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

Comparing Coro/Coro.pm (file contents):
Revision 1.92 by root, Fri Dec 1 03:47:55 2006 UTC vs.
Revision 1.132 by root, Thu Sep 20 22:53:23 2007 UTC

…		…
18		18
19	cede;	19	cede;
20		20
21	=head1 DESCRIPTION	21	=head1 DESCRIPTION
22		22
23	This module collection manages coroutines. Coroutines are similar to	23	This module collection manages coroutines. Coroutines are similar
24	threads but don't run in parallel.	24	to threads but don't run in parallel at the same time even on SMP
		25	machines. The specific flavor of coroutine used in this module also
		26	guarantees you that it will not switch between coroutines unless
		27	necessary, at easily-identified points in your program, so locking and
		28	parallel access are rarely an issue, making coroutine programming much
		29	safer than threads programming.
25		30
		31	(Perl, however, does not natively support real threads but instead does a
		32	very slow and memory-intensive emulation of processes using threads. This
		33	is a performance win on Windows machines, and a loss everywhere else).
		34
26	In this module, coroutines are defined as "callchain + lexical variables	35	In this module, coroutines are defined as "callchain + lexical variables +
27	+ @_ + $_ + $@ + $^W + C stack), that is, a coroutine has it's own	36	@_ + $_ + $@ + $/ + C stack), that is, a coroutine has its own callchain,
28	callchain, it's own set of lexicals and it's own set of perl's most	37	its own set of lexicals and its own set of perls most important global
29	important global variables.	38	variables.
30		39
31	=cut	40	=cut
32		41
33	package Coro;	42	package Coro;
34		43
…		…
41		50
42	our $idle; # idle handler	51	our $idle; # idle handler
43	our $main; # main coroutine	52	our $main; # main coroutine
44	our $current; # current coroutine	53	our $current; # current coroutine
45		54
46	our $VERSION = '3.0';	55	our $VERSION = '3.7';
47		56
48	our @EXPORT = qw(async cede schedule terminate current unblock_sub);	57	our @EXPORT = qw(async async_pool cede schedule terminate current unblock_sub);
49	our %EXPORT_TAGS = (	58	our %EXPORT_TAGS = (
50	prio => [qw(PRIO_MAX PRIO_HIGH PRIO_NORMAL PRIO_LOW PRIO_IDLE PRIO_MIN)],	59	prio => [qw(PRIO_MAX PRIO_HIGH PRIO_NORMAL PRIO_LOW PRIO_IDLE PRIO_MIN)],
51	);	60	);
52	our @EXPORT_OK = @{$EXPORT_TAGS{prio}};	61	our @EXPORT_OK = (@{$EXPORT_TAGS{prio}}, qw(nready));
53		62
54	{	63	{
55	my @async;	64	my @async;
56	my $init;	65	my $init;
57		66
58	# this way of handling attributes simply is NOT scalable ;()	67	# this way of handling attributes simply is NOT scalable ;()
59	sub import {	68	sub import {
60	no strict 'refs';	69	no strict 'refs';
61		70
62	Coro->export_to_level(1, @_);	71	Coro->export_to_level (1, @_);
63		72
64	my $old = *{(caller)[0]."::MODIFY_CODE_ATTRIBUTES"}{CODE};	73	my $old = *{(caller)[0]."::MODIFY_CODE_ATTRIBUTES"}{CODE};
65	*{(caller)[0]."::MODIFY_CODE_ATTRIBUTES"} = sub {	74	*{(caller)[0]."::MODIFY_CODE_ATTRIBUTES"} = sub {
66	my ($package, $ref) = (shift, shift);	75	my ($package, $ref) = (shift, shift);
67	my @attrs;	76	my @attrs;
…		…
99		108
100	The current coroutine (the last coroutine switched to). The initial value	109	The current coroutine (the last coroutine switched to). The initial value
101	is C<$main> (of course).	110	is C<$main> (of course).
