[ViewVC] Diff of: cvs/AnyEvent/lib/AnyEvent.pm

Comparing AnyEvent/lib/AnyEvent.pm (file contents):
Revision 1.107 by root, Tue May 6 12:15:50 2008 UTC vs.
Revision 1.133 by root, Sun May 25 03:44:03 2008 UTC

…		…
1	=head1 NAME	1	=head1 => NAME
2		2
3	AnyEvent - provide framework for multiple event loops	3	AnyEvent - provide framework for multiple event loops
4		4
5	EV, Event, Coro::EV, Coro::Event, Glib, Tk, Perl, Event::Lib, Qt, POE - various supported event loops	5	EV, Event, Glib, Tk, Perl, Event::Lib, Qt, POE - various supported event loops
6		6
7	=head1 SYNOPSIS	7	=head1 SYNOPSIS
8		8
9	use AnyEvent;	9	use AnyEvent;
10		10
15	my $w = AnyEvent->timer (after => $seconds, cb => sub {	15	my $w = AnyEvent->timer (after => $seconds, cb => sub {
16	...	16	...
17	});	17	});
18		18
19	my $w = AnyEvent->condvar; # stores whether a condition was flagged	19	my $w = AnyEvent->condvar; # stores whether a condition was flagged
		20	$w->send; # wake up current and all future recv's
20	$w->wait; # enters "main loop" till $condvar gets ->send	21	$w->recv; # enters "main loop" till $condvar gets ->send
21	$w->send; # wake up current and all future wait's
22		22
23	=head1 WHY YOU SHOULD USE THIS MODULE (OR NOT)	23	=head1 WHY YOU SHOULD USE THIS MODULE (OR NOT)
24		24
25	Glib, POE, IO::Async, Event... CPAN offers event models by the dozen	25	Glib, POE, IO::Async, Event... CPAN offers event models by the dozen
26	nowadays. So what is different about AnyEvent?	26	nowadays. So what is different about AnyEvent?
…		…
57	as those use one of the supported event loops. It is trivial to add new	57	as those use one of the supported event loops. It is trivial to add new
58	event loops to AnyEvent, too, so it is future-proof).	58	event loops to AnyEvent, too, so it is future-proof).
59		59
60	In addition to being free of having to use I<the one and only true event	60	In addition to being free of having to use I<the one and only true event
61	model>, AnyEvent also is free of bloat and policy: with POE or similar	61	model>, AnyEvent also is free of bloat and policy: with POE or similar
62	modules, you get an enourmous amount of code and strict rules you have to	62	modules, you get an enormous amount of code and strict rules you have to
63	follow. AnyEvent, on the other hand, is lean and up to the point, by only	63	follow. AnyEvent, on the other hand, is lean and up to the point, by only
64	offering the functionality that is necessary, in as thin as a wrapper as	64	offering the functionality that is necessary, in as thin as a wrapper as
65	technically possible.	65	technically possible.
66		66
67	Of course, if you want lots of policy (this can arguably be somewhat	67	Of course, if you want lots of policy (this can arguably be somewhat
…		…
78	The interface itself is vaguely similar, but not identical to the L<Event>	78	The interface itself is vaguely similar, but not identical to the L<Event>
79	module.	79	module.
80		80
81	During the first call of any watcher-creation method, the module tries	81	During the first call of any watcher-creation method, the module tries
82	to detect the currently loaded event loop by probing whether one of the	82	to detect the currently loaded event loop by probing whether one of the
83	following modules is already loaded: L<Coro::EV>, L<Coro::Event>, L<EV>,	83	following modules is already loaded: L<EV>,
84	L<Event>, L<Glib>, L<AnyEvent::Impl::Perl>, L<Tk>, L<Event::Lib>, L<Qt>,	84	L<Event>, L<Glib>, L<AnyEvent::Impl::Perl>, L<Tk>, L<Event::Lib>, L<Qt>,
85	L<POE>. The first one found is used. If none are found, the module tries	85	L<POE>. The first one found is used. If none are found, the module tries
86	to load these modules (excluding Tk, Event::Lib, Qt and POE as the pure perl	86	to load these modules (excluding Tk, Event::Lib, Qt and POE as the pure perl
87	adaptor should always succeed) in the order given. The first one that can	87	adaptor should always succeed) in the order given. The first one that can
88	be successfully loaded will be used. If, after this, still none could be	88	be successfully loaded will be used. If, after this, still none could be
…		…
108		108
109	=head1 WATCHERS	109	=head1 WATCHERS
110		110
111	AnyEvent has the central concept of a I<watcher>, which is an object that	111	AnyEvent has the central concept of a I<watcher>, which is an object that
112	stores relevant data for each kind of event you are waiting for, such as	112	stores relevant data for each kind of event you are waiting for, such as
113	the callback to call, the filehandle to watch, etc.	113	the callback to call, the file handle to watch, etc.
114		114
115	These watchers are normal Perl objects with normal Perl lifetime. After	115	These watchers are normal Perl objects with normal Perl lifetime. After
116	creating a watcher it will immediately "watch" for events and invoke the	116	creating a watcher it will immediately "watch" for events and invoke the
117	callback when the event occurs (of course, only when the event model	117	callback when the event occurs (of course, only when the event model
118	is in control).	118	is in control).
…		…
237		237
238	Although the callback might get passed parameters, their value and	238	Although the callback might get passed parameters, their value and
239	presence is undefined and you cannot rely on them. Portable AnyEvent	239	presence is undefined and you cannot rely on them. Portable AnyEvent
240	callbacks cannot use arguments passed to signal watcher callbacks.	240	callbacks cannot use arguments passed to signal watcher callbacks.
241		241
242	Multiple signal occurances can be clumped together into one callback	242	Multiple signal occurrences can be clumped together into one callback
243	invocation, and callback invocation will be synchronous. synchronous means	243	invocation, and callback invocation will be synchronous. Synchronous means
244	that it might take a while until the signal gets handled by the process,	244	that it might take a while until the signal gets handled by the process,
245	but it is guarenteed not to interrupt any other callbacks.	245	but it is guaranteed not to interrupt any other callbacks.
