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

Comparing AnyEvent/lib/AnyEvent.pm (file contents):
Revision 1.6 by root, Mon Dec 19 17:03:29 2005 UTC vs.
Revision 1.54 by root, Tue Apr 22 05:12:19 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 - various supported event loops	5	EV, Event, Coro::EV, Coro::Event, Glib, Tk, Perl - various supported event loops
6		6
7	=head1 SYNOPSIS	7	=head1 SYNOPSIS
8		8
9	use AnyEvent;	9	use AnyEvent;
10		10
11	my $w = AnyEvent->io (fh => ..., poll => "[rw]+", cb => sub {	11	my $w = AnyEvent->io (fh => $fh, poll => "r\|w", cb => sub {
12	my ($poll_got) = @_;
13	...	12	...
14	});	13	});
15
16	- only one io watcher per $fh and $poll type is allowed
17	(i.e. on a socket you can have one r + one w or one rw
18	watcher, not any more.
19
20	- AnyEvent will keep filehandles alive, so as long as the watcher exists,
21	the filehandle exists.
22		14
23	my $w = AnyEvent->timer (after => $seconds, cb => sub {	15	my $w = AnyEvent->timer (after => $seconds, cb => sub {
24	...	16	...
25	});	17	});
26		18
27	- io and time watchers get canceled whenever $w is destroyed, so keep a copy	19	my $w = AnyEvent->condvar; # stores whether a condition was flagged
28
29	- timers can only be used once and must be recreated for repeated operation
30
31	my $w = AnyEvent->condvar; # kind of main loop replacement
32	$w->wait; # enters main loop till $condvar gets ->broadcast	20	$w->wait; # enters "main loop" till $condvar gets ->broadcast
33	$w->broadcast; # wake up current and all future wait's	21	$w->broadcast; # wake up current and all future wait's
34		22
35	- condvars are used to give blocking behaviour when neccessary. Create	23	=head1 WHY YOU SHOULD USE THIS MODULE (OR NOT)
36	a condvar for any "request" or "event" your module might create, C<<	24
37	->broadcast >> it when the event happens and provide a function that calls	25	Glib, POE, IO::Async, Event... CPAN offers event models by the dozen
38	C<< ->wait >> for it. See the examples below.	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
39		71
40	=head1 DESCRIPTION	72	=head1 DESCRIPTION
41		73
42	L<AnyEvent> provides an identical interface to multiple event loops. This	74	L<AnyEvent> provides an identical interface to multiple event loops. This
43	allows module authors to utilizy an event loop without forcing module	75	allows module authors to utilise an event loop without forcing module
44	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
45	peacefully at any one time).	77	peacefully at any one time).
46		78
47	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>
48	module.	80	module.
49		81
50	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
51	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
52	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>,
53	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,
54	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
55	used. If still none could be found, it will issue an error.	87	that can be successfully loaded will be used. If, after this, still none
		88	could be found, AnyEvent will fall back to a pure-perl event loop, which
		89	is not very efficient, but should work everywhere.
		90
		91	Because AnyEvent first checks for modules that are already loaded, loading
		92	an event model explicitly before first using AnyEvent will likely make
		93	that model the default. For example:
		94
		95	use Tk;
		96	use AnyEvent;
		97
		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...
		103
		104	The pure-perl implementation of AnyEvent is called
		105	C<AnyEvent::Impl::Perl>. Like other event modules you can load it
		106	explicitly.
		107
		108	=head1 WATCHERS
		109
		110	AnyEvent has the central concept of a I<watcher>, which is an object that
		111	stores relevant data for each kind of event you are waiting for, such as
		112	the callback to call, the filehandle to watch, etc.
		113
		114	These watchers are normal Perl objects with normal Perl lifetime. After
		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
		119	To disable the watcher you have to destroy it (e.g. by setting the
		120	variable you store it in to C<undef> or otherwise deleting all references
		121	to it).
