[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 1.164 by root, Tue Jul 8 19:50:25 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
		23	=head1 INTRODUCTION/TUTORIAL
		24
		25	This manpage is mainly a reference manual. If you are interested
		26	in a tutorial or some gentle introduction, have a look at the
		27	L<AnyEvent::Intro> manpage.
22		28
23	=head1 WHY YOU SHOULD USE THIS MODULE (OR NOT)	29	=head1 WHY YOU SHOULD USE THIS MODULE (OR NOT)
24		30
25	Glib, POE, IO::Async, Event... CPAN offers event models by the dozen	31	Glib, POE, IO::Async, Event... CPAN offers event models by the dozen
26	nowadays. So what is different about AnyEvent?	32	nowadays. So what is different about AnyEvent?
…		…
48	isn't itself. What's worse, all the potential users of your module are	54	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.	55	I<also> forced to use the same event loop you use.
50		56
51	AnyEvent is different: AnyEvent + POE works fine. AnyEvent + Glib works	57	AnyEvent is different: AnyEvent + POE works fine. AnyEvent + Glib works
52	fine. AnyEvent + Tk works fine etc. etc. but none of these work together	58	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	59	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,	60	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	61	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	62	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	63	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).	64	event loops to AnyEvent, too, so it is future-proof).
59		65
60	In addition to being free of having to use I<the one and only true event	66	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	67	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	68	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	69	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	70	offering the functionality that is necessary, in as thin as a wrapper as
65	technically possible.	71	technically possible.
66		72
		73	Of course, AnyEvent comes with a big (and fully optional!) toolbox
		74	of useful functionality, such as an asynchronous DNS resolver, 100%
		75	non-blocking connects (even with TLS/SSL, IPv6 and on broken platforms
		76	such as Windows) and lots of real-world knowledge and workarounds for
		77	platform bugs and differences.
		78
67	Of course, if you want lots of policy (this can arguably be somewhat	79	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	80	useful) and you want to force your users to use the one and only event
69	model, you should I<not> use this module.	81	model, you should I<not> use this module.
70		82
71	=head1 DESCRIPTION	83	=head1 DESCRIPTION
72		84
…		…
78	The interface itself is vaguely similar, but not identical to the L<Event>	90	The interface itself is vaguely similar, but not identical to the L<Event>
79	module.	91	module.
80		92
81	During the first call of any watcher-creation method, the module tries	93	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	94	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>,	95	following modules is already loaded: L<EV>,
84	L<Event>, L<Glib>, L<AnyEvent::Impl::Perl>, L<Tk>, L<Event::Lib>, L<Qt>,	96	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	97	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	98	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	99	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	100	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	114	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...	115	use AnyEvent so their modules work together with others seamlessly...
104		116
105	The pure-perl implementation of AnyEvent is called	117	The pure-perl implementation of AnyEvent is called
106	C<AnyEvent::Impl::Perl>. Like other event modules you can load it	118	C<AnyEvent::Impl::Perl>. Like other event modules you can load it
107	explicitly.	119	explicitly and enjoy the high availability of that event loop :)
108		120
109	=head1 WATCHERS	121	=head1 WATCHERS
110		122
111	AnyEvent has the central concept of a I<watcher>, which is an object that	123	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	124	stores relevant data for each kind of event you are waiting for, such as
113	the callback to call, the filehandle to watch, etc.	125	the callback to call, the file handle to watch, etc.
114		126
115	These watchers are normal Perl objects with normal Perl lifetime. After	127	These watchers are normal Perl objects with normal Perl lifetime. After
116	creating a watcher it will immediately "watch" for events and invoke the	128	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	129	callback when the event occurs (of course, only when the event model
118	is in control).	130	is in control).
…		…
126	Many watchers either are used with "recursion" (repeating timers for	138	Many watchers either are used with "recursion" (repeating timers for
127	example), or need to refer to their watcher object in other ways.	139	example), or need to refer to their watcher object in other ways.
128		140
129	An any way to achieve that is this pattern:	141	An any way to achieve that is this pattern:
130		142
131	my $w; $w = AnyEvent->type (arg => value ..., cb => sub {	143	my $w; $w = AnyEvent->type (arg => value ..., cb => sub {
132	# you can use $w here, for example to undef it	144	# you can use $w here, for example to undef it
133	undef $w;	145	undef $w;
134	});	146	});
135		147
136	Note that C<my $w; $w => combination. This is necessary because in Perl,	148	Note that C<my $w; $w => combination. This is necessary because in Perl,
137	my variables are only visible after the statement in which they are	149	my variables are only visible after the statement in which they are
138	declared.	150	declared.
139		151
…		…
158		170
159	Some event loops issue spurious readyness notifications, so you should	171	Some event loops issue spurious readyness notifications, so you should
160	always use non-blocking calls when reading/writing from/to your file	172	always use non-blocking calls when reading/writing from/to your file
161	handles.	173	handles.
162		174
163	Example:
164
165	# wait for readability of STDIN, then read a line and disable the watcher	175	Example: wait for readability of STDIN, then read a line and disable the
		176	watcher.
		177
166	my $w; $w = AnyEvent->io (fh => \*STDIN, poll => 'r', cb => sub {	178	my $w; $w = AnyEvent->io (fh => \*STDIN, poll => 'r', cb => sub {
167	chomp (my $input = <STDIN>);	179	chomp (my $input = <STDIN>);
168	warn "read: $input\n";	180	warn "read: $input\n";
169	undef $w;	181	undef $w;
170	});	182	});
…		…
180		192
181	Although the callback might get passed parameters, their value and	193	Although the callback might get passed parameters, their value and
182	presence is undefined and you cannot rely on them. Portable AnyEvent	194	presence is undefined and you cannot rely on them. Portable AnyEvent
183	callbacks cannot use arguments passed to time watcher callbacks.	195	callbacks cannot use arguments passed to time watcher callbacks.
184		196
185	The timer callback will be invoked at most once: if you want a repeating	197	The callback will normally be invoked once only. If you specify another
186	timer you have to create a new watcher (this is a limitation by both Tk	198	parameter, C<interval>, as a positive number, then the callback will be
187	and Glib).	199	invoked regularly at that interval (in fractional seconds) after the first
		200	invocation.
188		201
189	Example:	202	The callback will be rescheduled before invoking the callback, but no
		203	attempt is done to avoid timer drift in most backends, so the interval is
		204	only approximate.
190		205
191	# fire an event after 7.7 seconds	206	Example: fire an event after 7.7 seconds.
		207
192	my $w = AnyEvent->timer (after => 7.7, cb => sub {	208	my $w = AnyEvent->timer (after => 7.7, cb => sub {
193	warn "timeout\n";	209	warn "timeout\n";
194	});	210	});
195		211
196	# to cancel the timer:	212	# to cancel the timer:
197	undef $w;	213	undef $w;
198		214
199	Example 2:
200
201	# fire an event after 0.5 seconds, then roughly every second	215	Example 2: fire an event after 0.5 seconds, then roughly every second.