246		246
247	The main advantage of using these watchers is that you can share a signal	247	The main advantage of using these watchers is that you can share a signal
248	between multiple watchers.	248	between multiple watchers.
249		249
250	This watcher might use C<%SIG>, so programs overwriting those signals	250	This watcher might use C<%SIG>, so programs overwriting those signals
…		…
278	C<fork> the child (alternatively, you can call C<AnyEvent::detect>).	278	C<fork> the child (alternatively, you can call C<AnyEvent::detect>).
279		279
280	Example: fork a process and wait for it	280	Example: fork a process and wait for it
281		281
282	my $done = AnyEvent->condvar;	282	my $done = AnyEvent->condvar;
283
284	AnyEvent::detect; # force event module to be initialised
285		283
286	my $pid = fork or exit 5;	284	my $pid = fork or exit 5;
287		285
288	my $w = AnyEvent->child (	286	my $w = AnyEvent->child (
289	pid => $pid,	287	pid => $pid,
…		…
293	$done->send;	291	$done->send;
294	},	292	},
295	);	293	);
296		294
297	# do something else, then wait for process exit	295	# do something else, then wait for process exit
298	$done->wait;	296	$done->recv;
299		297
300	=head2 CONDITION VARIABLES	298	=head2 CONDITION VARIABLES
301		299
302	If you are familiar with some event loops you will know that all of them	300	If you are familiar with some event loops you will know that all of them
303	require you to run some blocking "loop", "run" or similar function that	301	require you to run some blocking "loop", "run" or similar function that
…		…
312	Condition variables can be created by calling the C<< AnyEvent->condvar	310	Condition variables can be created by calling the C<< AnyEvent->condvar
313	>> method, usually without arguments. The only argument pair allowed is	311	>> method, usually without arguments. The only argument pair allowed is
314	C<cb>, which specifies a callback to be called when the condition variable	312	C<cb>, which specifies a callback to be called when the condition variable
315	becomes true.	313	becomes true.
316		314
317	After creation, the conditon variable is "false" until it becomes "true"	315	After creation, the condition variable is "false" until it becomes "true"
318	by calling the C<send> method.	316	by calling the C<send> method (or calling the condition variable as if it
		317	were a callback).
319		318
320	Condition variables are similar to callbacks, except that you can	319	Condition variables are similar to callbacks, except that you can
321	optionally wait for them. They can also be called merge points - points	320	optionally wait for them. They can also be called merge points - points
322	in time where multiple outstandign events have been processed. And yet	321	in time where multiple outstanding events have been processed. And yet
323	another way to call them is transations - each condition variable can be	322	another way to call them is transactions - each condition variable can be
324	used to represent a transaction, which finishes at some point and delivers	323	used to represent a transaction, which finishes at some point and delivers
325	a result.	324	a result.
326		325
327	Condition variables are very useful to signal that something has finished,	326	Condition variables are very useful to signal that something has finished,
328	for example, if you write a module that does asynchronous http requests,	327	for example, if you write a module that does asynchronous http requests,
329	then a condition variable would be the ideal candidate to signal the	328	then a condition variable would be the ideal candidate to signal the
330	availability of results. The user can either act when the callback is	329	availability of results. The user can either act when the callback is
331	called or can synchronously C<< ->wait >> for the results.	330	called or can synchronously C<< ->recv >> for the results.
332		331
333	You can also use them to simulate traditional event loops - for example,	332	You can also use them to simulate traditional event loops - for example,
334	you can block your main program until an event occurs - for example, you	333	you can block your main program until an event occurs - for example, you
335	could C<< ->wait >> in your main program until the user clicks the Quit	334	could C<< ->recv >> in your main program until the user clicks the Quit
336	button of your app, which would C<< ->send >> the "quit" event.	335	button of your app, which would C<< ->send >> the "quit" event.
337		336
338	Note that condition variables recurse into the event loop - if you have	337	Note that condition variables recurse into the event loop - if you have
339	two pieces of code that call C<< ->wait >> in a round-robbin fashion, you	338	two pieces of code that call C<< ->recv >> in a round-robin fashion, you
340	lose. Therefore, condition variables are good to export to your caller, but	339	lose. Therefore, condition variables are good to export to your caller, but
341	you should avoid making a blocking wait yourself, at least in callbacks,	340	you should avoid making a blocking wait yourself, at least in callbacks,
342	as this asks for trouble.	341	as this asks for trouble.
343		342
344	Condition variables are represented by hash refs in perl, and the keys	343	Condition variables are represented by hash refs in perl, and the keys
…		…
349		348
350	There are two "sides" to a condition variable - the "producer side" which	349	There are two "sides" to a condition variable - the "producer side" which
351	eventually calls C<< -> send >>, and the "consumer side", which waits	350	eventually calls C<< -> send >>, and the "consumer side", which waits
352	for the send to occur.	351	for the send to occur.
353		352
354	Example:	353	Example: wait for a timer.
355		354
356	# wait till the result is ready	355	# wait till the result is ready
357	my $result_ready = AnyEvent->condvar;	356	my $result_ready = AnyEvent->condvar;
358		357
359	# do something such as adding a timer	358	# do something such as adding a timer
…		…
365	cb => sub { $result_ready->send },	364	cb => sub { $result_ready->send },
366	);	365	);
367		366
368	# this "blocks" (while handling events) till the callback	367	# this "blocks" (while handling events) till the callback
369	# calls send	368	# calls send
370	$result_ready->wait;	369	$result_ready->recv;
		370
		371	Example: wait for a timer, but take advantage of the fact that
		372	condition variables are also code references.
		373
		374	my $done = AnyEvent->condvar;
		375	my $delay = AnyEvent->timer (after => 5, cb => $done);
		376	$done->recv;
371		377
372	=head3 METHODS FOR PRODUCERS	378	=head3 METHODS FOR PRODUCERS
373		379
374	These methods should only be used by the producing side, i.e. the	380	These methods should only be used by the producing side, i.e. the
375	code/module that eventually sends the signal. Note that it is also	381	code/module that eventually sends the signal. Note that it is also
…		…
378		384
379	=over 4	385	=over 4
380		386
381	=item $cv->send (...)	387	=item $cv->send (...)
