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Revision 1.109 by root, Fri Jan 12 01:15:03 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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233our $POOL_SIZE = 8; 234our $POOL_SIZE = 8;
234our @pool; 235our @pool;
235 236
236sub pool_handler { 237sub pool_handler {
237 while () { 238 while () {
239 $current->{desc} = "[async_pool]";
240
238 eval { 241 eval {
239 my ($cb, @arg) = @{ delete $current->{_invoke} }; 242 my ($cb, @arg) = @{ delete $current->{_invoke} or return };
240 $cb->(@arg); 243 $cb->(@arg);
241 }; 244 };
242 warn $@ if $@; 245 warn $@ if $@;
243 246
244 last if @pool >= $POOL_SIZE; 247 last if @pool >= $POOL_SIZE;
248
245 push @pool, $current; 249 push @pool, $current;
246 250 $current->{desc} = "[async_pool idle]";
251 $current->save (Coro::State::SAVE_DEF);
247 $current->prio (0); 252 $current->prio (0);
248 schedule; 253 schedule;
249 } 254 }
250} 255}
251 256
252sub async_pool(&@) { 257sub async_pool(&@) {
253 # this is also inlined into the unlock_scheduler 258 # this is also inlined into the unlock_scheduler
254 my $coro = (pop @pool or new Coro \&pool_handler); 259 my $coro = (pop @pool) || new Coro \&pool_handler;;
255 260
256 $coro->{_invoke} = [@_]; 261 $coro->{_invoke} = [@_];
257 $coro->ready; 262 $coro->ready;
258 263
259 $coro 264 $coro
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277 # wake up sleeping coroutine 282 # wake up sleeping coroutine
278 $current->ready; 283 $current->ready;
279 undef $current; 284 undef $current;
280 }; 285 };
281 286
282 # call schedule until event occured. 287 # call schedule until event occurred.
283 # in case we are woken up for other reasons 288 # in case we are woken up for other reasons
284 # (current still defined), loop. 289 # (current still defined), loop.
285 Coro::schedule while $current; 290 Coro::schedule while $current;
286 } 291 }
287 292
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325Create 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
326automatically terminates as if C<terminate> with the returned values were 331automatically terminates as if C<terminate> with the returned values were
327called. 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
328by calling the ready method. 333by calling the ready method.
329 334
330Calling C<exit> in a coroutine will not work correctly, so do not do that. 335See C<async> for additional discussion.
331 336
332=cut 337=cut
333 338
334sub _run_coro { 339sub _run_coro {
335 terminate &{+shift}; 340 terminate &{+shift};
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458=over 4 463=over 4
459 464
460=item Coro::nready 465=item Coro::nready
461 466
462Returns the number of coroutines that are currently in the ready state, 467Returns the number of coroutines that are currently in the ready state,
463i.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
464coroutine 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,
465and 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
466that wakes up some coroutines. 471that wakes up some coroutines.
467 472
468=item my $guard = Coro::guard { ... } 473=item my $guard = Coro::guard { ... }
469 474
470This creates and returns a guard object. Nothing happens until the objetc 475This creates and returns a guard object. Nothing happens until the object
471gets destroyed, in which case the codeblock given as argument will be 476gets destroyed, in which case the codeblock given as argument will be
472executed. 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
473runtime 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
474guard block will be executed. The guard object supports only one method, 479guard block will be executed. The guard object supports only one method,
475C<< ->cancel >>, which will keep the codeblock from being executed. 480C<< ->cancel >>, which will keep the codeblock from being executed.
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504This utility function takes a BLOCK or code reference and "unblocks" it, 509This utility function takes a BLOCK or code reference and "unblocks" it,
505returning the new coderef. This means that the new coderef will return 510returning the new coderef. This means that the new coderef will return
506immediately without blocking, returning nothing, while the original code 511immediately without blocking, returning nothing, while the original code
507ref will be called (with parameters) from within its own coroutine. 512ref will be called (with parameters) from within its own coroutine.
508 513
509The 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
510venerable L<Event|Event> module) are not coroutine-safe (a weaker form 515venerable L<Event|Event> module) are not coroutine-safe (a weaker form
511of thread-safety). This means you must not block within event callbacks, 516of thread-safety). This means you must not block within event callbacks,
512otherwise you might suffer from crashes or worse. 517otherwise you might suffer from crashes or worse.
513 518
514This 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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526# we create a special coro because we want to cede, 531# we create a special coro because we want to cede,
527# to reduce pressure on the coro pool (because most callbacks 532# to reduce pressure on the coro pool (because most callbacks
528# return immediately and can be reused) and because we cannot cede 533# return immediately and can be reused) and because we cannot cede
529# inside an event callback. 534# inside an event callback.
530our $unblock_scheduler = async { 535our $unblock_scheduler = async {
536 $current->desc ("[unblock_sub scheduler]");
531 while () { 537 while () {
532 while (my $cb = pop @unblock_queue) { 538 while (my $cb = pop @unblock_queue) {
533 # this is an inlined copy of async_pool 539 # this is an inlined copy of async_pool
534 my $coro = (pop @pool or new Coro \&pool_handler); 540 my $coro = (pop @pool or new Coro \&pool_handler);
535 541
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560 566
561 - 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
562 destruction. very bad things might happen otherwise (usually segfaults). 568 destruction. very bad things might happen otherwise (usually segfaults).
563 569
564 - 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
565 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
566 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
567 this). 573 this).
568 574
569=head1 SEE ALSO 575=head1 SEE ALSO
570 576

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