[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 1.129 by root, Wed Sep 19 22:33:08 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 $VERSION = '3.7';
56		56
57	our @EXPORT = qw(async cede schedule terminate current unblock_sub);	57	our @EXPORT = qw(async async_pool cede schedule terminate current unblock_sub);
58	our %EXPORT_TAGS = (	58	our %EXPORT_TAGS = (
59	prio => [qw(PRIO_MAX PRIO_HIGH PRIO_NORMAL PRIO_LOW PRIO_IDLE PRIO_MIN)],	59	prio => [qw(PRIO_MAX PRIO_HIGH PRIO_NORMAL PRIO_LOW PRIO_IDLE PRIO_MIN)],
60	);	60	);
61	our @EXPORT_OK = (@{$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	# maybe some other module used Coro::Specific before...	118	# maybe some other module used Coro::Specific before...
…		…
141	$idle = sub {	141	$idle = sub {
142	require Carp;	142	require Carp;
143	Carp::croak ("FATAL: deadlock detected");	143	Carp::croak ("FATAL: deadlock detected");
144	};	144	};
145		145
		146	sub _cancel {
		147	my ($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
146	# this coroutine is necessary because a coroutine	158	# this coroutine is necessary because a coroutine
147	# cannot destroy itself.	159	# cannot destroy itself.
148	my @destroy;	160	my @destroy;
		161	my $manager;
		162
149	my $manager; $manager = new Coro sub {	163	$manager = new Coro sub {
		164	$current->desc ("[coro manager]");
		165
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
		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	Calling C<exit> in a coroutine will do the same as calling exit outside
188		193	the coroutine. Likewise, when the coroutine dies, the program will exit,
189	When the coroutine dies, the program will exit, just as in the main	194	just as it would in the main program.
190	program.
191		195
192	# create a new coroutine that just prints its arguments	196	# create a new coroutine that just prints its arguments
193	async {	197	async {
194	print "@_\n";	198	print "@_\n";
195	} 1,2,3,4;	199	} 1,2,3,4;
196		200
197	=cut	201	=cut
198		202
199	sub async(&@) {	203	sub async(&@) {
200	my $pid = new Coro @_;	204	my $coro = new Coro @_;
201	$pid->ready;	205	$coro->ready;
202	$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 @pool;
		236
		237	sub pool_handler {
		238	while () {
		239	$current->{desc} = "[async_pool]";
		240
		241	eval {
		242	my ($cb, @arg) = @{ delete $current->{_invoke} or return };
		243	$cb->(@arg);
		244	};
		245	warn $@ if $@;
		246
		247	last if @pool >= $POOL_SIZE;
		248
		249	push @pool, $current;
		250	$current->{desc} = "[async_pool idle]";
		251	$current->save (Coro::State::SAVE_DEF);
		252	$current->prio (0);
		253	schedule;
		254	}
		255	}
		256
		257	sub async_pool(&@) {
		258	# this is also inlined into the unlock_scheduler
		259	my $coro = (pop @pool) \|\| new Coro \&pool_handler;;
		260
		261	$coro->{_invoke} = [@_];
		262	$coro->ready;
		263
		264	$coro
203	}	265	}
204		266
205	=item schedule	267	=item schedule
206		268
207	Calls the scheduler. Please note that the current coroutine will not be put	269	Calls the scheduler. Please note that the current coroutine will not be put
…		…
220	# wake up sleeping coroutine	282	# wake up sleeping coroutine
221	$current->ready;	283	$current->ready;
222	undef $current;	284	undef $current;
223	};	285	};
224		286
225	# call schedule until event occured.	287	# call schedule until event occurred.
226	# in case we are woken up for other reasons	288	# in case we are woken up for other reasons
227	# (current still defined), loop.	289	# (current still defined), loop.
228	Coro::schedule while $current;	290	Coro::schedule while $current;
229	}	291	}
230		292
231	=item cede	293	=item cede
232		294
233	"Cede" to other coroutines. This function puts the current coroutine into the	295	"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	296	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.	297	current "timeslice" to other coroutines of the same or higher priority.
