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

Comparing AnyEvent/lib/AnyEvent.pm (file contents):
Revision 1.16 by root, Sun Nov 5 01:08:16 2006 UTC vs.
Revision 1.60 by root, Fri Apr 25 01:05:26 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 - 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
35	loaded: L<Coro::Event>, L<Event>, L<Glib>, L<Tk>. The first one found is	84	the following modules is already loaded: L<Coro::EV>, L<Coro::Event>,
		85	L<EV>, L<Event>, L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>. The first one
36	used. If none is found, the module tries to load these modules in the	86	found is used. If none are found, the module tries to load these modules
37	order given. The first one that could be successfully loaded will be	87	(excluding Event::Lib and Qt) in the order given. The first one that can
38	used. If still none could be found, AnyEvent will fall back to a pure-perl	88	be successfully loaded will be used. If, after this, still none could be
39	event loop, which is also not very efficient.	89	found, AnyEvent will fall back to a pure-perl event loop, which is not
		90	very efficient, but should work everywhere.
40		91
41	Because AnyEvent first checks for modules that are already loaded, loading	92	Because AnyEvent first checks for modules that are already loaded, loading
42	an Event model explicitly before first using AnyEvent will likely make	93	an event model explicitly before first using AnyEvent will likely make
43	that model the default. For example:	94	that model the default. For example:
44		95
45	use Tk;	96	use Tk;
46	use AnyEvent;	97	use AnyEvent;
47		98
48	# .. AnyEvent will likely default to Tk	99	# .. AnyEvent will likely default to Tk
		100
		101	The I<likely> means that, if any module loads another event model and
		102	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...
49		104
50	The pure-perl implementation of AnyEvent is called	105	The pure-perl implementation of AnyEvent is called
51	C<AnyEvent::Impl::Perl>. Like other event modules you can load it	106	C<AnyEvent::Impl::Perl>. Like other event modules you can load it
52	explicitly.	107	explicitly.
53		108
…		…
56	AnyEvent has the central concept of a I<watcher>, which is an object that	111	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	112	stores relevant data for each kind of event you are waiting for, such as
58	the callback to call, the filehandle to watch, etc.	113	the callback to call, the filehandle to watch, etc.
59		114
60	These watchers are normal Perl objects with normal Perl lifetime. After	115	These watchers are normal Perl objects with normal Perl lifetime. After
61	creating a watcher it will immediately "watch" for events and invoke	116	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
		118	is in control).
		119
62	the callback. To disable the watcher you have to destroy it (e.g. by	120	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	121	variable you store it in to C<undef> or otherwise deleting all references
64	references to it).	122	to it).
65		123
66	All watchers are created by calling a method on the C<AnyEvent> class.	124	All watchers are created by calling a method on the C<AnyEvent> class.
67		125
		126	Many watchers either are used with "recursion" (repeating timers for
		127	example), or need to refer to their watcher object in other ways.
		128
		129	An any way to achieve that is this pattern:
		130
		131	my $w; $w = AnyEvent->type (arg => value ..., cb => sub {
		132	# you can use $w here, for example to undef it
		133	undef $w;
		134	});
		135
		136	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
		138	declared.
		139
68	=head2 IO WATCHERS	140	=head2 IO WATCHERS
69		141
70	You can create I/O watcher by calling the C<< AnyEvent->io >> method with	142	You can create an I/O watcher by calling the C<< AnyEvent->io >> method
71	the following mandatory arguments:	143	with the following mandatory key-value pairs as arguments:
72		144
73	C<fh> the Perl I<filehandle> (not filedescriptor) to watch for	145	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	146	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	147	creates a watcher waiting for "r"eadable or "w"ritable events,
76	to invoke everytime the filehandle becomes ready.	148	respectively. C<cb> is the callback to invoke each time the file handle
		149	becomes ready.
77		150
78	Only one io watcher per C<fh> and C<poll> combination is allowed (i.e. on	151	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	152	copy of it alive/open.
80	Tk - if you are sure you are not using Tk this limitation is gone).
81		153
82	Filehandles will be kept alive, so as long as the watcher exists, the	154	It is not allowed to close a file handle as long as any watcher is active
83	filehandle exists, too.	155	on the underlying file descriptor.
		156
		157	Some event loops issue spurious readyness notifications, so you should
		158	always use non-blocking calls when reading/writing from/to your file
		159	handles.
