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

Comparing AnyEvent/lib/AnyEvent.pm (file contents):
Revision 1.113 by root, Sat May 10 20:30:35 2008 UTC vs.
Revision 1.173 by root, Mon Jul 21 03:47:22 2008 UTC

…		…
6		6
7	=head1 SYNOPSIS	7	=head1 SYNOPSIS
8		8
9	use AnyEvent;	9	use AnyEvent;
10		10
11	my $w = AnyEvent->io (fh => $fh, poll => "r\|w", cb => sub {	11	my $w = AnyEvent->io (fh => $fh, poll => "r\|w", cb => sub { ... });
		12
		13	my $w = AnyEvent->timer (after => $seconds, cb => sub { ... });
		14	my $w = AnyEvent->timer (after => $seconds, interval => $seconds, cb => ...
		15
		16	print AnyEvent->now; # prints current event loop time
		17	print AnyEvent->time; # think Time::HiRes::time or simply CORE::time.
		18
		19	my $w = AnyEvent->signal (signal => "TERM", cb => sub { ... });
		20
		21	my $w = AnyEvent->child (pid => $pid, cb => sub {
		22	my ($pid, $status) = @_;
12	...	23	...
13	});	24	});
14		25
15	my $w = AnyEvent->timer (after => $seconds, cb => sub {
16	...
17	});
18
19	my $w = AnyEvent->condvar; # stores whether a condition was flagged	26	my $w = AnyEvent->condvar; # stores whether a condition was flagged
		27	$w->send; # wake up current and all future recv's
20	$w->wait; # enters "main loop" till $condvar gets ->send	28	$w->recv; # enters "main loop" till $condvar gets ->send
21	$w->send; # wake up current and all future wait's	29	# use a condvar in callback mode:
		30	$w->cb (sub { $_[0]->recv });
		31
		32	=head1 INTRODUCTION/TUTORIAL
		33
		34	This manpage is mainly a reference manual. If you are interested
		35	in a tutorial or some gentle introduction, have a look at the
		36	L<AnyEvent::Intro> manpage.
22		37
23	=head1 WHY YOU SHOULD USE THIS MODULE (OR NOT)	38	=head1 WHY YOU SHOULD USE THIS MODULE (OR NOT)
24		39
25	Glib, POE, IO::Async, Event... CPAN offers event models by the dozen	40	Glib, POE, IO::Async, Event... CPAN offers event models by the dozen
26	nowadays. So what is different about AnyEvent?	41	nowadays. So what is different about AnyEvent?
27		42
28	Executive Summary: AnyEvent is I<compatible>, AnyEvent is I<free of	43	Executive Summary: AnyEvent is I<compatible>, AnyEvent is I<free of
29	policy> and AnyEvent is I<small and efficient>.	44	policy> and AnyEvent is I<small and efficient>.
30		45
31	First and foremost, I<AnyEvent is not an event model> itself, it only	46	First and foremost, I<AnyEvent is not an event model> itself, it only
32	interfaces to whatever event model the main program happens to use in a	47	interfaces to whatever event model the main program happens to use, in a
33	pragmatic way. For event models and certain classes of immortals alike,	48	pragmatic way. For event models and certain classes of immortals alike,
34	the statement "there can only be one" is a bitter reality: In general,	49	the statement "there can only be one" is a bitter reality: In general,
35	only one event loop can be active at the same time in a process. AnyEvent	50	only one event loop can be active at the same time in a process. AnyEvent
36	helps hiding the differences between those event loops.	51	cannot change this, but it can hide the differences between those event
		52	loops.
37		53
38	The goal of AnyEvent is to offer module authors the ability to do event	54	The goal of AnyEvent is to offer module authors the ability to do event
39	programming (waiting for I/O or timer events) without subscribing to a	55	programming (waiting for I/O or timer events) without subscribing to a
40	religion, a way of living, and most importantly: without forcing your	56	religion, a way of living, and most importantly: without forcing your
41	module users into the same thing by forcing them to use the same event	57	module users into the same thing by forcing them to use the same event
42	model you use.	58	model you use.
43		59
44	For modules like POE or IO::Async (which is a total misnomer as it is	60	For modules like POE or IO::Async (which is a total misnomer as it is
45	actually doing all I/O I<synchronously>...), using them in your module is	61	actually doing all I/O I<synchronously>...), using them in your module is
46	like joining a cult: After you joined, you are dependent on them and you	62	like joining a cult: After you joined, you are dependent on them and you
47	cannot use anything else, as it is simply incompatible to everything that	63	cannot use anything else, as they are simply incompatible to everything
48	isn't itself. What's worse, all the potential users of your module are	64	that isn't them. What's worse, all the potential users of your
49	I<also> forced to use the same event loop you use.	65	module are I<also> forced to use the same event loop you use.
50		66
51	AnyEvent is different: AnyEvent + POE works fine. AnyEvent + Glib works	67	AnyEvent is different: AnyEvent + POE works fine. AnyEvent + Glib works
52	fine. AnyEvent + Tk works fine etc. etc. but none of these work together	68	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	69	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,	70	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	71	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	72	event models it supports (including stuff like IO::Async, as long as those
57	as those use one of the supported event loops. It is trivial to add new	73	use one of the supported event loops. It is trivial to add new event loops
58	event loops to AnyEvent, too, so it is future-proof).	74	to AnyEvent, too, so it is future-proof).
59		75
60	In addition to being free of having to use I<the one and only true event	76	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	77	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	78	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	79	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	80	offering the functionality that is necessary, in as thin as a wrapper as
65	technically possible.	81	technically possible.
66		82
		83	Of course, AnyEvent comes with a big (and fully optional!) toolbox
		84	of useful functionality, such as an asynchronous DNS resolver, 100%
		85	non-blocking connects (even with TLS/SSL, IPv6 and on broken platforms
		86	such as Windows) and lots of real-world knowledge and workarounds for
		87	platform bugs and differences.
		88
67	Of course, if you want lots of policy (this can arguably be somewhat	89	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	90	useful) and you want to force your users to use the one and only event
69	model, you should I<not> use this module.	91	model, you should I<not> use this module.
70		92
71	=head1 DESCRIPTION	93	=head1 DESCRIPTION
72		94
…		…
102	starts using it, all bets are off. Maybe you should tell their authors to	124	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...	125	use AnyEvent so their modules work together with others seamlessly...
104		126
105	The pure-perl implementation of AnyEvent is called	127	The pure-perl implementation of AnyEvent is called
106	C<AnyEvent::Impl::Perl>. Like other event modules you can load it	128	C<AnyEvent::Impl::Perl>. Like other event modules you can load it
107	explicitly.	129	explicitly and enjoy the high availability of that event loop :)
108		130
109	=head1 WATCHERS	131	=head1 WATCHERS
110		132
111	AnyEvent has the central concept of a I<watcher>, which is an object that	133	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	134	stores relevant data for each kind of event you are waiting for, such as
113	the callback to call, the filehandle to watch, etc.	135	the callback to call, the file handle to watch, etc.
114		136
115	These watchers are normal Perl objects with normal Perl lifetime. After	137	These watchers are normal Perl objects with normal Perl lifetime. After
116	creating a watcher it will immediately "watch" for events and invoke the	138	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	139	callback when the event occurs (of course, only when the event model
118	is in control).	140	is in control).
…		…
126	Many watchers either are used with "recursion" (repeating timers for	148	Many watchers either are used with "recursion" (repeating timers for
127	example), or need to refer to their watcher object in other ways.	149	example), or need to refer to their watcher object in other ways.
128		150
129	An any way to achieve that is this pattern:	151	An any way to achieve that is this pattern:
130		152
131	my $w; $w = AnyEvent->type (arg => value ..., cb => sub {	153	my $w; $w = AnyEvent->type (arg => value ..., cb => sub {
132	# you can use $w here, for example to undef it	154	# you can use $w here, for example to undef it
133	undef $w;	155	undef $w;
134	});	156	});
135		157
136	Note that C<my $w; $w => combination. This is necessary because in Perl,	158	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	159	my variables are only visible after the statement in which they are
138	declared.	160	declared.
