/* pybind11/detail/class.h: Python C API implementation details for py::class_ Copyright (c) 2017 Wenzel Jakob All rights reserved. Use of this source code is governed by a BSD-style license that can be found in the LICENSE file. */ #pragma once #include "../attr.h" NAMESPACE_BEGIN(PYBIND11_NAMESPACE) NAMESPACE_BEGIN(detail) #if PY_VERSION_HEX >= 0x03030000 # define PYBIND11_BUILTIN_QUALNAME # define PYBIND11_SET_OLDPY_QUALNAME(obj, nameobj) #else // In pre-3.3 Python, we still set __qualname__ so that we can produce reliable function type // signatures; in 3.3+ this macro expands to nothing: # define PYBIND11_SET_OLDPY_QUALNAME(obj, nameobj) setattr((PyObject *) obj, "__qualname__", nameobj) #endif inline PyTypeObject *type_incref(PyTypeObject *type) { Py_INCREF(type); return type; } #if !defined(PYPY_VERSION) /// `pybind11_static_property.__get__()`: Always pass the class instead of the instance. extern "C" inline PyObject *pybind11_static_get(PyObject *self, PyObject * /*ob*/, PyObject *cls) { return PyProperty_Type.tp_descr_get(self, cls, cls); } /// `pybind11_static_property.__set__()`: Just like the above `__get__()`. extern "C" inline int pybind11_static_set(PyObject *self, PyObject *obj, PyObject *value) { PyObject *cls = PyType_Check(obj) ? obj : (PyObject *) Py_TYPE(obj); return PyProperty_Type.tp_descr_set(self, cls, value); } /** A `static_property` is the same as a `property` but the `__get__()` and `__set__()` methods are modified to always use the object type instead of a concrete instance. Return value: New reference. */ inline PyTypeObject *make_static_property_type() { constexpr auto *name = "pybind11_static_property"; auto name_obj = reinterpret_steal(PYBIND11_FROM_STRING(name)); /* Danger zone: from now (and until PyType_Ready), make sure to issue no Python C API calls which could potentially invoke the garbage collector (the GC will call type_traverse(), which will in turn find the newly constructed type in an invalid state) */ auto heap_type = (PyHeapTypeObject *) PyType_Type.tp_alloc(&PyType_Type, 0); if (!heap_type) pybind11_fail("make_static_property_type(): error allocating type!"); heap_type->ht_name = name_obj.inc_ref().ptr(); #ifdef PYBIND11_BUILTIN_QUALNAME heap_type->ht_qualname = name_obj.inc_ref().ptr(); #endif auto type = &heap_type->ht_type; type->tp_name = name; type->tp_base = type_incref(&PyProperty_Type); type->tp_flags = Py_TPFLAGS_DEFAULT | Py_TPFLAGS_BASETYPE | Py_TPFLAGS_HEAPTYPE; type->tp_descr_get = pybind11_static_get; type->tp_descr_set = pybind11_static_set; if (PyType_Ready(type) < 0) pybind11_fail("make_static_property_type(): failure in PyType_Ready()!"); setattr((PyObject *) type, "__module__", str("pybind11_builtins")); PYBIND11_SET_OLDPY_QUALNAME(type, name_obj); return type; } #else // PYPY /** PyPy has some issues with the above C API, so we evaluate Python code instead. This function will only be called once so performance isn't really a concern. Return value: New reference. */ inline PyTypeObject *make_static_property_type() { auto d = dict(); PyObject *result = PyRun_String(R"(\ class pybind11_static_property(property): def __get__(self, obj, cls): return property.__get__(self, cls, cls) def __set__(self, obj, value): cls = obj if isinstance(obj, type) else type(obj) property.__set__(self, cls, value) )", Py_file_input, d.ptr(), d.ptr() ); if (result == nullptr) throw error_already_set(); Py_DECREF(result); return (PyTypeObject *) d["pybind11_static_property"].cast().release().ptr(); } #endif // PYPY /** Types with static properties need to handle `Type.static_prop = x` in a specific way. By default, Python replaces the `static_property` itself, but for wrapped C++ types we need to call `static_property.