[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 1.134 by root, Sat Sep 22 14:42:56 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 $VERSION = '3.7';
56		56
57	our @EXPORT = qw(async cede schedule terminate current unblock_sub);	57	our @EXPORT = qw(async async_pool cede schedule terminate current unblock_sub);
58	our %EXPORT_TAGS = (	58	our %EXPORT_TAGS = (
59	prio => [qw(PRIO_MAX PRIO_HIGH PRIO_NORMAL PRIO_LOW PRIO_IDLE PRIO_MIN)],	59	prio => [qw(PRIO_MAX PRIO_HIGH PRIO_NORMAL PRIO_LOW PRIO_IDLE PRIO_MIN)],
60	);	60	);
61	our @EXPORT_OK = (@{$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::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	$cb = &_pool_1
		247	or return;
		248
		249	&$cb;
		250
		251	return if &_pool_2;
		252
		253	undef $cb;
		254	schedule;
		255	}
		256	};
		257
		258	warn $@ if $@;
		259	}
		260	}
		261
		262	sub async_pool(&@) {
		263	# this is also inlined into the unlock_scheduler
		264	my $coro = (pop @async_pool) \|\| new Coro \&pool_handler;;
		265
		266	$coro->{_invoke} = [@_];
		267	$coro->ready;
		268
		269	$coro
203	}	270	}
204		271
205	=item schedule	272	=item schedule
206		273
207	Calls the scheduler. Please note that the current coroutine will not be put	274	Calls the scheduler. Please note that the current coroutine will not be put
…		…
220	# wake up sleeping coroutine	287	# wake up sleeping coroutine
221	$current->ready;	288	$current->ready;
222	undef $current;	289	undef $current;
223	};	290	};
224		291
225	# call schedule until event occured.	292	# call schedule until event occurred.
226	# in case we are woken up for other reasons	293	# in case we are woken up for other reasons
227	# (current still defined), loop.	294	# (current still defined), loop.
228	Coro::schedule while $current;	295	Coro::schedule while $current;
229	}	296	}
230		297
231	=item cede	298	=item cede
232		299
233	"Cede" to other coroutines. This function puts the current coroutine into the	300	"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	301	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.	302	current "timeslice" to other coroutines of the same or higher priority.
		303
		304	Returns true if at least one coroutine switch has happened.
		305
		306	=item Coro::cede_notself
		307
		308	Works like cede, but is not exported by default and will cede to any
		309	coroutine, regardless of priority, once.
		310
		311	Returns true if at least one coroutine switch has happened.
236		312
237	=item terminate [arg...]	313	=item terminate [arg...]
238		314
239	Terminates the current coroutine with the given status values (see L<cancel>).	315	Terminates the current coroutine with the given status values (see L<cancel>).
240		316
…		…
259	Create a new coroutine and return it. When the sub returns the coroutine	335	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	336	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	337	called. To make the coroutine run you must first put it into the ready queue
262	by calling the ready method.	338	by calling the ready method.
263		339
264	Calling C<exit> in a coroutine will not work correctly, so do not do that.	340	See C<async> for additional discussion.
265		341
266	=cut	342	=cut
267		343
268	sub _run_coro {	344	sub _run_coro {
269	terminate &{+shift};	345	terminate &{+shift};
…		…
286	Return wether the coroutine is currently the ready queue or not,	362	Return wether the coroutine is currently the ready queue or not,
287		363
288	=item $coroutine->cancel (arg...)	364	=item $coroutine->cancel (arg...)
289		365
290	Terminates the given coroutine and makes it return the given arguments as	366	Terminates the given coroutine and makes it return the given arguments as
291	status (default: the empty list).	367	status (default: the empty list). Never returns if the coroutine is the
		368	current coroutine.
292		369
293	=cut	370	=cut
294		371
295	sub cancel {	372	sub cancel {
296	my $self = shift;	373	my $self = shift;
297	$self->{status} = [@_];	374	$self->{status} = [@_];
		375
		376	if ($current == $self) {
298	push @destroy, $self;	377	push @destroy, $self;
299	$manager->ready;	378	$manager->ready;
300	&schedule if $current == $self;	379	&schedule while 1;
		380	} else {
		381	$self->_cancel;
		382	}
301	}	383	}
302		384
303	=item $coroutine->join	385	=item $coroutine->join
304		386
305	Wait until the coroutine terminates and return any values given to the	387	Wait until the coroutine terminates and return any values given to the
…		…
308		390
309	=cut	391	=cut
310		392
311	sub join {	393	sub join {
312	my $self = shift;	394	my $self = shift;
		395
313	unless ($self->{status}) {	396	unless ($self->{status}) {
314	push @{$self->{join}}, $current;	397	my $current = $current;
315	&schedule;	398
		399	push @{$self->{destroy_cb}}, sub {
		400	$current->ready;
		401	undef $current;
		402	};
		403
		404	&schedule while $current;
316	}	405	}
		406
317	wantarray ? @{$self->{status}} : $self->{status}[0];	407	wantarray ? @{$self->{status}} : $self->{status}[0];
		408	}
		409
		410	=item $coroutine->on_destroy (\&cb)
		411
		412	Registers a callback that is called when this coroutine gets destroyed,
		413	but before it is joined. The callback gets passed the terminate arguments,
		414	if any.
