[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 1.108 by root, Fri Jan 5 20:00:49 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
		216	C<async> does. As the coroutine is being reused, stuff like C<on_destroy>
		217	will not work in the expected way, unless you call terminate or cancel,
		218	which somehow defeats the purpose of pooling.
		219
		220	The priority will be reset to C<0> after each job, otherwise the coroutine
		221	will be re-used "as-is".
		222
		223	The pool size is limited to 8 idle coroutines (this can be adjusted by
		224	changing $Coro::POOL_SIZE), and there can be as many non-idle coros as
		225	required.
		226
		227	If you are concerned about pooled coroutines growing a lot because a
		228	single C<async_pool> used a lot of stackspace you can e.g. C<async_pool {
		229	terminate }> once per second or so to slowly replenish the pool.
		230
		231	=cut
		232
		233	our $POOL_SIZE = 8;
		234	our @pool;
		235
		236	sub pool_handler {
		237	while () {
		238	my ($cb, @arg) = @{ delete $current->{_invoke} };
		239
		240	eval {
		241	$cb->(@arg);
		242	};
		243	warn $@ if $@;
		244
		245	last if @pool >= $POOL_SIZE;
		246	push @pool, $current;
		247
		248	$current->prio (0);
		249	schedule;
		250	}
		251	}
		252
		253	sub async_pool(&@) {
		254	# this is also inlined into the unlock_scheduler
		255	my $coro = (pop @pool or new Coro \&pool_handler);
		256
		257	$coro->{_invoke} = [@_];
		258	$coro->ready;
		259
		260	$coro
195	}	261	}
196		262
197	=item schedule	263	=item schedule
198		264
199	Calls the scheduler. Please note that the current coroutine will not be put	265	Calls the scheduler. Please note that the current coroutine will not be put
…		…
224		290
225	"Cede" to other coroutines. This function puts the current coroutine into the	291	"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	292	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.	293	current "timeslice" to other coroutines of the same or higher priority.
228		294
		295	Returns true if at least one coroutine switch has happened.
		296
		297	=item Coro::cede_notself
		298
		299	Works like cede, but is not exported by default and will cede to any
		300	coroutine, regardless of priority, once.
		301
		302	Returns true if at least one coroutine switch has happened.
		303
229	=item terminate [arg...]	304	=item terminate [arg...]
230		305
231	Terminates the current coroutine with the given status values (see L<cancel>).	306	Terminates the current coroutine with the given status values (see L<cancel>).
232		307
233	=cut	308	=cut
…		…
255		330
256	Calling C<exit> in a coroutine will not work correctly, so do not do that.	331	Calling C<exit> in a coroutine will not work correctly, so do not do that.
257		332
258	=cut	333	=cut
259		334
260	sub _new_coro {	335	sub _run_coro {
261	terminate &{+shift};	336	terminate &{+shift};
262	}	337	}
263		338
264	sub new {	339	sub new {
265	my $class = shift;	340	my $class = shift;
266		341
267	$class->SUPER::new (\&_new_coro, @_)	342	$class->SUPER::new (\&_run_coro, @_)
268	}	343	}
269		344
270	=item $success = $coroutine->ready	345	=item $success = $coroutine->ready
271		346
272	Put the given coroutine into the ready queue (according to it's priority)	347	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,	353	Return wether the coroutine is currently the ready queue or not,
279		354
280	=item $coroutine->cancel (arg...)	355	=item $coroutine->cancel (arg...)
281		356
282	Terminates the given coroutine and makes it return the given arguments as	357	Terminates the given coroutine and makes it return the given arguments as
283	status (default: the empty list).	358	status (default: the empty list). Never returns if the coroutine is the
		359	current coroutine.
284		360
285	=cut	361	=cut
286		362
287	sub cancel {	363	sub cancel {
288	my $self = shift;	364	my $self = shift;
289	$self->{status} = [@_];	365	$self->{status} = [@_];
		366
		367	if ($current == $self) {
290	push @destroy, $self;	368	push @destroy, $self;
291	$manager->ready;	369	$manager->ready;
292	&schedule if $current == $self;	370	&schedule while 1;
		371	} else {
		372	$self->_cancel;
		373	}
293	}	374	}
294		375
295	=item $coroutine->join	376	=item $coroutine->join
296		377
297	Wait until the coroutine terminates and return any values given to the	378	Wait until the coroutine terminates and return any values given to the
…		…
300		381
301	=cut	382	=cut
302		383
303	sub join {	384	sub join {
304	my $self = shift;	385	my $self = shift;
		386
305	unless ($self->{status}) {	387	unless ($self->{status}) {
306	push @{$self->{join}}, $current;	388	my $current = $current;
307	&schedule;	389
		390	push @{$self->{destroy_cb}}, sub {
		391	$current->ready;
		392	undef $current;
		393	};
		394
		395	&schedule while $current;
308	}	396	}
		397
309	wantarray ? @{$self->{status}} : $self->{status}[0];	398	wantarray ? @{$self->{status}} : $self->{status}[0];
		399	}
		400
		401	=item $coroutine->on_destroy (\&cb)
		402
		403	Registers a callback that is called when this coroutine gets destroyed,
		404	but before it is joined. The callback gets passed the terminate arguments,
		405	if any.
