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

Comparing AnyEvent/lib/AnyEvent.pm (file contents):
Revision 1.100 by elmex, Sun Apr 27 19:15:43 2008 UTC vs.
Revision 1.109 by root, Sat May 10 00:45:18 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->wait; # enters "main loop" till $condvar gets ->broadcast	20	$w->wait; # enters "main loop" till $condvar gets ->send
21	$w->broadcast; # wake up current and all future wait's	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?
…		…
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
68	useful) and you want to force your users to use the one and only event	68	useful) and you want to force your users to use the one and only event
69	model, you should I<not> use this module.	69	model, you should I<not> use this module.
70		70
71	#TODO#
72
73	Net::IRC3
74	AnyEvent::HTTPD
75	AnyEvent::DNS
76	IO::AnyEvent
77	Net::FPing
78	Net::XMPP2
79	Coro
80
81	AnyEvent::IRC
82	AnyEvent::HTTPD
83	AnyEvent::DNS
84	AnyEvent::Handle
85	AnyEvent::Socket
86	AnyEvent::FPing
87	AnyEvent::XMPP
88	AnyEvent::SNMP
89	Coro
90
91	=head1 DESCRIPTION	71	=head1 DESCRIPTION
92		72
93	L<AnyEvent> provides an identical interface to multiple event loops. This	73	L<AnyEvent> provides an identical interface to multiple event loops. This
94	allows module authors to utilise an event loop without forcing module	74	allows module authors to utilise an event loop without forcing module
95	users to use the same event loop (as only a single event loop can coexist	75	users to use the same event loop (as only a single event loop can coexist
…		…
98	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>
99	module.	79	module.
100		80
101	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
102	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
103	following modules is already loaded: L<Coro::EV>, L<Coro::Event>, L<EV>,	83	following modules is already loaded: L<EV>,
104	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>,
105	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
106	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
107	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
108	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
…		…
308	my $w = AnyEvent->child (	288	my $w = AnyEvent->child (
309	pid => $pid,	289	pid => $pid,
310	cb => sub {	290	cb => sub {
311	my ($pid, $status) = @_;	291	my ($pid, $status) = @_;
312	warn "pid $pid exited with status $status";	292	warn "pid $pid exited with status $status";
313	$done->broadcast;	293	$done->send;
314	},	294	},
315	);	295	);
316		296
317	# do something else, then wait for process exit	297	# do something else, then wait for process exit
318	$done->wait;	298	$done->wait;
319		299
320	=head2 CONDITION VARIABLES	300	=head2 CONDITION VARIABLES
321		301
		302	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
		304	will actively watch for new events and call your callbacks.
		305
		306	AnyEvent is different, it expects somebody else to run the event loop and
		307	will only block when necessary (usually when told by the user).
		308
		309	The instrument to do that is called a "condition variable", so called
		310	because they represent a condition that must become true.
		311
322	Condition variables can be created by calling the C<< AnyEvent->condvar >>	312	Condition variables can be created by calling the C<< AnyEvent->condvar
323	method without any arguments.	313	>> method, usually without arguments. The only argument pair allowed is
		314	C<cb>, which specifies a callback to be called when the condition variable
		315	becomes true.
324		316
325	A condition variable waits for a condition - precisely that the C<<	317	After creation, the conditon variable is "false" until it becomes "true"
326	->broadcast >> method has been called.	318	by calling the C<send> method.
327		319
328	They are very useful to signal that a condition has been fulfilled, for	320	Condition variables are similar to callbacks, except that you can
		321	optionally wait for them. They can also be called merge points - points
		322	in time where multiple outstandign events have been processed. And yet
		323	another way to call them is transations - each condition variable can be
		324	used to represent a transaction, which finishes at some point and delivers
		325	a result.
		326
		327	Condition variables are very useful to signal that something has finished,
329	example, if you write a module that does asynchronous http requests,	328	for example, if you write a module that does asynchronous http requests,
330	then a condition variable would be the ideal candidate to signal the	329	then a condition variable would be the ideal candidate to signal the
331	availability of results.	330	availability of results. The user can either act when the callback is
		331	called or can synchronously C<< ->wait >> for the results.
