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Comparing cvsroot/Coro/Coro.pm (file contents):
Revision 1.101 by root, Fri Dec 29 08:36:34 2006 UTC vs.
Revision 1.105 by root, Fri Jan 5 16:55:01 2007 UTC

52our $main; # main coroutine 52our $main; # main coroutine
53our $current; # current coroutine 53our $current; # current coroutine
54 54
55our $VERSION = '3.3'; 55our $VERSION = '3.3';
56 56
57our @EXPORT = qw(async cede schedule terminate current unblock_sub); 57our @EXPORT = qw(async async_pool cede schedule terminate current unblock_sub);
58our %EXPORT_TAGS = ( 58our %EXPORT_TAGS = (
59 prio => [qw(PRIO_MAX PRIO_HIGH PRIO_NORMAL PRIO_LOW PRIO_IDLE PRIO_MIN)], 59 prio => [qw(PRIO_MAX PRIO_HIGH PRIO_NORMAL PRIO_LOW PRIO_IDLE PRIO_MIN)],
60); 60);
61our @EXPORT_OK = (@{$EXPORT_TAGS{prio}}, qw(nready)); 61our @EXPORT_OK = (@{$EXPORT_TAGS{prio}}, qw(nready));
62 62
141$idle = sub { 141$idle = sub {
142 require Carp; 142 require Carp;
143 Carp::croak ("FATAL: deadlock detected"); 143 Carp::croak ("FATAL: deadlock detected");
144}; 144};
145 145
146sub _cancel {
147 my ($self) = @_;
148
149 # free coroutine data and mark as destructed
150 $self->_destroy
151 or return;
152
153 # call all destruction callbacks
154 $_->(@{$self->{status}})
155 for @{(delete $self->{destroy_cb}) || []};
156}
157
146# this coroutine is necessary because a coroutine 158# this coroutine is necessary because a coroutine
147# cannot destroy itself. 159# cannot destroy itself.
148my @destroy; 160my @destroy;
161my $manager;
162
149my $manager; $manager = new Coro sub { 163$manager = new Coro sub {
150 while () { 164 while () {
151 # by overwriting the state object with the manager we destroy it 165 (shift @destroy)->_cancel
152 # while still being able to schedule this coroutine (in case it has
153 # been readied multiple times. this is harmless since the manager
154 # can be called as many times as neccessary and will always
155 # remove itself from the runqueue
156 while (@destroy) { 166 while @destroy;
157 my $coro = pop @destroy;
158 167
159 $coro->{status} ||= [];
160
161 $_->ready for @{(delete $coro->{join} ) || []};
162 $_->(@{$coro->{status}}) for @{(delete $coro->{destroy_cb}) || []};
163
164 # the next line destroys the coro state, but keeps the
165 # coroutine itself intact (we basically make it a zombie
166 # coroutine that always runs the manager thread, so it's possible
167 # to transfer() to this coroutine).
168 $coro->_clone_state_from ($manager);
169 }
170 &schedule; 168 &schedule;
171 } 169 }
172}; 170};
171
172$manager->prio (PRIO_MAX);
173 173
174# static methods. not really. 174# static methods. not really.
175 175
176=back 176=back
177 177
198 } 1,2,3,4; 198 } 1,2,3,4;
199 199
200=cut 200=cut
201 201
202sub async(&@) { 202sub async(&@) {
203 my $pid = new Coro @_; 203 my $coro = new Coro @_;
204 $pid->ready; 204 $coro->ready;
205 $pid 205 $coro
206}
207
208=item async_pool { ... } [@args...]
209
210Similar to C<async>, but uses a coroutine pool, so you should not call
211terminate or join (although you are allowed to), and you get a coroutine
212that might have executed other code already (which can be good or bad :).
213
214Also, the block is executed in an C<eval> context and a warning will be
215issued in case of an exception instead of terminating the program, as C<async> does.
216
217The priority will be reset to C<0> after each job, otherwise the coroutine
218will be re-used "as-is".
