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

Comparing AnyEvent/lib/AnyEvent.pm (file contents):
Revision 1.7 by root, Fri Dec 30 01:28:31 2005 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 - 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
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 $poll type is allowed (i.e. on a socket
17	you can have one r + one w or one rw watcher, not any more (limitation by
18	Tk).
19
20	* the C<$poll_got> passed to the handler needs to be checked by looking
21	for single characters (e.g. with a regex), as it can contain more event
22	types than were requested (e.g. a 'w' watcher might generate 'rw' events,
23	limitation by Glib).
24
25	* AnyEvent will keep filehandles alive, so as long as the watcher exists,
26	the filehandle exists.
27		14
28	my $w = AnyEvent->timer (after => $seconds, cb => sub {	15	my $w = AnyEvent->timer (after => $seconds, cb => sub {
29	...	16	...
30	});	17	});
31		18
32	* 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
33
34	* timers can only be used once and must be recreated for repeated
35	operation (limitation by Glib and Tk).
36
37	my $w = AnyEvent->condvar; # kind of main loop replacement
38	$w->wait; # enters main loop till $condvar gets ->broadcast	20	$w->wait; # enters "main loop" till $condvar gets ->broadcast
39	$w->broadcast; # wake up current and all future wait's	21	$w->broadcast; # wake up current and all future wait's
40		22
41	* condvars are used to give blocking behaviour when neccessary. Create	23	=head1 WHY YOU SHOULD USE THIS MODULE (OR NOT)
42	a condvar for any "request" or "event" your module might create, C<<	24
43	->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
44	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
45		71
46	=head1 DESCRIPTION	72	=head1 DESCRIPTION
47		73
48	L<AnyEvent> provides an identical interface to multiple event loops. This	74	L<AnyEvent> provides an identical interface to multiple event loops. This
49	allows module authors to utilizy an event loop without forcing module	75	allows module authors to utilise an event loop without forcing module
50	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
51	peacefully at any one time).	77	peacefully at any one time).
52		78
53	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>
54	module.	80	module.
55		81
56	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
57	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
58	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
59	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
60	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
61	used. If still none could be found, it will issue an error.	88	be successfully loaded will be used. If, after this, still none could be
		89	found, AnyEvent will fall back to a pure-perl event loop, which is not
		90	very efficient, but should work everywhere.
		91
		92	Because AnyEvent first checks for modules that are already loaded, loading
		93	an event model explicitly before first using AnyEvent will likely make
		94	that model the default. For example:
		95
		96	use Tk;
		97	use AnyEvent;
		98
		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...
		104
		105	The pure-perl implementation of AnyEvent is called
		106	C<AnyEvent::Impl::Perl>. Like other event modules you can load it
		107	explicitly.
		108
		109	=head1 WATCHERS
		110
		111	AnyEvent has the central concept of a I<watcher>, which is an object that
		112	stores relevant data for each kind of event you are waiting for, such as
		113	the callback to call, the filehandle to watch, etc.
		114
		115	These watchers are normal Perl objects with normal Perl lifetime. After
		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
		120	To disable the watcher you have to destroy it (e.g. by setting the
		121	variable you store it in to C<undef> or otherwise deleting all references
		122	to it).
		123
		124	All watchers are created by calling a method on the C<AnyEvent> class.
		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
		140	=head2 IO WATCHERS
		141
		142	You can create an I/O watcher by calling the C<< AnyEvent->io >> method
		143	with the following mandatory key-value pairs as arguments:
		144
		145	C<fh> the Perl I<file handle> (I<not> file descriptor) to watch for
		146	events. C<poll> must be a string that is either C<r> or C<w>, which
		147	creates a watcher waiting for "r"eadable or "w"ritable events,
		148	respectively. C<cb> is the callback to invoke each time the file handle
		149	becomes ready.
		150
		151	As long as the I/O watcher exists it will keep the file descriptor or a
		152	copy of it alive/open.