139		161
140	=head2 I/O WATCHERS	162	=head2 I/O WATCHERS
141		163
142	You can create an I/O watcher by calling the C<< AnyEvent->io >> method	164	You can create an I/O watcher by calling the C<< AnyEvent->io >> method
143	with the following mandatory key-value pairs as arguments:	165	with the following mandatory key-value pairs as arguments:
144		166
145	C<fh> the Perl I<file handle> (I<not> file descriptor) to watch	167	C<fh> the Perl I<file handle> (I<not> file descriptor) to watch for events
146	for events. C<poll> must be a string that is either C<r> or C<w>,	168	(AnyEvent might or might not keep a reference to this file handle). C<poll>
147	which creates a watcher waiting for "r"eadable or "w"ritable events,	169	must be a string that is either C<r> or C<w>, which creates a watcher
148	respectively. C<cb> is the callback to invoke each time the file handle	170	waiting for "r"eadable or "w"ritable events, respectively. C<cb> is the
149	becomes ready.	171	callback to invoke each time the file handle becomes ready.
150		172
151	Although the callback might get passed parameters, their value and	173	Although the callback might get passed parameters, their value and
152	presence is undefined and you cannot rely on them. Portable AnyEvent	174	presence is undefined and you cannot rely on them. Portable AnyEvent
153	callbacks cannot use arguments passed to I/O watcher callbacks.	175	callbacks cannot use arguments passed to I/O watcher callbacks.
154		176
…		…
158		180
159	Some event loops issue spurious readyness notifications, so you should	181	Some event loops issue spurious readyness notifications, so you should
160	always use non-blocking calls when reading/writing from/to your file	182	always use non-blocking calls when reading/writing from/to your file
161	handles.	183	handles.
162		184
163	Example:
164
165	# wait for readability of STDIN, then read a line and disable the watcher	185	Example: wait for readability of STDIN, then read a line and disable the
		186	watcher.
		187
166	my $w; $w = AnyEvent->io (fh => \*STDIN, poll => 'r', cb => sub {	188	my $w; $w = AnyEvent->io (fh => \*STDIN, poll => 'r', cb => sub {
167	chomp (my $input = <STDIN>);	189	chomp (my $input = <STDIN>);
168	warn "read: $input\n";	190	warn "read: $input\n";
169	undef $w;	191	undef $w;
170	});	192	});
…		…
180		202
181	Although the callback might get passed parameters, their value and	203	Although the callback might get passed parameters, their value and
182	presence is undefined and you cannot rely on them. Portable AnyEvent	204	presence is undefined and you cannot rely on them. Portable AnyEvent
183	callbacks cannot use arguments passed to time watcher callbacks.	205	callbacks cannot use arguments passed to time watcher callbacks.
184		206
185	The timer callback will be invoked at most once: if you want a repeating	207	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	208	parameter, C<interval>, as a strictly positive number (> 0), then the
187	and Glib).	209	callback will be invoked regularly at that interval (in fractional
		210	seconds) after the first invocation. If C<interval> is specified with a
		211	false value, then it is treated as if it were missing.
188		212
189	Example:	213	The callback will be rescheduled before invoking the callback, but no
		214	attempt is done to avoid timer drift in most backends, so the interval is
		215	only approximate.
190		216
191	# fire an event after 7.7 seconds	217	Example: fire an event after 7.7 seconds.
		218
192	my $w = AnyEvent->timer (after => 7.7, cb => sub {	219	my $w = AnyEvent->timer (after => 7.7, cb => sub {
193	warn "timeout\n";	220	warn "timeout\n";
194	});	221	});
195		222
196	# to cancel the timer:	223	# to cancel the timer:
197	undef $w;	224	undef $w;
198		225
199	Example 2:
200
201	# fire an event after 0.5 seconds, then roughly every second	226	Example 2: fire an event after 0.5 seconds, then roughly every second.
202	my $w;
203		227
204	my $cb = sub {
205	# cancel the old timer while creating a new one
206	$w = AnyEvent->timer (after => 1, cb => $cb);	228	my $w = AnyEvent->timer (after => 0.5, interval => 1, cb => sub {
		229	warn "timeout\n";
207	};	230	};
208
209	# start the "loop" by creating the first watcher
210	$w = AnyEvent->timer (after => 0.5, cb => $cb);
211		231
212	=head3 TIMING ISSUES	232	=head3 TIMING ISSUES
213		233
214	There are two ways to handle timers: based on real time (relative, "fire	234	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	235	in 10 seconds") and based on wallclock time (absolute, "fire at 12
…		…
227	timers.	247	timers.
228		248
229	AnyEvent always prefers relative timers, if available, matching the	249	AnyEvent always prefers relative timers, if available, matching the
230	AnyEvent API.	250	AnyEvent API.
231		251
		252	AnyEvent has two additional methods that return the "current time":
		253
		254	=over 4
		255
		256	=item AnyEvent->time
		257
		258	This returns the "current wallclock time" as a fractional number of
		259	seconds since the Epoch (the same thing as C<time> or C<Time::HiRes::time>
		260	return, and the result is guaranteed to be compatible with those).
		261
		262	It progresses independently of any event loop processing, i.e. each call
		263	will check the system clock, which usually gets updated frequently.
		264
		265	=item AnyEvent->now
		266
		267	This also returns the "current wallclock time", but unlike C<time>, above,
		268	this value might change only once per event loop iteration, depending on
		269	the event loop (most return the same time as C<time>, above). This is the
		270	time that AnyEvent's timers get scheduled against.
		271
		272	I<In almost all cases (in all cases if you don't care), this is the
		273	function to call when you want to know the current time.>
		274
		275	This function is also often faster then C<< AnyEvent->time >>, and
		276	thus the preferred method if you want some timestamp (for example,
		277	L<AnyEvent::Handle> uses this to update it's activity timeouts).
		278
		279	The rest of this section is only of relevance if you try to be very exact
		280	with your timing, you can skip it without bad conscience.
		281
		282	For a practical example of when these times differ, consider L<Event::Lib>
		283	and L<EV> and the following set-up:
		284
		285	The event loop is running and has just invoked one of your callback at
		286	time=500 (assume no other callbacks delay processing). In your callback,
		287	you wait a second by executing C<sleep 1> (blocking the process for a
		288	second) and then (at time=501) you create a relative timer that fires
		289	after three seconds.
		290
		291	With L<Event::Lib>, C<< AnyEvent->time >> and C<< AnyEvent->now >> will
		292	both return C<501>, because that is the current time, and the timer will
		293	be scheduled to fire at time=504 (C<501> + C<3>).
		294
		295	With L<EV>, C<< AnyEvent->time >> returns C<501> (as that is the current
		296	time), but C<< AnyEvent->now >> returns C<500>, as that is the time the
		297	last event processing phase started. With L<EV>, your timer gets scheduled
		298	to run at time=503 (C<500> + C<3>).
		299
		300	In one sense, L<Event::Lib> is more exact, as it uses the current time
		301	regardless of any delays introduced by event processing. However, most
		302	callbacks do not expect large delays in processing, so this causes a
		303	higher drift (and a lot more system calls to get the current time).
		304
		305	In another sense, L<EV> is more exact, as your timer will be scheduled at
		306	the same time, regardless of how long event processing actually took.
		307
		308	In either case, if you care (and in most cases, you don't), then you
		309	can get whatever behaviour you want with any event loop, by taking the
		310	difference between C<< AnyEvent->time >> and C<< AnyEvent->now >> into
		311	account.
		312
		313	=back
		314
232	=head2 SIGNAL WATCHERS	315	=head2 SIGNAL WATCHERS
233		316
234	You can watch for signals using a signal watcher, C<signal> is the signal	317	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	318	I<name> in uppercase and without any C<SIG> prefix, C<cb> is the Perl
236	be invoked whenever a signal occurs.	319	callback to be invoked whenever a signal occurs.
237		320
238	Although the callback might get passed parameters, their value and	321	Although the callback might get passed parameters, their value and
239	presence is undefined and you cannot rely on them. Portable AnyEvent	322	presence is undefined and you cannot rely on them. Portable AnyEvent
240	callbacks cannot use arguments passed to signal watcher callbacks.	323	callbacks cannot use arguments passed to signal watcher callbacks.
241		324
242	Multiple signal occurances can be clumped together into one callback	325	Multiple signal occurrences can be clumped together into one callback
243	invocation, and callback invocation will be synchronous. synchronous means	326	invocation, and callback invocation will be synchronous. Synchronous means
244	that it might take a while until the signal gets handled by the process,	327	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.	328	but it is guaranteed not to interrupt any other callbacks.
246		329
247	The main advantage of using these watchers is that you can share a signal	330	The main advantage of using these watchers is that you can share a signal
248	between multiple watchers.	331	between multiple watchers.
249		332
250	This watcher might use C<%SIG>, so programs overwriting those signals	333	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	360	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>).	361	C<fork> the child (alternatively, you can call C<AnyEvent::detect>).
