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

Comparing AnyEvent/lib/AnyEvent.pm (file contents):
Revision 1.112 by root, Sat May 10 01:04:42 2008 UTC vs.
Revision 1.175 by root, Sun Jul 27 08:43:32 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
…		…
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
313	>> method, usually without arguments. The only argument pair allowed is	394	>> method, usually without arguments. The only argument pair allowed is
		395
314	C<cb>, which specifies a callback to be called when the condition variable	396	C<cb>, which specifies a callback to be called when the condition variable
315	becomes true.	397	becomes true, with the condition variable as the first argument (but not
		398	the results).
316		399
317	After creation, the conditon variable is "false" until it becomes "true"	400	After creation, the condition variable is "false" until it becomes "true"
318	by calling the C<send> method.	401	by calling the C<send> method (or calling the condition variable as if it
		402	were a callback, read about the caveats in the description for the C<<
		403	->send >> method).
319		404
320	Condition variables are similar to callbacks, except that you can	405	Condition variables are similar to callbacks, except that you can
321	optionally wait for them. They can also be called merge points - points	406	optionally wait for them. They can also be called merge points - points
322	in time where multiple outstandign events have been processed. And yet	407	in time where multiple outstanding events have been processed. And yet
323	another way to call them is transations - each condition variable can be	408	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	409	used to represent a transaction, which finishes at some point and delivers
325	a result.	410	a result.
326		411
327	Condition variables are very useful to signal that something has finished,	412	Condition variables are very useful to signal that something has finished,
328	for example, if you write a module that does asynchronous http requests,	413	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	414	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	415	availability of results. The user can either act when the callback is
331	called or can synchronously C<< ->wait >> for the results.	416	called or can synchronously C<< ->recv >> for the results.
332		417
333	You can also use them to simulate traditional event loops - for example,	418	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	419	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	420	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.	421	button of your app, which would C<< ->send >> the "quit" event.
337		422
338	Note that condition variables recurse into the event loop - if you have	423	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	424	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	425	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,	426	you should avoid making a blocking wait yourself, at least in callbacks,
342	as this asks for trouble.	427	as this asks for trouble.
343		428
344	Condition variables are represented by hash refs in perl, and the keys	429	Condition variables are represented by hash refs in perl, and the keys
…		…
349		434
350	There are two "sides" to a condition variable - the "producer side" which	435	There are two "sides" to a condition variable - the "producer side" which
351	eventually calls C<< -> send >>, and the "consumer side", which waits	436	eventually calls C<< -> send >>, and the "consumer side", which waits
352	for the send to occur.	437	for the send to occur.
353		438
354	Example:	439	Example: wait for a timer.
355		440
356	# wait till the result is ready	441	# wait till the result is ready
357	my $result_ready = AnyEvent->condvar;	442	my $result_ready = AnyEvent->condvar;
358		443
359	# do something such as adding a timer	444	# do something such as adding a timer
…		…
365	cb => sub { $result_ready->send },	450	cb => sub { $result_ready->send },
366	);	451	);
367		452
368	# this "blocks" (while handling events) till the callback	453	# this "blocks" (while handling events) till the callback
369	# calls send	454	# calls send
370	$result_ready->wait;	455	$result_ready->recv;
		456
		457	Example: wait for a timer, but take advantage of the fact that
		458	condition variables are also code references.
		459
		460	my $done = AnyEvent->condvar;
		461	my $delay = AnyEvent->timer (after => 5, cb => $done);
		462	$done->recv;
		463
		464	Example: Imagine an API that returns a condvar and doesn't support
		465	callbacks. This is how you make a synchronous call, for example from
		466	the main program:
		467
		468	use AnyEvent::CouchDB;
		469
		470	...
		471
		472	my @info = $couchdb->info->recv;
		473
		474	And this is how you would just ste a callback to be called whenever the
		475	results are available:
		476
		477	$couchdb->info->cb (sub {
		478	my @info = $_[0]->recv;
		479	});
371		480
372	=head3 METHODS FOR PRODUCERS	481	=head3 METHODS FOR PRODUCERS
373		482
374	These methods should only be used by the producing side, i.e. the	483	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	484	code/module that eventually sends the signal. Note that it is also
…		…
378		487
379	=over 4	488	=over 4
380		489
381	=item $cv->send (...)	490	=item $cv->send (...)
382		491
383	Flag the condition as ready - a running C<< ->wait >> and all further	492	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	493	calls to C<recv> will (eventually) return after this method has been
385	called. If nobody is waiting the send will be remembered.	494	called. If nobody is waiting the send will be remembered.
386		495
387	If a callback has been set on the condition variable, it is called	496	If a callback has been set on the condition variable, it is called
388	immediately from within send.	497	immediately from within send.
389		498
390	Any arguments passed to the C<send> call will be returned by all	499	Any arguments passed to the C<send> call will be returned by all
391	future C<< ->wait >> calls.	500	future C<< ->recv >> calls.
		501
		502	Condition variables are overloaded so one can call them directly
		503	(as a code reference). Calling them directly is the same as calling
		504	C<send>. Note, however, that many C-based event loops do not handle
		505	overloading, so as tempting as it may be, passing a condition variable
		506	instead of a callback does not work. Both the pure perl and EV loops
		507	support overloading, however, as well as all functions that use perl to
		508	invoke a callback (as in L<AnyEvent::Socket> and L<AnyEvent::DNS> for
		509	example).
392		510
393	=item $cv->croak ($error)	511	=item $cv->croak ($error)
394		512
395	Similar to send, but causes all call's wait C<< ->wait >> to invoke	513	Similar to send, but causes all call's to C<< ->recv >> to invoke
396	C<Carp::croak> with the given error message/object/scalar.	514	C<Carp::croak> with the given error message/object/scalar.
