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

Comparing AnyEvent/lib/AnyEvent.pm (file contents):
Revision 1.105 by root, Thu May 1 12:35:54 2008 UTC vs.
Revision 1.142 by root, Tue May 27 02:34:30 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 ->broadcast	21	$w->recv; # enters "main loop" till $condvar gets ->send
21	$w->broadcast; # 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?
…		…
48	isn't itself. What's worse, all the potential users of your module are	48	isn't itself. What's worse, all the potential users of your module are
49	I<also> forced to use the same event loop you use.	49	I<also> forced to use the same event loop you use.
50		50
51	AnyEvent is different: AnyEvent + POE works fine. AnyEvent + Glib works	51	AnyEvent is different: AnyEvent + POE works fine. AnyEvent + Glib works
52	fine. AnyEvent + Tk works fine etc. etc. but none of these work together	52	fine. AnyEvent + Tk works fine etc. etc. but none of these work together
53	with the rest: POE + IO::Async? no go. Tk + Event? no go. Again: if	53	with the rest: POE + IO::Async? No go. Tk + Event? No go. Again: if
54	your module uses one of those, every user of your module has to use it,	54	your module uses one of those, every user of your module has to use it,
55	too. But if your module uses AnyEvent, it works transparently with all	55	too. But if your module uses AnyEvent, it works transparently with all
56	event models it supports (including stuff like POE and IO::Async, as long	56	event models it supports (including stuff like POE and IO::Async, as long
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, AnyEvent comes with a big (and fully optional!) toolbox
		68	of useful functionality, such as an asynchronous DNS resolver, 100%
		69	non-blocking connects (even with TLS/SSL, IPv6 and on broken platforms
		70	such as Windows) and lots of real-world knowledge and workarounds for
		71	platform bugs and differences.
		72
67	Of course, if you want lots of policy (this can arguably be somewhat	73	Now, if you I<do 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	74	useful) and you want to force your users to use the one and only event
69	model, you should I<not> use this module.	75	model, you should I<not> use this module.
70		76
71	=head1 DESCRIPTION	77	=head1 DESCRIPTION
72		78
…		…
78	The interface itself is vaguely similar, but not identical to the L<Event>	84	The interface itself is vaguely similar, but not identical to the L<Event>
79	module.	85	module.
80		86
81	During the first call of any watcher-creation method, the module tries	87	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	88	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>,	89	following modules is already loaded: L<EV>,
84	L<Event>, L<Glib>, L<AnyEvent::Impl::Perl>, L<Tk>, L<Event::Lib>, L<Qt>,	90	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	91	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	92	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	93	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	94	be successfully loaded will be used. If, after this, still none could be
…		…
102	starts using it, all bets are off. Maybe you should tell their authors to	108	starts using it, all bets are off. Maybe you should tell their authors to
103	use AnyEvent so their modules work together with others seamlessly...	109	use AnyEvent so their modules work together with others seamlessly...
104		110
105	The pure-perl implementation of AnyEvent is called	111	The pure-perl implementation of AnyEvent is called
106	C<AnyEvent::Impl::Perl>. Like other event modules you can load it	112	C<AnyEvent::Impl::Perl>. Like other event modules you can load it
107	explicitly.	113	explicitly and enjoy the high availability of that event loop :)
108		114
109	=head1 WATCHERS	115	=head1 WATCHERS
110		116
111	AnyEvent has the central concept of a I<watcher>, which is an object that	117	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	118	stores relevant data for each kind of event you are waiting for, such as
113	the callback to call, the filehandle to watch, etc.	119	the callback to call, the file handle to watch, etc.
114		120
115	These watchers are normal Perl objects with normal Perl lifetime. After	121	These watchers are normal Perl objects with normal Perl lifetime. After
116	creating a watcher it will immediately "watch" for events and invoke the	122	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	123	callback when the event occurs (of course, only when the event model
118	is in control).	124	is in control).
…		…
237		243
238	Although the callback might get passed parameters, their value and	244	Although the callback might get passed parameters, their value and
239	presence is undefined and you cannot rely on them. Portable AnyEvent	245	presence is undefined and you cannot rely on them. Portable AnyEvent
240	callbacks cannot use arguments passed to signal watcher callbacks.	246	callbacks cannot use arguments passed to signal watcher callbacks.
241		247
242	Multiple signal occurances can be clumped together into one callback	248	Multiple signal occurrences can be clumped together into one callback
243	invocation, and callback invocation will be synchronous. synchronous means	249	invocation, and callback invocation will be synchronous. Synchronous means
244	that it might take a while until the signal gets handled by the process,	250	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.	251	but it is guaranteed not to interrupt any other callbacks.
246		252
247	The main advantage of using these watchers is that you can share a signal	253	The main advantage of using these watchers is that you can share a signal
248	between multiple watchers.	254	between multiple watchers.
249		255
250	This watcher might use C<%SIG>, so programs overwriting those signals	256	This watcher might use C<%SIG>, so programs overwriting those signals
…		…
279		285
280	Example: fork a process and wait for it	286	Example: fork a process and wait for it
281		287
282	my $done = AnyEvent->condvar;	288	my $done = AnyEvent->condvar;
283		289
284	AnyEvent::detect; # force event module to be initialised
285
286	my $pid = fork or exit 5;	290	my $pid = fork or exit 5;
287		291
288	my $w = AnyEvent->child (	292	my $w = AnyEvent->child (
289	pid => $pid,	293	pid => $pid,
290	cb => sub {	294	cb => sub {
291	my ($pid, $status) = @_;	295	my ($pid, $status) = @_;
292	warn "pid $pid exited with status $status";	296	warn "pid $pid exited with status $status";
293	$done->broadcast;	297	$done->send;
294	},	298	},
295	);	299	);
296		300
297	# do something else, then wait for process exit	301	# do something else, then wait for process exit
298	$done->wait;	302	$done->recv;
299		303
300	=head2 CONDITION VARIABLES	304	=head2 CONDITION VARIABLES
301		305
302	If you are familiar with some event loops you will know that all of them	306	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	307	require you to run some blocking "loop", "run" or similar function that
…		…
312	Condition variables can be created by calling the C<< AnyEvent->condvar	316	Condition variables can be created by calling the C<< AnyEvent->condvar
313	>> method, usually without arguments. The only argument pair allowed is	317	>> method, usually without arguments. The only argument pair allowed is
314	C<cb>, which specifies a callback to be called when the condition variable	318	C<cb>, which specifies a callback to be called when the condition variable
315	becomes true.	319	becomes true.
316		320
317	After creation, the conditon variable is "false" until it becomes "true"	321	After creation, the condition variable is "false" until it becomes "true"
318	by calling the C<broadcast> method.	322	by calling the C<send> method (or calling the condition variable as if it
		323	were a callback, read about the caveats in the description for the C<<
		324	->send >> method).
