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

Comparing Coro/Coro.pm (file contents):
Revision 1.102 by root, Fri Dec 29 11:37:49 2006 UTC vs.
Revision 1.148 by root, Fri Oct 5 20:11:25 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 = '3.3';	55	our $VERSION = '4.01';
56		56
57	our @EXPORT = qw(async cede schedule terminate current unblock_sub);	57	our @EXPORT = qw(async async_pool cede schedule terminate current unblock_sub);
58	our %EXPORT_TAGS = (	58	our %EXPORT_TAGS = (
59	prio => [qw(PRIO_MAX PRIO_HIGH PRIO_NORMAL PRIO_LOW PRIO_IDLE PRIO_MIN)],	59	prio => [qw(PRIO_MAX PRIO_HIGH PRIO_NORMAL PRIO_LOW PRIO_IDLE PRIO_MIN)],
60	);	60	);
61	our @EXPORT_OK = (@{$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		117
		118	$main->{desc} = "[main::]";
		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
122	_set_current $main;	124	_set_current $main;
123		125
124	sub current() { $current }	126	sub current() { $current }
…		…
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->{_on_destroy}) \|\| []};
		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		169
159	$coro->{status} \|\|= [];
160
161	$_->ready for @{(delete $coro->{join} ) \|\| []};
162	$_->(@{$coro->{status}}) for @{(delete $coro->{destroy_cb}) \|\| []};
163
164	# the next line destroys the coro state, but keeps the
165	# coroutine itself intact (we basically make it a zombie
166	# coroutine that always runs the manager thread, so it's possible
167	# to transfer() to this coroutine).
168	$coro->_clone_state_from ($manager);
169	}
170	&schedule;	170	&schedule;
171	}	171	}
172	};	172	};
		173	$manager->desc ("[coro manager]");
		174	$manager->prio (PRIO_MAX);
173		175
174	# static methods. not really.	176	# static methods. not really.
175		177
176	=back	178	=back
177		179
…		…
185		187
186	Create a new asynchronous coroutine and return it's coroutine object	188	Create a new asynchronous coroutine and return it's coroutine object
187	(usually unused). When the sub returns the new coroutine is automatically	189	(usually unused). When the sub returns the new coroutine is automatically
188	terminated.	190	terminated.
189		191
190	Calling C<exit> in a coroutine will not work correctly, so do not do that.	192	See the C<Coro::State::new> constructor for info about the coroutine
		193	environment.
191		194
192	When the coroutine dies, the program will exit, just as in the main	195	Calling C<exit> in a coroutine will do the same as calling exit outside
193	program.	196	the coroutine. Likewise, when the coroutine dies, the program will exit,
		197	just as it would in the main program.
194		198
195	# create a new coroutine that just prints its arguments	199	# create a new coroutine that just prints its arguments
196	async {	200	async {
197	print "@_\n";	201	print "@_\n";
198	} 1,2,3,4;	202	} 1,2,3,4;
199		203
200	=cut	204	=cut
201		205
202	sub async(&@) {	206	sub async(&@) {
203	my $pid = new Coro @_;	207	my $coro = new Coro @_;
204	$pid->ready;	208	$coro->ready;
205	$pid	209	$coro
		210	}
		211
		212	=item async_pool { ... } [@args...]
		213
		214	Similar to C<async>, but uses a coroutine pool, so you should not call
		215	terminate or join (although you are allowed to), and you get a coroutine
		216	that might have executed other code already (which can be good or bad :).
		217
		218	Also, the block is executed in an C<eval> context and a warning will be
		219	issued in case of an exception instead of terminating the program, as
		220	C<async> does. As the coroutine is being reused, stuff like C<on_destroy>
		221	will not work in the expected way, unless you call terminate or cancel,
		222	which somehow defeats the purpose of pooling.
		223
		224	The priority will be reset to C<0> after each job, tracing will be
		225	disabled, the description will be reset and the default output filehandle
		226	gets restored, so you can change alkl these. Otherwise the coroutine will
		227	be re-used "as-is": most notably if you change other per-coroutine global
		228	stuff such as C<$/> you need to revert that change, which is most simply
		229	done by using local as in C< local $/ >.
