[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 1.121 by root, Fri Apr 13 12:56:55 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 use din this module also
		26	guarentees 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 $VERSION = '3.56';
47		56
48	our @EXPORT = qw(async cede schedule terminate current unblock_sub);	57	our @EXPORT = qw(async async_pool cede schedule terminate current unblock_sub);
49	our %EXPORT_TAGS = (	58	our %EXPORT_TAGS = (
50	prio => [qw(PRIO_MAX PRIO_HIGH PRIO_NORMAL PRIO_LOW PRIO_IDLE PRIO_MIN)],	59	prio => [qw(PRIO_MAX PRIO_HIGH PRIO_NORMAL PRIO_LOW PRIO_IDLE PRIO_MIN)],
51	);	60	);
52	our @EXPORT_OK = @{$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, $ref) = (shift, shift);
67	my @attrs;	76	my @attrs;
…		…
105	C<Coro::current> function instead.	114	C<Coro::current> function instead.
106		115
107	=cut	116	=cut
108		117
109	# maybe some other module used Coro::Specific before...	118	# maybe some other module used Coro::Specific before...
110	if ($current) {
111	$main->{specific} = $current->{specific};	119	$main->{specific} = $current->{specific}
112	}	120	if $current;
113		121
114	$current = $main;	122	_set_current $main;
115		123
116	sub current() { $current }	124	sub current() { $current }
117		125
118	=item $idle	126	=item $idle
119		127
…		…
129	handlers), then it must be prepared to be called recursively.	137	handlers), then it must be prepared to be called recursively.
130		138
131	=cut	139	=cut
132		140
133	$idle = sub {	141	$idle = sub {
134	print STDERR "FATAL: deadlock detected\n";	142	require Carp;
135	exit (51);	143	Carp::croak ("FATAL: deadlock detected");
136	};	144	};
		145
		146	sub _cancel {
		147	my ($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	}
137		157
138	# this coroutine is necessary because a coroutine	158	# this coroutine is necessary because a coroutine
139	# cannot destroy itself.	159	# cannot destroy itself.
140	my @destroy;	160	my @destroy;
		161	my $manager;
		162
141	my $manager; $manager = new Coro sub {	163	$manager = new Coro sub {
142	while () {	164	while () {
143	# by overwriting the state object with the manager we destroy it	165	(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) {	166	while @destroy;
149	my $coro = pop @destroy;
150	$coro->{status} \|\|= [];
151	$_->ready for @{delete $coro->{join} \|\| []};
152		167
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;	168	&schedule;
160	}	169	}
161	};	170	};
		171
		172	$manager->prio (PRIO_MAX);
162		173
163	# static methods. not really.	174	# static methods. not really.
164		175
165	=back	176	=back
166		177
…		…
174		185
175	Create a new asynchronous coroutine and return it's coroutine object	186	Create a new asynchronous coroutine and return it's coroutine object
176	(usually unused). When the sub returns the new coroutine is automatically	187	(usually unused). When the sub returns the new coroutine is automatically
177	terminated.	188	terminated.
178		189
179	Calling C<exit> in a coroutine will not work correctly, so do not do that.	190	Calling C<exit> in a coroutine will try to do the same as calling exit
		191	outside the coroutine, but this is experimental. It is best not to rely on
		192	exit doing any cleanups or even not crashing.
180		193
181	When the coroutine dies, the program will exit, just as in the main	194	When the coroutine dies, the program will exit, just as in the main
182	program.	195	program.
183		196
184	# create a new coroutine that just prints its arguments	197	# create a new coroutine that just prints its arguments
…		…
187	} 1,2,3,4;	200	} 1,2,3,4;
188		201
189	=cut	202	=cut
190		203
191	sub async(&@) {	204	sub async(&@) {
192	my $pid = new Coro @_;	205	my $coro = new Coro @_;
193	$pid->ready;	206	$coro->ready;
194	$pid	207	$coro
		208	}
		209
		210	=item async_pool { ... } [@args...]
		211
		212	Similar to C<async>, but uses a coroutine pool, so you should not call
		213	terminate or join (although you are allowed to), and you get a coroutine
		214	that might have executed other code already (which can be good or bad :).
		215
		216	Also, the block is executed in an C<eval> context and a warning will be
		217	issued in case of an exception instead of terminating the program, as
		218	C<async> does. As the coroutine is being reused, stuff like C<on_destroy>
		219	will not work in the expected way, unless you call terminate or cancel,
		220	which somehow defeats the purpose of pooling.
		221
		222	The priority will be reset to C<0> after each job, otherwise the coroutine
		223	will be re-used "as-is".
		224
		225	The pool size is limited to 8 idle coroutines (this can be adjusted by
		226	changing $Coro::POOL_SIZE), and there can be as many non-idle coros as
		227	required.
