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

Comparing Coro/Coro.pm (file contents):
Revision 1.95 by root, Sun Dec 3 22:50:06 2006 UTC vs.
Revision 1.107 by root, Fri Jan 5 18:25:51 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
…		…
128	handlers), then it must be prepared to be called recursively.	137	handlers), then it must be prepared to be called recursively.
129		138
130	=cut	139	=cut
131		140
132	$idle = sub {	141	$idle = sub {
133	print STDERR "FATAL: deadlock detected\n";	142	require Carp;
134	exit (51);	143	Carp::croak ("FATAL: deadlock detected");
135	};	144	};
		145
		146	sub _cancel {
		147	my ($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	}
136		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	Returns true if at least one coroutine switch has happened.
		293
		294	=item Coro::cede_notself
		295
		296	Works like cede, but is not exported by default and will cede to any
		297	coroutine, regardless of priority, once.
		298
		299	Returns true if at least one coroutine switch has happened.
		300
228	=item terminate [arg...]	301	=item terminate [arg...]
229		302
230	Terminates the current coroutine with the given status values (see L<cancel>).	303	Terminates the current coroutine with the given status values (see L<cancel>).
231		304
232	=cut	305	=cut
…		…
277	Return wether the coroutine is currently the ready queue or not,	350	Return wether the coroutine is currently the ready queue or not,
278		351
279	=item $coroutine->cancel (arg...)	352	=item $coroutine->cancel (arg...)
280		353
281	Terminates the given coroutine and makes it return the given arguments as	354	Terminates the given coroutine and makes it return the given arguments as
282	status (default: the empty list).	355	status (default: the empty list). Never returns if the coroutine is the
		356	current coroutine.
283		357
284	=cut	358	=cut
285		359
286	sub cancel {	360	sub cancel {
287	my $self = shift;	361	my $self = shift;
288	$self->{status} = [@_];	362	$self->{status} = [@_];
		363
		364	if ($current == $self) {
289	push @destroy, $self;	365	push @destroy, $self;
290	$manager->ready;	366	$manager->ready;
291	&schedule if $current == $self;	367	&schedule while 1;
		368	} else {
		369	$self->_cancel;
		370	}
292	}	371	}
293		372
294	=item $coroutine->join	373	=item $coroutine->join
295		374
296	Wait until the coroutine terminates and return any values given to the	375	Wait until the coroutine terminates and return any values given to the
…		…
299		378
300	=cut	379	=cut
301		380
302	sub join {	381	sub join {
303	my $self = shift;	382	my $self = shift;
		383
304	unless ($self->{status}) {	384	unless ($self->{status}) {
305	push @{$self->{join}}, $current;	385	my $current = $current;
306	&schedule;	386
		387	push @{$self->{destroy_cb}}, sub {
		388	$current->ready;
		389	undef $current;
		390	};
		391
		392	&schedule while $current;
307	}	393	}
		394
308	wantarray ? @{$self->{status}} : $self->{status}[0];	395	wantarray ? @{$self->{status}} : $self->{status}[0];
		396	}
		397
		398	=item $coroutine->on_destroy (\&cb)
		399
		400	Registers a callback that is called when this coroutine gets destroyed,
		401	but before it is joined. The callback gets passed the terminate arguments,
		402	if any.
		403
		404	=cut
		405
		406	sub on_destroy {
		407	my ($self, $cb) = @_;
		408
		409	push @{ $self->{destroy_cb} }, $cb;
309	}	410	}
310		411
311	=item $oldprio = $coroutine->prio ($newprio)	412	=item $oldprio = $coroutine->prio ($newprio)
312		413
313	Sets (or gets, if the argument is missing) the priority of the	414	Sets (or gets, if the argument is missing) the priority of the
…		…
348	$old;	449	$old;
349	}	450	}
350		451
351	=back	452	=back
352		453
