[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 1.20 by root, Mon Dec 11 01:16:09 2006 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	Event, Coro, 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 wether 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
36	a condvar for any "request" or "event" your module might create, C<<
37	->broadcast >> it when the event happens and provide a function that calls
38	C<< ->wait >> for it. See the examples below.
39
40	=head1 DESCRIPTION	23	=head1 DESCRIPTION
41		24
42	L<AnyEvent> provides an identical interface to multiple event loops. This	25	L<AnyEvent> provides an identical interface to multiple event loops. This
43	allows module authors to utilizy an event loop without forcing module	26	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	27	users to use the same event loop (as only a single event loop can coexist
45	peacefully at any one time).	28	peacefully at any one time).
46		29
47	The interface itself is vaguely similar but not identical to the Event	30	The interface itself is vaguely similar but not identical to the Event
48	module.	31	module.
50	On the first call of any method, the module tries to detect the currently	33	On the first call of any method, the module tries to detect the currently
51	loaded event loop by probing wether any of the following modules is	34	loaded event loop by probing wether any of the following modules is
52	loaded: L<Coro::Event>, L<Event>, L<Glib>, L<Tk>. The first one found is	35	loaded: L<Coro::Event>, L<Event>, L<Glib>, L<Tk>. The first one found is
53	used. If none is found, the module tries to load these modules in the	36	used. If none is found, the module tries to load these modules in the
54	order given. The first one that could be successfully loaded will be	37	order given. The first one that could be successfully loaded will be
55	used. If still none could be found, it will issue an error.	38	used. If still none could be found, AnyEvent will fall back to a pure-perl
		39	event loop, which is also not very efficient.
		40
		41	Because AnyEvent first checks for modules that are already loaded, loading
		42	an Event model explicitly before first using AnyEvent will likely make
		43	that model the default. For example:
		44
		45	use Tk;
		46	use AnyEvent;
		47
		48	# .. AnyEvent will likely default to Tk
		49
		50	The pure-perl implementation of AnyEvent is called
		51	C<AnyEvent::Impl::Perl>. Like other event modules you can load it
		52	explicitly.
		53
		54	=head1 WATCHERS
		55
		56	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
		58	the callback to call, the filehandle to watch, etc.
		59
		60	These watchers are normal Perl objects with normal Perl lifetime. After
		61	creating a watcher it will immediately "watch" for events and invoke
		62	the callback. To disable the watcher you have to destroy it (e.g. by
		63	setting the variable that stores it to C<undef> or otherwise deleting all
		64	references to it).
		65
		66	All watchers are created by calling a method on the C<AnyEvent> class.
		67
		68	=head2 IO WATCHERS
		69
		70	You can create I/O watcher by calling the C<< AnyEvent->io >> method with
		71	the following mandatory arguments:
		72
		73	C<fh> the Perl I<filehandle> (not filedescriptor) to watch for
		74	events. C<poll> must be a string that is either C<r> or C<w>, that creates
		75	a watcher waiting for "r"eadable or "w"ritable events. C<cb> teh callback
		76	to invoke everytime the filehandle becomes ready.
		77
		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
		83	filehandle exists, too.
		84
		85	Example:
		86
		87	# 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 {
		89	chomp (my $input = <STDIN>);
		90	warn "read: $input\n";
		91	undef $w;
		92	});
		93
		94	=head2 TIME WATCHERS
		95
		96	You can create a time watcher by calling the C<< AnyEvent->timer >>
		97	method with the following mandatory arguments:
		98
		99	C<after> after how many seconds (fractions are supported) should the timer
		100	activate. C<cb> the callback to invoke.
		101
		102	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
		104	and Glib).
		105
		106	Example:
		107
		108	# fire an event after 7.7 seconds
		109	my $w = AnyEvent->timer (after => 7.7, cb => sub {
		110	warn "timeout\n";
		111	});
		112
		113	# to cancel the timer:
		114	undef $w
		115
		116	=head2 CONDITION WATCHERS
		117
		118	Condition watchers can be created by calling the C<< AnyEvent->condvar >>
		119	method without any arguments.
		120
		121	A condition watcher watches for a condition - precisely that the C<<
		122	->broadcast >> method has been called.
		123
		124	The watcher has only two methods:
56		125
57	=over 4	126	=over 4
58		127
		128	=item $cv->wait
		129
		130	Wait (blocking if necessary) until the C<< ->broadcast >> method has been
		131	called on c<$cv>, while servicing other watchers normally.
