[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 1.148 by root, Fri Oct 5 20:11:25 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 used in this module also
		26	guarantees 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 $VERSION = '4.01';
47		56
48	our @EXPORT = qw(async cede schedule terminate current unblock_sub);	57	our @EXPORT = qw(async async_pool cede schedule terminate current unblock_sub);
49	our %EXPORT_TAGS = (	58	our %EXPORT_TAGS = (
50	prio => [qw(PRIO_MAX PRIO_HIGH PRIO_NORMAL PRIO_LOW PRIO_IDLE PRIO_MIN)],	59	prio => [qw(PRIO_MAX PRIO_HIGH PRIO_NORMAL PRIO_LOW PRIO_IDLE PRIO_MIN)],
51	);	60	);
52	our @EXPORT_OK = @{$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, $ref) = (shift, shift);
67	my @attrs;	76	my @attrs;
…		…
99		108
100	The current coroutine (the last coroutine switched to). The initial value	109	The current coroutine (the last coroutine switched to). The initial value
101	is C<$main> (of course).	110	is C<$main> (of course).
102		111
103	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
104	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
105	C<Coro::current> function instead.	114	C<Coro::current> function instead.
106		115
107	=cut	116	=cut
108		117
		118	$main->{desc} = "[main::]";
		119
109	# maybe some other module used Coro::Specific before...	120	# maybe some other module used Coro::Specific before...
110	if ($current) {
111	$main->{specific} = $current->{specific};	121	$main->{_specific} = $current->{_specific}
112	}	122	if $current;
113		123
114	$current = $main;	124	_set_current $main;
115		125
116	sub current() { $current }	126	sub current() { $current }
117		127
118	=item $idle	128	=item $idle
119		129
…		…
129	handlers), then it must be prepared to be called recursively.	139	handlers), then it must be prepared to be called recursively.
130		140
131	=cut	141	=cut
132		142
133	$idle = sub {	143	$idle = sub {
134	print STDERR "FATAL: deadlock detected\n";	144	require Carp;
135	exit (51);	145	Carp::croak ("FATAL: deadlock detected");
136	};	146	};
		147
		148	sub _cancel {
		149	my ($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	}
137		159
138	# this coroutine is necessary because a coroutine	160	# this coroutine is necessary because a coroutine
139	# cannot destroy itself.	161	# cannot destroy itself.
140	my @destroy;	162	my @destroy;
		163	my $manager;
		164
141	my $manager; $manager = new Coro sub {	165	$manager = new Coro sub {
142	while () {	166	while () {
143	# by overwriting the state object with the manager we destroy it	167	(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) {	168	while @destroy;
149	my $coro = pop @destroy;
150	$coro->{status} \|\|= [];
151	$_->ready for @{delete $coro->{join} \|\| []};
152		169
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;	170	&schedule;
160	}	171	}
161	};	172	};
		173	$manager->desc ("[coro manager]");
		174	$manager->prio (PRIO_MAX);
162		175
163	# static methods. not really.	176	# static methods. not really.
164		177
165	=back	178	=back
166		179
…		…
174		187
175	Create a new asynchronous coroutine and return it's coroutine object	188	Create a new asynchronous coroutine and return it's coroutine object
176	(usually unused). When the sub returns the new coroutine is automatically	189	(usually unused). When the sub returns the new coroutine is automatically
177	terminated.	190	terminated.
178		191
179	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.
180		194
181	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
182	program.	196	the coroutine. Likewise, when the coroutine dies, the program will exit,
		197	just as it would in the main program.
183		198
184	# create a new coroutine that just prints its arguments	199	# create a new coroutine that just prints its arguments
185	async {	200	async {
186	print "@_\n";	201	print "@_\n";
187	} 1,2,3,4;	202	} 1,2,3,4;
188		203
189	=cut	204	=cut
190		205
191	sub async(&@) {	206	sub async(&@) {
192	my $pid = new Coro @_;	207	my $coro = new Coro @_;
193	$pid->ready;	208	$coro->ready;
194	$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
195	}	273	}
196		274
197	=item schedule	275	=item schedule
198		276
199	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
…		…
212	# wake up sleeping coroutine	290	# wake up sleeping coroutine
213	$current->ready;	291	$current->ready;
214	undef $current;	292	undef $current;
215	};	293	};
216		294
217	# call schedule until event occured.	295	# call schedule until event occurred.
218	# in case we are woken up for other reasons	296	# in case we are woken up for other reasons
219	# (current still defined), loop.	297	# (current still defined), loop.
