/*
    pybind11/pybind11.h: Main header file of the C++11 python
    binding generator library

    Copyright (c) 2016 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 "detail/class.h"
#include "detail/init.h"
#include "attr.h"
#include "gil.h"
#include "options.h"

#include <cstdlib>
#include <cstring>
#include <memory>
#include <new>
#include <string>
#include <utility>
#include <vector>

#if defined(__cpp_lib_launder) && !(defined(_MSC_VER) && (_MSC_VER < 1914))
#    define PYBIND11_STD_LAUNDER std::launder
#    define PYBIND11_HAS_STD_LAUNDER 1
#else
#    define PYBIND11_STD_LAUNDER
#    define PYBIND11_HAS_STD_LAUNDER 0
#endif
#if defined(__GNUG__) && !defined(__clang__)
#    include <cxxabi.h>
#endif

/* https://stackoverflow.com/questions/46798456/handling-gccs-noexcept-type-warning
   This warning is about ABI compatibility, not code health.
   It is only actually needed in a couple places, but apparently GCC 7 "generates this warning if
   and only if the first template instantiation ... involves noexcept" [stackoverflow], therefore
   it could get triggered from seemingly random places, depending on user code.
   No other GCC version generates this warning.
 */
#if defined(__GNUC__) && __GNUC__ == 7
#    pragma GCC diagnostic push
#    pragma GCC diagnostic ignored "-Wnoexcept-type"
#endif

PYBIND11_NAMESPACE_BEGIN(PYBIND11_NAMESPACE)

PYBIND11_NAMESPACE_BEGIN(detail)

// Apply all the extensions translators from a list
// Return true if one of the translators completed without raising an exception
// itself. Return of false indicates that if there are other translators
// available, they should be tried.
inline bool apply_exception_translators(std::forward_list<ExceptionTranslator> &translators) {
    auto last_exception = std::current_exception();

    for (auto &translator : translators) {
        try {
            translator(last_exception);
            return true;
        } catch (...) {
            last_exception = std::current_exception();
        }
    }
    return false;
}

#if defined(_MSC_VER)
#    define PYBIND11_COMPAT_STRDUP _strdup
#else
#    define PYBIND11_COMPAT_STRDUP strdup
#endif

PYBIND11_NAMESPACE_END(detail)

/// Wraps an arbitrary C++ function/method/lambda function/.. into a callable Python object
class cpp_function : public function {
public:
    cpp_function() = default;
    // NOLINTNEXTLINE(google-explicit-constructor)
    cpp_function(std::nullptr_t) {}

    /// Construct a cpp_function from a vanilla function pointer
    template <typename Return, typename... Args, typename... Extra>
    // NOLINTNEXTLINE(google-explicit-constructor)
    cpp_function(Return (*f)(Args...), const Extra &...extra) {
        initialize(f, f, extra...);
    }

    /// Construct a cpp_function from a lambda function (possibly with internal state)
    template <typename Func,
              typename... Extra,
              typename = detail::enable_if_t<detail::is_lambda<Func>::value>>
    // NOLINTNEXTLINE(google-explicit-constructor)
    cpp_function(Func &&f, const Extra &...extra) {
        initialize(
            std::forward<Func>(f), (detail::function_signature_t<Func> *) nullptr, extra...);
    }

    /// Construct a cpp_function from a class method (non-const, no ref-qualifier)
    template <typename Return, typename Class, typename... Arg, typename... Extra>
    // NOLINTNEXTLINE(google-explicit-constructor)
    cpp_function(Return (Class::*f)(Arg...), const Extra &...extra) {
        initialize(
            [f](Class *c, Arg... args) -> Return { return (c->*f)(std::forward<Arg>(args)...); },
            (Return(*)(Class *, Arg...)) nullptr,
            extra...);
    }

    /// Construct a cpp_function from a class method (non-const, lvalue ref-qualifier)
    /// A copy of the overload for non-const functions without explicit ref-qualifier
    /// but with an added `&`.
    template <typename Return, typename Class, typename... Arg, typename... Extra>
    // NOLINTNEXTLINE(google-explicit-constructor)
    cpp_function(Return (Class::*f)(Arg...) &, const Extra &...extra) {
        initialize(
            [f](Class *c, Arg... args) -> Return { return (c->*f)(std::forward<Arg>(args)...); },
            (Return(*)(Class *, Arg...)) nullptr,
            extra...);
    }

    /// Construct a cpp_function from a class method (const, no ref-qualifier)
    template <typename Return, typename Class, typename... Arg, typename... Extra>
    // NOLINTNEXTLINE(google-explicit-constructor)
    cpp_function(Return (Class::*f)(Arg...) const, const Extra &...extra) {
        initialize([f](const Class *c,
                       Arg... args) -> Return { return (c->*f)(std::forward<Arg>(args)...); },
                   (Return(*)(const Class *, Arg...)) nullptr,
                   extra...);
    }