332		332
333	You can also use condition variables to block your main program until	333	You can also use them to simulate traditional event loops - for example,
334	an event occurs - for example, you could C<< ->wait >> in your main	334	you can block your main program until an event occurs - for example, you
335	program until the user clicks the Quit button in your app, which would C<<	335	could C<< ->wait >> in your main program until the user clicks the Quit
336	->broadcast >> the "quit" event.	336	button of your app, which would C<< ->send >> the "quit" event.
337		337
338	Note that condition variables recurse into the event loop - if you have	338	Note that condition variables recurse into the event loop - if you have
339	two pirces of code that call C<< ->wait >> in a round-robbin fashion, you	339	two pieces of code that call C<< ->wait >> in a round-robbin fashion, you
340	lose. Therefore, condition variables are good to export to your caller, but	340	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,	341	you should avoid making a blocking wait yourself, at least in callbacks,
342	as this asks for trouble.	342	as this asks for trouble.
343		343
344	This object has two methods:	344	Condition variables are represented by hash refs in perl, and the keys
		345	used by AnyEvent itself are all named C<_ae_XXX> to make subclassing
		346	easy (it is often useful to build your own transaction class on top of
		347	AnyEvent). To subclass, use C<AnyEvent::CondVar> as base class and call
		348	it's C<new> method in your own C<new> method.
		349
		350	There are two "sides" to a condition variable - the "producer side" which
		351	eventually calls C<< -> send >>, and the "consumer side", which waits
		352	for the send to occur.
		353
		354	Example:
		355
		356	# wait till the result is ready
		357	my $result_ready = AnyEvent->condvar;
		358
		359	# do something such as adding a timer
		360	# or socket watcher the calls $result_ready->send
		361	# when the "result" is ready.
		362	# in this case, we simply use a timer:
		363	my $w = AnyEvent->timer (
		364	after => 1,
		365	cb => sub { $result_ready->send },
		366	);
		367
		368	# this "blocks" (while handling events) till the callback
		369	# calls send
		370	$result_ready->wait;
		371
		372	=head3 METHODS FOR PRODUCERS
		373
		374	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
		376	the producer side which creates the condvar in most cases, but it isn't
		377	uncommon for the consumer to create it as well.
345		378
346	=over 4	379	=over 4
347		380
		381	=item $cv->send (...)
		382
		383	Flag the condition as ready - a running C<< ->wait >> and all further
		384	calls to C<wait> will (eventually) return after this method has been
		385	called. If nobody is waiting the send will be remembered.
		386
		387	If a callback has been set on the condition variable, it is called
		388	immediately from within send.
		389
		390	Any arguments passed to the C<send> call will be returned by all
		391	future C<< ->wait >> calls.
		392
		393	=item $cv->croak ($error)
		394
		395	Similar to send, but causes all call's wait C<< ->wait >> to invoke
		396	C<Carp::croak> with the given error message/object/scalar.
		397
		398	This can be used to signal any errors to the condition variable
		399	user/consumer.
		400
		401	=item $cv->begin ([group callback])
		402
		403	=item $cv->end
		404
		405	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
		407	to use a condition variable for the whole process.
		408
		409	Every call to C<< ->begin >> will increment a counter, and every call to
		410	C<< ->end >> will decrement it. If the counter reaches C<0> in C<< ->end
		411	>>, the (last) callback passed to C<begin> will be executed. That callback
		412	is I<supposed> to call C<< ->send >>, but that is not required. If no
		413	callback was set, C<send> will be called without any arguments.
		414
		415	Let's clarify this with the ping example:
		416
		417	my $cv = AnyEvent->condvar;
		418
		419	my %result;
		420	$cv->begin (sub { $cv->send (\%result) });
		421
		422	for my $host (@list_of_hosts) {
		423	$cv->begin;
		424	ping_host_then_call_callback $host, sub {
		425	$result{$host} = ...;
		426	$cv->end;
		427	};
		428	}
		429
		430	$cv->end;
		431
		432	This code fragment supposedly pings a number of hosts and calls
		433	C<send> after results for all then have have been gathered - in any
		434	order. To achieve this, the code issues a call to C<begin> when it starts
		435	each ping request and calls C<end> when it has received some result for
		436	it. Since C<begin> and C<end> only maintain a counter, the order in which
		437	results arrive is not relevant.
		438
		439	There is an additional bracketing call to C<begin> and C<end> outside the
		440	loop, which serves two important purposes: first, it sets the callback
		441	to be called once the counter reaches C<0>, and second, it ensures that
		442	C<send> is called even when C<no> hosts are being pinged (the loop
		443	doesn't execute once).
