/* Copyright 2003-2006 Joaquín M López Muñoz.

 * Distributed under the Boost Software License, Version 1.0.

 * (See accompanying file LICENSE_1_0.txt or copy at

 * http://www.boost.org/LICENSE_1_0.txt)

 *

 * See http://www.boost.org/libs/multi_index for library home page.

 */

#ifndef BOOST_MULTI_INDEX_DETAIL_SAFE_MODE_HPP

#define BOOST_MULTI_INDEX_DETAIL_SAFE_MODE_HPP

#if defined(_MSC_VER)&&(_MSC_VER>=1200)

#pragma once

#endif

/* Safe mode machinery, in the spirit of Cay Hortmann's "Safe STL"

 * (http://www.horstmann.com/safestl.html).

 * In this mode, containers of type Container are derived from

 * safe_container<Container>, and their corresponding iterators

 * are wrapped with safe_iterator. These classes provide

 * an internal record of which iterators are at a given moment associated

 * to a given container, and properly mark the iterators as invalid

 * when the container gets destroyed.

 * Iterators are chained in a single attached list, whose header is

 * kept by the container. More elaborate data structures would yield better

 * performance, but I decided to keep complexity to a minimum since

 * speed is not an issue here.

 * Safe mode iterators automatically check that only proper operations

 * are performed on them: for instance, an invalid iterator cannot be

 * dereferenced. Additionally, a set of utilty macros and functions are

 * provided that serve to implement preconditions and cooperate with

 * the framework within the container.

 * Iterators can also be unchecked, i.e. they do not have info about

 * which container they belong in. This situation arises when the iterator

 * is restored from a serialization archive: only information on the node

 * is available, and it is not possible to determine to which container

 * the iterator is associated to. The only sensible policy is to assume

 * unchecked iterators are valid, though this can certainly generate false

 * positive safe mode checks.

 * This is not a full-fledged safe mode framework, and is only intended

 * for use within the limits of Boost.MultiIndex.

 */

/* Assertion macros. These resolve to no-ops if

 * !defined(BOOST_MULTI_INDEX_ENABLE_SAFE_MODE).

 */

#if !defined(BOOST_MULTI_INDEX_ENABLE_SAFE_MODE)

#undef BOOST_MULTI_INDEX_SAFE_MODE_ASSERT

#define BOOST_MULTI_INDEX_SAFE_MODE_ASSERT(expr,error_code) ((void)0)

#else

#if !defined(BOOST_MULTI_INDEX_SAFE_MODE_ASSERT)

#include <boost/assert.hpp>

#define BOOST_MULTI_INDEX_SAFE_MODE_ASSERT(expr,error_code) BOOST_ASSERT(expr)

#endif

#endif

#define BOOST_MULTI_INDEX_CHECK_VALID_ITERATOR(it)                           \

  BOOST_MULTI_INDEX_SAFE_MODE_ASSERT(                                        \

    safe_mode::check_valid_iterator(it),                                     \

    safe_mode::invalid_iterator);

#define BOOST_MULTI_INDEX_CHECK_DEREFERENCEABLE_ITERATOR(it)                 \

  BOOST_MULTI_INDEX_SAFE_MODE_ASSERT(                                        \

    safe_mode::check_dereferenceable_iterator(it),                           \

    safe_mode::not_dereferenceable_iterator);

#define BOOST_MULTI_INDEX_CHECK_INCREMENTABLE_ITERATOR(it)                   \

  BOOST_MULTI_INDEX_SAFE_MODE_ASSERT(                                        \

    safe_mode::check_incrementable_iterator(it),                             \

    safe_mode::not_incrementable_iterator);

#define BOOST_MULTI_INDEX_CHECK_DECREMENTABLE_ITERATOR(it)                   \

  BOOST_MULTI_INDEX_SAFE_MODE_ASSERT(                                        \

    safe_mode::check_decrementable_iterator(it),                             \

    safe_mode::not_decrementable_iterator);

#define BOOST_MULTI_INDEX_CHECK_IS_OWNER(it,cont)                            \

  BOOST_MULTI_INDEX_SAFE_MODE_ASSERT(                                        \

    safe_mode::check_is_owner(it,cont),                                      \

    safe_mode::not_owner);

#define BOOST_MULTI_INDEX_CHECK_SAME_OWNER(it0,it1)                          \

  BOOST_MULTI_INDEX_SAFE_MODE_ASSERT(                                        \

    safe_mode::check_same_owner(it0,it1),                                    \

    safe_mode::not_same_owner);

#define BOOST_MULTI_INDEX_CHECK_VALID_RANGE(it0,it1)                         \

  BOOST_MULTI_INDEX_SAFE_MODE_ASSERT(                                        \

    safe_mode::check_valid_range(it0,it1),                                   \

    safe_mode::invalid_range);

