[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 1.128 by root, Wed Sep 19 21:39:15 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 $VERSION = '3.7';
56		56
57	our @EXPORT = qw(async cede schedule terminate current unblock_sub);	57	our @EXPORT = qw(async async_pool cede schedule terminate current unblock_sub);
58	our %EXPORT_TAGS = (	58	our %EXPORT_TAGS = (
59	prio => [qw(PRIO_MAX PRIO_HIGH PRIO_NORMAL PRIO_LOW PRIO_IDLE PRIO_MIN)],	59	prio => [qw(PRIO_MAX PRIO_HIGH PRIO_NORMAL PRIO_LOW PRIO_IDLE PRIO_MIN)],
60	);	60	);
61	our @EXPORT_OK = (@{$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...
…		…
141	$idle = sub {	141	$idle = sub {
142	require Carp;	142	require Carp;
143	Carp::croak ("FATAL: deadlock detected");	143	Carp::croak ("FATAL: deadlock detected");
144	};	144	};
145		145
		146	sub _cancel {
		147	my ($self) = @_;
		148
		149	# free coroutine data and mark as destructed
		150	$self->_destroy
		151	or return;
		152
		153	# call all destruction callbacks
		154	$_->(@{$self->{status}})
		155	for @{(delete $self->{destroy_cb}) \|\| []};
		156	}
		157
146	# this coroutine is necessary because a coroutine	158	# this coroutine is necessary because a coroutine
147	# cannot destroy itself.	159	# cannot destroy itself.
148	my @destroy;	160	my @destroy;
		161	my $manager;
		162
149	my $manager; $manager = new Coro sub {	163	$manager = new Coro sub {
150	while () {	164	while () {
151	# by overwriting the state object with the manager we destroy it	165	(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) {	166	while @destroy;
157	my $coro = pop @destroy;
158		167
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;	168	&schedule;
171	}	169	}
172	};	170	};
		171
		172	$manager->prio (PRIO_MAX);
173		173
174	# static methods. not really.	174	# static methods. not really.
175		175
176	=back	176	=back
177		177
…		…
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;
199		198
200	=cut	199	=cut
201		200
202	sub async(&@) {	201	sub async(&@) {
203	my $pid = new Coro @_;	202	my $coro = new Coro @_;
204	$pid->ready;	203	$coro->ready;
205	$pid	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) \|\| do {
		255	my $coro = new Coro \&pool_handler;
		256	$coro->{desc} = "async_pool";
		257	$coro
		258	};
		259
		260	$coro->{_invoke} = [@_];
		261	$coro->ready;
		262
		263	$coro
206	}	264	}
207		265
208	=item schedule	266	=item schedule
209		267
210	Calls the scheduler. Please note that the current coroutine will not be put	268	Calls the scheduler. Please note that the current coroutine will not be put
…		…
223	# wake up sleeping coroutine	281	# wake up sleeping coroutine
224	$current->ready;	282	$current->ready;
225	undef $current;	283	undef $current;
226	};	284	};
227		285
228	# call schedule until event occured.	286	# call schedule until event occurred.
229	# in case we are woken up for other reasons	287	# in case we are woken up for other reasons
230	# (current still defined), loop.	288	# (current still defined), loop.
231	Coro::schedule while $current;	289	Coro::schedule while $current;
232	}	290	}
233		291
234	=item cede	292	=item cede
235		293
236	"Cede" to other coroutines. This function puts the current coroutine into the	294	"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	295	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.	296	current "timeslice" to other coroutines of the same or higher priority.
		297
		298	Returns true if at least one coroutine switch has happened.
		299
		300	=item Coro::cede_notself
		301
		302	Works like cede, but is not exported by default and will cede to any
		303	coroutine, regardless of priority, once.
		304
		305	Returns true if at least one coroutine switch has happened.
239		306
240	=item terminate [arg...]	307	=item terminate [arg...]
241		308
242	Terminates the current coroutine with the given status values (see L<cancel>).	309	Terminates the current coroutine with the given status values (see L<cancel>).
243		310
…		…
262	Create a new coroutine and return it. When the sub returns the coroutine	329	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	330	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	331	called. To make the coroutine run you must first put it into the ready queue
265	by calling the ready method.	332	by calling the ready method.
266		333
267	Calling C<exit> in a coroutine will not work correctly, so do not do that.	334	See C<async> for additional discussion.
268		335
269	=cut	336	=cut
270		337
271	sub _run_coro {	338	sub _run_coro {
272	terminate &{+shift};	339	terminate &{+shift};
…		…
289	Return wether the coroutine is currently the ready queue or not,	356	Return wether the coroutine is currently the ready queue or not,
290		357
291	=item $coroutine->cancel (arg...)	358	=item $coroutine->cancel (arg...)
292		359
293	Terminates the given coroutine and makes it return the given arguments as	360	Terminates the given coroutine and makes it return the given arguments as
294	status (default: the empty list).	361	status (default: the empty list). Never returns if the coroutine is the
		362	current coroutine.