		444
		445	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>
		447	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>.
		449
		450	=back
		451
		452	=head3 METHODS FOR CONSUMERS
		453
		454	These methods should only be used by the consuming side, i.e. the
		455	code awaits the condition.
		456
		457	=over 4
		458
348	=item $cv->wait	459	=item $cv->wait
349		460
350	Wait (blocking if necessary) until the C<< ->broadcast >> method has been	461	Wait (blocking if necessary) until the C<< ->send >> or C<< ->croak
351	called on c<$cv>, while servicing other watchers normally.	462	>> methods have been called on c<$cv>, while servicing other watchers
		463	normally.
352		464
353	You can only wait once on a condition - additional calls will return	465	You can only wait once on a condition - additional calls are valid but
354	immediately.	466	will return immediately.
		467
		468	If an error condition has been set by calling C<< ->croak >>, then this
		469	function will call C<croak>.
		470
		471	In list context, all parameters passed to C<send> will be returned,
		472	in scalar context only the first one will be returned.
355		473
356	Not all event models support a blocking wait - some die in that case	474	Not all event models support a blocking wait - some die in that case
357	(programs might want to do that to stay interactive), so I<if you are	475	(programs might want to do that to stay interactive), so I<if you are
358	using this from a module, never require a blocking wait>, but let the	476	using this from a module, never require a blocking wait>, but let the
359	caller decide whether the call will block or not (for example, by coupling	477	caller decide whether the call will block or not (for example, by coupling
…		…
362	while still suppporting blocking waits if the caller so desires).	480	while still suppporting blocking waits if the caller so desires).
363		481
364	Another reason I<never> to C<< ->wait >> in a module is that you cannot	482	Another reason I<never> to C<< ->wait >> in a module is that you cannot
365	sensibly have two C<< ->wait >>'s in parallel, as that would require	483	sensibly have two C<< ->wait >>'s in parallel, as that would require
366	multiple interpreters or coroutines/threads, none of which C<AnyEvent>	484	multiple interpreters or coroutines/threads, none of which C<AnyEvent>
367	can supply (the coroutine-aware backends L<AnyEvent::Impl::CoroEV> and	485	can supply.
368	L<AnyEvent::Impl::CoroEvent> explicitly support concurrent C<< ->wait >>'s
369	from different coroutines, however).
370		486
371	=item $cv->broadcast	487	The L<Coro> module, however, I<can> and I<does> supply coroutines and, in
		488	fact, L<Coro::AnyEvent> replaces AnyEvent's condvars by coroutine-safe
		489	versions and also integrates coroutines into AnyEvent, making blocking
		490	C<< ->wait >> calls perfectly safe as long as they are done from another
		491	coroutine (one that doesn't run the event loop).
372		492
373	Flag the condition as ready - a running C<< ->wait >> and all further	493	You can ensure that C<< -wait >> never blocks by setting a callback and
374	calls to C<wait> will (eventually) return after this method has been	494	only calling C<< ->wait >> from within that callback (or at a later
375	called. If nobody is waiting the broadcast will be remembered..	495	time). This will work even when the event loop does not support blocking
		496	waits otherwise.
		497
		498	=item $bool = $cv->ready
		499
		500	Returns true when the condition is "true", i.e. whether C<send> or
		501	C<croak> have been called.
		502
		503	=item $cb = $cv->cb ([new callback])
		504
		505	This is a mutator function that returns the callback set and optionally
		506	replaces it before doing so.
		507
		508	The callback will be called when the condition becomes "true", i.e. when
		509	C<send> or C<croak> are called. Calling C<wait> inside the callback
		510	or at any later time is guaranteed not to block.
376		511
377	=back	512	=back
378
379	Example:
380
381	# wait till the result is ready
382	my $result_ready = AnyEvent->condvar;
383
384	# do something such as adding a timer
385	# or socket watcher the calls $result_ready->broadcast
386	# when the "result" is ready.
387	# in this case, we simply use a timer:
388	my $w = AnyEvent->timer (
389	after => 1,
390	cb => sub { $result_ready->broadcast },
391	);
392
393	# this "blocks" (while handling events) till the watcher
394	# calls broadcast
395	$result_ready->wait;
396		513
397	=head1 GLOBAL VARIABLES AND FUNCTIONS	514	=head1 GLOBAL VARIABLES AND FUNCTIONS
398		515
399	=over 4	516	=over 4
400		517
…		…
406	C<AnyEvent::Impl:xxx> modules, but can be any other class in the case	523	C<AnyEvent::Impl:xxx> modules, but can be any other class in the case
407	AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode>).	524	AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode>).