#define BOOST_MULTI_INDEX_CHECK_OUTSIDE_RANGE(it,it0,it1)                    \

  BOOST_MULTI_INDEX_SAFE_MODE_ASSERT(                                        \

    safe_mode::check_outside_range(it,it0,it1),                              \

    safe_mode::inside_range);

#define BOOST_MULTI_INDEX_CHECK_IN_BOUNDS(it,n)                              \

  BOOST_MULTI_INDEX_SAFE_MODE_ASSERT(                                        \

    safe_mode::check_in_bounds(it,n),                                        \

    safe_mode::out_of_bounds);

#define BOOST_MULTI_INDEX_CHECK_DIFFERENT_CONTAINER(cont0,cont1)             \

  BOOST_MULTI_INDEX_SAFE_MODE_ASSERT(                                        \

    safe_mode::check_different_container(cont0,cont1),                       \

    safe_mode::same_container);

#if defined(BOOST_MULTI_INDEX_ENABLE_SAFE_MODE)

#include <boost/config.hpp> /* keep it first to prevent nasty warns in MSVC */

#include <algorithm>

#include <boost/detail/iterator.hpp>

#include <boost/multi_index/detail/access_specifier.hpp>

#include <boost/multi_index/detail/iter_adaptor.hpp>

#include <boost/multi_index/safe_mode_errors.hpp>

#include <boost/noncopyable.hpp>

#if !defined(BOOST_MULTI_INDEX_DISABLE_SERIALIZATION)

#include <boost/serialization/split_member.hpp>

#endif

#if defined(BOOST_HAS_THREADS)

#include <boost/detail/lightweight_mutex.hpp>

#endif

namespace boost{

namespace multi_index{

namespace safe_mode{

/* Checking routines. Assume the best for unchecked iterators

 * (i.e. they pass the checking when there is not enough info

 * to know.)

 */

template<typename Iterator>

inline bool check_valid_iterator(const Iterator& it)

{

  return it.valid()||it.unchecked();

}

template<typename Iterator>

inline bool check_dereferenceable_iterator(const Iterator& it)

{

  return it.valid()&&it!=it.owner()->end()||it.unchecked();

}

template<typename Iterator>

inline bool check_incrementable_iterator(const Iterator& it)

{

  return it.valid()&&it!=it.owner()->end()||it.unchecked();

}

template<typename Iterator>

inline bool check_decrementable_iterator(const Iterator& it)

{

  return it.valid()&&it!=it.owner()->begin()||it.unchecked();

}

template<typename Iterator>

inline bool check_is_owner(

  const Iterator& it,const typename Iterator::container_type& cont)

{

  return it.valid()&&it.owner()==&cont||it.unchecked();

}

template<typename Iterator>

inline bool check_same_owner(const Iterator& it0,const Iterator& it1)

{

  return it0.valid()&&it1.valid()&&it0.owner()==it1.owner()||

         it0.unchecked()||it1.unchecked();

}

template<typename Iterator>

inline bool check_valid_range(const Iterator& it0,const Iterator& it1)

{

  if(!check_same_owner(it0,it1))return false;

  if(it0.valid()){

    Iterator last=it0.owner()->end();

    if(it1==last)return true;

    for(Iterator first=it0;first!=last;++first){

      if(first==it1)return true;

    }

    return false;

  }

  return true;

}

template<typename Iterator>

inline bool check_outside_range(

  const Iterator& it,const Iterator& it0,const Iterator& it1)

{

  if(!check_same_owner(it0,it1))return false;

  if(it0.valid()){

    Iterator last=it0.owner()->end();

    bool found=false;

    Iterator first=it0;

    for(;first!=last;++first){

      if(first==it1)break;

      /* crucial that this check goes after previous break */

      if(first==it)found=true;

    }

    if(first!=it1)return false;

    return !found;

  }

  return true;

}

template<typename Iterator,typename Difference>

inline bool check_in_bounds(const Iterator& it,Difference n)

{

  if(it.unchecked())return true;

  if(!it.valid())   return false;

  if(n>0)           return it.owner()->end()-it>=n;

  else              return it.owner()->begin()-it<=n;

}

template<typename Container>

inline bool check_different_container(

  const Container& cont0,const Container& cont1)

{

  return &cont0!=&cont1;

}

/* Invalidates all iterators equivalent to that given. Safe containers

 * must call this when deleting elements: the safe mode framework cannot

 * perform this operation automatically without outside help.

