… | |
… | |
58 | This module provides an interface to libev |
58 | This module provides an interface to libev |
59 | (L<http://software.schmorp.de/pkg/libev.html>). While the documentation |
59 | (L<http://software.schmorp.de/pkg/libev.html>). While the documentation |
60 | below is comprehensive, one might also consult the documentation of libev |
60 | below is comprehensive, one might also consult the documentation of libev |
61 | itself (L<http://cvs.schmorp.de/libev/ev.html>) for more subtle details on |
61 | itself (L<http://cvs.schmorp.de/libev/ev.html>) for more subtle details on |
62 | watcher semantics or some discussion on the available backends, or how to |
62 | watcher semantics or some discussion on the available backends, or how to |
63 | force a specific backend with C<LIBEV_FLAGS>. |
63 | force a specific backend with C<LIBEV_FLAGS>, or just about in any case |
|
|
64 | because it has much more detailed information. |
64 | |
65 | |
65 | =cut |
66 | =cut |
66 | |
67 | |
67 | package EV; |
68 | package EV; |
68 | |
69 | |
69 | use strict; |
70 | use strict; |
70 | |
71 | |
71 | BEGIN { |
72 | BEGIN { |
72 | our $VERSION = '1.4'; |
73 | our $VERSION = '2.0'; |
73 | use XSLoader; |
74 | use XSLoader; |
74 | XSLoader::load "EV", $VERSION; |
75 | XSLoader::load "EV", $VERSION; |
75 | } |
76 | } |
76 | |
77 | |
77 | @EV::IO::ISA = |
78 | @EV::IO::ISA = |
78 | @EV::Timer::ISA = |
79 | @EV::Timer::ISA = |
79 | @EV::Periodic::ISA = |
80 | @EV::Periodic::ISA = |
80 | @EV::Signal::ISA = |
81 | @EV::Signal::ISA = |
|
|
82 | @EV::Child::ISA = |
|
|
83 | @EV::Stat::ISA = |
81 | @EV::Idle::ISA = |
84 | @EV::Idle::ISA = |
82 | @EV::Prepare::ISA = |
85 | @EV::Prepare::ISA = |
83 | @EV::Check::ISA = |
86 | @EV::Check::ISA = |
84 | @EV::Child::ISA = |
|
|
85 | @EV::Embed::ISA = |
87 | @EV::Embed::ISA = |
86 | @EV::Stat::ISA = "EV::Watcher"; |
88 | @EV::Fork::ISA = |
|
|
89 | "EV::Watcher"; |
|
|
90 | |
|
|
91 | @EV::Loop::Default::ISA = "EV::Loop"; |
87 | |
92 | |
88 | =head1 BASIC INTERFACE |
93 | =head1 BASIC INTERFACE |
89 | |
94 | |
90 | =over 4 |
95 | =over 4 |
91 | |
96 | |
92 | =item $EV::DIED |
97 | =item $EV::DIED |
93 | |
98 | |
94 | Must contain a reference to a function that is called when a callback |
99 | Must contain a reference to a function that is called when a callback |
95 | throws an exception (with $@ containing thr error). The default prints an |
100 | throws an exception (with $@ containing the error). The default prints an |
96 | informative message and continues. |
101 | informative message and continues. |
97 | |
102 | |
98 | If this callback throws an exception it will be silently ignored. |
103 | If this callback throws an exception it will be silently ignored. |
99 | |
104 | |
100 | =item $time = EV::time |
105 | =item $time = EV::time |
… | |
… | |
128 | When called with no arguments or an argument of EV::UNLOOP_ONE, makes the |
133 | When called with no arguments or an argument of EV::UNLOOP_ONE, makes the |
129 | innermost call to EV::loop return. |
134 | innermost call to EV::loop return. |
130 | |
135 | |
131 | When called with an argument of EV::UNLOOP_ALL, all calls to EV::loop will return as |
136 | When called with an argument of EV::UNLOOP_ALL, all calls to EV::loop will return as |
132 | fast as possible. |
137 | fast as possible. |
|
|
138 | |
|
|
139 | =item $count = EV::loop_count |
|
|
140 | |
|
|
141 | Return the number of times the event loop has polled for new |
|
|
142 | events. Sometiems useful as a generation counter. |
133 | |
143 | |
134 | =item EV::once $fh_or_undef, $events, $timeout, $cb->($revents) |
144 | =item EV::once $fh_or_undef, $events, $timeout, $cb->($revents) |
135 | |
145 | |
136 | This function rolls together an I/O and a timer watcher for a single |
146 | This function rolls together an I/O and a timer watcher for a single |
