… | |
… | |
86 | coroutines, it is mainly useful to compare again C<$Coro::current>, to see |
86 | coroutines, it is mainly useful to compare again C<$Coro::current>, to see |
87 | whether you are running in the main program or not. |
87 | whether you are running in the main program or not. |
88 | |
88 | |
89 | =cut |
89 | =cut |
90 | |
90 | |
91 | $main = new Coro; |
91 | # $main is now being initialised by Coro::State |
92 | |
92 | |
93 | =item $Coro::current |
93 | =item $Coro::current |
94 | |
94 | |
95 | The coroutine object representing the current coroutine (the last |
95 | The coroutine object representing the current coroutine (the last |
96 | coroutine that the Coro scheduler switched to). The initial value is |
96 | coroutine that the Coro scheduler switched to). The initial value is |
97 | C<$main> (of course). |
97 | C<$Coro::main> (of course). |
98 | |
98 | |
99 | This variable is B<strictly> I<read-only>. You can take copies of the |
99 | This variable is B<strictly> I<read-only>. You can take copies of the |
100 | value stored in it and use it as any other coroutine object, but you must |
100 | value stored in it and use it as any other coroutine object, but you must |
101 | not otherwise modify the variable itself. |
101 | not otherwise modify the variable itself. |
102 | |
102 | |
103 | =cut |
103 | =cut |
104 | |
|
|
105 | $main->{desc} = "[main::]"; |
|
|
106 | |
|
|
107 | # maybe some other module used Coro::Specific before... |
|
|
108 | $main->{_specific} = $current->{_specific} |
|
|
109 | if $current; |
|
|
110 | |
|
|
111 | _set_current $main; |
|
|
112 | |
104 | |
113 | sub current() { $current } # [DEPRECATED] |
105 | sub current() { $current } # [DEPRECATED] |
114 | |
106 | |
115 | =item $Coro::idle |
107 | =item $Coro::idle |
116 | |
108 | |
… | |
… | |
157 | for @{ delete $self->{_on_destroy} || [] }; |
149 | for @{ delete $self->{_on_destroy} || [] }; |
158 | } |
150 | } |
159 | |
151 | |
160 | # this coroutine is necessary because a coroutine |
152 | # this coroutine is necessary because a coroutine |
161 | # cannot destroy itself. |
153 | # cannot destroy itself. |
162 | my @destroy; |
154 | our @destroy; |
163 | my $manager; |
155 | our $manager; |
164 | |
156 | |
165 | $manager = new Coro sub { |
157 | $manager = new Coro sub { |
166 | while () { |
158 | while () { |
167 | (shift @destroy)->_cancel |
159 | (shift @destroy)->_cancel |
168 | while @destroy; |
160 | while @destroy; |
… | |
… | |
220 | Similar to C<async>, but uses a coroutine pool, so you should not call |
212 | Similar to C<async>, but uses a coroutine pool, so you should not call |
221 | terminate or join on it (although you are allowed to), and you get a |
213 | terminate or join on it (although you are allowed to), and you get a |
222 | coroutine that might have executed other code already (which can be good |
214 | coroutine that might have executed other code already (which can be good |
223 | or bad :). |
215 | or bad :). |
224 | |
216 | |
225 | On the plus side, this function is faster than creating (and destroying) |
217 | On the plus side, this function is about twice as fast as creating (and |
226 | a completly new coroutine, so if you need a lot of generic coroutines in |
218 | destroying) a completely new coroutine, so if you need a lot of generic |
227 | quick successsion, use C<async_pool>, not C<async>. |
219 | coroutines in quick successsion, use C<async_pool>, not C<async>. |
228 | |
220 | |
229 | The code block is executed in an C<eval> context and a warning will be |
221 | The code block is executed in an C<eval> context and a warning will be |
