[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 1.129 by root, Wed Sep 19 22:33:08 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 $VERSION = '3.7';
56		56
57	our @EXPORT = qw(async cede schedule terminate current unblock_sub);	57	our @EXPORT = qw(async async_pool cede schedule terminate current unblock_sub);
58	our %EXPORT_TAGS = (	58	our %EXPORT_TAGS = (
59	prio => [qw(PRIO_MAX PRIO_HIGH PRIO_NORMAL PRIO_LOW PRIO_IDLE PRIO_MIN)],	59	prio => [qw(PRIO_MAX PRIO_HIGH PRIO_NORMAL PRIO_LOW PRIO_IDLE PRIO_MIN)],
60	);	60	);
61	our @EXPORT_OK = (@{$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		117
118	# maybe some other module used Coro::Specific before...	118	# maybe some other module used Coro::Specific before...
…		…
141	$idle = sub {	141	$idle = sub {
142	require Carp;	142	require Carp;
143	Carp::croak ("FATAL: deadlock detected");	143	Carp::croak ("FATAL: deadlock detected");
144	};	144	};
145		145
		146	sub _cancel {
		147	my ($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	}
		157
146	# this coroutine is necessary because a coroutine	158	# this coroutine is necessary because a coroutine
147	# cannot destroy itself.	159	# cannot destroy itself.
148	my @destroy;	160	my @destroy;
		161	my $manager;
		162
149	my $manager; $manager = new Coro sub {	163	$manager = new Coro sub {
		164	$current->desc ("[coro manager]");
		165
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
		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	Calling C<exit> in a coroutine will do the same as calling exit outside
191		193	the coroutine. Likewise, when the coroutine dies, the program will exit,
192	When the coroutine dies, the program will exit, just as in the main	194	just as it would in the main program.
193	program.
194		195
195	# create a new coroutine that just prints its arguments	196	# create a new coroutine that just prints its arguments
196	async {	197	async {
197	print "@_\n";	198	print "@_\n";
198	} 1,2,3,4;	199	} 1,2,3,4;
199		200
200	=cut	201	=cut
201		202
202	sub async(&@) {	203	sub async(&@) {
203	my $pid = new Coro @_;	204	my $coro = new Coro @_;
204	$pid->ready;	205	$coro->ready;
205	$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.
		231
		232	=cut
		233
		234	our $POOL_SIZE = 8;
		235	our @pool;
		236
		237	sub pool_handler {
		238	while () {
		239	$current->{desc} = "[async_pool]";
		240
		241	eval {
		242	my ($cb, @arg) = @{ delete $current->{_invoke} or return };
		243	$cb->(@arg);
		244	};
		245	warn $@ if $@;
		246
		247	last if @pool >= $POOL_SIZE;
		248
		249	push @pool, $current;
		250	$current->{desc} = "[async_pool idle]";
		251	$current->save (Coro::State::SAVE_DEF);
		252	$current->prio (0);
		253	schedule;
		254	}
		255	}
		256
		257	sub async_pool(&@) {
		258	# this is also inlined into the unlock_scheduler
		259	my $coro = (pop @pool) \|\| new Coro \&pool_handler;;
		260
		261	$coro->{_invoke} = [@_];
		262	$coro->ready;
		263
		264	$coro
206	}	265	}
207		266
208	=item schedule	267	=item schedule
209		268
210	Calls the scheduler. Please note that the current coroutine will not be put	269	Calls the scheduler. Please note that the current coroutine will not be put
…		…
223	# wake up sleeping coroutine	282	# wake up sleeping coroutine
224	$current->ready;	283	$current->ready;
225	undef $current;	284	undef $current;
226	};	285	};
227		286
228	# call schedule until event occured.	287	# call schedule until event occurred.
229	# in case we are woken up for other reasons	288	# in case we are woken up for other reasons
230	# (current still defined), loop.	289	# (current still defined), loop.
231	Coro::schedule while $current;	290	Coro::schedule while $current;
232	}	291	}
233		292
…		…
235		294
236	"Cede" to other coroutines. This function puts the current coroutine into the	295	"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	296	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.	297	current "timeslice" to other coroutines of the same or higher priority.
