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 | |
… | |
… | |
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 |
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20 | $w->send; # wake up current and all future recv's |
20 | $w->wait; # enters "main loop" till $condvar gets ->broadcast |
21 | $w->recv; # enters "main loop" till $condvar gets ->send |
21 | $w->broadcast; # wake up current and all future wait's |
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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? |
… | |
… | |
57 | as those use one of the supported event loops. It is trivial to add new |
57 | as those use one of the supported event loops. It is trivial to add new |
58 | event loops to AnyEvent, too, so it is future-proof). |
58 | event loops to AnyEvent, too, so it is future-proof). |
59 | |
59 | |
60 | In addition to being free of having to use I<the one and only true event |
60 | In addition to being free of having to use I<the one and only true event |
61 | model>, AnyEvent also is free of bloat and policy: with POE or similar |
61 | model>, AnyEvent also is free of bloat and policy: with POE or similar |
62 | modules, you get an enourmous amount of code and strict rules you have to |
62 | modules, you get an enormous amount of code and strict rules you have to |
63 | follow. AnyEvent, on the other hand, is lean and up to the point, by only |
63 | follow. AnyEvent, on the other hand, is lean and up to the point, by only |
64 | offering the functionality that is necessary, in as thin as a wrapper as |
64 | offering the functionality that is necessary, in as thin as a wrapper as |
65 | technically possible. |
65 | technically possible. |
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 | |
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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 | |
70 | |
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 |
… | |
… | |
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 |
… | |
… | |
128 | |
108 | |
129 | =head1 WATCHERS |
109 | =head1 WATCHERS |
130 | |
110 | |
131 | AnyEvent has the central concept of a I<watcher>, which is an object that |
111 | AnyEvent has the central concept of a I<watcher>, which is an object that |
132 | stores relevant data for each kind of event you are waiting for, such as |
112 | stores relevant data for each kind of event you are waiting for, such as |
133 | the callback to call, the filehandle to watch, etc. |
113 | the callback to call, the file handle to watch, etc. |
134 | |
114 | |
135 | These watchers are normal Perl objects with normal Perl lifetime. After |
115 | These watchers are normal Perl objects with normal Perl lifetime. After |
136 | creating a watcher it will immediately "watch" for events and invoke the |
116 | creating a watcher it will immediately "watch" for events and invoke the |
137 | callback when the event occurs (of course, only when the event model |
117 | callback when the event occurs (of course, only when the event model |
138 | is in control). |
118 | is in control). |
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257 | |
237 | |
258 | Although the callback might get passed parameters, their value and |
238 | Although the callback might get passed parameters, their value and |
259 | presence is undefined and you cannot rely on them. Portable AnyEvent |
239 | presence is undefined and you cannot rely on them. Portable AnyEvent |
260 | callbacks cannot use arguments passed to signal watcher callbacks. |
240 | callbacks cannot use arguments passed to signal watcher callbacks. |
261 | |
241 | |
262 | Multiple signal occurances can be clumped together into one callback |
242 | Multiple signal occurrences can be clumped together into one callback |
263 | invocation, and callback invocation will be synchronous. synchronous means |
243 | invocation, and callback invocation will be synchronous. Synchronous means |
264 | that it might take a while until the signal gets handled by the process, |
244 | that it might take a while until the signal gets handled by the process, |
265 | but it is guarenteed not to interrupt any other callbacks. |
245 | but it is guaranteed not to interrupt any other callbacks. |
266 | |
246 | |
267 | The main advantage of using these watchers is that you can share a signal |
247 | The main advantage of using these watchers is that you can share a signal |
268 | between multiple watchers. |
248 | between multiple watchers. |
269 | |
249 | |
270 | This watcher might use C<%SIG>, so programs overwriting those signals |
250 | This watcher might use C<%SIG>, so programs overwriting those signals |
… | |
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299 | |
279 | |
300 | Example: fork a process and wait for it |
280 | Example: fork a process and wait for it |
301 | |
281 | |
302 | my $done = AnyEvent->condvar; |
282 | my $done = AnyEvent->condvar; |
303 | |
283 | |
304 | AnyEvent::detect; # force event module to be initialised |
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305 | |
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306 | my $pid = fork or exit 5; |
284 | my $pid = fork or exit 5; |
307 | |
285 | |
308 | my $w = AnyEvent->child ( |
286 | my $w = AnyEvent->child ( |
309 | pid => $pid, |
287 | pid => $pid, |
310 | cb => sub { |
288 | cb => sub { |
311 | my ($pid, $status) = @_; |
289 | my ($pid, $status) = @_; |
312 | warn "pid $pid exited with status $status"; |
290 | warn "pid $pid exited with status $status"; |
313 | $done->broadcast; |
291 | $done->send; |
314 | }, |
292 | }, |
315 | ); |
293 | ); |
316 | |
294 | |
317 | # do something else, then wait for process exit |
295 | # do something else, then wait for process exit |
318 | $done->wait; |
296 | $done->recv; |
319 | |
297 | |
320 | =head2 CONDITION VARIABLES |
298 | =head2 CONDITION VARIABLES |
321 | |
299 | |
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300 | If you are familiar with some event loops you will know that all of them |
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301 | require you to run some blocking "loop", "run" or similar function that |
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302 | will actively watch for new events and call your callbacks. |
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303 | |
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304 | AnyEvent is different, it expects somebody else to run the event loop and |
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305 | will only block when necessary (usually when told by the user). |
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306 | |
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307 | The instrument to do that is called a "condition variable", so called |
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308 | because they represent a condition that must become true. |
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309 | |
322 | Condition variables can be created by calling the C<< AnyEvent->condvar >> |
310 | Condition variables can be created by calling the C<< AnyEvent->condvar |
323 | method without any arguments. |
311 | >> method, usually without arguments. The only argument pair allowed is |
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312 | C<cb>, which specifies a callback to be called when the condition variable |
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313 | becomes true. |
324 | |
314 | |
325 | A condition variable waits for a condition - precisely that the C<< |
315 | After creation, the condition variable is "false" until it becomes "true" |
326 | ->broadcast >> method has been called. |
316 | by calling the C<send> method (or calling the condition variable as if it |
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317 | were a callback, read about the caveats in the description for the C<< |
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318 | ->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 outstanding events have been processed. And yet |