319		325
320	Condition variables are similar to callbacks, except that you can	326	Condition variables are similar to callbacks, except that you can
321	optionally wait for them. They can also be called merge points - points	327	optionally wait for them. They can also be called merge points - points
322	in time where multiple outstandign events have been processed. And yet	328	in time where multiple outstanding events have been processed. And yet
323	another way to call them is transations - each condition variable can be	329	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	330	used to represent a transaction, which finishes at some point and delivers
325	a result.	331	a result.
326		332
327	Condition variables are very useful to signal that something has finished,	333	Condition variables are very useful to signal that something has finished,
328	for example, if you write a module that does asynchronous http requests,	334	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	335	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	336	availability of results. The user can either act when the callback is
331	called or can synchronously C<< ->wait >> for the results.	337	called or can synchronously C<< ->recv >> for the results.
332		338
333	You can also use them to simulate traditional event loops - for example,	339	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	340	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	341	could C<< ->recv >> in your main program until the user clicks the Quit
336	button of your app, which would C<< ->broadcast >> the "quit" event.	342	button of your app, which would C<< ->send >> the "quit" event.
337		343
338	Note that condition variables recurse into the event loop - if you have	344	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	345	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	346	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,	347	you should avoid making a blocking wait yourself, at least in callbacks,
342	as this asks for trouble.	348	as this asks for trouble.
343		349
344	Condition variables are represented by hash refs in perl, and the keys	350	Condition variables are represented by hash refs in perl, and the keys
…		…
346	easy (it is often useful to build your own transaction class on top of	352	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	353	AnyEvent). To subclass, use C<AnyEvent::CondVar> as base class and call
348	it's C<new> method in your own C<new> method.	354	it's C<new> method in your own C<new> method.
349		355
350	There are two "sides" to a condition variable - the "producer side" which	356	There are two "sides" to a condition variable - the "producer side" which
351	eventually calls C<< -> broadcast >>, and the "consumer side", which waits	357	eventually calls C<< -> send >>, and the "consumer side", which waits
352	for the broadcast to occur.	358	for the send to occur.
353		359
354	Example:	360	Example: wait for a timer.
355		361
356	# wait till the result is ready	362	# wait till the result is ready
357	my $result_ready = AnyEvent->condvar;	363	my $result_ready = AnyEvent->condvar;
358		364
359	# do something such as adding a timer	365	# do something such as adding a timer
360	# or socket watcher the calls $result_ready->broadcast	366	# or socket watcher the calls $result_ready->send
361	# when the "result" is ready.	367	# when the "result" is ready.
362	# in this case, we simply use a timer:	368	# in this case, we simply use a timer:
363	my $w = AnyEvent->timer (	369	my $w = AnyEvent->timer (
364	after => 1,	370	after => 1,
365	cb => sub { $result_ready->broadcast },	371	cb => sub { $result_ready->send },
366	);	372	);
367		373
368	# this "blocks" (while handling events) till the callback	374	# this "blocks" (while handling events) till the callback
369	# calls broadcast	375	# calls send
370	$result_ready->wait;	376	$result_ready->recv;
		377
		378	Example: wait for a timer, but take advantage of the fact that
		379	condition variables are also code references.
		380
		381	my $done = AnyEvent->condvar;
		382	my $delay = AnyEvent->timer (after => 5, cb => $done);
		383	$done->recv;
371		384
372	=head3 METHODS FOR PRODUCERS	385	=head3 METHODS FOR PRODUCERS
373		386
374	These methods should only be used by the producing side, i.e. the	387	These methods should only be used by the producing side, i.e. the
375	code/module that eventually broadcasts the signal. Note that it is also	388	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	389	the producer side which creates the condvar in most cases, but it isn't
377	uncommon for the consumer to create it as well.	390	uncommon for the consumer to create it as well.
378		391
379	=over 4	392	=over 4
380		393
381	=item $cv->broadcast (...)	394	=item $cv->send (...)
382		395
383	Flag the condition as ready - a running C<< ->wait >> and all further	396	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	397	calls to C<recv> will (eventually) return after this method has been
385	called. If nobody is waiting the broadcast will be remembered.	398	called. If nobody is waiting the send will be remembered.
386		399
387	If a callback has been set on the condition variable, it is called	400	If a callback has been set on the condition variable, it is called
388	immediately from within broadcast.	401	immediately from within send.
389		402
390	Any arguments passed to the C<broadcast> call will be returned by all	403	Any arguments passed to the C<send> call will be returned by all
391	future C<< ->wait >> calls.	404	future C<< ->recv >> calls.
		405
		406	Condition variables are overloaded so one can call them directly
		407	(as a code reference). Calling them directly is the same as calling
		408	C<send>. Note, however, that many C-based event loops do not handle
		409	overloading, so as tempting as it may be, passing a condition variable
		410	instead of a callback does not work. Both the pure perl and EV loops
		411	support overloading, however, as well as all functions that use perl to
		412	invoke a callback (as in L<AnyEvent::Socket> and L<AnyEvent::DNS> for
		413	example).
392		414
393	=item $cv->croak ($error)	415	=item $cv->croak ($error)
394		416
395	Similar to broadcast, but causes all call's wait C<< ->wait >> to invoke	417	Similar to send, but causes all call's to C<< ->recv >> to invoke
396	C<Carp::croak> with the given error message/object/scalar.	418	C<Carp::croak> with the given error message/object/scalar.
397		419
398	This can be used to signal any errors to the condition variable	420	This can be used to signal any errors to the condition variable
399	user/consumer.	421	user/consumer.
400		422
401	=item $cv->begin ([group callback])	423	=item $cv->begin ([group callback])
402		424
403	=item $cv->end	425	=item $cv->end
		426
		427	These two methods are EXPERIMENTAL and MIGHT CHANGE.
404		428
405	These two methods can be used to combine many transactions/events into	429	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	430	one. For example, a function that pings many hosts in parallel might want
407	to use a condition variable for the whole process.	431	to use a condition variable for the whole process.
408		432
409	Every call to C<< ->begin >> will increment a counter, and every call to	433	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	434	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	435	>>, the (last) callback passed to C<begin> will be executed. That callback
412	is I<supposed> to call C<< ->broadcast >>, but that is not required. If no	436	is I<supposed> to call C<< ->send >>, but that is not required. If no
413	callback was set, C<broadcast> will be called without any arguments.	437	callback was set, C<send> will be called without any arguments.