		122
		123	All watchers are created by calling a method on the C<AnyEvent> class.
		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
		139	=head2 IO WATCHERS
		140
		141	You can create an I/O watcher by calling the C<< AnyEvent->io >> method
		142	with the following mandatory key-value pairs as arguments:
		143
		144	C<fh> the Perl I<file handle> (I<not> file descriptor) to watch for
		145	events. C<poll> must be a string that is either C<r> or C<w>, which
		146	creates a watcher waiting for "r"eadable or "w"ritable events,
		147	respectively. C<cb> is the callback to invoke each time the file handle
		148	becomes ready.
		149
		150	File handles will be kept alive, so as long as the watcher exists, the
		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.
		159
		160	Example:
		161
		162	# wait for readability of STDIN, then read a line and disable the watcher
		163	my $w; $w = AnyEvent->io (fh => \*STDIN, poll => 'r', cb => sub {
		164	chomp (my $input = <STDIN>);
		165	warn "read: $input\n";
		166	undef $w;
		167	});
		168
		169	=head2 TIME WATCHERS
		170
		171	You can create a time watcher by calling the C<< AnyEvent->timer >>
		172	method with the following mandatory arguments:
		173
		174	C<after> specifies after how many seconds (fractional values are
		175	supported) should the timer activate. C<cb> the callback to invoke in that
		176	case.
		177
		178	The timer callback will be invoked at most once: if you want a repeating
		179	timer you have to create a new watcher (this is a limitation by both Tk
		180	and Glib).
		181
		182	Example:
		183
		184	# fire an event after 7.7 seconds
		185	my $w = AnyEvent->timer (after => 7.7, cb => sub {
		186	warn "timeout\n";
		187	});
		188
		189	# to cancel the timer:
		190	undef $w;
		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
		265	=head2 CONDITION VARIABLES
		266
		267	Condition variables can be created by calling the C<< AnyEvent->condvar >>
		268	method without any arguments.
		269
		270	A condition variable waits for a condition - precisely that the C<<
		271	->broadcast >> method has been called.
		272
		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:
56		290
57	=over 4	291	=over 4
58		292
		293	=item $cv->wait
		294
		295	Wait (blocking if necessary) until the C<< ->broadcast >> method has been
		296	called on c<$cv>, while servicing other watchers normally.
		297
		298	You can only wait once on a condition - additional calls will return
		299	immediately.
		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
		316	=item $cv->broadcast
		317
		318	Flag the condition as ready - a running C<< ->wait >> and all further
		319	calls to C<wait> will (eventually) return after this method has been
		320	called. If nobody is waiting the broadcast will be remembered..
		321
		322	=back
		323
		324	Example:
		325
		326	# wait till the result is ready
		327	my $result_ready = AnyEvent->condvar;
		328
		329	# do something such as adding a timer
		330	# or socket watcher the calls $result_ready->broadcast
		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	);
		337
		338	# this "blocks" (while handling events) till the watcher
		339	# calls broadcast
		340	$result_ready->wait;
		341
		342	=head1 GLOBAL VARIABLES AND FUNCTIONS
		343
		344	=over 4
		345
		346	=item $AnyEvent::MODEL
		347
		348	Contains C<undef> until the first watcher is being created. Then it
		349	contains the event model that is being used, which is the name of the
		350	Perl class implementing the model. This class is usually one of the
		351	C<AnyEvent::Impl:xxx> modules, but can be any other class in the case
		352	AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode>).
		353
		354	The known classes so far are:
		355
		356	AnyEvent::Impl::CoroEV based on Coro::EV, best choice.
		357	AnyEvent::Impl::CoroEvent based on Coro::Event, second best choice.
		358	AnyEvent::Impl::EV based on EV (an interface to libev, also best choice).
		359	AnyEvent::Impl::Event based on Event, also second best choice :)
		360	AnyEvent::Impl::Glib based on Glib, third-best choice.
		361	AnyEvent::Impl::Tk based on Tk, very bad choice.
		362	AnyEvent::Impl::Perl pure-perl implementation, inefficient but portable.
		363
		364	=item AnyEvent::detect
		365
		366	Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model
		367	if necessary. You should only call this function right before you would
		368	have created an AnyEvent watcher anyway, that is, as late as possible at
		369	runtime.
		370
		371	=back
		372
		373	=head1 WHAT TO DO IN A MODULE
		374
		375	As a module author, you should C<use AnyEvent> and call AnyEvent methods
		376	freely, but you should not load a specific event module or rely on it.
