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

Comparing Coro/Coro.pm (file contents):
Revision 1.98 by root, Mon Dec 4 21:56:00 2006 UTC vs.
Revision 1.133 by root, Fri Sep 21 01:23:58 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 = '3.1';	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
		118	$main->{desc} = "[main::]";
117		119
118	# maybe some other module used Coro::Specific before...	120	# maybe some other module used Coro::Specific before...
119	$main->{specific} = $current->{specific}	121	$main->{specific} = $current->{specific}
120	if $current;	122	if $current;
121		123
…		…
141	$idle = sub {	143	$idle = sub {
142	require Carp;	144	require Carp;
143	Carp::croak ("FATAL: deadlock detected");	145	Carp::croak ("FATAL: deadlock detected");
144	};	146	};
145		147
		148	sub _cancel {
		149	my ($self) = @_;
		150
		151	# free coroutine data and mark as destructed
		152	$self->_destroy
		153	or return;
		154
		155	# call all destruction callbacks
		156	$_->(@{$self->{status}})
		157	for @{(delete $self->{destroy_cb}) \|\| []};
		158	}
		159
146	# this coroutine is necessary because a coroutine	160	# this coroutine is necessary because a coroutine
147	# cannot destroy itself.	161	# cannot destroy itself.
148	my @destroy;	162	my @destroy;
		163	my $manager;
		164
149	my $manager; $manager = new Coro sub {	165	$manager = new Coro sub {
150	while () {	166	while () {
151	# by overwriting the state object with the manager we destroy it	167	(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) {	168	while @destroy;
157	my $coro = pop @destroy;
158	$coro->{status} \|\|= [];
159	$_->ready for @{delete $coro->{join} \|\| []};
160		169
161	# the next line destroys the coro state, but keeps the
162	# coroutine itself intact (we basically make it a zombie
163	# coroutine that always runs the manager thread, so it's possible
164	# to transfer() to this coroutine).
165	$coro->_clone_state_from ($manager);
166	}
167	&schedule;	170	&schedule;
168	}	171	}
169	};	172	};
		173	$manager->desc ("[coro manager]");
		174	$manager->prio (PRIO_MAX);
170		175
171	# static methods. not really.	176	# static methods. not really.
172		177
173	=back	178	=back
174		179
…		…
182		187
183	Create a new asynchronous coroutine and return it's coroutine object	188	Create a new asynchronous coroutine and return it's coroutine object
184	(usually unused). When the sub returns the new coroutine is automatically	189	(usually unused). When the sub returns the new coroutine is automatically
185	terminated.	190	terminated.
186		191
187	Calling C<exit> in a coroutine will not work correctly, so do not do that.	192	Calling C<exit> in a coroutine will do the same as calling exit outside
188		193	the coroutine. Likewise, when the coroutine dies, the program will exit,
189	When the coroutine dies, the program will exit, just as in the main	194	just as it would in the main program.
190	program.
191		195
192	# create a new coroutine that just prints its arguments	196	# create a new coroutine that just prints its arguments
193	async {	197	async {
194	print "@_\n";	198	print "@_\n";
195	} 1,2,3,4;	199	} 1,2,3,4;
196		200
197	=cut	201	=cut
198		202
199	sub async(&@) {	203	sub async(&@) {
200	my $pid = new Coro @_;	204	my $coro = new Coro @_;
201	$pid->ready;	205	$coro->ready;
202	$pid	206	$coro
		207	}
		208
		209	=item async_pool { ... } [@args...]
		210
		211	Similar to C<async>, but uses a coroutine pool, so you should not call
		212	terminate or join (although you are allowed to), and you get a coroutine
		213	that might have executed other code already (which can be good or bad :).
		214
		215	Also, the block is executed in an C<eval> context and a warning will be
		216	issued in case of an exception instead of terminating the program, as
		217	C<async> does. As the coroutine is being reused, stuff like C<on_destroy>
		218	will not work in the expected way, unless you call terminate or cancel,
		219	which somehow defeats the purpose of pooling.
		220
		221	The priority will be reset to C<0> after each job, otherwise the coroutine
		222	will be re-used "as-is".
		223
		224	The pool size is limited to 8 idle coroutines (this can be adjusted by
		225	changing $Coro::POOL_SIZE), and there can be as many non-idle coros as
		226	required.
