1 /*
2 pybind11/detail/class.h: Python C API implementation details for py::class_
3
4 Copyright (c) 2017 Wenzel Jakob <wenzel.jakob@epfl.ch>
5
6 All rights reserved. Use of this source code is governed by a
7 BSD-style license that can be found in the LICENSE file.
8 */
9
10 #pragma once
11
12 #include "../attr.h"
13
14 NAMESPACE_BEGIN(PYBIND11_NAMESPACE)
NAMESPACE_BEGIN(detail)15 NAMESPACE_BEGIN(detail)
16
17 #if PY_VERSION_HEX >= 0x03030000
18 # define PYBIND11_BUILTIN_QUALNAME
19 # define PYBIND11_SET_OLDPY_QUALNAME(obj, nameobj)
20 #else
21 // In pre-3.3 Python, we still set __qualname__ so that we can produce reliable function type
22 // signatures; in 3.3+ this macro expands to nothing:
23 # define PYBIND11_SET_OLDPY_QUALNAME(obj, nameobj) setattr((PyObject *) obj, "__qualname__", nameobj)
24 #endif
25
26 inline PyTypeObject *type_incref(PyTypeObject *type) {
27 Py_INCREF(type);
28 return type;
29 }
30
31 #if !defined(PYPY_VERSION)
32
33 /// `pybind11_static_property.__get__()`: Always pass the class instead of the instance.
pybind11_static_get(PyObject * self,PyObject *,PyObject * cls)34 extern "C" inline PyObject *pybind11_static_get(PyObject *self, PyObject * /*ob*/, PyObject *cls) {
35 return PyProperty_Type.tp_descr_get(self, cls, cls);
36 }
37
38 /// `pybind11_static_property.__set__()`: Just like the above `__get__()`.
pybind11_static_set(PyObject * self,PyObject * obj,PyObject * value)39 extern "C" inline int pybind11_static_set(PyObject *self, PyObject *obj, PyObject *value) {
40 PyObject *cls = PyType_Check(obj) ? obj : (PyObject *) Py_TYPE(obj);
41 return PyProperty_Type.tp_descr_set(self, cls, value);
42 }
43
44 /** A `static_property` is the same as a `property` but the `__get__()` and `__set__()`
45 methods are modified to always use the object type instead of a concrete instance.
46 Return value: New reference. */
make_static_property_type()47 inline PyTypeObject *make_static_property_type() {
48 constexpr auto *name = "pybind11_static_property";
49 auto name_obj = reinterpret_steal<object>(PYBIND11_FROM_STRING(name));
50
51 /* Danger zone: from now (and until PyType_Ready), make sure to
52 issue no Python C API calls which could potentially invoke the
53 garbage collector (the GC will call type_traverse(), which will in
54 turn find the newly constructed type in an invalid state) */
55 auto heap_type = (PyHeapTypeObject *) PyType_Type.tp_alloc(&PyType_Type, 0);
56 if (!heap_type)
57 pybind11_fail("make_static_property_type(): error allocating type!");
58
59 heap_type->ht_name = name_obj.inc_ref().ptr();
60 #ifdef PYBIND11_BUILTIN_QUALNAME
61 heap_type->ht_qualname = name_obj.inc_ref().ptr();
62 #endif
63
64 auto type = &heap_type->ht_type;
65 type->tp_name = name;
66 type->tp_base = type_incref(&PyProperty_Type);
67 type->tp_flags = Py_TPFLAGS_DEFAULT | Py_TPFLAGS_BASETYPE | Py_TPFLAGS_HEAPTYPE;
68 type->tp_descr_get = pybind11_static_get;
69 type->tp_descr_set = pybind11_static_set;
70
71 if (PyType_Ready(type) < 0)
72 pybind11_fail("make_static_property_type(): failure in PyType_Ready()!");
73
74 setattr((PyObject *) type, "__module__", str("pybind11_builtins"));
75 PYBIND11_SET_OLDPY_QUALNAME(type, name_obj);
76
77 return type;
78 }
79
80 #else // PYPY
81
82 /** PyPy has some issues with the above C API, so we evaluate Python code instead.
