[ViewVC] Diff of: cvs/Coro/Coro.pm

Comparing Coro/Coro.pm (file contents):
Revision 1.104 by root, Thu Jan 4 23:49:27 2007 UTC vs.
Revision 1.124 by root, Thu Apr 19 10:37:26 2007 UTC

…		…
20		20
21	=head1 DESCRIPTION	21	=head1 DESCRIPTION
22		22
23	This module collection manages coroutines. Coroutines are similar	23	This module collection manages coroutines. Coroutines are similar
24	to threads but don't run in parallel at the same time even on SMP	24	to threads but don't run in parallel at the same time even on SMP
25	machines. The specific flavor of coroutine use din this module also	25	machines. The specific flavor of coroutine used in this module also
26	guarentees you that it will not switch between coroutines unless	26	guarantees you that it will not switch between coroutines unless
27	necessary, at easily-identified points in your program, so locking and	27	necessary, at easily-identified points in your program, so locking and
28	parallel access are rarely an issue, making coroutine programming much	28	parallel access are rarely an issue, making coroutine programming much
29	safer than threads programming.	29	safer 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
51	our $idle; # idle handler	51	our $idle; # idle handler
52	our $main; # main coroutine	52	our $main; # main coroutine
53	our $current; # current coroutine	53	our $current; # current coroutine
54		54
55	our $VERSION = '3.3';	55	our $VERSION = '3.61';
56		56
57	our @EXPORT = qw(async cede schedule terminate current unblock_sub);	57	our @EXPORT = qw(async async_pool cede schedule terminate current unblock_sub);
58	our %EXPORT_TAGS = (	58	our %EXPORT_TAGS = (
59	prio => [qw(PRIO_MAX PRIO_HIGH PRIO_NORMAL PRIO_LOW PRIO_IDLE PRIO_MIN)],	59	prio => [qw(PRIO_MAX PRIO_HIGH PRIO_NORMAL PRIO_LOW PRIO_IDLE PRIO_MIN)],
60	);	60	);
61	our @EXPORT_OK = (@{$EXPORT_TAGS{prio}}, qw(nready));	61	our @EXPORT_OK = (@{$EXPORT_TAGS{prio}}, qw(nready));
62		62
…		…
108		108
109	The current coroutine (the last coroutine switched to). The initial value	109	The current coroutine (the last coroutine switched to). The initial value
110	is C<$main> (of course).	110	is C<$main> (of course).
111		111
112	This variable is B<strictly> I<read-only>. It is provided for performance	112	This variable is B<strictly> I<read-only>. It is provided for performance
113	reasons. If performance is not essentiel you are encouraged to use the	113	reasons. If performance is not essential you are encouraged to use the
114	C<Coro::current> function instead.	114	C<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...
…		…
185		185
186	Create a new asynchronous coroutine and return it's coroutine object	186	Create 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
188	terminated.	188	terminated.
189		189
190	Calling C<exit> in a coroutine will not work correctly, so do not do that.	190	Calling C<exit> in a coroutine will do the same as calling exit outside
191		191	the coroutine. Likewise, when the coroutine dies, the program will exit,
192	When the coroutine dies, the program will exit, just as in the main	192	just as it would in the main program.
193	program.
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;
…		…
200	=cut	199	=cut
201		200
202	sub async(&@) {	201	sub async(&@) {
203	my $coro = new Coro @_;	202	my $coro = new Coro @_;
204	$coro->ready;	203	$coro->ready;
		204	$coro
		205	}
		206
		207	=item async_pool { ... } [@args...]
		208
		209	Similar to C<async>, but uses a coroutine pool, so you should not call
		210	terminate or join (although you are allowed to), and you get a coroutine
		211	that might have executed other code already (which can be good or bad :).
		212
		213	Also, the block is executed in an C<eval> context and a warning will be
		214	issued in case of an exception instead of terminating the program, as
		215	C<async> does. As the coroutine is being reused, stuff like C<on_destroy>
		216	will not work in the expected way, unless you call terminate or cancel,
		217	which somehow defeats the purpose of pooling.
		218
		219	The priority will be reset to C<0> after each job, otherwise the coroutine
		220	will be re-used "as-is".
		221
		222	The pool size is limited to 8 idle coroutines (this can be adjusted by
		223	changing $Coro::POOL_SIZE), and there can be as many non-idle coros as
		224	required.
