// Copyright Antony Polukhin, 2016-2024.
//
// Distributed under the Boost Software License, Version 1.0. (See
// accompanying file LICENSE_1_0.txt or copy at
// http://www.boost.org/LICENSE_1_0.txt)

#ifndef BOOST_STACKTRACE_STACKTRACE_HPP
#define BOOST_STACKTRACE_STACKTRACE_HPP

#include <boost/config.hpp>
#ifdef BOOST_HAS_PRAGMA_ONCE
#   pragma once
#endif

#include <boost/core/no_exceptions_support.hpp>
#include <boost/container_hash/hash_fwd.hpp>

#include <iosfwd>
#include <string>
#include <vector>

#ifndef BOOST_NO_CXX11_HDR_TYPE_TRAITS
#   include <type_traits>
#endif

#include <boost/stacktrace/stacktrace_fwd.hpp>
#include <boost/stacktrace/safe_dump_to.hpp>
#include <boost/stacktrace/detail/frame_decl.hpp>
#include <boost/stacktrace/frame.hpp>

#ifdef BOOST_INTEL
#   pragma warning(push)
#   pragma warning(disable:2196) // warning #2196: routine is both "inline" and "noinline"
#endif

namespace boost { namespace stacktrace {

namespace impl {

#if defined(__GNUC__) && defined(__ELF__)

BOOST_NOINLINE BOOST_SYMBOL_VISIBLE __attribute__((weak))
const char* current_exception_stacktrace() noexcept;

BOOST_NOINLINE BOOST_SYMBOL_VISIBLE __attribute__((weak))
bool& ref_capture_stacktraces_at_throw() noexcept;

#endif

} // namespace impl

/// Class that on construction copies minimal information about call stack into its internals and provides access to that information.
/// @tparam Allocator Allocator to use during stack capture.
template <class Allocator>
class basic_stacktrace {
    std::vector<boost::stacktrace::frame, Allocator> impl_;
    typedef boost::stacktrace::detail::native_frame_ptr_t native_frame_ptr_t;

    /// @cond
    void fill(native_frame_ptr_t* begin, std::size_t size) {
        if (!size) {
            return;
        }

        impl_.reserve(static_cast<std::size_t>(size));
        for (std::size_t i = 0; i < size; ++i) {
            if (!begin[i]) {
                return;
            }
            impl_.push_back(
                frame(begin[i])
            );
        }
    }

    static std::size_t frames_count_from_buffer_size(std::size_t buffer_size) noexcept {
        const std::size_t ret = (buffer_size > sizeof(native_frame_ptr_t) ? buffer_size / sizeof(native_frame_ptr_t) : 0);
        return (ret > 1024 ? 1024 : ret); // Dealing with suspiciously big sizes
    }

    BOOST_NOINLINE void init(std::size_t frames_to_skip, std::size_t max_depth) {
        constexpr std::size_t buffer_size = 128;
        if (!max_depth) {
            return;
        }

        BOOST_TRY {
            {   // Fast path without additional allocations
                native_frame_ptr_t buffer[buffer_size];
                const std::size_t frames_count = boost::stacktrace::detail::this_thread_frames::collect(buffer, buffer_size < max_depth ? buffer_size : max_depth, frames_to_skip + 1);
                if (buffer_size > frames_count || frames_count == max_depth) {
                    fill(buffer, frames_count);
                    return;
                }
            }

