ViewVC Help
View File | Revision Log | Show Annotations | Download File
/cvs/AnyEvent/lib/AnyEvent.pm
(Generate patch)

Comparing AnyEvent/lib/AnyEvent.pm (file contents):
Revision 1.107 by root, Tue May 6 12:15:50 2008 UTC vs.
Revision 1.175 by root, Sun Jul 27 08:43:32 2008 UTC

1=head1 NAME 1=head1 NAME
2 2
3AnyEvent - provide framework for multiple event loops 3AnyEvent - provide framework for multiple event loops
4 4
5EV, Event, Coro::EV, Coro::Event, Glib, Tk, Perl, Event::Lib, Qt, POE - various supported event loops 5EV, 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
11 my $w = AnyEvent->io (fh => $fh, poll => "r|w", cb => sub { 11 my $w = AnyEvent->io (fh => $fh, poll => "r|w", cb => sub { ... });
12
13 my $w = AnyEvent->timer (after => $seconds, cb => sub { ... });
14 my $w = AnyEvent->timer (after => $seconds, interval => $seconds, cb => ...
15
16 print AnyEvent->now; # prints current event loop time
17 print AnyEvent->time; # think Time::HiRes::time or simply CORE::time.
18
19 my $w = AnyEvent->signal (signal => "TERM", cb => sub { ... });
20
21 my $w = AnyEvent->child (pid => $pid, cb => sub {
22 my ($pid, $status) = @_;
12 ... 23 ...
13 }); 24 });
14 25
15 my $w = AnyEvent->timer (after => $seconds, cb => sub {
16 ...
17 });
18
19 my $w = AnyEvent->condvar; # stores whether a condition was flagged 26 my $w = AnyEvent->condvar; # stores whether a condition was flagged
27 $w->send; # wake up current and all future recv's
20 $w->wait; # enters "main loop" till $condvar gets ->send 28 $w->recv; # enters "main loop" till $condvar gets ->send
21 $w->send; # wake up current and all future wait's 29 # use a condvar in callback mode:
30 $w->cb (sub { $_[0]->recv });
31
32=head1 INTRODUCTION/TUTORIAL
33
34This manpage is mainly a reference manual. If you are interested
35in a tutorial or some gentle introduction, have a look at the
36L<AnyEvent::Intro> manpage.
22 37
23=head1 WHY YOU SHOULD USE THIS MODULE (OR NOT) 38=head1 WHY YOU SHOULD USE THIS MODULE (OR NOT)
24 39
25Glib, POE, IO::Async, Event... CPAN offers event models by the dozen 40Glib, POE, IO::Async, Event... CPAN offers event models by the dozen
26nowadays. So what is different about AnyEvent? 41nowadays. So what is different about AnyEvent?
27 42
28Executive Summary: AnyEvent is I<compatible>, AnyEvent is I<free of 43Executive Summary: AnyEvent is I<compatible>, AnyEvent is I<free of
29policy> and AnyEvent is I<small and efficient>. 44policy> and AnyEvent is I<small and efficient>.
30 45
31First and foremost, I<AnyEvent is not an event model> itself, it only 46First and foremost, I<AnyEvent is not an event model> itself, it only
32interfaces to whatever event model the main program happens to use in a 47interfaces to whatever event model the main program happens to use, in a
33pragmatic way. For event models and certain classes of immortals alike, 48pragmatic way. For event models and certain classes of immortals alike,
34the statement "there can only be one" is a bitter reality: In general, 49the statement "there can only be one" is a bitter reality: In general,
35only one event loop can be active at the same time in a process. AnyEvent 50only one event loop can be active at the same time in a process. AnyEvent
36helps hiding the differences between those event loops. 51cannot change this, but it can hide the differences between those event
52loops.
37 53
38The goal of AnyEvent is to offer module authors the ability to do event 54The goal of AnyEvent is to offer module authors the ability to do event
39programming (waiting for I/O or timer events) without subscribing to a 55programming (waiting for I/O or timer events) without subscribing to a
40religion, a way of living, and most importantly: without forcing your 56religion, a way of living, and most importantly: without forcing your
41module users into the same thing by forcing them to use the same event 57module users into the same thing by forcing them to use the same event
42model you use. 58model you use.
43 59
44For modules like POE or IO::Async (which is a total misnomer as it is 60For modules like POE or IO::Async (which is a total misnomer as it is
45actually doing all I/O I<synchronously>...), using them in your module is 61actually doing all I/O I<synchronously>...), using them in your module is
46like joining a cult: After you joined, you are dependent on them and you 62like joining a cult: After you joined, you are dependent on them and you
47cannot use anything else, as it is simply incompatible to everything that 63cannot use anything else, as they are simply incompatible to everything
48isn't itself. What's worse, all the potential users of your module are 64that isn't them. What's worse, all the potential users of your
49I<also> forced to use the same event loop you use. 65module are I<also> forced to use the same event loop you use.
50 66
51AnyEvent is different: AnyEvent + POE works fine. AnyEvent + Glib works 67AnyEvent is different: AnyEvent + POE works fine. AnyEvent + Glib works
52fine. AnyEvent + Tk works fine etc. etc. but none of these work together 68fine. AnyEvent + Tk works fine etc. etc. but none of these work together
53with the rest: POE + IO::Async? no go. Tk + Event? no go. Again: if 69with the rest: POE + IO::Async? No go. Tk + Event? No go. Again: if
54your module uses one of those, every user of your module has to use it, 70your module uses one of those, every user of your module has to use it,
55too. But if your module uses AnyEvent, it works transparently with all 71too. But if your module uses AnyEvent, it works transparently with all
56event models it supports (including stuff like POE and IO::Async, as long 72event models it supports (including stuff like IO::Async, as long as those
57as those use one of the supported event loops. It is trivial to add new 73use one of the supported event loops. It is trivial to add new event loops
58event loops to AnyEvent, too, so it is future-proof). 74to AnyEvent, too, so it is future-proof).
59 75
60In addition to being free of having to use I<the one and only true event 76In addition to being free of having to use I<the one and only true event
61model>, AnyEvent also is free of bloat and policy: with POE or similar 77model>, AnyEvent also is free of bloat and policy: with POE or similar
62modules, you get an enourmous amount of code and strict rules you have to 78modules, you get an enormous amount of code and strict rules you have to
63follow. AnyEvent, on the other hand, is lean and up to the point, by only 79follow. AnyEvent, on the other hand, is lean and up to the point, by only
64offering the functionality that is necessary, in as thin as a wrapper as 80offering the functionality that is necessary, in as thin as a wrapper as
65technically possible. 81technically possible.
66 82
83Of course, AnyEvent comes with a big (and fully optional!) toolbox
84of useful functionality, such as an asynchronous DNS resolver, 100%
85non-blocking connects (even with TLS/SSL, IPv6 and on broken platforms
86such as Windows) and lots of real-world knowledge and workarounds for
87platform bugs and differences.
88
67Of course, if you want lots of policy (this can arguably be somewhat 89Now, if you I<do want> lots of policy (this can arguably be somewhat
68useful) and you want to force your users to use the one and only event 90useful) and you want to force your users to use the one and only event
69model, you should I<not> use this module. 91model, you should I<not> use this module.
70 92
71=head1 DESCRIPTION 93=head1 DESCRIPTION
72 94
78The interface itself is vaguely similar, but not identical to the L<Event> 100The interface itself is vaguely similar, but not identical to the L<Event>
79module. 101module.
80 102
81During the first call of any watcher-creation method, the module tries 103During the first call of any watcher-creation method, the module tries
82to detect the currently loaded event loop by probing whether one of the 104to detect the currently loaded event loop by probing whether one of the
83following modules is already loaded: L<Coro::EV>, L<Coro::Event>, L<EV>, 105following modules is already loaded: L<EV>,
84L<Event>, L<Glib>, L<AnyEvent::Impl::Perl>, L<Tk>, L<Event::Lib>, L<Qt>, 106L<Event>, L<Glib>, L<AnyEvent::Impl::Perl>, L<Tk>, L<Event::Lib>, L<Qt>,
85L<POE>. The first one found is used. If none are found, the module tries 107L<POE>. The first one found is used. If none are found, the module tries
86to load these modules (excluding Tk, Event::Lib, Qt and POE as the pure perl 108to load these modules (excluding Tk, Event::Lib, Qt and POE as the pure perl
87adaptor should always succeed) in the order given. The first one that can 109adaptor should always succeed) in the order given. The first one that can
88be successfully loaded will be used. If, after this, still none could be 110be successfully loaded will be used. If, after this, still none could be
102starts using it, all bets are off. Maybe you should tell their authors to 124starts using it, all bets are off. Maybe you should tell their authors to
103use AnyEvent so their modules work together with others seamlessly... 125use AnyEvent so their modules work together with others seamlessly...
