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

Comparing Coro/Coro.pm (file contents):
Revision 1.100 by root, Tue Dec 12 13:56:45 2006 UTC vs.
Revision 1.141 by root, Tue Oct 2 10:38:17 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 = '3.2';	55	our $VERSION = '3.8';
56		56
57	our @EXPORT = qw(async cede schedule terminate current unblock_sub);	57	our @EXPORT = qw(async async_pool cede schedule terminate current unblock_sub);
58	our %EXPORT_TAGS = (	58	our %EXPORT_TAGS = (
59	prio => [qw(PRIO_MAX PRIO_HIGH PRIO_NORMAL PRIO_LOW PRIO_IDLE PRIO_MIN)],	59	prio => [qw(PRIO_MAX PRIO_HIGH PRIO_NORMAL PRIO_LOW PRIO_IDLE PRIO_MIN)],
60	);	60	);
61	our @EXPORT_OK = (@{$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::POOL_RSS) it will also exit.
		233
		234	=cut
		235
		236	our $POOL_SIZE = 8;
		237	our $POOL_RSS = 16 * 1024;
		238	our @async_pool;
		239
		240	sub pool_handler {
		241	my $cb;
		242
		243	while () {
		244	eval {
		245	while () {
		246	_pool_1 $cb;
		247	&$cb;
		248	_pool_2 $cb;
		249	&schedule;
		250	}
		251	};
		252
		253	last if $@ eq "\3terminate\2\n";
		254	warn $@ if $@;
		255	}
		256	}
		257
		258	sub async_pool(&@) {
		259	# this is also inlined into the unlock_scheduler
		260	my $coro = (pop @async_pool) \|\| new Coro \&pool_handler;
		261
		262	$coro->{_invoke} = [@_];
		263	$coro->ready;
		264
		265	$coro
203	}	266	}
204		267
205	=item schedule	268	=item schedule
206		269
207	Calls the scheduler. Please note that the current coroutine will not be put	270	Calls the scheduler. Please note that the current coroutine will not be put
…		…
220	# wake up sleeping coroutine	283	# wake up sleeping coroutine
221	$current->ready;	284	$current->ready;
222	undef $current;	285	undef $current;
223	};	286	};
224		287
225	# call schedule until event occured.	288	# call schedule until event occurred.
226	# in case we are woken up for other reasons	289	# in case we are woken up for other reasons
227	# (current still defined), loop.	290	# (current still defined), loop.
228	Coro::schedule while $current;	291	Coro::schedule while $current;
229	}	292	}
230		293
…		…
232		295
233	"Cede" to other coroutines. This function puts the current coroutine into the	296	"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	297	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.	298	current "timeslice" to other coroutines of the same or higher priority.
236		299
		300	Returns true if at least one coroutine switch has happened.
		301
		302	=item Coro::cede_notself
		303
		304	Works like cede, but is not exported by default and will cede to any
		305	coroutine, regardless of priority, once.
		306
		307	Returns true if at least one coroutine switch has happened.
		308
237	=item terminate [arg...]	309	=item terminate [arg...]
238		310
239	Terminates the current coroutine with the given status values (see L<cancel>).	311	Terminates the current coroutine with the given status values (see L<cancel>).
		312
		313	=item killall
		314
		315	Kills/terminates/cancels all coroutines except the currently running
		316	one. This is useful after a fork, either in the child or the parent, as
		317	usually only one of them should inherit the running coroutines.
240		318
241	=cut	319	=cut
242		320
243	sub terminate {	321	sub terminate {
244	$current->cancel (@_);	322	$current->cancel (@_);
		323	}
		324
		325	sub killall {
		326	for (Coro::State::list) {
		327	$_->cancel
		328	if $_ != $current && UNIVERSAL::isa $_, "Coro";
		329	}
245	}	330	}
246		331
247	=back	332	=back
248		333
249	# dynamic methods	334	# dynamic methods
…		…
259	Create a new coroutine and return it. When the sub returns the coroutine	344	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	345	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	346	called. To make the coroutine run you must first put it into the ready queue
262	by calling the ready method.	347	by calling the ready method.
