[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 1.55 by root, Wed Apr 23 11:25:42 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 - 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>. The first one found is used. If none are found,
37	order given. The first one that could be successfully loaded will be	86	the module tries to load these modules in the stated order. The first one
38	used. If still none could be found, AnyEvent will fall back to a pure-perl	87	that can be successfully loaded will be used. If, after this, still none
39	event loop, which is also not very efficient.	88	could be found, AnyEvent will fall back to a pure-perl event loop, which
		89	is not very efficient, but should work everywhere.
40		90
41	Because AnyEvent first checks for modules that are already loaded, loading	91	Because AnyEvent first checks for modules that are already loaded, loading
42	an Event model explicitly before first using AnyEvent will likely make	92	an event model explicitly before first using AnyEvent will likely make
43	that model the default. For example:	93	that model the default. For example:
44		94
45	use Tk;	95	use Tk;
46	use AnyEvent;	96	use AnyEvent;
47		97
48	# .. AnyEvent will likely default to Tk	98	# .. AnyEvent will likely default to Tk
		99
		100	The I<likely> means that, if any module loads another event model and
		101	starts using it, all bets are off. Maybe you should tell their authors to
		102	use AnyEvent so their modules work together with others seamlessly...
49		103
50	The pure-perl implementation of AnyEvent is called	104	The pure-perl implementation of AnyEvent is called
51	C<AnyEvent::Impl::Perl>. Like other event modules you can load it	105	C<AnyEvent::Impl::Perl>. Like other event modules you can load it
52	explicitly.	106	explicitly.
53		107
…		…
56	AnyEvent has the central concept of a I<watcher>, which is an object that	110	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	111	stores relevant data for each kind of event you are waiting for, such as
58	the callback to call, the filehandle to watch, etc.	112	the callback to call, the filehandle to watch, etc.
59		113
60	These watchers are normal Perl objects with normal Perl lifetime. After	114	These watchers are normal Perl objects with normal Perl lifetime. After
61	creating a watcher it will immediately "watch" for events and invoke	115	creating a watcher it will immediately "watch" for events and invoke the
		116	callback when the event occurs (of course, only when the event model
		117	is in control).
		118
62	the callback. To disable the watcher you have to destroy it (e.g. by	119	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	120	variable you store it in to C<undef> or otherwise deleting all references
64	references to it).	121	to it).
65		122
66	All watchers are created by calling a method on the C<AnyEvent> class.	123	All watchers are created by calling a method on the C<AnyEvent> class.
67		124
		125	Many watchers either are used with "recursion" (repeating timers for
		126	example), or need to refer to their watcher object in other ways.
		127
		128	An any way to achieve that is this pattern:
		129
		130	my $w; $w = AnyEvent->type (arg => value ..., cb => sub {
		131	# you can use $w here, for example to undef it
		132	undef $w;
		133	});
		134
		135	Note that C<my $w; $w => combination. This is necessary because in Perl,
		136	my variables are only visible after the statement in which they are
		137	declared.
		138
68	=head2 IO WATCHERS	139	=head2 IO WATCHERS
69		140
70	You can create I/O watcher by calling the C<< AnyEvent->io >> method with	141	You can create an I/O watcher by calling the C<< AnyEvent->io >> method
71	the following mandatory arguments:	142	with the following mandatory key-value pairs as arguments:
72		143
73	C<fh> the Perl I<filehandle> (not filedescriptor) to watch for	144	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	145	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	146	creates a watcher waiting for "r"eadable or "w"ritable events,
76	to invoke everytime the filehandle becomes ready.	147	respectively. C<cb> is the callback to invoke each time the file handle
		148	becomes ready.
77		149
78	Only one io watcher per C<fh> and C<poll> combination is allowed (i.e. on
79	a socket you can have one r + one w, not any more (limitation comes from
80	Tk - if you are sure you are not using Tk this limitation is gone).
81
82	Filehandles will be kept alive, so as long as the watcher exists, the	150	File handles will be kept alive, so as long as the watcher exists, the
83	filehandle exists, too.	151	file handle exists, too.
		152
		153	It is not allowed to close a file handle as long as any watcher is active
		154	on the underlying file descriptor.
		155
		156	Some event loops issue spurious readyness notifications, so you should
		157	always use non-blocking calls when reading/writing from/to your file
		158	handles.