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323 | another way to call them is transactions - 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<< ->recv >> 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<< ->recv >> 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<< ->recv >> in a round-robin 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: wait for a timer. |
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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->recv; |
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371 | |
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372 | Example: wait for a timer, but take advantage of the fact that |
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373 | condition variables are also code references. |
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374 | |
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375 | my $done = AnyEvent->condvar; |
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376 | my $delay = AnyEvent->timer (after => 5, cb => $done); |
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377 | $done->recv; |
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378 | |
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379 | =head3 METHODS FOR PRODUCERS |
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380 | |
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381 | These methods should only be used by the producing side, i.e. the |
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382 | code/module that eventually sends the signal. Note that it is also |
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383 | the producer side which creates the condvar in most cases, but it isn't |
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384 | uncommon for the consumer to create it as well. |
345 | |
385 | |
346 | =over 4 |
386 | =over 4 |
347 | |
387 | |
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388 | =item $cv->send (...) |
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389 | |
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390 | Flag the condition as ready - a running C<< ->recv >> and all further |
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391 | calls to C<recv> will (eventually) return after this method has been |
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392 | called. If nobody is waiting the send will be remembered. |
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393 | |
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394 | If a callback has been set on the condition variable, it is called |
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395 | immediately from within send. |
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396 | |
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397 | Any arguments passed to the C<send> call will be returned by all |
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398 | future C<< ->recv >> calls. |
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399 | |
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400 | Condition variables are overloaded so one can call them directly |
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401 | (as a code reference). Calling them directly is the same as calling |
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402 | C<send>. Note, however, that many C-based event loops do not handle |
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403 | overloading, so as tempting as it may be, passing a condition variable |
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404 | instead of a callback does not work. Both the pure perl and EV loops |
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405 | support overloading, however, as well as all functions that use perl to |
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406 | invoke a callback (as in L<AnyEvent::Socket> and L<AnyEvent::DNS> for |
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407 | example). |
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408 | |
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409 | =item $cv->croak ($error) |
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410 | |
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411 | Similar to send, but causes all call's to C<< ->recv >> to invoke |
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412 | C<Carp::croak> with the given error message/object/scalar. |
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413 | |
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414 | This can be used to signal any errors to the condition variable |
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415 | user/consumer. |
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416 | |
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417 | =item $cv->begin ([group callback]) |
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418 | |
348 | =item $cv->wait |
419 | =item $cv->end |
349 | |
420 | |
350 | Wait (blocking if necessary) until the C<< ->broadcast >> method has been |
421 | These two methods are EXPERIMENTAL and MIGHT CHANGE. |
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422 | |
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423 | These two methods can be used to combine many transactions/events into |
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424 | one. For example, a function that pings many hosts in parallel might want |
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425 | to use a condition variable for the whole process. |
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426 | |
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427 | Every call to C<< ->begin >> will increment a counter, and every call to |
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428 | C<< ->end >> will decrement it. If the counter reaches C<0> in C<< ->end |
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429 | >>, the (last) callback passed to C<begin> will be executed. That callback |
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430 | is I<supposed> to call C<< ->send >>, but that is not required. If no |
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431 | callback was set, C<send> will be called without any arguments. |
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432 | |
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433 | Let's clarify this with the ping example: |
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434 | |
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435 | my $cv = AnyEvent->condvar; |
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436 | |
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437 | my %result; |
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438 | $cv->begin (sub { $cv->send (\%result) }); |
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439 | |
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440 | for my $host (@list_of_hosts) { |
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441 | $cv->begin; |
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442 | ping_host_then_call_callback $host, sub { |
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443 | $result{$host} = ...; |
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444 | $cv->end; |
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445 | }; |
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446 | } |
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447 | |
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448 | $cv->end; |
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449 | |
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450 | This code fragment supposedly pings a number of hosts and calls |
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451 | C<send> after results for all then have have been gathered - in any |
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452 | order. To achieve this, the code issues a call to C<begin> when it starts |