84		160
85	Example:	161	Example:
86		162
87	# wait for readability of STDIN, then read a line and disable the watcher	163	# 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 {	164	my $w; $w = AnyEvent->io (fh => \*STDIN, poll => 'r', cb => sub {
89	chomp (my $input = <STDIN>);	165	chomp (my $input = <STDIN>);
90	warn "read: $input\n";	166	warn "read: $input\n";
91	undef $w;	167	undef $w;
92	});	168	});
93		169
94	=head2 TIMER WATCHERS	170	=head2 TIME WATCHERS
95		171
96	You can create a timer watcher by calling the C<< AnyEvent->timer >>	172	You can create a time watcher by calling the C<< AnyEvent->timer >>
97	method with the following mandatory arguments:	173	method with the following mandatory arguments:
98		174
99	C<after> after how many seconds (fractions are supported) should the timer	175	C<after> specifies after how many seconds (fractional values are
100	activate. C<cb> the callback to invoke.	176	supported) should the timer activate. C<cb> the callback to invoke in that
		177	case.
101		178
102	The timer callback will be invoked at most once: if you want a repeating	179	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	180	timer you have to create a new watcher (this is a limitation by both Tk
104	and Glib).	181	and Glib).
105		182
…		…
109	my $w = AnyEvent->timer (after => 7.7, cb => sub {	186	my $w = AnyEvent->timer (after => 7.7, cb => sub {
110	warn "timeout\n";	187	warn "timeout\n";
111	});	188	});
112		189
113	# to cancel the timer:	190	# to cancel the timer:
114	undef $w	191	undef $w;
115		192
		193	Example 2:
		194
		195	# fire an event after 0.5 seconds, then roughly every second
		196	my $w;
		197
		198	my $cb = sub {
		199	# cancel the old timer while creating a new one
		200	$w = AnyEvent->timer (after => 1, cb => $cb);
		201	};
		202
		203	# start the "loop" by creating the first watcher
		204	$w = AnyEvent->timer (after => 0.5, cb => $cb);
		205
		206	=head3 TIMING ISSUES
		207
		208	There are two ways to handle timers: based on real time (relative, "fire
		209	in 10 seconds") and based on wallclock time (absolute, "fire at 12
		210	o'clock").
		211
		212	While most event loops expect timers to specified in a relative way, they
		213	use absolute time internally. This makes a difference when your clock
		214	"jumps", for example, when ntp decides to set your clock backwards from
		215	the wrong date of 2014-01-01 to 2008-01-01, a watcher that is supposed to
		216	fire "after" a second might actually take six years to finally fire.
		217
		218	AnyEvent cannot compensate for this. The only event loop that is conscious
		219	about these issues is L<EV>, which offers both relative (ev_timer, based
		220	on true relative time) and absolute (ev_periodic, based on wallclock time)
		221	timers.
		222
		223	AnyEvent always prefers relative timers, if available, matching the
		224	AnyEvent API.
		225
		226	=head2 SIGNAL WATCHERS
		227
		228	You can watch for signals using a signal watcher, C<signal> is the signal
		229	I<name> without any C<SIG> prefix, C<cb> is the Perl callback to
		230	be invoked whenever a signal occurs.
		231
		232	Multiple signal occurances can be clumped together into one callback
		233	invocation, and callback invocation will be synchronous. synchronous means
		234	that it might take a while until the signal gets handled by the process,
		235	but it is guarenteed not to interrupt any other callbacks.
		236
		237	The main advantage of using these watchers is that you can share a signal
		238	between multiple watchers.
		239
		240	This watcher might use C<%SIG>, so programs overwriting those signals
		241	directly will likely not work correctly.
		242
		243	Example: exit on SIGINT
		244
		245	my $w = AnyEvent->signal (signal => "INT", cb => sub { exit 1 });
		246
		247	=head2 CHILD PROCESS WATCHERS
		248
		249	You can also watch on a child process exit and catch its exit status.
		250
		251	The child process is specified by the C<pid> argument (if set to C<0>, it
		252	watches for any child process exit). The watcher will trigger as often
		253	as status change for the child are received. This works by installing a
		254	signal handler for C<SIGCHLD>. The callback will be called with the pid
		255	and exit status (as returned by waitpid).
