1 | =head1 NAME |
1 | =head1 NAME |
2 | |
2 | |
3 | AnyEvent - provide framework for multiple event loops |
3 | AnyEvent - provide framework for multiple event loops |
4 | |
4 | |
5 | Event, Coro, Glib, Tk, Perl - various supported event loops |
5 | EV, Event, Coro::EV, Coro::Event, Glib, Tk, Perl - various supported event loops |
6 | |
6 | |
7 | =head1 SYNOPSIS |
7 | =head1 SYNOPSIS |
8 | |
8 | |
9 | use AnyEvent; |
9 | use AnyEvent; |
10 | |
10 | |
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18 | |
18 | |
19 | my $w = AnyEvent->condvar; # stores wether a condition was flagged |
19 | my $w = AnyEvent->condvar; # stores wether a condition was flagged |
20 | $w->wait; # enters "main loop" till $condvar gets ->broadcast |
20 | $w->wait; # enters "main loop" till $condvar gets ->broadcast |
21 | $w->broadcast; # wake up current and all future wait's |
21 | $w->broadcast; # wake up current and all future wait's |
22 | |
22 | |
23 | =head1 WHY YOU SHOULD USE THIS MODULE |
23 | =head1 WHY YOU SHOULD USE THIS MODULE (OR NOT) |
24 | |
24 | |
25 | Glib, POE, IO::Async, Event... CPAN offers event models by the dozen |
25 | Glib, POE, IO::Async, Event... CPAN offers event models by the dozen |
26 | nowadays. So what is different about AnyEvent? |
26 | nowadays. So what is different about AnyEvent? |
27 | |
27 | |
28 | Executive Summary: AnyEvent is I<compatible>, AnyEvent is I<free of |
28 | Executive Summary: AnyEvent is I<compatible>, AnyEvent is I<free of |
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38 | programming (waiting for I/O or timer events) without subscribing to a |
38 | programming (waiting for I/O or timer events) without subscribing to a |
39 | religion, a way of living, and most importantly: without forcing your |
39 | religion, a way of living, and most importantly: without forcing your |
40 | module users into the same thing by forcing them to use the same event |
40 | module users into the same thing by forcing them to use the same event |
41 | model you use. |
41 | model you use. |
42 | |
42 | |
43 | For modules like POE or IO::Async (the latter of which is actually |
43 | For modules like POE or IO::Async (which is actually doing all I/O |
44 | named confusingly, as it does neither do I/O nor does it do anything |
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45 | asynchronously...), using them in your module is like joining a |
44 | I<synchronously>...), using them in your module is like joining a |
46 | cult: After you joined, you are dependent on them and you cannot use |
45 | cult: After you joined, you are dependent on them and you cannot use |
47 | anything else, as it is simply incompatible to everything that isn't |
46 | anything else, as it is simply incompatible to everything that isn't |
48 | itself. |
47 | itself. |
49 | |
48 | |
50 | AnyEvent + POE works fine. AnyEvent + Glib works fine. AnyEvent + Tk |
49 | AnyEvent + POE works fine. AnyEvent + Glib works fine. AnyEvent + Tk |
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59 | modules, you get an enourmous amount of code and strict rules you have |
58 | modules, you get an enourmous amount of code and strict rules you have |
60 | to follow. AnyEvent, on the other hand, is lean and to the point by only |
59 | to follow. AnyEvent, on the other hand, is lean and to the point by only |
61 | offering the functionality that is useful, in as thin as a wrapper as |
60 | offering the functionality that is useful, in as thin as a wrapper as |
62 | technically possible. |
61 | technically possible. |
63 | |
62 | |
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63 | Of course, if you want lots of policy (this can arguably be somewhat |
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64 | useful) and you want to force your users to use the one and only event |
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65 | model, you should I<not> use this module. |
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66 | |
64 | |
67 | |
65 | =head1 DESCRIPTION |
68 | =head1 DESCRIPTION |
66 | |
69 | |
67 | L<AnyEvent> provides an identical interface to multiple event loops. This |
70 | L<AnyEvent> provides an identical interface to multiple event loops. This |