84		159
85	Example:	160	Example:
86		161
87	# wait for readability of STDIN, then read a line and disable the watcher	162	# 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 {	163	my $w; $w = AnyEvent->io (fh => \*STDIN, poll => 'r', cb => sub {
89	chomp (my $input = <STDIN>);	164	chomp (my $input = <STDIN>);
90	warn "read: $input\n";	165	warn "read: $input\n";
91	undef $w;	166	undef $w;
92	});	167	});
93		168
94	=head2 TIMER WATCHERS	169	=head2 TIME WATCHERS
95		170
96	You can create a timer watcher by calling the C<< AnyEvent->timer >>	171	You can create a time watcher by calling the C<< AnyEvent->timer >>
97	method with the following mandatory arguments:	172	method with the following mandatory arguments:
98		173
99	C<after> after how many seconds (fractions are supported) should the timer	174	C<after> specifies after how many seconds (fractional values are
100	activate. C<cb> the callback to invoke.	175	supported) should the timer activate. C<cb> the callback to invoke in that
		176	case.
101		177
102	The timer callback will be invoked at most once: if you want a repeating	178	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	179	timer you have to create a new watcher (this is a limitation by both Tk
104	and Glib).	180	and Glib).
105		181
…		…
109	my $w = AnyEvent->timer (after => 7.7, cb => sub {	185	my $w = AnyEvent->timer (after => 7.7, cb => sub {
110	warn "timeout\n";	186	warn "timeout\n";
111	});	187	});
112		188
113	# to cancel the timer:	189	# to cancel the timer:
114	undef $w	190	undef $w;
115		191
		192	Example 2:
		193
		194	# fire an event after 0.5 seconds, then roughly every second
		195	my $w;
		196
		197	my $cb = sub {
		198	# cancel the old timer while creating a new one
		199	$w = AnyEvent->timer (after => 1, cb => $cb);
		200	};
		201
		202	# start the "loop" by creating the first watcher
		203	$w = AnyEvent->timer (after => 0.5, cb => $cb);
		204
		205	=head3 TIMING ISSUES
		206
		207	There are two ways to handle timers: based on real time (relative, "fire
		208	in 10 seconds") and based on wallclock time (absolute, "fire at 12
		209	o'clock").
		210
		211	While most event loops expect timers to specified in a relative way, they use
		212	absolute time internally. This makes a difference when your clock "jumps",
		213	for example, when ntp decides to set your clock backwards from the wrong 2014-01-01 to
		214	2008-01-01, a watcher that you created to fire "after" a second might actually take
		215	six years to finally fire.
		216
		217	AnyEvent cannot compensate for this. The only event loop that is conscious
		218	about these issues is L<EV>, which offers both relative (ev_timer) and
		219	absolute (ev_periodic) timers.
		220
		221	AnyEvent always prefers relative timers, if available, matching the
		222	AnyEvent API.
		223
		224	=head2 SIGNAL WATCHERS
		225
		226	You can watch for signals using a signal watcher, C<signal> is the signal
		227	I<name> without any C<SIG> prefix, C<cb> is the Perl callback to
		228	be invoked whenever a signal occurs.
		229
		230	Multiple signals occurances can be clumped together into one callback
		231	invocation, and callback invocation will be synchronous. synchronous means
		232	that it might take a while until the signal gets handled by the process,
		233	but it is guarenteed not to interrupt any other callbacks.
		234
		235	The main advantage of using these watchers is that you can share a signal
		236	between multiple watchers.
		237
		238	This watcher might use C<%SIG>, so programs overwriting those signals
		239	directly will likely not work correctly.
		240
		241	Example: exit on SIGINT
		242
		243	my $w = AnyEvent->signal (signal => "INT", cb => sub { exit 1 });
		244
		245	=head2 CHILD PROCESS WATCHERS
		246
		247	You can also watch on a child process exit and catch its exit status.
		248
		249	The child process is specified by the C<pid> argument (if set to C<0>, it
		250	watches for any child process exit). The watcher will trigger as often
		251	as status change for the child are received. This works by installing a
		252	signal handler for C<SIGCHLD>. The callback will be called with the pid
		253	and exit status (as returned by waitpid).