83 This function will only be called once so performance isn't really a concern.
84 Return value: New reference. */
make_static_property_type()85 inline PyTypeObject *make_static_property_type() {
86 auto d = dict();
87 PyObject *result = PyRun_String(R"(\
88 class pybind11_static_property(property):
89 def __get__(self, obj, cls):
90 return property.__get__(self, cls, cls)
91
92 def __set__(self, obj, value):
93 cls = obj if isinstance(obj, type) else type(obj)
94 property.__set__(self, cls, value)
95 )", Py_file_input, d.ptr(), d.ptr()
96 );
97 if (result == nullptr)
98 throw error_already_set();
99 Py_DECREF(result);
100 return (PyTypeObject *) d["pybind11_static_property"].cast<object>().release().ptr();
101 }
102
103 #endif // PYPY
104
105 /** Types with static properties need to handle `Type.static_prop = x` in a specific way.
106 By default, Python replaces the `static_property` itself, but for wrapped C++ types
107 we need to call `static_property.__set__()` in order to propagate the new value to
108 the underlying C++ data structure. */
pybind11_meta_setattro(PyObject * obj,PyObject * name,PyObject * value)109 extern "C" inline int pybind11_meta_setattro(PyObject* obj, PyObject* name, PyObject* value) {
110 // Use `_PyType_Lookup()` instead of `PyObject_GetAttr()` in order to get the raw
111 // descriptor (`property`) instead of calling `tp_descr_get` (`property.__get__()`).
112 PyObject *descr = _PyType_Lookup((PyTypeObject *) obj, name);
113
114 // The following assignment combinations are possible:
115 // 1. `Type.static_prop = value` --> descr_set: `Type.static_prop.__set__(value)`
116 // 2. `Type.static_prop = other_static_prop` --> setattro: replace existing `static_prop`
117 // 3. `Type.regular_attribute = value` --> setattro: regular attribute assignment
118 const auto static_prop = (PyObject *) get_internals().static_property_type;
119 const auto call_descr_set = descr && PyObject_IsInstance(descr, static_prop)
120 && !PyObject_IsInstance(value, static_prop);
121 if (call_descr_set) {
122 // Call `static_property.__set__()` instead of replacing the `static_property`.
123 #if !defined(PYPY_VERSION)
124 return Py_TYPE(descr)->tp_descr_set(descr, obj, value);
125 #else
126 if (PyObject *result = PyObject_CallMethod(descr, "__set__", "OO", obj, value)) {
127 Py_DECREF(result);
128 return 0;
129 } else {
130 return -1;
131 }
132 #endif
133 } else {
134 // Replace existing attribute.
135 return PyType_Type.tp_setattro(obj, name, value);
136 }
137 }
138
139 #if PY_MAJOR_VERSION >= 3
140 /**
141 * Python 3's PyInstanceMethod_Type hides itself via its tp_descr_get, which prevents aliasing
142 * methods via cls.attr("m2") = cls.attr("m1"): instead the tp_descr_get returns a plain function,
143 * when called on a class, or a PyMethod, when called on an instance. Override that behaviour here
144 * to do a special case bypass for PyInstanceMethod_Types.
145 */
pybind11_meta_getattro(PyObject * obj,PyObject * name)146 extern "C" inline PyObject *pybind11_meta_getattro(PyObject *obj, PyObject *name) {
147 PyObject *descr = _PyType_Lookup((PyTypeObject *) obj, name);
148 if (descr && PyInstanceMethod_Check(descr)) {
149 Py_INCREF(descr);
150 return descr;
151 }
152 else {
153 return PyType_Type.tp_getattro(obj, name);
154 }
155 }
156 #endif
157
158 /** This metaclass is assigned by default to all pybind11 types and is required in order
159 for static properties to function correctly. Users may override this using `py::metaclass`.