		230
		231	The pool size is limited to 8 idle coroutines (this can be adjusted by
		232	changing $Coro::POOL_SIZE), and there can be as many non-idle coros as
		233	required.
		234
		235	If you are concerned about pooled coroutines growing a lot because a
		236	single C<async_pool> used a lot of stackspace you can e.g. C<async_pool
		237	{ terminate }> once per second or so to slowly replenish the pool. In
		238	addition to that, when the stacks used by a handler grows larger than 16kb
		239	(adjustable with $Coro::POOL_RSS) it will also exit.
		240
		241	=cut
		242
		243	our $POOL_SIZE = 8;
		244	our $POOL_RSS = 16 * 1024;
		245	our @async_pool;
		246
		247	sub pool_handler {
		248	my $cb;
		249
		250	while () {
		251	eval {
		252	while () {
		253	_pool_1 $cb;
		254	&$cb;
		255	_pool_2 $cb;
		256	&schedule;
		257	}
		258	};
		259
		260	last if $@ eq "\3terminate\2\n";
		261	warn $@ if $@;
		262	}
		263	}
		264
		265	sub async_pool(&@) {
		266	# this is also inlined into the unlock_scheduler
		267	my $coro = (pop @async_pool) \|\| new Coro \&pool_handler;
		268
		269	$coro->{_invoke} = [@_];
		270	$coro->ready;
		271
		272	$coro
206	}	273	}
207		274
208	=item schedule	275	=item schedule
209		276
210	Calls the scheduler. Please note that the current coroutine will not be put	277	Calls the scheduler. Please note that the current coroutine will not be put
…		…
223	# wake up sleeping coroutine	290	# wake up sleeping coroutine
224	$current->ready;	291	$current->ready;
225	undef $current;	292	undef $current;
226	};	293	};
227		294
228	# call schedule until event occured.	295	# call schedule until event occurred.
229	# in case we are woken up for other reasons	296	# in case we are woken up for other reasons
230	# (current still defined), loop.	297	# (current still defined), loop.
231	Coro::schedule while $current;	298	Coro::schedule while $current;
232	}	299	}
233		300
…		…
235		302
236	"Cede" to other coroutines. This function puts the current coroutine into the	303	"Cede" to other coroutines. This function puts the current coroutine into the
237	ready queue and calls C<schedule>, which has the effect of giving up the	304	ready queue and calls C<schedule>, which has the effect of giving up the
238	current "timeslice" to other coroutines of the same or higher priority.	305	current "timeslice" to other coroutines of the same or higher priority.
239		306
		307	Returns true if at least one coroutine switch has happened.
		308
240	=item Coro::cede_notself	309	=item Coro::cede_notself
241		310
242	Works like cede, but is not exported by default and will cede to any	311	Works like cede, but is not exported by default and will cede to any
243	coroutine, regardless of priority, once.	312	coroutine, regardless of priority, once.
244		313
		314	Returns true if at least one coroutine switch has happened.
		315
245	=item terminate [arg...]	316	=item terminate [arg...]
246		317
247	Terminates the current coroutine with the given status values (see L<cancel>).	318	Terminates the current coroutine with the given status values (see L<cancel>).
		319
		320	=item killall
		321
		322	Kills/terminates/cancels all coroutines except the currently running
		323	one. This is useful after a fork, either in the child or the parent, as
		324	usually only one of them should inherit the running coroutines.
