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

Comparing Coro/Coro.pm (file contents):
Revision 1.96 by root, Mon Dec 4 03:48:16 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 = '3.01';	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
…		…
132	$idle = sub {	141	$idle = sub {
133	require Carp;	142	require Carp;
134	Carp::croak ("FATAL: deadlock detected");	143	Carp::croak ("FATAL: deadlock detected");
135	};	144	};
136		145
		146	sub _cancel {
		147	my ($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
137	# this coroutine is necessary because a coroutine	158	# this coroutine is necessary because a coroutine
138	# cannot destroy itself.	159	# cannot destroy itself.
139	my @destroy;	160	my @destroy;
		161	my $manager;
		162
140	my $manager; $manager = new Coro sub {	163	$manager = new Coro sub {
141	while () {	164	while () {
142	# by overwriting the state object with the manager we destroy it	165	(shift @destroy)->_cancel
143	# while still being able to schedule this coroutine (in case it has
144	# been readied multiple times. this is harmless since the manager
145	# can be called as many times as neccessary and will always
146	# remove itself from the runqueue
147	while (@destroy) {	166	while @destroy;
148	my $coro = pop @destroy;
149	$coro->{status} \|\|= [];
150	$_->ready for @{delete $coro->{join} \|\| []};
151		167
152	# the next line destroys the coro state, but keeps the
153	# coroutine itself intact (we basically make it a zombie
154	# coroutine that always runs the manager thread, so it's possible
155	# to transfer() to this coroutine).
156	$coro->_clone_state_from ($manager);
157	}
158	&schedule;	168	&schedule;
159	}	169	}
160	};	170	};
		171
		172	$manager->prio (PRIO_MAX);
161		173
162	# static methods. not really.	174	# static methods. not really.
163		175
164	=back	176	=back
165		177
…		…
186	} 1,2,3,4;	198	} 1,2,3,4;
187		199
188	=cut	200	=cut
189		201
190	sub async(&@) {	202	sub async(&@) {
191	my $pid = new Coro @_;	203	my $coro = new Coro @_;
192	$pid->ready;	204	$coro->ready;
193	$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
194	}	258	}
195		259
196	=item schedule	260	=item schedule
197		261
198	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
…		…
223		287
224	"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
225	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
226	current "timeslice" to other coroutines of the same or higher priority.	290	current "timeslice" to other coroutines of the same or higher priority.
227		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
228	=item terminate [arg...]	297	=item terminate [arg...]
229		298
230	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>).
231		300
232	=cut	301	=cut
…		…
277	Return wether the coroutine is currently the ready queue or not,	346	Return wether the coroutine is currently the ready queue or not,
278		347
279	=item $coroutine->cancel (arg...)	348	=item $coroutine->cancel (arg...)
280		349
281	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
282	status (default: the empty list).	351	status (default: the empty list). Never returns if the coroutine is the
		352	current coroutine.
283		353
284	=cut	354	=cut
285		355
286	sub cancel {	356	sub cancel {
287	my $self = shift;	357	my $self = shift;
288	$self->{status} = [@_];	358	$self->{status} = [@_];
		359
		360	if ($current == $self) {
289	push @destroy, $self;	361	push @destroy, $self;
290	$manager->ready;	362	$manager->ready;
291	&schedule if $current == $self;	363	&schedule while 1;
		364	} else {
		365	$self->_cancel;
		366	}
292	}	367	}
293		368
294	=item $coroutine->join	369	=item $coroutine->join
295		370
296	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
…		…
299		374
300	=cut	375	=cut
301		376
302	sub join {	377	sub join {
303	my $self = shift;	378	my $self = shift;
		379
304	unless ($self->{status}) {	380	unless ($self->{status}) {
305	push @{$self->{join}}, $current;	381	my $current = $current;
306	&schedule;	382
		383	push @{$self->{destroy_cb}}, sub {
		384	$current->ready;
		385	undef $current;
		386	};
		387
		388	&schedule while $current;
307	}	389	}
		390
308	wantarray ? @{$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;
309	}	406	}
310		407
311	=item $oldprio = $coroutine->prio ($newprio)	408	=item $oldprio = $coroutine->prio ($newprio)
312		409
313	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
…		…
348	$old;	445	$old;
349	}	446	}
350		447
351	=back	448	=back
352		449
353	=head2 UTILITY FUNCTIONS	450	=head2 GLOBAL FUNCTIONS
354		451
355	=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
356		495
357	=item unblock_sub { ... }	496	=item unblock_sub { ... }
358		497
359	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,
360	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
…		…
374	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
375	creating event callbacks that want to block.	514	creating event callbacks that want to block.
376		515
377	=cut	516	=cut
378		517
379	our @unblock_pool;
380	our @unblock_queue;	518	our @unblock_queue;
381	our $UNBLOCK_POOL_SIZE = 2;
382		519
383	sub unblock_handler_ {	520	# we create a special coro because we want to cede,
384	while () {	521	# to reduce pressure on the coro pool (because most callbacks
385	my ($cb, @arg) = @{ delete $Coro::current->{arg} };	522	# return immediately and can be reused) and because we cannot cede
386	$cb->(@arg);	523	# inside an event callback.
387
388	last if @unblock_pool >= $UNBLOCK_POOL_SIZE;
389	push @unblock_pool, $Coro::current;
390	schedule;
391	}
392	}
393
394	our $unblock_scheduler = async {	524	our $unblock_scheduler = async {
395	while () {	525	while () {
396	while (my $cb = pop @unblock_queue) {	526	while (my $cb = pop @unblock_queue) {
		527	# this is an inlined copy of async_pool
397	my $handler = (pop @unblock_pool or new Coro \&unblock_handler_);	528	my $coro = (pop @pool or new Coro \&pool_handler);
398	$handler->{arg} = $cb;	529
		530	$coro->{_invoke} = $cb;
399	$handler->ready;	531	$coro->ready;
400	cede;	532	cede; # for short-lived callbacks, this reduces pressure on the coro pool
401	}	533	}
402		534	schedule; # sleep well
403	schedule;
404	}	535	}
405	};	536	};
406		537
407	sub unblock_sub(&) {	538	sub unblock_sub(&) {
408	my $cb = shift;	539	my $cb = shift;
409		540
410	sub {	541	sub {
411	push @unblock_queue, [$cb, @_];	542	unshift @unblock_queue, [$cb, @_];
412	$unblock_scheduler->ready;	543	$unblock_scheduler->ready;
413	}	544	}
414	}	545	}
415		546
416	=back	547	=back

Diff Legend

-–
+Removed lines
-+
+Added lines
-<
+Changed lines
->
+Changed lines

Comparing Coro/Coro.pm (file contents): Revision 1.96 by root, Mon Dec 4 03:48:16 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 1.96 by root, Mon Dec 4 03:48:16 2006 UTC vs.
Revision 1.105 by root, Fri Jan 5 16:55:01 2007 UTC