/* Copyright 2017 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/common_runtime/rendezvous_util.h"

#include "absl/synchronization/notification.h"
#include "tensorflow/core/lib/core/notification.h"
#include "tensorflow/core/lib/core/status_test_util.h"
#include "tensorflow/core/platform/test.h"

namespace tensorflow {
namespace {

class RendezvousUtilTest : public ::testing::Test {
 public:
  RendezvousUtilTest() { rendez_ = NewLocalRendezvous(); }

  ~RendezvousUtilTest() override { rendez_->Unref(); }

  Rendezvous* rendez_;
};

// string -> Tensor<string>
Tensor V(const std::string& content) {
  Tensor tensor(DT_STRING, TensorShape({}));
  tensor.scalar<tstring>()() = content;
  return tensor;
}

// Tensor<string> -> string
std::string V(const Tensor& tensor) {
  CHECK_EQ(tensor.dtype(), DT_STRING);
  CHECK(TensorShapeUtils::IsScalar(tensor.shape()));
  return tensor.scalar<tstring>()();
}

std::string MakeStringKey(const std::string& name) {
  return Rendezvous::CreateKey(
      "/job:localhost/replica:0/task:0/device:CPU:0", 0,
      "/job:localhost/replica:0/task:0/device:GPU:0", name, FrameAndIter(0, 0));
}

TEST_F(RendezvousUtilTest, SendBeforeRecv) {
  // Fire off sends before receive the tensors.
  TF_ASSERT_OK(SendTensorsToRendezvous(
      rendez_, nullptr, {}, {MakeStringKey("hello1"), MakeStringKey("hello2")},
      {V("hello1"), V("hello2")}));

  absl::Notification n;
  std::vector<Tensor> received_keys;
  RecvOutputsFromRendezvousAsync(
      rendez_, nullptr, {}, {MakeStringKey("hello1"), MakeStringKey("hello2")},
      &received_keys, [&n](const absl::Status& status) { n.Notify(); });
  n.WaitForNotification();

  EXPECT_EQ(2, received_keys.size());
  EXPECT_EQ("hello1", V(received_keys[0]));
  EXPECT_EQ("hello2", V(received_keys[1]));
}

TEST_F(RendezvousUtilTest, RecvBeforeSend) {
  // Fire off recvs, wait for a notification in the callback.
  absl::Notification n;
  std::vector<Tensor> received_keys;
  RecvOutputsFromRendezvousAsync(
      rendez_, nullptr, {}, {MakeStringKey("hello1"), MakeStringKey("hello2")},
      &received_keys, [&n](const absl::Status& status) { n.Notify(); });

  TF_ASSERT_OK(SendTensorsToRendezvous(
      rendez_, nullptr, {}, {MakeStringKey("hello1"), MakeStringKey("hello2")},
      {V("hello1"), V("hello2")}));

  n.WaitForNotification();

  EXPECT_EQ(2, received_keys.size());
  EXPECT_EQ("hello1", V(received_keys[0]));
  EXPECT_EQ("hello2", V(received_keys[1]));
}

/*
  This test setup is similar to the one above, while the main difference is
  that it Unref the rendezvous instance during Recv's done-callback.

  This is to mimic the use case where the caller thread is used to run the
  function and the done-callback. The done-callback unref the rendezvous, which
  triggers LocalRendezvous destruction if the ref-count reaches 0. However the
  destructor would wait until the done-callback to finish in order to finish
  delteting the rendezvous instance, thus leading to a deadlock.
*/
TEST(RendezvousUtilCallerThreadTest, RecvBeforeSend) {
  Rendezvous* rendez_ = NewLocalRendezvous();

  // Fire off recvs, wait for a notification in the callback.
  absl::Notification n;
  std::vector<Tensor> received_keys;
  RecvOutputsFromRendezvousAsync(
      rendez_, nullptr, {}, {MakeStringKey("hello1"), MakeStringKey("hello2")},
      &received_keys, [&n, rendez_](const absl::Status& status) {
        rendez_->Unref();
        n.Notify();
      });

  TF_ASSERT_OK(SendTensorsToRendezvous(
      rendez_, nullptr, {}, {MakeStringKey("hello1"), MakeStringKey("hello2")},
      {V("hello1"), V("hello2")}));

  n.WaitForNotification();

  ASSERT_EQ(2, received_keys.size());
  EXPECT_EQ("hello1", V(received_keys[0]));
  EXPECT_EQ("hello2", V(received_keys[1]));
}

}  // namespace
}  // namespace tensorflow
