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Comparing cvsroot/Coro/Coro.pm (file contents):
Revision 1.181 by root, Fri May 9 22:04:37 2008 UTC vs.
Revision 1.208 by root, Tue Nov 4 12:08:44 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;
35parallel access are rarely an issue, making coroutine programming much 36parallel access are rarely an issue, making coroutine programming much
36safer and easier than threads programming. 37safer and easier than threads programming.
37 38
38Unlike a normal perl program, however, coroutines allow you to have 39Unlike a normal perl program, however, coroutines allow you to have
39multiple running interpreters that share data, which is especially useful 40multiple running interpreters that share data, which is especially useful
40to code pseudo-parallel processes, such as multiple HTTP-GET requests 41to code pseudo-parallel processes and for event-based programming, such as
41running concurrently. 42multiple HTTP-GET requests running concurrently. See L<Coro::AnyEvent> to
43learn more.
42 44
43Coroutines are also useful because Perl has no support for threads (the so 45Coroutines are also useful because Perl has no support for threads (the so
44called "threads" that perl offers are nothing more than the (bad) process 46called "threads" that perl offers are nothing more than the (bad) process
45emulation coming from the Windows platform: On standard operating systems 47emulation coming from the Windows platform: On standard operating systems
46they serve no purpose whatsoever, except by making your programs slow and 48they serve no purpose whatsoever, except by making your programs slow and
65 67
66our $idle; # idle handler 68our $idle; # idle handler
67our $main; # main coroutine 69our $main; # main coroutine
68our $current; # current coroutine 70our $current; # current coroutine
69 71
70our $VERSION = 4.6; 72our $VERSION = 4.803;
71 73
72our @EXPORT = qw(async async_pool cede schedule terminate current unblock_sub); 74our @EXPORT = qw(async async_pool cede schedule terminate current unblock_sub);
73our %EXPORT_TAGS = ( 75our %EXPORT_TAGS = (
74 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)],
75); 77);
80=item $Coro::main 82=item $Coro::main
81 83
82This variable stores the coroutine object that represents the main 84This variable stores the coroutine object that represents the main
83program. While you cna C<ready> it and do most other things you can do to 85program. While you cna C<ready> it and do most other things you can do to
84coroutines, it is mainly useful to compare again C<$Coro::current>, to see 86coroutines, it is mainly useful to compare again C<$Coro::current>, to see
85wether you are running in the main program or not. 87whether you are running in the main program or not.
86 88
87=cut 89=cut
88 90
89$main = new Coro; 91$main = new Coro;
90 92
166 while @destroy; 168 while @destroy;
167 169
168 &schedule; 170 &schedule;
169 } 171 }
170}; 172};
171$manager->desc ("[coro manager]"); 173$manager->{desc} = "[coro manager]";
172$manager->prio (PRIO_MAX); 174$manager->prio (PRIO_MAX);
173 175
174=back 176=back
175 177
176=head2 SIMPLE COROUTINE CREATION 178=head2 SIMPLE COROUTINE CREATION
219terminate or join on it (although you are allowed to), and you get a 221terminate or join on it (although you are allowed to), and you get a
220coroutine that might have executed other code already (which can be good 222coroutine that might have executed other code already (which can be good
221or bad :). 223or bad :).
222 224
223On the plus side, this function is faster than creating (and destroying) 225On the plus side, this function is faster than creating (and destroying)
224a completely new coroutine, so if you need a lot of generic coroutines in 226a completly new coroutine, so if you need a lot of generic coroutines in
225quick successsion, use C<async_pool>, not C<async>. 227quick successsion, use C<async_pool>, not C<async>.
226 228
227The code block is executed in an C<eval> context and a warning will be 229The code block is executed in an C<eval> context and a warning will be
228issued in case of an exception instead of terminating the program, as 230issued in case of an exception instead of terminating the program, as
229C<async> does. As the coroutine is being reused, stuff like C<on_destroy> 231C<async> does. As the coroutine is being reused, stuff like C<on_destroy>
233 235
234The priority will be reset to C<0> after each run, tracing will be 236The priority will be reset to C<0> after each run, tracing will be
235disabled, the description will be reset and the default output filehandle 237disabled, the description will be reset and the default output filehandle
236gets restored, so you can change all these. Otherwise the coroutine will 238gets restored, so you can change all these. Otherwise the coroutine will
237be re-used "as-is": most notably if you change other per-coroutine global 239be re-used "as-is": most notably if you change other per-coroutine global
238stuff such as C<$/> you I<must needs> to revert that change, which is most 240stuff such as C<$/> you I<must needs> revert that change, which is most
239simply done by using local as in: C< local $/ >. 241simply done by using local as in: C<< local $/ >>.
