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

Comparing AnyEvent/lib/AnyEvent.pm (file contents):
Revision 1.104 by root, Wed Apr 30 11:40:22 2008 UTC vs.
Revision 1.146 by root, Fri May 30 21:38:46 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).
…		…
227	timers.	233	timers.
228		234
229	AnyEvent always prefers relative timers, if available, matching the	235	AnyEvent always prefers relative timers, if available, matching the
230	AnyEvent API.	236	AnyEvent API.
231		237
		238	AnyEvent has two additional methods that return the "current time":
		239
		240	=over 4
		241
		242	=item AnyEvent->time
		243
		244	This returns the "current wallclock time" as a fractional number of
		245	seconds since the Epoch (the same thing as C<time> or C<Time::HiRes::time>
		246	return, and the result is guaranteed to be compatible with those).
		247
		248	It progresses independently of any event loop processing, i.e. each call
		249	will check the system clock, which usually gets updated frequently.
		250
		251	=item AnyEvent->now
		252
		253	This also returns the "current wallclock time", but unlike C<time>, above,
		254	this value might change only once per event loop iteration, depending on
		255	the event loop (most return the same time as C<time>, above). This is the
		256	time that AnyEvent's timers get scheduled against.
		257
		258	I<In almost all cases (in all cases if you don't care), this is the
		259	function to call when you want to know the current time.>
		260
		261	This function is also often faster then C<< AnyEvent->time >>, and
		262	thus the preferred method if you want some timestamp (for example,
		263	L<AnyEvent::Handle> uses this to update it's activity timeouts).
		264
		265	The rest of this section is only of relevance if you try to be very exact
		266	with your timing, you can skip it without bad conscience.
		267
		268	For a practical example of when these times differ, consider L<Event::Lib>
		269	and L<EV> and the following set-up:
		270
		271	The event loop is running and has just invoked one of your callback at
		272	time=500 (assume no other callbacks delay processing). In your callback,
		273	you wait a second by executing C<sleep 1> (blocking the process for a
		274	second) and then (at time=501) you create a relative timer that fires
		275	after three seconds.
		276
		277	With L<Event::Lib>, C<< AnyEvent->time >> and C<< AnyEvent->now >> will
		278	both return C<501>, because that is the current time, and the timer will
		279	be scheduled to fire at time=504 (C<501> + C<3>).
		280
		281	With L<EV>, C<< AnyEvent->time >> returns C<501> (as that is the current
		282	time), but C<< AnyEvent->now >> returns C<500>, as that is the time the
		283	last event processing phase started. With L<EV>, your timer gets scheduled
		284	to run at time=503 (C<500> + C<3>).
		285
		286	In one sense, L<Event::Lib> is more exact, as it uses the current time
		287	regardless of any delays introduced by event processing. However, most
		288	callbacks do not expect large delays in processing, so this causes a
		289	higher drift (and a lot more system calls to get the current time).
		290
		291	In another sense, L<EV> is more exact, as your timer will be scheduled at
		292	the same time, regardless of how long event processing actually took.
		293
		294	In either case, if you care (and in most cases, you don't), then you
		295	can get whatever behaviour you want with any event loop, by taking the
		296	difference between C<< AnyEvent->time >> and C<< AnyEvent->now >> into
		297	account.
		298
		299	=back
		300
232	=head2 SIGNAL WATCHERS	301	=head2 SIGNAL WATCHERS
233		302
234	You can watch for signals using a signal watcher, C<signal> is the signal	303	You can watch for signals using a signal watcher, C<signal> is the signal
235	I<name> without any C<SIG> prefix, C<cb> is the Perl callback to	304	I<name> without any C<SIG> prefix, C<cb> is the Perl callback to
236	be invoked whenever a signal occurs.	305	be invoked whenever a signal occurs.
237		306
238	Although the callback might get passed parameters, their value and	307	Although the callback might get passed parameters, their value and
239	presence is undefined and you cannot rely on them. Portable AnyEvent	308	presence is undefined and you cannot rely on them. Portable AnyEvent
240	callbacks cannot use arguments passed to signal watcher callbacks.	309	callbacks cannot use arguments passed to signal watcher callbacks.
241		310
242	Multiple signal occurances can be clumped together into one callback	311	Multiple signal occurrences can be clumped together into one callback
243	invocation, and callback invocation will be synchronous. synchronous means	312	invocation, and callback invocation will be synchronous. Synchronous means
244	that it might take a while until the signal gets handled by the process,	313	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.	314	but it is guaranteed not to interrupt any other callbacks.
246		315
247	The main advantage of using these watchers is that you can share a signal	316	The main advantage of using these watchers is that you can share a signal
248	between multiple watchers.	317	between multiple watchers.
249		318
250	This watcher might use C<%SIG>, so programs overwriting those signals	319	This watcher might use C<%SIG>, so programs overwriting those signals
…		…
279		348
280	Example: fork a process and wait for it	349	Example: fork a process and wait for it
281		350
282	my $done = AnyEvent->condvar;	351	my $done = AnyEvent->condvar;
283		352
284	AnyEvent::detect; # force event module to be initialised
285
286	my $pid = fork or exit 5;	353	my $pid = fork or exit 5;
287		354
288	my $w = AnyEvent->child (	355	my $w = AnyEvent->child (
289	pid => $pid,	356	pid => $pid,
290	cb => sub {	357	cb => sub {
291	my ($pid, $status) = @_;	358	my ($pid, $status) = @_;
292	warn "pid $pid exited with status $status";	359	warn "pid $pid exited with status $status";
293	$done->broadcast;	360	$done->send;
294	},	361	},
295	);	362	);
296		363
297	# do something else, then wait for process exit	364	# do something else, then wait for process exit
298	$done->wait;	365	$done->recv;
299		366
300	=head2 CONDITION VARIABLES	367	=head2 CONDITION VARIABLES
301		368
		369	If you are familiar with some event loops you will know that all of them
		370	require you to run some blocking "loop", "run" or similar function that
		371	will actively watch for new events and call your callbacks.
		372
		373	AnyEvent is different, it expects somebody else to run the event loop and
		374	will only block when necessary (usually when told by the user).
		375
		376	The instrument to do that is called a "condition variable", so called
		377	because they represent a condition that must become true.
		378
302	Condition variables can be created by calling the C<< AnyEvent->condvar >>	379	Condition variables can be created by calling the C<< AnyEvent->condvar
303	method without any arguments.	380	>> method, usually without arguments. The only argument pair allowed is
		381	C<cb>, which specifies a callback to be called when the condition variable
		382	becomes true.
