xref: /aosp_15_r20/external/abseil-cpp/absl/synchronization/internal/stdcpp_waiter.h (revision 9356374a3709195abf420251b3e825997ff56c0f)
1 // Copyright 2023 The Abseil Authors.
2 //
3 // Licensed under the Apache License, Version 2.0 (the "License");
4 // you may not use this file except in compliance with the License.
5 // You may obtain a copy of the License at
6 //
7 //      https://www.apache.org/licenses/LICENSE-2.0
8 //
9 // Unless required by applicable law or agreed to in writing, software
10 // distributed under the License is distributed on an "AS IS" BASIS,
11 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12 // See the License for the specific language governing permissions and
13 // limitations under the License.
14 //
15 
16 #ifndef ABSL_SYNCHRONIZATION_INTERNAL_STDCPP_WAITER_H_
17 #define ABSL_SYNCHRONIZATION_INTERNAL_STDCPP_WAITER_H_
18 
19 #include <condition_variable>  // NOLINT(build/c++11)
20 #include <mutex>  // NOLINT(build/c++11)
21 
22 #include "absl/base/config.h"
23 #include "absl/synchronization/internal/kernel_timeout.h"
24 #include "absl/synchronization/internal/waiter_base.h"
25 
26 namespace absl {
27 ABSL_NAMESPACE_BEGIN
28 namespace synchronization_internal {
29 
30 #define ABSL_INTERNAL_HAVE_STDCPP_WAITER 1
31 
32 class StdcppWaiter : public WaiterCrtp<StdcppWaiter> {
33  public:
34   StdcppWaiter();
35 
36   bool Wait(KernelTimeout t);
37   void Post();
38   void Poke();
39 
40   static constexpr char kName[] = "StdcppWaiter";
41 
42  private:
43   // REQUIRES: mu_ must be held.
44   void InternalCondVarPoke();
45 
46   std::mutex mu_;
47   std::condition_variable cv_;
48   int waiter_count_;
49   int wakeup_count_;  // Unclaimed wakeups.
50 };
51 
52 }  // namespace synchronization_internal
53 ABSL_NAMESPACE_END
54 }  // namespace absl
55 
56 #endif  // ABSL_SYNCHRONIZATION_INTERNAL_STDCPP_WAITER_H_
57