我需要创建一个boost :: statechart :: asynchronous_state_machine，我需要能够＆＃34; destroy＆＃34;在外面。 我在文档中发现我应该调用destroy_processor并终止它。问题是这些方法只是在机器事件队列中插入一个事件，因此，如果我删除了fifo_scheduler＆lt;＆gt;在处理这些事件之前，会引发错误...（参见下面的示例）
问题是......我怎么知道asynchronous_state_machine何时终止＆＃34; ＆＃34;删除＆＃34;是安全的。 fifo_scheduler＆lt;＆gt; ？
#include <boost/statechart/event.hpp>
#include <boost/statechart/state.hpp>
#include <boost/statechart/custom_reaction.hpp>
#include <boost/statechart/asynchronous_state_machine.hpp>
#include <boost/statechart/fifo_scheduler.hpp>
#include <boost/intrusive_ptr.hpp>
#include <boost/asio/io_service.hpp>
#include <boost/thread/thread.hpp>
#include <iostream>
namespace sc = boost::statechart;
// States
struct Stop;
struct Running;
struct Playing;
struct Paused;
// Events
struct EvPlay : public sc::event<EvPlay>{};
struct EvStop : public sc::event<EvStop>{};
struct EvPause : public sc::event<EvPause>{};
// State machine and states definition
struct MyMachine : public sc::asynchronous_state_machine<MyMachine,Stop>
{
public:
MyMachine (my_context ctx, const unsigned int& ai_id)
: my_base(ctx)
, m_id(ai_id)
{
std::cout << "th["<< boost::this_thread::get_id() << "]"
<< "MyMachine["<< m_id << "]: Constructor "
<< std::endl;
}
~MyMachine (void)
{
std::cout << "th["<< boost::this_thread::get_id() << "]"
<< "MyMachine["<< m_id << "]: Destructor "
<< std::endl;
}
unsigned int id(void)const
{
return m_id;
}
private:
unsigned int m_id;
};
struct Stop : sc::state<Stop,MyMachine>
{
public:
typedef sc::custom_reaction<EvPlay> reactions;
Stop(my_context ctx)
: my_base(ctx)
, m_id(context<MyMachine>().id())
{
std::cout << "th["<< boost::this_thread::get_id() << "]"
<< "OnEntry["<< m_id << "]: Stop "
<< std::endl;
}
~Stop(void)
{
std::cout << "th["<< boost::this_thread::get_id() << "]"
<< "OnExit["<< m_id << "]: Stop "
<< std::endl;
}
sc::result react(const EvPlay&)
{
std::cout << "th["<< boost::this_thread::get_id() << "]"
<< "Stop::Event["<< m_id << "]: EvPlay "
<< std::endl;
return transit<Running>();
}
private:
unsigned int m_id;
};
struct Running : sc::state <Running, MyMachine, Playing>
{
public:
typedef sc::custom_reaction<EvStop> reactions;
Running(my_context ctx)
: my_base(ctx)
, m_id(context<MyMachine>().id())
{
std::cout << "th["<< boost::this_thread::get_id() << "]"
<< "OnEntry["<< m_id << "]: Running "
<< std::endl;
}
~Running(void)
{
std::cout << "th["<< boost::this_thread::get_id() << "]"
<< "OnExit["<< m_id << "]: Running "
<< std::endl;
}
sc::result react(const EvStop&)
{
std::cout << "th["<< boost::this_thread::get_id() << "]"
<< "Running::Event["<< m_id << "]: EvStop "
<< std::endl;
return transit<Stop>();
}
private:
unsigned int m_id;
};
struct Playing : sc::state<Playing, Running>
{
public:
typedef sc::custom_reaction<EvPause> reactions;
Playing(my_context ctx)
: my_base(ctx)
, m_id(context<MyMachine>().id())
{
std::cout << "th["<< boost::this_thread::get_id() << "]"
<< "OnEntry["<< m_id << "]: Playing "
<< std::endl;
}
~Playing(void)
{
std::cout << "th["<< boost::this_thread::get_id() << "]"
<< "OnExit["<< m_id << "]: Playing "
<< std::endl;
}
sc::result react(const EvPause&)
{
std::cout << "th["<< boost::this_thread::get_id() << "]"
<< "Playing::Event["<< m_id << "]: EvPause "
<< std::endl;
return transit<Paused>();
}
private:
unsigned int m_id;
};
struct Paused : sc::state<Paused, Running>
{
public:
typedef sc::custom_reaction<EvPause> reactions;
Paused(my_context ctx)
: my_base(ctx)
, m_id(context<MyMachine>().id())
{
std::cout << "th["<< boost::this_thread::get_id() << "]"
<< "OnEntry["<< m_id << "]: Paused "
<< std::endl;
}
~Paused(void)
{
std::cout << "th["<< boost::this_thread::get_id() << "]"
<< "OnExit["<< m_id << "]: Paused "
<< std::endl;
}
sc::result react(const EvPause&)
{
std::cout << "th["<< boost::this_thread::get_id() << "]"
<< "Paused::Event["<< m_id << "]: EvPause "
<< std::endl;
return transit<Playing>();
}
private:
unsigned int m_id;
};
// ---------------------------------------------------------------------------
int main(void)
{
// create threadpool and ioservice
boost::thread_group threadPool;
boost::asio::io_service ioService;
// create work for ioservice
boost::asio::io_service::work* work (new boost::asio::io_service::work(ioService));
// create threads
threadPool.create_thread(boost::bind(&boost::asio::io_service::run, &ioService));
// create machines
sc::fifo_scheduler<>* sch1(new sc::fifo_scheduler<>(true));
sc::fifo_scheduler<>::processor_handle handle1 (sch1->create_processor<MyMachine>(1));
//initiate machines
sch1->initiate_processor(handle1);
ioService.post(boost::bind(&sc::fifo_scheduler<>::operator(),sch1,0));
boost::this_thread::sleep(boost::posix_time::milliseconds(1000));
std::cout << "main_th["<< boost::this_thread::get_id() << "]:" << "destroying ... " << std::endl;
sch1->destroy_processor(handle1);
sch1->terminate();
std::cout << "main_th["<< boost::this_thread::get_id() << "]:" << " ... destroyed " << std::endl;
// some time to process the events ( not a solution ) ...
// comment this line to get the error.
boost::this_thread::sleep(boost::posix_time::milliseconds(5000));
std::cout << "main_th["<< boost::this_thread::get_id() << "]:" << "deleting ... "<< std::endl;
delete sch1;
sch1 = 0;
std::cout << "main_th["<< boost::this_thread::get_id() << "]:" << " ... deleted"<< std::endl;
// kill work to exit
delete work;
work = 0;
//wait for all threads to exit
threadPool.join_all();
return 0;
}
答案 0 :(得分：0)
您可以通过 terminate() 函数检查 fifo_scheduler 对象内部状态机的状态。
在你的代码中你可以做到
if(sch1->terminated()) {
// do something for the state machine has terminated
// destroy_processor() and terminate() or something else
}
您将使用 do 或 for cycle 来处理这种原因。