#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.
+ * The <a href="http://monkey.org/~provos/libevent/">libevent</a> 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
* 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.
+ * *BSD, Mac OS X, Solaris and Windows.
*
- * 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
+ * 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 get the
+ * <a href="http://www.llucax.com.ar/~luca/eventxx/releases/current.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
+ * 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.
+ *
+ * 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
+ * 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.
+ *
+ * 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).
+ *
+ * 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 ;).
+ *
+ * @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 some 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't be surprised 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 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>
*
- * @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 info or the
+ * <a href="http://www.llucax.com.ar/~luca/repos/eventxx/LICENSE">LICENSE</a>
+ * file itself).
*
*/
+/** @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 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)
+ DEFAULT_PRIORITY = -1, ///< Default priority (the middle value).
+ ONCE = EVLOOP_ONCE, ///< Loop just once.
+ NONBLOCK = EVLOOP_NONBLOCK ///< Don't block the event loop.
};
}; // 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.
+ *
+ * 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.
+ */
//@{
+/**
+ * Type of events.
+ *
+ * There are 4 kind of events: eventxx::TIMEOUT, eventxx::READ, eventxx::WRITE
+ * or eventxx::SIGNAL. eventxx::PERSIST is not an event, is an event modifier
+ * flag, that tells eventxx that this event should live until dispatcher::del()
+ * is called. You can use, for example:
+ * @code
+ * eventxx::event(fd, eventxx::READ | eventxx::PERSIST, ...);
+ * @endcode
+ */
+enum type
+{
+ TIMEOUT = EV_TIMEOUT, ///< Timeout event.
+ READ = EV_READ, ///< Read event.
+ WRITE = EV_WRITE, ///< Write event.
+ SIGNAL = EV_SIGNAL, ///< Signal event.
+ PERSIST = EV_PERSIST ///< Not really an event, is an event modifier.
+};
+
/**
* Basic event from which all events derive.
*
*
* @return true if there is a pending event, false if not.
*/
- bool pending(short ev) const throw()
+ bool pending(type ev) const throw()
{
// HACK libevent don't use const
return event_pending(const_cast< basic_event* >(this), ev, 0);
*
* @param priority New event priority.
*
+ * @pre The event must be added to some dispatcher.
+ *
* @see dispatcher::dispatcher(int)
*/
void priority(int priority) const throw(invalid_event, invalid_priority)
/**
* Generic event object.
*
- * This object stores all the information about an event, incluiding a callback
- * functor, which is called then the event is fired. Then template parameter
- * must be a callable object (functor) that can take 2 parameters: an integer
- * (the file descriptor of the fired event) and a short (the type of event
- * fired: EV_TIMEOUT, EV_SIGNAL, EV_READ, EV_WRITE). There is an 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.
+ * 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.
*
* @see eventxx::event< ccallback_type >
*/
* Creates a new event.
*
* @param fd File descriptor to monitor for events.
- * @param ev Type of events to monitor.
+ * @param ev Type of events to monitor (see eventxx::type).
* @param handler Callback functor.
- * @param priority Priority of the event.
*/
- event(int fd, short ev, F& handler, int priority = DEFAULT_PRIORITY)
- throw(invalid_priority)
+ event(int fd, short ev, F& handler) throw()
{
- event_set(this, fd, ev, &wrapper, reinterpret_cast< void* >(&handler));
- if (priority != DEFAULT_PRIORITY
- && event_priority_set(this, priority))
- throw invalid_priority();
+ event_set(this, fd, ev, &wrapper,
+ reinterpret_cast< void* >(&handler));
}
protected:
static void wrapper(int fd, short ev, void* h)
{
F& handler = *reinterpret_cast< F* >(h);
- handler(fd, ev);
+ // Hackish, but this way the handler can get a clean
+ // event type
+ handler(fd, *reinterpret_cast< type* >(&ev));
}
}; // struct event< F >
* Creates a new event.
*
* @param fd File descriptor to monitor for events.
- * @param ev Type of events to monitor.
+ * @param ev Type of events to monitor (see eventxx::type).
* @param handler C-style callback function.
* @param arg Arbitrary pointer to pass to the handler as argument.
- * @param priority Priority of the event.
*/
- event(int fd, short ev, ccallback_type handler, void* arg,
- int priority = DEFAULT_PRIORITY)
- throw(invalid_priority)
+ event(int fd, short ev, ccallback_type handler, void* arg) throw()
{
event_set(this, fd, ev, handler, arg);
- if (priority != DEFAULT_PRIORITY
- && event_priority_set(this, priority))
- throw invalid_priority();
}
protected:
* Timer event object.