240 242
241The pool size is limited to C<8> idle coroutines (this can be adjusted by 243The idle pool size is limited to C<8> idle coroutines (this can be
242changing $Coro::POOL_SIZE), and there can be as many non-idle coros as 244adjusted by changing $Coro::POOL_SIZE), but there can be as many non-idle
243required. 245coros as required.
244 246
245If you are concerned about pooled coroutines growing a lot because a 247If you are concerned about pooled coroutines growing a lot because a
246single C<async_pool> used a lot of stackspace you can e.g. C<async_pool 248single C<async_pool> used a lot of stackspace you can e.g. C<async_pool
247{ terminate }> once per second or so to slowly replenish the pool. In 249{ terminate }> once per second or so to slowly replenish the pool. In
248addition to that, when the stacks used by a handler grows larger than 16kb 250addition to that, when the stacks used by a handler grows larger than 16kb
265 _pool_2 $cb; 267 _pool_2 $cb;
266 &schedule; 268 &schedule;
267 } 269 }
268 }; 270 };
269 271
272 if ($@) {
270 last if $@ eq "\3async_pool terminate\2\n"; 273 last if $@ eq "\3async_pool terminate\2\n";
271 warn $@ if $@; 274 warn $@;
275 }
272 } 276 }
273} 277}
274 278
275sub async_pool(&@) { 279sub async_pool(&@) {
276 # this is also inlined into the unlock_scheduler 280 # this is also inlined into the unlock_scheduler
306This makes C<schedule> I<the> generic method to use to block the current 310This makes C<schedule> I<the> generic method to use to block the current
307coroutine and wait for events: first you remember the current coroutine in 311coroutine and wait for events: first you remember the current coroutine in
308a variable, then arrange for some callback of yours to call C<< ->ready 312a variable, then arrange for some callback of yours to call C<< ->ready
309>> on that once some event happens, and last you call C<schedule> to put 313>> on that once some event happens, and last you call C<schedule> to put
310yourself to sleep. Note that a lot of things can wake your coroutine up, 314yourself to sleep. Note that a lot of things can wake your coroutine up,
311so you need to check wether the event indeed happened, e.g. by storing the 315so you need to check whether the event indeed happened, e.g. by storing the
312status in a variable. 316status in a variable.
313 317
314The canonical way to wait on external events is this: 318The canonical way to wait on external events is this:
315 319
316 { 320 {
355Kills/terminates/cancels all coroutines except the currently running 359Kills/terminates/cancels all coroutines except the currently running
356one. This is useful after a fork, either in the child or the parent, as 360one. This is useful after a fork, either in the child or the parent, as
357usually only one of them should inherit the running coroutines. 361usually only one of them should inherit the running coroutines.
358 362
359Note that while this will try to free some of the main programs resources, 363Note that while this will try to free some of the main programs resources,
360you cnanot free all of them, so if a coroutine that is not the main 364you cannot free all of them, so if a coroutine that is not the main
361program calls this function, there will be some one-time resource leak. 365program calls this function, there will be some one-time resource leak.
362 366
363=cut 367=cut
364 368
365sub terminate { 369sub terminate {
414once all the coroutines of higher priority and all coroutines of the same 418once all the coroutines of higher priority and all coroutines of the same
415priority that were put into the ready queue earlier have been resumed. 419priority that were put into the ready queue earlier have been resumed.
416 420
417=item $is_ready = $coroutine->is_ready 421=item $is_ready = $coroutine->is_ready
418 422
419Return wether the coroutine is currently the ready queue or not, 423Return whether the coroutine is currently the ready queue or not,
420 424
421=item $coroutine->cancel (arg...) 425=item $coroutine->cancel (arg...)
