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

Comparing Coro/Coro.pm (file contents):
Revision 1.101 by root, Fri Dec 29 08:36:34 2006 UTC vs.
Revision 1.140 by root, Thu Sep 27 16:25:10 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
…		…
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 $VERSION = '3.8';
56		56
57	our @EXPORT = qw(async cede schedule terminate current unblock_sub);	57	our @EXPORT = qw(async async_pool cede schedule terminate current unblock_sub);
58	our %EXPORT_TAGS = (	58	our %EXPORT_TAGS = (
59	prio => [qw(PRIO_MAX PRIO_HIGH PRIO_NORMAL PRIO_LOW PRIO_IDLE PRIO_MIN)],	59	prio => [qw(PRIO_MAX PRIO_HIGH PRIO_NORMAL PRIO_LOW PRIO_IDLE PRIO_MIN)],
60	);	60	);
61	our @EXPORT_OK = (@{$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
		118	$main->{desc} = "[main::]";
117		119
118	# maybe some other module used Coro::Specific before...	120	# maybe some other module used Coro::Specific before...
119	$main->{specific} = $current->{specific}	121	$main->{specific} = $current->{specific}
120	if $current;	122	if $current;
121		123
…		…
141	$idle = sub {	143	$idle = sub {
142	require Carp;	144	require Carp;
143	Carp::croak ("FATAL: deadlock detected");	145	Carp::croak ("FATAL: deadlock detected");
144	};	146	};
145		147
		148	sub _cancel {
		149	my ($self) = @_;
		150
		151	# free coroutine data and mark as destructed
		152	$self->_destroy
		153	or return;
		154
		155	# call all destruction callbacks
		156	$_->(@{$self->{status}})
		157	for @{(delete $self->{destroy_cb}) \|\| []};
		158	}
		159
146	# this coroutine is necessary because a coroutine	160	# this coroutine is necessary because a coroutine
147	# cannot destroy itself.	161	# cannot destroy itself.
148	my @destroy;	162	my @destroy;
		163	my $manager;
		164
149	my $manager; $manager = new Coro sub {	165	$manager = new Coro sub {
150	while () {	166	while () {
151	# by overwriting the state object with the manager we destroy it	167	(shift @destroy)->_cancel
152	# while still being able to schedule this coroutine (in case it has
153	# been readied multiple times. this is harmless since the manager
154	# can be called as many times as neccessary and will always
155	# remove itself from the runqueue
156	while (@destroy) {	168	while @destroy;
157	my $coro = pop @destroy;
158		169
159	$coro->{status} \|\|= [];
160
161	$_->ready for @{(delete $coro->{join} ) \|\| []};
162	$_->(@{$coro->{status}}) for @{(delete $coro->{destroy_cb}) \|\| []};
163
164	# the next line destroys the coro state, but keeps the
165	# coroutine itself intact (we basically make it a zombie
166	# coroutine that always runs the manager thread, so it's possible
167	# to transfer() to this coroutine).
168	$coro->_clone_state_from ($manager);
169	}
170	&schedule;	170	&schedule;
171	}	171	}
172	};	172	};
		173	$manager->desc ("[coro manager]");
		174	$manager->prio (PRIO_MAX);
173		175
174	# static methods. not really.	176	# static methods. not really.
175		177
176	=back	178	=back
177		179
…		…
185		187
186	Create a new asynchronous coroutine and return it's coroutine object	188	Create 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
188	terminated.	190	terminated.
189		191
190	Calling C<exit> in a coroutine will not work correctly, so do not do that.	192	Calling C<exit> in a coroutine will do the same as calling exit outside
191		193	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	194	just as it would in the main program.
193	program.
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;
199		200
200	=cut	201	=cut
201		202
202	sub async(&@) {	203	sub async(&@) {
203	my $pid = new Coro @_;	204	my $coro = new Coro @_;
204	$pid->ready;	205	$coro->ready;
205	$pid	206	$coro
		207	}
		208
		209	=item async_pool { ... } [@args...]
		210
		211	Similar to C<async>, but uses a coroutine pool, so you should not call
		212	terminate or join (although you are allowed to), and you get a coroutine
		213	that might have executed other code already (which can be good or bad :).