230 | issued in case of an exception instead of terminating the program, as |
222 | issued in case of an exception instead of terminating the program, as |
231 | C<async> does. As the coroutine is being reused, stuff like C<on_destroy> |
223 | C<async> does. As the coroutine is being reused, stuff like C<on_destroy> |
232 | will not work in the expected way, unless you call terminate or cancel, |
224 | will not work in the expected way, unless you call terminate or cancel, |
… | |
… | |
255 | our $POOL_SIZE = 8; |
247 | our $POOL_SIZE = 8; |
256 | our $POOL_RSS = 16 * 1024; |
248 | our $POOL_RSS = 16 * 1024; |
257 | our @async_pool; |
249 | our @async_pool; |
258 | |
250 | |
259 | sub pool_handler { |
251 | sub pool_handler { |
260 | my $cb; |
|
|
261 | |
|
|
262 | while () { |
252 | while () { |
263 | eval { |
253 | eval { |
264 | while () { |
254 | &{&_pool_handler} while 1; |
265 | _pool_1 $cb; |
|
|
266 | &$cb; |
|
|
267 | _pool_2 $cb; |
|
|
268 | &schedule; |
|
|
269 | } |
|
|
270 | }; |
255 | }; |
271 | |
256 | |
272 | if ($@) { |
|
|
273 | last if $@ eq "\3async_pool terminate\2\n"; |
|
|
274 | warn $@; |
257 | warn $@ if $@; |
275 | } |
|
|
276 | } |
258 | } |
277 | } |
|
|
278 | |
|
|
279 | sub async_pool(&@) { |
|
|
280 | # this is also inlined into the unblock_scheduler |
|
|
281 | my $coro = (pop @async_pool) || new Coro \&pool_handler; |
|
|
282 | |
|
|
283 | $coro->{_invoke} = [@_]; |
|
|
284 | $coro->ready; |
|
|
285 | |
|
|
286 | $coro |
|
|
287 | } |
259 | } |
288 | |
260 | |
289 | =back |
261 | =back |
290 | |
262 | |
291 | =head2 STATIC METHODS |
263 | =head2 STATIC METHODS |
… | |
… | |
313 | >> on that once some event happens, and last you call C<schedule> to put |
285 | >> on that once some event happens, and last you call C<schedule> to put |
314 | yourself to sleep. Note that a lot of things can wake your coroutine up, |
286 | yourself to sleep. Note that a lot of things can wake your coroutine up, |
315 | so you need to check whether the event indeed happened, e.g. by storing the |
287 | so you need to check whether the event indeed happened, e.g. by storing the |
316 | status in a variable. |
288 | status in a variable. |
317 | |
289 | |
318 | The canonical way to wait on external events is this: |
290 | See B<HOW TO WAIT FOR A CALLBACK>, below, for some ways to wait for callbacks. |
319 | |
|
|
320 | { |
|
|
321 | # remember current coroutine |
|
|
322 | my $current = $Coro::current; |
|
|
323 | |
|
|
324 | # register a hypothetical event handler |
|
|
325 | on_event_invoke sub { |
|
|
326 | # wake up sleeping coroutine |
|
|
327 | $current->ready; |
|
|
328 | undef $current; |
|
|
329 | }; |
|
|
330 | |
|
|
331 | # call schedule until event occurred. |
|
|
332 | # in case we are woken up for other reasons |
|
|
333 | # (current still defined), loop. |
|
|
334 | Coro::schedule while $current; |
|
|
335 | } |
|
|
336 | |
291 | |
337 | =item cede |
292 | =item cede |
338 | |
293 | |
339 | "Cede" to other coroutines. This function puts the current coroutine into |
294 | "Cede" to other coroutines. This function puts the current coroutine into |
340 | the ready queue and calls C<schedule>, which has the effect of giving |
295 | the ready queue and calls C<schedule>, which has the effect of giving |
… | |
… | |
365 | program calls this function, there will be some one-time resource leak. |
320 | program calls this function, there will be some one-time resource leak. |
366 | |
321 | |
367 | =cut |
322 | =cut |
368 | |
323 | |
369 | sub terminate { |
324 | sub terminate { |
370 | $current->cancel (@_); |
325 | $current->{_status} = [@_]; |
|
|
326 | push @destroy, $current; |
|
