libcxx/src/system_error.cpp

//===---------------------- system_error.cpp ------------------------------===//
//
//                     The LLVM Compiler Infrastructure
//
// This file is dual licensed under the MIT and the University of Illinois Open
// Source Licenses. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//

#include "__config"

#define _LIBCPP_BUILDING_SYSTEM_ERROR
#include "system_error"

#include "include/config_elast.h"
#include "cerrno"
#include "cstring"
#include "cstdio"
#include "cstdlib"
#include "cassert"
#include "string"
#include "string.h"

_LIBCPP_BEGIN_NAMESPACE_STD

// class error_category

error_category::error_category() _NOEXCEPT
{
}

error_category::~error_category() _NOEXCEPT
{
}

error_condition
error_category::default_error_condition(int ev) const _NOEXCEPT
{
    return error_condition(ev, *this);
}

bool
error_category::equivalent(int code, const error_condition& condition) const _NOEXCEPT
{
    return default_error_condition(code) == condition;
}

bool
error_category::equivalent(const error_code& code, int condition) const _NOEXCEPT
{
    return *this == code.category() && code.value() == condition;
}

namespace {

//  GLIBC also uses 1024 as the maximum buffer size internally.
constexpr size_t strerror_buff_size = 1024;

string do_strerror_r(int ev);

#if defined(__linux__) && !defined(_LIBCPP_HAS_MUSL_LIBC)
// GNU Extended version
string do_strerror_r(int ev) {
    char buffer[strerror_buff_size];
    char* ret = ::strerror_r(ev, buffer, strerror_buff_size);
    return string(ret);
}
#else
// POSIX version
string do_strerror_r(int ev) {
    char buffer[strerror_buff_size];
    const int old_errno = errno;
    int ret;
    if ((ret = ::strerror_r(ev, buffer, strerror_buff_size)) != 0) {
        // If `ret == -1` then the error is specified using `errno`, otherwise
        // `ret` represents the error.
        const int new_errno = ret == -1 ? errno : ret;
        errno = old_errno;
        if (new_errno == EINVAL) {
            std::snprintf(buffer, strerror_buff_size, "Unknown error %d", ev);
            return string(buffer);
        } else {
            assert(new_errno == ERANGE);
            // FIXME maybe? 'strerror_buff_size' is likely to exceed the
            // maximum error size so ERANGE shouldn't be returned.
            std::abort();
        }
    }
    return string(buffer);
}
#endif

} // end namespace

string
__do_message::message(int ev) const
{
#if defined(_LIBCPP_HAS_NO_THREADS)
    return string(::strerror(ev));
#else
    return do_strerror_r(ev);
#endif
}

class _LIBCPP_HIDDEN __generic_error_category
    : public __do_message
{
public:
    virtual const char* name() const _NOEXCEPT;
    virtual string message(int ev) const;
};

const char*
__generic_error_category::name() const _NOEXCEPT
{
    return "generic";
}

string
__generic_error_category::message(int ev) const
{
#ifdef _LIBCPP_ELAST
    if (ev > _LIBCPP_ELAST)
      return string("unspecified generic_category error");
#endif  // _LIBCPP_ELAST
    return __do_message::message(ev);
}

const error_category&
generic_category() _NOEXCEPT
{
    static __generic_error_category s;
    return s;
}

class _LIBCPP_HIDDEN __system_error_category
    : public __do_message
{
public:
    virtual const char* name() const _NOEXCEPT;
    virtual string message(int ev) const;
    virtual error_condition default_error_condition(int ev) const _NOEXCEPT;
};

const char*
__system_error_category::name() const _NOEXCEPT
{
    return "system";
}

string
__system_error_category::message(int ev) const
{
#ifdef _LIBCPP_ELAST
    if (ev > _LIBCPP_ELAST)
      return string("unspecified system_category error");
#endif  // _LIBCPP_ELAST
    return __do_message::message(ev);
}

error_condition
__system_error_category::default_error_condition(int ev) const _NOEXCEPT
{
#ifdef _LIBCPP_ELAST
    if (ev > _LIBCPP_ELAST)
      return error_condition(ev, system_category());
#endif  // _LIBCPP_ELAST
    return error_condition(ev, generic_category());
}

const error_category&
system_category() _NOEXCEPT
{
    static __system_error_category s;
    return s;
}

// error_condition

string
error_condition::message() const
{
    return __cat_->message(__val_);
}

// error_code

string
error_code::message() const
{
    return __cat_->message(__val_);
}

// system_error

string
system_error::__init(const error_code& ec, string what_arg)
{
    if (ec)
    {
        if (!what_arg.empty())
            what_arg += ": ";
        what_arg += ec.message();
    }
    return what_arg;
}

system_error::system_error(error_code ec, const string& what_arg)
    : runtime_error(__init(ec, what_arg)),
      __ec_(ec)
{
}

system_error::system_error(error_code ec, const char* what_arg)
    : runtime_error(__init(ec, what_arg)),
      __ec_(ec)
{
}

system_error::system_error(error_code ec)
    : runtime_error(__init(ec, "")),
      __ec_(ec)
{
}

system_error::system_error(int ev, const error_category& ecat, const string& what_arg)
    : runtime_error(__init(error_code(ev, ecat), what_arg)),
      __ec_(error_code(ev, ecat))
{
}

system_error::system_error(int ev, const error_category& ecat, const char* what_arg)
    : runtime_error(__init(error_code(ev, ecat), what_arg)),
      __ec_(error_code(ev, ecat))
{
}

system_error::system_error(int ev, const error_category& ecat)
    : runtime_error(__init(error_code(ev, ecat), "")),
      __ec_(error_code(ev, ecat))
{
}

system_error::~system_error() _NOEXCEPT
{
}

void
__throw_system_error(int ev, const char* what_arg)
{
#ifndef _LIBCPP_NO_EXCEPTIONS
    throw system_error(error_code(ev, system_category()), what_arg);
#else
    (void)ev;
    (void)what_arg;
#endif
}

_LIBCPP_END_NAMESPACE_STD