__set__()` in order to propagate the new value to the underlying C++ data structure. */ extern "C" inline int pybind11_meta_setattro(PyObject* obj, PyObject* name, PyObject* value) { // Use `_PyType_Lookup()` instead of `PyObject_GetAttr()` in order to get the raw // descriptor (`property`) instead of calling `tp_descr_get` (`property.__get__()`). PyObject *descr = _PyType_Lookup((PyTypeObject *) obj, name); // The following assignment combinations are possible: // 1. `Type.static_prop = value` --> descr_set: `Type.static_prop.__set__(value)` // 2. `Type.static_prop = other_static_prop` --> setattro: replace existing `static_prop` // 3. `Type.regular_attribute = value` --> setattro: regular attribute assignment const auto static_prop = (PyObject *) get_internals().static_property_type; const auto call_descr_set = descr && PyObject_IsInstance(descr, static_prop) && !PyObject_IsInstance(value, static_prop); if (call_descr_set) { // Call `static_property.__set__()` instead of replacing the `static_property`. #if !defined(PYPY_VERSION) return Py_TYPE(descr)->tp_descr_set(descr, obj, value); #else if (PyObject *result = PyObject_CallMethod(descr, "__set__", "OO", obj, value)) { Py_DECREF(result); return 0; } else { return -1; } #endif } else { // Replace existing attribute. return PyType_Type.tp_setattro(obj, name, value); } } #if PY_MAJOR_VERSION >= 3 /** * Python 3's PyInstanceMethod_Type hides itself via its tp_descr_get, which prevents aliasing * methods via cls.attr("m2") = cls.attr("m1"): instead the tp_descr_get returns a plain function, * when called on a class, or a PyMethod, when called on an instance. Override that behaviour here * to do a special case bypass for PyInstanceMethod_Types. */ extern "C" inline PyObject *pybind11_meta_getattro(PyObject *obj, PyObject *name) { PyObject *descr = _PyType_Lookup((PyTypeObject *) obj, name); if (descr && PyInstanceMethod_Check(descr)) { Py_INCREF(descr); return descr; } else { return PyType_Type.tp_getattro(obj, name); } } #endif /** This metaclass is assigned by default to all pybind11 types and is required in order for static properties to function correctly. Users may override this using `py::metaclass`. Return value: New reference. */ inline PyTypeObject* make_default_metaclass() { constexpr auto *name = "pybind11_type"; auto name_obj = reinterpret_steal(PYBIND11_FROM_STRING(name)); /* Danger zone: from now (and until PyType_Ready), make sure to issue no Python C API calls which could potentially invoke the garbage collector (the GC will call type_traverse(), which will in turn find the newly constructed type in an invalid state) */ auto heap_type = (PyHeapTypeObject *) PyType_Type.tp_alloc(&PyType_Type, 0); if (!heap_type) pybind11_fail("make_default_metaclass(): error allocating metaclass!"); heap_type->ht_name = name_obj.inc_ref().ptr(); #ifdef PYBIND11_BUILTIN_QUALNAME heap_type->ht_qualname = name_obj.inc_ref().ptr(); #endif auto type = &heap_type->ht_type; type->tp_name = name; type->tp_base = type_incref(&PyType_Type); type->tp_flags = Py_TPFLAGS_DEFAULT | Py_TPFLAGS_BASETYPE | Py_TPFLAGS_HEAPTYPE; type->tp_setattro = pybind11_meta_setattro; #if PY_MAJOR_VERSION >= 3 type->tp_getattro = pybind11_meta_getattro; #endif if (PyType_Ready(type) < 0) pybind11_fail("make_default_metaclass(): failure in PyType_Ready()!"); setattr((PyObject *) type, "__module__", str("pybind11_builtins")); PYBIND11_SET_OLDPY_QUALNAME(type, name_obj); return type; } /// For multiple inheritance types we need to recursively register/deregister base pointers for any /// base classes with pointers that are difference from the instance value pointer