382		388
383	Flag the condition as ready - a running C<< ->wait >> and all further	389	Flag the condition as ready - a running C<< ->recv >> and all further
384	calls to C<wait> will (eventually) return after this method has been	390	calls to C<recv> will (eventually) return after this method has been
385	called. If nobody is waiting the send will be remembered.	391	called. If nobody is waiting the send will be remembered.
386		392
387	If a callback has been set on the condition variable, it is called	393	If a callback has been set on the condition variable, it is called
388	immediately from within send.	394	immediately from within send.
389		395
390	Any arguments passed to the C<send> call will be returned by all	396	Any arguments passed to the C<send> call will be returned by all
391	future C<< ->wait >> calls.	397	future C<< ->recv >> calls.
		398
		399	Condition variables are overloaded so one can call them directly (as a
		400	code reference). Calling them directly is the same as calling C<send>.
392		401
393	=item $cv->croak ($error)	402	=item $cv->croak ($error)
394		403
395	Similar to send, but causes all call's wait C<< ->wait >> to invoke	404	Similar to send, but causes all call's to C<< ->recv >> to invoke
396	C<Carp::croak> with the given error message/object/scalar.	405	C<Carp::croak> with the given error message/object/scalar.
397		406
398	This can be used to signal any errors to the condition variable	407	This can be used to signal any errors to the condition variable
399	user/consumer.	408	user/consumer.
400		409
401	=item $cv->begin ([group callback])	410	=item $cv->begin ([group callback])
402		411
403	=item $cv->end	412	=item $cv->end
		413
		414	These two methods are EXPERIMENTAL and MIGHT CHANGE.
404		415
405	These two methods can be used to combine many transactions/events into	416	These two methods can be used to combine many transactions/events into
406	one. For example, a function that pings many hosts in parallel might want	417	one. For example, a function that pings many hosts in parallel might want
407	to use a condition variable for the whole process.	418	to use a condition variable for the whole process.
408		419
…		…
443	doesn't execute once).	454	doesn't execute once).
444		455
445	This is the general pattern when you "fan out" into multiple subrequests:	456	This is the general pattern when you "fan out" into multiple subrequests:
446	use an outer C<begin>/C<end> pair to set the callback and ensure C<end>	457	use an outer C<begin>/C<end> pair to set the callback and ensure C<end>
447	is called at least once, and then, for each subrequest you start, call	458	is called at least once, and then, for each subrequest you start, call
448	C<begin> and for eahc subrequest you finish, call C<end>.	459	C<begin> and for each subrequest you finish, call C<end>.
449		460
450	=back	461	=back
451		462
452	=head3 METHODS FOR CONSUMERS	463	=head3 METHODS FOR CONSUMERS
453		464
454	These methods should only be used by the consuming side, i.e. the	465	These methods should only be used by the consuming side, i.e. the
455	code awaits the condition.	466	code awaits the condition.
456		467
457	=over 4	468	=over 4
458		469
459	=item $cv->wait	470	=item $cv->recv
460		471
461	Wait (blocking if necessary) until the C<< ->send >> or C<< ->croak	472	Wait (blocking if necessary) until the C<< ->send >> or C<< ->croak
462	>> methods have been called on c<$cv>, while servicing other watchers	473	>> methods have been called on c<$cv>, while servicing other watchers
463	normally.	474	normally.
464		475
…		…
475	(programs might want to do that to stay interactive), so I<if you are	486	(programs might want to do that to stay interactive), so I<if you are
476	using this from a module, never require a blocking wait>, but let the	487	using this from a module, never require a blocking wait>, but let the
477	caller decide whether the call will block or not (for example, by coupling	488	caller decide whether the call will block or not (for example, by coupling
478	condition variables with some kind of request results and supporting	489	condition variables with some kind of request results and supporting
479	callbacks so the caller knows that getting the result will not block,	490	callbacks so the caller knows that getting the result will not block,
480	while still suppporting blocking waits if the caller so desires).	491	while still supporting blocking waits if the caller so desires).
481		492
482	Another reason I<never> to C<< ->wait >> in a module is that you cannot	493	Another reason I<never> to C<< ->recv >> in a module is that you cannot
483	sensibly have two C<< ->wait >>'s in parallel, as that would require	494	sensibly have two C<< ->recv >>'s in parallel, as that would require
484	multiple interpreters or coroutines/threads, none of which C<AnyEvent>	495	multiple interpreters or coroutines/threads, none of which C<AnyEvent>
485	can supply (the coroutine-aware backends L<AnyEvent::Impl::CoroEV> and	496	can supply.
486	L<AnyEvent::Impl::CoroEvent> explicitly support concurrent C<< ->wait >>'s
487	from different coroutines, however).
488		497
		498	The L<Coro> module, however, I<can> and I<does> supply coroutines and, in
		499	fact, L<Coro::AnyEvent> replaces AnyEvent's condvars by coroutine-safe
		500	versions and also integrates coroutines into AnyEvent, making blocking
		501	C<< ->recv >> calls perfectly safe as long as they are done from another
		502	coroutine (one that doesn't run the event loop).
		503
489	You can ensure that C<< -wait >> never blocks by setting a callback and	504	You can ensure that C<< -recv >> never blocks by setting a callback and
490	only calling C<< ->wait >> from within that callback (or at a later	505	only calling C<< ->recv >> from within that callback (or at a later
491	time). This will work even when the event loop does not support blocking	506	time). This will work even when the event loop does not support blocking
492	waits otherwise.	507	waits otherwise.
493		508
494	=item $bool = $cv->ready	509	=item $bool = $cv->ready
495		510
…		…
500		515
501	This is a mutator function that returns the callback set and optionally	516	This is a mutator function that returns the callback set and optionally
502	replaces it before doing so.	517	replaces it before doing so.
503		518
504	The callback will be called when the condition becomes "true", i.e. when	519	The callback will be called when the condition becomes "true", i.e. when
505	C<send> or C<croak> are called. Calling C<wait> inside the callback	520	C<send> or C<croak> are called. Calling C<recv> inside the callback
506	or at any later time is guaranteed not to block.	521	or at any later time is guaranteed not to block.