279		362
280	Example: fork a process and wait for it	363	Example: fork a process and wait for it
281		364
282	my $done = AnyEvent->condvar;	365	my $done = AnyEvent->condvar;
283		366
284	AnyEvent::detect; # force event module to be initialised
285
286	my $pid = fork or exit 5;	367	my $pid = fork or exit 5;
287		368
288	my $w = AnyEvent->child (	369	my $w = AnyEvent->child (
289	pid => $pid,	370	pid => $pid,
290	cb => sub {	371	cb => sub {
291	my ($pid, $status) = @_;	372	my ($pid, $status) = @_;
292	warn "pid $pid exited with status $status";	373	warn "pid $pid exited with status $status";
293	$done->send;	374	$done->send;
294	},	375	},
295	);	376	);
296		377
297	# do something else, then wait for process exit	378	# do something else, then wait for process exit
298	$done->wait;	379	$done->recv;
299		380
300	=head2 CONDITION VARIABLES	381	=head2 CONDITION VARIABLES
301		382
302	If you are familiar with some event loops you will know that all of them	383	If you are familiar with some event loops you will know that all of them
303	require you to run some blocking "loop", "run" or similar function that	384	require you to run some blocking "loop", "run" or similar function that
…		…
308		389
309	The instrument to do that is called a "condition variable", so called	390	The instrument to do that is called a "condition variable", so called
310	because they represent a condition that must become true.	391	because they represent a condition that must become true.
311		392
312	Condition variables can be created by calling the C<< AnyEvent->condvar	393	Condition variables can be created by calling the C<< AnyEvent->condvar
		394
313	>> method, usually without arguments. The only argument pair allowed is	395	>> method, usually without arguments. The only argument pair allowed is
		396
314	C<cb>, which specifies a callback to be called when the condition variable	397	C<cb>, which specifies a callback to be called when the condition variable
315	becomes true.	398	becomes true, with the condition variable as the first argument (but not
		399	the results).
316		400
317	After creation, the conditon variable is "false" until it becomes "true"	401	After creation, the condition variable is "false" until it becomes "true"
318	by calling the C<send> method.	402	by calling the C<send> method (or calling the condition variable as if it
		403	were a callback, read about the caveats in the description for the C<<
		404	->send >> method).
319		405
320	Condition variables are similar to callbacks, except that you can	406	Condition variables are similar to callbacks, except that you can
321	optionally wait for them. They can also be called merge points - points	407	optionally wait for them. They can also be called merge points - points
322	in time where multiple outstandign events have been processed. And yet	408	in time where multiple outstanding events have been processed. And yet
323	another way to call them is transations - each condition variable can be	409	another way to call them is transactions - each condition variable can be
324	used to represent a transaction, which finishes at some point and delivers	410	used to represent a transaction, which finishes at some point and delivers
325	a result.	411	a result.
326		412
327	Condition variables are very useful to signal that something has finished,	413	Condition variables are very useful to signal that something has finished,
328	for example, if you write a module that does asynchronous http requests,	414	for example, if you write a module that does asynchronous http requests,
329	then a condition variable would be the ideal candidate to signal the	415	then a condition variable would be the ideal candidate to signal the
330	availability of results. The user can either act when the callback is	416	availability of results. The user can either act when the callback is
331	called or can synchronously C<< ->wait >> for the results.	417	called or can synchronously C<< ->recv >> for the results.
332		418
333	You can also use them to simulate traditional event loops - for example,	419	You can also use them to simulate traditional event loops - for example,
334	you can block your main program until an event occurs - for example, you	420	you can block your main program until an event occurs - for example, you
335	could C<< ->wait >> in your main program until the user clicks the Quit	421	could C<< ->recv >> in your main program until the user clicks the Quit
336	button of your app, which would C<< ->send >> the "quit" event.	422	button of your app, which would C<< ->send >> the "quit" event.
337		423
338	Note that condition variables recurse into the event loop - if you have	424	Note that condition variables recurse into the event loop - if you have
339	two pieces of code that call C<< ->wait >> in a round-robbin fashion, you	425	two pieces of code that call C<< ->recv >> in a round-robin fashion, you
340	lose. Therefore, condition variables are good to export to your caller, but	426	lose. Therefore, condition variables are good to export to your caller, but
341	you should avoid making a blocking wait yourself, at least in callbacks,	427	you should avoid making a blocking wait yourself, at least in callbacks,
342	as this asks for trouble.	428	as this asks for trouble.
343		429
344	Condition variables are represented by hash refs in perl, and the keys	430	Condition variables are represented by hash refs in perl, and the keys
…		…
349		435
350	There are two "sides" to a condition variable - the "producer side" which	436	There are two "sides" to a condition variable - the "producer side" which
351	eventually calls C<< -> send >>, and the "consumer side", which waits	437	eventually calls C<< -> send >>, and the "consumer side", which waits
352	for the send to occur.	438	for the send to occur.
353		439
354	Example:	440	Example: wait for a timer.
355		441
356	# wait till the result is ready	442	# wait till the result is ready
357	my $result_ready = AnyEvent->condvar;	443	my $result_ready = AnyEvent->condvar;
358		444
359	# do something such as adding a timer	445	# do something such as adding a timer
…		…
365	cb => sub { $result_ready->send },	451	cb => sub { $result_ready->send },
366	);	452	);
367		453
368	# this "blocks" (while handling events) till the callback	454	# this "blocks" (while handling events) till the callback
369	# calls send	455	# calls send
370	$result_ready->wait;	456	$result_ready->recv;
		457
		458	Example: wait for a timer, but take advantage of the fact that
		459	condition variables are also code references.
		460
		461	my $done = AnyEvent->condvar;
		462	my $delay = AnyEvent->timer (after => 5, cb => $done);
		463	$done->recv;
		464
		465	Example: Imagine an API that returns a condvar and doesn't support
		466	callbacks. This is how you make a synchronous call, for example from
		467	the main program:
		468
		469	use AnyEvent::CouchDB;
		470
		471	...
		472
		473	my @info = $couchdb->info->recv;
		474
		475	And this is how you would just ste a callback to be called whenever the
		476	results are available:
		477
		478	$couchdb->info->cb (sub {
		479	my @info = $_[0]->recv;
		480	});
371		481
372	=head3 METHODS FOR PRODUCERS	482	=head3 METHODS FOR PRODUCERS
373		483
374	These methods should only be used by the producing side, i.e. the	484	These methods should only be used by the producing side, i.e. the
375	code/module that eventually sends the signal. Note that it is also	485	code/module that eventually sends the signal. Note that it is also
…		…
378		488
379	=over 4	489	=over 4
380		490
381	=item $cv->send (...)	491	=item $cv->send (...)
382		492
383	Flag the condition as ready - a running C<< ->wait >> and all further	493	Flag the condition as ready - a running C<< ->recv >> and all further
384	calls to C<wait> will (eventually) return after this method has been	494	calls to C<recv> will (eventually) return after this method has been
385	called. If nobody is waiting the send will be remembered.	495	called. If nobody is waiting the send will be remembered.
386		496
387	If a callback has been set on the condition variable, it is called	497	If a callback has been set on the condition variable, it is called
388	immediately from within send.	498	immediately from within send.
389		499
390	Any arguments passed to the C<send> call will be returned by all	500	Any arguments passed to the C<send> call will be returned by all
391	future C<< ->wait >> calls.	501	future C<< ->recv >> calls.
		502
		503	Condition variables are overloaded so one can call them directly
		504	(as a code reference). Calling them directly is the same as calling
		505	C<send>. Note, however, that many C-based event loops do not handle
		506	overloading, so as tempting as it may be, passing a condition variable
		507	instead of a callback does not work. Both the pure perl and EV loops
		508	support overloading, however, as well as all functions that use perl to
		509	invoke a callback (as in L<AnyEvent::Socket> and L<AnyEvent::DNS> for
		510	example).
392		511
393	=item $cv->croak ($error)	512	=item $cv->croak ($error)
394		513
395	Similar to send, but causes all call's wait C<< ->wait >> to invoke	514	Similar to send, but causes all call's to C<< ->recv >> to invoke
396	C<Carp::croak> with the given error message/object/scalar.	515	C<Carp::croak> with the given error message/object/scalar.
397		516
398	This can be used to signal any errors to the condition variable	517	This can be used to signal any errors to the condition variable
399	user/consumer.	518	user/consumer.
400		519
401	=item $cv->begin ([group callback])	520	=item $cv->begin ([group callback])
402		521
403	=item $cv->end	522	=item $cv->end
		523
		524	These two methods are EXPERIMENTAL and MIGHT CHANGE.
404		525
405	These two methods can be used to combine many transactions/events into	526	These two methods can be used to combine many transactions/events into
406	one. For example, a function that pings many hosts in parallel might want	527	one. For example, a function that pings many hosts in parallel might want
407	to use a condition variable for the whole process.	528	to use a condition variable for the whole process.