137 | one-shot event without the need for managing a watcher object. |
147 | one-shot event without the need for managing a watcher object. |
… | |
… | |
152 | |
162 | |
153 | EV::once doesn't return anything: the watchers stay active till either |
163 | EV::once doesn't return anything: the watchers stay active till either |
154 | of them triggers, then they will be stopped and freed, and the callback |
164 | of them triggers, then they will be stopped and freed, and the callback |
155 | invoked. |
165 | invoked. |
156 | |
166 | |
|
|
167 | =item EV::feed_fd_event ($fd, $revents) |
|
|
168 | |
|
|
169 | Feed an event on a file descriptor into EV. EV will react to this call as |
|
|
170 | if the readyness notifications specified by C<$revents> (a combination of |
|
|
171 | C<EV::READ> and C<EV::WRITE>) happened on the file descriptor C<$fd>. |
|
|
172 | |
|
|
173 | =item EV::feed_signal_event ($signal) |
|
|
174 | |
|
|
175 | Feed a signal event into EV. EV will react to this call as if the signal |
|
|
176 | specified by C<$signal> had occured. |
|
|
177 | |
157 | =back |
178 | =back |
|
|
179 | |
158 | |
180 | |
159 | =head2 WATCHER OBJECTS |
181 | =head2 WATCHER OBJECTS |
160 | |
182 | |
161 | A watcher is an object that gets created to record your interest in some |
183 | A watcher is an object that gets created to record your interest in some |
162 | event. For instance, if you want to wait for STDIN to become readable, you |
184 | event. For instance, if you want to wait for STDIN to become readable, you |
… | |
… | |
173 | events. |
195 | events. |
174 | |
196 | |
175 | Each watcher type has its associated bit in revents, so you can use the |
197 | Each watcher type has its associated bit in revents, so you can use the |
176 | same callback for multiple watchers. The event mask is named after the |
198 | same callback for multiple watchers. The event mask is named after the |
177 | type, i..e. EV::child sets EV::CHILD, EV::prepare sets EV::PREPARE, |
199 | type, i..e. EV::child sets EV::CHILD, EV::prepare sets EV::PREPARE, |
178 | EV::periodic sets EV::PERIODIC and so on, with the exception of IO events |
200 | EV::periodic sets EV::PERIODIC and so on, with the exception of I/O events |
179 | (which can set both EV::READ and EV::WRITE bits), and EV::timer (which |
201 | (which can set both EV::READ and EV::WRITE bits), and EV::timer (which |
180 | uses EV::TIMEOUT). |
202 | uses EV::TIMEOUT). |
181 | |
203 | |
182 | In the rare case where one wants to create a watcher but not start it at |
204 | In the rare case where one wants to create a watcher but not start it at |
183 | the same time, each constructor has a variant with a trailing C<_ns> in |
205 | the same time, each constructor has a variant with a trailing C<_ns> in |
… | |
… | |
205 | |
227 | |
206 | =item $w->stop |
228 | =item $w->stop |
207 | |
229 | |
208 | Stop a watcher if it is active. Also clear any pending events (events that |
230 | Stop a watcher if it is active. Also clear any pending events (events that |
209 | have been received but that didn't yet result in a callback invocation), |
231 | have been received but that didn't yet result in a callback invocation), |
210 | regardless of wether the watcher was active or not. |
232 | regardless of whether the watcher was active or not. |
211 | |
233 | |
212 | =item $bool = $w->is_active |
234 | =item $bool = $w->is_active |
213 | |
235 | |
214 | Returns true if the watcher is active, false otherwise. |
236 | Returns true if the watcher is active, false otherwise. |
215 | |
237 | |
… | |
… | |
245 | The default priority of any newly-created watcher is 0. |
267 | The default priority of any newly-created watcher is 0. |
246 | |
268 | |
247 | Note that the priority semantics have not yet been fleshed out and are |
