*
* @section Introduction
*
- * The libevent API provides a mechanism to execute a callback function when a
- * specific event occurs on a file descriptor or after a timeout has been
- * reached. Furthermore, libevent also support callbacks due to signals or
- * regular timeouts.
- *
- * libevent is meant to replace the event loop found in event driven network
- * servers. An application just needs to call dispatcher::dispatch() and then
- * add or remove events dynamically without having to change the event loop.
- *
- * Currently, libevent supports /dev/poll, kqueue(2), select(2), poll(2) and
- * epoll(4). It also has experimental support for real-time signals. The
- * internal event mechanism is completely independent of the exposed event API,
- * and a simple update of libevent can provide new functionality without having
- * to redesign the applications. As a result, Libevent allows for portable
- * application development and provides the most scalable event notification
- * mechanism available on an operating system. Libevent should compile on Linux,
- * *BSD, Mac OS X, Solaris and Windows.
- *
- * This is a simple, direct, one-header inline C++ wrapper for libevent. Yes,
- * it's just one header file, so if you want to use it you can just copy the
- * file to your project and you are set.
- *
- * It's designed to be as close to use to libevent (without compromising modern
- * C++ programming techniques) and efficiency (since all implementation is
- * trivial and inline, theoretically, it imposes no overhead at all).
- *
- * Please, visit the <a href="http://www.llucax.com.ar/~luca/eventxx/">eventxx
- * website</a> for the latest documentation.
- *
- * You can always <a href="http://www.lluca.com.ar/~lucax/repos/eventxx/">get
- * the most up to date sources</a> from the
- * <a href="http://www.darcs.net/">darcs</a>.
+ * @libevent is a popular API that provides a mechanism to execute a callback
+ * function when a specific event occurs on a file descriptor or after a
+ * timeout has been reached. Furthermore, @libevent also support callbacks due
+ * to signals or regular timeouts.
+ *
+ * @eventxx is a simple, direct, one-header inline C++ wrapper for @libevent.
+ * Yes, it's just one header file, so if you want to use it you can just copy
+ * the file to your project and you are set (well, you'll need to link to
+ * @libevent too ;). I know @eventxx will work with @libevent 1.1 and 1.2 if you
+ * use the @c event_base_free() fix (see \ref Status section for more details).
+ *
+ * It's designed to be as close to use to @libevent (without compromising
+ * modern C++ programming techniques) and efficient (since all implementation
+ * is trivial and inline, theoretically, it imposes no overhead at all) as
+ * possible.
+ *
+ * Please, visit the @eventxx website for the latest version of this
+ * documentation.
+ *
+ * You can always get the <a
+ * href="http://www.llucax.com.ar/~luca/eventxx/releases/eventxx.tar.gz">current
+ * release</a> from the
+ * <a href="http://www.llucax.com.ar/~luca/eventxx/releases/">release
+ * directory</a> or grab the
+ * <a href="http://www.llucax.com.ar/~luca/repos/eventxx/">most up to date
+ * sources</a> from the <a href="http://www.darcs.net/">darcs</a> repository.
*
* You can also take a look the the <a
* href="http://auriga.wearlab.de/~alb/darcsweb/">darcsweb</a> interface to see
* the <a href="http://www.llucax.com.ar/~luca/repos/darcsweb/?r=eventxx">latest
- * changes online</a>.
+ * changes online</a> or subscribe to its
+ * <a href="http://www.llucax.com.ar/~luca/repos/darcsweb/?r=eventxx;a=rss">RSS
+ * feed</a> to follow the development.
*
*
* @section Usage
*
- * This wrapper was designed to be used just like libevent, but with C++ style
- * syntax sugar (or poisson, depends on your point of view ;) and goodies. The
- * main difference to libevent is you allways have to instance a
+ * You probably should read @libevent documentation to get started or at least
+ * just for reference, although @eventxx is pretty simple so you can jump right
+ * into the \ref Example section (or the example list) and write a working
+ * program without much trouble.
+ *
+ * This wrapper was designed to be used just like @libevent, but with C++ style
+ * syntax sugar (or poison, depends on your point of view ;) and goodies. The
+ * main difference to libevent is you always have to instance a
* eventxx::dispatcher to get an event loop. There is no implicit global event
* loop. This adds just an extra line of code for single threaded applications
- * and makes things much more simple. See eventxx::dispatcher documentation for
- * more details.