		227
		228	If you are concerned about pooled coroutines growing a lot because a
		229	single C<async_pool> used a lot of stackspace you can e.g. C<async_pool
		230	{ terminate }> once per second or so to slowly replenish the pool. In
		231	addition to that, when the stacks used by a handler grows larger than 16kb
		232	(adjustable with $Coro::MAX_POOL_RSS) it will also exit.
		233
		234	=cut
		235
		236	our $POOL_SIZE = 8;
		237	our $MAX_POOL_RSS = 16 * 1024;
		238	our @pool;
		239
		240	sub pool_handler {
		241	while () {
		242	$current->{desc} = "[async_pool]";
		243
		244	eval {
		245	my ($cb, @arg) = @{ delete $current->{_invoke} or return };
		246	$cb->(@arg);
		247	};
		248	warn $@ if $@;
		249
		250	last if @pool >= $POOL_SIZE \|\| $current->rss >= $MAX_POOL_RSS;
		251
		252	push @pool, $current;
		253	$current->{desc} = "[async_pool idle]";
		254	$current->save (Coro::State::SAVE_DEF);
		255	$current->prio (0);
		256	schedule;
		257	}
		258	}
		259
		260	sub async_pool(&@) {
		261	# this is also inlined into the unlock_scheduler
		262	my $coro = (pop @pool) \|\| new Coro \&pool_handler;;
		263
		264	$coro->{_invoke} = [@_];
		265	$coro->ready;
		266
		267	$coro
203	}	268	}
204		269
205	=item schedule	270	=item schedule
206		271
207	Calls the scheduler. Please note that the current coroutine will not be put	272	Calls the scheduler. Please note that the current coroutine will not be put
…		…
220	# wake up sleeping coroutine	285	# wake up sleeping coroutine
221	$current->ready;	286	$current->ready;
222	undef $current;	287	undef $current;
223	};	288	};
224		289
225	# call schedule until event occured.	290	# call schedule until event occurred.
226	# in case we are woken up for other reasons	291	# in case we are woken up for other reasons
227	# (current still defined), loop.	292	# (current still defined), loop.
228	Coro::schedule while $current;	293	Coro::schedule while $current;
229	}	294	}
230		295
231	=item cede	296	=item cede
232		297
233	"Cede" to other coroutines. This function puts the current coroutine into the	298	"Cede" to other coroutines. This function puts the current coroutine into the
234	ready queue and calls C<schedule>, which has the effect of giving up the	299	ready queue and calls C<schedule>, which has the effect of giving up the
235	current "timeslice" to other coroutines of the same or higher priority.	300	current "timeslice" to other coroutines of the same or higher priority.
		301
		302	Returns true if at least one coroutine switch has happened.
		303
		304	=item Coro::cede_notself
		305
		306	Works like cede, but is not exported by default and will cede to any
		307	coroutine, regardless of priority, once.
		308
		309	Returns true if at least one coroutine switch has happened.
236		310
237	=item terminate [arg...]	311	=item terminate [arg...]
238		312
239	Terminates the current coroutine with the given status values (see L<cancel>).	313	Terminates the current coroutine with the given status values (see L<cancel>).
240		314
…		…
259	Create a new coroutine and return it. When the sub returns the coroutine	333	Create a new coroutine and return it. When the sub returns the coroutine
260	automatically terminates as if C<terminate> with the returned values were	334	automatically terminates as if C<terminate> with the returned values were
261	called. To make the coroutine run you must first put it into the ready queue	335	called. To make the coroutine run you must first put it into the ready queue
262	by calling the ready method.	336	by calling the ready method.
263		337
264	Calling C<exit> in a coroutine will not work correctly, so do not do that.	338	See C<async> for additional discussion.
265		339
266	=cut	340	=cut
267		341
268	sub _run_coro {	342	sub _run_coro {
269	terminate &{+shift};	343	terminate &{+shift};
…		…
286	Return wether the coroutine is currently the ready queue or not,	360	Return wether the coroutine is currently the ready queue or not,
287		361
288	=item $coroutine->cancel (arg...)	362	=item $coroutine->cancel (arg...)
289		363
290	Terminates the given coroutine and makes it return the given arguments as	364	Terminates the given coroutine and makes it return the given arguments as
291	status (default: the empty list).	365	status (default: the empty list). Never returns if the coroutine is the
		366	current coroutine.
