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Revision 1.121 by root, Fri Apr 13 12:56:55 2007 UTC vs.
Revision 1.148 by root, Fri Oct 5 20:11:25 2007 UTC

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20 20
21=head1 DESCRIPTION 21=head1 DESCRIPTION
22 22
23This module collection manages coroutines. Coroutines are similar 23This module collection manages coroutines. Coroutines are similar
24to threads but don't run in parallel at the same time even on SMP 24to threads but don't run in parallel at the same time even on SMP
25machines. The specific flavor of coroutine use din this module also 25machines. The specific flavor of coroutine used in this module also
26guarentees you that it will not switch between coroutines unless 26guarantees you that it will not switch between coroutines unless
27necessary, at easily-identified points in your program, so locking and 27necessary, at easily-identified points in your program, so locking and
28parallel access are rarely an issue, making coroutine programming much 28parallel access are rarely an issue, making coroutine programming much
29safer than threads programming. 29safer than threads programming.
30 30
31(Perl, however, does not natively support real threads but instead does a 31(Perl, however, does not natively support real threads but instead does a
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50 50
51our $idle; # idle handler 51our $idle; # idle handler
52our $main; # main coroutine 52our $main; # main coroutine
53our $current; # current coroutine 53our $current; # current coroutine
54 54
55our $VERSION = '3.56'; 55our $VERSION = '4.01';
56 56
57our @EXPORT = qw(async async_pool cede schedule terminate current unblock_sub); 57our @EXPORT = qw(async async_pool cede schedule terminate current unblock_sub);
58our %EXPORT_TAGS = ( 58our %EXPORT_TAGS = (
59 prio => [qw(PRIO_MAX PRIO_HIGH PRIO_NORMAL PRIO_LOW PRIO_IDLE PRIO_MIN)], 59 prio => [qw(PRIO_MAX PRIO_HIGH PRIO_NORMAL PRIO_LOW PRIO_IDLE PRIO_MIN)],
60); 60);
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108 108
109The current coroutine (the last coroutine switched to). The initial value 109The current coroutine (the last coroutine switched to). The initial value
110is C<$main> (of course). 110is C<$main> (of course).
111 111
112This variable is B<strictly> I<read-only>. It is provided for performance 112This variable is B<strictly> I<read-only>. It is provided for performance
113reasons. If performance is not essentiel you are encouraged to use the 113reasons. If performance is not essential you are encouraged to use the
114C<Coro::current> function instead. 114C<Coro::current> function instead.
115 115
116=cut 116=cut
117 117
118$main->{desc} = "[main::]";
119
118# maybe some other module used Coro::Specific before... 120# maybe some other module used Coro::Specific before...
119$main->{specific} = $current->{specific} 121$main->{_specific} = $current->{_specific}
120 if $current; 122 if $current;
121 123
122_set_current $main; 124_set_current $main;
123 125
124sub current() { $current } 126sub current() { $current }
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149 # free coroutine data and mark as destructed 151 # free coroutine data and mark as destructed
150 $self->_destroy 152 $self->_destroy
151 or return; 153 or return;
152 154
153 # call all destruction callbacks 155 # call all destruction callbacks
154 $_->(@{$self->{status}}) 156 $_->(@{$self->{_status}})
155 for @{(delete $self->{destroy_cb}) || []}; 157 for @{(delete $self->{_on_destroy}) || []};
156} 158}
157 159
158# this coroutine is necessary because a coroutine 160# this coroutine is necessary because a coroutine
159# cannot destroy itself. 161# cannot destroy itself.
160my @destroy; 162my @destroy;
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166 while @destroy; 168 while @destroy;
167 169
168 &schedule; 170 &schedule;
169 } 171 }
170}; 172};
171 173$manager->desc ("[coro manager]");
172$manager->prio (PRIO_MAX); 174$manager->prio (PRIO_MAX);
173 175
174# static methods. not really. 176# static methods. not really.
175 177
176=back 178=back
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185 187
186Create a new asynchronous coroutine and return it's coroutine object 188Create a new asynchronous coroutine and return it's coroutine object
187(usually unused). When the sub returns the new coroutine is automatically 189(usually unused). When the sub returns the new coroutine is automatically
188terminated. 190terminated.
189 191
192See the C<Coro::State::new> constructor for info about the coroutine
193environment.
194
190Calling C<exit> in a coroutine will try to do the same as calling exit 195Calling C<exit> in a coroutine will do the same as calling exit outside
191outside the coroutine, but this is experimental. It is best not to rely on 196the coroutine. Likewise, when the coroutine dies, the program will exit,
192exit doing any cleanups or even not crashing. 197just as it would in the main program.
