1 /*
2 pybind11/detail/internals.h: Internal data structure and related functions
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 "../pytypes.h"
13
14 NAMESPACE_BEGIN(PYBIND11_NAMESPACE)
15 NAMESPACE_BEGIN(detail)
16 // Forward declarations
17 inline PyTypeObject *make_static_property_type();
18 inline PyTypeObject *make_default_metaclass();
19 inline PyObject *make_object_base_type(PyTypeObject *metaclass);
20
21 // The old Python Thread Local Storage (TLS) API is deprecated in Python 3.7 in favor of the new
22 // Thread Specific Storage (TSS) API.
23 #if PY_VERSION_HEX >= 0x03070000
24 # define PYBIND11_TLS_KEY_INIT(var) Py_tss_t *var = nullptr
25 # define PYBIND11_TLS_GET_VALUE(key) PyThread_tss_get((key))
26 # define PYBIND11_TLS_REPLACE_VALUE(key, value) PyThread_tss_set((key), (value))
27 # define PYBIND11_TLS_DELETE_VALUE(key) PyThread_tss_set((key), nullptr)
28 # define PYBIND11_TLS_FREE(key) PyThread_tss_free(key)
29 #else
30 // Usually an int but a long on Cygwin64 with Python 3.x
31 # define PYBIND11_TLS_KEY_INIT(var) decltype(PyThread_create_key()) var = 0
32 # define PYBIND11_TLS_GET_VALUE(key) PyThread_get_key_value((key))
33 # if PY_MAJOR_VERSION < 3
34 # define PYBIND11_TLS_DELETE_VALUE(key) \
35 PyThread_delete_key_value(key)
36 # define PYBIND11_TLS_REPLACE_VALUE(key, value) \
37 do { \
38 PyThread_delete_key_value((key)); \
39 PyThread_set_key_value((key), (value)); \
40 } while (false)
41 # else
42 # define PYBIND11_TLS_DELETE_VALUE(key) \
43 PyThread_set_key_value((key), nullptr)
44 # define PYBIND11_TLS_REPLACE_VALUE(key, value) \
45 PyThread_set_key_value((key), (value))
46 # endif
47 # define PYBIND11_TLS_FREE(key) (void)key
48 #endif
49
50 // Python loads modules by default with dlopen with the RTLD_LOCAL flag; under libc++ and possibly
51 // other STLs, this means `typeid(A)` from one module won't equal `typeid(A)` from another module
52 // even when `A` is the same, non-hidden-visibility type (e.g. from a common include). Under
53 // libstdc++, this doesn't happen: equality and the type_index hash are based on the type name,
54 // which works. If not under a known-good stl, provide our own name-based hash and equality
55 // functions that use the type name.
56 #if defined(__GLIBCXX__)
same_type(const std::type_info & lhs,const std::type_info & rhs)57 inline bool same_type(const std::type_info &lhs, const std::type_info &rhs) { return lhs == rhs; }
58 using type_hash = std::hash<std::type_index>;
59 using type_equal_to = std::equal_to<std::type_index>;
60 #else
same_type(const std::type_info & lhs,const std::type_info & rhs)61 inline bool same_type(const std::type_info &lhs, const std::type_info &rhs) {
62 return lhs.name() == rhs.name() || std::strcmp(lhs.name(), rhs.name()) == 0;
63 }
64
65 struct type_hash {
operatortype_hash66 size_t operator()(const std::type_index &t) const {
67 size_t hash = 5381;
68 const char *ptr = t.name();
69 while (auto c = static_cast<unsigned char>(*ptr++))
70 hash = (hash * 33) ^ c;
71 return hash;
72 }
73 };
74
75 struct type_equal_to {
operatortype_equal_to76 bool operator()(const std::type_index &lhs, const std::type_index &rhs) const {
77 return lhs.name() == rhs.name() || std::strcmp(lhs.name(), rhs.name()) == 0;
78 }
79 };
80 #endif
81
82 template <typename value_type>
83 using type_map = std::unordered_map<std::type_index, value_type, type_hash, type_equal_to>;
84
85 struct overload_hash {
operatoroverload_hash86 inline size_t operator()(const std::pair<const PyObject *, const char *>& v) const {
87 size_t value = std::hash<const void *>()(v.first);
88 value ^= std::hash<const void *>()(v.second) + 0x9e3779b9 + (value<<6) + (value>>2);
89 return value;
90 }
91 };
92
93 /// Internal data structure used to track registered instances and types.
94 /// Whenever binary incompatible changes are made to this structure,
95 /// `PYBIND11_INTERNALS_VERSION` must be incremented.