		214
		215	Also, the block is executed in an C<eval> context and a warning will be
		216	issued in case of an exception instead of terminating the program, as
		217	C<async> does. As the coroutine is being reused, stuff like C<on_destroy>
		218	will not work in the expected way, unless you call terminate or cancel,
		219	which somehow defeats the purpose of pooling.
		220
		221	The priority will be reset to C<0> after each job, otherwise the coroutine
		222	will be re-used "as-is".
		223
		224	The pool size is limited to 8 idle coroutines (this can be adjusted by
		225	changing $Coro::POOL_SIZE), and there can be as many non-idle coros as
		226	required.
		227
		228	If you are concerned about pooled coroutines growing a lot because a
		229	single C<async_pool> used a lot of stackspace you can e.g. C<async_pool
		230	{ terminate }> once per second or so to slowly replenish the pool. In
		231	addition to that, when the stacks used by a handler grows larger than 16kb
		232	(adjustable with $Coro::POOL_RSS) it will also exit.
		233
		234	=cut
		235
		236	our $POOL_SIZE = 8;
		237	our $POOL_RSS = 16 * 1024;
		238	our @async_pool;
		239
		240	sub pool_handler {
		241	my $cb;
		242
		243	while () {
		244	eval {
		245	while () {
		246	_pool_1 $cb;
		247	&$cb;
		248	_pool_2 $cb;
		249	&schedule;
		250	}
		251	};
		252
		253	last if $@ eq "\3terminate\2\n";
		254	warn $@ if $@;
		255	}
		256	}
		257
		258	sub async_pool(&@) {
		259	# this is also inlined into the unlock_scheduler
		260	my $coro = (pop @async_pool) \|\| new Coro \&pool_handler;
		261
		262	$coro->{_invoke} = [@_];
		263	$coro->ready;
		264
		265	$coro
206	}	266	}
207		267
208	=item schedule	268	=item schedule
209		269
210	Calls the scheduler. Please note that the current coroutine will not be put	270	Calls the scheduler. Please note that the current coroutine will not be put
…		…
223	# wake up sleeping coroutine	283	# wake up sleeping coroutine
224	$current->ready;	284	$current->ready;
225	undef $current;	285	undef $current;
226	};	286	};
227		287
228	# call schedule until event occured.	288	# call schedule until event occurred.
229	# in case we are woken up for other reasons	289	# in case we are woken up for other reasons
230	# (current still defined), loop.	290	# (current still defined), loop.
231	Coro::schedule while $current;	291	Coro::schedule while $current;
232	}	292	}
233		293
234	=item cede	294	=item cede
235		295
236	"Cede" to other coroutines. This function puts the current coroutine into the	296	"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	297	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.	298	current "timeslice" to other coroutines of the same or higher priority.
		299
		300	Returns true if at least one coroutine switch has happened.
		301
		302	=item Coro::cede_notself
		303
		304	Works like cede, but is not exported by default and will cede to any
		305	coroutine, regardless of priority, once.
		306
		307	Returns true if at least one coroutine switch has happened.
239		308
240	=item terminate [arg...]	309	=item terminate [arg...]
241		310
242	Terminates the current coroutine with the given status values (see L<cancel>).	311	Terminates the current coroutine with the given status values (see L<cancel>).
243		312
…		…
262	Create a new coroutine and return it. When the sub returns the coroutine	331	Create a new coroutine and return it. When the sub returns the coroutine
263	automatically terminates as if C<terminate> with the returned values were	332	automatically terminates as if C<terminate> with the returned values were
264	called. To make the coroutine run you must first put it into the ready queue	333	called. To make the coroutine run you must first put it into the ready queue
265	by calling the ready method.	334	by calling the ready method.
266		335
267	Calling C<exit> in a coroutine will not work correctly, so do not do that.	336	See C<async> for additional discussion.
268		337
269	=cut	338	=cut
270		339
271	sub _run_coro {	340	sub _run_coro {
272	terminate &{+shift};	341	terminate &{+shift};
…		…
289	Return wether the coroutine is currently the ready queue or not,	358	Return wether the coroutine is currently the ready queue or not,
290		359
291	=item $coroutine->cancel (arg...)	360	=item $coroutine->cancel (arg...)