    /// Construct a cpp_function from a class method (const, lvalue ref-qualifier)
    /// A copy of the overload for const functions without explicit ref-qualifier
    /// but with an added `&`.
    template <typename Return, typename Class, typename... Arg, typename... Extra>
    // NOLINTNEXTLINE(google-explicit-constructor)
    cpp_function(Return (Class::*f)(Arg...) const &, const Extra &...extra) {
        initialize([f](const Class *c,
                       Arg... args) -> Return { return (c->*f)(std::forward<Arg>(args)...); },
                   (Return(*)(const Class *, Arg...)) nullptr,
                   extra...);
    }

    /// Return the function name
    object name() const { return attr("__name__"); }

protected:
    struct InitializingFunctionRecordDeleter {
        // `destruct(function_record, false)`: `initialize_generic` copies strings and
        // takes care of cleaning up in case of exceptions. So pass `false` to `free_strings`.
        void operator()(detail::function_record *rec) { destruct(rec, false); }
    };
    using unique_function_record
        = std::unique_ptr<detail::function_record, InitializingFunctionRecordDeleter>;

    /// Space optimization: don't inline this frequently instantiated fragment
    PYBIND11_NOINLINE unique_function_record make_function_record() {
        return unique_function_record(new detail::function_record());
    }

    /// Special internal constructor for functors, lambda functions, etc.
    template <typename Func, typename Return, typename... Args, typename... Extra>
    void initialize(Func &&f, Return (*)(Args...), const Extra &...extra) {
        using namespace detail;
        struct capture {
            remove_reference_t<Func> f;
        };

        /* Store the function including any extra state it might have (e.g. a lambda capture
         * object) */
        // The unique_ptr makes sure nothing is leaked in case of an exception.
        auto unique_rec = make_function_record();
        auto *rec = unique_rec.get();

        /* Store the capture object directly in the function record if there is enough space */
        if (PYBIND11_SILENCE_MSVC_C4127(sizeof(capture) <= sizeof(rec->data))) {
            /* Without these pragmas, GCC warns that there might not be
               enough space to use the placement new operator. However, the
               'if' statement above ensures that this is the case. */
#if defined(__GNUG__) && __GNUC__ >= 6 && !defined(__clang__) && !defined(__INTEL_COMPILER)
#    pragma GCC diagnostic push
#    pragma GCC diagnostic ignored "-Wplacement-new"
#endif
            new ((capture *) &rec->data) capture{std::forward<Func>(f)};
#if defined(__GNUG__) && __GNUC__ >= 6 && !defined(__clang__) && !defined(__INTEL_COMPILER)
#    pragma GCC diagnostic pop
#endif
#if defined(__GNUG__) && !PYBIND11_HAS_STD_LAUNDER && !defined(__INTEL_COMPILER)
#    pragma GCC diagnostic push
#    pragma GCC diagnostic ignored "-Wstrict-aliasing"
#endif
            // UB without std::launder, but without breaking ABI and/or
            // a significant refactoring it's "impossible" to solve.
            if (!std::is_trivially_destructible<capture>::value) {
                rec->free_data = [](function_record *r) {
                    auto data = PYBIND11_STD_LAUNDER((capture *) &r->data);
                    (void) data;
                    data->~capture();
                };
            }
#if defined(__GNUG__) && !PYBIND11_HAS_STD_LAUNDER && !defined(__INTEL_COMPILER)
#    pragma GCC diagnostic pop
#endif
        } else {
            rec->data[0] = new capture{std::forward<Func>(f)};
            rec->free_data = [](function_record *r) { delete ((capture *) r->data[0]); };
        }

        /* Type casters for the function arguments and return value */
        using cast_in = argument_loader<Args...>;
        using cast_out
            = make_caster<conditional_t<std::is_void<Return>::value, void_type, Return>>;

        static_assert(
            expected_num_args<Extra...>(
                sizeof...(Args), cast_in::args_pos >= 0, cast_in::has_kwargs),
            "The number of argument annotations does not match the number of function arguments");

        /* Dispatch code which converts function arguments and performs the actual function call */
        rec->impl = [](function_call &call) -> handle {
            cast_in args_converter;

            /* Try to cast the function arguments into the C++ domain */
            if (!args_converter.load_args(call)) {
                return PYBIND11_TRY_NEXT_OVERLOAD;
            }

            /* Invoke call policy pre-call hook */
            process_attributes<Extra...>::precall(call);

