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Revision 1.105 by root, Fri Jan 5 16:55:01 2007 UTC vs.
Revision 1.124 by root, Thu Apr 19 10:37:26 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 = '3.3'; 55our $VERSION = '3.61';
56 56
57our @EXPORT = qw(async async_pool cede schedule terminate current unblock_sub); 57our @EXPORT = qw(async async_pool cede schedule terminate current unblock_sub);
58our %EXPORT_TAGS = ( 58our %EXPORT_TAGS = (
59 prio => [qw(PRIO_MAX PRIO_HIGH PRIO_NORMAL PRIO_LOW PRIO_IDLE PRIO_MIN)], 59 prio => [qw(PRIO_MAX PRIO_HIGH PRIO_NORMAL PRIO_LOW PRIO_IDLE PRIO_MIN)],
60); 60);
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108 108
109The current coroutine (the last coroutine switched to). The initial value 109The current coroutine (the last coroutine switched to). The initial value
110is C<$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# maybe some other module used Coro::Specific before... 118# maybe some other module used Coro::Specific before...
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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 do the same as calling exit outside
191 191the coroutine. Likewise, when the coroutine dies, the program will exit,
192When the coroutine dies, the program will exit, just as in the main 192just as it would in the main program.
193program.
194 193
195 # create a new coroutine that just prints its arguments 194 # create a new coroutine that just prints its arguments
196 async { 195 async {
197 print "@_\n"; 196 print "@_\n";
198 } 1,2,3,4; 197 } 1,2,3,4;
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210Similar to C<async>, but uses a coroutine pool, so you should not call 209Similar 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 210terminate 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 :). 211that might have executed other code already (which can be good or bad :).
213 212
214Also, the block is executed in an C<eval> context and a warning will be 213Also, 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. 214issued in case of an exception instead of terminating the program, as
215C<async> does. As the coroutine is being reused, stuff like C<on_destroy>
216will not work in the expected way, unless you call terminate or cancel,
217which somehow defeats the purpose of pooling.
216 218
217The priority will be reset to C<0> after each job, otherwise the coroutine 219The priority will be reset to C<0> after each job, otherwise the coroutine
218will be re-used "as-is". 220will be re-used "as-is".
219 221
220The pool size is limited to 8 idle coroutines (this can be adjusted by 222The pool size is limited to 8 idle coroutines (this can be adjusted by
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230our $POOL_SIZE = 8; 232our $POOL_SIZE = 8;
231our @pool; 233our @pool;
232 234
233sub pool_handler { 235sub pool_handler {
234 while () { 236 while () {
235 my ($cb, @arg) = @{ delete $current->{_invoke} };
236
237 eval { 237 eval {
238 my ($cb, @arg) = @{ delete $current->{_invoke} or return };
238 $cb->(@arg); 239 $cb->(@arg);
239 }; 240 };
240 warn $@ if $@; 241 warn $@ if $@;
241 242
242 last if @pool >= $POOL_SIZE; 243 last if @pool >= $POOL_SIZE;
243 push @pool, $current; 244 push @pool, $current;
244 245
246 $current->save (Coro::State::SAVE_DEF);
245 $current->prio (0); 247 $current->prio (0);
246 schedule; 248 schedule;
247 } 249 }
248} 250}
249 251
250sub async_pool(&@) { 252sub async_pool(&@) {
251 # this is also inlined into the unlock_scheduler 253 # this is also inlined into the unlock_scheduler
252 my $coro = (pop @pool or new Coro \&pool_handler); 254 my $coro = (pop @pool or new Coro \&pool_handler);
253 255
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275 # wake up sleeping coroutine 277 # wake up sleeping coroutine
276 $current->ready; 278 $current->ready;
277 undef $current; 279 undef $current;
278 }; 280 };
279 281
280 # call schedule until event occured. 282 # call schedule until event occurred.
281 # in case we are woken up for other reasons 283 # in case we are woken up for other reasons
282 # (current still defined), loop. 284 # (current still defined), loop.
283 Coro::schedule while $current; 285 Coro::schedule while $current;
284 } 286 }
285 287
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287 289
288"Cede" to other coroutines. This function puts the current coroutine into the 290"Cede" to other coroutines. This function puts the current coroutine into the
289ready queue and calls C<schedule>, which has the effect of giving up the 291ready queue and calls C<schedule>, which has the effect of giving up the
290current "timeslice" to other coroutines of the same or higher priority. 292current "timeslice" to other coroutines of the same or higher priority.
