[ViewVC] Diff of: cvs/EV/EV.pm

Comparing EV/EV.pm (file contents):
Revision 1.1 by root, Fri Oct 26 16:50:05 2007 UTC vs.
Revision 1.48 by root, Fri Nov 23 13:09:02 2007 UTC

1	=head1 NAME	1	=head1 NAME
2		2
3	EV - perl interface to libevent, monkey.org/~provos/libevent/	3	EV - perl interface to libev, a high performance full-featured event loop
4		4
5	=head1 SYNOPSIS	5	=head1 SYNOPSIS
6		6
7	use EV;	7	use EV;
		8
		9	# TIMERS
		10
		11	my $w = EV::timer 2, 0, sub {
		12	warn "is called after 2s";
		13	};
		14
		15	my $w = EV::timer 2, 2, sub {
		16	warn "is called roughly every 2s (repeat = 2)";
		17	};
		18
		19	undef $w; # destroy event watcher again
		20
		21	my $w = EV::periodic 0, 60, 0, sub {
		22	warn "is called every minute, on the minute, exactly";
		23	};
		24
		25	# IO
		26
		27	my $w = EV::io *STDIN, EV::READ, sub {
		28	my ($w, $revents) = @_; # all callbacks receive the watcher and event mask
		29	warn "stdin is readable, you entered: ", <STDIN>;
		30	};
		31
		32	# SIGNALS
		33
		34	my $w = EV::signal 'QUIT', sub {
		35	warn "sigquit received\n";
		36	};
		37
		38	# CHILD/PID STATUS CHANGES
		39
		40	my $w = EV::child 666, sub {
		41	my ($w, $revents) = @_;
		42	my $status = $w->rstatus;
		43	};
		44
		45	# MAINLOOP
		46	EV::loop; # loop until EV::unloop is called or all watchers stop
		47	EV::loop EV::LOOP_ONESHOT; # block until at least one event could be handled
		48	EV::loop EV::LOOP_NONBLOCK; # try to handle same events, but do not block
8		49
9	=head1 DESCRIPTION	50	=head1 DESCRIPTION
10		51
11	This module provides an interface to libevent	52	This module provides an interface to libev
12	(L<http://monkey.org/~provos/libevent/>).	53	(L<http://software.schmorp.de/pkg/libev.html>).
13		54
14	=cut	55	=cut
15		56
16	package EV;	57	package EV;
17		58
18	use strict;	59	use strict;
19		60
20	BEGIN {	61	BEGIN {
21	our $VERSION = '0.01';	62	our $VERSION = '1.2';
22	use XSLoader;	63	use XSLoader;
23	XSLoader::load "EV", $VERSION;	64	XSLoader::load "EV", $VERSION;
24	}	65	}
25		66
26	=head1 FUNCTIONAL INTERFACE	67	@EV::Io::ISA =
		68	@EV::Timer::ISA =
		69	@EV::Periodic::ISA =
		70	@EV::Signal::ISA =
		71	@EV::Idle::ISA =
		72	@EV::Prepare::ISA =
		73	@EV::Check::ISA =
		74	@EV::Child::ISA = "EV::Watcher";
		75
		76	=head1 BASIC INTERFACE
27		77
28	=over 4	78	=over 4
29		79
		80	=item $EV::DIED
		81
		82	Must contain a reference to a function that is called when a callback
		83	throws an exception (with $@ containing thr error). The default prints an
		84	informative message and continues.
		85
		86	If this callback throws an exception it will be silently ignored.
		87
		88	=item $time = EV::time
		89
		90	Returns the current time in (fractional) seconds since the epoch.
		91
		92	=item $time = EV::now
		93
		94	Returns the time the last event loop iteration has been started. This
		95	is the time that (relative) timers are based on, and refering to it is
		96	usually faster then calling EV::time.
		97
		98	=item $method = EV::method
		99
		100	Returns an integer describing the backend used by libev (EV::METHOD_SELECT
		101	or EV::METHOD_EPOLL).