 */

template<typename Iterator>

inline void detach_equivalent_iterators(Iterator& it)

{

  if(it.valid()){

    Iterator *prev_,*next_;

    for(

      prev_=static_cast<Iterator*>(&it.cont->header);

      (next_=static_cast<Iterator*>(prev_->next))!=0;){

      if(next_!=&it&&*next_==it){

        prev_->next=next_->next;

        next_->cont=0;

      }

      else prev_=next_;

    }

    it.detach();

  }

}

template<typename Container> class safe_container; /* fwd decl. */

} /* namespace multi_index::safe_mode */

namespace detail{

class safe_container_base;                 /* fwd decl. */

class safe_iterator_base

{

public:

  bool valid()const{return cont!=0;}

  bool unchecked()const{return unchecked_;}

  inline void detach();

  void uncheck()

  {

    detach();

    unchecked_=true;

  }

protected:

  safe_iterator_base():cont(0),next(0),unchecked_(false){}

  explicit safe_iterator_base(safe_container_base* cont_):

    unchecked_(false)

  {

    attach(cont_);

  }

  safe_iterator_base(const safe_iterator_base& it):

    unchecked_(it.unchecked_)

  {

    attach(it.cont);

  }

  safe_iterator_base& operator=(const safe_iterator_base& it)

  {

    unchecked_=it.unchecked_;

    safe_container_base* new_cont=it.cont;

    if(cont!=new_cont){

      detach();

      attach(new_cont);

    }

    return *this;

  }

  ~safe_iterator_base()

  {

    detach();

  }

  const safe_container_base* owner()const{return cont;}

BOOST_MULTI_INDEX_PRIVATE_IF_MEMBER_TEMPLATE_FRIENDS:

  friend class safe_container_base;

#if !defined(BOOST_NO_MEMBER_TEMPLATE_FRIENDS)

  template<typename>          friend class safe_mode::safe_container;

  template<typename Iterator> friend

    void safe_mode::detach_equivalent_iterators(Iterator&);

#endif

  inline void attach(safe_container_base* cont_);

  safe_container_base* cont;

  safe_iterator_base*  next;

  bool                 unchecked_;

};

class safe_container_base:private noncopyable

{

public:

  safe_container_base(){}

BOOST_MULTI_INDEX_PROTECTED_IF_MEMBER_TEMPLATE_FRIENDS:

  friend class safe_iterator_base;

#if !defined(BOOST_NO_MEMBER_TEMPLATE_FRIENDS)

  template<typename Iterator> friend

    void safe_mode::detach_equivalent_iterators(Iterator&);

#endif

  ~safe_container_base()

  {

    /* Detaches all remaining iterators, which by now will

     * be those pointing to the end of the container.

     */

    for(safe_iterator_base* it=header.next;it;it=it->next)it->cont=0;

    header.next=0;

  }

  void swap(safe_container_base& x)

  {

    for(safe_iterator_base* it0=header.next;it0;it0=it0->next)it0->cont=&x;

    for(safe_iterator_base* it1=x.header.next;it1;it1=it1->next)it1->cont=this;

    std::swap(header.cont,x.header.cont);

    std::swap(header.next,x.header.next);

  }

  safe_iterator_base header;

#if defined(BOOST_HAS_THREADS)

  boost::detail::lightweight_mutex mutex;

#endif

};

void safe_iterator_base::attach(safe_container_base* cont_)

{

  cont=cont_;

  if(cont){

#if defined(BOOST_HAS_THREADS)

    boost::detail::lightweight_mutex::scoped_lock lock(cont->mutex);

#endif

    next=cont->header.next;

    cont->header.next=this;

  }

}

void safe_iterator_base::detach()

{

  if(cont){

#if defined(BOOST_HAS_THREADS)

    boost::detail::lightweight_mutex::scoped_lock lock(cont->mutex);

#endif

    safe_iterator_base *prev_,*next_;

    for(prev_=&cont->header;(next_=prev_->next)!=this;prev_=next_){}

    prev_->next=next;

    cont=0;

  }

}

} /* namespace multi_index::detail */

namespace safe_mode{

/* In order to enable safe mode on a container:

 *   - The container must derive from safe_container<container_type>,

 *   - iterators must be generated via safe_iterator, which adapts a

 *     preexistent unsafe iterator class.

 */

template<typename Container>

class safe_container;

template<typename Iterator,typename Container>

class safe_iterator:

  public detail::iter_adaptor<safe_iterator<Iterator,Container>,Iterator>,

  public detail::safe_iterator_base

{

  typedef detail::iter_adaptor<safe_iterator,Iterator> super;

  typedef detail::safe_iterator_base                   safe_super;

public:

  typedef Container                                    container_type;

  typedef typename Iterator::reference                 reference;

  typedef typename Iterator::difference_type           difference_type;

  safe_iterator(){}

  explicit safe_iterator(safe_container<container_type>* cont_):

    safe_super(cont_){}

  template<typename T0>

  safe_iterator(const T0& t0,safe_container<container_type>* cont_):

    super(Iterator(t0)),safe_super(cont_){}

  template<typename T0,typename T1>

  safe_iterator(

    const T0& t0,const T1& t1,safe_container<container_type>* cont_):

    super(Iterator(t0,t1)),safe_super(cont_){}

  safe_iterator& operator=(const safe_iterator& x)

