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 | EV, Event, Coro::EV, Coro::Event, Glib, Tk, Perl, Event::Lib, Qt, POE - various supported event loops |
5 | EV, Event, Glib, Tk, Perl, Event::Lib, Qt, POE - 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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15 | my $w = AnyEvent->timer (after => $seconds, cb => sub { |
15 | my $w = AnyEvent->timer (after => $seconds, cb => sub { |
16 | ... |
16 | ... |
17 | }); |
17 | }); |
18 | |
18 | |
19 | my $w = AnyEvent->condvar; # stores whether a condition was flagged |
19 | my $w = AnyEvent->condvar; # stores whether a condition was flagged |
20 | $w->wait; # enters "main loop" till $condvar gets ->broadcast |
20 | $w->wait; # enters "main loop" till $condvar gets ->send |
21 | $w->broadcast; # wake up current and all future wait's |
21 | $w->send; # wake up current and all future wait's |
22 | |
22 | |
23 | =head1 WHY YOU SHOULD USE THIS MODULE (OR NOT) |
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? |
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66 | |
66 | |
67 | Of course, if you want lots of policy (this can arguably be somewhat |
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 |
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. |
69 | model, you should I<not> use this module. |
70 | |
70 | |
71 | #TODO# |
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72 | |
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73 | Net::IRC3 |
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74 | AnyEvent::HTTPD |
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75 | AnyEvent::DNS |
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76 | IO::AnyEvent |
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77 | Net::FPing |
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78 | Net::XMPP2 |
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79 | Coro |
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80 | |
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81 | AnyEvent::IRC |
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82 | AnyEvent::HTTPD |
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83 | AnyEvent::DNS |
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84 | AnyEvent::Handle |
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85 | AnyEvent::Socket |
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86 | AnyEvent::FPing |
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87 | AnyEvent::XMPP |
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88 | AnyEvent::SNMP |
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89 | Coro |
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90 | |
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91 | =head1 DESCRIPTION |
71 | =head1 DESCRIPTION |
92 | |
72 | |
93 | L<AnyEvent> provides an identical interface to multiple event loops. This |
73 | L<AnyEvent> provides an identical interface to multiple event loops. This |
94 | allows module authors to utilise an event loop without forcing module |
74 | allows module authors to utilise an event loop without forcing module |
95 | users to use the same event loop (as only a single event loop can coexist |
75 | users to use the same event loop (as only a single event loop can coexist |
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98 | The interface itself is vaguely similar, but not identical to the L<Event> |
78 | The interface itself is vaguely similar, but not identical to the L<Event> |
99 | module. |
79 | module. |
100 | |
80 | |
101 | During the first call of any watcher-creation method, the module tries |
81 | During the first call of any watcher-creation method, the module tries |
102 | to detect the currently loaded event loop by probing whether one of the |
82 | to detect the currently loaded event loop by probing whether one of the |
103 | following modules is already loaded: L<Coro::EV>, L<Coro::Event>, L<EV>, |
83 | following modules is already loaded: L<EV>, |
104 | L<Event>, L<Glib>, L<AnyEvent::Impl::Perl>, L<Tk>, L<Event::Lib>, L<Qt>, |
84 | L<Event>, L<Glib>, L<AnyEvent::Impl::Perl>, L<Tk>, L<Event::Lib>, L<Qt>, |
105 | L<POE>. The first one found is used. If none are found, the module tries |
85 | L<POE>. The first one found is used. If none are found, the module tries |
106 | to load these modules (excluding Tk, Event::Lib, Qt and POE as the pure perl |
86 | to load these modules (excluding Tk, Event::Lib, Qt and POE as the pure perl |
107 | adaptor should always succeed) in the order given. The first one that can |
87 | adaptor should always succeed) in the order given. The first one that can |
108 | be successfully loaded will be used. If, after this, still none could be |
88 | be successfully loaded will be used. If, after this, still none could be |
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308 | my $w = AnyEvent->child ( |
288 | my $w = AnyEvent->child ( |
309 | pid => $pid, |
289 | pid => $pid, |
310 | cb => sub { |
290 | cb => sub { |
311 | my ($pid, $status) = @_; |
291 | my ($pid, $status) = @_; |
312 | warn "pid $pid exited with status $status"; |
292 | warn "pid $pid exited with status $status"; |
313 | $done->broadcast; |
293 | $done->send; |
314 | }, |
294 | }, |
315 | ); |
295 | ); |
316 | |
296 | |
317 | # do something else, then wait for process exit |
297 | # do something else, then wait for process exit |
318 | $done->wait; |
298 | $done->wait; |
319 | |
299 | |
320 | =head2 CONDITION VARIABLES |
300 | =head2 CONDITION VARIABLES |
321 | |
301 | |
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302 | If you are familiar with some event loops you will know that all of them |
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303 | require you to run some blocking "loop", "run" or similar function that |
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304 | will actively watch for new events and call your callbacks. |
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305 | |
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306 | AnyEvent is different, it expects somebody else to run the event loop and |