397		515
398	This can be used to signal any errors to the condition variable	516	This can be used to signal any errors to the condition variable
399	user/consumer.	517	user/consumer.
400		518
401	=item $cv->begin ([group callback])	519	=item $cv->begin ([group callback])
402		520
403	=item $cv->end	521	=item $cv->end
		522
		523	These two methods are EXPERIMENTAL and MIGHT CHANGE.
404		524
405	These two methods can be used to combine many transactions/events into	525	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	526	one. For example, a function that pings many hosts in parallel might want
407	to use a condition variable for the whole process.	527	to use a condition variable for the whole process.
408		528
…		…
443	doesn't execute once).	563	doesn't execute once).
444		564
445	This is the general pattern when you "fan out" into multiple subrequests:	565	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>	566	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	567	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>.	568	C<begin> and for each subrequest you finish, call C<end>.
449		569
450	=back	570	=back
451		571
452	=head3 METHODS FOR CONSUMERS	572	=head3 METHODS FOR CONSUMERS
453		573
454	These methods should only be used by the consuming side, i.e. the	574	These methods should only be used by the consuming side, i.e. the
455	code awaits the condition.	575	code awaits the condition.
456		576
457	=over 4	577	=over 4
458		578
459	=item $cv->wait	579	=item $cv->recv
460		580
461	Wait (blocking if necessary) until the C<< ->send >> or C<< ->croak	581	Wait (blocking if necessary) until the C<< ->send >> or C<< ->croak
462	>> methods have been called on c<$cv>, while servicing other watchers	582	>> methods have been called on c<$cv>, while servicing other watchers
463	normally.	583	normally.
464		584
…		…
475	(programs might want to do that to stay interactive), so I<if you are	595	(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	596	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	597	caller decide whether the call will block or not (for example, by coupling
478	condition variables with some kind of request results and supporting	598	condition variables with some kind of request results and supporting
479	callbacks so the caller knows that getting the result will not block,	599	callbacks so the caller knows that getting the result will not block,
480	while still suppporting blocking waits if the caller so desires).	600	while still supporting blocking waits if the caller so desires).
481		601
482	Another reason I<never> to C<< ->wait >> in a module is that you cannot	602	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	603	sensibly have two C<< ->recv >>'s in parallel, as that would require
484	multiple interpreters or coroutines/threads, none of which C<AnyEvent>	604	multiple interpreters or coroutines/threads, none of which C<AnyEvent>
485	can supply.	605	can supply.
486		606
487	The L<Coro> module, however, I<can> and I<does> supply coroutines and, in	607	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	608	fact, L<Coro::AnyEvent> replaces AnyEvent's condvars by coroutine-safe
489	versions and also integrates coroutines into AnyEvent, making blocking	609	versions and also integrates coroutines into AnyEvent, making blocking
490	C<< ->wait >> calls perfectly safe as long as they are done from another	610	C<< ->recv >> calls perfectly safe as long as they are done from another
491	coroutine (one that doesn't run the event loop).	611	coroutine (one that doesn't run the event loop).
492		612
493	You can ensure that C<< -wait >> never blocks by setting a callback and	613	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	614	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	615	time). This will work even when the event loop does not support blocking
496	waits otherwise.	616	waits otherwise.
497		617
498	=item $bool = $cv->ready	618	=item $bool = $cv->ready
499		619
500	Returns true when the condition is "true", i.e. whether C<send> or	620	Returns true when the condition is "true", i.e. whether C<send> or
501	C<croak> have been called.	621	C<croak> have been called.
502		622
503	=item $cb = $cv->cb ([new callback])	623	=item $cb = $cv->cb ($cb->($cv))
504		624
505	This is a mutator function that returns the callback set and optionally	625	This is a mutator function that returns the callback set and optionally
506	replaces it before doing so.	626	replaces it before doing so.
507		627
508	The callback will be called when the condition becomes "true", i.e. when	628	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	629	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.	630	variable itself. Calling C<recv> inside the callback or at any later time
		631	is guaranteed not to block.
511		632
512	=back	633	=back
513		634
514	=head1 GLOBAL VARIABLES AND FUNCTIONS	635	=head1 GLOBAL VARIABLES AND FUNCTIONS
515		636
…		…
582	Be careful when you create watchers in the module body - AnyEvent will	703	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	704	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	705	by calling AnyEvent in your module body you force the user of your module
585	to load the event module first.	706	to load the event module first.
586		707
587	Never call C<< ->wait >> on a condition variable unless you I<know> that	708	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	709	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	710	because it will stall the whole program, and the whole point of using
590	events is to stay interactive.	711	events is to stay interactive.
591		712
592	It is fine, however, to call C<< ->wait >> when the user of your module	713	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	714	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 >>	715	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).	716	freely, as the user of your module knows what she is doing. always).
596		717
597	=head1 WHAT TO DO IN THE MAIN PROGRAM	718	=head1 WHAT TO DO IN THE MAIN PROGRAM
598		719
599	There will always be a single main program - the only place that should	720	There will always be a single main program - the only place that should
…		…
601		722
602	If it doesn't care, it can just "use AnyEvent" and use it itself, or not	723	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	724	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.	725	decide which implementation to chose if some module relies on it.
605		726
606	If the main program relies on a specific event model. For example, in	727	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	728	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	729	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	730	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	731	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	732	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.	733	might chose the wrong one unless you load the correct one yourself.
613		734
614	You can chose to use a rather inefficient pure-perl implementation by	735	You can chose to use a pure-perl implementation by loading the
615	loading the C<AnyEvent::Impl::Perl> module, which gives you similar	736	C<AnyEvent::Impl::Perl> module, which gives you similar behaviour
616	behaviour everywhere, but letting AnyEvent chose is generally better.	737	everywhere, but letting AnyEvent chose the model is generally better.
