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 1.15 by root, Mon Oct 30 20:55:05 2006 UTC vs.
Revision 1.41 by root, Mon Apr 7 19:23:59 2008 UTC

17 }); 17 });
18 18
19 my $w = AnyEvent->condvar; # stores wether a condition was flagged 19 my $w = AnyEvent->condvar; # stores wether a condition was flagged
20 $w->wait; # enters "main loop" till $condvar gets ->broadcast 20 $w->wait; # enters "main loop" till $condvar gets ->broadcast
21 $w->broadcast; # wake up current and all future wait's 21 $w->broadcast; # wake up current and all future wait's
22
23=head1 WHY YOU SHOULD USE THIS MODULE
24
25Glib, POE, IO::Async, Event... CPAN offers event models by the dozen
26nowadays. So what is different about AnyEvent?
27
28Executive Summary: AnyEvent is I<compatible>, AnyEvent is I<free of
29policy> and AnyEvent is I<small and efficient>.
30
31First 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
33pragmatic way. For event models and certain classes of immortals alike,
34the statement "there can only be one" is a bitter reality, and AnyEvent
35helps hiding the differences.
36
37The goal of AnyEvent is to offer module authors the ability to do event
38programming (waiting for I/O or timer events) without subscribing to a
39religion, a way of living, and most importantly: without forcing your
40module users into the same thing by forcing them to use the same event
41model you use.
42
43For modules like POE or IO::Async (the latter of which is actually
44named confusingly, as it does neither do I/O nor does it do anything
45asynchronously...), using them in your module is like joining a
46cult: After you joined, you are dependent on them and you cannot use
47anything else, as it is simply incompatible to everything that isn't
48itself.
49
50AnyEvent + POE works fine. AnyEvent + Glib works fine. AnyEvent + Tk
51works fine etc. etc. but none of these work together with the rest: POE
52+ IO::Async? no go. Tk + Event? no go. If your module uses one of
53those, every user of your module has to use it, too. If your module
54uses AnyEvent, it works transparently with all event models it supports
55(including stuff like POE and IO::Async).
56
57In addition of being free of having to use I<the one and only true event
58model>, AnyEvent also is free of bloat and policy: with POE or similar
59modules, you get an enourmous amount of code and strict rules you have
60to follow. AnyEvent, on the other hand, is lean and to the point by only
61offering the functionality that is useful, in as thin as a wrapper as
62technically possible.
63
22 64
23=head1 DESCRIPTION 65=head1 DESCRIPTION
24 66
25L<AnyEvent> provides an identical interface to multiple event loops. This 67L<AnyEvent> provides an identical interface to multiple event loops. This
26allows module authors to utilise an event loop without forcing module 68allows module authors to utilise an event loop without forcing module
70You can create I/O watcher by calling the C<< AnyEvent->io >> method with 112You can create I/O watcher by calling the C<< AnyEvent->io >> method with
71the following mandatory arguments: 113the following mandatory arguments:
72 114
73C<fh> the Perl I<filehandle> (not filedescriptor) to watch for 115C<fh> the Perl I<filehandle> (not filedescriptor) to watch for
74events. C<poll> must be a string that is either C<r> or C<w>, that creates 116events. C<poll> must be a string that is either C<r> or C<w>, that creates
75a watcher waiting for "r"eadable or "w"ritable events. C<cb> teh callback 117a watcher waiting for "r"eadable or "w"ritable events. C<cb> the callback
76to invoke everytime the filehandle becomes ready. 118to invoke everytime the filehandle becomes ready.
77 119
78Only one io watcher per C<fh> and C<poll> combination is allowed (i.e. on 120Only one io watcher per C<fh> and C<poll> combination is allowed (i.e. on
79a socket you can have one r + one w, not any more (limitation comes from 121a socket you can have one r + one w, not any more (limitation comes from
80Tk - if you are sure you are not using Tk this limitation is gone). 122Tk - if you are sure you are not using Tk this limitation is gone).
89 chomp (my $input = <STDIN>); 131 chomp (my $input = <STDIN>);
90 warn "read: $input\n"; 132 warn "read: $input\n";
91 undef $w; 133 undef $w;
92 }); 134 });
93 135
94=head2 TIMER WATCHERS 136=head2 TIME WATCHERS
95 137
96You can create a timer watcher by calling the C<< AnyEvent->timer >> 138You can create a time watcher by calling the C<< AnyEvent->timer >>
97method with the following mandatory arguments: 139method with the following mandatory arguments:
98 140
99C<after> after how many seconds (fractions are supported) should the timer 141C<after> after how many seconds (fractions are supported) should the timer
100activate. C<cb> the callback to invoke. 142activate. C<cb> the callback to invoke.