104 126
105The pure-perl implementation of AnyEvent is called 127The pure-perl implementation of AnyEvent is called
106C<AnyEvent::Impl::Perl>. Like other event modules you can load it 128C<AnyEvent::Impl::Perl>. Like other event modules you can load it
107explicitly. 129explicitly and enjoy the high availability of that event loop :)
108 130
109=head1 WATCHERS 131=head1 WATCHERS
110 132
111AnyEvent has the central concept of a I<watcher>, which is an object that 133AnyEvent has the central concept of a I<watcher>, which is an object that
112stores relevant data for each kind of event you are waiting for, such as 134stores relevant data for each kind of event you are waiting for, such as
113the callback to call, the filehandle to watch, etc. 135the callback to call, the file handle to watch, etc.
114 136
115These watchers are normal Perl objects with normal Perl lifetime. After 137These watchers are normal Perl objects with normal Perl lifetime. After
116creating a watcher it will immediately "watch" for events and invoke the 138creating a watcher it will immediately "watch" for events and invoke the
117callback when the event occurs (of course, only when the event model 139callback when the event occurs (of course, only when the event model
118is in control). 140is in control).
126Many watchers either are used with "recursion" (repeating timers for 148Many watchers either are used with "recursion" (repeating timers for
127example), or need to refer to their watcher object in other ways. 149example), or need to refer to their watcher object in other ways.
128 150
129An any way to achieve that is this pattern: 151An any way to achieve that is this pattern:
130 152
131 my $w; $w = AnyEvent->type (arg => value ..., cb => sub { 153 my $w; $w = AnyEvent->type (arg => value ..., cb => sub {
132 # you can use $w here, for example to undef it 154 # you can use $w here, for example to undef it
133 undef $w; 155 undef $w;
134 }); 156 });
135 157
136Note that C<my $w; $w => combination. This is necessary because in Perl, 158Note that C<my $w; $w => combination. This is necessary because in Perl,
137my variables are only visible after the statement in which they are 159my variables are only visible after the statement in which they are
138declared. 160declared.
139 161
140=head2 I/O WATCHERS 162=head2 I/O WATCHERS
141 163
142You can create an I/O watcher by calling the C<< AnyEvent->io >> method 164You can create an I/O watcher by calling the C<< AnyEvent->io >> method
143with the following mandatory key-value pairs as arguments: 165with the following mandatory key-value pairs as arguments:
144 166
145C<fh> the Perl I<file handle> (I<not> file descriptor) to watch 167C<fh> the Perl I<file handle> (I<not> file descriptor) to watch for events
146for events. C<poll> must be a string that is either C<r> or C<w>, 168(AnyEvent might or might not keep a reference to this file handle). C<poll>
147which creates a watcher waiting for "r"eadable or "w"ritable events, 169must be a string that is either C<r> or C<w>, which creates a watcher
148respectively. C<cb> is the callback to invoke each time the file handle 170waiting for "r"eadable or "w"ritable events, respectively. C<cb> is the
149becomes ready. 171callback to invoke each time the file handle becomes ready.
150 172
151Although the callback might get passed parameters, their value and 173Although the callback might get passed parameters, their value and
152presence is undefined and you cannot rely on them. Portable AnyEvent 174presence is undefined and you cannot rely on them. Portable AnyEvent
153callbacks cannot use arguments passed to I/O watcher callbacks. 175callbacks cannot use arguments passed to I/O watcher callbacks.
154 176
158 180
159Some event loops issue spurious readyness notifications, so you should 181Some event loops issue spurious readyness notifications, so you should
160always use non-blocking calls when reading/writing from/to your file 182always use non-blocking calls when reading/writing from/to your file
161handles. 183handles.
162 184
163Example:
164
165 # wait for readability of STDIN, then read a line and disable the watcher 185Example: wait for readability of STDIN, then read a line and disable the
186watcher.
187
166 my $w; $w = AnyEvent->io (fh => \*STDIN, poll => 'r', cb => sub { 188 my $w; $w = AnyEvent->io (fh => \*STDIN, poll => 'r', cb => sub {
167 chomp (my $input = <STDIN>); 189 chomp (my $input = <STDIN>);
168 warn "read: $input\n"; 190 warn "read: $input\n";
169 undef $w; 191 undef $w;
170 }); 192 });
180 202
181Although the callback might get passed parameters, their value and 203Although the callback might get passed parameters, their value and
182presence is undefined and you cannot rely on them. Portable AnyEvent 204presence is undefined and you cannot rely on them. Portable AnyEvent
183callbacks cannot use arguments passed to time watcher callbacks. 205callbacks cannot use arguments passed to time watcher callbacks.
184 206
185The timer callback will be invoked at most once: if you want a repeating 207The callback will normally be invoked once only. If you specify another
186timer you have to create a new watcher (this is a limitation by both Tk 208parameter, C<interval>, as a strictly positive number (> 0), then the
187and Glib). 209callback will be invoked regularly at that interval (in fractional
210seconds) after the first invocation. If C<interval> is specified with a
211false value, then it is treated as if it were missing.
188 212
189Example: 213The callback will be rescheduled before invoking the callback, but no
214attempt is done to avoid timer drift in most backends, so the interval is
215only approximate.
190 216
191 # fire an event after 7.7 seconds 217Example: fire an event after 7.7 seconds.
218
192 my $w = AnyEvent->timer (after => 7.7, cb => sub { 219 my $w = AnyEvent->timer (after => 7.7, cb => sub {
193 warn "timeout\n"; 220 warn "timeout\n";
194 }); 221 });
195 222
196 # to cancel the timer: 223 # to cancel the timer:
197 undef $w; 224 undef $w;
198 225
199Example 2:
200
201 # fire an event after 0.5 seconds, then roughly every second 226Example 2: fire an event after 0.5 seconds, then roughly every second.
202 my $w;
203 227
204 my $cb = sub {
205 # cancel the old timer while creating a new one
206 $w = AnyEvent->timer (after => 1, cb => $cb); 228 my $w = AnyEvent->timer (after => 0.5, interval => 1, cb => sub {
229 warn "timeout\n";
207 }; 230 };
208
209 # start the "loop" by creating the first watcher
210 $w = AnyEvent->timer (after => 0.5, cb => $cb);
211 231
212=head3 TIMING ISSUES 232=head3 TIMING ISSUES
213 233
214There are two ways to handle timers: based on real time (relative, "fire 234There are two ways to handle timers: based on real time (relative, "fire
215in 10 seconds") and based on wallclock time (absolute, "fire at 12 235in 10 seconds") and based on wallclock time (absolute, "fire at 12
227timers. 247timers.
228 248
229AnyEvent always prefers relative timers, if available, matching the 249AnyEvent always prefers relative timers, if available, matching the
230AnyEvent API. 250AnyEvent API.
231 251
252AnyEvent has two additional methods that return the "current time":
253
254=over 4
255
256=item AnyEvent->time
257
258This returns the "current wallclock time" as a fractional number of
259seconds since the Epoch (the same thing as C<time> or C<Time::HiRes::time>
260return, and the result is guaranteed to be compatible with those).
261
262It progresses independently of any event loop processing, i.e. each call
263will check the system clock, which usually gets updated frequently.
264
265=item AnyEvent->now
266
267This also returns the "current wallclock time", but unlike C<time>, above,
268this value might change only once per event loop iteration, depending on
269the event loop (most return the same time as C<time>, above). This is the
270time that AnyEvent's timers get scheduled against.
271
272I<In almost all cases (in all cases if you don't care), this is the
273function to call when you want to know the current time.>
274
275This function is also often faster then C<< AnyEvent->time >>, and
276thus the preferred method if you want some timestamp (for example,
277L<AnyEvent::Handle> uses this to update it's activity timeouts).
278
279The rest of this section is only of relevance if you try to be very exact
280with your timing, you can skip it without bad conscience.
281
282For a practical example of when these times differ, consider L<Event::Lib>
283and L<EV> and the following set-up:
284
285The event loop is running and has just invoked one of your callback at
286time=500 (assume no other callbacks delay processing). In your callback,
287you wait a second by executing C<sleep 1> (blocking the process for a
288second) and then (at time=501) you create a relative timer that fires
289after three seconds.
290
291With L<Event::Lib>, C<< AnyEvent->time >> and C<< AnyEvent->now >> will
292both return C<501>, because that is the current time, and the timer will
293be scheduled to fire at time=504 (C<501> + C<3>).
294
295With L<EV>, C<< AnyEvent->time >> returns C<501> (as that is the current
296time), but C<< AnyEvent->now >> returns C<500>, as that is the time the
297last event processing phase started. With L<EV>, your timer gets scheduled
298to run at time=503 (C<500> + C<3>).
299
300In one sense, L<Event::Lib> is more exact, as it uses the current time
301regardless of any delays introduced by event processing. However, most
302callbacks do not expect large delays in processing, so this causes a
303higher drift (and a lot more system calls to get the current time).
