[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 1.16 by root, Sun Nov 5 01:08:16 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 TIMER WATCHERS
		95
		96	You can create a timer 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
		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	=head1 GLOBALS
		163
		164	=over 4
		165
		166	=item $AnyEvent::MODEL
		167
		168	Contains C<undef> until the first watcher is being created. Then it
		169	contains the event model that is being used, which is the name of the
		170	Perl class implementing the model. This class is usually one of the
		171	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>).
		173
		174	The known classes so far are:
		175
		176	AnyEvent::Impl::Coro based on Coro::Event, best choise.
		177	AnyEvent::Impl::Event based on Event, also best choice :)
		178	AnyEvent::Impl::Glib based on Glib, second-best choice.
		179	AnyEvent::Impl::Tk based on Tk, very bad choice.
		180	AnyEvent::Impl::Perl pure-perl implementation, inefficient.
		181
		182	=back
		183
		184	=head1 WHAT TO DO IN A MODULE
		185
		186	As a module author, you should "use AnyEvent" and call AnyEvent methods
		187	freely, but you should not load a specific event module or rely on it.
		188
		189	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
		191	by calling AnyEvent in your module body you force the user of your module
		192	to load the event module first.
		193
		194	=head1 WHAT TO DO IN THE MAIN PROGRAM
		195
		196	There will always be a single main program - the only place that should
		197	dictate which event model to use.
		198
		199	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.
		201
		202	If the main program relies on a specific event model (for example, in Gtk2
		203	programs you have to rely on either Glib or Glib::Event), you should load
		204	it before loading AnyEvent or any module that uses it, generally, as early
		205	as possible. The reason is that modules might create watchers when they
		206	are loaded, and AnyEvent will decide on the event model to use as soon as
		207	it creates watchers, and it might chose the wrong one unless you load the
		208	correct one yourself.
		209
		210	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
		212	generally better.
58		213
59	=cut	214	=cut
60		215
61	package AnyEvent;	216	package AnyEvent;
62		217
63	no warnings;	218	no warnings;
64	use strict 'vars';	219	use strict 'vars';
65	use Carp;	220	use Carp;
66		221
67	our $VERSION = 0.3;	222	our $VERSION = '2.0';
68	our $MODEL;	223	our $MODEL;
69		224
70	our $AUTOLOAD;	225	our $AUTOLOAD;
71	our @ISA;	226	our @ISA;
72		227
		228	our $verbose = $ENV{PERL_ANYEVENT_VERBOSE}*1;
		229
		230	our @REGISTRY;
		231
73	my @models = (	232	my @models = (
74	[Coro => Coro::Event::],	233	[Coro::Event:: => AnyEvent::Impl::Coro::],
75	[Event => Event::],	234	[Event:: => AnyEvent::Impl::Event::],
76	[Glib => Glib::],	235	[Glib:: => AnyEvent::Impl::Glib::],
77	[Tk => Tk::],	236	[Tk:: => AnyEvent::Impl::Tk::],
		237	[AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl::],
78	);	238	);
79		239
80	our %method = map +($_ => 1), qw(io timer condvar broadcast wait cancel DESTROY);	240	our %method = map +($_ => 1), qw(io timer condvar broadcast wait DESTROY);
81		241
82	sub AUTOLOAD {	242	sub AUTOLOAD {
83	$AUTOLOAD =~ s/.*://;	243	$AUTOLOAD =~ s/.*://;
84		244
85	$method{$AUTOLOAD}	245	$method{$AUTOLOAD}
86	or croak "$AUTOLOAD: not a valid method for AnyEvent objects";	246	or croak "$AUTOLOAD: not a valid method for AnyEvent objects";
87		247
88	unless ($MODEL) {	248	unless ($MODEL) {
89	# check for already loaded models	249	# check for already loaded models
90	for (@models) {	250	for (@REGISTRY, @models) {
91	my ($model, $package) = @$_;	251	my ($package, $model) = @$_;
92	if (scalar keys %{ *{"$package\::"} }) {	252	if (${"$package\::VERSION"} > 0) {
93	eval "require AnyEvent::Impl::$model";	253	if (eval "require $model") {
94	last if $MODEL;	254	$MODEL = $model;
		255	warn "AnyEvent: found model '$model', using it.\n" if $verbose > 1;
		256	last;
		257	}
95	}	258	}
96	}	259	}
97		260
98	unless ($MODEL) {	261	unless ($MODEL) {
99	# try to load a model	262	# try to load a model
100		263
101	for (@models) {	264	for (@REGISTRY, @models) {
102	my ($model, $package) = @$_;	265	my ($package, $model) = @$_;
103	eval "require AnyEvent::Impl::$model";	266	if (eval "require $model") {
104	last if $MODEL;	267	$MODEL = $model;
		268	warn "AnyEvent: autoprobed and loaded model '$model', using it.\n" if $verbose > 1;
		269	last;
		270	}
105	}	271	}
106		272
107	$MODEL	273	$MODEL
108	or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: Coro, Event, Glib or Tk.";	274	or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: Coro, Event, Glib or Tk.";
109	}	275	}
…		…
113		279
114	my $class = shift;	280	my $class = shift;
115	$class->$AUTOLOAD (@_);	281	$class->$AUTOLOAD (@_);
116	}	282	}
117		283
118	=back	284	=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE
		285
		286	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
		288	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
		290	C<@AnyEvent::REGISTRY>. You can do that before and even without loading
		291	AnyEvent.
		292
		293	Example:
		294
		295	push @AnyEvent::REGISTRY, [urxvt => urxvt::anyevent::];
		296
		297	This tells AnyEvent to (literally) use the C<urxvt::anyevent::>
		298	package/class when it finds the C<urxvt> package/module is loaded. When
		299	AnyEvent is loaded and asked to find a suitable event model, it will
		300	first check for the presence of urxvt.
		301
		302	The class should prove implementations for all watcher types (see
		303	L<AnyEvent::Impl::Event> (source code), L<AnyEvent::Impl::Glib>
		304	(Source code) and so on for actual examples, use C<perldoc -m
		305	AnyEvent::Impl::Glib> to see the sources).
		306
		307	The above 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
		309	because it doesn't make sense outside the embedded interpreter inside
		310	I<rxvt-unicode>, and it is updated and maintained as part of the
		311	I<rxvt-unicode> distribution.
		312
		313	I<rxvt-unicode> also cheats a bit by not providing blocking access to
		314	condition variables: code blocking while waiting for a condition will
		315	C<die>. This still works with most modules/usages, and blocking calls must
		316	not be in an interactive appliation, so it makes sense.
		317
		318	=head1 ENVIRONMENT VARIABLES
		319
		320	The following environment variables are used by this module:
		321
		322	C<PERL_ANYEVENT_VERBOSE> when set to C<2> or higher, reports which event
		323	model gets used.
119		324
120	=head1 EXAMPLE	325	=head1 EXAMPLE
121		326
122	The following program uses an io watcher to read data from stdin, a timer	327	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	328	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 1.16 by root, Sun Nov 5 01:08:16 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 1.16 by root, Sun Nov 5 01:08:16 2006 UTC