		406
		407	=cut
		408
		409	sub on_destroy {
		410	my ($self, $cb) = @_;
		411
		412	push @{ $self->{destroy_cb} }, $cb;
310	}	413	}
311		414
312	=item $oldprio = $coroutine->prio ($newprio)	415	=item $oldprio = $coroutine->prio ($newprio)
313		416
314	Sets (or gets, if the argument is missing) the priority of the	417	Sets (or gets, if the argument is missing) the priority of the
…		…
349	$old;	452	$old;
350	}	453	}
351		454
352	=back	455	=back
353		456
354	=head2 UTILITY FUNCTIONS	457	=head2 GLOBAL FUNCTIONS
355		458
356	=over 4	459	=over 4
		460
		461	=item Coro::nready
		462
		463	Returns the number of coroutines that are currently in the ready state,
		464	i.e. that can be swicthed to. The value C<0> means that the only runnable
		465	coroutine is the currently running one, so C<cede> would have no effect,
		466	and C<schedule> would cause a deadlock unless there is an idle handler
		467	that wakes up some coroutines.
		468
		469	=item my $guard = Coro::guard { ... }
		470
		471	This creates and returns a guard object. Nothing happens until the objetc
		472	gets destroyed, in which case the codeblock given as argument will be
		473	executed. This is useful to free locks or other resources in case of a
		474	runtime error or when the coroutine gets canceled, as in both cases the
		475	guard block will be executed. The guard object supports only one method,
		476	C<< ->cancel >>, which will keep the codeblock from being executed.
		477
		478	Example: set some flag and clear it again when the coroutine gets canceled
		479	or the function returns:
		480
		481	sub do_something {
		482	my $guard = Coro::guard { $busy = 0 };
		483	$busy = 1;
		484
		485	# do something that requires $busy to be true
		486	}
		487
		488	=cut
		489
		490	sub guard(&) {
		491	bless \(my $cb = $_[0]), "Coro::guard"
		492	}
		493
		494	sub Coro::guard::cancel {
		495	${$_[0]} = sub { };
		496	}
		497
		498	sub Coro::guard::DESTROY {
		499	${$_[0]}->();
		500	}
		501
357		502
358	=item unblock_sub { ... }	503	=item unblock_sub { ... }
359		504
360	This utility function takes a BLOCK or code reference and "unblocks" it,	505	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	506	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	520	In short: simply use C<unblock_sub { ... }> instead of C<sub { ... }> when
376	creating event callbacks that want to block.	521	creating event callbacks that want to block.
377		522
378	=cut	523	=cut
379		524
380	our @unblock_pool;
381	our @unblock_queue;	525	our @unblock_queue;
382	our $UNBLOCK_POOL_SIZE = 2;
383		526
384	sub unblock_handler_ {	527	# we create a special coro because we want to cede,
385	while () {	528	# to reduce pressure on the coro pool (because most callbacks
386	my ($cb, @arg) = @{ delete $Coro::current->{arg} };	529	# return immediately and can be reused) and because we cannot cede
387	$cb->(@arg);	530	# 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 {	531	our $unblock_scheduler = async {
396	while () {	532	while () {
397	while (my $cb = pop @unblock_queue) {	533	while (my $cb = pop @unblock_queue) {
		534	# this is an inlined copy of async_pool
398	my $handler = (pop @unblock_pool or new Coro \&unblock_handler_);	535	my $coro = (pop @pool or new Coro \&pool_handler);
399	$handler->{arg} = $cb;	536
		537	$coro->{_invoke} = $cb;
400	$handler->ready;	538	$coro->ready;
401	cede;	539	cede; # for short-lived callbacks, this reduces pressure on the coro pool
402	}	540	}
403		541	schedule; # sleep well
404	schedule;
405	}	542	}
406	};	543	};
407		544
408	sub unblock_sub(&) {	545	sub unblock_sub(&) {
409	my $cb = shift;	546	my $cb = shift;
410		547
411	sub {	548	sub {
412	push @unblock_queue, [$cb, @_];	549	unshift @unblock_queue, [$cb, @_];
413	$unblock_scheduler->ready;	550	$unblock_scheduler->ready;
414	}	551	}
415	}	552	}
416		553
417	=back	554	=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 1.108 by root, Fri Jan 5 20:00:49 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 1.108 by root, Fri Jan 5 20:00:49 2007 UTC