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Revision 1.107 by root, Fri Jan 5 18:25:51 2007 UTC vs.
Revision 1.129 by root, Wed Sep 19 22:33:08 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 $VERSION = '3.7';
56 56
57our @EXPORT = qw(async async_pool cede schedule terminate current unblock_sub); 57our @EXPORT = qw(async async_pool cede schedule terminate current unblock_sub);
58our %EXPORT_TAGS = ( 58our %EXPORT_TAGS = (
59 prio => [qw(PRIO_MAX PRIO_HIGH PRIO_NORMAL PRIO_LOW PRIO_IDLE PRIO_MIN)], 59 prio => [qw(PRIO_MAX PRIO_HIGH PRIO_NORMAL PRIO_LOW PRIO_IDLE PRIO_MIN)],
60); 60);
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108 108
109The current coroutine (the last coroutine switched to). The initial value 109The current coroutine (the last coroutine switched to). The initial value
110is C<$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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159# cannot destroy itself. 159# cannot destroy itself.
160my @destroy; 160my @destroy;
161my $manager; 161my $manager;
162 162
163$manager = new Coro sub { 163$manager = new Coro sub {
164 $current->desc ("[coro manager]");
165
164 while () { 166 while () {
165 (shift @destroy)->_cancel 167 (shift @destroy)->_cancel
166 while @destroy; 168 while @destroy;
167 169
168 &schedule; 170 &schedule;
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185 187
186Create a new asynchronous coroutine and return it's coroutine object 188Create a new asynchronous coroutine and return it's coroutine object
187(usually unused). When the sub returns the new coroutine is automatically 189(usually unused). When the sub returns the new coroutine is automatically
188terminated. 190terminated.
189 191
190Calling C<exit> in a coroutine will not work correctly, so do not do that. 192Calling C<exit> in a coroutine will do the same as calling exit outside
191 193the coroutine. Likewise, when the coroutine dies, the program will exit,
192When the coroutine dies, the program will exit, just as in the main 194just as it would in the main program.
193program.
194 195
195 # create a new coroutine that just prints its arguments 196 # create a new coroutine that just prints its arguments
196 async { 197 async {
197 print "@_\n"; 198 print "@_\n";
198 } 1,2,3,4; 199 } 1,2,3,4;
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210Similar to C<async>, but uses a coroutine pool, so you should not call 211Similar 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 212terminate 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 :). 213that might have executed other code already (which can be good or bad :).
213 214
214Also, the block is executed in an C<eval> context and a warning will be 215Also, 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. 216issued in case of an exception instead of terminating the program, as
217C<async> does. As the coroutine is being reused, stuff like C<on_destroy>
218will not work in the expected way, unless you call terminate or cancel,
219which somehow defeats the purpose of pooling.
216 220
217The priority will be reset to C<0> after each job, otherwise the coroutine 221The priority will be reset to C<0> after each job, otherwise the coroutine
218will be re-used "as-is". 222will be re-used "as-is".
219 223
220The pool size is limited to 8 idle coroutines (this can be adjusted by 224The pool size is limited to 8 idle coroutines (this can be adjusted by
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230our $POOL_SIZE = 8; 234our $POOL_SIZE = 8;
231our @pool; 235our @pool;
232 236
233sub pool_handler { 237sub pool_handler {
234 while () { 238 while () {
235 my ($cb, @arg) = @{ delete $current->{_invoke} }; 239 $current->{desc} = "[async_pool]";
236 240
237 eval { 241 eval {
242 my ($cb, @arg) = @{ delete $current->{_invoke} or return };
238 $cb->(@arg); 243 $cb->(@arg);
239 }; 244 };
240 warn $@ if $@; 245 warn $@ if $@;
241 246
242 last if @pool >= $POOL_SIZE; 247 last if @pool >= $POOL_SIZE;
248
243 push @pool, $current; 249 push @pool, $current;
244 250 $current->{desc} = "[async_pool idle]";
251 $current->save (Coro::State::SAVE_DEF);
245 $current->prio (0); 252 $current->prio (0);
246 schedule; 253 schedule;
247 } 254 }
248} 255}
249 256
250sub async_pool(&@) { 257sub async_pool(&@) {
251 # this is also inlined into the unlock_scheduler 258 # this is also inlined into the unlock_scheduler
252 my $coro = (pop @pool or new Coro \&pool_handler); 259 my $coro = (pop @pool) || new Coro \&pool_handler;;
253 260
254 $coro->{_invoke} = [@_]; 261 $coro->{_invoke} = [@_];
255 $coro->ready; 262 $coro->ready;
256 263
257 $coro 264 $coro
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275 # wake up sleeping coroutine 282 # wake up sleeping coroutine
276 $current->ready; 283 $current->ready;
277 undef $current; 284 undef $current;
278 }; 285 };
279 286
280 # call schedule until event occured. 287 # call schedule until event occurred.
