1 /*
2 pybind11/detail/internals.h: Internal data structure and related functions
4 Copyright (c) 2017 Wenzel Jakob <wenzel.jakob@epfl.ch>
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 */
10 #pragma once
12 #include "../pytypes.h"
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);
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), (tstate))
27 # define PYBIND11_TLS_DELETE_VALUE(key) PyThread_tss_set((key), nullptr)
28 #else
29 // Usually an int but a long on Cygwin64 with Python 3.x
30 # define PYBIND11_TLS_KEY_INIT(var) decltype(PyThread_create_key()) var = 0
31 # define PYBIND11_TLS_GET_VALUE(key) PyThread_get_key_value((key))
32 # if PY_MAJOR_VERSION < 3
33 # define PYBIND11_TLS_DELETE_VALUE(key) \
34 PyThread_delete_key_value(key)
35 # define PYBIND11_TLS_REPLACE_VALUE(key, value) \
36 do { \
37 PyThread_delete_key_value((key)); \
38 PyThread_set_key_value((key), (value)); \
39 } while (false)
40 # else
41 # define PYBIND11_TLS_DELETE_VALUE(key) \
42 PyThread_set_key_value((key), nullptr)
43 # define PYBIND11_TLS_REPLACE_VALUE(key, value) \
44 PyThread_set_key_value((key), (value))
45 # endif
46 #endif
48 // Python loads modules by default with dlopen with the RTLD_LOCAL flag; under libc++ and possibly
49 // other STLs, this means `typeid(A)` from one module won't equal `typeid(A)` from another module
50 // even when `A` is the same, non-hidden-visibility type (e.g. from a common include). Under
51 // libstdc++, this doesn't happen: equality and the type_index hash are based on the type name,
52 // which works. If not under a known-good stl, provide our own name-based hash and equality
53 // functions that use the type name.
54 #if defined(__GLIBCXX__)
55 inline bool same_type(const std::type_info &lhs, const std::type_info &rhs) { return lhs == rhs; }
56 using type_hash = std::hash<std::type_index>;
57 using type_equal_to = std::equal_to<std::type_index>;
58 #else
59 inline bool same_type(const std::type_info &lhs, const std::type_info &rhs) {
60 return lhs.name() == rhs.name() || std::strcmp(lhs.name(), rhs.name()) == 0;
61 }
63 struct type_hash {
64 size_t operator()(const std::type_index &t) const {
65 size_t hash = 5381;
66 const char *ptr = t.name();
67 while (auto c = static_cast<unsigned char>(*ptr++))
68 hash = (hash * 33) ^ c;
69 return hash;
70 }
71 };
73 struct type_equal_to {
74 bool operator()(const std::type_index &lhs, const std::type_index &rhs) const {
75 return lhs.name() == rhs.name() || std::strcmp(lhs.name(), rhs.name()) == 0;
76 }
77 };
78 #endif
80 template <typename value_type>
81 using type_map = std::unordered_map<std::type_index, value_type, type_hash, type_equal_to>;
83 struct overload_hash {
84 inline size_t operator()(const std::pair<const PyObject *, const char *>& v) const {
85 size_t value = std::hash<const void *>()(v.first);
86 value ^= std::hash<const void *>()(v.second) + 0x9e3779b9 + (value<<6) + (value>>2);
87 return value;
88 }
89 };
91 /// Internal data structure used to track registered instances and types.
92 /// Whenever binary incompatible changes are made to this structure,
93 /// `PYBIND11_INTERNALS_VERSION` must be incremented.
94 struct internals {
95 type_map<type_info *> registered_types_cpp; // std::type_index -> pybind11's type information
96 std::unordered_map<PyTypeObject *, std::vector<type_info *>> registered_types_py; // PyTypeObject* -> base type_info(s)
97 std::unordered_multimap<const void *, instance*> registered_instances; // void * -> instance*
98 std::unordered_set<std::pair<const PyObject *, const char *>, overload_hash> inactive_overload_cache;
99 type_map<std::vector<bool (*)(PyObject *, void *&)>> direct_conversions;
100 std::unordered_map<const PyObject *, std::vector<PyObject *>> patients;
101 std::forward_list<void (*) (std::exception_ptr)> registered_exception_translators;
102 std::unordered_map<std::string, void *> shared_data; // Custom data to be shared across extensions
103 std::vector<PyObject *> loader_patient_stack; // Used by `loader_life_support`
104 std::forward_list<std::string> static_strings; // Stores the std::strings backing detail::c_str()
105 PyTypeObject *static_property_type;
106 PyTypeObject *default_metaclass;
107 PyObject *instance_base;
108 #if defined(WITH_THREAD)
109 PYBIND11_TLS_KEY_INIT(tstate);
110 PyInterpreterState *istate = nullptr;
111 #endif
112 };
114 /// Additional type information which does not fit into the PyTypeObject.
