include/lldb/Utility/Baton.h

//===-- Baton.h -------------------------------------------------*- C++ -*-===//
//
//                     The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//

#ifndef lldb_Baton_h_
#define lldb_Baton_h_

#include "lldb/lldb-enumerations.h" // for DescriptionLevel
#include "lldb/lldb-public.h"

#include <memory> // for unique_ptr

namespace lldb_private {
class Stream;
}

namespace lldb_private {

//----------------------------------------------------------------------
/// @class Baton Baton.h "lldb/Core/Baton.h"
/// @brief A class designed to wrap callback batons so they can cleanup
///        any acquired resources
///
/// This class is designed to be used by any objects that have a
/// callback function that takes a baton where the baton might need to
/// free/delete/close itself.
///
/// The default behavior is to not free anything. Subclasses can
/// free any needed resources in their destructors.
//----------------------------------------------------------------------
class Baton {
public:
  Baton() {}
  virtual ~Baton() {}

  virtual void *data() = 0;

  virtual void GetDescription(Stream *s,
                              lldb::DescriptionLevel level) const = 0;
};

class UntypedBaton : public Baton {
public:
  UntypedBaton(void *Data) : m_data(Data) {}
  virtual ~UntypedBaton() {
    // The default destructor for an untyped baton does NOT attempt to clean up
    // anything in m_data.
  }

  void *data() override { return m_data; }
  void GetDescription(Stream *s, lldb::DescriptionLevel level) const override;

  void *m_data; // Leave baton public for easy access
};

template <typename T> class TypedBaton : public Baton {
public:
  explicit TypedBaton(std::unique_ptr<T> Item) : Item(std::move(Item)) {}

  T *getItem() { return Item.get(); }
  const T *getItem() const { return Item.get(); }

  void *data() override { return Item.get(); }
  virtual void GetDescription(Stream *s,
                              lldb::DescriptionLevel level) const override {}

protected:
  std::unique_ptr<T> Item;
};

} // namespace lldb_private

#endif // lldb_Baton_h_