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

Comparing AnyEvent/lib/AnyEvent.pm (file contents):
Revision 1.17 by root, Fri Nov 24 14:40:13 2006 UTC vs.
Revision 1.61 by root, Fri Apr 25 01:55:25 2008 UTC

…		…
1	=head1 NAME	1	=head1 NAME
2		2
3	AnyEvent - provide framework for multiple event loops	3	AnyEvent - provide framework for multiple event loops
4		4
5	Event, Coro, Glib, Tk, Perl - various supported event loops	5	EV, Event, Coro::EV, Coro::Event, Glib, Tk, Perl, Event::Lib, Qt, POE - various supported event loops
6		6
7	=head1 SYNOPSIS	7	=head1 SYNOPSIS
8		8
9	use AnyEvent;	9	use AnyEvent;
10		10
14		14
15	my $w = AnyEvent->timer (after => $seconds, cb => sub {	15	my $w = AnyEvent->timer (after => $seconds, cb => sub {
16	...	16	...
17	});	17	});
18		18
19	my $w = AnyEvent->condvar; # stores wether a condition was flagged	19	my $w = AnyEvent->condvar; # stores whether a condition was flagged
20	$w->wait; # enters "main loop" till $condvar gets ->broadcast	20	$w->wait; # enters "main loop" till $condvar gets ->broadcast
21	$w->broadcast; # wake up current and all future wait's	21	$w->broadcast; # wake up current and all future wait's
		22
		23	=head1 WHY YOU SHOULD USE THIS MODULE (OR NOT)
		24
		25	Glib, POE, IO::Async, Event... CPAN offers event models by the dozen
		26	nowadays. So what is different about AnyEvent?
		27
		28	Executive Summary: AnyEvent is I<compatible>, AnyEvent is I<free of
		29	policy> and AnyEvent is I<small and efficient>.
		30
		31	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
		33	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,
		35	only one event loop can be active at the same time in a process. AnyEvent
		36	helps hiding the differences between those event loops.
		37
		38	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
		40	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
		42	model you use.
		43
		44	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
		46	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
		48	isn't itself. What's worse, all the potential users of your module are
		49	I<also> forced to use the same event loop you use.
		50
		51	AnyEvent is different: AnyEvent + POE works fine. AnyEvent + Glib works
		52	fine. AnyEvent + Tk works fine etc. etc. but none of these work together
		53	with the rest: POE + IO::Async? no go. Tk + Event? no go. Again: if
		54	your module uses one of those, every user of your module has to use it,
		55	too. But if your module uses AnyEvent, it works transparently with all
		56	event models it supports (including stuff like POE and IO::Async, as long
		57	as those use one of the supported event loops. It is trivial to add new
		58	event loops to AnyEvent, too, so it is future-proof).
		59
		60	In addition to being free of having to use I<the one and only true event
		61	model>, AnyEvent also is free of bloat and policy: with POE or similar
		62	modules, you get an enourmous 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
		64	offering the functionality that is necessary, in as thin as a wrapper as
		65	technically possible.
		66
		67	Of course, if you 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
		69	model, you should I<not> use this module.
		70
22		71
23	=head1 DESCRIPTION	72	=head1 DESCRIPTION
24		73
25	L<AnyEvent> provides an identical interface to multiple event loops. This	74	L<AnyEvent> provides an identical interface to multiple event loops. This
26	allows module authors to utilise an event loop without forcing module	75	allows module authors to utilise an event loop without forcing module
27	users to use the same event loop (as only a single event loop can coexist	76	users to use the same event loop (as only a single event loop can coexist
28	peacefully at any one time).	77	peacefully at any one time).
29		78
30	The interface itself is vaguely similar but not identical to the Event	79	The interface itself is vaguely similar, but not identical to the L<Event>
31	module.	80	module.
32		81
33	On the first call of any method, the module tries to detect the currently	82	During the first call of any watcher-creation method, the module tries
34	loaded event loop by probing wether any of the following modules is	83	to detect the currently loaded event loop by probing whether one of the
35	loaded: L<Coro::Event>, L<Event>, L<Glib>, L<Tk>. The first one found is	84	following modules is already loaded: L<Coro::EV>, L<Coro::Event>, L<EV>,
36	used. If none is found, the module tries to load these modules in the	85	L<Event>, L<Glib>, L<Tk>, L<AnyEvent::Impl::Perl>, L<Event::Lib>, L<Qt>,
37	order given. The first one that could be successfully loaded will be	86	L<POE>. The first one found is used. If none are found, the module tries
38	used. If still none could be found, AnyEvent will fall back to a pure-perl	87	to load these modules (excluding Event::Lib, Qt and POE as the pure perl
39	event loop, which is also not very efficient.	88	adaptor should always succeed) in the order given. The first one that can
		89	be successfully loaded will be used. If, after this, still none could be
		90	found, AnyEvent will fall back to a pure-perl event loop, which is not
		91	very efficient, but should work everywhere.
40		92
41	Because AnyEvent first checks for modules that are already loaded, loading	93	Because AnyEvent first checks for modules that are already loaded, loading
42	an Event model explicitly before first using AnyEvent will likely make	94	an event model explicitly before first using AnyEvent will likely make
43	that model the default. For example:	95	that model the default. For example:
44		96
45	use Tk;	97	use Tk;
46	use AnyEvent;	98	use AnyEvent;
47		99
48	# .. AnyEvent will likely default to Tk	100	# .. AnyEvent will likely default to Tk
		101
		102	The I<likely> means that, if any module loads another event model and
		103	starts using it, all bets are off. Maybe you should tell their authors to
		104	use AnyEvent so their modules work together with others seamlessly...