so that we can /// correctly recognize an offset base class pointer. This calls a function with any offset base ptrs. inline void traverse_offset_bases(void *valueptr, const detail::type_info *tinfo, instance *self, bool (*f)(void * /*parentptr*/, instance * /*self*/)) { for (handle h : reinterpret_borrow(tinfo->type->tp_bases)) { if (auto parent_tinfo = get_type_info((PyTypeObject *) h.ptr())) { for (auto &c : parent_tinfo->implicit_casts) { if (c.first == tinfo->cpptype) { auto *parentptr = c.second(valueptr); if (parentptr != valueptr) f(parentptr, self); traverse_offset_bases(parentptr, parent_tinfo, self, f); break; } } } } } inline bool register_instance_impl(void *ptr, instance *self) { get_internals().registered_instances.emplace(ptr, self); return true; // unused, but gives the same signature as the deregister func } inline bool deregister_instance_impl(void *ptr, instance *self) { auto ®istered_instances = get_internals().registered_instances; auto range = registered_instances.equal_range(ptr); for (auto it = range.first; it != range.second; ++it) { if (Py_TYPE(self) == Py_TYPE(it->second)) { registered_instances.erase(it); return true; } } return false; } inline void register_instance(instance *self, void *valptr, const type_info *tinfo) { register_instance_impl(valptr, self); if (!tinfo->simple_ancestors) traverse_offset_bases(valptr, tinfo, self, register_instance_impl); } inline bool deregister_instance(instance *self, void *valptr, const type_info *tinfo) { bool ret = deregister_instance_impl(valptr, self); if (!tinfo->simple_ancestors) traverse_offset_bases(valptr, tinfo, self, deregister_instance_impl); return ret; } /// Instance creation function for all pybind11 types. It allocates the internal instance layout for /// holding C++ objects and holders. Allocation is done lazily (the first time the instance is cast /// to a reference or pointer), and initialization is done by an `__init__` function. inline PyObject *make_new_instance(PyTypeObject *type) { #if defined(PYPY_VERSION) // PyPy gets tp_basicsize wrong (issue 2482) under multiple inheritance when the first inherited // object is a a plain Python type (i.e. not derived from an extension type). Fix it. ssize_t instance_size = static_cast(sizeof(instance)); if (type->tp_basicsize < instance_size) { type->tp_basicsize = instance_size; } #endif PyObject *self = type->tp_alloc(type, 0); auto inst = reinterpret_cast(self); // Allocate the value/holder internals: inst->allocate_layout(); inst->owned = true; return self; } /// Instance creation function for all pybind11 types. It only allocates space for the /// C++ object, but doesn't call the constructor -- an `__init__` function must do that. extern "C" inline PyObject *pybind11_object_new(PyTypeObject *type, PyObject *, PyObject *) { return make_new_instance(type); } /// An `__init__` function constructs the C++ object. Users should provide at least one /// of these using `py::init` or directly with `.def(__init__, ...)`. Otherwise, the /// following default function will be used which simply throws an exception. extern "C" inline int pybind11_object_init(PyObject *self, PyObject *, PyObject *) { PyTypeObject *type = Py_TYPE(self); std::string msg; #if defined(PYPY_VERSION) msg += handle((PyObject *) type).attr("__module__").cast() + "."; #endif msg += type->tp_name; msg += ": No constructor defined!"; PyErr_SetString(PyExc_TypeError, msg.c_str()); return -1; } inline void add_patient(PyObject *nurse, PyObject *patient) { auto &internals = get_internals(); auto instance = reinterpret_cast(nurse); auto ¤t_patients = internals.patients[nurse]; instance->has_patients = true; for (auto &p : current_patients) if (p == patient) return; Py_INCREF(patient); current_patients.push_back(patient); } inline void clear_patients(PyObject *self) { auto instance = reinterpret_cast(self); auto &internals = get_internals(); auto pos = internals.patients.find(self); assert(pos != internals.patients.end()); // Clearing the patients can cause more Python code to run, which // can invalidate the iterator. Extract the vector of patients // from the unordered_map first. auto patients = std::move(pos->second); internals.patients.erase(pos); instance->has_patients = false; for (PyObject *&patient : patients) Py_CLEAR(patient); } /// Clears all internal data from the instance and removes it from registered instances in /// preparation for deallocation. inline void clear_instance(PyObject *self) { auto instance = reinterpret_cast(self); // Deallocate any values/holders, if present: for (auto &v_h : values_and_holders(instance)) { if (v_h) { // We have to deregister before we call dealloc because, for virtual MI types, we still // need to be able to get the parent pointers. if (v_h.instance_registered() && !deregister_instance(instance, v_h.value_ptr(), v_h.type)) pybind11_fail("pybind11_object_dealloc(): Tried to deallocate unregistered instance!"); if (instance->owned || v_h.holder_constructed()) v_h.type->dealloc(v_h); } } // Deallocate the value/holder layout internals: instance->deallocate_layout(); if (instance->weakrefs) PyObject_ClearWeakRefs(self); PyObject **dict_ptr = _PyObject_GetDictPtr(self); if (dict_ptr) Py_CLEAR(*dict_ptr); if (instance->has_patients) clear_patients(self); } /// Instance destructor function for all pybind11 types. It calls `type_info.dealloc` /// to destroy the C++ object itself, while the rest is Python bookkeeping. extern "C" inline void pybind11_object_dealloc(PyObject *self) { clear_instance(self); auto type = Py_TYPE(self); type->tp_free(self); // `type->tp_dealloc != pybind11_object_dealloc` means that we're being called // as part of a derived type's dealloc, in which case we're not allowed to decref // the type here. For cross-module compatibility, we shouldn't compare directly // with `pybind11_object_dealloc`, but with the common one stashed in internals. auto pybind11_object_type = (PyTypeObject *) get_internals().instance_base; if (type->tp_dealloc == pybind11_object_type->tp_dealloc) Py_DECREF(type); } /** Create the type which can be used as a common base for all classes. This is needed in order to satisfy Python's requirements for multiple inheritance. Return value: New reference. */ inline PyObject *make_object_base_type(PyTypeObject *metaclass) { constexpr auto *name = "pybind11_object"; auto name_obj = reinterpret_steal(PYBIND11_FROM_STRING(name)); /* Danger zone: from now (and until PyType_Ready), make sure to issue no Python C API calls which could potentially invoke the garbage collector (the GC will call type_traverse(), which will in turn find the newly constructed type in an invalid state) */ auto heap_type = (PyHeapTypeObject *) metaclass->tp_alloc(metaclass, 0); if (!heap_type) pybind11_fail("make_object_base_type(): error allocating type!"); heap_type->ht_name = name_obj.inc_ref().ptr(); #ifdef PYBIND11_BUILTIN_QUALNAME heap_type->ht_qualname = name_obj.inc_ref().ptr(); #endif auto type = &heap_type->ht_type; type->tp_name = name; type->tp_base = type_incref(&PyBaseObject_Type); type->tp_basicsize = static_cast(sizeof(instance)); type->tp_flags = Py_TPFLAGS_DEFAULT | Py_TPFLAGS_BASETYPE | Py_TPFLAGS_HEAPTYPE; type->tp_new = pybind11_object_new; type->tp_init = pybind11_object_init; type->tp_dealloc = pybind11_object_dealloc; /* Support weak references (needed for the keep_alive feature) */ type->tp_weaklistoffset = offsetof(instance, weakrefs); if (PyType_Ready(type) < 0) pybind11_fail("PyType_Ready failed in make_object_base_type():" + error_string()); setattr((PyObject *) type, "__module__", str("pybind11_builtins")); PYBIND11_SET_OLDPY_QUALNAME(type, name_obj); assert(!PyType_HasFeature(type, Py_TPFLAGS_HAVE_GC)); return (PyObject *) heap_type; } /// dynamic_attr: Support for `d = instance.