+ * and makes things much more simpler, so I hope nobody complains about it ;).
+ * See eventxx::dispatcher documentation for more details.
*
- * You can use use the same plain functions callbacks or the other kind of
- * function objects (see @link events @endlink section for details on event
+ * You can use use the same plain functions callbacks @libevent use or the other
+ * kind of function objects (see @ref events section for details on event
* types).
*
- * eventxx uses @link exceptions @endlink to report errors. All functions has
- * exception specifications, so it's easy to find out what to expect. See
- * exceptions section for more detail.
+ * @eventxx uses @ref exceptions to report errors. All functions have exception
+ * specifications, so it's easy to find out what to expect. See @ref exceptions
+ * section for more detail.
*
- * A timespec abstraction is provided in eventxx::time for convenient argument
- * passing. Even more, it's a timespec itself, with some convenient methods for
- * accessing the timespec attributes in a more C++ way. And even more, eventxx
- * is such a direct mapping that all eventxx::event's are libevent event structs
- * too, so theoretically you can pass a eventxx::event to libevent C functions
- * without much trouble. eventxx::dispatcher is the only class that is not
- * derived from libevent struct (event_base) because this struct it's not
- * defined on the libevent header (just declared).
+ * A @c timespec abstraction is provided as eventxx::time for convenient
+ * argument passing. Even more, it's a @c timespec itself, with some convenient
+ * methods for accessing the attributes with pritier names. And even more,
+ * @eventxx is such a direct mapping that all eventxx::event's are @libevent
+ * event structs too, so theoretically you can pass a eventxx::event to
+ * @libevent C functions without much trouble. eventxx::dispatcher is the only
+ * class that is not derived from @libevent struct (@c event_base) because this
+ * struct it's not defined on the libevent header (just declared).
*
* Maybe you shouldn't know this implementation details to keep the abstraction,
* but this is a basic design goal of this wrapper so there is not much chance
- * that this changes in the future (but use this knowledge with care, you are
- * warned ;).
+ * that this changes in the future (but use this knowledge with care, you have
+ * been warned ;).
+ *
*
* @section Example
*
* eventxx::dispatcher& d;
* int i;
* handler(eventxx::dispatcher& d): d(d), i(0) {}
- * void operator() (int signum, short event)
+ * void operator() (int signum, eventxx::type event)
* {
* if (i < 5) std::cout << "keep going...\n";
* else
* }
* @endcode
*
- * You can see some more examples on the test directory of the distribution or
- * on the examples related page.
+ * You can see more examples on the test directory of the distribution or on the
+ * examples related page.
*
*
* @section Status
*
- * This library was not widely used yet, it lack some testing. Because templates
- * are not even compiled when they are used, you can be surprissed if you catch
- * a piece of code that didn't got even compiled yet because the lack of
- * testing. The library has no support for buffered events yet either. It
- * doesn't support the http stuff, and probably never will because that has
- * nothing to do with event handling.
- *
- * If you notice this lib leaks memory, don't blame me, blame libevent :)
- * libevent has a known bug on event_base_free() that makes it assert always, so
- * event_base_free() it's unusable, unless you patch your libevent (for example,
- * using this <a
- * href="http://monkeymail.org/archives/libevent-users/2006-April/000141.html">patch</a>
- * written by Mark D. Anderson and who knows why it's not still applied. If you
- * do so, you can compile your programs with -DEVENT_BASE_FREE_FIX so
- * event_base_free() gets called.
- *
- * That said, I think it's pretty usable anyways. If something is broken it
- * would be really easy to fix it because is just a simple wrapper arround
- * libevent. So, please try it out, and if you have any problems,
- * <a href="mailto:llucax+eventxx@gmail.com">drop me an
+ * This library has not been widely used yet, but it's used in some serious
+ * projects, so I think it's moderately stable now. The library has no support
+ * for buffered events yet, but patches are welcome. It doesn't support the
+ * HTTP stuff, and probably never will because that has nothing to do with
+ * event handling.
+ *
+ * @libevent had a memory leak before version 1.3b (before 1.2 it didn't even
+ * had a way free that memory, from version 1.2 to 1.3a, if you tried to free the
+ * memory the program abort() because a failed assertion). Because of that,
+ * there is a way to disable the @link eventxx::dispatcher::~dispatcher()
+ * destructor @endlink (which calls the inexistent/broken @c event_base_free()
+ * function). So if you use a @libevent version previous to 1.3b, you have to
+ * compile your programs defining the EVENTXX_NO_EVENT_BASE_FREE macro.