202	my $w;
203		216
204	my $cb = sub {
205	# cancel the old timer while creating a new one
206	$w = AnyEvent->timer (after => 1, cb => $cb);	217	my $w = AnyEvent->timer (after => 0.5, interval => 1, cb => sub {
		218	warn "timeout\n";
207	};	219	};
208
209	# start the "loop" by creating the first watcher
210	$w = AnyEvent->timer (after => 0.5, cb => $cb);
211		220
212	=head3 TIMING ISSUES	221	=head3 TIMING ISSUES
213		222
214	There are two ways to handle timers: based on real time (relative, "fire	223	There are two ways to handle timers: based on real time (relative, "fire
215	in 10 seconds") and based on wallclock time (absolute, "fire at 12	224	in 10 seconds") and based on wallclock time (absolute, "fire at 12
…		…
227	timers.	236	timers.
228		237
229	AnyEvent always prefers relative timers, if available, matching the	238	AnyEvent always prefers relative timers, if available, matching the
230	AnyEvent API.	239	AnyEvent API.
231		240
		241	AnyEvent has two additional methods that return the "current time":
		242
		243	=over 4
		244
		245	=item AnyEvent->time
		246
		247	This returns the "current wallclock time" as a fractional number of
		248	seconds since the Epoch (the same thing as C<time> or C<Time::HiRes::time>
		249	return, and the result is guaranteed to be compatible with those).
		250
		251	It progresses independently of any event loop processing, i.e. each call
		252	will check the system clock, which usually gets updated frequently.
		253
		254	=item AnyEvent->now
		255
		256	This also returns the "current wallclock time", but unlike C<time>, above,
		257	this value might change only once per event loop iteration, depending on
		258	the event loop (most return the same time as C<time>, above). This is the
		259	time that AnyEvent's timers get scheduled against.
		260
		261	I<In almost all cases (in all cases if you don't care), this is the
		262	function to call when you want to know the current time.>
		263
		264	This function is also often faster then C<< AnyEvent->time >>, and
		265	thus the preferred method if you want some timestamp (for example,
		266	L<AnyEvent::Handle> uses this to update it's activity timeouts).
		267
		268	The rest of this section is only of relevance if you try to be very exact
		269	with your timing, you can skip it without bad conscience.
		270
		271	For a practical example of when these times differ, consider L<Event::Lib>
		272	and L<EV> and the following set-up:
		273
		274	The event loop is running and has just invoked one of your callback at
		275	time=500 (assume no other callbacks delay processing). In your callback,
		276	you wait a second by executing C<sleep 1> (blocking the process for a
		277	second) and then (at time=501) you create a relative timer that fires
		278	after three seconds.
		279
		280	With L<Event::Lib>, C<< AnyEvent->time >> and C<< AnyEvent->now >> will
		281	both return C<501>, because that is the current time, and the timer will
		282	be scheduled to fire at time=504 (C<501> + C<3>).
		283
		284	With L<EV>, C<< AnyEvent->time >> returns C<501> (as that is the current
		285	time), but C<< AnyEvent->now >> returns C<500>, as that is the time the
		286	last event processing phase started. With L<EV>, your timer gets scheduled
		287	to run at time=503 (C<500> + C<3>).
		288
		289	In one sense, L<Event::Lib> is more exact, as it uses the current time
		290	regardless of any delays introduced by event processing. However, most
		291	callbacks do not expect large delays in processing, so this causes a
		292	higher drift (and a lot more system calls to get the current time).
		293
		294	In another sense, L<EV> is more exact, as your timer will be scheduled at
		295	the same time, regardless of how long event processing actually took.
		296
		297	In either case, if you care (and in most cases, you don't), then you
		298	can get whatever behaviour you want with any event loop, by taking the
		299	difference between C<< AnyEvent->time >> and C<< AnyEvent->now >> into
		300	account.
		301
		302	=back
		303
232	=head2 SIGNAL WATCHERS	304	=head2 SIGNAL WATCHERS
233		305
234	You can watch for signals using a signal watcher, C<signal> is the signal	306	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	307	I<name> without any C<SIG> prefix, C<cb> is the Perl callback to
236	be invoked whenever a signal occurs.	308	be invoked whenever a signal occurs.
237		309
238	Although the callback might get passed parameters, their value and	310	Although the callback might get passed parameters, their value and
239	presence is undefined and you cannot rely on them. Portable AnyEvent	311	presence is undefined and you cannot rely on them. Portable AnyEvent
240	callbacks cannot use arguments passed to signal watcher callbacks.	312	callbacks cannot use arguments passed to signal watcher callbacks.
241		313
242	Multiple signal occurances can be clumped together into one callback	314	Multiple signal occurrences can be clumped together into one callback
243	invocation, and callback invocation will be synchronous. synchronous means	315	invocation, and callback invocation will be synchronous. Synchronous means
244	that it might take a while until the signal gets handled by the process,	316	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.	317	but it is guaranteed not to interrupt any other callbacks.
246		318
247	The main advantage of using these watchers is that you can share a signal	319	The main advantage of using these watchers is that you can share a signal
248	between multiple watchers.	320	between multiple watchers.
249		321
250	This watcher might use C<%SIG>, so programs overwriting those signals	322	This watcher might use C<%SIG>, so programs overwriting those signals
…		…
277	AnyEvent program, you I<have> to create at least one watcher before you	349	AnyEvent program, you I<have> to create at least one watcher before you
278	C<fork> the child (alternatively, you can call C<AnyEvent::detect>).	350	C<fork> the child (alternatively, you can call C<AnyEvent::detect>).
279		351
280	Example: fork a process and wait for it	352	Example: fork a process and wait for it
281		353
282	my $done = AnyEvent->condvar;	354	my $done = AnyEvent->condvar;
283		355
284	AnyEvent::detect; # force event module to be initialised
285
286	my $pid = fork or exit 5;	356	my $pid = fork or exit 5;
287		357
288	my $w = AnyEvent->child (	358	my $w = AnyEvent->child (
289	pid => $pid,	359	pid => $pid,
290	cb => sub {	360	cb => sub {
291	my ($pid, $status) = @_;	361	my ($pid, $status) = @_;
292	warn "pid $pid exited with status $status";	362	warn "pid $pid exited with status $status";
293	$done->broadcast;	363	$done->send;
294	},	364	},
295	);	365	);
296		366
297	# do something else, then wait for process exit	367	# do something else, then wait for process exit
298	$done->wait;	368	$done->recv;
299		369
300	=head2 CONDITION VARIABLES	370	=head2 CONDITION VARIABLES
301		371
		372	If you are familiar with some event loops you will know that all of them
		373	require you to run some blocking "loop", "run" or similar function that
		374	will actively watch for new events and call your callbacks.
		375
		376	AnyEvent is different, it expects somebody else to run the event loop and
		377	will only block when necessary (usually when told by the user).
		378
		379	The instrument to do that is called a "condition variable", so called
		380	because they represent a condition that must become true.
		381
302	Condition variables can be created by calling the C<< AnyEvent->condvar >>	382	Condition variables can be created by calling the C<< AnyEvent->condvar
303	method without any arguments.	383	>> method, usually without arguments. The only argument pair allowed is
		384	C<cb>, which specifies a callback to be called when the condition variable
		385	becomes true.
