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

Comparing Coro/Coro.pm (file contents):
Revision 1.98 by root, Mon Dec 4 21:56:00 2006 UTC vs.
Revision 1.148 by root, Fri Oct 5 20:11:25 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 = '3.1';	55	our $VERSION = '4.01';
56		56
57	our @EXPORT = qw(async cede schedule terminate current unblock_sub);	57	our @EXPORT = qw(async async_pool cede schedule terminate current unblock_sub);
58	our %EXPORT_TAGS = (	58	our %EXPORT_TAGS = (
59	prio => [qw(PRIO_MAX PRIO_HIGH PRIO_NORMAL PRIO_LOW PRIO_IDLE PRIO_MIN)],	59	prio => [qw(PRIO_MAX PRIO_HIGH PRIO_NORMAL PRIO_LOW PRIO_IDLE PRIO_MIN)],
60	);	60	);
61	our @EXPORT_OK = (@{$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	$coro->{status} \|\|= [];
159	$_->ready for @{delete $coro->{join} \|\| []};
160		169
161	# the next line destroys the coro state, but keeps the
162	# coroutine itself intact (we basically make it a zombie
163	# coroutine that always runs the manager thread, so it's possible
164	# to transfer() to this coroutine).
165	$coro->_clone_state_from ($manager);
166	}
167	&schedule;	170	&schedule;
168	}	171	}
169	};	172	};
		173	$manager->desc ("[coro manager]");
		174	$manager->prio (PRIO_MAX);
170		175
171	# static methods. not really.	176	# static methods. not really.
172		177
173	=back	178	=back
174		179
…		…
182		187
183	Create a new asynchronous coroutine and return it's coroutine object	188	Create a new asynchronous coroutine and return it's coroutine object
184	(usually unused). When the sub returns the new coroutine is automatically	189	(usually unused). When the sub returns the new coroutine is automatically
185	terminated.	190	terminated.
186		191
187	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.
188		194
189	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
190	program.	196	the coroutine. Likewise, when the coroutine dies, the program will exit,
		197	just as it would in the main program.
191		198
192	# create a new coroutine that just prints its arguments	199	# create a new coroutine that just prints its arguments
193	async {	200	async {
194	print "@_\n";	201	print "@_\n";
195	} 1,2,3,4;	202	} 1,2,3,4;
196		203
197	=cut	204	=cut
198		205
199	sub async(&@) {	206	sub async(&@) {
200	my $pid = new Coro @_;	207	my $coro = new Coro @_;
201	$pid->ready;	208	$coro->ready;
202	$pid	209	$coro
		210	}
		211
		212	=item async_pool { ... } [@args...]
		213
		214	Similar to C<async>, but uses a coroutine pool, so you should not call
		215	terminate or join (although you are allowed to), and you get a coroutine
		216	that might have executed other code already (which can be good or bad :).
		217
		218	Also, the block is executed in an C<eval> context and a warning will be
		219	issued in case of an exception instead of terminating the program, as
		220	C<async> does. As the coroutine is being reused, stuff like C<on_destroy>
		221	will not work in the expected way, unless you call terminate or cancel,
		222	which somehow defeats the purpose of pooling.
		223
		224	The priority will be reset to C<0> after each job, tracing will be
		225	disabled, the description will be reset and the default output filehandle
		226	gets restored, so you can change alkl these. Otherwise the coroutine will
		227	be re-used "as-is": most notably if you change other per-coroutine global
		228	stuff such as C<$/> you need to revert that change, which is most simply
		229	done by using local as in C< local $/ >.
		230
		231	The pool size is limited to 8 idle coroutines (this can be adjusted by
		232	changing $Coro::POOL_SIZE), and there can be as many non-idle coros as
		233	required.
		234
		235	If you are concerned about pooled coroutines growing a lot because a
		236	single C<async_pool> used a lot of stackspace you can e.g. C<async_pool
		237	{ terminate }> once per second or so to slowly replenish the pool. In
		238	addition to that, when the stacks used by a handler grows larger than 16kb
		239	(adjustable with $Coro::POOL_RSS) it will also exit.
		240
		241	=cut
		242
		243	our $POOL_SIZE = 8;
		244	our $POOL_RSS = 16 * 1024;
		245	our @async_pool;
		246
		247	sub pool_handler {
		248	my $cb;
		249
		250	while () {
		251	eval {
		252	while () {
		253	_pool_1 $cb;
		254	&$cb;
		255	_pool_2 $cb;
		256	&schedule;
		257	}
		258	};
		259
		260	last if $@ eq "\3terminate\2\n";
		261	warn $@ if $@;
		262	}
		263	}
		264
		265	sub async_pool(&@) {
		266	# this is also inlined into the unlock_scheduler
		267	my $coro = (pop @async_pool) \|\| new Coro \&pool_handler;
		268
		269	$coro->{_invoke} = [@_];
		270	$coro->ready;
		271
		272	$coro
203	}	273	}
204		274
205	=item schedule	275	=item schedule
206		276
207	Calls the scheduler. Please note that the current coroutine will not be put	277	Calls the scheduler. Please note that the current coroutine will not be put
…		…
220	# wake up sleeping coroutine	290	# wake up sleeping coroutine
221	$current->ready;	291	$current->ready;
222	undef $current;	292	undef $current;
223	};	293	};
224		294
225	# call schedule until event occured.	295	# call schedule until event occurred.
