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// Copyright (C) 2007 Davis E. King (davis@dlib.net)
// License: Boost Software License See LICENSE.txt for the full license.
#undef DLIB_MULTITHREADED_OBJECT_EXTENSIOn_ABSTRACT_
#ifdef DLIB_MULTITHREADED_OBJECT_EXTENSIOn_ABSTRACT_
#include "threads_kernel_abstract.h"
namespace dlib
{
// ----------------------------------------------------------------------------------------
class multithreaded_object
{
/*!
INITIAL VALUE
- is_running() == false
- number_of_threads_alive() == 0
- number_of_threads_registered() == 0
WHAT THIS OBJECT REPRESENTS
This object represents a multithreaded object. It is similar to
the threaded_object except it allows you to have many threads in a
single object rather than just one. To use it you inherit from it
and register the member functions in your new class that you want
to run in their own threads by calling register_thread(). Then when
you call start() it will spawn all the registered functions
in their own threads.
!*/
public:
multithreaded_object (
);
/*!
ensures
- #*this is properly initialized
throws
- std::bad_alloc
- dlib::thread_error
the constructor may throw this exception if there is a problem
gathering resources to create threading objects.
!*/
virtual ~multithreaded_object (
) = 0;
/*!
requires
- number_of_threads_alive() == 0
(i.e. in the destructor for the object you derive from this one you
must wait for all the threads to end.)
ensures
- all resources allocated by *this have been freed.
!*/
void clear(
);
/*!
ensures
- #*this has its initial value
- blocks until all threads have terminated
throws
- std::bad_alloc or dlib::thread_error
if an exception is thrown then *this is unusable
until clear() is called and succeeds
!*/
bool is_running (
) const;
/*!
ensures
- if (number_of_threads_alive() > 0 && the threads are currently supposed to be executing) then
- returns true
- else
- returns false
!*/
unsigned long number_of_threads_alive (
) const;
/*!
ensures
- returns the number of threads that are currently alive (i.e.
the number of threads that have started but not yet terminated)
!*/
unsigned long number_of_threads_registered (
) const;
/*!
ensures
- returns the number of threads that have been registered by
calls to register_thread()
!*/
void wait (
) const;
/*!
requires
- is not called from one of this object's threads
ensures
- if (number_of_threads_alive() > 0) then
- blocks until all the threads in this object have terminated
(i.e. blocks until number_of_threads_alive() == 0)
!*/
void start (
);
/*!
ensures
- #number_of_threads_alive() == number_of_threads_registered()
- #is_running() == true
- #should_stop() == false
- all the threads registered are up and running.
throws
- std::bad_alloc or dlib::thread_error
If either of these exceptions are thrown then
#is_running() == false and should_stop() == true
!*/
void pause (
);
/*!
ensures
- #is_running() == false
!*/
void stop (
);
/*!
ensures
- #should_stop() == true
- #is_running() == false
!*/
protected:
template <
typename T
>
void register_thread (
T& object,
void (T::*thread)()
);
/*!
requires
- (object.*thread)() forms a valid function call
- the thread function does not throw
ensures
- registers the member function pointed to by thread as one of the threads
that runs when is_running() == true
- #number_of_threads_registered() == number_of_threads_registered() + 1
- if (is_running() == true)
- spawns this new member function in its own thread
- #number_of_threads_alive() += number_of_threads_alive() + 1
throws
- std::bad_alloc or dlib::thread_error
If either of these exceptions are thrown then
#is_running() == false and should_stop() == true
!*/
bool should_stop (
) const;
/*!
requires
- is only called from one of the registered threads in this object
ensures
- if (is_running() == false && should_stop() == false) then
- blocks until (#is_running() == true || #should_stop() == true)
- if (this thread is supposed to terminate) then
- returns true
- else
- returns false
!*/
private:
// restricted functions
multithreaded_object(multithreaded_object&); // copy constructor
multithreaded_object& operator=(multithreaded_object&); // assignment operator
};
// ----------------------------------------------------------------------------------------
}
#endif // DLIB_MULTITHREADED_OBJECT_EXTENSIOn_ABSTRACT_
|