304		386
305	A condition variable waits for a condition - precisely that the C<<	387	After creation, the condition variable is "false" until it becomes "true"
306	->broadcast >> method has been called.	388	by calling the C<send> method (or calling the condition variable as if it
		389	were a callback, read about the caveats in the description for the C<<
		390	->send >> method).
307		391
308	They are very useful to signal that a condition has been fulfilled, for	392	Condition variables are similar to callbacks, except that you can
		393	optionally wait for them. They can also be called merge points - points
		394	in time where multiple outstanding events have been processed. And yet
		395	another way to call them is transactions - each condition variable can be
		396	used to represent a transaction, which finishes at some point and delivers
		397	a result.
		398
		399	Condition variables are very useful to signal that something has finished,
309	example, if you write a module that does asynchronous http requests,	400	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	401	then a condition variable would be the ideal candidate to signal the
311	availability of results.	402	availability of results. The user can either act when the callback is
		403	called or can synchronously C<< ->recv >> for the results.
312		404
313	You can also use condition variables to block your main program until	405	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	406	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<<	407	could C<< ->recv >> in your main program until the user clicks the Quit
316	->broadcast >> the "quit" event.	408	button of your app, which would C<< ->send >> the "quit" event.
317		409
318	Note that condition variables recurse into the event loop - if you have	410	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	411	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	412	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,	413	you should avoid making a blocking wait yourself, at least in callbacks,
322	as this asks for trouble.	414	as this asks for trouble.
323		415
324	This object has two methods:	416	Condition variables are represented by hash refs in perl, and the keys
		417	used by AnyEvent itself are all named C<_ae_XXX> to make subclassing
		418	easy (it is often useful to build your own transaction class on top of
		419	AnyEvent). To subclass, use C<AnyEvent::CondVar> as base class and call
		420	it's C<new> method in your own C<new> method.
		421
		422	There are two "sides" to a condition variable - the "producer side" which
		423	eventually calls C<< -> send >>, and the "consumer side", which waits
		424	for the send to occur.
		425
		426	Example: wait for a timer.
		427
		428	# wait till the result is ready
		429	my $result_ready = AnyEvent->condvar;
		430
		431	# do something such as adding a timer
		432	# or socket watcher the calls $result_ready->send
		433	# when the "result" is ready.
		434	# in this case, we simply use a timer:
		435	my $w = AnyEvent->timer (
		436	after => 1,
		437	cb => sub { $result_ready->send },
		438	);
		439
		440	# this "blocks" (while handling events) till the callback
		441	# calls send
		442	$result_ready->recv;
		443
		444	Example: wait for a timer, but take advantage of the fact that
		445	condition variables are also code references.
		446
		447	my $done = AnyEvent->condvar;
		448	my $delay = AnyEvent->timer (after => 5, cb => $done);
		449	$done->recv;
		450
		451	=head3 METHODS FOR PRODUCERS
		452
		453	These methods should only be used by the producing side, i.e. the
		454	code/module that eventually sends the signal. Note that it is also
		455	the producer side which creates the condvar in most cases, but it isn't
		456	uncommon for the consumer to create it as well.
325		457
326	=over 4	458	=over 4
327		459
		460	=item $cv->send (...)
		461
		462	Flag the condition as ready - a running C<< ->recv >> and all further
		463	calls to C<recv> will (eventually) return after this method has been
		464	called. If nobody is waiting the send will be remembered.
		465
		466	If a callback has been set on the condition variable, it is called
		467	immediately from within send.
		468
		469	Any arguments passed to the C<send> call will be returned by all
		470	future C<< ->recv >> calls.
		471
		472	Condition variables are overloaded so one can call them directly
		473	(as a code reference). Calling them directly is the same as calling
		474	C<send>. Note, however, that many C-based event loops do not handle
		475	overloading, so as tempting as it may be, passing a condition variable
		476	instead of a callback does not work. Both the pure perl and EV loops
		477	support overloading, however, as well as all functions that use perl to
		478	invoke a callback (as in L<AnyEvent::Socket> and L<AnyEvent::DNS> for
		479	example).
		480
		481	=item $cv->croak ($error)
		482
		483	Similar to send, but causes all call's to C<< ->recv >> to invoke
		484	C<Carp::croak> with the given error message/object/scalar.
		485
		486	This can be used to signal any errors to the condition variable
		487	user/consumer.
		488
		489	=item $cv->begin ([group callback])
		490
328	=item $cv->wait	491	=item $cv->end
329		492
330	Wait (blocking if necessary) until the C<< ->broadcast >> method has been	493	These two methods are EXPERIMENTAL and MIGHT CHANGE.
		494
		495	These two methods can be used to combine many transactions/events into
		496	one. For example, a function that pings many hosts in parallel might want
		497	to use a condition variable for the whole process.
		498
		499	Every call to C<< ->begin >> will increment a counter, and every call to
		500	C<< ->end >> will decrement it. If the counter reaches C<0> in C<< ->end
		501	>>, the (last) callback passed to C<begin> will be executed. That callback
		502	is I<supposed> to call C<< ->send >>, but that is not required. If no
		503	callback was set, C<send> will be called without any arguments.
		504
		505	Let's clarify this with the ping example:
		506
		507	my $cv = AnyEvent->condvar;
		508
		509	my %result;
		510	$cv->begin (sub { $cv->send (\%result) });
		511
		512	for my $host (@list_of_hosts) {
		513	$cv->begin;
		514	ping_host_then_call_callback $host, sub {
		515	$result{$host} = ...;
		516	$cv->end;
		517	};
		518	}
		519
		520	$cv->end;
		521
		522	This code fragment supposedly pings a number of hosts and calls
		523	C<send> after results for all then have have been gathered - in any
		524	order. To achieve this, the code issues a call to C<begin> when it starts
		525	each ping request and calls C<end> when it has received some result for
		526	it. Since C<begin> and C<end> only maintain a counter, the order in which
		527	results arrive is not relevant.
		528
		529	There is an additional bracketing call to C<begin> and C<end> outside the
		530	loop, which serves two important purposes: first, it sets the callback
		531	to be called once the counter reaches C<0>, and second, it ensures that
		532	C<send> is called even when C<no> hosts are being pinged (the loop
		533	doesn't execute once).
		534
		535	This is the general pattern when you "fan out" into multiple subrequests:
		536	use an outer C<begin>/C<end> pair to set the callback and ensure C<end>
		537	is called at least once, and then, for each subrequest you start, call
		538	C<begin> and for each subrequest you finish, call C<end>.
		539
		540	=back
		541
		542	=head3 METHODS FOR CONSUMERS
		543
		544	These methods should only be used by the consuming side, i.e. the
		545	code awaits the condition.
		546
		547	=over 4
		548
		549	=item $cv->recv
		550
		551	Wait (blocking if necessary) until the C<< ->send >> or C<< ->croak
331	called on c<$cv>, while servicing other watchers normally.	552	>> methods have been called on c<$cv>, while servicing other watchers
		553	normally.
