… | |
… | |
16 | cede; # yield to coroutine |
16 | cede; # yield to coroutine |
17 | print "3\n"; |
17 | print "3\n"; |
18 | cede; # and again |
18 | cede; # and again |
19 | |
19 | |
20 | # use locking |
20 | # use locking |
|
|
21 | use Coro::Semaphore; |
21 | my $lock = new Coro::Semaphore; |
22 | my $lock = new Coro::Semaphore; |
22 | my $locked; |
23 | my $locked; |
23 | |
24 | |
24 | $lock->down; |
25 | $lock->down; |
25 | $locked = 1; |
26 | $locked = 1; |
… | |
… | |
55 | |
56 | |
56 | =cut |
57 | =cut |
57 | |
58 | |
58 | package Coro; |
59 | package Coro; |
59 | |
60 | |
60 | use strict; |
61 | use strict qw(vars subs); |
61 | no warnings "uninitialized"; |
62 | no warnings "uninitialized"; |
62 | |
63 | |
63 | use Coro::State; |
64 | use Coro::State; |
64 | |
65 | |
65 | use base qw(Coro::State Exporter); |
66 | use base qw(Coro::State Exporter); |
66 | |
67 | |
67 | our $idle; # idle handler |
68 | our $idle; # idle handler |
68 | our $main; # main coroutine |
69 | our $main; # main coroutine |
69 | our $current; # current coroutine |
70 | our $current; # current coroutine |
70 | |
71 | |
71 | our $VERSION = 4.745; |
72 | our $VERSION = "5.0"; |
72 | |
73 | |
73 | our @EXPORT = qw(async async_pool cede schedule terminate current unblock_sub); |
74 | our @EXPORT = qw(async async_pool cede schedule terminate current unblock_sub); |
74 | our %EXPORT_TAGS = ( |
75 | our %EXPORT_TAGS = ( |
75 | prio => [qw(PRIO_MAX PRIO_HIGH PRIO_NORMAL PRIO_LOW PRIO_IDLE PRIO_MIN)], |
76 | prio => [qw(PRIO_MAX PRIO_HIGH PRIO_NORMAL PRIO_LOW PRIO_IDLE PRIO_MIN)], |
76 | ); |
77 | ); |
… | |
… | |
81 | =item $Coro::main |
82 | =item $Coro::main |
82 | |
83 | |
83 | This variable stores the coroutine object that represents the main |
84 | This variable stores the coroutine object that represents the main |
84 | program. While you cna C<ready> it and do most other things you can do to |
85 | program. While you cna C<ready> it and do most other things you can do to |
85 | coroutines, it is mainly useful to compare again C<$Coro::current>, to see |
86 | coroutines, it is mainly useful to compare again C<$Coro::current>, to see |
86 | wether you are running in the main program or not. |
87 | whether you are running in the main program or not. |
87 | |
88 | |
88 | =cut |
89 | =cut |
89 | |
90 | |
90 | $main = new Coro; |
91 | # $main is now being initialised by Coro::State |
91 | |
92 | |
92 | =item $Coro::current |
93 | =item $Coro::current |
93 | |
94 | |
94 | The coroutine object representing the current coroutine (the last |
95 | The coroutine object representing the current coroutine (the last |
95 | coroutine that the Coro scheduler switched to). The initial value is |
96 | coroutine that the Coro scheduler switched to). The initial value is |
96 | C<$main> (of course). |
97 | C<$Coro::main> (of course). |
97 | |
98 | |
98 | 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 |
99 | 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 |
100 | not otherwise modify the variable itself. |
101 | not otherwise modify the variable itself. |
101 | |
102 | |
102 | =cut |
103 | =cut |
103 | |
|
|
104 | $main->{desc} = "[main::]"; |
|
|
105 | |
|
|
106 | # maybe some other module used Coro::Specific before... |
|
|
107 | $main->{_specific} = $current->{_specific} |
|
|
108 | if $current; |
|
|
109 | |
|
|
110 | _set_current $main; |
|
|
111 | |
104 | |
112 | sub current() { $current } # [DEPRECATED] |
105 | sub current() { $current } # [DEPRECATED] |
