--- cvsroot/EV/EV.pm 2007/11/28 17:32:24 1.57 +++ cvsroot/EV/EV.pm 2007/12/22 16:37:07 1.79 @@ -60,7 +60,8 @@ below is comprehensive, one might also consult the documentation of libev itself (L) for more subtle details on watcher semantics or some discussion on the available backends, or how to -force a specific backend with C. +force a specific backend with C, or just about in any case +because it has much more detailed information. =cut @@ -69,7 +70,7 @@ use strict; BEGIN { - our $VERSION = '1.4'; + our $VERSION = '2.0'; use XSLoader; XSLoader::load "EV", $VERSION; } @@ -87,6 +88,53 @@ @EV::Fork::ISA = "EV::Watcher"; +@EV::Loop::Default::ISA = "EV::Loop"; + +=head1 EVENT LOOPS + +EV supports multiple event loops: There is a single "default event loop" +that can handle everything including signals and child watchers, and any +number of "dynamic event loops" that can use different backends (with +various limitations), but no child and signal watchers. + +You do not have to do anything to create the default event loop: When +the module is loaded a suitable backend is selected on the premise of +selecting a working backend (which for example rules out kqueue on most +BSDs). Modules should, unless they have "special needs" always use the +default loop as this is fastest (perl-wise), best supported by other +modules (e.g. AnyEvent or Coro) and most portable event loop. + +For specific programs you can create additional event loops dynamically. + +=over 4 + +=item $loop = new EV::loop [$flags] + +Create a new event loop as per the specified flags. Please refer to the +C function description in the libev documentation +(L) +for more info. + +The loop will automatically be destroyed when it is no longer referenced +by any watcher and the loop object goes out of scope. + +Using C is recommended, as only the default event loop +is protected by this module. + +=item $loop->loop_fork + +Must be called after a fork in the child, before entering or continuing +the event loop. An alternative is to use C which calls +this fucntion automatically, at some performance loss (refer to the libev +documentation). + +=item $loop = EV::default_loop [$flags] + +Return the default loop (which is a singleton object). + +=back + + =head1 BASIC INTERFACE =over 4 @@ -94,28 +142,44 @@ =item $EV::DIED Must contain a reference to a function that is called when a callback -throws an exception (with $@ containing thr error). The default prints an +throws an exception (with $@ containing the error). The default prints an informative message and continues. If this callback throws an exception it will be silently ignored. +=item $flags = EV::supported_backends + +=item $flags = EV::recommended_backends + +=item $flags = EV::embeddable_backends + +Returns the set (see C flags) of backends supported by this +instance of EV, the set of recommended backends (supposed to be good) for +this platform and the set of embeddable backends (see EMBED WATCHERS). + =item $time = EV::time Returns the current time in (fractional) seconds since the epoch. =item $time = EV::now +=item $time = $loop->now + Returns the time the last event loop iteration has been started. This is the time that (relative) timers are based on, and refering to it is usually faster then calling EV::time. -=item $method = EV::method +=item $backend = EV::backend + +=item $backend = $loop->backend Returns an integer describing the backend used by libev (EV::METHOD_SELECT or EV::METHOD_EPOLL). =item EV::loop [$flags] +=item $loop->loop ([$flags]) + Begin checking for events and calling callbacks. It returns when a callback calls EV::unloop. @@ -127,14 +191,25 @@ =item EV::unloop [$how] +=item $loop->unloop ([$how]) + When called with no arguments or an argument of EV::UNLOOP_ONE, makes the innermost call to EV::loop return. When called with an argument of EV::UNLOOP_ALL, all calls to EV::loop will return as fast as possible. +=item $count = EV::loop_count + +=item $count = $loop->loop_count + +Return the number of times the event loop has polled for new +events. Sometiems useful as a generation counter. + =item EV::once $fh_or_undef, $events, $timeout, $cb->($revents) +=item $loop->once ($fh_or_undef, $events, $timeout, $cb->($revents)) + This function rolls together an I/O and a timer watcher for a single one-shot event without the need for managing a watcher object. @@ -149,16 +224,43 @@ When an error occurs or either the timeout or I/O watcher triggers, then the callback will be called with the received event set (in general -you can expect it to be a combination of C, C, +you can expect it to be a combination of C, C, C and C). EV::once doesn't return anything: the watchers stay active till either of them triggers, then they will be stopped and freed, and the callback invoked. +=item EV::feed_fd_event ($fd, $revents) + +=item $loop->feed_fd_event ($fd, $revents) + +Feed an event on a file descriptor into EV. EV will react to this call as +if the readyness notifications specified by C<$revents> (a combination of +C and C) happened on the file descriptor C<$fd>. + +=item EV::feed_signal_event ($signal) + +Feed a signal event into EV. EV will react to this call as if the signal +specified by C<$signal> had occured. + +=item EV::set_io_collect_interval $time + +=item $loop->set_io_collect_interval ($time) + +=item EV::set_timeout_collect_interval $time + +=item $loop->set_timeout_collect_interval ($time) + +These advanced functions set the minimum block interval when polling for I/O events and the minimum +wait interval for timer events. See the libev documentation at +L for +a more detailed discussion. + =back -=head2 WATCHER OBJECTS + +=head1 WATCHER OBJECTS A watcher is an object that gets created to record your interest in some event. For instance, if you want to wait for STDIN to become readable, you @@ -166,7 +268,7 @@ my $watcher = EV::io *STDIN, EV::READ, sub { my ($watcher, $revents) = @_; - warn "yeah, STDIN should not be readable without blocking!