304		383
305	A condition variable waits for a condition - precisely that the C<<	384	After creation, the condition variable is "false" until it becomes "true"
306	->broadcast >> method has been called.	385	by calling the C<send> method (or calling the condition variable as if it
		386	were a callback, read about the caveats in the description for the C<<
		387	->send >> method).
307		388
308	They are very useful to signal that a condition has been fulfilled, for	389	Condition variables are similar to callbacks, except that you can
		390	optionally wait for them. They can also be called merge points - points
		391	in time where multiple outstanding events have been processed. And yet
		392	another way to call them is transactions - each condition variable can be
		393	used to represent a transaction, which finishes at some point and delivers
		394	a result.
		395
		396	Condition variables are very useful to signal that something has finished,
309	example, if you write a module that does asynchronous http requests,	397	for example, if you write a module that does asynchronous http requests,
310	then a condition variable would be the ideal candidate to signal the	398	then a condition variable would be the ideal candidate to signal the
311	availability of results.	399	availability of results. The user can either act when the callback is
		400	called or can synchronously C<< ->recv >> for the results.
312		401
313	You can also use condition variables to block your main program until	402	You can also use them to simulate traditional event loops - for example,
314	an event occurs - for example, you could C<< ->wait >> in your main	403	you can block your main program until an event occurs - for example, you
315	program until the user clicks the Quit button in your app, which would C<<	404	could C<< ->recv >> in your main program until the user clicks the Quit
316	->broadcast >> the "quit" event.	405	button of your app, which would C<< ->send >> the "quit" event.
317		406
318	Note that condition variables recurse into the event loop - if you have	407	Note that condition variables recurse into the event loop - if you have
319	two pirces of code that call C<< ->wait >> in a round-robbin fashion, you	408	two pieces of code that call C<< ->recv >> in a round-robin fashion, you
320	lose. Therefore, condition variables are good to export to your caller, but	409	lose. Therefore, condition variables are good to export to your caller, but
321	you should avoid making a blocking wait yourself, at least in callbacks,	410	you should avoid making a blocking wait yourself, at least in callbacks,
322	as this asks for trouble.	411	as this asks for trouble.
323		412
324	This object has two methods:	413	Condition variables are represented by hash refs in perl, and the keys
		414	used by AnyEvent itself are all named C<_ae_XXX> to make subclassing
		415	easy (it is often useful to build your own transaction class on top of
		416	AnyEvent). To subclass, use C<AnyEvent::CondVar> as base class and call
		417	it's C<new> method in your own C<new> method.
		418
		419	There are two "sides" to a condition variable - the "producer side" which
		420	eventually calls C<< -> send >>, and the "consumer side", which waits
		421	for the send to occur.
		422
		423	Example: wait for a timer.
		424
		425	# wait till the result is ready
		426	my $result_ready = AnyEvent->condvar;
		427
		428	# do something such as adding a timer
		429	# or socket watcher the calls $result_ready->send
		430	# when the "result" is ready.
		431	# in this case, we simply use a timer:
		432	my $w = AnyEvent->timer (
		433	after => 1,
		434	cb => sub { $result_ready->send },
		435	);
		436
		437	# this "blocks" (while handling events) till the callback
		438	# calls send
		439	$result_ready->recv;
		440
		441	Example: wait for a timer, but take advantage of the fact that
		442	condition variables are also code references.
		443
		444	my $done = AnyEvent->condvar;
		445	my $delay = AnyEvent->timer (after => 5, cb => $done);
		446	$done->recv;
		447
		448	=head3 METHODS FOR PRODUCERS
		449
		450	These methods should only be used by the producing side, i.e. the
		451	code/module that eventually sends the signal. Note that it is also
		452	the producer side which creates the condvar in most cases, but it isn't
		453	uncommon for the consumer to create it as well.
325		454
326	=over 4	455	=over 4
327		456
		457	=item $cv->send (...)
		458
		459	Flag the condition as ready - a running C<< ->recv >> and all further
		460	calls to C<recv> will (eventually) return after this method has been
		461	called. If nobody is waiting the send will be remembered.
		462
		463	If a callback has been set on the condition variable, it is called
		464	immediately from within send.
		465
		466	Any arguments passed to the C<send> call will be returned by all
		467	future C<< ->recv >> calls.
		468
		469	Condition variables are overloaded so one can call them directly
		470	(as a code reference). Calling them directly is the same as calling
		471	C<send>. Note, however, that many C-based event loops do not handle
		472	overloading, so as tempting as it may be, passing a condition variable
		473	instead of a callback does not work. Both the pure perl and EV loops
		474	support overloading, however, as well as all functions that use perl to
		475	invoke a callback (as in L<AnyEvent::Socket> and L<AnyEvent::DNS> for
		476	example).
		477
		478	=item $cv->croak ($error)
		479
		480	Similar to send, but causes all call's to C<< ->recv >> to invoke
		481	C<Carp::croak> with the given error message/object/scalar.
		482
		483	This can be used to signal any errors to the condition variable
		484	user/consumer.
		485
		486	=item $cv->begin ([group callback])
		487
328	=item $cv->wait	488	=item $cv->end
329		489
330	Wait (blocking if necessary) until the C<< ->broadcast >> method has been	490	These two methods are EXPERIMENTAL and MIGHT CHANGE.
		491
		492	These two methods can be used to combine many transactions/events into
		493	one. For example, a function that pings many hosts in parallel might want
		494	to use a condition variable for the whole process.
		495
		496	Every call to C<< ->begin >> will increment a counter, and every call to
		497	C<< ->end >> will decrement it. If the counter reaches C<0> in C<< ->end
		498	>>, the (last) callback passed to C<begin> will be executed. That callback
		499	is I<supposed> to call C<< ->send >>, but that is not required. If no
		500	callback was set, C<send> will be called without any arguments.
		501
		502	Let's clarify this with the ping example:
		503
		504	my $cv = AnyEvent->condvar;
		505
		506	my %result;
		507	$cv->begin (sub { $cv->send (\%result) });
		508
		509	for my $host (@list_of_hosts) {
		510	$cv->begin;
		511	ping_host_then_call_callback $host, sub {
		512	$result{$host} = ...;
		513	$cv->end;
		514	};
		515	}
		516
		517	$cv->end;
		518
		519	This code fragment supposedly pings a number of hosts and calls
		520	C<send> after results for all then have have been gathered - in any
		521	order. To achieve this, the code issues a call to C<begin> when it starts
		522	each ping request and calls C<end> when it has received some result for
		523	it. Since C<begin> and C<end> only maintain a counter, the order in which
		524	results arrive is not relevant.
		525
		526	There is an additional bracketing call to C<begin> and C<end> outside the
		527	loop, which serves two important purposes: first, it sets the callback
		528	to be called once the counter reaches C<0>, and second, it ensures that
		529	C<send> is called even when C<no> hosts are being pinged (the loop
		530	doesn't execute once).