507		522
508	=back	523	=back
		524
		525	=head3 MAINLOOP EMULATION
		526
		527	Sometimes (often for short test scripts, or even standalone programs
		528	who only want to use AnyEvent), you I<do> want your program to block
		529	indefinitely in some event loop.
		530
		531	In that case, you cna use a condition variable like this:
		532
		533	AnyEvent->condvar->recv;
		534
		535	This has the effect of entering the event loop and looping forever.
		536
		537	Note that usually your program has some exit condition, in which case
		538	it is better to use the "traditional" approach of storing a condition
		539	variable, waiting for it, and sending it when the program should exit
		540	cleanly.
		541
509		542
510	=head1 GLOBAL VARIABLES AND FUNCTIONS	543	=head1 GLOBAL VARIABLES AND FUNCTIONS
511		544
512	=over 4	545	=over 4
513		546
…		…
519	C<AnyEvent::Impl:xxx> modules, but can be any other class in the case	552	C<AnyEvent::Impl:xxx> modules, but can be any other class in the case
520	AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode>).	553	AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode>).
521		554
522	The known classes so far are:	555	The known classes so far are:
523		556
524	AnyEvent::Impl::CoroEV based on Coro::EV, best choice.
525	AnyEvent::Impl::CoroEvent based on Coro::Event, second best choice.
526	AnyEvent::Impl::EV based on EV (an interface to libev, best choice).	557	AnyEvent::Impl::EV based on EV (an interface to libev, best choice).
527	AnyEvent::Impl::Event based on Event, second best choice.	558	AnyEvent::Impl::Event based on Event, second best choice.
528	AnyEvent::Impl::Perl pure-perl implementation, fast and portable.	559	AnyEvent::Impl::Perl pure-perl implementation, fast and portable.
529	AnyEvent::Impl::Glib based on Glib, third-best choice.	560	AnyEvent::Impl::Glib based on Glib, third-best choice.
530	AnyEvent::Impl::Tk based on Tk, very bad choice.	561	AnyEvent::Impl::Tk based on Tk, very bad choice.
…		…
547	Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model	578	Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model
548	if necessary. You should only call this function right before you would	579	if necessary. You should only call this function right before you would
549	have created an AnyEvent watcher anyway, that is, as late as possible at	580	have created an AnyEvent watcher anyway, that is, as late as possible at
550	runtime.	581	runtime.
551		582
		583	=item $guard = AnyEvent::post_detect { BLOCK }
		584
		585	Arranges for the code block to be executed as soon as the event model is
		586	autodetected (or immediately if this has already happened).
		587
		588	If called in scalar or list context, then it creates and returns an object
		589	that automatically removes the callback again when it is destroyed. See
		590	L<Coro::BDB> for a case where this is useful.
		591
		592	=item @AnyEvent::post_detect
		593
		594	If there are any code references in this array (you can C<push> to it
		595	before or after loading AnyEvent), then they will called directly after
		596	the event loop has been chosen.
		597
		598	You should check C<$AnyEvent::MODEL> before adding to this array, though:
		599	if it contains a true value then the event loop has already been detected,
		600	and the array will be ignored.
		601
		602	Best use C<AnyEvent::post_detect { BLOCK }> instead.
		603
552	=back	604	=back
553		605
554	=head1 WHAT TO DO IN A MODULE	606	=head1 WHAT TO DO IN A MODULE
555		607
556	As a module author, you should C<use AnyEvent> and call AnyEvent methods	608	As a module author, you should C<use AnyEvent> and call AnyEvent methods
…		…
559	Be careful when you create watchers in the module body - AnyEvent will	611	Be careful when you create watchers in the module body - AnyEvent will
560	decide which event module to use as soon as the first method is called, so	612	decide which event module to use as soon as the first method is called, so
561	by calling AnyEvent in your module body you force the user of your module	613	by calling AnyEvent in your module body you force the user of your module
562	to load the event module first.	614	to load the event module first.
563		615
564	Never call C<< ->wait >> on a condition variable unless you I<know> that	616	Never call C<< ->recv >> on a condition variable unless you I<know> that
565	the C<< ->send >> method has been called on it already. This is	617	the C<< ->send >> method has been called on it already. This is
566	because it will stall the whole program, and the whole point of using	618	because it will stall the whole program, and the whole point of using
567	events is to stay interactive.	619	events is to stay interactive.
568		620
569	It is fine, however, to call C<< ->wait >> when the user of your module	621	It is fine, however, to call C<< ->recv >> when the user of your module
570	requests it (i.e. if you create a http request object ad have a method	622	requests it (i.e. if you create a http request object ad have a method
571	called C<results> that returns the results, it should call C<< ->wait >>	623	called C<results> that returns the results, it should call C<< ->recv >>
572	freely, as the user of your module knows what she is doing. always).	624	freely, as the user of your module knows what she is doing. always).
573		625
574	=head1 WHAT TO DO IN THE MAIN PROGRAM	626	=head1 WHAT TO DO IN THE MAIN PROGRAM
575		627
576	There will always be a single main program - the only place that should	628	There will always be a single main program - the only place that should
…		…
610		662
611	Provide read and write buffers and manages watchers for reads and writes.	663	Provide read and write buffers and manages watchers for reads and writes.
612		664
613	=item L<AnyEvent::Socket>	665	=item L<AnyEvent::Socket>
614		666
615	Provides a means to do non-blocking connects, accepts etc.	667	Provides various utility functions for (internet protocol) sockets,
		668	addresses and name resolution. Also functions to create non-blocking tcp
		669	connections or tcp servers, with IPv6 and SRV record support and more.
616		670
617	=item L<AnyEvent::HTTPD>	671	=item L<AnyEvent::HTTPD>
618		672
619	Provides a simple web application server framework.	673	Provides a simple web application server framework.
620		674
621	=item L<AnyEvent::DNS>	675	=item L<AnyEvent::DNS>
622		676
623	Provides asynchronous DNS resolver capabilities, beyond what	677	Provides rich asynchronous DNS resolver capabilities.