		256
		257	Example: wait for pid 1333
		258
		259	my $w = AnyEvent->child (
		260	pid => 1333,
		261	cb => sub {
		262	my ($pid, $status) = @_;
		263	warn "pid $pid exited with status $status";
		264	},
		265	);
		266
116	=head2 CONDITION WATCHERS	267	=head2 CONDITION VARIABLES
117		268
118	Condition watchers can be created by calling the C<< AnyEvent->condvar >>	269	Condition variables can be created by calling the C<< AnyEvent->condvar >>
119	method without any arguments.	270	method without any arguments.
120		271
121	A condition watcher watches for a condition - precisely that the C<<	272	A condition variable waits for a condition - precisely that the C<<
122	->broadcast >> method has been called.	273	->broadcast >> method has been called.
123		274
124	The watcher has only two methods:	275	They are very useful to signal that a condition has been fulfilled, for
		276	example, if you write a module that does asynchronous http requests,
		277	then a condition variable would be the ideal candidate to signal the
		278	availability of results.
		279
		280	You can also use condition variables to block your main program until
		281	an event occurs - for example, you could C<< ->wait >> in your main
		282	program until the user clicks the Quit button in your app, which would C<<
		283	->broadcast >> the "quit" event.
		284
		285	Note that condition variables recurse into the event loop - if you have
		286	two pirces of code that call C<< ->wait >> in a round-robbin fashion, you
		287	lose. Therefore, condition variables are good to export to your caller, but
		288	you should avoid making a blocking wait yourself, at least in callbacks,
		289	as this asks for trouble.
		290
		291	This object has two methods:
125		292
126	=over 4	293	=over 4
127		294
128	=item $cv->wait	295	=item $cv->wait
129		296
130	Wait (blocking if necessary) until the C<< ->broadcast >> method has been	297	Wait (blocking if necessary) until the C<< ->broadcast >> method has been
131	called on c<$cv>, while servicing other watchers normally.	298	called on c<$cv>, while servicing other watchers normally.
132		299
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	300	You can only wait once on a condition - additional calls will return
141	immediately.	301	immediately.
142		302
		303	Not all event models support a blocking wait - some die in that case
		304	(programs might want to do that to stay interactive), so I<if you are
		305	using this from a module, never require a blocking wait>, but let the
		306	caller decide whether the call will block or not (for example, by coupling
		307	condition variables with some kind of request results and supporting
		308	callbacks so the caller knows that getting the result will not block,
		309	while still suppporting blocking waits if the caller so desires).
		310
		311	Another reason I<never> to C<< ->wait >> in a module is that you cannot
		312	sensibly have two C<< ->wait >>'s in parallel, as that would require
		313	multiple interpreters or coroutines/threads, none of which C<AnyEvent>
		314	can supply (the coroutine-aware backends L<AnyEvent::Impl::CoroEV> and
		315	L<AnyEvent::Impl::CoroEvent> explicitly support concurrent C<< ->wait >>'s
		316	from different coroutines, however).
		317
143	=item $cv->broadcast	318	=item $cv->broadcast
144		319
145	Flag the condition as ready - a running C<< ->wait >> and all further	320	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	321	calls to C<wait> will (eventually) return after this method has been
147	is waiting the broadcast will be remembered..	322	called. If nobody is waiting the broadcast will be remembered..
		323
		324	=back
148		325
149	Example:	326	Example:
150		327
151	# wait till the result is ready	328	# wait till the result is ready
152	my $result_ready = AnyEvent->condvar;	329	my $result_ready = AnyEvent->condvar;
153		330
154	# do something such as adding a timer	331	# do something such as adding a timer
155	# or socket watcher the calls $result_ready->broadcast	332	# or socket watcher the calls $result_ready->broadcast
156	# when the "result" is ready.	333	# when the "result" is ready.
		334	# in this case, we simply use a timer:
		335	my $w = AnyEvent->timer (
		336	after => 1,
		337	cb => sub { $result_ready->broadcast },
		338	);
157		339
		340	# this "blocks" (while handling events) till the watcher
		341	# calls broadcast
158	$result_ready->wait;	342	$result_ready->wait;
159		343
160	=back	344	=head1 GLOBAL VARIABLES AND FUNCTIONS
161
162	=head1 GLOBALS
163		345
164	=over 4	346	=over 4
165		347
166	=item $AnyEvent::MODEL	348	=item $AnyEvent::MODEL
167		349
…		…
171	C<AnyEvent::Impl:xxx> modules, but can be any other class in the case	353	C<AnyEvent::Impl:xxx> modules, but can be any other class in the case
172	AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode>).	354	AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode>).