		153
		154	It is not allowed to close a file handle as long as any watcher is active
		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.
		160
		161	Example:
		162
		163	# wait for readability of STDIN, then read a line and disable the watcher
		164	my $w; $w = AnyEvent->io (fh => \*STDIN, poll => 'r', cb => sub {
		165	chomp (my $input = <STDIN>);
		166	warn "read: $input\n";
		167	undef $w;
		168	});
		169
		170	=head2 TIME WATCHERS
		171
		172	You can create a time watcher by calling the C<< AnyEvent->timer >>
		173	method with the following mandatory arguments:
		174
		175	C<after> specifies after how many seconds (fractional values are
		176	supported) should the timer activate. C<cb> the callback to invoke in that
		177	case.
		178
		179	The timer callback will be invoked at most once: if you want a repeating
		180	timer you have to create a new watcher (this is a limitation by both Tk
		181	and Glib).
		182
		183	Example:
		184
		185	# fire an event after 7.7 seconds
		186	my $w = AnyEvent->timer (after => 7.7, cb => sub {
		187	warn "timeout\n";
		188	});
		189
		190	# to cancel the timer:
		191	undef $w;
		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
		267	=head2 CONDITION VARIABLES
		268
		269	Condition variables can be created by calling the C<< AnyEvent->condvar >>
		270	method without any arguments.
		271
		272	A condition variable waits for a condition - precisely that the C<<
		273	->broadcast >> method has been called.
		274
		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:
62		292
63	=over 4	293	=over 4
64		294
		295	=item $cv->wait
		296
		297	Wait (blocking if necessary) until the C<< ->broadcast >> method has been
		298	called on c<$cv>, while servicing other watchers normally.
		299
		300	You can only wait once on a condition - additional calls will return
		301	immediately.
		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
		318	=item $cv->broadcast
		319
		320	Flag the condition as ready - a running C<< ->wait >> and all further
		321	calls to C<wait> will (eventually) return after this method has been
		322	called. If nobody is waiting the broadcast will be remembered..
		323
		324	=back
		325
		326	Example:
		327
		328	# wait till the result is ready
		329	my $result_ready = AnyEvent->condvar;
		330
		331	# do something such as adding a timer
		332	# or socket watcher the calls $result_ready->broadcast
		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	);
		339
		340	# this "blocks" (while handling events) till the watcher
		341	# calls broadcast
		342	$result_ready->wait;
		343
		344	=head1 GLOBAL VARIABLES AND FUNCTIONS
		345
		346	=over 4
		347
		348	=item $AnyEvent::MODEL
		349
		350	Contains C<undef> until the first watcher is being created. Then it
		351	contains the event model that is being used, which is the name of the
		352	Perl class implementing the model. This class is usually one of the
		353	C<AnyEvent::Impl:xxx> modules, but can be any other class in the case
		354	AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode>).
		355
		356	The known classes so far are:
		357
		358	AnyEvent::Impl::CoroEV based on Coro::EV, best choice.
		359	AnyEvent::Impl::CoroEvent based on Coro::Event, second best choice.
		360	AnyEvent::Impl::EV based on EV (an interface to libev, best choice).
		361	AnyEvent::Impl::Event based on Event, second best choice.
		362	AnyEvent::Impl::Glib based on Glib, third-best choice.
		363	AnyEvent::Impl::Tk based on Tk, very bad choice.
		364	AnyEvent::Impl::Perl pure-perl implementation, inefficient but portable.
		365	AnyEvent::Impl::Qt based on Qt, cannot be autoprobed (see its docs).
		366	AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse.
		367
		368	=item AnyEvent::detect
		369
		370	Returns C<$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.
		374
		375	=back
		376
		377	=head1 WHAT TO DO IN A MODULE
		378
		379	As a module author, you should C<use AnyEvent> and call AnyEvent methods
		380	freely, but you should not load a specific event module or rely on it.