304
305In another sense, L<EV> is more exact, as your timer will be scheduled at
306the same time, regardless of how long event processing actually took.
307
308In either case, if you care (and in most cases, you don't), then you
309can get whatever behaviour you want with any event loop, by taking the
310difference between C<< AnyEvent->time >> and C<< AnyEvent->now >> into
311account.
312
313=back
314
232=head2 SIGNAL WATCHERS 315=head2 SIGNAL WATCHERS
233 316
234You can watch for signals using a signal watcher, C<signal> is the signal 317You can watch for signals using a signal watcher, C<signal> is the signal
235I<name> without any C<SIG> prefix, C<cb> is the Perl callback to 318I<name> in uppercase and without any C<SIG> prefix, C<cb> is the Perl
236be invoked whenever a signal occurs. 319callback to be invoked whenever a signal occurs.
237 320
238Although the callback might get passed parameters, their value and 321Although the callback might get passed parameters, their value and
239presence is undefined and you cannot rely on them. Portable AnyEvent 322presence is undefined and you cannot rely on them. Portable AnyEvent
240callbacks cannot use arguments passed to signal watcher callbacks. 323callbacks cannot use arguments passed to signal watcher callbacks.
241 324
242Multiple signal occurances can be clumped together into one callback 325Multiple signal occurrences can be clumped together into one callback
243invocation, and callback invocation will be synchronous. synchronous means 326invocation, and callback invocation will be synchronous. Synchronous means
244that it might take a while until the signal gets handled by the process, 327that it might take a while until the signal gets handled by the process,
245but it is guarenteed not to interrupt any other callbacks. 328but it is guaranteed not to interrupt any other callbacks.
246 329
247The main advantage of using these watchers is that you can share a signal 330The main advantage of using these watchers is that you can share a signal
248between multiple watchers. 331between multiple watchers.
249 332
250This watcher might use C<%SIG>, so programs overwriting those signals 333This watcher might use C<%SIG>, so programs overwriting those signals
277AnyEvent program, you I<have> to create at least one watcher before you 360AnyEvent program, you I<have> to create at least one watcher before you
278C<fork> the child (alternatively, you can call C<AnyEvent::detect>). 361C<fork> the child (alternatively, you can call C<AnyEvent::detect>).
279 362
280Example: fork a process and wait for it 363Example: fork a process and wait for it
281 364
282 my $done = AnyEvent->condvar; 365 my $done = AnyEvent->condvar;
283 366
284 AnyEvent::detect; # force event module to be initialised
285
286 my $pid = fork or exit 5; 367 my $pid = fork or exit 5;
287 368
288 my $w = AnyEvent->child ( 369 my $w = AnyEvent->child (
289 pid => $pid, 370 pid => $pid,
290 cb => sub { 371 cb => sub {
291 my ($pid, $status) = @_; 372 my ($pid, $status) = @_;
292 warn "pid $pid exited with status $status"; 373 warn "pid $pid exited with status $status";
293 $done->send; 374 $done->send;
294 }, 375 },
295 ); 376 );
296 377
297 # do something else, then wait for process exit 378 # do something else, then wait for process exit
298 $done->wait; 379 $done->recv;
299 380
300=head2 CONDITION VARIABLES 381=head2 CONDITION VARIABLES
301 382
302If you are familiar with some event loops you will know that all of them 383If you are familiar with some event loops you will know that all of them
303require you to run some blocking "loop", "run" or similar function that 384require you to run some blocking "loop", "run" or similar function that
309The instrument to do that is called a "condition variable", so called 390The instrument to do that is called a "condition variable", so called
310because they represent a condition that must become true. 391because they represent a condition that must become true.
311 392
312Condition variables can be created by calling the C<< AnyEvent->condvar 393Condition variables can be created by calling the C<< AnyEvent->condvar
313>> method, usually without arguments. The only argument pair allowed is 394>> method, usually without arguments. The only argument pair allowed is
395
314C<cb>, which specifies a callback to be called when the condition variable 396C<cb>, which specifies a callback to be called when the condition variable
315becomes true. 397becomes true, with the condition variable as the first argument (but not
398the results).
316 399
317After creation, the conditon variable is "false" until it becomes "true" 400After creation, the condition variable is "false" until it becomes "true"
318by calling the C<send> method. 401by calling the C<send> method (or calling the condition variable as if it
402were a callback, read about the caveats in the description for the C<<
403->send >> method).
319 404
320Condition variables are similar to callbacks, except that you can 405Condition variables are similar to callbacks, except that you can
321optionally wait for them. They can also be called merge points - points 406optionally wait for them. They can also be called merge points - points
322in time where multiple outstandign events have been processed. And yet 407in time where multiple outstanding events have been processed. And yet
323another way to call them is transations - each condition variable can be 408another way to call them is transactions - each condition variable can be
324used to represent a transaction, which finishes at some point and delivers 409used to represent a transaction, which finishes at some point and delivers
325a result. 410a result.
326 411
327Condition variables are very useful to signal that something has finished, 412Condition variables are very useful to signal that something has finished,
328for example, if you write a module that does asynchronous http requests, 413for example, if you write a module that does asynchronous http requests,
329then a condition variable would be the ideal candidate to signal the 414then a condition variable would be the ideal candidate to signal the
330availability of results. The user can either act when the callback is 415availability of results. The user can either act when the callback is
331called or can synchronously C<< ->wait >> for the results. 416called or can synchronously C<< ->recv >> for the results.
332 417
333You can also use them to simulate traditional event loops - for example, 418You can also use them to simulate traditional event loops - for example,
334you can block your main program until an event occurs - for example, you 419you can block your main program until an event occurs - for example, you
335could C<< ->wait >> in your main program until the user clicks the Quit 420could C<< ->recv >> in your main program until the user clicks the Quit
336button of your app, which would C<< ->send >> the "quit" event. 421button of your app, which would C<< ->send >> the "quit" event.
337 422
338Note that condition variables recurse into the event loop - if you have 423Note that condition variables recurse into the event loop - if you have
339two pieces of code that call C<< ->wait >> in a round-robbin fashion, you 424two pieces of code that call C<< ->recv >> in a round-robin fashion, you
340lose. Therefore, condition variables are good to export to your caller, but 425lose. Therefore, condition variables are good to export to your caller, but
341you should avoid making a blocking wait yourself, at least in callbacks, 426you should avoid making a blocking wait yourself, at least in callbacks,
342as this asks for trouble. 427as this asks for trouble.
343 428
344Condition variables are represented by hash refs in perl, and the keys 429Condition variables are represented by hash refs in perl, and the keys
349 434
350There are two "sides" to a condition variable - the "producer side" which 435There are two "sides" to a condition variable - the "producer side" which
351eventually calls C<< -> send >>, and the "consumer side", which waits 436eventually calls C<< -> send >>, and the "consumer side", which waits
352for the send to occur. 437for the send to occur.
353 438
354Example: 439Example: wait for a timer.
355 440
356 # wait till the result is ready 441 # wait till the result is ready
357 my $result_ready = AnyEvent->condvar; 442 my $result_ready = AnyEvent->condvar;
358 443
359 # do something such as adding a timer 444 # do something such as adding a timer
365 cb => sub { $result_ready->send }, 450 cb => sub { $result_ready->send },
366 ); 451 );
367 452
368 # this "blocks" (while handling events) till the callback 453 # this "blocks" (while handling events) till the callback
369 # calls send 454 # calls send
370 $result_ready->wait; 455 $result_ready->recv;
456
457Example: wait for a timer, but take advantage of the fact that
458condition variables are also code references.
459
460 my $done = AnyEvent->condvar;
461 my $delay = AnyEvent->timer (after => 5, cb => $done);
462 $done->recv;
463
464Example: Imagine an API that returns a condvar and doesn't support
465callbacks. This is how you make a synchronous call, for example from
466the main program:
467
468 use AnyEvent::CouchDB;
469
470 ...
471
472 my @info = $couchdb->info->recv;
473
474And this is how you would just ste a callback to be called whenever the
475results are available:
476
477 $couchdb->info->cb (sub {
478 my @info = $_[0]->recv;
479 });
371 480
372=head3 METHODS FOR PRODUCERS 481=head3 METHODS FOR PRODUCERS
373 482
374These methods should only be used by the producing side, i.e. the 483These methods should only be used by the producing side, i.e. the
375code/module that eventually sends the signal. Note that it is also 484code/module that eventually sends the signal. Note that it is also
378 487
379=over 4 488=over 4
380 489
381=item $cv->send (...) 490=item $cv->send (...)
382 491
383Flag the condition as ready - a running C<< ->wait >> and all further 492Flag the condition as ready - a running C<< ->recv >> and all further
384calls to C<wait> will (eventually) return after this method has been 493calls to C<recv> will (eventually) return after this method has been
385called. If nobody is waiting the send will be remembered. 494called. If nobody is waiting the send will be remembered.
