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

Comparing Coro/Coro.pm (file contents):
Revision 1.92 by root, Fri Dec 1 03:47:55 2006 UTC vs.
Revision 1.105 by root, Fri Jan 5 16:55:01 2007 UTC

…		…
18		18
19	cede;	19	cede;
20		20
21	=head1 DESCRIPTION	21	=head1 DESCRIPTION
22		22
23	This module collection manages coroutines. Coroutines are similar to	23	This module collection manages coroutines. Coroutines are similar
24	threads but don't run in parallel.	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
		26	guarentees you that it will not switch between coroutines unless
		27	necessary, at easily-identified points in your program, so locking and
		28	parallel access are rarely an issue, making coroutine programming much
		29	safer than threads programming.
25		30
		31	(Perl, however, does not natively support real threads but instead does a
		32	very slow and memory-intensive emulation of processes using threads. This
		33	is a performance win on Windows machines, and a loss everywhere else).
		34
26	In this module, coroutines are defined as "callchain + lexical variables	35	In this module, coroutines are defined as "callchain + lexical variables +
27	+ @_ + $_ + $@ + $^W + C stack), that is, a coroutine has it's own	36	@_ + $_ + $@ + $/ + C stack), that is, a coroutine has its own callchain,
28	callchain, it's own set of lexicals and it's own set of perl's most	37	its own set of lexicals and its own set of perls most important global
29	important global variables.	38	variables.
30		39
31	=cut	40	=cut
32		41
33	package Coro;	42	package Coro;
34		43
…		…
41		50
42	our $idle; # idle handler	51	our $idle; # idle handler
43	our $main; # main coroutine	52	our $main; # main coroutine
44	our $current; # current coroutine	53	our $current; # current coroutine
45		54
46	our $VERSION = '3.0';	55	our $VERSION = '3.3';
47		56
48	our @EXPORT = qw(async cede schedule terminate current unblock_sub);	57	our @EXPORT = qw(async async_pool cede schedule terminate current unblock_sub);
49	our %EXPORT_TAGS = (	58	our %EXPORT_TAGS = (
50	prio => [qw(PRIO_MAX PRIO_HIGH PRIO_NORMAL PRIO_LOW PRIO_IDLE PRIO_MIN)],	59	prio => [qw(PRIO_MAX PRIO_HIGH PRIO_NORMAL PRIO_LOW PRIO_IDLE PRIO_MIN)],
51	);	60	);
52	our @EXPORT_OK = @{$EXPORT_TAGS{prio}};	61	our @EXPORT_OK = (@{$EXPORT_TAGS{prio}}, qw(nready));
53		62
54	{	63	{
55	my @async;	64	my @async;
56	my $init;	65	my $init;
57		66
58	# this way of handling attributes simply is NOT scalable ;()	67	# this way of handling attributes simply is NOT scalable ;()
59	sub import {	68	sub import {
60	no strict 'refs';	69	no strict 'refs';
61		70
62	Coro->export_to_level(1, @_);	71	Coro->export_to_level (1, @_);
63		72
64	my $old = *{(caller)[0]."::MODIFY_CODE_ATTRIBUTES"}{CODE};	73	my $old = *{(caller)[0]."::MODIFY_CODE_ATTRIBUTES"}{CODE};
65	*{(caller)[0]."::MODIFY_CODE_ATTRIBUTES"} = sub {	74	*{(caller)[0]."::MODIFY_CODE_ATTRIBUTES"} = sub {
66	my ($package, $ref) = (shift, shift);	75	my ($package, $ref) = (shift, shift);
67	my @attrs;	76	my @attrs;
…		…
105	C<Coro::current> function instead.	114	C<Coro::current> function instead.
106		115
107	=cut	116	=cut
108		117
109	# maybe some other module used Coro::Specific before...	118	# maybe some other module used Coro::Specific before...
110	if ($current) {
111	$main->{specific} = $current->{specific};	119	$main->{specific} = $current->{specific}
112	}	120	if $current;
113		121
114	$current = $main;	122	_set_current $main;
115		123
116	sub current() { $current }	124	sub current() { $current }
117		125
118	=item $idle	126	=item $idle
119		127
…		…
129	handlers), then it must be prepared to be called recursively.	137	handlers), then it must be prepared to be called recursively.