            // Failed to fit in `buffer_size`. Allocating memory:
#ifdef BOOST_NO_CXX11_ALLOCATOR
            typedef typename Allocator::template rebind<native_frame_ptr_t>::other allocator_void_t;
#else
            typedef typename std::allocator_traits<Allocator>::template rebind_alloc<native_frame_ptr_t> allocator_void_t;
#endif
            std::vector<native_frame_ptr_t, allocator_void_t> buf(buffer_size * 2, 0, impl_.get_allocator());
            do {
                const std::size_t frames_count = boost::stacktrace::detail::this_thread_frames::collect(&buf[0], buf.size() < max_depth ? buf.size() : max_depth, frames_to_skip + 1);
                if (buf.size() > frames_count || frames_count == max_depth) {
                    fill(&buf[0], frames_count);
                    return;
                }

                buf.resize(buf.size() * 2);
            } while (buf.size() < buf.max_size()); // close to `true`, but suppresses `C4127: conditional expression is constant`.
        } BOOST_CATCH (...) {
            // ignore exception
        }
        BOOST_CATCH_END
    }
    /// @endcond

public:
    typedef typename std::vector<boost::stacktrace::frame, Allocator>::value_type             value_type;
    typedef typename std::vector<boost::stacktrace::frame, Allocator>::allocator_type         allocator_type;
    typedef typename std::vector<boost::stacktrace::frame, Allocator>::const_pointer          pointer;
    typedef typename std::vector<boost::stacktrace::frame, Allocator>::const_pointer          const_pointer;
    typedef typename std::vector<boost::stacktrace::frame, Allocator>::const_reference        reference;
    typedef typename std::vector<boost::stacktrace::frame, Allocator>::const_reference        const_reference;
    typedef typename std::vector<boost::stacktrace::frame, Allocator>::size_type              size_type;
    typedef typename std::vector<boost::stacktrace::frame, Allocator>::difference_type        difference_type;
    typedef typename std::vector<boost::stacktrace::frame, Allocator>::const_iterator         iterator;
    typedef typename std::vector<boost::stacktrace::frame, Allocator>::const_iterator         const_iterator;
    typedef typename std::vector<boost::stacktrace::frame, Allocator>::const_reverse_iterator reverse_iterator;
    typedef typename std::vector<boost::stacktrace::frame, Allocator>::const_reverse_iterator const_reverse_iterator;

    /// @brief Stores the current function call sequence inside *this without any decoding or any other heavy platform specific operations.
    ///
    /// @b Complexity: O(N) where N is call sequence length, O(1) if BOOST_STACKTRACE_USE_NOOP is defined.
    ///
    /// @b Async-Handler-Safety: \asyncsafe if Allocator construction, copying, Allocator::allocate and Allocator::deallocate are async signal safe.
    BOOST_FORCEINLINE basic_stacktrace() noexcept
        : impl_()
    {
        init(0 , static_cast<std::size_t>(-1));
    }

    /// @brief Stores the current function call sequence inside *this without any decoding or any other heavy platform specific operations.
    ///
    /// @b Complexity: O(N) where N is call sequence length, O(1) if BOOST_STACKTRACE_USE_NOOP is defined.
    ///
    /// @b Async-Handler-Safety: \asyncsafe if Allocator construction, copying, Allocator::allocate and Allocator::deallocate are async signal safe.
    ///
    /// @param a Allocator that would be passed to underlying storage.
    BOOST_FORCEINLINE explicit basic_stacktrace(const allocator_type& a) noexcept
        : impl_(a)
    {
        init(0 , static_cast<std::size_t>(-1));
    }

    /// @brief Stores [skip, skip + max_depth) of the current function call sequence inside *this without any decoding or any other heavy platform specific operations.
    ///
    /// @b Complexity: O(N) where N is call sequence length, O(1) if BOOST_STACKTRACE_USE_NOOP is defined.
    ///
    /// @b Async-Handler-Safety: \asyncsafe if Allocator construction, copying, Allocator::allocate and Allocator::deallocate are async signal safe.
    ///
    /// @param skip How many top calls to skip and do not store in *this.
    ///
    /// @param max_depth Max call sequence depth to collect.
    ///
    /// @param a Allocator that would be passed to underlying storage.
    ///
    /// @throws Nothing. Note that default construction of allocator may throw, however it is
    /// performed outside the constructor and exception in `allocator_type()` would not result in calling `std::terminate`.
    BOOST_FORCEINLINE basic_stacktrace(std::size_t skip, std::size_t max_depth, const allocator_type& a = allocator_type()) noexcept
        : impl_(a)
    {
        init(skip , max_depth);
    }

