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

Comparing Coro/Coro.pm (file contents):
Revision 1.101 by root, Fri Dec 29 08:36:34 2006 UTC vs.
Revision 1.142 by root, Tue Oct 2 23:16:24 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 $VERSION = '3.8';
56		56
57	our @EXPORT = qw(async cede schedule terminate current unblock_sub);	57	our @EXPORT = qw(async async_pool cede schedule terminate current unblock_sub);
58	our %EXPORT_TAGS = (	58	our %EXPORT_TAGS = (
59	prio => [qw(PRIO_MAX PRIO_HIGH PRIO_NORMAL PRIO_LOW PRIO_IDLE PRIO_MIN)],	59	prio => [qw(PRIO_MAX PRIO_HIGH PRIO_NORMAL PRIO_LOW PRIO_IDLE PRIO_MIN)],
60	);	60	);
61	our @EXPORT_OK = (@{$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		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	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. 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
206	}	266	}
207		267
208	=item schedule	268	=item schedule
209		269
210	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
…		…
223	# wake up sleeping coroutine	283	# wake up sleeping coroutine
224	$current->ready;	284	$current->ready;
225	undef $current;	285	undef $current;
226	};	286	};
227		287
228	# call schedule until event occured.	288	# call schedule until event occurred.
229	# in case we are woken up for other reasons	289	# in case we are woken up for other reasons
230	# (current still defined), loop.	290	# (current still defined), loop.
231	Coro::schedule while $current;	291	Coro::schedule while $current;
232	}	292	}
233		293
…		…
235		295
236	"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
237	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
238	current "timeslice" to other coroutines of the same or higher priority.	298	current "timeslice" to other coroutines of the same or higher priority.
239		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
240	=item terminate [arg...]	309	=item terminate [arg...]
241		310
242	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.
243		318
244	=cut	319	=cut
245		320
246	sub terminate {	321	sub terminate {
247	$current->cancel (@_);	322	$current->cancel (@_);
		323	}
		324
		325	sub killall {
		326	for (Coro::State::list) {
		327	$_->cancel
		328	if $_ != $current && UNIVERSAL::isa $_, "Coro";
		329	}
248	}	330	}
249		331
250	=back	332	=back
251		333
252	# dynamic methods	334	# dynamic methods
…		…
262	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
263	automatically terminates as if C<terminate> with the returned values were	345	automatically terminates as if C<terminate> with the returned values were
264	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
265	by calling the ready method.	347	by calling the ready method.
266		348
267	Calling C<exit> in a coroutine will not work correctly, so do not do that.	349	See C<async> for additional discussion.
268		350
269	=cut	351	=cut
270		352
271	sub _run_coro {	353	sub _run_coro {
272	terminate &{+shift};	354	terminate &{+shift};
…		…
289	Return wether the coroutine is currently the ready queue or not,	371	Return wether the coroutine is currently the ready queue or not,
290		372
291	=item $coroutine->cancel (arg...)	373	=item $coroutine->cancel (arg...)
292		374
293	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
294	status (default: the empty list).	376	status (default: the empty list). Never returns if the coroutine is the
		377	current coroutine.
