/*
    pybind11/detail/internals.h: Internal data structure and related functions

    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 "common.h"

#if defined(WITH_THREAD) && defined(PYBIND11_SIMPLE_GIL_MANAGEMENT)
#    include "../gil.h"
#endif

#include "../pytypes.h"

#include <exception>

/// Tracks the `internals` and `type_info` ABI version independent of the main library version.
///
/// Some portions of the code use an ABI that is conditional depending on this
/// version number.  That allows ABI-breaking changes to be "pre-implemented".
/// Once the default version number is incremented, the conditional logic that
/// no longer applies can be removed.  Additionally, users that need not
/// maintain ABI compatibility can increase the version number in order to take
/// advantage of any functionality/efficiency improvements that depend on the
/// newer ABI.
///
/// WARNING: If you choose to manually increase the ABI version, note that
/// pybind11 may not be tested as thoroughly with a non-default ABI version, and
/// further ABI-incompatible changes may be made before the ABI is officially
/// changed to the new version.
#ifndef PYBIND11_INTERNALS_VERSION
#    define PYBIND11_INTERNALS_VERSION 4
#endif

PYBIND11_NAMESPACE_BEGIN(PYBIND11_NAMESPACE)

using ExceptionTranslator = void (*)(std::exception_ptr);

PYBIND11_NAMESPACE_BEGIN(detail)

// Forward declarations
inline PyTypeObject *make_static_property_type();
inline PyTypeObject *make_default_metaclass();
inline PyObject *make_object_base_type(PyTypeObject *metaclass);

// The old Python Thread Local Storage (TLS) API is deprecated in Python 3.7 in favor of the new
// Thread Specific Storage (TSS) API.
#if PY_VERSION_HEX >= 0x03070000
// Avoid unnecessary allocation of `Py_tss_t`, since we cannot use
// `Py_LIMITED_API` anyway.
#    if PYBIND11_INTERNALS_VERSION > 4
#        define PYBIND11_TLS_KEY_REF Py_tss_t &
#        if defined(__GNUC__) && !defined(__INTEL_COMPILER)
// Clang on macOS warns due to `Py_tss_NEEDS_INIT` not specifying an initializer
// for every field.
#            define PYBIND11_TLS_KEY_INIT(var)                                                    \
                _Pragma("GCC diagnostic push")                                         /**/       \
                    _Pragma("GCC diagnostic ignored \"-Wmissing-field-initializers\"") /**/       \
                    Py_tss_t var                                                                  \
                    = Py_tss_NEEDS_INIT;                                                          \
                _Pragma("GCC diagnostic pop")
#        else
#            define PYBIND11_TLS_KEY_INIT(var) Py_tss_t var = Py_tss_NEEDS_INIT;
#        endif
#        define PYBIND11_TLS_KEY_CREATE(var) (PyThread_tss_create(&(var)) == 0)
#        define PYBIND11_TLS_GET_VALUE(key) PyThread_tss_get(&(key))
#        define PYBIND11_TLS_REPLACE_VALUE(key, value) PyThread_tss_set(&(key), (value))
#        define PYBIND11_TLS_DELETE_VALUE(key) PyThread_tss_set(&(key), nullptr)
#        define PYBIND11_TLS_FREE(key) PyThread_tss_delete(&(key))
#    else
#        define PYBIND11_TLS_KEY_REF Py_tss_t *
#        define PYBIND11_TLS_KEY_INIT(var) Py_tss_t *var = nullptr;
#        define PYBIND11_TLS_KEY_CREATE(var)                                                      \
            (((var) = PyThread_tss_alloc()) != nullptr && (PyThread_tss_create((var)) == 0))
#        define PYBIND11_TLS_GET_VALUE(key) PyThread_tss_get((key))
#        define PYBIND11_TLS_REPLACE_VALUE(key, value) PyThread_tss_set((key), (value))
#        define PYBIND11_TLS_DELETE_VALUE(key) PyThread_tss_set((key), nullptr)
#        define PYBIND11_TLS_FREE(key) PyThread_tss_free(key)
#    endif
#else
// Usually an int but a long on Cygwin64 with Python 3.x
#    define PYBIND11_TLS_KEY_REF decltype(PyThread_create_key())
#    define PYBIND11_TLS_KEY_INIT(var) PYBIND11_TLS_KEY_REF var = 0;
#    define PYBIND11_TLS_KEY_CREATE(var) (((var) = PyThread_create_key()) != -1)
#    define PYBIND11_TLS_GET_VALUE(key) PyThread_get_key_value((key))
#    if defined(PYPY_VERSION)
// On CPython < 3.4 and on PyPy, `PyThread_set_key_value` strangely does not set
// the value if it has already been set.  Instead, it must first be deleted and
// then set again.
inline void tls_replace_value(PYBIND11_TLS_KEY_REF key, void *value) {
    PyThread_delete_key_value(key);
    PyThread_set_key_value(key, value);
}
#        define PYBIND11_TLS_DELETE_VALUE(key) PyThread_delete_key_value(key)
#        define PYBIND11_TLS_REPLACE_VALUE(key, value)                                            \
            ::pybind11::detail::tls_replace_value((key), (value))
#    else
#        define PYBIND11_TLS_DELETE_VALUE(key) PyThread_set_key_value((key), nullptr)
#        define PYBIND11_TLS_REPLACE_VALUE(key, value) PyThread_set_key_value((key), (value))
#    endif
#    define PYBIND11_TLS_FREE(key) (void) key
#endif