		254
		255	Example: wait for pid 1333
		256
		257	my $w = AnyEvent->child (
		258	pid => 1333,
		259	cb => sub {
		260	my ($pid, $status) = @_;
		261	warn "pid $pid exited with status $status";
		262	},
		263	);
		264
116	=head2 CONDITION WATCHERS	265	=head2 CONDITION VARIABLES
117		266
118	Condition watchers can be created by calling the C<< AnyEvent->condvar >>	267	Condition variables can be created by calling the C<< AnyEvent->condvar >>
119	method without any arguments.	268	method without any arguments.
120		269
121	A condition watcher watches for a condition - precisely that the C<<	270	A condition variable waits for a condition - precisely that the C<<
122	->broadcast >> method has been called.	271	->broadcast >> method has been called.
123		272
124	The watcher has only two methods:	273	They are very useful to signal that a condition has been fulfilled, for
		274	example, if you write a module that does asynchronous http requests,
		275	then a condition variable would be the ideal candidate to signal the
		276	availability of results.
		277
		278	You can also use condition variables to block your main program until
		279	an event occurs - for example, you could C<< ->wait >> in your main
		280	program until the user clicks the Quit button in your app, which would C<<
		281	->broadcast >> the "quit" event.
		282
		283	Note that condition variables recurse into the event loop - if you have
		284	two pirces of code that call C<< ->wait >> in a round-robbin fashion, you
		285	lose. Therefore, condition variables are good to export to your caller, but
		286	you should avoid making a blocking wait yourself, at least in callbacks,
		287	as this asks for trouble.
		288
		289	This object has two methods:
125		290
126	=over 4	291	=over 4
127		292
128	=item $cv->wait	293	=item $cv->wait
129		294
130	Wait (blocking if necessary) until the C<< ->broadcast >> method has been	295	Wait (blocking if necessary) until the C<< ->broadcast >> method has been
131	called on c<$cv>, while servicing other watchers normally.	296	called on c<$cv>, while servicing other watchers normally.
132		297
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	298	You can only wait once on a condition - additional calls will return
141	immediately.	299	immediately.
142		300
		301	Not all event models support a blocking wait - some die in that case
		302	(programs might want to do that to stay interactive), so I<if you are
		303	using this from a module, never require a blocking wait>, but let the
		304	caller decide whether the call will block or not (for example, by coupling
		305	condition variables with some kind of request results and supporting
		306	callbacks so the caller knows that getting the result will not block,
		307	while still suppporting blocking waits if the caller so desires).
		308
		309	Another reason I<never> to C<< ->wait >> in a module is that you cannot
		310	sensibly have two C<< ->wait >>'s in parallel, as that would require
		311	multiple interpreters or coroutines/threads, none of which C<AnyEvent>
		312	can supply (the coroutine-aware backends L<AnyEvent::Impl::CoroEV> and
		313	L<AnyEvent::Impl::CoroEvent> explicitly support concurrent C<< ->wait >>'s
		314	from different coroutines, however).
		315
143	=item $cv->broadcast	316	=item $cv->broadcast
144		317
145	Flag the condition as ready - a running C<< ->wait >> and all further	318	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	319	calls to C<wait> will (eventually) return after this method has been
147	is waiting the broadcast will be remembered..	320	called. If nobody is waiting the broadcast will be remembered..
		321
		322	=back
148		323
149	Example:	324	Example:
150		325
151	# wait till the result is ready	326	# wait till the result is ready
152	my $result_ready = AnyEvent->condvar;	327	my $result_ready = AnyEvent->condvar;
153		328
154	# do something such as adding a timer	329	# do something such as adding a timer
155	# or socket watcher the calls $result_ready->broadcast	330	# or socket watcher the calls $result_ready->broadcast
156	# when the "result" is ready.	331	# when the "result" is ready.
		332	# in this case, we simply use a timer:
		333	my $w = AnyEvent->timer (
		334	after => 1,
		335	cb => sub { $result_ready->broadcast },
		336	);
157		337
		338	# this "blocks" (while handling events) till the watcher
		339	# calls broadcast
158	$result_ready->wait;	340	$result_ready->wait;
159		341
160	=back	342	=head1 GLOBAL VARIABLES AND FUNCTIONS
161
162	=head1 GLOBALS
163		343
164	=over 4	344	=over 4
165		345
166	=item $AnyEvent::MODEL	346	=item $AnyEvent::MODEL
167		347
…		…
171	C<AnyEvent::Impl:xxx> modules, but can be any other class in the case	351	C<AnyEvent::Impl:xxx> modules, but can be any other class in the case
172	AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode>).	352	AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode>).