113 | |
106 | |
114 | =item $Coro::idle |
107 | =item $Coro::idle |
115 | |
108 | |
… | |
… | |
142 | $idle = sub { |
135 | $idle = sub { |
143 | require Carp; |
136 | require Carp; |
144 | Carp::croak ("FATAL: deadlock detected"); |
137 | Carp::croak ("FATAL: deadlock detected"); |
145 | }; |
138 | }; |
146 | |
139 | |
147 | sub _cancel { |
|
|
148 | my ($self) = @_; |
|
|
149 | |
|
|
150 | # free coroutine data and mark as destructed |
|
|
151 | $self->_destroy |
|
|
152 | or return; |
|
|
153 | |
|
|
154 | # call all destruction callbacks |
|
|
155 | $_->(@{$self->{_status}}) |
|
|
156 | for @{(delete $self->{_on_destroy}) || []}; |
|
|
157 | } |
|
|
158 | |
|
|
159 | # this coroutine is necessary because a coroutine |
140 | # this coroutine is necessary because a coroutine |
160 | # cannot destroy itself. |
141 | # cannot destroy itself. |
161 | my @destroy; |
142 | our @destroy; |
162 | my $manager; |
143 | our $manager; |
163 | |
144 | |
164 | $manager = new Coro sub { |
145 | $manager = new Coro sub { |
165 | while () { |
146 | while () { |
166 | (shift @destroy)->_cancel |
147 | Coro::_cancel shift @destroy |
167 | while @destroy; |
148 | while @destroy; |
168 | |
149 | |
169 | &schedule; |
150 | &schedule; |
170 | } |
151 | } |
171 | }; |
152 | }; |
172 | $manager->desc ("[coro manager]"); |
153 | $manager->{desc} = "[coro manager]"; |
173 | $manager->prio (PRIO_MAX); |
154 | $manager->prio (PRIO_MAX); |
174 | |
155 | |
175 | =back |
156 | =back |
176 | |
157 | |
177 | =head2 SIMPLE COROUTINE CREATION |
158 | =head2 SIMPLE COROUTINE CREATION |
… | |
… | |
219 | Similar to C<async>, but uses a coroutine pool, so you should not call |
200 | Similar to C<async>, but uses a coroutine pool, so you should not call |
220 | terminate or join on it (although you are allowed to), and you get a |
201 | terminate or join on it (although you are allowed to), and you get a |
221 | coroutine that might have executed other code already (which can be good |
202 | coroutine that might have executed other code already (which can be good |
222 | or bad :). |
203 | or bad :). |
223 | |
204 | |
224 | On the plus side, this function is faster than creating (and destroying) |
205 | On the plus side, this function is about twice as fast as creating (and |
225 | a completely new coroutine, so if you need a lot of generic coroutines in |
206 | destroying) a completely new coroutine, so if you need a lot of generic |
226 | quick successsion, use C<async_pool>, not C<async>. |
207 | coroutines in quick successsion, use C<async_pool>, not C<async>. |
227 | |
208 | |
228 | The code block is executed in an C<eval> context and a warning will be |
209 | The code block is executed in an C<eval> context and a warning will be |
229 | issued in case of an exception instead of terminating the program, as |
210 | issued in case of an exception instead of terminating the program, as |
230 | C<async> does. As the coroutine is being reused, stuff like C<on_destroy> |
211 | C<async> does. As the coroutine is being reused, stuff like C<on_destroy> |
231 | will not work in the expected way, unless you call terminate or cancel, |
212 | will not work in the expected way, unless you call terminate or cancel, |
… | |
… | |
234 | |
215 | |
235 | The priority will be reset to C<0> after each run, tracing will be |
216 | The priority will be reset to C<0> after each run, tracing will be |
236 | disabled, the description will be reset and the default output filehandle |