193
194When the coroutine dies, the program will exit, just as in the main
195program.
196 198
197 # create a new coroutine that just prints its arguments 199 # create a new coroutine that just prints its arguments
198 async { 200 async {
199 print "@_\n"; 201 print "@_\n";
200 } 1,2,3,4; 202 } 1,2,3,4;
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217issued in case of an exception instead of terminating the program, as 219issued in case of an exception instead of terminating the program, as
218C<async> does. As the coroutine is being reused, stuff like C<on_destroy> 220C<async> does. As the coroutine is being reused, stuff like C<on_destroy>
219will not work in the expected way, unless you call terminate or cancel, 221will not work in the expected way, unless you call terminate or cancel,
220which somehow defeats the purpose of pooling. 222which somehow defeats the purpose of pooling.
221 223
222The priority will be reset to C<0> after each job, otherwise the coroutine 224The priority will be reset to C<0> after each job, tracing will be
223will be re-used "as-is". 225disabled, the description will be reset and the default output filehandle
226gets restored, so you can change alkl these. Otherwise the coroutine will
227be re-used "as-is": most notably if you change other per-coroutine global
228stuff such as C<$/> you need to revert that change, which is most simply
229done by using local as in C< local $/ >.
224 230
225The pool size is limited to 8 idle coroutines (this can be adjusted by 231The pool size is limited to 8 idle coroutines (this can be adjusted by
226changing $Coro::POOL_SIZE), and there can be as many non-idle coros as 232changing $Coro::POOL_SIZE), and there can be as many non-idle coros as
227required. 233required.
228 234
229If you are concerned about pooled coroutines growing a lot because a 235If you are concerned about pooled coroutines growing a lot because a
230single C<async_pool> used a lot of stackspace you can e.g. C<async_pool { 236single C<async_pool> used a lot of stackspace you can e.g. C<async_pool
231terminate }> once per second or so to slowly replenish the pool. 237{ terminate }> once per second or so to slowly replenish the pool. In
238addition to that, when the stacks used by a handler grows larger than 16kb
239(adjustable with $Coro::POOL_RSS) it will also exit.
232 240
233=cut 241=cut
234 242
235our $POOL_SIZE = 8; 243our $POOL_SIZE = 8;
244our $POOL_RSS = 16 * 1024;
236our @pool; 245our @async_pool;
237 246
238sub pool_handler { 247sub pool_handler {
248 my $cb;
249
239 while () { 250 while () {
240 eval { 251 eval {
241 my ($cb, @arg) = @{ delete $current->{_invoke} or return }; 252 while () {
242 $cb->(@arg); 253 _pool_1 $cb;
254 &$cb;
255 _pool_2 $cb;
256 &schedule;
257 }
243 }; 258 };
259
260 last if $@ eq "\3terminate\2\n";
244 warn $@ if $@; 261 warn $@ if $@;
245
246 last if @pool >= $POOL_SIZE;
247 push @pool, $current;
248
249 $current->save (Coro::State::SAVE_DEF);
250 $current->prio (0);
251 schedule;
252 } 262 }
253} 263}
254 264
255sub async_pool(&@) { 265sub async_pool(&@) {
256 # this is also inlined into the unlock_scheduler 266 # this is also inlined into the unlock_scheduler
257 my $coro = (pop @pool or new Coro \&pool_handler); 267 my $coro = (pop @async_pool) || new Coro \&pool_handler;
258 268
259 $coro->{_invoke} = [@_]; 269 $coro->{_invoke} = [@_];
260 $coro->ready; 270 $coro->ready;
261 271
262 $coro 272 $coro
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280 # wake up sleeping coroutine 290 # wake up sleeping coroutine
281 $current->ready; 291 $current->ready;
282 undef $current; 292 undef $current;
283 }; 293 };
284 294
285 # call schedule until event occured. 295 # call schedule until event occurred.
286 # in case we are woken up for other reasons 296 # in case we are woken up for other reasons
287 # (current still defined), loop. 297 # (current still defined), loop.
288 Coro::schedule while $current; 298 Coro::schedule while $current;
289 } 299 }
290 300
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305 315
306=item terminate [arg...] 316=item terminate [arg...]
307 317
308Terminates the current coroutine with the given status values (see L<cancel>). 318Terminates the current coroutine with the given status values (see L<cancel>).
309 319
320=item killall
321
322Kills/terminates/cancels all coroutines except the currently running
323one. This is useful after a fork, either in the child or the parent, as
324usually only one of them should inherit the running coroutines.