49		105
50	The pure-perl implementation of AnyEvent is called	106	The pure-perl implementation of AnyEvent is called
51	C<AnyEvent::Impl::Perl>. Like other event modules you can load it	107	C<AnyEvent::Impl::Perl>. Like other event modules you can load it
52	explicitly.	108	explicitly.
53		109
…		…
56	AnyEvent has the central concept of a I<watcher>, which is an object that	112	AnyEvent has the central concept of a I<watcher>, which is an object that
57	stores relevant data for each kind of event you are waiting for, such as	113	stores relevant data for each kind of event you are waiting for, such as
58	the callback to call, the filehandle to watch, etc.	114	the callback to call, the filehandle to watch, etc.
59		115
60	These watchers are normal Perl objects with normal Perl lifetime. After	116	These watchers are normal Perl objects with normal Perl lifetime. After
61	creating a watcher it will immediately "watch" for events and invoke	117	creating a watcher it will immediately "watch" for events and invoke the
		118	callback when the event occurs (of course, only when the event model
		119	is in control).
		120
62	the callback. To disable the watcher you have to destroy it (e.g. by	121	To disable the watcher you have to destroy it (e.g. by setting the
63	setting the variable that stores it to C<undef> or otherwise deleting all	122	variable you store it in to C<undef> or otherwise deleting all references
64	references to it).	123	to it).
65		124
66	All watchers are created by calling a method on the C<AnyEvent> class.	125	All watchers are created by calling a method on the C<AnyEvent> class.
67		126
		127	Many watchers either are used with "recursion" (repeating timers for
		128	example), or need to refer to their watcher object in other ways.
		129
		130	An any way to achieve that is this pattern:
		131
		132	my $w; $w = AnyEvent->type (arg => value ..., cb => sub {
		133	# you can use $w here, for example to undef it
		134	undef $w;
		135	});
		136
		137	Note that C<my $w; $w => combination. This is necessary because in Perl,
		138	my variables are only visible after the statement in which they are
		139	declared.
		140
68	=head2 IO WATCHERS	141	=head2 IO WATCHERS
69		142
70	You can create I/O watcher by calling the C<< AnyEvent->io >> method with	143	You can create an I/O watcher by calling the C<< AnyEvent->io >> method
71	the following mandatory arguments:	144	with the following mandatory key-value pairs as arguments:
72		145
73	C<fh> the Perl I<filehandle> (not filedescriptor) to watch for	146	C<fh> the Perl I<file handle> (I<not> file descriptor) to watch for
74	events. C<poll> must be a string that is either C<r> or C<w>, that creates	147	events. C<poll> must be a string that is either C<r> or C<w>, which
75	a watcher waiting for "r"eadable or "w"ritable events. C<cb> teh callback	148	creates a watcher waiting for "r"eadable or "w"ritable events,
76	to invoke everytime the filehandle becomes ready.	149	respectively. C<cb> is the callback to invoke each time the file handle
		150	becomes ready.
77		151
78	Only one io watcher per C<fh> and C<poll> combination is allowed (i.e. on	152	As long as the I/O watcher exists it will keep the file descriptor or a
79	a socket you can have one r + one w, not any more (limitation comes from	153	copy of it alive/open.
80	Tk - if you are sure you are not using Tk this limitation is gone).
81		154
82	Filehandles will be kept alive, so as long as the watcher exists, the	155	It is not allowed to close a file handle as long as any watcher is active
83	filehandle exists, too.	156	on the underlying file descriptor.
		157
		158	Some event loops issue spurious readyness notifications, so you should
		159	always use non-blocking calls when reading/writing from/to your file
		160	handles.
84		161
85	Example:	162	Example:
86		163
87	# wait for readability of STDIN, then read a line and disable the watcher	164	# wait for readability of STDIN, then read a line and disable the watcher
88	my $w; $w = AnyEvent->io (fh => \*STDIN, poll => 'r', cb => sub {	165	my $w; $w = AnyEvent->io (fh => \*STDIN, poll => 'r', cb => sub {
89	chomp (my $input = <STDIN>);	166	chomp (my $input = <STDIN>);
90	warn "read: $input\n";	167	warn "read: $input\n";
91	undef $w;	168	undef $w;
92	});	169	});
93		170
94	=head2 TIMER WATCHERS	171	=head2 TIME WATCHERS
95		172
96	You can create a timer watcher by calling the C<< AnyEvent->timer >>	173	You can create a time watcher by calling the C<< AnyEvent->timer >>
97	method with the following mandatory arguments:	174	method with the following mandatory arguments:
98		175
99	C<after> after how many seconds (fractions are supported) should the timer	176	C<after> specifies after how many seconds (fractional values are
100	activate. C<cb> the callback to invoke.	177	supported) should the timer activate. C<cb> the callback to invoke in that
		178	case.
101		179
102	The timer callback will be invoked at most once: if you want a repeating	180	The timer callback will be invoked at most once: if you want a repeating
103	timer you have to create a new watcher (this is a limitation by both Tk	181	timer you have to create a new watcher (this is a limitation by both Tk
104	and Glib).	182	and Glib).