		531
		532	This is the general pattern when you "fan out" into multiple subrequests:
		533	use an outer C<begin>/C<end> pair to set the callback and ensure C<end>
		534	is called at least once, and then, for each subrequest you start, call
		535	C<begin> and for each subrequest you finish, call C<end>.
		536
		537	=back
		538
		539	=head3 METHODS FOR CONSUMERS
		540
		541	These methods should only be used by the consuming side, i.e. the
		542	code awaits the condition.
		543
		544	=over 4
		545
		546	=item $cv->recv
		547
		548	Wait (blocking if necessary) until the C<< ->send >> or C<< ->croak
331	called on c<$cv>, while servicing other watchers normally.	549	>> methods have been called on c<$cv>, while servicing other watchers
		550	normally.
332		551
333	You can only wait once on a condition - additional calls will return	552	You can only wait once on a condition - additional calls are valid but
334	immediately.	553	will return immediately.
		554
		555	If an error condition has been set by calling C<< ->croak >>, then this
		556	function will call C<croak>.
		557
		558	In list context, all parameters passed to C<send> will be returned,
		559	in scalar context only the first one will be returned.
335		560
336	Not all event models support a blocking wait - some die in that case	561	Not all event models support a blocking wait - some die in that case
337	(programs might want to do that to stay interactive), so I<if you are	562	(programs might want to do that to stay interactive), so I<if you are
338	using this from a module, never require a blocking wait>, but let the	563	using this from a module, never require a blocking wait>, but let the
339	caller decide whether the call will block or not (for example, by coupling	564	caller decide whether the call will block or not (for example, by coupling
340	condition variables with some kind of request results and supporting	565	condition variables with some kind of request results and supporting
341	callbacks so the caller knows that getting the result will not block,	566	callbacks so the caller knows that getting the result will not block,
342	while still suppporting blocking waits if the caller so desires).	567	while still supporting blocking waits if the caller so desires).
343		568
344	Another reason I<never> to C<< ->wait >> in a module is that you cannot	569	Another reason I<never> to C<< ->recv >> in a module is that you cannot
345	sensibly have two C<< ->wait >>'s in parallel, as that would require	570	sensibly have two C<< ->recv >>'s in parallel, as that would require
346	multiple interpreters or coroutines/threads, none of which C<AnyEvent>	571	multiple interpreters or coroutines/threads, none of which C<AnyEvent>
347	can supply (the coroutine-aware backends L<AnyEvent::Impl::CoroEV> and	572	can supply.
348	L<AnyEvent::Impl::CoroEvent> explicitly support concurrent C<< ->wait >>'s
349	from different coroutines, however).
350		573
351	=item $cv->broadcast	574	The L<Coro> module, however, I<can> and I<does> supply coroutines and, in
		575	fact, L<Coro::AnyEvent> replaces AnyEvent's condvars by coroutine-safe
		576	versions and also integrates coroutines into AnyEvent, making blocking
		577	C<< ->recv >> calls perfectly safe as long as they are done from another
		578	coroutine (one that doesn't run the event loop).
352		579
353	Flag the condition as ready - a running C<< ->wait >> and all further	580	You can ensure that C<< -recv >> never blocks by setting a callback and
354	calls to C<wait> will (eventually) return after this method has been	581	only calling C<< ->recv >> from within that callback (or at a later
355	called. If nobody is waiting the broadcast will be remembered..	582	time). This will work even when the event loop does not support blocking
		583	waits otherwise.
		584
		585	=item $bool = $cv->ready
		586
		587	Returns true when the condition is "true", i.e. whether C<send> or
		588	C<croak> have been called.
		589
		590	=item $cb = $cv->cb ([new callback])
		591
		592	This is a mutator function that returns the callback set and optionally
		593	replaces it before doing so.
		594
		595	The callback will be called when the condition becomes "true", i.e. when
		596	C<send> or C<croak> are called. Calling C<recv> inside the callback
		597	or at any later time is guaranteed not to block.
356		598
357	=back	599	=back
358
359	Example:
360
361	# wait till the result is ready
362	my $result_ready = AnyEvent->condvar;
363
364	# do something such as adding a timer
365	# or socket watcher the calls $result_ready->broadcast
366	# when the "result" is ready.
367	# in this case, we simply use a timer:
368	my $w = AnyEvent->timer (
369	after => 1,
370	cb => sub { $result_ready->broadcast },
371	);
372
373	# this "blocks" (while handling events) till the watcher
374	# calls broadcast
375	$result_ready->wait;
376		600
377	=head1 GLOBAL VARIABLES AND FUNCTIONS	601	=head1 GLOBAL VARIABLES AND FUNCTIONS
378		602
379	=over 4	603	=over 4
380		604
…		…
386	C<AnyEvent::Impl:xxx> modules, but can be any other class in the case	610	C<AnyEvent::Impl:xxx> modules, but can be any other class in the case
387	AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode>).	611	AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode>).
388		612
389	The known classes so far are:	613	The known classes so far are:
390		614
391	AnyEvent::Impl::CoroEV based on Coro::EV, best choice.
392	AnyEvent::Impl::CoroEvent based on Coro::Event, second best choice.
393	AnyEvent::Impl::EV based on EV (an interface to libev, best choice).	615	AnyEvent::Impl::EV based on EV (an interface to libev, best choice).
394	AnyEvent::Impl::Event based on Event, second best choice.	616	AnyEvent::Impl::Event based on Event, second best choice.
395	AnyEvent::Impl::Perl pure-perl implementation, fast and portable.	617	AnyEvent::Impl::Perl pure-perl implementation, fast and portable.
396	AnyEvent::Impl::Glib based on Glib, third-best choice.	618	AnyEvent::Impl::Glib based on Glib, third-best choice.
397	AnyEvent::Impl::Tk based on Tk, very bad choice.	619	AnyEvent::Impl::Tk based on Tk, very bad choice.
…		…
414	Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model	636	Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model
415	if necessary. You should only call this function right before you would	637	if necessary. You should only call this function right before you would
416	have created an AnyEvent watcher anyway, that is, as late as possible at	638	have created an AnyEvent watcher anyway, that is, as late as possible at
417	runtime.	639	runtime.
418		640
		641	=item $guard = AnyEvent::post_detect { BLOCK }
		642
		643	Arranges for the code block to be executed as soon as the event model is
		644	autodetected (or immediately if this has already happened).
		645
		646	If called in scalar or list context, then it creates and returns an object
		647	that automatically removes the callback again when it is destroyed. See
		648	L<Coro::BDB> for a case where this is useful.
		649
		650	=item @AnyEvent::post_detect
		651
		652	If there are any code references in this array (you can C<push> to it
		653	before or after loading AnyEvent), then they will called directly after
		654	the event loop has been chosen.