		102
		103	=item EV::loop [$flags]
		104
		105	Begin checking for events and calling callbacks. It returns when a
		106	callback calls EV::unloop.
		107
		108	The $flags argument can be one of the following:
		109
		110	0 as above
		111	EV::LOOP_ONESHOT block at most once (wait, but do not loop)
		112	EV::LOOP_NONBLOCK do not block at all (fetch/handle events but do not wait)
		113
		114	=item EV::unloop [$how]
		115
		116	When called with no arguments or an argument of EV::UNLOOP_ONE, makes the
		117	innermost call to EV::loop return.
		118
		119	When called with an argument of EV::UNLOOP_ALL, all calls to EV::loop will return as
		120	fast as possible.
		121
		122	=item EV::once $fh_or_undef, $events, $timeout, $cb->($revents)
		123
		124	This function rolls together an I/O and a timer watcher for a single
		125	one-shot event without the need for managing a watcher object.
		126
		127	If C<$fh_or_undef> is a filehandle or file descriptor, then C<$events>
		128	must be a bitset containing either C<EV::READ>, C<EV::WRITE> or C<EV::READ
		129	\| EV::WRITE>, indicating the type of I/O event you want to wait for. If
		130	you do not want to wait for some I/O event, specify C<undef> for
		131	C<$fh_or_undef> and C<0> for C<$events>).
		132
		133	If timeout is C<undef> or negative, then there will be no
		134	timeout. Otherwise a EV::timer with this value will be started.
		135
		136	When an error occurs or either the timeout or I/O watcher triggers, then
		137	the callback will be called with the received event set (in general
		138	you can expect it to be a combination of C<EV:ERROR>, C<EV::READ>,
		139	C<EV::WRITE> and C<EV::TIMEOUT>).
		140
		141	EV::once doesn't return anything: the watchers stay active till either
		142	of them triggers, then they will be stopped and freed, and the callback
		143	invoked.
		144
30	=back	145	=back
31		146
		147	=head2 WATCHER
32		148
33	=head1 OBJECT-ORIENTED INTERFACE	149	A watcher is an object that gets created to record your interest in some
		150	event. For instance, if you want to wait for STDIN to become readable, you
		151	would create an EV::io watcher for that:
34		152
35	The object oriented interface lets you configure your own encoding or	153	my $watcher = EV::io *STDIN, EV::READ, sub {
36	decoding style, within the limits of supported formats.	154	my ($watcher, $revents) = @_;
		155	warn "yeah, STDIN should not be readable without blocking!\n"
		156	};
		157
		158	All watchers can be active (waiting for events) or inactive (paused). Only
		159	active watchers will have their callbacks invoked. All callbacks will be
		160	called with at least two arguments: the watcher and a bitmask of received
		161	events.
		162
		163	Each watcher type has its associated bit in revents, so you can use the
		164	same callback for multiple watchers. The event mask is named after the
		165	type, i..e. EV::child sets EV::CHILD, EV::prepare sets EV::PREPARE,
		166	EV::periodic sets EV::PERIODIC and so on, with the exception of IO events
		167	(which can set both EV::READ and EV::WRITE bits), and EV::timer (which
		168	uses EV::TIMEOUT).
		169
		170	In the rare case where one wants to create a watcher but not start it at
		171	the same time, each constructor has a variant with a trailing C<_ns> in
		172	its name, e.g. EV::io has a non-starting variant EV::io_ns and so on.
		173
		174	Please note that a watcher will automatically be stopped when the watcher
		175	object is destroyed, so you I<need> to keep the watcher objects returned by
		176	the constructors.
		177
		178	Also, all methods changing some aspect of a watcher (->set, ->priority,
		179	->fh and so on) automatically stop and start it again if it is active,
		180	which means pending events get lost.
