X-Git-Url: https://git.llucax.com/software/eventxx.git/blobdiff_plain/1df0df01b00d420fcfbcb4ad0c0a74e885c828df..f96e870a834c80bffa69ff1395ff35e263d65861:/eventxx?ds=sidebyside diff --git a/eventxx b/eventxx index 7143ae2..dc0a479 100644 --- a/eventxx +++ b/eventxx @@ -1,7 +1,7 @@ #ifndef _EVENTXX_HPP_ #define _EVENTXX_HPP_ -#include // timeval (hack -> event.h don't include it) +#include // timeval #include // std::exception, std::invalid_argument, // std::runtime_error, std::bad_alloc @@ -9,42 +9,212 @@ * * @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 current + * release from the + * release + * directory or grab the + * most up to date + * sources from the darcs repository. + * + * You can also take a look the the darcsweb interface to see + * the latest + * changes online or subscribe to its + * RSS + * feed 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 + * #include + * #include + * + * 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 have to + * 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 patch + * 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, + * drop me an + * e-mail 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 * - * @author Leandro Lucarella * @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 + * LICENSE + * 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 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. @@ -60,7 +230,14 @@ namespace internal } -/// @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. + */ //@{ @@ -101,7 +278,7 @@ struct invalid_event: public std::invalid_argument, public exception * 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. @@ -127,10 +304,12 @@ struct invalid_priority: public std::invalid_argument, public exception //@} -/// 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. }; @@ -186,9 +365,42 @@ struct time: ::timeval }; // 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. * @@ -208,7 +420,7 @@ struct basic_event: internal::event * * @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); @@ -232,6 +444,8 @@ struct basic_event: internal::event * * @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) @@ -267,13 +481,14 @@ struct basic_event: internal::event /** * 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 eventxx::ccallback_type signature, just like + * C @libevent API does. * * @see eventxx::event< ccallback_type > */ @@ -285,12 +500,13 @@ struct event: basic_event * 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. */ event(int fd, short ev, F& handler) throw() { - event_set(this, fd, ev, &wrapper, reinterpret_cast< void* >(&handler)); + event_set(this, fd, ev, &wrapper, + reinterpret_cast< void* >(&handler)); } protected: @@ -298,7 +514,9 @@ struct event: basic_event 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 > @@ -317,11 +535,11 @@ struct event< ccallback_type >: basic_event * 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. */ - 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); } @@ -336,9 +554,12 @@ struct event< ccallback_type >: basic_event * 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). + * 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 > @@ -362,7 +583,7 @@ struct timer: event< 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 <> @@ -371,11 +592,11 @@ struct timer< ccallback_type >: event< ccallback_type > /** * Creates a new timer event. - * + * * @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); } @@ -387,10 +608,12 @@ struct timer< ccallback_type >: event< 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). + * (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 > @@ -398,7 +621,7 @@ struct signal: event< F > { /** - * Creates a new singal event. + * Creates a new signal event. * * @param signum Signal number to monitor. * @param handler Callback functor. @@ -425,7 +648,7 @@ struct signal: event< F > /** * 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 <> @@ -439,14 +662,14 @@ struct signal< ccallback_type >: event< ccallback_type > * @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); } /** * Event's signal number. - * + * * @return Event's signal number. */ int signum() const @@ -473,37 +696,54 @@ typedef eventxx::signal< ccallback_type > csignal; /** * 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() { - _event_base = static_cast< internal::event_base* >(internal::event_init()); + _event_base = static_cast< internal::event_base* >( + internal::event_init()); } /** - * 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) { - _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 /** @@ -525,7 +765,7 @@ struct dispatcher /** * 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. @@ -540,21 +780,22 @@ struct dispatcher 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)); } /** * 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); @@ -564,14 +805,14 @@ struct dispatcher * 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); } @@ -580,7 +821,7 @@ struct dispatcher * 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. @@ -588,18 +829,19 @@ struct dispatcher * @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), - const_cast< time* >(&to)); // XXX HACK libevent don't use const + // XXX HACK libevent don't use const + const_cast< time* >(&to)); } /** * 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. @@ -607,9 +849,12 @@ struct dispatcher * @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 + internal::event_once(fd, ev, handler, arg, + // XXX HACK libevent don't use const + const_cast< time* >(&to)); } /** @@ -626,7 +871,8 @@ struct dispatcher { 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)); } /** @@ -641,7 +887,9 @@ struct dispatcher */ 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)); } /** @@ -659,20 +907,25 @@ struct dispatcher /** * 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 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. * - * @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. + * @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); } @@ -680,20 +933,26 @@ struct dispatcher /** * 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. + * + * @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) { - 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