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307 | will only block when necessary (usually when told by the user). |
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308 | |
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309 | The instrument to do that is called a "condition variable", so called |
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310 | because they represent a condition that must become true. |
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311 | |
322 | Condition variables can be created by calling the C<< AnyEvent->condvar >> |
312 | Condition variables can be created by calling the C<< AnyEvent->condvar |
323 | method without any arguments. |
313 | >> method, usually without arguments. The only argument pair allowed is |
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314 | C<cb>, which specifies a callback to be called when the condition variable |
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315 | becomes true. |
324 | |
316 | |
325 | A condition variable waits for a condition - precisely that the C<< |
317 | After creation, the conditon variable is "false" until it becomes "true" |
326 | ->broadcast >> method has been called. |
318 | by calling the C<send> method. |
327 | |
319 | |
328 | They are very useful to signal that a condition has been fulfilled, for |
320 | Condition variables are similar to callbacks, except that you can |
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321 | optionally wait for them. They can also be called merge points - points |
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322 | in time where multiple outstandign events have been processed. And yet |
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323 | another way to call them is transations - each condition variable can be |
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324 | used to represent a transaction, which finishes at some point and delivers |
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325 | a result. |
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326 | |
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327 | Condition variables are very useful to signal that something has finished, |
329 | example, if you write a module that does asynchronous http requests, |
328 | for example, if you write a module that does asynchronous http requests, |
330 | then a condition variable would be the ideal candidate to signal the |
329 | then a condition variable would be the ideal candidate to signal the |
331 | availability of results. |
330 | availability of results. The user can either act when the callback is |
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331 | called or can synchronously C<< ->wait >> for the results. |
332 | |
332 | |
333 | You can also use condition variables to block your main program until |
333 | You can also use them to simulate traditional event loops - for example, |
334 | an event occurs - for example, you could C<< ->wait >> in your main |
334 | you can block your main program until an event occurs - for example, you |
335 | program until the user clicks the Quit button in your app, which would C<< |
335 | could C<< ->wait >> in your main program until the user clicks the Quit |
336 | ->broadcast >> the "quit" event. |
336 | button of your app, which would C<< ->send >> the "quit" event. |
337 | |
337 | |
338 | Note that condition variables recurse into the event loop - if you have |
338 | Note that condition variables recurse into the event loop - if you have |
339 | two pirces of code that call C<< ->wait >> in a round-robbin fashion, you |
339 | two pieces of code that call C<< ->wait >> in a round-robbin fashion, you |
340 | lose. Therefore, condition variables are good to export to your caller, but |
340 | lose. Therefore, condition variables are good to export to your caller, but |
341 | you should avoid making a blocking wait yourself, at least in callbacks, |
341 | you should avoid making a blocking wait yourself, at least in callbacks, |
342 | as this asks for trouble. |
342 | as this asks for trouble. |
343 | |
343 | |
344 | This object has two methods: |
344 | Condition variables are represented by hash refs in perl, and the keys |
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345 | used by AnyEvent itself are all named C<_ae_XXX> to make subclassing |
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346 | easy (it is often useful to build your own transaction class on top of |
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347 | AnyEvent). To subclass, use C<AnyEvent::CondVar> as base class and call |
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348 | it's C<new> method in your own C<new> method. |
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349 | |
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350 | There are two "sides" to a condition variable - the "producer side" which |
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351 | eventually calls C<< -> send >>, and the "consumer side", which waits |
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352 | for the send to occur. |
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353 | |
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354 | Example: |
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355 | |
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356 | # wait till the result is ready |
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357 | my $result_ready = AnyEvent->condvar; |
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358 | |
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359 | # do something such as adding a timer |
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360 | # or socket watcher the calls $result_ready->send |
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361 | # when the "result" is ready. |
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362 | # in this case, we simply use a timer: |
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363 | my $w = AnyEvent->timer ( |
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364 | after => 1, |