226	# in case we are woken up for other reasons	296	# in case we are woken up for other reasons
227	# (current still defined), loop.	297	# (current still defined), loop.
228	Coro::schedule while $current;	298	Coro::schedule while $current;
229	}	299	}
230		300
…		…
232		302
233	"Cede" to other coroutines. This function puts the current coroutine into the	303	"Cede" to other coroutines. This function puts the current coroutine into the
234	ready queue and calls C<schedule>, which has the effect of giving up the	304	ready queue and calls C<schedule>, which has the effect of giving up the
235	current "timeslice" to other coroutines of the same or higher priority.	305	current "timeslice" to other coroutines of the same or higher priority.
236		306
		307	Returns true if at least one coroutine switch has happened.
		308
		309	=item Coro::cede_notself
		310
		311	Works like cede, but is not exported by default and will cede to any
		312	coroutine, regardless of priority, once.
		313
		314	Returns true if at least one coroutine switch has happened.
		315
237	=item terminate [arg...]	316	=item terminate [arg...]
238		317
239	Terminates the current coroutine with the given status values (see L<cancel>).	318	Terminates the current coroutine with the given status values (see L<cancel>).
		319
		320	=item killall
		321
		322	Kills/terminates/cancels all coroutines except the currently running
		323	one. This is useful after a fork, either in the child or the parent, as
		324	usually only one of them should inherit the running coroutines.
240		325
241	=cut	326	=cut
242		327
243	sub terminate {	328	sub terminate {
244	$current->cancel (@_);	329	$current->cancel (@_);
		330	}
		331
		332	sub killall {
		333	for (Coro::State::list) {
		334	$_->cancel
		335	if $_ != $current && UNIVERSAL::isa $_, "Coro";
		336	}
245	}	337	}
246		338
247	=back	339	=back
248		340
249	# dynamic methods	341	# dynamic methods
…		…
259	Create a new coroutine and return it. When the sub returns the coroutine	351	Create a new coroutine and return it. When the sub returns the coroutine
260	automatically terminates as if C<terminate> with the returned values were	352	automatically terminates as if C<terminate> with the returned values were
261	called. To make the coroutine run you must first put it into the ready queue	353	called. To make the coroutine run you must first put it into the ready queue
262	by calling the ready method.	354	by calling the ready method.
263		355
264	Calling C<exit> in a coroutine will not work correctly, so do not do that.	356	See C<async> and C<Coro::State::new> for additional info about the
		357	coroutine environment.
265		358
266	=cut	359	=cut
267		360
268	sub _run_coro {	361	sub _run_coro {
269	terminate &{+shift};	362	terminate &{+shift};
…		…
286	Return wether the coroutine is currently the ready queue or not,	379	Return wether the coroutine is currently the ready queue or not,
287		380
288	=item $coroutine->cancel (arg...)	381	=item $coroutine->cancel (arg...)
289		382
290	Terminates the given coroutine and makes it return the given arguments as	383	Terminates the given coroutine and makes it return the given arguments as
291	status (default: the empty list).	384	status (default: the empty list). Never returns if the coroutine is the
		385	current coroutine.
292		386
293	=cut	387	=cut
294		388
295	sub cancel {	389	sub cancel {
296	my $self = shift;	390	my $self = shift;
297	$self->{status} = [@_];	391	$self->{_status} = [@_];
		392
		393	if ($current == $self) {
298	push @destroy, $self;	394	push @destroy, $self;
299	$manager->ready;	395	$manager->ready;
300	&schedule if $current == $self;	396	&schedule while 1;
		397	} else {
		398	$self->_cancel;
		399	}
301	}	400	}
302		401
303	=item $coroutine->join	402	=item $coroutine->join
304		403
305	Wait until the coroutine terminates and return any values given to the	404	Wait until the coroutine terminates and return any values given to the
306	C<terminate> or C<cancel> functions. C<join> can be called multiple times	405	C<terminate> or C<cancel> functions. C<join> can be called concurrently
307	from multiple coroutine.	406	from multiple coroutines.