332		554
333	You can only wait once on a condition - additional calls will return	555	You can only wait once on a condition - additional calls are valid but
334	immediately.	556	will return immediately.
		557
		558	If an error condition has been set by calling C<< ->croak >>, then this
		559	function will call C<croak>.
		560
		561	In list context, all parameters passed to C<send> will be returned,
		562	in scalar context only the first one will be returned.
335		563
336	Not all event models support a blocking wait - some die in that case	564	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	565	(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	566	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	567	caller decide whether the call will block or not (for example, by coupling
340	condition variables with some kind of request results and supporting	568	condition variables with some kind of request results and supporting
341	callbacks so the caller knows that getting the result will not block,	569	callbacks so the caller knows that getting the result will not block,
342	while still suppporting blocking waits if the caller so desires).	570	while still supporting blocking waits if the caller so desires).
343		571
344	Another reason I<never> to C<< ->wait >> in a module is that you cannot	572	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	573	sensibly have two C<< ->recv >>'s in parallel, as that would require
346	multiple interpreters or coroutines/threads, none of which C<AnyEvent>	574	multiple interpreters or coroutines/threads, none of which C<AnyEvent>
347	can supply (the coroutine-aware backends L<AnyEvent::Impl::CoroEV> and	575	can supply.
348	L<AnyEvent::Impl::CoroEvent> explicitly support concurrent C<< ->wait >>'s
349	from different coroutines, however).
350		576
351	=item $cv->broadcast	577	The L<Coro> module, however, I<can> and I<does> supply coroutines and, in
		578	fact, L<Coro::AnyEvent> replaces AnyEvent's condvars by coroutine-safe
		579	versions and also integrates coroutines into AnyEvent, making blocking
		580	C<< ->recv >> calls perfectly safe as long as they are done from another
		581	coroutine (one that doesn't run the event loop).
352		582
353	Flag the condition as ready - a running C<< ->wait >> and all further	583	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	584	only calling C<< ->recv >> from within that callback (or at a later
355	called. If nobody is waiting the broadcast will be remembered..	585	time). This will work even when the event loop does not support blocking
		586	waits otherwise.
		587
		588	=item $bool = $cv->ready
		589
		590	Returns true when the condition is "true", i.e. whether C<send> or
		591	C<croak> have been called.
		592
		593	=item $cb = $cv->cb ([new callback])
		594
		595	This is a mutator function that returns the callback set and optionally
		596	replaces it before doing so.
		597
		598	The callback will be called when the condition becomes "true", i.e. when
		599	C<send> or C<croak> are called, with the only argument being the condition
		600	variable itself. Calling C<recv> inside the callback or at any later time
		601	is guaranteed not to block.
356		602
357	=back	603	=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	$result_ready->wait;
376		604
377	=head1 GLOBAL VARIABLES AND FUNCTIONS	605	=head1 GLOBAL VARIABLES AND FUNCTIONS
378		606
379	=over 4	607	=over 4
380		608
…		…
386	C<AnyEvent::Impl:xxx> modules, but can be any other class in the case	614	C<AnyEvent::Impl:xxx> modules, but can be any other class in the case
387	AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode>).	615	AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode>).
388		616
389	The known classes so far are:	617	The known classes so far are:
390		618
391	AnyEvent::Impl::CoroEV based on Coro::EV, best choice.
392	AnyEvent::Impl::CoroEvent based on Coro::Event, second best choice.
393	AnyEvent::Impl::EV based on EV (an interface to libev, best choice).	619	AnyEvent::Impl::EV based on EV (an interface to libev, best choice).
394	AnyEvent::Impl::Event based on Event, second best choice.	620	AnyEvent::Impl::Event based on Event, second best choice.
395	AnyEvent::Impl::Perl pure-perl implementation, fast and portable.	621	AnyEvent::Impl::Perl pure-perl implementation, fast and portable.
396	AnyEvent::Impl::Glib based on Glib, third-best choice.	622	AnyEvent::Impl::Glib based on Glib, third-best choice.
397	AnyEvent::Impl::Tk based on Tk, very bad choice.	623	AnyEvent::Impl::Tk based on Tk, very bad choice.
…		…
414	Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model	640	Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model
415	if necessary. You should only call this function right before you would	641	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	642	have created an AnyEvent watcher anyway, that is, as late as possible at
417	runtime.	643	runtime.
418		644
		645	=item $guard = AnyEvent::post_detect { BLOCK }
		646
		647	Arranges for the code block to be executed as soon as the event model is
		648	autodetected (or immediately if this has already happened).
		649
		650	If called in scalar or list context, then it creates and returns an object
		651	that automatically removes the callback again when it is destroyed. See
		652	L<Coro::BDB> for a case where this is useful.
		653
		654	=item @AnyEvent::post_detect
		655
		656	If there are any code references in this array (you can C<push> to it
		657	before or after loading AnyEvent), then they will called directly after
		658	the event loop has been chosen.
		659
		660	You should check C<$AnyEvent::MODEL> before adding to this array, though:
		661	if it contains a true value then the event loop has already been detected,
		662	and the array will be ignored.
		663
		664	Best use C<AnyEvent::post_detect { BLOCK }> instead.
		665
419	=back	666	=back
420		667
421	=head1 WHAT TO DO IN A MODULE	668	=head1 WHAT TO DO IN A MODULE
422		669
423	As a module author, you should C<use AnyEvent> and call AnyEvent methods	670	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	673	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	674	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	675	by calling AnyEvent in your module body you force the user of your module
429	to load the event module first.	676	to load the event module first.
430		677
431	Never call C<< ->wait >> on a condition variable unless you I<know> that	678	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	679	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	680	because it will stall the whole program, and the whole point of using
434	events is to stay interactive.	681	events is to stay interactive.
435		682
436	It is fine, however, to call C<< ->wait >> when the user of your module	683	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	684	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 >>	685	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).	686	freely, as the user of your module knows what she is doing. always).
440		687
441	=head1 WHAT TO DO IN THE MAIN PROGRAM	688	=head1 WHAT TO DO IN THE MAIN PROGRAM
442		689
443	There will always be a single main program - the only place that should	690	There will always be a single main program - the only place that should
…		…
445		692
446	If it doesn't care, it can just "use AnyEvent" and use it itself, or not	693	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	694	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.	695	decide which implementation to chose if some module relies on it.
449		696
450	If the main program relies on a specific event model. For example, in	697	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	698	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	699	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	700	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	701	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	702	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.	703	might chose the wrong one unless you load the correct one yourself.
457		704
458	You can chose to use a rather inefficient pure-perl implementation by	705	You can chose to use a pure-perl implementation by loading the
459	loading the C<AnyEvent::Impl::Perl> module, which gives you similar	706	C<AnyEvent::Impl::Perl> module, which gives you similar behaviour
460	behaviour everywhere, but letting AnyEvent chose is generally better.	707	everywhere, but letting AnyEvent chose the model is generally better.