		655
		656	You should check C<$AnyEvent::MODEL> before adding to this array, though:
		657	if it contains a true value then the event loop has already been detected,
		658	and the array will be ignored.
		659
		660	Best use C<AnyEvent::post_detect { BLOCK }> instead.
		661
419	=back	662	=back
420		663
421	=head1 WHAT TO DO IN A MODULE	664	=head1 WHAT TO DO IN A MODULE
422		665
423	As a module author, you should C<use AnyEvent> and call AnyEvent methods	666	As a module author, you should C<use AnyEvent> and call AnyEvent methods
…		…
426	Be careful when you create watchers in the module body - AnyEvent will	669	Be careful when you create watchers in the module body - AnyEvent will
427	decide which event module to use as soon as the first method is called, so	670	decide which event module to use as soon as the first method is called, so
428	by calling AnyEvent in your module body you force the user of your module	671	by calling AnyEvent in your module body you force the user of your module
429	to load the event module first.	672	to load the event module first.
430		673
431	Never call C<< ->wait >> on a condition variable unless you I<know> that	674	Never call C<< ->recv >> on a condition variable unless you I<know> that
432	the C<< ->broadcast >> method has been called on it already. This is	675	the C<< ->send >> method has been called on it already. This is
433	because it will stall the whole program, and the whole point of using	676	because it will stall the whole program, and the whole point of using
434	events is to stay interactive.	677	events is to stay interactive.
435		678
436	It is fine, however, to call C<< ->wait >> when the user of your module	679	It is fine, however, to call C<< ->recv >> when the user of your module
437	requests it (i.e. if you create a http request object ad have a method	680	requests it (i.e. if you create a http request object ad have a method
438	called C<results> that returns the results, it should call C<< ->wait >>	681	called C<results> that returns the results, it should call C<< ->recv >>
439	freely, as the user of your module knows what she is doing. always).	682	freely, as the user of your module knows what she is doing. always).
440		683
441	=head1 WHAT TO DO IN THE MAIN PROGRAM	684	=head1 WHAT TO DO IN THE MAIN PROGRAM
442		685
443	There will always be a single main program - the only place that should	686	There will always be a single main program - the only place that should
…		…
445		688
446	If it doesn't care, it can just "use AnyEvent" and use it itself, or not	689	If it doesn't care, it can just "use AnyEvent" and use it itself, or not
447	do anything special (it does not need to be event-based) and let AnyEvent	690	do anything special (it does not need to be event-based) and let AnyEvent
448	decide which implementation to chose if some module relies on it.	691	decide which implementation to chose if some module relies on it.
449		692
450	If the main program relies on a specific event model. For example, in	693	If the main program relies on a specific event model - for example, in
451	Gtk2 programs you have to rely on the Glib module. You should load the	694	Gtk2 programs you have to rely on the Glib module - you should load the
452	event module before loading AnyEvent or any module that uses it: generally	695	event module before loading AnyEvent or any module that uses it: generally
453	speaking, you should load it as early as possible. The reason is that	696	speaking, you should load it as early as possible. The reason is that
454	modules might create watchers when they are loaded, and AnyEvent will	697	modules might create watchers when they are loaded, and AnyEvent will
455	decide on the event model to use as soon as it creates watchers, and it	698	decide on the event model to use as soon as it creates watchers, and it
456	might chose the wrong one unless you load the correct one yourself.	699	might chose the wrong one unless you load the correct one yourself.
457		700
458	You can chose to use a rather inefficient pure-perl implementation by	701	You can chose to use a pure-perl implementation by loading the
459	loading the C<AnyEvent::Impl::Perl> module, which gives you similar	702	C<AnyEvent::Impl::Perl> module, which gives you similar behaviour
460	behaviour everywhere, but letting AnyEvent chose is generally better.	703	everywhere, but letting AnyEvent chose the model is generally better.
		704
		705	=head2 MAINLOOP EMULATION
		706
		707	Sometimes (often for short test scripts, or even standalone programs who
		708	only want to use AnyEvent), you do not want to run a specific event loop.
		709
		710	In that case, you can use a condition variable like this:
		711
		712	AnyEvent->condvar->recv;
		713
		714	This has the effect of entering the event loop and looping forever.
		715
		716	Note that usually your program has some exit condition, in which case
		717	it is better to use the "traditional" approach of storing a condition
		718	variable somewhere, waiting for it, and sending it when the program should
		719	exit cleanly.
		720
461		721
462	=head1 OTHER MODULES	722	=head1 OTHER MODULES
463		723
464	The following is a non-exhaustive list of additional modules that use	724	The following is a non-exhaustive list of additional modules that use
465	AnyEvent and can therefore be mixed easily with other AnyEvent modules	725	AnyEvent and can therefore be mixed easily with other AnyEvent modules
…		…
477		737
478	Provide read and write buffers and manages watchers for reads and writes.	738	Provide read and write buffers and manages watchers for reads and writes.
479		739
480	=item L<AnyEvent::Socket>	740	=item L<AnyEvent::Socket>
481		741
482	Provides a means to do non-blocking connects, accepts etc.	742	Provides various utility functions for (internet protocol) sockets,
		743	addresses and name resolution. Also functions to create non-blocking tcp
		744	connections or tcp servers, with IPv6 and SRV record support and more.
		745
		746	=item L<AnyEvent::DNS>
		747
		748	Provides rich asynchronous DNS resolver capabilities.
483		749
484	=item L<AnyEvent::HTTPD>	750	=item L<AnyEvent::HTTPD>
485		751
486	Provides a simple web application server framework.	752	Provides a simple web application server framework.
487
488	=item L<AnyEvent::DNS>
489
490	Provides asynchronous DNS resolver capabilities, beyond what
491	L<AnyEvent::Util> offers.
492		753
493	=item L<AnyEvent::FastPing>	754	=item L<AnyEvent::FastPing>
494		755
495	The fastest ping in the west.	756	The fastest ping in the west.
496		757
…		…
511		772
512	High level API for event-based execution flow control.	773	High level API for event-based execution flow control.
513		774
514	=item L<Coro>	775	=item L<Coro>
515		776
516	Has special support for AnyEvent.	777	Has special support for AnyEvent via L<Coro::AnyEvent>.
		778
		779	=item L<AnyEvent::AIO>, L<IO::AIO>
		780
		781	Truly asynchronous I/O, should be in the toolbox of every event
		782	programmer. AnyEvent::AIO transparently fuses IO::AIO and AnyEvent
		783	together.
