--- cvsroot/EV/EV.pm 2007/10/26 19:11:35 1.4 +++ cvsroot/EV/EV.pm 2007/11/01 17:20:25 1.21 @@ -1,49 +1,59 @@ =head1 NAME -EV - perl interface to libevent, monkey.org/~provos/libevent/ +EV - perl interface to libev, a high performance full-featured event loop =head1 SYNOPSIS - use EV; - - # TIMER - - my $w = EV::timer 2, 0, sub { - warn "is called after 2s"; - }; - - my $w = EV::timer 2, 1, sub { - warn "is called roughly every 2s (repeat = 1)"; - }; - - undef $w; # destroy event watcher again - - # IO - - my $w = EV::timer_abs 0, 60, sub { - warn "is called every minute, on the minute, exactly"; - }; - - my $w = EV::io \*STDIN, EV::READ | EV::PERSIST, sub { - my ($w, $events) = @_; # all callbacks get the watcher object and event mask - if ($events & EV::TIMEOUT) { - warn "nothign received on stdin for 10 seconds, retrying"; - } else { - warn "stdin is readable, you entered: ", ; - } - }; - $w->timeout (10); - - # MAINLOOP - EV::dispatch; # loop as long as watchers are active - EV::loop; # the same thing - EV::loop EV::LOOP_ONCE; - EV::loop EV::LOOP_ONSHOT; + use EV; + + # TIMERS + + my $w = EV::timer 2, 0, sub { + warn "is called after 2s"; + }; + + my $w = EV::timer 2, 1, sub { + warn "is called roughly every 2s (repeat = 1)"; + }; + + undef $w; # destroy event watcher again + + my $w = EV::periodic 0, 60, sub { + warn "is called every minute, on the minute, exactly"; + }; + + # IO + + my $w = EV::io *STDIN, EV::READ, sub { + my ($w, $revents) = @_; # all callbacks get the watcher object and event mask + warn "stdin is readable, you entered: ", ; + }; + + # SIGNALS + + my $w = EV::signal 'QUIT', sub { + warn "sigquit received\n"; + }; + + my $w = EV::signal 3, sub { + warn "sigquit received (this is GNU/Linux, right?)\n"; + }; + + # CHILD/PID STATUS CHANGES + + my $w = EV::child 666, sub { + my ($w, $revents, $status) = @_; + }; + + # MAINLOOP + EV::loop; # loop until EV::loop_done is called + EV::loop EV::LOOP_ONESHOT; # block until at least one event could be handled + EV::loop EV::LOOP_NONBLOCK; # try to handle same events, but do not block =head1 DESCRIPTION -This module provides an interface to libevent -(L). +This module provides an interface to libev +(L). =cut @@ -52,165 +62,382 @@ use strict; BEGIN { - our $VERSION = '0.01'; + our $VERSION = '0.1'; use XSLoader; XSLoader::load "EV", $VERSION; } -=head1 FUNCTIONAL INTERFACE +@EV::Io::ISA = +@EV::Timer::ISA = +@EV::Periodic::ISA = +@EV::Signal::ISA = +@EV::Idle::ISA = +@EV::Prepare::ISA = +@EV::Check::ISA = +@EV::Child::ISA = "EV::Watcher"; + +=head1 BASIC INTERFACE =over 4 -=item $EV::NPRI +=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 +informative message and continues. + +If this callback throws an exception it will be silently ignored. + +=item $time = EV::time -How many priority levels are available. +Returns the current time in (fractional) seconds since the epoch. =item $time = EV::now -Returns the time in (fractional) seconds since the epoch. +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 $version = EV::version +=item $method = EV::ev_method -=item $method = EV::method +Returns an integer describing the backend used by libev (EV::METHOD_SELECT +or EV::METHOD_EPOLL). -Return version string and event polling method used. +=item EV::loop [$flags] -=item EV::loop $flags # EV::LOOP_ONCE, EV::LOOP_ONESHOT +Begin checking for events and calling callbacks. It returns when a +callback calls EV::loop_done. -=item EV::loopexit $after +The $flags argument can be one of the following: -Exit any active loop or dispatch after C<$after> seconds or immediately if -C<$after> is missing or zero. + 0 as above + EV::LOOP_ONESHOT block at most once (wait, but do not loop) + EV::LOOP_NONBLOCK do not block at all (fetch/handle events but do not wait) -=item EV::dispatch +=item EV::loop_done [$how] -Same as C. +When called with no arguments or an argument of 1, makes the innermost +call to EV::loop return. -=item EV::event $callback +When called with an agrument of 2, all calls to EV::loop will return as +fast as possible. -Creates a new event watcher waiting for nothing, calling the given callback. +=back -=item my $w = EV::io $fileno_or_fh, $eventmask, $callback +=head2 WATCHER -=item my $w = EV::io_ns $fileno_or_fh, $eventmask, $callback +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 +would create an EV::io watcher for that: + + my $watcher = EV::io *STDIN, EV::READ, sub { + my ($watcher, $revents) = @_; + warn "yeah, STDIN should not be readable without blocking!