int exec_module(PyObject*, void(*)());
+
+#   endif
+
 #else
 
 BOOST_PYTHON_DECL PyObject* init_module(char const* name, void(*)());
@@ -115,6 +121,46 @@ BOOST_PYTHON_DECL PyObject* init_module(char const* name, void(*)());
   void BOOST_PP_CAT(init_module_, name)()
 #   endif // HAS_CXX11
 
+#   if PY_VERSION_HEX >= 0x03050000
+
+#    define _BOOST_PYTHON_MODULE_MULTI_PHASE_INIT(name) \
+  int BOOST_PP_CAT(exec_module_,name)(PyObject* module) \
+  { \
+    return boost::python::detail::exec_module( \
+        module, BOOST_PP_CAT(init_module_, name) ); \
+  } \
+  extern "C" BOOST_SYMBOL_EXPORT PyObject* BOOST_PP_CAT(PyInit_, name)()  \
+  { \
+    static PyModuleDef_Base initial_m_base = { \
+        PyObject_HEAD_INIT(NULL) \
+        0, /* m_init */ \
+        0, /* m_index */ \
+        0 /* m_copy */ };  \
+    static PyMethodDef initial_methods[] = { { 0, 0, 0, 0 } }; \
+ \
+    static PyModuleDef_Slot slots[] = { \
+        {Py_mod_exec, reinterpret_cast<void*>(reinterpret_cast<uintptr_t>(BOOST_PP_CAT(exec_module_, name)))}, \
+        {0, NULL} \
+    }; \
+ \
+    static struct PyModuleDef moduledef = { \
+        initial_m_base, \
+        BOOST_PP_STRINGIZE(name), \
+        0, /* m_doc */ \
+        0, /* m_size */ \
+        initial_methods, \
+        slots,  /* m_slots */ \
+        0, /* m_traverse */ \
+        0, /* m_clear */ \
+        0,  /* m_free */ \
+    }; \
+ \
+    return PyModuleDef_Init(&moduledef); \
+  } \
+  void BOOST_PP_CAT(init_module_, name)()
+
+#   endif
+
 #  else
 
 #   define _BOOST_PYTHON_MODULE_INIT(name)              \
@@ -137,6 +183,14 @@ extern "C" BOOST_SYMBOL_EXPORT _BOOST_PYTHON_MODULE_INIT(name, __VA_ARGS__)
 extern "C" BOOST_SYMBOL_EXPORT _BOOST_PYTHON_MODULE_INIT(name)
 #  endif // HAS_CXX11 && Python 3
 
+#  if PY_VERSION_HEX >= 0x03050000
+
+#   define BOOST_PYTHON_MODULE_MULTI_PHASE_INIT(name)          \
+  void BOOST_PP_CAT(init_module_,name)();                      \
+extern "C" BOOST_SYMBOL_EXPORT _BOOST_PYTHON_MODULE_MULTI_PHASE_INIT(name)
+
+#  endif
+
 # endif
 
 #endif // MODULE_INIT_DWA20020722_HPP

src/module.cpp

@@ -52,6 +52,18 @@ BOOST_PYTHON_DECL PyObject* init_module(PyModuleDef& moduledef,
         init_function);
 }
 
+# if PY_VERSION_HEX >= 0x03050000
+
+BOOST_PYTHON_DECL int exec_module(PyObject* module, void(*init_function)())
+{
+    PyObject* retval = init_module_in_scope(
+        module,
+        init_function);
+    return retval ? 0 : -1;
+}
+
+# endif
+
 #else
 
 namespace

test/fabscript

@@ -174,4 +174,9 @@ for t in ['numpy/dtype',
     tests.append(extension_test(t, numpy=True,
                                 condition=set.define.contains('HAS_NUMPY')))
 
+python_version_major, python_version_minor = map(int, python.instance().version.split('.')[:2])
+
+tests.append(extension_test("module_multi_phase",
+                            condition=python_version_major > 3 or (python_version_major == 3 and python_version_minor >= 5)))
+
 default = report('report', tests, fail_on_failures=True)

test/module_multi_phase.cpp

@@ -0,0 +1,15 @@
+// Distributed under the Boost Software License, Version 1.0. (See
+// accompanying file LICENSE_1_0.txt or copy at
+// http://www.boost.org/LICENSE_1_0.txt)
+
+#include <boost/python/module.hpp>
+#include <boost/python/scope.hpp>
+
+using namespace boost::python;
+
+BOOST_PYTHON_MODULE_MULTI_PHASE(module_multi_phase_ext)
+{
+    scope().attr("x") = "x";
+}
+
+#include "module_tail.cpp"

test/module_multi_phase.py

@@ -0,0 +1,23 @@
+# Distributed under the Boost
+# Software License, Version 1.0. (See accompanying
+# file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+"""
+>>> import module_multi_phase_ext
+>>> module_multi_phase_ext.x
+'x'
+"""
+
+def run(args = None):
+    import sys
+    import doctest
+
+    if args is not None:
+        sys.argv = args
+    return doctest.testmod(sys.modules.get(__name__))
+
+if __name__ == '__main__':
+    print("running...")
+    import sys
+    status = run()[0]
+    if (status == 0): print("Done.")
+    sys.exit(status)