217 | disabled, the description will be reset and the default output filehandle |
237 | gets restored, so you can change all these. Otherwise the coroutine will |
218 | gets restored, so you can change all these. Otherwise the coroutine will |
238 | be re-used "as-is": most notably if you change other per-coroutine global |
219 | be re-used "as-is": most notably if you change other per-coroutine global |
239 | stuff such as C<$/> you I<must needs> to revert that change, which is most |
220 | stuff such as C<$/> you I<must needs> revert that change, which is most |
240 | simply done by using local as in: C< local $/ >. |
221 | simply done by using local as in: C<< local $/ >>. |
241 | |
222 | |
242 | The pool size is limited to C<8> idle coroutines (this can be adjusted by |
223 | The idle pool size is limited to C<8> idle coroutines (this can be |
243 | changing $Coro::POOL_SIZE), and there can be as many non-idle coros as |
224 | adjusted by changing $Coro::POOL_SIZE), but there can be as many non-idle |
244 | required. |
225 | coros as required. |
245 | |
226 | |
246 | If you are concerned about pooled coroutines growing a lot because a |
227 | If you are concerned about pooled coroutines growing a lot because a |
247 | single C<async_pool> used a lot of stackspace you can e.g. C<async_pool |
228 | single C<async_pool> used a lot of stackspace you can e.g. C<async_pool |
248 | { terminate }> once per second or so to slowly replenish the pool. In |
229 | { terminate }> once per second or so to slowly replenish the pool. In |
249 | addition to that, when the stacks used by a handler grows larger than 16kb |
230 | addition to that, when the stacks used by a handler grows larger than 16kb |
… | |
… | |
254 | our $POOL_SIZE = 8; |
235 | our $POOL_SIZE = 8; |
255 | our $POOL_RSS = 16 * 1024; |
236 | our $POOL_RSS = 16 * 1024; |
256 | our @async_pool; |
237 | our @async_pool; |
257 | |
238 | |
258 | sub pool_handler { |
239 | sub pool_handler { |
259 | my $cb; |
|
|
260 | |
|
|
261 | while () { |
240 | while () { |
262 | eval { |
241 | eval { |
263 | while () { |
242 | &{&_pool_handler} while 1; |
264 | _pool_1 $cb; |
|
|
265 | &$cb; |
|
|
266 | _pool_2 $cb; |
|
|
267 | &schedule; |
|
|
268 | } |
|
|
269 | }; |
243 | }; |
270 | |
244 | |
271 | if ($@) { |
|
|
272 | last if $@ eq "\3async_pool terminate\2\n"; |
|
|
273 | warn $@; |
245 | warn $@ if $@; |
274 | } |
|
|
275 | } |
246 | } |
276 | } |
|
|
277 | |
|
|
278 | sub async_pool(&@) { |
|
|
279 | # this is also inlined into the unlock_scheduler |
|
|
280 | my $coro = (pop @async_pool) || new Coro \&pool_handler; |
|
|
281 | |
|
|
282 | $coro->{_invoke} = [@_]; |
|
|
283 | $coro->ready; |
|
|
284 | |
|
|
285 | $coro |
|
|
286 | } |
247 | } |
287 | |
248 | |
288 | =back |
249 | =back |
289 | |
250 | |
290 | =head2 STATIC METHODS |
251 | =head2 STATIC METHODS |
… | |
… | |
309 | This makes C<schedule> I<the> generic method to use to block the current |
270 | This makes C<schedule> I<the> generic method to use to block the current |
310 | coroutine and wait for events: first you remember the current coroutine in |
271 | coroutine and wait for events: first you remember the current coroutine in |
311 | a variable, then arrange for some callback of yours to call C<< ->ready |
272 | a variable, then arrange for some callback of yours to call C<< ->ready |
312 | >> on that once some event happens, and last you call C<schedule> to put |