408		525
409	The known classes so far are:	526	The known classes so far are:
410		527
411	AnyEvent::Impl::CoroEV based on Coro::EV, best choice.
412	AnyEvent::Impl::CoroEvent based on Coro::Event, second best choice.
413	AnyEvent::Impl::EV based on EV (an interface to libev, best choice).	528	AnyEvent::Impl::EV based on EV (an interface to libev, best choice).
414	AnyEvent::Impl::Event based on Event, second best choice.	529	AnyEvent::Impl::Event based on Event, second best choice.
		530	AnyEvent::Impl::Perl pure-perl implementation, fast and portable.
415	AnyEvent::Impl::Glib based on Glib, third-best choice.	531	AnyEvent::Impl::Glib based on Glib, third-best choice.
416	AnyEvent::Impl::Perl pure-perl implementation, inefficient but portable.
417	AnyEvent::Impl::Tk based on Tk, very bad choice.	532	AnyEvent::Impl::Tk based on Tk, very bad choice.
418	AnyEvent::Impl::Qt based on Qt, cannot be autoprobed (see its docs).	533	AnyEvent::Impl::Qt based on Qt, cannot be autoprobed (see its docs).
419	AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse.	534	AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse.
420	AnyEvent::Impl::POE based on POE, not generic enough for full support.	535	AnyEvent::Impl::POE based on POE, not generic enough for full support.
421		536
…		…
434	Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model	549	Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model
435	if necessary. You should only call this function right before you would	550	if necessary. You should only call this function right before you would
436	have created an AnyEvent watcher anyway, that is, as late as possible at	551	have created an AnyEvent watcher anyway, that is, as late as possible at
437	runtime.	552	runtime.
438		553
		554	=item AnyEvent::on_detect { BLOCK }
		555
		556	Arranges for the code block to be executed as soon as the event model is
		557	autodetected (or immediately if this has already happened).
		558
		559	=item @AnyEvent::on_detect
		560
		561	If there are any code references in this array (you can C<push> to it
		562	before or after loading AnyEvent), then they will called directly after
		563	the event loop has been chosen.
		564
		565	You should check C<$AnyEvent::MODEL> before adding to this array, though:
		566	if it contains a true value then the event loop has already been detected,
		567	and the array will be ignored.
		568
		569	Best use C<AnyEvent::on_detect { BLOCK }> instead.
		570
439	=back	571	=back
440		572
441	=head1 WHAT TO DO IN A MODULE	573	=head1 WHAT TO DO IN A MODULE
442		574
443	As a module author, you should C<use AnyEvent> and call AnyEvent methods	575	As a module author, you should C<use AnyEvent> and call AnyEvent methods
…		…
447	decide which event module to use as soon as the first method is called, so	579	decide which event module to use as soon as the first method is called, so
448	by calling AnyEvent in your module body you force the user of your module	580	by calling AnyEvent in your module body you force the user of your module
449	to load the event module first.	581	to load the event module first.
450		582
451	Never call C<< ->wait >> on a condition variable unless you I<know> that	583	Never call C<< ->wait >> on a condition variable unless you I<know> that
452	the C<< ->broadcast >> method has been called on it already. This is	584	the C<< ->send >> method has been called on it already. This is
453	because it will stall the whole program, and the whole point of using	585	because it will stall the whole program, and the whole point of using
454	events is to stay interactive.	586	events is to stay interactive.
455		587
456	It is fine, however, to call C<< ->wait >> when the user of your module	588	It is fine, however, to call C<< ->wait >> when the user of your module
457	requests it (i.e. if you create a http request object ad have a method	589	requests it (i.e. if you create a http request object ad have a method
…		…
479	loading the C<AnyEvent::Impl::Perl> module, which gives you similar	611	loading the C<AnyEvent::Impl::Perl> module, which gives you similar
480	behaviour everywhere, but letting AnyEvent chose is generally better.	612	behaviour everywhere, but letting AnyEvent chose is generally better.