102		111
103	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
104	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
105	C<Coro::current> function instead.	114	C<Coro::current> function instead.
106		115
107	=cut	116	=cut
108		117
		118	$main->{desc} = "[main::]";
		119
109	# maybe some other module used Coro::Specific before...	120	# maybe some other module used Coro::Specific before...
110	if ($current) {
111	$main->{specific} = $current->{specific};	121	$main->{specific} = $current->{specific}
112	}	122	if $current;
113		123
114	$current = $main;	124	_set_current $main;
115		125
116	sub current() { $current }	126	sub current() { $current }
117		127
118	=item $idle	128	=item $idle
119		129
…		…
129	handlers), then it must be prepared to be called recursively.	139	handlers), then it must be prepared to be called recursively.
130		140
131	=cut	141	=cut
132		142
133	$idle = sub {	143	$idle = sub {
134	print STDERR "FATAL: deadlock detected\n";	144	require Carp;
135	exit (51);	145	Carp::croak ("FATAL: deadlock detected");
136	};	146	};
		147
		148	sub _cancel {
		149	my ($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	}
137		159
138	# this coroutine is necessary because a coroutine	160	# this coroutine is necessary because a coroutine
139	# cannot destroy itself.	161	# cannot destroy itself.
140	my @destroy;	162	my @destroy;
		163	my $manager;
		164
141	my $manager; $manager = new Coro sub {	165	$manager = new Coro sub {
142	while () {	166	while () {
143	# by overwriting the state object with the manager we destroy it	167	(shift @destroy)->_cancel
144	# while still being able to schedule this coroutine (in case it has
145	# been readied multiple times. this is harmless since the manager
146	# can be called as many times as neccessary and will always
147	# remove itself from the runqueue
148	while (@destroy) {	168	while @destroy;
149	my $coro = pop @destroy;
150	$coro->{status} \|\|= [];
151	$_->ready for @{delete $coro->{join} \|\| []};
152		169
153	# the next line destroys the coro state, but keeps the
154	# coroutine itself intact (we basically make it a zombie
155	# coroutine that always runs the manager thread, so it's possible
156	# to transfer() to this coroutine).
157	$coro->_clone_state_from ($manager);
158	}
159	&schedule;	170	&schedule;
160	}	171	}
161	};	172	};
		173	$manager->desc ("[coro manager]");
		174	$manager->prio (PRIO_MAX);
162		175
163	# static methods. not really.	176	# static methods. not really.
164		177
165	=back	178	=back
166		179
…		…
174		187
175	Create a new asynchronous coroutine and return it's coroutine object	188	Create a new asynchronous coroutine and return it's coroutine object
176	(usually unused). When the sub returns the new coroutine is automatically	189	(usually unused). When the sub returns the new coroutine is automatically
177	terminated.	190	terminated.
178		191
179	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
180		193	the coroutine. Likewise, when the coroutine dies, the program will exit,
181	When the coroutine dies, the program will exit, just as in the main	194	just as it would in the main program.
182	program.