		181
		182	=head2 WATCHER TYPES
		183
		184	Now lets move to the existing watcher types and asociated methods.
		185
		186	The following methods are available for all watchers. Then followes a
		187	description of each watcher constructor (EV::io, EV::timer, EV::periodic,
		188	EV::signal, EV::child, EV::idle, EV::prepare and EV::check), followed by
		189	any type-specific methods (if any).
37		190
38	=over 4	191	=over 4
39		192
		193	=item $w->start
		194
		195	Starts a watcher if it isn't active already. Does nothing to an already
		196	active watcher. By default, all watchers start out in the active state
		197	(see the description of the C<_ns> variants if you need stopped watchers).
		198
		199	=item $w->stop
		200
		201	Stop a watcher if it is active. Also clear any pending events (events that
		202	have been received but that didn't yet result in a callback invocation),
		203	regardless of wether the watcher was active or not.
		204
		205	=item $bool = $w->is_active
		206
		207	Returns true if the watcher is active, false otherwise.
		208
		209	=item $current_data = $w->data
		210
		211	=item $old_data = $w->data ($new_data)
		212
		213	Queries a freely usable data scalar on the watcher and optionally changes
		214	it. This is a way to associate custom data with a watcher:
		215
		216	my $w = EV::timer 60, 0, sub {
		217	warn $_[0]->data;
		218	};
		219	$w->data ("print me!");
		220
		221	=item $current_cb = $w->cb
		222
		223	=item $old_cb = $w->cb ($new_cb)
		224
		225	Queries the callback on the watcher and optionally changes it. You can do
		226	this at any time without the watcher restarting.
		227
		228	=item $current_priority = $w->priority
		229
		230	=item $old_priority = $w->priority ($new_priority)
		231
		232	Queries the priority on the watcher and optionally changes it. Pending
		233	watchers with higher priority will be invoked first. The valid range of
		234	priorities lies between EV::MAXPRI (default 2) and EV::MINPRI (default
		235	-2). If the priority is outside this range it will automatically be
		236	normalised to the nearest valid priority.
		237
		238	The default priority of any newly-created weatcher is 0.
		239
		240	=item $w->trigger ($revents)
		241
		242	Call the callback now with the given event mask.
		243
		244
		245	=item $w = EV::io $fileno_or_fh, $eventmask, $callback
		246
		247	=item $w = EV::io_ns $fileno_or_fh, $eventmask, $callback
		248
		249	As long as the returned watcher object is alive, call the C<$callback>
		250	when the events specified in C<$eventmask>.
		251
		252	The $eventmask can be one or more of these constants ORed together:
		253
		254	EV::READ wait until read() wouldn't block anymore
		255	EV::WRITE wait until write() wouldn't block anymore
		256
		257	The C<io_ns> variant doesn't start (activate) the newly created watcher.
		258
		259	=item $w->set ($fileno_or_fh, $eventmask)
		260
		261	Reconfigures the watcher, see the constructor above for details. Can be
		262	called at any time.
		263
		264	=item $current_fh = $w->fh
		265
		266	=item $old_fh = $w->fh ($new_fh)
		267
		268	Returns the previously set filehandle and optionally set a new one.
		269
		270	=item $current_eventmask = $w->events
		271
		272	=item $old_eventmask = $w->events ($new_eventmask)
		273
		274	Returns the previously set event mask and optionally set a new one.
		275
		276
		277	=item $w = EV::timer $after, $repeat, $callback
		278
		279	=item $w = EV::timer_ns $after, $repeat, $callback
		280
		281	Calls the callback after C<$after> seconds. If C<$repeat> is non-zero,
		282	the timer will be restarted (with the $repeat value as $after) after the
		283	callback returns.
		284
		285	This means that the callback would be called roughly after C<$after>
		286	seconds, and then every C<$repeat> seconds. The timer does his best not
		287	to drift, but it will not invoke the timer more often then once per event
		288	loop iteration, and might drift in other cases. If that isn't acceptable,
		289	look at EV::periodic, which can provide long-term stable timers.