		381
		382	Be careful when you create watchers in the module body - AnyEvent will
		383	decide which event module to use as soon as the first method is called, so
		384	by calling AnyEvent in your module body you force the user of your module
		385	to load the event module first.
		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
		397	=head1 WHAT TO DO IN THE MAIN PROGRAM
		398
		399	There will always be a single main program - the only place that should
		400	dictate which event model to use.
		401
		402	If it doesn't care, it can just "use AnyEvent" and use it itself, or not
		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.
		405
		406	If the main program relies on a specific event model. For example, in
		407	Gtk2 programs you have to rely on the Glib module. You should load the
		408	event module before loading AnyEvent or any module that uses it: generally
		409	speaking, you should load it as early as possible. The reason is that
		410	modules might create watchers when they are loaded, and AnyEvent will
		411	decide on the event model to use as soon as it creates watchers, and it
		412	might chose the wrong one unless you load the correct one yourself.
		413
		414	You can chose to use a rather inefficient pure-perl implementation by
		415	loading the C<AnyEvent::Impl::Perl> module, which gives you similar
		416	behaviour everywhere, but letting AnyEvent chose is generally better.
		417
65	=cut	418	=cut
66		419
67	package AnyEvent;	420	package AnyEvent;
68		421
69	no warnings;	422	no warnings;
70	use strict 'vars';	423	use strict;
		424
71	use Carp;	425	use Carp;
72		426
73	our $VERSION = '0.4';	427	our $VERSION = '3.2';
74	our $MODEL;	428	our $MODEL;
75		429
76	our $AUTOLOAD;	430	our $AUTOLOAD;
77	our @ISA;	431	our @ISA;
78		432
79	our $verbose = $ENV{PERL_ANYEVENT_VERBOSE}*1;	433	our $verbose = $ENV{PERL_ANYEVENT_VERBOSE}*1;
80		434
		435	our @REGISTRY;
		436
81	my @models = (	437	my @models = (
82	[Coro => Coro::Event::],	438	[Coro::EV:: => AnyEvent::Impl::CoroEV::],
83	[Event => Event::],	439	[Coro::Event:: => AnyEvent::Impl::CoroEvent::],
84	[Glib => Glib::],	440	[EV:: => AnyEvent::Impl::EV::],
85	[Tk => Tk::],	441	[Event:: => AnyEvent::Impl::Event::],
		442	[Glib:: => AnyEvent::Impl::Glib::],
		443	[Tk:: => AnyEvent::Impl::Tk::],
		444	[AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl::],
86	);	445	);
		446	my @models_detect = (
		447	[Qt:: => AnyEvent::Impl::Qt::], # requires special main program
		448	[Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy
		449	);
87		450
88	our %method = map +($_ => 1), qw(io timer condvar broadcast wait cancel DESTROY);	451	our %method = map +($_ => 1), qw(io timer signal child condvar broadcast wait one_event DESTROY);
89		452
90	sub AUTOLOAD {	453	sub detect() {
91	$AUTOLOAD =~ s/.*://;
92
93	$method{$AUTOLOAD}
94	or croak "$AUTOLOAD: not a valid method for AnyEvent objects";
95
96	unless ($MODEL) {	454	unless ($MODEL) {
97	# check for already loaded models	455	no strict 'refs';
98	for (@models) {	456
99	my ($model, $package) = @$_;	457	if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) {
100	if (${"$package\::VERSION"} > 0) {	458	my $model = "AnyEvent::Impl::$1";
101	eval "require AnyEvent::Impl::$model";	459	if (eval "require $model") {
102	warn "AnyEvent: found model '$model', using it.\n" if $MODEL && $verbose > 1;	460	$MODEL = $model;
103	last if $MODEL;	461	warn "AnyEvent: loaded model '$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 $verbose;
104	}	464	}
105	}	465	}
106		466
		467	# check for already loaded models