\n" + }; + +All watchers can be active (waiting for events) or inactive (paused). Only +active watchers will have their callbacks invoked. All callbacks will be +called with at least two arguments: the watcher and a bitmask of received +events. + +Each watcher type has its associated bit in revents, so you can use the +same callback for multiple watchers. The event mask is named after the +type, i..e. EV::child sets EV::CHILD, EV::prepare sets EV::PREPARE, +EV::periodic sets EV::PERIODIC and so on, with the exception of IO events +(which can set both EV::READ and EV::WRITE bits), and EV::timer (which +uses EV::TIMEOUT). + +In the rare case where one wants to create a watcher but not start it at +the same time, each constructor has a variant with a trailing C<_ns> in +its name, e.g. EV::io has a non-starting variant EV::io_ns and so on. + +Please note that a watcher will automatically be stopped when the watcher +object is returned, so you I to keep the watcher objects returned by +the constructors. + +=head2 WATCHER TYPES + +Now lets move to the existing watcher types and asociated methods. + +The following methods are available for all watchers. Then followes a +description of each watcher constructor (EV::io, EV::timer, EV::periodic, +EV::signal, EV::child, EV::idle, EV::prepare and EV::check), followed by +any type-specific methods (if any). -As long as the returned watcher object is alive, call the C<$callback> -when the events specified in C<$eventmask> happen. Initially, the timeout -is disabled. +=over 4 + +=item $w->start + +Starts a watcher if it isn't active already. Does nothing to an already +active watcher. By default, all watchers start out in the active state +(see the description of the C<_ns> variants if you need stopped watchers). + +=item $w->stop + +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. + +=item $bool = $w->is_active + +Returns true if the watcher is active, false otherwise. + +=item $current_cb = $w->cb + +=item $old_cb = $w->cb ($new_cb) + +Queries the callback on the watcher and optionally changes it. You cna do +this at any time. + +=item $w->trigger ($revents) -The C variant doesn't add/start the newly created watcher. +Call the callback *now* with the given event mask. -Eventmask can be one or more of these constants ORed together: + +=item $w = EV::io $fileno_or_fh, $eventmask, $callback + +=item $w = EV::io_ns $fileno_or_fh, $eventmask, $callback + +As long as the returned watcher object is alive, call the C<$callback> +when the events specified in C<$eventmask>. + +The $eventmask can be one or more of these constants ORed together: EV::READ wait until read() wouldn't block anymore EV::WRITE wait until write() wouldn't block anymore - EV::PERSIST stay active after an event occured -=item my $w = EV::timer $after, $repeat, $callback +The C variant doesn't start (activate) the newly created watcher. + +=item $w->set ($fileno_or_fh, $eventmask) + +Reconfigures the watcher, see the constructor above for details. Can be +called at any time. + +=item $current_fh = $w->fh + +=item $old_fh = $w->fh ($new_fh) + +Returns the previously set filehandle and optionally set a new one. + +=item $current_eventmask = $w->events + +=item $old_eventmask = $w->events ($new_eventmask) + +Returns the previously set event mask and optionally set a new one. + + +=item $w = EV::timer $after, $repeat, $callback -=item my $w = EV::timer_ns $after, $repeat, $callback +=item $w = EV::timer_ns $after, $repeat, $callback -Calls the callback after C<$after> seconds. If C<$repeat> is true, the -timer will be restarted after the callback returns. This means that the -callback would be called roughly every C<$after> seconds, prolonged by the -time the callback takes. +Calls the callback after C<$after> seconds. If C<$repeat> is non-zero, +the timer will be restarted (with the $repeat value as $after) after the +callback