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365 | cb => sub { $result_ready->send }, |
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366 | ); |
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367 | |
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368 | # this "blocks" (while handling events) till the callback |
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369 | # calls send |
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370 | $result_ready->wait; |
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371 | |
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372 | =head3 METHODS FOR PRODUCERS |
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373 | |
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374 | These methods should only be used by the producing side, i.e. the |
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375 | code/module that eventually sends the signal. Note that it is also |
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376 | the producer side which creates the condvar in most cases, but it isn't |
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377 | uncommon for the consumer to create it as well. |
345 | |
378 | |
346 | =over 4 |
379 | =over 4 |
347 | |
380 | |
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381 | =item $cv->send (...) |
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382 | |
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383 | Flag the condition as ready - a running C<< ->wait >> and all further |
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384 | calls to C<wait> will (eventually) return after this method has been |
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385 | called. If nobody is waiting the send will be remembered. |
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386 | |
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387 | If a callback has been set on the condition variable, it is called |
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388 | immediately from within send. |
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389 | |
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390 | Any arguments passed to the C<send> call will be returned by all |
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391 | future C<< ->wait >> calls. |
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392 | |
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393 | =item $cv->croak ($error) |
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394 | |
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395 | Similar to send, but causes all call's wait C<< ->wait >> to invoke |
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396 | C<Carp::croak> with the given error message/object/scalar. |
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397 | |
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398 | This can be used to signal any errors to the condition variable |
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399 | user/consumer. |
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400 | |
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401 | =item $cv->begin ([group callback]) |
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402 | |
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403 | =item $cv->end |
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404 | |
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405 | These two methods can be used to combine many transactions/events into |
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406 | one. For example, a function that pings many hosts in parallel might want |
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407 | to use a condition variable for the whole process. |
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408 | |
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409 | Every call to C<< ->begin >> will increment a counter, and every call to |
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410 | C<< ->end >> will decrement it. If the counter reaches C<0> in C<< ->end |
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411 | >>, the (last) callback passed to C<begin> will be executed. That callback |
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412 | is I<supposed> to call C<< ->send >>, but that is not required. If no |
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413 | callback was set, C<send> will be called without any arguments. |
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414 | |
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415 | Let's clarify this with the ping example: |
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416 | |
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417 | my $cv = AnyEvent->condvar; |
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418 | |
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419 | my %result; |
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420 | $cv->begin (sub { $cv->send (\%result) }); |
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421 | |
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422 | for my $host (@list_of_hosts) { |
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423 | $cv->begin; |
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424 | ping_host_then_call_callback $host, sub { |
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425 | $result{$host} = ...; |
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426 | $cv->end; |
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427 | }; |
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428 | } |
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429 | |
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430 | $cv->end; |
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431 | |
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432 | This code fragment supposedly pings a number of hosts and calls |
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433 | C<send> after results for all then have have been gathered - in any |