295		378
296	=cut	379	=cut
297		380
298	sub cancel {	381	sub cancel {
299	my $self = shift;	382	my $self = shift;
300	$self->{status} = [@_];	383	$self->{_status} = [@_];
		384
		385	if ($current == $self) {
301	push @destroy, $self;	386	push @destroy, $self;
302	$manager->ready;	387	$manager->ready;
303	&schedule if $current == $self;	388	&schedule while 1;
		389	} else {
		390	$self->_cancel;
		391	}
304	}	392	}
305		393
306	=item $coroutine->join	394	=item $coroutine->join
307		395
308	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
…		…
311		399
312	=cut	400	=cut
313		401
314	sub join {	402	sub join {
315	my $self = shift;	403	my $self = shift;
		404
316	unless ($self->{status}) {	405	unless ($self->{_status}) {
317	push @{$self->{join}}, $current;	406	my $current = $current;
318	&schedule;	407
		408	push @{$self->{_on_destroy}}, sub {
		409	$current->ready;
		410	undef $current;
		411	};
		412
		413	&schedule while $current;
319	}	414	}
		415
320	wantarray ? @{$self->{status}} : $self->{status}[0];	416	wantarray ? @{$self->{_status}} : $self->{_status}[0];
321	}	417	}
322		418
323	=item $coroutine->on_destroy (\&cb)	419	=item $coroutine->on_destroy (\&cb)
324		420
325	Registers a callback that is called when this coroutine gets destroyed,	421	Registers a callback that is called when this coroutine gets destroyed,
…		…
329	=cut	425	=cut
330		426
331	sub on_destroy {	427	sub on_destroy {
332	my ($self, $cb) = @_;	428	my ($self, $cb) = @_;
333		429
334	push @{ $self->{destroy_cb} }, $cb;	430	push @{ $self->{_on_destroy} }, $cb;
335	}	431	}
336		432
337	=item $oldprio = $coroutine->prio ($newprio)	433	=item $oldprio = $coroutine->prio ($newprio)
338		434
339	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	=item $olddesc = $coroutine->desc ($newdesc)	460	=item $olddesc = $coroutine->desc ($newdesc)
365		461
366	Sets (or gets in case the argument is missing) the description for this	462	Sets (or gets in case the argument is missing) the description for this
367	coroutine. This is just a free-form string you can associate with a coroutine.	463	coroutine. This is just a free-form string you can associate with a coroutine.
368		464
		465	This method simply sets the C<< $coroutine->{desc} >> member to the given string. You
		466	can modify this member directly if you wish.
		467
369	=cut	468	=cut
370		469
371	sub desc {	470	sub desc {
372	my $old = $_[0]{desc};	471	my $old = $_[0]{desc};
373	$_[0]{desc} = $_[1] if @_ > 1;	472	$_[0]{desc} = $_[1] if @_ > 1;
…		…
381	=over 4	480	=over 4
382		481
383	=item Coro::nready	482	=item Coro::nready
384		483
385	Returns the number of coroutines that are currently in the ready state,	484	Returns the number of coroutines that are currently in the ready state,
386	i.e. that can be swicthed to. The value C<0> means that the only runnable	485	i.e. that can be switched to. The value C<0> means that the only runnable
387	coroutine is the currently running one, so C<cede> would have no effect,	486	coroutine is the currently running one, so C<cede> would have no effect,
388	and C<schedule> would cause a deadlock unless there is an idle handler	487	and C<schedule> would cause a deadlock unless there is an idle handler
389	that wakes up some coroutines.	488	that wakes up some coroutines.
		489
		490	=item my $guard = Coro::guard { ... }
		491
		492	This creates and returns a guard object. Nothing happens until the object
		493	gets destroyed, in which case the codeblock given as argument will be
		494	executed. This is useful to free locks or other resources in case of a
		495	runtime error or when the coroutine gets canceled, as in both cases the
		496	guard block will be executed. The guard object supports only one method,
		497	C<< ->cancel >>, which will keep the codeblock from being executed.
		498
		499	Example: set some flag and clear it again when the coroutine gets canceled
		500	or the function returns:
		501
		502	sub do_something {
		503	my $guard = Coro::guard { $busy = 0 };
		504	$busy = 1;
		505
		506	# do something that requires $busy to be true
		507	}
		508
		509	=cut
		510
		511	sub guard(&) {
		512	bless \(my $cb = $_[0]), "Coro::guard"
		513	}
		514
		515	sub Coro::guard::cancel {
		516	${$_[0]} = sub { };
		517	}
		518
		519	sub Coro::guard::DESTROY {
		520	${$_[0]}->();
		521	}
		522
390		523
391	=item unblock_sub { ... }	524	=item unblock_sub { ... }
392		525
393	This utility function takes a BLOCK or code reference and "unblocks" it,	526	This utility function takes a BLOCK or code reference and "unblocks" it,
394	returning the new coderef. This means that the new coderef will return	527	returning the new coderef. This means that the new coderef will return
395	immediately without blocking, returning nothing, while the original code	528	immediately without blocking, returning nothing, while the original code
396	ref will be called (with parameters) from within its own coroutine.	529	ref will be called (with parameters) from within its own coroutine.