160 Return value: New reference. */
make_default_metaclass()161 inline PyTypeObject* make_default_metaclass() {
162 constexpr auto *name = "pybind11_type";
163 auto name_obj = reinterpret_steal<object>(PYBIND11_FROM_STRING(name));
164
165 /* Danger zone: from now (and until PyType_Ready), make sure to
166 issue no Python C API calls which could potentially invoke the
167 garbage collector (the GC will call type_traverse(), which will in
168 turn find the newly constructed type in an invalid state) */
169 auto heap_type = (PyHeapTypeObject *) PyType_Type.tp_alloc(&PyType_Type, 0);
170 if (!heap_type)
171 pybind11_fail("make_default_metaclass(): error allocating metaclass!");
172
173 heap_type->ht_name = name_obj.inc_ref().ptr();
174 #ifdef PYBIND11_BUILTIN_QUALNAME
175 heap_type->ht_qualname = name_obj.inc_ref().ptr();
176 #endif
177
178 auto type = &heap_type->ht_type;
179 type->tp_name = name;
180 type->tp_base = type_incref(&PyType_Type);
181 type->tp_flags = Py_TPFLAGS_DEFAULT | Py_TPFLAGS_BASETYPE | Py_TPFLAGS_HEAPTYPE;
182
183 type->tp_setattro = pybind11_meta_setattro;
184 #if PY_MAJOR_VERSION >= 3
185 type->tp_getattro = pybind11_meta_getattro;
186 #endif
187
188 if (PyType_Ready(type) < 0)
189 pybind11_fail("make_default_metaclass(): failure in PyType_Ready()!");
190
191 setattr((PyObject *) type, "__module__", str("pybind11_builtins"));
192 PYBIND11_SET_OLDPY_QUALNAME(type, name_obj);
193
194 return type;
195 }
196
197 /// For multiple inheritance types we need to recursively register/deregister base pointers for any
198 /// base classes with pointers that are difference from the instance value pointer so that we can
199 /// correctly recognize an offset base class pointer. This calls a function with any offset base ptrs.
traverse_offset_bases(void * valueptr,const detail::type_info * tinfo,instance * self,bool (* f)(void *,instance *))200 inline void traverse_offset_bases(void *valueptr, const detail::type_info *tinfo, instance *self,
201 bool (*f)(void * /*parentptr*/, instance * /*self*/)) {
202 for (handle h : reinterpret_borrow<tuple>(tinfo->type->tp_bases)) {
203 if (auto parent_tinfo = get_type_info((PyTypeObject *) h.ptr())) {
204 for (auto &c : parent_tinfo->implicit_casts) {
205 if (c.first == tinfo->cpptype) {
206 auto *parentptr = c.second(valueptr);
207 if (parentptr != valueptr)
208 f(parentptr, self);
209 traverse_offset_bases(parentptr, parent_tinfo, self, f);
210 break;
211 }
212 }
213 }
214 }
215 }
216
register_instance_impl(void * ptr,instance * self)217 inline bool register_instance_impl(void *ptr, instance *self) {
218 get_internals().registered_instances.emplace(ptr, self);
219 return true; // unused, but gives the same signature as the deregister func
220 }
deregister_instance_impl(void * ptr,instance * self)221 inline bool deregister_instance_impl(void *ptr, instance *self) {
222 auto ®istered_instances = get_internals().registered_instances;
223 auto range = registered_instances.equal_range(ptr);
224 for (auto it = range.first; it != range.second; ++it) {
225 if (Py_TYPE(self) == Py_TYPE(it->second)) {
226 registered_instances.erase(it);
227 return true;
228 }
229 }
230 return false;
231 }
232
register_instance(instance * self,void * valptr,const type_info * tinfo)233 inline void register_instance(instance *self, void *valptr, const type_info *tinfo) {
234 register_instance_impl(valptr, self);
235 if (!tinfo->simple_ancestors)
236 traverse_offset_bases(valptr, tinfo, self, register_instance_impl);
237 }
238
deregister_instance(instance * self,void * valptr,const type_info * tinfo)239 inline bool deregister_instance(instance *self, void *valptr, const type_info *tinfo) {
240 bool ret = deregister_instance_impl(valptr, self);
241 if (!tinfo->simple_ancestors)
242 traverse_offset_bases(valptr, tinfo, self, deregister_instance_impl);
243 return ret;
244 }
245
246 /// Instance creation function for all pybind11 types. It allocates the internal instance layout for
247 /// holding C++ objects and holders. Allocation is done lazily (the first time the instance is cast
248 /// to a reference or pointer), and initialization is done by an `__init__` function.
make_new_instance(PyTypeObject * type)249 inline PyObject *make_new_instance(PyTypeObject *type) {
250 #if defined(PYPY_VERSION)
251 // PyPy gets tp_basicsize wrong (issue 2482) under multiple inheritance when the first inherited
252 // object is a a plain Python type (i.e. not derived from an extension type). Fix it.