130		138
131	=cut	139	=cut
132		140
133	$idle = sub {	141	$idle = sub {
134	print STDERR "FATAL: deadlock detected\n";	142	require Carp;
135	exit (51);	143	Carp::croak ("FATAL: deadlock detected");
136	};	144	};
		145
		146	sub _cancel {
		147	my ($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	}
137		157
138	# this coroutine is necessary because a coroutine	158	# this coroutine is necessary because a coroutine
139	# cannot destroy itself.	159	# cannot destroy itself.
140	my @destroy;	160	my @destroy;
		161	my $manager;
		162
141	my $manager; $manager = new Coro sub {	163	$manager = new Coro sub {
142	while () {	164	while () {
143	# by overwriting the state object with the manager we destroy it	165	(shift @destroy)->_cancel
144	# while still being able to schedule this coroutine (in case it has
145	# been readied multiple times. this is harmless since the manager
146	# can be called as many times as neccessary and will always
147	# remove itself from the runqueue
148	while (@destroy) {	166	while @destroy;
149	my $coro = pop @destroy;
150	$coro->{status} \|\|= [];
151	$_->ready for @{delete $coro->{join} \|\| []};
152		167
153	# the next line destroys the coro state, but keeps the
154	# coroutine itself intact (we basically make it a zombie
155	# coroutine that always runs the manager thread, so it's possible
156	# to transfer() to this coroutine).
157	$coro->_clone_state_from ($manager);
158	}
159	&schedule;	168	&schedule;
160	}	169	}
161	};	170	};
		171
		172	$manager->prio (PRIO_MAX);
162		173
163	# static methods. not really.	174	# static methods. not really.
164		175
165	=back	176	=back
166		177
…		…
187	} 1,2,3,4;	198	} 1,2,3,4;
188		199
189	=cut	200	=cut
190		201
191	sub async(&@) {	202	sub async(&@) {
192	my $pid = new Coro @_;	203	my $coro = new Coro @_;
193	$pid->ready;	204	$coro->ready;
194	$pid	205	$coro
		206	}
		207
		208	=item async_pool { ... } [@args...]
		209
		210	Similar to C<async>, but uses a coroutine pool, so you should not call
		211	terminate or join (although you are allowed to), and you get a coroutine
		212	that might have executed other code already (which can be good or bad :).
		213
		214	Also, the block is executed in an C<eval> context and a warning will be
		215	issued in case of an exception instead of terminating the program, as C<async> does.
		216
		217	The priority will be reset to C<0> after each job, otherwise the coroutine
		218	will be re-used "as-is".
		219
		220	The pool size is limited to 8 idle coroutines (this can be adjusted by
		221	changing $Coro::POOL_SIZE), and there can be as many non-idle coros as
		222	required.
		223
		224	If you are concerned about pooled coroutines growing a lot because a
		225	single C<async_pool> used a lot of stackspace you can e.g. C<async_pool {
		226	terminate }> once per second or so to slowly replenish the pool.
		227
		228	=cut
		229
		230	our $POOL_SIZE = 8;
		231	our @pool;
		232
		233	sub pool_handler {
		234	while () {
		235	my ($cb, @arg) = @{ delete $current->{_invoke} };
		236
		237	eval {
		238	$cb->(@arg);
		239	};
		240	warn $@ if $@;
		241
		242	last if @pool >= $POOL_SIZE;
		243	push @pool, $current;
		244
		245	$current->prio (0);
		246	schedule;
		247	}
		248	}
		249
		250	sub async_pool(&@) {
		251	# this is also inlined into the unlock_scheduler
		252	my $coro = (pop @pool or new Coro \&pool_handler);
		253
		254	$coro->{_invoke} = [@_];
		255	$coro->ready;
		256
		257	$coro
195	}	258	}
196		259
197	=item schedule	260	=item schedule
198		261
199	Calls the scheduler. Please note that the current coroutine will not be put	262	Calls the scheduler. Please note that the current coroutine will not be put
…		…
224		287
225	"Cede" to other coroutines. This function puts the current coroutine into the	288	"Cede" to other coroutines. This function puts the current coroutine into the
226	ready queue and calls C<schedule>, which has the effect of giving up the	289	ready queue and calls C<schedule>, which has the effect of giving up the
227	current "timeslice" to other coroutines of the same or higher priority.	290	current "timeslice" to other coroutines of the same or higher priority.