173		353
174	The known classes so far are:	354	The known classes so far are:
175		355
176	AnyEvent::Impl::Coro based on Coro::Event, best choise.	356	AnyEvent::Impl::CoroEV based on Coro::EV, best choice.
		357	AnyEvent::Impl::CoroEvent based on Coro::Event, second best choice.
		358	AnyEvent::Impl::EV based on EV (an interface to libev, also best choice).
177	AnyEvent::Impl::Event based on Event, also best choice :)	359	AnyEvent::Impl::Event based on Event, also second best choice :)
178	AnyEvent::Impl::Glib based on Glib, second-best choice.	360	AnyEvent::Impl::Glib based on Glib, third-best choice.
179	AnyEvent::Impl::Tk based on Tk, very bad choice.	361	AnyEvent::Impl::Tk based on Tk, very bad choice.
180	AnyEvent::Impl::Perl pure-perl implementation, inefficient.	362	AnyEvent::Impl::Perl pure-perl implementation, inefficient but portable.
		363	AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse.
		364
		365	=item AnyEvent::detect
		366
		367	Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model
		368	if necessary. You should only call this function right before you would
		369	have created an AnyEvent watcher anyway, that is, as late as possible at
		370	runtime.
181		371
182	=back	372	=back
183		373
184	=head1 WHAT TO DO IN A MODULE	374	=head1 WHAT TO DO IN A MODULE
185		375
186	As a module author, you should "use AnyEvent" and call AnyEvent methods	376	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.	377	freely, but you should not load a specific event module or rely on it.
188		378
189	Be careful when you create watchers in the module body - Anyevent will	379	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	380	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	381	by calling AnyEvent in your module body you force the user of your module
192	to load the event module first.	382	to load the event module first.
193		383
		384	Never call C<< ->wait >> on a condition variable unless you I<know> that
		385	the C<< ->broadcast >> method has been called on it already. This is
		386	because it will stall the whole program, and the whole point of using
		387	events is to stay interactive.
		388
		389	It is fine, however, to call C<< ->wait >> when the user of your module
		390	requests it (i.e. if you create a http request object ad have a method
		391	called C<results> that returns the results, it should call C<< ->wait >>
		392	freely, as the user of your module knows what she is doing. always).
		393
194	=head1 WHAT TO DO IN THE MAIN PROGRAM	394	=head1 WHAT TO DO IN THE MAIN PROGRAM
195		395
196	There will always be a single main program - the only place that should	396	There will always be a single main program - the only place that should
197	dictate which event model to use.	397	dictate which event model to use.
198		398
199	If it doesn't care, it can just "use AnyEvent" and use it itself, or not	399	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.	400	do anything special (it does not need to be event-based) and let AnyEvent
		401	decide which implementation to chose if some module relies on it.
201		402
202	If the main program relies on a specific event model (for example, in Gtk2	403	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	404	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	405	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	406	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	407	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	408	decide on the event model to use as soon as it creates watchers, and it
208	correct one yourself.	409	might chose the wrong one unless you load the correct one yourself.
209		410
210	You can chose to use a rather inefficient pure-perl implementation by	411	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	412	loading the C<AnyEvent::Impl::Perl> module, which gives you similar
212	generally better.	413	behaviour everywhere, but letting AnyEvent chose is generally better.