|
327 | $manager->ready; |
|
|
328 | do { &schedule } while 1; |
371 | } |
329 | } |
372 | |
330 | |
373 | sub killall { |
331 | sub killall { |
374 | for (Coro::State::list) { |
332 | for (Coro::State::list) { |
375 | $_->cancel |
333 | $_->cancel |
… | |
… | |
396 | See C<async> and C<Coro::State::new> for additional info about the |
354 | See C<async> and C<Coro::State::new> for additional info about the |
397 | coroutine environment. |
355 | coroutine environment. |
398 | |
356 | |
399 | =cut |
357 | =cut |
400 | |
358 | |
401 | sub _run_coro { |
359 | sub _terminate { |
402 | terminate &{+shift}; |
360 | terminate &{+shift}; |
403 | } |
|
|
404 | |
|
|
405 | sub new { |
|
|
406 | my $class = shift; |
|
|
407 | |
|
|
408 | $class->SUPER::new (\&_run_coro, @_) |
|
|
409 | } |
361 | } |
410 | |
362 | |
411 | =item $success = $coroutine->ready |
363 | =item $success = $coroutine->ready |
412 | |
364 | |
413 | Put the given coroutine into the end of its ready queue (there is one |
365 | Put the given coroutine into the end of its ready queue (there is one |
… | |
… | |
430 | |
382 | |
431 | =cut |
383 | =cut |
432 | |
384 | |
433 | sub cancel { |
385 | sub cancel { |
434 | my $self = shift; |
386 | my $self = shift; |
435 | $self->{_status} = [@_]; |
|
|
436 | |
387 | |
437 | if ($current == $self) { |
388 | if ($current == $self) { |
438 | push @destroy, $self; |
389 | terminate @_; |
439 | $manager->ready; |
|
|
440 | &schedule while 1; |
|
|
441 | } else { |
390 | } else { |
|
|
391 | $self->{_status} = [@_]; |
442 | $self->_cancel; |
392 | $self->_cancel; |
443 | } |
393 | } |
444 | } |
394 | } |
445 | |
395 | |
|
|
396 | =item $coroutine->schedule_to |
|
|
397 | |
|
|
398 | Puts the current coroutine to sleep (like C<Coro::schedule>), but instead |
|
|
399 | of continuing with the next coro from the ready queue, always switch to |
|
|
400 | the given coroutine object (regardless of priority etc.). The readyness |
|
|
401 | state of that coroutine isn't changed. |
|
|
402 | |
|
|
403 | This is an advanced method for special cases - I'd love to hear about any |
|
|
404 | uses for this one. |
|
|
405 | |
|
|
406 | =item $coroutine->cede_to |
|
|
407 | |
|
|
408 | Like C<schedule_to>, but puts the current coroutine into the ready |
|
|
409 | queue. This has the effect of temporarily switching to the given |
|
|
410 | coroutine, and continuing some time later. |
|
|
411 | |
|
|
412 | This is an advanced method for special cases - I'd love to hear about any |
|
|
413 | uses for this one. |
|
|
414 | |
446 | =item $coroutine->throw ([$scalar]) |
415 | =item $coroutine->throw ([$scalar]) |
447 | |
416 | |
448 | If C<$throw> is specified and defined, it will be thrown as an exception |
417 | If C<$throw> is specified and defined, it will be thrown as an exception |
449 | inside the coroutine at the next convenient point in time (usually after |
418 | inside the coroutine at the next convenient point in time. Otherwise |
450 | it gains control at the next schedule/transfer/cede). Otherwise clears the |
|
|
451 | exception object. |
419 | clears the exception object. |
|
|
420 | |
|
|
421 | Coro will check for the exception each time a schedule-like-function |
|
|
422 | returns, i.e. after each C<schedule>, C<cede>, C<< Coro::Semaphore->down |
|
|
423 | >>, C<< Coro::Handle->readable >> and so on. Most of these functions |
|
|
424 | detect this case and return early in case an exception is pending. |
452 | |
425 | |
453 | The exception object will be thrown "as is" with the specified scalar in |
426 | The exception object will be thrown "as is" with the specified scalar in |
