#include "tensorflow/core/graph/while_context.h"
#include "tensorflow/core/lib/gtl/map_util.h"
#include "tensorflow/core/platform/macros.h"

namespace tensorflow {
namespace {

struct OutputHash {
  uint64 operator()(const Output& x) const { return x.hash(); }
};

struct OutputEq {
  bool operator()(const Output& x, const Output& y) const {
    return (x.node() == y.node()) && (x.index() == y.index());
  }

  /// to feed them with. See `Input::Initializer` for details on what can be
  /// used as feed values.
  typedef std::unordered_map<Output, Input::Initializer, OutputHash> FeedType;

  /// Create a new session to evaluate the graph contained in `scope` by
  /// connecting to the TensorFlow runtime specified by `target`.
  ClientSession(const Scope& scope, const string& target);

  uint64 hash() const { return op_.hash(index_); }

 private:
  Operation op_ = Operation(nullptr);
  int32 index_ = 0;
};

/// Hash class that can be used for e.g. storing Outputs in an unordered_map
struct OutputHash {
  std::size_t operator()(const Output& output) const {
    return Hash64Combine(std::hash<Node*>()(output.node()),
                         std::hash<int32>()(output.index()));
  }
};