Abseil Common Libraries (C++) (grcp 依赖)
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88 lines
2.6 KiB
88 lines
2.6 KiB
// Copyright 2020 The Abseil Authors. |
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// |
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// Licensed under the Apache License, Version 2.0 (the "License"); |
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// you may not use this file except in compliance with the License. |
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// You may obtain a copy of the License at |
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// |
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// https://www.apache.org/licenses/LICENSE-2.0 |
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// |
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// Unless required by applicable law or agreed to in writing, software |
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// distributed under the License is distributed on an "AS IS" BASIS, |
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
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// See the License for the specific language governing permissions and |
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// limitations under the License. |
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#include "absl/base/internal/strerror.h" |
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#include <array> |
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#include <cerrno> |
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#include <cstddef> |
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#include <cstdio> |
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#include <cstring> |
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#include <string> |
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#include <type_traits> |
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#include "absl/base/internal/errno_saver.h" |
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namespace absl { |
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ABSL_NAMESPACE_BEGIN |
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namespace base_internal { |
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namespace { |
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const char* StrErrorAdaptor(int errnum, char* buf, size_t buflen) { |
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#if defined(_WIN32) |
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int rc = strerror_s(buf, buflen, errnum); |
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buf[buflen - 1] = '\0'; // guarantee NUL termination |
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if (rc == 0 && strncmp(buf, "Unknown error", buflen) == 0) *buf = '\0'; |
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return buf; |
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#else |
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// The type of `ret` is platform-specific; both of these branches must compile |
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// either way but only one will execute on any given platform: |
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auto ret = strerror_r(errnum, buf, buflen); |
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if (std::is_same<decltype(ret), int>::value) { |
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// XSI `strerror_r`; `ret` is `int`: |
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if (ret) *buf = '\0'; |
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return buf; |
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} else { |
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// GNU `strerror_r`; `ret` is `char *`: |
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return reinterpret_cast<const char*>(ret); |
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} |
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#endif |
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} |
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std::string StrErrorInternal(int errnum) { |
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char buf[100]; |
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const char* str = StrErrorAdaptor(errnum, buf, sizeof buf); |
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if (*str == '\0') { |
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snprintf(buf, sizeof buf, "Unknown error %d", errnum); |
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str = buf; |
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} |
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return str; |
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} |
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// kSysNerr is the number of errors from a recent glibc. `StrError()` falls back |
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// to `StrErrorAdaptor()` if the value is larger than this. |
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constexpr int kSysNerr = 135; |
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std::array<std::string, kSysNerr>* NewStrErrorTable() { |
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auto* table = new std::array<std::string, kSysNerr>; |
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for (int i = 0; i < static_cast<int>(table->size()); ++i) { |
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(*table)[i] = StrErrorInternal(i); |
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} |
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return table; |
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} |
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} // namespace |
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std::string StrError(int errnum) { |
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absl::base_internal::ErrnoSaver errno_saver; |
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static const auto* table = NewStrErrorTable(); |
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if (errnum >= 0 && errnum < static_cast<int>(table->size())) { |
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return (*table)[errnum]; |
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} |
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return StrErrorInternal(errnum); |
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} |
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} // namespace base_internal |
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ABSL_NAMESPACE_END |
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} // namespace absl
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