		708
		709	=head2 MAINLOOP EMULATION
		710
		711	Sometimes (often for short test scripts, or even standalone programs who
		712	only want to use AnyEvent), you do not want to run a specific event loop.
		713
		714	In that case, you can use a condition variable like this:
		715
		716	AnyEvent->condvar->recv;
		717
		718	This has the effect of entering the event loop and looping forever.
		719
		720	Note that usually your program has some exit condition, in which case
		721	it is better to use the "traditional" approach of storing a condition
		722	variable somewhere, waiting for it, and sending it when the program should
		723	exit cleanly.
		724
461		725
462	=head1 OTHER MODULES	726	=head1 OTHER MODULES
463		727
464	The following is a non-exhaustive list of additional modules that use	728	The following is a non-exhaustive list of additional modules that use
465	AnyEvent and can therefore be mixed easily with other AnyEvent modules	729	AnyEvent and can therefore be mixed easily with other AnyEvent modules
…		…
471	=item L<AnyEvent::Util>	735	=item L<AnyEvent::Util>
472		736
473	Contains various utility functions that replace often-used but blocking	737	Contains various utility functions that replace often-used but blocking
474	functions such as C<inet_aton> by event-/callback-based versions.	738	functions such as C<inet_aton> by event-/callback-based versions.
475		739
		740	=item L<AnyEvent::Socket>
		741
		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
476	=item L<AnyEvent::Handle>	746	=item L<AnyEvent::Handle>
477		747
478	Provide read and write buffers and manages watchers for reads and writes.	748	Provide read and write buffers, manages watchers for reads and writes,
		749	supports raw and formatted I/O, I/O queued and fully transparent and
		750	non-blocking SSL/TLS.
479		751
480	=item L<AnyEvent::Socket>	752	=item L<AnyEvent::DNS>
481		753
482	Provides a means to do non-blocking connects, accepts etc.	754	Provides rich asynchronous DNS resolver capabilities.
		755
		756	=item L<AnyEvent::HTTP>
		757
		758	A simple-to-use HTTP library that is capable of making a lot of concurrent
		759	HTTP requests.
483		760
484	=item L<AnyEvent::HTTPD>	761	=item L<AnyEvent::HTTPD>
485		762
486	Provides a simple web application server framework.	763	Provides a simple web application server framework.
487		764
488	=item L<AnyEvent::DNS>
489
490	Provides asynchronous DNS resolver capabilities, beyond what
491	L<AnyEvent::Util> offers.
492
493	=item L<AnyEvent::FastPing>	765	=item L<AnyEvent::FastPing>
494		766
495	The fastest ping in the west.	767	The fastest ping in the west.
		768
		769	=item L<AnyEvent::DBI>
		770
		771	Executes L<DBI> requests asynchronously in a proxy process.
		772
		773	=item L<AnyEvent::AIO>
		774
		775	Truly asynchronous I/O, should be in the toolbox of every event
		776	programmer. AnyEvent::AIO transparently fuses L<IO::AIO> and AnyEvent
		777	together.
		778
		779	=item L<AnyEvent::BDB>
		780
		781	Truly asynchronous Berkeley DB access. AnyEvent::BDB transparently fuses
		782	L<BDB> and AnyEvent together.
		783
		784	=item L<AnyEvent::GPSD>
		785
		786	A non-blocking interface to gpsd, a daemon delivering GPS information.
		787
		788	=item L<AnyEvent::IGS>
		789
		790	A non-blocking interface to the Internet Go Server protocol (used by
		791	L<App::IGS>).
496		792
497	=item L<Net::IRC3>	793	=item L<Net::IRC3>
498		794
499	AnyEvent based IRC client module family.	795	AnyEvent based IRC client module family.
500		796
…		…
511		807
512	High level API for event-based execution flow control.	808	High level API for event-based execution flow control.
513		809
514	=item L<Coro>	810	=item L<Coro>
515		811
516	Has special support for AnyEvent.	812	Has special support for AnyEvent via L<Coro::AnyEvent>.
517		813
518	=item L<IO::Lambda>	814	=item L<IO::Lambda>
519		815
520	The lambda approach to I/O - don't ask, look there. Can use AnyEvent.	816	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		817
532	=back	818	=back
533		819
534	=cut	820	=cut
535		821
…		…
538	no warnings;	824	no warnings;
539	use strict;	825	use strict;
540		826
541	use Carp;	827	use Carp;
542		828
543	our $VERSION = '3.3';	829	our $VERSION = 4.2;
544	our $MODEL;	830	our $MODEL;
545		831
546	our $AUTOLOAD;	832	our $AUTOLOAD;
547	our @ISA;	833	our @ISA;
548		834
		835	our @REGISTRY;
		836
		837	our $WIN32;
		838
		839	BEGIN {
		840	my $win32 = ! ! ($^O =~ /mswin32/i);
		841	eval "sub WIN32(){ $win32 }";
		842	}
		843
549	our $verbose = $ENV{PERL_ANYEVENT_VERBOSE}*1;	844	our $verbose = $ENV{PERL_ANYEVENT_VERBOSE}*1;
550		845
551	our @REGISTRY;	846	our %PROTOCOL; # (ipv4\|ipv6) => (1\|2), higher numbers are preferred
		847
		848	{
		849	my $idx;
		850	$PROTOCOL{$_} = ++$idx
		851	for reverse split /\s,\s/,
		852	$ENV{PERL_ANYEVENT_PROTOCOLS} \|\| "ipv4,ipv6";
		853	}
552		854
553	my @models = (	855	my @models = (
554	[Coro::EV:: => AnyEvent::Impl::CoroEV::],
555	[Coro::Event:: => AnyEvent::Impl::CoroEvent::],
556	[EV:: => AnyEvent::Impl::EV::],	856	[EV:: => AnyEvent::Impl::EV::],
557	[Event:: => AnyEvent::Impl::Event::],	857	[Event:: => AnyEvent::Impl::Event::],
558	[Tk:: => AnyEvent::Impl::Tk::],
559	[Wx:: => AnyEvent::Impl::POE::],
560	[Prima:: => AnyEvent::Impl::POE::],
561	[AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl::],	858	[AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl::],
562	# everything below here will not be autoprobed as the pureperl backend should work everywhere	859	# everything below here will not be autoprobed
563	[Glib:: => AnyEvent::Impl::Glib::],	860	# as the pureperl backend should work everywhere
		861	# and is usually faster
		862	[Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles
		863	[Glib:: => AnyEvent::Impl::Glib::], # becomes extremely slow with many watchers
564	[Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy	864	[Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy
565	[Qt:: => AnyEvent::Impl::Qt::], # requires special main program	865	[Qt:: => AnyEvent::Impl::Qt::], # requires special main program
566	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza	866	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza
		867	[Wx:: => AnyEvent::Impl::POE::],
		868	[Prima:: => AnyEvent::Impl::POE::],