292		367
293	=cut	368	=cut
294		369
295	sub cancel {	370	sub cancel {
296	my $self = shift;	371	my $self = shift;
297	$self->{status} = [@_];	372	$self->{status} = [@_];
		373
		374	if ($current == $self) {
298	push @destroy, $self;	375	push @destroy, $self;
299	$manager->ready;	376	$manager->ready;
300	&schedule if $current == $self;	377	&schedule while 1;
		378	} else {
		379	$self->_cancel;
		380	}
301	}	381	}
302		382
303	=item $coroutine->join	383	=item $coroutine->join
304		384
305	Wait until the coroutine terminates and return any values given to the	385	Wait until the coroutine terminates and return any values given to the
…		…
308		388
309	=cut	389	=cut
310		390
311	sub join {	391	sub join {
312	my $self = shift;	392	my $self = shift;
		393
313	unless ($self->{status}) {	394	unless ($self->{status}) {
314	push @{$self->{join}}, $current;	395	my $current = $current;
315	&schedule;	396
		397	push @{$self->{destroy_cb}}, sub {
		398	$current->ready;
		399	undef $current;
		400	};
		401
		402	&schedule while $current;
316	}	403	}
		404
317	wantarray ? @{$self->{status}} : $self->{status}[0];	405	wantarray ? @{$self->{status}} : $self->{status}[0];
		406	}
		407
		408	=item $coroutine->on_destroy (\&cb)
		409
		410	Registers a callback that is called when this coroutine gets destroyed,
		411	but before it is joined. The callback gets passed the terminate arguments,
		412	if any.
		413
		414	=cut
		415
		416	sub on_destroy {
		417	my ($self, $cb) = @_;
		418
		419	push @{ $self->{destroy_cb} }, $cb;
318	}	420	}
319		421
320	=item $oldprio = $coroutine->prio ($newprio)	422	=item $oldprio = $coroutine->prio ($newprio)
321		423
322	Sets (or gets, if the argument is missing) the priority of the	424	Sets (or gets, if the argument is missing) the priority of the
…		…
364	=over 4	466	=over 4
365		467
366	=item Coro::nready	468	=item Coro::nready
367		469
368	Returns the number of coroutines that are currently in the ready state,	470	Returns the number of coroutines that are currently in the ready state,
369	i.e. that can be swicthed to. The value C<0> means that the only runnable	471	i.e. that can be switched to. The value C<0> means that the only runnable
370	coroutine is the currently running one, so C<cede> would have no effect,	472	coroutine is the currently running one, so C<cede> would have no effect,
371	and C<schedule> would cause a deadlock unless there is an idle handler	473	and C<schedule> would cause a deadlock unless there is an idle handler
372	that wakes up some coroutines.	474	that wakes up some coroutines.
		475
		476	=item my $guard = Coro::guard { ... }
		477
		478	This creates and returns a guard object. Nothing happens until the object
		479	gets destroyed, in which case the codeblock given as argument will be
		480	executed. This is useful to free locks or other resources in case of a
		481	runtime error or when the coroutine gets canceled, as in both cases the
		482	guard block will be executed. The guard object supports only one method,
		483	C<< ->cancel >>, which will keep the codeblock from being executed.
		484
		485	Example: set some flag and clear it again when the coroutine gets canceled
		486	or the function returns:
		487
		488	sub do_something {
		489	my $guard = Coro::guard { $busy = 0 };
		490	$busy = 1;
		491
		492	# do something that requires $busy to be true
		493	}
		494
		495	=cut
		496
		497	sub guard(&) {
		498	bless \(my $cb = $_[0]), "Coro::guard"
		499	}
		500
		501	sub Coro::guard::cancel {
		502	${$_[0]} = sub { };
		503	}
		504
		505	sub Coro::guard::DESTROY {
		506	${$_[0]}->();
		507	}
		508
373		509
374	=item unblock_sub { ... }	510	=item unblock_sub { ... }
375		511
376	This utility function takes a BLOCK or code reference and "unblocks" it,	512	This utility function takes a BLOCK or code reference and "unblocks" it,
377	returning the new coderef. This means that the new coderef will return	513	returning the new coderef. This means that the new coderef will return
378	immediately without blocking, returning nothing, while the original code	514	immediately without blocking, returning nothing, while the original code
379	ref will be called (with parameters) from within its own coroutine.	515	ref will be called (with parameters) from within its own coroutine.