		290
		291	The timer is based on a monotonic clock, that is, if somebody is sitting
		292	in front of the machine while the timer is running and changes the system
		293	clock, the timer will nevertheless run (roughly) the same time.
		294
		295	The C<timer_ns> variant doesn't start (activate) the newly created watcher.
		296
		297	=item $w->set ($after, $repeat)
		298
		299	Reconfigures the watcher, see the constructor above for details. Can be at
		300	any time.
		301
		302	=item $w->again
		303
		304	Similar to the C<start> method, but has special semantics for repeating timers:
		305
		306	If the timer is active and non-repeating, it will be stopped.
		307
		308	If the timer is active and repeating, reset the timeout to occur
		309	C<$repeat> seconds after now.
		310
		311	If the timer is inactive and repeating, start it using the repeat value.
		312
		313	Otherwise do nothing.
		314
		315	This behaviour is useful when you have a timeout for some IO
		316	operation. You create a timer object with the same value for C<$after> and
		317	C<$repeat>, and then, in the read/write watcher, run the C<again> method
		318	on the timeout.
		319
		320
		321	=item $w = EV::periodic $at, $interval, $reschedule_cb, $callback
		322
		323	=item $w = EV::periodic_ns $at, $interval, $reschedule_cb, $callback
		324
		325	Similar to EV::timer, but is not based on relative timeouts but on
		326	absolute times. Apart from creating "simple" timers that trigger "at" the
		327	specified time, it can also be used for non-drifting absolute timers and
		328	more complex, cron-like, setups that are not adversely affected by time
		329	jumps (i.e. when the system clock is changed by explicit date -s or other
		330	means such as ntpd). It is also the most complex watcher type in EV.
		331
		332	It has three distinct "modes":
		333
		334	=over 4
		335
		336	=item * absolute timer ($interval = $reschedule_cb = 0)
		337
		338	This time simply fires at the wallclock time C<$at> and doesn't repeat. It
		339	will not adjust when a time jump occurs, that is, if it is to be run
		340	at January 1st 2011 then it will run when the system time reaches or
		341	surpasses this time.
		342
		343	=item * non-repeating interval timer ($interval > 0, $reschedule_cb = 0)
		344
		345	In this mode the watcher will always be scheduled to time out at the
		346	next C<$at + N * $interval> time (for some integer N) and then repeat,
		347	regardless of any time jumps.
		348
		349	This can be used to create timers that do not drift with respect to system
		350	time:
		351
		352	my $hourly = EV::periodic 0, 3600, 0, sub { print "once/hour\n" };
		353
		354	That doesn't mean there will always be 3600 seconds in between triggers,
		355	but only that the the clalback will be called when the system time shows a
		356	full hour (UTC).
		357
		358	Another way to think about it (for the mathematically inclined) is that
		359	EV::periodic will try to run the callback in this mode at the next
		360	possible time where C<$time = $at (mod $interval)>, regardless of any time
		361	jumps.
		362
		363	=item * manual reschedule mode ($reschedule_cb = coderef)
		364
		365	In this mode $interval and $at are both being ignored. Instead, each
		366	time the periodic watcher gets scheduled, the reschedule callback
		367	($reschedule_cb) will be called with the watcher as first, and the current
		368	time as second argument.
		369
		370	I<This callback MUST NOT stop or destroy this or any other periodic
		371	watcher, ever>. If you need to stop it, return 1e30 and stop it
		372	afterwards.
		373
		374	It must return the next time to trigger, based on the passed time value
		375	(that is, the lowest time value larger than to the second argument). It
		376	will usually be called just before the callback will be triggered, but
		377	might be called at other times, too.
		378
		379	This can be used to create very complex timers, such as a timer that
		380	triggers on each midnight, local time (actually 24 hours after the last
		381	midnight, to keep the example simple. If you know a way to do it correctly
		382	in about the same space (without requiring elaborate modules), drop me a
		383	note :):
		384
		385	my $daily = EV::periodic 0, 0, sub {
		386	my ($w, $now) = @_;
		387
		388	use Time::Local ();
		389	my (undef, undef, undef, $d, $m, $y) = localtime $now;
		390	86400 + Time::Local::timelocal 0, 0, 0, $d, $m, $y
		391	}, sub {
		392	print "it's midnight or likely shortly after, now\n";
		393	};
		394
40	=back	395	=back
41		396
42	=head1 BUGS	397	The C<periodic_ns> variant doesn't start (activate) the newly created watcher.