414		438
415	Let's clarify this with the ping example:	439	Let's clarify this with the ping example:
416		440
417	my $cv = AnyEvent->condvar;	441	my $cv = AnyEvent->condvar;
418		442
419	my %result;	443	my %result;
420	$cv->begin (sub { $cv->broadcast (\%result) });	444	$cv->begin (sub { $cv->send (\%result) });
421		445
422	for my $host (@list_of_hosts) {	446	for my $host (@list_of_hosts) {
423	$cv->begin;	447	$cv->begin;
424	ping_host_then_call_callback $host, sub {	448	ping_host_then_call_callback $host, sub {
425	$result{$host} = ...;	449	$result{$host} = ...;
…		…
428	}	452	}
429		453
430	$cv->end;	454	$cv->end;
431		455
432	This code fragment supposedly pings a number of hosts and calls	456	This code fragment supposedly pings a number of hosts and calls
433	C<broadcast> after results for all then have have been gathered - in any	457	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	458	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	459	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	460	it. Since C<begin> and C<end> only maintain a counter, the order in which
437	results arrive is not relevant.	461	results arrive is not relevant.
438		462
439	There is an additional bracketing call to C<begin> and C<end> outside the	463	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	464	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	465	to be called once the counter reaches C<0>, and second, it ensures that
442	broadcast is called even when C<no> hosts are being pinged (the loop	466	C<send> is called even when C<no> hosts are being pinged (the loop
443	doesn't execute once).	467	doesn't execute once).
444		468
445	This is the general pattern when you "fan out" into multiple subrequests:	469	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>	470	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	471	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>.	472	C<begin> and for each subrequest you finish, call C<end>.
449		473
450	=back	474	=back
451		475
452	=head3 METHODS FOR CONSUMERS	476	=head3 METHODS FOR CONSUMERS
453		477
454	These methods should only be used by the consuming side, i.e. the	478	These methods should only be used by the consuming side, i.e. the
455	code awaits the condition.	479	code awaits the condition.
456		480
457	=item $cv->wait	481	=over 4
458		482
		483	=item $cv->recv
		484
459	Wait (blocking if necessary) until the C<< ->broadcast >> or C<< ->croak	485	Wait (blocking if necessary) until the C<< ->send >> or C<< ->croak
460	>> methods have been called on c<$cv>, while servicing other watchers	486	>> methods have been called on c<$cv>, while servicing other watchers
461	normally.	487	normally.
462		488
463	You can only wait once on a condition - additional calls are valid but	489	You can only wait once on a condition - additional calls are valid but
464	will return immediately.	490	will return immediately.
465		491
466	If an error condition has been set by calling C<< ->croak >>, then this	492	If an error condition has been set by calling C<< ->croak >>, then this
467	function will call C<croak>.	493	function will call C<croak>.
468		494
469	In list context, all parameters passed to C<broadcast> will be returned,	495	In list context, all parameters passed to C<send> will be returned,
470	in scalar context only the first one will be returned.	496	in scalar context only the first one will be returned.
471		497
472	Not all event models support a blocking wait - some die in that case	498	Not all event models support a blocking wait - some die in that case
473	(programs might want to do that to stay interactive), so I<if you are	499	(programs might want to do that to stay interactive), so I<if you are
474	using this from a module, never require a blocking wait>, but let the	500	using this from a module, never require a blocking wait>, but let the
475	caller decide whether the call will block or not (for example, by coupling	501	caller decide whether the call will block or not (for example, by coupling
476	condition variables with some kind of request results and supporting	502	condition variables with some kind of request results and supporting
477	callbacks so the caller knows that getting the result will not block,	503	callbacks so the caller knows that getting the result will not block,
478	while still suppporting blocking waits if the caller so desires).	504	while still supporting blocking waits if the caller so desires).
479		505
480	Another reason I<never> to C<< ->wait >> in a module is that you cannot	506	Another reason I<never> to C<< ->recv >> in a module is that you cannot
481	sensibly have two C<< ->wait >>'s in parallel, as that would require	507	sensibly have two C<< ->recv >>'s in parallel, as that would require
482	multiple interpreters or coroutines/threads, none of which C<AnyEvent>	508	multiple interpreters or coroutines/threads, none of which C<AnyEvent>
483	can supply (the coroutine-aware backends L<AnyEvent::Impl::CoroEV> and	509	can supply.
484	L<AnyEvent::Impl::CoroEvent> explicitly support concurrent C<< ->wait >>'s
485	from different coroutines, however).
486		510
		511	The L<Coro> module, however, I<can> and I<does> supply coroutines and, in
		512	fact, L<Coro::AnyEvent> replaces AnyEvent's condvars by coroutine-safe
		513	versions and also integrates coroutines into AnyEvent, making blocking
		514	C<< ->recv >> calls perfectly safe as long as they are done from another
		515	coroutine (one that doesn't run the event loop).
		516
487	You can ensure that C<< -wait >> never blocks by setting a callback and	517	You can ensure that C<< -recv >> never blocks by setting a callback and
488	only calling C<< ->wait >> from within that callback (or at a later	518	only calling C<< ->recv >> from within that callback (or at a later
489	time). This will work even when the event loop does not support blocking	519	time). This will work even when the event loop does not support blocking
490	waits otherwise.	520	waits otherwise.
		521
		522	=item $bool = $cv->ready
		523
		524	Returns true when the condition is "true", i.e. whether C<send> or
		525	C<croak> have been called.
		526
		527	=item $cb = $cv->cb ([new callback])
		528
		529	This is a mutator function that returns the callback set and optionally
		530	replaces it before doing so.
		531
		532	The callback will be called when the condition becomes "true", i.e. when
		533	C<send> or C<croak> are called. Calling C<recv> inside the callback
		534	or at any later time is guaranteed not to block.
491		535
492	=back	536	=back
493		537
494	=head1 GLOBAL VARIABLES AND FUNCTIONS	538	=head1 GLOBAL VARIABLES AND FUNCTIONS
495		539
…		…
503	C<AnyEvent::Impl:xxx> modules, but can be any other class in the case	547	C<AnyEvent::Impl:xxx> modules, but can be any other class in the case
504	AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode>).	548	AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode>).
505		549
506	The known classes so far are:	550	The known classes so far are:
507		551
508	AnyEvent::Impl::CoroEV based on Coro::EV, best choice.
509	AnyEvent::Impl::CoroEvent based on Coro::Event, second best choice.
510	AnyEvent::Impl::EV based on EV (an interface to libev, best choice).	552	AnyEvent::Impl::EV based on EV (an interface to libev, best choice).
511	AnyEvent::Impl::Event based on Event, second best choice.	553	AnyEvent::Impl::Event based on Event, second best choice.
512	AnyEvent::Impl::Perl pure-perl implementation, fast and portable.	554	AnyEvent::Impl::Perl pure-perl implementation, fast and portable.
513	AnyEvent::Impl::Glib based on Glib, third-best choice.	555	AnyEvent::Impl::Glib based on Glib, third-best choice.
514	AnyEvent::Impl::Tk based on Tk, very bad choice.	556	AnyEvent::Impl::Tk based on Tk, very bad choice.
…		…
531	Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model	573	Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model
532	if necessary. You should only call this function right before you would	574	if necessary. You should only call this function right before you would
533	have created an AnyEvent watcher anyway, that is, as late as possible at	575	have created an AnyEvent watcher anyway, that is, as late as possible at
534	runtime.	576	runtime.
