// Safe container implementation  -*- C++ -*-

// Copyright (C) 2011-2026 Free Software Foundation, Inc.
//
// This file is part of the GNU ISO C++ Library.  This library is free
// software; you can redistribute it and/or modify it under the
// terms of the GNU General Public License as published by the
// Free Software Foundation; either version 3, or (at your option)
// any later version.

// This library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.

// Under Section 7 of GPL version 3, you are granted additional
// permissions described in the GCC Runtime Library Exception, version
// 3.1, as published by the Free Software Foundation.

// You should have received a copy of the GNU General Public License and
// a copy of the GCC Runtime Library Exception along with this program;
// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
// <http://www.gnu.org/licenses/>.

/** @file debug/safe_unordered_container.h
 *  This file is a GNU debug extension to the Standard C++ Library.
 */

#ifndef _GLIBCXX_DEBUG_SAFE_UNORDERED_CONTAINER_H
#define _GLIBCXX_DEBUG_SAFE_UNORDERED_CONTAINER_H 1

#include <debug/assertions.h>
#include <debug/macros.h>
#include <debug/functions.h>
#include <debug/safe_unordered_base.h>

namespace __gnu_debug
{
  template<typename _Container>
    class _Safe_unordered_container;

#ifdef __glibcxx_node_extract // >= C++17 && HOSTED
  template<typename _ExtractKey, typename _Source>
    struct _UContInvalidatePred
    {
      template<typename _Iterator>
	bool
	operator()(_Iterator __it) const
	{ return _M_source._M_cont().count(_ExtractKey{}(*__it)) == 0; }

      const _Safe_unordered_container<_Source>& _M_source;
    };

  template<typename _ExtractKey, typename _Source>
    struct _UMContInvalidatePred
    {
      template<typename _Iterator>
	bool
	operator()(_Iterator __it) const
	{
	  auto __rng =
	    _M_source._M_cont()._M_base().equal_range(_ExtractKey{}(*__it));
	  for (auto __rit = __rng.first;
	       __rit != __rng.second; ++__rit)
	    {
	      if (__it == __rit)
		return false;
	    }

	  return true;
	}

      const _Safe_unordered_container<_Source>& _M_source;
    };

  template<typename _Source, typename _InvalidatePred>
    struct _UContMergeGuard
    {
      _UContMergeGuard(_Safe_unordered_container<_Source>& __src) noexcept
      : _M_source(__src), _M_size(__src._M_cont().size()), _M_pred { __src }
      { }

      _UContMergeGuard(const _UContMergeGuard&) = delete;

      ~_UContMergeGuard()
      {
	const std::size_t __size = _M_source._M_cont().size();
	if (__size == _M_size)
	  return;

	__try
	  {
	    if (__size == 0)
	      _M_source._M_invalidate_all();
	    else
	      _M_source._M_invalidate_all_if(_M_pred);
	  }
	__catch(...)
	{
	  _M_source._M_invalidate_all();
	}
      }

      _Safe_unordered_container<_Source>& _M_source;
      const std::size_t _M_size;
      _InvalidatePred _M_pred;
  };
#endif // >= C++17 && HOSTED

  /**
   * @brief Base class for constructing a @a safe unordered container type
   * that tracks iterators that reference it.
   *
   * The class template %_Safe_unordered_container simplifies the
   * construction of @a safe unordered containers that track the iterators
   * that reference the container, so that the iterators are notified of
   * changes in the container that may affect their operation, e.g., if
   * the container invalidates its iterators or is destructed. This class
   * template may only be used by deriving from it and passing the name
   * of the derived class as its template parameter via the curiously
   * recurring template pattern. The derived class must have @c
   * iterator and @c const_iterator types that are instantiations of
   * class template _Safe_iterator for this container and @c local_iterator
   * and @c const_local_iterator types that are instantiations of class
   * template _Safe_local_iterator for this container. Iterators will
   * then be tracked automatically.
   */
  template<typename _Container>
    class _Safe_unordered_container : public _Safe_unordered_container_base
    {
      const _Container&
      _M_cont() const noexcept
      { return *static_cast<const _Container*>(this); }

