[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 1.31 by root, Thu Nov 8 02:21:02 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, 1, sub {
		16	warn "is called roughly every 2s (repeat = 1)";
		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 get the watcher object 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	my $w = EV::signal 3, sub {
		39	warn "sigquit received (this is GNU/Linux, right?)\n";
		40	};
		41
		42	# CHILD/PID STATUS CHANGES
		43
		44	my $w = EV::child 666, sub {
		45	my ($w, $revents) = @_;
		46	# my $pid = $w->rpid;
		47	my $status = $w->rstatus;
		48	};
		49
		50	# MAINLOOP
		51	EV::loop; # loop until EV::loop_done is called
		52	EV::loop EV::LOOP_ONESHOT; # block until at least one event could be handled
		53	EV::loop EV::LOOP_NONBLOCK; # try to handle same events, but do not block
8		54
9	=head1 DESCRIPTION	55	=head1 DESCRIPTION
10		56
11	This module provides an interface to libevent	57	This module provides an interface to libev
12	(L<http://monkey.org/~provos/libevent/>).	58	(L<http://software.schmorp.de/pkg/libev.html>).
13		59
14	=cut	60	=cut
15		61
16	package EV;	62	package EV;
17		63
18	use strict;	64	use strict;
19		65
20	BEGIN {	66	BEGIN {
21	our $VERSION = '0.01';	67	our $VERSION = '0.51';
22	use XSLoader;	68	use XSLoader;
23	XSLoader::load "EV", $VERSION;	69	XSLoader::load "EV", $VERSION;
24	}	70	}
25		71
26	=head1 FUNCTIONAL INTERFACE	72	@EV::Io::ISA =
		73	@EV::Timer::ISA =
		74	@EV::Periodic::ISA =
		75	@EV::Signal::ISA =
		76	@EV::Idle::ISA =
		77	@EV::Prepare::ISA =
		78	@EV::Check::ISA =
		79	@EV::Child::ISA = "EV::Watcher";
		80
		81	=head1 BASIC INTERFACE
27		82
28	=over 4	83	=over 4
29		84
		85	=item $EV::DIED
		86
		87	Must contain a reference to a function that is called when a callback
		88	throws an exception (with $@ containing thr error). The default prints an
		89	informative message and continues.
		90
		91	If this callback throws an exception it will be silently ignored.
		92
		93	=item $time = EV::time
		94
		95	Returns the current time in (fractional) seconds since the epoch.
		96
		97	=item $time = EV::now
		98
		99	Returns the time the last event loop iteration has been started. This
		100	is the time that (relative) timers are based on, and refering to it is
		101	usually faster then calling EV::time.
		102
		103	=item $method = EV::ev_method
		104
		105	Returns an integer describing the backend used by libev (EV::METHOD_SELECT
		106	or EV::METHOD_EPOLL).
		107
		108	=item EV::loop [$flags]
		109
		110	Begin checking for events and calling callbacks. It returns when a
		111	callback calls EV::loop_done.
		112
		113	The $flags argument can be one of the following:
		114
		115	0 as above
		116	EV::LOOP_ONESHOT block at most once (wait, but do not loop)
		117	EV::LOOP_NONBLOCK do not block at all (fetch/handle events but do not wait)
		118
		119	=item EV::loop_done [$how]
		120
		121	When called with no arguments or an argument of 1, makes the innermost
		122	call to EV::loop return.
		123
		124	When called with an agrument of 2, all calls to EV::loop will return as
		125	fast as possible.
		126
30	=back	127	=back
31		128
		129	=head2 WATCHER
32		130
33	=head1 OBJECT-ORIENTED INTERFACE	131	A watcher is an object that gets created to record your interest in some
		132	event. For instance, if you want to wait for STDIN to become readable, you
		133	would create an EV::io watcher for that:
34		134
35	The object oriented interface lets you configure your own encoding or	135	my $watcher = EV::io *STDIN, EV::READ, sub {
36	decoding style, within the limits of supported formats.	136	my ($watcher, $revents) = @_;
		137	warn "yeah, STDIN should not be readable without blocking!\n"
		138	};
		139
		140	All watchers can be active (waiting for events) or inactive (paused). Only
		141	active watchers will have their callbacks invoked. All callbacks will be
		142	called with at least two arguments: the watcher and a bitmask of received
		143	events.