		738
		739	=head2 MAINLOOP EMULATION
		740
		741	Sometimes (often for short test scripts, or even standalone programs who
		742	only want to use AnyEvent), you do not want to run a specific event loop.
		743
		744	In that case, you can use a condition variable like this:
		745
		746	AnyEvent->condvar->recv;
		747
		748	This has the effect of entering the event loop and looping forever.
		749
		750	Note that usually your program has some exit condition, in which case
		751	it is better to use the "traditional" approach of storing a condition
		752	variable somewhere, waiting for it, and sending it when the program should
		753	exit cleanly.
		754
617		755
618	=head1 OTHER MODULES	756	=head1 OTHER MODULES
619		757
620	The following is a non-exhaustive list of additional modules that use	758	The following is a non-exhaustive list of additional modules that use
621	AnyEvent and can therefore be mixed easily with other AnyEvent modules	759	AnyEvent and can therefore be mixed easily with other AnyEvent modules
…		…
627	=item L<AnyEvent::Util>	765	=item L<AnyEvent::Util>
628		766
629	Contains various utility functions that replace often-used but blocking	767	Contains various utility functions that replace often-used but blocking
630	functions such as C<inet_aton> by event-/callback-based versions.	768	functions such as C<inet_aton> by event-/callback-based versions.
631		769
		770	=item L<AnyEvent::Socket>
		771
		772	Provides various utility functions for (internet protocol) sockets,
		773	addresses and name resolution. Also functions to create non-blocking tcp
		774	connections or tcp servers, with IPv6 and SRV record support and more.
		775
632	=item L<AnyEvent::Handle>	776	=item L<AnyEvent::Handle>
633		777
634	Provide read and write buffers and manages watchers for reads and writes.	778	Provide read and write buffers, manages watchers for reads and writes,
		779	supports raw and formatted I/O, I/O queued and fully transparent and
		780	non-blocking SSL/TLS.
635		781
636	=item L<AnyEvent::Socket>	782	=item L<AnyEvent::DNS>
637		783
638	Provides a means to do non-blocking connects, accepts etc.	784	Provides rich asynchronous DNS resolver capabilities.
		785
		786	=item L<AnyEvent::HTTP>
		787
		788	A simple-to-use HTTP library that is capable of making a lot of concurrent
		789	HTTP requests.
639		790
640	=item L<AnyEvent::HTTPD>	791	=item L<AnyEvent::HTTPD>
641		792
642	Provides a simple web application server framework.	793	Provides a simple web application server framework.
643		794
644	=item L<AnyEvent::DNS>
645
646	Provides asynchronous DNS resolver capabilities, beyond what
647	L<AnyEvent::Util> offers.
648
649	=item L<AnyEvent::FastPing>	795	=item L<AnyEvent::FastPing>
650		796
651	The fastest ping in the west.	797	The fastest ping in the west.
		798
		799	=item L<AnyEvent::DBI>
		800
		801	Executes L<DBI> requests asynchronously in a proxy process.
		802
		803	=item L<AnyEvent::AIO>
		804
		805	Truly asynchronous I/O, should be in the toolbox of every event
		806	programmer. AnyEvent::AIO transparently fuses L<IO::AIO> and AnyEvent
		807	together.
		808
		809	=item L<AnyEvent::BDB>
		810
		811	Truly asynchronous Berkeley DB access. AnyEvent::BDB transparently fuses
		812	L<BDB> and AnyEvent together.
		813
		814	=item L<AnyEvent::GPSD>
		815
		816	A non-blocking interface to gpsd, a daemon delivering GPS information.
		817
		818	=item L<AnyEvent::IGS>
		819
		820	A non-blocking interface to the Internet Go Server protocol (used by
		821	L<App::IGS>).
652		822
653	=item L<Net::IRC3>	823	=item L<Net::IRC3>
654		824
655	AnyEvent based IRC client module family.	825	AnyEvent based IRC client module family.
656		826
…		…
673		843
674	=item L<IO::Lambda>	844	=item L<IO::Lambda>
675		845
676	The lambda approach to I/O - don't ask, look there. Can use AnyEvent.	846	The lambda approach to I/O - don't ask, look there. Can use AnyEvent.
677		847
678	=item L<IO::AIO>
679
680	Truly asynchronous I/O, should be in the toolbox of every event
681	programmer. Can be trivially made to use AnyEvent.
