/* Copyright 2016 The TensorFlow Authors. All Rights Reserved.

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.
==============================================================================*/

#include "tensorflow/core/kernels/batching_util/fake_clock_env.h"

#include <string>

#include "absl/synchronization/notification.h"

namespace tensorflow {
namespace serving {
namespace test_util {

FakeClockEnv::FakeClockEnv(Env* wrapped) : EnvWrapper(wrapped) {}

void FakeClockEnv::AdvanceByMicroseconds(int micros) {
  {
    mutex_lock l(mu_);
    current_time_ += micros;
    for (auto it = sleeping_threads_.begin(); it != sleeping_threads_.end();) {
      if (current_time_ >= it->wake_time) {
        it->wake_notification->Notify();
        it = sleeping_threads_.erase(it);
      } else {
        ++it;
      }
    }
  }
}

void FakeClockEnv::BlockUntilSleepingThread(uint64_t wake_time) {
  for (;;) {
    {
      mutex_lock l(mu_);
      for (auto it = sleeping_threads_.begin(); it != sleeping_threads_.end();
           ++it) {
        if (it->wake_time == wake_time) {
          return;
        }
      }
    }
    EnvWrapper::SleepForMicroseconds(100);
  }
}

void FakeClockEnv::BlockUntilThreadsAsleep(int num_threads) {
  for (;;) {
    {
      mutex_lock l(mu_);
      if (num_threads <= sleeping_threads_.size()) {
        return;
      }
    }
    EnvWrapper::SleepForMicroseconds(100);
  }
}

uint64_t FakeClockEnv::NowMicros() const {
  {
    mutex_lock l(mu_);
    return current_time_;
  }
}

void FakeClockEnv::SleepForMicroseconds(int64_t micros) {
  if (micros == 0) {
    return;
  }

  absl::Notification wake_notification;
  {
    mutex_lock l(mu_);
    sleeping_threads_.push_back({current_time_ + micros, &wake_notification});
  }
  wake_notification.WaitForNotification();
}

}  // namespace test_util
}  // namespace serving
}  // namespace tensorflow