		144
		145	Each watcher type has its associated bit in revents, so you can use the
		146	same callback for multiple watchers. The event mask is named after the
		147	type, i..e. EV::child sets EV::CHILD, EV::prepare sets EV::PREPARE,
		148	EV::periodic sets EV::PERIODIC and so on, with the exception of IO events
		149	(which can set both EV::READ and EV::WRITE bits), and EV::timer (which
		150	uses EV::TIMEOUT).
		151
		152	In the rare case where one wants to create a watcher but not start it at
		153	the same time, each constructor has a variant with a trailing C<_ns> in
		154	its name, e.g. EV::io has a non-starting variant EV::io_ns and so on.
		155
		156	Please note that a watcher will automatically be stopped when the watcher
		157	object is destroyed, so you I<need> to keep the watcher objects returned by
		158	the constructors.
		159
		160	Also, all methods changing some aspect of a watcher (->set, ->priority,
		161	->fh and so on) automatically stop and start it again if it is active,
		162	which means pending events get lost.
		163
		164	=head2 WATCHER TYPES
		165
		166	Now lets move to the existing watcher types and asociated methods.
		167
		168	The following methods are available for all watchers. Then followes a
		169	description of each watcher constructor (EV::io, EV::timer, EV::periodic,
		170	EV::signal, EV::child, EV::idle, EV::prepare and EV::check), followed by
		171	any type-specific methods (if any).
37		172
38	=over 4	173	=over 4
39		174
		175	=item $w->start
		176
		177	Starts a watcher if it isn't active already. Does nothing to an already
		178	active watcher. By default, all watchers start out in the active state
		179	(see the description of the C<_ns> variants if you need stopped watchers).
		180
		181	=item $w->stop
		182
		183	Stop a watcher if it is active. Also clear any pending events (events that
		184	have been received but that didn't yet result in a callback invocation),
		185	regardless of wether the watcher was active or not.
		186
		187	=item $bool = $w->is_active
		188
		189	Returns true if the watcher is active, false otherwise.
		190
		191	=item $current_data = $w->data
		192
		193	=item $old_data = $w->data ($new_data)
		194
		195	Queries a freely usable data scalar on the watcher and optionally changes
		196	it. This is a way to associate custom data with a watcher:
		197
		198	my $w = EV::timer 60, 0, sub {
		199	warn $_[0]->data;
		200	};
		201	$w->data ("print me!");
		202
		203	=item $current_cb = $w->cb
		204
		205	=item $old_cb = $w->cb ($new_cb)
		206
		207	Queries the callback on the watcher and optionally changes it. You can do
		208	this at any time without the watcher restarting.
		209
		210	=item $current_priority = $w->priority
		211
		212	=item $old_priority = $w->priority ($new_priority)
		213
		214	Queries the priority on the watcher and optionally changes it. Pending
		215	watchers with higher priority will be invoked first. The valid range of
		216	priorities lies between EV::MAXPRI (default 2) and EV::MINPRI (default
		217	-2). If the priority is outside this range it will automatically be
		218	normalised to the nearest valid priority.
		219
		220	The default priority of any newly-created weatcher is 0.
		221
		222	=item $w->trigger ($revents)
		223
		224	Call the callback now with the given event mask.
		225
		226
		227	=item $w = EV::io $fileno_or_fh, $eventmask, $callback
		228
		229	=item $w = EV::io_ns $fileno_or_fh, $eventmask, $callback
		230
		231	As long as the returned watcher object is alive, call the C<$callback>
		232	when the events specified in C<$eventmask>.