263		348
264	Calling C<exit> in a coroutine will not work correctly, so do not do that.	349	See C<async> for additional discussion.
265		350
266	=cut	351	=cut
267		352
268	sub _run_coro {	353	sub _run_coro {
269	terminate &{+shift};	354	terminate &{+shift};
…		…
286	Return wether the coroutine is currently the ready queue or not,	371	Return wether the coroutine is currently the ready queue or not,
287		372
288	=item $coroutine->cancel (arg...)	373	=item $coroutine->cancel (arg...)
289		374
290	Terminates the given coroutine and makes it return the given arguments as	375	Terminates the given coroutine and makes it return the given arguments as
291	status (default: the empty list).	376	status (default: the empty list). Never returns if the coroutine is the
		377	current coroutine.
292		378
293	=cut	379	=cut
294		380
295	sub cancel {	381	sub cancel {
296	my $self = shift;	382	my $self = shift;
297	$self->{status} = [@_];	383	$self->{status} = [@_];
		384
		385	if ($current == $self) {
298	push @destroy, $self;	386	push @destroy, $self;
299	$manager->ready;	387	$manager->ready;
300	&schedule if $current == $self;	388	&schedule while 1;
		389	} else {
		390	$self->_cancel;
		391	}
301	}	392	}
302		393
303	=item $coroutine->join	394	=item $coroutine->join
304		395
305	Wait until the coroutine terminates and return any values given to the	396	Wait until the coroutine terminates and return any values given to the
…		…
308		399
309	=cut	400	=cut
310		401
311	sub join {	402	sub join {
312	my $self = shift;	403	my $self = shift;
		404
313	unless ($self->{status}) {	405	unless ($self->{status}) {
314	push @{$self->{join}}, $current;	406	my $current = $current;
315	&schedule;	407
		408	push @{$self->{destroy_cb}}, sub {
		409	$current->ready;
		410	undef $current;
		411	};
		412
		413	&schedule while $current;
316	}	414	}
		415
317	wantarray ? @{$self->{status}} : $self->{status}[0];	416	wantarray ? @{$self->{status}} : $self->{status}[0];
		417	}
		418
		419	=item $coroutine->on_destroy (\&cb)
		420
		421	Registers a callback that is called when this coroutine gets destroyed,
		422	but before it is joined. The callback gets passed the terminate arguments,
		423	if any.
		424
		425	=cut
		426
		427	sub on_destroy {
		428	my ($self, $cb) = @_;
		429
		430	push @{ $self->{destroy_cb} }, $cb;
318	}	431	}
319		432
320	=item $oldprio = $coroutine->prio ($newprio)	433	=item $oldprio = $coroutine->prio ($newprio)
321		434
322	Sets (or gets, if the argument is missing) the priority of the	435	Sets (or gets, if the argument is missing) the priority of the
…		…
364	=over 4	477	=over 4
365		478
366	=item Coro::nready	479	=item Coro::nready
367		480
368	Returns the number of coroutines that are currently in the ready state,	481	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	482	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,	483	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	484	and C<schedule> would cause a deadlock unless there is an idle handler
372	that wakes up some coroutines.	485	that wakes up some coroutines.
