peerplays-fc/include/fc/thread.hpp

#pragma once
#include <fc/task.hpp>
#include <fc/vector.hpp>
#include <fc/string.hpp>

namespace fc {
  class time_point;
  class microseconds;

  class thread {
    public:
      thread( const char* name = "" );
      thread( thread&& m );
      thread& operator=(thread&& t );

      /**
       *  Returns the current thread.
       */
      static thread& current();

     
      /**
       *  @brief returns the name given by @ref set_name() for this thread
       */
      const string& name()const;

      /**
       *  @brief associates a name with this thread.
       */
      void        set_name( const string& n );
       
      /**
       *  @brief print debug info about the state of every context / promise.
       *
       *  This method is helpful to figure out where your program is 'hung' by listing
       *  every async operation (context) and what it is blocked on (future).  
       *
       *  @note debug info is more useful if you provide a description for your
       *  async tasks and promises.
       */
      void    debug( const fc::string& d );
     
     
      /**
       *  Calls function <code>f</code> in this thread and returns a future<T> that can
       *  be used to wait on the result.  
       *
       *  @param f the operation to perform
       *  @param prio the priority relative to other tasks
       */
      template<typename Functor>
      auto async( Functor&& f, const char* desc ="", priority prio = priority()) -> fc::future<decltype(f())> {
         typedef decltype(f()) Result;
         typedef typename fc::deduce<Functor>::type FunctorType;
         fc::task<Result,sizeof(FunctorType)>* tsk = 
              new fc::task<Result,sizeof(FunctorType)>( fc::forward<Functor>(f) );
         fc::future<Result> r(fc::shared_ptr< fc::promise<Result> >(tsk,true) );
         async_task(tsk,prio,desc);
         return r;
      }
      void poke();
     
     
      /**
       *  Calls function <code>f</code> in this thread and returns a future<T> that can
       *  be used to wait on the result.
       *
       *  @param f the method to be called
       *  @param prio the priority of this method relative to others
       *  @param when determines when this call will happen, as soon as 
       *        possible after <code>when</code>
       */
      template<typename Functor>
      auto schedule( Functor&& f, const fc::time_point& when, 
                     const char* desc = "", priority prio = priority()) -> fc::future<decltype(f())> {
         typedef decltype(f()) Result;
         fc::task<Result,sizeof(Functor)>* tsk = 
              new fc::task<Result,sizeof(Functor)>( fc::forward<Functor>(f) );
         fc::future<Result> r(fc::shared_ptr< fc::promise<Result> >(tsk,true) );
         async_task(tsk,prio,when,desc);
         return r;
      }
     
      /**
       *  This method will cancel all pending tasks causing them to throw cmt::error::thread_quit.
       *
       *  If the <i>current</i> thread is not <code>this</code> thread, then the <i>current</i> thread will
       *  wait for <code>this</code> thread to exit.
       *
       *  This is a blocking wait via <code>boost::thread::join</code>
       *  and other tasks in the <i>current</i> thread will not run while 
       *  waiting for <code>this</code> thread to quit.
       *
       *  @todo make quit non-blocking of the calling thread by eliminating the call to <code>boost::thread::join</code>
       */
      void quit();
     
      /**
       *  @return true unless quit() has been called.
       */
      bool is_running()const;
      bool is_current()const;
     
      priority current_priority()const;
      ~thread();

       template<typename T1, typename T2>
       int wait_any( const fc::future<T1>& f1, const fc::future<T2>& f2, const microseconds& timeout_us = microseconds::max()) {
          fc::vector<fc::promise_base::ptr> proms(2);
          proms[0] = fc::static_pointer_cast<fc::promise_base>(f1.m_prom);
          proms[1] = fc::static_pointer_cast<fc::promise_base>(f2.m_prom);
          return wait_any_until(fc::move(proms), fc::time_point::now()+timeout_us );
       }
    private:
      thread( class thread_d* );
      friend class promise_base;
      friend class thread_d;
      friend class mutex;
      friend void yield();
      friend void usleep(const microseconds&);
      friend void sleep_until(const time_point&);
      friend void exec();
      friend int wait_any( fc::vector<promise_base::ptr>&& v, const microseconds& );
      friend int wait_any_until( fc::vector<promise_base::ptr>&& v, const time_point& tp );
      void wait_until( promise_base::ptr && v, const time_point& tp );
      void notify( const promise_base::ptr& v );

      void yield(bool reschedule=true);
      void sleep_until( const time_point& t );
      void  exec();
      int  wait_any_until( fc::vector<promise_base::ptr>&& v, const time_point& );

      void async_task( task_base* t, const priority& p, const char* desc );
      void async_task( task_base* t, const priority& p, const time_point& tp, const char* desc );
      class thread_d* my;

  };

  /** 
   *  Yields to other ready tasks before returning.
   */
   void yield();

   /** 
    *  Yields to other ready tasks for u microseconds.
    */
   void usleep( const microseconds& u );

   /** 
    *  Yields until the specified time in the future.
    */
   void sleep_until( const time_point& tp );

   /**
    *  Enters the main loop processing tasks until quit() is called.
    */
   void  exec();

   /**
    * Wait until either f1 or f2 is ready.
    *
    * @return 0 if f1 is ready, 1 if f2 is ready or throw on error.
    */
   template<typename T1, typename T2>
   int wait_any( const fc::future<T1>& f1, const fc::future<T2>& f2, const microseconds timeout_us = microseconds::max()) {
      return fc::thread::current().wait_any(f1,f2,timeout_us);
   }
   int wait_any( fc::vector<promise_base::ptr>&& v, const microseconds& timeout_us = microseconds::max() );
   int wait_any_until( fc::vector<promise_base::ptr>&& v, const time_point& tp );

   template<typename Functor>
   auto async( Functor&& f, const char* desc ="", priority prio = priority()) -> fc::future<decltype(f())> {
      return fc::thread::current().async( fc::forward<Functor>(f), desc, prio );
   }
}