213		414
214	=cut	415	=cut
215		416
216	package AnyEvent;	417	package AnyEvent;
217		418
218	no warnings;	419	no warnings;
219	use strict 'vars';	420	use strict;
		421
220	use Carp;	422	use Carp;
221		423
222	our $VERSION = '2.0';	424	our $VERSION = '3.12';
223	our $MODEL;	425	our $MODEL;
224		426
225	our $AUTOLOAD;	427	our $AUTOLOAD;
226	our @ISA;	428	our @ISA;
227		429
228	our $verbose = $ENV{PERL_ANYEVENT_VERBOSE}*1;	430	our $verbose = $ENV{PERL_ANYEVENT_VERBOSE}*1;
229		431
230	our @REGISTRY;	432	our @REGISTRY;
231		433
232	my @models = (	434	my @models = (
		435	[Coro::EV:: => AnyEvent::Impl::CoroEV::],
233	[Coro::Event:: => AnyEvent::Impl::Coro::],	436	[Coro::Event:: => AnyEvent::Impl::CoroEvent::],
		437	[EV:: => AnyEvent::Impl::EV::],
234	[Event:: => AnyEvent::Impl::Event::],	438	[Event:: => AnyEvent::Impl::Event::],
235	[Glib:: => AnyEvent::Impl::Glib::],	439	[Glib:: => AnyEvent::Impl::Glib::],
236	[Tk:: => AnyEvent::Impl::Tk::],	440	[Tk:: => AnyEvent::Impl::Tk::],
237	[AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl::],	441	[AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl::],
		442	[Event::Lib:: => AnyEvent::Impl::EventLib::],
238	);	443	);
239		444
240	our %method = map +($_ => 1), qw(io timer condvar broadcast wait DESTROY);	445	our %method = map +($_ => 1), qw(io timer condvar broadcast wait signal one_event DESTROY);
241		446
242	sub AUTOLOAD {	447	sub detect() {
243	$AUTOLOAD =~ s/.*://;
244
245	$method{$AUTOLOAD}
246	or croak "$AUTOLOAD: not a valid method for AnyEvent objects";
247
248	unless ($MODEL) {	448	unless ($MODEL) {
		449	no strict 'refs';
		450
		451	if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) {
		452	my $model = "AnyEvent::Impl::$1";
		453	if (eval "require $model") {
		454	$MODEL = $model;
		455	warn "AnyEvent: loaded model '$model' (forced by \$PERL_ANYEVENT_MODEL), using it.\n" if $verbose > 1;
		456	}
		457	}
		458
249	# check for already loaded models	459	# check for already loaded models
		460	unless ($MODEL) {
250	for (@REGISTRY, @models) {	461	for (@REGISTRY, @models) {
251	my ($package, $model) = @$_;	462	my ($package, $model) = @$_;
252	if (${"$package\::VERSION"} > 0) {	463	if (${"$package\::VERSION"} > 0) {
253	if (eval "require $model") {	464	if (eval "require $model") {
254	$MODEL = $model;	465	$MODEL = $model;
255	warn "AnyEvent: found model '$model', using it.\n" if $verbose > 1;	466	warn "AnyEvent: autodetected model '$model', using it.\n" if $verbose > 1;
256	last;	467	last;
		468	}
257	}	469	}
258	}	470	}
		471
		472	unless ($MODEL) {
		473	# try to load a model
		474
		475	for (@REGISTRY, @models) {
		476	my ($package, $model) = @$_;
		477	if (eval "require $package"
		478	and ${"$package\::VERSION"} > 0
		479	and eval "require $model") {
		480	$MODEL = $model;
		481	warn "AnyEvent: autoprobed model '$model', using it.\n" if $verbose > 1;
		482	last;
		483	}
		484	}
		485
		486	$MODEL
		487	or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV (or Coro+EV), Event (or Coro+Event) or Glib.";
		488	}
259	}	489	}
260		490
261	unless ($MODEL) {	491	unshift @ISA, $MODEL;
262	# try to load a model	492	push @{"$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	}	493	}
277		494
278	@ISA = $MODEL;	495	$MODEL
		496	}
		497
		498	sub AUTOLOAD {
		499	(my $func = $AUTOLOAD) =~ s/.*://;
		500
		501	$method{$func}
		502	or croak "$func: not a valid method for AnyEvent objects";
		503
		504	detect unless $MODEL;
279		505
280	my $class = shift;	506	my $class = shift;
281	$class->$AUTOLOAD (@_);	507	$class->$func (@_);
		508	}
		509
		510	package AnyEvent::Base;
		511
		512	# default implementation for ->condvar, ->wait, ->broadcast
		513
		514	sub condvar {
		515	bless \my $flag, "AnyEvent::Base::CondVar"
		516	}
		517
		518	sub AnyEvent::Base::CondVar::broadcast {
		519	${$_[0]}++;
		520	}
		521
		522	sub AnyEvent::Base::CondVar::wait {
		523	AnyEvent->one_event while !${$_[0]};
		524	}
		525
		526	# default implementation for ->signal
		527
		528	our %SIG_CB;
		529
		530	sub signal {
		531	my (undef, %arg) = @_;
		532
		533	my $signal = uc $arg{signal}
		534	or Carp::croak "required option 'signal' is missing";
		535
		536	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};
		537	$SIG{$signal} \|\|= sub {
		538	$_->() for values %{ $SIG_CB{$signal} \|\| {} };
		539	};
		540
		541	bless [$signal, $arg{cb}], "AnyEvent::Base::Signal"
		542	}
		543
		544	sub AnyEvent::Base::Signal::DESTROY {
		545	my ($signal, $cb) = @{$_[0]};
		546
		547	delete $SIG_CB{$signal}{$cb};
		548
		549	$SIG{$signal} = 'DEFAULT' unless keys %{ $SIG_CB{$signal} };
		550	}
		551
		552	# default implementation for ->child
		553
		554	our %PID_CB;
		555	our $CHLD_W;
		556	our $CHLD_DELAY_W;
		557	our $PID_IDLE;
		558	our $WNOHANG;
		559
		560	sub _child_wait {
		561	while (0 < (my $pid = waitpid -1, $WNOHANG)) {
		562	$_->($pid, $?) for (values %{ $PID_CB{$pid} \|\| {} }),
		563	(values %{ $PID_CB{0} \|\| {} });
		564	}
		565
		566	undef $PID_IDLE;
		567	}
		568
		569	sub _sigchld {
		570	# make sure we deliver these changes "synchronous" with the event loop.