273 | >> on that once some event happens, and last you call C<schedule> to put |
313 | yourself to sleep. Note that a lot of things can wake your coroutine up, |
274 | yourself to sleep. Note that a lot of things can wake your coroutine up, |
314 | so you need to check wether the event indeed happened, e.g. by storing the |
275 | so you need to check whether the event indeed happened, e.g. by storing the |
315 | status in a variable. |
276 | status in a variable. |
316 | |
277 | |
317 | The canonical way to wait on external events is this: |
278 | See B<HOW TO WAIT FOR A CALLBACK>, below, for some ways to wait for callbacks. |
318 | |
|
|
319 | { |
|
|
320 | # remember current coroutine |
|
|
321 | my $current = $Coro::current; |
|
|
322 | |
|
|
323 | # register a hypothetical event handler |
|
|
324 | on_event_invoke sub { |
|
|
325 | # wake up sleeping coroutine |
|
|
326 | $current->ready; |
|
|
327 | undef $current; |
|
|
328 | }; |
|
|
329 | |
|
|
330 | # call schedule until event occurred. |
|
|
331 | # in case we are woken up for other reasons |
|
|
332 | # (current still defined), loop. |
|
|
333 | Coro::schedule while $current; |
|
|
334 | } |
|
|
335 | |
279 | |
336 | =item cede |
280 | =item cede |
337 | |
281 | |
338 | "Cede" to other coroutines. This function puts the current coroutine into |
282 | "Cede" to other coroutines. This function puts the current coroutine into |
339 | the ready queue and calls C<schedule>, which has the effect of giving |
283 | the ready queue and calls C<schedule>, which has the effect of giving |
… | |
… | |
358 | Kills/terminates/cancels all coroutines except the currently running |
302 | Kills/terminates/cancels all coroutines except the currently running |
359 | one. This is useful after a fork, either in the child or the parent, as |
303 | one. This is useful after a fork, either in the child or the parent, as |
360 | usually only one of them should inherit the running coroutines. |
304 | usually only one of them should inherit the running coroutines. |
361 | |
305 | |
362 | Note that while this will try to free some of the main programs resources, |
306 | Note that while this will try to free some of the main programs resources, |
363 | you cnanot free all of them, so if a coroutine that is not the main |
307 | you cannot free all of them, so if a coroutine that is not the main |
364 | program calls this function, there will be some one-time resource leak. |
308 | program calls this function, there will be some one-time resource leak. |
365 | |
309 | |
366 | =cut |
310 | =cut |
367 | |
|
|
368 | sub terminate { |
|
|
369 | $current->cancel (@_); |
|
|
370 | } |
|
|
371 | |
311 | |
372 | sub killall { |
312 | sub killall { |
373 | for (Coro::State::list) { |
313 | for (Coro::State::list) { |
374 | $_->cancel |
314 | $_->cancel |
375 | if $_ != $current && UNIVERSAL::isa $_, "Coro"; |
315 | if $_ != $current && UNIVERSAL::isa $_, "Coro"; |
… | |
… | |
395 | See C<async> and C<Coro::State::new> for additional info about the |
335 | See C<async> and C<Coro::State::new> for additional info about the |
396 | coroutine environment. |
336 | coroutine environment. |
397 | |
337 | |
398 | =cut |
338 | =cut |
399 | |
339 | |
400 | sub _run_coro { |
340 | sub _terminate { |
401 | terminate &{+shift}; |
341 | terminate &{+shift}; |
402 | } |
|
|
403 | |
|
|
404 | sub new { |
|
|
405 | my $class = shift; |
|
|
406 | |
|
|
407 | $class->SUPER::new (\&_run_coro, @_) |
|
|
408 | } |