183		195
184	# create a new coroutine that just prints its arguments	196	# create a new coroutine that just prints its arguments
185	async {	197	async {
186	print "@_\n";	198	print "@_\n";
187	} 1,2,3,4;	199	} 1,2,3,4;
188		200
189	=cut	201	=cut
190		202
191	sub async(&@) {	203	sub async(&@) {
192	my $pid = new Coro @_;	204	my $coro = new Coro @_;
193	$pid->ready;	205	$coro->ready;
194	$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 $MAX_POOL_RSS = 64 * 1024;
		236	our @pool;
		237
		238	sub pool_handler {
		239	while () {
		240	$current->{desc} = "[async_pool]";
		241
		242	eval {
		243	my ($cb, @arg) = @{ delete $current->{_invoke} or return };
		244	$cb->(@arg);
		245	};
		246	warn $@ if $@;
		247
		248	last if @pool >= $POOL_SIZE \|\| $current->rss >= $MAX_POOL_RSS;
		249
		250	push @pool, $current;
		251	$current->{desc} = "[async_pool idle]";
		252	$current->save (Coro::State::SAVE_DEF);
		253	$current->prio (0);
		254	schedule;
		255	}
		256	}
		257
		258	sub async_pool(&@) {
		259	# this is also inlined into the unlock_scheduler
		260	my $coro = (pop @pool) \|\| new Coro \&pool_handler;;
		261
		262	$coro->{_invoke} = [@_];
		263	$coro->ready;
		264
		265	$coro
195	}	266	}
196		267
197	=item schedule	268	=item schedule
198		269
199	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
…		…
212	# wake up sleeping coroutine	283	# wake up sleeping coroutine
213	$current->ready;	284	$current->ready;
214	undef $current;	285	undef $current;
215	};	286	};
216		287
217	# call schedule until event occured.	288	# call schedule until event occurred.
218	# in case we are woken up for other reasons	289	# in case we are woken up for other reasons
219	# (current still defined), loop.	290	# (current still defined), loop.
220	Coro::schedule while $current;	291	Coro::schedule while $current;
221	}	292	}
222		293
223	=item cede	294	=item cede
224		295
225	"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
226	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
227	current "timeslice" to other coroutines of the same or higher priority.	298	current "timeslice" to other coroutines of the same or higher priority.
		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.
228		308
229	=item terminate [arg...]	309	=item terminate [arg...]
230		310
231	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>).
232		312
…		…
251	Create a new coroutine and return it. When the sub returns the coroutine	331	Create a new coroutine and return it. When the sub returns the coroutine
252	automatically terminates as if C<terminate> with the returned values were	332	automatically terminates as if C<terminate> with the returned values were
253	called. To make the coroutine run you must first put it into the ready queue	333	called. To make the coroutine run you must first put it into the ready queue
254	by calling the ready method.	334	by calling the ready method.
255		335
256	Calling C<exit> in a coroutine will not work correctly, so do not do that.	336	See C<async> for additional discussion.
257		337
258	=cut	338	=cut
259		339
260	sub _new_coro {	340	sub _run_coro {
261	terminate &{+shift};	341	terminate &{+shift};
262	}	342	}
263		343
264	sub new {	344	sub new {
265	my $class = shift;	345	my $class = shift;
266		346
267	$class->SUPER::new (\&_new_coro, @_)	347	$class->SUPER::new (\&_run_coro, @_)
268	}	348	}
269		349
270	=item $success = $coroutine->ready	350	=item $success = $coroutine->ready
271		351
272	Put the given coroutine into the ready queue (according to it's priority)	352	Put the given coroutine into the ready queue (according to it's priority)
…		…
278	Return wether the coroutine is currently the ready queue or not,	358	Return wether the coroutine is currently the ready queue or not,
279		359
280	=item $coroutine->cancel (arg...)	360	=item $coroutine->cancel (arg...)
281		361
282	Terminates the given coroutine and makes it return the given arguments as	362	Terminates the given coroutine and makes it return the given arguments as
283	status (default: the empty list).	363	status (default: the empty list). Never returns if the coroutine is the
		364	current coroutine.
