//===------------------SharedCluster.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_SHAREDCLUSTER_H

#define LLDB_UTILITY_SHAREDCLUSTER_H

#include "lldb/Utility/LLDBAssert.h"

#include "llvm/ADT/STLExtras.h"

#include "llvm/ADT/SmallPtrSet.h"

#include <memory>

#include <mutex>

namespace lldb_private {

template <class T>

class ClusterManager : public std::enable_shared_from_this<ClusterManager<T>> {

public:

  static std::shared_ptr<ClusterManager> Create() {

    return std::shared_ptr<ClusterManager>(new ClusterManager());

  }

  ~ClusterManager() {

    for (T *obj : m_objects)

      delete obj;

  }

  void ManageObject(T *new_object) {

    std::lock_guard<std::mutex> guard(m_mutex);

    auto ret = m_objects.insert(new_object);

    assert(ret.second && "ManageObject called twice for the same object?");

    (void)ret;

  }

  std::shared_ptr<T> GetSharedPointer(T *desired_object) {

    std::lock_guard<std::mutex> guard(m_mutex);

    auto this_sp = this->shared_from_this();

    size_t count =  m_objects.count(desired_object);

    if (count == 0) {

      lldbassert(false && "object not found in shared cluster when expected");

      desired_object = nullptr;

    }

    return {std::move(this_sp), desired_object};

  }

private:

  ClusterManager() : m_objects() {}

  // The cluster manager is used primarily to manage the

  // children of root ValueObjects. So it will always have

  // one element - the root.  Pointers will often have dynamic

  // values, so having 2 entries is pretty common.  It's also

  // pretty common to have small (2,3) structs, so setting the

  // static size to 4 will cover those cases with no allocations

  // w/o wasting too much space.

  llvm::SmallPtrSet<T *, 4> m_objects;

  std::mutex m_mutex;

};

} // namespace lldb_private

#endif // LLDB_UTILITY_SHAREDCLUSTER_H