380		516
381	The reason this fucntion exists is that many event libraries (such as the	517	The reason this function exists is that many event libraries (such as the
382	venerable L<Event\|Event> module) are not coroutine-safe (a weaker form	518	venerable L<Event\|Event> module) are not coroutine-safe (a weaker form
383	of thread-safety). This means you must not block within event callbacks,	519	of thread-safety). This means you must not block within event callbacks,
384	otherwise you might suffer from crashes or worse.	520	otherwise you might suffer from crashes or worse.
385		521
386	This function allows your callbacks to block by executing them in another	522	This function allows your callbacks to block by executing them in another
…		…
391	In short: simply use C<unblock_sub { ... }> instead of C<sub { ... }> when	527	In short: simply use C<unblock_sub { ... }> instead of C<sub { ... }> when
392	creating event callbacks that want to block.	528	creating event callbacks that want to block.
393		529
394	=cut	530	=cut
395		531
396	our @unblock_pool;
397	our @unblock_queue;	532	our @unblock_queue;
398	our $UNBLOCK_POOL_SIZE = 2;
399		533
400	sub unblock_handler_ {	534	# we create a special coro because we want to cede,
401	while () {	535	# to reduce pressure on the coro pool (because most callbacks
402	my ($cb, @arg) = @{ delete $Coro::current->{arg} };	536	# return immediately and can be reused) and because we cannot cede
403	$cb->(@arg);	537	# inside an event callback.
404
405	last if @unblock_pool >= $UNBLOCK_POOL_SIZE;
406	push @unblock_pool, $Coro::current;
407	schedule;
408	}
409	}
410
411	our $unblock_scheduler = async {	538	our $unblock_scheduler = new Coro sub {
412	while () {	539	while () {
413	while (my $cb = pop @unblock_queue) {	540	while (my $cb = pop @unblock_queue) {
		541	# this is an inlined copy of async_pool
414	my $handler = (pop @unblock_pool or new Coro \&unblock_handler_);	542	my $coro = (pop @pool or new Coro \&pool_handler);
415	$handler->{arg} = $cb;	543
		544	$coro->{_invoke} = $cb;
416	$handler->ready;	545	$coro->ready;
417	cede;	546	cede; # for short-lived callbacks, this reduces pressure on the coro pool
418	}	547	}
419		548	schedule; # sleep well
420	schedule;
421	}	549	}
422	};	550	};
		551	$unblock_scheduler->desc ("[unblock_sub scheduler]");
423		552
424	sub unblock_sub(&) {	553	sub unblock_sub(&) {
425	my $cb = shift;	554	my $cb = shift;
426		555
427	sub {	556	sub {
428	push @unblock_queue, [$cb, @_];	557	unshift @unblock_queue, [$cb, @_];
429	$unblock_scheduler->ready;	558	$unblock_scheduler->ready;
430	}	559	}
431	}	560	}
432		561
433	=back	562	=back
…		…
440		569
441	- you must make very sure that no coro is still active on global	570	- you must make very sure that no coro is still active on global
442	destruction. very bad things might happen otherwise (usually segfaults).	571	destruction. very bad things might happen otherwise (usually segfaults).
443		572
444	- this module is not thread-safe. You should only ever use this module	573	- this module is not thread-safe. You should only ever use this module
445	from the same thread (this requirement might be losened in the future	574	from the same thread (this requirement might be loosened in the future
446	to allow per-thread schedulers, but Coro::State does not yet allow	575	to allow per-thread schedulers, but Coro::State does not yet allow
447	this).	576	this).
448		577
449	=head1 SEE ALSO	578	=head1 SEE ALSO
450		579

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Comparing Coro/Coro.pm (file contents): Revision 1.98 by root, Mon Dec 4 21:56:00 2006 UTC vs. Revision 1.133 by root, Fri Sep 21 01:23:58 2007 UTC

Diff Legend

Comparing Coro/Coro.pm (file contents):
Revision 1.98 by root, Mon Dec 4 21:56:00 2006 UTC vs.
Revision 1.133 by root, Fri Sep 21 01:23:58 2007 UTC