173		355
174	The known classes so far are:	356	The known classes so far are:
175		357
176	AnyEvent::Impl::Coro based on Coro::Event, best choise.	358	AnyEvent::Impl::CoroEV based on Coro::EV, best choice.
		359	AnyEvent::Impl::CoroEvent based on Coro::Event, second best choice.
		360	AnyEvent::Impl::EV based on EV (an interface to libev, best choice).
177	AnyEvent::Impl::Event based on Event, also best choice :)	361	AnyEvent::Impl::Event based on Event, second best choice.
178	AnyEvent::Impl::Glib based on Glib, second-best choice.	362	AnyEvent::Impl::Glib based on Glib, third-best choice.
179	AnyEvent::Impl::Tk based on Tk, very bad choice.	363	AnyEvent::Impl::Tk based on Tk, very bad choice.
180	AnyEvent::Impl::Perl pure-perl implementation, inefficient.	364	AnyEvent::Impl::Perl pure-perl implementation, inefficient but portable.
		365	AnyEvent::Impl::Qt based on Qt, cannot be autoprobed (see its docs).
		366	AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse.
		367
		368	=item AnyEvent::detect
		369
		370	Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model
		371	if necessary. You should only call this function right before you would
		372	have created an AnyEvent watcher anyway, that is, as late as possible at
		373	runtime.
181		374
182	=back	375	=back
183		376
184	=head1 WHAT TO DO IN A MODULE	377	=head1 WHAT TO DO IN A MODULE
185		378
186	As a module author, you should "use AnyEvent" and call AnyEvent methods	379	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.	380	freely, but you should not load a specific event module or rely on it.
188		381
189	Be careful when you create watchers in the module body - Anyevent will	382	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	383	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	384	by calling AnyEvent in your module body you force the user of your module
192	to load the event module first.	385	to load the event module first.
193		386
		387	Never call C<< ->wait >> on a condition variable unless you I<know> that
		388	the C<< ->broadcast >> method has been called on it already. This is
		389	because it will stall the whole program, and the whole point of using
		390	events is to stay interactive.
		391
		392	It is fine, however, to call C<< ->wait >> when the user of your module
		393	requests it (i.e. if you create a http request object ad have a method
		394	called C<results> that returns the results, it should call C<< ->wait >>
		395	freely, as the user of your module knows what she is doing. always).
		396
194	=head1 WHAT TO DO IN THE MAIN PROGRAM	397	=head1 WHAT TO DO IN THE MAIN PROGRAM
195		398
196	There will always be a single main program - the only place that should	399	There will always be a single main program - the only place that should
197	dictate which event model to use.	400	dictate which event model to use.
198		401
199	If it doesn't care, it can just "use AnyEvent" and use it itself, or not	402	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.	403	do anything special (it does not need to be event-based) and let AnyEvent
		404	decide which implementation to chose if some module relies on it.
201		405
202	If the main program relies on a specific event model (for example, in Gtk2	406	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	407	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	408	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	409	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	410	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	411	decide on the event model to use as soon as it creates watchers, and it
208	correct one yourself.	412	might chose the wrong one unless you load the correct one yourself.
209		413
210	You can chose to use a rather inefficient pure-perl implementation by	414	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	415	loading the C<AnyEvent::Impl::Perl> module, which gives you similar
212	generally better.	416	behaviour everywhere, but letting AnyEvent chose is generally better.