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434 | order. To achieve this, the code issues a call to C<begin> when it starts |
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435 | each ping request and calls C<end> when it has received some result for |
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436 | it. Since C<begin> and C<end> only maintain a counter, the order in which |
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437 | results arrive is not relevant. |
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438 | |
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439 | There is an additional bracketing call to C<begin> and C<end> outside the |
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440 | loop, which serves two important purposes: first, it sets the callback |
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441 | to be called once the counter reaches C<0>, and second, it ensures that |
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442 | C<send> is called even when C<no> hosts are being pinged (the loop |
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443 | doesn't execute once). |
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444 | |
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445 | This is the general pattern when you "fan out" into multiple subrequests: |
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446 | use an outer C<begin>/C<end> pair to set the callback and ensure C<end> |
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447 | is called at least once, and then, for each subrequest you start, call |
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448 | C<begin> and for eahc subrequest you finish, call C<end>. |
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449 | |
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450 | =back |
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451 | |
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452 | =head3 METHODS FOR CONSUMERS |
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453 | |
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454 | These methods should only be used by the consuming side, i.e. the |
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455 | code awaits the condition. |
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456 | |
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457 | =over 4 |
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458 | |
348 | =item $cv->wait |
459 | =item $cv->wait |
349 | |
460 | |
350 | Wait (blocking if necessary) until the C<< ->broadcast >> method has been |
461 | Wait (blocking if necessary) until the C<< ->send >> or C<< ->croak |
351 | called on c<$cv>, while servicing other watchers normally. |
462 | >> methods have been called on c<$cv>, while servicing other watchers |
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463 | normally. |
352 | |
464 | |
353 | You can only wait once on a condition - additional calls will return |
465 | You can only wait once on a condition - additional calls are valid but |
354 | immediately. |
466 | will return immediately. |
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467 | |
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468 | If an error condition has been set by calling C<< ->croak >>, then this |
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469 | function will call C<croak>. |
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470 | |
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471 | In list context, all parameters passed to C<send> will be returned, |
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472 | in scalar context only the first one will be returned. |
355 | |
473 | |
356 | Not all event models support a blocking wait - some die in that case |
474 | Not all event models support a blocking wait - some die in that case |
357 | (programs might want to do that to stay interactive), so I<if you are |
475 | (programs might want to do that to stay interactive), so I<if you are |
358 | using this from a module, never require a blocking wait>, but let the |
476 | using this from a module, never require a blocking wait>, but let the |
359 | caller decide whether the call will block or not (for example, by coupling |
477 | caller decide whether the call will block or not (for example, by coupling |
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362 | while still suppporting blocking waits if the caller so desires). |
480 | while still suppporting blocking waits if the caller so desires). |
363 | |
481 | |
364 | Another reason I<never> to C<< ->wait >> in a module is that you cannot |
482 | Another reason I<never> to C<< ->wait >> in a module is that you cannot |
365 | sensibly have two C<< ->wait >>'s in parallel, as that would require |
483 | sensibly have two C<< ->wait >>'s in parallel, as that would require |
366 | multiple interpreters or coroutines/threads, none of which C<AnyEvent> |
484 | multiple interpreters or coroutines/threads, none of which C<AnyEvent> |
367 | can supply (the coroutine-aware backends L<AnyEvent::Impl::CoroEV> and |
485 | can supply. |
368 | L<AnyEvent::Impl::CoroEvent> explicitly support concurrent C<< ->wait >>'s |
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369 | from different coroutines, however). |
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370 | |
486 | |
371 | =item $cv->broadcast |
487 | The L<Coro> module, however, I<can> and I<does> supply coroutines and, in |
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488 | fact, L<Coro::AnyEvent> replaces AnyEvent's condvars by coroutine-safe |
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489 | versions and also integrates coroutines into AnyEvent, making blocking |
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490 | C<< ->wait >> calls perfectly safe as long as they are done from another |
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491 | coroutine (one that doesn't run the event loop). |
372 | |
492 | |
373 | Flag the condition as ready - a running C<< ->wait >> and all further |
