Built motion from commit 6a09e18b.|2.6.11

[motion2.git] / legacy-libs / grpc-cloned / deps / grpc / src / core / lib / iomgr / lockfree_event.h

diff --git a/legacy-libs/grpc-cloned/deps/grpc/src/core/lib/iomgr/lockfree_event.h b/legacy-libs/grpc-cloned/deps/grpc/src/core/lib/iomgr/lockfree_event.h
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+/*
+ *
+ * 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 */