105		183
…		…
109	my $w = AnyEvent->timer (after => 7.7, cb => sub {	187	my $w = AnyEvent->timer (after => 7.7, cb => sub {
110	warn "timeout\n";	188	warn "timeout\n";
111	});	189	});
112		190
113	# to cancel the timer:	191	# to cancel the timer:
114	undef $w	192	undef $w;
115		193
		194	Example 2:
		195
		196	# fire an event after 0.5 seconds, then roughly every second
		197	my $w;
		198
		199	my $cb = sub {
		200	# cancel the old timer while creating a new one
		201	$w = AnyEvent->timer (after => 1, cb => $cb);
		202	};
		203
		204	# start the "loop" by creating the first watcher
		205	$w = AnyEvent->timer (after => 0.5, cb => $cb);
		206
		207	=head3 TIMING ISSUES
		208
		209	There are two ways to handle timers: based on real time (relative, "fire
		210	in 10 seconds") and based on wallclock time (absolute, "fire at 12
		211	o'clock").
		212
		213	While most event loops expect timers to specified in a relative way, they
		214	use absolute time internally. This makes a difference when your clock
		215	"jumps", for example, when ntp decides to set your clock backwards from
		216	the wrong date of 2014-01-01 to 2008-01-01, a watcher that is supposed to
		217	fire "after" a second might actually take six years to finally fire.
		218
		219	AnyEvent cannot compensate for this. The only event loop that is conscious
		220	about these issues is L<EV>, which offers both relative (ev_timer, based
		221	on true relative time) and absolute (ev_periodic, based on wallclock time)
		222	timers.
		223
		224	AnyEvent always prefers relative timers, if available, matching the
		225	AnyEvent API.
		226
		227	=head2 SIGNAL WATCHERS
		228
		229	You can watch for signals using a signal watcher, C<signal> is the signal
		230	I<name> without any C<SIG> prefix, C<cb> is the Perl callback to
		231	be invoked whenever a signal occurs.
		232
		233	Multiple signal occurances can be clumped together into one callback
		234	invocation, and callback invocation will be synchronous. synchronous means
		235	that it might take a while until the signal gets handled by the process,
		236	but it is guarenteed not to interrupt any other callbacks.
		237
		238	The main advantage of using these watchers is that you can share a signal
		239	between multiple watchers.
		240
		241	This watcher might use C<%SIG>, so programs overwriting those signals
		242	directly will likely not work correctly.
		243
		244	Example: exit on SIGINT
		245
		246	my $w = AnyEvent->signal (signal => "INT", cb => sub { exit 1 });
		247
		248	=head2 CHILD PROCESS WATCHERS
		249
		250	You can also watch on a child process exit and catch its exit status.
		251
		252	The child process is specified by the C<pid> argument (if set to C<0>, it
		253	watches for any child process exit). The watcher will trigger as often
		254	as status change for the child are received. This works by installing a
		255	signal handler for C<SIGCHLD>. The callback will be called with the pid
		256	and exit status (as returned by waitpid).
		257
		258	Example: wait for pid 1333
		259
		260	my $w = AnyEvent->child (
		261	pid => 1333,
		262	cb => sub {
		263	my ($pid, $status) = @_;
		264	warn "pid $pid exited with status $status";
		265	},
		266	);
		267
116	=head2 CONDITION WATCHERS	268	=head2 CONDITION VARIABLES
117		269
118	Condition watchers can be created by calling the C<< AnyEvent->condvar >>	270	Condition variables can be created by calling the C<< AnyEvent->condvar >>
119	method without any arguments.	271	method without any arguments.
120		272
121	A condition watcher watches for a condition - precisely that the C<<	273	A condition variable waits for a condition - precisely that the C<<
122	->broadcast >> method has been called.	274	->broadcast >> method has been called.
123		275
124	The watcher has only two methods:	276	They are very useful to signal that a condition has been fulfilled, for
		277	example, if you write a module that does asynchronous http requests,
		278	then a condition variable would be the ideal candidate to signal the
		279	availability of results.
		280
		281	You can also use condition variables to block your main program until
		282	an event occurs - for example, you could C<< ->wait >> in your main
		283	program until the user clicks the Quit button in your app, which would C<<
		284	->broadcast >> the "quit" event.
		285
		286	Note that condition variables recurse into the event loop - if you have
		287	two pirces of code that call C<< ->wait >> in a round-robbin fashion, you
		288	lose. Therefore, condition variables are good to export to your caller, but
		289	you should avoid making a blocking wait yourself, at least in callbacks,
		290	as this asks for trouble.
		291
		292	This object has two methods:
125		293
126	=over 4	294	=over 4
127		295
128	=item $cv->wait	296	=item $cv->wait
129		297
130	Wait (blocking if necessary) until the C<< ->broadcast >> method has been	298	Wait (blocking if necessary) until the C<< ->broadcast >> method has been
131	called on c<$cv>, while servicing other watchers normally.	299	called on c<$cv>, while servicing other watchers normally.
132		300
133	Not all event models support a blocking wait - some die in that case, so
134	if you are using this from a module, never require a blocking wait, but
135	let the caller decide wether the call will block or not (for example,
136	by coupling condition variables with some kind of request results and
137	supporting callbacks so the caller knows that getting the result will not
138	block, while still suppporting blockign waits if the caller so desires).
139
140	You can only wait once on a condition - additional calls will return	301	You can only wait once on a condition - additional calls will return
141	immediately.	302	immediately.
142		303
		304	Not all event models support a blocking wait - some die in that case
		305	(programs might want to do that to stay interactive), so I<if you are
		306	using this from a module, never require a blocking wait>, but let the
		307	caller decide whether the call will block or not (for example, by coupling
		308	condition variables with some kind of request results and supporting
		309	callbacks so the caller knows that getting the result will not block,
		310	while still suppporting blocking waits if the caller so desires).