624	L<AnyEvent::Util> offers.
625		678
626	=item L<AnyEvent::FastPing>	679	=item L<AnyEvent::FastPing>
627		680
628	The fastest ping in the west.	681	The fastest ping in the west.
629		682
…		…
644		697
645	High level API for event-based execution flow control.	698	High level API for event-based execution flow control.
646		699
647	=item L<Coro>	700	=item L<Coro>
648		701
649	Has special support for AnyEvent.	702	Has special support for AnyEvent via L<Coro::AnyEvent>.
		703
		704	=item L<AnyEvent::AIO>, L<IO::AIO>
		705
		706	Truly asynchronous I/O, should be in the toolbox of every event
		707	programmer. AnyEvent::AIO transparently fuses IO::AIO and AnyEvent
		708	together.
		709
		710	=item L<AnyEvent::BDB>, L<BDB>
		711
		712	Truly asynchronous Berkeley DB access. AnyEvent::AIO transparently fuses
		713	IO::AIO and AnyEvent together.
650		714
651	=item L<IO::Lambda>	715	=item L<IO::Lambda>
652		716
653	The lambda approach to I/O - don't ask, look there. Can use AnyEvent.	717	The lambda approach to I/O - don't ask, look there. Can use AnyEvent.
654
655	=item L<IO::AIO>
656
657	Truly asynchronous I/O, should be in the toolbox of every event
658	programmer. Can be trivially made to use AnyEvent.
659
660	=item L<BDB>
661
662	Truly asynchronous Berkeley DB access. Can be trivially made to use
663	AnyEvent.
664		718
665	=back	719	=back
666		720
667	=cut	721	=cut
668		722
…		…
671	no warnings;	725	no warnings;
672	use strict;	726	use strict;
673		727
674	use Carp;	728	use Carp;
675		729
676	our $VERSION = '3.3';	730	our $VERSION = '4.03';
677	our $MODEL;	731	our $MODEL;
678		732
679	our $AUTOLOAD;	733	our $AUTOLOAD;
680	our @ISA;	734	our @ISA;
681		735
682	our $verbose = $ENV{PERL_ANYEVENT_VERBOSE}*1;	736	our $verbose = $ENV{PERL_ANYEVENT_VERBOSE}*1;
683		737
684	our @REGISTRY;	738	our @REGISTRY;
685		739
		740	our %PROTOCOL; # (ipv4\|ipv6) => (1\|2)
		741
		742	{
		743	my $idx;
		744	$PROTOCOL{$_} = ++$idx
		745	for split /\s,\s/, $ENV{PERL_ANYEVENT_PROTOCOLS} \|\| "ipv4,ipv6";
		746	}
		747
686	my @models = (	748	my @models = (
687	[Coro::EV:: => AnyEvent::Impl::CoroEV::],
688	[Coro::Event:: => AnyEvent::Impl::CoroEvent::],
689	[EV:: => AnyEvent::Impl::EV::],	749	[EV:: => AnyEvent::Impl::EV::],
690	[Event:: => AnyEvent::Impl::Event::],	750	[Event:: => AnyEvent::Impl::Event::],
691	[Tk:: => AnyEvent::Impl::Tk::],	751	[Tk:: => AnyEvent::Impl::Tk::],
692	[Wx:: => AnyEvent::Impl::POE::],	752	[Wx:: => AnyEvent::Impl::POE::],
693	[Prima:: => AnyEvent::Impl::POE::],	753	[Prima:: => AnyEvent::Impl::POE::],
…		…
699	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza	759	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza
700	);	760	);
701		761
702	our %method = map +($_ => 1), qw(io timer signal child condvar one_event DESTROY);	762	our %method = map +($_ => 1), qw(io timer signal child condvar one_event DESTROY);
703		763
		764	our @post_detect;
		765
		766	sub post_detect(&) {
		767	my ($cb) = @_;
		768
		769	if ($MODEL) {
		770	$cb->();
		771
		772	1
		773	} else {
		774	push @post_detect, $cb;
		775
		776	defined wantarray
		777	? bless \$cb, "AnyEvent::Util::PostDetect"
		778	: ()
		779	}
		780	}
		781
		782	sub AnyEvent::Util::PostDetect::DESTROY {
		783	@post_detect = grep $_ != ${$_[0]}, @post_detect;
		784	}
		785
704	sub detect() {	786	sub detect() {
705	unless ($MODEL) {	787	unless ($MODEL) {
706	no strict 'refs';	788	no strict 'refs';
707		789
708	if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) {	790	if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) {
…		…
741	last;	823	last;
742	}	824	}
743	}	825	}
744		826
745	$MODEL	827	$MODEL
746	or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV (or Coro+EV), Event (or Coro+Event) or Glib.";	828	or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV, Event or Glib.";
747	}	829	}
748	}	830	}
749		831
750	unshift @ISA, $MODEL;	832	unshift @ISA, $MODEL;
751	push @{"$MODEL\::ISA"}, "AnyEvent::Base";	833	push @{"$MODEL\::ISA"}, "AnyEvent::Base";
		834
		835	(shift @post_detect)->() while @post_detect;
752	}	836	}
753		837
754	$MODEL	838	$MODEL
755	}	839	}
756		840
…		…
766	$class->$func (@_);	850	$class->$func (@_);
767	}	851	}
768		852
769	package AnyEvent::Base;	853	package AnyEvent::Base;
770		854
771	# default implementation for ->condvar, ->wait, ->broadcast	855	# default implementation for ->condvar
772		856
773	sub condvar {	857	sub condvar {
774	bless \my $flag, "AnyEvent::Base::CondVar"	858	bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, AnyEvent::CondVar::
775	}
776
777	sub AnyEvent::Base::CondVar::broadcast {
778	${$_[0]}++;
779	}
780
781	sub AnyEvent::Base::CondVar::wait {
782	AnyEvent->one_event while !${$_[0]};
783	}	859	}
784		860
785	# default implementation for ->signal	861	# default implementation for ->signal
786		862
787	our %SIG_CB;	863	our %SIG_CB;