68 | allows module authors to utilise an event loop without forcing module |
71 | allows module authors to utilise an event loop without forcing module |
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72 | The interface itself is vaguely similar but not identical to the Event |
75 | The interface itself is vaguely similar but not identical to the Event |
73 | module. |
76 | module. |
74 | |
77 | |
75 | On the first call of any method, the module tries to detect the currently |
78 | On the first call of any method, the module tries to detect the currently |
76 | loaded event loop by probing wether any of the following modules is |
79 | loaded event loop by probing wether any of the following modules is |
77 | loaded: L<Coro::Event>, L<Event>, L<Glib>, L<Tk>. The first one found is |
80 | loaded: L<Coro::EV>, L<Coro::Event>, L<EV>, L<Event>, L<Glib>, L<Tk>. The |
78 | used. If none is found, the module tries to load these modules in the |
81 | first one found is used. If none are found, the module tries to load these |
79 | order given. The first one that could be successfully loaded will be |
82 | modules in the order given. The first one that could be successfully |
80 | used. If still none could be found, AnyEvent will fall back to a pure-perl |
83 | loaded will be used. If still none could be found, AnyEvent will fall back |
81 | event loop, which is also not very efficient. |
84 | to a pure-perl event loop, which is also not very efficient. |
82 | |
85 | |
83 | Because AnyEvent first checks for modules that are already loaded, loading |
86 | Because AnyEvent first checks for modules that are already loaded, loading |
84 | an Event model explicitly before first using AnyEvent will likely make |
87 | an Event model explicitly before first using AnyEvent will likely make |
85 | that model the default. For example: |
88 | that model the default. For example: |
86 | |
89 | |
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115 | C<fh> the Perl I<filehandle> (not filedescriptor) to watch for |
118 | C<fh> the Perl I<filehandle> (not filedescriptor) to watch for |
116 | events. C<poll> must be a string that is either C<r> or C<w>, that creates |
119 | events. C<poll> must be a string that is either C<r> or C<w>, that creates |
117 | a watcher waiting for "r"eadable or "w"ritable events. C<cb> the callback |
120 | a watcher waiting for "r"eadable or "w"ritable events. C<cb> the callback |
118 | to invoke everytime the filehandle becomes ready. |
121 | to invoke everytime the filehandle becomes ready. |
119 | |
122 | |
120 | Only one io watcher per C<fh> and C<poll> combination is allowed (i.e. on |
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121 | a socket you can have one r + one w, not any more (limitation comes from |
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122 | Tk - if you are sure you are not using Tk this limitation is gone). |
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123 | |
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124 | Filehandles will be kept alive, so as long as the watcher exists, the |
123 | Filehandles will be kept alive, so as long as the watcher exists, the |
125 | filehandle exists, too. |
124 | filehandle exists, too. |
126 | |
125 | |
127 | Example: |
126 | Example: |
128 | |
127 | |
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176 | =item $cv->wait |
175 | =item $cv->wait |
177 | |
176 | |
178 | Wait (blocking if necessary) until the C<< ->broadcast >> method has been |
177 | Wait (blocking if necessary) until the C<< ->broadcast >> method has been |
179 | called on c<$cv>, while servicing other watchers normally. |
178 | called on c<$cv>, while servicing other watchers normally. |
180 | |
179 | |
181 | Not all event models support a blocking wait - some die in that case, so |
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182 | if you are using this from a module, never require a blocking wait, but |
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183 | let the caller decide wether the call will block or not (for example, |
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184 | by coupling condition variables with some kind of request results and |
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185 | supporting callbacks so the caller knows that getting the result will not |