213		417
214	=cut	418	=cut
215		419
216	package AnyEvent;	420	package AnyEvent;
217		421
218	no warnings;	422	no warnings;
219	use strict 'vars';	423	use strict;
		424
220	use Carp;	425	use Carp;
221		426
222	our $VERSION = '2.0';	427	our $VERSION = '3.2';
223	our $MODEL;	428	our $MODEL;
224		429
225	our $AUTOLOAD;	430	our $AUTOLOAD;
226	our @ISA;	431	our @ISA;
227		432
228	our $verbose = $ENV{PERL_ANYEVENT_VERBOSE}*1;	433	our $verbose = $ENV{PERL_ANYEVENT_VERBOSE}*1;
229		434
230	our @REGISTRY;	435	our @REGISTRY;
231		436
232	my @models = (	437	my @models = (
		438	[Coro::EV:: => AnyEvent::Impl::CoroEV::],
233	[Coro::Event:: => AnyEvent::Impl::Coro::],	439	[Coro::Event:: => AnyEvent::Impl::CoroEvent::],
		440	[EV:: => AnyEvent::Impl::EV::],
234	[Event:: => AnyEvent::Impl::Event::],	441	[Event:: => AnyEvent::Impl::Event::],
235	[Glib:: => AnyEvent::Impl::Glib::],	442	[Glib:: => AnyEvent::Impl::Glib::],
236	[Tk:: => AnyEvent::Impl::Tk::],	443	[Tk:: => AnyEvent::Impl::Tk::],
237	[AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl::],	444	[AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl::],
238	);	445	);
		446	my @models_detect = (
		447	[Qt:: => AnyEvent::Impl::Qt::], # requires special main program
		448	[Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy
		449	);
239		450
240	our %method = map +($_ => 1), qw(io timer condvar broadcast wait DESTROY);	451	our %method = map +($_ => 1), qw(io timer signal child condvar broadcast wait one_event DESTROY);
241		452
242	sub AUTOLOAD {	453	sub detect() {
243	$AUTOLOAD =~ s/.*://;
244
245	$method{$AUTOLOAD}
246	or croak "$AUTOLOAD: not a valid method for AnyEvent objects";
247
248	unless ($MODEL) {	454	unless ($MODEL) {
		455	no strict 'refs';
		456
		457	if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) {
		458	my $model = "AnyEvent::Impl::$1";
		459	if (eval "require $model") {
		460	$MODEL = $model;
		461	warn "AnyEvent: loaded model '$model' (forced by \$PERL_ANYEVENT_MODEL), using it.\n" if $verbose > 1;
		462	} else {
		463	warn "AnyEvent: unable to load model '$model' (from \$PERL_ANYEVENT_MODEL):\n$@" if $verbose;
		464	}
		465	}
		466
249	# check for already loaded models	467	# check for already loaded models
		468	unless ($MODEL) {
250	for (@REGISTRY, @models) {	469	for (@REGISTRY, @models, @models_detect) {
251	my ($package, $model) = @$_;	470	my ($package, $model) = @$_;
252	if (${"$package\::VERSION"} > 0) {	471	if (${"$package\::VERSION"} > 0) {
253	if (eval "require $model") {	472	if (eval "require $model") {
254	$MODEL = $model;	473	$MODEL = $model;
255	warn "AnyEvent: found model '$model', using it.\n" if $verbose > 1;	474	warn "AnyEvent: autodetected model '$model', using it.\n" if $verbose > 1;
256	last;	475	last;
		476	}
257	}	477	}
258	}	478	}
		479
		480	unless ($MODEL) {
		481	# try to load a model
		482
		483	for (@REGISTRY, @models) {
		484	my ($package, $model) = @$_;
		485	if (eval "require $package"
		486	and ${"$package\::VERSION"} > 0
		487	and eval "require $model") {
		488	$MODEL = $model;
		489	warn "AnyEvent: autoprobed model '$model', using it.\n" if $verbose > 1;
		490	last;
		491	}
		492	}
		493
		494	$MODEL
		495	or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV (or Coro+EV), Event (or Coro+Event) or Glib.";
		496	}
259	}	497	}
260		498
261	unless ($MODEL) {	499	unshift @ISA, $MODEL;
262	# try to load a model	500	push @{"$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	}	501	}
277		502
278	@ISA = $MODEL;	503	$MODEL
		504	}
		505
		506	sub AUTOLOAD {
		507	(my $func = $AUTOLOAD) =~ s/.*://;
		508
		509	$method{$func}
		510	or croak "$func: not a valid method for AnyEvent objects";
		511
		512	detect unless $MODEL;
279		513
280	my $class = shift;	514	my $class = shift;
281	$class->$AUTOLOAD (@_);	515	$class->$func (@_);
		516	}
		517
		518	package AnyEvent::Base;
		519
		520	# default implementation for ->condvar, ->wait, ->broadcast
		521
		522	sub condvar {
		523	bless \my $flag, "AnyEvent::Base::CondVar"
		524	}
		525
		526	sub AnyEvent::Base::CondVar::broadcast {
		527	${$_[0]}++;
		528	}
		529
		530	sub AnyEvent::Base::CondVar::wait {
		531	AnyEvent->one_event while !${$_[0]};
		532	}
		533
		534	# default implementation for ->signal
		535
		536	our %SIG_CB;
		537
		538	sub signal {
		539	my (undef, %arg) = @_;
		540
		541	my $signal = uc $arg{signal}
		542	or Carp::croak "required option 'signal' is missing";
		543
		544	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};
		545	$SIG{$signal} \|\|= sub {
		546	$_->() for values %{ $SIG_CB{$signal} \|\| {} };
		547	};
		548
		549	bless [$signal, $arg{cb}], "AnyEvent::Base::Signal"
		550	}
		551
		552	sub AnyEvent::Base::Signal::DESTROY {
		553	my ($signal, $cb) = @{$_[0]};
		554
		555	delete $SIG_CB{$signal}{$cb};
		556
		557	$SIG{$signal} = 'DEFAULT' unless keys %{ $SIG_CB{$signal} };
		558	}
		559
		560	# default implementation for ->child
		561
		562	our %PID_CB;
		563	our $CHLD_W;
		564	our $CHLD_DELAY_W;
		565	our $PID_IDLE;
		566	our $WNOHANG;
		567
		568	sub _child_wait {
		569	while (0 < (my $pid = waitpid -1, $WNOHANG)) {
		570	$_->($pid, $?) for (values %{ $PID_CB{$pid} \|\| {} }),
		571	(values %{ $PID_CB{0} \|\| {} });
		572	}
		573
		574	undef $PID_IDLE;
		575	}
		576
		577	sub _sigchld {
		578	# make sure we deliver these changes "synchronous" with the event loop.