408		529
…		…
443	doesn't execute once).	564	doesn't execute once).
444		565
445	This is the general pattern when you "fan out" into multiple subrequests:	566	This is the general pattern when you "fan out" into multiple subrequests:
446	use an outer C<begin>/C<end> pair to set the callback and ensure C<end>	567	use an outer C<begin>/C<end> pair to set the callback and ensure C<end>
447	is called at least once, and then, for each subrequest you start, call	568	is called at least once, and then, for each subrequest you start, call
448	C<begin> and for eahc subrequest you finish, call C<end>.	569	C<begin> and for each subrequest you finish, call C<end>.
449		570
450	=back	571	=back
451		572
452	=head3 METHODS FOR CONSUMERS	573	=head3 METHODS FOR CONSUMERS
453		574
454	These methods should only be used by the consuming side, i.e. the	575	These methods should only be used by the consuming side, i.e. the
455	code awaits the condition.	576	code awaits the condition.
456		577
457	=over 4	578	=over 4
458		579
459	=item $cv->wait	580	=item $cv->recv
460		581
461	Wait (blocking if necessary) until the C<< ->send >> or C<< ->croak	582	Wait (blocking if necessary) until the C<< ->send >> or C<< ->croak
462	>> methods have been called on c<$cv>, while servicing other watchers	583	>> methods have been called on c<$cv>, while servicing other watchers
463	normally.	584	normally.
464		585
…		…
475	(programs might want to do that to stay interactive), so I<if you are	596	(programs might want to do that to stay interactive), so I<if you are
476	using this from a module, never require a blocking wait>, but let the	597	using this from a module, never require a blocking wait>, but let the
477	caller decide whether the call will block or not (for example, by coupling	598	caller decide whether the call will block or not (for example, by coupling
478	condition variables with some kind of request results and supporting	599	condition variables with some kind of request results and supporting
479	callbacks so the caller knows that getting the result will not block,	600	callbacks so the caller knows that getting the result will not block,
480	while still suppporting blocking waits if the caller so desires).	601	while still supporting blocking waits if the caller so desires).
481		602
482	Another reason I<never> to C<< ->wait >> in a module is that you cannot	603	Another reason I<never> to C<< ->recv >> in a module is that you cannot
483	sensibly have two C<< ->wait >>'s in parallel, as that would require	604	sensibly have two C<< ->recv >>'s in parallel, as that would require
484	multiple interpreters or coroutines/threads, none of which C<AnyEvent>	605	multiple interpreters or coroutines/threads, none of which C<AnyEvent>
485	can supply.	606	can supply.
486		607
487	The L<Coro> module, however, I<can> and I<does> supply coroutines and, in	608	The L<Coro> module, however, I<can> and I<does> supply coroutines and, in
488	fact, L<Coro::AnyEvent> replaces AnyEvent's condvars by coroutine-safe	609	fact, L<Coro::AnyEvent> replaces AnyEvent's condvars by coroutine-safe
489	versions and also integrates coroutines into AnyEvent, making blocking	610	versions and also integrates coroutines into AnyEvent, making blocking
490	C<< ->wait >> calls perfectly safe as long as they are done from another	611	C<< ->recv >> calls perfectly safe as long as they are done from another
491	coroutine (one that doesn't run the event loop).	612	coroutine (one that doesn't run the event loop).
492		613
493	You can ensure that C<< -wait >> never blocks by setting a callback and	614	You can ensure that C<< -recv >> never blocks by setting a callback and
494	only calling C<< ->wait >> from within that callback (or at a later	615	only calling C<< ->recv >> from within that callback (or at a later
495	time). This will work even when the event loop does not support blocking	616	time). This will work even when the event loop does not support blocking
496	waits otherwise.	617	waits otherwise.
497		618
498	=item $bool = $cv->ready	619	=item $bool = $cv->ready
499		620
500	Returns true when the condition is "true", i.e. whether C<send> or	621	Returns true when the condition is "true", i.e. whether C<send> or
501	C<croak> have been called.	622	C<croak> have been called.
502		623
503	=item $cb = $cv->cb ([new callback])	624	=item $cb = $cv->cb ($cb->($cv))
504		625
505	This is a mutator function that returns the callback set and optionally	626	This is a mutator function that returns the callback set and optionally
506	replaces it before doing so.	627	replaces it before doing so.
507		628
508	The callback will be called when the condition becomes "true", i.e. when	629	The callback will be called when the condition becomes "true", i.e. when
509	C<send> or C<croak> are called. Calling C<wait> inside the callback	630	C<send> or C<croak> are called, with the only argument being the condition
510	or at any later time is guaranteed not to block.	631	variable itself. Calling C<recv> inside the callback or at any later time
		632	is guaranteed not to block.
511		633
512	=back	634	=back
513		635
514	=head1 GLOBAL VARIABLES AND FUNCTIONS	636	=head1 GLOBAL VARIABLES AND FUNCTIONS
515		637
…		…
582	Be careful when you create watchers in the module body - AnyEvent will	704	Be careful when you create watchers in the module body - AnyEvent will
583	decide which event module to use as soon as the first method is called, so	705	decide which event module to use as soon as the first method is called, so
584	by calling AnyEvent in your module body you force the user of your module	706	by calling AnyEvent in your module body you force the user of your module
585	to load the event module first.	707	to load the event module first.
586		708
587	Never call C<< ->wait >> on a condition variable unless you I<know> that	709	Never call C<< ->recv >> on a condition variable unless you I<know> that
588	the C<< ->send >> method has been called on it already. This is	710	the C<< ->send >> method has been called on it already. This is
589	because it will stall the whole program, and the whole point of using	711	because it will stall the whole program, and the whole point of using
590	events is to stay interactive.	712	events is to stay interactive.
591		713
592	It is fine, however, to call C<< ->wait >> when the user of your module	714	It is fine, however, to call C<< ->recv >> when the user of your module
593	requests it (i.e. if you create a http request object ad have a method	715	requests it (i.e. if you create a http request object ad have a method
594	called C<results> that returns the results, it should call C<< ->wait >>	716	called C<results> that returns the results, it should call C<< ->recv >>
595	freely, as the user of your module knows what she is doing. always).	717	freely, as the user of your module knows what she is doing. always).
596		718
597	=head1 WHAT TO DO IN THE MAIN PROGRAM	719	=head1 WHAT TO DO IN THE MAIN PROGRAM
598		720
599	There will always be a single main program - the only place that should	721	There will always be a single main program - the only place that should
…		…
601		723
602	If it doesn't care, it can just "use AnyEvent" and use it itself, or not	724	If it doesn't care, it can just "use AnyEvent" and use it itself, or not
603	do anything special (it does not need to be event-based) and let AnyEvent	725	do anything special (it does not need to be event-based) and let AnyEvent
604	decide which implementation to chose if some module relies on it.	726	decide which implementation to chose if some module relies on it.
605		727
606	If the main program relies on a specific event model. For example, in	728	If the main program relies on a specific event model - for example, in
607	Gtk2 programs you have to rely on the Glib module. You should load the	729	Gtk2 programs you have to rely on the Glib module - you should load the
608	event module before loading AnyEvent or any module that uses it: generally	730	event module before loading AnyEvent or any module that uses it: generally
609	speaking, you should load it as early as possible. The reason is that	731	speaking, you should load it as early as possible. The reason is that
610	modules might create watchers when they are loaded, and AnyEvent will	732	modules might create watchers when they are loaded, and AnyEvent will
611	decide on the event model to use as soon as it creates watchers, and it	733	decide on the event model to use as soon as it creates watchers, and it
612	might chose the wrong one unless you load the correct one yourself.	734	might chose the wrong one unless you load the correct one yourself.
613		735
614	You can chose to use a rather inefficient pure-perl implementation by	736	You can chose to use a pure-perl implementation by loading the
615	loading the C<AnyEvent::Impl::Perl> module, which gives you similar	737	C<AnyEvent::Impl::Perl> module, which gives you similar behaviour
616	behaviour everywhere, but letting AnyEvent chose is generally better.	738	everywhere, but letting AnyEvent chose the model is generally better.
		739
		740	=head2 MAINLOOP EMULATION
		741
		742	Sometimes (often for short test scripts, or even standalone programs who
		743	only want to use AnyEvent), you do not want to run a specific event loop.
