Baton.h

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//===-- Baton.h -------------------------------------------------*- C++ -*-===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
 
#ifndef LLDB_UTILITY_BATON_H
#define LLDB_UTILITY_BATON_H
 
#include "lldb/lldb-enumerations.h"
#include "lldb/lldb-public.h"
 
#include "llvm/Support/raw_ostream.h"
 
#include <memory>
 
namespace lldb_private {
class Stream;
}
 
namespace lldb_private {
 
/// \class Baton Baton.h "lldb/Core/Baton.h"
/// 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() = default;
  virtual ~Baton() = default;
 
  virtual void *data() = 0;
 
  virtual void GetDescription(llvm::raw_ostream &s,
                              lldb::DescriptionLevel level,
                              unsigned indentation) const = 0;
};
 
class UntypedBaton : public Baton {
public:
  UntypedBaton(void *Data) : m_data(Data) {}
  ~UntypedBaton() override {
    // 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(llvm::raw_ostream &s, lldb::DescriptionLevel level,
                      unsigned indentation) 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(); }
  void GetDescription(llvm::raw_ostream &s, lldb::DescriptionLevel level,
                      unsigned indentation) const override {}
 
protected:
  std::unique_ptr<T> Item;
};
 
} // namespace lldb_private
 
#endif // LLDB_UTILITY_BATON_H