// Python loads modules by default with dlopen with the RTLD_LOCAL flag; under libc++ and possibly
// other STLs, this means `typeid(A)` from one module won't equal `typeid(A)` from another module
// even when `A` is the same, non-hidden-visibility type (e.g. from a common include).  Under
// libstdc++, this doesn't happen: equality and the type_index hash are based on the type name,
// which works.  If not under a known-good stl, provide our own name-based hash and equality
// functions that use the type name.
#if defined(__GLIBCXX__)
inline bool same_type(const std::type_info &lhs, const std::type_info &rhs) { return lhs == rhs; }
using type_hash = std::hash<std::type_index>;
using type_equal_to = std::equal_to<std::type_index>;
#else
inline bool same_type(const std::type_info &lhs, const std::type_info &rhs) {
    return lhs.name() == rhs.name() || std::strcmp(lhs.name(), rhs.name()) == 0;
}

struct type_hash {
    size_t operator()(const std::type_index &t) const {
        size_t hash = 5381;
        const char *ptr = t.name();
        while (auto c = static_cast<unsigned char>(*ptr++)) {
            hash = (hash * 33) ^ c;
        }
        return hash;
    }
};

struct type_equal_to {
    bool operator()(const std::type_index &lhs, const std::type_index &rhs) const {
        return lhs.name() == rhs.name() || std::strcmp(lhs.name(), rhs.name()) == 0;
    }
};
#endif

template <typename value_type>
using type_map = std::unordered_map<std::type_index, value_type, type_hash, type_equal_to>;

struct override_hash {
    inline size_t operator()(const std::pair<const PyObject *, const char *> &v) const {
        size_t value = std::hash<const void *>()(v.first);
        value ^= std::hash<const void *>()(v.second) + 0x9e3779b9 + (value << 6) + (value >> 2);
        return value;
    }
};