115 /// Changes to this struct also require bumping `PYBIND11_INTERNALS_VERSION`.
116 struct type_info {
117 PyTypeObject *type;
118 const std::type_info *cpptype;
119 size_t type_size, holder_size_in_ptrs;
120 void *(*operator_new)(size_t);
121 void (*init_instance)(instance *, const void *);
122 void (*dealloc)(value_and_holder &v_h);
123 std::vector<PyObject *(*)(PyObject *, PyTypeObject *)> implicit_conversions;
124 std::vector<std::pair<const std::type_info *, void *(*)(void *)>> implicit_casts;
125 std::vector<bool (*)(PyObject *, void *&)> *direct_conversions;
126 buffer_info *(*get_buffer)(PyObject *, void *) = nullptr;
127 void *get_buffer_data = nullptr;
128 void *(*module_local_load)(PyObject *, const type_info *) = nullptr;
129 /* A simple type never occurs as a (direct or indirect) parent
130 * of a class that makes use of multiple inheritance */
131 bool simple_type : 1;
132 /* True if there is no multiple inheritance in this type's inheritance tree */
133 bool simple_ancestors : 1;
134 /* for base vs derived holder_type checks */
135 bool default_holder : 1;
136 /* true if this is a type registered with py::module_local */
137 bool module_local : 1;
138 };
140 /// Tracks the `internals` and `type_info` ABI version independent of the main library version
141 #define PYBIND11_INTERNALS_VERSION 2
143 #if defined(WITH_THREAD)
144 # define PYBIND11_INTERNALS_KIND ""
145 #else
146 # define PYBIND11_INTERNALS_KIND "_without_thread"
147 #endif
149 #define PYBIND11_INTERNALS_ID "__pybind11_internals_v" \
150 PYBIND11_TOSTRING(PYBIND11_INTERNALS_VERSION) PYBIND11_INTERNALS_KIND "__"
152 #define PYBIND11_MODULE_LOCAL_ID "__pybind11_module_local_v" \
153 PYBIND11_TOSTRING(PYBIND11_INTERNALS_VERSION) PYBIND11_INTERNALS_KIND "__"
155 /// Each module locally stores a pointer to the `internals` data. The data
156 /// itself is shared among modules with the same `PYBIND11_INTERNALS_ID`.
157 inline internals **&get_internals_pp() {
158 static internals **internals_pp = nullptr;
159 return internals_pp;
160 }
162 /// Return a reference to the current `internals` data
163 PYBIND11_NOINLINE inline internals &get_internals() {
164 auto **&internals_pp = get_internals_pp();
165 if (internals_pp && *internals_pp)
166 return **internals_pp;
168 constexpr auto *id = PYBIND11_INTERNALS_ID;
169 auto builtins = handle(PyEval_GetBuiltins());
170 if (builtins.contains(id) && isinstance<capsule>(builtins[id])) {
171 internals_pp = static_cast<internals **>(capsule(builtins[id]));
173 // We loaded builtins through python's builtins, which means that our `error_already_set`
174 // and `builtin_exception` may be different local classes than the ones set up in the
175 // initial exception translator, below, so add another for our local exception classes.