		571	$CHLD_DELAY_W \|\|= AnyEvent->timer (after => 0, cb => sub {
		572	undef $CHLD_DELAY_W;
		573	&_child_wait;
		574	});
		575	}
		576
		577	sub child {
		578	my (undef, %arg) = @_;
		579
		580	defined (my $pid = $arg{pid} + 0)
		581	or Carp::croak "required option 'pid' is missing";
		582
		583	$PID_CB{$pid}{$arg{cb}} = $arg{cb};
		584
		585	unless ($WNOHANG) {
		586	$WNOHANG = eval { require POSIX; &POSIX::WNOHANG } \|\| 1;
		587	}
		588
		589	unless ($CHLD_W) {
		590	$CHLD_W = AnyEvent->signal (signal => 'CHLD', cb => \&_sigchld);
		591	# child could be a zombie already, so make at least one round
		592	&_sigchld;
		593	}
		594
		595	bless [$pid, $arg{cb}], "AnyEvent::Base::Child"
		596	}
		597
		598	sub AnyEvent::Base::Child::DESTROY {
		599	my ($pid, $cb) = @{$_[0]};
		600
		601	delete $PID_CB{$pid}{$cb};
		602	delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };
		603
		604	undef $CHLD_W unless keys %PID_CB;
282	}	605	}
283		606
284	=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE	607	=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE
		608
		609	This is an advanced topic that you do not normally need to use AnyEvent in
		610	a module. This section is only of use to event loop authors who want to
		611	provide AnyEvent compatibility.
285		612
286	If you need to support another event library which isn't directly	613	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	614	supported by AnyEvent, you can supply your own interface to it by
288	pushing, before the first watcher gets created, the package name of	615	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	616	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	617	C<@AnyEvent::REGISTRY>. You can do that before and even without loading
291	AnyEvent.	618	AnyEvent, so it is reasonably cheap.
292		619
293	Example:	620	Example:
294		621
295	push @AnyEvent::REGISTRY, [urxvt => urxvt::anyevent::];	622	push @AnyEvent::REGISTRY, [urxvt => urxvt::anyevent::];
296		623
297	This tells AnyEvent to (literally) use the C<urxvt::anyevent::>	624	This tells AnyEvent to (literally) use the C<urxvt::anyevent::>
298	package/class when it finds the C<urxvt> package/module is loaded. When	625	package/class when it finds the C<urxvt> package/module is already loaded.
		626
299	AnyEvent is loaded and asked to find a suitable event model, it will	627	When AnyEvent is loaded and asked to find a suitable event model, it
300	first check for the presence of urxvt.	628	will first check for the presence of urxvt by trying to C<use> the
		629	C<urxvt::anyevent> module.
301		630
302	The class should prove implementations for all watcher types (see	631	The class should provide implementations for all watcher types. See
303	L<AnyEvent::Impl::Event> (source code), L<AnyEvent::Impl::Glib>	632	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	633	and so on for actual examples. Use C<perldoc -m AnyEvent::Impl::Glib> to
305	AnyEvent::Impl::Glib> to see the sources).	634	see the sources.
306		635
		636	If you don't provide C<signal> and C<child> watchers than AnyEvent will
		637	provide suitable (hopefully) replacements.