…		…
861	delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };	937	delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };
862		938
863	undef $CHLD_W unless keys %PID_CB;	939	undef $CHLD_W unless keys %PID_CB;
864	}	940	}
865		941
		942	package AnyEvent::CondVar;
		943
		944	our @ISA = AnyEvent::CondVar::Base::;
		945
		946	package AnyEvent::CondVar::Base;
		947
		948	use overload
		949	'&{}' => sub { my $self = shift; sub { $self->send (@_) } },
		950	fallback => 1;
		951
		952	sub _send {
		953	# nop
		954	}
		955
		956	sub send {
		957	my $cv = shift;
		958	$cv->{_ae_sent} = [@_];
		959	(delete $cv->{_ae_cb})->($cv) if $cv->{_ae_cb};
		960	$cv->_send;
		961	}
		962
		963	sub croak {
		964	$_[0]{_ae_croak} = $_[1];
		965	$_[0]->send;
		966	}
		967
		968	sub ready {
		969	$_[0]{_ae_sent}
		970	}
		971
		972	sub _wait {
		973	AnyEvent->one_event while !$_[0]{_ae_sent};
		974	}
		975
		976	sub recv {
		977	$_[0]->_wait;
		978
		979	Carp::croak $_[0]{_ae_croak} if $_[0]{_ae_croak};
		980	wantarray ? @{ $_[0]{_ae_sent} } : $_[0]{_ae_sent}[0]
		981	}
		982
		983	sub cb {
		984	$_[0]{_ae_cb} = $_[1] if @_ > 1;
		985	$_[0]{_ae_cb}
		986	}
		987
		988	sub begin {
		989	++$_[0]{_ae_counter};
		990	$_[0]{_ae_end_cb} = $_[1] if @_ > 1;
		991	}
		992
		993	sub end {
		994	return if --$_[0]{_ae_counter};
		995	&{ $_[0]{_ae_end_cb} \|\| sub { $_[0]->send } };
		996	}
		997
		998	# undocumented/compatibility with pre-3.4
		999	*broadcast = \&send;
		1000	*wait = \&_wait;
		1001
866	=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE	1002	=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE
867		1003
868	This is an advanced topic that you do not normally need to use AnyEvent in	1004	This is an advanced topic that you do not normally need to use AnyEvent in
869	a module. This section is only of use to event loop authors who want to	1005	a module. This section is only of use to event loop authors who want to
870	provide AnyEvent compatibility.	1006	provide AnyEvent compatibility.
…		…
926	model it chooses.	1062	model it chooses.
927		1063
928	=item C<PERL_ANYEVENT_MODEL>	1064	=item C<PERL_ANYEVENT_MODEL>
929		1065
930	This can be used to specify the event model to be used by AnyEvent, before	1066	This can be used to specify the event model to be used by AnyEvent, before
931	autodetection and -probing kicks in. It must be a string consisting	1067	auto detection and -probing kicks in. It must be a string consisting
932	entirely of ASCII letters. The string C<AnyEvent::Impl::> gets prepended	1068	entirely of ASCII letters. The string C<AnyEvent::Impl::> gets prepended
933	and the resulting module name is loaded and if the load was successful,	1069	and the resulting module name is loaded and if the load was successful,
934	used as event model. If it fails to load AnyEvent will proceed with	1070	used as event model. If it fails to load AnyEvent will proceed with
935	autodetection and -probing.	1071	auto detection and -probing.
936		1072
937	This functionality might change in future versions.	1073	This functionality might change in future versions.
938		1074
939	For example, to force the pure perl model (L<AnyEvent::Impl::Perl>) you	1075	For example, to force the pure perl model (L<AnyEvent::Impl::Perl>) you
940	could start your program like this:	1076	could start your program like this:
941		1077
942	PERL_ANYEVENT_MODEL=Perl perl ...	1078	PERL_ANYEVENT_MODEL=Perl perl ...
		1079
		1080	=item C<PERL_ANYEVENT_PROTOCOLS>
		1081
		1082	Used by both L<AnyEvent::DNS> and L<AnyEvent::Socket> to determine preferences
		1083	for IPv4 or IPv6. The default is unspecified (and might change, or be the result
		1084	of auto probing).
		1085
		1086	Must be set to a comma-separated list of protocols or address families,
		1087	current supported: C<ipv4> and C<ipv6>. Only protocols mentioned will be
		1088	used, and preference will be given to protocols mentioned earlier in the
		1089	list.
		1090
		1091	This variable can effectively be used for denial-of-service attacks
		1092	against local programs (e.g. when setuid), although the impact is likely
		1093	small, as the program has to handle connection errors already-
		1094
		1095	Examples: C<PERL_ANYEVENT_PROTOCOLS=ipv4,ipv6> - prefer IPv4 over IPv6,
		1096	but support both and try to use both. C<PERL_ANYEVENT_PROTOCOLS=ipv4>
		1097	- only support IPv4, never try to resolve or contact IPv6
		1098	addresses. C<PERL_ANYEVENT_PROTOCOLS=ipv6,ipv4> support either IPv4 or
		1099	IPv6, but prefer IPv6 over IPv4.
		1100
		1101	=item C<PERL_ANYEVENT_EDNS0>
		1102
		1103	Used by L<AnyEvent::DNS> to decide whether to use the EDNS0 extension
		1104	for DNS. This extension is generally useful to reduce DNS traffic, but
		1105	some (broken) firewalls drop such DNS packets, which is why it is off by
		1106	default.