253 ssize_t instance_size = static_cast<ssize_t>(sizeof(instance));
254 if (type->tp_basicsize < instance_size) {
255 type->tp_basicsize = instance_size;
256 }
257 #endif
258 PyObject *self = type->tp_alloc(type, 0);
259 auto inst = reinterpret_cast<instance *>(self);
260 // Allocate the value/holder internals:
261 inst->allocate_layout();
262
263 inst->owned = true;
264
265 return self;
266 }
267
268 /// Instance creation function for all pybind11 types. It only allocates space for the
269 /// C++ object, but doesn't call the constructor -- an `__init__` function must do that.
pybind11_object_new(PyTypeObject * type,PyObject *,PyObject *)270 extern "C" inline PyObject *pybind11_object_new(PyTypeObject *type, PyObject *, PyObject *) {
271 return make_new_instance(type);
272 }
273
274 /// An `__init__` function constructs the C++ object. Users should provide at least one
275 /// of these using `py::init` or directly with `.def(__init__, ...)`. Otherwise, the
276 /// following default function will be used which simply throws an exception.
pybind11_object_init(PyObject * self,PyObject *,PyObject *)277 extern "C" inline int pybind11_object_init(PyObject *self, PyObject *, PyObject *) {
278 PyTypeObject *type = Py_TYPE(self);
279 std::string msg;
280 #if defined(PYPY_VERSION)
281 msg += handle((PyObject *) type).attr("__module__").cast<std::string>() + ".";
282 #endif
283 msg += type->tp_name;
284 msg += ": No constructor defined!";
285 PyErr_SetString(PyExc_TypeError, msg.c_str());
286 return -1;
287 }
288
add_patient(PyObject * nurse,PyObject * patient)289 inline void add_patient(PyObject *nurse, PyObject *patient) {
290 auto &internals = get_internals();
291 auto instance = reinterpret_cast<detail::instance *>(nurse);
292 auto ¤t_patients = internals.patients[nurse];
293 instance->has_patients = true;
294 for (auto &p : current_patients)
295 if (p == patient)
296 return;
297 Py_INCREF(patient);
298 current_patients.push_back(patient);
299 }
300
clear_patients(PyObject * self)301 inline void clear_patients(PyObject *self) {
302 auto instance = reinterpret_cast<detail::instance *>(self);
303 auto &internals = get_internals();
304 auto pos = internals.patients.find(self);
305 assert(pos != internals.patients.end());
306 // Clearing the patients can cause more Python code to run, which
307 // can invalidate the iterator. Extract the vector of patients
308 // from the unordered_map first.
309 auto patients = std::move(pos->second);
310 internals.patients.erase(pos);
311 instance->has_patients = false;
312 for (PyObject *&patient : patients)
313 Py_CLEAR(patient);
314 }
315
316 /// Clears all internal data from the instance and removes it from registered instances in
317 /// preparation for deallocation.
clear_instance(PyObject * self)318 inline void clear_instance(PyObject *self) {
319 auto instance = reinterpret_cast<detail::instance *>(self);
320
321 // Deallocate any values/holders, if present:
322 for (auto &v_h : values_and_holders(instance)) {
323 if (v_h) {
324
325 // We have to deregister before we call dealloc because, for virtual MI types, we still
326 // need to be able to get the parent pointers.
327 if (v_h.instance_registered() && !deregister_instance(instance, v_h.value_ptr(), v_h.type))
328 pybind11_fail("pybind11_object_dealloc(): Tried to deallocate unregistered instance!");
329
330 if (instance->owned || v_h.holder_constructed())
331 v_h.type->dealloc(v_h);
332 }
333 }
334 // Deallocate the value/holder layout internals:
335 instance->deallocate_layout();
336
337 if (instance->weakrefs)
338 PyObject_ClearWeakRefs(self);
339
340 PyObject **dict_ptr = _PyObject_GetDictPtr(self);
341 if (dict_ptr)
342 Py_CLEAR(*dict_ptr);
343
344 if (instance->has_patients)
345 clear_patients(self);
346 }
347
348 /// Instance destructor function for all pybind11 types. It calls `type_info.dealloc`
349 /// to destroy the C++ object itself, while the rest is Python bookkeeping.
pybind11_object_dealloc(PyObject * self)350 extern "C" inline void pybind11_object_dealloc(PyObject *self) {
351 clear_instance(self);
352
353 auto type = Py_TYPE(self);
354 type->tp_free(self);
355
356 // `type->tp_dealloc != pybind11_object_dealloc` means that we're being called
357 // as part of a derived type's dealloc, in which case we're not allowed to decref
358 // the type here. For cross-module compatibility, we shouldn't compare directly
359 // with `pybind11_object_dealloc`, but with the common one stashed in internals.