308		407
309	=cut	408	=cut
310		409
311	sub join {	410	sub join {
312	my $self = shift;	411	my $self = shift;
		412
313	unless ($self->{status}) {	413	unless ($self->{_status}) {
314	push @{$self->{join}}, $current;	414	my $current = $current;
315	&schedule;	415
		416	push @{$self->{_on_destroy}}, sub {
		417	$current->ready;
		418	undef $current;
		419	};
		420
		421	&schedule while $current;
316	}	422	}
		423
317	wantarray ? @{$self->{status}} : $self->{status}[0];	424	wantarray ? @{$self->{_status}} : $self->{_status}[0];
		425	}
		426
		427	=item $coroutine->on_destroy (\&cb)
		428
		429	Registers a callback that is called when this coroutine gets destroyed,
		430	but before it is joined. The callback gets passed the terminate arguments,
		431	if any.
		432
		433	=cut
		434
		435	sub on_destroy {
		436	my ($self, $cb) = @_;
		437
		438	push @{ $self->{_on_destroy} }, $cb;
318	}	439	}
319		440
320	=item $oldprio = $coroutine->prio ($newprio)	441	=item $oldprio = $coroutine->prio ($newprio)
321		442
322	Sets (or gets, if the argument is missing) the priority of the	443	Sets (or gets, if the argument is missing) the priority of the
…		…
347	=item $olddesc = $coroutine->desc ($newdesc)	468	=item $olddesc = $coroutine->desc ($newdesc)
348		469
349	Sets (or gets in case the argument is missing) the description for this	470	Sets (or gets in case the argument is missing) the description for this
350	coroutine. This is just a free-form string you can associate with a coroutine.	471	coroutine. This is just a free-form string you can associate with a coroutine.
351		472
		473	This method simply sets the C<< $coroutine->{desc} >> member to the given string. You
		474	can modify this member directly if you wish.
		475
352	=cut	476	=cut
353		477
354	sub desc {	478	sub desc {
355	my $old = $_[0]{desc};	479	my $old = $_[0]{desc};
356	$_[0]{desc} = $_[1] if @_ > 1;	480	$_[0]{desc} = $_[1] if @_ > 1;
…		…
364	=over 4	488	=over 4
365		489
366	=item Coro::nready	490	=item Coro::nready
367		491
368	Returns the number of coroutines that are currently in the ready state,	492	Returns the number of coroutines that are currently in the ready state,
369	i.e. that can be swicthed to. The value C<0> means that the only runnable	493	i.e. that can be switched to. The value C<0> means that the only runnable
370	coroutine is the currently running one, so C<cede> would have no effect,	494	coroutine is the currently running one, so C<cede> would have no effect,
371	and C<schedule> would cause a deadlock unless there is an idle handler	495	and C<schedule> would cause a deadlock unless there is an idle handler
372	that wakes up some coroutines.	496	that wakes up some coroutines.
		497
		498	=item my $guard = Coro::guard { ... }
		499
		500	This creates and returns a guard object. Nothing happens until the object
		501	gets destroyed, in which case the codeblock given as argument will be
		502	executed. This is useful to free locks or other resources in case of a
		503	runtime error or when the coroutine gets canceled, as in both cases the
		504	guard block will be executed. The guard object supports only one method,
		505	C<< ->cancel >>, which will keep the codeblock from being executed.
		506
		507	Example: set some flag and clear it again when the coroutine gets canceled
		508	or the function returns:
		509
		510	sub do_something {
		511	my $guard = Coro::guard { $busy = 0 };
		512	$busy = 1;
		513
		514	# do something that requires $busy to be true
		515	}
		516
		517	=cut
		518
		519	sub guard(&) {
		520	bless \(my $cb = $_[0]), "Coro::guard"
		521	}
		522
		523	sub Coro::guard::cancel {
		524	${$_[0]} = sub { };
		525	}
		526
		527	sub Coro::guard::DESTROY {
		528	${$_[0]}->();
		529	}
		530
373		531
374	=item unblock_sub { ... }	532	=item unblock_sub { ... }
375		533
376	This utility function takes a BLOCK or code reference and "unblocks" it,	534	This utility function takes a BLOCK or code reference and "unblocks" it,
377	returning the new coderef. This means that the new coderef will return	535	returning the new coderef. This means that the new coderef will return
378	immediately without blocking, returning nothing, while the original code	536	immediately without blocking, returning nothing, while the original code
379	ref will be called (with parameters) from within its own coroutine.	537	ref will be called (with parameters) from within its own coroutine.
380		538
381	The reason this fucntion exists is that many event libraries (such as the	539	The reason this function exists is that many event libraries (such as the
382	venerable L<Event\|Event> module) are not coroutine-safe (a weaker form	540	venerable L<Event\|Event> module) are not coroutine-safe (a weaker form
383	of thread-safety). This means you must not block within event callbacks,	541	of thread-safety). This means you must not block within event callbacks,
384	otherwise you might suffer from crashes or worse.	542	otherwise you might suffer from crashes or worse.