+ *
+ * If something is broken it would be really easy to fix because @eventxx is
+ * just a simple wrapper around @libevent. So, please try it out, and if you
+ * have any problems, <a href="mailto:llucax+eventxx@gmail.com">drop me an
* e-mail</a> and and I'll fix it ASAP (or provide a patch and you will be my
* best friend ;).
*
- * Patches to support buffered events are welcome too.
- *
+ * If you use this library, please drop me an e-mail with your thoughts, or
+ * simply saying "I use it", so I can keep track of how many people really use
+ * it.
*
* @author Leandro Lucarella <llucax+eventxx@gmail.com>
*
- * @version 0.1
+ * @version 0.6
*
* @par License
* This program is under the BOLA license (see
- * http://auriga.wearlab.de/~alb/bola/ for more info or the
+ * http://auriga.wearlab.de/~alb/bola/ for more details or read the
* <a href="http://www.llucax.com.ar/~luca/repos/eventxx/LICENSE">LICENSE</a>
- * file itself).
+ * file itself, it's very short and it basically says it's Public Domain).
*
*/
/** @example c-way.cpp
*
- * This is a simple example ilustrating the usage with C-like callback
+ * This is a simple example illustrating the usage with C-like callback
* functions.
*/
/** @example functor-way.cpp
*
- * This is a simple example ilustrating the usage with function object
+ * This is a simple example illustrating the usage with function object
* callbacks.
*/
+/** @example wrapped-functor-way.cpp
+ *
+ * This is a simple example illustrating the usage with an arbitrary member
+ * function as an event handler callbacks.
+ */
+
/** @example mixed-way.cpp
*
- * This is a simple example ilustrating the usage with a mix of C-like callbacks
+ * This is a simple example illustrating the usage with a mix of C-like callbacks
* and function object callbacks.
*/
/** @example prio-test.cpp
*
- * This is a priotity usage example.
+ * This is a priority usage example.
*/
/** @example test-time.cpp
*
- * This is a timer usage example.
+ * This is a timer usage example ported from libevent.
*/
-/** @example test-weof.cpp
+/** @example test-eof.cpp
*
* This is some kind of test of EOF ported from libevent.
*/
+/** @example test-weof.cpp
+ *
+ * Another test of EOF ported from libevent.
+ */
+
/** @example trivial.cpp
*
* This is the most trivial example.
* Invalid priority exception.
*
* This exception is thrown when passing an invalid priority to a function. This
- * usually means you don't have enought priority queues in your dispatcher, so
+ * usually means you don't have enough priority queues in your dispatcher, so
* you should have allocated more in the constructor.
*
* If you hit this exception, you probably got a programming error.
//@}
-/// Miscelaneous constants
+/// Miscellaneous constants
enum
{
DEFAULT_PRIORITY = -1, ///< Default priority (the middle value).
};
-/// C function used as callback in the C API.
-typedef void (*ccallback_type)(int, short, void*);
-
-
/**
* Time used for timeout values.
*
* function objects (see eventxx::event, eventxx::timer and eventxx::signal
* templates). The former are just typedef'ed specialization of the later.
*
+ * A member function wrapper functor (eventxx::mem_cb) is also included,
+ * so you can use any member function (method) as an event handler.
+ *
+ * Please note that C-like function callback take a short as the type of event,
+ * while functors (or member functions) use eventxx::type.
+ *
* All events derive from a plain class (not template) eventxx::basic_event, one
* of the main utilities of it (besides containing common code ;) is to be used
* in STL containers.
*/
//@{
+
+/// C function used as callback in the C API.
+typedef void (*ccallback_type)(int, short, void*);
+
+
/**
* Type of events.
*
PERSIST = EV_PERSIST ///< Not really an event, is an event modifier.
};
+inline
+type operator| (const type& t1, const type& t2)
+{
+ int r = static_cast< int >(t1) | static_cast< int >(t2);
+ return *reinterpret_cast< type* >(&r);
+}
+
+
/**
* Basic event from which all events derive.
*
/**
* Generic event object.
*
- * This object stores all the information about an event, incluiding a callback
+ * This object stores all the information about an event, including a callback
* functor, which is called when the event is fired. The template parameter
* must be a functor (callable object or function) that can take 2 parameters:
* an integer (the file descriptor of the fired event) and an event::type (the
* type of event being fired).