101 143
109 my $w = AnyEvent->timer (after => 7.7, cb => sub { 151 my $w = AnyEvent->timer (after => 7.7, cb => sub {
110 warn "timeout\n"; 152 warn "timeout\n";
111 }); 153 });
112 154
113 # to cancel the timer: 155 # to cancel the timer:
114 undef $w 156 undef $w;
115 157
116=head2 CONDITION WATCHERS 158=head2 CONDITION WATCHERS
117 159
118Condition watchers can be created by calling the C<< AnyEvent->condvar >> 160Condition watchers can be created by calling the C<< AnyEvent->condvar >>
119method without any arguments. 161method without any arguments.
120 162
121A condition watcher watches for a condition - precisely that the C<< 163A condition watcher watches for a condition - precisely that the C<<
122->broadcast >> method has been called. 164->broadcast >> method has been called.
165
166Note that condition watchers recurse into the event loop - if you have
167two watchers that call C<< ->wait >> in a round-robbin fashion, you
168lose. Therefore, condition watchers are good to export to your caller, but
169you should avoid making a blocking wait, at least in callbacks, as this
170usually asks for trouble.
123 171
124The watcher has only two methods: 172The watcher has only two methods:
125 173
126=over 4 174=over 4
127 175
154 # do something such as adding a timer 202 # do something such as adding a timer
155 # or socket watcher the calls $result_ready->broadcast 203 # or socket watcher the calls $result_ready->broadcast
156 # when the "result" is ready. 204 # when the "result" is ready.
157 205
158 $result_ready->wait; 206 $result_ready->wait;
207
208=back
209
210=head2 SIGNAL WATCHERS
211
212You can listen for signals using a signal watcher, C<signal> is the signal
213I<name> without any C<SIG> prefix. Multiple signals events can be clumped
214together into one callback invocation, and callback invocation might or
215might not be asynchronous.
216
217These watchers might use C<%SIG>, so programs overwriting those signals
218directly will likely not work correctly.
219
220Example: exit on SIGINT
221
222 my $w = AnyEvent->signal (signal => "INT", cb => sub { exit 1 });
223
224=head2 CHILD PROCESS WATCHERS
225
226You can also listen for the status of a child process specified by the
227C<pid> argument (or any child if the pid argument is 0). The watcher will
228trigger as often as status change for the child are received. This works
229by installing a signal handler for C<SIGCHLD>. The callback will be called with
230the pid and exit status (as returned by waitpid).
231
232Example: wait for pid 1333
233
234 my $w = AnyEvent->child (pid => 1333, cb => sub { warn "exit status $?" });
235
236=head1 GLOBALS
237
238=over 4
239
240=item $AnyEvent::MODEL
241
242Contains C<undef> until the first watcher is being created. Then it
243contains the event model that is being used, which is the name of the
244Perl class implementing the model. This class is usually one of the
245C<AnyEvent::Impl:xxx> modules, but can be any other class in the case
246AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode>).
247
248The known classes so far are:
249
250 AnyEvent::Impl::CoroEV based on Coro::EV, best choice.
251 AnyEvent::Impl::EV based on EV (an interface to libev, also best choice).
252 AnyEvent::Impl::CoroEvent based on Coro::Event, second best choice.
253 AnyEvent::Impl::Event based on Event, also second best choice :)
254 AnyEvent::Impl::Glib based on Glib, second-best choice.
255 AnyEvent::Impl::Tk based on Tk, very bad choice.
256 AnyEvent::Impl::Perl pure-perl implementation, inefficient.
257
258=item AnyEvent::detect
259
260Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model if
261necessary. You should only call this function right before you would have
262created an AnyEvent watcher anyway, that is, very late at runtime.