\n" + warn "yeah, STDIN should now be readable without blocking!\n" }; All watchers can be active (waiting for events) or inactive (paused). Only @@ -177,7 +279,7 @@ Each watcher type has its associated bit in revents, so you can use the same callback for multiple watchers. The event mask is named after the type, i..e. EV::child sets EV::CHILD, EV::prepare sets EV::PREPARE, -EV::periodic sets EV::PERIODIC and so on, with the exception of IO events +EV::periodic sets EV::PERIODIC and so on, with the exception of I/O events (which can set both EV::READ and EV::WRITE bits), and EV::timer (which uses EV::TIMEOUT). @@ -209,7 +311,7 @@ Stop a watcher if it is active. Also clear any pending events (events that have been received but that didn't yet result in a callback invocation), -regardless of wether the watcher was active or not. +regardless of whether the watcher was active or not. =item $bool = $w->is_active @@ -249,10 +351,21 @@ Note that the priority semantics have not yet been fleshed out and are subject to almost certain change. -=item $w->trigger ($revents) +=item $w->invoke ($revents) Call the callback *now* with the given event mask. +=item $w->feed_event ($revents) + +Feed some events on this watcher into EV. EV will react to this call as if +the watcher had received the given C<$revents> mask. + +=item $revents = $w->clear_pending + +If the watcher is pending, this function clears its pending status and +returns its C<$revents> bitset (as if its callback was invoked). If the +watcher isn't pending it does nothing and returns C<0>. + =item $previous_state = $w->keepalive ($bool) Normally, C will return when there are no active watchers @@ -261,7 +374,7 @@ call C once and when it returns you know that all your jobs are finished (or they forgot to register some watchers for their task :). -Sometimes, however, this gets in your way, for example when you the module +Sometimes, however, this gets in your way, for example when the module that calls C (usually the main program) is not the same module as a long-living watcher (for example a DNS client module written by somebody else even). Then you might want any outstanding requests to be @@ -274,21 +387,25 @@ The initial value for keepalive is true (enabled), and you cna change it any time. -Example: Register an IO watcher for some UDP socket but do not keep the +Example: Register an I/O watcher for some UDP socket but do not keep the event loop from running just because of that watcher. my $udp_socket = ... my $udp_watcher = EV::io $udp_socket, EV::READ, sub { ... }; - $udp_watcher->keepalive (0); + $1000udp_watcher->keepalive (0); + +=item $loop = $w->loop + +Return the loop that this watcher is attached to. =back -=head2 WATCHER TYPES +=head1 WATCHER TYPES Each of the following subsections describes a single watcher type. -=head3 IO WATCHERS - is this file descriptor readable or writable? +=head3 I/O WATCHERS - is this file descriptor readable or writable? =over 4 @@ -296,6 +413,10 @@ =item $w = EV::io_ns $fileno_or_fh, $eventmask, $callback +=item $w = $loop->io ($fileno_or_fh, $eventmask, $callback) + +=item $w = $loop->io_ns ($fileno_or_fh, $eventmask, $callback) + As long as the returned watcher object is alive, call the C<$callback> when at least one of events specified in C<$eventmask> occurs. @@ -334,6 +455,10 @@ =item $w = EV::timer_ns $after, $repeat, $callback +=item $w = $loop->timer ($after, $repeat, $callback) + +=item $w = $loop->timer_ns ($after, $repeat, $callback) + Calls the callback after C<$after> seconds (which may be fractional). If C<$repeat> is non-zero, the timer will be restarted (with the $repeat value as $after) after the callback returns. @@ -384,6 +509,10 @@ =item $w = EV::periodic_ns $at, $interval, $reschedule_cb, $callback +=item $w = $loop->periodic ($at, $interval, $reschedule_cb, $callback) + +=item $w = $loop->periodic_ns ($at, $interval, $reschedule_cb, $callback) + Similar to EV::timer, but is not based on relative timeouts but on absolute times. Apart from creating "simple" timers that trigger "at" the specified time, it can also be used for non-drifting absolute timers and @@ -467,6 +596,10 @@ Simply stops and starts the watcher again. +=item $time = $w->at + +Return the time that the watcher is expected to trigger next. + =back @@ -513,6 +646,10 @@ =item $w = EV::child_ns $pid, $callback +=item $w = $loop->child ($pid, $callback) + +=item $w = $loop->child_ns ($pid, $callback) + Call the callback when a status change for pid C<$pid> (or any pid if C<$pid> is 0) has been received. More precisely: when the process receives a C, EV will fetch the outstanding exit/wait status for all @@ -563,6 +700,10 @@ =item $w = EV::stat_ns $path, $interval, $callback +=item $w = $loop->stat ($path, $interval, $callback) + +=item $w = $loop->stat_ns ($path, $interval, $callback) + Call the callback when a file status change has been detected on C<$path>. The C<$path> does not need to exist, changing from "path exists" to "path does not exist" is a status change like any other. @@ -642,12 +783,28 @@ =item $w = EV::idle_ns $callback -Call the callback when there are no pending io, timer/periodic, signal or -child events, i.e. when the process is idle. +=item $w = $loop->idle ($callback) + +=item $w = $loop->idle_ns ($callback) + +Call the callback when there are no other pending watchers of the same or +higher priority (excluding check, prepare and other idle watchers of the +same or lower priority, of course). They are called idle watchers because +when the watcher is the highest priority pending event in the process, the +process is considered to be idle at that priority. + +If you want a watcher that is only ever called when I other events are +outstanding you have to set the priority to C. The process will not block as long as any idle watchers are active, and they will be called repeatedly until stopped. +For example, if you have idle watchers at priority C<0> and C<1>, and +an I/O watcher at priority C<0>, then the idle watcher at priority C<1> +and the I/O watcher will always run when ready. Only when the idle watcher +at priority C<1> is stopped and the I/O watcher at priority C<0> is not +pending with the C<0>-priority idle watcher be invoked. + The C variant doesn't start (activate) the newly created watcher. =back @@ -661,6 +818,10 @@ =item $w = EV::prepare_ns $callback +=item $w = $loop->prepare ($callback) + +=item $w = $loop->prepare_ns ($callback) + Call the callback just before the process would block. You can still create/modify any watchers at this point. @@ -679,6 +840,10 @@ =item $w = EV::check_ns $callback +=item $w = $loop->check ($callback) + +=item $w = $loop->check_ns ($callback) + Call the callback just after the process wakes up again (after it has gathered events), but before any other callbacks have been invoked. @@ -697,7 +862,7 @@ # make the dispatcher handle any outstanding stuff ... not shown - # create an IO watcher for each and every socket + # create an I/O watcher for each and every socket @snmp_watcher = ( (map { EV::io $_, EV::READ, sub { } } keys %{ $dispatcher->{_descriptors} }), @@ -742,6 +907,10 @@ =item $w = EV::fork_ns $callback +=item $w = $loop->fork ($callback) + +=item $w = $loop->fork_ns ($callback) + Call the callback before the event loop is resumed in the child process after a fork. @@ -750,6 +919,73 @@ =back +=head3 EMBED WATCHERS - when one backend isn't enough... + +This is a rather advanced watcher type that lets you embed one event loop +into another (currently only IO events are supported in the embedded +loop, other types of watchers might be handled in a delayed or incorrect +fashion and must not be used). + +See the libev documentation at +L +for more details. + +In short, this watcher is most useful on BSD systems without working +kqueue to still be able to handle a large number of sockets: + + my $socket_loop; + + # check wether we use SELECT or POLL _and_ KQUEUE is supported + if ( + (EV::backend & (EV::BACKEND_POLL | EV::BACKEND_SELECT)) + && (EV::supported_backends & EV::embeddable_backends & EV::BACKEND_KQUEUE) + ) { + # use kqueue for sockets + $socket_loop = new EV::Loop EV::BACKEND_KQUEUE | EV::FLAG_NOENV; + } + + # use the default loop otherwise + $socket_loop ||= EV::default_loop; + +=over 4 + +=item $w = EV::embed $otherloop, $callback + +=item $w = EV::embed_ns $otherloop, $callback + +=item $w = $loop->embed ($otherloop, $callback) + +=item $w = $loop->embed_ns ($otherloop, $callback) + +Call the callback when the embedded event loop (C<$otherloop>) has any +I/O activity. The C<$callback> should alwas be specified as C in +this version of EV, which means the embedded event loop will be managed +automatically. + +The C variant doesn't start (activate) the newly created watcher. + +=back + + +=head1 PERL SIGNALS + +While Perl signal handling (C<%SIG>) is not affected by EV, the behaviour +with EV is as the same as any other C library: Perl-signals will only be +handled when Perl runs, which means your signal handler might be invoked +only the next time an event callback is invoked. + +The solution is to use EV signal watchers (see C), which will +ensure proper operations with regards to other event watchers. + +If you cannot do this for whatever reason, you can also force a watcher +to be called on every event loop iteration by installing a C +watcher: + + my $async_check = EV::check sub { }; + +This ensures that perl gets into control for a short time to handle any +pending signals, and also ensures (slightly) slower overall operation. + =head1 THREADS Threads are not supported by this module in any way. Perl pseudo-threads @@ -780,13 +1016,15 @@ }; default_loop - or die 'EV: cannot initialise libev backend. bad $ENV{LIBEV_METHODS}?'; + or die 'EV: cannot initialise libev backend. bad $ENV{LIBEV_FLAGS}?'; 1; =head1 SEE ALSO -L. +L (asynchronous DNS), L (makes Glib/Gtk2 use EV as +event loop), L (embed Glib into EV), L (efficient +coroutines with EV), L (asynchronous SNMP). =head1 AUTHOR