		377
		378	Be careful when you create watchers in the module body - AnyEvent will
		379	decide which event module to use as soon as the first method is called, so
		380	by calling AnyEvent in your module body you force the user of your module
		381	to load the event module first.
		382
		383	Never call C<< ->wait >> on a condition variable unless you I<know> that
		384	the C<< ->broadcast >> method has been called on it already. This is
		385	because it will stall the whole program, and the whole point of using
		386	events is to stay interactive.
		387
		388	It is fine, however, to call C<< ->wait >> when the user of your module
		389	requests it (i.e. if you create a http request object ad have a method
		390	called C<results> that returns the results, it should call C<< ->wait >>
		391	freely, as the user of your module knows what she is doing. always).
		392
		393	=head1 WHAT TO DO IN THE MAIN PROGRAM
		394
		395	There will always be a single main program - the only place that should
		396	dictate which event model to use.
		397
		398	If it doesn't care, it can just "use AnyEvent" and use it itself, or not
		399	do anything special (it does not need to be event-based) and let AnyEvent
		400	decide which implementation to chose if some module relies on it.
		401
		402	If the main program relies on a specific event model. For example, in
		403	Gtk2 programs you have to rely on the Glib module. You should load the
		404	event module before loading AnyEvent or any module that uses it: generally
		405	speaking, you should load it as early as possible. The reason is that
		406	modules might create watchers when they are loaded, and AnyEvent will
		407	decide on the event model to use as soon as it creates watchers, and it
		408	might chose the wrong one unless you load the correct one yourself.
		409
		410	You can chose to use a rather inefficient pure-perl implementation by
		411	loading the C<AnyEvent::Impl::Perl> module, which gives you similar
		412	behaviour everywhere, but letting AnyEvent chose is generally better.
		413
59	=cut	414	=cut
60		415
61	package AnyEvent;	416	package AnyEvent;
62		417
63	no warnings;	418	no warnings;
64	use strict 'vars';	419	use strict;
		420
65	use Carp;	421	use Carp;
66		422
67	our $VERSION = 0.3;	423	our $VERSION = '3.12';
68	our $MODEL;	424	our $MODEL;
69		425
70	our $AUTOLOAD;	426	our $AUTOLOAD;
71	our @ISA;	427	our @ISA;
72		428
		429	our $verbose = $ENV{PERL_ANYEVENT_VERBOSE}*1;
		430
		431	our @REGISTRY;
		432
73	my @models = (	433	my @models = (
74	[Coro => Coro::Event::],	434	[Coro::EV:: => AnyEvent::Impl::CoroEV::],
75	[Event => Event::],	435	[Coro::Event:: => AnyEvent::Impl::CoroEvent::],
76	[Glib => Glib::],	436	[EV:: => AnyEvent::Impl::EV::],
77	[Tk => Tk::],	437	[Event:: => AnyEvent::Impl::Event::],
		438	[Glib:: => AnyEvent::Impl::Glib::],
		439	[Tk:: => AnyEvent::Impl::Tk::],
		440	[AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl::],
78	);	441	);
79		442
80	our %method = map +($_ => 1), qw(io timer condvar broadcast wait cancel DESTROY);	443	our %method = map +($_ => 1), qw(io timer condvar broadcast wait signal one_event DESTROY);
81		444
82	sub AUTOLOAD {	445	sub detect() {
83	$AUTOLOAD =~ s/.*://;
84
85	$method{$AUTOLOAD}
86	or croak "$AUTOLOAD: not a valid method for AnyEvent objects";
87