360 auto pybind11_object_type = (PyTypeObject *) get_internals().instance_base;
361 if (type->tp_dealloc == pybind11_object_type->tp_dealloc)
362 Py_DECREF(type);
363 }
364
365 /** Create the type which can be used as a common base for all classes. This is
366 needed in order to satisfy Python's requirements for multiple inheritance.
367 Return value: New reference. */
make_object_base_type(PyTypeObject * metaclass)368 inline PyObject *make_object_base_type(PyTypeObject *metaclass) {
369 constexpr auto *name = "pybind11_object";
370 auto name_obj = reinterpret_steal<object>(PYBIND11_FROM_STRING(name));
371
372 /* Danger zone: from now (and until PyType_Ready), make sure to
373 issue no Python C API calls which could potentially invoke the
374 garbage collector (the GC will call type_traverse(), which will in
375 turn find the newly constructed type in an invalid state) */
376 auto heap_type = (PyHeapTypeObject *) metaclass->tp_alloc(metaclass, 0);
377 if (!heap_type)
378 pybind11_fail("make_object_base_type(): error allocating type!");
379
380 heap_type->ht_name = name_obj.inc_ref().ptr();
381 #ifdef PYBIND11_BUILTIN_QUALNAME
382 heap_type->ht_qualname = name_obj.inc_ref().ptr();
383 #endif
384
385 auto type = &heap_type->ht_type;
386 type->tp_name = name;
387 type->tp_base = type_incref(&PyBaseObject_Type);
388 type->tp_basicsize = static_cast<ssize_t>(sizeof(instance));
389 type->tp_flags = Py_TPFLAGS_DEFAULT | Py_TPFLAGS_BASETYPE | Py_TPFLAGS_HEAPTYPE;
390
391 type->tp_new = pybind11_object_new;
392 type->tp_init = pybind11_object_init;
393 type->tp_dealloc = pybind11_object_dealloc;
394
395 /* Support weak references (needed for the keep_alive feature) */
396 type->tp_weaklistoffset = offsetof(instance, weakrefs);
397
398 if (PyType_Ready(type) < 0)
399 pybind11_fail("PyType_Ready failed in make_object_base_type():" + error_string());
400
401 setattr((PyObject *) type, "__module__", str("pybind11_builtins"));
402 PYBIND11_SET_OLDPY_QUALNAME(type, name_obj);
403
404 assert(!PyType_HasFeature(type, Py_TPFLAGS_HAVE_GC));
405 return (PyObject *) heap_type;
406 }
407
408 /// dynamic_attr: Support for `d = instance.__dict__`.
pybind11_get_dict(PyObject * self,void *)409 extern "C" inline PyObject *pybind11_get_dict(PyObject *self, void *) {
410 PyObject *&dict = *_PyObject_GetDictPtr(self);
411 if (!dict)
412 dict = PyDict_New();
413 Py_XINCREF(dict);
414 return dict;
415 }
416
417 /// dynamic_attr: Support for `instance.__dict__ = dict()`.
pybind11_set_dict(PyObject * self,PyObject * new_dict,void *)418 extern "C" inline int pybind11_set_dict(PyObject *self, PyObject *new_dict, void *) {
419 if (!PyDict_Check(new_dict)) {
420 PyErr_Format(PyExc_TypeError, "__dict__ must be set to a dictionary, not a '%.200s'",
421 Py_TYPE(new_dict)->tp_name);
422 return -1;
423 }
424 PyObject *&dict = *_PyObject_GetDictPtr(self);
425 Py_INCREF(new_dict);
426 Py_CLEAR(dict);
427 dict = new_dict;
428 return 0;
429 }
430
431 /// dynamic_attr: Allow the garbage collector to traverse the internal instance `__dict__`.
pybind11_traverse(PyObject * self,visitproc visit,void * arg)432 extern "C" inline int pybind11_traverse(PyObject *self, visitproc visit, void *arg) {
433 PyObject *&dict = *_PyObject_GetDictPtr(self);
434 Py_VISIT(dict);
435 return 0;
436 }
437
438 /// dynamic_attr: Allow the GC to clear the dictionary.
pybind11_clear(PyObject * self)439 extern "C" inline int pybind11_clear(PyObject *self) {
440 PyObject *&dict = *_PyObject_GetDictPtr(self);
441 Py_CLEAR(dict);
442 return 0;
443 }
444
445 /// Give instances of this type a `__dict__` and opt into garbage collection.