		784
		785	=item L<AnyEvent::BDB>, L<BDB>
		786
		787	Truly asynchronous Berkeley DB access. AnyEvent::AIO transparently fuses
		788	IO::AIO and AnyEvent together.
517		789
518	=item L<IO::Lambda>	790	=item L<IO::Lambda>
519		791
520	The lambda approach to I/O - don't ask, look there. Can use AnyEvent.	792	The lambda approach to I/O - don't ask, look there. Can use AnyEvent.
521
522	=item L<IO::AIO>
523
524	Truly asynchronous I/O, should be in the toolbox of every event
525	programmer. Can be trivially made to use AnyEvent.
526
527	=item L<BDB>
528
529	Truly asynchronous Berkeley DB access. Can be trivially made to use
530	AnyEvent.
531		793
532	=back	794	=back
533		795
534	=cut	796	=cut
535		797
…		…
538	no warnings;	800	no warnings;
539	use strict;	801	use strict;
540		802
541	use Carp;	803	use Carp;
542		804
543	our $VERSION = '3.3';	805	our $VERSION = 4.1;
544	our $MODEL;	806	our $MODEL;
545		807
546	our $AUTOLOAD;	808	our $AUTOLOAD;
547	our @ISA;	809	our @ISA;
548		810
		811	our @REGISTRY;
		812
		813	our $WIN32;
		814
		815	BEGIN {
		816	my $win32 = ! ! ($^O =~ /mswin32/i);
		817	eval "sub WIN32(){ $win32 }";
		818	}
		819
549	our $verbose = $ENV{PERL_ANYEVENT_VERBOSE}*1;	820	our $verbose = $ENV{PERL_ANYEVENT_VERBOSE}*1;
550		821
551	our @REGISTRY;	822	our %PROTOCOL; # (ipv4\|ipv6) => (1\|2), higher numbers are preferred
		823
		824	{
		825	my $idx;
		826	$PROTOCOL{$_} = ++$idx
		827	for reverse split /\s,\s/,
		828	$ENV{PERL_ANYEVENT_PROTOCOLS} \|\| "ipv4,ipv6";
		829	}
552		830
553	my @models = (	831	my @models = (
554	[Coro::EV:: => AnyEvent::Impl::CoroEV::],
555	[Coro::Event:: => AnyEvent::Impl::CoroEvent::],
556	[EV:: => AnyEvent::Impl::EV::],	832	[EV:: => AnyEvent::Impl::EV::],
557	[Event:: => AnyEvent::Impl::Event::],	833	[Event:: => AnyEvent::Impl::Event::],
558	[Tk:: => AnyEvent::Impl::Tk::],
559	[Wx:: => AnyEvent::Impl::POE::],
560	[Prima:: => AnyEvent::Impl::POE::],
561	[AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl::],	834	[AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl::],
562	# everything below here will not be autoprobed as the pureperl backend should work everywhere	835	# everything below here will not be autoprobed
563	[Glib:: => AnyEvent::Impl::Glib::],	836	# as the pureperl backend should work everywhere
		837	# and is usually faster
		838	[Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles
		839	[Glib:: => AnyEvent::Impl::Glib::], # becomes extremely slow with many watchers
564	[Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy	840	[Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy
565	[Qt:: => AnyEvent::Impl::Qt::], # requires special main program	841	[Qt:: => AnyEvent::Impl::Qt::], # requires special main program
566	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza	842	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza
		843	[Wx:: => AnyEvent::Impl::POE::],
		844	[Prima:: => AnyEvent::Impl::POE::],
567	);	845	);
568		846
569	our %method = map +($_ => 1), qw(io timer signal child condvar broadcast wait one_event DESTROY);	847	our %method = map +($_ => 1), qw(io timer time now signal child condvar one_event DESTROY);
		848
		849	our @post_detect;
		850
		851	sub post_detect(&) {
		852	my ($cb) = @_;
		853
		854	if ($MODEL) {
		855	$cb->();
		856
		857	1
		858	} else {
		859	push @post_detect, $cb;
		860
		861	defined wantarray
		862	? bless \$cb, "AnyEvent::Util::PostDetect"
		863	: ()
		864	}
		865	}
		866
		867	sub AnyEvent::Util::PostDetect::DESTROY {
		868	@post_detect = grep $_ != ${$_[0]}, @post_detect;
		869	}
570		870
571	sub detect() {	871	sub detect() {
572	unless ($MODEL) {	872	unless ($MODEL) {
573	no strict 'refs';	873	no strict 'refs';
		874	local $SIG{__DIE__};
574		875
575	if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) {	876	if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) {
576	my $model = "AnyEvent::Impl::$1";	877	my $model = "AnyEvent::Impl::$1";
577	if (eval "require $model") {	878	if (eval "require $model") {
578	$MODEL = $model;	879	$MODEL = $model;
…		…
608	last;	909	last;
609	}	910	}
610	}	911	}
611		912
612	$MODEL	913	$MODEL
613	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.";	914	or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV, Event or Glib.";
614	}	915	}
615	}	916	}
616		917
617	unshift @ISA, $MODEL;	918	unshift @ISA, $MODEL;
618	push @{"$MODEL\::ISA"}, "AnyEvent::Base";	919	push @{"$MODEL\::ISA"}, "AnyEvent::Base";
		920
		921	(shift @post_detect)->() while @post_detect;
619	}	922	}
620		923
621	$MODEL	924	$MODEL
622	}	925	}
623		926
…		…
633	$class->$func (@_);	936	$class->$func (@_);
634	}	937	}
635		938
636	package AnyEvent::Base;	939	package AnyEvent::Base;
637		940
		941	# default implementation for now and time
		942
		943	use Time::HiRes ();
		944
		945	sub time { Time::HiRes::time }
		946	sub now { Time::HiRes::time }
		947
638	# default implementation for ->condvar, ->wait, ->broadcast	948	# default implementation for ->condvar
639		949
640	sub condvar {	950	sub condvar {
641	bless \my $flag, "AnyEvent::Base::CondVar"	951	bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, AnyEvent::CondVar::
642	}
643
644	sub AnyEvent::Base::CondVar::broadcast {
645	${$_[0]}++;
646	}
647
648	sub AnyEvent::Base::CondVar::wait {
649	AnyEvent->one_event while !${$_[0]};
650	}	952	}
651		953
652	# default implementation for ->signal	954	# default implementation for ->signal
653		955
654	our %SIG_CB;	956	our %SIG_CB;
…		…
707	or Carp::croak "required option 'pid' is missing";	1009	or Carp::croak "required option 'pid' is missing";
708		1010
709	$PID_CB{$pid}{$arg{cb}} = $arg{cb};	1011	$PID_CB{$pid}{$arg{cb}} = $arg{cb};
710		1012