535		577
		578	=item $guard = AnyEvent::post_detect { BLOCK }
		579
		580	Arranges for the code block to be executed as soon as the event model is
		581	autodetected (or immediately if this has already happened).
		582
		583	If called in scalar or list context, then it creates and returns an object
		584	that automatically removes the callback again when it is destroyed. See
		585	L<Coro::BDB> for a case where this is useful.
		586
		587	=item @AnyEvent::post_detect
		588
		589	If there are any code references in this array (you can C<push> to it
		590	before or after loading AnyEvent), then they will called directly after
		591	the event loop has been chosen.
		592
		593	You should check C<$AnyEvent::MODEL> before adding to this array, though:
		594	if it contains a true value then the event loop has already been detected,
		595	and the array will be ignored.
		596
		597	Best use C<AnyEvent::post_detect { BLOCK }> instead.
		598
536	=back	599	=back
537		600
538	=head1 WHAT TO DO IN A MODULE	601	=head1 WHAT TO DO IN A MODULE
539		602
540	As a module author, you should C<use AnyEvent> and call AnyEvent methods	603	As a module author, you should C<use AnyEvent> and call AnyEvent methods
…		…
543	Be careful when you create watchers in the module body - AnyEvent will	606	Be careful when you create watchers in the module body - AnyEvent will
544	decide which event module to use as soon as the first method is called, so	607	decide which event module to use as soon as the first method is called, so
545	by calling AnyEvent in your module body you force the user of your module	608	by calling AnyEvent in your module body you force the user of your module
546	to load the event module first.	609	to load the event module first.
547		610
548	Never call C<< ->wait >> on a condition variable unless you I<know> that	611	Never call C<< ->recv >> on a condition variable unless you I<know> that
549	the C<< ->broadcast >> method has been called on it already. This is	612	the C<< ->send >> method has been called on it already. This is
550	because it will stall the whole program, and the whole point of using	613	because it will stall the whole program, and the whole point of using
551	events is to stay interactive.	614	events is to stay interactive.
552		615
553	It is fine, however, to call C<< ->wait >> when the user of your module	616	It is fine, however, to call C<< ->recv >> when the user of your module
554	requests it (i.e. if you create a http request object ad have a method	617	requests it (i.e. if you create a http request object ad have a method
555	called C<results> that returns the results, it should call C<< ->wait >>	618	called C<results> that returns the results, it should call C<< ->recv >>
556	freely, as the user of your module knows what she is doing. always).	619	freely, as the user of your module knows what she is doing. always).
557		620
558	=head1 WHAT TO DO IN THE MAIN PROGRAM	621	=head1 WHAT TO DO IN THE MAIN PROGRAM
559		622
560	There will always be a single main program - the only place that should	623	There will always be a single main program - the only place that should
…		…
562		625
563	If it doesn't care, it can just "use AnyEvent" and use it itself, or not	626	If it doesn't care, it can just "use AnyEvent" and use it itself, or not
564	do anything special (it does not need to be event-based) and let AnyEvent	627	do anything special (it does not need to be event-based) and let AnyEvent
565	decide which implementation to chose if some module relies on it.	628	decide which implementation to chose if some module relies on it.
566		629
567	If the main program relies on a specific event model. For example, in	630	If the main program relies on a specific event model - for example, in
568	Gtk2 programs you have to rely on the Glib module. You should load the	631	Gtk2 programs you have to rely on the Glib module - you should load the
569	event module before loading AnyEvent or any module that uses it: generally	632	event module before loading AnyEvent or any module that uses it: generally
570	speaking, you should load it as early as possible. The reason is that	633	speaking, you should load it as early as possible. The reason is that
571	modules might create watchers when they are loaded, and AnyEvent will	634	modules might create watchers when they are loaded, and AnyEvent will
572	decide on the event model to use as soon as it creates watchers, and it	635	decide on the event model to use as soon as it creates watchers, and it
573	might chose the wrong one unless you load the correct one yourself.	636	might chose the wrong one unless you load the correct one yourself.
574		637
575	You can chose to use a rather inefficient pure-perl implementation by	638	You can chose to use a pure-perl implementation by loading the
576	loading the C<AnyEvent::Impl::Perl> module, which gives you similar	639	C<AnyEvent::Impl::Perl> module, which gives you similar behaviour
577	behaviour everywhere, but letting AnyEvent chose is generally better.	640	everywhere, but letting AnyEvent chose the model is generally better.
		641
		642	=head2 MAINLOOP EMULATION
		643
		644	Sometimes (often for short test scripts, or even standalone programs who
		645	only want to use AnyEvent), you do not want to run a specific event loop.
		646
		647	In that case, you can use a condition variable like this:
		648
		649	AnyEvent->condvar->recv;
		650
		651	This has the effect of entering the event loop and looping forever.
		652
		653	Note that usually your program has some exit condition, in which case
		654	it is better to use the "traditional" approach of storing a condition
		655	variable somewhere, waiting for it, and sending it when the program should
		656	exit cleanly.
		657
578		658
579	=head1 OTHER MODULES	659	=head1 OTHER MODULES
580		660
581	The following is a non-exhaustive list of additional modules that use	661	The following is a non-exhaustive list of additional modules that use
582	AnyEvent and can therefore be mixed easily with other AnyEvent modules	662	AnyEvent and can therefore be mixed easily with other AnyEvent modules
…		…
594		674
595	Provide read and write buffers and manages watchers for reads and writes.	675	Provide read and write buffers and manages watchers for reads and writes.
596		676
597	=item L<AnyEvent::Socket>	677	=item L<AnyEvent::Socket>
598		678
599	Provides a means to do non-blocking connects, accepts etc.	679	Provides various utility functions for (internet protocol) sockets,
		680	addresses and name resolution. Also functions to create non-blocking tcp
		681	connections or tcp servers, with IPv6 and SRV record support and more.
		682
		683	=item L<AnyEvent::DNS>
		684
		685	Provides rich asynchronous DNS resolver capabilities.
600		686
601	=item L<AnyEvent::HTTPD>	687	=item L<AnyEvent::HTTPD>
602		688
603	Provides a simple web application server framework.	689	Provides a simple web application server framework.
604
605	=item L<AnyEvent::DNS>
606
607	Provides asynchronous DNS resolver capabilities, beyond what
608	L<AnyEvent::Util> offers.
609		690
610	=item L<AnyEvent::FastPing>	691	=item L<AnyEvent::FastPing>
611		692
612	The fastest ping in the west.	693	The fastest ping in the west.
613		694
…		…
628		709
629	High level API for event-based execution flow control.	710	High level API for event-based execution flow control.
630		711
631	=item L<Coro>	712	=item L<Coro>
632		713
633	Has special support for AnyEvent.	714	Has special support for AnyEvent via L<Coro::AnyEvent>.
		715
		716	=item L<AnyEvent::AIO>, L<IO::AIO>
		717
		718	Truly asynchronous I/O, should be in the toolbox of every event
		719	programmer. AnyEvent::AIO transparently fuses IO::AIO and AnyEvent
		720	together.