88	unless ($MODEL) {	446	unless ($MODEL) {
		447	no strict 'refs';
		448
89	# check for already loaded models	449	# check for already loaded models
90	for (@models) {	450	for (@REGISTRY, @models) {
91	my ($model, $package) = @$_;	451	my ($package, $model) = @$_;
92	if (scalar keys %{ *{"$package\::"} }) {	452	if (${"$package\::VERSION"} > 0) {
93	eval "require AnyEvent::Impl::$model";	453	if (eval "require $model") {
94	last if $MODEL;	454	$MODEL = $model;
		455	warn "AnyEvent: found model '$model', using it.\n" if $verbose > 1;
		456	last;
		457	}
95	}	458	}
96	}	459	}
97		460
98	unless ($MODEL) {	461	unless ($MODEL) {
99	# try to load a model	462	# try to load a model
100		463
101	for (@models) {	464	for (@REGISTRY, @models) {
102	my ($model, $package) = @$_;	465	my ($package, $model) = @$_;
103	eval "require AnyEvent::Impl::$model";	466	if (eval "require $package"
104	last if $MODEL;	467	and ${"$package\::VERSION"} > 0
		468	and eval "require $model") {
		469	$MODEL = $model;
		470	warn "AnyEvent: autoprobed and loaded model '$model', using it.\n" if $verbose > 1;
		471	last;
		472	}
105	}	473	}
106		474
107	$MODEL	475	$MODEL
108	or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: Coro, Event, Glib or Tk.";	476	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), Glib or Tk.";
109	}	477	}
		478
		479	unshift @ISA, $MODEL;
		480	push @{"$MODEL\::ISA"}, "AnyEvent::Base";
110	}	481	}
111		482
112	@ISA = $MODEL;	483	$MODEL
		484	}
		485
		486	sub AUTOLOAD {
		487	(my $func = $AUTOLOAD) =~ s/.*://;
		488
		489	$method{$func}
		490	or croak "$func: not a valid method for AnyEvent objects";
		491
		492	detect unless $MODEL;
113		493
114	my $class = shift;	494	my $class = shift;
115	$class->$AUTOLOAD (@_);	495	$class->$func (@_);
116	}	496	}
117		497
118	=back	498	package AnyEvent::Base;
119		499
		500	# default implementation for ->condvar, ->wait, ->broadcast
		501
		502	sub condvar {
		503	bless \my $flag, "AnyEvent::Base::CondVar"
		504	}
		505
		506	sub AnyEvent::Base::CondVar::broadcast {
		507	${$_[0]}++;
		508	}
		509
		510	sub AnyEvent::Base::CondVar::wait {
		511	AnyEvent->one_event while !${$_[0]};
		512	}
		513
		514	# default implementation for ->signal
		515
		516	our %SIG_CB;
		517
		518	sub signal {
		519	my (undef, %arg) = @_;
		520
		521	my $signal = uc $arg{signal}
		522	or Carp::croak "required option 'signal' is missing";
		523
		524	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};
		525	$SIG{$signal} \|\|= sub {
		526	$_->() for values %{ $SIG_CB{$signal} \|\| {} };
		527	};
		528
		529	bless [$signal, $arg{cb}], "AnyEvent::Base::Signal"
		530	}
		531
		532	sub AnyEvent::Base::Signal::DESTROY {
		533	my ($signal, $cb) = @{$_[0]};
		534
		535	delete $SIG_CB{$signal}{$cb};
		536
		537	$SIG{$signal} = 'DEFAULT' unless keys %{ $SIG_CB{$signal} };
		538	}
		539
		540	# default implementation for ->child
		541
		542	our %PID_CB;
		543	our $CHLD_W;
		544	our $CHLD_DELAY_W;
		545	our $PID_IDLE;
		546	our $WNOHANG;
		547
		548	sub _child_wait {
		549	while (0 < (my $pid = waitpid -1, $WNOHANG)) {
		550	$_->($pid, $?) for (values %{ $PID_CB{$pid} \|\| {} }),
		551	(values %{ $PID_CB{0} \|\| {} });
		552	}
		553
		554	undef $PID_IDLE;
		555	}
		556
		557	sub _sigchld {
		558	# make sure we deliver these changes "synchronous" with the event loop.
