#ifndef _EVENTXX_HPP_
#define _EVENTXX_HPP_
-#include <sys/types.h> // timeval (hack -> event.h don't include it)
+#include <sys/types.h> // timeval
#include <stdexcept> // std::exception, std::invalid_argument,
// std::runtime_error, std::bad_alloc
*
* @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 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.
*
- * 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.
+ * @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).
*
- * 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.
+ * 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.
*
- * This is a simple, direct, one-header inline C++ wrapper for libevent.
- * 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 @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> 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
*
- * The best way to explain how this works is by examples. TODO
+ * 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 simpler, so I hope nobody complains about it ;).
+ * See eventxx::dispatcher documentation for more details.
+ *
+ * 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 @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 @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 have
+ * been warned ;).
+ *
+ *
+ * @section Example
+ *
+ * @code
+ * #include <eventxx>
+ * #include <iostream>
+ * #include <csignal>
+ *
+ * struct handler
+ * {
+ * eventxx::dispatcher& d;
+ * int i;
+ * handler(eventxx::dispatcher& d): d(d), i(0) {}
+ * void operator() (int signum, short event)
+ * {
+ * if (i < 5) std::cout << "keep going...\n";
+ * else
+ * {
+ * std::cout << "done!\n";
+ * d.exit();
+ * }
+ * }
+ * };
+ *
+ * void sighandler(int signum, short event, void* data)
+ * {
+ * int& i = *static_cast< int* >(data);
+ * std::cout << ++i << " interrupts, ";
+ * }
+ *
+ * int main()
+ * {
+ * eventxx::dispatcher d;
+ * handler h(d);
+ * eventxx::csignal sigev(SIGINT, sighandler, &h.i);
+ * eventxx::signal< handler > e(SIGINT, h);
+ * d.add(sigev);
+ * d.add(e);
+ * d.dispatch();
+ * return 0;
+ * }
+ * @endcode
+ *
+ * You can see more examples on the test directory of the distribution or on the
+ * examples related page.
+ *
+ *
+ * @section Status
+ *
+ * This library has not been widely used yet, so it lacks proper testing.
+ * Because templates are not even compiled when they are not used, don't be
+ * surprised if you catch a piece of code that doesn't compile. The library
+ * has no support for buffered events yet. It doesn't support the HTTP stuff,
+ * and probably never will because that has nothing to do with event handling.
+ *
+ * If you notice that when using @eventxx your program leaks some memory, don't
+ * blame me, blame @libevent :) @libevent has a known bug on @c event_base_free()
+ * that makes it assert always, so @c event_base_free() is 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 @c -DEVENT_BASE_FREE_FIX so
+ * @c event_base_free() gets called in the eventxx::dispatcher @link
+ * eventxx::dispatcher::~dispatcher() destructor @endlink.
+ *
+ * That said, I think it's still pretty usable anyways. 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.
+ *
+ *
+ * @author Leandro Lucarella <llucax+eventxx@gmail.com>
+ *
+ * @version 0.2
*
- * @author Leandro Lucarella <llucarella@integratech.com.ar>
- * @version 0.1
* @par License
- * This program is under the BOLA license (see
- * http://auriga.wearlab.de/~alb/bola/)
+ * This program is under the BOLA license (see
+ * 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, it's very short and it basically says it's Public Domain).
+ *
+ */
+
+/** @example c-way.cpp
+ *
+ * This is a simple example illustrating the usage with C-like callback
+ * functions.
+ */
+
+/** @example functor-way.cpp
+ *
+ * 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 illustrating the usage with a mix of C-like callbacks
+ * and function object callbacks.
+ */
+
+/** @example bench.cpp
*
+ * This is a benchmark example, extracted from libevent and ported to eventxx.
*/
+/** @example prio-test.cpp
+ *
+ * This is a priority usage example.
+ */
+
+/** @example test-time.cpp
+ *
+ * This is a timer usage example ported from libevent.
+ */
+
+/** @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.
+ */
/**
* Namespace for all symbols libevent C++ wrapper defines.
}
-/// @defgroup exceptions Exceptions
+/** @defgroup exceptions Exceptions
+ *
+ * eventxx makes a heavy use of exceptions. Each function has it's exceptions
+ * specified, so it's very easy to find out what exceptions to expect.
+ *
+ * Exceptions are mostly thrown when there is a programming error. So if you get
+ * an exception check your code.
+ */
//@{
* 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).
}; // struct time
-/// @defgroup events Events
+/** @defgroup events Events
+ *
+ * There are many ways to specify how to handle an event. You can use use the
+ * same plain functions callbacks (see eventxx::cevent, eventxx::ctimer and
+ * eventxx::csignal) like in C or the other kind of more advanced, stateful
+ * 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.
+ *
+ * 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.
+ *
+ * Please see each class documentation for details and examples.
+ */
//@{
/**
/**
* 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 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, short ev, ccallback_type handler, void* arg = 0) throw()
{
event_set(this, fd, ev, handler, arg);
}
* @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, short 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.
+ * 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
+ * can @link dispatcher::del remove @endlink them later or you can @link
+ * dispatcher::add_once add events to be processed just once @endlink. You can
+ * @link dispatcher::dispatch loop once or forever @endlink (well, of course you
+ * can break that forever removing all the events or by @link dispatcher::exit
+ * exiting the loop @endlink).
*/
struct dispatcher
{
*/
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
+ /// 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));
}
/**
{
internal::event_once(fd, ev, &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));
}
/**
* @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, 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,
}; // struct dispatcher
-
-} // namespace event
+} // namespace eventxx
#endif // _EVENTXX_HPP_
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