493 | You can ensure that C<< -wait >> never blocks by setting a callback and |
374 | calls to C<wait> will (eventually) return after this method has been |
494 | only calling C<< ->wait >> from within that callback (or at a later |
375 | called. If nobody is waiting the broadcast will be remembered.. |
495 | time). This will work even when the event loop does not support blocking |
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496 | waits otherwise. |
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497 | |
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498 | =item $bool = $cv->ready |
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499 | |
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500 | Returns true when the condition is "true", i.e. whether C<send> or |
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501 | C<croak> have been called. |
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502 | |
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503 | =item $cb = $cv->cb ([new callback]) |
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504 | |
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505 | This is a mutator function that returns the callback set and optionally |
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506 | replaces it before doing so. |
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507 | |
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508 | The callback will be called when the condition becomes "true", i.e. when |
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509 | C<send> or C<croak> are called. Calling C<wait> inside the callback |
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510 | or at any later time is guaranteed not to block. |
376 | |
511 | |
377 | =back |
512 | =back |
378 | |
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379 | Example: |
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380 | |
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381 | # wait till the result is ready |
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382 | my $result_ready = AnyEvent->condvar; |
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383 | |
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384 | # do something such as adding a timer |
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385 | # or socket watcher the calls $result_ready->broadcast |
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386 | # when the "result" is ready. |
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387 | # in this case, we simply use a timer: |
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388 | my $w = AnyEvent->timer ( |
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389 | after => 1, |
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390 | cb => sub { $result_ready->broadcast }, |
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391 | ); |
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392 | |
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393 | # this "blocks" (while handling events) till the watcher |
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394 | # calls broadcast |
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395 | $result_ready->wait; |
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396 | |
513 | |
397 | =head1 GLOBAL VARIABLES AND FUNCTIONS |
514 | =head1 GLOBAL VARIABLES AND FUNCTIONS |
398 | |
515 | |
399 | =over 4 |
516 | =over 4 |
400 | |
517 | |
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406 | C<AnyEvent::Impl:xxx> modules, but can be any other class in the case |
523 | C<AnyEvent::Impl:xxx> modules, but can be any other class in the case |
407 | AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode>). |
524 | AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode>). |
408 | |
525 | |
409 | The known classes so far are: |
526 | The known classes so far are: |
410 | |
527 | |
411 | AnyEvent::Impl::CoroEV based on Coro::EV, best choice. |
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412 | AnyEvent::Impl::CoroEvent based on Coro::Event, second best choice. |
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413 | AnyEvent::Impl::EV based on EV (an interface to libev, best choice). |
528 | AnyEvent::Impl::EV based on EV (an interface to libev, best choice). |
414 | AnyEvent::Impl::Event based on Event, second best choice. |
529 | AnyEvent::Impl::Event based on Event, second best choice. |
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530 | AnyEvent::Impl::Perl pure-perl implementation, fast and portable. |
415 | AnyEvent::Impl::Glib based on Glib, third-best choice. |
531 | AnyEvent::Impl::Glib based on Glib, third-best choice. |
416 | AnyEvent::Impl::Perl pure-perl implementation, inefficient but portable. |
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417 | AnyEvent::Impl::Tk based on Tk, very bad choice. |
532 | AnyEvent::Impl::Tk based on Tk, very bad choice. |
418 | AnyEvent::Impl::Qt based on Qt, cannot be autoprobed (see its docs). |
533 | AnyEvent::Impl::Qt based on Qt, cannot be autoprobed (see its docs). |
419 | AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse. |
534 | AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse. |
420 | AnyEvent::Impl::POE based on POE, not generic enough for full support. |
535 | AnyEvent::Impl::POE based on POE, not generic enough for full support. |
421 | |
536 | |
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434 | Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model |
549 | Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model |
435 | if necessary. You should only call this function right before you would |
550 | if necessary. You should only call this function right before you would |
436 | have created an AnyEvent watcher anyway, that is, as late as possible at |
551 | have created an AnyEvent watcher anyway, that is, as late as possible at |
437 | runtime. |
552 | runtime. |
438 | |
553 | |
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554 | =item $guard = AnyEvent::post_detect { BLOCK } |
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555 | |