		744
		745	In that case, you can use a condition variable like this:
		746
		747	AnyEvent->condvar->recv;
		748
		749	This has the effect of entering the event loop and looping forever.
		750
		751	Note that usually your program has some exit condition, in which case
		752	it is better to use the "traditional" approach of storing a condition
		753	variable somewhere, waiting for it, and sending it when the program should
		754	exit cleanly.
		755
617		756
618	=head1 OTHER MODULES	757	=head1 OTHER MODULES
619		758
620	The following is a non-exhaustive list of additional modules that use	759	The following is a non-exhaustive list of additional modules that use
621	AnyEvent and can therefore be mixed easily with other AnyEvent modules	760	AnyEvent and can therefore be mixed easily with other AnyEvent modules
…		…
627	=item L<AnyEvent::Util>	766	=item L<AnyEvent::Util>
628		767
629	Contains various utility functions that replace often-used but blocking	768	Contains various utility functions that replace often-used but blocking
630	functions such as C<inet_aton> by event-/callback-based versions.	769	functions such as C<inet_aton> by event-/callback-based versions.
631		770
		771	=item L<AnyEvent::Socket>
		772
		773	Provides various utility functions for (internet protocol) sockets,
		774	addresses and name resolution. Also functions to create non-blocking tcp
		775	connections or tcp servers, with IPv6 and SRV record support and more.
		776
632	=item L<AnyEvent::Handle>	777	=item L<AnyEvent::Handle>
633		778
634	Provide read and write buffers and manages watchers for reads and writes.	779	Provide read and write buffers, manages watchers for reads and writes,
		780	supports raw and formatted I/O, I/O queued and fully transparent and
		781	non-blocking SSL/TLS.
		782
		783	=item L<AnyEvent::DNS>
		784
		785	Provides rich asynchronous DNS resolver capabilities.
		786
		787	=item L<AnyEvent::HTTP>
		788
		789	A simple-to-use HTTP library that is capable of making a lot of concurrent
		790	HTTP requests.
635		791
636	=item L<AnyEvent::HTTPD>	792	=item L<AnyEvent::HTTPD>
637		793
638	Provides a simple web application server framework.	794	Provides a simple web application server framework.
639		795
640	=item L<AnyEvent::DNS>
641
642	Provides asynchronous DNS resolver capabilities, beyond what
643	L<AnyEvent::Util> offers.
644
645	=item L<AnyEvent::FastPing>	796	=item L<AnyEvent::FastPing>
646		797
647	The fastest ping in the west.	798	The fastest ping in the west.
		799
		800	=item L<AnyEvent::DBI>
		801
		802	Executes L<DBI> requests asynchronously in a proxy process.
		803
		804	=item L<AnyEvent::AIO>
		805
		806	Truly asynchronous I/O, should be in the toolbox of every event
		807	programmer. AnyEvent::AIO transparently fuses L<IO::AIO> and AnyEvent
		808	together.
		809
		810	=item L<AnyEvent::BDB>
		811
		812	Truly asynchronous Berkeley DB access. AnyEvent::BDB transparently fuses
		813	L<BDB> and AnyEvent together.
		814
		815	=item L<AnyEvent::GPSD>
		816
		817	A non-blocking interface to gpsd, a daemon delivering GPS information.
		818
		819	=item L<AnyEvent::IGS>
		820
		821	A non-blocking interface to the Internet Go Server protocol (used by
		822	L<App::IGS>).
648		823
649	=item L<Net::IRC3>	824	=item L<Net::IRC3>
650		825
651	AnyEvent based IRC client module family.	826	AnyEvent based IRC client module family.
652		827
…		…
665		840
666	=item L<Coro>	841	=item L<Coro>
667		842
668	Has special support for AnyEvent via L<Coro::AnyEvent>.	843	Has special support for AnyEvent via L<Coro::AnyEvent>.
669		844
670	=item L<AnyEvent::AIO>, L<IO::AIO>
671
672	Truly asynchronous I/O, should be in the toolbox of every event
673	programmer. AnyEvent::AIO transparently fuses IO::AIO and AnyEvent
674	together.
675
676	=item L<AnyEvent::BDB>, L<BDB>
677
678	Truly asynchronous Berkeley DB access. AnyEvent::AIO transparently fuses
679	IO::AIO and AnyEvent together.
680
681	=item L<IO::Lambda>	845	=item L<IO::Lambda>
682		846
683	The lambda approach to I/O - don't ask, look there. Can use AnyEvent.	847	The lambda approach to I/O - don't ask, look there. Can use AnyEvent.
684		848
685	=back	849	=back
…		…
691	no warnings;	855	no warnings;
692	use strict;	856	use strict;
693		857
694	use Carp;	858	use Carp;
695		859
696	our $VERSION = '3.4';	860	our $VERSION = 4.22;
697	our $MODEL;	861	our $MODEL;
698		862
699	our $AUTOLOAD;	863	our $AUTOLOAD;
700	our @ISA;	864	our @ISA;
701		865
		866	our @REGISTRY;
		867
		868	our $WIN32;
		869
		870	BEGIN {
		871	my $win32 = ! ! ($^O =~ /mswin32/i);
		872	eval "sub WIN32(){ $win32 }";
		873	}
		874
702	our $verbose = $ENV{PERL_ANYEVENT_VERBOSE}*1;	875	our $verbose = $ENV{PERL_ANYEVENT_VERBOSE}*1;
703		876
704	our @REGISTRY;	877	our %PROTOCOL; # (ipv4\|ipv6) => (1\|2), higher numbers are preferred
		878
		879	{
		880	my $idx;
		881	$PROTOCOL{$_} = ++$idx
		882	for reverse split /\s,\s/,
		883	$ENV{PERL_ANYEVENT_PROTOCOLS} \|\| "ipv4,ipv6";
		884	}
705		885
706	my @models = (	886	my @models = (
707	[EV:: => AnyEvent::Impl::EV::],	887	[EV:: => AnyEvent::Impl::EV::],
708	[Event:: => AnyEvent::Impl::Event::],	888	[Event:: => AnyEvent::Impl::Event::],
709	[Tk:: => AnyEvent::Impl::Tk::],
710	[Wx:: => AnyEvent::Impl::POE::],
711	[Prima:: => AnyEvent::Impl::POE::],
712	[AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl::],	889	[AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl::],
713	# everything below here will not be autoprobed as the pureperl backend should work everywhere	890	# everything below here will not be autoprobed
714	[Glib:: => AnyEvent::Impl::Glib::],	891	# as the pureperl backend should work everywhere
		892	# and is usually faster
		893	[Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles
		894	[Glib:: => AnyEvent::Impl::Glib::], # becomes extremely slow with many watchers
715	[Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy	895	[Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy
716	[Qt:: => AnyEvent::Impl::Qt::], # requires special main program	896	[Qt:: => AnyEvent::Impl::Qt::], # requires special main program
717	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza	897	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza
		898	[Wx:: => AnyEvent::Impl::POE::],
		899	[Prima:: => AnyEvent::Impl::POE::],
718	);	900	);
719		901
720	our %method = map +($_ => 1), qw(io timer signal child condvar one_event DESTROY);	902	our %method = map +($_ => 1), qw(io timer time now signal child condvar one_event DESTROY);
721		903
722	our @post_detect;	904	our @post_detect;
723		905
724	sub post_detect(&) {	906	sub post_detect(&) {
725	my ($cb) = @_;	907	my ($cb) = @_;
…		…
730	1	912	1
731	} else {	913	} else {
732	push @post_detect, $cb;	914	push @post_detect, $cb;
733		915
734	defined wantarray	916	defined wantarray
735	? bless \$cb, "AnyEvent::Util::Guard"	917	? bless \$cb, "AnyEvent::Util::PostDetect"
736	: ()	918	: ()
737	}	919	}
738	}	920	}
739		921
740	sub AnyEvent::Util::Guard::DESTROY {	922	sub AnyEvent::Util::PostDetect::DESTROY {
741	@post_detect = grep $_ != ${$_[0]}, @post_detect;	923	@post_detect = grep $_ != ${$_[0]}, @post_detect;
742	}	924	}
743		925
744	sub detect() {	926	sub detect() {
745	unless ($MODEL) {	927	unless ($MODEL) {
746	no strict 'refs';	928	no strict 'refs';
		929	local $SIG{__DIE__};
747		930
748	if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) {	931	if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) {
749	my $model = "AnyEvent::Impl::$1";	932	my $model = "AnyEvent::Impl::$1";
750	if (eval "require $model") {	933	if (eval "require $model") {
751	$MODEL = $model;	934	$MODEL = $model;
…		…
785	$MODEL	968	$MODEL
786	or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV, Event or Glib.";	969	or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV, Event or Glib.";
787	}	970	}
788	}	971	}
789		972
		973	push @{"$MODEL\::ISA"}, "AnyEvent::Base";
		974
790	unshift @ISA, $MODEL;	975	unshift @ISA, $MODEL;
791	push @{"$MODEL\::ISA"}, "AnyEvent::Base";	976
		977	require AnyEvent::Strict if $ENV{PERL_ANYEVENT_STRICT};
792		978
793	(shift @post_detect)->() while @post_detect;	979	(shift @post_detect)->() while @post_detect;
794	}	980	}
795		981
796	$MODEL	982	$MODEL
…		…
806		992
807	my $class = shift;	993	my $class = shift;
808	$class->$func (@_);	994	$class->$func (@_);
809	}	995	}
810		996
		997	# utility function to dup a filehandle. this is used by many backends
		998	# to support binding more than one watcher per filehandle (they usually
		999	# allow only one watcher per fd, so we dup it to get a different one).