            /* Get a pointer to the capture object */
            const auto *data = (sizeof(capture) <= sizeof(call.func.data) ? &call.func.data
                                                                          : call.func.data[0]);
            auto *cap = const_cast<capture *>(reinterpret_cast<const capture *>(data));

            /* Override policy for rvalues -- usually to enforce rvp::move on an rvalue */
            return_value_policy policy
                = return_value_policy_override<Return>::policy(call.func.policy);

            /* Function scope guard -- defaults to the compile-to-nothing `void_type` */
            using Guard = extract_guard_t<Extra...>;

            /* Perform the function call */
            handle result
                = cast_out::cast(std::move(args_converter).template call<Return, Guard>(cap->f),
                                 policy,
                                 call.parent);

            /* Invoke call policy post-call hook */
            process_attributes<Extra...>::postcall(call, result);

            return result;
        };

        rec->nargs_pos = cast_in::args_pos >= 0
                             ? static_cast<std::uint16_t>(cast_in::args_pos)
                             : sizeof...(Args) - cast_in::has_kwargs; // Will get reduced more if
                                                                      // we have a kw_only
        rec->has_args = cast_in::args_pos >= 0;
        rec->has_kwargs = cast_in::has_kwargs;

        /* Process any user-provided function attributes */
        process_attributes<Extra...>::init(extra..., rec);

        {
            constexpr bool has_kw_only_args = any_of<std::is_same<kw_only, Extra>...>::value,
                           has_pos_only_args = any_of<std::is_same<pos_only, Extra>...>::value,
                           has_arg_annotations = any_of<is_keyword<Extra>...>::value;
            static_assert(has_arg_annotations || !has_kw_only_args,
                          "py::kw_only requires the use of argument annotations");
            static_assert(has_arg_annotations || !has_pos_only_args,
                          "py::pos_only requires the use of argument annotations (for docstrings "
                          "and aligning the annotations to the argument)");

            static_assert(constexpr_sum(is_kw_only<Extra>::value...) <= 1,
                          "py::kw_only may be specified only once");
            static_assert(constexpr_sum(is_pos_only<Extra>::value...) <= 1,
                          "py::pos_only may be specified only once");
            constexpr auto kw_only_pos = constexpr_first<is_kw_only, Extra...>();
            constexpr auto pos_only_pos = constexpr_first<is_pos_only, Extra...>();
            static_assert(!(has_kw_only_args && has_pos_only_args) || pos_only_pos < kw_only_pos,
                          "py::pos_only must come before py::kw_only");
        }

        /* Generate a readable signature describing the function's arguments and return
           value types */
        static constexpr auto signature
            = const_name("(") + cast_in::arg_names + const_name(") -> ") + cast_out::name;
        PYBIND11_DESCR_CONSTEXPR auto types = decltype(signature)::types();

        /* Register the function with Python from generic (non-templated) code */
        // Pass on the ownership over the `unique_rec` to `initialize_generic`. `rec` stays valid.
        initialize_generic(std::move(unique_rec), signature.text, types.data(), sizeof...(Args));

        /* Stash some additional information used by an important optimization in 'functional.h' */
        using FunctionType = Return (*)(Args...);
        constexpr bool is_function_ptr
            = std::is_convertible<Func, FunctionType>::value && sizeof(capture) == sizeof(void *);
        if (is_function_ptr) {
            rec->is_stateless = true;
            rec->data[1]
                = const_cast<void *>(reinterpret_cast<const void *>(&typeid(FunctionType)));
        }
    }

    // Utility class that keeps track of all duplicated strings, and cleans them up in its
    // destructor, unless they are released. Basically a RAII-solution to deal with exceptions
    // along the way.
    class strdup_guard {
    public:
        strdup_guard() = default;
        strdup_guard(const strdup_guard &) = delete;
        strdup_guard &operator=(const strdup_guard &) = delete;

        ~strdup_guard() {
            for (auto *s : strings) {
                std::free(s);
            }
        }
        char *operator()(const char *s) {
            auto *t = PYBIND11_COMPAT_STRDUP(s);
            strings.push_back(t);
            return t;
        }
        void release() { strings.clear(); }

    private:
        std::vector<char *> strings;
    };

    /// Register a function call with Python (generic non-templated code goes here)
    void initialize_generic(unique_function_record &&unique_rec,
                            const char *text,
                            const std::type_info *const *types,
                            size_t args) {
        // Do NOT receive `unique_rec` by value. If this function fails to move out the unique_ptr,
        // we do not want this to destruct the pointer. `initialize` (the caller) still relies on
        // the pointee being alive after this call. Only move out if a `capsule` is going to keep
        // it alive.
        auto *rec = unique_rec.get();