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556 | Arranges for the code block to be executed as soon as the event model is |
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557 | autodetected (or immediately if this has already happened). |
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558 | |
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559 | If called in scalar or list context, then it creates and returns an object |
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560 | that automatically removes the callback again when it is destroyed. |
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561 | |
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562 | =item @AnyEvent::post_detect |
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563 | |
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564 | If there are any code references in this array (you can C<push> to it |
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565 | before or after loading AnyEvent), then they will called directly after |
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566 | the event loop has been chosen. |
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567 | |
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568 | You should check C<$AnyEvent::MODEL> before adding to this array, though: |
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569 | if it contains a true value then the event loop has already been detected, |
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570 | and the array will be ignored. |
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571 | |
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572 | Best use C<AnyEvent::post_detect { BLOCK }> instead. |
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573 | |
439 | =back |
574 | =back |
440 | |
575 | |
441 | =head1 WHAT TO DO IN A MODULE |
576 | =head1 WHAT TO DO IN A MODULE |
442 | |
577 | |
443 | As a module author, you should C<use AnyEvent> and call AnyEvent methods |
578 | As a module author, you should C<use AnyEvent> and call AnyEvent methods |
… | |
… | |
447 | decide which event module to use as soon as the first method is called, so |
582 | decide which event module to use as soon as the first method is called, so |
448 | by calling AnyEvent in your module body you force the user of your module |
583 | by calling AnyEvent in your module body you force the user of your module |
449 | to load the event module first. |
584 | to load the event module first. |
450 | |
585 | |
451 | Never call C<< ->wait >> on a condition variable unless you I<know> that |
586 | Never call C<< ->wait >> on a condition variable unless you I<know> that |
452 | the C<< ->broadcast >> method has been called on it already. This is |
587 | the C<< ->send >> method has been called on it already. This is |
453 | because it will stall the whole program, and the whole point of using |
588 | because it will stall the whole program, and the whole point of using |
454 | events is to stay interactive. |
589 | events is to stay interactive. |
455 | |
590 | |
456 | It is fine, however, to call C<< ->wait >> when the user of your module |
591 | It is fine, however, to call C<< ->wait >> when the user of your module |
457 | requests it (i.e. if you create a http request object ad have a method |
592 | requests it (i.e. if you create a http request object ad have a method |
… | |
… | |
477 | |
612 | |
478 | You can chose to use a rather inefficient pure-perl implementation by |
613 | You can chose to use a rather inefficient pure-perl implementation by |
479 | loading the C<AnyEvent::Impl::Perl> module, which gives you similar |
614 | loading the C<AnyEvent::Impl::Perl> module, which gives you similar |
480 | behaviour everywhere, but letting AnyEvent chose is generally better. |
615 | behaviour everywhere, but letting AnyEvent chose is generally better. |
481 | |
616 | |
|
|
617 | =head1 OTHER MODULES |
|
|
618 | |
|
|
619 | The following is a non-exhaustive list of additional modules that use |
|
|
620 | AnyEvent and can therefore be mixed easily with other AnyEvent modules |
|
|
621 | in the same program. Some of the modules come with AnyEvent, some are |
|
|
622 | available via CPAN. |
|
|
623 | |
|
|
624 | =over 4 |
|
|
625 | |
|
|
626 | =item L<AnyEvent::Util> |
|
|
627 | |
|
|
628 | Contains various utility functions that replace often-used but blocking |
|
|
629 | functions such as C<inet_aton> by event-/callback-based versions. |
|
|
630 | |
|
|
631 | =item L<AnyEvent::Handle> |
|
|
632 | |
|
|
633 | Provide read and write buffers and manages watchers for reads and writes. |
|
|
634 | |
|
|
635 | =item L<AnyEvent::Socket> |
|
|
636 | |
|
|
637 | Provides a means to do non-blocking connects, accepts etc. |
|
|
638 | |
|
|
639 | =item L<AnyEvent::HTTPD> |
|
|
640 | |
|
|
641 | Provides a simple web application server framework. |
|
|
642 | |
|
|
643 | =item L<AnyEvent::DNS> |
|
|
644 | |
|
|
645 | Provides asynchronous DNS resolver capabilities, beyond what |
|
|
646 | L<AnyEvent::Util> offers. |
|
|
647 | |
|
|
648 | =item L<AnyEvent::FastPing> |
|
|
649 | |
|
|
650 | The fastest ping in the west. |
|
|
651 | |
|
|
652 | =item L<Net::IRC3> |
|
|
653 | |
|
|
654 | AnyEvent based IRC client module family. |
|
|
655 | |
|
|
656 | =item L<Net::XMPP2> |
|
|
657 | |
|
|
658 | AnyEvent based XMPP (Jabber protocol) module family. |
|
|
659 | |
|
|
660 | =item L<Net::FCP> |
|
|
661 | |
|
|
662 | AnyEvent-based implementation of the Freenet Client Protocol, birthplace |
|
|
663 | of AnyEvent. |
|
|
664 | |
|
|
665 | =item L<Event::ExecFlow> |
|
|
666 | |
|
|
667 | High level API for event-based execution flow control. |
|
|
668 | |
|
|
669 | =item L<Coro> |
|
|
670 | |
|
|
671 | Has special support for AnyEvent via L<Coro::AnyEvent>. |
|
|
672 | |
|
|
673 | =item L<IO::Lambda> |
|
|
674 | |
|
|
675 | The lambda approach to I/O - don't ask, look there. Can use AnyEvent. |
|
|
676 | |
|
|
677 | =item L<IO::AIO> |
|
|
678 | |
|
|
679 | Truly asynchronous I/O, should be in the toolbox of every event |
|
|
680 | programmer. Can be trivially made to use AnyEvent. |
|
|