711	unless ($WNOHANG) {	1013	unless ($WNOHANG) {
712	$WNOHANG = eval { require POSIX; &POSIX::WNOHANG } \|\| 1;	1014	$WNOHANG = eval { local $SIG{__DIE__}; require POSIX; &POSIX::WNOHANG } \|\| 1;
713	}	1015	}
714		1016
715	unless ($CHLD_W) {	1017	unless ($CHLD_W) {
716	$CHLD_W = AnyEvent->signal (signal => 'CHLD', cb => \&_sigchld);	1018	$CHLD_W = AnyEvent->signal (signal => 'CHLD', cb => \&_sigchld);
717	# child could be a zombie already, so make at least one round	1019	# child could be a zombie already, so make at least one round
…		…
727	delete $PID_CB{$pid}{$cb};	1029	delete $PID_CB{$pid}{$cb};
728	delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };	1030	delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };
729		1031
730	undef $CHLD_W unless keys %PID_CB;	1032	undef $CHLD_W unless keys %PID_CB;
731	}	1033	}
		1034
		1035	package AnyEvent::CondVar;
		1036
		1037	our @ISA = AnyEvent::CondVar::Base::;
		1038
		1039	package AnyEvent::CondVar::Base;
		1040
		1041	use overload
		1042	'&{}' => sub { my $self = shift; sub { $self->send (@_) } },
		1043	fallback => 1;
		1044
		1045	sub _send {
		1046	# nop
		1047	}
		1048
		1049	sub send {
		1050	my $cv = shift;
		1051	$cv->{_ae_sent} = [@_];
		1052	(delete $cv->{_ae_cb})->($cv) if $cv->{_ae_cb};
		1053	$cv->_send;
		1054	}
		1055
		1056	sub croak {
		1057	$_[0]{_ae_croak} = $_[1];
		1058	$_[0]->send;
		1059	}
		1060
		1061	sub ready {
		1062	$_[0]{_ae_sent}
		1063	}
		1064
		1065	sub _wait {
		1066	AnyEvent->one_event while !$_[0]{_ae_sent};
		1067	}
		1068
		1069	sub recv {
		1070	$_[0]->_wait;
		1071
		1072	Carp::croak $_[0]{_ae_croak} if $_[0]{_ae_croak};
		1073	wantarray ? @{ $_[0]{_ae_sent} } : $_[0]{_ae_sent}[0]
		1074	}
		1075
		1076	sub cb {
		1077	$_[0]{_ae_cb} = $_[1] if @_ > 1;
		1078	$_[0]{_ae_cb}
		1079	}
		1080
		1081	sub begin {
		1082	++$_[0]{_ae_counter};
		1083	$_[0]{_ae_end_cb} = $_[1] if @_ > 1;
		1084	}
		1085
		1086	sub end {
		1087	return if --$_[0]{_ae_counter};
		1088	&{ $_[0]{_ae_end_cb} \|\| sub { $_[0]->send } };
		1089	}
		1090
		1091	# undocumented/compatibility with pre-3.4
		1092	*broadcast = \&send;
		1093	*wait = \&_wait;
732		1094
733	=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE	1095	=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE
734		1096
735	This is an advanced topic that you do not normally need to use AnyEvent in	1097	This is an advanced topic that you do not normally need to use AnyEvent in
736	a module. This section is only of use to event loop authors who want to	1098	a module. This section is only of use to event loop authors who want to
…		…
793	model it chooses.	1155	model it chooses.
794		1156
795	=item C<PERL_ANYEVENT_MODEL>	1157	=item C<PERL_ANYEVENT_MODEL>
796		1158
797	This can be used to specify the event model to be used by AnyEvent, before	1159	This can be used to specify the event model to be used by AnyEvent, before
798	autodetection and -probing kicks in. It must be a string consisting	1160	auto detection and -probing kicks in. It must be a string consisting
799	entirely of ASCII letters. The string C<AnyEvent::Impl::> gets prepended	1161	entirely of ASCII letters. The string C<AnyEvent::Impl::> gets prepended
800	and the resulting module name is loaded and if the load was successful,	1162	and the resulting module name is loaded and if the load was successful,
801	used as event model. If it fails to load AnyEvent will proceed with	1163	used as event model. If it fails to load AnyEvent will proceed with
802	autodetection and -probing.	1164	auto detection and -probing.
803		1165
804	This functionality might change in future versions.	1166	This functionality might change in future versions.
805		1167
806	For example, to force the pure perl model (L<AnyEvent::Impl::Perl>) you	1168	For example, to force the pure perl model (L<AnyEvent::Impl::Perl>) you
807	could start your program like this:	1169	could start your program like this:
808		1170
809	PERL_ANYEVENT_MODEL=Perl perl ...	1171	PERL_ANYEVENT_MODEL=Perl perl ...
		1172
		1173	=item C<PERL_ANYEVENT_PROTOCOLS>
		1174
		1175	Used by both L<AnyEvent::DNS> and L<AnyEvent::Socket> to determine preferences
		1176	for IPv4 or IPv6. The default is unspecified (and might change, or be the result
		1177	of auto probing).
		1178
		1179	Must be set to a comma-separated list of protocols or address families,
		1180	current supported: C<ipv4> and C<ipv6>. Only protocols mentioned will be
		1181	used, and preference will be given to protocols mentioned earlier in the
		1182	list.
		1183
		1184	This variable can effectively be used for denial-of-service attacks
		1185	against local programs (e.g. when setuid), although the impact is likely
		1186	small, as the program has to handle connection errors already-
		1187
		1188	Examples: C<PERL_ANYEVENT_PROTOCOLS=ipv4,ipv6> - prefer IPv4 over IPv6,
		1189	but support both and try to use both. C<PERL_ANYEVENT_PROTOCOLS=ipv4>
		1190	- only support IPv4, never try to resolve or contact IPv6
		1191	addresses. C<PERL_ANYEVENT_PROTOCOLS=ipv6,ipv4> support either IPv4 or
		1192	IPv6, but prefer IPv6 over IPv4.
		1193
		1194	=item C<PERL_ANYEVENT_EDNS0>
		1195
		1196	Used by L<AnyEvent::DNS> to decide whether to use the EDNS0 extension
		1197	for DNS. This extension is generally useful to reduce DNS traffic, but
		1198	some (broken) firewalls drop such DNS packets, which is why it is off by
		1199	default.
		1200
		1201	Setting this variable to C<1> will cause L<AnyEvent::DNS> to announce
		1202	EDNS0 in its DNS requests.
		1203
		1204	=item C<PERL_ANYEVENT_MAX_FORKS>
		1205
		1206	The maximum number of child processes that C<AnyEvent::Util::fork_call>
		1207	will create in parallel.