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453 | each ping request and calls C<end> when it has received some result for |
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454 | it. Since C<begin> and C<end> only maintain a counter, the order in which |
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455 | results arrive is not relevant. |
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456 | |
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457 | There is an additional bracketing call to C<begin> and C<end> outside the |
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458 | loop, which serves two important purposes: first, it sets the callback |
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459 | to be called once the counter reaches C<0>, and second, it ensures that |
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460 | C<send> is called even when C<no> hosts are being pinged (the loop |
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461 | doesn't execute once). |
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462 | |
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463 | This is the general pattern when you "fan out" into multiple subrequests: |
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464 | use an outer C<begin>/C<end> pair to set the callback and ensure C<end> |
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465 | is called at least once, and then, for each subrequest you start, call |
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466 | C<begin> and for each subrequest you finish, call C<end>. |
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467 | |
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468 | =back |
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469 | |
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470 | =head3 METHODS FOR CONSUMERS |
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471 | |
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472 | These methods should only be used by the consuming side, i.e. the |
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473 | code awaits the condition. |
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474 | |
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475 | =over 4 |
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476 | |
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477 | =item $cv->recv |
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478 | |
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479 | Wait (blocking if necessary) until the C<< ->send >> or C<< ->croak |
351 | called on c<$cv>, while servicing other watchers normally. |
480 | >> methods have been called on c<$cv>, while servicing other watchers |
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481 | normally. |
352 | |
482 | |
353 | You can only wait once on a condition - additional calls will return |
483 | You can only wait once on a condition - additional calls are valid but |
354 | immediately. |
484 | will return immediately. |
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485 | |
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486 | If an error condition has been set by calling C<< ->croak >>, then this |
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487 | function will call C<croak>. |
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488 | |
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489 | In list context, all parameters passed to C<send> will be returned, |
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490 | in scalar context only the first one will be returned. |
355 | |
491 | |
356 | Not all event models support a blocking wait - some die in that case |
492 | 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 |
493 | (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 |
494 | 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 |
495 | caller decide whether the call will block or not (for example, by coupling |
360 | condition variables with some kind of request results and supporting |
496 | condition variables with some kind of request results and supporting |
361 | callbacks so the caller knows that getting the result will not block, |
497 | callbacks so the caller knows that getting the result will not block, |
362 | while still suppporting blocking waits if the caller so desires). |
498 | while still supporting blocking waits if the caller so desires). |
363 | |
499 | |
364 | Another reason I<never> to C<< ->wait >> in a module is that you cannot |
500 | Another reason I<never> to C<< ->recv >> in a module is that you cannot |
365 | sensibly have two C<< ->wait >>'s in parallel, as that would require |
501 | sensibly have two C<< ->recv >>'s in parallel, as that would require |
366 | multiple interpreters or coroutines/threads, none of which C<AnyEvent> |
502 | multiple interpreters or coroutines/threads, none of which C<AnyEvent> |
367 | can supply (the coroutine-aware backends L<AnyEvent::Impl::CoroEV> and |
503 | 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 | |
504 | |
371 | =item $cv->broadcast |
505 | The L<Coro> module, however, I<can> and I<does> supply coroutines and, in |
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506 | fact, L<Coro::AnyEvent> replaces AnyEvent's condvars by coroutine-safe |
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507 | versions and also integrates coroutines into AnyEvent, making blocking |
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508 | C<< ->recv >> calls perfectly safe as long as they are done from another |
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509 | coroutine (one that doesn't run the event loop). |
372 | |
510 | |
373 | Flag the condition as ready - a running C<< ->wait >> and all further |
511 | You can ensure that C<< -recv >> never blocks by setting a callback and |
374 | calls to C<wait> will (eventually) return after this method has been |
512 | only calling C<< ->recv >> from within that callback (or at a later |
375 | called. If nobody is waiting the broadcast will be remembered.. |
513 | time). This will work even when the event loop does not support blocking |
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514 | waits otherwise. |
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515 | |
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516 | =item $bool = $cv->ready |
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517 | |
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518 | Returns true when the condition is "true", i.e. whether C<send> or |
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519 | C<croak> have been called. |
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520 | |
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521 | =item $cb = $cv->cb ([new callback]) |
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522 | |
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523 | This is a mutator function that returns the callback set and optionally |
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524 | replaces it before doing so. |
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525 | |
|
|
526 | The callback will be called when the condition becomes "true", i.e. when |
|
|
527 | C<send> or C<croak> are called. Calling C<recv> inside the callback |
|
|
528 | or at any later time is guaranteed not to block. |
376 | |
529 | |
377 | =back |
530 | =back |
378 | |
|
|
379 | Example: |
|
|
380 | |
|
|
381 | # wait till the result is ready |
|
|
382 | my $result_ready = AnyEvent->condvar; |
|
|
383 | |
|
|
384 | # do something such as adding a timer |
|
|
385 | # or socket watcher the calls $result_ready->broadcast |
|
|
386 | # when the "result" is ready. |
|
|
387 | # in this case, we simply use a timer: |
|
|
388 | my $w = AnyEvent->timer ( |
|
|
389 | after => 1, |
|
|
390 | cb => sub { $result_ready->broadcast }, |
|
|
391 | ); |
|
|
392 | |
|
|