292		361
293	Terminates the given coroutine and makes it return the given arguments as	362	Terminates the given coroutine and makes it return the given arguments as
294	status (default: the empty list).	363	status (default: the empty list). Never returns if the coroutine is the
		364	current coroutine.
295		365
296	=cut	366	=cut
297		367
298	sub cancel {	368	sub cancel {
299	my $self = shift;	369	my $self = shift;
300	$self->{status} = [@_];	370	$self->{status} = [@_];
		371
		372	if ($current == $self) {
301	push @destroy, $self;	373	push @destroy, $self;
302	$manager->ready;	374	$manager->ready;
303	&schedule if $current == $self;	375	&schedule while 1;
		376	} else {
		377	$self->_cancel;
		378	}
304	}	379	}
305		380
306	=item $coroutine->join	381	=item $coroutine->join
307		382
308	Wait until the coroutine terminates and return any values given to the	383	Wait until the coroutine terminates and return any values given to the
…		…
311		386
312	=cut	387	=cut
313		388
314	sub join {	389	sub join {
315	my $self = shift;	390	my $self = shift;
		391
316	unless ($self->{status}) {	392	unless ($self->{status}) {
317	push @{$self->{join}}, $current;	393	my $current = $current;
318	&schedule;	394
		395	push @{$self->{destroy_cb}}, sub {
		396	$current->ready;
		397	undef $current;
		398	};
		399
		400	&schedule while $current;
319	}	401	}
		402
320	wantarray ? @{$self->{status}} : $self->{status}[0];	403	wantarray ? @{$self->{status}} : $self->{status}[0];
321	}	404	}
322		405
323	=item $coroutine->on_destroy (\&cb)	406	=item $coroutine->on_destroy (\&cb)
324		407
…		…
381	=over 4	464	=over 4
382		465
383	=item Coro::nready	466	=item Coro::nready
384		467
385	Returns the number of coroutines that are currently in the ready state,	468	Returns the number of coroutines that are currently in the ready state,
386	i.e. that can be swicthed to. The value C<0> means that the only runnable	469	i.e. that can be switched to. The value C<0> means that the only runnable
387	coroutine is the currently running one, so C<cede> would have no effect,	470	coroutine is the currently running one, so C<cede> would have no effect,
388	and C<schedule> would cause a deadlock unless there is an idle handler	471	and C<schedule> would cause a deadlock unless there is an idle handler
389	that wakes up some coroutines.	472	that wakes up some coroutines.
		473
		474	=item my $guard = Coro::guard { ... }
		475
		476	This creates and returns a guard object. Nothing happens until the object
		477	gets destroyed, in which case the codeblock given as argument will be
		478	executed. This is useful to free locks or other resources in case of a
		479	runtime error or when the coroutine gets canceled, as in both cases the
		480	guard block will be executed. The guard object supports only one method,
		481	C<< ->cancel >>, which will keep the codeblock from being executed.
		482
		483	Example: set some flag and clear it again when the coroutine gets canceled
		484	or the function returns:
		485
		486	sub do_something {
		487	my $guard = Coro::guard { $busy = 0 };
		488	$busy = 1;
		489
		490	# do something that requires $busy to be true
		491	}
		492
		493	=cut
		494
		495	sub guard(&) {
		496	bless \(my $cb = $_[0]), "Coro::guard"
		497	}
		498
		499	sub Coro::guard::cancel {
		500	${$_[0]} = sub { };
		501	}
		502
		503	sub Coro::guard::DESTROY {
		504	${$_[0]}->();
		505	}
		506
390		507
391	=item unblock_sub { ... }	508	=item unblock_sub { ... }
392		509
393	This utility function takes a BLOCK or code reference and "unblocks" it,	510	This utility function takes a BLOCK or code reference and "unblocks" it,
394	returning the new coderef. This means that the new coderef will return	511	returning the new coderef. This means that the new coderef will return
395	immediately without blocking, returning nothing, while the original code	512	immediately without blocking, returning nothing, while the original code
396	ref will be called (with parameters) from within its own coroutine.	513	ref will be called (with parameters) from within its own coroutine.