239		298
		299	Returns true if at least one coroutine switch has happened.
		300
240	=item Coro::cede_notself	301	=item Coro::cede_notself
241		302
242	Works like cede, but is not exported by default and will cede to any	303	Works like cede, but is not exported by default and will cede to any
243	coroutine, regardless of priority, once.	304	coroutine, regardless of priority, once.
		305
		306	Returns true if at least one coroutine switch has happened.
244		307
245	=item terminate [arg...]	308	=item terminate [arg...]
246		309
247	Terminates the current coroutine with the given status values (see L<cancel>).	310	Terminates the current coroutine with the given status values (see L<cancel>).
248		311
…		…
267	Create a new coroutine and return it. When the sub returns the coroutine	330	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	331	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	332	called. To make the coroutine run you must first put it into the ready queue
270	by calling the ready method.	333	by calling the ready method.
271		334
272	Calling C<exit> in a coroutine will not work correctly, so do not do that.	335	See C<async> for additional discussion.
273		336
274	=cut	337	=cut
275		338
276	sub _run_coro {	339	sub _run_coro {
277	terminate &{+shift};	340	terminate &{+shift};
…		…
294	Return wether the coroutine is currently the ready queue or not,	357	Return wether the coroutine is currently the ready queue or not,
295		358
296	=item $coroutine->cancel (arg...)	359	=item $coroutine->cancel (arg...)
297		360
298	Terminates the given coroutine and makes it return the given arguments as	361	Terminates the given coroutine and makes it return the given arguments as
299	status (default: the empty list).	362	status (default: the empty list). Never returns if the coroutine is the
		363	current coroutine.
300		364
301	=cut	365	=cut
302		366
303	sub cancel {	367	sub cancel {
304	my $self = shift;	368	my $self = shift;
305	$self->{status} = [@_];	369	$self->{status} = [@_];
		370
		371	if ($current == $self) {
306	push @destroy, $self;	372	push @destroy, $self;
307	$manager->ready;	373	$manager->ready;
308	&schedule if $current == $self;	374	&schedule while 1;
		375	} else {
		376	$self->_cancel;
		377	}
309	}	378	}
310		379
311	=item $coroutine->join	380	=item $coroutine->join
312		381
313	Wait until the coroutine terminates and return any values given to the	382	Wait until the coroutine terminates and return any values given to the
…		…
316		385
317	=cut	386	=cut
318		387
319	sub join {	388	sub join {
320	my $self = shift;	389	my $self = shift;
		390
321	unless ($self->{status}) {	391	unless ($self->{status}) {
322	push @{$self->{join}}, $current;	392	my $current = $current;
323	&schedule;	393
		394	push @{$self->{destroy_cb}}, sub {
		395	$current->ready;
		396	undef $current;
		397	};
		398
		399	&schedule while $current;
324	}	400	}
		401
325	wantarray ? @{$self->{status}} : $self->{status}[0];	402	wantarray ? @{$self->{status}} : $self->{status}[0];
326	}	403	}
327		404
328	=item $coroutine->on_destroy (\&cb)	405	=item $coroutine->on_destroy (\&cb)
329		406
…		…
386	=over 4	463	=over 4
387		464
388	=item Coro::nready	465	=item Coro::nready
389		466
390	Returns the number of coroutines that are currently in the ready state,	467	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	468	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,	469	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	470	and C<schedule> would cause a deadlock unless there is an idle handler
394	that wakes up some coroutines.	471	that wakes up some coroutines.