enable_dynamic_attributes(PyHeapTypeObject * heap_type)446 inline void enable_dynamic_attributes(PyHeapTypeObject *heap_type) {
447 auto type = &heap_type->ht_type;
448 #if defined(PYPY_VERSION)
449 pybind11_fail(std::string(type->tp_name) + ": dynamic attributes are "
450 "currently not supported in "
451 "conjunction with PyPy!");
452 #endif
453 type->tp_flags |= Py_TPFLAGS_HAVE_GC;
454 type->tp_dictoffset = type->tp_basicsize; // place dict at the end
455 type->tp_basicsize += (ssize_t)sizeof(PyObject *); // and allocate enough space for it
456 type->tp_traverse = pybind11_traverse;
457 type->tp_clear = pybind11_clear;
458
459 static PyGetSetDef getset[] = {
460 {const_cast<char*>("__dict__"), pybind11_get_dict, pybind11_set_dict, nullptr, nullptr},
461 {nullptr, nullptr, nullptr, nullptr, nullptr}
462 };
463 type->tp_getset = getset;
464 }
465
466 /// buffer_protocol: Fill in the view as specified by flags.
pybind11_getbuffer(PyObject * obj,Py_buffer * view,int flags)467 extern "C" inline int pybind11_getbuffer(PyObject *obj, Py_buffer *view, int flags) {
468 // Look for a `get_buffer` implementation in this type's info or any bases (following MRO).
469 type_info *tinfo = nullptr;
470 for (auto type : reinterpret_borrow<tuple>(Py_TYPE(obj)->tp_mro)) {
471 tinfo = get_type_info((PyTypeObject *) type.ptr());
472 if (tinfo && tinfo->get_buffer)
473 break;
474 }
475 if (view == nullptr || obj == nullptr || !tinfo || !tinfo->get_buffer) {
476 if (view)
477 view->obj = nullptr;
478 PyErr_SetString(PyExc_BufferError, "pybind11_getbuffer(): Internal error");
479 return -1;
480 }
481 std::memset(view, 0, sizeof(Py_buffer));
482 buffer_info *info = tinfo->get_buffer(obj, tinfo->get_buffer_data);
483 view->obj = obj;
484 view->ndim = 1;
485 view->internal = info;
486 view->buf = info->ptr;
487 view->itemsize = info->itemsize;
488 view->len = view->itemsize;
489 for (auto s : info->shape)
490 view->len *= s;
491 if ((flags & PyBUF_FORMAT) == PyBUF_FORMAT)
492 view->format = const_cast<char *>(info->format.c_str());
493 if ((flags & PyBUF_STRIDES) == PyBUF_STRIDES) {
494 view->ndim = (int) info->ndim;
495 view->strides = &info->strides[0];
496 view->shape = &info->shape[0];
497 }
498 Py_INCREF(view->obj);
499 return 0;
500 }
501
502 /// buffer_protocol: Release the resources of the buffer.
pybind11_releasebuffer(PyObject *,Py_buffer * view)503 extern "C" inline void pybind11_releasebuffer(PyObject *, Py_buffer *view) {
504 delete (buffer_info *) view->internal;
505 }
506
507 /// Give this type a buffer interface.
enable_buffer_protocol(PyHeapTypeObject * heap_type)508 inline void enable_buffer_protocol(PyHeapTypeObject *heap_type) {
509 heap_type->ht_type.tp_as_buffer = &heap_type->as_buffer;
510 #if PY_MAJOR_VERSION < 3
511 heap_type->ht_type.tp_flags |= Py_TPFLAGS_HAVE_NEWBUFFER;
512 #endif
513
514 heap_type->as_buffer.bf_getbuffer = pybind11_getbuffer;
515 heap_type->as_buffer.bf_releasebuffer = pybind11_releasebuffer;
516 }
517
518 /** Create a brand new Python type according to the `type_record` specification.