		132
		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
		141	immediately.
		142
		143	=item $cv->broadcast
		144
		145	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
		147	is waiting the broadcast will be remembered..
		148
		149	Example:
		150
		151	# wait till the result is ready
		152	my $result_ready = AnyEvent->condvar;
		153
		154	# do something such as adding a timer
		155	# or socket watcher the calls $result_ready->broadcast
		156	# when the "result" is ready.
		157
		158	$result_ready->wait;
		159
		160	=back
		161
		162	=head2 SIGNAL WATCHERS
		163
		164	You can listen for signals using a signal watcher, C<signal> is the signal
		165	I<name> without any C<SIG> prefix. Multiple signals events can be clumped
		166	together into one callback invocation, and callbakc invocation might or
		167	might not be asynchronous.
		168
		169	These watchers might use C<%SIG>, so programs overwriting those signals
		170	directly will likely not work correctly.
		171
		172	Example: exit on SIGINT
		173
		174	my $w = AnyEvent->signal (signal => "INT", cb => sub { exit 1 });
		175
		176	=head2 CHILD PROCESS WATCHERS
		177
		178	You can also listen for the status of a child process specified by the
		179	C<pid> argument. The watcher will only trigger once. This works by
		180	installing a signal handler for C<SIGCHLD>.
		181
		182	Example: wait for pid 1333
		183
		184	my $w = AnyEvent->child (pid => 1333, cb => sub { warn "exit status $?" });
		185
		186	=head1 GLOBALS
		187
		188	=over 4
		189
		190	=item $AnyEvent::MODEL
		191
		192	Contains C<undef> until the first watcher is being created. Then it
		193	contains the event model that is being used, which is the name of the
		194	Perl class implementing the model. This class is usually one of the
		195	C<AnyEvent::Impl:xxx> modules, but can be any other class in the case
		196	AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode>).
		197
		198	The known classes so far are:
		199
		200	AnyEvent::Impl::Coro based on Coro::Event, best choise.
		201	AnyEvent::Impl::Event based on Event, also best choice :)
		202	AnyEvent::Impl::Glib based on Glib, second-best choice.
		203	AnyEvent::Impl::Tk based on Tk, very bad choice.
		204	AnyEvent::Impl::Perl pure-perl implementation, inefficient.
		205
		206	=item AnyEvent::detect
		207
		208	Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model if
		209	necessary. You should only call this function right before you would have
		210	created an AnyEvent watcher anyway, that is, very late at runtime.
		211
		212	=back
		213
		214	=head1 WHAT TO DO IN A MODULE
		215
		216	As a module author, you should "use AnyEvent" and call AnyEvent methods
		217	freely, but you should not load a specific event module or rely on it.
		218
		219	Be careful when you create watchers in the module body - Anyevent will
		220	decide which event module to use as soon as the first method is called, so
		221	by calling AnyEvent in your module body you force the user of your module
		222	to load the event module first.
		223
		224	=head1 WHAT TO DO IN THE MAIN PROGRAM
		225
		226	There will always be a single main program - the only place that should
		227	dictate which event model to use.
		228
		229	If it doesn't care, it can just "use AnyEvent" and use it itself, or not
		230	do anything special and let AnyEvent decide which implementation to chose.
		231
		232	If the main program relies on a specific event model (for example, in Gtk2
		233	programs you have to rely on either Glib or Glib::Event), you should load
		234	it before loading AnyEvent or any module that uses it, generally, as early
		235	as possible. The reason is that modules might create watchers when they
		236	are loaded, and AnyEvent will decide on the event model to use as soon as
		237	it creates watchers, and it might chose the wrong one unless you load the
		238	correct one yourself.
		239
		240	You can chose to use a rather inefficient pure-perl implementation by
		241	loading the C<AnyEvent::Impl::Perl> module, but letting AnyEvent chose is
		242	generally better.