  {

    BOOST_MULTI_INDEX_CHECK_VALID_ITERATOR(x);

    this->base_reference()=x.base_reference();

    safe_super::operator=(x);

    return *this;

  }

  const container_type* owner()const

  {

    return

      static_cast<const container_type*>(

        static_cast<const safe_container<container_type>*>(

          this->safe_super::owner()));

  }

  /* get_node is not to be used by the user */

  typedef typename Iterator::node_type node_type;

  node_type* get_node()const{return this->base_reference().get_node();}

private:

  friend class boost::multi_index::detail::iter_adaptor_access;

  reference dereference()const

  {

    BOOST_MULTI_INDEX_CHECK_VALID_ITERATOR(*this);

    BOOST_MULTI_INDEX_CHECK_DEREFERENCEABLE_ITERATOR(*this);

    return *(this->base_reference());

  }

  bool equal(const safe_iterator& x)const

  {

    BOOST_MULTI_INDEX_CHECK_VALID_ITERATOR(*this);

    BOOST_MULTI_INDEX_CHECK_VALID_ITERATOR(x);

    BOOST_MULTI_INDEX_CHECK_SAME_OWNER(*this,x);

    return this->base_reference()==x.base_reference();

  }

  void increment()

  {

    BOOST_MULTI_INDEX_CHECK_VALID_ITERATOR(*this);

    BOOST_MULTI_INDEX_CHECK_INCREMENTABLE_ITERATOR(*this);

    ++(this->base_reference());

  }

  void decrement()

  {

    BOOST_MULTI_INDEX_CHECK_VALID_ITERATOR(*this);

    BOOST_MULTI_INDEX_CHECK_DECREMENTABLE_ITERATOR(*this);

    --(this->base_reference());

  }

  void advance(difference_type n)

  {

    BOOST_MULTI_INDEX_CHECK_VALID_ITERATOR(*this);

    BOOST_MULTI_INDEX_CHECK_IN_BOUNDS(*this,n);

    this->base_reference()+=n;

  }

  difference_type distance_to(const safe_iterator& x)const

  {

    BOOST_MULTI_INDEX_CHECK_VALID_ITERATOR(*this);

    BOOST_MULTI_INDEX_CHECK_VALID_ITERATOR(x);

    BOOST_MULTI_INDEX_CHECK_SAME_OWNER(*this,x);

    return x.base_reference()-this->base_reference();

  }

#if !defined(BOOST_MULTI_INDEX_DISABLE_SERIALIZATION)

  /* Serialization. Note that Iterator::save and Iterator:load

   * are assumed to be defined and public: at first sight it seems

   * like we could have resorted to the public serialization interface

   * for doing the forwarding to the adapted iterator class:

   *   ar<<base_reference();

   *   ar>>base_reference();

   * but this would cause incompatibilities if a saving

   * program is in safe mode and the loading program is not, or

   * viceversa --in safe mode, the archived iterator data is one layer

   * deeper, this is especially relevant with XML archives.

   * It'd be nice if Boost.Serialization provided some forwarding

   * facility for use by adaptor classes.

   */ 

  friend class boost::serialization::access;

  BOOST_SERIALIZATION_SPLIT_MEMBER()

  template<class Archive>

  void save(Archive& ar,const unsigned int version)const

  {

    BOOST_MULTI_INDEX_CHECK_VALID_ITERATOR(*this);

    this->base_reference().save(ar,version);

  }

  template<class Archive>

  void load(Archive& ar,const unsigned int version)

  {

    this->base_reference().load(ar,version);

    safe_super::uncheck();

  }

#endif

};

template<typename Container>

class safe_container:public detail::safe_container_base

{

  typedef detail::safe_container_base super;

public:

  void detach_dereferenceable_iterators()

  {

    typedef typename Container::iterator iterator;

    iterator end_=static_cast<Container*>(this)->end();

    iterator *prev_,*next_;

    for(

      prev_=static_cast<iterator*>(&this->header);

      (next_=static_cast<iterator*>(prev_->next))!=0;){

      if(*next_!=end_){

        prev_->next=next_->next;

        next_->cont=0;

      }

      else prev_=next_;

    }

  }

  void swap(safe_container<Container>& x)

  {

    super::swap(x);

  }

};

} /* namespace multi_index::safe_mode */

} /* namespace multi_index */

} /* namespace boost */

#endif /* BOOST_MULTI_INDEX_ENABLE_SAFE_MODE */

#endif