		1107
		1108	Setting this variable to C<1> will cause L<AnyEvent::DNS> to announce
		1109	EDNS0 in its DNS requests.
943		1110
944	=back	1111	=back
945		1112
946	=head1 EXAMPLE PROGRAM	1113	=head1 EXAMPLE PROGRAM
947		1114
…		…
958	poll => 'r',	1125	poll => 'r',
959	cb => sub {	1126	cb => sub {
960	warn "io event <$_[0]>\n"; # will always output <r>	1127	warn "io event <$_[0]>\n"; # will always output <r>
961	chomp (my $input = <STDIN>); # read a line	1128	chomp (my $input = <STDIN>); # read a line
962	warn "read: $input\n"; # output what has been read	1129	warn "read: $input\n"; # output what has been read
963	$cv->broadcast if $input =~ /^q/i; # quit program if /^q/i	1130	$cv->send if $input =~ /^q/i; # quit program if /^q/i
964	},	1131	},
965	);	1132	);
966		1133
967	my $time_watcher; # can only be used once	1134	my $time_watcher; # can only be used once
968		1135
…		…
973	});	1140	});
974	}	1141	}
975		1142
976	new_timer; # create first timer	1143	new_timer; # create first timer
977		1144
978	$cv->wait; # wait until user enters /^q/i	1145	$cv->recv; # wait until user enters /^q/i
979		1146
980	=head1 REAL-WORLD EXAMPLE	1147	=head1 REAL-WORLD EXAMPLE
981		1148
982	Consider the L<Net::FCP> module. It features (among others) the following	1149	Consider the L<Net::FCP> module. It features (among others) the following
983	API calls, which are to freenet what HTTP GET requests are to http:	1150	API calls, which are to freenet what HTTP GET requests are to http:
…		…
1033	syswrite $txn->{fh}, $txn->{request}	1200	syswrite $txn->{fh}, $txn->{request}
1034	or die "connection or write error";	1201	or die "connection or write error";
1035	$txn->{w} = AnyEvent->io (fh => $txn->{fh}, poll => 'r', cb => sub { $txn->fh_ready_r });	1202	$txn->{w} = AnyEvent->io (fh => $txn->{fh}, poll => 'r', cb => sub { $txn->fh_ready_r });
1036		1203
1037	Again, C<fh_ready_r> waits till all data has arrived, and then stores the	1204	Again, C<fh_ready_r> waits till all data has arrived, and then stores the
1038	result and signals any possible waiters that the request ahs finished:	1205	result and signals any possible waiters that the request has finished:
1039		1206
1040	sysread $txn->{fh}, $txn->{buf}, length $txn->{$buf};	1207	sysread $txn->{fh}, $txn->{buf}, length $txn->{$buf};
1041		1208
1042	if (end-of-file or data complete) {	1209	if (end-of-file or data complete) {
1043	$txn->{result} = $txn->{buf};	1210	$txn->{result} = $txn->{buf};
1044	$txn->{finished}->broadcast;	1211	$txn->{finished}->send;
1045	$txb->{cb}->($txn) of $txn->{cb}; # also call callback	1212	$txb->{cb}->($txn) of $txn->{cb}; # also call callback
1046	}	1213	}
1047		1214
1048	The C<result> method, finally, just waits for the finished signal (if the	1215	The C<result> method, finally, just waits for the finished signal (if the
1049	request was already finished, it doesn't wait, of course, and returns the	1216	request was already finished, it doesn't wait, of course, and returns the
1050	data:	1217	data:
1051		1218
1052	$txn->{finished}->wait;	1219	$txn->{finished}->recv;
1053	return $txn->{result};	1220	return $txn->{result};
1054		1221
1055	The actual code goes further and collects all errors (C<die>s, exceptions)	1222	The actual code goes further and collects all errors (C<die>s, exceptions)
1056	that occured during request processing. The C<result> method detects	1223	that occurred during request processing. The C<result> method detects
1057	whether an exception as thrown (it is stored inside the $txn object)	1224	whether an exception as thrown (it is stored inside the $txn object)
1058	and just throws the exception, which means connection errors and other	1225	and just throws the exception, which means connection errors and other
1059	problems get reported tot he code that tries to use the result, not in a	1226	problems get reported tot he code that tries to use the result, not in a
1060	random callback.	1227	random callback.
1061		1228
…		…
1092		1259
1093	my $quit = AnyEvent->condvar;	1260	my $quit = AnyEvent->condvar;
1094		1261
1095	$fcp->txn_client_get ($url)->cb (sub {	1262	$fcp->txn_client_get ($url)->cb (sub {
1096	...	1263	...
1097	$quit->broadcast;	1264	$quit->send;
1098	});	1265	});
1099		1266
1100	$quit->wait;	1267	$quit->recv;
1101		1268
1102		1269
1103	=head1 BENCHMARKS	1270	=head1 BENCHMARKS
1104		1271
1105	To give you an idea of the performance and overheads that AnyEvent adds	1272	To give you an idea of the performance and overheads that AnyEvent adds
…		…
1107	of various event loops I prepared some benchmarks.	1274	of various event loops I prepared some benchmarks.
1108		1275
1109	=head2 BENCHMARKING ANYEVENT OVERHEAD	1276	=head2 BENCHMARKING ANYEVENT OVERHEAD
1110		1277
1111	Here is a benchmark of various supported event models used natively and	1278	Here is a benchmark of various supported event models used natively and
1112	through anyevent. The benchmark creates a lot of timers (with a zero	1279	through AnyEvent. The benchmark creates a lot of timers (with a zero
1113	timeout) and I/O watchers (watching STDOUT, a pty, to become writable,	1280	timeout) and I/O watchers (watching STDOUT, a pty, to become writable,
1114	which it is), lets them fire exactly once and destroys them again.	1281	which it is), lets them fire exactly once and destroys them again.
1115		1282
1116	Source code for this benchmark is found as F<eg/bench> in the AnyEvent	1283	Source code for this benchmark is found as F<eg/bench> in the AnyEvent
1117	distribution.	1284	distribution.
…		…
1134	all watchers, to avoid adding memory overhead. That means closure creation	1301	all watchers, to avoid adding memory overhead. That means closure creation
1135	and memory usage is not included in the figures.	1302	and memory usage is not included in the figures.
1136		1303
1137	I<invoke> is the time, in microseconds, used to invoke a simple	1304	I<invoke> is the time, in microseconds, used to invoke a simple
1138	callback. The callback simply counts down a Perl variable and after it was	1305	callback. The callback simply counts down a Perl variable and after it was
1139	invoked "watcher" times, it would C<< ->broadcast >> a condvar once to	1306	invoked "watcher" times, it would C<< ->send >> a condvar once to
1140	signal the end of this phase.	1307	signal the end of this phase.
1141		1308
1142	I<destroy> is the time, in microseconds, that it takes to destroy a single	1309	I<destroy> is the time, in microseconds, that it takes to destroy a single
1143	watcher.	1310	watcher.