returns. -The C variant doesn't add/start the newly created watcher. +This means that the callback would be called roughly after C<$after> +seconds, and then every C<$repeat> seconds. "Roughly" because the time of +callback processing is not taken into account, so the timer will slowly +drift. If that isn't acceptable, look at EV::periodic. -=item my $w = EV::timer_abs $at, $interval, $callback +The timer is based on a monotonic clock, that is if somebody is sitting +in front of the machine while the timer is running and changes the system +clock, the timer will nevertheless run (roughly) the same time. -=item my $w = EV::timer_abs_ns $at, $interval, $callback +The C variant doesn't start (activate) the newly created watcher. + +=item $w->set ($after, $repeat) + +Reconfigures the watcher, see the constructor above for details. Can be at +any time. + +=item $w->again + +Similar to the C method, but has special semantics for repeating timers: + +If the timer is active and repeating, reset the timeout to occur +C<$repeat> seconds after now. + +If the timer is active and non-repeating, it will be stopped. + +If the timer is in active and repeating, start it. + +Otherwise do nothing. + +This behaviour is useful when you have a timeout for some IO +operation. You create a timer object with the same value for C<$after> and +C<$repeat>, and then, in the read/write watcher, run the C method +on the timeout. + + +=item $w = EV::periodic $at, $interval, $callback + +=item $w = EV::periodic_ns $at, $interval, $callback Similar to EV::timer, but the time is given as an absolute point in time (C<$at>), plus an optional C<$interval>. If the C<$interval> is zero, then the callback will be called at the time -C<$at> if that is in the future, or as soon as possible if its in the +C<$at> if that is in the future, or as soon as possible if it is in the past. It will not automatically repeat. If the C<$interval> is nonzero, then the watcher will always be scheduled -to time out at the next C<$at + integer * $interval> time. +to time out at the next C<$at + N * $interval> time. This can be used to schedule a callback to run at very regular intervals, as long as the processing time is less then the interval (otherwise obviously events will be skipped). -The C variant doesn't add/start the newly created watcher. +Another way to think about it (for the mathematically inclined) is that +EV::periodic will try to run the callback at the next possible time where +C<$time = $at (mod $interval)>, regardless of any time jumps. -=item my $w = EV::signal $signum, $callback +This periodic timer is based on "wallclock time", that is, if the clock +changes (C, C etc.), then the timer will nevertheless run at +the specified time. This means it will never drift (it might jitter, but +it will not drift). -=item my $w = EV::signal_ns $signum, $callback +The C variant doesn't start (activate) the newly created watcher. -Call the callback when signal $signum is received. +=item $w->set ($at, $interval) -The C variant doesn't add/start the newly created watcher. +Reconfigures the watcher, see the constructor above for details. Can be at +any time. -=back -=head1 THE EV::Event CLASS +=item $w = EV::signal $signal, $callback -All EV functions creating an event watcher (designated by C -above) support the following methods on the returned watcher object: +=item $w = EV::signal_ns $signal, $callback -=over 4 +Call the callback when $signal is received (the signal can be specified +by number or by name, just as with kill or %SIG). -=item $w->add ($timeout) +EV will grab the signal for the process (the kernel only allows one +component to receive a signal at a time) when you start a signal watcher, +and removes it again when you stop it. Perl does the same when you +add/remove callbacks to %SIG, so watch out. -Stops and (re-)starts the event watcher, setting the optional timeout to -the given value, or clearing the timeout if none is given. +You can have as many signal watchers per signal as you want. -=item $w->start +The C variant doesn't start (activate) the newly created watcher. -Stops and (re-)starts the event watcher without touching the timeout. +=item $w->set ($signal) -=item $w->del +Reconfigures the watcher, see the constructor above for details. Can be at +any time. -=item $w->stop -Stop the event watcher if it was started. +=item $w = EV::child $pid, $callback -=item $current_callback = $w->cb +=item $w = EV::child_ns $pid, $callback -=item $old_callback = $w->cb ($new_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 SIGCHLD, EV will fetch the outstanding exit/wait status for all +changed/zombie children and call the callback. -Return the previously set callback and optionally set a new one. +Unlike all other callbacks, this callback will be called with an +additional third argument which is the exit status. See the C +function for details. -=item $current_fh = $w->fh +You can have as many pid watchers per pid as you want. -=item $old_fh = $w->fh ($new_fh) +The C variant doesn't start (activate) the newly created watcher. -Returns the previously set filehandle and optionally set a new one. +=item $w->set ($pid) -=item $current_eventmask = $w->events +Reconfigures the watcher, see the constructor above for details. Can be at +any time. -=item $old_eventmask = $w->events ($new_eventmask) -Returns the previously set event mask and optionally set a new one. +=item $w = EV::idle $callback + +=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. + +The process will not block as long as any idle watchers are active, and +they will be called repeatedly until stopped. + +The C variant doesn't start (activate) the newly created watcher. + + +=item $w = EV::prepare $callback + +=item $w = EV::prepare_ns $callback + +Call the callback just before the process would block. You can still +create/modify any watchers at this point. + +See the EV::check watcher, below, for explanations and an example. + +The C variant doesn't start (activate) the newly created watcher. -=item $w->timeout ($after, $repeat) -Resets the timeout (see C for details). +=item $w = EV::check $callback -=item $w->timeout_abs ($at, $interval) +=item $w = EV::check_ns $callback -Resets the timeout (see C for details). +Call the callback just after the process wakes up again (after it has +gathered events), but before any other callbacks have been invoked. -=item $w->priority_set ($priority) +This is used to integrate other event-based software into the EV +mainloop: You register a prepare callback and in there, you create io and +timer watchers as required by the other software. Here is a real-world +example of integrating Net::SNMP (with some details left out): -Set the priority of the watcher to C<$priority> (0 <= $priority < $EV::NPRI). + our @snmp_watcher; + + our $snmp_prepare = EV::prepare sub { + # do nothing unless active + $dispatcher->{_event_queue_h} + or return; + + # make the dispatcher handle any outstanding stuff + + # create an IO watcher for each and every socket + @snmp_watcher = ( + (map { EV::io $_, EV::READ, sub { } } + keys %{ $dispatcher->{_descriptors} }), + ); + + # if there are any timeouts, also create a timer + push @snmp_watcher, EV::timer $event->[Net::SNMP::Dispatcher::_TIME] - EV::now, 0, sub { } + if $event->[Net::SNMP::Dispatcher::_ACTIVE]; + }; + +The callbacks are irrelevant, the only purpose of those watchers is +to wake up the process as soon as one of those events occurs (socket +readable, or timer timed out). The corresponding EV::check watcher will then +clean up: + + our $snmp_check = EV::check sub { + # destroy all watchers + @snmp_watcher = (); + + # make the dispatcher handle any new stuff + }; + +The callbacks of the created watchers will not be called as the watchers +are destroyed before this cna happen (remember EV::check gets called +first). + +The C variant doesn't start (activate) the newly created watcher. =back -=head1 BUGS +=head1 THREADS -Lots. Libevent itself isn't well tested and rather buggy, and this module -is quite new at the moment. +Threads are not supported by this in any way. Perl pseudo-threads is evil +stuff and must die. =cut -our $NPRI = 4; -our $BASE = init; -priority_init $NPRI; +our $DIED = sub { + warn "EV: error in callback (ignoring): $@"; +}; + +init; push @AnyEvent::REGISTRY, [EV => "EV::AnyEvent"]; @@ -218,7 +445,7 @@ =head1 SEE ALSO - L, L, L, L. + L, L. =head1 AUTHOR