* There is a specialized version of this class which takes as the template
- * parameter a C function with the ccallback_type signature, just like C
- * libevent API does.
+ * parameter a C function with the eventxx::ccallback_type signature, just like
+ * C @libevent API does.
*
* @see eventxx::event< ccallback_type >
*/
* @param ev Type of events to monitor (see eventxx::type).
* @param handler Callback functor.
*/
- event(int fd, short ev, F& handler) throw()
+ event(int fd, type ev, F& handler) throw()
{
- event_set(this, fd, ev, &wrapper,
+ event_set(this, fd, static_cast< short >(ev), &wrapper,
reinterpret_cast< void* >(&handler));
}
* @param handler C-style callback function.
* @param arg Arbitrary pointer to pass to the handler as argument.
*/
- event(int fd, short ev, ccallback_type handler, void* arg) throw()
+ event(int fd, type ev, ccallback_type handler, void* arg = 0) throw()
{
- event_set(this, fd, ev, handler, arg);
+ event_set(this, fd, static_cast< short >(ev), handler, arg);
}
protected:
* @param handler C-style callback function.
* @param arg Arbitrary pointer to pass to the handler as argument.
*/
- timer(ccallback_type handler, void* arg) throw()
+ timer(ccallback_type handler, void* arg = 0) throw()
{
evtimer_set(this, handler, arg);
}
{
/**
- * Creates a new singal event.
+ * Creates a new signal event.
*
* @param signum Signal number to monitor.
* @param handler Callback functor.
* @param handler C-style callback function.
* @param arg Arbitrary pointer to pass to the handler as argument.
*/
- signal(int signum, ccallback_type handler, void* arg) throw()
+ signal(int signum, ccallback_type handler, void* arg = 0) throw()
{
signal_set(this, signum, handler, arg);
}
/// Shortcut to C-style signal handler.
typedef eventxx::signal< ccallback_type > csignal;
+/**
+ * Helper functor to use an arbitrary member function as an event handler.
+ *
+ * With this wrapper, you can use any object method, which accepts the right
+ * parameters (int, short) and returns void, as an event handler. This way you
+ * don't have to overload the operator() which can be confusing depending on the
+ * context.
+ *
+ * You can see an usage example in the Examples Section.
+ */
+template < typename O, typename M >
+struct mem_cb
+{
+
+ /**
+ * Member function callback constructor.
+ *
+ * It expects to receive a class as the first parameter (O), and a
+ * member function (of that class O) as the second parameter.
+ *
+ * When this instance is called with fd and ev as function arguments,
+ * object.method(fd, ev) will be called.
+ *
+ * @param object Object to be used.
+ * @param method Method to be called.
+ */
+ mem_cb(O& object, M method) throw():
+ _object(object), _method(method) {}
+
+ void operator() (int fd, type ev) { (_object.*_method)(fd, ev); }
+ protected:
+ O& _object;
+ M _method;
+
+}; // struct mem_cb
//@}
/**
* Event dispatcher.
*
- * This class is the responsable for looping and dispatching events. Everytime
+ * This class is the responsible for looping and dispatching events. Every time
* you need an event loop you should create an instance of this class.
*
* You can @link dispatcher::add add @endlink events to the dispatcher, and you
*/
dispatcher() throw()
{
- _event_base = static_cast< internal::event_base* >(internal::event_init());
+ _event_base = static_cast< internal::event_base* >(
+ internal::event_init());
}
/**
*/
dispatcher(int npriorities) throw(std::bad_alloc)
{
- _event_base = static_cast< internal::event_base* >(internal::event_init());
+ _event_base = static_cast< internal::event_base* >(
+ internal::event_init());
if (!_event_base) throw std::bad_alloc();
// Can't fail because there is no way that it has active events
internal::event_base_priority_init(_event_base, npriorities);
}
-#ifdef EVENT_BASE_FREE_FIX
+#ifndef EVENTXX_NO_EVENT_BASE_FREE
+ /// Free dispatcher resources, see @ref Status section for details.
~dispatcher() throw() { event_base_free(_event_base); }
-#else
-#warning "The dispatcher class *will* leak memory because of a libevent bug, see http://www.mail-archive.com/libevent-users@monkey.org/msg00110.html for more info an a patch. If you already have this patch, please -DEVENT_BASE_FREE_FIX to your compiler to make this message disappear and really free the dispatcher memory using event_base_free()."