		311
		312	Another reason I<never> to C<< ->wait >> in a module is that you cannot
		313	sensibly have two C<< ->wait >>'s in parallel, as that would require
		314	multiple interpreters or coroutines/threads, none of which C<AnyEvent>
		315	can supply (the coroutine-aware backends L<AnyEvent::Impl::CoroEV> and
		316	L<AnyEvent::Impl::CoroEvent> explicitly support concurrent C<< ->wait >>'s
		317	from different coroutines, however).
		318
143	=item $cv->broadcast	319	=item $cv->broadcast
144		320
145	Flag the condition as ready - a running C<< ->wait >> and all further	321	Flag the condition as ready - a running C<< ->wait >> and all further
146	calls to C<wait> will return after this method has been called. If nobody	322	calls to C<wait> will (eventually) return after this method has been
147	is waiting the broadcast will be remembered..	323	called. If nobody is waiting the broadcast will be remembered..
		324
		325	=back
148		326
149	Example:	327	Example:
150		328
151	# wait till the result is ready	329	# wait till the result is ready
152	my $result_ready = AnyEvent->condvar;	330	my $result_ready = AnyEvent->condvar;
153		331
154	# do something such as adding a timer	332	# do something such as adding a timer
155	# or socket watcher the calls $result_ready->broadcast	333	# or socket watcher the calls $result_ready->broadcast
156	# when the "result" is ready.	334	# when the "result" is ready.
		335	# in this case, we simply use a timer:
		336	my $w = AnyEvent->timer (
		337	after => 1,
		338	cb => sub { $result_ready->broadcast },
		339	);
157		340
		341	# this "blocks" (while handling events) till the watcher
		342	# calls broadcast
158	$result_ready->wait;	343	$result_ready->wait;
159		344
160	=back	345	=head1 GLOBAL VARIABLES AND FUNCTIONS
161
162	=head1 GLOBALS
163		346
164	=over 4	347	=over 4
165		348
166	=item $AnyEvent::MODEL	349	=item $AnyEvent::MODEL
167		350
…		…
171	C<AnyEvent::Impl:xxx> modules, but can be any other class in the case	354	C<AnyEvent::Impl:xxx> modules, but can be any other class in the case
172	AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode>).	355	AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode>).
173		356
174	The known classes so far are:	357	The known classes so far are:
175		358
176	AnyEvent::Impl::Coro based on Coro::Event, best choise.	359	AnyEvent::Impl::CoroEV based on Coro::EV, best choice.
		360	AnyEvent::Impl::CoroEvent based on Coro::Event, second best choice.
		361	AnyEvent::Impl::EV based on EV (an interface to libev, best choice).
177	AnyEvent::Impl::Event based on Event, also best choice :)	362	AnyEvent::Impl::Event based on Event, second best choice.
178	AnyEvent::Impl::Glib based on Glib, second-best choice.	363	AnyEvent::Impl::Glib based on Glib, third-best choice.
179	AnyEvent::Impl::Tk based on Tk, very bad choice.	364	AnyEvent::Impl::Tk based on Tk, very bad choice.
180	AnyEvent::Impl::Perl pure-perl implementation, inefficient.	365	AnyEvent::Impl::Perl pure-perl implementation, inefficient but portable.
		366	AnyEvent::Impl::Qt based on Qt, cannot be autoprobed (see its docs).
		367	AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse.
		368	AnyEvent::Impl::POE based on POE, not generic enough for full support.
		369
		370	There is no support for WxWidgets, as WxWidgets has no support for
		371	watching file handles. However, you can use WxWidgets through the
		372	POE Adaptor, as POE has a Wx backend that simply polls 20 times per
		373	second, which was considered to be too horrible to even consider for
		374	AnyEvent. Likewise, other POE backends can be used by Anyevent by using
		375	it's adaptor.
		376
		377	=item AnyEvent::detect
		378
		379	Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model
		380	if necessary. You should only call this function right before you would
		381	have created an AnyEvent watcher anyway, that is, as late as possible at
		382	runtime.
181		383
182	=back	384	=back
183		385
184	=head1 WHAT TO DO IN A MODULE	386	=head1 WHAT TO DO IN A MODULE
185		387
186	As a module author, you should "use AnyEvent" and call AnyEvent methods	388	As a module author, you should C<use AnyEvent> and call AnyEvent methods
187	freely, but you should not load a specific event module or rely on it.	389	freely, but you should not load a specific event module or rely on it.
188		390
189	Be careful when you create watchers in the module body - Anyevent will	391	Be careful when you create watchers in the module body - AnyEvent will
190	decide which event module to use as soon as the first method is called, so	392	decide which event module to use as soon as the first method is called, so
191	by calling AnyEvent in your module body you force the user of your module	393	by calling AnyEvent in your module body you force the user of your module
192	to load the event module first.	394	to load the event module first.
193		395
		396	Never call C<< ->wait >> on a condition variable unless you I<know> that
		397	the C<< ->broadcast >> method has been called on it already. This is
		398	because it will stall the whole program, and the whole point of using
		399	events is to stay interactive.
		400
		401	It is fine, however, to call C<< ->wait >> when the user of your module
		402	requests it (i.e. if you create a http request object ad have a method
		403	called C<results> that returns the results, it should call C<< ->wait >>
		404	freely, as the user of your module knows what she is doing. always).
		405
194	=head1 WHAT TO DO IN THE MAIN PROGRAM	406	=head1 WHAT TO DO IN THE MAIN PROGRAM
195		407
196	There will always be a single main program - the only place that should	408	There will always be a single main program - the only place that should
197	dictate which event model to use.	409	dictate which event model to use.