567	);	869	);
568		870
569	our %method = map +($_ => 1), qw(io timer signal child condvar broadcast wait one_event DESTROY);	871	our %method = map +($_ => 1), qw(io timer time now signal child condvar one_event DESTROY);
		872
		873	our @post_detect;
		874
		875	sub post_detect(&) {
		876	my ($cb) = @_;
		877
		878	if ($MODEL) {
		879	$cb->();
		880
		881	1
		882	} else {
		883	push @post_detect, $cb;
		884
		885	defined wantarray
		886	? bless \$cb, "AnyEvent::Util::PostDetect"
		887	: ()
		888	}
		889	}
		890
		891	sub AnyEvent::Util::PostDetect::DESTROY {
		892	@post_detect = grep $_ != ${$_[0]}, @post_detect;
		893	}
570		894
571	sub detect() {	895	sub detect() {
572	unless ($MODEL) {	896	unless ($MODEL) {
573	no strict 'refs';	897	no strict 'refs';
		898	local $SIG{__DIE__};
574		899
575	if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) {	900	if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) {
576	my $model = "AnyEvent::Impl::$1";	901	my $model = "AnyEvent::Impl::$1";
577	if (eval "require $model") {	902	if (eval "require $model") {
578	$MODEL = $model;	903	$MODEL = $model;
…		…
608	last;	933	last;
609	}	934	}
610	}	935	}
611		936
612	$MODEL	937	$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.";	938	or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV, Event or Glib.";
614	}	939	}
615	}	940	}
616		941
617	unshift @ISA, $MODEL;	942	unshift @ISA, $MODEL;
618	push @{"$MODEL\::ISA"}, "AnyEvent::Base";	943	push @{"$MODEL\::ISA"}, "AnyEvent::Base";
		944
		945	(shift @post_detect)->() while @post_detect;
619	}	946	}
620		947
621	$MODEL	948	$MODEL
622	}	949	}
623		950
…		…
633	$class->$func (@_);	960	$class->$func (@_);
634	}	961	}
635		962
636	package AnyEvent::Base;	963	package AnyEvent::Base;
637		964
		965	# default implementation for now and time
		966
		967	use Time::HiRes ();
		968
		969	sub time { Time::HiRes::time }
		970	sub now { Time::HiRes::time }
		971
638	# default implementation for ->condvar, ->wait, ->broadcast	972	# default implementation for ->condvar
639		973
640	sub condvar {	974	sub condvar {
641	bless \my $flag, "AnyEvent::Base::CondVar"	975	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	}	976	}
651		977
652	# default implementation for ->signal	978	# default implementation for ->signal
653		979
654	our %SIG_CB;	980	our %SIG_CB;
…		…
670	sub AnyEvent::Base::Signal::DESTROY {	996	sub AnyEvent::Base::Signal::DESTROY {
671	my ($signal, $cb) = @{$_[0]};	997	my ($signal, $cb) = @{$_[0]};
672		998
673	delete $SIG_CB{$signal}{$cb};	999	delete $SIG_CB{$signal}{$cb};
674		1000
675	$SIG{$signal} = 'DEFAULT' unless keys %{ $SIG_CB{$signal} };	1001	delete $SIG{$signal} unless keys %{ $SIG_CB{$signal} };
676	}	1002	}
677		1003
678	# default implementation for ->child	1004	# default implementation for ->child
679		1005
680	our %PID_CB;	1006	our %PID_CB;
…		…
707	or Carp::croak "required option 'pid' is missing";	1033	or Carp::croak "required option 'pid' is missing";
708		1034
709	$PID_CB{$pid}{$arg{cb}} = $arg{cb};	1035	$PID_CB{$pid}{$arg{cb}} = $arg{cb};
710		1036
711	unless ($WNOHANG) {	1037	unless ($WNOHANG) {
712	$WNOHANG = eval { require POSIX; &POSIX::WNOHANG } \|\| 1;	1038	$WNOHANG = eval { local $SIG{__DIE__}; require POSIX; &POSIX::WNOHANG } \|\| 1;
713	}	1039	}
714		1040
715	unless ($CHLD_W) {	1041	unless ($CHLD_W) {
716	$CHLD_W = AnyEvent->signal (signal => 'CHLD', cb => \&_sigchld);	1042	$CHLD_W = AnyEvent->signal (signal => 'CHLD', cb => \&_sigchld);
717	# child could be a zombie already, so make at least one round	1043	# child could be a zombie already, so make at least one round
…		…
727	delete $PID_CB{$pid}{$cb};	1053	delete $PID_CB{$pid}{$cb};
728	delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };	1054	delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };
729		1055
730	undef $CHLD_W unless keys %PID_CB;	1056	undef $CHLD_W unless keys %PID_CB;
731	}	1057	}
		1058
		1059	package AnyEvent::CondVar;
		1060
		1061	our @ISA = AnyEvent::CondVar::Base::;
		1062
		1063	package AnyEvent::CondVar::Base;
		1064
		1065	use overload
		1066	'&{}' => sub { my $self = shift; sub { $self->send (@_) } },
		1067	fallback => 1;
		1068
		1069	sub _send {
		1070	# nop
		1071	}
		1072
		1073	sub send {
		1074	my $cv = shift;
		1075	$cv->{_ae_sent} = [@_];
		1076	(delete $cv->{_ae_cb})->($cv) if $cv->{_ae_cb};
		1077	$cv->_send;
		1078	}
		1079
		1080	sub croak {
		1081	$_[0]{_ae_croak} = $_[1];
		1082	$_[0]->send;
		1083	}
		1084
		1085	sub ready {
		1086	$_[0]{_ae_sent}
		1087	}
		1088
		1089	sub _wait {
		1090	AnyEvent->one_event while !$_[0]{_ae_sent};
		1091	}
		1092
		1093	sub recv {
		1094	$_[0]->_wait;
		1095
		1096	Carp::croak $_[0]{_ae_croak} if $_[0]{_ae_croak};
		1097	wantarray ? @{ $_[0]{_ae_sent} } : $_[0]{_ae_sent}[0]
		1098	}
		1099
		1100	sub cb {
		1101	$_[0]{_ae_cb} = $_[1] if @_ > 1;
		1102	$_[0]{_ae_cb}
		1103	}
		1104
		1105	sub begin {
		1106	++$_[0]{_ae_counter};
		1107	$_[0]{_ae_end_cb} = $_[1] if @_ > 1;
		1108	}
		1109
		1110	sub end {
		1111	return if --$_[0]{_ae_counter};
		1112	&{ $_[0]{_ae_end_cb} \|\| sub { $_[0]->send } };
		1113	}
		1114
		1115	# undocumented/compatibility with pre-3.4
		1116	*broadcast = \&send;
		1117	*wait = \&_wait;
732		1118
733	=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE	1119	=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE
734		1120
735	This is an advanced topic that you do not normally need to use AnyEvent in	1121	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	1122	a module. This section is only of use to event loop authors who want to
…		…
793	model it chooses.	1179	model it chooses.
794		1180
795	=item C<PERL_ANYEVENT_MODEL>	1181	=item C<PERL_ANYEVENT_MODEL>
796		1182
797	This can be used to specify the event model to be used by AnyEvent, before	1183	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	1184	auto detection and -probing kicks in. It must be a string consisting
799	entirely of ASCII letters. The string C<AnyEvent::Impl::> gets prepended	1185	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,	1186	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	1187	used as event model. If it fails to load AnyEvent will proceed with
802	autodetection and -probing.	1188	auto detection and -probing.