159 263
160=back 264=back
161 265
162=head1 WHAT TO DO IN A MODULE 266=head1 WHAT TO DO IN A MODULE
163 267
192=cut 296=cut
193 297
194package AnyEvent; 298package AnyEvent;
195 299
196no warnings; 300no warnings;
197use strict 'vars'; 301use strict;
302
198use Carp; 303use Carp;
199 304
200our $VERSION = '2.0'; 305our $VERSION = '3.0';
201our $MODEL; 306our $MODEL;
202 307
203our $AUTOLOAD; 308our $AUTOLOAD;
204our @ISA; 309our @ISA;
205 310
206our $verbose = $ENV{PERL_ANYEVENT_VERBOSE}*1; 311our $verbose = $ENV{PERL_ANYEVENT_VERBOSE}*1;
207 312
208our @REGISTRY; 313our @REGISTRY;
209 314
210my @models = ( 315my @models = (
316 [Coro::EV:: => AnyEvent::Impl::CoroEV::],
317 [EV:: => AnyEvent::Impl::EV::],
211 [Coro::Event:: => AnyEvent::Impl::Coro::], 318 [Coro::Event:: => AnyEvent::Impl::CoroEvent::],
212 [Event:: => AnyEvent::Impl::Event::], 319 [Event:: => AnyEvent::Impl::Event::],
213 [Glib:: => AnyEvent::Impl::Glib::], 320 [Glib:: => AnyEvent::Impl::Glib::],
214 [Tk:: => AnyEvent::Impl::Tk::], 321 [Tk:: => AnyEvent::Impl::Tk::],
215 [AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl::], 322 [AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl::],
216); 323);
217 324
218our %method = map +($_ => 1), qw(io timer condvar broadcast wait DESTROY); 325our %method = map +($_ => 1), qw(io timer condvar broadcast wait signal one_event DESTROY);
219 326
220sub AUTOLOAD { 327sub detect() {
221 $AUTOLOAD =~ s/.*://;
222
223 $method{$AUTOLOAD}
224 or croak "$AUTOLOAD: not a valid method for AnyEvent objects";
225
226 unless ($MODEL) { 328 unless ($MODEL) {
329 no strict 'refs';
330
227 # check for already loaded models 331 # check for already loaded models
228 for (@REGISTRY, @models) { 332 for (@REGISTRY, @models) {
229 my ($package, $model) = @$_; 333 my ($package, $model) = @$_;
230 if (${"$package\::VERSION"} > 0) { 334 if (${"$package\::VERSION"} > 0) {
231 if (eval "require $model") { 335 if (eval "require $model") {
239 unless ($MODEL) { 343 unless ($MODEL) {
240 # try to load a model 344 # try to load a model
241 345
242 for (@REGISTRY, @models) { 346 for (@REGISTRY, @models) {
243 my ($package, $model) = @$_; 347 my ($package, $model) = @$_;
348 if (eval "require $package"
349 and ${"$package\::VERSION"} > 0
244 if (eval "require $model") { 350 and eval "require $model") {
245 $MODEL = $model; 351 $MODEL = $model;
246 warn "AnyEvent: autoprobed and loaded model '$model', using it.\n" if $verbose > 1; 352 warn "AnyEvent: autoprobed and loaded model '$model', using it.\n" if $verbose > 1;
247 last; 353 last;
248 } 354 }
249 } 355 }
250 356
251 $MODEL 357 $MODEL
252 or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: Coro, Event, Glib or Tk."; 358 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), Glib or Tk.";
253 } 359 }
360
361 unshift @ISA, $MODEL;
362 push @{"$MODEL\::ISA"}, "AnyEvent::Base";
254 } 363 }
255 364
256 @ISA = $MODEL; 365 $MODEL
366}
367
368sub AUTOLOAD {
369 (my $func = $AUTOLOAD) =~ s/.*://;
370
371 $method{$func}
372 or croak "$func: not a valid method for AnyEvent objects";
373
374 detect unless $MODEL;
257 375
258 my $class = shift; 376 my $class = shift;
259 $class->$AUTOLOAD (@_); 377 $class->$func (@_);
378}
379
380package AnyEvent::Base;
381
382# default implementation for ->condvar, ->wait, ->broadcast
383
384sub condvar {
385 bless \my $flag, "AnyEvent::Base::CondVar"
386}
387
388sub AnyEvent::Base::CondVar::broadcast {
389 ${$_[0]}++;
390}
391
392sub AnyEvent::Base::CondVar::wait {
393 AnyEvent->one_event while !${$_[0]};
394}
395
396# default implementation for ->signal
397
398our %SIG_CB;
399
400sub signal {
401 my (undef, %arg) = @_;
402
403 my $signal = uc $arg{signal}
404 or Carp::croak "required option 'signal' is missing";
405
406 $SIG_CB{$signal}{$arg{cb}} = $arg{cb};
407 $SIG{$signal} ||= sub {
408 $_->() for values %{ $SIG_CB{$signal} || {} };
409 };
410
411 bless [$signal, $arg{cb}], "AnyEvent::Base::Signal"
412}
413
414sub AnyEvent::Base::Signal::DESTROY {
415 my ($signal, $cb) = @{$_[0]};
416
417 delete $SIG_CB{$signal}{$cb};
418
419 $SIG{$signal} = 'DEFAULT' unless keys %{ $SIG_CB{$signal} };
420}
421
422# default implementation for ->child
423
424our %PID_CB;
425our $CHLD_W;
426our $CHLD_DELAY_W;
427our $PID_IDLE;
428our $WNOHANG;
429
430sub _child_wait {
431 while (0 < (my $pid = waitpid -1, $WNOHANG)) {
432 $_->($pid, $?) for (values %{ $PID_CB{$pid} || {} }),
433 (values %{ $PID_CB{0} || {} });
434 }
435
436 undef $PID_IDLE;
437}
438
439sub _sigchld {
440 # make sure we deliver these changes "synchronous" with the event loop.
