/* 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/distributed_runtime/rpc/grpc_util.h"
#include "tensorflow/core/distributed_runtime/tensor_coding.h"

namespace tensorflow {

::grpc::Status GrpcMaybeUnparseProto(const protobuf::Message& src,
                                     grpc::ByteBuffer* dst) {
  bool own_buffer;
  return ::grpc::GenericSerialize<::grpc::ProtoBufferWriter,
                                  protobuf::Message>(src, dst, &own_buffer);
}

// GrpcMaybeUnparseProto from a string simply copies the string to the
// ByteBuffer.
::grpc::Status GrpcMaybeUnparseProto(const string& src, grpc::ByteBuffer* dst) {
  ::grpc::Slice s(src.data(), src.size());
  ::grpc::ByteBuffer buffer(&s, 1);
  dst->Swap(&buffer);
  return ::grpc::Status::OK;
}

bool GrpcMaybeParseProto(::grpc::ByteBuffer* src, protobuf::Message* dst) {
  ::grpc::ProtoBufferReader reader(src);
  return dst->ParseFromZeroCopyStream(&reader);
}

// Overload of GrpcParseProto so we can decode a TensorResponse without
// extra copying.  This overload is used by the RPCState class in
// grpc_state.h.
bool GrpcMaybeParseProto(::grpc::ByteBuffer* src, TensorResponse* dst) {
  ::tensorflow::GrpcByteSource byte_source(src);
  auto s = dst->ParseFrom(&byte_source);
  return s.ok();
}

// GrpcMaybeParseProto into a string simply copies bytes into the string.
bool GrpcMaybeParseProto(grpc::ByteBuffer* src, string* dst) {
  dst->clear();
  dst->reserve(src->Length());
  std::vector<::grpc::Slice> slices;
  if (!src->Dump(&slices).ok()) {
    return false;
  }
  for (const ::grpc::Slice& s : slices) {
    dst->append(reinterpret_cast<const char*>(s.begin()), s.size());
  }
  return true;
}

}  // namespace tensorflow