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

Comparing Coro/Coro.pm (file contents):
Revision 1.102 by root, Fri Dec 29 11:37:49 2006 UTC vs.
Revision 1.139 by root, Thu Sep 27 15:52:30 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 = '3.3';	55	our $VERSION = '3.8';
56		56
57	our @EXPORT = qw(async cede schedule terminate current unblock_sub);	57	our @EXPORT = qw(async async_pool cede schedule terminate current unblock_sub);
58	our %EXPORT_TAGS = (	58	our %EXPORT_TAGS = (
59	prio => [qw(PRIO_MAX PRIO_HIGH PRIO_NORMAL PRIO_LOW PRIO_IDLE PRIO_MIN)],	59	prio => [qw(PRIO_MAX PRIO_HIGH PRIO_NORMAL PRIO_LOW PRIO_IDLE PRIO_MIN)],
60	);	60	);
61	our @EXPORT_OK = (@{$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
		118	$main->{desc} = "[main::]";
117		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
…		…
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 $self->{destroy_cb}) \|\| []};
		158	}
		159
		160	sub _do_trace_sub {
		161	&{$current->{_trace_sub_cb}}
		162	}
		163
		164	sub _do_trace_line {
		165	&{$current->{_trace_line_cb}}
		166	}
		167
146	# this coroutine is necessary because a coroutine	168	# this coroutine is necessary because a coroutine
147	# cannot destroy itself.	169	# cannot destroy itself.
148	my @destroy;	170	my @destroy;
		171	my $manager;
		172
149	my $manager; $manager = new Coro sub {	173	$manager = new Coro sub {
150	while () {	174	while () {
151	# by overwriting the state object with the manager we destroy it	175	(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) {	176	while @destroy;
157	my $coro = pop @destroy;
158		177
159	$coro->{status} \|\|= [];
160
161	$_->ready for @{(delete $coro->{join} ) \|\| []};
162	$_->(@{$coro->{status}}) for @{(delete $coro->{destroy_cb}) \|\| []};
163
164	# the next line destroys the coro state, but keeps the
165	# coroutine itself intact (we basically make it a zombie
166	# coroutine that always runs the manager thread, so it's possible
167	# to transfer() to this coroutine).
168	$coro->_clone_state_from ($manager);
169	}
170	&schedule;	178	&schedule;
171	}	179	}
172	};	180	};
		181	$manager->desc ("[coro manager]");
		182	$manager->prio (PRIO_MAX);
173		183
174	# static methods. not really.	184	# static methods. not really.
175		185
176	=back	186	=back
177		187
…		…
185		195
186	Create a new asynchronous coroutine and return it's coroutine object	196	Create a new asynchronous coroutine and return it's coroutine object
187	(usually unused). When the sub returns the new coroutine is automatically	197	(usually unused). When the sub returns the new coroutine is automatically
188	terminated.	198	terminated.
189		199
190	Calling C<exit> in a coroutine will not work correctly, so do not do that.	200	Calling C<exit> in a coroutine will do the same as calling exit outside
191		201	the coroutine. Likewise, when the coroutine dies, the program will exit,
192	When the coroutine dies, the program will exit, just as in the main	202	just as it would in the main program.
193	program.
194		203
195	# create a new coroutine that just prints its arguments	204	# create a new coroutine that just prints its arguments
196	async {	205	async {
197	print "@_\n";	206	print "@_\n";
198	} 1,2,3,4;	207	} 1,2,3,4;
199		208
200	=cut	209	=cut
201		210
202	sub async(&@) {	211	sub async(&@) {
203	my $pid = new Coro @_;	212	my $coro = new Coro @_;
204	$pid->ready;	213	$coro->ready;
205	$pid	214	$coro
		215	}
		216
		217	=item async_pool { ... } [@args...]
		218
		219	Similar to C<async>, but uses a coroutine pool, so you should not call
		220	terminate or join (although you are allowed to), and you get a coroutine
		221	that might have executed other code already (which can be good or bad :).
		222
		223	Also, the block is executed in an C<eval> context and a warning will be
		224	issued in case of an exception instead of terminating the program, as
		225	C<async> does. As the coroutine is being reused, stuff like C<on_destroy>
		226	will not work in the expected way, unless you call terminate or cancel,
		227	which somehow defeats the purpose of pooling.