281 # in case we are woken up for other reasons 288 # in case we are woken up for other reasons
282 # (current still defined), loop. 289 # (current still defined), loop.
283 Coro::schedule while $current; 290 Coro::schedule while $current;
284 } 291 }
285 292
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323Create a new coroutine and return it. When the sub returns the coroutine 330Create a new coroutine and return it. When the sub returns the coroutine
324automatically terminates as if C<terminate> with the returned values were 331automatically terminates as if C<terminate> with the returned values were
325called. To make the coroutine run you must first put it into the ready queue 332called. To make the coroutine run you must first put it into the ready queue
326by calling the ready method. 333by calling the ready method.
327 334
328Calling C<exit> in a coroutine will not work correctly, so do not do that. 335See C<async> for additional discussion.
329 336
330=cut 337=cut
331 338
332sub _run_coro { 339sub _run_coro {
333 terminate &{+shift}; 340 terminate &{+shift};
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456=over 4 463=over 4
457 464
458=item Coro::nready 465=item Coro::nready
459 466
460Returns the number of coroutines that are currently in the ready state, 467Returns the number of coroutines that are currently in the ready state,
461i.e. that can be swicthed to. The value C<0> means that the only runnable 468i.e. that can be switched to. The value C<0> means that the only runnable
462coroutine is the currently running one, so C<cede> would have no effect, 469coroutine is the currently running one, so C<cede> would have no effect,
463and C<schedule> would cause a deadlock unless there is an idle handler 470and C<schedule> would cause a deadlock unless there is an idle handler
464that wakes up some coroutines. 471that wakes up some coroutines.
465 472
466=item my $guard = Coro::guard { ... } 473=item my $guard = Coro::guard { ... }
467 474
468This creates and returns a guard object. Nothing happens until the objetc 475This creates and returns a guard object. Nothing happens until the object
469gets destroyed, in which case the codeblock given as argument will be 476gets destroyed, in which case the codeblock given as argument will be
470executed. This is useful to free locks or other resources in case of a 477executed. This is useful to free locks or other resources in case of a
471runtime error or when the coroutine gets canceled, as in both cases the 478runtime error or when the coroutine gets canceled, as in both cases the
472guard block will be executed. The guard object supports only one method, 479guard block will be executed. The guard object supports only one method,
473C<< ->cancel >>, which will keep the codeblock from being executed. 480C<< ->cancel >>, which will keep the codeblock from being executed.
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502This utility function takes a BLOCK or code reference and "unblocks" it, 509This utility function takes a BLOCK or code reference and "unblocks" it,
503returning the new coderef. This means that the new coderef will return 510returning the new coderef. This means that the new coderef will return
504immediately without blocking, returning nothing, while the original code 511immediately without blocking, returning nothing, while the original code
505ref will be called (with parameters) from within its own coroutine. 512ref will be called (with parameters) from within its own coroutine.
506 513
507The reason this fucntion exists is that many event libraries (such as the 514The reason this function exists is that many event libraries (such as the
508venerable L<Event|Event> module) are not coroutine-safe (a weaker form 515venerable L<Event|Event> module) are not coroutine-safe (a weaker form
509of thread-safety). This means you must not block within event callbacks, 516of thread-safety). This means you must not block within event callbacks,
510otherwise you might suffer from crashes or worse. 517otherwise you might suffer from crashes or worse.
511 518
512This function allows your callbacks to block by executing them in another 519This function allows your callbacks to block by executing them in another
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524# we create a special coro because we want to cede, 531# we create a special coro because we want to cede,
525# to reduce pressure on the coro pool (because most callbacks 532# to reduce pressure on the coro pool (because most callbacks
526# return immediately and can be reused) and because we cannot cede 533# return immediately and can be reused) and because we cannot cede
527# inside an event callback. 534# inside an event callback.
528our $unblock_scheduler = async { 535our $unblock_scheduler = async {
536 $current->desc ("[unblock_sub scheduler]");
529 while () { 537 while () {
530 while (my $cb = pop @unblock_queue) { 538 while (my $cb = pop @unblock_queue) {
531 # this is an inlined copy of async_pool 539 # this is an inlined copy of async_pool
532 my $coro = (pop @pool or new Coro \&pool_handler); 540 my $coro = (pop @pool or new Coro \&pool_handler);
533 541
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558 566
559 - you must make very sure that no coro is still active on global 567 - you must make very sure that no coro is still active on global
560 destruction. very bad things might happen otherwise (usually segfaults). 568 destruction. very bad things might happen otherwise (usually segfaults).
561 569
562 - this module is not thread-safe. You should only ever use this module 570 - this module is not thread-safe. You should only ever use this module
563 from the same thread (this requirement might be losened in the future 571 from the same thread (this requirement might be loosened in the future
564 to allow per-thread schedulers, but Coro::State does not yet allow 572 to allow per-thread schedulers, but Coro::State does not yet allow
565 this). 573 this).
566 574
567=head1 SEE ALSO 575=head1 SEE ALSO
568 576

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