__dict__`. extern "C" inline PyObject *pybind11_get_dict(PyObject *self, void *) { PyObject *&dict = *_PyObject_GetDictPtr(self); if (!dict) dict = PyDict_New(); Py_XINCREF(dict); return dict; } /// dynamic_attr: Support for `instance.__dict__ = dict()`. extern "C" inline int pybind11_set_dict(PyObject *self, PyObject *new_dict, void *) { if (!PyDict_Check(new_dict)) { PyErr_Format(PyExc_TypeError, "__dict__ must be set to a dictionary, not a '%.200s'", Py_TYPE(new_dict)->tp_name); return -1; } PyObject *&dict = *_PyObject_GetDictPtr(self); Py_INCREF(new_dict); Py_CLEAR(dict); dict = new_dict; return 0; } /// dynamic_attr: Allow the garbage collector to traverse the internal instance `__dict__`. extern "C" inline int pybind11_traverse(PyObject *self, visitproc visit, void *arg) { PyObject *&dict = *_PyObject_GetDictPtr(self); Py_VISIT(dict); return 0; } /// dynamic_attr: Allow the GC to clear the dictionary. extern "C" inline int pybind11_clear(PyObject *self) { PyObject *&dict = *_PyObject_GetDictPtr(self); Py_CLEAR(dict); return 0; } /// Give instances of this type a `__dict__` and opt into garbage collection. inline void enable_dynamic_attributes(PyHeapTypeObject *heap_type) { auto type = &heap_type->ht_type; #if defined(PYPY_VERSION) pybind11_fail(std::string(type->tp_name) + ": dynamic attributes are " "currently not supported in " "conjunction with PyPy!"); #endif type->tp_flags |= Py_TPFLAGS_HAVE_GC; type->tp_dictoffset = type->tp_basicsize; // place dict at the end type->tp_basicsize += (ssize_t)sizeof(PyObject *); // and allocate enough space for it type->tp_traverse = pybind11_traverse; type->tp_clear = pybind11_clear; static PyGetSetDef getset[] = { {const_cast("__dict__"), pybind11_get_dict, pybind11_set_dict, nullptr, nullptr}, {nullptr, nullptr, nullptr, nullptr, nullptr} }; type->tp_getset = getset; } /// buffer_protocol: Fill in the view as specified by flags. extern "C" inline int pybind11_getbuffer(PyObject *obj, Py_buffer *view, int flags) { // Look for a `get_buffer` implementation in this type's info or any bases (following MRO). type_info *tinfo = nullptr; for (auto type : reinterpret_borrow(Py_TYPE(obj)->tp_mro)) { tinfo = get_type_info((PyTypeObject *) type.ptr()); if (tinfo && tinfo->get_buffer) break; } if (view == nullptr || obj == nullptr || !tinfo || !tinfo->get_buffer) { if (view) view->obj = nullptr; PyErr_SetString(PyExc_BufferError, "pybind11_getbuffer(): Internal error"); return -1; } std::memset(view, 0, sizeof(Py_buffer)); buffer_info *info = tinfo->get_buffer(obj, tinfo->get_buffer_data); view->obj = obj; view->ndim = 1; view->internal = info; view->buf = info->ptr; view->itemsize = info->itemsize; view->len = view->itemsize; for (auto s : info->shape) view->len *= s; if ((flags & PyBUF_FORMAT) == PyBUF_FORMAT) view->format = const_cast(info->format.c_str()); if ((flags & PyBUF_STRIDES) == PyBUF_STRIDES) { view->ndim = (int) info->ndim; view->strides = &info->strides[0]; view->shape = &info->shape[0]; } Py_INCREF(view->obj); return 0; } /// buffer_protocol: Release the resources of the buffer. extern "C" inline void pybind11_releasebuffer(PyObject *, Py_buffer *view) { delete (buffer_info *) view->internal; } /// Give this type a buffer interface. inline void