		228
		229	The priority will be reset to C<0> after each job, otherwise the coroutine
		230	will be re-used "as-is".
		231
		232	The pool size is limited to 8 idle coroutines (this can be adjusted by
		233	changing $Coro::POOL_SIZE), and there can be as many non-idle coros as
		234	required.
		235
		236	If you are concerned about pooled coroutines growing a lot because a
		237	single C<async_pool> used a lot of stackspace you can e.g. C<async_pool
		238	{ terminate }> once per second or so to slowly replenish the pool. In
		239	addition to that, when the stacks used by a handler grows larger than 16kb
		240	(adjustable with $Coro::POOL_RSS) it will also exit.
		241
		242	=cut
		243
		244	our $POOL_SIZE = 8;
		245	our $POOL_RSS = 16 * 1024;
		246	our @async_pool;
		247
		248	sub pool_handler {
		249	my $cb;
		250
		251	while () {
		252	eval {
		253	while () {
		254	_pool_1 $cb;
		255	&$cb;
		256	_pool_2 $cb;
		257	&schedule;
		258	}
		259	};
		260
		261	last if $@ eq "\3terminate\2\n";
		262	warn $@ if $@;
		263	}
		264	}
		265
		266	sub async_pool(&@) {
		267	# this is also inlined into the unlock_scheduler
		268	my $coro = (pop @async_pool) \|\| new Coro \&pool_handler;
		269
		270	$coro->{_invoke} = [@_];
		271	$coro->ready;
		272
		273	$coro
206	}	274	}
207		275
208	=item schedule	276	=item schedule
209		277
210	Calls the scheduler. Please note that the current coroutine will not be put	278	Calls the scheduler. Please note that the current coroutine will not be put
…		…
223	# wake up sleeping coroutine	291	# wake up sleeping coroutine
224	$current->ready;	292	$current->ready;
225	undef $current;	293	undef $current;
226	};	294	};
227		295
228	# call schedule until event occured.	296	# call schedule until event occurred.
229	# in case we are woken up for other reasons	297	# in case we are woken up for other reasons
230	# (current still defined), loop.	298	# (current still defined), loop.
231	Coro::schedule while $current;	299	Coro::schedule while $current;
232	}	300	}
233		301
…		…
235		303
236	"Cede" to other coroutines. This function puts the current coroutine into the	304	"Cede" to other coroutines. This function puts the current coroutine into the
237	ready queue and calls C<schedule>, which has the effect of giving up the	305	ready queue and calls C<schedule>, which has the effect of giving up the
238	current "timeslice" to other coroutines of the same or higher priority.	306	current "timeslice" to other coroutines of the same or higher priority.
239		307
		308	Returns true if at least one coroutine switch has happened.
		309
240	=item Coro::cede_notself	310	=item Coro::cede_notself
241		311
242	Works like cede, but is not exported by default and will cede to any	312	Works like cede, but is not exported by default and will cede to any
243	coroutine, regardless of priority, once.	313	coroutine, regardless of priority, once.
		314
		315	Returns true if at least one coroutine switch has happened.
244		316
245	=item terminate [arg...]	317	=item terminate [arg...]
246		318
247	Terminates the current coroutine with the given status values (see L<cancel>).	319	Terminates the current coroutine with the given status values (see L<cancel>).
248		320
…		…
267	Create a new coroutine and return it. When the sub returns the coroutine	339	Create a new coroutine and return it. When the sub returns the coroutine
268	automatically terminates as if C<terminate> with the returned values were	340	automatically terminates as if C<terminate> with the returned values were
269	called. To make the coroutine run you must first put it into the ready queue	341	called. To make the coroutine run you must first put it into the ready queue
270	by calling the ready method.	342	by calling the ready method.
271		343
272	Calling C<exit> in a coroutine will not work correctly, so do not do that.	344	See C<async> for additional discussion.
273		345
274	=cut	346	=cut
275		347
276	sub _run_coro {	348	sub _run_coro {
277	terminate &{+shift};	349	terminate &{+shift};
…		…
294	Return wether the coroutine is currently the ready queue or not,	366	Return wether the coroutine is currently the ready queue or not,
295		367
296	=item $coroutine->cancel (arg...)	368	=item $coroutine->cancel (arg...)