248		325
249	=cut	326	=cut
250		327
251	sub terminate {	328	sub terminate {
252	$current->cancel (@_);	329	$current->cancel (@_);
		330	}
		331
		332	sub killall {
		333	for (Coro::State::list) {
		334	$_->cancel
		335	if $_ != $current && UNIVERSAL::isa $_, "Coro";
		336	}
253	}	337	}
254		338
255	=back	339	=back
256		340
257	# dynamic methods	341	# dynamic methods
…		…
267	Create a new coroutine and return it. When the sub returns the coroutine	351	Create a new coroutine and return it. When the sub returns the coroutine
268	automatically terminates as if C<terminate> with the returned values were	352	automatically terminates as if C<terminate> with the returned values were
269	called. To make the coroutine run you must first put it into the ready queue	353	called. To make the coroutine run you must first put it into the ready queue
270	by calling the ready method.	354	by calling the ready method.
271		355
272	Calling C<exit> in a coroutine will not work correctly, so do not do that.	356	See C<async> and C<Coro::State::new> for additional info about the
		357	coroutine environment.
273		358
274	=cut	359	=cut
275		360
276	sub _run_coro {	361	sub _run_coro {
277	terminate &{+shift};	362	terminate &{+shift};
…		…
294	Return wether the coroutine is currently the ready queue or not,	379	Return wether the coroutine is currently the ready queue or not,
295		380
296	=item $coroutine->cancel (arg...)	381	=item $coroutine->cancel (arg...)
297		382
298	Terminates the given coroutine and makes it return the given arguments as	383	Terminates the given coroutine and makes it return the given arguments as
299	status (default: the empty list).	384	status (default: the empty list). Never returns if the coroutine is the
		385	current coroutine.
300		386
301	=cut	387	=cut
302		388
303	sub cancel {	389	sub cancel {
304	my $self = shift;	390	my $self = shift;
305	$self->{status} = [@_];	391	$self->{_status} = [@_];
		392
		393	if ($current == $self) {
306	push @destroy, $self;	394	push @destroy, $self;
307	$manager->ready;	395	$manager->ready;
308	&schedule if $current == $self;	396	&schedule while 1;
		397	} else {
		398	$self->_cancel;
		399	}
309	}	400	}
310		401
311	=item $coroutine->join	402	=item $coroutine->join
312		403
313	Wait until the coroutine terminates and return any values given to the	404	Wait until the coroutine terminates and return any values given to the
314	C<terminate> or C<cancel> functions. C<join> can be called multiple times	405	C<terminate> or C<cancel> functions. C<join> can be called concurrently
315	from multiple coroutine.	406	from multiple coroutines.
316		407
317	=cut	408	=cut
318		409
319	sub join {	410	sub join {
320	my $self = shift;	411	my $self = shift;
		412
321	unless ($self->{status}) {	413	unless ($self->{_status}) {
322	push @{$self->{join}}, $current;	414	my $current = $current;
323	&schedule;	415
		416	push @{$self->{_on_destroy}}, sub {
		417	$current->ready;
		418	undef $current;
		419	};
		420
		421	&schedule while $current;
324	}	422	}
		423
325	wantarray ? @{$self->{status}} : $self->{status}[0];	424	wantarray ? @{$self->{_status}} : $self->{_status}[0];
326	}	425	}
327		426
328	=item $coroutine->on_destroy (\&cb)	427	=item $coroutine->on_destroy (\&cb)
329		428
330	Registers a callback that is called when this coroutine gets destroyed,	429	Registers a callback that is called when this coroutine gets destroyed,
…		…
334	=cut	433	=cut
335		434
336	sub on_destroy {	435	sub on_destroy {
337	my ($self, $cb) = @_;	436	my ($self, $cb) = @_;
338		437
339	push @{ $self->{destroy_cb} }, $cb;	438	push @{ $self->{_on_destroy} }, $cb;
340	}	439	}
341		440
342	=item $oldprio = $coroutine->prio ($newprio)	441	=item $oldprio = $coroutine->prio ($newprio)
343		442
344	Sets (or gets, if the argument is missing) the priority of the	443	Sets (or gets, if the argument is missing) the priority of the
…		…
369	=item $olddesc = $coroutine->desc ($newdesc)	468	=item $olddesc = $coroutine->desc ($newdesc)
370		469
371	Sets (or gets in case the argument is missing) the description for this	470	Sets (or gets in case the argument is missing) the description for this
372	coroutine. This is just a free-form string you can associate with a coroutine.	471	coroutine. This is just a free-form string you can associate with a coroutine.
