Abseil Common Libraries (C++) (grcp 依赖)
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65 lines
2.3 KiB
65 lines
2.3 KiB
// |
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// 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/flags/usage.h" |
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#include <stdlib.h> |
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#include <string> |
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#include "absl/base/attributes.h" |
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#include "absl/base/config.h" |
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#include "absl/base/const_init.h" |
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#include "absl/base/thread_annotations.h" |
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#include "absl/flags/internal/usage.h" |
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#include "absl/strings/string_view.h" |
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#include "absl/synchronization/mutex.h" |
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namespace absl { |
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ABSL_NAMESPACE_BEGIN |
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namespace flags_internal { |
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namespace { |
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ABSL_CONST_INIT absl::Mutex usage_message_guard(absl::kConstInit); |
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ABSL_CONST_INIT std::string* program_usage_message |
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ABSL_GUARDED_BY(usage_message_guard) = nullptr; |
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} // namespace |
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} // namespace flags_internal |
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// -------------------------------------------------------------------- |
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// Sets the "usage" message to be used by help reporting routines. |
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void SetProgramUsageMessage(absl::string_view new_usage_message) { |
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absl::MutexLock l(&flags_internal::usage_message_guard); |
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if (flags_internal::program_usage_message != nullptr) { |
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ABSL_INTERNAL_LOG(FATAL, "SetProgramUsageMessage() called twice."); |
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std::exit(1); |
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} |
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flags_internal::program_usage_message = new std::string(new_usage_message); |
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} |
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// -------------------------------------------------------------------- |
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// Returns the usage message set by SetProgramUsageMessage(). |
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// Note: We able to return string_view here only because calling |
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// SetProgramUsageMessage twice is prohibited. |
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absl::string_view ProgramUsageMessage() { |
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absl::MutexLock l(&flags_internal::usage_message_guard); |
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return flags_internal::program_usage_message != nullptr |
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? absl::string_view(*flags_internal::program_usage_message) |
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: "Warning: SetProgramUsageMessage() never called"; |
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} |
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ABSL_NAMESPACE_END |
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} // namespace absl
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