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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_TIMEOUT_KERNEl_ABSTRACT_
#ifdef DLIB_TIMEOUT_KERNEl_ABSTRACT_
#include "../threads.h"
namespace dlib
{
class timeout
{
/*!
WHAT THIS OBJECT REPRESENTS
This object provides a simple way to implement a timeout. An example will
make its use clear. Suppose we want to read from a socket but we want to
terminate the connection if the read takes longer than 10 seconds. This
could be accomplished as follows:
connection* con = a connection from somewhere;
{
// setup a timer that will call con->shutdown() in 10 seconds
timeout t(*con,&connection::shutdown,10000);
// Now call read on the connection. If this call to read() takes more
// than 10 seconds then the t timeout will trigger and shutdown the
// connection. If read completes in less than 10 seconds then the t
// object will be destructed on the next line due to the } and then the
// timeout won't trigger.
con->read(buf,100);
}
Alternatively, if you have a compiler capable of using C++11 lambda
functions, you can use a syntax like this:
{
timeout t([con](){ con->shutdown(); }, 10000);
con->read(buf,100);
}
More generally, you can use this with things other than sockets. For
example, the following statement will print "Hello world!" after 1000ms:
timeout t([](){ cout << "Hello world!" << endl; }, 1000);
THREAD SAFETY
All methods of this class are thread safe.
!*/
public:
template <
typename T
>
timeout (
T callback_function,
unsigned long ms_to_timeout
);
/*!
requires
- callback_function does not throw
ensures
- does not block.
- #*this is properly initialized
- if (this object isn't destructed in ms_to_timeout milliseconds) then
- callback_function() will be called in ms_to_timeout milliseconds.
throws
- std::bad_alloc
- dlib::thread_error
!*/
template <
typename T
>
timeout (
T& object,
void (T::*callback_function)(),
unsigned long ms_to_timeout
);
/*!
requires
- callback_function does not throw
ensures
- does not block.
- #*this is properly initialized
- if (this object isn't destructed in ms_to_timeout milliseconds) then
- (object.*callback_function)() will be called in ms_to_timeout
milliseconds.
throws
- std::bad_alloc
- dlib::thread_error
!*/
template <
typename T,
typename U
>
timeout (
T& object,
void (T::*callback_function)(U callback_function_argument),
unsigned long ms_to_timeout,
U callback_function_argument
);
/*!
requires
- callback_function does not throw
ensures
- does not block.
- #*this is properly initialized
- if (this object isn't destructed in ms_to_timeout milliseconds) then
- (object.*callback_function)(callback_function_argument) will be
called in ms_to_timeout milliseconds.
throws
- std::bad_alloc
- dlib::thread_error
!*/
template <
typename T
>
timeout (
T& object,
int (T::*callback_function)(),
unsigned long ms_to_timeout
);
/*!
requires
- callback_function does not throw
ensures
- does not block.
- #*this is properly initialized
- if (this object isn't destructed in ms_to_timeout milliseconds) then
- (object.*callback_function)() will be called in ms_to_timeout
milliseconds.
throws
- std::bad_alloc
- dlib::thread_error
!*/
template <
typename T,
typename U
>
timeout (
T& object,
int (T::*callback_function)(U callback_function_argument),
unsigned long ms_to_timeout,
U callback_function_argument
);
/*!
requires
- callback_function does not throw
ensures
- does not block.
- #*this is properly initialized
- if (this object isn't destructed in ms_to_timeout milliseconds) then
- (object.*callback_function)(callback_function_argument) will be
called in ms_to_timeout milliseconds.
throws
- std::bad_alloc
- dlib::thread_error
!*/
virtual ~timeout (
);
/*!
requires
- is not called from inside the callback_function given to the
constructor.
ensures
- any resources associated with *this have been released
- if (the callback_function hasn't been called yet) then
- the callback_function specified in the constructor will not be called
!*/
private:
// restricted functions
timeout(const timeout&); // copy constructor
timeout& operator=(const timeout&); // assignment operator
};
}
#endif // DLIB_TIMEOUT_KERNEl_ABSTRACT_
|