342 | } |
409 | |
343 | |
410 | =item $success = $coroutine->ready |
344 | =item $success = $coroutine->ready |
411 | |
345 | |
412 | Put the given coroutine into the end of its ready queue (there is one |
346 | Put the given coroutine into the end of its ready queue (there is one |
… | |
… | |
417 | once all the coroutines of higher priority and all coroutines of the same |
351 | once all the coroutines of higher priority and all coroutines of the same |
418 | priority that were put into the ready queue earlier have been resumed. |
352 | priority that were put into the ready queue earlier have been resumed. |
419 | |
353 | |
420 | =item $is_ready = $coroutine->is_ready |
354 | =item $is_ready = $coroutine->is_ready |
421 | |
355 | |
422 | Return wether the coroutine is currently the ready queue or not, |
356 | Return whether the coroutine is currently the ready queue or not, |
423 | |
357 | |
424 | =item $coroutine->cancel (arg...) |
358 | =item $coroutine->cancel (arg...) |
425 | |
359 | |
426 | Terminates the given coroutine and makes it return the given arguments as |
360 | Terminates the given coroutine and makes it return the given arguments as |
427 | status (default: the empty list). Never returns if the coroutine is the |
361 | status (default: the empty list). Never returns if the coroutine is the |
… | |
… | |
429 | |
363 | |
430 | =cut |
364 | =cut |
431 | |
365 | |
432 | sub cancel { |
366 | sub cancel { |
433 | my $self = shift; |
367 | my $self = shift; |
434 | $self->{_status} = [@_]; |
|
|
435 | |
368 | |
436 | if ($current == $self) { |
369 | if ($current == $self) { |
437 | push @destroy, $self; |
370 | terminate @_; |
438 | $manager->ready; |
|
|
439 | &schedule while 1; |
|
|
440 | } else { |
371 | } else { |
|
|
372 | $self->{_status} = [@_]; |
441 | $self->_cancel; |
373 | $self->_cancel; |
442 | } |
374 | } |
443 | } |
375 | } |
|
|
376 | |
|
|
377 | =item $coroutine->schedule_to |
|
|
378 | |
|
|
379 | Puts the current coroutine to sleep (like C<Coro::schedule>), but instead |
|
|
380 | of continuing with the next coro from the ready queue, always switch to |
|
|
381 | the given coroutine object (regardless of priority etc.). The readyness |
|
|
382 | state of that coroutine isn't changed. |
|
|
383 | |
|
|
384 | This is an advanced method for special cases - I'd love to hear about any |
|
|
385 | uses for this one. |
|
|
386 | |
|
|
387 | =item $coroutine->cede_to |
|
|
388 | |
|
|
389 | Like C<schedule_to>, but puts the current coroutine into the ready |
|
|
390 | queue. This has the effect of temporarily switching to the given |
|
|
391 | coroutine, and continuing some time later. |
|
|
392 | |
|
|
393 | This is an advanced method for special cases - I'd love to hear about any |
|
|
394 | uses for this one. |
|
|
395 | |
|
|
396 | =item $coroutine->throw ([$scalar]) |
|
|
397 | |
|
|
398 | If C<$throw> is specified and defined, it will be thrown as an exception |
|
|
399 | inside the coroutine at the next convenient point in time. Otherwise |
|
|
400 | clears the exception object. |
|
|
401 | |
|
|
402 | Coro will check for the exception each time a schedule-like-function |
|
|
403 | returns, i.e. after each C<schedule>, C<cede>, C<< Coro::Semaphore->down |
|
|
404 | >>, C<< Coro::Handle->readable >> and so on. Most of these functions |
|
|
405 | detect this case and return early in case an exception is pending. |
|
|
406 | |
|
|
407 | The exception object will be thrown "as is" with the specified scalar in |
