[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 1.145 by root, Wed Oct 3 16:03:17 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 = '3.3';	55	our $VERSION = '4.0';
56		56
57	our @EXPORT = qw(async cede schedule terminate current unblock_sub);	57	our @EXPORT = qw(async async_pool cede schedule terminate current unblock_sub);
58	our %EXPORT_TAGS = (	58	our %EXPORT_TAGS = (
59	prio => [qw(PRIO_MAX PRIO_HIGH PRIO_NORMAL PRIO_LOW PRIO_IDLE PRIO_MIN)],	59	prio => [qw(PRIO_MAX PRIO_HIGH PRIO_NORMAL PRIO_LOW PRIO_IDLE PRIO_MIN)],
60	);	60	);
61	our @EXPORT_OK = (@{$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, otherwise the coroutine
		225	will be re-used "as-is".
		226
		227	The pool size is limited to 8 idle coroutines (this can be adjusted by
		228	changing $Coro::POOL_SIZE), and there can be as many non-idle coros as
		229	required.
		230
		231	If you are concerned about pooled coroutines growing a lot because a
		232	single C<async_pool> used a lot of stackspace you can e.g. C<async_pool
		233	{ terminate }> once per second or so to slowly replenish the pool. In
		234	addition to that, when the stacks used by a handler grows larger than 16kb
		235	(adjustable with $Coro::POOL_RSS) it will also exit.
		236
		237	=cut
		238
		239	our $POOL_SIZE = 8;
		240	our $POOL_RSS = 16 * 1024;
		241	our @async_pool;
		242
		243	sub pool_handler {
		244	my $cb;
		245
		246	while () {
		247	eval {
		248	while () {
		249	_pool_1 $cb;
		250	&$cb;
		251	_pool_2 $cb;
		252	&schedule;
		253	}
		254	};
		255
		256	last if $@ eq "\3terminate\2\n";
		257	warn $@ if $@;
		258	}
		259	}
		260
		261	sub async_pool(&@) {
		262	# this is also inlined into the unlock_scheduler
		263	my $coro = (pop @async_pool) \|\| new Coro \&pool_handler;
		264
		265	$coro->{_invoke} = [@_];
		266	$coro->ready;
		267
		268	$coro
206	}	269	}
207		270
208	=item schedule	271	=item schedule
209		272
210	Calls the scheduler. Please note that the current coroutine will not be put	273	Calls the scheduler. Please note that the current coroutine will not be put
…		…
223	# wake up sleeping coroutine	286	# wake up sleeping coroutine
224	$current->ready;	287	$current->ready;
225	undef $current;	288	undef $current;
226	};	289	};
227		290
228	# call schedule until event occured.	291	# call schedule until event occurred.
229	# in case we are woken up for other reasons	292	# in case we are woken up for other reasons
230	# (current still defined), loop.	293	# (current still defined), loop.
231	Coro::schedule while $current;	294	Coro::schedule while $current;
232	}	295	}
233		296
…		…
235		298
236	"Cede" to other coroutines. This function puts the current coroutine into the	299	"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	300	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.	301	current "timeslice" to other coroutines of the same or higher priority.
239		302
		303	Returns true if at least one coroutine switch has happened.
		304
240	=item Coro::cede_notself	305	=item Coro::cede_notself
241		306
242	Works like cede, but is not exported by default and will cede to any	307	Works like cede, but is not exported by default and will cede to any
243	coroutine, regardless of priority, once.	308	coroutine, regardless of priority, once.
244		309
		310	Returns true if at least one coroutine switch has happened.
		311
245	=item terminate [arg...]	312	=item terminate [arg...]
246		313
247	Terminates the current coroutine with the given status values (see L<cancel>).	314	Terminates the current coroutine with the given status values (see L<cancel>).
		315
		316	=item killall
		317
		318	Kills/terminates/cancels all coroutines except the currently running
		319	one. This is useful after a fork, either in the child or the parent, as
		320	usually only one of them should inherit the running coroutines.
248		321
249	=cut	322	=cut
250		323
251	sub terminate {	324	sub terminate {
252	$current->cancel (@_);	325	$current->cancel (@_);
		326	}
		327
		328	sub killall {
		329	for (Coro::State::list) {
		330	$_->cancel
		331	if $_ != $current && UNIVERSAL::isa $_, "Coro";
		332	}
253	}	333	}
254		334
255	=back	335	=back
256		336
257	# dynamic methods	337	# dynamic methods
…		…
267	Create a new coroutine and return it. When the sub returns the coroutine	347	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	348	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	349	called. To make the coroutine run you must first put it into the ready queue
270	by calling the ready method.	350	by calling the ready method.