441 $CHLD_DELAY_W ||= AnyEvent->timer (after => 0, cb => sub {
442 undef $CHLD_DELAY_W;
443 &_child_wait;
444 });
445}
446
447sub child {
448 my (undef, %arg) = @_;
449
450 defined (my $pid = $arg{pid} + 0)
451 or Carp::croak "required option 'pid' is missing";
452
453 $PID_CB{$pid}{$arg{cb}} = $arg{cb};
454
455 unless ($WNOHANG) {
456 $WNOHANG = eval { require POSIX; &POSIX::WNOHANG } || 1;
457 }
458
459 unless ($CHLD_W) {
460 $CHLD_W = AnyEvent->signal (signal => 'CHLD', cb => \&_sigchld);
461 # child could be a zombie already, so make at least one round
462 &_sigchld;
463 }
464
465 bless [$pid, $arg{cb}], "AnyEvent::Base::Child"
466}
467
468sub AnyEvent::Base::Child::DESTROY {
469 my ($pid, $cb) = @{$_[0]};
470
471 delete $PID_CB{$pid}{$cb};
472 delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };
473
474 undef $CHLD_W unless keys %PID_CB;
260} 475}
261 476
262=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE 477=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE
263 478
264If you need to support another event library which isn't directly 479If you need to support another event library which isn't directly
275This tells AnyEvent to (literally) use the C<urxvt::anyevent::> 490This tells AnyEvent to (literally) use the C<urxvt::anyevent::>
276package/class when it finds the C<urxvt> package/module is loaded. When 491package/class when it finds the C<urxvt> package/module is loaded. When
277AnyEvent is loaded and asked to find a suitable event model, it will 492AnyEvent is loaded and asked to find a suitable event model, it will
278first check for the presence of urxvt. 493first check for the presence of urxvt.
279 494
280The class should prove implementations for all watcher types (see 495The class should provide implementations for all watcher types (see
281L<AnyEvent::Impl::Event> (source code), L<AnyEvent::Impl::Glib> 496L<AnyEvent::Impl::Event> (source code), L<AnyEvent::Impl::Glib>
282(Source code) and so on for actual examples, use C<perldoc -m 497(Source code) and so on for actual examples, use C<perldoc -m
283AnyEvent::Impl::Glib> to see the sources). 498AnyEvent::Impl::Glib> to see the sources).
284 499
285The above isn't fictitious, the I<rxvt-unicode> (a.k.a. urxvt) 500The above isn't fictitious, the I<rxvt-unicode> (a.k.a. urxvt)
289I<rxvt-unicode> distribution. 504I<rxvt-unicode> distribution.
290 505
291I<rxvt-unicode> also cheats a bit by not providing blocking access to 506I<rxvt-unicode> also cheats a bit by not providing blocking access to
292condition variables: code blocking while waiting for a condition will 507condition variables: code blocking while waiting for a condition will
293C<die>. This still works with most modules/usages, and blocking calls must 508C<die>. This still works with most modules/usages, and blocking calls must
294not be in an interactive appliation, so it makes sense. 509not be in an interactive application, so it makes sense.
295 510
296=head1 ENVIRONMENT VARIABLES 511=head1 ENVIRONMENT VARIABLES
297 512
298The following environment variables are used by this module: 513The following environment variables are used by this module:
299 514

Diff Legend

Removed lines
+ Added lines
< Changed lines
> Changed lines