blob: 379f8e9d820a7fa10d563de3a49c0dcd47eacdc6 [file] [log] [blame]
//
// sp_collector.cpp
//
// Copyright (c) 2002, 2003 Peter Dimov
//
// 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)
//
#if defined(BOOST_SP_ENABLE_DEBUG_HOOKS)
#include <boost/assert.hpp>
#include <boost/shared_ptr.hpp>
#include <boost/detail/lightweight_mutex.hpp>
#include <cstdlib>
#include <map>
#include <deque>
#include <iostream>
typedef std::map< void const *, std::pair<void *, size_t> > map_type;
static map_type & get_map()
{
static map_type m;
return m;
}
typedef ndnboost::detail::lightweight_mutex mutex_type;
static mutex_type & get_mutex()
{
static mutex_type m;
return m;
}
static void * init_mutex_before_main = &get_mutex();
namespace
{
class X;
struct count_layout
{
ndnboost::detail::sp_counted_base * pi;
int id;
};
struct shared_ptr_layout
{
X * px;
count_layout pn;
};
}
// assume 4 byte alignment for pointers when scanning
size_t const pointer_align = 4;
typedef std::map<void const *, long> map2_type;
static void scan_and_count(void const * area, size_t size, map_type const & m, map2_type & m2)
{
unsigned char const * p = static_cast<unsigned char const *>(area);
for(size_t n = 0; n + sizeof(shared_ptr_layout) <= size; p += pointer_align, n += pointer_align)
{
shared_ptr_layout const * q = reinterpret_cast<shared_ptr_layout const *>(p);
if(q->pn.id == ndnboost::detail::shared_count_id && q->pn.pi != 0 && m.count(q->pn.pi) != 0)
{
++m2[q->pn.pi];
}
}
}
typedef std::deque<void const *> open_type;
static void scan_and_mark(void const * area, size_t size, map2_type & m2, open_type & open)
{
unsigned char const * p = static_cast<unsigned char const *>(area);
for(size_t n = 0; n + sizeof(shared_ptr_layout) <= size; p += pointer_align, n += pointer_align)
{
shared_ptr_layout const * q = reinterpret_cast<shared_ptr_layout const *>(p);
if(q->pn.id == ndnboost::detail::shared_count_id && q->pn.pi != 0 && m2.count(q->pn.pi) != 0)
{
open.push_back(q->pn.pi);
m2.erase(q->pn.pi);
}
}
}
static void find_unreachable_objects_impl(map_type const & m, map2_type & m2)
{
// scan objects for shared_ptr members, compute internal counts
{
std::cout << "... " << m.size() << " objects in m.\n";
for(map_type::const_iterator i = m.begin(); i != m.end(); ++i)
{
ndnboost::detail::sp_counted_base const * p = static_cast<ndnboost::detail::sp_counted_base const *>(i->first);
BOOST_ASSERT(p->use_count() != 0); // there should be no inactive counts in the map
m2[ i->first ];
scan_and_count(i->second.first, i->second.second, m, m2);
}
std::cout << "... " << m2.size() << " objects in m2.\n";
}
// mark reachable objects
{
open_type open;
for(map2_type::iterator i = m2.begin(); i != m2.end(); ++i)
{
ndnboost::detail::sp_counted_base const * p = static_cast<ndnboost::detail::sp_counted_base const *>(i->first);
if(p->use_count() != i->second) open.push_back(p);
}
std::cout << "... " << open.size() << " objects in open.\n";
for(open_type::iterator j = open.begin(); j != open.end(); ++j)
{
m2.erase(*j);
}
while(!open.empty())
{
void const * p = open.front();
open.pop_front();
map_type::const_iterator i = m.find(p);
BOOST_ASSERT(i != m.end());
scan_and_mark(i->second.first, i->second.second, m2, open);
}
}
// m2 now contains the unreachable objects
}
std::size_t find_unreachable_objects(bool report)
{
map2_type m2;
#ifdef BOOST_HAS_THREADS
// This will work without the #ifdef, but some compilers warn
// that lock is not referenced
mutex_type::scoped_lock lock(get_mutex());
#endif
map_type const & m = get_map();
find_unreachable_objects_impl(m, m2);
if(report)
{
for(map2_type::iterator j = m2.begin(); j != m2.end(); ++j)
{
map_type::const_iterator i = m.find(j->first);
BOOST_ASSERT(i != m.end());
std::cout << "Unreachable object at " << i->second.first << ", " << i->second.second << " bytes long.\n";
}
}
return m2.size();
}
typedef std::deque< ndnboost::shared_ptr<X> > free_list_type;
static void scan_and_free(void * area, size_t size, map2_type const & m2, free_list_type & free)
{
unsigned char * p = static_cast<unsigned char *>(area);
for(size_t n = 0; n + sizeof(shared_ptr_layout) <= size; p += pointer_align, n += pointer_align)
{
shared_ptr_layout * q = reinterpret_cast<shared_ptr_layout *>(p);
if(q->pn.id == ndnboost::detail::shared_count_id && q->pn.pi != 0 && m2.count(q->pn.pi) != 0 && q->px != 0)
{
ndnboost::shared_ptr<X> * ppx = reinterpret_cast< ndnboost::shared_ptr<X> * >(p);
free.push_back(*ppx);
ppx->reset();
}
}
}
void free_unreachable_objects()
{
free_list_type free;
{
map2_type m2;
#ifdef BOOST_HAS_THREADS
mutex_type::scoped_lock lock(get_mutex());
#endif
map_type const & m = get_map();
find_unreachable_objects_impl(m, m2);
for(map2_type::iterator j = m2.begin(); j != m2.end(); ++j)
{
map_type::const_iterator i = m.find(j->first);
BOOST_ASSERT(i != m.end());
scan_and_free(i->second.first, i->second.second, m2, free);
}
}
std::cout << "... about to free " << free.size() << " objects.\n";
}
// debug hooks
namespace ndnboost
{
void sp_scalar_constructor_hook(void *)
{
}
void sp_scalar_constructor_hook(void * px, std::size_t size, void * pn)
{
#ifdef BOOST_HAS_THREADS
mutex_type::scoped_lock lock(get_mutex());
#endif
get_map()[pn] = std::make_pair(px, size);
}
void sp_scalar_destructor_hook(void *)
{
}
void sp_scalar_destructor_hook(void *, std::size_t, void * pn)
{
#ifdef BOOST_HAS_THREADS
mutex_type::scoped_lock lock(get_mutex());
#endif
get_map().erase(pn);
}
void sp_array_constructor_hook(void *)
{
}
void sp_array_destructor_hook(void *)
{
}
} // namespace ndnboost
#endif // defined(BOOST_SP_ENABLE_DEBUG_HOOKS)