353	=head2 UTILITY FUNCTIONS	454	=head2 GLOBAL FUNCTIONS
354		455
355	=over 4	456	=over 4
		457
		458	=item Coro::nready
		459
		460	Returns the number of coroutines that are currently in the ready state,
		461	i.e. that can be swicthed to. The value C<0> means that the only runnable
		462	coroutine is the currently running one, so C<cede> would have no effect,
		463	and C<schedule> would cause a deadlock unless there is an idle handler
		464	that wakes up some coroutines.
		465
		466	=item my $guard = Coro::guard { ... }
		467
		468	This creates and returns a guard object. Nothing happens until the objetc
		469	gets destroyed, in which case the codeblock given as argument will be
		470	executed. This is useful to free locks or other resources in case of a
		471	runtime error or when the coroutine gets canceled, as in both cases the
		472	guard block will be executed. The guard object supports only one method,
		473	C<< ->cancel >>, which will keep the codeblock from being executed.
		474
		475	Example: set some flag and clear it again when the coroutine gets canceled
		476	or the function returns:
		477
		478	sub do_something {
		479	my $guard = Coro::guard { $busy = 0 };
		480	$busy = 1;
		481
		482	# do something that requires $busy to be true
		483	}
		484
		485	=cut
		486
		487	sub guard(&) {
		488	bless \(my $cb = $_[0]), "Coro::guard"
		489	}
		490
		491	sub Coro::guard::cancel {
		492	${$_[0]} = sub { };
		493	}
		494
		495	sub Coro::guard::DESTROY {
		496	${$_[0]}->();
		497	}
		498
356		499
357	=item unblock_sub { ... }	500	=item unblock_sub { ... }
358		501
359	This utility function takes a BLOCK or code reference and "unblocks" it,	502	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	503	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	517	In short: simply use C<unblock_sub { ... }> instead of C<sub { ... }> when
375	creating event callbacks that want to block.	518	creating event callbacks that want to block.
376		519
377	=cut	520	=cut
378		521
379	our @unblock_pool;
380	our @unblock_queue;	522	our @unblock_queue;
381	our $UNBLOCK_POOL_SIZE = 2;
382		523
383	sub unblock_handler_ {	524	# we create a special coro because we want to cede,
384	while () {	525	# to reduce pressure on the coro pool (because most callbacks
385	my ($cb, @arg) = @{ delete $Coro::current->{arg} };	526	# return immediately and can be reused) and because we cannot cede
386	$cb->(@arg);	527	# 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 {	528	our $unblock_scheduler = async {
395	while () {	529	while () {
396	while (my $cb = pop @unblock_queue) {	530	while (my $cb = pop @unblock_queue) {
		531	# this is an inlined copy of async_pool
397	my $handler = (pop @unblock_pool or new Coro \&unblock_handler_);	532	my $coro = (pop @pool or new Coro \&pool_handler);
398	$handler->{arg} = $cb;	533
		534	$coro->{_invoke} = $cb;
399	$handler->ready;	535	$coro->ready;
400	cede;	536	cede; # for short-lived callbacks, this reduces pressure on the coro pool
401	}	537	}
402		538	schedule; # sleep well
403	schedule;
404	}	539	}
405	};	540	};
406		541
407	sub unblock_sub(&) {	542	sub unblock_sub(&) {
408	my $cb = shift;	543	my $cb = shift;
409		544
410	sub {	545	sub {
411	push @unblock_queue, [$cb, @_];	546	unshift @unblock_queue, [$cb, @_];
412	$unblock_scheduler->ready;	547	$unblock_scheduler->ready;
413	}	548	}
414	}	549	}
415		550
416	=back	551	=back

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Comparing Coro/Coro.pm (file contents): Revision 1.95 by root, Sun Dec 3 22:50:06 2006 UTC vs. Revision 1.107 by root, Fri Jan 5 18:25:51 2007 UTC

Diff Legend

Comparing Coro/Coro.pm (file contents):
Revision 1.95 by root, Sun Dec 3 22:50:06 2006 UTC vs.
Revision 1.107 by root, Fri Jan 5 18:25:51 2007 UTC