386 495
387If a callback has been set on the condition variable, it is called 496If a callback has been set on the condition variable, it is called
388immediately from within send. 497immediately from within send.
389 498
390Any arguments passed to the C<send> call will be returned by all 499Any arguments passed to the C<send> call will be returned by all
391future C<< ->wait >> calls. 500future C<< ->recv >> calls.
501
502Condition variables are overloaded so one can call them directly
503(as a code reference). Calling them directly is the same as calling
504C<send>. Note, however, that many C-based event loops do not handle
505overloading, so as tempting as it may be, passing a condition variable
506instead of a callback does not work. Both the pure perl and EV loops
507support overloading, however, as well as all functions that use perl to
508invoke a callback (as in L<AnyEvent::Socket> and L<AnyEvent::DNS> for
509example).
392 510
393=item $cv->croak ($error) 511=item $cv->croak ($error)
394 512
395Similar to send, but causes all call's wait C<< ->wait >> to invoke 513Similar to send, but causes all call's to C<< ->recv >> to invoke
396C<Carp::croak> with the given error message/object/scalar. 514C<Carp::croak> with the given error message/object/scalar.
397 515
398This can be used to signal any errors to the condition variable 516This can be used to signal any errors to the condition variable
399user/consumer. 517user/consumer.
400 518
401=item $cv->begin ([group callback]) 519=item $cv->begin ([group callback])
402 520
403=item $cv->end 521=item $cv->end
522
523These two methods are EXPERIMENTAL and MIGHT CHANGE.
404 524
405These two methods can be used to combine many transactions/events into 525These two methods can be used to combine many transactions/events into
406one. For example, a function that pings many hosts in parallel might want 526one. For example, a function that pings many hosts in parallel might want
407to use a condition variable for the whole process. 527to use a condition variable for the whole process.
408 528
443doesn't execute once). 563doesn't execute once).
444 564
445This is the general pattern when you "fan out" into multiple subrequests: 565This is the general pattern when you "fan out" into multiple subrequests:
446use an outer C<begin>/C<end> pair to set the callback and ensure C<end> 566use an outer C<begin>/C<end> pair to set the callback and ensure C<end>
447is called at least once, and then, for each subrequest you start, call 567is called at least once, and then, for each subrequest you start, call
448C<begin> and for eahc subrequest you finish, call C<end>. 568C<begin> and for each subrequest you finish, call C<end>.
449 569
450=back 570=back
451 571
452=head3 METHODS FOR CONSUMERS 572=head3 METHODS FOR CONSUMERS
453 573
454These methods should only be used by the consuming side, i.e. the 574These methods should only be used by the consuming side, i.e. the
455code awaits the condition. 575code awaits the condition.
456 576
457=over 4 577=over 4
458 578
459=item $cv->wait 579=item $cv->recv
460 580
461Wait (blocking if necessary) until the C<< ->send >> or C<< ->croak 581Wait (blocking if necessary) until the C<< ->send >> or C<< ->croak
462>> methods have been called on c<$cv>, while servicing other watchers 582>> methods have been called on c<$cv>, while servicing other watchers
463normally. 583normally.
464 584
475(programs might want to do that to stay interactive), so I<if you are 595(programs might want to do that to stay interactive), so I<if you are
476using this from a module, never require a blocking wait>, but let the 596using this from a module, never require a blocking wait>, but let the
477caller decide whether the call will block or not (for example, by coupling 597caller decide whether the call will block or not (for example, by coupling
478condition variables with some kind of request results and supporting 598condition variables with some kind of request results and supporting
479callbacks so the caller knows that getting the result will not block, 599callbacks so the caller knows that getting the result will not block,
480while still suppporting blocking waits if the caller so desires). 600while still supporting blocking waits if the caller so desires).
481 601
482Another reason I<never> to C<< ->wait >> in a module is that you cannot 602Another reason I<never> to C<< ->recv >> in a module is that you cannot
483sensibly have two C<< ->wait >>'s in parallel, as that would require 603sensibly have two C<< ->recv >>'s in parallel, as that would require
484multiple interpreters or coroutines/threads, none of which C<AnyEvent> 604multiple interpreters or coroutines/threads, none of which C<AnyEvent>
485can supply (the coroutine-aware backends L<AnyEvent::Impl::CoroEV> and 605can supply.
486L<AnyEvent::Impl::CoroEvent> explicitly support concurrent C<< ->wait >>'s
487from different coroutines, however).
488 606
607The L<Coro> module, however, I<can> and I<does> supply coroutines and, in
608fact, L<Coro::AnyEvent> replaces AnyEvent's condvars by coroutine-safe
609versions and also integrates coroutines into AnyEvent, making blocking
610C<< ->recv >> calls perfectly safe as long as they are done from another
611coroutine (one that doesn't run the event loop).
612
489You can ensure that C<< -wait >> never blocks by setting a callback and 613You can ensure that C<< -recv >> never blocks by setting a callback and
490only calling C<< ->wait >> from within that callback (or at a later 614only calling C<< ->recv >> from within that callback (or at a later
491time). This will work even when the event loop does not support blocking 615time). This will work even when the event loop does not support blocking
492waits otherwise. 616waits otherwise.
493 617
494=item $bool = $cv->ready 618=item $bool = $cv->ready
495 619
496Returns true when the condition is "true", i.e. whether C<send> or 620Returns true when the condition is "true", i.e. whether C<send> or
497C<croak> have been called. 621C<croak> have been called.
498 622
499=item $cb = $cv->cb ([new callback]) 623=item $cb = $cv->cb ($cb->($cv))
500 624
501This is a mutator function that returns the callback set and optionally 625This is a mutator function that returns the callback set and optionally
502replaces it before doing so. 626replaces it before doing so.
503 627
504The callback will be called when the condition becomes "true", i.e. when 628The callback will be called when the condition becomes "true", i.e. when
505C<send> or C<croak> are called. Calling C<wait> inside the callback 629C<send> or C<croak> are called, with the only argument being the condition
506or at any later time is guaranteed not to block. 630variable itself. Calling C<recv> inside the callback or at any later time
631is guaranteed not to block.
507 632
508=back 633=back
509 634
510=head1 GLOBAL VARIABLES AND FUNCTIONS 635=head1 GLOBAL VARIABLES AND FUNCTIONS
511 636
519C<AnyEvent::Impl:xxx> modules, but can be any other class in the case 644C<AnyEvent::Impl:xxx> modules, but can be any other class in the case
520AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode>). 645AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode>).
521 646
522The known classes so far are: 647The known classes so far are:
523 648
524 AnyEvent::Impl::CoroEV based on Coro::EV, best choice.
525 AnyEvent::Impl::CoroEvent based on Coro::Event, second best choice.
526 AnyEvent::Impl::EV based on EV (an interface to libev, best choice). 649 AnyEvent::Impl::EV based on EV (an interface to libev, best choice).
527 AnyEvent::Impl::Event based on Event, second best choice. 650 AnyEvent::Impl::Event based on Event, second best choice.
528 AnyEvent::Impl::Perl pure-perl implementation, fast and portable. 651 AnyEvent::Impl::Perl pure-perl implementation, fast and portable.
529 AnyEvent::Impl::Glib based on Glib, third-best choice. 652 AnyEvent::Impl::Glib based on Glib, third-best choice.
530 AnyEvent::Impl::Tk based on Tk, very bad choice. 653 AnyEvent::Impl::Tk based on Tk, very bad choice.
547Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model 670Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model
548if necessary. You should only call this function right before you would 671if necessary. You should only call this function right before you would
549have created an AnyEvent watcher anyway, that is, as late as possible at 672have created an AnyEvent watcher anyway, that is, as late as possible at
550runtime. 673runtime.
551 674
675=item $guard = AnyEvent::post_detect { BLOCK }
676
677Arranges for the code block to be executed as soon as the event model is
678autodetected (or immediately if this has already happened).
679
680If called in scalar or list context, then it creates and returns an object
681that automatically removes the callback again when it is destroyed. See
682L<Coro::BDB> for a case where this is useful.
683
684=item @AnyEvent::post_detect
685
686If there are any code references in this array (you can C<push> to it
687before or after loading AnyEvent), then they will called directly after
688the event loop has been chosen.
689
690You should check C<$AnyEvent::MODEL> before adding to this array, though:
691if it contains a true value then the event loop has already been detected,
692and the array will be ignored.
693
694Best use C<AnyEvent::post_detect { BLOCK }> instead.
695
552=back 696=back
553 697
554=head1 WHAT TO DO IN A MODULE 698=head1 WHAT TO DO IN A MODULE
555 699
556As a module author, you should C<use AnyEvent> and call AnyEvent methods 700As a module author, you should C<use AnyEvent> and call AnyEvent methods
559Be careful when you create watchers in the module body - AnyEvent will 703Be careful when you create watchers in the module body - AnyEvent will
560decide which event module to use as soon as the first method is called, so 704decide which event module to use as soon as the first method is called, so
561by calling AnyEvent in your module body you force the user of your module 705by calling AnyEvent in your module body you force the user of your module
562to load the event module first. 706to load the event module first.