		233
		234	The $eventmask can be one or more of these constants ORed together:
		235
		236	EV::READ wait until read() wouldn't block anymore
		237	EV::WRITE wait until write() wouldn't block anymore
		238
		239	The C<io_ns> variant doesn't start (activate) the newly created watcher.
		240
		241	=item $w->set ($fileno_or_fh, $eventmask)
		242
		243	Reconfigures the watcher, see the constructor above for details. Can be
		244	called at any time.
		245
		246	=item $current_fh = $w->fh
		247
		248	=item $old_fh = $w->fh ($new_fh)
		249
		250	Returns the previously set filehandle and optionally set a new one.
		251
		252	=item $current_eventmask = $w->events
		253
		254	=item $old_eventmask = $w->events ($new_eventmask)
		255
		256	Returns the previously set event mask and optionally set a new one.
		257
		258
		259	=item $w = EV::timer $after, $repeat, $callback
		260
		261	=item $w = EV::timer_ns $after, $repeat, $callback
		262
		263	Calls the callback after C<$after> seconds. If C<$repeat> is non-zero,
		264	the timer will be restarted (with the $repeat value as $after) after the
		265	callback returns.
		266
		267	This means that the callback would be called roughly after C<$after>
		268	seconds, and then every C<$repeat> seconds. "Roughly" because the time of
		269	callback processing is not taken into account, so the timer will slowly
		270	drift. If that isn't acceptable, look at EV::periodic.
		271
		272	The timer is based on a monotonic clock, that is if somebody is sitting
		273	in front of the machine while the timer is running and changes the system
		274	clock, the timer will nevertheless run (roughly) the same time.
		275
		276	The C<timer_ns> variant doesn't start (activate) the newly created watcher.
		277
		278	=item $w->set ($after, $repeat)
		279
		280	Reconfigures the watcher, see the constructor above for details. Can be at
		281	any time.
		282
		283	=item $w->again
		284
		285	Similar to the C<start> method, but has special semantics for repeating timers:
		286
		287	If the timer is active and repeating, reset the timeout to occur
		288	C<$repeat> seconds after now.
		289
		290	If the timer is active and non-repeating, it will be stopped.
		291
		292	If the timer is in active and repeating, start it.
		293
		294	Otherwise do nothing.
		295
		296	This behaviour is useful when you have a timeout for some IO
		297	operation. You create a timer object with the same value for C<$after> and
		298	C<$repeat>, and then, in the read/write watcher, run the C<again> method
		299	on the timeout.
		300
		301
		302	=item $w = EV::periodic $at, $interval, $reschedule_cb, $callback
		303
		304	=item $w = EV::periodic_ns $at, $interval, $reschedule_cb, $callback
		305
		306	Similar to EV::timer, but is not based on relative timeouts but on
		307	absolute times. Apart from creating "simple" timers that trigger "at" the
		308	specified time, it can also be used for non-drifting absolute timers and
		309	more complex, cron-like, setups that are not adversely affected by time
		310	jumps (i.e. when the system clock is changed by explicit date -s or other
		311	means such as ntpd). It is also the most complex watcher type in EV.
		312
		313	It has three distinct "modes":
		314
		315	=over 4
		316
		317	=item * absolute timer ($interval = $reschedule_cb = 0)
		318
		319	This time simply fires at the wallclock time C<$at> and doesn't repeat. It
		320	will not adjust when a time jump occurs, that is, if it is to be run
		321	at January 1st 2011 then it will run when the system time reaches or
		322	surpasses this time.
		323
		324	=item * non-repeating interval timer ($interval > 0, $reschedule_cb = 0)
		325
		326	In this mode the watcher will always be scheduled to time out at the
		327	next C<$at + N * $interval> time (for some integer N) and then repeat,
		328	regardless of any time jumps.
		329
		330	This can be used to create timers that do not drift with respect to system
		331	time:
		332
		333	my $hourly = EV::periodic 0, 3600, 0, sub { print "once/hour\n" };
		334
		335	That doesn't mean there will always be 3600 seconds in between triggers,
		336	but only that the the clalback will be called when the system time shows a
		337	full hour (UTC).
		338
		339	Another way to think about it (for the mathematically inclined) is that
		340	EV::periodic will try to run the callback in this mode at the next
		341	possible time where C<$time = $at (mod $interval)>, regardless of any time
		342	jumps.