    /// @b Complexity: O(st.size())
    ///
    /// @b Async-Handler-Safety: \asyncsafe if Allocator construction, copying, Allocator::allocate and Allocator::deallocate are async signal safe.
    basic_stacktrace(const basic_stacktrace& st)
        : impl_(st.impl_)
    {}

    /// @b Complexity: O(st.size())
    ///
    /// @b Async-Handler-Safety: \asyncsafe if Allocator construction, copying, Allocator::allocate and Allocator::deallocate are async signal safe.
    basic_stacktrace& operator=(const basic_stacktrace& st) {
        impl_ = st.impl_;
        return *this;
    }

#ifdef BOOST_STACKTRACE_DOXYGEN_INVOKED
    /// @b Complexity: O(1)
    ///
    /// @b Async-Handler-Safety: \asyncsafe if Allocator::deallocate is async signal safe.
    ~basic_stacktrace() noexcept = default;
#endif

#if !defined(BOOST_NO_CXX11_RVALUE_REFERENCES)
    /// @b Complexity: O(1)
    ///
    /// @b Async-Handler-Safety: \asyncsafe if Allocator construction and copying are async signal safe.
    basic_stacktrace(basic_stacktrace&& st) noexcept
        : impl_(std::move(st.impl_))
    {}

    /// @b Complexity: O(st.size())
    ///
    /// @b Async-Handler-Safety: \asyncsafe if Allocator construction and copying are async signal safe.
    basic_stacktrace& operator=(basic_stacktrace&& st)
#ifndef BOOST_NO_CXX11_HDR_TYPE_TRAITS
        noexcept(( std::is_nothrow_move_assignable< std::vector<boost::stacktrace::frame, Allocator> >::value ))
#else
        noexcept
#endif
    {
        impl_ = std::move(st.impl_);
        return *this;
    }
#endif

    /// @returns Number of function names stored inside the class.
    ///
    /// @b Complexity: O(1)
    ///
    /// @b Async-Handler-Safety: \asyncsafe.
    size_type size() const noexcept {
        return impl_.size();
    }

    /// @param frame_no Zero based index of frame to return. 0
    /// is the function index where stacktrace was constructed and
    /// index close to this->size() contains function `main()`.
    /// @returns frame that references the actual frame info, stored inside *this.
    ///
    /// @b Complexity: O(1).
    ///
    /// @b Async-Handler-Safety: \asyncsafe.
    const_reference operator[](std::size_t frame_no) const noexcept {
        return impl_[frame_no];
    }

    /// @b Complexity: O(1)
    ///
    /// @b Async-Handler-Safety: \asyncsafe.
    const_iterator begin() const noexcept { return impl_.begin(); }
    /// @b Complexity: O(1)
    ///
    /// @b Async-Handler-Safety: \asyncsafe.
    const_iterator cbegin() const noexcept { return impl_.begin(); }
    /// @b Complexity: O(1)
    ///
    /// @b Async-Handler-Safety: \asyncsafe.
    const_iterator end() const noexcept { return impl_.end(); }
    /// @b Complexity: O(1)
    ///
    /// @b Async-Handler-Safety: \asyncsafe.
    const_iterator cend() const noexcept { return impl_.end(); }

    /// @b Complexity: O(1)
    ///
    /// @b Async-Handler-Safety: \asyncsafe.
    const_reverse_iterator rbegin() const noexcept { return impl_.rbegin(); }
    /// @b Complexity: O(1)
    ///
    /// @b Async-Handler-Safety: \asyncsafe.
    const_reverse_iterator crbegin() const noexcept { return impl_.rbegin(); }
    /// @b Complexity: O(1)
    ///
    /// @b Async-Handler-Safety: \asyncsafe.
    const_reverse_iterator rend() const noexcept { return impl_.rend(); }
    /// @b Complexity: O(1)
    ///
    /// @b Async-Handler-Safety: \asyncsafe.
    const_reverse_iterator crend() const noexcept { return impl_.rend(); }