198		410
199	If it doesn't care, it can just "use AnyEvent" and use it itself, or not	411	If it doesn't care, it can just "use AnyEvent" and use it itself, or not
200	do anything special and let AnyEvent decide which implementation to chose.	412	do anything special (it does not need to be event-based) and let AnyEvent
		413	decide which implementation to chose if some module relies on it.
201		414
202	If the main program relies on a specific event model (for example, in Gtk2	415	If the main program relies on a specific event model. For example, in
203	programs you have to rely on either Glib or Glib::Event), you should load	416	Gtk2 programs you have to rely on the Glib module. You should load the
204	it before loading AnyEvent or any module that uses it, generally, as early	417	event module before loading AnyEvent or any module that uses it: generally
205	as possible. The reason is that modules might create watchers when they	418	speaking, you should load it as early as possible. The reason is that
206	are loaded, and AnyEvent will decide on the event model to use as soon as	419	modules might create watchers when they are loaded, and AnyEvent will
207	it creates watchers, and it might chose the wrong one unless you load the	420	decide on the event model to use as soon as it creates watchers, and it
208	correct one yourself.	421	might chose the wrong one unless you load the correct one yourself.
209		422
210	You can chose to use a rather inefficient pure-perl implementation by	423	You can chose to use a rather inefficient pure-perl implementation by
211	loading the C<AnyEvent::Impl::Perl> module, but letting AnyEvent chose is	424	loading the C<AnyEvent::Impl::Perl> module, which gives you similar
212	generally better.	425	behaviour everywhere, but letting AnyEvent chose is generally better.
213		426
214	=cut	427	=cut
215		428
216	package AnyEvent;	429	package AnyEvent;
217		430
218	no warnings;	431	no warnings;
219	use strict 'vars';	432	use strict;
		433
220	use Carp;	434	use Carp;
221		435
222	our $VERSION = '2.1';	436	our $VERSION = '3.2';
223	our $MODEL;	437	our $MODEL;
224		438
225	our $AUTOLOAD;	439	our $AUTOLOAD;
226	our @ISA;	440	our @ISA;
227		441
228	our $verbose = $ENV{PERL_ANYEVENT_VERBOSE}*1;	442	our $verbose = $ENV{PERL_ANYEVENT_VERBOSE}*1;
229		443
230	our @REGISTRY;	444	our @REGISTRY;
231		445
232	my @models = (	446	my @models = (
		447	[Coro::EV:: => AnyEvent::Impl::CoroEV::],
233	[Coro::Event:: => AnyEvent::Impl::Coro::],	448	[Coro::Event:: => AnyEvent::Impl::CoroEvent::],
		449	[EV:: => AnyEvent::Impl::EV::],
234	[Event:: => AnyEvent::Impl::Event::],	450	[Event:: => AnyEvent::Impl::Event::],
235	[Glib:: => AnyEvent::Impl::Glib::],	451	[Glib:: => AnyEvent::Impl::Glib::],
236	[Tk:: => AnyEvent::Impl::Tk::],	452	[Tk:: => AnyEvent::Impl::Tk::],
237	[AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl::],	453	[AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl::],
		454	# everything below here will not be autoprobed as the pureperl backend should work everywhere
		455	[Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy
		456	[Qt:: => AnyEvent::Impl::Qt::], # requires special main program
		457	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza
238	);	458	);
239		459
240	our %method = map +($_ => 1), qw(io timer condvar broadcast wait DESTROY);	460	our %method = map +($_ => 1), qw(io timer signal child condvar broadcast wait one_event DESTROY);
241		461
242	sub AUTOLOAD {	462	sub detect() {
243	$AUTOLOAD =~ s/.*://;
244
245	$method{$AUTOLOAD}
246	or croak "$AUTOLOAD: not a valid method for AnyEvent objects";
247
248	unless ($MODEL) {	463	unless ($MODEL) {
		464	no strict 'refs';
		465
		466	if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) {
		467	my $model = "AnyEvent::Impl::$1";
		468	if (eval "require $model") {
		469	$MODEL = $model;
		470	warn "AnyEvent: loaded model '$model' (forced by \$PERL_ANYEVENT_MODEL), using it.\n" if $verbose > 1;
		471	} else {
		472	warn "AnyEvent: unable to load model '$model' (from \$PERL_ANYEVENT_MODEL):\n$@" if $verbose;
		473	}
		474	}
		475
249	# check for already loaded models	476	# check for already loaded models
		477	unless ($MODEL) {
250	for (@REGISTRY, @models) {	478	for (@REGISTRY, @models) {
251	my ($package, $model) = @$_;	479	my ($package, $model) = @$_;
252	if (${"$package\::VERSION"} > 0) {	480	if (${"$package\::VERSION"} > 0) {
253	if (eval "require $model") {	481	if (eval "require $model") {
254	$MODEL = $model;	482	$MODEL = $model;
255	warn "AnyEvent: found model '$model', using it.\n" if $verbose > 1;	483	warn "AnyEvent: autodetected model '$model', using it.\n" if $verbose > 1;
256	last;	484	last;
		485	}
257	}	486	}
258	}	487	}
		488
		489	unless ($MODEL) {
		490	# try to load a model
		491
		492	for (@REGISTRY, @models) {
		493	my ($package, $model) = @$_;
		494	if (eval "require $package"
		495	and ${"$package\::VERSION"} > 0
		496	and eval "require $model") {
		497	$MODEL = $model;
		498	warn "AnyEvent: autoprobed model '$model', using it.\n" if $verbose > 1;
		499	last;