|
|
408 | C<$@>, i.e. if it is a string, no line number or newline will be appended |
|
|
409 | (unlike with C<die>). |
|
|
410 | |
|
|
411 | This can be used as a softer means than C<cancel> to ask a coroutine to |
|
|
412 | end itself, although there is no guarantee that the exception will lead to |
|
|
413 | termination, and if the exception isn't caught it might well end the whole |
|
|
414 | program. |
|
|
415 | |
|
|
416 | You might also think of C<throw> as being the moral equivalent of |
|
|
417 | C<kill>ing a coroutine with a signal (in this case, a scalar). |
444 | |
418 | |
445 | =item $coroutine->join |
419 | =item $coroutine->join |
446 | |
420 | |
447 | Wait until the coroutine terminates and return any values given to the |
421 | Wait until the coroutine terminates and return any values given to the |
448 | C<terminate> or C<cancel> functions. C<join> can be called concurrently |
422 | C<terminate> or C<cancel> functions. C<join> can be called concurrently |
… | |
… | |
510 | higher values mean lower priority, just as in unix). |
484 | higher values mean lower priority, just as in unix). |
511 | |
485 | |
512 | =item $olddesc = $coroutine->desc ($newdesc) |
486 | =item $olddesc = $coroutine->desc ($newdesc) |
513 | |
487 | |
514 | Sets (or gets in case the argument is missing) the description for this |
488 | Sets (or gets in case the argument is missing) the description for this |
515 | coroutine. This is just a free-form string you can associate with a coroutine. |
489 | coroutine. This is just a free-form string you can associate with a |
|
|
490 | coroutine. |
516 | |
491 | |
517 | This method simply sets the C<< $coroutine->{desc} >> member to the given string. You |
492 | This method simply sets the C<< $coroutine->{desc} >> member to the given |
518 | can modify this member directly if you wish. |
493 | string. You can modify this member directly if you wish. |
519 | |
|
|
520 | =item $coroutine->throw ([$scalar]) |
|
|
521 | |
|
|
522 | If C<$throw> is specified and defined, it will be thrown as an exception |
|
|
523 | inside the coroutine at the next convinient point in time (usually after |
|
|
524 | it gains control at the next schedule/transfer/cede). Otherwise clears the |
|
|
525 | exception object. |
|
|
526 | |
|
|
527 | The exception object will be thrown "as is" with the specified scalar in |
|
|
528 | C<$@>, i.e. if it is a string, no line number or newline will be appended |
|
|
529 | (unlike with C<die>). |
|
|
530 | |
|
|
531 | This can be used as a softer means than C<cancel> to ask a coroutine to |
|
|
532 | end itself, although there is no guarentee that the exception will lead to |
|
|
533 | termination, and if the exception isn't caught it might well end the whole |
|
|
534 | program. |
|
|
535 | |
494 | |
536 | =cut |
495 | =cut |
537 | |
496 | |
538 | sub desc { |
497 | sub desc { |
539 | my $old = $_[0]{desc}; |
498 | my $old = $_[0]{desc}; |
… | |
… | |
631 | # return immediately and can be reused) and because we cannot cede |
590 | # return immediately and can be reused) and because we cannot cede |
632 | # inside an event callback. |
591 | # inside an event callback. |
633 | our $unblock_scheduler = new Coro sub { |
592 | our $unblock_scheduler = new Coro sub { |
634 | while () { |
593 | while () { |
635 | while (my $cb = pop @unblock_queue) { |
594 | while (my $cb = pop @unblock_queue) { |
636 | # this is an inlined copy of async_pool |