		579	$CHLD_DELAY_W \|\|= AnyEvent->timer (after => 0, cb => sub {
		580	undef $CHLD_DELAY_W;
		581	&_child_wait;
		582	});
		583	}
		584
		585	sub child {
		586	my (undef, %arg) = @_;
		587
		588	defined (my $pid = $arg{pid} + 0)
		589	or Carp::croak "required option 'pid' is missing";
		590
		591	$PID_CB{$pid}{$arg{cb}} = $arg{cb};
		592
		593	unless ($WNOHANG) {
		594	$WNOHANG = eval { require POSIX; &POSIX::WNOHANG } \|\| 1;
		595	}
		596
		597	unless ($CHLD_W) {
		598	$CHLD_W = AnyEvent->signal (signal => 'CHLD', cb => \&_sigchld);
		599	# child could be a zombie already, so make at least one round
		600	&_sigchld;
		601	}
		602
		603	bless [$pid, $arg{cb}], "AnyEvent::Base::Child"
		604	}
		605
		606	sub AnyEvent::Base::Child::DESTROY {
		607	my ($pid, $cb) = @{$_[0]};
		608
		609	delete $PID_CB{$pid}{$cb};
		610	delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };
		611
		612	undef $CHLD_W unless keys %PID_CB;
282	}	613	}
283		614
284	=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE	615	=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE
		616
		617	This is an advanced topic that you do not normally need to use AnyEvent in
		618	a module. This section is only of use to event loop authors who want to
		619	provide AnyEvent compatibility.
285		620
286	If you need to support another event library which isn't directly	621	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	622	supported by AnyEvent, you can supply your own interface to it by
288	pushing, before the first watcher gets created, the package name of	623	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	624	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	625	C<@AnyEvent::REGISTRY>. You can do that before and even without loading
291	AnyEvent.	626	AnyEvent, so it is reasonably cheap.
292		627
293	Example:	628	Example:
294		629
295	push @AnyEvent::REGISTRY, [urxvt => urxvt::anyevent::];	630	push @AnyEvent::REGISTRY, [urxvt => urxvt::anyevent::];
296		631
297	This tells AnyEvent to (literally) use the C<urxvt::anyevent::>	632	This tells AnyEvent to (literally) use the C<urxvt::anyevent::>
298	package/class when it finds the C<urxvt> package/module is loaded. When	633	package/class when it finds the C<urxvt> package/module is already loaded.
		634
299	AnyEvent is loaded and asked to find a suitable event model, it will	635	When AnyEvent is loaded and asked to find a suitable event model, it
300	first check for the presence of urxvt.	636	will first check for the presence of urxvt by trying to C<use> the
		637	C<urxvt::anyevent> module.
301		638
302	The class should prove implementations for all watcher types (see	639	The class should provide implementations for all watcher types. See
303	L<AnyEvent::Impl::Event> (source code), L<AnyEvent::Impl::Glib>	640	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	641	and so on for actual examples. Use C<perldoc -m AnyEvent::Impl::Glib> to
305	AnyEvent::Impl::Glib> to see the sources).	642	see the sources.
306		643
		644	If you don't provide C<signal> and C<child> watchers than AnyEvent will
		645	provide suitable (hopefully) replacements.
