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Revision 1.191 by root, Sat May 31 12:10:55 2008 UTC vs.
Revision 1.223 by root, Tue Nov 18 10:44:07 2008 UTC

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
58package Coro; 59package Coro;
59 60
60use strict; 61use strict qw(vars subs);
61no warnings "uninitialized"; 62no warnings "uninitialized";
62 63
63use Coro::State; 64use Coro::State;
64 65
65use base qw(Coro::State Exporter); 66use base qw(Coro::State Exporter);
66 67
67our $idle; # idle handler 68our $idle; # idle handler
68our $main; # main coroutine 69our $main; # main coroutine
69our $current; # current coroutine 70our $current; # current coroutine
70 71
71our $VERSION = 4.742; 72our $VERSION = 5.0;
72 73
73our @EXPORT = qw(async async_pool cede schedule terminate current unblock_sub); 74our @EXPORT = qw(async async_pool cede schedule terminate current unblock_sub);
74our %EXPORT_TAGS = ( 75our %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 $Coro::main
82 83
83This variable stores the coroutine object that represents the main 84This variable stores the coroutine object that represents the main
84program. While you cna C<ready> it and do most other things you can do to 85program. While you cna C<ready> it and do most other things you can do to
85coroutines, it is mainly useful to compare again C<$Coro::current>, to see 86coroutines, it is mainly useful to compare again C<$Coro::current>, to see
86wether you are running in the main program or not. 87whether you are running in the main program or not.
87 88
88=cut 89=cut
89 90
90$main = new Coro; 91# $main is now being initialised by Coro::State
91 92
92=item $Coro::current 93=item $Coro::current
93 94
94The coroutine object representing the current coroutine (the last 95The coroutine object representing the current coroutine (the last
95coroutine that the Coro scheduler switched to). The initial value is 96coroutine that the Coro scheduler switched to). The initial value is
96C<$main> (of course). 97C<$Coro::main> (of course).
97 98
98This variable is B<strictly> I<read-only>. You can take copies of the 99This variable is B<strictly> I<read-only>. You can take copies of the
99value stored in it and use it as any other coroutine object, but you must 100value stored in it and use it as any other coroutine object, but you must
100not otherwise modify the variable itself. 101not otherwise modify the variable itself.
101 102
102=cut 103=cut
103
104$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
112sub current() { $current } # [DEPRECATED] 105sub current() { $current } # [DEPRECATED]
113 106
114=item $Coro::idle 107=item $Coro::idle
115 108
151 $self->_destroy 144 $self->_destroy
152 or return; 145 or return;
153 146
154 # call all destruction callbacks 147 # call all destruction callbacks
155 $_->(@{$self->{_status}}) 148 $_->(@{$self->{_status}})
156 for @{(delete $self->{_on_destroy}) || []}; 149 for @{ delete $self->{_on_destroy} || [] };
157} 150}
158 151
159# this coroutine is necessary because a coroutine 152# this coroutine is necessary because a coroutine
160# cannot destroy itself. 153# cannot destroy itself.
161my @destroy; 154my @destroy;
167 while @destroy; 160 while @destroy;
168 161
169 &schedule; 162 &schedule;
170 } 163 }
171}; 164};
172$manager->desc ("[coro manager]"); 165$manager->{desc} = "[coro manager]";
173$manager->prio (PRIO_MAX); 166$manager->prio (PRIO_MAX);
174 167
175=back 168=back
176 169
177=head2 SIMPLE COROUTINE CREATION 170=head2 SIMPLE COROUTINE CREATION
220terminate or join on it (although you are allowed to), and you get a 213terminate or join on it (although you are allowed to), and you get a
221coroutine that might have executed other code already (which can be good 214coroutine that might have executed other code already (which can be good
222or bad :). 215or bad :).
223 216
224On the plus side, this function is faster than creating (and destroying) 217On the plus side, this function is faster than creating (and destroying)
225a completely new coroutine, so if you need a lot of generic coroutines in 218a completly new coroutine, so if you need a lot of generic coroutines in
226quick successsion, use C<async_pool>, not C<async>. 219quick successsion, use C<async_pool>, not C<async>.
227 220
228The code block is executed in an C<eval> context and a warning will be 221The code block is executed in an C<eval> context and a warning will be
229issued in case of an exception instead of terminating the program, as 222issued in case of an exception instead of terminating the program, as
230C<async> does. As the coroutine is being reused, stuff like C<on_destroy> 223C<async> does. As the coroutine is being reused, stuff like C<on_destroy>
234 227
235The priority will be reset to C<0> after each run, tracing will be 228The priority will be reset to C<0> after each run, tracing will be
236disabled, the description will be reset and the default output filehandle 229disabled, the description will be reset and the default output filehandle
237gets restored, so you can change all these. Otherwise the coroutine will 230gets restored, so you can change all these. Otherwise the coroutine will
238be re-used "as-is": most notably if you change other per-coroutine global 231be re-used "as-is": most notably if you change other per-coroutine global
239stuff such as C<$/> you I<must needs> to revert that change, which is most 232stuff such as C<$/> you I<must needs> revert that change, which is most
240simply done by using local as in: C< local $/ >. 233simply done by using local as in: C<< local $/ >>.
