tvl-depot/absl/base/internal/strerror.cc
Abseil Team 2d2a8aea29 Export of internal Abseil changes
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a85860e450815776c8753f34348f41ab0e918d36 by Gennadiy Rozental <rogeeff@google.com>:

Rename ComamndLineFlag's interface SetFromString as ParseFrom.

This is the name approved by C++ API review.

PiperOrigin-RevId: 301543521

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28f31bae2a136854fd89f0a32f281d12a40f702c by Abseil Team <absl-team@google.com>:

Internal change

PiperOrigin-RevId: 301524919

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a68da3d6fbbca4c5f41a20e99ed72bb1c5dd1165 by Abseil Team <absl-team@google.com>:

Introduce absl::base_internal::StrError, a portability wrapper around the various thread-safe alternatives to C89's strerror.

PiperOrigin-RevId: 301513962

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92ccac3b6eb18cb41cddedbfdab53b9ad481505d by Andy Getzendanner <durandal@google.com>:

Introduce absl::base_internal::StrError, a portability wrapper around the various thread-safe alternatives to C89's strerror.

PiperOrigin-RevId: 301493389

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8e196def47c250941202840d6a1de686d681cd3e by Abseil Team <absl-team@google.com>:

Internal change

PiperOrigin-RevId: 301363394

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dd1dcffa6c47675ba4d198730a301bd408142298 by Gennadiy Rozental <rogeeff@google.com>:

Add validation for size of void* to match the size of free function pointer.

PiperOrigin-RevId: 301341331
GitOrigin-RevId: a85860e450815776c8753f34348f41ab0e918d36
Change-Id: I27c9d1365d3c9b4328d1587ab3ac38e2d09a6ec2
2020-03-18 17:29:54 -04:00

75 lines
2.2 KiB
C++

// Copyright 2020 The Abseil Authors.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// https://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
#include "absl/base/internal/strerror.h"
#include <cerrno>
#include <cstddef>
#include <cstdio>
#include <cstring>
#include <string>
#include <type_traits>
#include "absl/base/attributes.h"
#include "absl/base/internal/errno_saver.h"
namespace absl {
ABSL_NAMESPACE_BEGIN
namespace base_internal {
namespace {
const char* StrErrorAdaptor(int errnum, char* buf, size_t buflen) {
#if defined(_WIN32)
int rc = strerror_s(buf, buflen, errnum);
buf[buflen - 1] = '\0'; // guarantee NUL termination
if (rc == 0 && strncmp(buf, "Unknown error", buflen) == 0) *buf = '\0';
return buf;
#else
#if defined(__GLIBC__) || defined(__APPLE__)
// Use the BSD sys_errlist API provided by GNU glibc and others to
// avoid any need to copy the message into the local buffer first.
if (0 <= errnum && errnum < sys_nerr) {
if (const char* p = sys_errlist[errnum]) {
return p;
}
}
#endif
// The type of `ret` is platform-specific; both of these branches must compile
// either way but only one will execute on any given platform:
auto ret = strerror_r(errnum, buf, buflen);
if (std::is_same<decltype(ret), int>::value) {
// XSI `strerror_r`; `ret` is `int`:
if (ret) *buf = '\0';
return buf;
} else {
// GNU `strerror_r`; `ret` is `char *`:
return reinterpret_cast<const char*>(ret);
}
#endif
}
} // namespace
std::string StrError(int errnum) {
absl::base_internal::ErrnoSaver errno_saver;
char buf[100];
const char* str = StrErrorAdaptor(errnum, buf, sizeof buf);
if (*str == '\0') {
snprintf(buf, sizeof buf, "Unknown error %d", errnum);
str = buf;
}
return str;
}
} // namespace base_internal
ABSL_NAMESPACE_END
} // namespace absl