563 707
564Never call C<< ->wait >> on a condition variable unless you I<know> that 708Never call C<< ->recv >> on a condition variable unless you I<know> that
565the C<< ->send >> method has been called on it already. This is 709the C<< ->send >> method has been called on it already. This is
566because it will stall the whole program, and the whole point of using 710because it will stall the whole program, and the whole point of using
567events is to stay interactive. 711events is to stay interactive.
568 712
569It is fine, however, to call C<< ->wait >> when the user of your module 713It is fine, however, to call C<< ->recv >> when the user of your module
570requests it (i.e. if you create a http request object ad have a method 714requests it (i.e. if you create a http request object ad have a method
571called C<results> that returns the results, it should call C<< ->wait >> 715called C<results> that returns the results, it should call C<< ->recv >>
572freely, as the user of your module knows what she is doing. always). 716freely, as the user of your module knows what she is doing. always).
573 717
574=head1 WHAT TO DO IN THE MAIN PROGRAM 718=head1 WHAT TO DO IN THE MAIN PROGRAM
575 719
576There will always be a single main program - the only place that should 720There will always be a single main program - the only place that should
578 722
579If it doesn't care, it can just "use AnyEvent" and use it itself, or not 723If it doesn't care, it can just "use AnyEvent" and use it itself, or not
580do anything special (it does not need to be event-based) and let AnyEvent 724do anything special (it does not need to be event-based) and let AnyEvent
581decide which implementation to chose if some module relies on it. 725decide which implementation to chose if some module relies on it.
582 726
583If the main program relies on a specific event model. For example, in 727If the main program relies on a specific event model - for example, in
584Gtk2 programs you have to rely on the Glib module. You should load the 728Gtk2 programs you have to rely on the Glib module - you should load the
585event module before loading AnyEvent or any module that uses it: generally 729event module before loading AnyEvent or any module that uses it: generally
586speaking, you should load it as early as possible. The reason is that 730speaking, you should load it as early as possible. The reason is that
587modules might create watchers when they are loaded, and AnyEvent will 731modules might create watchers when they are loaded, and AnyEvent will
588decide on the event model to use as soon as it creates watchers, and it 732decide on the event model to use as soon as it creates watchers, and it
589might chose the wrong one unless you load the correct one yourself. 733might chose the wrong one unless you load the correct one yourself.
590 734
591You can chose to use a rather inefficient pure-perl implementation by 735You can chose to use a pure-perl implementation by loading the
592loading the C<AnyEvent::Impl::Perl> module, which gives you similar 736C<AnyEvent::Impl::Perl> module, which gives you similar behaviour
593behaviour everywhere, but letting AnyEvent chose is generally better. 737everywhere, but letting AnyEvent chose the model is generally better.
738
739=head2 MAINLOOP EMULATION
740
741Sometimes (often for short test scripts, or even standalone programs who
742only want to use AnyEvent), you do not want to run a specific event loop.
743
744In that case, you can use a condition variable like this:
745
746 AnyEvent->condvar->recv;
747
748This has the effect of entering the event loop and looping forever.
749
750Note that usually your program has some exit condition, in which case
751it is better to use the "traditional" approach of storing a condition
752variable somewhere, waiting for it, and sending it when the program should
753exit cleanly.
754
594 755
595=head1 OTHER MODULES 756=head1 OTHER MODULES
596 757
597The following is a non-exhaustive list of additional modules that use 758The following is a non-exhaustive list of additional modules that use
598AnyEvent and can therefore be mixed easily with other AnyEvent modules 759AnyEvent and can therefore be mixed easily with other AnyEvent modules
604=item L<AnyEvent::Util> 765=item L<AnyEvent::Util>
605 766
606Contains various utility functions that replace often-used but blocking 767Contains various utility functions that replace often-used but blocking
607functions such as C<inet_aton> by event-/callback-based versions. 768functions such as C<inet_aton> by event-/callback-based versions.
608 769
770=item L<AnyEvent::Socket>
771
772Provides various utility functions for (internet protocol) sockets,
773addresses and name resolution. Also functions to create non-blocking tcp
774connections or tcp servers, with IPv6 and SRV record support and more.
775
609=item L<AnyEvent::Handle> 776=item L<AnyEvent::Handle>
610 777
611Provide read and write buffers and manages watchers for reads and writes. 778Provide read and write buffers, manages watchers for reads and writes,
779supports raw and formatted I/O, I/O queued and fully transparent and
780non-blocking SSL/TLS.
612 781
613=item L<AnyEvent::Socket> 782=item L<AnyEvent::DNS>
614 783
615Provides a means to do non-blocking connects, accepts etc. 784Provides rich asynchronous DNS resolver capabilities.
785
786=item L<AnyEvent::HTTP>
787
788A simple-to-use HTTP library that is capable of making a lot of concurrent
789HTTP requests.
616 790
617=item L<AnyEvent::HTTPD> 791=item L<AnyEvent::HTTPD>
618 792
619Provides a simple web application server framework. 793Provides a simple web application server framework.
620 794
621=item L<AnyEvent::DNS>
622
623Provides asynchronous DNS resolver capabilities, beyond what
624L<AnyEvent::Util> offers.
625
626=item L<AnyEvent::FastPing> 795=item L<AnyEvent::FastPing>
627 796
628The fastest ping in the west. 797The fastest ping in the west.
798
799=item L<AnyEvent::DBI>
800
801Executes L<DBI> requests asynchronously in a proxy process.
802
803=item L<AnyEvent::AIO>
804
805Truly asynchronous I/O, should be in the toolbox of every event
806programmer. AnyEvent::AIO transparently fuses L<IO::AIO> and AnyEvent
807together.
808
809=item L<AnyEvent::BDB>
810
811Truly asynchronous Berkeley DB access. AnyEvent::BDB transparently fuses
812L<BDB> and AnyEvent together.
813
814=item L<AnyEvent::GPSD>
815
816A non-blocking interface to gpsd, a daemon delivering GPS information.
817
818=item L<AnyEvent::IGS>
819
820A non-blocking interface to the Internet Go Server protocol (used by
821L<App::IGS>).
629 822
630=item L<Net::IRC3> 823=item L<Net::IRC3>
631 824
632AnyEvent based IRC client module family. 825AnyEvent based IRC client module family.
633 826
644 837
645High level API for event-based execution flow control. 838High level API for event-based execution flow control.
646 839
647=item L<Coro> 840=item L<Coro>
648 841
649Has special support for AnyEvent. 842Has special support for AnyEvent via L<Coro::AnyEvent>.
650 843
651=item L<IO::Lambda> 844=item L<IO::Lambda>
652 845
653The lambda approach to I/O - don't ask, look there. Can use AnyEvent. 846The lambda approach to I/O - don't ask, look there. Can use AnyEvent.
654
655=item L<IO::AIO>
656
657Truly asynchronous I/O, should be in the toolbox of every event
658programmer. Can be trivially made to use AnyEvent.
659
660=item L<BDB>
661
662Truly asynchronous Berkeley DB access. Can be trivially made to use
663AnyEvent.