269 | Note that the priority semantics have not yet been fleshed out and are |
248 | subject to almost certain change. |
270 | subject to almost certain change. |
249 | |
271 | |
250 | =item $w->trigger ($revents) |
272 | =item $w->invoke ($revents) |
251 | |
273 | |
252 | Call the callback *now* with the given event mask. |
274 | Call the callback *now* with the given event mask. |
|
|
275 | |
|
|
276 | =item $w->feed_event ($revents) |
|
|
277 | |
|
|
278 | Feed some events on this watcher into EV. EV will react to this call as if |
|
|
279 | the watcher had received the given C<$revents> mask. |
|
|
280 | |
|
|
281 | =item $revents = $w->clear_pending |
|
|
282 | |
|
|
283 | If the watcher is pending, this function returns clears its pending status |
|
|
284 | and returns its C<$revents> bitset (as if its callback was invoked). If the |
|
|
285 | watcher isn't pending it does nothing and returns C<0>. |
253 | |
286 | |
254 | =item $previous_state = $w->keepalive ($bool) |
287 | =item $previous_state = $w->keepalive ($bool) |
255 | |
288 | |
256 | Normally, C<EV::loop> will return when there are no active watchers |
289 | Normally, C<EV::loop> will return when there are no active watchers |
257 | (which is a "deadlock" because no progress can be made anymore). This is |
290 | (which is a "deadlock" because no progress can be made anymore). This is |
… | |
… | |
270 | though your watcher is active, it won't keep C<EV::loop> from returning. |
303 | though your watcher is active, it won't keep C<EV::loop> from returning. |
271 | |
304 | |
272 | The initial value for keepalive is true (enabled), and you cna change it |
305 | The initial value for keepalive is true (enabled), and you cna change it |
273 | any time. |
306 | any time. |
274 | |
307 | |
275 | Example: Register an IO watcher for some UDP socket but do not keep the |
308 | Example: Register an I/O watcher for some UDP socket but do not keep the |
276 | event loop from running just because of that watcher. |
309 | event loop from running just because of that watcher. |
277 | |
310 | |
278 | my $udp_socket = ... |
311 | my $udp_socket = ... |
279 | my $udp_watcher = EV::io $udp_socket, EV::READ, sub { ... }; |
312 | my $udp_watcher = EV::io $udp_socket, EV::READ, sub { ... }; |
280 | $udp_watcher->keepalive (0); |
313 | $udp_watcher->keepalive (0); |
… | |
… | |
284 | |
317 | |
285 | =head2 WATCHER TYPES |
318 | =head2 WATCHER TYPES |
286 | |
319 | |
287 | Each of the following subsections describes a single watcher type. |
320 | Each of the following subsections describes a single watcher type. |
288 | |
321 | |
289 | =head3 IO WATCHERS - is this file descriptor readable or writable? |
322 | =head3 I/O WATCHERS - is this file descriptor readable or writable? |
290 | |
323 | |
291 | =over 4 |
324 | =over 4 |
292 | |
325 | |
293 | =item $w = EV::io $fileno_or_fh, $eventmask, $callback |
326 | =item $w = EV::io $fileno_or_fh, $eventmask, $callback |
294 | |
327 | |
… | |
… | |
463 | |
496 | |
464 | =item $w->again |
497 | =item $w->again |
465 | |
498 | |
466 | Simply stops and starts the watcher again. |
499 | Simply stops and starts the watcher again. |
467 | |
500 | |
|
|
501 | =item $time = $w->at |
|
|
502 | |
|
|
503 | Return the time that the watcher is expected to trigger next. |
|
|
504 | |
468 | =back |
505 | =back |
469 | |
506 | |
470 | |
507 | |
471 | =head3 SIGNAL WATCHERS - signal me when a signal gets signalled! |
508 | =head3 SIGNAL WATCHERS - signal me when a signal gets signalled! |
472 | |
509 | |
… | |
… | |
551 | watcher for all pids). |
588 | watcher for all pids). |
552 | |
589 | |
553 | =back |
590 | =back |
554 | |
591 | |
555 | |
592 | |
|
|
593 | =head3 STAT WATCHERS - did the file attributes just change? |
|
|
594 | |
|
|
595 | =over 4 |
|
|
596 | |
|
|
597 | =item $w = EV::stat $path, $interval, $callback |
|
|
