/* Copyright 2019 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/eager/tensor_handle_data.h"

#include <utility>
#include <variant>

#include "tensorflow/core/common_runtime/eager/eager_executor.h"
#include "tensorflow/core/lib/core/status.h"
#include "tensorflow/core/lib/strings/strcat.h"
#include "tensorflow/core/profiler/lib/traceme.h"

namespace tensorflow {

absl::Status LocalTensorHandleData::Tensor(const tensorflow::Tensor** t) const {
  TF_RETURN_IF_ERROR(WaitReady("Tensor"));

  *t = &tensor_;

  return absl::OkStatus();
}

absl::Status LocalTensorHandleData::TensorValue(tensorflow::TensorValue* t) {
  TF_RETURN_IF_ERROR(WaitReady("TensorValue"));

  tensorflow::Tensor& tensor = tensor_;
  *t = tensorflow::TensorValue(&tensor);

  return absl::OkStatus();
}

absl::Status LocalTensorHandleData::Shape(TensorShape* shape) const {
  TF_RETURN_IF_ERROR(WaitReady("Shape"));

  *shape = tensor_.shape();

  return absl::OkStatus();
}

absl::Status LocalTensorHandleData::NumDims(int* num_dims) const {
  TF_RETURN_IF_ERROR(WaitReady("NumDims"));

  *num_dims = tensor_.dims();

  return absl::OkStatus();
}

absl::Status LocalTensorHandleData::Dim(int dim_index, int64_t* dim) const {
  TF_RETURN_IF_ERROR(WaitReady("Dim"));

  *dim = tensor_.dim_size(dim_index);

  return absl::OkStatus();
}

absl::Status LocalTensorHandleData::NumElements(int64_t* num_elements) const {
  TF_RETURN_IF_ERROR(WaitReady("NumElements"));

  *num_elements = tensor_.NumElements();

  return absl::OkStatus();
}

absl::Status LocalTensorHandleData::Unprotect() {
  if (!IsReady()) {
    return errors::Internal("Cannot unprotect a non-ready tensor");
  }

  forwarding_protection_tensor_ = tensorflow::Tensor();

  return absl::OkStatus();
}

absl::Status LocalTensorHandleData::SetTensor(tensorflow::Tensor&& t) {
  DCHECK(!IsReady()) << "SetTensor is only called on non-ready handles.";

  tensor_ = std::move(t);
  // Create copy of original tensor to avoid forwarding
  forwarding_protection_tensor_ = tensor_;

  auto& state = std::get<BlockingControl>(ctrl_);
  state.SetReady();

  return absl::OkStatus();
}

string LocalTensorHandleData::DebugString() const {
  if (IsReady()) {
    return tensor_.DeviceSafeDebugString();
  } else {
    return "LocalTensorHandleData";
  }
}

void LocalTensorHandleData::BlockingControl::SetReady() {
  mutex_lock l(mu_);
  is_ready_ = true;
}

absl::Status LocalTensorHandleData::BlockingControl::WaitReady(
    const char* caller) const {
  tf_shared_lock l(mu_);
  if (!is_ready_) {
    tsl::profiler::TraceMe activity(
        [caller] { return absl::StrCat(caller, " WaitReady"); },

        tsl::profiler::TraceMeLevel::kInfo);
    DVLOG(3) << "WaitReady: " << caller << " " << this;
    mu_.Await(Condition(&is_ready_));
  }

  return is_poisoned_;
}

void LocalTensorHandleData::BlockingControl::Poison(absl::Status status) {
  mutex_lock l(mu_);
  if (is_ready_) {
    LOG(ERROR) << "Poison can only be called on non-ready handle: " << this;
    return;
  }
  is_poisoned_ = status;
  is_ready_ = true;
}

}  // namespace tensorflow