397		530
398	The reason this fucntion exists is that many event libraries (such as the	531	The reason this function exists is that many event libraries (such as the
399	venerable L<Event\|Event> module) are not coroutine-safe (a weaker form	532	venerable L<Event\|Event> module) are not coroutine-safe (a weaker form
400	of thread-safety). This means you must not block within event callbacks,	533	of thread-safety). This means you must not block within event callbacks,
401	otherwise you might suffer from crashes or worse.	534	otherwise you might suffer from crashes or worse.
402		535
403	This function allows your callbacks to block by executing them in another	536	This function allows your callbacks to block by executing them in another
…		…
408	In short: simply use C<unblock_sub { ... }> instead of C<sub { ... }> when	541	In short: simply use C<unblock_sub { ... }> instead of C<sub { ... }> when
409	creating event callbacks that want to block.	542	creating event callbacks that want to block.
410		543
411	=cut	544	=cut
412		545
413	our @unblock_pool;
414	our @unblock_queue;	546	our @unblock_queue;
415	our $UNBLOCK_POOL_SIZE = 2;
416		547
417	sub unblock_handler_ {	548	# we create a special coro because we want to cede,
418	while () {	549	# to reduce pressure on the coro pool (because most callbacks
419	my ($cb, @arg) = @{ delete $Coro::current->{arg} };	550	# return immediately and can be reused) and because we cannot cede
420	$cb->(@arg);	551	# inside an event callback.
421
422	last if @unblock_pool >= $UNBLOCK_POOL_SIZE;
423	push @unblock_pool, $Coro::current;
424	schedule;
425	}
426	}
427
428	our $unblock_scheduler = async {	552	our $unblock_scheduler = new Coro sub {
429	while () {	553	while () {
430	while (my $cb = pop @unblock_queue) {	554	while (my $cb = pop @unblock_queue) {
431	my $handler = (pop @unblock_pool or new Coro \&unblock_handler_);	555	# this is an inlined copy of async_pool
432	$handler->{arg} = $cb;	556	my $coro = (pop @async_pool) \|\| new Coro \&pool_handler;
		557
		558	$coro->{_invoke} = $cb;
433	$handler->ready;	559	$coro->ready;
434	cede;	560	cede; # for short-lived callbacks, this reduces pressure on the coro pool
435	}	561	}
436		562	schedule; # sleep well
437	schedule;
438	}	563	}
439	};	564	};
		565	$unblock_scheduler->desc ("[unblock_sub scheduler]");
440		566
441	sub unblock_sub(&) {	567	sub unblock_sub(&) {
442	my $cb = shift;	568	my $cb = shift;
443		569
444	sub {	570	sub {
445	push @unblock_queue, [$cb, @_];	571	unshift @unblock_queue, [$cb, @_];
446	$unblock_scheduler->ready;	572	$unblock_scheduler->ready;
447	}	573	}
448	}	574	}
449		575
450	=back	576	=back
…		…
457		583
458	- you must make very sure that no coro is still active on global	584	- you must make very sure that no coro is still active on global
459	destruction. very bad things might happen otherwise (usually segfaults).	585	destruction. very bad things might happen otherwise (usually segfaults).
460		586
461	- this module is not thread-safe. You should only ever use this module	587	- this module is not thread-safe. You should only ever use this module
462	from the same thread (this requirement might be losened in the future	588	from the same thread (this requirement might be loosened in the future
463	to allow per-thread schedulers, but Coro::State does not yet allow	589	to allow per-thread schedulers, but Coro::State does not yet allow
464	this).	590	this).
465		591
466	=head1 SEE ALSO	592	=head1 SEE ALSO
467		593

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Comparing Coro/Coro.pm (file contents): Revision 1.101 by root, Fri Dec 29 08:36:34 2006 UTC vs. Revision 1.142 by root, Tue Oct 2 23:16:24 2007 UTC

Diff Legend

Comparing Coro/Coro.pm (file contents):
Revision 1.101 by root, Fri Dec 29 08:36:34 2006 UTC vs.
Revision 1.142 by root, Tue Oct 2 23:16:24 2007 UTC