		1000	sub _dupfh($$$$) {
		1001	my ($poll, $fh, $r, $w) = @_;
		1002
		1003	require Fcntl;
		1004
		1005	# cygwin requires the fh mode to be matching, unix doesn't
		1006	my ($rw, $mode) = $poll eq "r" ? ($r, "<")
		1007	: $poll eq "w" ? ($w, ">")
		1008	: Carp::croak "AnyEvent->io requires poll set to either 'r' or 'w'";
		1009
		1010	open my $fh2, "$mode&" . fileno $fh
		1011	or die "cannot dup() filehandle: $!";
		1012
		1013	# we assume CLOEXEC is already set by perl in all important cases
		1014
		1015	($fh2, $rw)
		1016	}
		1017
811	package AnyEvent::Base;	1018	package AnyEvent::Base;
812		1019
		1020	# default implementation for now and time
		1021
		1022	use Time::HiRes ();
		1023
		1024	sub time { Time::HiRes::time }
		1025	sub now { Time::HiRes::time }
		1026
813	# default implementation for ->condvar, ->wait, ->broadcast	1027	# default implementation for ->condvar
814		1028
815	sub condvar {	1029	sub condvar {
816	bless \my $flag, "AnyEvent::Base::CondVar"	1030	bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, AnyEvent::CondVar::
817	}
818
819	sub AnyEvent::Base::CondVar::broadcast {
820	${$_[0]}++;
821	}
822
823	sub AnyEvent::Base::CondVar::wait {
824	AnyEvent->one_event while !${$_[0]};
825	}	1031	}
826		1032
827	# default implementation for ->signal	1033	# default implementation for ->signal
828		1034
829	our %SIG_CB;	1035	our %SIG_CB;
…		…
845	sub AnyEvent::Base::Signal::DESTROY {	1051	sub AnyEvent::Base::Signal::DESTROY {
846	my ($signal, $cb) = @{$_[0]};	1052	my ($signal, $cb) = @{$_[0]};
847		1053
848	delete $SIG_CB{$signal}{$cb};	1054	delete $SIG_CB{$signal}{$cb};
849		1055
850	$SIG{$signal} = 'DEFAULT' unless keys %{ $SIG_CB{$signal} };	1056	delete $SIG{$signal} unless keys %{ $SIG_CB{$signal} };
851	}	1057	}
852		1058
853	# default implementation for ->child	1059	# default implementation for ->child
854		1060
855	our %PID_CB;	1061	our %PID_CB;
…		…
882	or Carp::croak "required option 'pid' is missing";	1088	or Carp::croak "required option 'pid' is missing";
883		1089
884	$PID_CB{$pid}{$arg{cb}} = $arg{cb};	1090	$PID_CB{$pid}{$arg{cb}} = $arg{cb};
885		1091
886	unless ($WNOHANG) {	1092	unless ($WNOHANG) {
887	$WNOHANG = eval { require POSIX; &POSIX::WNOHANG } \|\| 1;	1093	$WNOHANG = eval { local $SIG{__DIE__}; require POSIX; &POSIX::WNOHANG } \|\| 1;
888	}	1094	}
889		1095
890	unless ($CHLD_W) {	1096	unless ($CHLD_W) {
891	$CHLD_W = AnyEvent->signal (signal => 'CHLD', cb => \&_sigchld);	1097	$CHLD_W = AnyEvent->signal (signal => 'CHLD', cb => \&_sigchld);
892	# child could be a zombie already, so make at least one round	1098	# child could be a zombie already, so make at least one round
…		…
902	delete $PID_CB{$pid}{$cb};	1108	delete $PID_CB{$pid}{$cb};
903	delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };	1109	delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };
904		1110
905	undef $CHLD_W unless keys %PID_CB;	1111	undef $CHLD_W unless keys %PID_CB;
906	}	1112	}
		1113
		1114	package AnyEvent::CondVar;
		1115
		1116	our @ISA = AnyEvent::CondVar::Base::;
		1117
		1118	package AnyEvent::CondVar::Base;
		1119
		1120	use overload
		1121	'&{}' => sub { my $self = shift; sub { $self->send (@_) } },
		1122	fallback => 1;
		1123
		1124	sub _send {
		1125	# nop
		1126	}
		1127
		1128	sub send {
		1129	my $cv = shift;
		1130	$cv->{_ae_sent} = [@_];
		1131	(delete $cv->{_ae_cb})->($cv) if $cv->{_ae_cb};
		1132	$cv->_send;
		1133	}
		1134
		1135	sub croak {
		1136	$_[0]{_ae_croak} = $_[1];
		1137	$_[0]->send;
		1138	}
		1139
		1140	sub ready {
		1141	$_[0]{_ae_sent}
		1142	}
		1143
		1144	sub _wait {
		1145	AnyEvent->one_event while !$_[0]{_ae_sent};
		1146	}
		1147
		1148	sub recv {
		1149	$_[0]->_wait;
		1150
		1151	Carp::croak $_[0]{_ae_croak} if $_[0]{_ae_croak};
		1152	wantarray ? @{ $_[0]{_ae_sent} } : $_[0]{_ae_sent}[0]
		1153	}
		1154
		1155	sub cb {
		1156	$_[0]{_ae_cb} = $_[1] if @_ > 1;
		1157	$_[0]{_ae_cb}
		1158	}
		1159
		1160	sub begin {
		1161	++$_[0]{_ae_counter};
		1162	$_[0]{_ae_end_cb} = $_[1] if @_ > 1;
		1163	}
		1164
		1165	sub end {
		1166	return if --$_[0]{_ae_counter};
		1167	&{ $_[0]{_ae_end_cb} \|\| sub { $_[0]->send } };
		1168	}
		1169
		1170	# undocumented/compatibility with pre-3.4
		1171	*broadcast = \&send;
		1172	*wait = \&_wait;
907		1173
908	=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE	1174	=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE
909		1175
910	This is an advanced topic that you do not normally need to use AnyEvent in	1176	This is an advanced topic that you do not normally need to use AnyEvent in
911	a module. This section is only of use to event loop authors who want to	1177	a module. This section is only of use to event loop authors who want to
…		…
965	C<PERL_ANYEVENT_MODEL>.	1231	C<PERL_ANYEVENT_MODEL>.
966		1232
967	When set to C<2> or higher, cause AnyEvent to report to STDERR which event	1233	When set to C<2> or higher, cause AnyEvent to report to STDERR which event
968	model it chooses.	1234	model it chooses.
969		1235
		1236	=item C<PERL_ANYEVENT_STRICT>
		1237
		1238	AnyEvent does not do much argument checking by default, as thorough
		1239	argument checking is very costly. Setting this variable to a true value
		1240	will cause AnyEvent to load C<AnyEvent::Strict> and then to thoroughly
		1241	check the arguments passed to most method calls. If it finds any problems
		1242	it will croak.
		1243
		1244	In other words, enables "strict" mode.
		1245
		1246	Unlike C<use strict> it is definitely recommended ot keep it off in
		1247	production.
		1248
970	=item C<PERL_ANYEVENT_MODEL>	1249	=item C<PERL_ANYEVENT_MODEL>
971		1250
972	This can be used to specify the event model to be used by AnyEvent, before	1251	This can be used to specify the event model to be used by AnyEvent, before
973	autodetection and -probing kicks in. It must be a string consisting	1252	auto detection and -probing kicks in. It must be a string consisting
974	entirely of ASCII letters. The string C<AnyEvent::Impl::> gets prepended	1253	entirely of ASCII letters. The string C<AnyEvent::Impl::> gets prepended
975	and the resulting module name is loaded and if the load was successful,	1254	and the resulting module name is loaded and if the load was successful,
976	used as event model. If it fails to load AnyEvent will proceed with	1255	used as event model. If it fails to load AnyEvent will proceed with
977	autodetection and -probing.	1256	auto detection and -probing.