681 | |
|
|
682 | =item L<BDB> |
|
|
683 | |
|
|
684 | Truly asynchronous Berkeley DB access. Can be trivially made to use |
|
|
685 | AnyEvent. |
|
|
686 | |
|
|
687 | =back |
|
|
688 | |
482 | =cut |
689 | =cut |
483 | |
690 | |
484 | package AnyEvent; |
691 | package AnyEvent; |
485 | |
692 | |
486 | no warnings; |
693 | no warnings; |
487 | use strict; |
694 | use strict; |
488 | |
695 | |
489 | use Carp; |
696 | use Carp; |
490 | |
697 | |
491 | our $VERSION = '3.3'; |
698 | our $VERSION = '3.4'; |
492 | our $MODEL; |
699 | our $MODEL; |
493 | |
700 | |
494 | our $AUTOLOAD; |
701 | our $AUTOLOAD; |
495 | our @ISA; |
702 | our @ISA; |
496 | |
703 | |
497 | our $verbose = $ENV{PERL_ANYEVENT_VERBOSE}*1; |
704 | our $verbose = $ENV{PERL_ANYEVENT_VERBOSE}*1; |
498 | |
705 | |
499 | our @REGISTRY; |
706 | our @REGISTRY; |
500 | |
707 | |
501 | my @models = ( |
708 | my @models = ( |
502 | [Coro::EV:: => AnyEvent::Impl::CoroEV::], |
|
|
503 | [Coro::Event:: => AnyEvent::Impl::CoroEvent::], |
|
|
504 | [EV:: => AnyEvent::Impl::EV::], |
709 | [EV:: => AnyEvent::Impl::EV::], |
505 | [Event:: => AnyEvent::Impl::Event::], |
710 | [Event:: => AnyEvent::Impl::Event::], |
506 | [Glib:: => AnyEvent::Impl::Glib::], |
|
|
507 | [Tk:: => AnyEvent::Impl::Tk::], |
711 | [Tk:: => AnyEvent::Impl::Tk::], |
508 | [Wx:: => AnyEvent::Impl::POE::], |
712 | [Wx:: => AnyEvent::Impl::POE::], |
509 | [Prima:: => AnyEvent::Impl::POE::], |
713 | [Prima:: => AnyEvent::Impl::POE::], |
510 | [AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl::], |
714 | [AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl::], |
511 | # everything below here will not be autoprobed as the pureperl backend should work everywhere |
715 | # everything below here will not be autoprobed as the pureperl backend should work everywhere |
|
|
716 | [Glib:: => AnyEvent::Impl::Glib::], |
512 | [Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy |
717 | [Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy |
513 | [Qt:: => AnyEvent::Impl::Qt::], # requires special main program |
718 | [Qt:: => AnyEvent::Impl::Qt::], # requires special main program |
514 | [POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza |
719 | [POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza |
515 | ); |
720 | ); |
516 | |
721 | |
517 | our %method = map +($_ => 1), qw(io timer signal child condvar broadcast wait one_event DESTROY); |
722 | our %method = map +($_ => 1), qw(io timer signal child condvar one_event DESTROY); |
|
|
723 | |
|
|
724 | our @post_detect; |
|
|
725 | |
|
|
726 | sub post_detect(&) { |
|
|
727 | my ($cb) = @_; |
|
|
728 | |
|
|
729 | if ($MODEL) { |
|
|
730 | $cb->(); |
|
|
731 | |
|
|
732 | 1 |
|
|
733 | } else { |
|
|
734 | push @post_detect, $cb; |
|
|
735 | |
|
|
736 | defined wantarray |
|
|
737 | ? bless \$cb, "AnyEvent::Util::Guard" |
|
|
738 | : () |
|
|
739 | } |
|
|
740 | } |
|
|
741 | |
|
|
742 | sub AnyEvent::Util::Guard::DESTROY { |
|
|
743 | @post_detect = grep $_ != ${$_[0]}, @post_detect; |
|
|
744 | } |
518 | |
745 | |
519 | sub detect() { |
746 | sub detect() { |
520 | unless ($MODEL) { |
747 | unless ($MODEL) { |
521 | no strict 'refs'; |
748 | no strict 'refs'; |
522 | |
749 | |
… | |
… | |
556 | last; |
783 | last; |
557 | } |
784 | } |
558 | } |
785 | } |
559 | |
786 | |
560 | $MODEL |
787 | $MODEL |
561 | 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."; |
788 | or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV, Event or Glib."; |
562 | } |
789 | } |
563 | } |
790 | } |
564 | |
791 | |
565 | unshift @ISA, $MODEL; |
792 | unshift @ISA, $MODEL; |
566 | push @{"$MODEL\::ISA"}, "AnyEvent::Base"; |
793 | push @{"$MODEL\::ISA"}, "AnyEvent::Base"; |
|
|
794 | |
|
|
795 | (shift @post_detect)->() while @post_detect; |
567 | } |
796 | } |
568 | |
797 | |
569 | $MODEL |
798 | $MODEL |
570 | } |
799 | } |
571 | |
800 | |
… | |
… | |
1019 | file descriptor is dup()ed for each watcher. This shows that the dup() |
1248 | file descriptor is dup()ed for each watcher. This shows that the dup() |
1020 | employed by some adaptors is not a big performance issue (it does incur a |
1249 | employed by some adaptors is not a big performance issue (it does incur a |
1021 | hidden memory cost inside the kernel which is not reflected in the figures |
1250 | hidden memory cost inside the kernel which is not reflected in the figures |
1022 | above). |
1251 | above). |
1023 | |
1252 | |
1024 | C<POE>, regardless of underlying event loop (whether using its pure |
1253 | C<POE>, regardless of underlying event loop (whether using its pure perl |
1025 | perl select-based backend or the Event module, the POE-EV backend |
1254 | select-based backend or the Event module, the POE-EV backend couldn't |
1026 | couldn't be tested because it wasn't working) shows abysmal performance |
1255 | be tested because it wasn't working) shows abysmal performance and |
1027 | and memory usage: Watchers use almost 30 times as much memory as |
1256 | memory usage with AnyEvent: Watchers use almost 30 times as much memory |
1028 | EV watchers, and 10 times as much memory as Event (the high memory |
1257 | as EV watchers, and 10 times as much memory as Event (the high memory |
1029 | requirements are caused by requiring a session for each watcher). Watcher |
1258 | requirements are caused by requiring a session for each watcher). Watcher |
1030 | invocation speed is almost 900 times slower than with AnyEvent's pure perl |
1259 | invocation speed is almost 900 times slower than with AnyEvent's pure perl |
|
|
1260 | implementation. |
|
|
1261 | |
1031 | implementation. The design of the POE adaptor class in AnyEvent can not |
1262 | The design of the POE adaptor class in AnyEvent can not really account |
1032 | really account for this, as session creation overhead is small compared |
1263 | for the performance issues, though, as session creation overhead is |
1033 | to execution of the state machine, which is coded pretty optimally within |
1264 | small compared to execution of the state machine, which is coded pretty |
1034 | L<AnyEvent::Impl::POE>. POE simply seems to be abysmally slow. |