682
683	=item L<BDB>
684
685	Truly asynchronous Berkeley DB access. Can be trivially made to use
686	AnyEvent.
687
688	=back	848	=back
689		849
690	=cut	850	=cut
691		851
692	package AnyEvent;	852	package AnyEvent;
…		…
694	no warnings;	854	no warnings;
695	use strict;	855	use strict;
696		856
697	use Carp;	857	use Carp;
698		858
699	our $VERSION = '3.4';	859	our $VERSION = 4.23;
700	our $MODEL;	860	our $MODEL;
701		861
702	our $AUTOLOAD;	862	our $AUTOLOAD;
703	our @ISA;	863	our @ISA;
704		864
		865	our @REGISTRY;
		866
		867	our $WIN32;
		868
		869	BEGIN {
		870	my $win32 = ! ! ($^O =~ /mswin32/i);
		871	eval "sub WIN32(){ $win32 }";
		872	}
		873
705	our $verbose = $ENV{PERL_ANYEVENT_VERBOSE}*1;	874	our $verbose = $ENV{PERL_ANYEVENT_VERBOSE}*1;
706		875
707	our @REGISTRY;	876	our %PROTOCOL; # (ipv4\|ipv6) => (1\|2), higher numbers are preferred
		877
		878	{
		879	my $idx;
		880	$PROTOCOL{$_} = ++$idx
		881	for reverse split /\s,\s/,
		882	$ENV{PERL_ANYEVENT_PROTOCOLS} \|\| "ipv4,ipv6";
		883	}
708		884
709	my @models = (	885	my @models = (
710	[EV:: => AnyEvent::Impl::EV::],	886	[EV:: => AnyEvent::Impl::EV::],
711	[Event:: => AnyEvent::Impl::Event::],	887	[Event:: => AnyEvent::Impl::Event::],
712	[Tk:: => AnyEvent::Impl::Tk::],
713	[Wx:: => AnyEvent::Impl::POE::],
714	[Prima:: => AnyEvent::Impl::POE::],
715	[AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl::],	888	[AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl::],
716	# everything below here will not be autoprobed as the pureperl backend should work everywhere	889	# everything below here will not be autoprobed
717	[Glib:: => AnyEvent::Impl::Glib::],	890	# as the pureperl backend should work everywhere
		891	# and is usually faster
		892	[Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles
		893	[Glib:: => AnyEvent::Impl::Glib::], # becomes extremely slow with many watchers
718	[Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy	894	[Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy
719	[Qt:: => AnyEvent::Impl::Qt::], # requires special main program	895	[Qt:: => AnyEvent::Impl::Qt::], # requires special main program
720	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza	896	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza
		897	[Wx:: => AnyEvent::Impl::POE::],
		898	[Prima:: => AnyEvent::Impl::POE::],
721	);	899	);
722		900
723	our %method = map +($_ => 1), qw(io timer signal child condvar one_event DESTROY);	901	our %method = map +($_ => 1), qw(io timer time now signal child condvar one_event DESTROY);
724		902
725	our @post_detect;	903	our @post_detect;
726		904
727	sub post_detect(&) {	905	sub post_detect(&) {
728	my ($cb) = @_;	906	my ($cb) = @_;
…		…
733	1	911	1
734	} else {	912	} else {
735	push @post_detect, $cb;	913	push @post_detect, $cb;
736		914
737	defined wantarray	915	defined wantarray
738	? bless \$cb, "AnyEvent::Util::Guard"	916	? bless \$cb, "AnyEvent::Util::PostDetect"
739	: ()	917	: ()
740	}	918	}
741	}	919	}
742		920
743	sub AnyEvent::Util::Guard::DESTROY {	921	sub AnyEvent::Util::PostDetect::DESTROY {
744	@post_detect = grep $_ != ${$_[0]}, @post_detect;	922	@post_detect = grep $_ != ${$_[0]}, @post_detect;
745	}	923	}
746		924
747	sub detect() {	925	sub detect() {
748	unless ($MODEL) {	926	unless ($MODEL) {
749	no strict 'refs';	927	no strict 'refs';
		928	local $SIG{__DIE__};
750		929
751	if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) {	930	if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) {
752	my $model = "AnyEvent::Impl::$1";	931	my $model = "AnyEvent::Impl::$1";
753	if (eval "require $model") {	932	if (eval "require $model") {
754	$MODEL = $model;	933	$MODEL = $model;
…		…
788	$MODEL	967	$MODEL
789	or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV, Event or Glib.";	968	or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV, Event or Glib.";
790	}	969	}
791	}	970	}
792		971
		972	push @{"$MODEL\::ISA"}, "AnyEvent::Base";
		973
793	unshift @ISA, $MODEL;	974	unshift @ISA, $MODEL;
794	push @{"$MODEL\::ISA"}, "AnyEvent::Base";	975
		976	require AnyEvent::Strict if $ENV{PERL_ANYEVENT_STRICT};
795		977
796	(shift @post_detect)->() while @post_detect;	978	(shift @post_detect)->() while @post_detect;
797	}	979	}
798		980
799	$MODEL	981	$MODEL
…		…
809		991
810	my $class = shift;	992	my $class = shift;
811	$class->$func (@_);	993	$class->$func (@_);
812	}	994	}
813		995
		996	# utility function to dup a filehandle. this is used by many backends
		997	# to support binding more than one watcher per filehandle (they usually
		998	# allow only one watcher per fd, so we dup it to get a different one).
		999	sub _dupfh($$$$) {
		1000	my ($poll, $fh, $r, $w) = @_;
		1001
		1002	require Fcntl;
		1003
		1004	# cygwin requires the fh mode to be matching, unix doesn't
		1005	my ($rw, $mode) = $poll eq "r" ? ($r, "<")
		1006	: $poll eq "w" ? ($w, ">")
		1007	: Carp::croak "AnyEvent->io requires poll set to either 'r' or 'w'";
		1008
		1009	open my $fh2, "$mode&" . fileno $fh
		1010	or die "cannot dup() filehandle: $!";
		1011
		1012	# we assume CLOEXEC is already set by perl in all important cases
		1013
		1014	($fh2, $rw)
		1015	}
		1016
814	package AnyEvent::Base;	1017	package AnyEvent::Base;
815		1018
		1019	# default implementation for now and time
		1020
		1021	use Time::HiRes ();
		1022
		1023	sub time { Time::HiRes::time }
		1024	sub now { Time::HiRes::time }
		1025
816	# default implementation for ->condvar, ->wait, ->broadcast	1026	# default implementation for ->condvar
817		1027
