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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 1.121 by root, Fri Apr 13 12:56:55 2007 UTC

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 = '3.3'; 55our $VERSION = '3.56';
56 56
57our @EXPORT = qw(async cede schedule terminate current unblock_sub); 57our @EXPORT = qw(async async_pool cede schedule terminate current unblock_sub);
58our %EXPORT_TAGS = ( 58our %EXPORT_TAGS = (
59 prio => [qw(PRIO_MAX PRIO_HIGH PRIO_NORMAL PRIO_LOW PRIO_IDLE PRIO_MIN)], 59 prio => [qw(PRIO_MAX PRIO_HIGH PRIO_NORMAL PRIO_LOW PRIO_IDLE PRIO_MIN)],
60); 60);
61our @EXPORT_OK = (@{$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
185 185
186Create a new asynchronous coroutine and return it's coroutine object 186Create a new asynchronous coroutine and return it's coroutine object
187(usually unused). When the sub returns the new coroutine is automatically 187(usually unused). When the sub returns the new coroutine is automatically
188terminated. 188terminated.
189 189
190Calling C<exit> in a coroutine will not work correctly, so do not do that. 190Calling C<exit> in a coroutine will try to do the same as calling exit
191outside the coroutine, but this is experimental. It is best not to rely on
192exit doing any cleanups or even not crashing.
191 193
192When the coroutine dies, the program will exit, just as in the main 194When the coroutine dies, the program will exit, just as in the main
193program. 195program.
194 196
195 # create a new coroutine that just prints its arguments 197 # create a new coroutine that just prints its arguments
198 } 1,2,3,4; 200 } 1,2,3,4;
199 201
200=cut 202=cut
201 203
202sub async(&@) { 204sub async(&@) {
203 my $pid = new Coro @_; 205 my $coro = new Coro @_;
204 $pid->ready; 206 $coro->ready;
205 $pid 207 $coro
208}
209
210=item async_pool { ... } [@args...]
211
212Similar to C<async>, but uses a coroutine pool, so you should not call
213terminate or join (although you are allowed to), and you get a coroutine
214that might have executed other code already (which can be good or bad :).
215
216Also, the block is executed in an C<eval> context and a warning will be
217issued 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>
219will not work in the expected way, unless you call terminate or cancel,
220which somehow defeats the purpose of pooling.
221
222The priority will be reset to C<0> after each job, otherwise the coroutine
223will be re-used "as-is".
224
225The 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
227required.
228
229If 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 {
231terminate }> once per second or so to slowly replenish the pool.
232
233=cut
234
235our $POOL_SIZE = 8;
236our @pool;
237
238sub pool_handler {
239 while () {
240 eval {
241 my ($cb, @arg) = @{ delete $current->{_invoke} or return };
242 $cb->(@arg);
243 };
244 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 }
253}
254
255sub async_pool(&@) {
256 # this is also inlined into the unlock_scheduler
257 my $coro = (pop @pool or new Coro \&pool_handler);
258
259 $coro->{_invoke} = [@_];
260 $coro->ready;
261
262 $coro
206} 263}
207 264
208=item schedule 265=item schedule
209 266
210Calls the scheduler. Please note that the current coroutine will not be put 267Calls the scheduler. Please note that the current coroutine will not be put
235 292
236"Cede" to other coroutines. This function puts the current coroutine into the 293"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 294ready queue and calls C<schedule>, which has the effect of giving up the
238current "timeslice" to other coroutines of the same or higher priority. 295current "timeslice" to other coroutines of the same or higher priority.
239 296
297Returns true if at least one coroutine switch has happened.
298
299=item Coro::cede_notself
300
301Works like cede, but is not exported by default and will cede to any
302coroutine, regardless of priority, once.
303
304Returns true if at least one coroutine switch has happened.
305
240=item terminate [arg...] 306=item terminate [arg...]
241 307
242Terminates the current coroutine with the given status values (see L<cancel>). 308Terminates the current coroutine with the given status values (see L<cancel>).
243 309
244=cut 310=cut
262Create a new coroutine and return it. When the sub returns the coroutine 328Create a new coroutine and return it. When the sub returns the coroutine
263automatically terminates as if C<terminate> with the returned values were 329automatically terminates as if C<terminate> with the returned values were
264called. To make the coroutine run you must first put it into the ready queue 330called. To make the coroutine run you must first put it into the ready queue
265by calling the ready method. 331by calling the ready method.
266 332
267Calling C<exit> in a coroutine will not work correctly, so do not do that. 333See C<async> for additional discussion.
268 334
269=cut 335=cut
270 336
271sub _run_coro { 337sub _run_coro {
272 terminate &{+shift}; 338 terminate &{+shift};
289Return wether the coroutine is currently the ready queue or not, 355Return wether the coroutine is currently the ready queue or not,
290 356
291=item $coroutine->cancel (arg...) 357=item $coroutine->cancel (arg...)
292 358
293Terminates the given coroutine and makes it return the given arguments as 359Terminates the given coroutine and makes it return the given arguments as
294status (default: the empty list). 360status (default: the empty list). Never returns if the coroutine is the
361current coroutine.