325
310=cut 326=cut
311 327
312sub terminate { 328sub terminate {
313 $current->cancel (@_); 329 $current->cancel (@_);
330}
331
332sub killall {
333 for (Coro::State::list) {
334 $_->cancel
335 if $_ != $current && UNIVERSAL::isa $_, "Coro";
336 }
314} 337}
315 338
316=back 339=back
317 340
318# dynamic methods 341# dynamic methods
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328Create a new coroutine and return it. When the sub returns the coroutine 351Create a new coroutine and return it. When the sub returns the coroutine
329automatically terminates as if C<terminate> with the returned values were 352automatically terminates as if C<terminate> with the returned values were
330called. To make the coroutine run you must first put it into the ready queue 353called. To make the coroutine run you must first put it into the ready queue
331by calling the ready method. 354by calling the ready method.
332 355
333See C<async> for additional discussion. 356See C<async> and C<Coro::State::new> for additional info about the
357coroutine environment.
334 358
335=cut 359=cut
336 360
337sub _run_coro { 361sub _run_coro {
338 terminate &{+shift}; 362 terminate &{+shift};
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362 386
363=cut 387=cut
364 388
365sub cancel { 389sub cancel {
366 my $self = shift; 390 my $self = shift;
367 $self->{status} = [@_]; 391 $self->{_status} = [@_];
368 392
369 if ($current == $self) { 393 if ($current == $self) {
370 push @destroy, $self; 394 push @destroy, $self;
371 $manager->ready; 395 $manager->ready;
372 &schedule while 1; 396 &schedule while 1;
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376} 400}
377 401
378=item $coroutine->join 402=item $coroutine->join
379 403
380Wait until the coroutine terminates and return any values given to the 404Wait until the coroutine terminates and return any values given to the
381C<terminate> or C<cancel> functions. C<join> can be called multiple times 405C<terminate> or C<cancel> functions. C<join> can be called concurrently
382from multiple coroutine. 406from multiple coroutines.
383 407
384=cut 408=cut
385 409
386sub join { 410sub join {
387 my $self = shift; 411 my $self = shift;
388 412
389 unless ($self->{status}) { 413 unless ($self->{_status}) {
390 my $current = $current; 414 my $current = $current;
391 415
392 push @{$self->{destroy_cb}}, sub { 416 push @{$self->{_on_destroy}}, sub {
393 $current->ready; 417 $current->ready;
394 undef $current; 418 undef $current;
395 }; 419 };
396 420
397 &schedule while $current; 421 &schedule while $current;
398 } 422 }
399 423
400 wantarray ? @{$self->{status}} : $self->{status}[0]; 424 wantarray ? @{$self->{_status}} : $self->{_status}[0];
401} 425}
402 426
403=item $coroutine->on_destroy (\&cb) 427=item $coroutine->on_destroy (\&cb)
404 428
405Registers a callback that is called when this coroutine gets destroyed, 429Registers a callback that is called when this coroutine gets destroyed,
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409=cut 433=cut
410 434
411sub on_destroy { 435sub on_destroy {
412 my ($self, $cb) = @_; 436 my ($self, $cb) = @_;
413 437
414 push @{ $self->{destroy_cb} }, $cb; 438 push @{ $self->{_on_destroy} }, $cb;
415} 439}
416 440
417=item $oldprio = $coroutine->prio ($newprio) 441=item $oldprio = $coroutine->prio ($newprio)
418 442
419Sets (or gets, if the argument is missing) the priority of the 443Sets (or gets, if the argument is missing) the priority of the
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444=item $olddesc = $coroutine->desc ($newdesc) 468=item $olddesc = $coroutine->desc ($newdesc)
445 469
446Sets (or gets in case the argument is missing) the description for this 470Sets (or gets in case the argument is missing) the description for this
447coroutine. This is just a free-form string you can associate with a coroutine. 471coroutine. This is just a free-form string you can associate with a coroutine.
448 472
473This method simply sets the C<< $coroutine->{desc} >> member to the given string. You
474can modify this member directly if you wish.
475
449=cut 476=cut
450 477
451sub desc { 478sub desc {
452 my $old = $_[0]{desc}; 479 my $old = $_[0]{desc};
453 $_[0]{desc} = $_[1] if @_ > 1; 480 $_[0]{desc} = $_[1] if @_ > 1;
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461=over 4 488=over 4
462 489
463=item Coro::nready 490=item Coro::nready
464 491
465Returns the number of coroutines that are currently in the ready state, 492Returns the number of coroutines that are currently in the ready state,
466i.e. that can be swicthed to. The value C<0> means that the only runnable 493i.e. that can be switched to. The value C<0> means that the only runnable
467coroutine is the currently running one, so C<cede> would have no effect, 494coroutine is the currently running one, so C<cede> would have no effect,
468and C<schedule> would cause a deadlock unless there is an idle handler 495and C<schedule> would cause a deadlock unless there is an idle handler
469that wakes up some coroutines. 496that wakes up some coroutines.
