Function CopyGraph

tensorflow/c/c_api.cc:1827–1865

Copies `src_graph` into `dst_graph`. Any node in `src_graph` with input `src_inputs[i]` will have that input replaced with `dst_inputs[i]`. `prefix` will be prepended to copied node names. `control_deps` are nodes in `dst_graph` that the copied `src_graph` nodes will have control dependencies on. `return_nodes` are nodes in `src_graph`, and the new corresponding nodes in `dst_graph` will be retur

// on. `return_nodes` are nodes in `src_graph`, and the new corresponding nodes
// in `dst_graph` will be returned. `return_nodes` must be non-null.
Status CopyGraph(Graph* src_graph, Graph* dst_graph,
                 tensorflow::ShapeRefiner* dst_refiner,
                 const TF_Output* src_inputs,
                 const std::vector<tensorflow::Output>& dst_inputs,
                 const string& prefix,
                 const std::vector<tensorflow::Operation>& control_deps,
                 const TF_Output* nodes_to_return, int nreturn_nodes,
                 std::vector<tensorflow::Output>* return_nodes) {
  DCHECK(return_nodes != nullptr);
  GraphDef gdef;
  src_graph->ToGraphDef(&gdef);

  tensorflow::ImportGraphDefOptions opts;
  opts.prefix = prefix;

  for (int i = 0; i < dst_inputs.size(); ++i) {
    opts.input_map[ToTensorId(src_inputs[i])] =
        TensorId(dst_inputs[i].node()->name(), dst_inputs[i].index());
  }
  opts.skip_mapped_nodes = true;

  for (const tensorflow::Operation& op : control_deps) {
    opts.control_dependencies.push_back(op.node()->name());
  }

  for (int i = 0; i < nreturn_nodes; ++i) {
    opts.return_tensors.push_back(ToTensorId(nodes_to_return[i]));
  }

  // TODO(skyewm): change to OutputTensor
  tensorflow::ImportGraphDefResults results;
  TF_RETURN_IF_ERROR(
      ImportGraphDef(opts, gdef, dst_graph, dst_refiner, &results));

  for (const auto& pair : results.return_tensors) {
    return_nodes->emplace_back(pair.first, pair.second);
  }
  return Status::OK();
}

bool ValidateConstWhileParams(const TF_WhileParams& params, TF_Status* s) {
  if (params.cond_graph == nullptr || params.body_graph == nullptr ||