295 362
296=cut 363=cut
297 364
298sub cancel { 365sub cancel {
299 my $self = shift; 366 my $self = shift;
300 $self->{status} = [@_]; 367 $self->{status} = [@_];
368
369 if ($current == $self) {
301 push @destroy, $self; 370 push @destroy, $self;
302 $manager->ready; 371 $manager->ready;
303 &schedule if $current == $self; 372 &schedule while 1;
373 } else {
374 $self->_cancel;
375 }
304} 376}
305 377
306=item $coroutine->join 378=item $coroutine->join
307 379
308Wait until the coroutine terminates and return any values given to the 380Wait until the coroutine terminates and return any values given to the
311 383
312=cut 384=cut
313 385
314sub join { 386sub join {
315 my $self = shift; 387 my $self = shift;
388
316 unless ($self->{status}) { 389 unless ($self->{status}) {
317 push @{$self->{join}}, $current; 390 my $current = $current;
318 &schedule; 391
392 push @{$self->{destroy_cb}}, sub {
393 $current->ready;
394 undef $current;
395 };
396
397 &schedule while $current;
319 } 398 }
399
320 wantarray ? @{$self->{status}} : $self->{status}[0]; 400 wantarray ? @{$self->{status}} : $self->{status}[0];
321} 401}
322 402
323=item $coroutine->on_destroy (\&cb) 403=item $coroutine->on_destroy (\&cb)
324 404
386i.e. that can be swicthed to. The value C<0> means that the only runnable 466i.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, 467coroutine 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 468and C<schedule> would cause a deadlock unless there is an idle handler
389that wakes up some coroutines. 469that wakes up some coroutines.
390 470
471=item my $guard = Coro::guard { ... }
472
473This creates and returns a guard object. Nothing happens until the object
474gets destroyed, in which case the codeblock given as argument will be
475executed. This is useful to free locks or other resources in case of a
476runtime error or when the coroutine gets canceled, as in both cases the
477guard block will be executed. The guard object supports only one method,
478C<< ->cancel >>, which will keep the codeblock from being executed.
479
480Example: set some flag and clear it again when the coroutine gets canceled
481or the function returns:
482
483 sub do_something {
484 my $guard = Coro::guard { $busy = 0 };
485 $busy = 1;
486
487 # do something that requires $busy to be true
488 }
489
490=cut
491
492sub guard(&) {
493 bless \(my $cb = $_[0]), "Coro::guard"
494}
495
496sub Coro::guard::cancel {
497 ${$_[0]} = sub { };
498}
499
500sub Coro::guard::DESTROY {
501 ${$_[0]}->();
502}
503
504
391=item unblock_sub { ... } 505=item unblock_sub { ... }
392 506
393This utility function takes a BLOCK or code reference and "unblocks" it, 507This utility function takes a BLOCK or code reference and "unblocks" it,
394returning the new coderef. This means that the new coderef will return 508returning the new coderef. This means that the new coderef will return
395immediately without blocking, returning nothing, while the original code 509immediately without blocking, returning nothing, while the original code
408In short: simply use C<unblock_sub { ... }> instead of C<sub { ... }> when 522In short: simply use C<unblock_sub { ... }> instead of C<sub { ... }> when
409creating event callbacks that want to block. 523creating event callbacks that want to block.
410 524
411=cut 525=cut
412 526
413our @unblock_pool;
414our @unblock_queue; 527our @unblock_queue;
415our $UNBLOCK_POOL_SIZE = 2;
416 528
417sub unblock_handler_ { 529# we create a special coro because we want to cede,
418 while () { 530# to reduce pressure on the coro pool (because most callbacks
419 my ($cb, @arg) = @{ delete $Coro::current->{arg} }; 531# return immediately and can be reused) and because we cannot cede
420 $cb->(@arg); 532# 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 { 533our $unblock_scheduler = async {
429 while () { 534 while () {
430 while (my $cb = pop @unblock_queue) { 535 while (my $cb = pop @unblock_queue) {
536 # this is an inlined copy of async_pool
431 my $handler = (pop @unblock_pool or new Coro \&unblock_handler_); 537 my $coro = (pop @pool or new Coro \&pool_handler);
432 $handler->{arg} = $cb; 538
539 $coro->{_invoke} = $cb;
433 $handler->ready; 540 $coro->ready;
434 cede; 541 cede; # for short-lived callbacks, this reduces pressure on the coro pool
435 } 542 }
436 543 schedule; # sleep well
437 schedule;
438 } 544 }
439}; 545};
440 546
441sub unblock_sub(&) { 547sub unblock_sub(&) {
442 my $cb = shift; 548 my $cb = shift;
443 549
444 sub { 550 sub {
445 push @unblock_queue, [$cb, @_]; 551 unshift @unblock_queue, [$cb, @_];
446 $unblock_scheduler->ready; 552 $unblock_scheduler->ready;
447 } 553 }
448} 554}
449 555
450=back 556=back

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