		415
		416	=cut
		417
		418	sub on_destroy {
		419	my ($self, $cb) = @_;
		420
		421	push @{ $self->{destroy_cb} }, $cb;
318	}	422	}
319		423
320	=item $oldprio = $coroutine->prio ($newprio)	424	=item $oldprio = $coroutine->prio ($newprio)
321		425
322	Sets (or gets, if the argument is missing) the priority of the	426	Sets (or gets, if the argument is missing) the priority of the
…		…
364	=over 4	468	=over 4
365		469
366	=item Coro::nready	470	=item Coro::nready
367		471
368	Returns the number of coroutines that are currently in the ready state,	472	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	473	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,	474	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	475	and C<schedule> would cause a deadlock unless there is an idle handler
372	that wakes up some coroutines.	476	that wakes up some coroutines.
		477
		478	=item my $guard = Coro::guard { ... }
		479
		480	This creates and returns a guard object. Nothing happens until the object
		481	gets destroyed, in which case the codeblock given as argument will be
		482	executed. This is useful to free locks or other resources in case of a
		483	runtime error or when the coroutine gets canceled, as in both cases the
		484	guard block will be executed. The guard object supports only one method,
		485	C<< ->cancel >>, which will keep the codeblock from being executed.
		486
		487	Example: set some flag and clear it again when the coroutine gets canceled
		488	or the function returns:
		489
		490	sub do_something {
		491	my $guard = Coro::guard { $busy = 0 };
		492	$busy = 1;
		493
		494	# do something that requires $busy to be true
		495	}
		496
		497	=cut
		498
		499	sub guard(&) {
		500	bless \(my $cb = $_[0]), "Coro::guard"
		501	}
		502
		503	sub Coro::guard::cancel {
		504	${$_[0]} = sub { };
		505	}
		506
		507	sub Coro::guard::DESTROY {
		508	${$_[0]}->();
		509	}
		510
373		511
374	=item unblock_sub { ... }	512	=item unblock_sub { ... }
375		513
376	This utility function takes a BLOCK or code reference and "unblocks" it,	514	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	515	returning the new coderef. This means that the new coderef will return
378	immediately without blocking, returning nothing, while the original code	516	immediately without blocking, returning nothing, while the original code
379	ref will be called (with parameters) from within its own coroutine.	517	ref will be called (with parameters) from within its own coroutine.
380		518
381	The reason this fucntion exists is that many event libraries (such as the	519	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	520	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,	521	of thread-safety). This means you must not block within event callbacks,
384	otherwise you might suffer from crashes or worse.	522	otherwise you might suffer from crashes or worse.
385		523
386	This function allows your callbacks to block by executing them in another	524	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	529	In short: simply use C<unblock_sub { ... }> instead of C<sub { ... }> when
392	creating event callbacks that want to block.	530	creating event callbacks that want to block.
393		531
394	=cut	532	=cut
395		533
396	our @unblock_pool;
397	our @unblock_queue;	534	our @unblock_queue;
398	our $UNBLOCK_POOL_SIZE = 2;
399		535
400	sub unblock_handler_ {	536	# we create a special coro because we want to cede,
401	while () {	537	# to reduce pressure on the coro pool (because most callbacks
402	my ($cb, @arg) = @{ delete $Coro::current->{arg} };	538	# return immediately and can be reused) and because we cannot cede
403	$cb->(@arg);	539	# 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 {	540	our $unblock_scheduler = new Coro sub {
412	while () {	541	while () {
413	while (my $cb = pop @unblock_queue) {	542	while (my $cb = pop @unblock_queue) {
414	my $handler = (pop @unblock_pool or new Coro \&unblock_handler_);	543	# this is an inlined copy of async_pool
415	$handler->{arg} = $cb;	544	my $coro = (pop @async_pool) \|\| new Coro \&pool_handler;
		545
		546	$coro->{_invoke} = $cb;
416	$handler->ready;	547	$coro->ready;
417	cede;	548	cede; # for short-lived callbacks, this reduces pressure on the coro pool
418	}	549	}
419		550	schedule; # sleep well
420	schedule;
421	}	551	}
422	};	552	};
		553	$unblock_scheduler->desc ("[unblock_sub scheduler]");
423		554
424	sub unblock_sub(&) {	555	sub unblock_sub(&) {
425	my $cb = shift;	556	my $cb = shift;
426		557
427	sub {	558	sub {
428	push @unblock_queue, [$cb, @_];	559	unshift @unblock_queue, [$cb, @_];
429	$unblock_scheduler->ready;	560	$unblock_scheduler->ready;
430	}	561	}
431	}	562	}
432		563
433	=back	564	=back
…		…
440		571
441	- you must make very sure that no coro is still active on global	572	- you must make very sure that no coro is still active on global
442	destruction. very bad things might happen otherwise (usually segfaults).	573	destruction. very bad things might happen otherwise (usually segfaults).
443		574
444	- this module is not thread-safe. You should only ever use this module	575	- 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	576	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	577	to allow per-thread schedulers, but Coro::State does not yet allow
447	this).	578	this).
448		579
449	=head1 SEE ALSO	580	=head1 SEE ALSO
450		581

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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 1.134 by root, Sat Sep 22 14:42:56 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 1.134 by root, Sat Sep 22 14:42:56 2007 UTC