1//
2// Copyright 2019 The Abseil Authors.
3//
4// Licensed under the Apache License, Version 2.0 (the "License");
5// you may not use this file except in compliance with the License.
6// You may obtain a copy of the License at
7//
8// https://www.apache.org/licenses/LICENSE-2.0
9//
10// Unless required by applicable law or agreed to in writing, software
11// distributed under the License is distributed on an "AS IS" BASIS,
12// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13// See the License for the specific language governing permissions and
14// limitations under the License.
15
16#include "absl/flags/flag.h"
17
18#include <cstring>
19
20namespace absl {
21
22// We want to validate the type mismatch between type definition and
23// declaration. The lock-free implementation does not allow us to do it,
24// so in debug builds we always use the slower implementation, which always
25// validates the type.
26#ifndef NDEBUG
27#define ABSL_FLAGS_ATOMIC_GET(T) \
28 T GetFlag(const absl::Flag<T>& flag) { \
29 T result; \
30 flag.internal.Read(&result, &flags_internal::FlagOps<T>); \
31 return result; \
32 }
33#else
34#define ABSL_FLAGS_ATOMIC_GET(T) \
35 T GetFlag(const absl::Flag<T>& flag) { \
36 const int64_t r = flag.internal.atomic.load(std::memory_order_acquire); \
37 if (r != flags_internal::CommandLineFlag::kAtomicInit) { \
38 T t; \
39 memcpy(&t, &r, sizeof(T)); \
40 return t; \
41 } \
42 T result; \
43 flag.internal.Read(&result, &flags_internal::FlagOps<T>); \
44 return result; \
45 }
46#endif
47
48ABSL_FLAGS_INTERNAL_FOR_EACH_LOCK_FREE(ABSL_FLAGS_ATOMIC_GET)
49
50#undef ABSL_FLAGS_ATOMIC_GET
51
52} // namespace absl
53