803		1189
804	This functionality might change in future versions.	1190	This functionality might change in future versions.
805		1191
806	For example, to force the pure perl model (L<AnyEvent::Impl::Perl>) you	1192	For example, to force the pure perl model (L<AnyEvent::Impl::Perl>) you
807	could start your program like this:	1193	could start your program like this:
808		1194
809	PERL_ANYEVENT_MODEL=Perl perl ...	1195	PERL_ANYEVENT_MODEL=Perl perl ...
		1196
		1197	=item C<PERL_ANYEVENT_PROTOCOLS>
		1198
		1199	Used by both L<AnyEvent::DNS> and L<AnyEvent::Socket> to determine preferences
		1200	for IPv4 or IPv6. The default is unspecified (and might change, or be the result
		1201	of auto probing).
		1202
		1203	Must be set to a comma-separated list of protocols or address families,
		1204	current supported: C<ipv4> and C<ipv6>. Only protocols mentioned will be
		1205	used, and preference will be given to protocols mentioned earlier in the
		1206	list.
		1207
		1208	This variable can effectively be used for denial-of-service attacks
		1209	against local programs (e.g. when setuid), although the impact is likely
		1210	small, as the program has to handle connection errors already-
		1211
		1212	Examples: C<PERL_ANYEVENT_PROTOCOLS=ipv4,ipv6> - prefer IPv4 over IPv6,
		1213	but support both and try to use both. C<PERL_ANYEVENT_PROTOCOLS=ipv4>
		1214	- only support IPv4, never try to resolve or contact IPv6
		1215	addresses. C<PERL_ANYEVENT_PROTOCOLS=ipv6,ipv4> support either IPv4 or
		1216	IPv6, but prefer IPv6 over IPv4.
		1217
		1218	=item C<PERL_ANYEVENT_EDNS0>
		1219
		1220	Used by L<AnyEvent::DNS> to decide whether to use the EDNS0 extension
		1221	for DNS. This extension is generally useful to reduce DNS traffic, but
		1222	some (broken) firewalls drop such DNS packets, which is why it is off by
		1223	default.
		1224
		1225	Setting this variable to C<1> will cause L<AnyEvent::DNS> to announce
		1226	EDNS0 in its DNS requests.
		1227
		1228	=item C<PERL_ANYEVENT_MAX_FORKS>
		1229
		1230	The maximum number of child processes that C<AnyEvent::Util::fork_call>
		1231	will create in parallel.
810		1232
811	=back	1233	=back
812		1234
813	=head1 EXAMPLE PROGRAM	1235	=head1 EXAMPLE PROGRAM
814		1236
…		…
825	poll => 'r',	1247	poll => 'r',
826	cb => sub {	1248	cb => sub {
827	warn "io event <$_[0]>\n"; # will always output <r>	1249	warn "io event <$_[0]>\n"; # will always output <r>
828	chomp (my $input = <STDIN>); # read a line	1250	chomp (my $input = <STDIN>); # read a line
829	warn "read: $input\n"; # output what has been read	1251	warn "read: $input\n"; # output what has been read
830	$cv->broadcast if $input =~ /^q/i; # quit program if /^q/i	1252	$cv->send if $input =~ /^q/i; # quit program if /^q/i
831	},	1253	},
832	);	1254	);
833		1255
834	my $time_watcher; # can only be used once	1256	my $time_watcher; # can only be used once
835		1257
…		…
840	});	1262	});
841	}	1263	}
842		1264
843	new_timer; # create first timer	1265	new_timer; # create first timer
844		1266
845	$cv->wait; # wait until user enters /^q/i	1267	$cv->recv; # wait until user enters /^q/i
846		1268
847	=head1 REAL-WORLD EXAMPLE	1269	=head1 REAL-WORLD EXAMPLE
848		1270
849	Consider the L<Net::FCP> module. It features (among others) the following	1271	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:	1272	API calls, which are to freenet what HTTP GET requests are to http:
…		…
900	syswrite $txn->{fh}, $txn->{request}	1322	syswrite $txn->{fh}, $txn->{request}
901	or die "connection or write error";	1323	or die "connection or write error";
902	$txn->{w} = AnyEvent->io (fh => $txn->{fh}, poll => 'r', cb => sub { $txn->fh_ready_r });	1324	$txn->{w} = AnyEvent->io (fh => $txn->{fh}, poll => 'r', cb => sub { $txn->fh_ready_r });
903		1325
904	Again, C<fh_ready_r> waits till all data has arrived, and then stores the	1326	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:	1327	result and signals any possible waiters that the request has finished:
906		1328
907	sysread $txn->{fh}, $txn->{buf}, length $txn->{$buf};	1329	sysread $txn->{fh}, $txn->{buf}, length $txn->{$buf};
908		1330
909	if (end-of-file or data complete) {	1331	if (end-of-file or data complete) {
910	$txn->{result} = $txn->{buf};	1332	$txn->{result} = $txn->{buf};
911	$txn->{finished}->broadcast;	1333	$txn->{finished}->send;
912	$txb->{cb}->($txn) of $txn->{cb}; # also call callback	1334	$txb->{cb}->($txn) of $txn->{cb}; # also call callback
913	}	1335	}
914		1336
915	The C<result> method, finally, just waits for the finished signal (if the	1337	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	1338	request was already finished, it doesn't wait, of course, and returns the
917	data:	1339	data:
918		1340
919	$txn->{finished}->wait;	1341	$txn->{finished}->recv;
920	return $txn->{result};	1342	return $txn->{result};
921		1343
922	The actual code goes further and collects all errors (C<die>s, exceptions)	1344	The actual code goes further and collects all errors (C<die>s, exceptions)
923	that occured during request processing. The C<result> method detects	1345	that occurred during request processing. The C<result> method detects
924	whether an exception as thrown (it is stored inside the $txn object)	1346	whether an exception as thrown (it is stored inside the $txn object)
925	and just throws the exception, which means connection errors and other	1347	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	1348	problems get reported tot he code that tries to use the result, not in a
927	random callback.	1349	random callback.
928		1350
…		…
959		1381
960	my $quit = AnyEvent->condvar;	1382	my $quit = AnyEvent->condvar;
961		1383
962	$fcp->txn_client_get ($url)->cb (sub {	1384	$fcp->txn_client_get ($url)->cb (sub {
963	...	1385	...
964	$quit->broadcast;	1386	$quit->send;
965	});	1387	});
966		1388
967	$quit->wait;	1389	$quit->recv;
968		1390
969		1391
970	=head1 BENCHMARKS	1392	=head1 BENCHMARKS
971		1393
972	To give you an idea of the performance and overheads that AnyEvent adds	1394	To give you an idea of the performance and overheads that AnyEvent adds
…		…
974	of various event loops I prepared some benchmarks.	1396	of various event loops I prepared some benchmarks.