454 | C<$@>, i.e. if it is a string, no line number or newline will be appended |
427 | C<$@>, i.e. if it is a string, no line number or newline will be appended |
455 | (unlike with C<die>). |
428 | (unlike with C<die>). |
456 | |
429 | |
… | |
… | |
636 | # return immediately and can be reused) and because we cannot cede |
609 | # return immediately and can be reused) and because we cannot cede |
637 | # inside an event callback. |
610 | # inside an event callback. |
638 | our $unblock_scheduler = new Coro sub { |
611 | our $unblock_scheduler = new Coro sub { |
639 | while () { |
612 | while () { |
640 | while (my $cb = pop @unblock_queue) { |
613 | while (my $cb = pop @unblock_queue) { |
641 | # this is an inlined copy of async_pool |
614 | &async_pool (@$cb); |
642 | my $coro = (pop @async_pool) || new Coro \&pool_handler; |
|
|
643 | |
615 | |
644 | $coro->{_invoke} = $cb; |
|
|
645 | $coro->ready; |
|
|
646 | cede; # for short-lived callbacks, this reduces pressure on the coro pool |
616 | # for short-lived callbacks, this reduces pressure on the coro pool |
|
|
617 | # as the chance is very high that the async_poll coro will be back |
|
|
618 | # in the idle state when cede returns |
|
|
619 | cede; |
647 | } |
620 | } |
648 | schedule; # sleep well |
621 | schedule; # sleep well |
649 | } |
622 | } |
650 | }; |
623 | }; |
651 | $unblock_scheduler->{desc} = "[unblock_sub scheduler]"; |
624 | $unblock_scheduler->{desc} = "[unblock_sub scheduler]"; |
… | |
… | |
657 | unshift @unblock_queue, [$cb, @_]; |
630 | unshift @unblock_queue, [$cb, @_]; |
658 | $unblock_scheduler->ready; |
631 | $unblock_scheduler->ready; |
659 | } |
632 | } |
660 | } |
633 | } |
661 | |
634 | |
|
|
635 | =item $cb = Coro::rouse_cb |
|
|
636 | |
|
|
637 | Create and return a "rouse callback". That's a code reference that, when |
|
|
638 | called, will save its arguments and notify the owner coroutine of the |
|
|
639 | callback. |
|
|
640 | |
|
|
641 | See the next function. |
|
|
642 | |
|
|
643 | =item @args = Coro::rouse_wait [$cb] |
|
|
644 | |
|
|
645 | Wait for the specified rouse callback (or the last one tht was created in |
|
|
646 | this coroutine). |
|
|
647 | |
|
|
648 | As soon as the callback is invoked (or when the calback was invoked before |
|
|
649 | C<rouse_wait>), it will return a copy of the arguments originally passed |
|
|
650 | to the rouse callback. |
|
|
651 | |
|
|
652 | See the section B<HOW TO WAIT FOR A CALLBACK> for an actual usage example. |
|
|
653 | |
662 | =back |
654 | =back |
663 | |
655 | |
664 | =cut |
656 | =cut |
665 | |
657 | |
666 | 1; |
658 | 1; |
667 | |
659 | |
|
|
660 | =head1 HOW TO WAIT FOR A CALLBACK |
|
|
661 | |
|
|
662 | It is very common for a coroutine to wait for some callback to be |
|
|
663 | called. This occurs naturally when you use coroutines in an otherwise |
|
|
664 | event-based program, or when you use event-based libraries. |
|
|
665 | |
|
|
666 | These typically register a callback for some event, and call that callback |
|
|
667 | when the event occured. In a coroutine, however, you typically want to |
|
|
668 | just wait for the event, simplyifying things. |
|
|
669 | |
|
|
670 | For example C<< AnyEvent->child >> registers a callback to be called when |
|
|
671 | a specific child has exited: |
|
|
672 | |
|
|
673 | my $child_watcher = AnyEvent->child (pid => $pid, cb => sub { ... }); |
|
|
674 | |
|
|
675 | But from withina coroutine, you often just want to write this: |
|
|
676 | |
|
|
677 | my $status = wait_for_child $pid; |
|
|
678 | |
|
|
679 | Coro offers two functions specifically designed to make this easy, |
|
|
