Abseil Common Libraries (C++) (grcp 依赖)
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53 lines
2.2 KiB
53 lines
2.2 KiB
6 years ago
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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) { \
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T result; \
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flag.internal.Read(&result, &flags_internal::FlagOps<T>); \
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return result; \
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}
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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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const int64_t r = flag.internal.atomic.load(std::memory_order_acquire); \
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if (r != flags_internal::CommandLineFlag::kAtomicInit) { \
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T t; \
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memcpy(&t, &r, sizeof(T)); \
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return t; \
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} \
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T result; \
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flag.internal.Read(&result, &flags_internal::FlagOps<T>); \
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return result; \
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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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} // namespace absl
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