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186 | block, while still suppporting blockign waits if the caller so desires). |
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187 | |
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188 | You can only wait once on a condition - additional calls will return |
180 | You can only wait once on a condition - additional calls will return |
189 | immediately. |
181 | immediately. |
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182 | |
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183 | Not all event models support a blocking wait - some die in that case |
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184 | (programs might want to do that so they stay interactive), so I<if you |
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185 | are using this from a module, never require a blocking wait>, but let the |
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186 | caller decide wether the call will block or not (for example, by coupling |
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187 | condition variables with some kind of request results and supporting |
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188 | callbacks so the caller knows that getting the result will not block, |
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189 | while still suppporting blocking waits if the caller so desires). |
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190 | |
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191 | Another reason I<never> to C<< ->wait >> in a module is that you cannot |
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192 | sensibly have two C<< ->wait >>'s in parallel, as that would require |
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193 | multiple interpreters or coroutines/threads, none of which C<AnyEvent> |
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194 | can supply (the coroutine-aware backends C<Coro::EV> and C<Coro::Event> |
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195 | explicitly support concurrent C<< ->wait >>'s from different coroutines, |
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196 | however). |
190 | |
197 | |
191 | =item $cv->broadcast |
198 | =item $cv->broadcast |
192 | |
199 | |
193 | Flag the condition as ready - a running C<< ->wait >> and all further |
200 | Flag the condition as ready - a running C<< ->wait >> and all further |
194 | calls to C<wait> will return after this method has been called. If nobody |
201 | calls to C<wait> will return after this method has been called. If nobody |
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246 | AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode>). |
253 | AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode>). |
247 | |
254 | |
248 | The known classes so far are: |
255 | The known classes so far are: |
249 | |
256 | |
250 | AnyEvent::Impl::CoroEV based on Coro::EV, best choice. |
257 | AnyEvent::Impl::CoroEV based on Coro::EV, best choice. |
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258 | AnyEvent::Impl::CoroEvent based on Coro::Event, second best choice. |
251 | AnyEvent::Impl::EV based on EV (an interface to libev, also best choice). |
259 | AnyEvent::Impl::EV based on EV (an interface to libev, also best choice). |
252 | AnyEvent::Impl::CoroEvent based on Coro::Event, second best choice. |
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253 | AnyEvent::Impl::Event based on Event, also second best choice :) |
260 | AnyEvent::Impl::Event based on Event, also second best choice :) |
254 | AnyEvent::Impl::Glib based on Glib, second-best choice. |
261 | AnyEvent::Impl::Glib based on Glib, third-best choice. |
255 | AnyEvent::Impl::Tk based on Tk, very bad choice. |
262 | AnyEvent::Impl::Tk based on Tk, very bad choice. |
256 | AnyEvent::Impl::Perl pure-perl implementation, inefficient. |
263 | AnyEvent::Impl::Perl pure-perl implementation, inefficient but portable. |
257 | |
264 | |
258 | =item AnyEvent::detect |
265 | =item AnyEvent::detect |
259 | |
266 | |
260 | Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model if |