291 293
294Returns true if at least one coroutine switch has happened.
295
292=item Coro::cede_notself 296=item Coro::cede_notself
293 297
294Works like cede, but is not exported by default and will cede to any 298Works like cede, but is not exported by default and will cede to any
295coroutine, regardless of priority, once. 299coroutine, regardless of priority, once.
300
301Returns true if at least one coroutine switch has happened.
296 302
297=item terminate [arg...] 303=item terminate [arg...]
298 304
299Terminates the current coroutine with the given status values (see L<cancel>). 305Terminates the current coroutine with the given status values (see L<cancel>).
300 306
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319Create a new coroutine and return it. When the sub returns the coroutine 325Create a new coroutine and return it. When the sub returns the coroutine
320automatically terminates as if C<terminate> with the returned values were 326automatically terminates as if C<terminate> with the returned values were
321called. To make the coroutine run you must first put it into the ready queue 327called. To make the coroutine run you must first put it into the ready queue
322by calling the ready method. 328by calling the ready method.
323 329
324Calling C<exit> in a coroutine will not work correctly, so do not do that. 330See C<async> for additional discussion.
325 331
326=cut 332=cut
327 333
328sub _run_coro { 334sub _run_coro {
329 terminate &{+shift}; 335 terminate &{+shift};
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452=over 4 458=over 4
453 459
454=item Coro::nready 460=item Coro::nready
455 461
456Returns the number of coroutines that are currently in the ready state, 462Returns the number of coroutines that are currently in the ready state,
457i.e. that can be swicthed to. The value C<0> means that the only runnable 463i.e. that can be switched to. The value C<0> means that the only runnable
458coroutine is the currently running one, so C<cede> would have no effect, 464coroutine is the currently running one, so C<cede> would have no effect,
459and C<schedule> would cause a deadlock unless there is an idle handler 465and C<schedule> would cause a deadlock unless there is an idle handler
460that wakes up some coroutines. 466that wakes up some coroutines.
461 467
462=item my $guard = Coro::guard { ... } 468=item my $guard = Coro::guard { ... }
463 469
464This creates and returns a guard object. Nothing happens until the objetc 470This creates and returns a guard object. Nothing happens until the object
465gets destroyed, in which case the codeblock given as argument will be 471gets 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 472executed. 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 473runtime error or when the coroutine gets canceled, as in both cases the
468guard block will be executed. The guard object supports only one method, 474guard block will be executed. The guard object supports only one method,
469C<< ->cancel >>, which will keep the codeblock from being executed. 475C<< ->cancel >>, which will keep the codeblock from being executed.
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498This utility function takes a BLOCK or code reference and "unblocks" it, 504This utility function takes a BLOCK or code reference and "unblocks" it,
499returning the new coderef. This means that the new coderef will return 505returning the new coderef. This means that the new coderef will return
500immediately without blocking, returning nothing, while the original code 506immediately without blocking, returning nothing, while the original code
501ref will be called (with parameters) from within its own coroutine. 507ref will be called (with parameters) from within its own coroutine.
502 508
503The reason this fucntion exists is that many event libraries (such as the 509The reason this function exists is that many event libraries (such as the
504venerable L<Event|Event> module) are not coroutine-safe (a weaker form 510venerable L<Event|Event> module) are not coroutine-safe (a weaker form
505of thread-safety). This means you must not block within event callbacks, 511of thread-safety). This means you must not block within event callbacks,
506otherwise you might suffer from crashes or worse. 512otherwise you might suffer from crashes or worse.
507 513
508This function allows your callbacks to block by executing them in another 514This function allows your callbacks to block by executing them in another
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554 560
555 - you must make very sure that no coro is still active on global 561 - you must make very sure that no coro is still active on global
556 destruction. very bad things might happen otherwise (usually segfaults). 562 destruction. very bad things might happen otherwise (usually segfaults).
557 563
558 - this module is not thread-safe. You should only ever use this module 564 - this module is not thread-safe. You should only ever use this module
559 from the same thread (this requirement might be losened in the future 565 from the same thread (this requirement might be loosened in the future
560 to allow per-thread schedulers, but Coro::State does not yet allow 566 to allow per-thread schedulers, but Coro::State does not yet allow
561 this). 567 this).
562 568
563=head1 SEE ALSO 569=head1 SEE ALSO
564 570

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