96 struct internals {
97 type_map<type_info *> registered_types_cpp; // std::type_index -> pybind11's type information
98 std::unordered_map<PyTypeObject *, std::vector<type_info *>> registered_types_py; // PyTypeObject* -> base type_info(s)
99 std::unordered_multimap<const void *, instance*> registered_instances; // void * -> instance*
100 std::unordered_set<std::pair<const PyObject *, const char *>, overload_hash> inactive_overload_cache;
101 type_map<std::vector<bool (*)(PyObject *, void *&)>> direct_conversions;
102 std::unordered_map<const PyObject *, std::vector<PyObject *>> patients;
103 std::forward_list<void (*) (std::exception_ptr)> registered_exception_translators;
104 std::unordered_map<std::string, void *> shared_data; // Custom data to be shared across extensions
105 std::vector<PyObject *> loader_patient_stack; // Used by `loader_life_support`
106 std::forward_list<std::string> static_strings; // Stores the std::strings backing detail::c_str()
107 PyTypeObject *static_property_type;
108 PyTypeObject *default_metaclass;
109 PyObject *instance_base;
110 #if defined(WITH_THREAD)
111 PYBIND11_TLS_KEY_INIT(tstate);
112 PyInterpreterState *istate = nullptr;
~internalsinternals113 ~internals() {
114 // This destructor is called *after* Py_Finalize() in finalize_interpreter().
115 // That *SHOULD BE* fine. The following details what happens whe PyThread_tss_free is called.
116 // PYBIND11_TLS_FREE is PyThread_tss_free on python 3.7+. On older python, it does nothing.
117 // PyThread_tss_free calls PyThread_tss_delete and PyMem_RawFree.
118 // PyThread_tss_delete just calls TlsFree (on Windows) or pthread_key_delete (on *NIX). Neither
119 // of those have anything to do with CPython internals.
120 // PyMem_RawFree *requires* that the `tstate` be allocated with the CPython allocator.
121 PYBIND11_TLS_FREE(tstate);
122 }
123 #endif
124 };
125
126 /// Additional type information which does not fit into the PyTypeObject.
127 /// Changes to this struct also require bumping `PYBIND11_INTERNALS_VERSION`.
128 struct type_info {
129 PyTypeObject *type;
130 const std::type_info *cpptype;
131 size_t type_size, type_align, holder_size_in_ptrs;
132 void *(*operator_new)(size_t);
133 void (*init_instance)(instance *, const void *);
134 void (*dealloc)(value_and_holder &v_h);
135 std::vector<PyObject *(*)(PyObject *, PyTypeObject *)> implicit_conversions;
136 std::vector<std::pair<const std::type_info *, void *(*)(void *)>> implicit_casts;
137 std::vector<bool (*)(PyObject *, void *&)> *direct_conversions;
138 buffer_info *(*get_buffer)(PyObject *, void *) = nullptr;
139 void *get_buffer_data = nullptr;
140 void *(*module_local_load)(PyObject *, const type_info *) = nullptr;
141 /* A simple type never occurs as a (direct or indirect) parent
142 * of a class that makes use of multiple inheritance */
143 bool simple_type : 1;
144 /* True if there is no multiple inheritance in this type's inheritance tree */
145 bool simple_ancestors : 1;
146 /* for base vs derived holder_type checks */
147 bool default_holder : 1;
148 /* true if this is a type registered with py::module_local */
149 bool module_local : 1;
150 };
151
152 /// Tracks the `internals` and `type_info` ABI version independent of the main library version
153 #define PYBIND11_INTERNALS_VERSION 4
154
155 /// On MSVC, debug and release builds are not ABI-compatible!
156 #if defined(_MSC_VER) && defined(_DEBUG)
157 # define PYBIND11_BUILD_TYPE "_debug"
158 #else
159 # define PYBIND11_BUILD_TYPE ""
160 #endif
161
162 /// Let's assume that different compilers are ABI-incompatible.
163 #if defined(_MSC_VER)
164 # define PYBIND11_COMPILER_TYPE "_msvc"
165 #elif defined(__INTEL_COMPILER)
166 # define PYBIND11_COMPILER_TYPE "_icc"
167 #elif defined(__clang__)
168 # define PYBIND11_COMPILER_TYPE "_clang"
169 #elif defined(__PGI)
170 # define PYBIND11_COMPILER_TYPE "_pgi"
171 #elif defined(__MINGW32__)
172 # define PYBIND11_COMPILER_TYPE "_mingw"
173 #elif defined(__CYGWIN__)
174 # define PYBIND11_COMPILER_TYPE "_gcc_cygwin"
175 #elif defined(__GNUC__)
176 # define PYBIND11_COMPILER_TYPE "_gcc"
177 #else
178 # define PYBIND11_COMPILER_TYPE "_unknown"
179 #endif
180
181 #if defined(_LIBCPP_VERSION)
182 # define PYBIND11_STDLIB "_libcpp"
183 #elif defined(__GLIBCXX__) || defined(__GLIBCPP__)
184 # define PYBIND11_STDLIB "_libstdcpp"
185 #else
186 # define PYBIND11_STDLIB ""
187 #endif
188
189 /// On Linux/OSX, changes in __GXX_ABI_VERSION__ indicate ABI incompatibility.