		228
		229	If you are concerned about pooled coroutines growing a lot because a
		230	single C<async_pool> used a lot of stackspace you can e.g. C<async_pool {
		231	terminate }> once per second or so to slowly replenish the pool.
		232
		233	=cut
		234
		235	our $POOL_SIZE = 8;
		236	our @pool;
		237
		238	sub pool_handler {
		239	while () {
		240	eval {
		241	my ($cb, @arg) = @{ delete $current->{_invoke} or return };
		242	$cb->(@arg);
		243	};
		244	warn $@ if $@;
		245
		246	last if @pool >= $POOL_SIZE;
		247	push @pool, $current;
		248
		249	$current->save (Coro::State::SAVE_DEF);
		250	$current->prio (0);
		251	schedule;
		252	}
		253	}
		254
		255	sub async_pool(&@) {
		256	# this is also inlined into the unlock_scheduler
		257	my $coro = (pop @pool or new Coro \&pool_handler);
		258
		259	$coro->{_invoke} = [@_];
		260	$coro->ready;
		261
		262	$coro
195	}	263	}
196		264
197	=item schedule	265	=item schedule
198		266
199	Calls the scheduler. Please note that the current coroutine will not be put	267	Calls the scheduler. Please note that the current coroutine will not be put
…		…
224		292
225	"Cede" to other coroutines. This function puts the current coroutine into the	293	"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	294	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.	295	current "timeslice" to other coroutines of the same or higher priority.
228		296
		297	Returns true if at least one coroutine switch has happened.
		298
		299	=item Coro::cede_notself
		300
		301	Works like cede, but is not exported by default and will cede to any
		302	coroutine, regardless of priority, once.
		303
		304	Returns true if at least one coroutine switch has happened.
		305
229	=item terminate [arg...]	306	=item terminate [arg...]
230		307
231	Terminates the current coroutine with the given status values (see L<cancel>).	308	Terminates the current coroutine with the given status values (see L<cancel>).
232		309
233	=cut	310	=cut
…		…
251	Create a new coroutine and return it. When the sub returns the coroutine	328	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	329	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	330	called. To make the coroutine run you must first put it into the ready queue
254	by calling the ready method.	331	by calling the ready method.
255		332
256	Calling C<exit> in a coroutine will not work correctly, so do not do that.	333	See C<async> for additional discussion.
257		334
258	=cut	335	=cut
259		336
260	sub _new_coro {	337	sub _run_coro {
261	terminate &{+shift};	338	terminate &{+shift};
262	}	339	}
263		340
264	sub new {	341	sub new {
265	my $class = shift;	342	my $class = shift;
266		343
267	$class->SUPER::new (\&_new_coro, @_)	344	$class->SUPER::new (\&_run_coro, @_)
268	}	345	}
269		346
270	=item $success = $coroutine->ready	347	=item $success = $coroutine->ready
271		348
272	Put the given coroutine into the ready queue (according to it's priority)	349	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,	355	Return wether the coroutine is currently the ready queue or not,
279		356
280	=item $coroutine->cancel (arg...)	357	=item $coroutine->cancel (arg...)
281		358
282	Terminates the given coroutine and makes it return the given arguments as	359	Terminates the given coroutine and makes it return the given arguments as
283	status (default: the empty list).	360	status (default: the empty list). Never returns if the coroutine is the
		361	current coroutine.
284		362
285	=cut	363	=cut
286		364
287	sub cancel {	365	sub cancel {
288	my $self = shift;	366	my $self = shift;
289	$self->{status} = [@_];	367	$self->{status} = [@_];
		368
		369	if ($current == $self) {
290	push @destroy, $self;	370	push @destroy, $self;
291	$manager->ready;	371	$manager->ready;
292	&schedule if $current == $self;	372	&schedule while 1;
		373	} else {
		374	$self->_cancel;
		375	}
293	}	376	}
294		377
295	=item $coroutine->join	378	=item $coroutine->join
296		379
297	Wait until the coroutine terminates and return any values given to the	380	Wait until the coroutine terminates and return any values given to the
…		…
300		383
301	=cut	384	=cut
302		385
303	sub join {	386	sub join {
304	my $self = shift;	387	my $self = shift;
		388
305	unless ($self->{status}) {	389	unless ($self->{status}) {
306	push @{$self->{join}}, $current;	390	my $current = $current;
307	&schedule;	391
		392	push @{$self->{destroy_cb}}, sub {
		393	$current->ready;
		394	undef $current;
		395	};
		396
		397	&schedule while $current;
308	}	398	}
		399
309	wantarray ? @{$self->{status}} : $self->{status}[0];	400	wantarray ? @{$self->{status}} : $self->{status}[0];
		401	}
		402
		403	=item $coroutine->on_destroy (\&cb)
		404
		405	Registers a callback that is called when this coroutine gets destroyed,
		406	but before it is joined. The callback gets passed the terminate arguments,
		407	if any.