219
220The pool size is limited to 8 idle coroutines (this can be adjusted by
221changing $Coro::POOL_SIZE), and there can be as many non-idle coros as
222required.
223
224If you are concerned about pooled coroutines growing a lot because a
225single C<async_pool> used a lot of stackspace you can e.g. C<async_pool {
226terminate }> once per second or so to slowly replenish the pool.
227
228=cut
229
230our $POOL_SIZE = 8;
231our @pool;
232
233sub pool_handler {
234 while () {
235 my ($cb, @arg) = @{ delete $current->{_invoke} };
236
237 eval {
238 $cb->(@arg);
239 };
240 warn $@ if $@;
241
242 last if @pool >= $POOL_SIZE;
243 push @pool, $current;
244
245 $current->prio (0);
246 schedule;
247 }
248}
249
250sub async_pool(&@) {
251 # this is also inlined into the unlock_scheduler
252 my $coro = (pop @pool or new Coro \&pool_handler);
253
254 $coro->{_invoke} = [@_];
255 $coro->ready;
256
257 $coro
206} 258}
207 259
208=item schedule 260=item schedule
209 261
210Calls the scheduler. Please note that the current coroutine will not be put 262Calls the scheduler. Please note that the current coroutine will not be put
235 287
236"Cede" to other coroutines. This function puts the current coroutine into the 288"Cede" to other coroutines. This function puts the current coroutine into the
237ready queue and calls C<schedule>, which has the effect of giving up the 289ready queue and calls C<schedule>, which has the effect of giving up the
238current "timeslice" to other coroutines of the same or higher priority. 290current "timeslice" to other coroutines of the same or higher priority.
239 291
292=item Coro::cede_notself
293
294Works like cede, but is not exported by default and will cede to any
295coroutine, regardless of priority, once.
296
240=item terminate [arg...] 297=item terminate [arg...]
241 298
242Terminates the current coroutine with the given status values (see L<cancel>). 299Terminates the current coroutine with the given status values (see L<cancel>).
243 300
244=cut 301=cut
289Return wether the coroutine is currently the ready queue or not, 346Return wether the coroutine is currently the ready queue or not,
290 347
291=item $coroutine->cancel (arg...) 348=item $coroutine->cancel (arg...)
292 349
293Terminates the given coroutine and makes it return the given arguments as 350Terminates the given coroutine and makes it return the given arguments as
294status (default: the empty list). 351status (default: the empty list). Never returns if the coroutine is the
352current coroutine.
295 353
296=cut 354=cut
297 355
298sub cancel { 356sub cancel {
299 my $self = shift; 357 my $self = shift;
300 $self->{status} = [@_]; 358 $self->{status} = [@_];
359
360 if ($current == $self) {
301 push @destroy, $self; 361 push @destroy, $self;
302 $manager->ready; 362 $manager->ready;
303 &schedule if $current == $self; 363 &schedule while 1;
364 } else {
365 $self->_cancel;
366 }
304} 367}
305 368
306=item $coroutine->join 369=item $coroutine->join
307 370
308Wait until the coroutine terminates and return any values given to the 371Wait until the coroutine terminates and return any values given to the
311 374
312=cut 375=cut
313 376
314sub join { 377sub join {
315 my $self = shift; 378 my $self = shift;
379
316 unless ($self->{status}) { 380 unless ($self->{status}) {
317 push @{$self->{join}}, $current; 381 my $current = $current;
318 &schedule; 382
383 push @{$self->{destroy_cb}}, sub {
384 $current->ready;
385 undef $current;
386 };
387
388 &schedule while $current;
319 } 389 }
390
320 wantarray ? @{$self->{status}} : $self->{status}[0]; 391 wantarray ? @{$self->{status}} : $self->{status}[0];
321} 392}
322 393
323=item $coroutine->on_destroy (\&cb) 394=item $coroutine->on_destroy (\&cb)
324 395
386i.e. that can be swicthed to. The value C<0> means that the only runnable 457i.e. that can be swicthed to. The value C<0> means that the only runnable
387coroutine is the currently running one, so C<cede> would have no effect, 458coroutine is the currently running one, so C<cede> would have no effect,
388and C<schedule> would cause a deadlock unless there is an idle handler 459and C<schedule> would cause a deadlock unless there is an idle handler
389that wakes up some coroutines. 460that wakes up some coroutines.