107	unless ($MODEL) {	468	unless ($MODEL) {
108	# try to load a model	469	for (@REGISTRY, @models, @models_detect) {
109
110	for (@models) {
111	my ($model, $package) = @$_;	470	my ($package, $model) = @$_;
112	eval "require AnyEvent::Impl::$model";	471	if (${"$package\::VERSION"} > 0) {
		472	if (eval "require $model") {
		473	$MODEL = $model;
113	warn "AnyEvent: autprobed and loaded model '$model', using it.\n" if $MODEL && $verbose > 1;	474	warn "AnyEvent: autodetected model '$model', using it.\n" if $verbose > 1;
114	last if $MODEL;	475	last;
		476	}
		477	}
115	}	478	}
116		479
		480	unless ($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
117	$MODEL	494	$MODEL
118	or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: Coro, Event, Glib or Tk.";	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	}
119	}	497	}
		498
		499	unshift @ISA, $MODEL;
		500	push @{"$MODEL\::ISA"}, "AnyEvent::Base";
120	}	501	}
121		502
122	@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;
123		513
124	my $class = shift;	514	my $class = shift;
125	$class->$AUTOLOAD (@_);	515	$class->$func (@_);
126	}	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;
		613	}
		614
		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.
		620
		621	If you need to support another event library which isn't directly
		622	supported by AnyEvent, you can supply your own interface to it by
		623	pushing, before the first watcher gets created, the package name of
		624	the event module and the package name of the interface to use onto
		625	C<@AnyEvent::REGISTRY>. You can do that before and even without loading
		626	AnyEvent, so it is reasonably cheap.
		627
		628	Example:
		629
		630	push @AnyEvent::REGISTRY, [urxvt => urxvt::anyevent::];
		631
		632	This tells AnyEvent to (literally) use the C<urxvt::anyevent::>
		633	package/class when it finds the C<urxvt> package/module is already loaded.
		634
		635	When AnyEvent is loaded and asked to find a suitable event model, it
		636	will first check for the presence of urxvt by trying to C<use> the
		637	C<urxvt::anyevent> module.
		638
		639	The class should provide implementations for all watcher types. See
		640	L<AnyEvent::Impl::EV> (source code), L<AnyEvent::Impl::Glib> (Source code)
		641	and so on for actual examples. Use C<perldoc -m AnyEvent::Impl::Glib> to
		642	see the sources.
		643
		644	If you don't provide C<signal> and C<child> watchers than AnyEvent will
		645	provide suitable (hopefully) replacements.
		646
		647	The above example isn't fictitious, the I<rxvt-unicode> (a.k.a. urxvt)
		648	terminal emulator uses the above line as-is. An interface isn't included
		649	in AnyEvent because it doesn't make sense outside the embedded interpreter
		650	inside I<rxvt-unicode>, and it is updated and maintained as part of the
		651	I<rxvt-unicode> distribution.
		652
		653	I<rxvt-unicode> also cheats a bit by not providing blocking access to
		654	condition variables: code blocking while waiting for a condition will
		655	C<die>. This still works with most modules/usages, and blocking calls must
		656	not be done in an interactive application, so it makes sense.
		657
		658	=head1 ENVIRONMENT VARIABLES
		659
		660	The following environment variables are used by this module:
		661
		662	=over 4
		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 ...
127		692
128	=back	693	=back
129		694
130	=head1 ENVIRONMENT VARIABLES
131
132	The following environment variables are used by this module:
133
134	C<PERL_ANYEVENT_VERBOSE> when set to C<2> or higher, reports which event
135	model gets used.