		408
		409	=cut
		410
		411	sub on_destroy {
		412	my ($self, $cb) = @_;
		413
		414	push @{ $self->{destroy_cb} }, $cb;
310	}	415	}
311		416
312	=item $oldprio = $coroutine->prio ($newprio)	417	=item $oldprio = $coroutine->prio ($newprio)
313		418
314	Sets (or gets, if the argument is missing) the priority of the	419	Sets (or gets, if the argument is missing) the priority of the
…		…
349	$old;	454	$old;
350	}	455	}
351		456
352	=back	457	=back
353		458
354	=head2 UTILITY FUNCTIONS	459	=head2 GLOBAL FUNCTIONS
355		460
356	=over 4	461	=over 4
		462
		463	=item Coro::nready
		464
		465	Returns the number of coroutines that are currently in the ready state,
		466	i.e. that can be swicthed to. The value C<0> means that the only runnable
		467	coroutine is the currently running one, so C<cede> would have no effect,
		468	and C<schedule> would cause a deadlock unless there is an idle handler
		469	that wakes up some coroutines.
		470
		471	=item my $guard = Coro::guard { ... }
		472
		473	This creates and returns a guard object. Nothing happens until the object
		474	gets destroyed, in which case the codeblock given as argument will be
		475	executed. This is useful to free locks or other resources in case of a
		476	runtime error or when the coroutine gets canceled, as in both cases the
		477	guard block will be executed. The guard object supports only one method,
		478	C<< ->cancel >>, which will keep the codeblock from being executed.
		479
		480	Example: set some flag and clear it again when the coroutine gets canceled
		481	or the function returns:
		482
		483	sub do_something {
		484	my $guard = Coro::guard { $busy = 0 };
		485	$busy = 1;
		486
		487	# do something that requires $busy to be true
		488	}
		489
		490	=cut
		491
		492	sub guard(&) {
		493	bless \(my $cb = $_[0]), "Coro::guard"
		494	}
		495
		496	sub Coro::guard::cancel {
		497	${$_[0]} = sub { };
		498	}
		499
		500	sub Coro::guard::DESTROY {
		501	${$_[0]}->();
		502	}
		503
357		504
358	=item unblock_sub { ... }	505	=item unblock_sub { ... }
359		506
360	This utility function takes a BLOCK or code reference and "unblocks" it,	507	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	508	returning the new coderef. This means that the new coderef will return
…		…
375	In short: simply use C<unblock_sub { ... }> instead of C<sub { ... }> when	522	In short: simply use C<unblock_sub { ... }> instead of C<sub { ... }> when
376	creating event callbacks that want to block.	523	creating event callbacks that want to block.
377		524
378	=cut	525	=cut
379		526
380	our @unblock_pool;
381	our @unblock_queue;	527	our @unblock_queue;
382	our $UNBLOCK_POOL_SIZE = 2;
383		528
384	sub unblock_handler_ {	529	# we create a special coro because we want to cede,
385	while () {	530	# to reduce pressure on the coro pool (because most callbacks
386	my ($cb, @arg) = @{ delete $Coro::current->{arg} };	531	# return immediately and can be reused) and because we cannot cede
387	$cb->(@arg);	532	# 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 {	533	our $unblock_scheduler = async {
396	while () {	534	while () {
397	while (my $cb = pop @unblock_queue) {	535	while (my $cb = pop @unblock_queue) {
		536	# this is an inlined copy of async_pool
398	my $handler = (pop @unblock_pool or new Coro \&unblock_handler_);	537	my $coro = (pop @pool or new Coro \&pool_handler);
399	$handler->{arg} = $cb;	538
		539	$coro->{_invoke} = $cb;
400	$handler->ready;	540	$coro->ready;
401	cede;	541	cede; # for short-lived callbacks, this reduces pressure on the coro pool
402	}	542	}
403		543	schedule; # sleep well
404	schedule;
405	}	544	}
406	};	545	};
407		546
408	sub unblock_sub(&) {	547	sub unblock_sub(&) {
409	my $cb = shift;	548	my $cb = shift;
410		549
411	sub {	550	sub {
412	push @unblock_queue, [$cb, @_];	551	unshift @unblock_queue, [$cb, @_];
413	$unblock_scheduler->ready;	552	$unblock_scheduler->ready;
414	}	553	}
415	}	554	}
416		555
417	=back	556	=back

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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 1.121 by root, Fri Apr 13 12:56:55 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 1.121 by root, Fri Apr 13 12:56:55 2007 UTC