ext/pybind11/include/pybind11/detail/internals.h

   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 #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
  47
  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 }
  62
  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 };
  72
  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
  79
  80 template <typename value_type>
  81 using type_map = std::unordered_map<std::type_index, value_type, type_hash, type_equal_to>;
  82
  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 };
  90
  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 };
 113
 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, type_align, 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 };
 139
 140 /// Tracks the `internals` and `type_info` ABI version independent of the main library version
 141 #define PYBIND11_INTERNALS_VERSION 3
 142
 143 /// On MSVC, debug and release builds are not ABI-compatible!
 144 #if defined(_MSC_VER) && defined(_DEBUG)
 145 #   define PYBIND11_BUILD_TYPE "_debug"
 146 #else
 147 #   define PYBIND11_BUILD_TYPE ""
 148 #endif
 149
 150 /// Let's assume that different compilers are ABI-incompatible.
 151 #if defined(_MSC_VER)
 152 #   define PYBIND11_COMPILER_TYPE "_msvc"
 153 #elif defined(__INTEL_COMPILER)
 154 #   define PYBIND11_COMPILER_TYPE "_icc"
 155 #elif defined(__clang__)
 156 #   define PYBIND11_COMPILER_TYPE "_clang"
 157 #elif defined(__PGI)
 158 #   define PYBIND11_COMPILER_TYPE "_pgi"
 159 #elif defined(__MINGW32__)
 160 #   define PYBIND11_COMPILER_TYPE "_mingw"
 161 #elif defined(__CYGWIN__)
 162 #   define PYBIND11_COMPILER_TYPE "_gcc_cygwin"
 163 #elif defined(__GNUC__)
 164 #   define PYBIND11_COMPILER_TYPE "_gcc"
 165 #else
 166 #   define PYBIND11_COMPILER_TYPE "_unknown"
 167 #endif
 168
 169 #if defined(_LIBCPP_VERSION)
 170 #  define PYBIND11_STDLIB "_libcpp"
 171 #elif defined(__GLIBCXX__) || defined(__GLIBCPP__)
 172 #  define PYBIND11_STDLIB "_libstdcpp"
 173 #else
 174 #  define PYBIND11_STDLIB ""
 175 #endif
 176
 177 /// On Linux/OSX, changes in __GXX_ABI_VERSION__ indicate ABI incompatibility.
 178 #if defined(__GXX_ABI_VERSION)
 179 #  define PYBIND11_BUILD_ABI "_cxxabi" PYBIND11_TOSTRING(__GXX_ABI_VERSION)
 180 #else
 181 #  define PYBIND11_BUILD_ABI ""
 182 #endif
 183
 184 #if defined(WITH_THREAD)
 185 #  define PYBIND11_INTERNALS_KIND ""
 186 #else
 187 #  define PYBIND11_INTERNALS_KIND "_without_thread"
 188 #endif
 189
 190 #define PYBIND11_INTERNALS_ID "__pybind11_internals_v" \
 191     PYBIND11_TOSTRING(PYBIND11_INTERNALS_VERSION) PYBIND11_INTERNALS_KIND PYBIND11_COMPILER_TYPE PYBIND11_STDLIB PYBIND11_BUILD_ABI PYBIND11_BUILD_TYPE "__"
 192
 193 #define PYBIND11_MODULE_LOCAL_ID "__pybind11_module_local_v" \
 194     PYBIND11_TOSTRING(PYBIND11_INTERNALS_VERSION) PYBIND11_INTERNALS_KIND PYBIND11_COMPILER_TYPE PYBIND11_STDLIB PYBIND11_BUILD_ABI PYBIND11_BUILD_TYPE "__"
 195
 196 /// Each module locally stores a pointer to the `internals` data. The data
 197 /// itself is shared among modules with the same `PYBIND11_INTERNALS_ID`.
 198 inline internals **&get_internals_pp() {
 199     static internals **internals_pp = nullptr;
 200     return internals_pp;
 201 }
 202
 203 inline void translate_exception(std::exception_ptr p) {
 204     try {
 205         if (p) std::rethrow_exception(p);
 206     } catch (error_already_set &e)           { e.restore();                                    return;
 207     } catch (const builtin_exception &e)     { e.set_error();                                  return;
 208     } catch (const std::bad_alloc &e)        { PyErr_SetString(PyExc_MemoryError,   e.what()); return;
 209     } catch (const std::domain_error &e)     { PyErr_SetString(PyExc_ValueError,    e.what()); return;
 210     } catch (const std::invalid_argument &e) { PyErr_SetString(PyExc_ValueError,    e.what()); return;
 211     } catch (const std::length_error &e)     { PyErr_SetString(PyExc_ValueError,    e.what()); return;
 212     } catch (const std::out_of_range &e)     { PyErr_SetString(PyExc_IndexError,    e.what()); return;
 213     } catch (const std::range_error &e)      { PyErr_SetString(PyExc_ValueError,    e.what()); return;
 214     } catch (const std::exception &e)        { PyErr_SetString(PyExc_RuntimeError,  e.what()); return;
 215     } catch (...) {
 216         PyErr_SetString(PyExc_RuntimeError, "Caught an unknown exception!");
 217         return;
 218     }
 219 }
 220
 221 #if !defined(__GLIBCXX__)
 222 inline void translate_local_exception(std::exception_ptr p) {
 223     try {
 224         if (p) std::rethrow_exception(p);
 225     } catch (error_already_set &e)       { e.restore();   return;
 226     } catch (const builtin_exception &e) { e.set_error(); return;
 227     }
 228 }
 229 #endif
 230
 231 /// Return a reference to the current `internals` data
 232 PYBIND11_NOINLINE inline internals &get_internals() {
 233     auto **&internals_pp = get_internals_pp();
 234     if (internals_pp && *internals_pp)
 235         return **internals_pp;
 236
 237     // Ensure that the GIL is held since we will need to make Python calls.