422 426
423Terminates the given coroutine and makes it return the given arguments as 427Terminates the given coroutine and makes it return the given arguments as
424status (default: the empty list). Never returns if the coroutine is the 428status (default: the empty list). Never returns if the coroutine is the
437 } else { 441 } else {
438 $self->_cancel; 442 $self->_cancel;
439 } 443 }
440} 444}
441 445
446=item $coroutine->throw ([$scalar])
447
448If C<$throw> is specified and defined, it will be thrown as an exception
449inside the coroutine at the next convenient point in time (usually after
450it gains control at the next schedule/transfer/cede). Otherwise clears the
451exception object.
452
453The exception object will be thrown "as is" with the specified scalar in
454C<$@>, i.e. if it is a string, no line number or newline will be appended
455(unlike with C<die>).
456
457This can be used as a softer means than C<cancel> to ask a coroutine to
458end itself, although there is no guarantee that the exception will lead to
459termination, and if the exception isn't caught it might well end the whole
460program.
461
462You might also think of C<throw> as being the moral equivalent of
463C<kill>ing a coroutine with a signal (in this case, a scalar).
464
442=item $coroutine->join 465=item $coroutine->join
443 466
444Wait until the coroutine terminates and return any values given to the 467Wait until the coroutine terminates and return any values given to the
445C<terminate> or C<cancel> functions. C<join> can be called concurrently 468C<terminate> or C<cancel> functions. C<join> can be called concurrently
446from multiple coroutines, and all will be resumed and given the status 469from multiple coroutines, and all will be resumed and given the status
507higher values mean lower priority, just as in unix). 530higher values mean lower priority, just as in unix).
508 531
509=item $olddesc = $coroutine->desc ($newdesc) 532=item $olddesc = $coroutine->desc ($newdesc)
510 533
511Sets (or gets in case the argument is missing) the description for this 534Sets (or gets in case the argument is missing) the description for this
512coroutine. This is just a free-form string you can associate with a coroutine. 535coroutine. This is just a free-form string you can associate with a
536coroutine.
513 537
514This method simply sets the C<< $coroutine->{desc} >> member to the given string. You 538This method simply sets the C<< $coroutine->{desc} >> member to the given
515can modify this member directly if you wish. 539string. You can modify this member directly if you wish.
516
517=item $coroutine->throw ([$scalar])
518
519If C<$throw> is specified and defined, it will be thrown as an exception
520inside the coroutine at the next convinient point in time (usually after
521it gains control at the next schedule/transfer/cede). Otherwise clears the
522exception object.
523
524The exception object will be thrown "as is" with the specified scalar in
525C<$@>, i.e. if it is a string, no line number or newline will be appended
526(unlike with C<die>).
527
528This can be used as a softer means than C<cancel> to ask a coroutine to
529end itself, although there is no guarentee that the exception will lead to
530termination, and if the exception isn't caught it might well end the whole
531program.
532 540
533=cut 541=cut
534 542
535sub desc { 543sub desc {
536 my $old = $_[0]{desc}; 544 my $old = $_[0]{desc};
610creating event callbacks that want to block. 618creating event callbacks that want to block.
611 619
612If your handler does not plan to block (e.g. simply sends a message to 620If your handler does not plan to block (e.g. simply sends a message to
613another coroutine, or puts some other coroutine into the ready queue), 621another coroutine, or puts some other coroutine into the ready queue),
614there is no reason to use C<unblock_sub>. 622there is no reason to use C<unblock_sub>.
623
624Note that you also need to use C<unblock_sub> for any other callbacks that
625are indirectly executed by any C-based event loop. For example, when you
626use a module that uses L<AnyEvent> (and you use L<Coro::AnyEvent>) and it
627provides callbacks that are the result of some event callback, then you
628must not block either, or use C<unblock_sub>.
615 629
616=cut 630=cut
617 631
618our @unblock_queue; 632our @unblock_queue;
619 633
632 cede; # for short-lived callbacks, this reduces pressure on the coro pool 646 cede; # for short-lived callbacks, this reduces pressure on the coro pool
633 } 647 }
634 schedule; # sleep well 648 schedule; # sleep well
635 } 649 }
636}; 650};
637$unblock_scheduler->desc ("[unblock_sub scheduler]"); 651$unblock_scheduler->{desc} = "[unblock_sub scheduler]";
638 652
639sub unblock_sub(&) { 653sub unblock_sub(&) {
640 my $cb = shift; 654 my $cb = shift;
641 655
642 sub { 656 sub {

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