978		1257
979	This functionality might change in future versions.	1258	This functionality might change in future versions.
980		1259
981	For example, to force the pure perl model (L<AnyEvent::Impl::Perl>) you	1260	For example, to force the pure perl model (L<AnyEvent::Impl::Perl>) you
982	could start your program like this:	1261	could start your program like this:
983		1262
984	PERL_ANYEVENT_MODEL=Perl perl ...	1263	PERL_ANYEVENT_MODEL=Perl perl ...
		1264
		1265	=item C<PERL_ANYEVENT_PROTOCOLS>
		1266
		1267	Used by both L<AnyEvent::DNS> and L<AnyEvent::Socket> to determine preferences
		1268	for IPv4 or IPv6. The default is unspecified (and might change, or be the result
		1269	of auto probing).
		1270
		1271	Must be set to a comma-separated list of protocols or address families,
		1272	current supported: C<ipv4> and C<ipv6>. Only protocols mentioned will be
		1273	used, and preference will be given to protocols mentioned earlier in the
		1274	list.
		1275
		1276	This variable can effectively be used for denial-of-service attacks
		1277	against local programs (e.g. when setuid), although the impact is likely
		1278	small, as the program has to handle connection errors already-
		1279
		1280	Examples: C<PERL_ANYEVENT_PROTOCOLS=ipv4,ipv6> - prefer IPv4 over IPv6,
		1281	but support both and try to use both. C<PERL_ANYEVENT_PROTOCOLS=ipv4>
		1282	- only support IPv4, never try to resolve or contact IPv6
		1283	addresses. C<PERL_ANYEVENT_PROTOCOLS=ipv6,ipv4> support either IPv4 or
		1284	IPv6, but prefer IPv6 over IPv4.
		1285
		1286	=item C<PERL_ANYEVENT_EDNS0>
		1287
		1288	Used by L<AnyEvent::DNS> to decide whether to use the EDNS0 extension
		1289	for DNS. This extension is generally useful to reduce DNS traffic, but
		1290	some (broken) firewalls drop such DNS packets, which is why it is off by
		1291	default.
		1292
		1293	Setting this variable to C<1> will cause L<AnyEvent::DNS> to announce
		1294	EDNS0 in its DNS requests.
		1295
		1296	=item C<PERL_ANYEVENT_MAX_FORKS>
		1297
		1298	The maximum number of child processes that C<AnyEvent::Util::fork_call>
		1299	will create in parallel.
985		1300
986	=back	1301	=back
987		1302
988	=head1 EXAMPLE PROGRAM	1303	=head1 EXAMPLE PROGRAM
989		1304
…		…
1000	poll => 'r',	1315	poll => 'r',
1001	cb => sub {	1316	cb => sub {
1002	warn "io event <$_[0]>\n"; # will always output <r>	1317	warn "io event <$_[0]>\n"; # will always output <r>
1003	chomp (my $input = <STDIN>); # read a line	1318	chomp (my $input = <STDIN>); # read a line
1004	warn "read: $input\n"; # output what has been read	1319	warn "read: $input\n"; # output what has been read
1005	$cv->broadcast if $input =~ /^q/i; # quit program if /^q/i	1320	$cv->send if $input =~ /^q/i; # quit program if /^q/i
1006	},	1321	},
1007	);	1322	);
1008		1323
1009	my $time_watcher; # can only be used once	1324	my $time_watcher; # can only be used once
1010		1325
…		…
1015	});	1330	});
1016	}	1331	}
1017		1332
1018	new_timer; # create first timer	1333	new_timer; # create first timer
1019		1334
1020	$cv->wait; # wait until user enters /^q/i	1335	$cv->recv; # wait until user enters /^q/i
1021		1336
1022	=head1 REAL-WORLD EXAMPLE	1337	=head1 REAL-WORLD EXAMPLE
1023		1338
1024	Consider the L<Net::FCP> module. It features (among others) the following	1339	Consider the L<Net::FCP> module. It features (among others) the following
1025	API calls, which are to freenet what HTTP GET requests are to http:	1340	API calls, which are to freenet what HTTP GET requests are to http:
…		…
1075	syswrite $txn->{fh}, $txn->{request}	1390	syswrite $txn->{fh}, $txn->{request}
1076	or die "connection or write error";	1391	or die "connection or write error";
1077	$txn->{w} = AnyEvent->io (fh => $txn->{fh}, poll => 'r', cb => sub { $txn->fh_ready_r });	1392	$txn->{w} = AnyEvent->io (fh => $txn->{fh}, poll => 'r', cb => sub { $txn->fh_ready_r });
1078		1393
1079	Again, C<fh_ready_r> waits till all data has arrived, and then stores the	1394	Again, C<fh_ready_r> waits till all data has arrived, and then stores the
1080	result and signals any possible waiters that the request ahs finished:	1395	result and signals any possible waiters that the request has finished:
1081		1396
1082	sysread $txn->{fh}, $txn->{buf}, length $txn->{$buf};	1397	sysread $txn->{fh}, $txn->{buf}, length $txn->{$buf};
1083		1398
1084	if (end-of-file or data complete) {	1399	if (end-of-file or data complete) {
1085	$txn->{result} = $txn->{buf};	1400	$txn->{result} = $txn->{buf};
1086	$txn->{finished}->broadcast;	1401	$txn->{finished}->send;
1087	$txb->{cb}->($txn) of $txn->{cb}; # also call callback	1402	$txb->{cb}->($txn) of $txn->{cb}; # also call callback
1088	}	1403	}
1089		1404
1090	The C<result> method, finally, just waits for the finished signal (if the	1405	The C<result> method, finally, just waits for the finished signal (if the
1091	request was already finished, it doesn't wait, of course, and returns the	1406	request was already finished, it doesn't wait, of course, and returns the
1092	data:	1407	data:
1093		1408
1094	$txn->{finished}->wait;	1409	$txn->{finished}->recv;
1095	return $txn->{result};	1410	return $txn->{result};
1096		1411
1097	The actual code goes further and collects all errors (C<die>s, exceptions)	1412	The actual code goes further and collects all errors (C<die>s, exceptions)
1098	that occured during request processing. The C<result> method detects	1413	that occurred during request processing. The C<result> method detects
1099	whether an exception as thrown (it is stored inside the $txn object)	1414	whether an exception as thrown (it is stored inside the $txn object)
1100	and just throws the exception, which means connection errors and other	1415	and just throws the exception, which means connection errors and other
1101	problems get reported tot he code that tries to use the result, not in a	1416	problems get reported tot he code that tries to use the result, not in a
1102	random callback.	1417	random callback.
1103		1418
…		…
1134		1449
1135	my $quit = AnyEvent->condvar;	1450	my $quit = AnyEvent->condvar;
1136		1451
1137	$fcp->txn_client_get ($url)->cb (sub {	1452	$fcp->txn_client_get ($url)->cb (sub {
1138	...	1453	...
1139	$quit->broadcast;	1454	$quit->send;
1140	});	1455	});
1141		1456
1142	$quit->wait;	1457	$quit->recv;
1143		1458
1144		1459
1145	=head1 BENCHMARKS	1460	=head1 BENCHMARKS
1146		1461
1147	To give you an idea of the performance and overheads that AnyEvent adds	1462	To give you an idea of the performance and overheads that AnyEvent adds
…		…
1149	of various event loops I prepared some benchmarks.	1464	of various event loops I prepared some benchmarks.
1150		1465
1151	=head2 BENCHMARKING ANYEVENT OVERHEAD	1466	=head2 BENCHMARKING ANYEVENT OVERHEAD
1152		1467
1153	Here is a benchmark of various supported event models used natively and	1468	Here is a benchmark of various supported event models used natively and
1154	through anyevent. The benchmark creates a lot of timers (with a zero	1469	through AnyEvent. The benchmark creates a lot of timers (with a zero
1155	timeout) and I/O watchers (watching STDOUT, a pty, to become writable,	1470	timeout) and I/O watchers (watching STDOUT, a pty, to become writable,
1156	which it is), lets them fire exactly once and destroys them again.	1471	which it is), lets them fire exactly once and destroys them again.
1157		1472
1158	Source code for this benchmark is found as F<eg/bench> in the AnyEvent	1473	Source code for this benchmark is found as F<eg/bench> in the AnyEvent
1159	distribution.	1474	distribution.