enable_buffer_protocol(PyHeapTypeObject *heap_type) { heap_type->ht_type.tp_as_buffer = &heap_type->as_buffer; #if PY_MAJOR_VERSION < 3 heap_type->ht_type.tp_flags |= Py_TPFLAGS_HAVE_NEWBUFFER; #endif heap_type->as_buffer.bf_getbuffer = pybind11_getbuffer; heap_type->as_buffer.bf_releasebuffer = pybind11_releasebuffer; } /** Create a brand new Python type according to the `type_record` specification. Return value: New reference. */ inline PyObject* make_new_python_type(const type_record &rec) { auto name = reinterpret_steal(PYBIND11_FROM_STRING(rec.name)); auto qualname = name; if (rec.scope && !PyModule_Check(rec.scope.ptr()) && hasattr(rec.scope, "__qualname__")) { #if PY_MAJOR_VERSION >= 3 qualname = reinterpret_steal( PyUnicode_FromFormat("%U.%U", rec.scope.attr("__qualname__").ptr(), name.ptr())); #else qualname = str(rec.scope.attr("__qualname__").cast() + "." + rec.name); #endif } object module; if (rec.scope) { if (hasattr(rec.scope, "__module__")) module = rec.scope.attr("__module__"); else if (hasattr(rec.scope, "__name__")) module = rec.scope.attr("__name__"); } auto full_name = c_str( #if !defined(PYPY_VERSION) module ? str(module).cast() + "." + rec.name : #endif rec.name); char *tp_doc = nullptr; if (rec.doc && options::show_user_defined_docstrings()) { /* Allocate memory for docstring (using PyObject_MALLOC, since Python will free this later on) */ size_t size = strlen(rec.doc) + 1; tp_doc = (char *) PyObject_MALLOC(size); memcpy((void *) tp_doc, rec.doc, size); } auto &internals = get_internals(); auto bases = tuple(rec.bases); auto base = (bases.size() == 0) ? internals.instance_base : bases[0].ptr(); /* Danger zone: from now (and until PyType_Ready), make sure to issue no Python C API calls which could potentially invoke the garbage collector (the GC will call type_traverse(), which will in turn find the newly constructed type in an invalid state) */ auto metaclass = rec.metaclass.ptr() ? (PyTypeObject *) rec.metaclass.ptr() : internals.default_metaclass; auto heap_type = (PyHeapTypeObject *) metaclass->tp_alloc(metaclass, 0); if (!heap_type) pybind11_fail(std::string(rec.name) + ": Unable to create type object!"); heap_type->ht_name = name.release().ptr(); #ifdef PYBIND11_BUILTIN_QUALNAME heap_type->ht_qualname = qualname.inc_ref().ptr(); #endif auto type = &heap_type->ht_type; type->tp_name = full_name; type->tp_doc = tp_doc; type->tp_base = type_incref((PyTypeObject *)base); type->tp_basicsize = static_cast(sizeof(instance)); if (bases.size() > 0) type->tp_bases = bases.release().ptr(); /* Don't inherit base __init__ */ type->tp_init = pybind11_object_init; /* Supported protocols */ type->tp_as_number = &heap_type->as_number; type->tp_as_sequence = &heap_type->as_sequence; type->tp_as_mapping = &heap_type->as_mapping; /* Flags */ type->tp_flags |= Py_TPFLAGS_DEFAULT | Py_TPFLAGS_BASETYPE | Py_TPFLAGS_HEAPTYPE; #if PY_MAJOR_VERSION < 3 type->tp_flags |= Py_TPFLAGS_CHECKTYPES; #endif if (rec.dynamic_attr) enable_dynamic_attributes(heap_type); if (rec.buffer_protocol) enable_buffer_protocol(heap_type); if (PyType_Ready(type) < 0) pybind11_fail(std::string(rec.name) + ": PyType_Ready failed (" + error_string() + ")!"); assert(rec.dynamic_attr ? PyType_HasFeature(type, Py_TPFLAGS_HAVE_GC) : !PyType_HasFeature(type, Py_TPFLAGS_HAVE_GC)); /* Register type with the parent scope */ if (rec.scope) setattr(rec.scope, rec.name, (PyObject *) type); else Py_INCREF(type); // Keep it alive forever (reference leak) if (module) // Needed by pydoc setattr((PyObject *) type, "__module__", module); PYBIND11_SET_OLDPY_QUALNAME(type, qualname); return (PyObject *) type; } NAMESPACE_END(detail) NAMESPACE_END(PYBIND11_NAMESPACE)