228		291
		292	=item Coro::cede_notself
		293
		294	Works like cede, but is not exported by default and will cede to any
		295	coroutine, regardless of priority, once.
		296
229	=item terminate [arg...]	297	=item terminate [arg...]
230		298
231	Terminates the current coroutine with the given status values (see L<cancel>).	299	Terminates the current coroutine with the given status values (see L<cancel>).
232		300
233	=cut	301	=cut
…		…
255		323
256	Calling C<exit> in a coroutine will not work correctly, so do not do that.	324	Calling C<exit> in a coroutine will not work correctly, so do not do that.
257		325
258	=cut	326	=cut
259		327
260	sub _new_coro {	328	sub _run_coro {
261	terminate &{+shift};	329	terminate &{+shift};
262	}	330	}
263		331
264	sub new {	332	sub new {
265	my $class = shift;	333	my $class = shift;
266		334
267	$class->SUPER::new (\&_new_coro, @_)	335	$class->SUPER::new (\&_run_coro, @_)
268	}	336	}
269		337
270	=item $success = $coroutine->ready	338	=item $success = $coroutine->ready
271		339
272	Put the given coroutine into the ready queue (according to it's priority)	340	Put the given coroutine into the ready queue (according to it's priority)
…		…
278	Return wether the coroutine is currently the ready queue or not,	346	Return wether the coroutine is currently the ready queue or not,
279		347
280	=item $coroutine->cancel (arg...)	348	=item $coroutine->cancel (arg...)
281		349
282	Terminates the given coroutine and makes it return the given arguments as	350	Terminates the given coroutine and makes it return the given arguments as
283	status (default: the empty list).	351	status (default: the empty list). Never returns if the coroutine is the
		352	current coroutine.
284		353
285	=cut	354	=cut
286		355
287	sub cancel {	356	sub cancel {
288	my $self = shift;	357	my $self = shift;
289	$self->{status} = [@_];	358	$self->{status} = [@_];
		359
		360	if ($current == $self) {
290	push @destroy, $self;	361	push @destroy, $self;
291	$manager->ready;	362	$manager->ready;
292	&schedule if $current == $self;	363	&schedule while 1;
		364	} else {
		365	$self->_cancel;
		366	}
293	}	367	}
294		368
295	=item $coroutine->join	369	=item $coroutine->join
296		370
297	Wait until the coroutine terminates and return any values given to the	371	Wait until the coroutine terminates and return any values given to the
…		…
300		374
301	=cut	375	=cut
302		376
303	sub join {	377	sub join {
304	my $self = shift;	378	my $self = shift;
		379
305	unless ($self->{status}) {	380	unless ($self->{status}) {
306	push @{$self->{join}}, $current;	381	my $current = $current;
307	&schedule;	382
		383	push @{$self->{destroy_cb}}, sub {
		384	$current->ready;
		385	undef $current;
		386	};
		387
		388	&schedule while $current;
308	}	389	}
		390
309	wantarray ? @{$self->{status}} : $self->{status}[0];	391	wantarray ? @{$self->{status}} : $self->{status}[0];
		392	}
		393
		394	=item $coroutine->on_destroy (\&cb)
		395
		396	Registers a callback that is called when this coroutine gets destroyed,
		397	but before it is joined. The callback gets passed the terminate arguments,
		398	if any.
		399
		400	=cut
		401
		402	sub on_destroy {
		403	my ($self, $cb) = @_;
		404
		405	push @{ $self->{destroy_cb} }, $cb;
310	}	406	}
311		407
312	=item $oldprio = $coroutine->prio ($newprio)	408	=item $oldprio = $coroutine->prio ($newprio)
313		409
314	Sets (or gets, if the argument is missing) the priority of the	410	Sets (or gets, if the argument is missing) the priority of the
…		…
349	$old;	445	$old;
350	}	446	}
351		447
352	=back	448	=back
353		449
354	=head2 UTILITY FUNCTIONS	450	=head2 GLOBAL FUNCTIONS
355		451
356	=over 4	452	=over 4
		453
		454	=item Coro::nready
		455
		456	Returns the number of coroutines that are currently in the ready state,
		457	i.e. that can be swicthed to. The value C<0> means that the only runnable
		458	coroutine is the currently running one, so C<cede> would have no effect,
		459	and C<schedule> would cause a deadlock unless there is an idle handler
		460	that wakes up some coroutines.