598 | |
|
|
599 | =item $w = EV::stat_ns $path, $interval, $callback |
|
|
600 | |
|
|
601 | Call the callback when a file status change has been detected on |
|
|
602 | C<$path>. The C<$path> does not need to exist, changing from "path exists" |
|
|
603 | to "path does not exist" is a status change like any other. |
|
|
604 | |
|
|
605 | The C<$interval> is a recommended polling interval for systems where |
|
|
606 | OS-supported change notifications don't exist or are not supported. If |
|
|
607 | you use C<0> then an unspecified default is used (which is highly |
|
|
608 | recommended!), which is to be expected to be around five seconds usually. |
|
|
609 | |
|
|
610 | This watcher type is not meant for massive numbers of stat watchers, |
|
|
611 | as even with OS-supported change notifications, this can be |
|
|
612 | resource-intensive. |
|
|
613 | |
|
|
614 | The C<stat_ns> variant doesn't start (activate) the newly created watcher. |
|
|
615 | |
|
|
616 | =item ... = $w->stat |
|
|
617 | |
|
|
618 | This call is very similar to the perl C<stat> built-in: It stats (using |
|
|
619 | C<lstat>) the path specified in the watcher and sets perls stat cache (as |
|
|
620 | well as EV's idea of the current stat values) to the values found. |
|
|
621 | |
|
|
622 | In scalar context, a boolean is return indicating success or failure of |
|
|
623 | the stat. In list context, the same 13-value list as with stat is returned |
|
|
624 | (except that the blksize and blocks fields are not reliable). |
|
|
625 | |
|
|
626 | In the case of an error, errno is set to C<ENOENT> (regardless of the |
|
|
627 | actual error value) and the C<nlink> value is forced to zero (if the stat |
|
|
628 | was successful then nlink is guaranteed to be non-zero). |
|
|
629 | |
|
|
630 | See also the next two entries for more info. |
|
|
631 | |
|
|
632 | =item ... = $w->attr |
|
|
633 | |
|
|
634 | Just like C<< $w->stat >>, but without the initial stat'ing: this returns |
|
|
635 | the values most recently detected by EV. See the next entry for more info. |
|
|
636 | |
|
|
637 | =item ... = $w->prev |
|
|
638 | |
|
|
639 | Just like C<< $w->stat >>, but without the initial stat'ing: this returns |
|
|
640 | the previous set of values, before the change. |
|
|
641 | |
|
|
642 | That is, when the watcher callback is invoked, C<< $w->prev >> will be set |
|
|
643 | to the values found I<before> a change was detected, while C<< $w->attr >> |
|
|
644 | returns the values found leading to the change detection. The difference (if any) |
|
|
645 | between C<prev> and C<attr> is what triggered the callback. |
|
|
646 | |
|
|
647 | If you did something to the filesystem object and do not want to trigger |
|
|
648 | yet another change, you can call C<stat> to update EV's idea of what the |
|
|
649 | current attributes are. |
|
|
650 | |
|
|
651 | =item $w->set ($path, $interval) |
|
|
652 | |
|
|
653 | Reconfigures the watcher, see the constructor above for details. Can be |
|
|
654 | called at any time. |
|
|
655 | |
|
|
656 | =item $current_path = $w->path |
|
|
657 | |
|
|
658 | =item $old_path = $w->path ($new_path) |
|
|
659 | |
|
|
660 | Returns the previously set path and optionally set a new one. |
|
|
661 | |
|
|
662 | =item $current_interval = $w->interval |
|
|
663 | |
|
|
664 | =item $old_interval = $w->interval ($new_interval) |
|
|
665 | |
|
|
666 | Returns the previously set interval and optionally set a new one. Can be |
|
|
667 | used to query the actual interval used. |
|
|
668 | |
|
|
669 | =back |
|
|
670 | |
|
|
671 | |
556 | =head3 IDLE WATCHERS - when you've got nothing better to do... |
672 | =head3 IDLE WATCHERS - when you've got nothing better to do... |
557 | |
673 | |
558 | =over 4 |
674 | =over 4 |
559 | |
675 | |
560 | =item $w = EV::idle $callback |
676 | =item $w = EV::idle $callback |