		559	$CHLD_DELAY_W \|\|= AnyEvent->timer (after => 0, cb => sub {
		560	undef $CHLD_DELAY_W;
		561	&_child_wait;
		562	});
		563	}
		564
		565	sub child {
		566	my (undef, %arg) = @_;
		567
		568	defined (my $pid = $arg{pid} + 0)
		569	or Carp::croak "required option 'pid' is missing";
		570
		571	$PID_CB{$pid}{$arg{cb}} = $arg{cb};
		572
		573	unless ($WNOHANG) {
		574	$WNOHANG = eval { require POSIX; &POSIX::WNOHANG } \|\| 1;
		575	}
		576
		577	unless ($CHLD_W) {
		578	$CHLD_W = AnyEvent->signal (signal => 'CHLD', cb => \&_sigchld);
		579	# child could be a zombie already, so make at least one round
		580	&_sigchld;
		581	}
		582
		583	bless [$pid, $arg{cb}], "AnyEvent::Base::Child"
		584	}
		585
		586	sub AnyEvent::Base::Child::DESTROY {
		587	my ($pid, $cb) = @{$_[0]};
		588
		589	delete $PID_CB{$pid}{$cb};
		590	delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };
		591
		592	undef $CHLD_W unless keys %PID_CB;
		593	}
		594
		595	=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE
		596
		597	This is an advanced topic that you do not normally need to use AnyEvent in
		598	a module. This section is only of use to event loop authors who want to
		599	provide AnyEvent compatibility.
		600
		601	If you need to support another event library which isn't directly
		602	supported by AnyEvent, you can supply your own interface to it by
		603	pushing, before the first watcher gets created, the package name of
		604	the event module and the package name of the interface to use onto
		605	C<@AnyEvent::REGISTRY>. You can do that before and even without loading
		606	AnyEvent, so it is reasonably cheap.
		607
		608	Example:
		609
		610	push @AnyEvent::REGISTRY, [urxvt => urxvt::anyevent::];
		611
		612	This tells AnyEvent to (literally) use the C<urxvt::anyevent::>
		613	package/class when it finds the C<urxvt> package/module is already loaded.
		614
		615	When AnyEvent is loaded and asked to find a suitable event model, it
		616	will first check for the presence of urxvt by trying to C<use> the
		617	C<urxvt::anyevent> module.
		618
		619	The class should provide implementations for all watcher types. See
		620	L<AnyEvent::Impl::EV> (source code), L<AnyEvent::Impl::Glib> (Source code)
		621	and so on for actual examples. Use C<perldoc -m AnyEvent::Impl::Glib> to
		622	see the sources.
		623
		624	If you don't provide C<signal> and C<child> watchers than AnyEvent will
		625	provide suitable (hopefully) replacements.
		626
		627	The above example isn't fictitious, the I<rxvt-unicode> (a.k.a. urxvt)
		628	terminal emulator uses the above line as-is. An interface isn't included
		629	in AnyEvent because it doesn't make sense outside the embedded interpreter
		630	inside I<rxvt-unicode>, and it is updated and maintained as part of the
		631	I<rxvt-unicode> distribution.
		632
		633	I<rxvt-unicode> also cheats a bit by not providing blocking access to
		634	condition variables: code blocking while waiting for a condition will
		635	C<die>. This still works with most modules/usages, and blocking calls must
		636	not be done in an interactive application, so it makes sense.
		637
		638	=head1 ENVIRONMENT VARIABLES
		639
		640	The following environment variables are used by this module:
		641
		642	C<PERL_ANYEVENT_VERBOSE> when set to C<2> or higher, cause AnyEvent to
		643	report to STDERR which event model it chooses.
