/* Copyright (c) 2021 PaddlePaddle 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. */

#pragma once

#include "paddle/fluid/framework/data_type.h"
#include "paddle/fluid/framework/op_registry.h"
#include "paddle/fluid/framework/var_type.h"
#include "paddle/fluid/platform/device_context.h"

namespace paddle {
namespace platform {
class DeviceContext;
}  // namespace platform
}  // namespace paddle

namespace paddle {
namespace framework {
class LoDTensor;
class Variable;
class SelectedRows;
}  // namespace framework
}  // namespace paddle

namespace paddle {
namespace operators {
class MemcpyD2HFunctor {
 public:
  MemcpyD2HFunctor(framework::Variable *out,
                   const platform::DeviceContext &dev_ctx,
                   const int dst_place_type)
      : out_(out), dev_ctx_(dev_ctx), dst_place_type_(dst_place_type) {}

  void operator()(const framework::LoDTensor &lod_tensor) const {
    auto &out_tensor = *out_->GetMutable<framework::LoDTensor>();
    CopyLoDTensor(lod_tensor, out_tensor);
  }

  void operator()(const framework::LoDTensorArray &array) const {
    auto &out_array = *out_->GetMutable<framework::LoDTensorArray>();
    out_array.clear();
    out_array.resize(array.size());

    for (size_t i = 0; i < array.size(); i++) {
      CopyLoDTensor(array[i], out_array[i]);
    }
  }

  void operator()(const framework::SelectedRows &rows) const {
    // (JZ-LIANG) to support SelectedRows
    PADDLE_THROW(platform::errors::Unimplemented(
        "Memcpy for SelectedRows is NOT support yet."));
  }

  template <typename T>
  void operator()(const T &v) const {
    PADDLE_ENFORCE_EQ(
        true, false,
        platform::errors::PermissionDenied(
            "Not support type for Memcpy  op with type %s", typeid(T).name()));
  }

 private:
  void CopyLoDTensor(const framework::LoDTensor &src,
                     framework::LoDTensor &dst) const {  // NOLINT
    if (dst_place_type_ == 1) {
      framework::TensorCopy(src, platform::CUDAPinnedPlace(), dev_ctx_, &dst);
    } else if (dst_place_type_ == 0) {
      framework::TensorCopySync(src, platform::CPUPlace(), &dst);
    } else {
      PADDLE_THROW(platform::errors::Unimplemented(
          "memcpy dst_place_type: %d is not supported yet.", dst_place_type_));
    }
    dst.set_lod(src.lod());
  }

  framework::Variable *out_;
  const platform::DeviceContext &dev_ctx_;
  const int dst_place_type_;
};

}  // namespace operators
}  // namespace paddle