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Pods/gRPC-C++/include/grpcpp/impl/sync.h

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+//
+//
+// Copyright 2019 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 GRPCPP_IMPL_SYNC_H
+#define GRPCPP_IMPL_SYNC_H
+
+#include <grpc/support/port_platform.h>
+
+#ifdef GPR_HAS_PTHREAD_H
+#include <pthread.h>
+#endif
+
+#include <mutex>
+
+#include "absl/synchronization/mutex.h"
+
+#include <grpc/support/log.h>
+#include <grpc/support/sync.h>
+#include <grpc/support/time.h>
+
+// The core library is not accessible in C++ codegen headers, and vice versa.
+// Thus, we need to have duplicate headers with similar functionality.
+// Make sure any change to this file is also reflected in
+// src/core/lib/gprpp/sync.h too.
+//
+// Whenever possible, prefer "src/core/lib/gprpp/sync.h" over this file,
+// since in core we do not rely on g_core_codegen_interface and hence do not
+// pay the costs of virtual function calls.
+
+namespace grpc {
+namespace internal {
+
+#ifdef GPR_ABSEIL_SYNC
+
+using Mutex = absl::Mutex;
+using MutexLock = absl::MutexLock;
+using ReleasableMutexLock = absl::ReleasableMutexLock;
+using CondVar = absl::CondVar;
+
+#else
+
+class ABSL_LOCKABLE Mutex {
+ public:
+  Mutex() { gpr_mu_init(&mu_); }
+  ~Mutex() { gpr_mu_destroy(&mu_); }
+
+  Mutex(const Mutex&) = delete;
+  Mutex& operator=(const Mutex&) = delete;
+
+  void Lock() ABSL_EXCLUSIVE_LOCK_FUNCTION() { gpr_mu_lock(&mu_); }
+  void Unlock() ABSL_UNLOCK_FUNCTION() { gpr_mu_unlock(&mu_); }
+
+ private:
+  union {
+    gpr_mu mu_;
+    std::mutex do_not_use_sth_;
+#ifdef GPR_HAS_PTHREAD_H
+    pthread_mutex_t do_not_use_pth_;
+#endif
+  };
+
+  friend class CondVar;
+};
+
+class ABSL_SCOPED_LOCKABLE MutexLock {
+ public:
+  explicit MutexLock(Mutex* mu) ABSL_EXCLUSIVE_LOCK_FUNCTION(mu) : mu_(mu) {
+    mu_->Lock();
+  }
+  ~MutexLock() ABSL_UNLOCK_FUNCTION() { mu_->Unlock(); }
+
+  MutexLock(const MutexLock&) = delete;
+  MutexLock& operator=(const MutexLock&) = delete;
+
+ private:
+  Mutex* const mu_;
+};
+
+class ABSL_SCOPED_LOCKABLE ReleasableMutexLock {
+ public:
+  explicit ReleasableMutexLock(Mutex* mu) ABSL_EXCLUSIVE_LOCK_FUNCTION(mu)
+      : mu_(mu) {
+    mu_->Lock();
+  }
+  ~ReleasableMutexLock() ABSL_UNLOCK_FUNCTION() {
+    if (!released_) mu_->Unlock();
+  }
+
+  ReleasableMutexLock(const ReleasableMutexLock&) = delete;
+  ReleasableMutexLock& operator=(const ReleasableMutexLock&) = delete;
+
+  void Release() ABSL_UNLOCK_FUNCTION() {
+    GPR_DEBUG_ASSERT(!released_);
+    released_ = true;
+    mu_->Unlock();
+  }
+
+ private:
+  Mutex* const mu_;
+  bool released_ = false;
+};
+
+class CondVar {
+ public:
+  CondVar() { gpr_cv_init(&cv_); }
+  ~CondVar() { gpr_cv_destroy(&cv_); }
+
+  CondVar(const CondVar&) = delete;
+  CondVar& operator=(const CondVar&) = delete;
+
+  void Signal() { gpr_cv_signal(&cv_); }
+  void SignalAll() { gpr_cv_broadcast(&cv_); }
+
+  void Wait(Mutex* mu) {
+    gpr_cv_wait(&cv_, &mu->mu_, gpr_inf_future(GPR_CLOCK_REALTIME));
+  }
+
+ private:
+  gpr_cv cv_;
+};
+
+#endif  // GPR_ABSEIL_SYNC
+
+template <typename Predicate>
+GRPC_DEPRECATED("incompatible with thread safety analysis")
+static void WaitUntil(CondVar* cv, Mutex* mu, Predicate pred) {
+  while (!pred()) {
+    cv->Wait(mu);
+  }
+}
+
+}  // namespace internal
+}  // namespace grpc
+
+#endif  // GRPCPP_IMPL_SYNC_H