      const _Safe_unordered_container*
      _M_self() const
      { return this; }

    protected:
#ifdef __glibcxx_node_extract // >= C++17 && HOSTED
      template<typename _ExtractKey, typename _Source>
	friend struct ::__gnu_debug::_UContInvalidatePred;

      template<typename _ExtractKey, typename _Source>
	friend struct ::__gnu_debug::_UMContInvalidatePred;

      template<typename _Source, typename _InvalidatePred>
	friend struct ::__gnu_debug::_UContMergeGuard;

      template<typename _ExtractKey, typename _Source>
	static _UContMergeGuard<_Source,
				_UContInvalidatePred<_ExtractKey, _Source>>
	_S_uc_guard(_ExtractKey, _Safe_unordered_container<_Source>& __src)
	{
	  typedef _UContInvalidatePred<_ExtractKey, _Source> _InvalidatePred;
	  return _UContMergeGuard<_Source, _InvalidatePred>(__src);
	}

      template<typename _ExtractKey, typename _Source>
	static _UContMergeGuard<_Source,
				_UMContInvalidatePred<_ExtractKey, _Source>>
	_S_umc_guard(_ExtractKey, _Safe_unordered_container<_Source>& __src)
	{
	  typedef _UMContInvalidatePred<_ExtractKey, _Source> _InvalidatePred;
	  return _UContMergeGuard<_Source, _InvalidatePred>(__src);
	}
#endif // >= C++17 && HOSTED

      void
      _M_invalidate_all()
      {
	__gnu_cxx::__scoped_lock sentry(_M_self()->_M_get_mutex());
	auto __end = _M_cont()._M_base().cend();
	_M_invalidate_if(
	  [__end](decltype(__end) __it)
	  { return __it != __end; },
	  sentry);

	auto __local_end = _M_cont()._M_base().cend(0);
	_M_invalidate_local_if(
	  [__local_end](decltype(__local_end) __it)
	  { return __it != __local_end; },
	  sentry);
      }

      template<typename _Predicate>
	void
	_M_invalidate_all_if(_Predicate __pred)
	{
	  __gnu_cxx::__scoped_lock sentry(_M_self()->_M_get_mutex());
	  _M_invalidate_if(__pred, sentry);
	  _M_invalidate_local_if(__pred, sentry);
	}

      template<typename _VictimIt>
	void
	_M_invalidate(_VictimIt __victim)
	{
	  __gnu_cxx::__scoped_lock sentry(_M_self()->_M_get_mutex());
	  _M_invalidate(__victim, sentry);
	}

      template<typename _VictimIt>
	void
	_M_invalidate(_VictimIt __victim, const __gnu_cxx::__scoped_lock& __lock)
	{
	  auto __end = _M_cont()._M_base().cend();
	  _M_invalidate_if(
	    [__victim](decltype(__end) __it)
	    { return __it == __victim; },
	    __lock);

	  auto __local_end = _M_cont()._M_base().cend(0);
	  _M_invalidate_local_if(
	    [__victim](decltype(__local_end) __it)
	    { return __it == __victim; },
	    __lock);
	}

    private:
      /** Invalidates all iterators @c x that reference this container,
	  are not singular, and for which @c __pred(x) returns @c
	  true. @c __pred will be invoked with the normal iterators nested
	  in the safe ones. */
      template<typename _Predicate>
	void
	_M_invalidate_if(_Predicate __pred, const __gnu_cxx::__scoped_lock&);

      /** Invalidates all local iterators @c x that reference this container,
	  are not singular, and for which @c __pred(x) returns @c
	  true. @c __pred will be invoked with the normal local iterators
	  nested in the safe ones. */
      template<typename _Predicate>
	void
	_M_invalidate_local_if(_Predicate __pred,
			       const __gnu_cxx::__scoped_lock&);
    };
} // namespace __gnu_debug

#include <debug/safe_unordered_container.tcc>

#endif