393 | # this "blocks" (while handling events) till the watcher |
|
|
394 | # calls broadcast |
|
|
395 | $result_ready->wait; |
|
|
396 | |
531 | |
397 | =head1 GLOBAL VARIABLES AND FUNCTIONS |
532 | =head1 GLOBAL VARIABLES AND FUNCTIONS |
398 | |
533 | |
399 | =over 4 |
534 | =over 4 |
400 | |
535 | |
… | |
… | |
406 | C<AnyEvent::Impl:xxx> modules, but can be any other class in the case |
541 | C<AnyEvent::Impl:xxx> modules, but can be any other class in the case |
407 | AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode>). |
542 | AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode>). |
408 | |
543 | |
409 | The known classes so far are: |
544 | The known classes so far are: |
410 | |
545 | |
411 | AnyEvent::Impl::CoroEV based on Coro::EV, best choice. |
|
|
412 | AnyEvent::Impl::CoroEvent based on Coro::Event, second best choice. |
|
|
413 | AnyEvent::Impl::EV based on EV (an interface to libev, best choice). |
546 | AnyEvent::Impl::EV based on EV (an interface to libev, best choice). |
414 | AnyEvent::Impl::Event based on Event, second best choice. |
547 | AnyEvent::Impl::Event based on Event, second best choice. |
|
|
548 | AnyEvent::Impl::Perl pure-perl implementation, fast and portable. |
415 | AnyEvent::Impl::Glib based on Glib, third-best choice. |
549 | AnyEvent::Impl::Glib based on Glib, third-best choice. |
416 | AnyEvent::Impl::Perl pure-perl implementation, inefficient but portable. |
|
|
417 | AnyEvent::Impl::Tk based on Tk, very bad choice. |
550 | AnyEvent::Impl::Tk based on Tk, very bad choice. |
418 | AnyEvent::Impl::Qt based on Qt, cannot be autoprobed (see its docs). |
551 | AnyEvent::Impl::Qt based on Qt, cannot be autoprobed (see its docs). |
419 | AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse. |
552 | AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse. |
420 | AnyEvent::Impl::POE based on POE, not generic enough for full support. |
553 | AnyEvent::Impl::POE based on POE, not generic enough for full support. |
421 | |
554 | |
… | |
… | |
434 | Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model |
567 | Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model |
435 | if necessary. You should only call this function right before you would |
568 | 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 |
569 | have created an AnyEvent watcher anyway, that is, as late as possible at |
437 | runtime. |
570 | runtime. |
438 | |
571 | |
|
|
572 | =item $guard = AnyEvent::post_detect { BLOCK } |
|
|
573 | |
|
|
574 | Arranges for the code block to be executed as soon as the event model is |
|
|
575 | autodetected (or immediately if this has already happened). |
|
|
576 | |
|
|
577 | If called in scalar or list context, then it creates and returns an object |
|
|
578 | that automatically removes the callback again when it is destroyed. See |
|
|
579 | L<Coro::BDB> for a case where this is useful. |
|
|
580 | |
|
|
581 | =item @AnyEvent::post_detect |
|
|
582 | |
|
|
583 | If there are any code references in this array (you can C<push> to it |
|
|
584 | before or after loading AnyEvent), then they will called directly after |
|
|
585 | the event loop has been chosen. |
|
|
586 | |
|
|
587 | You should check C<$AnyEvent::MODEL> before adding to this array, though: |
|
|
588 | if it contains a true value then the event loop has already been detected, |
|
|
589 | and the array will be ignored. |
|
|
590 | |
|
|
591 | Best use C<AnyEvent::post_detect { BLOCK }> instead. |
|
|
592 | |
439 | =back |
593 | =back |
440 | |
594 | |
441 | =head1 WHAT TO DO IN A MODULE |
595 | =head1 WHAT TO DO IN A MODULE |
442 | |
596 | |
443 | As a module author, you should C<use AnyEvent> and call AnyEvent methods |
597 | As a module author, you should C<use AnyEvent> and call AnyEvent methods |
… | |
… | |
446 | Be careful when you create watchers in the module body - AnyEvent will |
600 | Be careful when you create watchers in the module body - AnyEvent will |
447 | decide which event module to use as soon as the first method is called, so |
601 | 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 |
602 | by calling AnyEvent in your module body you force the user of your module |
449 | to load the event module first. |
603 | to load the event module first. |
450 | |
604 | |
451 | Never call C<< ->wait >> on a condition variable unless you I<know> that |
605 | Never call C<< ->recv >> on a condition variable unless you I<know> that |
452 | the C<< ->broadcast >> method has been called on it already. This is |
606 | 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 |
607 | because it will stall the whole program, and the whole point of using |
454 | events is to stay interactive. |
608 | events is to stay interactive. |
455 | |
609 | |
456 | It is fine, however, to call C<< ->wait >> when the user of your module |
610 | It is fine, however, to call C<< ->recv >> when the user of your module |
457 | requests it (i.e. if you create a http request object ad have a method |
611 | requests it (i.e. if you create a http request object ad have a method |
458 | called C<results> that returns the results, it should call C<< ->wait >> |
612 | called C<results> that returns the results, it should call C<< ->recv >> |
459 | freely, as the user of your module knows what she is doing. always). |
613 | freely, as the user of your module knows what she is doing. always). |
460 | |
614 | |
461 | =head1 WHAT TO DO IN THE MAIN PROGRAM |
615 | =head1 WHAT TO DO IN THE MAIN PROGRAM |
462 | |
616 | |
463 | There will always be a single main program - the only place that should |
617 | There will always be a single main program - the only place that should |
… | |
… | |
465 | |
619 | |
466 | If it doesn't care, it can just "use AnyEvent" and use it itself, or not |
620 | If it doesn't care, it can just "use AnyEvent" and use it itself, or not |
467 | do anything special (it does not need to be event-based) and let AnyEvent |
621 | do anything special (it does not need to be event-based) and let AnyEvent |
468 | decide which implementation to chose if some module relies on it. |
622 | decide which implementation to chose if some module relies on it. |
469 | |
623 | |
470 | If the main program relies on a specific event model. For example, in |
624 | If the main program relies on a specific event model - for example, in |
471 | Gtk2 programs you have to rely on the Glib module. You should load the |
625 | Gtk2 programs you have to rely on the Glib module - you should load the |
472 | event module before loading AnyEvent or any module that uses it: generally |
626 | event module before loading AnyEvent or any module that uses it: generally |
473 | speaking, you should load it as early as possible. The reason is that |
627 | speaking, you should load it as early as possible. The reason is that |
474 | modules might create watchers when they are loaded, and AnyEvent will |
628 | modules might create watchers when they are loaded, and AnyEvent will |
475 | decide on the event model to use as soon as it creates watchers, and it |
629 | decide on the event model to use as soon as it creates watchers, and it |
476 | might chose the wrong one unless you load the correct one yourself. |
630 | might chose the wrong one unless you load the correct one yourself. |
477 | |
631 | |
478 | You can chose to use a rather inefficient pure-perl implementation by |
632 | You can chose to use a pure-perl implementation by loading the |
479 | loading the C<AnyEvent::Impl::Perl> module, which gives you similar |
633 | C<AnyEvent::Impl::Perl> module, which gives you similar behaviour |
480 | behaviour everywhere, but letting AnyEvent chose is generally better. |
634 | everywhere, but letting AnyEvent chose the model is generally better. |
|
|
635 | |
|
|
636 | =head2 MAINLOOP EMULATION |
|
|
637 | |
|
|
638 | Sometimes (often for short test scripts, or even standalone programs who |
|
|
639 | only want to use AnyEvent), you do not want to run a specific event loop. |
|
|
640 | |
|
|
641 | In that case, you can use a condition variable like this: |