595 | &async_pool (@$cb); |
637 | my $coro = (pop @async_pool) || new Coro \&pool_handler; |
|
|
638 | |
596 | |
639 | $coro->{_invoke} = $cb; |
|
|
640 | $coro->ready; |
|
|
641 | cede; # for short-lived callbacks, this reduces pressure on the coro pool |
597 | # for short-lived callbacks, this reduces pressure on the coro pool |
|
|
598 | # as the chance is very high that the async_poll coro will be back |
|
|
599 | # in the idle state when cede returns |
|
|
600 | cede; |
642 | } |
601 | } |
643 | schedule; # sleep well |
602 | schedule; # sleep well |
644 | } |
603 | } |
645 | }; |
604 | }; |
646 | $unblock_scheduler->desc ("[unblock_sub scheduler]"); |
605 | $unblock_scheduler->{desc} = "[unblock_sub scheduler]"; |
647 | |
606 | |
648 | sub unblock_sub(&) { |
607 | sub unblock_sub(&) { |
649 | my $cb = shift; |
608 | my $cb = shift; |
650 | |
609 | |
651 | sub { |
610 | sub { |
652 | unshift @unblock_queue, [$cb, @_]; |
611 | unshift @unblock_queue, [$cb, @_]; |
653 | $unblock_scheduler->ready; |
612 | $unblock_scheduler->ready; |
654 | } |
613 | } |
655 | } |
614 | } |
656 | |
615 | |
|
|
616 | =item $cb = Coro::rouse_cb |
|
|
617 | |
|
|
618 | Create and return a "rouse callback". That's a code reference that, when |
|
|
619 | called, will save its arguments and notify the owner coroutine of the |
|
|
620 | callback. |
|
|
621 | |
|
|
622 | See the next function. |
|
|
623 | |
|
|
624 | =item @args = Coro::rouse_wait [$cb] |
|
|
625 | |
|
|
626 | Wait for the specified rouse callback (or the last one tht was created in |
|
|
627 | this coroutine). |
|
|
628 | |
|
|
629 | As soon as the callback is invoked (or when the calback was invoked before |
|
|
630 | C<rouse_wait>), it will return a copy of the arguments originally passed |
|
|
631 | to the rouse callback. |
|
|
632 | |
|
|
633 | See the section B<HOW TO WAIT FOR A CALLBACK> for an actual usage example. |
|
|
634 | |
657 | =back |
635 | =back |
658 | |
636 | |
659 | =cut |
637 | =cut |
660 | |
638 | |
661 | 1; |
639 | 1; |
662 | |
640 | |
|
|
641 | =head1 HOW TO WAIT FOR A CALLBACK |
|
|
642 | |
|
|
643 | It is very common for a coroutine to wait for some callback to be |
|
|
644 | called. This occurs naturally when you use coroutines in an otherwise |
|
|
645 | event-based program, or when you use event-based libraries. |
|
|
646 | |
|
|
647 | These typically register a callback for some event, and call that callback |
|
|
648 | when the event occured. In a coroutine, however, you typically want to |
|
|
649 | just wait for the event, simplyifying things. |
|
|
650 | |
|
|
651 | For example C<< AnyEvent->child >> registers a callback to be called when |
|
|
652 | a specific child has exited: |
|
|
653 | |
|
|
654 | my $child_watcher = AnyEvent->child (pid => $pid, cb => sub { ... }); |
|
|
655 | |
|
|
656 | But from withina coroutine, you often just want to write this: |
|
|
657 | |
|
|
658 | my $status = wait_for_child $pid; |
|
|
659 | |
|
|
660 | Coro offers two functions specifically designed to make this easy, |
|
|
661 | C<Coro::rouse_cb> and C<Coro::rouse_wait>. |
|
|
662 | |
|
|
663 | The first function, C<rouse_cb>, generates and returns a callback that, |
|
|
664 | when invoked, will save it's arguments and notify the coroutine that |
|
|
665 | created the callback. |
|
|
666 | |
|
|
667 | The second function, C<rouse_wait>, waits for the callback to be called |
|
|
668 | (by calling C<schedule> to go to sleep) and returns the arguments |
|
|