		343
		344	=item * manual reschedule mode ($reschedule_cb = coderef)
		345
		346	In this mode $interval and $at are both being ignored. Instead, each time
		347	the periodic watcher gets scheduled, the first callback ($reschedule_cb)
		348	will be called with the watcher as first, and the current time as second
		349	argument.
		350
		351	I<This callback MUST NOT stop or destroy this or any other periodic
		352	watcher, ever>. If you need to stop it, return 1e30 and stop it
		353	afterwards.
		354
		355	It must return the next time to trigger, based on the passed time value
		356	(that is, the lowest time value larger than to the second argument). It
		357	will usually be called just before the callback will be triggered, but
		358	might be called at other times, too.
		359
		360	This can be used to create very complex timers, such as a timer that
		361	triggers on each midnight, local time (actually 24 hours after the last
		362	midnight, to keep the example simple. If you know a way to do it correctly
		363	in about the same space (without requiring elaborate modules), drop me a
		364	note :):
		365
		366	my $daily = EV::periodic 0, 0, sub {
		367	my ($w, $now) = @_;
		368
		369	use Time::Local ();
		370	my (undef, undef, undef, $d, $m, $y) = localtime $now;
		371	86400 + Time::Local::timelocal 0, 0, 0, $d, $m, $y
		372	}, sub {
		373	print "it's midnight or likely shortly after, now\n";
		374	};
		375
40	=back	376	=back
41		377
42	=head1 BUGS	378	The C<periodic_ns> variant doesn't start (activate) the newly created watcher.
		379
		380	=item $w->set ($at, $interval, $reschedule_cb)
		381
		382	Reconfigures the watcher, see the constructor above for details. Can be at
		383	any time.
		384
		385	=item $w->again
		386
		387	Simply stops and starts the watcher again.
		388
		389
		390	=item $w = EV::signal $signal, $callback
		391
		392	=item $w = EV::signal_ns $signal, $callback
		393
		394	Call the callback when $signal is received (the signal can be specified
		395	by number or by name, just as with kill or %SIG).
		396
		397	EV will grab the signal for the process (the kernel only allows one
		398	component to receive a signal at a time) when you start a signal watcher,
		399	and removes it again when you stop it. Perl does the same when you
		400	add/remove callbacks to %SIG, so watch out.
		401
		402	You can have as many signal watchers per signal as you want.
		403
		404	The C<signal_ns> variant doesn't start (activate) the newly created watcher.
		405
		406	=item $w->set ($signal)
		407
		408	Reconfigures the watcher, see the constructor above for details. Can be at
		409	any time.
		410
		411	=item $current_signum = $w->signal
		412
		413	=item $old_signum = $w->signal ($new_signal)
		414
		415	Returns the previously set signal (always as a number not name) and
		416	optionally set a new one.
		417
		418
		419	=item $w = EV::child $pid, $callback
		420
		421	=item $w = EV::child_ns $pid, $callback
		422
		423	Call the callback when a status change for pid C<$pid> (or any pid
		424	if C<$pid> is 0) has been received. More precisely: when the process
		425	receives a SIGCHLD, EV will fetch the outstanding exit/wait status for all
		426	changed/zombie children and call the callback.
		427
		428	You can access both status and pid by using the C<rstatus> and C<rpid>
		429	methods on the watcher object.
		430
		431	You can have as many pid watchers per pid as you want.
		432
		433	The C<child_ns> variant doesn't start (activate) the newly created watcher.
		434
		435	=item $w->set ($pid)
		436
		437	Reconfigures the watcher, see the constructor above for details. Can be at
		438	any time.
		439
		440	=item $current_pid = $w->pid
		441
		442	=item $old_pid = $w->pid ($new_pid)
		443
		444	Returns the previously set process id and optionally set a new one.
		445
		446	=item $exit_status = $w->rstatus
		447
		448	Return the exit/wait status (as returned by waitpid, see the waitpid entry
		449	in perlfunc).