284		365
285	=cut	366	=cut
286		367
287	sub cancel {	368	sub cancel {
288	my $self = shift;	369	my $self = shift;
289	$self->{status} = [@_];	370	$self->{status} = [@_];
		371
		372	if ($current == $self) {
290	push @destroy, $self;	373	push @destroy, $self;
291	$manager->ready;	374	$manager->ready;
292	&schedule if $current == $self;	375	&schedule while 1;
		376	} else {
		377	$self->_cancel;
		378	}
293	}	379	}
294		380
295	=item $coroutine->join	381	=item $coroutine->join
296		382
297	Wait until the coroutine terminates and return any values given to the	383	Wait until the coroutine terminates and return any values given to the
…		…
300		386
301	=cut	387	=cut
302		388
303	sub join {	389	sub join {
304	my $self = shift;	390	my $self = shift;
		391
305	unless ($self->{status}) {	392	unless ($self->{status}) {
306	push @{$self->{join}}, $current;	393	my $current = $current;
307	&schedule;	394
		395	push @{$self->{destroy_cb}}, sub {
		396	$current->ready;
		397	undef $current;
		398	};
		399
		400	&schedule while $current;
308	}	401	}
		402
309	wantarray ? @{$self->{status}} : $self->{status}[0];	403	wantarray ? @{$self->{status}} : $self->{status}[0];
		404	}
		405
		406	=item $coroutine->on_destroy (\&cb)
		407
		408	Registers a callback that is called when this coroutine gets destroyed,
		409	but before it is joined. The callback gets passed the terminate arguments,
		410	if any.
		411
		412	=cut
		413
		414	sub on_destroy {
		415	my ($self, $cb) = @_;
		416
		417	push @{ $self->{destroy_cb} }, $cb;
310	}	418	}
311		419
312	=item $oldprio = $coroutine->prio ($newprio)	420	=item $oldprio = $coroutine->prio ($newprio)
313		421
314	Sets (or gets, if the argument is missing) the priority of the	422	Sets (or gets, if the argument is missing) the priority of the
…		…
349	$old;	457	$old;
350	}	458	}
351		459
352	=back	460	=back
353		461
354	=head2 UTILITY FUNCTIONS	462	=head2 GLOBAL FUNCTIONS
355		463
356	=over 4	464	=over 4
		465
		466	=item Coro::nready
		467
		468	Returns the number of coroutines that are currently in the ready state,
		469	i.e. that can be switched to. The value C<0> means that the only runnable
		470	coroutine is the currently running one, so C<cede> would have no effect,
		471	and C<schedule> would cause a deadlock unless there is an idle handler
		472	that wakes up some coroutines.
		473
		474	=item my $guard = Coro::guard { ... }
		475
		476	This creates and returns a guard object. Nothing happens until the object
		477	gets destroyed, in which case the codeblock given as argument will be
		478	executed. This is useful to free locks or other resources in case of a
		479	runtime error or when the coroutine gets canceled, as in both cases the
		480	guard block will be executed. The guard object supports only one method,
		481	C<< ->cancel >>, which will keep the codeblock from being executed.
		482
		483	Example: set some flag and clear it again when the coroutine gets canceled
		484	or the function returns:
		485
		486	sub do_something {
		487	my $guard = Coro::guard { $busy = 0 };
		488	$busy = 1;
		489
		490	# do something that requires $busy to be true
		491	}
		492
		493	=cut
		494
		495	sub guard(&) {
		496	bless \(my $cb = $_[0]), "Coro::guard"
		497	}
		498
		499	sub Coro::guard::cancel {
		500	${$_[0]} = sub { };
		501	}
		502
		503	sub Coro::guard::DESTROY {
		504	${$_[0]}->();
		505	}
		506
357		507
358	=item unblock_sub { ... }	508	=item unblock_sub { ... }
359		509
360	This utility function takes a BLOCK or code reference and "unblocks" it,	510	This utility function takes a BLOCK or code reference and "unblocks" it,
361	returning the new coderef. This means that the new coderef will return	511	returning the new coderef. This means that the new coderef will return
362	immediately without blocking, returning nothing, while the original code	512	immediately without blocking, returning nothing, while the original code
363	ref will be called (with parameters) from within its own coroutine.	513	ref will be called (with parameters) from within its own coroutine.
