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

Comparing Coro/Coro.pm (file contents):
Revision 1.96 by root, Mon Dec 4 03:48:16 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 = '3.01';	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
…		…
132	$idle = sub {	141	$idle = sub {
133	require Carp;	142	require Carp;
134	Carp::croak ("FATAL: deadlock detected");	143	Carp::croak ("FATAL: deadlock detected");
135	};	144	};
136		145
		146	sub _cancel {
		147	my ($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
137	# this coroutine is necessary because a coroutine	158	# this coroutine is necessary because a coroutine
138	# cannot destroy itself.	159	# cannot destroy itself.
139	my @destroy;	160	my @destroy;
		161	my $manager;
		162
140	my $manager; $manager = new Coro sub {	163	$manager = new Coro sub {
141	while () {	164	while () {
142	# by overwriting the state object with the manager we destroy it	165	(shift @destroy)->_cancel
143	# while still being able to schedule this coroutine (in case it has
144	# been readied multiple times. this is harmless since the manager
145	# can be called as many times as neccessary and will always
146	# remove itself from the runqueue
147	while (@destroy) {	166	while @destroy;
148	my $coro = pop @destroy;
149	$coro->{status} \|\|= [];
150	$_->ready for @{delete $coro->{join} \|\| []};
151		167
152	# the next line destroys the coro state, but keeps the
153	# coroutine itself intact (we basically make it a zombie
154	# coroutine that always runs the manager thread, so it's possible
155	# to transfer() to this coroutine).
156	$coro->_clone_state_from ($manager);
157	}
158	&schedule;	168	&schedule;
159	}	169	}
160	};	170	};
		171
		172	$manager->prio (PRIO_MAX);
161		173
162	# static methods. not really.	174	# static methods. not really.
163		175
164	=back	176	=back
165		177
…		…
173		185
174	Create a new asynchronous coroutine and return it's coroutine object	186	Create a new asynchronous coroutine and return it's coroutine object
175	(usually unused). When the sub returns the new coroutine is automatically	187	(usually unused). When the sub returns the new coroutine is automatically
176	terminated.	188	terminated.
177		189
178	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.
179		193
180	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
181	program.	195	program.
182		196
183	# create a new coroutine that just prints its arguments	197	# create a new coroutine that just prints its arguments
…		…
186	} 1,2,3,4;	200	} 1,2,3,4;
187		201
188	=cut	202	=cut
189		203
190	sub async(&@) {	204	sub async(&@) {
191	my $pid = new Coro @_;	205	my $coro = new Coro @_;
192	$pid->ready;	206	$coro->ready;
193	$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
194	}	263	}
195		264
196	=item schedule	265	=item schedule
197		266
198	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
…		…
223		292
224	"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
225	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
226	current "timeslice" to other coroutines of the same or higher priority.	295	current "timeslice" to other coroutines of the same or higher priority.
227		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
228	=item terminate [arg...]	306	=item terminate [arg...]
229		307
230	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>).
231		309
232	=cut	310	=cut
…		…
250	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
251	automatically terminates as if C<terminate> with the returned values were	329	automatically terminates as if C<terminate> with the returned values were
252	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
253	by calling the ready method.	331	by calling the ready method.
254		332
255	Calling C<exit> in a coroutine will not work correctly, so do not do that.	333	See C<async> for additional discussion.
256		334
257	=cut	335	=cut
258		336
259	sub _run_coro {	337	sub _run_coro {
260	terminate &{+shift};	338	terminate &{+shift};
…		…