561 | |
677 | |
562 | =item $w = EV::idle_ns $callback |
678 | =item $w = EV::idle_ns $callback |
563 | |
679 | |
564 | Call the callback when there are no pending io, timer/periodic, signal or |
680 | Call the callback when there are no other pending watchers of the same or |
565 | child events, i.e. when the process is idle. |
681 | higher priority (excluding check, prepare and other idle watchers of the |
|
|
682 | same or lower priority, of course). They are called idle watchers because |
|
|
683 | when the watcher is the highest priority pending event in the process, the |
|
|
684 | process is considered to be idle at that priority. |
|
|
685 | |
|
|
686 | If you want a watcher that is only ever called when I<no> other events are |
|
|
687 | outstanding you have to set the priority to C<EV::MINPRI>. |
566 | |
688 | |
567 | The process will not block as long as any idle watchers are active, and |
689 | The process will not block as long as any idle watchers are active, and |
568 | they will be called repeatedly until stopped. |
690 | they will be called repeatedly until stopped. |
|
|
691 | |
|
|
692 | For example, if you have idle watchers at priority C<0> and C<1>, and |
|
|
693 | an I/O watcher at priority C<0>, then the idle watcher at priority C<1> |
|
|
694 | and the I/O watcher will always run when ready. Only when the idle watcher |
|
|
695 | at priority C<1> is stopped and the I/O watcher at priority C<0> is not |
|
|
696 | pending with the C<0>-priority idle watcher be invoked. |
569 | |
697 | |
570 | The C<idle_ns> variant doesn't start (activate) the newly created watcher. |
698 | The C<idle_ns> variant doesn't start (activate) the newly created watcher. |
571 | |
699 | |
572 | =back |
700 | =back |
573 | |
701 | |
… | |
… | |
614 | or return; |
742 | or return; |
615 | |
743 | |
616 | # make the dispatcher handle any outstanding stuff |
744 | # make the dispatcher handle any outstanding stuff |
617 | ... not shown |
745 | ... not shown |
618 | |
746 | |
619 | # create an IO watcher for each and every socket |
747 | # create an I/O watcher for each and every socket |
620 | @snmp_watcher = ( |
748 | @snmp_watcher = ( |
621 | (map { EV::io $_, EV::READ, sub { } } |
749 | (map { EV::io $_, EV::READ, sub { } } |
622 | keys %{ $dispatcher->{_descriptors} }), |
750 | keys %{ $dispatcher->{_descriptors} }), |
623 | |
751 | |
624 | EV::timer +($event->[Net::SNMP::Dispatcher::_ACTIVE] |
752 | EV::timer +($event->[Net::SNMP::Dispatcher::_ACTIVE] |
… | |
… | |
646 | |
774 | |
647 | The C<check_ns> variant doesn't start (activate) the newly created watcher. |
775 | The C<check_ns> variant doesn't start (activate) the newly created watcher. |
648 | |
776 | |
649 | =back |
777 | =back |
650 | |
778 | |
651 | =head3 STAT WATCHERS - did the file attributes just change? |
|
|
652 | |
779 | |
653 | =over 4 |
780 | =head3 FORK WATCHERS - the audacity to resume the event loop after a fork |
654 | |
781 | |
655 | =item $w = EV::stat $path, $interval, $callback |
782 | Fork watchers are called when a C<fork ()> was detected. The invocation |
|
|
783 | is done before the event loop blocks next and before C<check> watchers |
|
|
784 | are being called, and only in the child after the fork. |
656 | |
785 | |
657 | =item $w = EV::stat_ns $path, $interval, $callback |
786 | =over 4 |
658 | |
787 | |
659 | Call the callback when a file status change has been detected on |
788 | =item $w = EV::fork $callback |
660 | C<$path>. The C<$path> does not need to exist, changing from "path exists" |
|
|
661 | to "path does not exist" is a status change like any other. |
|
|
662 | |
789 | |
663 | The C<$interval> is a recommended polling interval for systems where |
790 | =item $w = EV::fork_ns $callback |
664 | OS-supported change notifications don't exist or are not supported. If |
|
|