		721
		722	=item L<AnyEvent::BDB>, L<BDB>
		723
		724	Truly asynchronous Berkeley DB access. AnyEvent::AIO transparently fuses
		725	IO::AIO and AnyEvent together.
634		726
635	=item L<IO::Lambda>	727	=item L<IO::Lambda>
636		728
637	The lambda approach to I/O - don't ask, look there. Can use AnyEvent.	729	The lambda approach to I/O - don't ask, look there. Can use AnyEvent.
638
639	=item L<IO::AIO>
640
641	Truly asynchronous I/O, should be in the toolbox of every event
642	programmer. Can be trivially made to use AnyEvent.
643
644	=item L<BDB>
645
646	Truly asynchronous Berkeley DB access. Can be trivially made to use
647	AnyEvent.
648		730
649	=back	731	=back
650		732
651	=cut	733	=cut
652		734
…		…
655	no warnings;	737	no warnings;
656	use strict;	738	use strict;
657		739
658	use Carp;	740	use Carp;
659		741
660	our $VERSION = '3.3';	742	our $VERSION = '4.05';
661	our $MODEL;	743	our $MODEL;
662		744
663	our $AUTOLOAD;	745	our $AUTOLOAD;
664	our @ISA;	746	our @ISA;
665		747
		748	our @REGISTRY;
		749
		750	our $WIN32;
		751
		752	BEGIN {
		753	my $win32 = ! ! ($^O =~ /mswin32/i);
		754	eval "sub WIN32(){ $win32 }";
		755	}
		756
666	our $verbose = $ENV{PERL_ANYEVENT_VERBOSE}*1;	757	our $verbose = $ENV{PERL_ANYEVENT_VERBOSE}*1;
667		758
668	our @REGISTRY;	759	our %PROTOCOL; # (ipv4\|ipv6) => (1\|2), higher numbers are preferred
		760
		761	{
		762	my $idx;
		763	$PROTOCOL{$_} = ++$idx
		764	for reverse split /\s,\s/,
		765	$ENV{PERL_ANYEVENT_PROTOCOLS} \|\| "ipv4,ipv6";
		766	}
669		767
670	my @models = (	768	my @models = (
671	[Coro::EV:: => AnyEvent::Impl::CoroEV::],
672	[Coro::Event:: => AnyEvent::Impl::CoroEvent::],
673	[EV:: => AnyEvent::Impl::EV::],	769	[EV:: => AnyEvent::Impl::EV::],
674	[Event:: => AnyEvent::Impl::Event::],	770	[Event:: => AnyEvent::Impl::Event::],
675	[Tk:: => AnyEvent::Impl::Tk::],
676	[Wx:: => AnyEvent::Impl::POE::],
677	[Prima:: => AnyEvent::Impl::POE::],
678	[AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl::],	771	[AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl::],
679	# everything below here will not be autoprobed as the pureperl backend should work everywhere	772	# everything below here will not be autoprobed
680	[Glib:: => AnyEvent::Impl::Glib::],	773	# as the pureperl backend should work everywhere
		774	# and is usually faster
		775	[Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles
		776	[Glib:: => AnyEvent::Impl::Glib::], # becomes extremely slow with many watchers
681	[Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy	777	[Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy
682	[Qt:: => AnyEvent::Impl::Qt::], # requires special main program	778	[Qt:: => AnyEvent::Impl::Qt::], # requires special main program
683	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza	779	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza
		780	[Wx:: => AnyEvent::Impl::POE::],
		781	[Prima:: => AnyEvent::Impl::POE::],
684	);	782	);
685		783
686	our %method = map +($_ => 1), qw(io timer signal child condvar broadcast wait one_event DESTROY);	784	our %method = map +($_ => 1), qw(io timer signal child condvar one_event DESTROY);
		785
		786	our @post_detect;
		787
		788	sub post_detect(&) {
		789	my ($cb) = @_;
		790
		791	if ($MODEL) {
		792	$cb->();
		793
		794	1
		795	} else {
		796	push @post_detect, $cb;
		797
		798	defined wantarray
		799	? bless \$cb, "AnyEvent::Util::PostDetect"
		800	: ()
		801	}
		802	}
		803
		804	sub AnyEvent::Util::PostDetect::DESTROY {
		805	@post_detect = grep $_ != ${$_[0]}, @post_detect;
		806	}
687		807
688	sub detect() {	808	sub detect() {
689	unless ($MODEL) {	809	unless ($MODEL) {
690	no strict 'refs';	810	no strict 'refs';
		811	local $SIG{__DIE__};
691		812
692	if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) {	813	if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) {
693	my $model = "AnyEvent::Impl::$1";	814	my $model = "AnyEvent::Impl::$1";
694	if (eval "require $model") {	815	if (eval "require $model") {
695	$MODEL = $model;	816	$MODEL = $model;
…		…
725	last;	846	last;
726	}	847	}
727	}	848	}
728		849
729	$MODEL	850	$MODEL
730	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.";	851	or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV, Event or Glib.";
731	}	852	}
732	}	853	}
733		854
734	unshift @ISA, $MODEL;	855	unshift @ISA, $MODEL;
735	push @{"$MODEL\::ISA"}, "AnyEvent::Base";	856	push @{"$MODEL\::ISA"}, "AnyEvent::Base";
		857
		858	(shift @post_detect)->() while @post_detect;
736	}	859	}
737		860
738	$MODEL	861	$MODEL
739	}	862	}
740		863
…		…
750	$class->$func (@_);	873	$class->$func (@_);
751	}	874	}
752		875
753	package AnyEvent::Base;	876	package AnyEvent::Base;
754		877
755	# default implementation for ->condvar, ->wait, ->broadcast	878	# default implementation for ->condvar
756		879
757	sub condvar {	880	sub condvar {
758	bless \my $flag, "AnyEvent::Base::CondVar"	881	bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, AnyEvent::CondVar::
759	}
760
761	sub AnyEvent::Base::CondVar::broadcast {
762	${$_[0]}++;
763	}
764
765	sub AnyEvent::Base::CondVar::wait {
766	AnyEvent->one_event while !${$_[0]};
767	}	882	}
768		883
769	# default implementation for ->signal	884	# default implementation for ->signal
770		885
771	our %SIG_CB;	886	our %SIG_CB;
…		…
824	or Carp::croak "required option 'pid' is missing";	939	or Carp::croak "required option 'pid' is missing";
825		940
826	$PID_CB{$pid}{$arg{cb}} = $arg{cb};	941	$PID_CB{$pid}{$arg{cb}} = $arg{cb};
827		942
828	unless ($WNOHANG) {	943	unless ($WNOHANG) {