/// Internal data structure used to track registered instances and types.
/// Whenever binary incompatible changes are made to this structure,
/// `PYBIND11_INTERNALS_VERSION` must be incremented.
struct internals {
    // std::type_index -> pybind11's type information
    type_map<type_info *> registered_types_cpp;
    // PyTypeObject* -> base type_info(s)
    std::unordered_map<PyTypeObject *, std::vector<type_info *>> registered_types_py;
    std::unordered_multimap<const void *, instance *> registered_instances; // void * -> instance*
    std::unordered_set<std::pair<const PyObject *, const char *>, override_hash>
        inactive_override_cache;
    type_map<std::vector<bool (*)(PyObject *, void *&)>> direct_conversions;
    std::unordered_map<const PyObject *, std::vector<PyObject *>> patients;
    std::forward_list<ExceptionTranslator> registered_exception_translators;
    std::unordered_map<std::string, void *> shared_data; // Custom data to be shared across
                                                         // extensions
#if PYBIND11_INTERNALS_VERSION == 4
    std::vector<PyObject *> unused_loader_patient_stack_remove_at_v5;
#endif
    std::forward_list<std::string> static_strings; // Stores the std::strings backing
                                                   // detail::c_str()
    PyTypeObject *static_property_type;
    PyTypeObject *default_metaclass;
    PyObject *instance_base;
#if defined(WITH_THREAD)
    // Unused if PYBIND11_SIMPLE_GIL_MANAGEMENT is defined:
    PYBIND11_TLS_KEY_INIT(tstate)
#    if PYBIND11_INTERNALS_VERSION > 4
    PYBIND11_TLS_KEY_INIT(loader_life_support_tls_key)
#    endif // PYBIND11_INTERNALS_VERSION > 4
    // Unused if PYBIND11_SIMPLE_GIL_MANAGEMENT is defined:
    PyInterpreterState *istate = nullptr;
    ~internals() {
#    if PYBIND11_INTERNALS_VERSION > 4
        PYBIND11_TLS_FREE(loader_life_support_tls_key);
#    endif // PYBIND11_INTERNALS_VERSION > 4

        // This destructor is called *after* Py_Finalize() in finalize_interpreter().
        // That *SHOULD BE* fine. The following details what happens when PyThread_tss_free is
        // called. PYBIND11_TLS_FREE is PyThread_tss_free on python 3.7+. On older python, it does
        // nothing. PyThread_tss_free calls PyThread_tss_delete and PyMem_RawFree.
        // PyThread_tss_delete just calls TlsFree (on Windows) or pthread_key_delete (on *NIX).
        // Neither of those have anything to do with CPython internals. PyMem_RawFree *requires*
        // that the `tstate` be allocated with the CPython allocator.
        PYBIND11_TLS_FREE(tstate);
    }
#endif
};

/// Additional type information which does not fit into the PyTypeObject.
/// Changes to this struct also require bumping `PYBIND11_INTERNALS_VERSION`.
struct type_info {
    PyTypeObject *type;
    const std::type_info *cpptype;
    size_t type_size, type_align, holder_size_in_ptrs;
    void *(*operator_new)(size_t);
    void (*init_instance)(instance *, const void *);
    void (*dealloc)(value_and_holder &v_h);
    std::vector<PyObject *(*) (PyObject *, PyTypeObject *)> implicit_conversions;
    std::vector<std::pair<const std::type_info *, void *(*) (void *)>> implicit_casts;
    std::vector<bool (*)(PyObject *, void *&)> *direct_conversions;
    buffer_info *(*get_buffer)(PyObject *, void *) = nullptr;
    void *get_buffer_data = nullptr;
    void *(*module_local_load)(PyObject *, const type_info *) = nullptr;
    /* A simple type never occurs as a (direct or indirect) parent
     * of a class that makes use of multiple inheritance.
     * A type can be simple even if it has non-simple ancestors as long as it has no descendants.
     */
    bool simple_type : 1;
    /* True if there is no multiple inheritance in this type's inheritance tree */
    bool simple_ancestors : 1;
    /* for base vs derived holder_type checks */
    bool default_holder : 1;
    /* true if this is a type registered with py::module_local */
    bool module_local : 1;
};

/// On MSVC, debug and release builds are not ABI-compatible!
#if defined(_MSC_VER) && defined(_DEBUG)
#    define PYBIND11_BUILD_TYPE "_debug"
#else
#    define PYBIND11_BUILD_TYPE ""
#endif