		472
		473	=item my $guard = Coro::guard { ... }
		474
		475	This creates and returns a guard object. Nothing happens until the object
		476	gets destroyed, in which case the codeblock given as argument will be
		477	executed. This is useful to free locks or other resources in case of a
		478	runtime error or when the coroutine gets canceled, as in both cases the
		479	guard block will be executed. The guard object supports only one method,
		480	C<< ->cancel >>, which will keep the codeblock from being executed.
		481
		482	Example: set some flag and clear it again when the coroutine gets canceled
		483	or the function returns:
		484
		485	sub do_something {
		486	my $guard = Coro::guard { $busy = 0 };
		487	$busy = 1;
		488
		489	# do something that requires $busy to be true
		490	}
		491
		492	=cut
		493
		494	sub guard(&) {
		495	bless \(my $cb = $_[0]), "Coro::guard"
		496	}
		497
		498	sub Coro::guard::cancel {
		499	${$_[0]} = sub { };
		500	}
		501
		502	sub Coro::guard::DESTROY {
		503	${$_[0]}->();
		504	}
		505
395		506
396	=item unblock_sub { ... }	507	=item unblock_sub { ... }
397		508
398	This utility function takes a BLOCK or code reference and "unblocks" it,	509	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	510	returning the new coderef. This means that the new coderef will return
400	immediately without blocking, returning nothing, while the original code	511	immediately without blocking, returning nothing, while the original code
401	ref will be called (with parameters) from within its own coroutine.	512	ref will be called (with parameters) from within its own coroutine.
402		513
403	The reason this fucntion exists is that many event libraries (such as the	514	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	515	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,	516	of thread-safety). This means you must not block within event callbacks,
406	otherwise you might suffer from crashes or worse.	517	otherwise you might suffer from crashes or worse.
407		518
408	This function allows your callbacks to block by executing them in another	519	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	524	In short: simply use C<unblock_sub { ... }> instead of C<sub { ... }> when
414	creating event callbacks that want to block.	525	creating event callbacks that want to block.
415		526
416	=cut	527	=cut
417		528
418	our @unblock_pool;
419	our @unblock_queue;	529	our @unblock_queue;
420	our $UNBLOCK_POOL_SIZE = 2;
421		530
422	sub unblock_handler_ {	531	# we create a special coro because we want to cede,
423	while () {	532	# to reduce pressure on the coro pool (because most callbacks
424	my ($cb, @arg) = @{ delete $Coro::current->{arg} };	533	# return immediately and can be reused) and because we cannot cede
425	$cb->(@arg);	534	# 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 {	535	our $unblock_scheduler = async {
		536	$current->desc ("[unblock_sub scheduler]");
434	while () {	537	while () {
435	while (my $cb = pop @unblock_queue) {	538	while (my $cb = pop @unblock_queue) {
		539	# this is an inlined copy of async_pool
436	my $handler = (pop @unblock_pool or new Coro \&unblock_handler_);	540	my $coro = (pop @pool or new Coro \&pool_handler);
437	$handler->{arg} = $cb;	541
		542	$coro->{_invoke} = $cb;
438	$handler->ready;	543	$coro->ready;
439	cede;	544	cede; # for short-lived callbacks, this reduces pressure on the coro pool
440	}	545	}
441		546	schedule; # sleep well
442	schedule;
443	}	547	}
444	};	548	};
445		549
446	sub unblock_sub(&) {	550	sub unblock_sub(&) {
447	my $cb = shift;	551	my $cb = shift;
448		552
449	sub {	553	sub {
450	push @unblock_queue, [$cb, @_];	554	unshift @unblock_queue, [$cb, @_];
451	$unblock_scheduler->ready;	555	$unblock_scheduler->ready;
452	}	556	}
453	}	557	}
454		558
455	=back	559	=back
…		…
462		566
463	- you must make very sure that no coro is still active on global	567	- you must make very sure that no coro is still active on global
464	destruction. very bad things might happen otherwise (usually segfaults).	568	destruction. very bad things might happen otherwise (usually segfaults).
465		569
466	- this module is not thread-safe. You should only ever use this module	570	- 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	571	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	572	to allow per-thread schedulers, but Coro::State does not yet allow
469	this).	573	this).
470		574
471	=head1 SEE ALSO	575	=head1 SEE ALSO
472		576

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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 1.129 by root, Wed Sep 19 22:33:08 2007 UTC

Diff Legend

Comparing Coro/Coro.pm (file contents):
Revision 1.102 by root, Fri Dec 29 11:37:49 2006 UTC vs.
Revision 1.129 by root, Wed Sep 19 22:33:08 2007 UTC