481		613
482	=head1 OTHER MODULES	614	=head1 OTHER MODULES
483		615
484	L<AnyEvent> itself comes with useful utility modules:	616	The following is a non-exhaustive list of additional modules that use
485		617	AnyEvent and can therefore be mixed easily with other AnyEvent modules
486	To make it easier to do non-blocking IO the modules L<AnyEvent::Handle>	618	in the same program. Some of the modules come with AnyEvent, some are
487	and L<AnyEvent::Socket> are provided. L<AnyEvent::Handle> provides	619	available via CPAN.
488	read and write buffers and manages watchers for reads and writes.
489	L<AnyEvent::Socket> provides means to do non-blocking connects.
490
491	Aside from those there are these modules that support AnyEvent (and use it
492	for non-blocking IO):
493		620
494	=over 4	621	=over 4
495		622
		623	=item L<AnyEvent::Util>
		624
		625	Contains various utility functions that replace often-used but blocking
		626	functions such as C<inet_aton> by event-/callback-based versions.
		627
		628	=item L<AnyEvent::Handle>
		629
		630	Provide read and write buffers and manages watchers for reads and writes.
		631
		632	=item L<AnyEvent::Socket>
		633
		634	Provides a means to do non-blocking connects, accepts etc.
		635
		636	=item L<AnyEvent::HTTPD>
		637
		638	Provides a simple web application server framework.
		639
		640	=item L<AnyEvent::DNS>
		641
		642	Provides asynchronous DNS resolver capabilities, beyond what
		643	L<AnyEvent::Util> offers.
		644
496	=item L<AnyEvent::FastPing>	645	=item L<AnyEvent::FastPing>
497		646
		647	The fastest ping in the west.
		648
498	=item L<Net::IRC3>	649	=item L<Net::IRC3>
499		650
		651	AnyEvent based IRC client module family.
		652
500	=item L<Net::XMPP2>	653	=item L<Net::XMPP2>
		654
		655	AnyEvent based XMPP (Jabber protocol) module family.
		656
		657	=item L<Net::FCP>
		658
		659	AnyEvent-based implementation of the Freenet Client Protocol, birthplace
		660	of AnyEvent.
		661
		662	=item L<Event::ExecFlow>
		663
		664	High level API for event-based execution flow control.
		665
		666	=item L<Coro>
		667
		668	Has special support for AnyEvent via L<Coro::AnyEvent>.
		669
		670	=item L<IO::Lambda>
		671
		672	The lambda approach to I/O - don't ask, look there. Can use AnyEvent.
		673
		674	=item L<IO::AIO>
		675
		676	Truly asynchronous I/O, should be in the toolbox of every event
		677	programmer. Can be trivially made to use AnyEvent.
		678
		679	=item L<BDB>
		680
		681	Truly asynchronous Berkeley DB access. Can be trivially made to use
		682	AnyEvent.
501		683
502	=back	684	=back
503		685
504	=cut	686	=cut
505		687
…		…
508	no warnings;	690	no warnings;
509	use strict;	691	use strict;
510		692
511	use Carp;	693	use Carp;
512		694
513	our $VERSION = '3.3';	695	our $VERSION = '3.4';
514	our $MODEL;	696	our $MODEL;
515		697
516	our $AUTOLOAD;	698	our $AUTOLOAD;
517	our @ISA;	699	our @ISA;
518		700
519	our $verbose = $ENV{PERL_ANYEVENT_VERBOSE}*1;	701	our $verbose = $ENV{PERL_ANYEVENT_VERBOSE}*1;
520		702
521	our @REGISTRY;	703	our @REGISTRY;
522		704
523	my @models = (	705	my @models = (
524	[Coro::EV:: => AnyEvent::Impl::CoroEV::],
525	[Coro::Event:: => AnyEvent::Impl::CoroEvent::],
526	[EV:: => AnyEvent::Impl::EV::],	706	[EV:: => AnyEvent::Impl::EV::],
527	[Event:: => AnyEvent::Impl::Event::],	707	[Event:: => AnyEvent::Impl::Event::],
528	[Glib:: => AnyEvent::Impl::Glib::],
529	[Tk:: => AnyEvent::Impl::Tk::],	708	[Tk:: => AnyEvent::Impl::Tk::],
530	[Wx:: => AnyEvent::Impl::POE::],	709	[Wx:: => AnyEvent::Impl::POE::],
531	[Prima:: => AnyEvent::Impl::POE::],	710	[Prima:: => AnyEvent::Impl::POE::],
532	[AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl::],	711	[AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl::],
533	# everything below here will not be autoprobed as the pureperl backend should work everywhere	712	# everything below here will not be autoprobed as the pureperl backend should work everywhere
		713	[Glib:: => AnyEvent::Impl::Glib::],
534	[Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy	714	[Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy
535	[Qt:: => AnyEvent::Impl::Qt::], # requires special main program	715	[Qt:: => AnyEvent::Impl::Qt::], # requires special main program
536	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza	716	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza
537	);	717	);
538		718
539	our %method = map +($_ => 1), qw(io timer signal child condvar broadcast wait one_event DESTROY);	719	our %method = map +($_ => 1), qw(io timer signal child condvar one_event DESTROY);
		720
		721	our @on_detect;
		722
		723	sub on_detect(&) {
		724	if ($MODEL) {
		725	$_[0]->();
		726	} else {
		727	push @on_detect, $_[0];
		728	}
		729	}
540		730
541	sub detect() {	731	sub detect() {
542	unless ($MODEL) {	732	unless ($MODEL) {
543	no strict 'refs';	733	no strict 'refs';
544		734
…		…
578	last;	768	last;
579	}	769	}
580	}	770	}
581		771
582	$MODEL	772	$MODEL
583	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.";	773	or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV, Event or Glib.";
584	}	774	}
585	}	775	}
586		776
587	unshift @ISA, $MODEL;	777	unshift @ISA, $MODEL;
588	push @{"$MODEL\::ISA"}, "AnyEvent::Base";	778	push @{"$MODEL\::ISA"}, "AnyEvent::Base";
		779
		780	(shift @on_detect)->() while @on_detect;
589	}	781	}
590		782
591	$MODEL	783	$MODEL
592	}	784	}
593		785
…		…
1041	file descriptor is dup()ed for each watcher. This shows that the dup()	1233	file descriptor is dup()ed for each watcher. This shows that the dup()
1042	employed by some adaptors is not a big performance issue (it does incur a	1234	employed by some adaptors is not a big performance issue (it does incur a
1043	hidden memory cost inside the kernel which is not reflected in the figures	1235	hidden memory cost inside the kernel which is not reflected in the figures
1044	above).	1236	above).
1045		1237
1046	C<POE>, regardless of underlying event loop (whether using its pure	1238	C<POE>, regardless of underlying event loop (whether using its pure perl
1047	perl select-based backend or the Event module, the POE-EV backend	1239	select-based backend or the Event module, the POE-EV backend couldn't
1048	couldn't be tested because it wasn't working) shows abysmal performance	1240	be tested because it wasn't working) shows abysmal performance and
1049	and memory usage: Watchers use almost 30 times as much memory as	1241	memory usage with AnyEvent: Watchers use almost 30 times as much memory
1050	EV watchers, and 10 times as much memory as Event (the high memory	1242	as EV watchers, and 10 times as much memory as Event (the high memory
1051	requirements are caused by requiring a session for each watcher). Watcher	1243	requirements are caused by requiring a session for each watcher). Watcher
1052	invocation speed is almost 900 times slower than with AnyEvent's pure perl	1244	invocation speed is almost 900 times slower than with AnyEvent's pure perl
		1245	implementation.
		1246
1053	implementation. The design of the POE adaptor class in AnyEvent can not	1247	The design of the POE adaptor class in AnyEvent can not really account
1054	really account for this, as session creation overhead is small compared	1248	for the performance issues, though, as session creation overhead is
1055	to execution of the state machine, which is coded pretty optimally within	1249	small compared to execution of the state machine, which is coded pretty
1056	L<AnyEvent::Impl::POE>. POE simply seems to be abysmally slow.	1250	optimally within L<AnyEvent::Impl::POE> (and while everybody agrees that
		1251	using multiple sessions is not a good approach, especially regarding
		1252	memory usage, even the author of POE could not come up with a faster
		1253	design).
1057		1254
1058	=head3 Summary	1255	=head3 Summary
1059		1256
1060	=over 4	1257	=over 4
1061		1258
…		…
1140		1337
1141	=head3 Summary	1338	=head3 Summary
1142		1339
1143	=over 4	1340	=over 4
1144		1341
1145	=item * The pure perl implementation performs extremely well, considering	1342	=item * The pure perl implementation performs extremely well.
1146	that it uses select.