390 461
462=item my $guard = Coro::guard { ... }
463
464This creates and returns a guard object. Nothing happens until the objetc
465gets destroyed, in which case the codeblock given as argument will be
466executed. This is useful to free locks or other resources in case of a
467runtime error or when the coroutine gets canceled, as in both cases the
468guard block will be executed. The guard object supports only one method,
469C<< ->cancel >>, which will keep the codeblock from being executed.
470
471Example: set some flag and clear it again when the coroutine gets canceled
472or the function returns:
473
474 sub do_something {
475 my $guard = Coro::guard { $busy = 0 };
476 $busy = 1;
477
478 # do something that requires $busy to be true
479 }
480
481=cut
482
483sub guard(&) {
484 bless \(my $cb = $_[0]), "Coro::guard"
485}
486
487sub Coro::guard::cancel {
488 ${$_[0]} = sub { };
489}
490
491sub Coro::guard::DESTROY {
492 ${$_[0]}->();
493}
494
495
391=item unblock_sub { ... } 496=item unblock_sub { ... }
392 497
393This utility function takes a BLOCK or code reference and "unblocks" it, 498This utility function takes a BLOCK or code reference and "unblocks" it,
394returning the new coderef. This means that the new coderef will return 499returning the new coderef. This means that the new coderef will return
395immediately without blocking, returning nothing, while the original code 500immediately without blocking, returning nothing, while the original code
408In short: simply use C<unblock_sub { ... }> instead of C<sub { ... }> when 513In short: simply use C<unblock_sub { ... }> instead of C<sub { ... }> when
409creating event callbacks that want to block. 514creating event callbacks that want to block.
410 515
411=cut 516=cut
412 517
413our @unblock_pool;
414our @unblock_queue; 518our @unblock_queue;
415our $UNBLOCK_POOL_SIZE = 2;
416 519
417sub unblock_handler_ { 520# we create a special coro because we want to cede,
418 while () { 521# to reduce pressure on the coro pool (because most callbacks
419 my ($cb, @arg) = @{ delete $Coro::current->{arg} }; 522# return immediately and can be reused) and because we cannot cede
420 $cb->(@arg); 523# inside an event callback.
421
422 last if @unblock_pool >= $UNBLOCK_POOL_SIZE;
423 push @unblock_pool, $Coro::current;
424 schedule;
425 }
426}
427
428our $unblock_scheduler = async { 524our $unblock_scheduler = async {
429 while () { 525 while () {
430 while (my $cb = pop @unblock_queue) { 526 while (my $cb = pop @unblock_queue) {
527 # this is an inlined copy of async_pool
431 my $handler = (pop @unblock_pool or new Coro \&unblock_handler_); 528 my $coro = (pop @pool or new Coro \&pool_handler);
432 $handler->{arg} = $cb; 529
530 $coro->{_invoke} = $cb;
433 $handler->ready; 531 $coro->ready;
434 cede; 532 cede; # for short-lived callbacks, this reduces pressure on the coro pool
435 } 533 }
436 534 schedule; # sleep well
437 schedule;
438 } 535 }
439}; 536};
440 537
441sub unblock_sub(&) { 538sub unblock_sub(&) {
442 my $cb = shift; 539 my $cb = shift;
443 540
444 sub { 541 sub {
445 push @unblock_queue, [$cb, @_]; 542 unshift @unblock_queue, [$cb, @_];
446 $unblock_scheduler->ready; 543 $unblock_scheduler->ready;
447 } 544 }
448} 545}
449 546
450=back 547=back

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