271		351
272	Calling C<exit> in a coroutine will not work correctly, so do not do that.	352	See C<async> and C<Coro::State::new> for additional info about the
		353	coroutine environment.
273		354
274	=cut	355	=cut
275		356
276	sub _run_coro {	357	sub _run_coro {
277	terminate &{+shift};	358	terminate &{+shift};
…		…
294	Return wether the coroutine is currently the ready queue or not,	375	Return wether the coroutine is currently the ready queue or not,
295		376
296	=item $coroutine->cancel (arg...)	377	=item $coroutine->cancel (arg...)
297		378
298	Terminates the given coroutine and makes it return the given arguments as	379	Terminates the given coroutine and makes it return the given arguments as
299	status (default: the empty list).	380	status (default: the empty list). Never returns if the coroutine is the
		381	current coroutine.
300		382
301	=cut	383	=cut
302		384
303	sub cancel {	385	sub cancel {
304	my $self = shift;	386	my $self = shift;
305	$self->{status} = [@_];	387	$self->{_status} = [@_];
		388
		389	if ($current == $self) {
306	push @destroy, $self;	390	push @destroy, $self;
307	$manager->ready;	391	$manager->ready;
308	&schedule if $current == $self;	392	&schedule while 1;
		393	} else {
		394	$self->_cancel;
		395	}
309	}	396	}
310		397
311	=item $coroutine->join	398	=item $coroutine->join
312		399
313	Wait until the coroutine terminates and return any values given to the	400	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	401	C<terminate> or C<cancel> functions. C<join> can be called concurrently
315	from multiple coroutine.	402	from multiple coroutines.
316		403
317	=cut	404	=cut
318		405
319	sub join {	406	sub join {
320	my $self = shift;	407	my $self = shift;
		408
321	unless ($self->{status}) {	409	unless ($self->{_status}) {
322	push @{$self->{join}}, $current;	410	my $current = $current;
323	&schedule;	411
		412	push @{$self->{_on_destroy}}, sub {
		413	$current->ready;
		414	undef $current;
		415	};
		416
		417	&schedule while $current;
324	}	418	}
		419
325	wantarray ? @{$self->{status}} : $self->{status}[0];	420	wantarray ? @{$self->{_status}} : $self->{_status}[0];
326	}	421	}
327		422
328	=item $coroutine->on_destroy (\&cb)	423	=item $coroutine->on_destroy (\&cb)
329		424
330	Registers a callback that is called when this coroutine gets destroyed,	425	Registers a callback that is called when this coroutine gets destroyed,
…		…
334	=cut	429	=cut
335		430
336	sub on_destroy {	431	sub on_destroy {
337	my ($self, $cb) = @_;	432	my ($self, $cb) = @_;
338		433
339	push @{ $self->{destroy_cb} }, $cb;	434	push @{ $self->{_on_destroy} }, $cb;
340	}	435	}
341		436
342	=item $oldprio = $coroutine->prio ($newprio)	437	=item $oldprio = $coroutine->prio ($newprio)
343		438
344	Sets (or gets, if the argument is missing) the priority of the	439	Sets (or gets, if the argument is missing) the priority of the
…		…
369	=item $olddesc = $coroutine->desc ($newdesc)	464	=item $olddesc = $coroutine->desc ($newdesc)
370		465
371	Sets (or gets in case the argument is missing) the description for this	466	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.	467	coroutine. This is just a free-form string you can associate with a coroutine.
373		468
		469	This method simply sets the C<< $coroutine->{desc} >> member to the given string. You
		470	can modify this member directly if you wish.
		471
374	=cut	472	=cut
375		473
376	sub desc {	474	sub desc {
377	my $old = $_[0]{desc};	475	my $old = $_[0]{desc};
378	$_[0]{desc} = $_[1] if @_ > 1;	476	$_[0]{desc} = $_[1] if @_ > 1;
…		…
386	=over 4	484	=over 4
387		485
388	=item Coro::nready	486	=item Coro::nready
389		487
390	Returns the number of coroutines that are currently in the ready state,	488	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	489	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,	490	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	491	and C<schedule> would cause a deadlock unless there is an idle handler
394	that wakes up some coroutines.	492	that wakes up some coroutines.