829	$WNOHANG = eval { require POSIX; &POSIX::WNOHANG } \|\| 1;	944	$WNOHANG = eval { local $SIG{__DIE__}; require POSIX; &POSIX::WNOHANG } \|\| 1;
830	}	945	}
831		946
832	unless ($CHLD_W) {	947	unless ($CHLD_W) {
833	$CHLD_W = AnyEvent->signal (signal => 'CHLD', cb => \&_sigchld);	948	$CHLD_W = AnyEvent->signal (signal => 'CHLD', cb => \&_sigchld);
834	# child could be a zombie already, so make at least one round	949	# child could be a zombie already, so make at least one round
…		…
844	delete $PID_CB{$pid}{$cb};	959	delete $PID_CB{$pid}{$cb};
845	delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };	960	delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };
846		961
847	undef $CHLD_W unless keys %PID_CB;	962	undef $CHLD_W unless keys %PID_CB;
848	}	963	}
		964
		965	package AnyEvent::CondVar;
		966
		967	our @ISA = AnyEvent::CondVar::Base::;
		968
		969	package AnyEvent::CondVar::Base;
		970
		971	use overload
		972	'&{}' => sub { my $self = shift; sub { $self->send (@_) } },
		973	fallback => 1;
		974
		975	sub _send {
		976	# nop
		977	}
		978
		979	sub send {
		980	my $cv = shift;
		981	$cv->{_ae_sent} = [@_];
		982	(delete $cv->{_ae_cb})->($cv) if $cv->{_ae_cb};
		983	$cv->_send;
		984	}
		985
		986	sub croak {
		987	$_[0]{_ae_croak} = $_[1];
		988	$_[0]->send;
		989	}
		990
		991	sub ready {
		992	$_[0]{_ae_sent}
		993	}
		994
		995	sub _wait {
		996	AnyEvent->one_event while !$_[0]{_ae_sent};
		997	}
		998
		999	sub recv {
		1000	$_[0]->_wait;
		1001
		1002	Carp::croak $_[0]{_ae_croak} if $_[0]{_ae_croak};
		1003	wantarray ? @{ $_[0]{_ae_sent} } : $_[0]{_ae_sent}[0]
		1004	}
		1005
		1006	sub cb {
		1007	$_[0]{_ae_cb} = $_[1] if @_ > 1;
		1008	$_[0]{_ae_cb}
		1009	}
		1010
		1011	sub begin {
		1012	++$_[0]{_ae_counter};
		1013	$_[0]{_ae_end_cb} = $_[1] if @_ > 1;
		1014	}
		1015
		1016	sub end {
		1017	return if --$_[0]{_ae_counter};
		1018	&{ $_[0]{_ae_end_cb} \|\| sub { $_[0]->send } };
		1019	}
		1020
		1021	# undocumented/compatibility with pre-3.4
		1022	*broadcast = \&send;
		1023	*wait = \&_wait;
849		1024
850	=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE	1025	=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE
851		1026
852	This is an advanced topic that you do not normally need to use AnyEvent in	1027	This is an advanced topic that you do not normally need to use AnyEvent in
853	a module. This section is only of use to event loop authors who want to	1028	a module. This section is only of use to event loop authors who want to
…		…
910	model it chooses.	1085	model it chooses.
911		1086
912	=item C<PERL_ANYEVENT_MODEL>	1087	=item C<PERL_ANYEVENT_MODEL>
913		1088
914	This can be used to specify the event model to be used by AnyEvent, before	1089	This can be used to specify the event model to be used by AnyEvent, before
915	autodetection and -probing kicks in. It must be a string consisting	1090	auto detection and -probing kicks in. It must be a string consisting
916	entirely of ASCII letters. The string C<AnyEvent::Impl::> gets prepended	1091	entirely of ASCII letters. The string C<AnyEvent::Impl::> gets prepended
917	and the resulting module name is loaded and if the load was successful,	1092	and the resulting module name is loaded and if the load was successful,
918	used as event model. If it fails to load AnyEvent will proceed with	1093	used as event model. If it fails to load AnyEvent will proceed with
919	autodetection and -probing.	1094	auto detection and -probing.
920		1095
921	This functionality might change in future versions.	1096	This functionality might change in future versions.
922		1097
923	For example, to force the pure perl model (L<AnyEvent::Impl::Perl>) you	1098	For example, to force the pure perl model (L<AnyEvent::Impl::Perl>) you
924	could start your program like this:	1099	could start your program like this:
925		1100
926	PERL_ANYEVENT_MODEL=Perl perl ...	1101	PERL_ANYEVENT_MODEL=Perl perl ...
		1102
		1103	=item C<PERL_ANYEVENT_PROTOCOLS>
		1104
		1105	Used by both L<AnyEvent::DNS> and L<AnyEvent::Socket> to determine preferences
		1106	for IPv4 or IPv6. The default is unspecified (and might change, or be the result
		1107	of auto probing).
		1108
		1109	Must be set to a comma-separated list of protocols or address families,
		1110	current supported: C<ipv4> and C<ipv6>. Only protocols mentioned will be
		1111	used, and preference will be given to protocols mentioned earlier in the
		1112	list.
		1113
		1114	This variable can effectively be used for denial-of-service attacks
		1115	against local programs (e.g. when setuid), although the impact is likely
		1116	small, as the program has to handle connection errors already-
		1117
		1118	Examples: C<PERL_ANYEVENT_PROTOCOLS=ipv4,ipv6> - prefer IPv4 over IPv6,
		1119	but support both and try to use both. C<PERL_ANYEVENT_PROTOCOLS=ipv4>
		1120	- only support IPv4, never try to resolve or contact IPv6
		1121	addresses. C<PERL_ANYEVENT_PROTOCOLS=ipv6,ipv4> support either IPv4 or
		1122	IPv6, but prefer IPv6 over IPv4.
		1123
		1124	=item C<PERL_ANYEVENT_EDNS0>
		1125
		1126	Used by L<AnyEvent::DNS> to decide whether to use the EDNS0 extension
		1127	for DNS. This extension is generally useful to reduce DNS traffic, but
		1128	some (broken) firewalls drop such DNS packets, which is why it is off by
		1129	default.
		1130
		1131	Setting this variable to C<1> will cause L<AnyEvent::DNS> to announce
		1132	EDNS0 in its DNS requests.
		1133
		1134	=item C<PERL_ANYEVENT_MAX_FORKS>
		1135
		1136	The maximum number of child processes that C<AnyEvent::Util::fork_call>
		1137	will create in parallel.