|
|
642 | |
|
|
643 | AnyEvent->condvar->recv; |
|
|
644 | |
|
|
645 | This has the effect of entering the event loop and looping forever. |
|
|
646 | |
|
|
647 | Note that usually your program has some exit condition, in which case |
|
|
648 | it is better to use the "traditional" approach of storing a condition |
|
|
649 | variable somewhere, waiting for it, and sending it when the program should |
|
|
650 | exit cleanly. |
|
|
651 | |
|
|
652 | |
|
|
653 | =head1 OTHER MODULES |
|
|
654 | |
|
|
655 | The following is a non-exhaustive list of additional modules that use |
|
|
656 | AnyEvent and can therefore be mixed easily with other AnyEvent modules |
|
|
657 | in the same program. Some of the modules come with AnyEvent, some are |
|
|
658 | available via CPAN. |
|
|
659 | |
|
|
660 | =over 4 |
|
|
661 | |
|
|
662 | =item L<AnyEvent::Util> |
|
|
663 | |
|
|
664 | Contains various utility functions that replace often-used but blocking |
|
|
665 | functions such as C<inet_aton> by event-/callback-based versions. |
|
|
666 | |
|
|
667 | =item L<AnyEvent::Handle> |
|
|
668 | |
|
|
669 | Provide read and write buffers and manages watchers for reads and writes. |
|
|
670 | |
|
|
671 | =item L<AnyEvent::Socket> |
|
|
672 | |
|
|
673 | Provides various utility functions for (internet protocol) sockets, |
|
|
674 | addresses and name resolution. Also functions to create non-blocking tcp |
|
|
675 | connections or tcp servers, with IPv6 and SRV record support and more. |
|
|
676 | |
|
|
677 | =item L<AnyEvent::DNS> |
|
|
678 | |
|
|
679 | Provides rich asynchronous DNS resolver capabilities. |
|
|
680 | |
|
|
681 | =item L<AnyEvent::HTTPD> |
|
|
682 | |
|
|
683 | Provides a simple web application server framework. |
|
|
684 | |
|
|
685 | =item L<AnyEvent::FastPing> |
|
|
686 | |
|
|
687 | The fastest ping in the west. |
|
|
688 | |
|
|
689 | =item L<Net::IRC3> |
|
|
690 | |
|
|
691 | AnyEvent based IRC client module family. |
|
|
692 | |
|
|
693 | =item L<Net::XMPP2> |
|
|
694 | |
|
|
695 | AnyEvent based XMPP (Jabber protocol) module family. |
|
|
696 | |
|
|
697 | =item L<Net::FCP> |
|
|
698 | |
|
|
699 | AnyEvent-based implementation of the Freenet Client Protocol, birthplace |
|
|
700 | of AnyEvent. |
|
|
701 | |
|
|
702 | =item L<Event::ExecFlow> |
|
|
703 | |
|
|
704 | High level API for event-based execution flow control. |
|
|
705 | |
|
|
706 | =item L<Coro> |
|
|
707 | |
|
|
708 | Has special support for AnyEvent via L<Coro::AnyEvent>. |
|
|
709 | |
|
|
710 | =item L<AnyEvent::AIO>, L<IO::AIO> |
|
|
711 | |
|
|
712 | Truly asynchronous I/O, should be in the toolbox of every event |
|
|
713 | programmer. AnyEvent::AIO transparently fuses IO::AIO and AnyEvent |
|
|
714 | together. |
|
|
715 | |
|
|
716 | =item L<AnyEvent::BDB>, L<BDB> |
|
|
717 | |
|
|
718 | Truly asynchronous Berkeley DB access. AnyEvent::AIO transparently fuses |
|
|
719 | IO::AIO and AnyEvent together. |
|
|
720 | |
|
|
721 | =item L<IO::Lambda> |
|
|
722 | |
|
|
723 | The lambda approach to I/O - don't ask, look there. Can use AnyEvent. |
|
|
724 | |
|
|
725 | =back |
481 | |
726 | |
482 | =cut |
727 | =cut |
483 | |
728 | |
484 | package AnyEvent; |
729 | package AnyEvent; |
485 | |
730 | |
486 | no warnings; |
731 | no warnings; |
487 | use strict; |
732 | use strict; |
488 | |
733 | |
489 | use Carp; |
734 | use Carp; |
490 | |
735 | |
491 | our $VERSION = '3.3'; |
736 | our $VERSION = '4.03'; |
492 | our $MODEL; |
737 | our $MODEL; |
493 | |
738 | |
494 | our $AUTOLOAD; |
739 | our $AUTOLOAD; |
495 | our @ISA; |
740 | our @ISA; |
496 | |
741 | |
|
|
742 | our @REGISTRY; |
|
|
743 | |
497 | our $verbose = $ENV{PERL_ANYEVENT_VERBOSE}*1; |
744 | our $verbose = $ENV{PERL_ANYEVENT_VERBOSE}*1; |
498 | |
745 | |
499 | our @REGISTRY; |
746 | our %PROTOCOL; # (ipv4|ipv6) => (1|2), higher numbers are preferred |
|
|
747 | |
|
|
748 | { |
|
|
749 | my $idx; |
|
|
750 | $PROTOCOL{$_} = ++$idx |
|
|
751 | for reverse split /\s*,\s*/, |
|
|
752 | $ENV{PERL_ANYEVENT_PROTOCOLS} || "ipv4,ipv6"; |
|
|
753 | } |
500 | |
754 | |
501 | my @models = ( |
755 | my @models = ( |
502 | [Coro::EV:: => AnyEvent::Impl::CoroEV::], |
|
|
503 | [Coro::Event:: => AnyEvent::Impl::CoroEvent::], |
|
|
504 | [EV:: => AnyEvent::Impl::EV::], |
756 | [EV:: => AnyEvent::Impl::EV::], |
505 | [Event:: => AnyEvent::Impl::Event::], |
757 | [Event:: => AnyEvent::Impl::Event::], |
506 | [Glib:: => AnyEvent::Impl::Glib::], |
|
|
507 | [Tk:: => AnyEvent::Impl::Tk::], |
|
|
508 | [Wx:: => AnyEvent::Impl::POE::], |
|
|
509 | [Prima:: => AnyEvent::Impl::POE::], |
|
|
510 | [AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl::], |
758 | [AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl::], |
511 | # everything below here will not be autoprobed as the pureperl backend should work everywhere |
759 | # everything below here will not be autoprobed |
|
|
760 | # as the pureperl backend should work everywhere |
|
|
761 | # and is usually faster |
|
|
762 | [Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles |
|
|
763 | [Glib:: => AnyEvent::Impl::Glib::], # becomes extremely slow with many watchers |
512 | [Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy |
764 | [Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy |
513 | [Qt:: => AnyEvent::Impl::Qt::], # requires special main program |
765 | [Qt:: => AnyEvent::Impl::Qt::], # requires special main program |
514 | [POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza |
766 | [POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza |
|
|
767 | [Wx:: => AnyEvent::Impl::POE::], |
|
|
768 | [Prima:: => AnyEvent::Impl::POE::], |
515 | ); |
769 | ); |
516 | |
770 | |
517 | our %method = map +($_ => 1), qw(io timer signal child condvar broadcast wait one_event DESTROY); |
771 | our %method = map +($_ => 1), qw(io timer signal child condvar one_event DESTROY); |
|
|
772 | |
|
|
773 | our @post_detect; |
|
|
774 | |
|
|
775 | sub post_detect(&) { |
|
|
776 | my ($cb) = @_; |
|
|
777 | |
|
|
778 | if ($MODEL) { |
|
|
779 | $cb->(); |
|
|
780 | |
|
|
781 | 1 |
|
|
782 | } else { |
|
|
783 | push @post_detect, $cb; |
|
|
784 | |
|
|
785 | defined wantarray |
|
|
786 | ? bless \$cb, "AnyEvent::Util::PostDetect" |
|
|
787 | : () |
|
|
788 | } |
|
|
789 | } |
|
|
790 | |
|
|
791 | sub AnyEvent::Util::PostDetect::DESTROY { |
|
|
792 | @post_detect = grep $_ != ${$_[0]}, @post_detect; |
|
|
793 | } |
518 | |
794 | |
519 | sub detect() { |
795 | sub detect() { |
520 | unless ($MODEL) { |
796 | unless ($MODEL) { |
521 | no strict 'refs'; |
797 | no strict 'refs'; |
522 | |
798 | |
… | |
… | |
556 | last; |
832 | last; |
557 | } |
833 | } |
558 | } |
834 | } |
559 | |
835 | |
560 | $MODEL |
836 | $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."; |
837 | or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV, Event or Glib."; |
562 | } |
838 | } |
563 | } |
839 | } |
564 | |
840 | |
565 | unshift @ISA, $MODEL; |
841 | unshift @ISA, $MODEL; |
566 | push @{"$MODEL\::ISA"}, "AnyEvent::Base"; |
842 | push @{"$MODEL\::ISA"}, "AnyEvent::Base"; |
|
|
843 | |
|
|
844 | (shift @post_detect)->() while @post_detect; |
567 | } |
845 | } |
568 | |
846 | |
569 | $MODEL |
847 | $MODEL |
570 | } |
848 | } |
571 | |
849 | |
… | |
… | |
581 | $class->$func (@_); |
859 | $class->$func (@_); |
582 | } |
860 | } |
583 | |
861 | |
584 | package AnyEvent::Base; |
862 | package AnyEvent::Base; |
585 | |
863 | |
586 | # default implementation for ->condvar, ->wait, ->broadcast |
864 | # default implementation for ->condvar |
587 | |
865 | |
588 | sub condvar { |
866 | sub condvar { |
589 | bless \my $flag, "AnyEvent::Base::CondVar" |
867 | bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, AnyEvent::CondVar:: |
590 | } |
|
|
591 | |
|
|
592 | sub AnyEvent::Base::CondVar::broadcast { |
|
|
593 | ${$_[0]}++; |
|
|
594 | } |
|
|
595 | |
|
|
596 | sub AnyEvent::Base::CondVar::wait { |
|
|
597 | AnyEvent->one_event while !${$_[0]}; |
|
|
598 | } |
868 | } |
599 | |
869 | |
600 | # default implementation for ->signal |