1144		1311
…		…
1240		1407
1241	=back	1408	=back
1242		1409
1243	=head2 BENCHMARKING THE LARGE SERVER CASE	1410	=head2 BENCHMARKING THE LARGE SERVER CASE
1244		1411
1245	This benchmark atcually benchmarks the event loop itself. It works by	1412	This benchmark actually benchmarks the event loop itself. It works by
1246	creating a number of "servers": each server consists of a socketpair, a	1413	creating a number of "servers": each server consists of a socket pair, a
1247	timeout watcher that gets reset on activity (but never fires), and an I/O	1414	timeout watcher that gets reset on activity (but never fires), and an I/O
1248	watcher waiting for input on one side of the socket. Each time the socket	1415	watcher waiting for input on one side of the socket. Each time the socket
1249	watcher reads a byte it will write that byte to a random other "server".	1416	watcher reads a byte it will write that byte to a random other "server".
1250		1417
1251	The effect is that there will be a lot of I/O watchers, only part of which	1418	The effect is that there will be a lot of I/O watchers, only part of which
1252	are active at any one point (so there is a constant number of active	1419	are active at any one point (so there is a constant number of active
1253	fds for each loop iterstaion, but which fds these are is random). The	1420	fds for each loop iteration, but which fds these are is random). The
1254	timeout is reset each time something is read because that reflects how	1421	timeout is reset each time something is read because that reflects how
1255	most timeouts work (and puts extra pressure on the event loops).	1422	most timeouts work (and puts extra pressure on the event loops).
1256		1423
1257	In this benchmark, we use 10000 socketpairs (20000 sockets), of which 100	1424	In this benchmark, we use 10000 socket pairs (20000 sockets), of which 100
1258	(1%) are active. This mirrors the activity of large servers with many	1425	(1%) are active. This mirrors the activity of large servers with many
1259	connections, most of which are idle at any one point in time.	1426	connections, most of which are idle at any one point in time.
1260		1427
1261	Source code for this benchmark is found as F<eg/bench2> in the AnyEvent	1428	Source code for this benchmark is found as F<eg/bench2> in the AnyEvent
1262	distribution.	1429	distribution.
…		…
1264	=head3 Explanation of the columns	1431	=head3 Explanation of the columns
1265		1432
1266	I<sockets> is the number of sockets, and twice the number of "servers" (as	1433	I<sockets> is the number of sockets, and twice the number of "servers" (as
1267	each server has a read and write socket end).	1434	each server has a read and write socket end).
1268		1435
1269	I<create> is the time it takes to create a socketpair (which is	1436	I<create> is the time it takes to create a socket pair (which is
1270	nontrivial) and two watchers: an I/O watcher and a timeout watcher.	1437	nontrivial) and two watchers: an I/O watcher and a timeout watcher.
1271		1438
1272	I<request>, the most important value, is the time it takes to handle a	1439	I<request>, the most important value, is the time it takes to handle a
1273	single "request", that is, reading the token from the pipe and forwarding	1440	single "request", that is, reading the token from the pipe and forwarding
1274	it to another server. This includes deleting the old timeout and creating	1441	it to another server. This includes deleting the old timeout and creating
…		…
1347	speed most when you have lots of watchers, not when you only have a few of	1514	speed most when you have lots of watchers, not when you only have a few of
1348	them).	1515	them).
1349		1516
1350	EV is again fastest.	1517	EV is again fastest.
1351		1518
1352	Perl again comes second. It is noticably faster than the C-based event	1519	Perl again comes second. It is noticeably faster than the C-based event
1353	loops Event and Glib, although the difference is too small to really	1520	loops Event and Glib, although the difference is too small to really
1354	matter.	1521	matter.
1355		1522
1356	POE also performs much better in this case, but is is still far behind the	1523	POE also performs much better in this case, but is is still far behind the
1357	others.	1524	others.
…		…
1397	probably even less useful to an attacker than PERL_ANYEVENT_MODEL).	1564	probably even less useful to an attacker than PERL_ANYEVENT_MODEL).
1398		1565
1399		1566
1400	=head1 SEE ALSO	1567	=head1 SEE ALSO
1401		1568
1402	Event modules: L<Coro::EV>, L<EV>, L<EV::Glib>, L<Glib::EV>,	1569	Utility functions: L<AnyEvent::Util>.
1403	L<Coro::Event>, L<Event>, L<Glib::Event>, L<Glib>, L<Coro>, L<Tk>,	1570
		1571	Event modules: L<EV>, L<EV::Glib>, L<Glib::EV>, L<Event>, L<Glib::Event>,
1404	L<Event::Lib>, L<Qt>, L<POE>.	1572	L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>.
1405		1573
1406	Implementations: L<AnyEvent::Impl::CoroEV>, L<AnyEvent::Impl::EV>,	1574	Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>,
1407	L<AnyEvent::Impl::CoroEvent>, L<AnyEvent::Impl::Event>, L<AnyEvent::Impl::Glib>,	1575	L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>,
1408	L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>, L<AnyEvent::Impl::EventLib>,	1576	L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>,
1409	L<AnyEvent::Impl::Qt>, L<AnyEvent::Impl::POE>.	1577	L<AnyEvent::Impl::POE>.
1410		1578
		1579	Non-blocking file handles, sockets, TCP clients and
		1580	servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>.
		1581
		1582	Asynchronous DNS: L<AnyEvent::DNS>.
		1583
		1584	Coroutine support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>, L<Coro::Event>,
		1585
1411	Nontrivial usage examples: L<Net::FCP>, L<Net::XMPP2>.	1586	Nontrivial usage examples: L<Net::FCP>, L<Net::XMPP2>, L<AnyEvent::DNS>.
1412		1587
1413		1588
1414	=head1 AUTHOR	1589	=head1 AUTHOR
1415		1590
1416	Marc Lehmann <schmorp@schmorp.de>	1591	Marc Lehmann <schmorp@schmorp.de>

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Comparing AnyEvent/lib/AnyEvent.pm (file contents): Revision 1.107 by root, Tue May 6 12:15:50 2008 UTC vs. Revision 1.133 by root, Sun May 25 03:44:03 2008 UTC

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Comparing AnyEvent/lib/AnyEvent.pm (file contents):
Revision 1.107 by root, Tue May 6 12:15:50 2008 UTC vs.
Revision 1.133 by root, Sun May 25 03:44:03 2008 UTC