		638
307	The above isn't fictitious, the I<rxvt-unicode> (a.k.a. urxvt)	639	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	640	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	641	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	642	inside I<rxvt-unicode>, and it is updated and maintained as part of the
311	I<rxvt-unicode> distribution.	643	I<rxvt-unicode> distribution.
312		644
313	I<rxvt-unicode> also cheats a bit by not providing blocking access to	645	I<rxvt-unicode> also cheats a bit by not providing blocking access to
314	condition variables: code blocking while waiting for a condition will	646	condition variables: code blocking while waiting for a condition will
315	C<die>. This still works with most modules/usages, and blocking calls must	647	C<die>. This still works with most modules/usages, and blocking calls must
316	not be in an interactive appliation, so it makes sense.	648	not be done in an interactive application, so it makes sense.
317		649
318	=head1 ENVIRONMENT VARIABLES	650	=head1 ENVIRONMENT VARIABLES
319		651
320	The following environment variables are used by this module:	652	The following environment variables are used by this module:
321		653
322	C<PERL_ANYEVENT_VERBOSE> when set to C<2> or higher, reports which event	654	=over 4
323	model gets used.
324		655
		656	=item C<PERL_ANYEVENT_VERBOSE>
		657
		658	When set to C<2> or higher, cause AnyEvent to report to STDERR which event
		659	model it chooses.
		660
		661	=item C<PERL_ANYEVENT_MODEL>
		662
		663	This can be used to specify the event model to be used by AnyEvent, before
		664	autodetection and -probing kicks in. It must be a string consisting
		665	entirely of ASCII letters. The string C<AnyEvent::Impl::> gets prepended
		666	and the resulting module name is loaded and if the load was successful,
		667	used as event model. If it fails to load AnyEvent will proceed with
		668	autodetection and -probing.
		669
		670	This functionality might change in future versions.
		671
		672	For example, to force the pure perl model (L<AnyEvent::Impl::Perl>) you
		673	could start your program like this:
		674
		675	PERL_ANYEVENT_MODEL=Perl perl ...
		676
		677	=back
		678
325	=head1 EXAMPLE	679	=head1 EXAMPLE PROGRAM
326		680
327	The following program uses an io watcher to read data from stdin, a timer	681	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	682	to display a message once per second, and a condition variable to quit the
329	when the user enters quit:	683	program when the user enters quit:
330		684
331	use AnyEvent;	685	use AnyEvent;
332		686
333	my $cv = AnyEvent->condvar;	687	my $cv = AnyEvent->condvar;
334		688
335	my $io_watcher = AnyEvent->io (fh => \*STDIN, poll => 'r', cb => sub {	689	my $io_watcher = AnyEvent->io (
		690	fh => \*STDIN,
		691	poll => 'r',
		692	cb => sub {
336	warn "io event <$_[0]>\n"; # will always output <r>	693	warn "io event <$_[0]>\n"; # will always output <r>
337	chomp (my $input = <STDIN>); # read a line	694	chomp (my $input = <STDIN>); # read a line
338	warn "read: $input\n"; # output what has been read	695	warn "read: $input\n"; # output what has been read
339	$cv->broadcast if $input =~ /^q/i; # quit program if /^q/i	696	$cv->broadcast if $input =~ /^q/i; # quit program if /^q/i
		697	},
340	});	698	);
341		699
342	my $time_watcher; # can only be used once	700	my $time_watcher; # can only be used once
343		701
344	sub new_timer {	702	sub new_timer {
345	$timer = AnyEvent->timer (after => 1, cb => sub {	703	$timer = AnyEvent->timer (after => 1, cb => sub {
…		…
427	$txn->{finished}->wait;	785	$txn->{finished}->wait;
428	return $txn->{result};	786	return $txn->{result};
429		787
430	The actual code goes further and collects all errors (C<die>s, exceptions)	788	The actual code goes further and collects all errors (C<die>s, exceptions)
431	that occured during request processing. The C<result> method detects	789	that occured during request processing. The C<result> method detects
432	wether an exception as thrown (it is stored inside the $txn object)	790	whether an exception as thrown (it is stored inside the $txn object)
433	and just throws the exception, which means connection errors and other	791	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	792	problems get reported tot he code that tries to use the result, not in a
435	random callback.	793	random callback.