664 847
665=back 848=back
666 849
667=cut 850=cut
668 851
671no warnings; 854no warnings;
672use strict; 855use strict;
673 856
674use Carp; 857use Carp;
675 858
676our $VERSION = '3.3'; 859our $VERSION = 4.23;
677our $MODEL; 860our $MODEL;
678 861
679our $AUTOLOAD; 862our $AUTOLOAD;
680our @ISA; 863our @ISA;
681 864
865our @REGISTRY;
866
867our $WIN32;
868
869BEGIN {
870 my $win32 = ! ! ($^O =~ /mswin32/i);
871 eval "sub WIN32(){ $win32 }";
872}
873
682our $verbose = $ENV{PERL_ANYEVENT_VERBOSE}*1; 874our $verbose = $ENV{PERL_ANYEVENT_VERBOSE}*1;
683 875
684our @REGISTRY; 876our %PROTOCOL; # (ipv4|ipv6) => (1|2), higher numbers are preferred
877
878{
879 my $idx;
880 $PROTOCOL{$_} = ++$idx
881 for reverse split /\s*,\s*/,
882 $ENV{PERL_ANYEVENT_PROTOCOLS} || "ipv4,ipv6";
883}
685 884
686my @models = ( 885my @models = (
687 [Coro::EV:: => AnyEvent::Impl::CoroEV::],
688 [Coro::Event:: => AnyEvent::Impl::CoroEvent::],
689 [EV:: => AnyEvent::Impl::EV::], 886 [EV:: => AnyEvent::Impl::EV::],
690 [Event:: => AnyEvent::Impl::Event::], 887 [Event:: => AnyEvent::Impl::Event::],
691 [Tk:: => AnyEvent::Impl::Tk::],
692 [Wx:: => AnyEvent::Impl::POE::],
693 [Prima:: => AnyEvent::Impl::POE::],
694 [AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl::], 888 [AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl::],
695 # everything below here will not be autoprobed as the pureperl backend should work everywhere 889 # everything below here will not be autoprobed
696 [Glib:: => AnyEvent::Impl::Glib::], 890 # as the pureperl backend should work everywhere
891 # and is usually faster
892 [Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles
893 [Glib:: => AnyEvent::Impl::Glib::], # becomes extremely slow with many watchers
697 [Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy 894 [Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy
698 [Qt:: => AnyEvent::Impl::Qt::], # requires special main program 895 [Qt:: => AnyEvent::Impl::Qt::], # requires special main program
699 [POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza 896 [POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza
897 [Wx:: => AnyEvent::Impl::POE::],
898 [Prima:: => AnyEvent::Impl::POE::],
700); 899);
701 900
702our %method = map +($_ => 1), qw(io timer signal child condvar one_event DESTROY); 901our %method = map +($_ => 1), qw(io timer time now signal child condvar one_event DESTROY);
902
903our @post_detect;
904
905sub post_detect(&) {
906 my ($cb) = @_;
907
908 if ($MODEL) {
909 $cb->();
910
911 1
912 } else {
913 push @post_detect, $cb;
914
915 defined wantarray
916 ? bless \$cb, "AnyEvent::Util::PostDetect"
917 : ()
918 }
919}
920
921sub AnyEvent::Util::PostDetect::DESTROY {
922 @post_detect = grep $_ != ${$_[0]}, @post_detect;
923}
703 924
704sub detect() { 925sub detect() {
705 unless ($MODEL) { 926 unless ($MODEL) {
706 no strict 'refs'; 927 no strict 'refs';
928 local $SIG{__DIE__};
707 929
708 if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) { 930 if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) {
709 my $model = "AnyEvent::Impl::$1"; 931 my $model = "AnyEvent::Impl::$1";
710 if (eval "require $model") { 932 if (eval "require $model") {
711 $MODEL = $model; 933 $MODEL = $model;
741 last; 963 last;
742 } 964 }
743 } 965 }
744 966
745 $MODEL 967 $MODEL
746 or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV (or Coro+EV), Event (or Coro+Event) or Glib."; 968 or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV, Event or Glib.";
747 } 969 }
748 } 970 }
749 971
972 push @{"$MODEL\::ISA"}, "AnyEvent::Base";
973
750 unshift @ISA, $MODEL; 974 unshift @ISA, $MODEL;
751 push @{"$MODEL\::ISA"}, "AnyEvent::Base"; 975
976 require AnyEvent::Strict if $ENV{PERL_ANYEVENT_STRICT};
977
978 (shift @post_detect)->() while @post_detect;
752 } 979 }
753 980
754 $MODEL 981 $MODEL
755} 982}
756 983
764 991
765 my $class = shift; 992 my $class = shift;
766 $class->$func (@_); 993 $class->$func (@_);
767} 994}
768 995
996# utility function to dup a filehandle. this is used by many backends
997# to support binding more than one watcher per filehandle (they usually
998# allow only one watcher per fd, so we dup it to get a different one).
999sub _dupfh($$$$) {
1000 my ($poll, $fh, $r, $w) = @_;
1001
1002 require Fcntl;
1003
1004 # cygwin requires the fh mode to be matching, unix doesn't
1005 my ($rw, $mode) = $poll eq "r" ? ($r, "<")
1006 : $poll eq "w" ? ($w, ">")
1007 : Carp::croak "AnyEvent->io requires poll set to either 'r' or 'w'";
1008
1009 open my $fh2, "$mode&" . fileno $fh
1010 or die "cannot dup() filehandle: $!";
1011
1012 # we assume CLOEXEC is already set by perl in all important cases
1013
1014 ($fh2, $rw)
1015}
1016
769package AnyEvent::Base; 1017package AnyEvent::Base;
770 1018
1019# default implementation for now and time
1020
1021use Time::HiRes ();
1022
1023sub time { Time::HiRes::time }
1024sub now { Time::HiRes::time }
1025
771# default implementation for ->condvar, ->wait, ->broadcast 1026# default implementation for ->condvar
772 1027
773sub condvar { 1028sub condvar {
774 bless \my $flag, "AnyEvent::Base::CondVar" 1029 bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, AnyEvent::CondVar::
775}
776
777sub AnyEvent::Base::CondVar::broadcast {
778 ${$_[0]}++;
779}
780
781sub AnyEvent::Base::CondVar::wait {
782 AnyEvent->one_event while !${$_[0]};
783} 1030}
784 1031
785# default implementation for ->signal 1032# default implementation for ->signal
786 1033
787our %SIG_CB; 1034our %SIG_CB;
803sub AnyEvent::Base::Signal::DESTROY { 1050sub AnyEvent::Base::Signal::DESTROY {
804 my ($signal, $cb) = @{$_[0]}; 1051 my ($signal, $cb) = @{$_[0]};
805 1052
806 delete $SIG_CB{$signal}{$cb}; 1053 delete $SIG_CB{$signal}{$cb};
807 1054
808 $SIG{$signal} = 'DEFAULT' unless keys %{ $SIG_CB{$signal} }; 1055 delete $SIG{$signal} unless keys %{ $SIG_CB{$signal} };
809} 1056}
810 1057
811# default implementation for ->child 1058# default implementation for ->child
812 1059
813our %PID_CB; 1060our %PID_CB;
840 or Carp::croak "required option 'pid' is missing"; 1087 or Carp::croak "required option 'pid' is missing";
841 1088
842 $PID_CB{$pid}{$arg{cb}} = $arg{cb}; 1089 $PID_CB{$pid}{$arg{cb}} = $arg{cb};
843 1090
844 unless ($WNOHANG) { 1091 unless ($WNOHANG) {
845 $WNOHANG = eval { require POSIX; &POSIX::WNOHANG } || 1; 1092 $WNOHANG = eval { local $SIG{__DIE__}; require POSIX; &POSIX::WNOHANG } || 1;
846 } 1093 }
847 1094
848 unless ($CHLD_W) { 1095 unless ($CHLD_W) {
849 $CHLD_W = AnyEvent->signal (signal => 'CHLD', cb => \&_sigchld); 1096 $CHLD_W = AnyEvent->signal (signal => 'CHLD', cb => \&_sigchld);
850 # child could be a zombie already, so make at least one round 1097 # child could be a zombie already, so make at least one round
860 delete $PID_CB{$pid}{$cb}; 1107 delete $PID_CB{$pid}{$cb};
861 delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} }; 1108 delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };
862 1109
863 undef $CHLD_W unless keys %PID_CB; 1110 undef $CHLD_W unless keys %PID_CB;
864} 1111}
1112
1113package AnyEvent::CondVar;
1114
1115our @ISA = AnyEvent::CondVar::Base::;
1116
1117package AnyEvent::CondVar::Base;
1118
1119use overload
1120 '&{}' => sub { my $self = shift; sub { $self->send (@_) } },
1121 fallback => 1;
1122
1123sub _send {
1124 # nop
1125}
1126
1127sub send {
1128 my $cv = shift;
1129 $cv->{_ae_sent} = [@_];
1130 (delete $cv->{_ae_cb})->($cv) if $cv->{_ae_cb};
1131 $cv->_send;
1132}
1133
1134sub croak {
1135 $_[0]{_ae_croak} = $_[1];
1136 $_[0]->send;
1137}
1138
1139sub ready {
1140 $_[0]{_ae_sent}
1141}
1142
1143sub _wait {
1144 AnyEvent->one_event while !$_[0]{_ae_sent};
1145}
1146
1147sub recv {
1148 $_[0]->_wait;
1149
1150 Carp::croak $_[0]{_ae_croak} if $_[0]{_ae_croak};
1151 wantarray ? @{ $_[0]{_ae_sent} } : $_[0]{_ae_sent}[0]
1152}
1153
1154sub cb {
1155 $_[0]{_ae_cb} = $_[1] if @_ > 1;
1156 $_[0]{_ae_cb}
1157}
1158
1159sub begin {
1160 ++$_[0]{_ae_counter};
1161 $_[0]{_ae_end_cb} = $_[1] if @_ > 1;
1162}
1163
1164sub end {
1165 return if --$_[0]{_ae_counter};
1166 &{ $_[0]{_ae_end_cb} || sub { $_[0]->send } };
1167}
1168
1169# undocumented/compatibility with pre-3.4
1170*broadcast = \&send;
1171*wait = \&_wait;
865 1172
866=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE 1173=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE
867 1174
868This is an advanced topic that you do not normally need to use AnyEvent in 1175This is an advanced topic that you do not normally need to use AnyEvent in
869a module. This section is only of use to event loop authors who want to 1176a module. This section is only of use to event loop authors who want to
923C<PERL_ANYEVENT_MODEL>. 1230C<PERL_ANYEVENT_MODEL>.