373		472
		473	This method simply sets the C<< $coroutine->{desc} >> member to the given string. You
		474	can modify this member directly if you wish.
		475
374	=cut	476	=cut
375		477
376	sub desc {	478	sub desc {
377	my $old = $_[0]{desc};	479	my $old = $_[0]{desc};
378	$_[0]{desc} = $_[1] if @_ > 1;	480	$_[0]{desc} = $_[1] if @_ > 1;
…		…
386	=over 4	488	=over 4
387		489
388	=item Coro::nready	490	=item Coro::nready
389		491
390	Returns the number of coroutines that are currently in the ready state,	492	Returns the number of coroutines that are currently in the ready state,
391	i.e. that can be swicthed to. The value C<0> means that the only runnable	493	i.e. that can be switched to. The value C<0> means that the only runnable
392	coroutine is the currently running one, so C<cede> would have no effect,	494	coroutine is the currently running one, so C<cede> would have no effect,
393	and C<schedule> would cause a deadlock unless there is an idle handler	495	and C<schedule> would cause a deadlock unless there is an idle handler
394	that wakes up some coroutines.	496	that wakes up some coroutines.
		497
		498	=item my $guard = Coro::guard { ... }
		499
		500	This creates and returns a guard object. Nothing happens until the object
		501	gets destroyed, in which case the codeblock given as argument will be
		502	executed. This is useful to free locks or other resources in case of a
		503	runtime error or when the coroutine gets canceled, as in both cases the
		504	guard block will be executed. The guard object supports only one method,
		505	C<< ->cancel >>, which will keep the codeblock from being executed.
		506
		507	Example: set some flag and clear it again when the coroutine gets canceled
		508	or the function returns:
		509
		510	sub do_something {
		511	my $guard = Coro::guard { $busy = 0 };
		512	$busy = 1;
		513
		514	# do something that requires $busy to be true
		515	}
		516
		517	=cut
		518
		519	sub guard(&) {
		520	bless \(my $cb = $_[0]), "Coro::guard"
		521	}
		522
		523	sub Coro::guard::cancel {
		524	${$_[0]} = sub { };
		525	}
		526
		527	sub Coro::guard::DESTROY {
		528	${$_[0]}->();
		529	}
		530
395		531
396	=item unblock_sub { ... }	532	=item unblock_sub { ... }
397		533
398	This utility function takes a BLOCK or code reference and "unblocks" it,	534	This utility function takes a BLOCK or code reference and "unblocks" it,
399	returning the new coderef. This means that the new coderef will return	535	returning the new coderef. This means that the new coderef will return
400	immediately without blocking, returning nothing, while the original code	536	immediately without blocking, returning nothing, while the original code
401	ref will be called (with parameters) from within its own coroutine.	537	ref will be called (with parameters) from within its own coroutine.
402		538
403	The reason this fucntion exists is that many event libraries (such as the	539	The reason this function exists is that many event libraries (such as the
404	venerable L<Event\|Event> module) are not coroutine-safe (a weaker form	540	venerable L<Event\|Event> module) are not coroutine-safe (a weaker form
405	of thread-safety). This means you must not block within event callbacks,	541	of thread-safety). This means you must not block within event callbacks,
406	otherwise you might suffer from crashes or worse.	542	otherwise you might suffer from crashes or worse.
407		543
408	This function allows your callbacks to block by executing them in another	544	This function allows your callbacks to block by executing them in another
…		…
413	In short: simply use C<unblock_sub { ... }> instead of C<sub { ... }> when	549	In short: simply use C<unblock_sub { ... }> instead of C<sub { ... }> when
414	creating event callbacks that want to block.	550	creating event callbacks that want to block.
