Roll forward to cl/314747126

Signed-off-by: Alexey Polyudov <apolyudov@google.com>
Change-Id: Ie19e006429b138b3768e97dae971a43fdc5ef8bf

cpp/platform/impl/shared/posix_condition_variable.cc

@@ -0,0 +1,42 @@
+// Copyright 2020 Google LLC
+//
+// 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
+//
+//     https://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.
+
+#include "platform/impl/shared/posix_condition_variable.h"
+
+namespace location {
+namespace nearby {
+
+PosixConditionVariable::PosixConditionVariable(Ptr<PosixLock> lock)
+    : lock_(lock), attr_(), cond_() {
+  pthread_condattr_init(&attr_);
+
+  pthread_cond_init(&cond_, &attr_);
+}
+
+PosixConditionVariable::~PosixConditionVariable() {
+  pthread_cond_destroy(&cond_);
+
+  pthread_condattr_destroy(&attr_);
+}
+
+void PosixConditionVariable::notify() { pthread_cond_broadcast(&cond_); }
+
+Exception::Value PosixConditionVariable::wait() {
+  pthread_cond_wait(&cond_, &(lock_->mutex_));
+
+  return Exception::kSuccess;
+}
+
+}  // namespace nearby
+}  // namespace location