975		1397
976	=head2 BENCHMARKING ANYEVENT OVERHEAD	1398	=head2 BENCHMARKING ANYEVENT OVERHEAD
977		1399
978	Here is a benchmark of various supported event models used natively and	1400	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	1401	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,	1402	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.	1403	which it is), lets them fire exactly once and destroys them again.
982		1404
983	Source code for this benchmark is found as F<eg/bench> in the AnyEvent	1405	Source code for this benchmark is found as F<eg/bench> in the AnyEvent
984	distribution.	1406	distribution.
…		…
1001	all watchers, to avoid adding memory overhead. That means closure creation	1423	all watchers, to avoid adding memory overhead. That means closure creation
1002	and memory usage is not included in the figures.	1424	and memory usage is not included in the figures.
1003		1425
1004	I<invoke> is the time, in microseconds, used to invoke a simple	1426	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	1427	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	1428	invoked "watcher" times, it would C<< ->send >> a condvar once to
1007	signal the end of this phase.	1429	signal the end of this phase.
1008		1430
1009	I<destroy> is the time, in microseconds, that it takes to destroy a single	1431	I<destroy> is the time, in microseconds, that it takes to destroy a single
1010	watcher.	1432	watcher.
1011		1433
…		…
1107		1529
1108	=back	1530	=back
1109		1531
1110	=head2 BENCHMARKING THE LARGE SERVER CASE	1532	=head2 BENCHMARKING THE LARGE SERVER CASE
1111		1533
1112	This benchmark atcually benchmarks the event loop itself. It works by	1534	This benchmark actually benchmarks the event loop itself. It works by
1113	creating a number of "servers": each server consists of a socketpair, a	1535	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	1536	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	1537	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".	1538	watcher reads a byte it will write that byte to a random other "server".
1117		1539
1118	The effect is that there will be a lot of I/O watchers, only part of which	1540	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	1541	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	1542	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	1543	timeout is reset each time something is read because that reflects how
1122	most timeouts work (and puts extra pressure on the event loops).	1544	most timeouts work (and puts extra pressure on the event loops).
1123		1545
1124	In this benchmark, we use 10000 socketpairs (20000 sockets), of which 100	1546	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	1547	(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.	1548	connections, most of which are idle at any one point in time.
1127		1549
1128	Source code for this benchmark is found as F<eg/bench2> in the AnyEvent	1550	Source code for this benchmark is found as F<eg/bench2> in the AnyEvent
1129	distribution.	1551	distribution.
…		…
1131	=head3 Explanation of the columns	1553	=head3 Explanation of the columns
1132		1554
1133	I<sockets> is the number of sockets, and twice the number of "servers" (as	1555	I<sockets> is the number of sockets, and twice the number of "servers" (as
1134	each server has a read and write socket end).	1556	each server has a read and write socket end).
1135		1557
1136	I<create> is the time it takes to create a socketpair (which is	1558	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.	1559	nontrivial) and two watchers: an I/O watcher and a timeout watcher.
1138		1560
1139	I<request>, the most important value, is the time it takes to handle a	1561	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	1562	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	1563	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	1636	speed most when you have lots of watchers, not when you only have a few of
1215	them).	1637	them).
1216		1638
1217	EV is again fastest.	1639	EV is again fastest.
1218		1640
1219	Perl again comes second. It is noticably faster than the C-based event	1641	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	1642	loops Event and Glib, although the difference is too small to really
1221	matter.	1643	matter.
1222		1644
1223	POE also performs much better in this case, but is is still far behind the	1645	POE also performs much better in this case, but is is still far behind the
1224	others.	1646	others.
…		…
1253	specified in the variable.	1675	specified in the variable.
1254		1676
1255	You can make AnyEvent completely ignore this variable by deleting it	1677	You can make AnyEvent completely ignore this variable by deleting it
1256	before the first watcher gets created, e.g. with a C<BEGIN> block:	1678	before the first watcher gets created, e.g. with a C<BEGIN> block:
1257		1679
1258	BEGIN { delete $ENV{PERL_ANYEVENT_MODEL} }	1680	BEGIN { delete $ENV{PERL_ANYEVENT_MODEL} }
1259		1681
1260	use AnyEvent;	1682	use AnyEvent;
		1683
		1684	Similar considerations apply to $ENV{PERL_ANYEVENT_VERBOSE}, as that can
		1685	be used to probe what backend is used and gain other information (which is
		1686	probably even less useful to an attacker than PERL_ANYEVENT_MODEL).
		1687
		1688
		1689	=head1 BUGS
		1690
		1691	Perl 5.8 has numerous memleaks that sometimes hit this module and are hard
		1692	to work around. If you suffer from memleaks, first upgrade to Perl 5.10
		1693	and check wether the leaks still show up. (Perl 5.10.0 has other annoying
		1694	mamleaks, such as leaking on C<map> and C<grep> but it is usually not as
		1695	pronounced).
1261		1696
1262		1697
1263	=head1 SEE ALSO	1698	=head1 SEE ALSO
1264		1699
1265	Event modules: L<Coro::EV>, L<EV>, L<EV::Glib>, L<Glib::EV>,	1700	Utility functions: L<AnyEvent::Util>.
1266	L<Coro::Event>, L<Event>, L<Glib::Event>, L<Glib>, L<Coro>, L<Tk>,	1701
		1702	Event modules: L<EV>, L<EV::Glib>, L<Glib::EV>, L<Event>, L<Glib::Event>,
1267	L<Event::Lib>, L<Qt>, L<POE>.	1703	L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>.
1268		1704
1269	Implementations: L<AnyEvent::Impl::CoroEV>, L<AnyEvent::Impl::EV>,	1705	Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>,
1270	L<AnyEvent::Impl::CoroEvent>, L<AnyEvent::Impl::Event>, L<AnyEvent::Impl::Glib>,	1706	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>,	1707	L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>,
1272	L<AnyEvent::Impl::Qt>, L<AnyEvent::Impl::POE>.	1708	L<AnyEvent::Impl::POE>.
1273		1709
		1710	Non-blocking file handles, sockets, TCP clients and
		1711	servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>.
		1712
		1713	Asynchronous DNS: L<AnyEvent::DNS>.
		1714
		1715	Coroutine support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>, L<Coro::Event>,
		1716
1274	Nontrivial usage examples: L<Net::FCP>, L<Net::XMPP2>.	1717	Nontrivial usage examples: L<Net::FCP>, L<Net::XMPP2>, L<AnyEvent::DNS>.
1275		1718
1276		1719
1277	=head1 AUTHOR	1720	=head1 AUTHOR
1278		1721
1279	Marc Lehmann <schmorp@schmorp.de>	1722	Marc Lehmann <schmorp@schmorp.de>
1280	http://home.schmorp.de/	1723	http://home.schmorp.de/
1281		1724
1282	=cut	1725	=cut
1283		1726
1284	1	1727	1
1285		1728

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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 1.164 by root, Tue Jul 8 19:50:25 2008 UTC

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Revision 1.104 by root, Wed Apr 30 11:40:22 2008 UTC vs.
Revision 1.164 by root, Tue Jul 8 19:50:25 2008 UTC