176 //
177 // libstdc++ doesn't require this (types there are identified only by name)
178 #if !defined(__GLIBCXX__)
179 (*internals_pp)->registered_exception_translators.push_front(
180 [](std::exception_ptr p) -> void {
181 try {
182 if (p) std::rethrow_exception(p);
183 } catch (error_already_set &e) { e.restore(); return;
184 } catch (const builtin_exception &e) { e.set_error(); return;
185 }
186 }
187 );
188 #endif
189 } else {
190 if (!internals_pp) internals_pp = new internals*();
191 auto *&internals_ptr = *internals_pp;
192 internals_ptr = new internals();
193 #if defined(WITH_THREAD)
194 PyEval_InitThreads();
195 PyThreadState *tstate = PyThreadState_Get();
196 #if PY_VERSION_HEX >= 0x03070000
197 internals_ptr->tstate = PyThread_tss_alloc();
198 if (!internals_ptr->tstate || PyThread_tss_create(internals_ptr->tstate))
199 pybind11_fail("get_internals: could not successfully initialize the TSS key!");
200 PyThread_tss_set(internals_ptr->tstate, tstate);
201 #else
202 internals_ptr->tstate = PyThread_create_key();
203 if (internals_ptr->tstate == -1)
204 pybind11_fail("get_internals: could not successfully initialize the TLS key!");
205 PyThread_set_key_value(internals_ptr->tstate, tstate);
206 #endif
207 internals_ptr->istate = tstate->interp;
208 #endif
209 builtins[id] = capsule(internals_pp);
210 internals_ptr->registered_exception_translators.push_front(
211 [](std::exception_ptr p) -> void {
212 try {
213 if (p) std::rethrow_exception(p);
214 } catch (error_already_set &e) { e.restore(); return;
215 } catch (const builtin_exception &e) { e.set_error(); return;
216 } catch (const std::bad_alloc &e) { PyErr_SetString(PyExc_MemoryError, e.what()); return;
217 } catch (const std::domain_error &e) { PyErr_SetString(PyExc_ValueError, e.what()); return;
218 } catch (const std::invalid_argument &e) { PyErr_SetString(PyExc_ValueError, e.what()); return;
219 } catch (const std::length_error &e) { PyErr_SetString(PyExc_ValueError, e.what()); return;
220 } catch (const std::out_of_range &e) { PyErr_SetString(PyExc_IndexError, e.what()); return;
221 } catch (const std::range_error &e) { PyErr_SetString(PyExc_ValueError, e.what()); return;
222 } catch (const std::exception &e) { PyErr_SetString(PyExc_RuntimeError, e.what()); return;
223 } catch (...) {
224 PyErr_SetString(PyExc_RuntimeError, "Caught an unknown exception!");
225 return;
226 }
227 }
228 );
229 internals_ptr->static_property_type = make_static_property_type();
230 internals_ptr->default_metaclass = make_default_metaclass();
231 internals_ptr->instance_base = make_object_base_type(internals_ptr->default_metaclass);
232 }
233 return **internals_pp;
234 }
236 /// Works like `internals.registered_types_cpp`, but for module-local registered types:
237 inline type_map<type_info *> ®istered_local_types_cpp() {
238 static type_map<type_info *> locals{};
239 return locals;
240 }
242 /// Constructs a std::string with the given arguments, stores it in `internals`, and returns its
243 /// `c_str()`. Such strings objects have a long storage duration -- the internal strings are only
244 /// cleared when the program exits or after interpreter shutdown (when embedding), and so are
245 /// suitable for c-style strings needed by Python internals (such as PyTypeObject's tp_name).
246 template <typename... Args>
247 const char *c_str(Args &&...args) {
248 auto &strings = get_internals().static_strings;
249 strings.emplace_front(std::forward<Args>(args)...);
250 return strings.front().c_str();
251 }
253 NAMESPACE_END(detail)
255 /// Returns a named pointer that is shared among all extension modules (using the same
256 /// pybind11 version) running in the current interpreter. Names starting with underscores
257 /// are reserved for internal usage. Returns `nullptr` if no matching entry was found.
258 inline PYBIND11_NOINLINE void *get_shared_data(const std::string &name) {
259 auto &internals = detail::get_internals();
260 auto it = internals.shared_data.find(name);
261 return it != internals.shared_data.end() ? it->second : nullptr;
262 }
264 /// Set the shared data that can be later recovered by `get_shared_data()`.
265 inline PYBIND11_NOINLINE void *set_shared_data(const std::string &name, void *data) {
266 detail::get_internals().shared_data[name] = data;
267 return data;
268 }
270 /// Returns a typed reference to a shared data entry (by using `get_shared_data()`) if
271 /// such entry exists. Otherwise, a new object of default-constructible type `T` is
272 /// added to the shared data under the given name and a reference to it is returned.
273 template<typename T>
274 T &get_or_create_shared_data(const std::string &name) {
275 auto &internals = detail::get_internals();
276 auto it = internals.shared_data.find(name);
277 T *ptr = (T *) (it != internals.shared_data.end() ? it->second : nullptr);
278 if (!ptr) {
279 ptr = new T();
280 internals.shared_data[name] = ptr;
281 }
282 return *ptr;
283 }
285 NAMESPACE_END(PYBIND11_NAMESPACE)