 238     // Cannot use py::gil_scoped_acquire here since that constructor calls get_internals.
 239     struct gil_scoped_acquire_local {
 240         gil_scoped_acquire_local() : state (PyGILState_Ensure()) {}
 241         ~gil_scoped_acquire_local() { PyGILState_Release(state); }
 242         const PyGILState_STATE state;
 243     } gil;
 244
 245     constexpr auto *id = PYBIND11_INTERNALS_ID;
 246     auto builtins = handle(PyEval_GetBuiltins());
 247     if (builtins.contains(id) && isinstance<capsule>(builtins[id])) {
 248         internals_pp = static_cast<internals **>(capsule(builtins[id]));
 249
 250         // We loaded builtins through python's builtins, which means that our `error_already_set`
 251         // and `builtin_exception` may be different local classes than the ones set up in the
 252         // initial exception translator, below, so add another for our local exception classes.
 253         //
 254         // libstdc++ doesn't require this (types there are identified only by name)
 255 #if !defined(__GLIBCXX__)
 256         (*internals_pp)->registered_exception_translators.push_front(&translate_local_exception);
 257 #endif
 258     } else {
 259         if (!internals_pp) internals_pp = new internals*();
 260         auto *&internals_ptr = *internals_pp;
 261         internals_ptr = new internals();
 262 #if defined(WITH_THREAD)
 263         PyEval_InitThreads();
 264         PyThreadState *tstate = PyThreadState_Get();
 265         #if PY_VERSION_HEX >= 0x03070000
 266             internals_ptr->tstate = PyThread_tss_alloc();
 267             if (!internals_ptr->tstate || PyThread_tss_create(internals_ptr->tstate))
 268                 pybind11_fail("get_internals: could not successfully initialize the TSS key!");
 269             PyThread_tss_set(internals_ptr->tstate, tstate);
 270         #else
 271             internals_ptr->tstate = PyThread_create_key();
 272             if (internals_ptr->tstate == -1)
 273                 pybind11_fail("get_internals: could not successfully initialize the TLS key!");
 274             PyThread_set_key_value(internals_ptr->tstate, tstate);
 275         #endif
 276         internals_ptr->istate = tstate->interp;
 277 #endif
 278         builtins[id] = capsule(internals_pp);
 279         internals_ptr->registered_exception_translators.push_front(&translate_exception);
 280         internals_ptr->static_property_type = make_static_property_type();
 281         internals_ptr->default_metaclass = make_default_metaclass();
 282         internals_ptr->instance_base = make_object_base_type(internals_ptr->default_metaclass);
 283     }
 284     return **internals_pp;
 285 }
 286
 287 /// Works like `internals.registered_types_cpp`, but for module-local registered types:
 288 inline type_map<type_info *> &registered_local_types_cpp() {
 289     static type_map<type_info *> locals{};
 290     return locals;
 291 }
 292
 293 /// Constructs a std::string with the given arguments, stores it in `internals`, and returns its
 294 /// `c_str()`.  Such strings objects have a long storage duration -- the internal strings are only
 295 /// cleared when the program exits or after interpreter shutdown (when embedding), and so are
 296 /// suitable for c-style strings needed by Python internals (such as PyTypeObject's tp_name).
 297 template <typename... Args>
 298 const char *c_str(Args &&...args) {
 299     auto &strings = get_internals().static_strings;
 300     strings.emplace_front(std::forward<Args>(args)...);
 301     return strings.front().c_str();
 302 }
 303
 304 NAMESPACE_END(detail)
 305
 306 /// Returns a named pointer that is shared among all extension modules (using the same
 307 /// pybind11 version) running in the current interpreter. Names starting with underscores
 308 /// are reserved for internal usage. Returns `nullptr` if no matching entry was found.
 309 inline PYBIND11_NOINLINE void *get_shared_data(const std::string &name) {
 310     auto &internals = detail::get_internals();
 311     auto it = internals.shared_data.find(name);
 312     return it != internals.shared_data.end() ? it->second : nullptr;
 313 }
 314
 315 /// Set the shared data that can be later recovered by `get_shared_data()`.
 316 inline PYBIND11_NOINLINE void *set_shared_data(const std::string &name, void *data) {
 317     detail::get_internals().shared_data[name] = data;
 318     return data;
 319 }
 320
 321 /// Returns a typed reference to a shared data entry (by using `get_shared_data()`) if
 322 /// such entry exists. Otherwise, a new object of default-constructible type `T` is
 323 /// added to the shared data under the given name and a reference to it is returned.
 324 template<typename T>
 325 T &get_or_create_shared_data(const std::string &name) {
 326     auto &internals = detail::get_internals();
 327     auto it = internals.shared_data.find(name);
 328     T *ptr = (T *) (it != internals.shared_data.end() ? it->second : nullptr);
 329     if (!ptr) {
 330         ptr = new T();
 331         internals.shared_data[name] = ptr;
 332     }
 333     return *ptr;
 334 }
 335
 336 NAMESPACE_END(PYBIND11_NAMESPACE)