818	sub condvar {	1028	sub condvar {
819	bless \my $flag, "AnyEvent::Base::CondVar"	1029	bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, AnyEvent::CondVar::
820	}
821
822	sub AnyEvent::Base::CondVar::broadcast {
823	${$_[0]}++;
824	}
825
826	sub AnyEvent::Base::CondVar::wait {
827	AnyEvent->one_event while !${$_[0]};
828	}	1030	}
829		1031
830	# default implementation for ->signal	1032	# default implementation for ->signal
831		1033
832	our %SIG_CB;	1034	our %SIG_CB;
…		…
848	sub AnyEvent::Base::Signal::DESTROY {	1050	sub AnyEvent::Base::Signal::DESTROY {
849	my ($signal, $cb) = @{$_[0]};	1051	my ($signal, $cb) = @{$_[0]};
850		1052
851	delete $SIG_CB{$signal}{$cb};	1053	delete $SIG_CB{$signal}{$cb};
852		1054
853	$SIG{$signal} = 'DEFAULT' unless keys %{ $SIG_CB{$signal} };	1055	delete $SIG{$signal} unless keys %{ $SIG_CB{$signal} };
854	}	1056	}
855		1057
856	# default implementation for ->child	1058	# default implementation for ->child
857		1059
858	our %PID_CB;	1060	our %PID_CB;
…		…
885	or Carp::croak "required option 'pid' is missing";	1087	or Carp::croak "required option 'pid' is missing";
886		1088
887	$PID_CB{$pid}{$arg{cb}} = $arg{cb};	1089	$PID_CB{$pid}{$arg{cb}} = $arg{cb};
888		1090
889	unless ($WNOHANG) {	1091	unless ($WNOHANG) {
890	$WNOHANG = eval { require POSIX; &POSIX::WNOHANG } \|\| 1;	1092	$WNOHANG = eval { local $SIG{__DIE__}; require POSIX; &POSIX::WNOHANG } \|\| 1;
891	}	1093	}
892		1094
893	unless ($CHLD_W) {	1095	unless ($CHLD_W) {
894	$CHLD_W = AnyEvent->signal (signal => 'CHLD', cb => \&_sigchld);	1096	$CHLD_W = AnyEvent->signal (signal => 'CHLD', cb => \&_sigchld);
895	# child could be a zombie already, so make at least one round	1097	# child could be a zombie already, so make at least one round
…		…
905	delete $PID_CB{$pid}{$cb};	1107	delete $PID_CB{$pid}{$cb};
906	delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };	1108	delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };
907		1109
908	undef $CHLD_W unless keys %PID_CB;	1110	undef $CHLD_W unless keys %PID_CB;
909	}	1111	}
		1112
		1113	package AnyEvent::CondVar;
		1114
		1115	our @ISA = AnyEvent::CondVar::Base::;
		1116
		1117	package AnyEvent::CondVar::Base;
		1118
		1119	use overload
		1120	'&{}' => sub { my $self = shift; sub { $self->send (@_) } },
		1121	fallback => 1;
		1122
		1123	sub _send {
		1124	# nop
		1125	}
		1126
		1127	sub send {
		1128	my $cv = shift;
		1129	$cv->{_ae_sent} = [@_];
		1130	(delete $cv->{_ae_cb})->($cv) if $cv->{_ae_cb};
		1131	$cv->_send;
		1132	}
		1133
		1134	sub croak {
		1135	$_[0]{_ae_croak} = $_[1];
		1136	$_[0]->send;
		1137	}
		1138
		1139	sub ready {
		1140	$_[0]{_ae_sent}
		1141	}
		1142
		1143	sub _wait {
		1144	AnyEvent->one_event while !$_[0]{_ae_sent};
		1145	}
		1146
		1147	sub recv {
		1148	$_[0]->_wait;
		1149
		1150	Carp::croak $_[0]{_ae_croak} if $_[0]{_ae_croak};
		1151	wantarray ? @{ $_[0]{_ae_sent} } : $_[0]{_ae_sent}[0]
		1152	}
		1153
		1154	sub cb {
		1155	$_[0]{_ae_cb} = $_[1] if @_ > 1;
		1156	$_[0]{_ae_cb}
		1157	}
		1158
		1159	sub begin {
		1160	++$_[0]{_ae_counter};
		1161	$_[0]{_ae_end_cb} = $_[1] if @_ > 1;
		1162	}
		1163
		1164	sub end {
		1165	return if --$_[0]{_ae_counter};
		1166	&{ $_[0]{_ae_end_cb} \|\| sub { $_[0]->send } };
		1167	}
		1168
		1169	# undocumented/compatibility with pre-3.4
		1170	*broadcast = \&send;
		1171	*wait = \&_wait;
910		1172
911	=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE	1173	=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE
912		1174
913	This is an advanced topic that you do not normally need to use AnyEvent in	1175	This is an advanced topic that you do not normally need to use AnyEvent in
914	a module. This section is only of use to event loop authors who want to	1176	a module. This section is only of use to event loop authors who want to
…		…
968	C<PERL_ANYEVENT_MODEL>.	1230	C<PERL_ANYEVENT_MODEL>.
969		1231
970	When set to C<2> or higher, cause AnyEvent to report to STDERR which event	1232	When set to C<2> or higher, cause AnyEvent to report to STDERR which event
971	model it chooses.	1233	model it chooses.
972		1234
		1235	=item C<PERL_ANYEVENT_STRICT>
		1236
		1237	AnyEvent does not do much argument checking by default, as thorough
		1238	argument checking is very costly. Setting this variable to a true value
		1239	will cause AnyEvent to load C<AnyEvent::Strict> and then to thoroughly
		1240	check the arguments passed to most method calls. If it finds any problems
		1241	it will croak.
		1242
		1243	In other words, enables "strict" mode.
		1244
		1245	Unlike C<use strict> it is definitely recommended ot keep it off in
		1246	production.
		1247
973	=item C<PERL_ANYEVENT_MODEL>	1248	=item C<PERL_ANYEVENT_MODEL>
974		1249
975	This can be used to specify the event model to be used by AnyEvent, before	1250	This can be used to specify the event model to be used by AnyEvent, before
976	autodetection and -probing kicks in. It must be a string consisting	1251	auto detection and -probing kicks in. It must be a string consisting
977	entirely of ASCII letters. The string C<AnyEvent::Impl::> gets prepended	1252	entirely of ASCII letters. The string C<AnyEvent::Impl::> gets prepended
978	and the resulting module name is loaded and if the load was successful,	1253	and the resulting module name is loaded and if the load was successful,
979	used as event model. If it fails to load AnyEvent will proceed with	1254	used as event model. If it fails to load AnyEvent will proceed with
980	autodetection and -probing.	1255	auto detection and -probing.
