diff options
Diffstat (limited to 'ext/pybind11/include/pybind11/class_support.h')
-rw-r--r-- | ext/pybind11/include/pybind11/class_support.h | 504 |
1 files changed, 504 insertions, 0 deletions
diff --git a/ext/pybind11/include/pybind11/class_support.h b/ext/pybind11/include/pybind11/class_support.h new file mode 100644 index 000000000..992703ff3 --- /dev/null +++ b/ext/pybind11/include/pybind11/class_support.h @@ -0,0 +1,504 @@ +/* + pybind11/class_support.h: Python C API implementation details for py::class_ + + Copyright (c) 2017 Wenzel Jakob <wenzel.jakob@epfl.ch> + + 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_BEGIN(detail) + +#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<object>(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(); +#if PY_MAJOR_VERSION >= 3 && PY_MINOR_VERSION >= 3 + heap_type->ht_qualname = name_obj.inc_ref().ptr(); +#endif + + auto type = &heap_type->ht_type; + type->tp_name = name; + type->tp_base = &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")); + + 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<object>().release().ptr(); +} + +#endif // PYPY + +/** Inheriting from multiple C++ types in Python is not supported -- set an error instead. + A Python definition (`class C(A, B): pass`) will call `tp_new` so we check for multiple + C++ bases here. On the other hand, C++ type definitions (`py::class_<C, A, B>(m, "C")`) + don't not use `tp_new` and will not trigger this error. */ +extern "C" inline PyObject *pybind11_meta_new(PyTypeObject *metaclass, PyObject *args, + PyObject *kwargs) { + PyObject *bases = PyTuple_GetItem(args, 1); // arguments: (name, bases, dict) + if (!bases) + return nullptr; + + auto &internals = get_internals(); + auto num_cpp_bases = 0; + for (auto base : reinterpret_borrow<tuple>(bases)) { + auto base_type = (PyTypeObject *) base.ptr(); + auto instance_size = static_cast<size_t>(base_type->tp_basicsize); + if (PyObject_IsSubclass(base.ptr(), internals.get_base(instance_size))) + ++num_cpp_bases; + } + + if (num_cpp_bases > 1) { + PyErr_SetString(PyExc_TypeError, "Can't inherit from multiple C++ classes in Python." + "Use py::class_ to define the class in C++ instead."); + return nullptr; + } else { + return PyType_Type.tp_new(metaclass, args, kwargs); + } +} + +/** 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); + + // Call `static_property.__set__()` instead of replacing the `static_property`. + if (descr && PyObject_IsInstance(descr, (PyObject *) get_internals().static_property_type)) { +#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 { + return PyType_Type.tp_setattro(obj, name, value); + } +} + +/** 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<object>(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(); +#if PY_MAJOR_VERSION >= 3 && PY_MINOR_VERSION >= 3 + heap_type->ht_qualname = name_obj.inc_ref().ptr(); +#endif + + auto type = &heap_type->ht_type; + type->tp_name = name; + type->tp_base = &PyType_Type; + type->tp_flags = Py_TPFLAGS_DEFAULT | Py_TPFLAGS_BASETYPE | Py_TPFLAGS_HEAPTYPE; + + type->tp_new = pybind11_meta_new; + type->tp_setattro = pybind11_meta_setattro; + + if (PyType_Ready(type) < 0) + pybind11_fail("make_default_metaclass(): failure in PyType_Ready()!"); + + setattr((PyObject *) type, "__module__", str("pybind11_builtins")); + + return type; +} + +/// 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 *) { + PyObject *self = type->tp_alloc(type, 0); + auto instance = (instance_essentials<void> *) self; + auto tinfo = get_type_info(type); + instance->value = tinfo->operator_new(tinfo->type_size); + instance->owned = true; + instance->holder_constructed = false; + get_internals().registered_instances.emplace(instance->value, self); + return self; +} + +/// 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<std::string>() + "."; +#endif + msg += type->tp_name; + msg += ": No constructor defined!"; + PyErr_SetString(PyExc_TypeError, msg.c_str()); + return -1; +} + +/// 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) { + auto instance = (instance_essentials<void> *) self; + if (instance->value) { + auto type = Py_TYPE(self); + get_type_info(type)->dealloc(self); + + auto ®istered_instances = get_internals().registered_instances; + auto range = registered_instances.equal_range(instance->value); + bool found = false; + for (auto it = range.first; it != range.second; ++it) { + if (type == Py_TYPE(it->second)) { + registered_instances.erase(it); + found = true; + break; + } + } + if (!found) + pybind11_fail("pybind11_object_dealloc(): Tried to deallocate unregistered instance!"); + + if (instance->weakrefs) + PyObject_ClearWeakRefs(self); + + PyObject **dict_ptr = _PyObject_GetDictPtr(self); + if (dict_ptr) + Py_CLEAR(*dict_ptr); + } + Py_TYPE(self)->tp_free(self); +} + +/** Create a type which can be used as a common base for all classes with the same + instance size, i.e. all classes with the same `sizeof(holder_type)`. This is + needed in order to satisfy Python's requirements for multiple inheritance. + Return value: New reference. */ +inline PyObject *make_object_base_type(size_t instance_size) { + auto name = "pybind11_object_" + std::to_string(instance_size); + auto name_obj = reinterpret_steal<object>(PYBIND11_FROM_STRING(name.c_str())); + + /* 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 = get_internals().default_metaclass; + 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(); +#if PY_MAJOR_VERSION >= 3 && PY_MINOR_VERSION >= 3 + heap_type->ht_qualname = name_obj.inc_ref().ptr(); +#endif + + auto type = &heap_type->ht_type; + type->tp_name = strdup(name.c_str()); + type->tp_base = &PyBaseObject_Type; + type->tp_basicsize = static_cast<ssize_t>(instance_size); + 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_essentials<void>, 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")); + + assert(!PyType_HasFeature(type, Py_TPFLAGS_HAVE_GC)); + return (PyObject *) heap_type; +} + +/** Return the appropriate base type for the given instance size. The results are cached + in `internals.bases` so that only a single base is ever created for any size value. + Return value: Borrowed reference. */ +inline PyObject *internals::get_base(size_t instance_size) { + auto it = bases.find(instance_size); + if (it != bases.end()) { + return it->second; + } else { + auto base = make_object_base_type(instance_size); + bases[instance_size] = base; + return base; + } +} + +/// 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 += sizeof(PyObject *); // and allocate enough space for it + type->tp_traverse = pybind11_traverse; + type->tp_clear = pybind11_clear; + + static PyGetSetDef getset[] = { + {const_cast<char*>("__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) { + auto tinfo = get_type_info(Py_TYPE(obj)); + if (view == nullptr || obj == nullptr || !tinfo || !tinfo->get_buffer) { + if (view) + view->obj = nullptr; + PyErr_SetString(PyExc_BufferError, "generic_type::getbuffer(): Internal error"); + return -1; + } + 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 = (ssize_t) info->itemsize; + view->len = view->itemsize; + for (auto s : info->shape) + view->len *= s; + if ((flags & PyBUF_FORMAT) == PyBUF_FORMAT) + view->format = const_cast<char *>(info->format.c_str()); + if ((flags & PyBUF_STRIDES) == PyBUF_STRIDES) { + view->ndim = (int) info->ndim; + view->strides = (ssize_t *) &info->strides[0]; + view->shape = (ssize_t *) &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<object>(PYBIND11_FROM_STRING(rec.name)); + +#if PY_MAJOR_VERSION >= 3 && PY_MINOR_VERSION >= 3 + auto ht_qualname = name; + if (rec.scope && hasattr(rec.scope, "__qualname__")) { + ht_qualname = reinterpret_steal<object>( + PyUnicode_FromFormat("%U.%U", rec.scope.attr("__qualname__").ptr(), name.ptr())); + } +#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__"); + } + +#if !defined(PYPY_VERSION) + const auto full_name = module ? str(module).cast<std::string>() + "." + rec.name + : std::string(rec.name); +#else + const auto full_name = std::string(rec.name); +#endif + + 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.get_base(rec.instance_size) + : 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(); +#if PY_MAJOR_VERSION >= 3 && PY_MINOR_VERSION >= 3 + heap_type->ht_qualname = ht_qualname.release().ptr(); +#endif + + auto type = &heap_type->ht_type; + type->tp_name = strdup(full_name.c_str()); + type->tp_doc = tp_doc; + type->tp_base = (PyTypeObject *) handle(base).inc_ref().ptr(); + type->tp_basicsize = static_cast<ssize_t>(rec.instance_size); + 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); + + if (module) // Needed by pydoc + setattr((PyObject *) type, "__module__", module); + + return (PyObject *) type; +} + +NAMESPACE_END(detail) +NAMESPACE_END(pybind11) |