241 234
242The pool size is limited to C<8> idle coroutines (this can be adjusted by 235The idle pool size is limited to C<8> idle coroutines (this can be
243changing $Coro::POOL_SIZE), and there can be as many non-idle coros as 236adjusted by changing $Coro::POOL_SIZE), but there can be as many non-idle
244required. 237coros as required.
245 238
246If you are concerned about pooled coroutines growing a lot because a 239If you are concerned about pooled coroutines growing a lot because a
247single C<async_pool> used a lot of stackspace you can e.g. C<async_pool 240single 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 241{ terminate }> once per second or so to slowly replenish the pool. In
249addition to that, when the stacks used by a handler grows larger than 16kb 242addition to that, when the stacks used by a handler grows larger than 16kb
266 _pool_2 $cb; 259 _pool_2 $cb;
267 &schedule; 260 &schedule;
268 } 261 }
269 }; 262 };
270 263
264 if ($@) {
271 last if $@ eq "\3async_pool terminate\2\n"; 265 last if $@ eq "\3async_pool terminate\2\n";
272 warn $@ if $@; 266 warn $@;
267 }
273 } 268 }
274} 269}
275 270
276sub async_pool(&@) { 271sub async_pool(&@) {
277 # this is also inlined into the unlock_scheduler 272 # this is also inlined into the unblock_scheduler
278 my $coro = (pop @async_pool) || new Coro \&pool_handler; 273 my $coro = (pop @async_pool) || new Coro \&pool_handler;
279 274
280 $coro->{_invoke} = [@_]; 275 $coro->{_invoke} = [@_];
281 $coro->ready; 276 $coro->ready;
282 277
307This makes C<schedule> I<the> generic method to use to block the current 302This makes C<schedule> I<the> generic method to use to block the current
308coroutine and wait for events: first you remember the current coroutine in 303coroutine and wait for events: first you remember the current coroutine in
309a variable, then arrange for some callback of yours to call C<< ->ready 304a variable, then arrange for some callback of yours to call C<< ->ready
310>> on that once some event happens, and last you call C<schedule> to put 305>> on that once some event happens, and last you call C<schedule> to put
311yourself to sleep. Note that a lot of things can wake your coroutine up, 306yourself to sleep. Note that a lot of things can wake your coroutine up,
312so you need to check wether the event indeed happened, e.g. by storing the 307so you need to check whether the event indeed happened, e.g. by storing the
313status in a variable. 308status in a variable.
314 309
315The canonical way to wait on external events is this: 310The canonical way to wait on external events is this:
316 311
317 { 312 {
356Kills/terminates/cancels all coroutines except the currently running 351Kills/terminates/cancels all coroutines except the currently running
357one. This is useful after a fork, either in the child or the parent, as 352one. This is useful after a fork, either in the child or the parent, as
358usually only one of them should inherit the running coroutines. 353usually only one of them should inherit the running coroutines.
359 354
360Note that while this will try to free some of the main programs resources, 355Note that while this will try to free some of the main programs resources,
361you cnanot free all of them, so if a coroutine that is not the main 356you cannot free all of them, so if a coroutine that is not the main
362program calls this function, there will be some one-time resource leak. 357program calls this function, there will be some one-time resource leak.
363 358
364=cut 359=cut
365 360
366sub terminate { 361sub terminate {
415once all the coroutines of higher priority and all coroutines of the same 410once all the coroutines of higher priority and all coroutines of the same
416priority that were put into the ready queue earlier have been resumed. 411priority that were put into the ready queue earlier have been resumed.
417 412
418=item $is_ready = $coroutine->is_ready 413=item $is_ready = $coroutine->is_ready
419 414
420Return wether the coroutine is currently the ready queue or not, 415Return whether the coroutine is currently the ready queue or not,
421 416
422=item $coroutine->cancel (arg...) 417=item $coroutine->cancel (arg...)
423 418
424Terminates the given coroutine and makes it return the given arguments as 419Terminates the given coroutine and makes it return the given arguments as
425status (default: the empty list). Never returns if the coroutine is the 420status (default: the empty list). Never returns if the coroutine is the
438 } else { 433 } else {
439 $self->_cancel; 434 $self->_cancel;
440 } 435 }
441} 436}
442 437
438=item $coroutine->throw ([$scalar])
439
440If C<$throw> is specified and defined, it will be thrown as an exception
441inside the coroutine at the next convenient point in time. Otherwise
442clears the exception object.
443
444Coro will check for the exception each time a schedule-like-function
445returns, i.e. after each C<schedule>, C<cede>, C<< Coro::Semaphore->down
446>>, C<< Coro::Handle->readable >> and so on. Most of these functions
447detect this case and return early in case an exception is pending.