385		543
386	This function allows your callbacks to block by executing them in another	544	This function allows your callbacks to block by executing them in another
…		…
391	In short: simply use C<unblock_sub { ... }> instead of C<sub { ... }> when	549	In short: simply use C<unblock_sub { ... }> instead of C<sub { ... }> when
392	creating event callbacks that want to block.	550	creating event callbacks that want to block.
393		551
394	=cut	552	=cut
395		553
396	our @unblock_pool;
397	our @unblock_queue;	554	our @unblock_queue;
398	our $UNBLOCK_POOL_SIZE = 2;
399		555
400	sub unblock_handler_ {	556	# we create a special coro because we want to cede,
401	while () {	557	# to reduce pressure on the coro pool (because most callbacks
402	my ($cb, @arg) = @{ delete $Coro::current->{arg} };	558	# return immediately and can be reused) and because we cannot cede
403	$cb->(@arg);	559	# inside an event callback.
404
405	last if @unblock_pool >= $UNBLOCK_POOL_SIZE;
406	push @unblock_pool, $Coro::current;
407	schedule;
408	}
409	}
410
411	our $unblock_scheduler = async {	560	our $unblock_scheduler = new Coro sub {
412	while () {	561	while () {
413	while (my $cb = pop @unblock_queue) {	562	while (my $cb = pop @unblock_queue) {
414	my $handler = (pop @unblock_pool or new Coro \&unblock_handler_);	563	# this is an inlined copy of async_pool
415	$handler->{arg} = $cb;	564	my $coro = (pop @async_pool) \|\| new Coro \&pool_handler;
		565
		566	$coro->{_invoke} = $cb;
416	$handler->ready;	567	$coro->ready;
417	cede;	568	cede; # for short-lived callbacks, this reduces pressure on the coro pool
418	}	569	}
419		570	schedule; # sleep well
420	schedule;
421	}	571	}
422	};	572	};
		573	$unblock_scheduler->desc ("[unblock_sub scheduler]");
423		574
424	sub unblock_sub(&) {	575	sub unblock_sub(&) {
425	my $cb = shift;	576	my $cb = shift;
426		577
427	sub {	578	sub {
428	push @unblock_queue, [$cb, @_];	579	unshift @unblock_queue, [$cb, @_];
429	$unblock_scheduler->ready;	580	$unblock_scheduler->ready;
430	}	581	}
431	}	582	}
432		583
433	=back	584	=back
…		…
440		591
441	- you must make very sure that no coro is still active on global	592	- you must make very sure that no coro is still active on global
442	destruction. very bad things might happen otherwise (usually segfaults).	593	destruction. very bad things might happen otherwise (usually segfaults).
443		594
444	- this module is not thread-safe. You should only ever use this module	595	- this module is not thread-safe. You should only ever use this module
445	from the same thread (this requirement might be losened in the future	596	from the same thread (this requirement might be loosened in the future
446	to allow per-thread schedulers, but Coro::State does not yet allow	597	to allow per-thread schedulers, but Coro::State does not yet allow
447	this).	598	this).
448		599
449	=head1 SEE ALSO	600	=head1 SEE ALSO
450		601
451	Support/Utility: L<Coro::Cont>, L<Coro::Specific>, L<Coro::State>, L<Coro::Util>.	602	Support/Utility: L<Coro::Specific>, L<Coro::State>, L<Coro::Util>.
452		603
453	Locking/IPC: L<Coro::Signal>, L<Coro::Channel>, L<Coro::Semaphore>, L<Coro::SemaphoreSet>, L<Coro::RWLock>.	604	Locking/IPC: L<Coro::Signal>, L<Coro::Channel>, L<Coro::Semaphore>, L<Coro::SemaphoreSet>, L<Coro::RWLock>.
454		605
455	Event/IO: L<Coro::Timer>, L<Coro::Event>, L<Coro::Handle>, L<Coro::Socket>, L<Coro::Select>.	606	Event/IO: L<Coro::Timer>, L<Coro::Event>, L<Coro::Handle>, L<Coro::Socket>, L<Coro::Select>.
456		607

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Comparing Coro/Coro.pm (file contents): Revision 1.98 by root, Mon Dec 4 21:56:00 2006 UTC vs. Revision 1.148 by root, Fri Oct 5 20:11:25 2007 UTC

Diff Legend

Comparing Coro/Coro.pm (file contents):
Revision 1.98 by root, Mon Dec 4 21:56:00 2006 UTC vs.
Revision 1.148 by root, Fri Oct 5 20:11:25 2007 UTC