190 #if defined(__GXX_ABI_VERSION)
191 # define PYBIND11_BUILD_ABI "_cxxabi" PYBIND11_TOSTRING(__GXX_ABI_VERSION)
192 #else
193 # define PYBIND11_BUILD_ABI ""
194 #endif
195
196 #if defined(WITH_THREAD)
197 # define PYBIND11_INTERNALS_KIND ""
198 #else
199 # define PYBIND11_INTERNALS_KIND "_without_thread"
200 #endif
201
202 #define PYBIND11_INTERNALS_ID "__pybind11_internals_v" \
203 PYBIND11_TOSTRING(PYBIND11_INTERNALS_VERSION) PYBIND11_INTERNALS_KIND PYBIND11_COMPILER_TYPE PYBIND11_STDLIB PYBIND11_BUILD_ABI PYBIND11_BUILD_TYPE "__"
204
205 #define PYBIND11_MODULE_LOCAL_ID "__pybind11_module_local_v" \
206 PYBIND11_TOSTRING(PYBIND11_INTERNALS_VERSION) PYBIND11_INTERNALS_KIND PYBIND11_COMPILER_TYPE PYBIND11_STDLIB PYBIND11_BUILD_ABI PYBIND11_BUILD_TYPE "__"
207
208 /// Each module locally stores a pointer to the `internals` data. The data
209 /// itself is shared among modules with the same `PYBIND11_INTERNALS_ID`.
get_internals_pp()210 inline internals **&get_internals_pp() {
211 static internals **internals_pp = nullptr;
212 return internals_pp;
213 }
214
translate_exception(std::exception_ptr p)215 inline void translate_exception(std::exception_ptr p) {
216 try {
217 if (p) std::rethrow_exception(p);
218 } catch (error_already_set &e) { e.restore(); return;
219 } catch (const builtin_exception &e) { e.set_error(); return;
220 } catch (const std::bad_alloc &e) { PyErr_SetString(PyExc_MemoryError, e.what()); return;
221 } catch (const std::domain_error &e) { PyErr_SetString(PyExc_ValueError, e.what()); return;
222 } catch (const std::invalid_argument &e) { PyErr_SetString(PyExc_ValueError, e.what()); return;
223 } catch (const std::length_error &e) { PyErr_SetString(PyExc_ValueError, e.what()); return;
224 } catch (const std::out_of_range &e) { PyErr_SetString(PyExc_IndexError, e.what()); return;
225 } catch (const std::range_error &e) { PyErr_SetString(PyExc_ValueError, e.what()); return;
226 } catch (const std::overflow_error &e) { PyErr_SetString(PyExc_OverflowError, e.what()); return;
227 } catch (const std::exception &e) { PyErr_SetString(PyExc_RuntimeError, e.what()); return;
228 } catch (...) {
229 PyErr_SetString(PyExc_RuntimeError, "Caught an unknown exception!");
230 return;
231 }
232 }
233
234 #if !defined(__GLIBCXX__)
translate_local_exception(std::exception_ptr p)235 inline void translate_local_exception(std::exception_ptr p) {
236 try {
237 if (p) std::rethrow_exception(p);
238 } catch (error_already_set &e) { e.restore(); return;
239 } catch (const builtin_exception &e) { e.set_error(); return;
240 }
241 }
242 #endif
243
244 /// Return a reference to the current `internals` data
get_internals()245 PYBIND11_NOINLINE inline internals &get_internals() {
246 auto **&internals_pp = get_internals_pp();
247 if (internals_pp && *internals_pp)
248 return **internals_pp;
249
250 // Ensure that the GIL is held since we will need to make Python calls.
251 // Cannot use py::gil_scoped_acquire here since that constructor calls get_internals.
