boost/multi_index/detail/safe_mode.hpp
/* Copyright 2003-2013 Joaquin M Lopez Munoz.
* 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()){
{
#if defined(BOOST_HAS_THREADS)
boost::detail::lightweight_mutex::scoped_lock lock(it.cont->mutex);
#endif
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