981		1256
982	This functionality might change in future versions.	1257	This functionality might change in future versions.
983		1258
984	For example, to force the pure perl model (L<AnyEvent::Impl::Perl>) you	1259	For example, to force the pure perl model (L<AnyEvent::Impl::Perl>) you
985	could start your program like this:	1260	could start your program like this:
986		1261
987	PERL_ANYEVENT_MODEL=Perl perl ...	1262	PERL_ANYEVENT_MODEL=Perl perl ...
		1263
		1264	=item C<PERL_ANYEVENT_PROTOCOLS>
		1265
		1266	Used by both L<AnyEvent::DNS> and L<AnyEvent::Socket> to determine preferences
		1267	for IPv4 or IPv6. The default is unspecified (and might change, or be the result
		1268	of auto probing).
		1269
		1270	Must be set to a comma-separated list of protocols or address families,
		1271	current supported: C<ipv4> and C<ipv6>. Only protocols mentioned will be
		1272	used, and preference will be given to protocols mentioned earlier in the
		1273	list.
		1274
		1275	This variable can effectively be used for denial-of-service attacks
		1276	against local programs (e.g. when setuid), although the impact is likely
		1277	small, as the program has to handle connection errors already-
		1278
		1279	Examples: C<PERL_ANYEVENT_PROTOCOLS=ipv4,ipv6> - prefer IPv4 over IPv6,
		1280	but support both and try to use both. C<PERL_ANYEVENT_PROTOCOLS=ipv4>
		1281	- only support IPv4, never try to resolve or contact IPv6
		1282	addresses. C<PERL_ANYEVENT_PROTOCOLS=ipv6,ipv4> support either IPv4 or
		1283	IPv6, but prefer IPv6 over IPv4.
		1284
		1285	=item C<PERL_ANYEVENT_EDNS0>
		1286
		1287	Used by L<AnyEvent::DNS> to decide whether to use the EDNS0 extension
		1288	for DNS. This extension is generally useful to reduce DNS traffic, but
		1289	some (broken) firewalls drop such DNS packets, which is why it is off by
		1290	default.
		1291
		1292	Setting this variable to C<1> will cause L<AnyEvent::DNS> to announce
		1293	EDNS0 in its DNS requests.
		1294
		1295	=item C<PERL_ANYEVENT_MAX_FORKS>
		1296
		1297	The maximum number of child processes that C<AnyEvent::Util::fork_call>
		1298	will create in parallel.
988		1299
989	=back	1300	=back
990		1301
991	=head1 EXAMPLE PROGRAM	1302	=head1 EXAMPLE PROGRAM
992		1303
…		…
1003	poll => 'r',	1314	poll => 'r',
1004	cb => sub {	1315	cb => sub {
1005	warn "io event <$_[0]>\n"; # will always output <r>	1316	warn "io event <$_[0]>\n"; # will always output <r>
1006	chomp (my $input = <STDIN>); # read a line	1317	chomp (my $input = <STDIN>); # read a line
1007	warn "read: $input\n"; # output what has been read	1318	warn "read: $input\n"; # output what has been read
1008	$cv->broadcast if $input =~ /^q/i; # quit program if /^q/i	1319	$cv->send if $input =~ /^q/i; # quit program if /^q/i
1009	},	1320	},
1010	);	1321	);
1011		1322
1012	my $time_watcher; # can only be used once	1323	my $time_watcher; # can only be used once
1013		1324
…		…
1018	});	1329	});
1019	}	1330	}
1020		1331
1021	new_timer; # create first timer	1332	new_timer; # create first timer
1022		1333
1023	$cv->wait; # wait until user enters /^q/i	1334	$cv->recv; # wait until user enters /^q/i
1024		1335
1025	=head1 REAL-WORLD EXAMPLE	1336	=head1 REAL-WORLD EXAMPLE
1026		1337
1027	Consider the L<Net::FCP> module. It features (among others) the following	1338	Consider the L<Net::FCP> module. It features (among others) the following
1028	API calls, which are to freenet what HTTP GET requests are to http:	1339	API calls, which are to freenet what HTTP GET requests are to http:
…		…
1078	syswrite $txn->{fh}, $txn->{request}	1389	syswrite $txn->{fh}, $txn->{request}
1079	or die "connection or write error";	1390	or die "connection or write error";
1080	$txn->{w} = AnyEvent->io (fh => $txn->{fh}, poll => 'r', cb => sub { $txn->fh_ready_r });	1391	$txn->{w} = AnyEvent->io (fh => $txn->{fh}, poll => 'r', cb => sub { $txn->fh_ready_r });
1081		1392
1082	Again, C<fh_ready_r> waits till all data has arrived, and then stores the	1393	Again, C<fh_ready_r> waits till all data has arrived, and then stores the
1083	result and signals any possible waiters that the request ahs finished:	1394	result and signals any possible waiters that the request has finished:
1084		1395
1085	sysread $txn->{fh}, $txn->{buf}, length $txn->{$buf};	1396	sysread $txn->{fh}, $txn->{buf}, length $txn->{$buf};
1086		1397
1087	if (end-of-file or data complete) {	1398	if (end-of-file or data complete) {
1088	$txn->{result} = $txn->{buf};	1399	$txn->{result} = $txn->{buf};
1089	$txn->{finished}->broadcast;	1400	$txn->{finished}->send;
1090	$txb->{cb}->($txn) of $txn->{cb}; # also call callback	1401	$txb->{cb}->($txn) of $txn->{cb}; # also call callback
1091	}	1402	}
1092		1403
1093	The C<result> method, finally, just waits for the finished signal (if the	1404	The C<result> method, finally, just waits for the finished signal (if the
1094	request was already finished, it doesn't wait, of course, and returns the	1405	request was already finished, it doesn't wait, of course, and returns the
1095	data:	1406	data:
1096		1407
1097	$txn->{finished}->wait;	1408	$txn->{finished}->recv;
1098	return $txn->{result};	1409	return $txn->{result};
1099		1410
1100	The actual code goes further and collects all errors (C<die>s, exceptions)	1411	The actual code goes further and collects all errors (C<die>s, exceptions)
1101	that occured during request processing. The C<result> method detects	1412	that occurred during request processing. The C<result> method detects
1102	whether an exception as thrown (it is stored inside the $txn object)	1413	whether an exception as thrown (it is stored inside the $txn object)
1103	and just throws the exception, which means connection errors and other	1414	and just throws the exception, which means connection errors and other
1104	problems get reported tot he code that tries to use the result, not in a	1415	problems get reported tot he code that tries to use the result, not in a
1105	random callback.	1416	random callback.