		646
307	The above isn't fictitious, the I<rxvt-unicode> (a.k.a. urxvt)	647	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	648	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	649	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	650	inside I<rxvt-unicode>, and it is updated and maintained as part of the
311	I<rxvt-unicode> distribution.	651	I<rxvt-unicode> distribution.
312		652
313	I<rxvt-unicode> also cheats a bit by not providing blocking access to	653	I<rxvt-unicode> also cheats a bit by not providing blocking access to
314	condition variables: code blocking while waiting for a condition will	654	condition variables: code blocking while waiting for a condition will
315	C<die>. This still works with most modules/usages, and blocking calls must	655	C<die>. This still works with most modules/usages, and blocking calls must
316	not be in an interactive appliation, so it makes sense.	656	not be done in an interactive application, so it makes sense.
317		657
318	=head1 ENVIRONMENT VARIABLES	658	=head1 ENVIRONMENT VARIABLES
319		659
320	The following environment variables are used by this module:	660	The following environment variables are used by this module:
321		661
322	C<PERL_ANYEVENT_VERBOSE> when set to C<2> or higher, reports which event	662	=over 4
323	model gets used.
324		663
		664	=item C<PERL_ANYEVENT_VERBOSE>
		665
		666	By default, AnyEvent will be completely silent except in fatal
		667	conditions. You can set this environment variable to make AnyEvent more
		668	talkative.
		669
		670	When set to C<1> or higher, causes AnyEvent to warn about unexpected
		671	conditions, such as not being able to load the event model specified by
		672	C<PERL_ANYEVENT_MODEL>.
		673
		674	When set to C<2> or higher, cause AnyEvent to report to STDERR which event
		675	model it chooses.
		676
		677	=item C<PERL_ANYEVENT_MODEL>
		678
		679	This can be used to specify the event model to be used by AnyEvent, before
		680	autodetection and -probing kicks in. It must be a string consisting
		681	entirely of ASCII letters. The string C<AnyEvent::Impl::> gets prepended
		682	and the resulting module name is loaded and if the load was successful,
		683	used as event model. If it fails to load AnyEvent will proceed with
		684	autodetection and -probing.
		685
		686	This functionality might change in future versions.
		687
		688	For example, to force the pure perl model (L<AnyEvent::Impl::Perl>) you
		689	could start your program like this:
		690
		691	PERL_ANYEVENT_MODEL=Perl perl ...
		692
		693	=back
		694
325	=head1 EXAMPLE	695	=head1 EXAMPLE PROGRAM
326		696
327	The following program uses an io watcher to read data from stdin, a timer	697	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	698	to display a message once per second, and a condition variable to quit the
329	when the user enters quit:	699	program when the user enters quit:
330		700
331	use AnyEvent;	701	use AnyEvent;
332		702
333	my $cv = AnyEvent->condvar;	703	my $cv = AnyEvent->condvar;
334		704
335	my $io_watcher = AnyEvent->io (fh => \*STDIN, poll => 'r', cb => sub {	705	my $io_watcher = AnyEvent->io (
		706	fh => \*STDIN,
		707	poll => 'r',
		708	cb => sub {
336	warn "io event <$_[0]>\n"; # will always output <r>	709	warn "io event <$_[0]>\n"; # will always output <r>
337	chomp (my $input = <STDIN>); # read a line	710	chomp (my $input = <STDIN>); # read a line
338	warn "read: $input\n"; # output what has been read	711	warn "read: $input\n"; # output what has been read
339	$cv->broadcast if $input =~ /^q/i; # quit program if /^q/i	712	$cv->broadcast if $input =~ /^q/i; # quit program if /^q/i
		713	},
340	});	714	);
341		715
342	my $time_watcher; # can only be used once	716	my $time_watcher; # can only be used once
343		717
344	sub new_timer {	718	sub new_timer {
345	$timer = AnyEvent->timer (after => 1, cb => sub {	719	$timer = AnyEvent->timer (after => 1, cb => sub {
…		…
427	$txn->{finished}->wait;	801	$txn->{finished}->wait;
428	return $txn->{result};	802	return $txn->{result};
429		803
430	The actual code goes further and collects all errors (C<die>s, exceptions)	804	The actual code goes further and collects all errors (C<die>s, exceptions)
431	that occured during request processing. The C<result> method detects	805	that occured during request processing. The C<result> method detects
432	wether an exception as thrown (it is stored inside the $txn object)	806	whether an exception as thrown (it is stored inside the $txn object)
433	and just throws the exception, which means connection errors and other	807	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	808	problems get reported tot he code that tries to use the result, not in a
435	random callback.	809	random callback.