		461
		462	=item my $guard = Coro::guard { ... }
		463
		464	This creates and returns a guard object. Nothing happens until the objetc
		465	gets destroyed, in which case the codeblock given as argument will be
		466	executed. This is useful to free locks or other resources in case of a
		467	runtime error or when the coroutine gets canceled, as in both cases the
		468	guard block will be executed. The guard object supports only one method,
		469	C<< ->cancel >>, which will keep the codeblock from being executed.
		470
		471	Example: set some flag and clear it again when the coroutine gets canceled
		472	or the function returns:
		473
		474	sub do_something {
		475	my $guard = Coro::guard { $busy = 0 };
		476	$busy = 1;
		477
		478	# do something that requires $busy to be true
		479	}
		480
		481	=cut
		482
		483	sub guard(&) {
		484	bless \(my $cb = $_[0]), "Coro::guard"
		485	}
		486
		487	sub Coro::guard::cancel {
		488	${$_[0]} = sub { };
		489	}
		490
		491	sub Coro::guard::DESTROY {
		492	${$_[0]}->();
		493	}
		494
357		495
358	=item unblock_sub { ... }	496	=item unblock_sub { ... }
359		497
360	This utility function takes a BLOCK or code reference and "unblocks" it,	498	This utility function takes a BLOCK or code reference and "unblocks" it,
361	returning the new coderef. This means that the new coderef will return	499	returning the new coderef. This means that the new coderef will return
…		…
375	In short: simply use C<unblock_sub { ... }> instead of C<sub { ... }> when	513	In short: simply use C<unblock_sub { ... }> instead of C<sub { ... }> when
376	creating event callbacks that want to block.	514	creating event callbacks that want to block.
377		515
378	=cut	516	=cut
379		517
380	our @unblock_pool;
381	our @unblock_queue;	518	our @unblock_queue;
382	our $UNBLOCK_POOL_SIZE = 2;
383		519
384	sub unblock_handler_ {	520	# we create a special coro because we want to cede,
385	while () {	521	# to reduce pressure on the coro pool (because most callbacks
386	my ($cb, @arg) = @{ delete $Coro::current->{arg} };	522	# return immediately and can be reused) and because we cannot cede
387	$cb->(@arg);	523	# inside an event callback.
388
389	last if @unblock_pool >= $UNBLOCK_POOL_SIZE;
390	push @unblock_pool, $Coro::current;
391	schedule;
392	}
393	}
394
395	our $unblock_scheduler = async {	524	our $unblock_scheduler = async {
396	while () {	525	while () {
397	while (my $cb = pop @unblock_queue) {	526	while (my $cb = pop @unblock_queue) {
		527	# this is an inlined copy of async_pool
398	my $handler = (pop @unblock_pool or new Coro \&unblock_handler_);	528	my $coro = (pop @pool or new Coro \&pool_handler);
399	$handler->{arg} = $cb;	529
		530	$coro->{_invoke} = $cb;
400	$handler->ready;	531	$coro->ready;
401	cede;	532	cede; # for short-lived callbacks, this reduces pressure on the coro pool
402	}	533	}
403		534	schedule; # sleep well
404	schedule;
405	}	535	}
406	};	536	};
407		537
408	sub unblock_sub(&) {	538	sub unblock_sub(&) {
409	my $cb = shift;	539	my $cb = shift;
410		540
411	sub {	541	sub {
412	push @unblock_queue, [$cb, @_];	542	unshift @unblock_queue, [$cb, @_];
413	$unblock_scheduler->ready;	543	$unblock_scheduler->ready;
414	}	544	}
415	}	545	}
416		546
417	=back	547	=back

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Comparing Coro/Coro.pm (file contents): Revision 1.92 by root, Fri Dec 1 03:47:55 2006 UTC vs. Revision 1.105 by root, Fri Jan 5 16:55:01 2007 UTC

Diff Legend

Comparing Coro/Coro.pm (file contents):
Revision 1.92 by root, Fri Dec 1 03:47:55 2006 UTC vs.
Revision 1.105 by root, Fri Jan 5 16:55:01 2007 UTC