		243
59	=cut	244	=cut
60		245
61	package AnyEvent;	246	package AnyEvent;
62		247
63	no warnings;	248	no warnings;
64	use strict 'vars';	249	use strict;
65	use Carp;	250	use Carp;
66		251
67	our $VERSION = 0.3;	252	our $VERSION = '2.5';
68	our $MODEL;	253	our $MODEL;
69		254
70	our $AUTOLOAD;	255	our $AUTOLOAD;
71	our @ISA;	256	our @ISA;
72		257
		258	our $verbose = $ENV{PERL_ANYEVENT_VERBOSE}*1;
		259
		260	our @REGISTRY;
		261
73	my @models = (	262	my @models = (
74	[Coro => Coro::Event::],	263	[Coro::Event:: => AnyEvent::Impl::Coro::],
75	[Event => Event::],	264	[Event:: => AnyEvent::Impl::Event::],
76	[Glib => Glib::],	265	[Glib:: => AnyEvent::Impl::Glib::],
77	[Tk => Tk::],	266	[Tk:: => AnyEvent::Impl::Tk::],
		267	[AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl::],
78	);	268	);
79		269
80	our %method = map +($_ => 1), qw(io timer condvar broadcast wait cancel DESTROY);	270	our %method = map +($_ => 1), qw(io timer condvar broadcast wait signal one_event DESTROY);
81		271
82	sub AUTOLOAD {	272	sub detect() {
83	$AUTOLOAD =~ s/.*://;
84
85	$method{$AUTOLOAD}
86	or croak "$AUTOLOAD: not a valid method for AnyEvent objects";
87
88	unless ($MODEL) {	273	unless ($MODEL) {
		274	no strict 'refs';
		275
89	# check for already loaded models	276	# check for already loaded models
90	for (@models) {	277	for (@REGISTRY, @models) {
91	my ($model, $package) = @$_;	278	my ($package, $model) = @$_;
92	if (scalar keys %{ *{"$package\::"} }) {	279	if (${"$package\::VERSION"} > 0) {
93	eval "require AnyEvent::Impl::$model";	280	if (eval "require $model") {
94	last if $MODEL;	281	$MODEL = $model;
		282	warn "AnyEvent: found model '$model', using it.\n" if $verbose > 1;
		283	last;
		284	}
95	}	285	}
96	}	286	}
97		287
98	unless ($MODEL) {	288	unless ($MODEL) {
99	# try to load a model	289	# try to load a model
100		290
101	for (@models) {	291	for (@REGISTRY, @models) {
102	my ($model, $package) = @$_;	292	my ($package, $model) = @$_;
103	eval "require AnyEvent::Impl::$model";	293	if (eval "require $model") {
104	last if $MODEL;	294	$MODEL = $model;
		295	warn "AnyEvent: autoprobed and loaded model '$model', using it.\n" if $verbose > 1;
		296	last;
		297	}
105	}	298	}
106		299
107	$MODEL	300	$MODEL
108	or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: Coro, Event, Glib or Tk.";	301	or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: Event (or Coro+Event), Glib or Tk.";
109	}	302	}
		303
		304	unshift @ISA, $MODEL;
		305	push @{"$MODEL\::ISA"}, "AnyEvent::Base";
110	}	306	}
111		307
112	@ISA = $MODEL;	308	$MODEL
		309	}
		310
		311	sub AUTOLOAD {
		312	(my $func = $AUTOLOAD) =~ s/.*://;
		313
		314	$method{$func}
		315	or croak "$func: not a valid method for AnyEvent objects";
		316
		317	detect unless $MODEL;
113		318
114	my $class = shift;	319	my $class = shift;
115	$class->$AUTOLOAD (@_);	320	$class->$func (@_);
116	}	321	}
117		322
118	=back	323	package AnyEvent::Base;
		324
		325	# default implementation for ->condvar, ->wait, ->broadcast
		326
		327	sub condvar {
		328	bless \my $flag, "AnyEvent::Base::CondVar"
		329	}
		330
		331	sub AnyEvent::Base::CondVar::broadcast {
		332	${$_[0]}++;
		333	}
		334
		335	sub AnyEvent::Base::CondVar::wait {
		336	AnyEvent->one_event while !${$_[0]};
		337	}
		338
		339	# default implementation for ->signal
		340
		341	our %SIG_CB;
		342
		343	sub signal {
		344	my (undef, %arg) = @_;
		345
		346	my $signal = uc $arg{signal}
		347	or Carp::croak "required option 'signal' is missing";
		348
		349	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};
		350	$SIG{$signal} \|\|= sub {
		351	$_->() for values %{ $SIG_CB{$signal} \|\| {} };
		352	};
		353
		354	bless [$signal, $arg{cb}], "AnyEvent::Base::Signal"
		355	}
		356
		357	sub AnyEvent::Base::Signal::DESTROY {
		358	my ($signal, $cb) = @{$_[0]};
		359