870 | # default implementation for ->signal |
601 | |
871 | |
602 | our %SIG_CB; |
872 | our %SIG_CB; |
… | |
… | |
676 | delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} }; |
946 | delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} }; |
677 | |
947 | |
678 | undef $CHLD_W unless keys %PID_CB; |
948 | undef $CHLD_W unless keys %PID_CB; |
679 | } |
949 | } |
680 | |
950 | |
|
|
951 | package AnyEvent::CondVar; |
|
|
952 | |
|
|
953 | our @ISA = AnyEvent::CondVar::Base::; |
|
|
954 | |
|
|
955 | package AnyEvent::CondVar::Base; |
|
|
956 | |
|
|
957 | use overload |
|
|
958 | '&{}' => sub { my $self = shift; sub { $self->send (@_) } }, |
|
|
959 | fallback => 1; |
|
|
960 | |
|
|
961 | sub _send { |
|
|
962 | # nop |
|
|
963 | } |
|
|
964 | |
|
|
965 | sub send { |
|
|
966 | my $cv = shift; |
|
|
967 | $cv->{_ae_sent} = [@_]; |
|
|
968 | (delete $cv->{_ae_cb})->($cv) if $cv->{_ae_cb}; |
|
|
969 | $cv->_send; |
|
|
970 | } |
|
|
971 | |
|
|
972 | sub croak { |
|
|
973 | $_[0]{_ae_croak} = $_[1]; |
|
|
974 | $_[0]->send; |
|
|
975 | } |
|
|
976 | |
|
|
977 | sub ready { |
|
|
978 | $_[0]{_ae_sent} |
|
|
979 | } |
|
|
980 | |
|
|
981 | sub _wait { |
|
|
982 | AnyEvent->one_event while !$_[0]{_ae_sent}; |
|
|
983 | } |
|
|
984 | |
|
|
985 | sub recv { |
|
|
986 | $_[0]->_wait; |
|
|
987 | |
|
|
988 | Carp::croak $_[0]{_ae_croak} if $_[0]{_ae_croak}; |
|
|
989 | wantarray ? @{ $_[0]{_ae_sent} } : $_[0]{_ae_sent}[0] |
|
|
990 | } |
|
|
991 | |
|
|
992 | sub cb { |
|
|
993 | $_[0]{_ae_cb} = $_[1] if @_ > 1; |
|
|
994 | $_[0]{_ae_cb} |
|
|
995 | } |
|
|
996 | |
|
|
997 | sub begin { |
|
|
998 | ++$_[0]{_ae_counter}; |
|
|
999 | $_[0]{_ae_end_cb} = $_[1] if @_ > 1; |
|
|
1000 | } |
|
|
1001 | |
|
|
1002 | sub end { |
|
|
1003 | return if --$_[0]{_ae_counter}; |
|
|
1004 | &{ $_[0]{_ae_end_cb} || sub { $_[0]->send } }; |
|
|
1005 | } |
|
|
1006 | |
|
|
1007 | # undocumented/compatibility with pre-3.4 |
|
|
1008 | *broadcast = \&send; |
|
|
1009 | *wait = \&_wait; |
|
|
1010 | |
681 | =head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE |
1011 | =head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE |
682 | |
1012 | |
683 | This is an advanced topic that you do not normally need to use AnyEvent in |
1013 | This is an advanced topic that you do not normally need to use AnyEvent in |
684 | a module. This section is only of use to event loop authors who want to |
1014 | a module. This section is only of use to event loop authors who want to |
685 | provide AnyEvent compatibility. |
1015 | provide AnyEvent compatibility. |
… | |
… | |
741 | model it chooses. |
1071 | model it chooses. |
742 | |
1072 | |
743 | =item C<PERL_ANYEVENT_MODEL> |
1073 | =item C<PERL_ANYEVENT_MODEL> |
744 | |
1074 | |
745 | This can be used to specify the event model to be used by AnyEvent, before |
1075 | This can be used to specify the event model to be used by AnyEvent, before |
746 | autodetection and -probing kicks in. It must be a string consisting |
1076 | auto detection and -probing kicks in. It must be a string consisting |
747 | entirely of ASCII letters. The string C<AnyEvent::Impl::> gets prepended |
1077 | entirely of ASCII letters. The string C<AnyEvent::Impl::> gets prepended |
748 | and the resulting module name is loaded and if the load was successful, |
1078 | and the resulting module name is loaded and if the load was successful, |
749 | used as event model. If it fails to load AnyEvent will proceed with |
1079 | used as event model. If it fails to load AnyEvent will proceed with |
750 | autodetection and -probing. |
1080 | auto detection and -probing. |
751 | |
1081 | |
752 | This functionality might change in future versions. |
1082 | This functionality might change in future versions. |
753 | |
1083 | |
754 | For example, to force the pure perl model (L<AnyEvent::Impl::Perl>) you |
1084 | For example, to force the pure perl model (L<AnyEvent::Impl::Perl>) you |
755 | could start your program like this: |
1085 | could start your program like this: |
756 | |
1086 | |
757 | PERL_ANYEVENT_MODEL=Perl perl ... |
1087 | PERL_ANYEVENT_MODEL=Perl perl ... |
|
|
1088 | |
|
|
1089 | =item C<PERL_ANYEVENT_PROTOCOLS> |
|
|
1090 | |
|
|
1091 | Used by both L<AnyEvent::DNS> and L<AnyEvent::Socket> to determine preferences |
|
|
1092 | for IPv4 or IPv6. The default is unspecified (and might change, or be the result |
|
|
1093 | of auto probing). |
|
|
1094 | |
|
|
1095 | Must be set to a comma-separated list of protocols or address families, |
|
|
1096 | current supported: C<ipv4> and C<ipv6>. Only protocols mentioned will be |
|
|
1097 | used, and preference will be given to protocols mentioned earlier in the |
|
|
1098 | list. |
|
|
1099 | |
|
|
1100 | This variable can effectively be used for denial-of-service attacks |
|
|
1101 | against local programs (e.g. when setuid), although the impact is likely |
|
|
1102 | small, as the program has to handle connection errors already- |
|
|
1103 | |
|
|
1104 | Examples: C<PERL_ANYEVENT_PROTOCOLS=ipv4,ipv6> - prefer IPv4 over IPv6, |
|
|
1105 | but support both and try to use both. C<PERL_ANYEVENT_PROTOCOLS=ipv4> |
|
|
1106 | - only support IPv4, never try to resolve or contact IPv6 |
|
|
1107 | addresses. C<PERL_ANYEVENT_PROTOCOLS=ipv6,ipv4> support either IPv4 or |
|
|
1108 | IPv6, but prefer IPv6 over IPv4. |
|
|
1109 | |
|
|
1110 | =item C<PERL_ANYEVENT_EDNS0> |
|
|
1111 | |
|
|
1112 | Used by L<AnyEvent::DNS> to decide whether to use the EDNS0 extension |
|
|
1113 | for DNS. This extension is generally useful to reduce DNS traffic, but |
|
|
1114 | some (broken) firewalls drop such DNS packets, which is why it is off by |
|
|
1115 | default. |
|
|
1116 | |
|
|
1117 | Setting this variable to C<1> will cause L<AnyEvent::DNS> to announce |
|
|
1118 | EDNS0 in its DNS requests. |
758 | |
1119 | |
759 | =back |
1120 | =back |
760 | |
1121 | |
761 | =head1 EXAMPLE PROGRAM |
1122 | =head1 EXAMPLE PROGRAM |
762 | |
1123 | |
… | |
… | |
773 | poll => 'r', |
1134 | poll => 'r', |
774 | cb => sub { |
1135 | cb => sub { |
775 | warn "io event <$_[0]>\n"; # will always output <r> |
1136 | warn "io event <$_[0]>\n"; # will always output <r> |
776 | chomp (my $input = <STDIN>); # read a line |
1137 | chomp (my $input = <STDIN>); # read a line |
777 | warn "read: $input\n"; # output what has been read |
1138 | warn "read: $input\n"; # output what has been read |
778 | $cv->broadcast if $input =~ /^q/i; # quit program if /^q/i |
1139 | $cv->send if $input =~ /^q/i; # quit program if /^q/i |
779 | }, |
1140 | }, |
780 | ); |
1141 | ); |
781 | |
1142 | |
782 | my $time_watcher; # can only be used once |
1143 | my $time_watcher; # can only be used once |
783 | |
1144 | |
… | |
… | |
788 | }); |
1149 | }); |
789 | } |
1150 | } |
790 | |
1151 | |
791 | new_timer; # create first timer |
1152 | new_timer; # create first timer |
792 | |
1153 | |
793 | $cv->wait; # wait until user enters /^q/i |
1154 | $cv->recv; # wait until user enters /^q/i |
794 | |
1155 | |
795 | =head1 REAL-WORLD EXAMPLE |
1156 | =head1 REAL-WORLD EXAMPLE |
796 | |
1157 | |
797 | Consider the L<Net::FCP> module. It features (among others) the following |
1158 | Consider the L<Net::FCP> module. It features (among others) the following |
798 | API calls, which are to freenet what HTTP GET requests are to http: |
1159 | API calls, which are to freenet what HTTP GET requests are to http: |
… | |
… | |
848 | syswrite $txn->{fh}, $txn->{request} |
1209 | syswrite $txn->{fh}, $txn->{request} |
849 | or die "connection or write error"; |
1210 | or die "connection or write error"; |
850 | $txn->{w} = AnyEvent->io (fh => $txn->{fh}, poll => 'r', cb => sub { $txn->fh_ready_r }); |
1211 | $txn->{w} = AnyEvent->io (fh => $txn->{fh}, poll => 'r', cb => sub { $txn->fh_ready_r }); |
851 | |
1212 | |
852 | Again, C<fh_ready_r> waits till all data has arrived, and then stores the |
1213 | Again, C<fh_ready_r> waits till all data has arrived, and then stores the |
853 | result and signals any possible waiters that the request ahs finished: |