		398
		399	=item $w->set ($at, $interval, $reschedule_cb)
		400
		401	Reconfigures the watcher, see the constructor above for details. Can be at
		402	any time.
		403
		404	=item $w->again
		405
		406	Simply stops and starts the watcher again.
		407
		408
		409	=item $w = EV::signal $signal, $callback
		410
		411	=item $w = EV::signal_ns $signal, $callback
		412
		413	Call the callback when $signal is received (the signal can be specified
		414	by number or by name, just as with kill or %SIG).
		415
		416	EV will grab the signal for the process (the kernel only allows one
		417	component to receive a signal at a time) when you start a signal watcher,
		418	and removes it again when you stop it. Perl does the same when you
		419	add/remove callbacks to %SIG, so watch out.
		420
		421	You can have as many signal watchers per signal as you want.
		422
		423	The C<signal_ns> variant doesn't start (activate) the newly created watcher.
		424
		425	=item $w->set ($signal)
		426
		427	Reconfigures the watcher, see the constructor above for details. Can be at
		428	any time.
		429
		430	=item $current_signum = $w->signal
		431
		432	=item $old_signum = $w->signal ($new_signal)
		433
		434	Returns the previously set signal (always as a number not name) and
		435	optionally set a new one.
		436
		437
		438	=item $w = EV::child $pid, $callback
		439
		440	=item $w = EV::child_ns $pid, $callback
		441
		442	Call the callback when a status change for pid C<$pid> (or any pid
		443	if C<$pid> is 0) has been received. More precisely: when the process
		444	receives a SIGCHLD, EV will fetch the outstanding exit/wait status for all
		445	changed/zombie children and call the callback.
		446
		447	You can access both status and pid by using the C<rstatus> and C<rpid>
		448	methods on the watcher object.
		449
		450	You can have as many pid watchers per pid as you want.
		451
		452	The C<child_ns> variant doesn't start (activate) the newly created watcher.
		453
		454	=item $w->set ($pid)
		455
		456	Reconfigures the watcher, see the constructor above for details. Can be at
		457	any time.
		458
		459	=item $current_pid = $w->pid
		460
		461	=item $old_pid = $w->pid ($new_pid)
		462
		463	Returns the previously set process id and optionally set a new one.
		464
		465	=item $exit_status = $w->rstatus
		466
		467	Return the exit/wait status (as returned by waitpid, see the waitpid entry
		468	in perlfunc).
		469
		470	=item $pid = $w->rpid
		471
		472	Return the pid of the awaited child (useful when you have installed a
		473	watcher for all pids).
		474
		475
		476	=item $w = EV::idle $callback
		477
		478	=item $w = EV::idle_ns $callback
		479
		480	Call the callback when there are no pending io, timer/periodic, signal or
		481	child events, i.e. when the process is idle.
		482
		483	The process will not block as long as any idle watchers are active, and
		484	they will be called repeatedly until stopped.
		485
		486	The C<idle_ns> variant doesn't start (activate) the newly created watcher.
		487
		488
		489	=item $w = EV::prepare $callback
		490
		491	=item $w = EV::prepare_ns $callback
		492
		493	Call the callback just before the process would block. You can still
		494	create/modify any watchers at this point.
		495
		496	See the EV::check watcher, below, for explanations and an example.
		497
		498	The C<prepare_ns> variant doesn't start (activate) the newly created watcher.
		499
		500
		501	=item $w = EV::check $callback
		502
		503	=item $w = EV::check_ns $callback
		504
		505	Call the callback just after the process wakes up again (after it has
		506	gathered events), but before any other callbacks have been invoked.