		493
		494	=item my $guard = Coro::guard { ... }
		495
		496	This creates and returns a guard object. Nothing happens until the object
		497	gets destroyed, in which case the codeblock given as argument will be
		498	executed. This is useful to free locks or other resources in case of a
		499	runtime error or when the coroutine gets canceled, as in both cases the
		500	guard block will be executed. The guard object supports only one method,
		501	C<< ->cancel >>, which will keep the codeblock from being executed.
		502
		503	Example: set some flag and clear it again when the coroutine gets canceled
		504	or the function returns:
		505
		506	sub do_something {
		507	my $guard = Coro::guard { $busy = 0 };
		508	$busy = 1;
		509
		510	# do something that requires $busy to be true
		511	}
		512
		513	=cut
		514
		515	sub guard(&) {
		516	bless \(my $cb = $_[0]), "Coro::guard"
		517	}
		518
		519	sub Coro::guard::cancel {
		520	${$_[0]} = sub { };
		521	}
		522
		523	sub Coro::guard::DESTROY {
		524	${$_[0]}->();
		525	}
		526
395		527
396	=item unblock_sub { ... }	528	=item unblock_sub { ... }
397		529
398	This utility function takes a BLOCK or code reference and "unblocks" it,	530	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	531	returning the new coderef. This means that the new coderef will return
400	immediately without blocking, returning nothing, while the original code	532	immediately without blocking, returning nothing, while the original code
401	ref will be called (with parameters) from within its own coroutine.	533	ref will be called (with parameters) from within its own coroutine.
402		534
403	The reason this fucntion exists is that many event libraries (such as the	535	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	536	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,	537	of thread-safety). This means you must not block within event callbacks,
406	otherwise you might suffer from crashes or worse.	538	otherwise you might suffer from crashes or worse.
407		539
408	This function allows your callbacks to block by executing them in another	540	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	545	In short: simply use C<unblock_sub { ... }> instead of C<sub { ... }> when
414	creating event callbacks that want to block.	546	creating event callbacks that want to block.
415		547
416	=cut	548	=cut
417		549
418	our @unblock_pool;
419	our @unblock_queue;	550	our @unblock_queue;
420	our $UNBLOCK_POOL_SIZE = 2;
421		551
422	sub unblock_handler_ {	552	# we create a special coro because we want to cede,
423	while () {	553	# to reduce pressure on the coro pool (because most callbacks
424	my ($cb, @arg) = @{ delete $Coro::current->{arg} };	554	# return immediately and can be reused) and because we cannot cede
425	$cb->(@arg);	555	# 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 {	556	our $unblock_scheduler = new Coro sub {
434	while () {	557	while () {
435	while (my $cb = pop @unblock_queue) {	558	while (my $cb = pop @unblock_queue) {
436	my $handler = (pop @unblock_pool or new Coro \&unblock_handler_);	559	# this is an inlined copy of async_pool
437	$handler->{arg} = $cb;	560	my $coro = (pop @async_pool) \|\| new Coro \&pool_handler;
		561
		562	$coro->{_invoke} = $cb;
438	$handler->ready;	563	$coro->ready;
439	cede;	564	cede; # for short-lived callbacks, this reduces pressure on the coro pool
440	}	565	}
441		566	schedule; # sleep well
442	schedule;
443	}	567	}
444	};	568	};
		569	$unblock_scheduler->desc ("[unblock_sub scheduler]");
445		570
446	sub unblock_sub(&) {	571	sub unblock_sub(&) {
447	my $cb = shift;	572	my $cb = shift;
448		573
449	sub {	574	sub {
450	push @unblock_queue, [$cb, @_];	575	unshift @unblock_queue, [$cb, @_];
451	$unblock_scheduler->ready;	576	$unblock_scheduler->ready;
452	}	577	}
453	}	578	}
454		579
455	=back	580	=back
…		…
462		587
463	- you must make very sure that no coro is still active on global	588	- you must make very sure that no coro is still active on global
464	destruction. very bad things might happen otherwise (usually segfaults).	589	destruction. very bad things might happen otherwise (usually segfaults).
465		590
466	- this module is not thread-safe. You should only ever use this module	591	- 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	592	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	593	to allow per-thread schedulers, but Coro::State does not yet allow
469	this).	594	this).
470		595
471	=head1 SEE ALSO	596	=head1 SEE ALSO
472		597

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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 1.145 by root, Wed Oct 3 16:03:17 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 1.145 by root, Wed Oct 3 16:03:17 2007 UTC