1214 | result and signals any possible waiters that the request has finished: |
854 | |
1215 | |
855 | sysread $txn->{fh}, $txn->{buf}, length $txn->{$buf}; |
1216 | sysread $txn->{fh}, $txn->{buf}, length $txn->{$buf}; |
856 | |
1217 | |
857 | if (end-of-file or data complete) { |
1218 | if (end-of-file or data complete) { |
858 | $txn->{result} = $txn->{buf}; |
1219 | $txn->{result} = $txn->{buf}; |
859 | $txn->{finished}->broadcast; |
1220 | $txn->{finished}->send; |
860 | $txb->{cb}->($txn) of $txn->{cb}; # also call callback |
1221 | $txb->{cb}->($txn) of $txn->{cb}; # also call callback |
861 | } |
1222 | } |
862 | |
1223 | |
863 | The C<result> method, finally, just waits for the finished signal (if the |
1224 | The C<result> method, finally, just waits for the finished signal (if the |
864 | request was already finished, it doesn't wait, of course, and returns the |
1225 | request was already finished, it doesn't wait, of course, and returns the |
865 | data: |
1226 | data: |
866 | |
1227 | |
867 | $txn->{finished}->wait; |
1228 | $txn->{finished}->recv; |
868 | return $txn->{result}; |
1229 | return $txn->{result}; |
869 | |
1230 | |
870 | The actual code goes further and collects all errors (C<die>s, exceptions) |
1231 | The actual code goes further and collects all errors (C<die>s, exceptions) |
871 | that occured during request processing. The C<result> method detects |
1232 | that occurred during request processing. The C<result> method detects |
872 | whether an exception as thrown (it is stored inside the $txn object) |
1233 | whether an exception as thrown (it is stored inside the $txn object) |
873 | and just throws the exception, which means connection errors and other |
1234 | and just throws the exception, which means connection errors and other |
874 | problems get reported tot he code that tries to use the result, not in a |
1235 | problems get reported tot he code that tries to use the result, not in a |
875 | random callback. |
1236 | random callback. |
876 | |
1237 | |
… | |
… | |
907 | |
1268 | |
908 | my $quit = AnyEvent->condvar; |
1269 | my $quit = AnyEvent->condvar; |
909 | |
1270 | |
910 | $fcp->txn_client_get ($url)->cb (sub { |
1271 | $fcp->txn_client_get ($url)->cb (sub { |
911 | ... |
1272 | ... |
912 | $quit->broadcast; |
1273 | $quit->send; |
913 | }); |
1274 | }); |
914 | |
1275 | |
915 | $quit->wait; |
1276 | $quit->recv; |
916 | |
1277 | |
917 | |
1278 | |
918 | =head1 BENCHMARKS |
1279 | =head1 BENCHMARKS |
919 | |
1280 | |
920 | To give you an idea of the performance and overheads that AnyEvent adds |
1281 | To give you an idea of the performance and overheads that AnyEvent adds |
… | |
… | |
922 | of various event loops I prepared some benchmarks. |
1283 | of various event loops I prepared some benchmarks. |
923 | |
1284 | |
924 | =head2 BENCHMARKING ANYEVENT OVERHEAD |
1285 | =head2 BENCHMARKING ANYEVENT OVERHEAD |
925 | |
1286 | |
926 | Here is a benchmark of various supported event models used natively and |
1287 | Here is a benchmark of various supported event models used natively and |
927 | through anyevent. The benchmark creates a lot of timers (with a zero |
1288 | through AnyEvent. The benchmark creates a lot of timers (with a zero |
928 | timeout) and I/O watchers (watching STDOUT, a pty, to become writable, |
1289 | timeout) and I/O watchers (watching STDOUT, a pty, to become writable, |
929 | which it is), lets them fire exactly once and destroys them again. |
1290 | which it is), lets them fire exactly once and destroys them again. |
930 | |
1291 | |
931 | Source code for this benchmark is found as F<eg/bench> in the AnyEvent |
1292 | Source code for this benchmark is found as F<eg/bench> in the AnyEvent |
932 | distribution. |
1293 | distribution. |
… | |
… | |
949 | all watchers, to avoid adding memory overhead. That means closure creation |
1310 | all watchers, to avoid adding memory overhead. That means closure creation |
950 | and memory usage is not included in the figures. |
1311 | and memory usage is not included in the figures. |
951 | |
1312 | |
952 | I<invoke> is the time, in microseconds, used to invoke a simple |
1313 | I<invoke> is the time, in microseconds, used to invoke a simple |
953 | callback. The callback simply counts down a Perl variable and after it was |
1314 | callback. The callback simply counts down a Perl variable and after it was |
954 | invoked "watcher" times, it would C<< ->broadcast >> a condvar once to |
1315 | invoked "watcher" times, it would C<< ->send >> a condvar once to |
955 | signal the end of this phase. |
1316 | signal the end of this phase. |
956 | |
1317 | |
957 | I<destroy> is the time, in microseconds, that it takes to destroy a single |
1318 | I<destroy> is the time, in microseconds, that it takes to destroy a single |
958 | watcher. |
1319 | watcher. |
959 | |
1320 | |
… | |
… | |
1019 | file descriptor is dup()ed for each watcher. This shows that the dup() |
1380 | 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 |
1381 | 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 |
1382 | hidden memory cost inside the kernel which is not reflected in the figures |
1022 | above). |
1383 | above). |
1023 | |
1384 | |
1024 | C<POE>, regardless of underlying event loop (whether using its pure |
1385 | 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 |
1386 | 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 |
1387 | be tested because it wasn't working) shows abysmal performance and |
1027 | and memory usage: Watchers use almost 30 times as much memory as |
1388 | 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 |
1389 | 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 |
1390 | 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 |
1391 | invocation speed is almost 900 times slower than with AnyEvent's pure perl |
|
|
1392 | implementation. |
|
|
1393 | |
1031 | implementation. The design of the POE adaptor class in AnyEvent can not |
1394 | 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 |
1395 | for the performance issues, though, as session creation overhead is |
1033 | to execution of the state machine, which is coded pretty optimally within |
1396 | small compared to execution of the state machine, which is coded pretty |
1034 | L<AnyEvent::Impl::POE>. POE simply seems to be abysmally slow. |
1397 | optimally within L<AnyEvent::Impl::POE> (and while everybody agrees that |
|
|
1398 | using multiple sessions is not a good approach, especially regarding |
|
|
1399 | memory usage, even the author of POE could not come up with a faster |
|
|
1400 | design). |
1035 | |
1401 | |
1036 | =head3 Summary |
1402 | =head3 Summary |
1037 | |
1403 | |
1038 | =over 4 |
1404 | =over 4 |
1039 | |
1405 | |
… | |
… | |
1050 | |
1416 | |
1051 | =back |
1417 | =back |
1052 | |
1418 | |
1053 | =head2 BENCHMARKING THE LARGE SERVER CASE |
1419 | =head2 BENCHMARKING THE LARGE SERVER CASE |
1054 | |
1420 | |
1055 | This benchmark atcually benchmarks the event loop itself. It works by |
1421 | This benchmark actually benchmarks the event loop itself. It works by |
1056 | creating a number of "servers": each server consists of a socketpair, a |
1422 | creating a number of "servers": each server consists of a socket pair, a |
1057 | timeout watcher that gets reset on activity (but never fires), and an I/O |
1423 | timeout watcher that gets reset on activity (but never fires), and an I/O |
1058 | watcher waiting for input on one side of the socket. Each time the socket |
1424 | watcher waiting for input on one side of the socket. Each time the socket |
1059 | watcher reads a byte it will write that byte to a random other "server". |
1425 | watcher reads a byte it will write that byte to a random other "server". |
1060 | |
1426 | |
1061 | The effect is that there will be a lot of I/O watchers, only part of which |
1427 | The effect is that there will be a lot of I/O watchers, only part of which |
1062 | are active at any one point (so there is a constant number of active |