/// Let's assume that different compilers are ABI-incompatible.
/// A user can manually set this string if they know their
/// compiler is compatible.
#ifndef PYBIND11_COMPILER_TYPE
#    if defined(_MSC_VER)
#        define PYBIND11_COMPILER_TYPE "_msvc"
#    elif defined(__INTEL_COMPILER)
#        define PYBIND11_COMPILER_TYPE "_icc"
#    elif defined(__clang__)
#        define PYBIND11_COMPILER_TYPE "_clang"
#    elif defined(__PGI)
#        define PYBIND11_COMPILER_TYPE "_pgi"
#    elif defined(__MINGW32__)
#        define PYBIND11_COMPILER_TYPE "_mingw"
#    elif defined(__CYGWIN__)
#        define PYBIND11_COMPILER_TYPE "_gcc_cygwin"
#    elif defined(__GNUC__)
#        define PYBIND11_COMPILER_TYPE "_gcc"
#    else
#        define PYBIND11_COMPILER_TYPE "_unknown"
#    endif
#endif

/// Also standard libs
#ifndef PYBIND11_STDLIB
#    if defined(_LIBCPP_VERSION)
#        define PYBIND11_STDLIB "_libcpp"
#    elif defined(__GLIBCXX__) || defined(__GLIBCPP__)
#        define PYBIND11_STDLIB "_libstdcpp"
#    else
#        define PYBIND11_STDLIB ""
#    endif
#endif

/// On Linux/OSX, changes in __GXX_ABI_VERSION__ indicate ABI incompatibility.
#ifndef PYBIND11_BUILD_ABI
#    if defined(__GXX_ABI_VERSION)
#        define PYBIND11_BUILD_ABI "_cxxabi" PYBIND11_TOSTRING(__GXX_ABI_VERSION)
#    else
#        define PYBIND11_BUILD_ABI ""
#    endif
#endif

#ifndef PYBIND11_INTERNALS_KIND
#    if defined(WITH_THREAD)
#        define PYBIND11_INTERNALS_KIND ""
#    else
#        define PYBIND11_INTERNALS_KIND "_without_thread"
#    endif
#endif

#define PYBIND11_INTERNALS_ID                                                                     \
    "__pybind11_internals_v" PYBIND11_TOSTRING(PYBIND11_INTERNALS_VERSION)                        \
        PYBIND11_INTERNALS_KIND PYBIND11_COMPILER_TYPE PYBIND11_STDLIB PYBIND11_BUILD_ABI         \
            PYBIND11_BUILD_TYPE "__"

#define PYBIND11_MODULE_LOCAL_ID                                                                  \
    "__pybind11_module_local_v" PYBIND11_TOSTRING(PYBIND11_INTERNALS_VERSION)                     \
        PYBIND11_INTERNALS_KIND PYBIND11_COMPILER_TYPE PYBIND11_STDLIB PYBIND11_BUILD_ABI         \
            PYBIND11_BUILD_TYPE "__"

/// Each module locally stores a pointer to the `internals` data. The data
/// itself is shared among modules with the same `PYBIND11_INTERNALS_ID`.
inline internals **&get_internals_pp() {
    static internals **internals_pp = nullptr;
    return internals_pp;
}

// forward decl
inline void translate_exception(std::exception_ptr);

template <class T,
          enable_if_t<std::is_same<std::nested_exception, remove_cvref_t<T>>::value, int> = 0>
bool handle_nested_exception(const T &exc, const std::exception_ptr &p) {
    std::exception_ptr nested = exc.nested_ptr();
    if (nested != nullptr && nested != p) {
        translate_exception(nested);
        return true;
    }
    return false;
}

template <class T,
          enable_if_t<!std::is_same<std::nested_exception, remove_cvref_t<T>>::value, int> = 0>
bool handle_nested_exception(const T &exc, const std::exception_ptr &p) {
    if (const auto *nep = dynamic_cast<const std::nested_exception *>(std::addressof(exc))) {
        return handle_nested_exception(*nep, p);
    }
    return false;
}

inline bool raise_err(PyObject *exc_type, const char *msg) {
    if (PyErr_Occurred()) {
        raise_from(exc_type, msg);
        return true;
    }
    PyErr_SetString(exc_type, msg);
    return false;
}

inline void translate_exception(std::exception_ptr p) {
    if (!p) {
        return;
    }
    try {
        std::rethrow_exception(p);
    } catch (error_already_set &e) {
        handle_nested_exception(e, p);
        e.restore();