297		369
298	Terminates the given coroutine and makes it return the given arguments as	370	Terminates the given coroutine and makes it return the given arguments as
299	status (default: the empty list).	371	status (default: the empty list). Never returns if the coroutine is the
		372	current coroutine.
300		373
301	=cut	374	=cut
302		375
303	sub cancel {	376	sub cancel {
304	my $self = shift;	377	my $self = shift;
305	$self->{status} = [@_];	378	$self->{status} = [@_];
		379
		380	if ($current == $self) {
306	push @destroy, $self;	381	push @destroy, $self;
307	$manager->ready;	382	$manager->ready;
308	&schedule if $current == $self;	383	&schedule while 1;
		384	} else {
		385	$self->_cancel;
		386	}
309	}	387	}
310		388
311	=item $coroutine->join	389	=item $coroutine->join
312		390
313	Wait until the coroutine terminates and return any values given to the	391	Wait until the coroutine terminates and return any values given to the
…		…
316		394
317	=cut	395	=cut
318		396
319	sub join {	397	sub join {
320	my $self = shift;	398	my $self = shift;
		399
321	unless ($self->{status}) {	400	unless ($self->{status}) {
322	push @{$self->{join}}, $current;	401	my $current = $current;
323	&schedule;	402
		403	push @{$self->{destroy_cb}}, sub {
		404	$current->ready;
		405	undef $current;
		406	};
		407
		408	&schedule while $current;
324	}	409	}
		410
325	wantarray ? @{$self->{status}} : $self->{status}[0];	411	wantarray ? @{$self->{status}} : $self->{status}[0];
326	}	412	}
327		413
328	=item $coroutine->on_destroy (\&cb)	414	=item $coroutine->on_destroy (\&cb)
329		415
…		…
386	=over 4	472	=over 4
387		473
388	=item Coro::nready	474	=item Coro::nready
389		475
390	Returns the number of coroutines that are currently in the ready state,	476	Returns the number of coroutines that are currently in the ready state,
391	i.e. that can be swicthed to. The value C<0> means that the only runnable	477	i.e. that can be switched to. The value C<0> means that the only runnable
392	coroutine is the currently running one, so C<cede> would have no effect,	478	coroutine is the currently running one, so C<cede> would have no effect,
393	and C<schedule> would cause a deadlock unless there is an idle handler	479	and C<schedule> would cause a deadlock unless there is an idle handler
394	that wakes up some coroutines.	480	that wakes up some coroutines.
		481
		482	=item my $guard = Coro::guard { ... }
		483
		484	This creates and returns a guard object. Nothing happens until the object
		485	gets destroyed, in which case the codeblock given as argument will be
		486	executed. This is useful to free locks or other resources in case of a
		487	runtime error or when the coroutine gets canceled, as in both cases the
		488	guard block will be executed. The guard object supports only one method,
		489	C<< ->cancel >>, which will keep the codeblock from being executed.
		490
		491	Example: set some flag and clear it again when the coroutine gets canceled
		492	or the function returns:
		493
		494	sub do_something {
		495	my $guard = Coro::guard { $busy = 0 };
		496	$busy = 1;
		497
		498	# do something that requires $busy to be true
		499	}
		500
		501	=cut
		502
		503	sub guard(&) {
		504	bless \(my $cb = $_[0]), "Coro::guard"
		505	}
		506
		507	sub Coro::guard::cancel {
		508	${$_[0]} = sub { };
		509	}
		510
		511	sub Coro::guard::DESTROY {
		512	${$_[0]}->();
		513	}
		514
395		515
396	=item unblock_sub { ... }	516	=item unblock_sub { ... }
397		517
398	This utility function takes a BLOCK or code reference and "unblocks" it,	518	This utility function takes a BLOCK or code reference and "unblocks" it,
399	returning the new coderef. This means that the new coderef will return	519	returning the new coderef. This means that the new coderef will return
400	immediately without blocking, returning nothing, while the original code	520	immediately without blocking, returning nothing, while the original code
401	ref will be called (with parameters) from within its own coroutine.	521	ref will be called (with parameters) from within its own coroutine.