		298
		299	Returns true if at least one coroutine switch has happened.
		300
		301	=item Coro::cede_notself
		302
		303	Works like cede, but is not exported by default and will cede to any
		304	coroutine, regardless of priority, once.
		305
		306	Returns true if at least one coroutine switch has happened.
236		307
237	=item terminate [arg...]	308	=item terminate [arg...]
238		309
239	Terminates the current coroutine with the given status values (see L<cancel>).	310	Terminates the current coroutine with the given status values (see L<cancel>).
240		311
…		…
259	Create a new coroutine and return it. When the sub returns the coroutine	330	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	331	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	332	called. To make the coroutine run you must first put it into the ready queue
262	by calling the ready method.	333	by calling the ready method.
263		334
264	Calling C<exit> in a coroutine will not work correctly, so do not do that.	335	See C<async> for additional discussion.
265		336
266	=cut	337	=cut
267		338
268	sub _run_coro {	339	sub _run_coro {
269	terminate &{+shift};	340	terminate &{+shift};
…		…
286	Return wether the coroutine is currently the ready queue or not,	357	Return wether the coroutine is currently the ready queue or not,
287		358
288	=item $coroutine->cancel (arg...)	359	=item $coroutine->cancel (arg...)
289		360
290	Terminates the given coroutine and makes it return the given arguments as	361	Terminates the given coroutine and makes it return the given arguments as
291	status (default: the empty list).	362	status (default: the empty list). Never returns if the coroutine is the
		363	current coroutine.
292		364
293	=cut	365	=cut
294		366
295	sub cancel {	367	sub cancel {
296	my $self = shift;	368	my $self = shift;
297	$self->{status} = [@_];	369	$self->{status} = [@_];
		370
		371	if ($current == $self) {
298	push @destroy, $self;	372	push @destroy, $self;
299	$manager->ready;	373	$manager->ready;
300	&schedule if $current == $self;	374	&schedule while 1;
		375	} else {
		376	$self->_cancel;
		377	}
301	}	378	}
302		379
303	=item $coroutine->join	380	=item $coroutine->join
304		381
305	Wait until the coroutine terminates and return any values given to the	382	Wait until the coroutine terminates and return any values given to the
…		…
308		385
309	=cut	386	=cut
310		387
311	sub join {	388	sub join {
312	my $self = shift;	389	my $self = shift;
		390
313	unless ($self->{status}) {	391	unless ($self->{status}) {
314	push @{$self->{join}}, $current;	392	my $current = $current;
315	&schedule;	393
		394	push @{$self->{destroy_cb}}, sub {
		395	$current->ready;
		396	undef $current;
		397	};
		398
		399	&schedule while $current;
316	}	400	}
		401
317	wantarray ? @{$self->{status}} : $self->{status}[0];	402	wantarray ? @{$self->{status}} : $self->{status}[0];
		403	}
		404
		405	=item $coroutine->on_destroy (\&cb)
		406
		407	Registers a callback that is called when this coroutine gets destroyed,
		408	but before it is joined. The callback gets passed the terminate arguments,
		409	if any.
		410
		411	=cut
		412
		413	sub on_destroy {
		414	my ($self, $cb) = @_;
		415
		416	push @{ $self->{destroy_cb} }, $cb;
318	}	417	}
319		418
320	=item $oldprio = $coroutine->prio ($newprio)	419	=item $oldprio = $coroutine->prio ($newprio)
321		420
322	Sets (or gets, if the argument is missing) the priority of the	421	Sets (or gets, if the argument is missing) the priority of the
…		…
364	=over 4	463	=over 4
365		464
366	=item Coro::nready	465	=item Coro::nready
367		466
368	Returns the number of coroutines that are currently in the ready state,	467	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	468	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,	469	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	470	and C<schedule> would cause a deadlock unless there is an idle handler
372	that wakes up some coroutines.	471	that wakes up some coroutines.