		500	}
		501	}
		502
		503	$MODEL
		504	or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV (or Coro+EV), Event (or Coro+Event) or Glib.";
		505	}
259	}	506	}
260		507
261	unless ($MODEL) {	508	unshift @ISA, $MODEL;
262	# try to load a model	509	push @{"$MODEL\::ISA"}, "AnyEvent::Base";
263
264	for (@REGISTRY, @models) {
265	my ($package, $model) = @$_;
266	if (eval "require $model") {
267	$MODEL = $model;
268	warn "AnyEvent: autoprobed and loaded model '$model', using it.\n" if $verbose > 1;
269	last;
270	}
271	}
272
273	$MODEL
274	or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: Coro, Event, Glib or Tk.";
275	}
276	}	510	}
277		511
278	@ISA = $MODEL;	512	$MODEL
		513	}
		514
		515	sub AUTOLOAD {
		516	(my $func = $AUTOLOAD) =~ s/.*://;
		517
		518	$method{$func}
		519	or croak "$func: not a valid method for AnyEvent objects";
		520
		521	detect unless $MODEL;
279		522
280	my $class = shift;	523	my $class = shift;
281	$class->$AUTOLOAD (@_);	524	$class->$func (@_);
		525	}
		526
		527	package AnyEvent::Base;
		528
		529	# default implementation for ->condvar, ->wait, ->broadcast
		530
		531	sub condvar {
		532	bless \my $flag, "AnyEvent::Base::CondVar"
		533	}
		534
		535	sub AnyEvent::Base::CondVar::broadcast {
		536	${$_[0]}++;
		537	}
		538
		539	sub AnyEvent::Base::CondVar::wait {
		540	AnyEvent->one_event while !${$_[0]};
		541	}
		542
		543	# default implementation for ->signal
		544
		545	our %SIG_CB;
		546
		547	sub signal {
		548	my (undef, %arg) = @_;
		549
		550	my $signal = uc $arg{signal}
		551	or Carp::croak "required option 'signal' is missing";
		552
		553	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};
		554	$SIG{$signal} \|\|= sub {
		555	$_->() for values %{ $SIG_CB{$signal} \|\| {} };
		556	};
		557
		558	bless [$signal, $arg{cb}], "AnyEvent::Base::Signal"
		559	}
		560
		561	sub AnyEvent::Base::Signal::DESTROY {
		562	my ($signal, $cb) = @{$_[0]};
		563
		564	delete $SIG_CB{$signal}{$cb};
		565
		566	$SIG{$signal} = 'DEFAULT' unless keys %{ $SIG_CB{$signal} };
		567	}
		568
		569	# default implementation for ->child
		570
		571	our %PID_CB;
		572	our $CHLD_W;
		573	our $CHLD_DELAY_W;
		574	our $PID_IDLE;
		575	our $WNOHANG;
		576
		577	sub _child_wait {
		578	while (0 < (my $pid = waitpid -1, $WNOHANG)) {
		579	$_->($pid, $?) for (values %{ $PID_CB{$pid} \|\| {} }),
		580	(values %{ $PID_CB{0} \|\| {} });
		581	}
		582
		583	undef $PID_IDLE;
		584	}
		585
		586	sub _sigchld {
		587	# make sure we deliver these changes "synchronous" with the event loop.
		588	$CHLD_DELAY_W \|\|= AnyEvent->timer (after => 0, cb => sub {
		589	undef $CHLD_DELAY_W;
		590	&_child_wait;
		591	});
		592	}
		593
		594	sub child {
		595	my (undef, %arg) = @_;
		596
		597	defined (my $pid = $arg{pid} + 0)
		598	or Carp::croak "required option 'pid' is missing";
		599
		600	$PID_CB{$pid}{$arg{cb}} = $arg{cb};
		601
		602	unless ($WNOHANG) {
		603	$WNOHANG = eval { require POSIX; &POSIX::WNOHANG } \|\| 1;
		604	}
		605
		606	unless ($CHLD_W) {
		607	$CHLD_W = AnyEvent->signal (signal => 'CHLD', cb => \&_sigchld);
		608	# child could be a zombie already, so make at least one round
		609	&_sigchld;
		610	}
		611
		612	bless [$pid, $arg{cb}], "AnyEvent::Base::Child"
		613	}
		614
		615	sub AnyEvent::Base::Child::DESTROY {
		616	my ($pid, $cb) = @{$_[0]};
		617
		618	delete $PID_CB{$pid}{$cb};
		619	delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };
		620
		621	undef $CHLD_W unless keys %PID_CB;
282	}	622	}
283		623
284	=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE	624	=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE
		625
		626	This is an advanced topic that you do not normally need to use AnyEvent in
		627	a module. This section is only of use to event loop authors who want to
		628	provide AnyEvent compatibility.
285		629
286	If you need to support another event library which isn't directly	630	If you need to support another event library which isn't directly
287	supported by AnyEvent, you can supply your own interface to it by	631	supported by AnyEvent, you can supply your own interface to it by
288	pushing, before the first watcher gets created, the package name of	632	pushing, before the first watcher gets created, the package name of
289	the event module and the package name of the interface to use onto	633	the event module and the package name of the interface to use onto
290	C<@AnyEvent::REGISTRY>. You can do that before and even without loading	634	C<@AnyEvent::REGISTRY>. You can do that before and even without loading
291	AnyEvent.	635	AnyEvent, so it is reasonably cheap.
292		636
293	Example:	637	Example:
294		638
295	push @AnyEvent::REGISTRY, [urxvt => urxvt::anyevent::];	639	push @AnyEvent::REGISTRY, [urxvt => urxvt::anyevent::];
296		640
297	This tells AnyEvent to (literally) use the C<urxvt::anyevent::>	641	This tells AnyEvent to (literally) use the C<urxvt::anyevent::>
298	package/class when it finds the C<urxvt> package/module is loaded. When	642	package/class when it finds the C<urxvt> package/module is already loaded.
