/* Copyright (c) 2016 PaddlePaddle Authors. All Rights Reserve.

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. */

#pragma once
#include "paddle/framework/enforce.h"
#include "paddle/platform/place.h"
#include "unsupported/Eigen/CXX11/Tensor"

namespace paddle {
namespace platform {

class DeviceContext {
 public:
  virtual ~DeviceContext() {}

  template <typename DeviceType>
  inline DeviceType get_eigen_device();

  virtual Place GetPlace() const = 0;
};

class CPUDeviceContext : public DeviceContext {
 public:
  Eigen::DefaultDevice eigen_device() {
    if (!eigen_device_) {
      eigen_device_ = new Eigen::DefaultDevice();
    }
    return *eigen_device_;
  }

  Place GetPlace() const override {
    Place retv = CPUPlace();
    return retv;
  }

 private:
  Eigen::DefaultDevice* eigen_device_{nullptr};
};

template <>
Eigen::DefaultDevice DeviceContext::get_eigen_device<Eigen::DefaultDevice>() {
  return dynamic_cast<CPUDeviceContext*>(this)->eigen_device();
}
}  // namespace platform
}  // namespace paddle