		450
		451	=item $pid = $w->rpid
		452
		453	Return the pid of the awaited child (useful when you have installed a
		454	watcher for all pids).
		455
		456
		457	=item $w = EV::idle $callback
		458
		459	=item $w = EV::idle_ns $callback
		460
		461	Call the callback when there are no pending io, timer/periodic, signal or
		462	child events, i.e. when the process is idle.
		463
		464	The process will not block as long as any idle watchers are active, and
		465	they will be called repeatedly until stopped.
		466
		467	The C<idle_ns> variant doesn't start (activate) the newly created watcher.
		468
		469
		470	=item $w = EV::prepare $callback
		471
		472	=item $w = EV::prepare_ns $callback
		473
		474	Call the callback just before the process would block. You can still
		475	create/modify any watchers at this point.
		476
		477	See the EV::check watcher, below, for explanations and an example.
		478
		479	The C<prepare_ns> variant doesn't start (activate) the newly created watcher.
		480
		481
		482	=item $w = EV::check $callback
		483
		484	=item $w = EV::check_ns $callback
		485
		486	Call the callback just after the process wakes up again (after it has
		487	gathered events), but before any other callbacks have been invoked.
		488
		489	This is used to integrate other event-based software into the EV
		490	mainloop: You register a prepare callback and in there, you create io and
		491	timer watchers as required by the other software. Here is a real-world
		492	example of integrating Net::SNMP (with some details left out):
		493
		494	our @snmp_watcher;
		495
		496	our $snmp_prepare = EV::prepare sub {
		497	# do nothing unless active
		498	$dispatcher->{_event_queue_h}
		499	or return;
		500
		501	# make the dispatcher handle any outstanding stuff
		502
		503	# create an IO watcher for each and every socket
		504	@snmp_watcher = (
		505	(map { EV::io $_, EV::READ, sub { } }
		506	keys %{ $dispatcher->{_descriptors} }),
		507	);
		508
		509	# if there are any timeouts, also create a timer
		510	push @snmp_watcher, EV::timer $event->[Net::SNMP::Dispatcher::_TIME] - EV::now, 0, sub { }
		511	if $event->[Net::SNMP::Dispatcher::_ACTIVE];
		512	};
		513
		514	The callbacks are irrelevant, the only purpose of those watchers is
		515	to wake up the process as soon as one of those events occurs (socket
		516	readable, or timer timed out). The corresponding EV::check watcher will then
		517	clean up:
		518
		519	our $snmp_check = EV::check sub {
		520	# destroy all watchers
		521	@snmp_watcher = ();
		522
		523	# make the dispatcher handle any new stuff
		524	};
		525
		526	The callbacks of the created watchers will not be called as the watchers
		527	are destroyed before this cna happen (remember EV::check gets called
		528	first).
		529
		530	The C<check_ns> variant doesn't start (activate) the newly created watcher.
		531
		532	=back
		533
		534	=head1 THREADS
		535
		536	Threads are not supported by this in any way. Perl pseudo-threads is evil
		537	stuff and must die.
43		538
44	=cut	539	=cut
45		540
46	our $NPRI = 4;	541	our $DIED = sub {
47	our $BASE = init;	542	warn "EV: error in callback (ignoring): $@";
48	priority_init $NPRI;	543	};
		544
		545	default_loop
		546	or die 'EV: cannot initialise libev backend. bad $ENV{LIBEV_METHODS}?';
		547
		548	push @AnyEvent::REGISTRY, [EV => "EV::AnyEvent"];
49		549
50	1;	550	1;
		551
		552	=head1 SEE ALSO
		553
		554	L<EV::DNS>, L<EV::AnyEvent>.
51		555
52	=head1 AUTHOR	556	=head1 AUTHOR
53		557
54	Marc Lehmann <schmorp@schmorp.de>	558	Marc Lehmann <schmorp@schmorp.de>
55	http://home.schmorp.de/	559	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 1.31 by root, Thu Nov 8 02:21:02 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 1.31 by root, Thu Nov 8 02:21:02 2007 UTC