backtrace.h

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#pragma once

#include <cstdint>

#include "stx/internal/option_result.h"
#include "stx/report.h"


STX_BEGIN_NAMESPACE

namespace backtrace {

enum class SignalError {
  Unknown,
  SigErr
};

inline SpanReport operator>>(ReportQuery, SignalError const &err) noexcept {
  switch (err) {
    case SignalError::Unknown:
      return SpanReport(
          "Uknown signal given, 'handle_signal' can only handle 'SIGSEGV', "
          "'SIGILL' and 'SIGFPE'.");
    case SignalError::SigErr:
      return SpanReport("'std::signal' returned 'SIGERR'");
  }
}

struct CharSpan {
  char *data;
  size_t size;
  CharSpan(char *data_, size_t size_) noexcept : data{data_}, size{size_} {}
  CharSpan(CharSpan const &) noexcept = default;
  CharSpan(CharSpan &&) noexcept = default;
  CharSpan &operator=(CharSpan const &) noexcept = default;
  CharSpan &operator=(CharSpan &&) noexcept = default;
  ~CharSpan() noexcept = default;
};

struct Symbol {
  auto raw() const noexcept -> std::string_view;

  explicit Symbol(CharSpan sym) noexcept : symbol_{sym} {};

 private:
  CharSpan symbol_;
};

struct Frame {
  Option<uintptr_t> ip;
  Option<uintptr_t> sp;
  Option<uintptr_t> offset;
  Option<Symbol> symbol;

  constexpr explicit Frame() = default;
  Frame(Frame &&) = default;
  Frame &operator=(Frame &&) = default;
  Frame(Frame const &) = default;
  Frame &operator=(Frame const &) = default;
  ~Frame() = default;
};

using Callback = bool (*)(Frame, int);

// all memory passed to the callback is cleared after each call. Hence we only
// use one stack memory for the callback feed-loop.
int trace(Callback callback, int skip_count = 0);

auto handle_signal(int signal) noexcept -> Result<void (*)(int), SignalError>;

}  // namespace backtrace

STX_END_NAMESPACE