927		1138
928	=back	1139	=back
929		1140
930	=head1 EXAMPLE PROGRAM	1141	=head1 EXAMPLE PROGRAM
931		1142
…		…
942	poll => 'r',	1153	poll => 'r',
943	cb => sub {	1154	cb => sub {
944	warn "io event <$_[0]>\n"; # will always output <r>	1155	warn "io event <$_[0]>\n"; # will always output <r>
945	chomp (my $input = <STDIN>); # read a line	1156	chomp (my $input = <STDIN>); # read a line
946	warn "read: $input\n"; # output what has been read	1157	warn "read: $input\n"; # output what has been read
947	$cv->broadcast if $input =~ /^q/i; # quit program if /^q/i	1158	$cv->send if $input =~ /^q/i; # quit program if /^q/i
948	},	1159	},
949	);	1160	);
950		1161
951	my $time_watcher; # can only be used once	1162	my $time_watcher; # can only be used once
952		1163
…		…
957	});	1168	});
958	}	1169	}
959		1170
960	new_timer; # create first timer	1171	new_timer; # create first timer
961		1172
962	$cv->wait; # wait until user enters /^q/i	1173	$cv->recv; # wait until user enters /^q/i
963		1174
964	=head1 REAL-WORLD EXAMPLE	1175	=head1 REAL-WORLD EXAMPLE
965		1176
966	Consider the L<Net::FCP> module. It features (among others) the following	1177	Consider the L<Net::FCP> module. It features (among others) the following
967	API calls, which are to freenet what HTTP GET requests are to http:	1178	API calls, which are to freenet what HTTP GET requests are to http:
…		…
1017	syswrite $txn->{fh}, $txn->{request}	1228	syswrite $txn->{fh}, $txn->{request}
1018	or die "connection or write error";	1229	or die "connection or write error";
1019	$txn->{w} = AnyEvent->io (fh => $txn->{fh}, poll => 'r', cb => sub { $txn->fh_ready_r });	1230	$txn->{w} = AnyEvent->io (fh => $txn->{fh}, poll => 'r', cb => sub { $txn->fh_ready_r });
1020		1231
1021	Again, C<fh_ready_r> waits till all data has arrived, and then stores the	1232	Again, C<fh_ready_r> waits till all data has arrived, and then stores the
1022	result and signals any possible waiters that the request ahs finished:	1233	result and signals any possible waiters that the request has finished:
1023		1234
1024	sysread $txn->{fh}, $txn->{buf}, length $txn->{$buf};	1235	sysread $txn->{fh}, $txn->{buf}, length $txn->{$buf};
1025		1236
1026	if (end-of-file or data complete) {	1237	if (end-of-file or data complete) {
1027	$txn->{result} = $txn->{buf};	1238	$txn->{result} = $txn->{buf};
1028	$txn->{finished}->broadcast;	1239	$txn->{finished}->send;
1029	$txb->{cb}->($txn) of $txn->{cb}; # also call callback	1240	$txb->{cb}->($txn) of $txn->{cb}; # also call callback
1030	}	1241	}
1031		1242
1032	The C<result> method, finally, just waits for the finished signal (if the	1243	The C<result> method, finally, just waits for the finished signal (if the
1033	request was already finished, it doesn't wait, of course, and returns the	1244	request was already finished, it doesn't wait, of course, and returns the
1034	data:	1245	data:
1035		1246
1036	$txn->{finished}->wait;	1247	$txn->{finished}->recv;
1037	return $txn->{result};	1248	return $txn->{result};
1038		1249
1039	The actual code goes further and collects all errors (C<die>s, exceptions)	1250	The actual code goes further and collects all errors (C<die>s, exceptions)
1040	that occured during request processing. The C<result> method detects	1251	that occurred during request processing. The C<result> method detects
1041	whether an exception as thrown (it is stored inside the $txn object)	1252	whether an exception as thrown (it is stored inside the $txn object)
1042	and just throws the exception, which means connection errors and other	1253	and just throws the exception, which means connection errors and other
1043	problems get reported tot he code that tries to use the result, not in a	1254	problems get reported tot he code that tries to use the result, not in a
1044	random callback.	1255	random callback.
1045		1256
…		…
1076		1287
1077	my $quit = AnyEvent->condvar;	1288	my $quit = AnyEvent->condvar;
1078		1289
1079	$fcp->txn_client_get ($url)->cb (sub {	1290	$fcp->txn_client_get ($url)->cb (sub {
1080	...	1291	...
1081	$quit->broadcast;	1292	$quit->send;
1082	});	1293	});
1083		1294
1084	$quit->wait;	1295	$quit->recv;
1085		1296
1086		1297
1087	=head1 BENCHMARKS	1298	=head1 BENCHMARKS
1088		1299
1089	To give you an idea of the performance and overheads that AnyEvent adds	1300	To give you an idea of the performance and overheads that AnyEvent adds
…		…
1091	of various event loops I prepared some benchmarks.	1302	of various event loops I prepared some benchmarks.
1092		1303
1093	=head2 BENCHMARKING ANYEVENT OVERHEAD	1304	=head2 BENCHMARKING ANYEVENT OVERHEAD
1094		1305
1095	Here is a benchmark of various supported event models used natively and	1306	Here is a benchmark of various supported event models used natively and
1096	through anyevent. The benchmark creates a lot of timers (with a zero	1307	through AnyEvent. The benchmark creates a lot of timers (with a zero
1097	timeout) and I/O watchers (watching STDOUT, a pty, to become writable,	1308	timeout) and I/O watchers (watching STDOUT, a pty, to become writable,
1098	which it is), lets them fire exactly once and destroys them again.	1309	which it is), lets them fire exactly once and destroys them again.
1099		1310
1100	Source code for this benchmark is found as F<eg/bench> in the AnyEvent	1311	Source code for this benchmark is found as F<eg/bench> in the AnyEvent
1101	distribution.	1312	distribution.
…		…
1118	all watchers, to avoid adding memory overhead. That means closure creation	1329	all watchers, to avoid adding memory overhead. That means closure creation
1119	and memory usage is not included in the figures.	1330	and memory usage is not included in the figures.
1120		1331
1121	I<invoke> is the time, in microseconds, used to invoke a simple	1332	I<invoke> is the time, in microseconds, used to invoke a simple
1122	callback. The callback simply counts down a Perl variable and after it was	1333	callback. The callback simply counts down a Perl variable and after it was
1123	invoked "watcher" times, it would C<< ->broadcast >> a condvar once to	1334	invoked "watcher" times, it would C<< ->send >> a condvar once to
1124	signal the end of this phase.	1335	signal the end of this phase.
1125		1336
1126	I<destroy> is the time, in microseconds, that it takes to destroy a single	1337	I<destroy> is the time, in microseconds, that it takes to destroy a single
1127	watcher.	1338	watcher.