470 497
471=item my $guard = Coro::guard { ... } 498=item my $guard = Coro::guard { ... }
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507This utility function takes a BLOCK or code reference and "unblocks" it, 534This utility function takes a BLOCK or code reference and "unblocks" it,
508returning the new coderef. This means that the new coderef will return 535returning the new coderef. This means that the new coderef will return
509immediately without blocking, returning nothing, while the original code 536immediately without blocking, returning nothing, while the original code
510ref will be called (with parameters) from within its own coroutine. 537ref will be called (with parameters) from within its own coroutine.
511 538
512The reason this fucntion exists is that many event libraries (such as the 539The reason this function exists is that many event libraries (such as the
513venerable L<Event|Event> module) are not coroutine-safe (a weaker form 540venerable L<Event|Event> module) are not coroutine-safe (a weaker form
514of thread-safety). This means you must not block within event callbacks, 541of thread-safety). This means you must not block within event callbacks,
515otherwise you might suffer from crashes or worse. 542otherwise you might suffer from crashes or worse.
516 543
517This function allows your callbacks to block by executing them in another 544This function allows your callbacks to block by executing them in another
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528 555
529# we create a special coro because we want to cede, 556# we create a special coro because we want to cede,
530# to reduce pressure on the coro pool (because most callbacks 557# to reduce pressure on the coro pool (because most callbacks
531# return immediately and can be reused) and because we cannot cede 558# return immediately and can be reused) and because we cannot cede
532# inside an event callback. 559# inside an event callback.
533our $unblock_scheduler = async { 560our $unblock_scheduler = new Coro sub {
534 while () { 561 while () {
535 while (my $cb = pop @unblock_queue) { 562 while (my $cb = pop @unblock_queue) {
536 # this is an inlined copy of async_pool 563 # this is an inlined copy of async_pool
537 my $coro = (pop @pool or new Coro \&pool_handler); 564 my $coro = (pop @async_pool) || new Coro \&pool_handler;
538 565
539 $coro->{_invoke} = $cb; 566 $coro->{_invoke} = $cb;
540 $coro->ready; 567 $coro->ready;
541 cede; # for short-lived callbacks, this reduces pressure on the coro pool 568 cede; # for short-lived callbacks, this reduces pressure on the coro pool
542 } 569 }
543 schedule; # sleep well 570 schedule; # sleep well
544 } 571 }
545}; 572};
573$unblock_scheduler->desc ("[unblock_sub scheduler]");
546 574
547sub unblock_sub(&) { 575sub unblock_sub(&) {
548 my $cb = shift; 576 my $cb = shift;
549 577
550 sub { 578 sub {
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563 591
564 - you must make very sure that no coro is still active on global 592 - you must make very sure that no coro is still active on global
565 destruction. very bad things might happen otherwise (usually segfaults). 593 destruction. very bad things might happen otherwise (usually segfaults).
566 594
567 - this module is not thread-safe. You should only ever use this module 595 - this module is not thread-safe. You should only ever use this module
568 from the same thread (this requirement might be losened in the future 596 from the same thread (this requirement might be loosened in the future
569 to allow per-thread schedulers, but Coro::State does not yet allow 597 to allow per-thread schedulers, but Coro::State does not yet allow
570 this). 598 this).
571 599
572=head1 SEE ALSO 600=head1 SEE ALSO
573 601
574Support/Utility: L<Coro::Cont>, L<Coro::Specific>, L<Coro::State>, L<Coro::Util>. 602Support/Utility: L<Coro::Specific>, L<Coro::State>, L<Coro::Util>.
575 603
576Locking/IPC: L<Coro::Signal>, L<Coro::Channel>, L<Coro::Semaphore>, L<Coro::SemaphoreSet>, L<Coro::RWLock>. 604Locking/IPC: L<Coro::Signal>, L<Coro::Channel>, L<Coro::Semaphore>, L<Coro::SemaphoreSet>, L<Coro::RWLock>.
577 605
578Event/IO: L<Coro::Timer>, L<Coro::Event>, L<Coro::Handle>, L<Coro::Socket>, L<Coro::Select>. 606Event/IO: L<Coro::Timer>, L<Coro::Event>, L<Coro::Handle>, L<Coro::Socket>, L<Coro::Select>.
579 607

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