1147		1343
1148	=item * Avoid Glib or POE in large projects where performance matters.	1344	=item * Avoid Glib or POE in large projects where performance matters.
1149		1345
1150	=back	1346	=back
1151		1347
…		…
1180	speed most when you have lots of watchers, not when you only have a few of	1376	speed most when you have lots of watchers, not when you only have a few of
1181	them).	1377	them).
1182		1378
1183	EV is again fastest.	1379	EV is again fastest.
1184		1380
1185	The C-based event loops Event and Glib come in second this time, as the	1381	Perl again comes second. It is noticably faster than the C-based event
1186	overhead of running an iteration is much smaller in C than in Perl (little	1382	loops Event and Glib, although the difference is too small to really
1187	code to execute in the inner loop, and perl's function calling overhead is	1383	matter.
1188	high, and updating all the data structures is costly).
1189
1190	The pure perl event loop is much slower, but still competitive.
1191		1384
1192	POE also performs much better in this case, but is is still far behind the	1385	POE also performs much better in this case, but is is still far behind the
1193	others.	1386	others.
1194		1387
1195	=head3 Summary	1388	=head3 Summary
…		…
1203		1396
1204		1397
1205	=head1 FORK	1398	=head1 FORK
1206		1399
1207	Most event libraries are not fork-safe. The ones who are usually are	1400	Most event libraries are not fork-safe. The ones who are usually are
1208	because they are so inefficient. Only L<EV> is fully fork-aware.	1401	because they rely on inefficient but fork-safe C<select> or C<poll>
		1402	calls. Only L<EV> is fully fork-aware.
1209		1403
1210	If you have to fork, you must either do so I<before> creating your first	1404	If you have to fork, you must either do so I<before> creating your first
1211	watcher OR you must not use AnyEvent at all in the child.	1405	watcher OR you must not use AnyEvent at all in the child.
1212		1406
1213		1407
…		…
1225		1419
1226	BEGIN { delete $ENV{PERL_ANYEVENT_MODEL} }	1420	BEGIN { delete $ENV{PERL_ANYEVENT_MODEL} }
1227		1421
1228	use AnyEvent;	1422	use AnyEvent;
1229		1423
		1424	Similar considerations apply to $ENV{PERL_ANYEVENT_VERBOSE}, as that can
		1425	be used to probe what backend is used and gain other information (which is
		1426	probably even less useful to an attacker than PERL_ANYEVENT_MODEL).
		1427
1230		1428
1231	=head1 SEE ALSO	1429	=head1 SEE ALSO
1232		1430
1233	Event modules: L<Coro::EV>, L<EV>, L<EV::Glib>, L<Glib::EV>,	1431	Event modules: L<EV>, L<EV::Glib>, L<Glib::EV>, L<Event>, L<Glib::Event>,
1234	L<Coro::Event>, L<Event>, L<Glib::Event>, L<Glib>, L<Coro>, L<Tk>,
1235	L<Event::Lib>, L<Qt>, L<POE>.	1432	L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>.
1236		1433
1237	Implementations: L<AnyEvent::Impl::CoroEV>, L<AnyEvent::Impl::EV>,	1434	Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>,
1238	L<AnyEvent::Impl::CoroEvent>, L<AnyEvent::Impl::Event>, L<AnyEvent::Impl::Glib>,	1435	L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>,
1239	L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>, L<AnyEvent::Impl::EventLib>,	1436	L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>,
1240	L<AnyEvent::Impl::Qt>, L<AnyEvent::Impl::POE>.	1437	L<AnyEvent::Impl::POE>.
		1438
		1439	Coroutine support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>, L<Coro::Event>,
1241		1440
1242	Nontrivial usage examples: L<Net::FCP>, L<Net::XMPP2>.	1441	Nontrivial usage examples: L<Net::FCP>, L<Net::XMPP2>.
1243		1442
1244		1443
1245	=head1 AUTHOR	1444	=head1 AUTHOR

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Comparing AnyEvent/lib/AnyEvent.pm (file contents): Revision 1.100 by elmex, Sun Apr 27 19:15:43 2008 UTC vs. Revision 1.109 by root, Sat May 10 00:45:18 2008 UTC

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Comparing AnyEvent/lib/AnyEvent.pm (file contents):
Revision 1.100 by elmex, Sun Apr 27 19:15:43 2008 UTC vs.
Revision 1.109 by root, Sat May 10 00:45:18 2008 UTC