267 | Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model if |
261 | necessary. You should only call this function right before you would have |
268 | necessary. You should only call this function right before you would have |
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300 | no warnings; |
307 | no warnings; |
301 | use strict; |
308 | use strict; |
302 | |
309 | |
303 | use Carp; |
310 | use Carp; |
304 | |
311 | |
305 | our $VERSION = '3.0'; |
312 | our $VERSION = '3.1'; |
306 | our $MODEL; |
313 | our $MODEL; |
307 | |
314 | |
308 | our $AUTOLOAD; |
315 | our $AUTOLOAD; |
309 | our @ISA; |
316 | our @ISA; |
310 | |
317 | |
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312 | |
319 | |
313 | our @REGISTRY; |
320 | our @REGISTRY; |
314 | |
321 | |
315 | my @models = ( |
322 | my @models = ( |
316 | [Coro::EV:: => AnyEvent::Impl::CoroEV::], |
323 | [Coro::EV:: => AnyEvent::Impl::CoroEV::], |
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324 | [Coro::Event:: => AnyEvent::Impl::CoroEvent::], |
317 | [EV:: => AnyEvent::Impl::EV::], |
325 | [EV:: => AnyEvent::Impl::EV::], |
318 | [Coro::Event:: => AnyEvent::Impl::CoroEvent::], |
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319 | [Event:: => AnyEvent::Impl::Event::], |
326 | [Event:: => AnyEvent::Impl::Event::], |
320 | [Glib:: => AnyEvent::Impl::Glib::], |
327 | [Glib:: => AnyEvent::Impl::Glib::], |
321 | [Tk:: => AnyEvent::Impl::Tk::], |
328 | [Tk:: => AnyEvent::Impl::Tk::], |
322 | [AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl::], |
329 | [AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl::], |
323 | ); |
330 | ); |
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631 | |
638 | |
632 | 1. Blocking: |
639 | 1. Blocking: |
633 | |
640 | |
634 | my $data = $fcp->client_get ($url); |
641 | my $data = $fcp->client_get ($url); |
635 | |
642 | |
636 | 2. Blocking, but parallelizing: |
643 | 2. Blocking, but running in parallel: |
637 | |
644 | |
638 | my @datas = map $_->result, |
645 | my @datas = map $_->result, |
639 | map $fcp->txn_client_get ($_), |
646 | map $fcp->txn_client_get ($_), |
640 | @urls; |
647 | @urls; |
641 | |
648 | |
642 | Both blocking examples work without the module user having to know |
649 | Both blocking examples work without the module user having to know |
643 | anything about events. |
650 | anything about events. |
644 | |
651 | |
645 | 3a. Event-based in a main program, using any support Event module: |
652 | 3a. Event-based in a main program, using any supported event module: |
646 | |
653 | |
647 | use Event; |
654 | use EV; |
648 | |
655 | |
649 | $fcp->txn_client_get ($url)->cb (sub { |
656 | $fcp->txn_client_get ($url)->cb (sub { |
650 | my $txn = shift; |
657 | my $txn = shift; |
651 | my $data = $txn->result; |
658 | my $data = $txn->result; |
652 | ... |
659 | ... |
653 | }); |
660 | }); |
654 | |
661 | |
655 | Event::loop; |
662 | EV::loop; |
656 | |
663 | |
657 | 3b. The module user could use AnyEvent, too: |
664 | 3b. The module user could use AnyEvent, too: |
658 | |
665 | |
659 | use AnyEvent; |
666 | use AnyEvent; |
660 | |
667 | |
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667 | |
674 | |
668 | $quit->wait; |
675 | $quit->wait; |
669 | |
676 | |
670 | =head1 SEE ALSO |
677 | =head1 SEE ALSO |
671 | |
678 | |
672 | Event modules: L<Coro::Event>, L<Coro>, L<Event>, L<Glib::Event>, L<Glib>. |
679 | Event modules: L<Coro::EV>, L<EV>, L<EV::Glib>, L<Glib::EV>, |
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680 | L<Coro::Event>, L<Event>, L<Glib::Event>, L<Glib>, L<Coro>, L<Tk>. |
673 | |
681 | |
674 | Implementations: L<AnyEvent::Impl::Coro>, L<AnyEvent::Impl::Event>, L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>. |
682 | Implementations: L<AnyEvent::Impl::CoroEV>, L<AnyEvent::Impl::EV>, |
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683 | L<AnyEvent::Impl::CoroEvent>, L<AnyEvent::Impl::Event>, |
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684 | L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>. |
675 | |
685 | |
676 | Nontrivial usage example: L<Net::FCP>. |
686 | Nontrivial usage examples: L<Net::FCP>, L<Net::XMPP2>. |
677 | |
687 | |
678 | =head1 |
688 | =head1 |
679 | |
689 | |
680 | =cut |
690 | =cut |
681 | |
691 | |