669 | originally passed to the callback. |
|
|
670 | |
|
|
671 | Using these functions, it becomes easy to write the C<wait_for_child> |
|
|
672 | function mentioned above: |
|
|
673 | |
|
|
674 | sub wait_for_child($) { |
|
|
675 | my ($pid) = @_; |
|
|
676 | |
|
|
677 | my $watcher = AnyEvent->child (pid => $pid, cb => Coro::rouse_cb); |
|
|
678 | |
|
|
679 | my ($rpid, $rstatus) = Coro::rouse_wait; |
|
|
680 | $rstatus |
|
|
681 | } |
|
|
682 | |
|
|
683 | In the case where C<rouse_cb> and C<rouse_wait> are not flexible enough, |
|
|
684 | you can roll your own, using C<schedule>: |
|
|
685 | |
|
|
686 | sub wait_for_child($) { |
|
|
687 | my ($pid) = @_; |
|
|
688 | |
|
|
689 | # store the current coroutine in $current, |
|
|
690 | # and provide result variables for the closure passed to ->child |
|
|
691 | my $current = $Coro::current; |
|
|
692 | my ($done, $rstatus); |
|
|
693 | |
|
|
694 | # pass a closure to ->child |
|
|
695 | my $watcher = AnyEvent->child (pid => $pid, cb => sub { |
|
|
696 | $rstatus = $_[1]; # remember rstatus |
|
|
697 | $done = 1; # mark $rstatus as valud |
|
|
698 | }); |
|
|
699 | |
|
|
700 | # wait until the closure has been called |
|
|
701 | schedule while !$done; |
|
|
702 | |
|
|
703 | $rstatus |
|
|
704 | } |
|
|
705 | |
|
|
706 | |
663 | =head1 BUGS/LIMITATIONS |
707 | =head1 BUGS/LIMITATIONS |
|
|
708 | |
|
|
709 | =over 4 |
|
|
710 | |
|
|
711 | =item fork with pthread backend |
|
|
712 | |
|
|
713 | When Coro is compiled using the pthread backend (which isn't recommended |
|
|
714 | but required on many BSDs as their libcs are completely broken), then |
|
|
715 | coroutines will not survive a fork. There is no known workaround except to |
|
|
716 | fix your libc and use a saner backend. |
|
|
717 | |
|
|
718 | =item perl process emulation ("threads") |
664 | |
719 | |
665 | This module is not perl-pseudo-thread-safe. You should only ever use this |
720 | This module is not perl-pseudo-thread-safe. You should only ever use this |
666 | module from the same thread (this requirement might be removed in the |
721 | module from the same thread (this requirement might be removed in the |
667 | future to allow per-thread schedulers, but Coro::State does not yet allow |
722 | future to allow per-thread schedulers, but Coro::State does not yet allow |
668 | this). I recommend disabling thread support and using processes, as this |
723 | this). I recommend disabling thread support and using processes, as having |
669 | is much faster and uses less memory. |
724 | the windows process emulation enabled under unix roughly halves perl |
|
|
725 | performance, even when not used. |
|
|
726 | |
|
|
727 | =item coroutine switching not signal safe |
|
|
728 | |
|
|
729 | You must not switch to another coroutine from within a signal handler |
|
|
730 | (only relevant with %SIG - most event libraries provide safe signals). |
|
|
731 | |
|
|
732 | That means you I<MUST NOT> call any function that might "block" the |
|
|
733 | current coroutine - C<cede>, C<schedule> C<< Coro::Semaphore->down >> or |
|
|
734 | anything that calls those. Everything else, including calling C<ready>, |
|
|
735 | works. |
|
|
736 | |
|
|
737 | =back |
|
|
738 | |
670 | |
739 | |
671 | =head1 SEE ALSO |
740 | =head1 SEE ALSO |
672 | |
741 | |
673 | Event-Loop integration: L<Coro::AnyEvent>, L<Coro::EV>, L<Coro::Event>. |
742 | Event-Loop integration: L<Coro::AnyEvent>, L<Coro::EV>, L<Coro::Event>. |
674 | |
743 | |