		643
299	AnyEvent is loaded and asked to find a suitable event model, it will	644	When AnyEvent is loaded and asked to find a suitable event model, it
300	first check for the presence of urxvt.	645	will first check for the presence of urxvt by trying to C<use> the
		646	C<urxvt::anyevent> module.
301		647
302	The class should prove implementations for all watcher types (see	648	The class should provide implementations for all watcher types. See
303	L<AnyEvent::Impl::Event> (source code), L<AnyEvent::Impl::Glib>	649	L<AnyEvent::Impl::EV> (source code), L<AnyEvent::Impl::Glib> (Source code)
304	(Source code) and so on for actual examples, use C<perldoc -m	650	and so on for actual examples. Use C<perldoc -m AnyEvent::Impl::Glib> to
305	AnyEvent::Impl::Glib> to see the sources).	651	see the sources.
306		652
		653	If you don't provide C<signal> and C<child> watchers than AnyEvent will
		654	provide suitable (hopefully) replacements.
		655
307	The above isn't fictitious, the I<rxvt-unicode> (a.k.a. urxvt)	656	The above example isn't fictitious, the I<rxvt-unicode> (a.k.a. urxvt)
308	uses the above line as-is. An interface isn't included in AnyEvent	657	terminal emulator uses the above line as-is. An interface isn't included
309	because it doesn't make sense outside the embedded interpreter inside	658	in AnyEvent because it doesn't make sense outside the embedded interpreter
310	I<rxvt-unicode>, and it is updated and maintained as part of the	659	inside I<rxvt-unicode>, and it is updated and maintained as part of the
311	I<rxvt-unicode> distribution.	660	I<rxvt-unicode> distribution.
312		661
313	I<rxvt-unicode> also cheats a bit by not providing blocking access to	662	I<rxvt-unicode> also cheats a bit by not providing blocking access to
314	condition variables: code blocking while waiting for a condition will	663	condition variables: code blocking while waiting for a condition will
315	C<die>. This still works with most modules/usages, and blocking calls must	664	C<die>. This still works with most modules/usages, and blocking calls must
316	not be in an interactive appliation, so it makes sense.	665	not be done in an interactive application, so it makes sense.
317		666
318	=head1 ENVIRONMENT VARIABLES	667	=head1 ENVIRONMENT VARIABLES
319		668
320	The following environment variables are used by this module:	669	The following environment variables are used by this module:
321		670
322	C<PERL_ANYEVENT_VERBOSE> when set to C<2> or higher, reports which event	671	=over 4
323	model gets used.
324		672
		673	=item C<PERL_ANYEVENT_VERBOSE>
		674
		675	By default, AnyEvent will be completely silent except in fatal
		676	conditions. You can set this environment variable to make AnyEvent more
		677	talkative.
		678
		679	When set to C<1> or higher, causes AnyEvent to warn about unexpected
		680	conditions, such as not being able to load the event model specified by
		681	C<PERL_ANYEVENT_MODEL>.
		682
		683	When set to C<2> or higher, cause AnyEvent to report to STDERR which event
		684	model it chooses.
		685
		686	=item C<PERL_ANYEVENT_MODEL>
		687
		688	This can be used to specify the event model to be used by AnyEvent, before
		689	autodetection and -probing kicks in. It must be a string consisting
		690	entirely of ASCII letters. The string C<AnyEvent::Impl::> gets prepended
		691	and the resulting module name is loaded and if the load was successful,
		692	used as event model. If it fails to load AnyEvent will proceed with
		693	autodetection and -probing.
		694
		695	This functionality might change in future versions.
		696
		697	For example, to force the pure perl model (L<AnyEvent::Impl::Perl>) you
		698	could start your program like this:
		699
		700	PERL_ANYEVENT_MODEL=Perl perl ...
		701
		702	=back
		703
325	=head1 EXAMPLE	704	=head1 EXAMPLE PROGRAM
326		705
327	The following program uses an io watcher to read data from stdin, a timer	706	The following program uses an IO watcher to read data from STDIN, a timer
328	to display a message once per second, and a condvar to exit the program	707	to display a message once per second, and a condition variable to quit the
329	when the user enters quit:	708	program when the user enters quit:
330		709
331	use AnyEvent;	710	use AnyEvent;
332		711
333	my $cv = AnyEvent->condvar;	712	my $cv = AnyEvent->condvar;
334		713
335	my $io_watcher = AnyEvent->io (fh => \*STDIN, poll => 'r', cb => sub {	714	my $io_watcher = AnyEvent->io (
		715	fh => \*STDIN,
		716	poll => 'r',
		717	cb => sub {
336	warn "io event <$_[0]>\n"; # will always output <r>	718	warn "io event <$_[0]>\n"; # will always output <r>
337	chomp (my $input = <STDIN>); # read a line	719	chomp (my $input = <STDIN>); # read a line
338	warn "read: $input\n"; # output what has been read	720	warn "read: $input\n"; # output what has been read
339	$cv->broadcast if $input =~ /^q/i; # quit program if /^q/i	721	$cv->broadcast if $input =~ /^q/i; # quit program if /^q/i
		722	},
340	});	723	);
341		724
342	my $time_watcher; # can only be used once	725	my $time_watcher; # can only be used once
343		726
344	sub new_timer {	727	sub new_timer {
345	$timer = AnyEvent->timer (after => 1, cb => sub {	728	$timer = AnyEvent->timer (after => 1, cb => sub {
…		…
427	$txn->{finished}->wait;	810	$txn->{finished}->wait;
428	return $txn->{result};	811	return $txn->{result};
429		812
430	The actual code goes further and collects all errors (C<die>s, exceptions)	813	The actual code goes further and collects all errors (C<die>s, exceptions)
431	that occured during request processing. The C<result> method detects	814	that occured during request processing. The C<result> method detects
432	wether an exception as thrown (it is stored inside the $txn object)	815	whether an exception as thrown (it is stored inside the $txn object)
433	and just throws the exception, which means connection errors and other	816	and just throws the exception, which means connection errors and other
434	problems get reported tot he code that tries to use the result, not in a	817	problems get reported tot he code that tries to use the result, not in a
435	random callback.	818	random callback.
