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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_THREADED_OBJECT_EXTENSIOn_ABSTRACT_
#ifdef DLIB_THREADED_OBJECT_EXTENSIOn_ABSTRACT_
#include "threads_kernel_abstract.h"
namespace dlib
{
// ----------------------------------------------------------------------------------------
class threaded_object
{
/*!
INITIAL VALUE
- is_running() == false
- is_alive() == false
- should_respawn() == false
WHAT THIS OBJECT REPRESENTS
This object represents a simple threaded object. To use it you inherit
from it and define the thread() function. Then when you call start()
it will spawn a thread that calls this->thread().
!*/
public:
threaded_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 ~threaded_object (
);
/*!
requires
- is_alive() == false
(i.e. in the destructor for the object you derive from this one you
must wait for this->thread() to end.)
ensures
- all resources allocated by *this have been freed.
!*/
bool is_running (
) const;
/*!
requires
- is not called from this->thread()
ensures
- if (is_alive() && this->thread() is currently supposed to be executing) then
- returns true
- else
- returns false
!*/
bool is_alive (
) const;
/*!
requires
- is not called from this->thread()
ensures
- if (this->thread() has been called by some thread and has yet to terminate) then
- returns true
- else
- returns false
!*/
void wait (
) const;
/*!
requires
- is not called from this->thread()
ensures
- if (is_alive() == true) then
- blocks until this->thread() terminates
!*/
void start (
);
/*!
requires
- is not called from this->thread()
ensures
- #is_alive() == true
- #is_running() == true
- #should_stop() == false
throws
- std::bad_alloc or dlib::thread_error
If either of these exceptions are thrown then
#is_alive() == false and #is_running() == false
!*/
void set_respawn (
);
/*!
requires
- is not called from this->thread()
ensures
- #should_respawn() == true
!*/
bool should_respawn (
) const;
/*!
requires
- is not called from this->thread()
ensures
- returns true if the thread will automatically restart upon termination and
false otherwise. Note that every time a thread starts it sets should_respawn()
back to false. Therefore, a single call to set_respawn() can cause at most
one respawn to occur.
!*/
void restart (
);
/*!
requires
- is not called from this->thread()
ensures
- This function atomically executes set_respawn() and start(). The precise meaning of this
is defined below.
- if (is_alive()) then
- #should_respawn() == true
- else
- #should_respawn() == false
- #is_alive() == true
- #is_running() == true
- #should_stop() == false
throws
- std::bad_alloc or dlib::thread_error
If either of these exceptions are thrown then
#is_alive() == false and #is_running() == false
!*/
void pause (
);
/*!
requires
- is not called from this->thread()
ensures
- #is_running() == false
!*/
void stop (
);
/*!
requires
- is not called from this->thread()
ensures
- #should_stop() == true
- #is_running() == false
- #should_respawn() == false
!*/
protected:
bool should_stop (
) const;
/*!
requires
- is only called from the thread that executes this->thread()
ensures
- calls to this function block until (#is_running() == true || #should_stop() == true)
- if (this thread is supposed to terminate) then
- returns true
- else
- returns false
!*/
private:
virtual void thread (
) = 0;
/*!
requires
- is executed in its own thread
- is only executed in one thread at a time
throws
- does not throw any exceptions
!*/
// restricted functions
threaded_object(threaded_object&); // copy constructor
threaded_object& operator=(threaded_object&); // assignment operator
};
// ----------------------------------------------------------------------------------------
}
#endif // DLIB_THREADED_OBJECT_EXTENSIOn_ABSTRACT_
|