#endif
/**
if (priority != DEFAULT_PRIORITY
&& internal::event_priority_set(&e, priority))
throw invalid_priority();
- internal::event_add(&e, const_cast< time* >(&to)); // XXX HACK libevent don't use const
+ // XXX HACK libevent don't use const
+ internal::event_add(&e, const_cast< time* >(&to));
}
/**
template < typename F >
void add_once(int fd, type ev, F& handler)
{
- internal::event_once(fd, ev, &dispatcher::wrapper< F >,
- reinterpret_cast< void* >(&handler), 0);
+ internal::event_once(fd, static_cast< short>(ev),
+ &dispatcher::wrapper< F >,
+ reinterpret_cast< void* >(&handler), 0);
}
/**
*/
void add_once(int fd, type ev, ccallback_type handler, void* arg)
{
- internal::event_once(fd, ev, handler, arg, 0);
+ internal::event_once(fd, static_cast< short >(ev), handler,
+ arg, 0);
}
/**
template < typename F >
void add_once(int fd, type ev, F& handler, const time& to)
{
- internal::event_once(fd, ev, &dispatcher::wrapper< F >,
- reinterpret_cast< void* >(&handler),
- const_cast< time* >(&to)); // XXX HACK libevent don't use const
+ internal::event_once(fd, static_cast< short >(ev),
+ &dispatcher::wrapper< F >,
+ reinterpret_cast< void* >(&handler),
+ // XXX HACK libevent don't use const
+ const_cast< time* >(&to));
}
/**
* @param arg Arbitrary pointer to pass to the handler as argument.
* @param to Timeout.
*/
- void add_once(int fd, type ev, ccallback_type handler, void* arg, const time& to)
+ void add_once(int fd, type ev, ccallback_type handler, void* arg,
+ const time& to)
{
- internal::event_once(fd, ev, handler, arg, const_cast< time* >(&to)); // XXX HACK libevent don't use const
+ internal::event_once(fd, static_cast< short >(ev), handler, arg,
+ // XXX HACK libevent don't use const
+ const_cast< time* >(&to));
}
/**
{
internal::event_once(-1, EV_TIMEOUT, &dispatcher::wrapper< F >,
reinterpret_cast< void* >(&handler),
- const_cast< time* >(&to)); // XXX HACK libevent don't use const
+ // XXX HACK libevent don't use const
+ const_cast< time* >(&to));
}
/**
*/
void add_once_timer(ccallback_type handler, void* arg, const time& to)
{
- internal::event_once(-1, EV_TIMEOUT, handler, arg, const_cast< time* >(&to)); // XXX HACK libevent don't use const
+ // XXX HACK libevent don't use const
+ internal::event_once(-1, EV_TIMEOUT, handler, arg,
+ const_cast< time* >(&to));
}
/**
* @param flags If eventxx::ONCE is specified, then just one event is
* processed, if eventxx::NONBLOCK is specified, then this
* function returns even if there are no pending events.
+ *
+ * @return 0 if eventxx::NONBLOCK or eventxx::ONCE is set, 1 if there
+ * are no more events registered and EINTR if you use the
+ * @libevent's @c event_gotsig and return -1 in your
+ * @c event_sigcb callback.
*/
- int dispatch(int flags = 0) // TODO throw(exception)
+ int dispatch(int flags = 0) throw()
{
return internal::event_base_loop(_event_base, flags);
}
*
* @param to If a timeout is given, the loop exits after the specified
* time is elapsed.
+ *
+ * @return Not very well specified by @libevent :-/ that's why it
+ * doesn't throw an exception either.
*/
- int exit(const time& to = time())
+ int exit(const time& to = time()) throw() // TODO throw(exception)
{
// XXX HACK libevent don't use const
return internal::event_base_loopexit(_event_base,
protected:
internal::event_base* _event_base;
template < typename F >
- static void wrapper(int fd, type ev, void* h)
+ static void wrapper(int fd, short ev, void* h)
{
F& handler = *reinterpret_cast< F* >(h);
handler(fd, *reinterpret_cast< type* >(&ev));
}; // struct dispatcher
-
-} // namespace event
+} // namespace eventxx
#endif // _EVENTXX_HPP_
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