402		522
403	The reason this fucntion exists is that many event libraries (such as the	523	The reason this function exists is that many event libraries (such as the
404	venerable L<Event\|Event> module) are not coroutine-safe (a weaker form	524	venerable L<Event\|Event> module) are not coroutine-safe (a weaker form
405	of thread-safety). This means you must not block within event callbacks,	525	of thread-safety). This means you must not block within event callbacks,
406	otherwise you might suffer from crashes or worse.	526	otherwise you might suffer from crashes or worse.
407		527
408	This function allows your callbacks to block by executing them in another	528	This function allows your callbacks to block by executing them in another
…		…
413	In short: simply use C<unblock_sub { ... }> instead of C<sub { ... }> when	533	In short: simply use C<unblock_sub { ... }> instead of C<sub { ... }> when
414	creating event callbacks that want to block.	534	creating event callbacks that want to block.
415		535
416	=cut	536	=cut
417		537
418	our @unblock_pool;
419	our @unblock_queue;	538	our @unblock_queue;
420	our $UNBLOCK_POOL_SIZE = 2;
421		539
422	sub unblock_handler_ {	540	# we create a special coro because we want to cede,
423	while () {	541	# to reduce pressure on the coro pool (because most callbacks
424	my ($cb, @arg) = @{ delete $Coro::current->{arg} };	542	# return immediately and can be reused) and because we cannot cede
425	$cb->(@arg);	543	# inside an event callback.
426
427	last if @unblock_pool >= $UNBLOCK_POOL_SIZE;
428	push @unblock_pool, $Coro::current;
429	schedule;
430	}
431	}
432
433	our $unblock_scheduler = async {	544	our $unblock_scheduler = new Coro sub {
434	while () {	545	while () {
435	while (my $cb = pop @unblock_queue) {	546	while (my $cb = pop @unblock_queue) {
436	my $handler = (pop @unblock_pool or new Coro \&unblock_handler_);	547	# this is an inlined copy of async_pool
437	$handler->{arg} = $cb;	548	my $coro = (pop @async_pool) \|\| new Coro \&pool_handler;
		549
		550	$coro->{_invoke} = $cb;
438	$handler->ready;	551	$coro->ready;
439	cede;	552	cede; # for short-lived callbacks, this reduces pressure on the coro pool
440	}	553	}
441		554	schedule; # sleep well
442	schedule;
443	}	555	}
444	};	556	};
		557	$unblock_scheduler->desc ("[unblock_sub scheduler]");
445		558
446	sub unblock_sub(&) {	559	sub unblock_sub(&) {
447	my $cb = shift;	560	my $cb = shift;
448		561
449	sub {	562	sub {
450	push @unblock_queue, [$cb, @_];	563	unshift @unblock_queue, [$cb, @_];
451	$unblock_scheduler->ready;	564	$unblock_scheduler->ready;
452	}	565	}
453	}	566	}
454		567
455	=back	568	=back
…		…
462		575
463	- you must make very sure that no coro is still active on global	576	- you must make very sure that no coro is still active on global
464	destruction. very bad things might happen otherwise (usually segfaults).	577	destruction. very bad things might happen otherwise (usually segfaults).
465		578
466	- this module is not thread-safe. You should only ever use this module	579	- this module is not thread-safe. You should only ever use this module
467	from the same thread (this requirement might be losened in the future	580	from the same thread (this requirement might be loosened in the future
468	to allow per-thread schedulers, but Coro::State does not yet allow	581	to allow per-thread schedulers, but Coro::State does not yet allow
469	this).	582	this).
470		583
471	=head1 SEE ALSO	584	=head1 SEE ALSO
472		585

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Comparing Coro/Coro.pm (file contents): Revision 1.102 by root, Fri Dec 29 11:37:49 2006 UTC vs. Revision 1.139 by root, Thu Sep 27 15:52:30 2007 UTC

Diff Legend

Comparing Coro/Coro.pm (file contents):
Revision 1.102 by root, Fri Dec 29 11:37:49 2006 UTC vs.
Revision 1.139 by root, Thu Sep 27 15:52:30 2007 UTC