		225
		226	If you are concerned about pooled coroutines growing a lot because a
		227	single C<async_pool> used a lot of stackspace you can e.g. C<async_pool {
		228	terminate }> once per second or so to slowly replenish the pool.
		229
		230	=cut
		231
		232	our $POOL_SIZE = 8;
		233	our @pool;
		234
		235	sub pool_handler {
		236	while () {
		237	eval {
		238	my ($cb, @arg) = @{ delete $current->{_invoke} or return };
		239	$cb->(@arg);
		240	};
		241	warn $@ if $@;
		242
		243	last if @pool >= $POOL_SIZE;
		244	push @pool, $current;
		245
		246	$current->save (Coro::State::SAVE_DEF);
		247	$current->prio (0);
		248	schedule;
		249	}
		250	}
		251
		252	sub async_pool(&@) {
		253	# this is also inlined into the unlock_scheduler
		254	my $coro = (pop @pool or new Coro \&pool_handler);
		255
		256	$coro->{_invoke} = [@_];
		257	$coro->ready;
		258
205	$coro	259	$coro
206	}	260	}
207		261
208	=item schedule	262	=item schedule
209		263
…		…
223	# wake up sleeping coroutine	277	# wake up sleeping coroutine
224	$current->ready;	278	$current->ready;
225	undef $current;	279	undef $current;
226	};	280	};
227		281
228	# call schedule until event occured.	282	# call schedule until event occurred.
229	# in case we are woken up for other reasons	283	# in case we are woken up for other reasons
230	# (current still defined), loop.	284	# (current still defined), loop.
231	Coro::schedule while $current;	285	Coro::schedule while $current;
232	}	286	}
233		287
…		…
235		289
236	"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
237	ready queue and calls C<schedule>, which has the effect of giving up the	291	ready queue and calls C<schedule>, which has the effect of giving up the
238	current "timeslice" to other coroutines of the same or higher priority.	292	current "timeslice" to other coroutines of the same or higher priority.
239		293
		294	Returns true if at least one coroutine switch has happened.
		295
240	=item Coro::cede_notself	296	=item Coro::cede_notself
241		297
242	Works like cede, but is not exported by default and will cede to any	298	Works like cede, but is not exported by default and will cede to any
243	coroutine, regardless of priority, once.	299	coroutine, regardless of priority, once.
		300
		301	Returns true if at least one coroutine switch has happened.
244		302
245	=item terminate [arg...]	303	=item terminate [arg...]
246		304
247	Terminates the current coroutine with the given status values (see L<cancel>).	305	Terminates the current coroutine with the given status values (see L<cancel>).
248		306
…		…
267	Create a new coroutine and return it. When the sub returns the coroutine	325	Create a new coroutine and return it. When the sub returns the coroutine
268	automatically terminates as if C<terminate> with the returned values were	326	automatically terminates as if C<terminate> with the returned values were
269	called. To make the coroutine run you must first put it into the ready queue	327	called. To make the coroutine run you must first put it into the ready queue
270	by calling the ready method.	328	by calling the ready method.
271		329
272	Calling C<exit> in a coroutine will not work correctly, so do not do that.	330	See C<async> for additional discussion.
273		331
274	=cut	332	=cut
275		333
276	sub _run_coro {	334	sub _run_coro {
277	terminate &{+shift};	335	terminate &{+shift};
…		…
400	=over 4	458	=over 4
401		459
402	=item Coro::nready	460	=item Coro::nready
403		461
404	Returns the number of coroutines that are currently in the ready state,	462	Returns the number of coroutines that are currently in the ready state,
405	i.e. that can be swicthed to. The value C<0> means that the only runnable	463	i.e. that can be switched to. The value C<0> means that the only runnable
406	coroutine is the currently running one, so C<cede> would have no effect,	464	coroutine is the currently running one, so C<cede> would have no effect,
407	and C<schedule> would cause a deadlock unless there is an idle handler	465	and C<schedule> would cause a deadlock unless there is an idle handler
408	that wakes up some coroutines.	466	that wakes up some coroutines.
409		467
410	=item my $guard = Coro::guard { ... }	468	=item my $guard = Coro::guard { ... }
411		469
412	This creates and returns a guard object. Nothing happens until the objetc	470	This creates and returns a guard object. Nothing happens until the object
413	gets destroyed, in which case the codeblock given as argument will be	471	gets destroyed, in which case the codeblock given as argument will be
414	executed. This is useful to free locks or other resources in case of a	472	executed. This is useful to free locks or other resources in case of a
415	runtime error or when the coroutine gets canceled, as in both cases the	473	runtime error or when the coroutine gets canceled, as in both cases the
416	guard block will be executed. The guard object supports only one method,	474	guard block will be executed. The guard object supports only one method,
417	C<< ->cancel >>, which will keep the codeblock from being executed.	475	C<< ->cancel >>, which will keep the codeblock from being executed.