436		819
437	All of this enables the following usage styles:	820	All of this enables the following usage styles:
438		821
439	1. Blocking:	822	1. Blocking:
440		823
441	my $data = $fcp->client_get ($url);	824	my $data = $fcp->client_get ($url);
442		825
443	2. Blocking, but parallelizing:	826	2. Blocking, but running in parallel:
444		827
445	my @datas = map $_->result,	828	my @datas = map $_->result,
446	map $fcp->txn_client_get ($_),	829	map $fcp->txn_client_get ($_),
447	@urls;	830	@urls;
448		831
449	Both blocking examples work without the module user having to know	832	Both blocking examples work without the module user having to know
450	anything about events.	833	anything about events.
451		834
452	3a. Event-based in a main program, using any support Event module:	835	3a. Event-based in a main program, using any supported event module:
453		836
454	use Event;	837	use EV;
455		838
456	$fcp->txn_client_get ($url)->cb (sub {	839	$fcp->txn_client_get ($url)->cb (sub {
457	my $txn = shift;	840	my $txn = shift;
458	my $data = $txn->result;	841	my $data = $txn->result;
459	...	842	...
460	});	843	});
461		844
462	Event::loop;	845	EV::loop;
463		846
464	3b. The module user could use AnyEvent, too:	847	3b. The module user could use AnyEvent, too:
465		848
466	use AnyEvent;	849	use AnyEvent;
467		850
…		…
472	$quit->broadcast;	855	$quit->broadcast;
473	});	856	});
474		857
475	$quit->wait;	858	$quit->wait;
476		859
		860	=head1 FORK
		861
		862	Most event libraries are not fork-safe. The ones who are usually are
		863	because they are so inefficient. Only L<EV> is fully fork-aware.
		864
		865	If you have to fork, you must either do so I<before> creating your first
		866	watcher OR you must not use AnyEvent at all in the child.
		867
		868	=head1 SECURITY CONSIDERATIONS
		869
		870	AnyEvent can be forced to load any event model via
		871	$ENV{PERL_ANYEVENT_MODEL}. While this cannot (to my knowledge) be used to
		872	execute arbitrary code or directly gain access, it can easily be used to
		873	make the program hang or malfunction in subtle ways, as AnyEvent watchers
		874	will not be active when the program uses a different event model than
		875	specified in the variable.
		876
		877	You can make AnyEvent completely ignore this variable by deleting it
		878	before the first watcher gets created, e.g. with a C<BEGIN> block:
		879
		880	BEGIN { delete $ENV{PERL_ANYEVENT_MODEL} }
		881
		882	use AnyEvent;
		883
477	=head1 SEE ALSO	884	=head1 SEE ALSO
478		885
479	Event modules: L<Coro::Event>, L<Coro>, L<Event>, L<Glib::Event>, L<Glib>.	886	Event modules: L<Coro::EV>, L<EV>, L<EV::Glib>, L<Glib::EV>,
		887	L<Coro::Event>, L<Event>, L<Glib::Event>, L<Glib>, L<Coro>, L<Tk>,
		888	L<Event::Lib>, L<Qt>, L<POE>.
480		889
		890	Implementations: L<AnyEvent::Impl::CoroEV>, L<AnyEvent::Impl::EV>,
481	Implementations: L<AnyEvent::Impl::Coro>, L<AnyEvent::Impl::Event>, L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>.	891	L<AnyEvent::Impl::CoroEvent>, L<AnyEvent::Impl::Event>, L<AnyEvent::Impl::Glib>,
		892	L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>, L<AnyEvent::Impl::EventLib>,
		893	L<AnyEvent::Impl::Qt>, L<AnyEvent::Impl::POE>.
482		894
483	Nontrivial usage example: L<Net::FCP>.	895	Nontrivial usage examples: L<Net::FCP>, L<Net::XMPP2>.
484		896
485	=head1	897	=head1 AUTHOR
		898
		899	Marc Lehmann <schmorp@schmorp.de>
		900	http://home.schmorp.de/
486		901
487	=cut	902	=cut
488		903
489	1	904	1
490		905

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Comparing AnyEvent/lib/AnyEvent.pm (file contents): Revision 1.17 by root, Fri Nov 24 14:40:13 2006 UTC vs. Revision 1.61 by root, Fri Apr 25 01:55:25 2008 UTC

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Comparing AnyEvent/lib/AnyEvent.pm (file contents):
Revision 1.17 by root, Fri Nov 24 14:40:13 2006 UTC vs.
Revision 1.61 by root, Fri Apr 25 01:55:25 2008 UTC