		360	delete $SIG_CB{$signal}{$cb};
		361
		362	$SIG{$signal} = 'DEFAULT' unless keys %{ $SIG_CB{$signal} };
		363	}
		364
		365	# default implementation for ->child
		366
		367	our %PID_CB;
		368	our $CHLD_W;
		369	our $PID_IDLE;
		370	our $WNOHANG;
		371
		372	sub _child_wait {
		373	while (0 < (my $pid = waitpid -1, $WNOHANG)) {
		374	$_->() for values %{ (delete $PID_CB{$pid}) \|\| {} };
		375	}
		376
		377	undef $PID_IDLE;
		378	}
		379
		380	sub child {
		381	my (undef, %arg) = @_;
		382
		383	my $pid = uc $arg{pid}
		384	or Carp::croak "required option 'pid' is missing";
		385
		386	$PID_CB{$pid}{$arg{cb}} = $arg{cb};
		387
		388	unless ($WNOHANG) {
		389	$CHLD_W = AnyEvent->signal (signal => 'CHLD', cb => \&_child_wait);
		390	$WNOHANG = eval { require POSIX; &POSIX::WNOHANG } \|\| 1;
		391	}
		392
		393	# child could be a zombie already
		394	$PID_IDLE \|\|= AnyEvent->timer (after => 0, cb => \&_child_wait);
		395
		396	bless [$pid, $arg{cb}], "AnyEvent::Base::Child"
		397	}
		398
		399	sub AnyEvent::Base::Child::DESTROY {
		400	my ($pid, $cb) = @{$_[0]};
		401
		402	delete $PID_CB{$pid}{$cb};
		403	delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };
		404
		405	undef $CHLD_W unless keys %PID_CB;
		406	}
		407
		408	=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE
		409
		410	If you need to support another event library which isn't directly
		411	supported by AnyEvent, you can supply your own interface to it by
		412	pushing, before the first watcher gets created, the package name of
		413	the event module and the package name of the interface to use onto
		414	C<@AnyEvent::REGISTRY>. You can do that before and even without loading
		415	AnyEvent.
		416
		417	Example:
		418
		419	push @AnyEvent::REGISTRY, [urxvt => urxvt::anyevent::];
		420
		421	This tells AnyEvent to (literally) use the C<urxvt::anyevent::>
		422	package/class when it finds the C<urxvt> package/module is loaded. When
		423	AnyEvent is loaded and asked to find a suitable event model, it will
		424	first check for the presence of urxvt.
		425
		426	The class should provide implementations for all watcher types (see
		427	L<AnyEvent::Impl::Event> (source code), L<AnyEvent::Impl::Glib>
		428	(Source code) and so on for actual examples, use C<perldoc -m
		429	AnyEvent::Impl::Glib> to see the sources).
		430
		431	The above isn't fictitious, the I<rxvt-unicode> (a.k.a. urxvt)
		432	uses the above line as-is. An interface isn't included in AnyEvent
		433	because it doesn't make sense outside the embedded interpreter inside
		434	I<rxvt-unicode>, and it is updated and maintained as part of the
		435	I<rxvt-unicode> distribution.
		436
		437	I<rxvt-unicode> also cheats a bit by not providing blocking access to
		438	condition variables: code blocking while waiting for a condition will
		439	C<die>. This still works with most modules/usages, and blocking calls must
		440	not be in an interactive appliation, so it makes sense.
		441
		442	=head1 ENVIRONMENT VARIABLES
		443
		444	The following environment variables are used by this module:
		445
		446	C<PERL_ANYEVENT_VERBOSE> when set to C<2> or higher, reports which event
		447	model gets used.
119		448
120	=head1 EXAMPLE	449	=head1 EXAMPLE
121		450
122	The following program uses an io watcher to read data from stdin, a timer	451	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	452	to display a message once per second, and a condvar to exit the program

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Comparing AnyEvent/lib/AnyEvent.pm (file contents): Revision 1.6 by root, Mon Dec 19 17:03:29 2005 UTC vs. Revision 1.20 by root, Mon Dec 11 01:16:09 2006 UTC

Diff Legend

Comparing AnyEvent/lib/AnyEvent.pm (file contents):
Revision 1.6 by root, Mon Dec 19 17:03:29 2005 UTC vs.
Revision 1.20 by root, Mon Dec 11 01:16:09 2006 UTC