		486
		487	=item my $guard = Coro::guard { ... }
		488
		489	This creates and returns a guard object. Nothing happens until the object
		490	gets destroyed, in which case the codeblock given as argument will be
		491	executed. This is useful to free locks or other resources in case of a
		492	runtime error or when the coroutine gets canceled, as in both cases the
		493	guard block will be executed. The guard object supports only one method,
		494	C<< ->cancel >>, which will keep the codeblock from being executed.
		495
		496	Example: set some flag and clear it again when the coroutine gets canceled
		497	or the function returns:
		498
		499	sub do_something {
		500	my $guard = Coro::guard { $busy = 0 };
		501	$busy = 1;
		502
		503	# do something that requires $busy to be true
		504	}
		505
		506	=cut
		507
		508	sub guard(&) {
		509	bless \(my $cb = $_[0]), "Coro::guard"
		510	}
		511
		512	sub Coro::guard::cancel {
		513	${$_[0]} = sub { };
		514	}
		515
		516	sub Coro::guard::DESTROY {
		517	${$_[0]}->();
		518	}
		519
373		520
374	=item unblock_sub { ... }	521	=item unblock_sub { ... }
375		522
376	This utility function takes a BLOCK or code reference and "unblocks" it,	523	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	524	returning the new coderef. This means that the new coderef will return
378	immediately without blocking, returning nothing, while the original code	525	immediately without blocking, returning nothing, while the original code
379	ref will be called (with parameters) from within its own coroutine.	526	ref will be called (with parameters) from within its own coroutine.
380		527
381	The reason this fucntion exists is that many event libraries (such as the	528	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	529	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,	530	of thread-safety). This means you must not block within event callbacks,
384	otherwise you might suffer from crashes or worse.	531	otherwise you might suffer from crashes or worse.
385		532
386	This function allows your callbacks to block by executing them in another	533	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	538	In short: simply use C<unblock_sub { ... }> instead of C<sub { ... }> when
392	creating event callbacks that want to block.	539	creating event callbacks that want to block.
393		540
394	=cut	541	=cut
395		542
396	our @unblock_pool;
397	our @unblock_queue;	543	our @unblock_queue;
398	our $UNBLOCK_POOL_SIZE = 2;
399		544
400	sub unblock_handler_ {	545	# we create a special coro because we want to cede,
401	while () {	546	# to reduce pressure on the coro pool (because most callbacks
402	my ($cb, @arg) = @{ delete $Coro::current->{arg} };	547	# return immediately and can be reused) and because we cannot cede
403	$cb->(@arg);	548	# 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 {	549	our $unblock_scheduler = new Coro sub {
412	while () {	550	while () {
413	while (my $cb = pop @unblock_queue) {	551	while (my $cb = pop @unblock_queue) {
414	my $handler = (pop @unblock_pool or new Coro \&unblock_handler_);	552	# this is an inlined copy of async_pool
415	$handler->{arg} = $cb;	553	my $coro = (pop @async_pool) \|\| new Coro \&pool_handler;
		554
		555	$coro->{_invoke} = $cb;
416	$handler->ready;	556	$coro->ready;
417	cede;	557	cede; # for short-lived callbacks, this reduces pressure on the coro pool
418	}	558	}
419		559	schedule; # sleep well
420	schedule;
421	}	560	}
422	};	561	};
		562	$unblock_scheduler->desc ("[unblock_sub scheduler]");
423		563
424	sub unblock_sub(&) {	564	sub unblock_sub(&) {
425	my $cb = shift;	565	my $cb = shift;
426		566
427	sub {	567	sub {
428	push @unblock_queue, [$cb, @_];	568	unshift @unblock_queue, [$cb, @_];
429	$unblock_scheduler->ready;	569	$unblock_scheduler->ready;
430	}	570	}
431	}	571	}
432		572
433	=back	573	=back
…		…
440		580
441	- you must make very sure that no coro is still active on global	581	- you must make very sure that no coro is still active on global
442	destruction. very bad things might happen otherwise (usually segfaults).	582	destruction. very bad things might happen otherwise (usually segfaults).
443		583
444	- this module is not thread-safe. You should only ever use this module	584	- 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	585	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	586	to allow per-thread schedulers, but Coro::State does not yet allow
447	this).	587	this).
448		588
449	=head1 SEE ALSO	589	=head1 SEE ALSO
450		590

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Comparing Coro/Coro.pm (file contents): Revision 1.100 by root, Tue Dec 12 13:56:45 2006 UTC vs. Revision 1.141 by root, Tue Oct 2 10:38:17 2007 UTC

Diff Legend

Comparing Coro/Coro.pm (file contents):
Revision 1.100 by root, Tue Dec 12 13:56:45 2006 UTC vs.
Revision 1.141 by root, Tue Oct 2 10:38:17 2007 UTC