    /// @brief Allows to check that stack trace capturing was successful.
    /// @returns `true` if `this->size() != 0`
    ///
    /// @b Complexity: O(1)
    ///
    /// @b Async-Handler-Safety: \asyncsafe.
    constexpr explicit operator bool () const noexcept { return !empty(); }

    /// @brief Allows to check that stack trace failed.
    /// @returns `true` if `this->size() == 0`
    ///
    /// @b Complexity: O(1)
    ///
    /// @b Async-Handler-Safety: \asyncsafe.
    bool empty() const noexcept { return !size(); }

    const std::vector<boost::stacktrace::frame, Allocator>& as_vector() const noexcept {
        return impl_;
    }

    /// Constructs stacktrace from basic_istreamable that references the dumped stacktrace. Terminating zero frame is discarded.
    ///
    /// @b Complexity: O(N)
    template <class Char, class Trait>
    static basic_stacktrace from_dump(std::basic_istream<Char, Trait>& in, const allocator_type& a = allocator_type()) {
        typedef typename std::basic_istream<Char, Trait>::pos_type pos_type;
        basic_stacktrace ret(0, 0, a);

        // reserving space
        const pos_type pos = in.tellg();
        in.seekg(0, in.end);
        const std::size_t frames_count = frames_count_from_buffer_size(static_cast<std::size_t>(in.tellg()));
        in.seekg(pos);
        
        if (!frames_count) {
            return ret;
        }

        native_frame_ptr_t ptr = 0;
        ret.impl_.reserve(frames_count);
        while (in.read(reinterpret_cast<Char*>(&ptr), sizeof(ptr))) {
            if (!ptr) {
                break;
            }

            ret.impl_.push_back(frame(ptr));
        }

        return ret;
    }

    /// Constructs stacktrace from raw memory dump. Terminating zero frame is discarded.
    ///
    /// @param begin Beginning of the memory where the stacktrace was saved using the boost::stacktrace::safe_dump_to
    ///
    /// @param buffer_size_in_bytes Size of the memory. Usually the same value that was passed to the boost::stacktrace::safe_dump_to
    ///
    /// @b Complexity: O(size) in worst case
    static basic_stacktrace from_dump(const void* begin, std::size_t buffer_size_in_bytes, const allocator_type& a = allocator_type()) {
        basic_stacktrace ret(0, 0, a);
        const native_frame_ptr_t* first = static_cast<const native_frame_ptr_t*>(begin);
        const std::size_t frames_count = frames_count_from_buffer_size(buffer_size_in_bytes);
        if (!frames_count) {
            return ret;
        }

        const native_frame_ptr_t* const last = first + frames_count;
        ret.impl_.reserve(frames_count);
        for (; first != last; ++first) {
            if (!*first) {
                break;
            }

            ret.impl_.push_back(frame(*first));
        }

        return ret;
    }

    /// Returns a basic_stacktrace object containing a stacktrace captured at
    /// the point where the currently handled exception was thrown by its
    /// initial throw-expression (i.e. not a rethrow), or an empty
    /// basic_stacktrace object if:
    ///
    /// - the `boost_stacktrace_from_exception` library is not linked to the
    ///   current binary, or
    /// - the initialization of stacktrace failed, or
    /// - stacktrace captures are not enabled for the throwing thread, or
    /// - no exception is being handled, or
    /// - due to implementation-defined reasons.
    ///
    /// `alloc` is passed to the constructor of the stacktrace object.
    /// Rethrowing an exception using a throw-expression with no operand does
    /// not alter the captured stacktrace.
    ///
    /// Implements https://wg21.link/p2370r1
    static basic_stacktrace<Allocator> from_current_exception(const allocator_type& alloc = allocator_type()) noexcept {
        // Matches the constant from implementation
        constexpr std::size_t kStacktraceDumpSize = 4096;