		507
		508	This is used to integrate other event-based software into the EV
		509	mainloop: You register a prepare callback and in there, you create io and
		510	timer watchers as required by the other software. Here is a real-world
		511	example of integrating Net::SNMP (with some details left out):
		512
		513	our @snmp_watcher;
		514
		515	our $snmp_prepare = EV::prepare sub {
		516	# do nothing unless active
		517	$dispatcher->{_event_queue_h}
		518	or return;
		519
		520	# make the dispatcher handle any outstanding stuff
		521	... not shown
		522
		523	# create an IO watcher for each and every socket
		524	@snmp_watcher = (
		525	(map { EV::io $_, EV::READ, sub { } }
		526	keys %{ $dispatcher->{_descriptors} }),
		527
		528	EV::timer +($event->[Net::SNMP::Dispatcher::_ACTIVE]
		529	? $event->[Net::SNMP::Dispatcher::_TIME] - EV::now : 0),
		530	0, sub { },
		531	);
		532	};
		533
		534	The callbacks are irrelevant (and are not even being called), the
		535	only purpose of those watchers is to wake up the process as soon as
		536	one of those events occurs (socket readable, or timer timed out). The
		537	corresponding EV::check watcher will then clean up:
		538
		539	our $snmp_check = EV::check sub {
		540	# destroy all watchers
		541	@snmp_watcher = ();
		542
		543	# make the dispatcher handle any new stuff
		544	... not shown
		545	};
		546
		547	The callbacks of the created watchers will not be called as the watchers
		548	are destroyed before this cna happen (remember EV::check gets called
		549	first).
		550
		551	The C<check_ns> variant doesn't start (activate) the newly created watcher.
		552
		553	=back
		554
		555	=head1 THREADS
		556
		557	Threads are not supported by this module in any way. Perl pseudo-threads
		558	is evil stuff and must die. As soon as Perl gains real threads I will work
		559	on thread support for it.
		560
		561	=head1 FORK
		562
		563	Most of the "improved" event delivering mechanisms of modern operating
		564	systems have quite a few problems with fork(2) (to put it bluntly: it is
		565	not supported and usually destructive). Libev makes it possible to work
		566	around this by having a function that recreates the kernel state after
		567	fork in the child.
		568
		569	On non-win32 platforms, this module requires the pthread_atfork
		570	functionality to do this automatically for you. This function is quite
		571	buggy on most BSDs, though, so YMMV. The overhead for this is quite
		572	negligible, because everything the function currently does is set a flag
		573	that is checked only when the event loop gets used the next time, so when
		574	you do fork but not use EV, the overhead is minimal.
		575
		576	On win32, there is no notion of fork so all this doesn't apply, of course.
43		577
44	=cut	578	=cut
45		579
46	our $NPRI = 4;	580	our $DIED = sub {
47	our $BASE = init;	581	warn "EV: error in callback (ignoring): $@";
48	priority_init $NPRI;	582	};
		583
		584	default_loop
		585	or die 'EV: cannot initialise libev backend. bad $ENV{LIBEV_METHODS}?';
49		586
50	1;	587	1;
		588
		589	=head1 SEE ALSO
		590
		591	L<EV::DNS>.
51		592
52	=head1 AUTHOR	593	=head1 AUTHOR
53		594
54	Marc Lehmann <schmorp@schmorp.de>	595	Marc Lehmann <schmorp@schmorp.de>
55	http://home.schmorp.de/	596	http://home.schmorp.de/

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Comparing EV/EV.pm (file contents): Revision 1.1 by root, Fri Oct 26 16:50:05 2007 UTC vs. Revision 1.48 by root, Fri Nov 23 13:09:02 2007 UTC

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Comparing EV/EV.pm (file contents):
Revision 1.1 by root, Fri Oct 26 16:50:05 2007 UTC vs.
Revision 1.48 by root, Fri Nov 23 13:09:02 2007 UTC