*
* This is just a special case of event that is fired only when a timeout is
- * reached. It's just a shortcut to event(-1, 0, handler, priority).
+ * reached. It's just a shortcut to:
+ * @code
+ * event(-1, 0, handler);
+ * @endcode
*
- * @note This event can't EV_PERSIST.
+ * @note This event can't eventxx::PERSIST.
* @see timer< ccallback_type >
*/
template < typename F >
* Creates a new timer event.
*
* @param handler Callback functor.
- * @param priority Priority of the event.
*/
- timer(F& handler, int priority = DEFAULT_PRIORITY)
- throw(invalid_priority)
+ timer(F& handler) throw()
{
evtimer_set(this, &event< F >::wrapper,
reinterpret_cast< void* >(&handler));
- if (priority != DEFAULT_PRIORITY
- && event_priority_set(this, priority))
- throw invalid_priority();
}
}; // struct timer< F >
/**
* This is the specialization of eventxx::timer for C-style callbacks.
*
- * @note This event can't EV_PERSIST.
+ * @note This event can't eventxx::PERSIST.
* @see timer
*/
template <>
/**
* Creates a new timer event.
- *
+ *
* @param handler C-style callback function.
* @param arg Arbitrary pointer to pass to the handler as argument.
- * @param priority Priority of the event.
*/
- timer(ccallback_type handler, void* arg, int priority = DEFAULT_PRIORITY)
- throw(invalid_priority)
+ timer(ccallback_type handler, void* arg) throw()
{
evtimer_set(this, handler, arg);
- if (priority != DEFAULT_PRIORITY
- && event_priority_set(this, priority))
- throw invalid_priority();
}
}; // struct timer< ccallback_type >
* Signal event object.
*
* This is just a special case of event that is fired when a signal is raised
- * (instead of a file descriptor being active). It's just a shortcut to
- * event(signal, EV_SIGNAL, handler, priority).
+ * (instead of a file descriptor being active). It's just a shortcut to:
+ * @code
+ * event(signum, eventxx::SIGNAL, handler);
+ * @endcode
*
- * @note This event allways EV_PERSIST.
+ * @note This event always eventxx::PERSIST.
* @see signal< ccallback_type >
*/
template < typename F >
{
/**
- * Creates a new singal event.
+ * Creates a new signal event.
*
* @param signum Signal number to monitor.
* @param handler Callback functor.
- * @param priority Priority of the event.
*/
- signal(int signum, F& handler, int priority = DEFAULT_PRIORITY)
- throw(invalid_priority)
+ signal(int signum, F& handler) throw()
{
signal_set(this, signum, &event< F >::wrapper,
reinterpret_cast< void* >(&handler));
- if (priority != DEFAULT_PRIORITY
- && event_priority_set(this, priority))
- throw invalid_priority();
}
/**
/**
* This is the specialization of eventxx::signal for C-style callbacks.
*
- * @note This event allways EV_PERSIST.
+ * @note This event always eventxx::PERSIST.
* @see signal
*/
template <>
* @param signum Signal number to monitor.
* @param handler C-style callback function.
* @param arg Arbitrary pointer to pass to the handler as argument.
- * @param priority Priority of the event.
*/
- signal(int signum, ccallback_type handler, void* arg,
- int priority = DEFAULT_PRIORITY)
- throw(invalid_priority)
+ signal(int signum, ccallback_type handler, void* arg) throw()
{
signal_set(this, signum, handler, arg);
- if (priority != DEFAULT_PRIORITY
- && event_priority_set(this, priority))
- throw invalid_priority();
}
/**
* Event's signal number.
- *
+ *
* @return Event's signal number.
*/
int signum() const
/**
* 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
{
/**
- * Creates a default dispatcher (with just 1 prioriority).
+ * Creates a default dispatcher (with just 1 priority).
*
* @see dispatcher(int) if you want to create a dispatcher with more
- * prioriorities.
+ * priorities.
*/
dispatcher() throw()
{
}
/**
- * Creates a dispatcher with npriorities prioriorities.
- *
+ * Creates a dispatcher with npriorities priorities.
+ *
* @param npriorities Number of priority queues to use.
*/
dispatcher(int npriorities) throw(std::bad_alloc)
#ifdef EVENT_BASE_FREE_FIX
~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
/**
* Adds an event to the dispatcher.
*
* @param e Event to add.
+ * @param priority Priority of the event.
*/
- void add(basic_event& e) throw()
+ void add(basic_event& e, int priority = DEFAULT_PRIORITY)
+ throw(invalid_priority)
{
internal::event_base_set(_event_base, &e);
+ if (priority != DEFAULT_PRIORITY
+ && internal::event_priority_set(&e, priority))
+ throw invalid_priority();
internal::event_add(&e, 0);
}
/**
* Adds an event to the dispatcher with a timeout.