1106		1417
…		…
1137		1448
1138	my $quit = AnyEvent->condvar;	1449	my $quit = AnyEvent->condvar;
1139		1450
1140	$fcp->txn_client_get ($url)->cb (sub {	1451	$fcp->txn_client_get ($url)->cb (sub {
1141	...	1452	...
1142	$quit->broadcast;	1453	$quit->send;
1143	});	1454	});
1144		1455
1145	$quit->wait;	1456	$quit->recv;
1146		1457
1147		1458
1148	=head1 BENCHMARKS	1459	=head1 BENCHMARKS
1149		1460
1150	To give you an idea of the performance and overheads that AnyEvent adds	1461	To give you an idea of the performance and overheads that AnyEvent adds
…		…
1152	of various event loops I prepared some benchmarks.	1463	of various event loops I prepared some benchmarks.
1153		1464
1154	=head2 BENCHMARKING ANYEVENT OVERHEAD	1465	=head2 BENCHMARKING ANYEVENT OVERHEAD
1155		1466
1156	Here is a benchmark of various supported event models used natively and	1467	Here is a benchmark of various supported event models used natively and
1157	through anyevent. The benchmark creates a lot of timers (with a zero	1468	through AnyEvent. The benchmark creates a lot of timers (with a zero
1158	timeout) and I/O watchers (watching STDOUT, a pty, to become writable,	1469	timeout) and I/O watchers (watching STDOUT, a pty, to become writable,
1159	which it is), lets them fire exactly once and destroys them again.	1470	which it is), lets them fire exactly once and destroys them again.
1160		1471
1161	Source code for this benchmark is found as F<eg/bench> in the AnyEvent	1472	Source code for this benchmark is found as F<eg/bench> in the AnyEvent
1162	distribution.	1473	distribution.
…		…
1179	all watchers, to avoid adding memory overhead. That means closure creation	1490	all watchers, to avoid adding memory overhead. That means closure creation
1180	and memory usage is not included in the figures.	1491	and memory usage is not included in the figures.
1181		1492
1182	I<invoke> is the time, in microseconds, used to invoke a simple	1493	I<invoke> is the time, in microseconds, used to invoke a simple
1183	callback. The callback simply counts down a Perl variable and after it was	1494	callback. The callback simply counts down a Perl variable and after it was
1184	invoked "watcher" times, it would C<< ->broadcast >> a condvar once to	1495	invoked "watcher" times, it would C<< ->send >> a condvar once to
1185	signal the end of this phase.	1496	signal the end of this phase.
1186		1497
1187	I<destroy> is the time, in microseconds, that it takes to destroy a single	1498	I<destroy> is the time, in microseconds, that it takes to destroy a single
1188	watcher.	1499	watcher.
1189		1500
…		…
1285		1596
1286	=back	1597	=back
1287		1598
1288	=head2 BENCHMARKING THE LARGE SERVER CASE	1599	=head2 BENCHMARKING THE LARGE SERVER CASE
1289		1600
1290	This benchmark atcually benchmarks the event loop itself. It works by	1601	This benchmark actually benchmarks the event loop itself. It works by
1291	creating a number of "servers": each server consists of a socketpair, a	1602	creating a number of "servers": each server consists of a socket pair, a
1292	timeout watcher that gets reset on activity (but never fires), and an I/O	1603	timeout watcher that gets reset on activity (but never fires), and an I/O
1293	watcher waiting for input on one side of the socket. Each time the socket	1604	watcher waiting for input on one side of the socket. Each time the socket
1294	watcher reads a byte it will write that byte to a random other "server".	1605	watcher reads a byte it will write that byte to a random other "server".
1295		1606
1296	The effect is that there will be a lot of I/O watchers, only part of which	1607	The effect is that there will be a lot of I/O watchers, only part of which
1297	are active at any one point (so there is a constant number of active	1608	are active at any one point (so there is a constant number of active
1298	fds for each loop iterstaion, but which fds these are is random). The	1609	fds for each loop iteration, but which fds these are is random). The
1299	timeout is reset each time something is read because that reflects how	1610	timeout is reset each time something is read because that reflects how
1300	most timeouts work (and puts extra pressure on the event loops).	1611	most timeouts work (and puts extra pressure on the event loops).
1301		1612
1302	In this benchmark, we use 10000 socketpairs (20000 sockets), of which 100	1613	In this benchmark, we use 10000 socket pairs (20000 sockets), of which 100
1303	(1%) are active. This mirrors the activity of large servers with many	1614	(1%) are active. This mirrors the activity of large servers with many
1304	connections, most of which are idle at any one point in time.	1615	connections, most of which are idle at any one point in time.