665 | you use C<0> then an unspecified default is used (which is highly |
|
|
666 | recommended!), which is to be expected to be around five seconds usually. |
|
|
667 | |
791 | |
668 | This watcher type is not meant for massive numbers of stat watchers, |
792 | Call the callback before the event loop is resumed in the child process |
669 | as even with OS-supported change notifications, this can be |
793 | after a fork. |
670 | resource-intensive. |
|
|
671 | |
794 | |
672 | The C<stat_ns> variant doesn't start (activate) the newly created watcher. |
795 | The C<fork_ns> variant doesn't start (activate) the newly created watcher. |
673 | |
796 | |
674 | =item $w->set ($path, $interval) |
|
|
675 | |
|
|
676 | Reconfigures the watcher, see the constructor above for details. Can be |
|
|
677 | called at any time. |
|
|
678 | |
|
|
679 | =item $current_path = $w->path |
|
|
680 | |
|
|
681 | =item $old_path = $w->path ($new_path) |
|
|
682 | |
|
|
683 | Returns the previously set path and optionally set a new one. |
|
|
684 | |
|
|
685 | =item $current_interval = $w->interval |
|
|
686 | |
|
|
687 | =item $old_interval = $w->interval ($new_interval) |
|
|
688 | |
|
|
689 | Returns the previously set interval and optionally set a new one. Can be |
|
|
690 | used to query the actual interval used. |
|
|
691 | |
|
|
692 | =back |
797 | =back |
693 | |
798 | |
|
|
799 | |
|
|
800 | =head1 PERL SIGNALS |
|
|
801 | |
|
|
802 | While Perl signal handling (C<%SIG>) is not affected by EV, the behaviour |
|
|
803 | with EV is as the same as any other C library: Perl-signals will only be |
|
|
804 | handled when Perl runs, which means your signal handler might be invoked |
|
|
805 | only the next time an event callback is invoked. |
|
|
806 | |
|
|
807 | The solution is to use EV signal watchers (see C<EV::signal>), which will |
|
|
808 | ensure proper operations with regards to other event watchers. |
|
|
809 | |
|
|
810 | If you cannot do this for whatever reason, you can also force a watcher |
|
|
811 | to be called on every event loop iteration by installing a C<EV::check> |
|
|
812 | watcher: |
|
|
813 | |
|
|
814 | my $async_check = EV::check sub { }; |
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815 | |
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816 | This ensures that perl shortly gets into control for a short time, and |
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817 | also ensures slower overall operation. |
694 | |
818 | |
695 | =head1 THREADS |
819 | =head1 THREADS |
696 | |
820 | |
697 | Threads are not supported by this module in any way. Perl pseudo-threads |
821 | Threads are not supported by this module in any way. Perl pseudo-threads |
698 | is evil stuff and must die. As soon as Perl gains real threads I will work |
822 | is evil stuff and must die. As soon as Perl gains real threads I will work |
… | |
… | |
720 | our $DIED = sub { |
844 | our $DIED = sub { |
721 | warn "EV: error in callback (ignoring): $@"; |
845 | warn "EV: error in callback (ignoring): $@"; |
722 | }; |
846 | }; |
723 | |
847 | |
724 | default_loop |
848 | default_loop |
725 | or die 'EV: cannot initialise libev backend. bad $ENV{LIBEV_METHODS}?'; |
849 | or die 'EV: cannot initialise libev backend. bad $ENV{LIBEV_FLAGS}?'; |
726 | |
850 | |
727 | 1; |
851 | 1; |
728 | |
852 | |
729 | =head1 SEE ALSO |
853 | =head1 SEE ALSO |
730 | |
854 | |
731 | L<EV::DNS>. |
855 | L<EV::ADNS> (asynchronous dns), L<Glib::EV> (makes Glib/Gtk2 use EV as |
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856 | event loop), L<Coro::EV> (efficient coroutines with EV). |
732 | |
857 | |
733 | =head1 AUTHOR |
858 | =head1 AUTHOR |
734 | |
859 | |
735 | Marc Lehmann <schmorp@schmorp.de> |
860 | Marc Lehmann <schmorp@schmorp.de> |
736 | http://home.schmorp.de/ |
861 | http://home.schmorp.de/ |