397		514
398	The reason this fucntion exists is that many event libraries (such as the	515	The reason this function exists is that many event libraries (such as the
399	venerable L<Event\|Event> module) are not coroutine-safe (a weaker form	516	venerable L<Event\|Event> module) are not coroutine-safe (a weaker form
400	of thread-safety). This means you must not block within event callbacks,	517	of thread-safety). This means you must not block within event callbacks,
401	otherwise you might suffer from crashes or worse.	518	otherwise you might suffer from crashes or worse.
402		519
403	This function allows your callbacks to block by executing them in another	520	This function allows your callbacks to block by executing them in another
…		…
408	In short: simply use C<unblock_sub { ... }> instead of C<sub { ... }> when	525	In short: simply use C<unblock_sub { ... }> instead of C<sub { ... }> when
409	creating event callbacks that want to block.	526	creating event callbacks that want to block.
410		527
411	=cut	528	=cut
412		529
413	our @unblock_pool;
414	our @unblock_queue;	530	our @unblock_queue;
415	our $UNBLOCK_POOL_SIZE = 2;
416		531
417	sub unblock_handler_ {	532	# we create a special coro because we want to cede,
418	while () {	533	# to reduce pressure on the coro pool (because most callbacks
419	my ($cb, @arg) = @{ delete $Coro::current->{arg} };	534	# return immediately and can be reused) and because we cannot cede
420	$cb->(@arg);	535	# inside an event callback.
421
422	last if @unblock_pool >= $UNBLOCK_POOL_SIZE;
423	push @unblock_pool, $Coro::current;
424	schedule;
425	}
426	}
427
428	our $unblock_scheduler = async {	536	our $unblock_scheduler = new Coro sub {
429	while () {	537	while () {
430	while (my $cb = pop @unblock_queue) {	538	while (my $cb = pop @unblock_queue) {
431	my $handler = (pop @unblock_pool or new Coro \&unblock_handler_);	539	# this is an inlined copy of async_pool
432	$handler->{arg} = $cb;	540	my $coro = (pop @async_pool) \|\| new Coro \&pool_handler;
		541
		542	$coro->{_invoke} = $cb;
433	$handler->ready;	543	$coro->ready;
434	cede;	544	cede; # for short-lived callbacks, this reduces pressure on the coro pool
435	}	545	}
436		546	schedule; # sleep well
437	schedule;
438	}	547	}
439	};	548	};
		549	$unblock_scheduler->desc ("[unblock_sub scheduler]");
440		550
441	sub unblock_sub(&) {	551	sub unblock_sub(&) {
442	my $cb = shift;	552	my $cb = shift;
443		553
444	sub {	554	sub {
445	push @unblock_queue, [$cb, @_];	555	unshift @unblock_queue, [$cb, @_];
446	$unblock_scheduler->ready;	556	$unblock_scheduler->ready;
447	}	557	}
448	}	558	}
449		559
450	=back	560	=back
…		…
457		567
458	- you must make very sure that no coro is still active on global	568	- you must make very sure that no coro is still active on global
459	destruction. very bad things might happen otherwise (usually segfaults).	569	destruction. very bad things might happen otherwise (usually segfaults).
460		570
461	- this module is not thread-safe. You should only ever use this module	571	- this module is not thread-safe. You should only ever use this module
462	from the same thread (this requirement might be losened in the future	572	from the same thread (this requirement might be loosened in the future
463	to allow per-thread schedulers, but Coro::State does not yet allow	573	to allow per-thread schedulers, but Coro::State does not yet allow
464	this).	574	this).
465		575
466	=head1 SEE ALSO	576	=head1 SEE ALSO
467		577

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Comparing Coro/Coro.pm (file contents): Revision 1.101 by root, Fri Dec 29 08:36:34 2006 UTC vs. Revision 1.140 by root, Thu Sep 27 16:25:10 2007 UTC

Diff Legend

Comparing Coro/Coro.pm (file contents):
Revision 1.101 by root, Fri Dec 29 08:36:34 2006 UTC vs.
Revision 1.140 by root, Thu Sep 27 16:25:10 2007 UTC