		472
		473	=item my $guard = Coro::guard { ... }
		474
		475	This creates and returns a guard object. Nothing happens until the object
		476	gets destroyed, in which case the codeblock given as argument will be
		477	executed. This is useful to free locks or other resources in case of a
		478	runtime error or when the coroutine gets canceled, as in both cases the
		479	guard block will be executed. The guard object supports only one method,
		480	C<< ->cancel >>, which will keep the codeblock from being executed.
		481
		482	Example: set some flag and clear it again when the coroutine gets canceled
		483	or the function returns:
		484
		485	sub do_something {
		486	my $guard = Coro::guard { $busy = 0 };
		487	$busy = 1;
		488
		489	# do something that requires $busy to be true
		490	}
		491
		492	=cut
		493
		494	sub guard(&) {
		495	bless \(my $cb = $_[0]), "Coro::guard"
		496	}
		497
		498	sub Coro::guard::cancel {
		499	${$_[0]} = sub { };
		500	}
		501
		502	sub Coro::guard::DESTROY {
		503	${$_[0]}->();
		504	}
		505
373		506
374	=item unblock_sub { ... }	507	=item unblock_sub { ... }
375		508
376	This utility function takes a BLOCK or code reference and "unblocks" it,	509	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	510	returning the new coderef. This means that the new coderef will return
378	immediately without blocking, returning nothing, while the original code	511	immediately without blocking, returning nothing, while the original code
379	ref will be called (with parameters) from within its own coroutine.	512	ref will be called (with parameters) from within its own coroutine.
380		513
381	The reason this fucntion exists is that many event libraries (such as the	514	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	515	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,	516	of thread-safety). This means you must not block within event callbacks,
384	otherwise you might suffer from crashes or worse.	517	otherwise you might suffer from crashes or worse.
385		518
386	This function allows your callbacks to block by executing them in another	519	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	524	In short: simply use C<unblock_sub { ... }> instead of C<sub { ... }> when
392	creating event callbacks that want to block.	525	creating event callbacks that want to block.
393		526
394	=cut	527	=cut
395		528
396	our @unblock_pool;
397	our @unblock_queue;	529	our @unblock_queue;
398	our $UNBLOCK_POOL_SIZE = 2;
399		530
400	sub unblock_handler_ {	531	# we create a special coro because we want to cede,
401	while () {	532	# to reduce pressure on the coro pool (because most callbacks
402	my ($cb, @arg) = @{ delete $Coro::current->{arg} };	533	# return immediately and can be reused) and because we cannot cede
403	$cb->(@arg);	534	# 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 {	535	our $unblock_scheduler = async {
		536	$current->desc ("[unblock_sub scheduler]");
412	while () {	537	while () {
413	while (my $cb = pop @unblock_queue) {	538	while (my $cb = pop @unblock_queue) {
		539	# this is an inlined copy of async_pool
414	my $handler = (pop @unblock_pool or new Coro \&unblock_handler_);	540	my $coro = (pop @pool or new Coro \&pool_handler);
415	$handler->{arg} = $cb;	541
		542	$coro->{_invoke} = $cb;
416	$handler->ready;	543	$coro->ready;
417	cede;	544	cede; # for short-lived callbacks, this reduces pressure on the coro pool
418	}	545	}
419		546	schedule; # sleep well
420	schedule;
421	}	547	}
422	};	548	};
423		549
424	sub unblock_sub(&) {	550	sub unblock_sub(&) {
425	my $cb = shift;	551	my $cb = shift;
426		552
427	sub {	553	sub {
428	push @unblock_queue, [$cb, @_];	554	unshift @unblock_queue, [$cb, @_];
429	$unblock_scheduler->ready;	555	$unblock_scheduler->ready;
430	}	556	}
431	}	557	}
432		558
433	=back	559	=back
…		…
440		566
441	- you must make very sure that no coro is still active on global	567	- you must make very sure that no coro is still active on global
442	destruction. very bad things might happen otherwise (usually segfaults).	568	destruction. very bad things might happen otherwise (usually segfaults).
443		569
444	- this module is not thread-safe. You should only ever use this module	570	- 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	571	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	572	to allow per-thread schedulers, but Coro::State does not yet allow
447	this).	573	this).
448		574
449	=head1 SEE ALSO	575	=head1 SEE ALSO
450		576

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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 1.129 by root, Wed Sep 19 22:33:08 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 1.129 by root, Wed Sep 19 22:33:08 2007 UTC