252 struct gil_scoped_acquire_local {
253 gil_scoped_acquire_local() : state (PyGILState_Ensure()) {}
254 ~gil_scoped_acquire_local() { PyGILState_Release(state); }
255 const PyGILState_STATE state;
256 } gil;
257
258 constexpr auto *id = PYBIND11_INTERNALS_ID;
259 auto builtins = handle(PyEval_GetBuiltins());
260 if (builtins.contains(id) && isinstance<capsule>(builtins[id])) {
261 internals_pp = static_cast<internals **>(capsule(builtins[id]));
262
263 // We loaded builtins through python's builtins, which means that our `error_already_set`
264 // and `builtin_exception` may be different local classes than the ones set up in the
265 // initial exception translator, below, so add another for our local exception classes.
266 //
267 // libstdc++ doesn't require this (types there are identified only by name)
268 #if !defined(__GLIBCXX__)
269 (*internals_pp)->registered_exception_translators.push_front(&translate_local_exception);
270 #endif
271 } else {
272 if (!internals_pp) internals_pp = new internals*();
273 auto *&internals_ptr = *internals_pp;
274 internals_ptr = new internals();
275 #if defined(WITH_THREAD)
276 PyEval_InitThreads();
277 PyThreadState *tstate = PyThreadState_Get();
278 #if PY_VERSION_HEX >= 0x03070000
279 internals_ptr->tstate = PyThread_tss_alloc();
280 if (!internals_ptr->tstate || PyThread_tss_create(internals_ptr->tstate))
281 pybind11_fail("get_internals: could not successfully initialize the TSS key!");
282 PyThread_tss_set(internals_ptr->tstate, tstate);
283 #else
284 internals_ptr->tstate = PyThread_create_key();
285 if (internals_ptr->tstate == -1)
286 pybind11_fail("get_internals: could not successfully initialize the TLS key!");
287 PyThread_set_key_value(internals_ptr->tstate, tstate);
288 #endif
289 internals_ptr->istate = tstate->interp;
290 #endif
291 builtins[id] = capsule(internals_pp);
292 internals_ptr->registered_exception_translators.push_front(&translate_exception);
293 internals_ptr->static_property_type = make_static_property_type();
294 internals_ptr->default_metaclass = make_default_metaclass();
295 internals_ptr->instance_base = make_object_base_type(internals_ptr->default_metaclass);
296 }
297 return **internals_pp;
298 }
299
300 /// Works like `internals.registered_types_cpp`, but for module-local registered types:
registered_local_types_cpp()301 inline type_map<type_info *> ®istered_local_types_cpp() {
302 static type_map<type_info *> locals{};
303 return locals;
304 }
305
306 /// Constructs a std::string with the given arguments, stores it in `internals`, and returns its
307 /// `c_str()`. Such strings objects have a long storage duration -- the internal strings are only
308 /// cleared when the program exits or after interpreter shutdown (when embedding), and so are
309 /// suitable for c-style strings needed by Python internals (such as PyTypeObject's tp_name).
310 template <typename... Args>
c_str(Args &&...args)311 const char *c_str(Args &&...args) {
312 auto &strings = get_internals().static_strings;
313 strings.emplace_front(std::forward<Args>(args)...);
314 return strings.front().c_str();
315 }
316
NAMESPACE_END(detail)317 NAMESPACE_END(detail)
318
319 /// Returns a named pointer that is shared among all extension modules (using the same
320 /// pybind11 version) running in the current interpreter. Names starting with underscores
321 /// are reserved for internal usage. Returns `nullptr` if no matching entry was found.
322 inline PYBIND11_NOINLINE void *get_shared_data(const std::string &name) {
323 auto &internals = detail::get_internals();
324 auto it = internals.shared_data.find(name);
325 return it != internals.shared_data.end() ? it->second : nullptr;
326 }
327
328 /// Set the shared data that can be later recovered by `get_shared_data()`.
set_shared_data(const std::string & name,void * data)329 inline PYBIND11_NOINLINE void *set_shared_data(const std::string &name, void *data) {
330 detail::get_internals().shared_data[name] = data;
331 return data;
332 }
333
334 /// Returns a typed reference to a shared data entry (by using `get_shared_data()`) if
335 /// such entry exists. Otherwise, a new object of default-constructible type `T` is
336 /// added to the shared data under the given name and a reference to it is returned.
337 template<typename T>
get_or_create_shared_data(const std::string & name)338 T &get_or_create_shared_data(const std::string &name) {
339 auto &internals = detail::get_internals();
340 auto it = internals.shared_data.find(name);
341 T *ptr = (T *) (it != internals.shared_data.end() ? it->second : nullptr);
342 if (!ptr) {
343 ptr = new T();
344 internals.shared_data[name] = ptr;
345 }
346 return *ptr;
347 }
348
349 NAMESPACE_END(PYBIND11_NAMESPACE)
350