1428 | are active at any one point (so there is a constant number of active |
1063 | fds for each loop iterstaion, but which fds these are is random). The |
1429 | fds for each loop iteration, but which fds these are is random). The |
1064 | timeout is reset each time something is read because that reflects how |
1430 | timeout is reset each time something is read because that reflects how |
1065 | most timeouts work (and puts extra pressure on the event loops). |
1431 | most timeouts work (and puts extra pressure on the event loops). |
1066 | |
1432 | |
1067 | In this benchmark, we use 10000 socketpairs (20000 sockets), of which 100 |
1433 | In this benchmark, we use 10000 socket pairs (20000 sockets), of which 100 |
1068 | (1%) are active. This mirrors the activity of large servers with many |
1434 | (1%) are active. This mirrors the activity of large servers with many |
1069 | connections, most of which are idle at any one point in time. |
1435 | connections, most of which are idle at any one point in time. |
1070 | |
1436 | |
1071 | Source code for this benchmark is found as F<eg/bench2> in the AnyEvent |
1437 | Source code for this benchmark is found as F<eg/bench2> in the AnyEvent |
1072 | distribution. |
1438 | distribution. |
… | |
… | |
1074 | =head3 Explanation of the columns |
1440 | =head3 Explanation of the columns |
1075 | |
1441 | |
1076 | I<sockets> is the number of sockets, and twice the number of "servers" (as |
1442 | I<sockets> is the number of sockets, and twice the number of "servers" (as |
1077 | each server has a read and write socket end). |
1443 | each server has a read and write socket end). |
1078 | |
1444 | |
1079 | I<create> is the time it takes to create a socketpair (which is |
1445 | I<create> is the time it takes to create a socket pair (which is |
1080 | nontrivial) and two watchers: an I/O watcher and a timeout watcher. |
1446 | nontrivial) and two watchers: an I/O watcher and a timeout watcher. |
1081 | |
1447 | |
1082 | I<request>, the most important value, is the time it takes to handle a |
1448 | I<request>, the most important value, is the time it takes to handle a |
1083 | single "request", that is, reading the token from the pipe and forwarding |
1449 | single "request", that is, reading the token from the pipe and forwarding |
1084 | it to another server. This includes deleting the old timeout and creating |
1450 | it to another server. This includes deleting the old timeout and creating |
… | |
… | |
1086 | |
1452 | |
1087 | =head3 Results |
1453 | =head3 Results |
1088 | |
1454 | |
1089 | name sockets create request |
1455 | name sockets create request |
1090 | EV 20000 69.01 11.16 |
1456 | EV 20000 69.01 11.16 |
1091 | Perl 20000 75.28 112.76 |
1457 | Perl 20000 73.32 35.87 |
1092 | Event 20000 212.62 257.32 |
1458 | Event 20000 212.62 257.32 |
1093 | Glib 20000 651.16 1896.30 |
1459 | Glib 20000 651.16 1896.30 |
1094 | POE 20000 349.67 12317.24 uses POE::Loop::Event |
1460 | POE 20000 349.67 12317.24 uses POE::Loop::Event |
1095 | |
1461 | |
1096 | =head3 Discussion |
1462 | =head3 Discussion |
… | |
… | |
1118 | |
1484 | |
1119 | =head3 Summary |
1485 | =head3 Summary |
1120 | |
1486 | |
1121 | =over 4 |
1487 | =over 4 |
1122 | |
1488 | |
1123 | =item * The pure perl implementation performs extremely well, considering |
1489 | =item * The pure perl implementation performs extremely well. |
1124 | that it uses select. |
|
|
1125 | |
1490 | |
1126 | =item * Avoid Glib or POE in large projects where performance matters. |
1491 | =item * Avoid Glib or POE in large projects where performance matters. |
1127 | |
1492 | |
1128 | =back |
1493 | =back |
1129 | |
1494 | |
… | |
… | |
1142 | |
1507 | |
1143 | =head3 Results |
1508 | =head3 Results |
1144 | |
1509 | |
1145 | name sockets create request |
1510 | name sockets create request |
1146 | EV 16 20.00 6.54 |
1511 | EV 16 20.00 6.54 |
|
|
1512 | Perl 16 25.75 12.62 |
1147 | Event 16 81.27 35.86 |
1513 | Event 16 81.27 35.86 |
1148 | Glib 16 32.63 15.48 |
1514 | Glib 16 32.63 15.48 |
1149 | Perl 16 24.62 162.37 |
|
|
1150 | POE 16 261.87 276.28 uses POE::Loop::Event |
1515 | POE 16 261.87 276.28 uses POE::Loop::Event |
1151 | |
1516 | |
1152 | =head3 Discussion |
1517 | =head3 Discussion |
1153 | |
1518 | |
1154 | The benchmark tries to test the performance of a typical small |
1519 | 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 |
1523 | speed most when you have lots of watchers, not when you only have a few of |
1159 | them). |
1524 | them). |
1160 | |
1525 | |
1161 | EV is again fastest. |
1526 | EV is again fastest. |
1162 | |
1527 | |
1163 | The C-based event loops Event and Glib come in second this time, as the |
1528 | Perl again comes second. It is noticeably faster than the C-based event |
1164 | overhead of running an iteration is much smaller in C than in Perl (little |
1529 | 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 |
1530 | 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 | |
1531 | |
1170 | POE also performs much better in this case, but is is still far behind the |
1532 | POE also performs much better in this case, but is is still far behind the |
1171 | others. |
1533 | others. |
1172 | |
1534 | |
1173 | =head3 Summary |
1535 | =head3 Summary |
… | |
… | |
1181 | |
1543 | |
1182 | |
1544 | |
1183 | =head1 FORK |
1545 | =head1 FORK |
1184 | |
1546 | |
1185 | Most event libraries are not fork-safe. The ones who are usually are |
1547 | 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. |
1548 | because they rely on inefficient but fork-safe C<select> or C<poll> |
|
|
1549 | calls. Only L<EV> is fully fork-aware. |
1187 | |
1550 | |
1188 | If you have to fork, you must either do so I<before> creating your first |
1551 | 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. |
1552 | watcher OR you must not use AnyEvent at all in the child. |
1190 | |
1553 | |
1191 | |
1554 | |
… | |
… | |
1203 | |
1566 | |
1204 | BEGIN { delete $ENV{PERL_ANYEVENT_MODEL} } |
1567 | BEGIN { delete $ENV{PERL_ANYEVENT_MODEL} } |
1205 | |
1568 | |
1206 | use AnyEvent; |
1569 | use AnyEvent; |
1207 | |
1570 | |
|
|
1571 | Similar considerations apply to $ENV{PERL_ANYEVENT_VERBOSE}, as that can |
|
|
1572 | be used to probe what backend is used and gain other information (which is |
|
|
1573 | probably even less useful to an attacker than PERL_ANYEVENT_MODEL). |
|
|
1574 | |
1208 | |
1575 | |
1209 | =head1 SEE ALSO |
1576 | =head1 SEE ALSO |
1210 | |
1577 | |
1211 | Event modules: L<Coro::EV>, L<EV>, L<EV::Glib>, L<Glib::EV>, |
1578 | Utility functions: L<AnyEvent::Util>. |
1212 | L<Coro::Event>, L<Event>, L<Glib::Event>, L<Glib>, L<Coro>, L<Tk>, |
1579 | |
|
|
1580 | Event modules: L<EV>, L<EV::Glib>, L<Glib::EV>, L<Event>, L<Glib::Event>, |
1213 | L<Event::Lib>, L<Qt>, L<POE>. |
1581 | L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>. |
1214 | |
1582 | |
1215 | Implementations: L<AnyEvent::Impl::CoroEV>, L<AnyEvent::Impl::EV>, |
1583 | Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>, |
1216 | L<AnyEvent::Impl::CoroEvent>, L<AnyEvent::Impl::Event>, L<AnyEvent::Impl::Glib>, |
1584 | 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>, |
1585 | L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>, |
1218 | L<AnyEvent::Impl::Qt>, L<AnyEvent::Impl::POE>. |
1586 | L<AnyEvent::Impl::POE>. |
1219 | |
1587 | |
|
|
1588 | Non-blocking file handles, sockets, TCP clients and |
|
|
1589 | servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>. |
|
|
1590 | |
|
|
1591 | Asynchronous DNS: L<AnyEvent::DNS>. |
|
|
1592 | |
|
|
1593 | Coroutine support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>, L<Coro::Event>, |
|
|
1594 | |
1220 | Nontrivial usage examples: L<Net::FCP>, L<Net::XMPP2>. |
1595 | Nontrivial usage examples: L<Net::FCP>, L<Net::XMPP2>, L<AnyEvent::DNS>. |
1221 | |
1596 | |
1222 | |
1597 | |
1223 | =head1 AUTHOR |
1598 | =head1 AUTHOR |
1224 | |
1599 | |
1225 | Marc Lehmann <schmorp@schmorp.de> |
1600 | Marc Lehmann <schmorp@schmorp.de> |