*
- * The event is fired when there is activity on e or when to is elapsed,
+ * The event is fired when there is activity on e or when to has elapsed,
* whatever come first.
*
* @param e Event to add.
* @param to Timeout.
+ * @param priority Priority of the event.
*/
- void add(basic_event& e, const time& to) throw()
+ void add(basic_event& e, const time& to,
+ int priority = DEFAULT_PRIORITY)
+ throw(invalid_priority)
{
internal::event_base_set(_event_base, &e);
+ 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
}
* Adds a temporary event.
*
* Adds a temporary event, without the need of instantiating a new event
- * object. Events added this way can't EV_PERSIST.
+ * object. Events added this way can't eventxx::PERSIST.
*
* @param fd File descriptor to monitor for events.
* @param ev Type of events to monitor.
* @param handler Callback function.
*/
template < typename F >
- void add_once(int fd, short ev, F& handler)
+ void add_once(int fd, type ev, F& handler)
{
internal::event_once(fd, ev, &dispatcher::wrapper< F >,
reinterpret_cast< void* >(&handler), 0);
* Adds a temporary event to with a C-style callback.
*
* Adds a temporary event, without the need of instantiating a new event
- * object. Events added this way can't EV_PERSIST.
+ * object. Events added this way can't eventxx::PERSIST.
*
* @param fd File descriptor to monitor for events.
* @param ev Type of events to monitor.
* @param handler Callback function.
* @param arg Arbitrary pointer to pass to the handler as argument.
*/
- void add_once(int fd, short ev, ccallback_type handler, void* arg)
+ void add_once(int fd, type ev, ccallback_type handler, void* arg)
{
internal::event_once(fd, ev, handler, arg, 0);
}
* Adds a temporary event.
*
* Adds a temporary event, without the need of instantiating a new event
- * object. Events added this way can't EV_PERSIST.
+ * object. Events added this way can't eventxx::PERSIST.
*
* @param fd File descriptor to monitor for events.
* @param ev Type of events to monitor.
* @param to Timeout.
*/
template < typename F >
- void add_once(int fd, short ev, F& handler, const time& to)
+ void add_once(int fd, type ev, F& handler, const time& to)
{
internal::event_once(fd, ev, &dispatcher::wrapper< F >,
reinterpret_cast< void* >(&handler),
* Adds a temporary event with a C-style callback.
*
* Adds a temporary event, without the need of instantiating a new event
- * object. Events added this way can't EV_PERSIST.
+ * object. Events added this way can't eventxx::PERSIST.
*
* @param fd File descriptor to monitor for events.
* @param ev Type of events to monitor.
* @param arg Arbitrary pointer to pass to the handler as argument.
* @param to Timeout.
*/
- void add_once(int fd, short 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
}
/**
* Main dispatcher loop.
*
- * This function takes the control of the program, waiting for event and
- * calling it's callbacks when they are fired. It only returns under
+ * This function takes the control of the program, waiting for an event
+ * and calling its callbacks when it's fired. It only returns under
* this conditions:
* - exit() was called.
* - All events were del()eted.
* - Another internal error.
- * - LOOP_ONCE flag was set.
- * - LOOP_NONBLOCK flag was set.
+ * - eventxx::ONCE flag was set.
+ * - eventxx::NONBLOCK flag was set.
*
- * @param flags If EVLOOP_ONCE is specified, then just one event is
- * processed, if EVLOOP_NONBLOCK is specified, then this
- * function returns whenever as an event or not.
+ * @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.
*/
int dispatch(int flags = 0) // TODO throw(exception)
{
/**
* Exit the dispatch() loop.
*
- * @param to If a timeout is given, the loop exits after to is passed.
+ * @param to If a timeout is given, the loop exits after the specified
+ * time is elapsed.
*/
int exit(const time& to = time())
{
- return internal::event_base_loopexit(_event_base, const_cast< time* >(&to)); // XXX HACK libevent don't use const
+ // XXX HACK libevent don't use const
+ return internal::event_base_loopexit(_event_base,
+ const_cast< time* >(&to));
}
protected:
internal::event_base* _event_base;
template < typename F >
- static void wrapper(int fd, short ev, void* h)
+ static void wrapper(int fd, type ev, void* h)
{
F& handler = *reinterpret_cast< F* >(h);
- handler(fd, ev);
+ handler(fd, *reinterpret_cast< type* >(&ev));
}
}; // struct dispatcher
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