924 1231
925When set to C<2> or higher, cause AnyEvent to report to STDERR which event 1232When set to C<2> or higher, cause AnyEvent to report to STDERR which event
926model it chooses. 1233model it chooses.
927 1234
1235=item C<PERL_ANYEVENT_STRICT>
1236
1237AnyEvent does not do much argument checking by default, as thorough
1238argument checking is very costly. Setting this variable to a true value
1239will cause AnyEvent to load C<AnyEvent::Strict> and then to thoroughly
1240check the arguments passed to most method calls. If it finds any problems
1241it will croak.
1242
1243In other words, enables "strict" mode.
1244
1245Unlike C<use strict> it is definitely recommended ot keep it off in
1246production.
1247
928=item C<PERL_ANYEVENT_MODEL> 1248=item C<PERL_ANYEVENT_MODEL>
929 1249
930This can be used to specify the event model to be used by AnyEvent, before 1250This can be used to specify the event model to be used by AnyEvent, before
931autodetection and -probing kicks in. It must be a string consisting 1251auto detection and -probing kicks in. It must be a string consisting
932entirely of ASCII letters. The string C<AnyEvent::Impl::> gets prepended 1252entirely of ASCII letters. The string C<AnyEvent::Impl::> gets prepended
933and the resulting module name is loaded and if the load was successful, 1253and the resulting module name is loaded and if the load was successful,
934used as event model. If it fails to load AnyEvent will proceed with 1254used as event model. If it fails to load AnyEvent will proceed with
935autodetection and -probing. 1255auto detection and -probing.
936 1256
937This functionality might change in future versions. 1257This functionality might change in future versions.
938 1258
939For example, to force the pure perl model (L<AnyEvent::Impl::Perl>) you 1259For example, to force the pure perl model (L<AnyEvent::Impl::Perl>) you
940could start your program like this: 1260could start your program like this:
941 1261
942 PERL_ANYEVENT_MODEL=Perl perl ... 1262 PERL_ANYEVENT_MODEL=Perl perl ...
1263
1264=item C<PERL_ANYEVENT_PROTOCOLS>
1265
1266Used by both L<AnyEvent::DNS> and L<AnyEvent::Socket> to determine preferences
1267for IPv4 or IPv6. The default is unspecified (and might change, or be the result
1268of auto probing).
1269
1270Must be set to a comma-separated list of protocols or address families,
1271current supported: C<ipv4> and C<ipv6>. Only protocols mentioned will be
1272used, and preference will be given to protocols mentioned earlier in the
1273list.
1274
1275This variable can effectively be used for denial-of-service attacks
1276against local programs (e.g. when setuid), although the impact is likely
1277small, as the program has to handle connection errors already-
1278
1279Examples: C<PERL_ANYEVENT_PROTOCOLS=ipv4,ipv6> - prefer IPv4 over IPv6,
1280but support both and try to use both. C<PERL_ANYEVENT_PROTOCOLS=ipv4>
1281- only support IPv4, never try to resolve or contact IPv6
1282addresses. C<PERL_ANYEVENT_PROTOCOLS=ipv6,ipv4> support either IPv4 or
1283IPv6, but prefer IPv6 over IPv4.
1284
1285=item C<PERL_ANYEVENT_EDNS0>
1286
1287Used by L<AnyEvent::DNS> to decide whether to use the EDNS0 extension
1288for DNS. This extension is generally useful to reduce DNS traffic, but
1289some (broken) firewalls drop such DNS packets, which is why it is off by
1290default.
1291
1292Setting this variable to C<1> will cause L<AnyEvent::DNS> to announce
1293EDNS0 in its DNS requests.
1294
1295=item C<PERL_ANYEVENT_MAX_FORKS>
1296
1297The maximum number of child processes that C<AnyEvent::Util::fork_call>
1298will create in parallel.
943 1299
944=back 1300=back
945 1301
946=head1 EXAMPLE PROGRAM 1302=head1 EXAMPLE PROGRAM
947 1303
958 poll => 'r', 1314 poll => 'r',
959 cb => sub { 1315 cb => sub {
960 warn "io event <$_[0]>\n"; # will always output <r> 1316 warn "io event <$_[0]>\n"; # will always output <r>
961 chomp (my $input = <STDIN>); # read a line 1317 chomp (my $input = <STDIN>); # read a line
962 warn "read: $input\n"; # output what has been read 1318 warn "read: $input\n"; # output what has been read
963 $cv->broadcast if $input =~ /^q/i; # quit program if /^q/i 1319 $cv->send if $input =~ /^q/i; # quit program if /^q/i
964 }, 1320 },
965 ); 1321 );
966 1322
967 my $time_watcher; # can only be used once 1323 my $time_watcher; # can only be used once
968 1324
973 }); 1329 });
974 } 1330 }
975 1331
976 new_timer; # create first timer 1332 new_timer; # create first timer
977 1333
978 $cv->wait; # wait until user enters /^q/i 1334 $cv->recv; # wait until user enters /^q/i
979 1335
980=head1 REAL-WORLD EXAMPLE 1336=head1 REAL-WORLD EXAMPLE
981 1337
982Consider the L<Net::FCP> module. It features (among others) the following 1338Consider the L<Net::FCP> module. It features (among others) the following
983API calls, which are to freenet what HTTP GET requests are to http: 1339API calls, which are to freenet what HTTP GET requests are to http:
1033 syswrite $txn->{fh}, $txn->{request} 1389 syswrite $txn->{fh}, $txn->{request}
1034 or die "connection or write error"; 1390 or die "connection or write error";
1035 $txn->{w} = AnyEvent->io (fh => $txn->{fh}, poll => 'r', cb => sub { $txn->fh_ready_r }); 1391 $txn->{w} = AnyEvent->io (fh => $txn->{fh}, poll => 'r', cb => sub { $txn->fh_ready_r });
1036 1392
1037Again, C<fh_ready_r> waits till all data has arrived, and then stores the 1393Again, C<fh_ready_r> waits till all data has arrived, and then stores the
1038result and signals any possible waiters that the request ahs finished: 1394result and signals any possible waiters that the request has finished:
1039 1395
1040 sysread $txn->{fh}, $txn->{buf}, length $txn->{$buf}; 1396 sysread $txn->{fh}, $txn->{buf}, length $txn->{$buf};
1041 1397
1042 if (end-of-file or data complete) { 1398 if (end-of-file or data complete) {
1043 $txn->{result} = $txn->{buf}; 1399 $txn->{result} = $txn->{buf};
1044 $txn->{finished}->broadcast; 1400 $txn->{finished}->send;
1045 $txb->{cb}->($txn) of $txn->{cb}; # also call callback 1401 $txb->{cb}->($txn) of $txn->{cb}; # also call callback
1046 } 1402 }
1047 1403
1048The C<result> method, finally, just waits for the finished signal (if the 1404The C<result> method, finally, just waits for the finished signal (if the
1049request was already finished, it doesn't wait, of course, and returns the 1405request was already finished, it doesn't wait, of course, and returns the
1050data: 1406data:
1051 1407
1052 $txn->{finished}->wait; 1408 $txn->{finished}->recv;
1053 return $txn->{result}; 1409 return $txn->{result};
1054 1410
1055The actual code goes further and collects all errors (C<die>s, exceptions) 1411The actual code goes further and collects all errors (C<die>s, exceptions)
1056that occured during request processing. The C<result> method detects 1412that occurred during request processing. The C<result> method detects
1057whether an exception as thrown (it is stored inside the $txn object) 1413whether an exception as thrown (it is stored inside the $txn object)
1058and just throws the exception, which means connection errors and other 1414and just throws the exception, which means connection errors and other
1059problems get reported tot he code that tries to use the result, not in a 1415problems get reported tot he code that tries to use the result, not in a
1060random callback. 1416random callback.
1061 1417
1092 1448
1093 my $quit = AnyEvent->condvar; 1449 my $quit = AnyEvent->condvar;
1094 1450
1095 $fcp->txn_client_get ($url)->cb (sub { 1451 $fcp->txn_client_get ($url)->cb (sub {
1096 ... 1452 ...
1097 $quit->broadcast; 1453 $quit->send;
1098 }); 1454 });
1099 1455
1100 $quit->wait; 1456 $quit->recv;
1101 1457
1102 1458
1103=head1 BENCHMARKS 1459=head1 BENCHMARKS
1104 1460
1105To give you an idea of the performance and overheads that AnyEvent adds 1461To give you an idea of the performance and overheads that AnyEvent adds
1107of various event loops I prepared some benchmarks. 1463of various event loops I prepared some benchmarks.