810		1208
811	=back	1209	=back
812		1210
813	=head1 EXAMPLE PROGRAM	1211	=head1 EXAMPLE PROGRAM
814		1212
…		…
825	poll => 'r',	1223	poll => 'r',
826	cb => sub {	1224	cb => sub {
827	warn "io event <$_[0]>\n"; # will always output <r>	1225	warn "io event <$_[0]>\n"; # will always output <r>
828	chomp (my $input = <STDIN>); # read a line	1226	chomp (my $input = <STDIN>); # read a line
829	warn "read: $input\n"; # output what has been read	1227	warn "read: $input\n"; # output what has been read
830	$cv->broadcast if $input =~ /^q/i; # quit program if /^q/i	1228	$cv->send if $input =~ /^q/i; # quit program if /^q/i
831	},	1229	},
832	);	1230	);
833		1231
834	my $time_watcher; # can only be used once	1232	my $time_watcher; # can only be used once
835		1233
…		…
840	});	1238	});
841	}	1239	}
842		1240
843	new_timer; # create first timer	1241	new_timer; # create first timer
844		1242
845	$cv->wait; # wait until user enters /^q/i	1243	$cv->recv; # wait until user enters /^q/i
846		1244
847	=head1 REAL-WORLD EXAMPLE	1245	=head1 REAL-WORLD EXAMPLE
848		1246
849	Consider the L<Net::FCP> module. It features (among others) the following	1247	Consider the L<Net::FCP> module. It features (among others) the following
850	API calls, which are to freenet what HTTP GET requests are to http:	1248	API calls, which are to freenet what HTTP GET requests are to http:
…		…
900	syswrite $txn->{fh}, $txn->{request}	1298	syswrite $txn->{fh}, $txn->{request}
901	or die "connection or write error";	1299	or die "connection or write error";
902	$txn->{w} = AnyEvent->io (fh => $txn->{fh}, poll => 'r', cb => sub { $txn->fh_ready_r });	1300	$txn->{w} = AnyEvent->io (fh => $txn->{fh}, poll => 'r', cb => sub { $txn->fh_ready_r });
903		1301
904	Again, C<fh_ready_r> waits till all data has arrived, and then stores the	1302	Again, C<fh_ready_r> waits till all data has arrived, and then stores the
905	result and signals any possible waiters that the request ahs finished:	1303	result and signals any possible waiters that the request has finished:
906		1304
907	sysread $txn->{fh}, $txn->{buf}, length $txn->{$buf};	1305	sysread $txn->{fh}, $txn->{buf}, length $txn->{$buf};
908		1306
909	if (end-of-file or data complete) {	1307	if (end-of-file or data complete) {
910	$txn->{result} = $txn->{buf};	1308	$txn->{result} = $txn->{buf};
911	$txn->{finished}->broadcast;	1309	$txn->{finished}->send;
912	$txb->{cb}->($txn) of $txn->{cb}; # also call callback	1310	$txb->{cb}->($txn) of $txn->{cb}; # also call callback
913	}	1311	}
914		1312
915	The C<result> method, finally, just waits for the finished signal (if the	1313	The C<result> method, finally, just waits for the finished signal (if the
916	request was already finished, it doesn't wait, of course, and returns the	1314	request was already finished, it doesn't wait, of course, and returns the
917	data:	1315	data:
918		1316
919	$txn->{finished}->wait;	1317	$txn->{finished}->recv;
920	return $txn->{result};	1318	return $txn->{result};
921		1319
922	The actual code goes further and collects all errors (C<die>s, exceptions)	1320	The actual code goes further and collects all errors (C<die>s, exceptions)
923	that occured during request processing. The C<result> method detects	1321	that occurred during request processing. The C<result> method detects
924	whether an exception as thrown (it is stored inside the $txn object)	1322	whether an exception as thrown (it is stored inside the $txn object)
925	and just throws the exception, which means connection errors and other	1323	and just throws the exception, which means connection errors and other
926	problems get reported tot he code that tries to use the result, not in a	1324	problems get reported tot he code that tries to use the result, not in a
927	random callback.	1325	random callback.
928		1326
…		…
959		1357
960	my $quit = AnyEvent->condvar;	1358	my $quit = AnyEvent->condvar;
961		1359
962	$fcp->txn_client_get ($url)->cb (sub {	1360	$fcp->txn_client_get ($url)->cb (sub {
963	...	1361	...
964	$quit->broadcast;	1362	$quit->send;
965	});	1363	});
966		1364
967	$quit->wait;	1365	$quit->recv;
968		1366
969		1367
970	=head1 BENCHMARKS	1368	=head1 BENCHMARKS
971		1369
972	To give you an idea of the performance and overheads that AnyEvent adds	1370	To give you an idea of the performance and overheads that AnyEvent adds
…		…
974	of various event loops I prepared some benchmarks.	1372	of various event loops I prepared some benchmarks.
975		1373
976	=head2 BENCHMARKING ANYEVENT OVERHEAD	1374	=head2 BENCHMARKING ANYEVENT OVERHEAD
977		1375
978	Here is a benchmark of various supported event models used natively and	1376	Here is a benchmark of various supported event models used natively and
979	through anyevent. The benchmark creates a lot of timers (with a zero	1377	through AnyEvent. The benchmark creates a lot of timers (with a zero
980	timeout) and I/O watchers (watching STDOUT, a pty, to become writable,	1378	timeout) and I/O watchers (watching STDOUT, a pty, to become writable,
981	which it is), lets them fire exactly once and destroys them again.	1379	which it is), lets them fire exactly once and destroys them again.
982		1380
983	Source code for this benchmark is found as F<eg/bench> in the AnyEvent	1381	Source code for this benchmark is found as F<eg/bench> in the AnyEvent
984	distribution.	1382	distribution.
…		…
1001	all watchers, to avoid adding memory overhead. That means closure creation	1399	all watchers, to avoid adding memory overhead. That means closure creation
1002	and memory usage is not included in the figures.	1400	and memory usage is not included in the figures.
1003		1401
1004	I<invoke> is the time, in microseconds, used to invoke a simple	1402	I<invoke> is the time, in microseconds, used to invoke a simple
1005	callback. The callback simply counts down a Perl variable and after it was	1403	callback. The callback simply counts down a Perl variable and after it was
1006	invoked "watcher" times, it would C<< ->broadcast >> a condvar once to	1404	invoked "watcher" times, it would C<< ->send >> a condvar once to
1007	signal the end of this phase.	1405	signal the end of this phase.
1008		1406
1009	I<destroy> is the time, in microseconds, that it takes to destroy a single	1407	I<destroy> is the time, in microseconds, that it takes to destroy a single
1010	watcher.	1408	watcher.