415		551
416	=cut	552	=cut
417		553
418	our @unblock_pool;
419	our @unblock_queue;	554	our @unblock_queue;
420	our $UNBLOCK_POOL_SIZE = 2;
421		555
422	sub unblock_handler_ {	556	# we create a special coro because we want to cede,
423	while () {	557	# to reduce pressure on the coro pool (because most callbacks
424	my ($cb, @arg) = @{ delete $Coro::current->{arg} };	558	# return immediately and can be reused) and because we cannot cede
425	$cb->(@arg);	559	# inside an event callback.
426
427	last if @unblock_pool >= $UNBLOCK_POOL_SIZE;
428	push @unblock_pool, $Coro::current;
429	schedule;
430	}
431	}
432
433	our $unblock_scheduler = async {	560	our $unblock_scheduler = new Coro sub {
434	while () {	561	while () {
435	while (my $cb = pop @unblock_queue) {	562	while (my $cb = pop @unblock_queue) {
436	my $handler = (pop @unblock_pool or new Coro \&unblock_handler_);	563	# this is an inlined copy of async_pool
437	$handler->{arg} = $cb;	564	my $coro = (pop @async_pool) \|\| new Coro \&pool_handler;
		565
		566	$coro->{_invoke} = $cb;
438	$handler->ready;	567	$coro->ready;
439	cede;	568	cede; # for short-lived callbacks, this reduces pressure on the coro pool
440	}	569	}
441		570	schedule; # sleep well
442	schedule;
443	}	571	}
444	};	572	};
		573	$unblock_scheduler->desc ("[unblock_sub scheduler]");
445		574
446	sub unblock_sub(&) {	575	sub unblock_sub(&) {
447	my $cb = shift;	576	my $cb = shift;
448		577
449	sub {	578	sub {
450	push @unblock_queue, [$cb, @_];	579	unshift @unblock_queue, [$cb, @_];
451	$unblock_scheduler->ready;	580	$unblock_scheduler->ready;
452	}	581	}
453	}	582	}
454		583
455	=back	584	=back
…		…
462		591
463	- you must make very sure that no coro is still active on global	592	- you must make very sure that no coro is still active on global
464	destruction. very bad things might happen otherwise (usually segfaults).	593	destruction. very bad things might happen otherwise (usually segfaults).
465		594
466	- this module is not thread-safe. You should only ever use this module	595	- this module is not thread-safe. You should only ever use this module
467	from the same thread (this requirement might be losened in the future	596	from the same thread (this requirement might be loosened in the future
468	to allow per-thread schedulers, but Coro::State does not yet allow	597	to allow per-thread schedulers, but Coro::State does not yet allow
469	this).	598	this).
470		599
471	=head1 SEE ALSO	600	=head1 SEE ALSO
472		601
473	Support/Utility: L<Coro::Cont>, L<Coro::Specific>, L<Coro::State>, L<Coro::Util>.	602	Support/Utility: L<Coro::Specific>, L<Coro::State>, L<Coro::Util>.
474		603
475	Locking/IPC: L<Coro::Signal>, L<Coro::Channel>, L<Coro::Semaphore>, L<Coro::SemaphoreSet>, L<Coro::RWLock>.	604	Locking/IPC: L<Coro::Signal>, L<Coro::Channel>, L<Coro::Semaphore>, L<Coro::SemaphoreSet>, L<Coro::RWLock>.
476		605
477	Event/IO: L<Coro::Timer>, L<Coro::Event>, L<Coro::Handle>, L<Coro::Socket>, L<Coro::Select>.	606	Event/IO: L<Coro::Timer>, L<Coro::Event>, L<Coro::Handle>, L<Coro::Socket>, L<Coro::Select>.
478		607

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Comparing Coro/Coro.pm (file contents): Revision 1.102 by root, Fri Dec 29 11:37:49 2006 UTC vs. Revision 1.148 by root, Fri Oct 5 20:11:25 2007 UTC

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Comparing Coro/Coro.pm (file contents):
Revision 1.102 by root, Fri Dec 29 11:37:49 2006 UTC vs.
Revision 1.148 by root, Fri Oct 5 20:11:25 2007 UTC