364		514
365	The reason this fucntion exists is that many event libraries (such as the	515	The reason this function exists is that many event libraries (such as the
366	venerable L<Event\|Event> module) are not coroutine-safe (a weaker form	516	venerable L<Event\|Event> module) are not coroutine-safe (a weaker form
367	of thread-safety). This means you must not block within event callbacks,	517	of thread-safety). This means you must not block within event callbacks,
368	otherwise you might suffer from crashes or worse.	518	otherwise you might suffer from crashes or worse.
369		519
370	This function allows your callbacks to block by executing them in another	520	This function allows your callbacks to block by executing them in another
…		…
375	In short: simply use C<unblock_sub { ... }> instead of C<sub { ... }> when	525	In short: simply use C<unblock_sub { ... }> instead of C<sub { ... }> when
376	creating event callbacks that want to block.	526	creating event callbacks that want to block.
377		527
378	=cut	528	=cut
379		529
380	our @unblock_pool;
381	our @unblock_queue;	530	our @unblock_queue;
382	our $UNBLOCK_POOL_SIZE = 2;
383		531
384	sub unblock_handler_ {	532	# we create a special coro because we want to cede,
385	while () {	533	# to reduce pressure on the coro pool (because most callbacks
386	my ($cb, @arg) = @{ delete $Coro::current->{arg} };	534	# return immediately and can be reused) and because we cannot cede
387	$cb->(@arg);	535	# inside an event callback.
388
389	last if @unblock_pool >= $UNBLOCK_POOL_SIZE;
390	push @unblock_pool, $Coro::current;
391	schedule;
392	}
393	}
394
395	our $unblock_scheduler = async {	536	our $unblock_scheduler = new Coro sub {
396	while () {	537	while () {
397	while (my $cb = pop @unblock_queue) {	538	while (my $cb = pop @unblock_queue) {
		539	# this is an inlined copy of async_pool
398	my $handler = (pop @unblock_pool or new Coro \&unblock_handler_);	540	my $coro = (pop @pool or new Coro \&pool_handler);
399	$handler->{arg} = $cb;	541
		542	$coro->{_invoke} = $cb;
400	$handler->ready;	543	$coro->ready;
401	cede;	544	cede; # for short-lived callbacks, this reduces pressure on the coro pool
402	}	545	}
403		546	schedule; # sleep well
404	schedule;
405	}	547	}
406	};	548	};
		549	$unblock_scheduler->desc ("[unblock_sub scheduler]");
407		550
408	sub unblock_sub(&) {	551	sub unblock_sub(&) {
409	my $cb = shift;	552	my $cb = shift;
410		553
411	sub {	554	sub {
412	push @unblock_queue, [$cb, @_];	555	unshift @unblock_queue, [$cb, @_];
413	$unblock_scheduler->ready;	556	$unblock_scheduler->ready;
414	}	557	}
415	}	558	}
416		559
417	=back	560	=back
…		…
424		567
425	- you must make very sure that no coro is still active on global	568	- you must make very sure that no coro is still active on global
426	destruction. very bad things might happen otherwise (usually segfaults).	569	destruction. very bad things might happen otherwise (usually segfaults).
427		570
428	- this module is not thread-safe. You should only ever use this module	571	- this module is not thread-safe. You should only ever use this module
429	from the same thread (this requirement might be losened in the future	572	from the same thread (this requirement might be loosened in the future
430	to allow per-thread schedulers, but Coro::State does not yet allow	573	to allow per-thread schedulers, but Coro::State does not yet allow
431	this).	574	this).
432		575
433	=head1 SEE ALSO	576	=head1 SEE ALSO
434		577

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Comparing Coro/Coro.pm (file contents): Revision 1.92 by root, Fri Dec 1 03:47:55 2006 UTC vs. Revision 1.132 by root, Thu Sep 20 22:53:23 2007 UTC

Diff Legend

Comparing Coro/Coro.pm (file contents):
Revision 1.92 by root, Fri Dec 1 03:47:55 2006 UTC vs.
Revision 1.132 by root, Thu Sep 20 22:53:23 2007 UTC