Abseil Common Libraries (C++) (grcp 依赖)
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60 lines
1.8 KiB
60 lines
1.8 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/flag.h" |
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#include <cstring> |
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namespace absl { |
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// We want to validate the type mismatch between type definition and |
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// declaration. The lock-free implementation does not allow us to do it, |
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// so in debug builds we always use the slower implementation, which always |
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// validates the type. |
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#ifndef NDEBUG |
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#define ABSL_FLAGS_ATOMIC_GET(T) \ |
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T GetFlag(const absl::Flag<T>& flag) { return flag.Get(); } |
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#else |
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#define ABSL_FLAGS_ATOMIC_GET(T) \ |
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T GetFlag(const absl::Flag<T>& flag) { \ |
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T result; \ |
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if (flag.AtomicGet(&result)) { \ |
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return result; \ |
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} \ |
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return flag.Get(); \ |
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} |
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#endif |
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ABSL_FLAGS_INTERNAL_FOR_EACH_LOCK_FREE(ABSL_FLAGS_ATOMIC_GET) |
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#undef ABSL_FLAGS_ATOMIC_GET |
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// This global nutex protects on-demand construction of flag objects in MSVC |
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// builds. |
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#if defined(_MSC_VER) |
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namespace flags_internal { |
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ABSL_CONST_INIT static absl::Mutex construction_guard(absl::kConstInit); |
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void LockGlobalConstructionGuard() { construction_guard.Lock(); } |
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void UnlockGlobalConstructionGuard() { construction_guard.Unlock(); } |
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} // namespace flags_internal |
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#endif |
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} // namespace absl
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