        const char* trace = nullptr;
#if defined(__GNUC__) && defined(__ELF__)
        if (impl::current_exception_stacktrace) {
            trace = impl::current_exception_stacktrace();
        }
#endif

        if (trace) {
            try {
                return basic_stacktrace<Allocator>::from_dump(trace, kStacktraceDumpSize, alloc);
            } catch (const std::exception&) {
                // ignore
            }
        }
        return basic_stacktrace<Allocator>{0, 0, alloc};
    }
};

/// @brief Compares stacktraces for less, order is platform dependent.
///
/// @b Complexity: Amortized O(1); worst case O(size())
///
/// @b Async-Handler-Safety: \asyncsafe.
template <class Allocator1, class Allocator2>
bool operator< (const basic_stacktrace<Allocator1>& lhs, const basic_stacktrace<Allocator2>& rhs) noexcept {
    return lhs.size() < rhs.size() || (lhs.size() == rhs.size() && lhs.as_vector() < rhs.as_vector());
}

/// @brief Compares stacktraces for equality.
///
/// @b Complexity: Amortized O(1); worst case O(size())
///
/// @b Async-Handler-Safety: \asyncsafe.
template <class Allocator1, class Allocator2>
bool operator==(const basic_stacktrace<Allocator1>& lhs, const basic_stacktrace<Allocator2>& rhs) noexcept {
    return lhs.as_vector() == rhs.as_vector();
}


/// Comparison operators that provide platform dependant ordering and have amortized O(1) complexity; O(size()) worst case complexity; are Async-Handler-Safe.
template <class Allocator1, class Allocator2>
bool operator> (const basic_stacktrace<Allocator1>& lhs, const basic_stacktrace<Allocator2>& rhs) noexcept {
    return rhs < lhs;
}

template <class Allocator1, class Allocator2>
bool operator<=(const basic_stacktrace<Allocator1>& lhs, const basic_stacktrace<Allocator2>& rhs) noexcept {
    return !(lhs > rhs);
}

template <class Allocator1, class Allocator2>
bool operator>=(const basic_stacktrace<Allocator1>& lhs, const basic_stacktrace<Allocator2>& rhs) noexcept {
    return !(lhs < rhs);
}

template <class Allocator1, class Allocator2>
bool operator!=(const basic_stacktrace<Allocator1>& lhs, const basic_stacktrace<Allocator2>& rhs) noexcept {
    return !(lhs == rhs);
}

/// Fast hashing support, O(st.size()) complexity; Async-Handler-Safe.
template <class Allocator>
std::size_t hash_value(const basic_stacktrace<Allocator>& st) noexcept {
    return boost::hash_range(st.as_vector().begin(), st.as_vector().end());
}

/// Returns std::string with the stacktrace in a human readable format; unsafe to use in async handlers.
template <class Allocator>
std::string to_string(const basic_stacktrace<Allocator>& bt) {
    if (!bt) {
        return std::string();
    }

    return boost::stacktrace::detail::to_string(&bt.as_vector()[0], bt.size());
}

/// Outputs stacktrace in a human readable format to the output stream `os`; unsafe to use in async handlers.
template <class CharT, class TraitsT, class Allocator>
std::basic_ostream<CharT, TraitsT>& operator<<(std::basic_ostream<CharT, TraitsT>& os, const basic_stacktrace<Allocator>& bt) {
    return os << boost::stacktrace::to_string(bt);
}

/// This is the typedef to use unless you'd like to provide a specific allocator to boost::stacktrace::basic_stacktrace.
typedef basic_stacktrace<> stacktrace;

}} // namespace boost::stacktrace

#ifdef BOOST_INTEL
#   pragma warning(pop)
#endif

#endif // BOOST_STACKTRACE_STACKTRACE_HPP