680 | C<Coro::rouse_cb> and C<Coro::rouse_wait>. |
|
|
681 | |
|
|
682 | The first function, C<rouse_cb>, generates and returns a callback that, |
|
|
683 | when invoked, will save it's arguments and notify the coroutine that |
|
|
684 | created the callback. |
|
|
685 | |
|
|
686 | The second function, C<rouse_wait>, waits for the callback to be called |
|
|
687 | (by calling C<schedule> to go to sleep) and returns the arguments |
|
|
688 | originally passed to the callback. |
|
|
689 | |
|
|
690 | Using these functions, it becomes easy to write the C<wait_for_child> |
|
|
691 | function mentioned above: |
|
|
692 | |
|
|
693 | sub wait_for_child($) { |
|
|
694 | my ($pid) = @_; |
|
|
695 | |
|
|
696 | my $watcher = AnyEvent->child (pid => $pid, cb => Coro::rouse_cb); |
|
|
697 | |
|
|
698 | my ($rpid, $rstatus) = Coro::rouse_wait; |
|
|
699 | $rstatus |
|
|
700 | } |
|
|
701 | |
|
|
702 | In the case where C<rouse_cb> and C<rouse_wait> are not flexible enough, |
|
|
703 | you can roll your own, using C<schedule>: |
|
|
704 | |
|
|
705 | sub wait_for_child($) { |
|
|
706 | my ($pid) = @_; |
|
|
707 | |
|
|
708 | # store the current coroutine in $current, |
|
|
709 | # and provide result variables for the closure passed to ->child |
|
|
710 | my $current = $Coro::current; |
|
|
711 | my ($done, $rstatus); |
|
|
712 | |
|
|
713 | # pass a closure to ->child |
|
|
714 | my $watcher = AnyEvent->child (pid => $pid, cb => sub { |
|
|
715 | $rstatus = $_[1]; # remember rstatus |
|
|
716 | $done = 1; # mark $rstatus as valud |
|
|
717 | }); |
|
|
718 | |
|
|
719 | # wait until the closure has been called |
|
|
720 | schedule while !$done; |
|
|
721 | |
|
|
722 | $rstatus |
|
|
723 | } |
|
|
724 | |
|
|
725 | |
668 | =head1 BUGS/LIMITATIONS |
726 | =head1 BUGS/LIMITATIONS |
669 | |
727 | |
670 | =over 4 |
728 | =over 4 |
|
|
729 | |
|
|
730 | =item fork with pthread backend |
|
|
731 | |
|
|
732 | When Coro is compiled using the pthread backend (which isn't recommended |
|
|
733 | but required on many BSDs as their libcs are completely broken), then |
|
|
734 | coroutines will not survive a fork. There is no known workaround except to |
|
|
735 | fix your libc and use a saner backend. |
671 | |
736 | |
672 | =item perl process emulation ("threads") |
737 | =item perl process emulation ("threads") |
673 | |
738 | |
674 | This module is not perl-pseudo-thread-safe. You should only ever use this |
739 | This module is not perl-pseudo-thread-safe. You should only ever use this |
675 | module from the same thread (this requirement might be removed in the |
740 | module from the same thread (this requirement might be removed in the |
… | |
… | |
681 | =item coroutine switching not signal safe |
746 | =item coroutine switching not signal safe |
682 | |
747 | |
683 | You must not switch to another coroutine from within a signal handler |
748 | You must not switch to another coroutine from within a signal handler |
684 | (only relevant with %SIG - most event libraries provide safe signals). |
749 | (only relevant with %SIG - most event libraries provide safe signals). |
685 | |
750 | |
686 | That means you I<MUST NOT> call any fucntion that might "block" the |
751 | That means you I<MUST NOT> call any function that might "block" the |
687 | current coroutine - C<cede>, C<schedule> C<< Coro::Semaphore->down >> or |
752 | current coroutine - C<cede>, C<schedule> C<< Coro::Semaphore->down >> or |
688 | anything that calls those. Everything else, including calling C<ready>, |
753 | anything that calls those. Everything else, including calling C<ready>, |
689 | works. |
754 | works. |
690 | |
755 | |
691 | =back |
756 | =back |