1108 1464
1109=head2 BENCHMARKING ANYEVENT OVERHEAD 1465=head2 BENCHMARKING ANYEVENT OVERHEAD
1110 1466
1111Here is a benchmark of various supported event models used natively and 1467Here is a benchmark of various supported event models used natively and
1112through anyevent. The benchmark creates a lot of timers (with a zero 1468through AnyEvent. The benchmark creates a lot of timers (with a zero
1113timeout) and I/O watchers (watching STDOUT, a pty, to become writable, 1469timeout) and I/O watchers (watching STDOUT, a pty, to become writable,
1114which it is), lets them fire exactly once and destroys them again. 1470which it is), lets them fire exactly once and destroys them again.
1115 1471
1116Source code for this benchmark is found as F<eg/bench> in the AnyEvent 1472Source code for this benchmark is found as F<eg/bench> in the AnyEvent
1117distribution. 1473distribution.
1134all watchers, to avoid adding memory overhead. That means closure creation 1490all watchers, to avoid adding memory overhead. That means closure creation
1135and memory usage is not included in the figures. 1491and memory usage is not included in the figures.
1136 1492
1137I<invoke> is the time, in microseconds, used to invoke a simple 1493I<invoke> is the time, in microseconds, used to invoke a simple
1138callback. The callback simply counts down a Perl variable and after it was 1494callback. The callback simply counts down a Perl variable and after it was
1139invoked "watcher" times, it would C<< ->broadcast >> a condvar once to 1495invoked "watcher" times, it would C<< ->send >> a condvar once to
1140signal the end of this phase. 1496signal the end of this phase.
1141 1497
1142I<destroy> is the time, in microseconds, that it takes to destroy a single 1498I<destroy> is the time, in microseconds, that it takes to destroy a single
1143watcher. 1499watcher.
1144 1500
1240 1596
1241=back 1597=back
1242 1598
1243=head2 BENCHMARKING THE LARGE SERVER CASE 1599=head2 BENCHMARKING THE LARGE SERVER CASE
1244 1600
1245This benchmark atcually benchmarks the event loop itself. It works by 1601This benchmark actually benchmarks the event loop itself. It works by
1246creating a number of "servers": each server consists of a socketpair, a 1602creating a number of "servers": each server consists of a socket pair, a
1247timeout watcher that gets reset on activity (but never fires), and an I/O 1603timeout watcher that gets reset on activity (but never fires), and an I/O
1248watcher waiting for input on one side of the socket. Each time the socket 1604watcher waiting for input on one side of the socket. Each time the socket
1249watcher reads a byte it will write that byte to a random other "server". 1605watcher reads a byte it will write that byte to a random other "server".
1250 1606
1251The effect is that there will be a lot of I/O watchers, only part of which 1607The effect is that there will be a lot of I/O watchers, only part of which
1252are active at any one point (so there is a constant number of active 1608are active at any one point (so there is a constant number of active
1253fds for each loop iterstaion, but which fds these are is random). The 1609fds for each loop iteration, but which fds these are is random). The
1254timeout is reset each time something is read because that reflects how 1610timeout is reset each time something is read because that reflects how
1255most timeouts work (and puts extra pressure on the event loops). 1611most timeouts work (and puts extra pressure on the event loops).
1256 1612
1257In this benchmark, we use 10000 socketpairs (20000 sockets), of which 100 1613In this benchmark, we use 10000 socket pairs (20000 sockets), of which 100
1258(1%) are active. This mirrors the activity of large servers with many 1614(1%) are active. This mirrors the activity of large servers with many
1259connections, most of which are idle at any one point in time. 1615connections, most of which are idle at any one point in time.
1260 1616
1261Source code for this benchmark is found as F<eg/bench2> in the AnyEvent 1617Source code for this benchmark is found as F<eg/bench2> in the AnyEvent
1262distribution. 1618distribution.
1264=head3 Explanation of the columns 1620=head3 Explanation of the columns
1265 1621
1266I<sockets> is the number of sockets, and twice the number of "servers" (as 1622I<sockets> is the number of sockets, and twice the number of "servers" (as
1267each server has a read and write socket end). 1623each server has a read and write socket end).
1268 1624
1269I<create> is the time it takes to create a socketpair (which is 1625I<create> is the time it takes to create a socket pair (which is
1270nontrivial) and two watchers: an I/O watcher and a timeout watcher. 1626nontrivial) and two watchers: an I/O watcher and a timeout watcher.
1271 1627
1272I<request>, the most important value, is the time it takes to handle a 1628I<request>, the most important value, is the time it takes to handle a
1273single "request", that is, reading the token from the pipe and forwarding 1629single "request", that is, reading the token from the pipe and forwarding
1274it to another server. This includes deleting the old timeout and creating 1630it to another server. This includes deleting the old timeout and creating
1347speed most when you have lots of watchers, not when you only have a few of 1703speed most when you have lots of watchers, not when you only have a few of
1348them). 1704them).
1349 1705
1350EV is again fastest. 1706EV is again fastest.
1351 1707
1352Perl again comes second. It is noticably faster than the C-based event 1708Perl again comes second. It is noticeably faster than the C-based event
1353loops Event and Glib, although the difference is too small to really 1709loops Event and Glib, although the difference is too small to really
1354matter. 1710matter.
1355 1711
1356POE also performs much better in this case, but is is still far behind the 1712POE also performs much better in this case, but is is still far behind the
1357others. 1713others.
1386specified in the variable. 1742specified in the variable.
1387 1743
1388You can make AnyEvent completely ignore this variable by deleting it 1744You can make AnyEvent completely ignore this variable by deleting it
1389before the first watcher gets created, e.g. with a C<BEGIN> block: 1745before the first watcher gets created, e.g. with a C<BEGIN> block:
1390 1746
1391 BEGIN { delete $ENV{PERL_ANYEVENT_MODEL} } 1747 BEGIN { delete $ENV{PERL_ANYEVENT_MODEL} }
1392 1748
1393 use AnyEvent; 1749 use AnyEvent;
1394 1750
1395Similar considerations apply to $ENV{PERL_ANYEVENT_VERBOSE}, as that can 1751Similar considerations apply to $ENV{PERL_ANYEVENT_VERBOSE}, as that can
1396be used to probe what backend is used and gain other information (which is 1752be used to probe what backend is used and gain other information (which is
1397probably even less useful to an attacker than PERL_ANYEVENT_MODEL). 1753probably even less useful to an attacker than PERL_ANYEVENT_MODEL), and
1754$ENV{PERL_ANYEGENT_STRICT}.
1755
1756
1757=head1 BUGS
1758
1759Perl 5.8 has numerous memleaks that sometimes hit this module and are hard
1760to work around. If you suffer from memleaks, first upgrade to Perl 5.10
1761and check wether the leaks still show up. (Perl 5.10.0 has other annoying
1762mamleaks, such as leaking on C<map> and C<grep> but it is usually not as
1763pronounced).
1398 1764
1399 1765
1400=head1 SEE ALSO 1766=head1 SEE ALSO
1401 1767
1402Event modules: L<Coro::EV>, L<EV>, L<EV::Glib>, L<Glib::EV>, 1768Utility functions: L<AnyEvent::Util>.
1403L<Coro::Event>, L<Event>, L<Glib::Event>, L<Glib>, L<Coro>, L<Tk>, 1769
1770Event modules: L<EV>, L<EV::Glib>, L<Glib::EV>, L<Event>, L<Glib::Event>,
1404L<Event::Lib>, L<Qt>, L<POE>. 1771L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>.
1405 1772
1406Implementations: L<AnyEvent::Impl::CoroEV>, L<AnyEvent::Impl::EV>, 1773Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>,
1407L<AnyEvent::Impl::CoroEvent>, L<AnyEvent::Impl::Event>, L<AnyEvent::Impl::Glib>, 1774L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>,
1408L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>, L<AnyEvent::Impl::EventLib>, 1775L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>,
1409L<AnyEvent::Impl::Qt>, L<AnyEvent::Impl::POE>. 1776L<AnyEvent::Impl::POE>.
1410 1777
1778Non-blocking file handles, sockets, TCP clients and
1779servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>.
1780
1781Asynchronous DNS: L<AnyEvent::DNS>.
1782
1783Coroutine support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>, L<Coro::Event>,
1784
1411Nontrivial usage examples: L<Net::FCP>, L<Net::XMPP2>. 1785Nontrivial usage examples: L<Net::FCP>, L<Net::XMPP2>, L<AnyEvent::DNS>.
1412 1786
1413 1787
1414=head1 AUTHOR 1788=head1 AUTHOR
1415 1789
1416 Marc Lehmann <schmorp@schmorp.de> 1790 Marc Lehmann <schmorp@schmorp.de>
1417 http://home.schmorp.de/ 1791 http://home.schmorp.de/
1418 1792
1419=cut 1793=cut
1420 1794
14211 17951
1422 1796

Diff Legend

Removed lines
+ Added lines
< Changed lines
> Changed lines