295		363
296	=cut	364	=cut
297		365
298	sub cancel {	366	sub cancel {
299	my $self = shift;	367	my $self = shift;
300	$self->{status} = [@_];	368	$self->{status} = [@_];
		369
		370	if ($current == $self) {
301	push @destroy, $self;	371	push @destroy, $self;
302	$manager->ready;	372	$manager->ready;
303	&schedule if $current == $self;	373	&schedule while 1;
		374	} else {
		375	$self->_cancel;
		376	}
304	}	377	}
305		378
306	=item $coroutine->join	379	=item $coroutine->join
307		380
308	Wait until the coroutine terminates and return any values given to the	381	Wait until the coroutine terminates and return any values given to the
…		…
311		384
312	=cut	385	=cut
313		386
314	sub join {	387	sub join {
315	my $self = shift;	388	my $self = shift;
		389
316	unless ($self->{status}) {	390	unless ($self->{status}) {
317	push @{$self->{join}}, $current;	391	my $current = $current;
318	&schedule;	392
		393	push @{$self->{destroy_cb}}, sub {
		394	$current->ready;
		395	undef $current;
		396	};
		397
		398	&schedule while $current;
319	}	399	}
		400
320	wantarray ? @{$self->{status}} : $self->{status}[0];	401	wantarray ? @{$self->{status}} : $self->{status}[0];
321	}	402	}
322		403
323	=item $coroutine->on_destroy (\&cb)	404	=item $coroutine->on_destroy (\&cb)
324		405
…		…
381	=over 4	462	=over 4
382		463
383	=item Coro::nready	464	=item Coro::nready
384		465
385	Returns the number of coroutines that are currently in the ready state,	466	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	467	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,	468	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	469	and C<schedule> would cause a deadlock unless there is an idle handler
389	that wakes up some coroutines.	470	that wakes up some coroutines.
		471
		472	=item my $guard = Coro::guard { ... }
		473
		474	This creates and returns a guard object. Nothing happens until the object
		475	gets destroyed, in which case the codeblock given as argument will be
		476	executed. This is useful to free locks or other resources in case of a
		477	runtime error or when the coroutine gets canceled, as in both cases the
		478	guard block will be executed. The guard object supports only one method,
		479	C<< ->cancel >>, which will keep the codeblock from being executed.
		480
		481	Example: set some flag and clear it again when the coroutine gets canceled
		482	or the function returns:
		483
		484	sub do_something {
		485	my $guard = Coro::guard { $busy = 0 };
		486	$busy = 1;
		487
		488	# do something that requires $busy to be true
		489	}
		490
		491	=cut
		492
		493	sub guard(&) {
		494	bless \(my $cb = $_[0]), "Coro::guard"
		495	}
		496
		497	sub Coro::guard::cancel {
		498	${$_[0]} = sub { };
		499	}
		500
		501	sub Coro::guard::DESTROY {
		502	${$_[0]}->();
		503	}
		504
390		505
391	=item unblock_sub { ... }	506	=item unblock_sub { ... }
392		507
393	This utility function takes a BLOCK or code reference and "unblocks" it,	508	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	509	returning the new coderef. This means that the new coderef will return
395	immediately without blocking, returning nothing, while the original code	510	immediately without blocking, returning nothing, while the original code
396	ref will be called (with parameters) from within its own coroutine.	511	ref will be called (with parameters) from within its own coroutine.
397		512
398	The reason this fucntion exists is that many event libraries (such as the	513	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	514	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,	515	of thread-safety). This means you must not block within event callbacks,
401	otherwise you might suffer from crashes or worse.	516	otherwise you might suffer from crashes or worse.
402		517
403	This function allows your callbacks to block by executing them in another	518	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	523	In short: simply use C<unblock_sub { ... }> instead of C<sub { ... }> when
409	creating event callbacks that want to block.	524	creating event callbacks that want to block.
410		525
411	=cut	526	=cut
412		527
413	our @unblock_pool;
414	our @unblock_queue;	528	our @unblock_queue;
415	our $UNBLOCK_POOL_SIZE = 2;
416		529
417	sub unblock_handler_ {	530	# we create a special coro because we want to cede,
418	while () {	531	# to reduce pressure on the coro pool (because most callbacks
419	my ($cb, @arg) = @{ delete $Coro::current->{arg} };	532	# return immediately and can be reused) and because we cannot cede
420	$cb->(@arg);	533	# 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 {	534	our $unblock_scheduler = async {
429	while () {	535	while () {
430	while (my $cb = pop @unblock_queue) {	536	while (my $cb = pop @unblock_queue) {
		537	# this is an inlined copy of async_pool
431	my $handler = (pop @unblock_pool or new Coro \&unblock_handler_);	538	my $coro = (pop @pool or new Coro \&pool_handler);
432	$handler->{arg} = $cb;	539
		540	$coro->{_invoke} = $cb;
433	$handler->ready;	541	$coro->ready;
434	cede;	542	cede; # for short-lived callbacks, this reduces pressure on the coro pool
435	}	543	}
436		544	schedule; # sleep well
437	schedule;
438	}	545	}
439	};	546	};
440		547
441	sub unblock_sub(&) {	548	sub unblock_sub(&) {
442	my $cb = shift;	549	my $cb = shift;
443		550
444	sub {	551	sub {
445	push @unblock_queue, [$cb, @_];	552	unshift @unblock_queue, [$cb, @_];
446	$unblock_scheduler->ready;	553	$unblock_scheduler->ready;
447	}	554	}
448	}	555	}
449		556
450	=back	557	=back
…		…
457		564
458	- you must make very sure that no coro is still active on global	565	- you must make very sure that no coro is still active on global
459	destruction. very bad things might happen otherwise (usually segfaults).	566	destruction. very bad things might happen otherwise (usually segfaults).
460		567
461	- this module is not thread-safe. You should only ever use this module	568	- 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	569	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	570	to allow per-thread schedulers, but Coro::State does not yet allow
464	this).	571	this).
465		572
466	=head1 SEE ALSO	573	=head1 SEE ALSO
467		574

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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 1.128 by root, Wed Sep 19 21:39:15 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 1.128 by root, Wed Sep 19 21:39:15 2007 UTC