448
449The exception object will be thrown "as is" with the specified scalar in
450C<$@>, i.e. if it is a string, no line number or newline will be appended
451(unlike with C<die>).
452
453This can be used as a softer means than C<cancel> to ask a coroutine to
454end itself, although there is no guarantee that the exception will lead to
455termination, and if the exception isn't caught it might well end the whole
456program.
457
458You might also think of C<throw> as being the moral equivalent of
459C<kill>ing a coroutine with a signal (in this case, a scalar).
460
443=item $coroutine->join 461=item $coroutine->join
444 462
445Wait until the coroutine terminates and return any values given to the 463Wait until the coroutine terminates and return any values given to the
446C<terminate> or C<cancel> functions. C<join> can be called concurrently 464C<terminate> or C<cancel> functions. C<join> can be called concurrently
447from multiple coroutines, and all will be resumed and given the status 465from multiple coroutines, and all will be resumed and given the status
508higher values mean lower priority, just as in unix). 526higher values mean lower priority, just as in unix).
509 527
510=item $olddesc = $coroutine->desc ($newdesc) 528=item $olddesc = $coroutine->desc ($newdesc)
511 529
512Sets (or gets in case the argument is missing) the description for this 530Sets (or gets in case the argument is missing) the description for this
513coroutine. This is just a free-form string you can associate with a coroutine. 531coroutine. This is just a free-form string you can associate with a
532coroutine.
514 533
515This method simply sets the C<< $coroutine->{desc} >> member to the given string. You 534This method simply sets the C<< $coroutine->{desc} >> member to the given
516can modify this member directly if you wish. 535string. You can modify this member directly if you wish.
517
518=item $coroutine->throw ([$scalar])
519
520If C<$throw> is specified and defined, it will be thrown as an exception
521inside the coroutine at the next convinient point in time (usually after
522it gains control at the next schedule/transfer/cede). Otherwise clears the
523exception object.
524
525The exception object will be thrown "as is" with the specified scalar in
526C<$@>, i.e. if it is a string, no line number or newline will be appended
527(unlike with C<die>).
528
529This can be used as a softer means than C<cancel> to ask a coroutine to
530end itself, although there is no guarentee that the exception will lead to
531termination, and if the exception isn't caught it might well end the whole
532program.
533 536
534=cut 537=cut
535 538
536sub desc { 539sub desc {
537 my $old = $_[0]{desc}; 540 my $old = $_[0]{desc};
639 cede; # for short-lived callbacks, this reduces pressure on the coro pool 642 cede; # for short-lived callbacks, this reduces pressure on the coro pool
640 } 643 }
641 schedule; # sleep well 644 schedule; # sleep well
642 } 645 }
643}; 646};
644$unblock_scheduler->desc ("[unblock_sub scheduler]"); 647$unblock_scheduler->{desc} = "[unblock_sub scheduler]";
645 648
646sub unblock_sub(&) { 649sub unblock_sub(&) {
647 my $cb = shift; 650 my $cb = shift;
648 651
649 sub { 652 sub {
658 661
6591; 6621;
660 663
661=head1 BUGS/LIMITATIONS 664=head1 BUGS/LIMITATIONS
662 665
666=over 4
667
668=item fork with pthread backend
669
670When Coro is compiled using the pthread backend (which isn't recommended
671but required on many BSDs as their libcs are completely broken), then
672coroutines will not survive a fork. There is no known workaround except to
673fix your libc and use a saner backend.
674
675=item perl process emulation ("threads")
676
663This module is not perl-pseudo-thread-safe. You should only ever use this 677This module is not perl-pseudo-thread-safe. You should only ever use this
664module from the same thread (this requirement might be removed in the 678module from the same thread (this requirement might be removed in the
665future to allow per-thread schedulers, but Coro::State does not yet allow 679future to allow per-thread schedulers, but Coro::State does not yet allow
666this). I recommend disabling thread support and using processes, as this 680this). I recommend disabling thread support and using processes, as having
667is much faster and uses less memory. 681the windows process emulation enabled under unix roughly halves perl
682performance, even when not used.
683
684=item coroutine switching not signal safe
685
686You must not switch to another coroutine from within a signal handler
687(only relevant with %SIG - most event libraries provide safe signals).
688
689That means you I<MUST NOT> call any function that might "block" the
690current coroutine - C<cede>, C<schedule> C<< Coro::Semaphore->down >> or
691anything that calls those. Everything else, including calling C<ready>,
692works.
693
694=back
695
668 696
669=head1 SEE ALSO 697=head1 SEE ALSO
670 698
671Event-Loop integration: L<Coro::AnyEvent>, L<Coro::EV>, L<Coro::Event>. 699Event-Loop integration: L<Coro::AnyEvent>, L<Coro::EV>, L<Coro::Event>.
672 700

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