153 lines
4.8 KiB
Plaintext
153 lines
4.8 KiB
Plaintext
#ifndef BOOST_SERIALIZATION_SINGLETON_HPP
|
|
#define BOOST_SERIALIZATION_SINGLETON_HPP
|
|
|
|
/////////1/////////2///////// 3/////////4/////////5/////////6/////////7/////////8
|
|
// singleton.hpp
|
|
//
|
|
// Copyright David Abrahams 2006. Original version
|
|
//
|
|
// Copyright Robert Ramey 2007. Changes made to permit
|
|
// application throughout the serialization library.
|
|
//
|
|
// 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)
|
|
//
|
|
// The intention here is to define a template which will convert
|
|
// any class into a singleton with the following features:
|
|
//
|
|
// a) initialized before first use.
|
|
// b) thread-safe for const access to the class
|
|
// c) non-locking
|
|
//
|
|
// In order to do this,
|
|
// a) Initialize dynamically when used.
|
|
// b) Require that all singletons be initialized before main
|
|
// is called or any entry point into the shared library is invoked.
|
|
// This guarentees no race condition for initialization.
|
|
// In debug mode, we assert that no non-const functions are called
|
|
// after main is invoked.
|
|
//
|
|
|
|
// MS compatible compilers support #pragma once
|
|
#if defined(_MSC_VER)
|
|
# pragma once
|
|
#endif
|
|
|
|
#include <boost/assert.hpp>
|
|
#include <boost/config.hpp>
|
|
#include <boost/noncopyable.hpp>
|
|
#include <boost/serialization/force_include.hpp>
|
|
|
|
#include <boost/archive/detail/auto_link_archive.hpp>
|
|
#include <boost/serialization/config.hpp>
|
|
#include <boost/archive/detail/abi_prefix.hpp> // must be the last header
|
|
|
|
#ifdef BOOST_MSVC
|
|
# pragma warning(push)
|
|
# pragma warning(disable : 4511 4512)
|
|
#endif
|
|
|
|
namespace boost {
|
|
namespace serialization {
|
|
|
|
//////////////////////////////////////////////////////////////////////
|
|
// Provides a dynamically-initialized (singleton) instance of T in a
|
|
// way that avoids LNK1179 on vc6. See http://tinyurl.com/ljdp8 or
|
|
// http://lists.boost.org/Archives/boost/2006/05/105286.php for
|
|
// details.
|
|
//
|
|
|
|
// singletons created by this code are guarenteed to be unique
|
|
// within the executable or shared library which creates them.
|
|
// This is sufficient and in fact ideal for the serialization library.
|
|
// The singleton is created when the module is loaded and destroyed
|
|
// when the module is unloaded.
|
|
|
|
// This base class has two functions.
|
|
|
|
// First it provides a module handle for each singleton indicating
|
|
// the executable or shared library in which it was created. This
|
|
// turns out to be necessary and sufficient to implement the tables
|
|
// used by serialization library.
|
|
|
|
// Second, it provides a mechanism to detect when a non-const function
|
|
// is called after initialization.
|
|
|
|
// make a singleton to lock/unlock all singletons for alteration.
|
|
// The intent is that all singletons created/used by this code
|
|
// are to be initialized before main is called. A test program
|
|
// can lock all the singletons when main is entereed. This any
|
|
// attempt to retieve a mutable instances while locked will
|
|
// generate a assertion if compiled for debug.
|
|
|
|
class BOOST_SYMBOL_VISIBLE singleton_module :
|
|
public boost::noncopyable
|
|
{
|
|
private:
|
|
static bool & get_lock();
|
|
public:
|
|
BOOST_SERIALIZATION_DECL static void lock();
|
|
BOOST_SERIALIZATION_DECL static void unlock();
|
|
BOOST_SERIALIZATION_DECL static bool is_locked();
|
|
};
|
|
|
|
#include <boost/archive/detail/abi_suffix.hpp> // pops abi_suffix.hpp pragmas
|
|
|
|
namespace detail {
|
|
|
|
template<class T>
|
|
class singleton_wrapper : public T
|
|
{
|
|
public:
|
|
static bool m_is_destroyed;
|
|
~singleton_wrapper(){
|
|
m_is_destroyed = true;
|
|
}
|
|
};
|
|
|
|
template<class T>
|
|
bool detail::singleton_wrapper< T >::m_is_destroyed = false;
|
|
|
|
} // detail
|
|
|
|
template <class T>
|
|
class singleton : public singleton_module
|
|
{
|
|
private:
|
|
BOOST_DLLEXPORT static T & instance;
|
|
// include this to provoke instantiation at pre-execution time
|
|
static void use(T const *) {}
|
|
BOOST_DLLEXPORT static T & get_instance() {
|
|
static detail::singleton_wrapper< T > t;
|
|
// refer to instance, causing it to be instantiated (and
|
|
// initialized at startup on working compilers)
|
|
BOOST_ASSERT(! detail::singleton_wrapper< T >::m_is_destroyed);
|
|
use(& instance);
|
|
return static_cast<T &>(t);
|
|
}
|
|
public:
|
|
BOOST_DLLEXPORT static T & get_mutable_instance(){
|
|
BOOST_ASSERT(! is_locked());
|
|
return get_instance();
|
|
}
|
|
BOOST_DLLEXPORT static const T & get_const_instance(){
|
|
return get_instance();
|
|
}
|
|
BOOST_DLLEXPORT static bool is_destroyed(){
|
|
return detail::singleton_wrapper< T >::m_is_destroyed;
|
|
}
|
|
};
|
|
|
|
template<class T>
|
|
BOOST_DLLEXPORT T & singleton< T >::instance = singleton< T >::get_instance();
|
|
|
|
} // namespace serialization
|
|
} // namespace boost
|
|
|
|
#ifdef BOOST_MSVC
|
|
#pragma warning(pop)
|
|
#endif
|
|
|
|
#endif // BOOST_SERIALIZATION_SINGLETON_HPP
|