Abseil Common Libraries (C++) (grcp 依赖)
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81 lines
2.0 KiB
81 lines
2.0 KiB
// Copyright 2019 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/scoped_set_env.h" |
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#ifdef _WIN32 |
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#include <windows.h> |
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#endif |
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#include <cstdlib> |
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#include "absl/base/internal/raw_logging.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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#ifdef _WIN32 |
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const int kMaxEnvVarValueSize = 1024; |
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#endif |
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void SetEnvVar(const char* name, const char* value) { |
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#ifdef _WIN32 |
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SetEnvironmentVariableA(name, value); |
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#else |
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if (value == nullptr) { |
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::unsetenv(name); |
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} else { |
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::setenv(name, value, 1); |
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} |
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#endif |
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} |
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} // namespace |
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ScopedSetEnv::ScopedSetEnv(const char* var_name, const char* new_value) |
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: var_name_(var_name), was_unset_(false) { |
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#ifdef _WIN32 |
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char buf[kMaxEnvVarValueSize]; |
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auto get_res = GetEnvironmentVariableA(var_name_.c_str(), buf, sizeof(buf)); |
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ABSL_INTERNAL_CHECK(get_res < sizeof(buf), "value exceeds buffer size"); |
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if (get_res == 0) { |
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was_unset_ = (GetLastError() == ERROR_ENVVAR_NOT_FOUND); |
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} else { |
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old_value_.assign(buf, get_res); |
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} |
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SetEnvironmentVariableA(var_name_.c_str(), new_value); |
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#else |
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const char* val = ::getenv(var_name_.c_str()); |
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if (val == nullptr) { |
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was_unset_ = true; |
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} else { |
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old_value_ = val; |
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} |
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#endif |
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SetEnvVar(var_name_.c_str(), new_value); |
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} |
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ScopedSetEnv::~ScopedSetEnv() { |
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SetEnvVar(var_name_.c_str(), was_unset_ ? nullptr : old_value_.c_str()); |
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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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