…		…
446	This utility function takes a BLOCK or code reference and "unblocks" it,	504	This utility function takes a BLOCK or code reference and "unblocks" it,
447	returning the new coderef. This means that the new coderef will return	505	returning the new coderef. This means that the new coderef will return
448	immediately without blocking, returning nothing, while the original code	506	immediately without blocking, returning nothing, while the original code
449	ref will be called (with parameters) from within its own coroutine.	507	ref will be called (with parameters) from within its own coroutine.
450		508
451	The reason this fucntion exists is that many event libraries (such as the	509	The reason this function exists is that many event libraries (such as the
452	venerable L<Event\|Event> module) are not coroutine-safe (a weaker form	510	venerable L<Event\|Event> module) are not coroutine-safe (a weaker form
453	of thread-safety). This means you must not block within event callbacks,	511	of thread-safety). This means you must not block within event callbacks,
454	otherwise you might suffer from crashes or worse.	512	otherwise you might suffer from crashes or worse.
455		513
456	This function allows your callbacks to block by executing them in another	514	This function allows your callbacks to block by executing them in another
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461	In short: simply use C<unblock_sub { ... }> instead of C<sub { ... }> when	519	In short: simply use C<unblock_sub { ... }> instead of C<sub { ... }> when
462	creating event callbacks that want to block.	520	creating event callbacks that want to block.
463		521
464	=cut	522	=cut
465		523
466	our @unblock_pool;
467	our @unblock_queue;	524	our @unblock_queue;
468	our $UNBLOCK_POOL_SIZE = 2;
469		525
470	sub unblock_handler_ {	526	# we create a special coro because we want to cede,
471	while () {	527	# to reduce pressure on the coro pool (because most callbacks
472	my ($cb, @arg) = @{ delete $Coro::current->{arg} };	528	# return immediately and can be reused) and because we cannot cede
473	$cb->(@arg);	529	# inside an event callback.
474
475	last if @unblock_pool >= $UNBLOCK_POOL_SIZE;
476	push @unblock_pool, $Coro::current;
477	schedule;
478	}
479	}
480
481	our $unblock_scheduler = async {	530	our $unblock_scheduler = async {
482	while () {	531	while () {
483	while (my $cb = pop @unblock_queue) {	532	while (my $cb = pop @unblock_queue) {
		533	# this is an inlined copy of async_pool
484	my $handler = (pop @unblock_pool or new Coro \&unblock_handler_);	534	my $coro = (pop @pool or new Coro \&pool_handler);
485	$handler->{arg} = $cb;	535
		536	$coro->{_invoke} = $cb;
486	$handler->ready;	537	$coro->ready;
487	cede;	538	cede; # for short-lived callbacks, this reduces pressure on the coro pool
488	}	539	}
489		540	schedule; # sleep well
490	schedule;
491	}	541	}
492	};	542	};
493		543
494	sub unblock_sub(&) {	544	sub unblock_sub(&) {
495	my $cb = shift;	545	my $cb = shift;
496		546
497	sub {	547	sub {
498	push @unblock_queue, [$cb, @_];	548	unshift @unblock_queue, [$cb, @_];
499	$unblock_scheduler->ready;	549	$unblock_scheduler->ready;
500	}	550	}
501	}	551	}
502		552
503	=back	553	=back
…		…
510		560
511	- 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
512	destruction. very bad things might happen otherwise (usually segfaults).	562	destruction. very bad things might happen otherwise (usually segfaults).
513		563
514	- 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
515	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
516	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
517	this).	567	this).
518		568
519	=head1 SEE ALSO	569	=head1 SEE ALSO
520		570

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Comparing Coro/Coro.pm (file contents): Revision 1.104 by root, Thu Jan 4 23:49:27 2007 UTC vs. Revision 1.124 by root, Thu Apr 19 10:37:26 2007 UTC

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Comparing Coro/Coro.pm (file contents):
Revision 1.104 by root, Thu Jan 4 23:49:27 2007 UTC vs.
Revision 1.124 by root, Thu Apr 19 10:37:26 2007 UTC