1128		1339
…		…
1224		1435
1225	=back	1436	=back
1226		1437
1227	=head2 BENCHMARKING THE LARGE SERVER CASE	1438	=head2 BENCHMARKING THE LARGE SERVER CASE
1228		1439
1229	This benchmark atcually benchmarks the event loop itself. It works by	1440	This benchmark actually benchmarks the event loop itself. It works by
1230	creating a number of "servers": each server consists of a socketpair, a	1441	creating a number of "servers": each server consists of a socket pair, a
1231	timeout watcher that gets reset on activity (but never fires), and an I/O	1442	timeout watcher that gets reset on activity (but never fires), and an I/O
1232	watcher waiting for input on one side of the socket. Each time the socket	1443	watcher waiting for input on one side of the socket. Each time the socket
1233	watcher reads a byte it will write that byte to a random other "server".	1444	watcher reads a byte it will write that byte to a random other "server".
1234		1445
1235	The effect is that there will be a lot of I/O watchers, only part of which	1446	The effect is that there will be a lot of I/O watchers, only part of which
1236	are active at any one point (so there is a constant number of active	1447	are active at any one point (so there is a constant number of active
1237	fds for each loop iterstaion, but which fds these are is random). The	1448	fds for each loop iteration, but which fds these are is random). The
1238	timeout is reset each time something is read because that reflects how	1449	timeout is reset each time something is read because that reflects how
1239	most timeouts work (and puts extra pressure on the event loops).	1450	most timeouts work (and puts extra pressure on the event loops).
1240		1451
1241	In this benchmark, we use 10000 socketpairs (20000 sockets), of which 100	1452	In this benchmark, we use 10000 socket pairs (20000 sockets), of which 100
1242	(1%) are active. This mirrors the activity of large servers with many	1453	(1%) are active. This mirrors the activity of large servers with many
1243	connections, most of which are idle at any one point in time.	1454	connections, most of which are idle at any one point in time.
1244		1455
1245	Source code for this benchmark is found as F<eg/bench2> in the AnyEvent	1456	Source code for this benchmark is found as F<eg/bench2> in the AnyEvent
1246	distribution.	1457	distribution.
…		…
1248	=head3 Explanation of the columns	1459	=head3 Explanation of the columns
1249		1460
1250	I<sockets> is the number of sockets, and twice the number of "servers" (as	1461	I<sockets> is the number of sockets, and twice the number of "servers" (as
1251	each server has a read and write socket end).	1462	each server has a read and write socket end).
1252		1463
1253	I<create> is the time it takes to create a socketpair (which is	1464	I<create> is the time it takes to create a socket pair (which is
1254	nontrivial) and two watchers: an I/O watcher and a timeout watcher.	1465	nontrivial) and two watchers: an I/O watcher and a timeout watcher.
1255		1466
1256	I<request>, the most important value, is the time it takes to handle a	1467	I<request>, the most important value, is the time it takes to handle a
1257	single "request", that is, reading the token from the pipe and forwarding	1468	single "request", that is, reading the token from the pipe and forwarding
1258	it to another server. This includes deleting the old timeout and creating	1469	it to another server. This includes deleting the old timeout and creating
…		…
1331	speed most when you have lots of watchers, not when you only have a few of	1542	speed most when you have lots of watchers, not when you only have a few of
1332	them).	1543	them).
1333		1544
1334	EV is again fastest.	1545	EV is again fastest.
1335		1546
1336	Perl again comes second. It is noticably faster than the C-based event	1547	Perl again comes second. It is noticeably faster than the C-based event
1337	loops Event and Glib, although the difference is too small to really	1548	loops Event and Glib, although the difference is too small to really
1338	matter.	1549	matter.
1339		1550
1340	POE also performs much better in this case, but is is still far behind the	1551	POE also performs much better in this case, but is is still far behind the
1341	others.	1552	others.
…		…
1374		1585
1375	BEGIN { delete $ENV{PERL_ANYEVENT_MODEL} }	1586	BEGIN { delete $ENV{PERL_ANYEVENT_MODEL} }
1376		1587
1377	use AnyEvent;	1588	use AnyEvent;
1378		1589
		1590	Similar considerations apply to $ENV{PERL_ANYEVENT_VERBOSE}, as that can
		1591	be used to probe what backend is used and gain other information (which is
		1592	probably even less useful to an attacker than PERL_ANYEVENT_MODEL).
		1593
1379		1594
1380	=head1 SEE ALSO	1595	=head1 SEE ALSO
1381		1596
1382	Event modules: L<Coro::EV>, L<EV>, L<EV::Glib>, L<Glib::EV>,	1597	Utility functions: L<AnyEvent::Util>.
1383	L<Coro::Event>, L<Event>, L<Glib::Event>, L<Glib>, L<Coro>, L<Tk>,	1598
		1599	Event modules: L<EV>, L<EV::Glib>, L<Glib::EV>, L<Event>, L<Glib::Event>,
1384	L<Event::Lib>, L<Qt>, L<POE>.	1600	L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>.
1385		1601
1386	Implementations: L<AnyEvent::Impl::CoroEV>, L<AnyEvent::Impl::EV>,	1602	Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>,
1387	L<AnyEvent::Impl::CoroEvent>, L<AnyEvent::Impl::Event>, L<AnyEvent::Impl::Glib>,	1603	L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>,
1388	L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>, L<AnyEvent::Impl::EventLib>,	1604	L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>,
1389	L<AnyEvent::Impl::Qt>, L<AnyEvent::Impl::POE>.	1605	L<AnyEvent::Impl::POE>.
1390		1606
		1607	Non-blocking file handles, sockets, TCP clients and
		1608	servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>.
		1609
		1610	Asynchronous DNS: L<AnyEvent::DNS>.
		1611
		1612	Coroutine support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>, L<Coro::Event>,
		1613
1391	Nontrivial usage examples: L<Net::FCP>, L<Net::XMPP2>.	1614	Nontrivial usage examples: L<Net::FCP>, L<Net::XMPP2>, L<AnyEvent::DNS>.
1392		1615
1393		1616
1394	=head1 AUTHOR	1617	=head1 AUTHOR
1395		1618
1396	Marc Lehmann <schmorp@schmorp.de>	1619	Marc Lehmann <schmorp@schmorp.de>

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Comparing AnyEvent/lib/AnyEvent.pm (file contents): Revision 1.105 by root, Thu May 1 12:35:54 2008 UTC vs. Revision 1.142 by root, Tue May 27 02:34:30 2008 UTC

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Comparing AnyEvent/lib/AnyEvent.pm (file contents):
Revision 1.105 by root, Thu May 1 12:35:54 2008 UTC vs.
Revision 1.142 by root, Tue May 27 02:34:30 2008 UTC