519 Return value: New reference. */
make_new_python_type(const type_record & rec)520 inline PyObject* make_new_python_type(const type_record &rec) {
521 auto name = reinterpret_steal<object>(PYBIND11_FROM_STRING(rec.name));
522
523 auto qualname = name;
524 if (rec.scope && !PyModule_Check(rec.scope.ptr()) && hasattr(rec.scope, "__qualname__")) {
525 #if PY_MAJOR_VERSION >= 3
526 qualname = reinterpret_steal<object>(
527 PyUnicode_FromFormat("%U.%U", rec.scope.attr("__qualname__").ptr(), name.ptr()));
528 #else
529 qualname = str(rec.scope.attr("__qualname__").cast<std::string>() + "." + rec.name);
530 #endif
531 }
532
533 object module;
534 if (rec.scope) {
535 if (hasattr(rec.scope, "__module__"))
536 module = rec.scope.attr("__module__");
537 else if (hasattr(rec.scope, "__name__"))
538 module = rec.scope.attr("__name__");
539 }
540
541 auto full_name = c_str(
542 #if !defined(PYPY_VERSION)
543 module ? str(module).cast<std::string>() + "." + rec.name :
544 #endif
545 rec.name);
546
547 char *tp_doc = nullptr;
548 if (rec.doc && options::show_user_defined_docstrings()) {
549 /* Allocate memory for docstring (using PyObject_MALLOC, since
550 Python will free this later on) */
551 size_t size = strlen(rec.doc) + 1;
552 tp_doc = (char *) PyObject_MALLOC(size);
553 memcpy((void *) tp_doc, rec.doc, size);
554 }
555
556 auto &internals = get_internals();
557 auto bases = tuple(rec.bases);
558 auto base = (bases.size() == 0) ? internals.instance_base
559 : bases[0].ptr();
560
561 /* Danger zone: from now (and until PyType_Ready), make sure to
562 issue no Python C API calls which could potentially invoke the
563 garbage collector (the GC will call type_traverse(), which will in
564 turn find the newly constructed type in an invalid state) */
565 auto metaclass = rec.metaclass.ptr() ? (PyTypeObject *) rec.metaclass.ptr()
566 : internals.default_metaclass;
567
568 auto heap_type = (PyHeapTypeObject *) metaclass->tp_alloc(metaclass, 0);
569 if (!heap_type)
570 pybind11_fail(std::string(rec.name) + ": Unable to create type object!");
571
572 heap_type->ht_name = name.release().ptr();
573 #ifdef PYBIND11_BUILTIN_QUALNAME
574 heap_type->ht_qualname = qualname.inc_ref().ptr();
575 #endif
576
577 auto type = &heap_type->ht_type;
578 type->tp_name = full_name;
579 type->tp_doc = tp_doc;
580 type->tp_base = type_incref((PyTypeObject *)base);
581 type->tp_basicsize = static_cast<ssize_t>(sizeof(instance));
582 if (bases.size() > 0)
583 type->tp_bases = bases.release().ptr();
584
585 /* Don't inherit base __init__ */
586 type->tp_init = pybind11_object_init;
587
588 /* Supported protocols */
589 type->tp_as_number = &heap_type->as_number;
590 type->tp_as_sequence = &heap_type->as_sequence;
591 type->tp_as_mapping = &heap_type->as_mapping;
592
593 /* Flags */
594 type->tp_flags |= Py_TPFLAGS_DEFAULT | Py_TPFLAGS_BASETYPE | Py_TPFLAGS_HEAPTYPE;
595 #if PY_MAJOR_VERSION < 3
596 type->tp_flags |= Py_TPFLAGS_CHECKTYPES;
597 #endif
598
599 if (rec.dynamic_attr)
600 enable_dynamic_attributes(heap_type);
601
602 if (rec.buffer_protocol)
603 enable_buffer_protocol(heap_type);
604
605 if (PyType_Ready(type) < 0)
606 pybind11_fail(std::string(rec.name) + ": PyType_Ready failed (" + error_string() + ")!");
607
608 assert(rec.dynamic_attr ? PyType_HasFeature(type, Py_TPFLAGS_HAVE_GC)
609 : !PyType_HasFeature(type, Py_TPFLAGS_HAVE_GC));
610
611 /* Register type with the parent scope */
612 if (rec.scope)
613 setattr(rec.scope, rec.name, (PyObject *) type);
614 else
615 Py_INCREF(type); // Keep it alive forever (reference leak)
616
617 if (module) // Needed by pydoc
618 setattr((PyObject *) type, "__module__", module);
619
620 PYBIND11_SET_OLDPY_QUALNAME(type, qualname);
621
622 return (PyObject *) type;
623 }
624
625 NAMESPACE_END(detail)
626 NAMESPACE_END(PYBIND11_NAMESPACE)
627