436		810
437	All of this enables the following usage styles:	811	All of this enables the following usage styles:
438		812
439	1. Blocking:	813	1. Blocking:
440		814
441	my $data = $fcp->client_get ($url);	815	my $data = $fcp->client_get ($url);
442		816
443	2. Blocking, but parallelizing:	817	2. Blocking, but running in parallel:
444		818
445	my @datas = map $_->result,	819	my @datas = map $_->result,
446	map $fcp->txn_client_get ($_),	820	map $fcp->txn_client_get ($_),
447	@urls;	821	@urls;
448		822
449	Both blocking examples work without the module user having to know	823	Both blocking examples work without the module user having to know
450	anything about events.	824	anything about events.
451		825
452	3a. Event-based in a main program, using any support Event module:	826	3a. Event-based in a main program, using any supported event module:
453		827
454	use Event;	828	use EV;
455		829
456	$fcp->txn_client_get ($url)->cb (sub {	830	$fcp->txn_client_get ($url)->cb (sub {
457	my $txn = shift;	831	my $txn = shift;
458	my $data = $txn->result;	832	my $data = $txn->result;
459	...	833	...
460	});	834	});
461		835
462	Event::loop;	836	EV::loop;
463		837
464	3b. The module user could use AnyEvent, too:	838	3b. The module user could use AnyEvent, too:
465		839
466	use AnyEvent;	840	use AnyEvent;
467		841
…		…
472	$quit->broadcast;	846	$quit->broadcast;
473	});	847	});
474		848
475	$quit->wait;	849	$quit->wait;
476		850
		851	=head1 FORK
		852
		853	Most event libraries are not fork-safe. The ones who are usually are
		854	because they are so inefficient. Only L<EV> is fully fork-aware.
		855
		856	If you have to fork, you must either do so I<before> creating your first
		857	watcher OR you must not use AnyEvent at all in the child.
		858
		859	=head1 SECURITY CONSIDERATIONS
		860
		861	AnyEvent can be forced to load any event model via
		862	$ENV{PERL_ANYEVENT_MODEL}. While this cannot (to my knowledge) be used to
		863	execute arbitrary code or directly gain access, it can easily be used to
		864	make the program hang or malfunction in subtle ways, as AnyEvent watchers
		865	will not be active when the program uses a different event model than
		866	specified in the variable.
		867
		868	You can make AnyEvent completely ignore this variable by deleting it
		869	before the first watcher gets created, e.g. with a C<BEGIN> block:
		870
		871	BEGIN { delete $ENV{PERL_ANYEVENT_MODEL} }
		872
		873	use AnyEvent;
		874
477	=head1 SEE ALSO	875	=head1 SEE ALSO
478		876
479	Event modules: L<Coro::Event>, L<Coro>, L<Event>, L<Glib::Event>, L<Glib>.	877	Event modules: L<Coro::EV>, L<EV>, L<EV::Glib>, L<Glib::EV>,
		878	L<Coro::Event>, L<Event>, L<Glib::Event>, L<Glib>, L<Coro>, L<Tk>,
		879	L<Event::Lib>, L<Qt>.
480		880
		881	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>.	882	L<AnyEvent::Impl::CoroEvent>, L<AnyEvent::Impl::Event>, L<AnyEvent::Impl::Glib>,
		883	L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>, L<AnyEvent::Impl::EventLib>,
		884	L<AnyEvent::Impl::Qt>.
482		885
483	Nontrivial usage example: L<Net::FCP>.	886	Nontrivial usage examples: L<Net::FCP>, L<Net::XMPP2>.
484		887
485	=head1	888	=head1 AUTHOR
		889
		890	Marc Lehmann <schmorp@schmorp.de>
		891	http://home.schmorp.de/
486		892
487	=cut	893	=cut
488		894
489	1	895	1
490		896

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Comparing AnyEvent/lib/AnyEvent.pm (file contents): Revision 1.16 by root, Sun Nov 5 01:08:16 2006 UTC vs. Revision 1.60 by root, Fri Apr 25 01:05:26 2008 UTC

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Comparing AnyEvent/lib/AnyEvent.pm (file contents):
Revision 1.16 by root, Sun Nov 5 01:08:16 2006 UTC vs.
Revision 1.60 by root, Fri Apr 25 01:05:26 2008 UTC