1011		1409
…		…
1107		1505
1108	=back	1506	=back
1109		1507
1110	=head2 BENCHMARKING THE LARGE SERVER CASE	1508	=head2 BENCHMARKING THE LARGE SERVER CASE
1111		1509
1112	This benchmark atcually benchmarks the event loop itself. It works by	1510	This benchmark actually benchmarks the event loop itself. It works by
1113	creating a number of "servers": each server consists of a socketpair, a	1511	creating a number of "servers": each server consists of a socket pair, a
1114	timeout watcher that gets reset on activity (but never fires), and an I/O	1512	timeout watcher that gets reset on activity (but never fires), and an I/O
1115	watcher waiting for input on one side of the socket. Each time the socket	1513	watcher waiting for input on one side of the socket. Each time the socket
1116	watcher reads a byte it will write that byte to a random other "server".	1514	watcher reads a byte it will write that byte to a random other "server".
1117		1515
1118	The effect is that there will be a lot of I/O watchers, only part of which	1516	The effect is that there will be a lot of I/O watchers, only part of which
1119	are active at any one point (so there is a constant number of active	1517	are active at any one point (so there is a constant number of active
1120	fds for each loop iterstaion, but which fds these are is random). The	1518	fds for each loop iteration, but which fds these are is random). The
1121	timeout is reset each time something is read because that reflects how	1519	timeout is reset each time something is read because that reflects how
1122	most timeouts work (and puts extra pressure on the event loops).	1520	most timeouts work (and puts extra pressure on the event loops).
1123		1521
1124	In this benchmark, we use 10000 socketpairs (20000 sockets), of which 100	1522	In this benchmark, we use 10000 socket pairs (20000 sockets), of which 100
1125	(1%) are active. This mirrors the activity of large servers with many	1523	(1%) are active. This mirrors the activity of large servers with many
1126	connections, most of which are idle at any one point in time.	1524	connections, most of which are idle at any one point in time.
1127		1525
1128	Source code for this benchmark is found as F<eg/bench2> in the AnyEvent	1526	Source code for this benchmark is found as F<eg/bench2> in the AnyEvent
1129	distribution.	1527	distribution.
…		…
1131	=head3 Explanation of the columns	1529	=head3 Explanation of the columns
1132		1530
1133	I<sockets> is the number of sockets, and twice the number of "servers" (as	1531	I<sockets> is the number of sockets, and twice the number of "servers" (as
1134	each server has a read and write socket end).	1532	each server has a read and write socket end).
1135		1533
1136	I<create> is the time it takes to create a socketpair (which is	1534	I<create> is the time it takes to create a socket pair (which is
1137	nontrivial) and two watchers: an I/O watcher and a timeout watcher.	1535	nontrivial) and two watchers: an I/O watcher and a timeout watcher.
1138		1536
1139	I<request>, the most important value, is the time it takes to handle a	1537	I<request>, the most important value, is the time it takes to handle a
1140	single "request", that is, reading the token from the pipe and forwarding	1538	single "request", that is, reading the token from the pipe and forwarding
1141	it to another server. This includes deleting the old timeout and creating	1539	it to another server. This includes deleting the old timeout and creating
…		…
1214	speed most when you have lots of watchers, not when you only have a few of	1612	speed most when you have lots of watchers, not when you only have a few of
1215	them).	1613	them).
1216		1614
1217	EV is again fastest.	1615	EV is again fastest.
1218		1616
1219	Perl again comes second. It is noticably faster than the C-based event	1617	Perl again comes second. It is noticeably faster than the C-based event
1220	loops Event and Glib, although the difference is too small to really	1618	loops Event and Glib, although the difference is too small to really
1221	matter.	1619	matter.
1222		1620
1223	POE also performs much better in this case, but is is still far behind the	1621	POE also performs much better in this case, but is is still far behind the
1224	others.	1622	others.
…		…
1257		1655
1258	BEGIN { delete $ENV{PERL_ANYEVENT_MODEL} }	1656	BEGIN { delete $ENV{PERL_ANYEVENT_MODEL} }
1259		1657
1260	use AnyEvent;	1658	use AnyEvent;
1261		1659
		1660	Similar considerations apply to $ENV{PERL_ANYEVENT_VERBOSE}, as that can
		1661	be used to probe what backend is used and gain other information (which is
		1662	probably even less useful to an attacker than PERL_ANYEVENT_MODEL).
		1663
1262		1664
1263	=head1 SEE ALSO	1665	=head1 SEE ALSO
1264		1666
1265	Event modules: L<Coro::EV>, L<EV>, L<EV::Glib>, L<Glib::EV>,	1667	Utility functions: L<AnyEvent::Util>.
1266	L<Coro::Event>, L<Event>, L<Glib::Event>, L<Glib>, L<Coro>, L<Tk>,	1668
		1669	Event modules: L<EV>, L<EV::Glib>, L<Glib::EV>, L<Event>, L<Glib::Event>,
1267	L<Event::Lib>, L<Qt>, L<POE>.	1670	L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>.
1268		1671
1269	Implementations: L<AnyEvent::Impl::CoroEV>, L<AnyEvent::Impl::EV>,	1672	Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>,
1270	L<AnyEvent::Impl::CoroEvent>, L<AnyEvent::Impl::Event>, L<AnyEvent::Impl::Glib>,	1673	L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>,
1271	L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>, L<AnyEvent::Impl::EventLib>,	1674	L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>,
1272	L<AnyEvent::Impl::Qt>, L<AnyEvent::Impl::POE>.	1675	L<AnyEvent::Impl::POE>.
1273		1676
		1677	Non-blocking file handles, sockets, TCP clients and
		1678	servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>.
		1679
		1680	Asynchronous DNS: L<AnyEvent::DNS>.
		1681
		1682	Coroutine support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>, L<Coro::Event>,
		1683
1274	Nontrivial usage examples: L<Net::FCP>, L<Net::XMPP2>.	1684	Nontrivial usage examples: L<Net::FCP>, L<Net::XMPP2>, L<AnyEvent::DNS>.
1275		1685
1276		1686
1277	=head1 AUTHOR	1687	=head1 AUTHOR
1278		1688
1279	Marc Lehmann <schmorp@schmorp.de>	1689	Marc Lehmann <schmorp@schmorp.de>

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Comparing AnyEvent/lib/AnyEvent.pm (file contents): Revision 1.104 by root, Wed Apr 30 11:40:22 2008 UTC vs. Revision 1.146 by root, Fri May 30 21:38:46 2008 UTC

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Comparing AnyEvent/lib/AnyEvent.pm (file contents):
Revision 1.104 by root, Wed Apr 30 11:40:22 2008 UTC vs.
Revision 1.146 by root, Fri May 30 21:38:46 2008 UTC