…		…
1176	all watchers, to avoid adding memory overhead. That means closure creation	1491	all watchers, to avoid adding memory overhead. That means closure creation
1177	and memory usage is not included in the figures.	1492	and memory usage is not included in the figures.
1178		1493
1179	I<invoke> is the time, in microseconds, used to invoke a simple	1494	I<invoke> is the time, in microseconds, used to invoke a simple
1180	callback. The callback simply counts down a Perl variable and after it was	1495	callback. The callback simply counts down a Perl variable and after it was
1181	invoked "watcher" times, it would C<< ->broadcast >> a condvar once to	1496	invoked "watcher" times, it would C<< ->send >> a condvar once to
1182	signal the end of this phase.	1497	signal the end of this phase.
1183		1498
1184	I<destroy> is the time, in microseconds, that it takes to destroy a single	1499	I<destroy> is the time, in microseconds, that it takes to destroy a single
1185	watcher.	1500	watcher.
1186		1501
…		…
1282		1597
1283	=back	1598	=back
1284		1599
1285	=head2 BENCHMARKING THE LARGE SERVER CASE	1600	=head2 BENCHMARKING THE LARGE SERVER CASE
1286		1601
1287	This benchmark atcually benchmarks the event loop itself. It works by	1602	This benchmark actually benchmarks the event loop itself. It works by
1288	creating a number of "servers": each server consists of a socketpair, a	1603	creating a number of "servers": each server consists of a socket pair, a
1289	timeout watcher that gets reset on activity (but never fires), and an I/O	1604	timeout watcher that gets reset on activity (but never fires), and an I/O
1290	watcher waiting for input on one side of the socket. Each time the socket	1605	watcher waiting for input on one side of the socket. Each time the socket
1291	watcher reads a byte it will write that byte to a random other "server".	1606	watcher reads a byte it will write that byte to a random other "server".
1292		1607
1293	The effect is that there will be a lot of I/O watchers, only part of which	1608	The effect is that there will be a lot of I/O watchers, only part of which
1294	are active at any one point (so there is a constant number of active	1609	are active at any one point (so there is a constant number of active
1295	fds for each loop iterstaion, but which fds these are is random). The	1610	fds for each loop iteration, but which fds these are is random). The
1296	timeout is reset each time something is read because that reflects how	1611	timeout is reset each time something is read because that reflects how
1297	most timeouts work (and puts extra pressure on the event loops).	1612	most timeouts work (and puts extra pressure on the event loops).
1298		1613
1299	In this benchmark, we use 10000 socketpairs (20000 sockets), of which 100	1614	In this benchmark, we use 10000 socket pairs (20000 sockets), of which 100
1300	(1%) are active. This mirrors the activity of large servers with many	1615	(1%) are active. This mirrors the activity of large servers with many
1301	connections, most of which are idle at any one point in time.	1616	connections, most of which are idle at any one point in time.
1302		1617
1303	Source code for this benchmark is found as F<eg/bench2> in the AnyEvent	1618	Source code for this benchmark is found as F<eg/bench2> in the AnyEvent
1304	distribution.	1619	distribution.
…		…
1306	=head3 Explanation of the columns	1621	=head3 Explanation of the columns
1307		1622
1308	I<sockets> is the number of sockets, and twice the number of "servers" (as	1623	I<sockets> is the number of sockets, and twice the number of "servers" (as
1309	each server has a read and write socket end).	1624	each server has a read and write socket end).
1310		1625
1311	I<create> is the time it takes to create a socketpair (which is	1626	I<create> is the time it takes to create a socket pair (which is
1312	nontrivial) and two watchers: an I/O watcher and a timeout watcher.	1627	nontrivial) and two watchers: an I/O watcher and a timeout watcher.
1313		1628
1314	I<request>, the most important value, is the time it takes to handle a	1629	I<request>, the most important value, is the time it takes to handle a
1315	single "request", that is, reading the token from the pipe and forwarding	1630	single "request", that is, reading the token from the pipe and forwarding
1316	it to another server. This includes deleting the old timeout and creating	1631	it to another server. This includes deleting the old timeout and creating
…		…
1389	speed most when you have lots of watchers, not when you only have a few of	1704	speed most when you have lots of watchers, not when you only have a few of
1390	them).	1705	them).
1391		1706
1392	EV is again fastest.	1707	EV is again fastest.
1393		1708
1394	Perl again comes second. It is noticably faster than the C-based event	1709	Perl again comes second. It is noticeably faster than the C-based event
1395	loops Event and Glib, although the difference is too small to really	1710	loops Event and Glib, although the difference is too small to really
1396	matter.	1711	matter.
1397		1712
1398	POE also performs much better in this case, but is is still far behind the	1713	POE also performs much better in this case, but is is still far behind the
1399	others.	1714	others.
…		…
1428	specified in the variable.	1743	specified in the variable.
1429		1744
1430	You can make AnyEvent completely ignore this variable by deleting it	1745	You can make AnyEvent completely ignore this variable by deleting it
1431	before the first watcher gets created, e.g. with a C<BEGIN> block:	1746	before the first watcher gets created, e.g. with a C<BEGIN> block:
1432		1747
1433	BEGIN { delete $ENV{PERL_ANYEVENT_MODEL} }	1748	BEGIN { delete $ENV{PERL_ANYEVENT_MODEL} }
1434		1749
1435	use AnyEvent;	1750	use AnyEvent;
1436		1751
1437	Similar considerations apply to $ENV{PERL_ANYEVENT_VERBOSE}, as that can	1752	Similar considerations apply to $ENV{PERL_ANYEVENT_VERBOSE}, as that can
1438	be used to probe what backend is used and gain other information (which is	1753	be used to probe what backend is used and gain other information (which is
1439	probably even less useful to an attacker than PERL_ANYEVENT_MODEL).	1754	probably even less useful to an attacker than PERL_ANYEVENT_MODEL), and
		1755	$ENV{PERL_ANYEGENT_STRICT}.
		1756
		1757
		1758	=head1 BUGS
		1759
		1760	Perl 5.8 has numerous memleaks that sometimes hit this module and are hard
		1761	to work around. If you suffer from memleaks, first upgrade to Perl 5.10
		1762	and check wether the leaks still show up. (Perl 5.10.0 has other annoying
		1763	mamleaks, such as leaking on C<map> and C<grep> but it is usually not as
		1764	pronounced).
1440		1765
1441		1766
1442	=head1 SEE ALSO	1767	=head1 SEE ALSO
		1768
		1769	Utility functions: L<AnyEvent::Util>.
1443		1770
1444	Event modules: L<EV>, L<EV::Glib>, L<Glib::EV>, L<Event>, L<Glib::Event>,	1771	Event modules: L<EV>, L<EV::Glib>, L<Glib::EV>, L<Event>, L<Glib::Event>,
1445	L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>.	1772	L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>.
1446		1773
1447	Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>,	1774	Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>,
1448	L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>,	1775	L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>,
1449	L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>,	1776	L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>,
1450	L<AnyEvent::Impl::POE>.	1777	L<AnyEvent::Impl::POE>.
1451		1778
		1779	Non-blocking file handles, sockets, TCP clients and
		1780	servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>.
		1781
		1782	Asynchronous DNS: L<AnyEvent::DNS>.
		1783
1452	Coroutine support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>, L<Coro::Event>,	1784	Coroutine support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>, L<Coro::Event>,
1453		1785
1454	Nontrivial usage examples: L<Net::FCP>, L<Net::XMPP2>.	1786	Nontrivial usage examples: L<Net::FCP>, L<Net::XMPP2>, L<AnyEvent::DNS>.
1455		1787
1456		1788
1457	=head1 AUTHOR	1789	=head1 AUTHOR
1458		1790
1459	Marc Lehmann <schmorp@schmorp.de>	1791	Marc Lehmann <schmorp@schmorp.de>
1460	http://home.schmorp.de/	1792	http://home.schmorp.de/
1461		1793
1462	=cut	1794	=cut
1463		1795
1464	1	1796	1
1465		1797

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Comparing AnyEvent/lib/AnyEvent.pm (file contents): Revision 1.113 by root, Sat May 10 20:30:35 2008 UTC vs. Revision 1.173 by root, Mon Jul 21 03:47:22 2008 UTC

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Comparing AnyEvent/lib/AnyEvent.pm (file contents):
Revision 1.113 by root, Sat May 10 20:30:35 2008 UTC vs.
Revision 1.173 by root, Mon Jul 21 03:47:22 2008 UTC