| /* |
| * |
| * Copyright 2017 gRPC authors. |
| * |
| * Licensed under the Apache License, Version 2.0 (the "License"); |
| * you may not use this file except in compliance with the License. |
| * You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| * |
| */ |
| |
| #ifndef GRPC_CORE_LIB_IOMGR_LOCKFREE_EVENT_H |
| #define GRPC_CORE_LIB_IOMGR_LOCKFREE_EVENT_H |
| |
| /* Lock free event notification for file descriptors */ |
| |
| #include <grpc/support/port_platform.h> |
| |
| #include <grpc/support/atm.h> |
| |
| #include "src/core/lib/iomgr/closure.h" |
| |
| namespace grpc_core { |
| |
| class LockfreeEvent { |
| public: |
| LockfreeEvent(); |
| |
| LockfreeEvent(const LockfreeEvent&) = delete; |
| LockfreeEvent& operator=(const LockfreeEvent&) = delete; |
| |
| // These methods are used to initialize and destroy the internal state. These |
| // cannot be done in constructor and destructor because SetReady may be called |
| // when the event is destroyed and put in a freelist. |
| void InitEvent(); |
| void DestroyEvent(); |
| |
| // Returns true if fd has been shutdown, false otherwise. |
| bool IsShutdown() const { |
| return (gpr_atm_no_barrier_load(&state_) & kShutdownBit) != 0; |
| } |
| |
| // Schedules \a closure when the event is received (see SetReady()) or the |
| // shutdown state has been set. Note that the event may have already been |
| // received, in which case the closure would be scheduled immediately. |
| // If the shutdown state has already been set, then \a closure is scheduled |
| // with the shutdown error. |
| void NotifyOn(grpc_closure* closure); |
| |
| // Sets the shutdown state. If a closure had been provided by NotifyOn and has |
| // not yet been scheduled, it will be scheduled with \a error. |
| bool SetShutdown(grpc_error* error); |
| |
| // Signals that the event has been received. |
| void SetReady(); |
| |
| private: |
| enum State { kClosureNotReady = 0, kClosureReady = 2, kShutdownBit = 1 }; |
| |
| gpr_atm state_; |
| }; |
| |
| } // namespace grpc_core |
| |
| #endif /* GRPC_CORE_LIB_IOMGR_LOCKFREE_EVENT_H */ |