436		794
437	All of this enables the following usage styles:	795	All of this enables the following usage styles:
438		796
439	1. Blocking:	797	1. Blocking:
440		798
441	my $data = $fcp->client_get ($url);	799	my $data = $fcp->client_get ($url);
442		800
443	2. Blocking, but parallelizing:	801	2. Blocking, but running in parallel:
444		802
445	my @datas = map $_->result,	803	my @datas = map $_->result,
446	map $fcp->txn_client_get ($_),	804	map $fcp->txn_client_get ($_),
447	@urls;	805	@urls;
448		806
449	Both blocking examples work without the module user having to know	807	Both blocking examples work without the module user having to know
450	anything about events.	808	anything about events.
451		809
452	3a. Event-based in a main program, using any support Event module:	810	3a. Event-based in a main program, using any supported event module:
453		811
454	use Event;	812	use EV;
455		813
456	$fcp->txn_client_get ($url)->cb (sub {	814	$fcp->txn_client_get ($url)->cb (sub {
457	my $txn = shift;	815	my $txn = shift;
458	my $data = $txn->result;	816	my $data = $txn->result;
459	...	817	...
460	});	818	});
461		819
462	Event::loop;	820	EV::loop;
463		821
464	3b. The module user could use AnyEvent, too:	822	3b. The module user could use AnyEvent, too:
465		823
466	use AnyEvent;	824	use AnyEvent;
467		825
…		…
472	$quit->broadcast;	830	$quit->broadcast;
473	});	831	});
474		832
475	$quit->wait;	833	$quit->wait;
476		834
		835	=head1 FORK
		836
		837	Most event libraries are not fork-safe. The ones who are usually are
		838	because they are so inefficient. Only L<EV> is fully fork-aware.
		839
		840	If you have to fork, you must either do so I<before> creating your first
		841	watcher OR you must not use AnyEvent at all in the child.
		842
		843	=head1 SECURITY CONSIDERATIONS
		844
		845	AnyEvent can be forced to load any event model via
		846	$ENV{PERL_ANYEVENT_MODEL}. While this cannot (to my knowledge) be used to
		847	execute arbitrary code or directly gain access, it can easily be used to
		848	make the program hang or malfunction in subtle ways, as AnyEvent watchers
		849	will not be active when the program uses a different event model than
		850	specified in the variable.
		851
		852	You can make AnyEvent completely ignore this variable by deleting it
		853	before the first watcher gets created, e.g. with a C<BEGIN> block:
		854
		855	BEGIN { delete $ENV{PERL_ANYEVENT_MODEL} }
		856
		857	use AnyEvent;
		858
477	=head1 SEE ALSO	859	=head1 SEE ALSO
478		860
479	Event modules: L<Coro::Event>, L<Coro>, L<Event>, L<Glib::Event>, L<Glib>.	861	Event modules: L<Coro::EV>, L<EV>, L<EV::Glib>, L<Glib::EV>,
		862	L<Coro::Event>, L<Event>, L<Glib::Event>, L<Glib>, L<Coro>, L<Tk>,
		863	L<Event::Lib>.
480		864
		865	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>.	866	L<AnyEvent::Impl::CoroEvent>, L<AnyEvent::Impl::Event>, L<AnyEvent::Impl::Glib>,
		867	L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>, L<AnyEvent::Impl::EventLib>.
482		868
483	Nontrivial usage example: L<Net::FCP>.	869	Nontrivial usage examples: L<Net::FCP>, L<Net::XMPP2>.
484		870
485	=head1	871	=head1 AUTHOR
		872
		873	Marc Lehmann <schmorp@schmorp.de>
		874	http://home.schmorp.de/
486		875
487	=cut	876	=cut
488		877
489	1	878	1
490		879

Diff Legend

-–
+Removed lines
-+
+Added lines
-<
+Changed lines
->
+Changed lines

Comparing AnyEvent/lib/AnyEvent.pm (file contents): Revision 1.16 by root, Sun Nov 5 01:08:16 2006 UTC vs. Revision 1.55 by root, Wed Apr 23 11:25:42 2008 UTC

Diff Legend

Comparing AnyEvent/lib/AnyEvent.pm (file contents):
Revision 1.16 by root, Sun Nov 5 01:08:16 2006 UTC vs.
Revision 1.55 by root, Wed Apr 23 11:25:42 2008 UTC