277	Return wether the coroutine is currently the ready queue or not,	355	Return wether the coroutine is currently the ready queue or not,
278		356
279	=item $coroutine->cancel (arg...)	357	=item $coroutine->cancel (arg...)
280		358
281	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
282	status (default: the empty list).	360	status (default: the empty list). Never returns if the coroutine is the
		361	current coroutine.
283		362
284	=cut	363	=cut
285		364
286	sub cancel {	365	sub cancel {
287	my $self = shift;	366	my $self = shift;
288	$self->{status} = [@_];	367	$self->{status} = [@_];
		368
		369	if ($current == $self) {
289	push @destroy, $self;	370	push @destroy, $self;
290	$manager->ready;	371	$manager->ready;
291	&schedule if $current == $self;	372	&schedule while 1;
		373	} else {
		374	$self->_cancel;
		375	}
292	}	376	}
293		377
294	=item $coroutine->join	378	=item $coroutine->join
295		379
296	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
…		…
299		383
300	=cut	384	=cut
301		385
302	sub join {	386	sub join {
303	my $self = shift;	387	my $self = shift;
		388
304	unless ($self->{status}) {	389	unless ($self->{status}) {
305	push @{$self->{join}}, $current;	390	my $current = $current;
306	&schedule;	391
		392	push @{$self->{destroy_cb}}, sub {
		393	$current->ready;
		394	undef $current;
		395	};
		396
		397	&schedule while $current;
307	}	398	}
		399
308	wantarray ? @{$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;
309	}	415	}
310		416
311	=item $oldprio = $coroutine->prio ($newprio)	417	=item $oldprio = $coroutine->prio ($newprio)
312		418
313	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
…		…
348	$old;	454	$old;
349	}	455	}
350		456
351	=back	457	=back
352		458
353	=head2 UTILITY FUNCTIONS	459	=head2 GLOBAL FUNCTIONS
354		460
355	=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
356		504
357	=item unblock_sub { ... }	505	=item unblock_sub { ... }
358		506
359	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,
360	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
…		…
374	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
375	creating event callbacks that want to block.	523	creating event callbacks that want to block.
376		524
377	=cut	525	=cut
378		526
379	our @unblock_pool;
380	our @unblock_queue;	527	our @unblock_queue;
381	our $UNBLOCK_POOL_SIZE = 2;
382		528
383	sub unblock_handler_ {	529	# we create a special coro because we want to cede,
384	while () {	530	# to reduce pressure on the coro pool (because most callbacks
385	my ($cb, @arg) = @{ delete $Coro::current->{arg} };	531	# return immediately and can be reused) and because we cannot cede
386	$cb->(@arg);	532	# inside an event callback.
387
388	last if @unblock_pool >= $UNBLOCK_POOL_SIZE;
389	push @unblock_pool, $Coro::current;
390	schedule;
391	}
392	}
393
394	our $unblock_scheduler = async {	533	our $unblock_scheduler = async {
395	while () {	534	while () {
396	while (my $cb = pop @unblock_queue) {	535	while (my $cb = pop @unblock_queue) {
		536	# this is an inlined copy of async_pool
397	my $handler = (pop @unblock_pool or new Coro \&unblock_handler_);	537	my $coro = (pop @pool or new Coro \&pool_handler);
398	$handler->{arg} = $cb;	538
		539	$coro->{_invoke} = $cb;
399	$handler->ready;	540	$coro->ready;
400	cede;	541	cede; # for short-lived callbacks, this reduces pressure on the coro pool
401	}	542	}
402		543	schedule; # sleep well
403	schedule;
404	}	544	}
405	};	545	};
406		546
407	sub unblock_sub(&) {	547	sub unblock_sub(&) {
408	my $cb = shift;	548	my $cb = shift;
409		549
410	sub {	550	sub {
411	push @unblock_queue, [$cb, @_];	551	unshift @unblock_queue, [$cb, @_];
412	$unblock_scheduler->ready;	552	$unblock_scheduler->ready;
413	}	553	}
414	}	554	}
415		555
416	=back	556	=back

Diff Legend

-–
+Removed lines
-+
+Added lines
-<
+Changed lines
->
+Changed lines

Comparing Coro/Coro.pm (file contents): Revision 1.96 by root, Mon Dec 4 03:48:16 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 1.96 by root, Mon Dec 4 03:48:16 2006 UTC vs.
Revision 1.121 by root, Fri Apr 13 12:56:55 2007 UTC