1265 | optimally within L<AnyEvent::Impl::POE> (and while everybody agrees that |
|
|
1266 | using multiple sessions is not a good approach, especially regarding |
|
|
1267 | memory usage, even the author of POE could not come up with a faster |
|
|
1268 | design). |
1035 | |
1269 | |
1036 | =head3 Summary |
1270 | =head3 Summary |
1037 | |
1271 | |
1038 | =over 4 |
1272 | =over 4 |
1039 | |
1273 | |
… | |
… | |
1086 | |
1320 | |
1087 | =head3 Results |
1321 | =head3 Results |
1088 | |
1322 | |
1089 | name sockets create request |
1323 | name sockets create request |
1090 | EV 20000 69.01 11.16 |
1324 | EV 20000 69.01 11.16 |
1091 | Perl 20000 75.28 112.76 |
1325 | Perl 20000 73.32 35.87 |
1092 | Event 20000 212.62 257.32 |
1326 | Event 20000 212.62 257.32 |
1093 | Glib 20000 651.16 1896.30 |
1327 | Glib 20000 651.16 1896.30 |
1094 | POE 20000 349.67 12317.24 uses POE::Loop::Event |
1328 | POE 20000 349.67 12317.24 uses POE::Loop::Event |
1095 | |
1329 | |
1096 | =head3 Discussion |
1330 | =head3 Discussion |
… | |
… | |
1118 | |
1352 | |
1119 | =head3 Summary |
1353 | =head3 Summary |
1120 | |
1354 | |
1121 | =over 4 |
1355 | =over 4 |
1122 | |
1356 | |
1123 | =item * The pure perl implementation performs extremely well, considering |
1357 | =item * The pure perl implementation performs extremely well. |
1124 | that it uses select. |
|
|
1125 | |
1358 | |
1126 | =item * Avoid Glib or POE in large projects where performance matters. |
1359 | =item * Avoid Glib or POE in large projects where performance matters. |
1127 | |
1360 | |
1128 | =back |
1361 | =back |
1129 | |
1362 | |
… | |
… | |
1142 | |
1375 | |
1143 | =head3 Results |
1376 | =head3 Results |
1144 | |
1377 | |
1145 | name sockets create request |
1378 | name sockets create request |
1146 | EV 16 20.00 6.54 |
1379 | EV 16 20.00 6.54 |
|
|
1380 | Perl 16 25.75 12.62 |
1147 | Event 16 81.27 35.86 |
1381 | Event 16 81.27 35.86 |
1148 | Glib 16 32.63 15.48 |
1382 | Glib 16 32.63 15.48 |
1149 | Perl 16 24.62 162.37 |
|
|
1150 | POE 16 261.87 276.28 uses POE::Loop::Event |
1383 | POE 16 261.87 276.28 uses POE::Loop::Event |
1151 | |
1384 | |
1152 | =head3 Discussion |
1385 | =head3 Discussion |
1153 | |
1386 | |
1154 | The benchmark tries to test the performance of a typical small |
1387 | The benchmark tries to test the performance of a typical small |
… | |
… | |
1158 | speed most when you have lots of watchers, not when you only have a few of |
1391 | speed most when you have lots of watchers, not when you only have a few of |
1159 | them). |
1392 | them). |
1160 | |
1393 | |
1161 | EV is again fastest. |
1394 | EV is again fastest. |
1162 | |
1395 | |
1163 | The C-based event loops Event and Glib come in second this time, as the |
1396 | Perl again comes second. It is noticably faster than the C-based event |
1164 | overhead of running an iteration is much smaller in C than in Perl (little |
1397 | loops Event and Glib, although the difference is too small to really |
1165 | code to execute in the inner loop, and perl's function calling overhead is |
1398 | matter. |
1166 | high, and updating all the data structures is costly). |
|
|
1167 | |
|
|
1168 | The pure perl event loop is much slower, but still competitive. |
|
|
1169 | |
1399 | |
1170 | POE also performs much better in this case, but is is still far behind the |
1400 | POE also performs much better in this case, but is is still far behind the |
1171 | others. |
1401 | others. |
1172 | |
1402 | |
1173 | =head3 Summary |
1403 | =head3 Summary |
… | |
… | |
1181 | |
1411 | |
1182 | |
1412 | |
1183 | =head1 FORK |
1413 | =head1 FORK |
1184 | |
1414 | |
1185 | Most event libraries are not fork-safe. The ones who are usually are |
1415 | Most event libraries are not fork-safe. The ones who are usually are |
1186 | because they are so inefficient. Only L<EV> is fully fork-aware. |
1416 | because they rely on inefficient but fork-safe C<select> or C<poll> |
|
|
1417 | calls. Only L<EV> is fully fork-aware. |
1187 | |
1418 | |
1188 | If you have to fork, you must either do so I<before> creating your first |
1419 | If you have to fork, you must either do so I<before> creating your first |
1189 | watcher OR you must not use AnyEvent at all in the child. |
1420 | watcher OR you must not use AnyEvent at all in the child. |
1190 | |
1421 | |
1191 | |
1422 | |
… | |
… | |
1203 | |
1434 | |
1204 | BEGIN { delete $ENV{PERL_ANYEVENT_MODEL} } |
1435 | BEGIN { delete $ENV{PERL_ANYEVENT_MODEL} } |
1205 | |
1436 | |
1206 | use AnyEvent; |
1437 | use AnyEvent; |
1207 | |
1438 | |
|
|
1439 | Similar considerations apply to $ENV{PERL_ANYEVENT_VERBOSE}, as that can |
|
|
1440 | be used to probe what backend is used and gain other information (which is |
|
|
1441 | probably even less useful to an attacker than PERL_ANYEVENT_MODEL). |
|
|
1442 | |
1208 | |
1443 | |
1209 | =head1 SEE ALSO |
1444 | =head1 SEE ALSO |
1210 | |
1445 | |
1211 | Event modules: L<Coro::EV>, L<EV>, L<EV::Glib>, L<Glib::EV>, |
1446 | Event modules: L<EV>, L<EV::Glib>, L<Glib::EV>, L<Event>, L<Glib::Event>, |
1212 | L<Coro::Event>, L<Event>, L<Glib::Event>, L<Glib>, L<Coro>, L<Tk>, |
|
|
1213 | L<Event::Lib>, L<Qt>, L<POE>. |
1447 | L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>. |
1214 | |
1448 | |
1215 | Implementations: L<AnyEvent::Impl::CoroEV>, L<AnyEvent::Impl::EV>, |
1449 | Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>, |
1216 | L<AnyEvent::Impl::CoroEvent>, L<AnyEvent::Impl::Event>, L<AnyEvent::Impl::Glib>, |
1450 | L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>, |
1217 | L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>, L<AnyEvent::Impl::EventLib>, |
1451 | L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>, |
1218 | L<AnyEvent::Impl::Qt>, L<AnyEvent::Impl::POE>. |
1452 | L<AnyEvent::Impl::POE>. |
|
|
1453 | |
|
|
1454 | Coroutine support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>, L<Coro::Event>, |
1219 | |
1455 | |
1220 | Nontrivial usage examples: L<Net::FCP>, L<Net::XMPP2>. |
1456 | Nontrivial usage examples: L<Net::FCP>, L<Net::XMPP2>. |
1221 | |
1457 | |
1222 | |
1458 | |
1223 | =head1 AUTHOR |
1459 | =head1 AUTHOR |