136
137	=head1 EXAMPLE	695	=head1 EXAMPLE PROGRAM
138		696
139	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
140	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
141	when the user enters quit:	699	program when the user enters quit:
142		700
143	use AnyEvent;	701	use AnyEvent;
144		702
145	my $cv = AnyEvent->condvar;	703	my $cv = AnyEvent->condvar;
146		704
147	my $io_watcher = AnyEvent->io (fh => \*STDIN, poll => 'r', cb => sub {	705	my $io_watcher = AnyEvent->io (
		706	fh => \*STDIN,
		707	poll => 'r',
		708	cb => sub {
148	warn "io event <$_[0]>\n"; # will always output <r>	709	warn "io event <$_[0]>\n"; # will always output <r>
149	chomp (my $input = <STDIN>); # read a line	710	chomp (my $input = <STDIN>); # read a line
150	warn "read: $input\n"; # output what has been read	711	warn "read: $input\n"; # output what has been read
151	$cv->broadcast if $input =~ /^q/i; # quit program if /^q/i	712	$cv->broadcast if $input =~ /^q/i; # quit program if /^q/i
		713	},
152	});	714	);
153		715
154	my $time_watcher; # can only be used once	716	my $time_watcher; # can only be used once
155		717
156	sub new_timer {	718	sub new_timer {
157	$timer = AnyEvent->timer (after => 1, cb => sub {	719	$timer = AnyEvent->timer (after => 1, cb => sub {
239	$txn->{finished}->wait;	801	$txn->{finished}->wait;
240	return $txn->{result};	802	return $txn->{result};
241		803
242	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)
243	that occured during request processing. The C<result> method detects	805	that occured during request processing. The C<result> method detects
244	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)
245	and just throws the exception, which means connection errors and other	807	and just throws the exception, which means connection errors and other
246	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
247	random callback.	809	random callback.
248		810
249	All of this enables the following usage styles:	811	All of this enables the following usage styles:
250		812
251	1. Blocking:	813	1. Blocking:
252		814
253	my $data = $fcp->client_get ($url);	815	my $data = $fcp->client_get ($url);
254		816
255	2. Blocking, but parallelizing:	817	2. Blocking, but running in parallel:
256		818
257	my @datas = map $_->result,	819	my @datas = map $_->result,
258	map $fcp->txn_client_get ($_),	820	map $fcp->txn_client_get ($_),
259	@urls;	821	@urls;
260		822
261	Both blocking examples work without the module user having to know	823	Both blocking examples work without the module user having to know
262	anything about events.	824	anything about events.
263		825
264	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:
265		827
266	use Event;	828	use EV;
267		829
268	$fcp->txn_client_get ($url)->cb (sub {	830	$fcp->txn_client_get ($url)->cb (sub {
269	my $txn = shift;	831	my $txn = shift;
270	my $data = $txn->result;	832	my $data = $txn->result;
271	...	833	...
272	});	834	});
273		835
274	Event::loop;	836	EV::loop;
275		837
276	3b. The module user could use AnyEvent, too:	838	3b. The module user could use AnyEvent, too:
277		839
278	use AnyEvent;	840	use AnyEvent;
279		841
…		…
284	$quit->broadcast;	846	$quit->broadcast;
285	});	847	});
286		848
287	$quit->wait;	849	$quit->wait;
288		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
289	=head1 SEE ALSO	875	=head1 SEE ALSO
290		876
291	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>.
292		880
		881	Implementations: L<AnyEvent::Impl::CoroEV>, L<AnyEvent::Impl::EV>,
293	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>.
294		885
295	Nontrivial usage example: L<Net::FCP>.	886	Nontrivial usage examples: L<Net::FCP>, L<Net::XMPP2>.
296		887
297	=head1	888	=head1 AUTHOR
		889
		890	Marc Lehmann <schmorp@schmorp.de>
		891	http://home.schmorp.de/
298		892
299	=cut	893	=cut
300		894
301	1	895	1
302		896

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Comparing AnyEvent/lib/AnyEvent.pm (file contents): Revision 1.7 by root, Fri Dec 30 01:28:31 2005 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 1.7 by root, Fri Dec 30 01:28:31 2005 UTC vs.
Revision 1.60 by root, Fri Apr 25 01:05:26 2008 UTC