1305		1616
1306	Source code for this benchmark is found as F<eg/bench2> in the AnyEvent	1617	Source code for this benchmark is found as F<eg/bench2> in the AnyEvent
1307	distribution.	1618	distribution.
…		…
1309	=head3 Explanation of the columns	1620	=head3 Explanation of the columns
1310		1621
1311	I<sockets> is the number of sockets, and twice the number of "servers" (as	1622	I<sockets> is the number of sockets, and twice the number of "servers" (as
1312	each server has a read and write socket end).	1623	each server has a read and write socket end).
1313		1624
1314	I<create> is the time it takes to create a socketpair (which is	1625	I<create> is the time it takes to create a socket pair (which is
1315	nontrivial) and two watchers: an I/O watcher and a timeout watcher.	1626	nontrivial) and two watchers: an I/O watcher and a timeout watcher.
1316		1627
1317	I<request>, the most important value, is the time it takes to handle a	1628	I<request>, the most important value, is the time it takes to handle a
1318	single "request", that is, reading the token from the pipe and forwarding	1629	single "request", that is, reading the token from the pipe and forwarding
1319	it to another server. This includes deleting the old timeout and creating	1630	it to another server. This includes deleting the old timeout and creating
…		…
1392	speed most when you have lots of watchers, not when you only have a few of	1703	speed most when you have lots of watchers, not when you only have a few of
1393	them).	1704	them).
1394		1705
1395	EV is again fastest.	1706	EV is again fastest.
1396		1707
1397	Perl again comes second. It is noticably faster than the C-based event	1708	Perl again comes second. It is noticeably faster than the C-based event
1398	loops Event and Glib, although the difference is too small to really	1709	loops Event and Glib, although the difference is too small to really
1399	matter.	1710	matter.
1400		1711
1401	POE also performs much better in this case, but is is still far behind the	1712	POE also performs much better in this case, but is is still far behind the
1402	others.	1713	others.
…		…
1431	specified in the variable.	1742	specified in the variable.
1432		1743
1433	You can make AnyEvent completely ignore this variable by deleting it	1744	You can make AnyEvent completely ignore this variable by deleting it
1434	before the first watcher gets created, e.g. with a C<BEGIN> block:	1745	before the first watcher gets created, e.g. with a C<BEGIN> block:
1435		1746
1436	BEGIN { delete $ENV{PERL_ANYEVENT_MODEL} }	1747	BEGIN { delete $ENV{PERL_ANYEVENT_MODEL} }
1437		1748
1438	use AnyEvent;	1749	use AnyEvent;
1439		1750
1440	Similar considerations apply to $ENV{PERL_ANYEVENT_VERBOSE}, as that can	1751	Similar considerations apply to $ENV{PERL_ANYEVENT_VERBOSE}, as that can
1441	be used to probe what backend is used and gain other information (which is	1752	be used to probe what backend is used and gain other information (which is
1442	probably even less useful to an attacker than PERL_ANYEVENT_MODEL).	1753	probably even less useful to an attacker than PERL_ANYEVENT_MODEL), and
		1754	$ENV{PERL_ANYEGENT_STRICT}.
		1755
		1756
		1757	=head1 BUGS
		1758
		1759	Perl 5.8 has numerous memleaks that sometimes hit this module and are hard
		1760	to work around. If you suffer from memleaks, first upgrade to Perl 5.10
		1761	and check wether the leaks still show up. (Perl 5.10.0 has other annoying
		1762	mamleaks, such as leaking on C<map> and C<grep> but it is usually not as
		1763	pronounced).
1443		1764
1444		1765
1445	=head1 SEE ALSO	1766	=head1 SEE ALSO
		1767
		1768	Utility functions: L<AnyEvent::Util>.
1446		1769
1447	Event modules: L<EV>, L<EV::Glib>, L<Glib::EV>, L<Event>, L<Glib::Event>,	1770	Event modules: L<EV>, L<EV::Glib>, L<Glib::EV>, L<Event>, L<Glib::Event>,
1448	L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>.	1771	L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>.
1449		1772
1450	Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>,	1773	Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>,
1451	L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>,	1774	L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>,
1452	L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>,	1775	L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>,
1453	L<AnyEvent::Impl::POE>.	1776	L<AnyEvent::Impl::POE>.
1454		1777
		1778	Non-blocking file handles, sockets, TCP clients and
		1779	servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>.
		1780
		1781	Asynchronous DNS: L<AnyEvent::DNS>.
		1782
1455	Coroutine support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>, L<Coro::Event>,	1783	Coroutine support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>, L<Coro::Event>,
1456		1784
1457	Nontrivial usage examples: L<Net::FCP>, L<Net::XMPP2>.	1785	Nontrivial usage examples: L<Net::FCP>, L<Net::XMPP2>, L<AnyEvent::DNS>.
1458		1786
1459		1787
1460	=head1 AUTHOR	1788	=head1 AUTHOR
1461		1789
1462	Marc Lehmann <schmorp@schmorp.de>	1790	Marc Lehmann <schmorp@schmorp.de>
1463	http://home.schmorp.de/	1791	http://home.schmorp.de/
1464		1792
1465	=cut	1793	=cut
1466		1794
1467	1	1795	1
1468		1796

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Comparing AnyEvent/lib/AnyEvent.pm (file contents): Revision 1.112 by root, Sat May 10 01:04:42 2008 UTC vs. Revision 1.175 by root, Sun Jul 27 08:43:32 2008 UTC

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Comparing AnyEvent/lib/AnyEvent.pm (file contents):
Revision 1.112 by root, Sat May 10 01:04:42 2008 UTC vs.
Revision 1.175 by root, Sun Jul 27 08:43:32 2008 UTC