		644
120	=head1 EXAMPLE	645	=head1 EXAMPLE PROGRAM
121		646
122	The following program uses an io watcher to read data from stdin, a timer	647	The following program uses an IO watcher to read data from STDIN, a timer
123	to display a message once per second, and a condvar to exit the program	648	to display a message once per second, and a condition variable to quit the
124	when the user enters quit:	649	program when the user enters quit:
125		650
126	use AnyEvent;	651	use AnyEvent;
127		652
128	my $cv = AnyEvent->condvar;	653	my $cv = AnyEvent->condvar;
129		654
130	my $io_watcher = AnyEvent->io (fh => \*STDIN, poll => 'r', cb => sub {	655	my $io_watcher = AnyEvent->io (
		656	fh => \*STDIN,
		657	poll => 'r',
		658	cb => sub {
131	warn "io event <$_[0]>\n"; # will always output <r>	659	warn "io event <$_[0]>\n"; # will always output <r>
132	chomp (my $input = <STDIN>); # read a line	660	chomp (my $input = <STDIN>); # read a line
133	warn "read: $input\n"; # output what has been read	661	warn "read: $input\n"; # output what has been read
134	$cv->broadcast if $input =~ /^q/i; # quit program if /^q/i	662	$cv->broadcast if $input =~ /^q/i; # quit program if /^q/i
		663	},
135	});	664	);
136		665
137	my $time_watcher; # can only be used once	666	my $time_watcher; # can only be used once
138		667
139	sub new_timer {	668	sub new_timer {
140	$timer = AnyEvent->timer (after => 1, cb => sub {	669	$timer = AnyEvent->timer (after => 1, cb => sub {
222	$txn->{finished}->wait;	751	$txn->{finished}->wait;
223	return $txn->{result};	752	return $txn->{result};
224		753
225	The actual code goes further and collects all errors (C<die>s, exceptions)	754	The actual code goes further and collects all errors (C<die>s, exceptions)
226	that occured during request processing. The C<result> method detects	755	that occured during request processing. The C<result> method detects
227	wether an exception as thrown (it is stored inside the $txn object)	756	whether an exception as thrown (it is stored inside the $txn object)
228	and just throws the exception, which means connection errors and other	757	and just throws the exception, which means connection errors and other
229	problems get reported tot he code that tries to use the result, not in a	758	problems get reported tot he code that tries to use the result, not in a
230	random callback.	759	random callback.
231		760
232	All of this enables the following usage styles:	761	All of this enables the following usage styles:
233		762
234	1. Blocking:	763	1. Blocking:
235		764
236	my $data = $fcp->client_get ($url);	765	my $data = $fcp->client_get ($url);
237		766
238	2. Blocking, but parallelizing:	767	2. Blocking, but running in parallel:
239		768
240	my @datas = map $_->result,	769	my @datas = map $_->result,
241	map $fcp->txn_client_get ($_),	770	map $fcp->txn_client_get ($_),
242	@urls;	771	@urls;
243		772
244	Both blocking examples work without the module user having to know	773	Both blocking examples work without the module user having to know
245	anything about events.	774	anything about events.
246		775
247	3a. Event-based in a main program, using any support Event module:	776	3a. Event-based in a main program, using any supported event module:
248		777
249	use Event;	778	use EV;
250		779
251	$fcp->txn_client_get ($url)->cb (sub {	780	$fcp->txn_client_get ($url)->cb (sub {
252	my $txn = shift;	781	my $txn = shift;
253	my $data = $txn->result;	782	my $data = $txn->result;
254	...	783	...
255	});	784	});
256		785
257	Event::loop;	786	EV::loop;
258		787
259	3b. The module user could use AnyEvent, too:	788	3b. The module user could use AnyEvent, too:
260		789
261	use AnyEvent;	790	use AnyEvent;
262		791
…		…
269		798
270	$quit->wait;	799	$quit->wait;
271		800
272	=head1 SEE ALSO	801	=head1 SEE ALSO
273		802
274	Event modules: L<Coro::Event>, L<Coro>, L<Event>, L<Glib::Event>, L<Glib>.	803	Event modules: L<Coro::EV>, L<EV>, L<EV::Glib>, L<Glib::EV>,
		804	L<Coro::Event>, L<Event>, L<Glib::Event>, L<Glib>, L<Coro>, L<Tk>.
275		805
276	Implementations: L<AnyEvent::Impl::Coro>, L<AnyEvent::Impl::Event>, L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>.	806	Implementations: L<AnyEvent::Impl::CoroEV>, L<AnyEvent::Impl::EV>,
		807	L<AnyEvent::Impl::CoroEvent>, L<AnyEvent::Impl::Event>,
		808	L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>.
277		809
278	Nontrivial usage example: L<Net::FCP>.	810	Nontrivial usage examples: L<Net::FCP>, L<Net::XMPP2>.
279		811
280	=head1	812	=head1 AUTHOR
		813
		814	Marc Lehmann <schmorp@schmorp.de>
		815	http://home.schmorp.de/
281		816
282	=cut	817	=cut
283		818
284	1	819	1
285		820

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Revision 1.54 by root, Tue Apr 22 05:12:19 2008 UTC