220	Coro::schedule while $current;	298	Coro::schedule while $current;
221	}	299	}
222		300
…		…
224		302
225	"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
226	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
227	current "timeslice" to other coroutines of the same or higher priority.	305	current "timeslice" to other coroutines of the same or higher priority.
228		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
229	=item terminate [arg...]	316	=item terminate [arg...]
230		317
231	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.
232		325
233	=cut	326	=cut
234		327
235	sub terminate {	328	sub terminate {
236	$current->cancel (@_);	329	$current->cancel (@_);
		330	}
		331
		332	sub killall {
		333	for (Coro::State::list) {
		334	$_->cancel
		335	if $_ != $current && UNIVERSAL::isa $_, "Coro";
		336	}
237	}	337	}
238		338
239	=back	339	=back
240		340
241	# dynamic methods	341	# dynamic methods
…		…
251	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
252	automatically terminates as if C<terminate> with the returned values were	352	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	353	called. To make the coroutine run you must first put it into the ready queue
254	by calling the ready method.	354	by calling the ready method.
255		355
256	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.
257		358
258	=cut	359	=cut
259		360
260	sub _new_coro {	361	sub _run_coro {
261	terminate &{+shift};	362	terminate &{+shift};
262	}	363	}
263		364
264	sub new {	365	sub new {
265	my $class = shift;	366	my $class = shift;
266		367
267	$class->SUPER::new (\&_new_coro, @_)	368	$class->SUPER::new (\&_run_coro, @_)
268	}	369	}
269		370
270	=item $success = $coroutine->ready	371	=item $success = $coroutine->ready
271		372
272	Put the given coroutine into the ready queue (according to it's priority)	373	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,	379	Return wether the coroutine is currently the ready queue or not,
279		380
280	=item $coroutine->cancel (arg...)	381	=item $coroutine->cancel (arg...)
281		382
282	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
283	status (default: the empty list).	384	status (default: the empty list). Never returns if the coroutine is the
		385	current coroutine.
284		386
285	=cut	387	=cut
286		388
287	sub cancel {	389	sub cancel {
288	my $self = shift;	390	my $self = shift;
289	$self->{status} = [@_];	391	$self->{_status} = [@_];
		392
		393	if ($current == $self) {
290	push @destroy, $self;	394	push @destroy, $self;
291	$manager->ready;	395	$manager->ready;
292	&schedule if $current == $self;	396	&schedule while 1;
		397	} else {
		398	$self->_cancel;
		399	}
293	}	400	}
294		401
295	=item $coroutine->join	402	=item $coroutine->join
296		403
297	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
298	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
299	from multiple coroutine.	406	from multiple coroutines.
300		407
301	=cut	408	=cut
302		409
303	sub join {	410	sub join {
304	my $self = shift;	411	my $self = shift;
		412
305	unless ($self->{status}) {	413	unless ($self->{_status}) {
306	push @{$self->{join}}, $current;	414	my $current = $current;
307	&schedule;	415
		416	push @{$self->{_on_destroy}}, sub {
		417	$current->ready;
		418	undef $current;
		419	};
		420
		421	&schedule while $current;
308	}	422	}
		423
309	wantarray ? @{$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;
310	}	439	}
311		440
312	=item $oldprio = $coroutine->prio ($newprio)	441	=item $oldprio = $coroutine->prio ($newprio)
313		442
314	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
…		…
339	=item $olddesc = $coroutine->desc ($newdesc)	468	=item $olddesc = $coroutine->desc ($newdesc)
340		469
341	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
342	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.
343		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
344	=cut	476	=cut
345		477
346	sub desc {	478	sub desc {
347	my $old = $_[0]{desc};	479	my $old = $_[0]{desc};
348	$_[0]{desc} = $_[1] if @_ > 1;	480	$_[0]{desc} = $_[1] if @_ > 1;
349	$old;	481	$old;
350	}	482	}
351		483
352	=back	484	=back
353		485
354	=head2 UTILITY FUNCTIONS	486	=head2 GLOBAL FUNCTIONS
355		487
356	=over 4	488	=over 4
		489
		490	=item Coro::nready
		491
		492	Returns the number of coroutines that are currently in the ready state,
		493	i.e. that can be switched to. The value C<0> means that the only runnable
		494	coroutine is the currently running one, so C<cede> would have no effect,
		495	and C<schedule> would cause a deadlock unless there is an idle handler
		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
357		531
358	=item unblock_sub { ... }	532	=item unblock_sub { ... }
359		533
360	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,
361	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
362	immediately without blocking, returning nothing, while the original code	536	immediately without blocking, returning nothing, while the original code
363	ref will be called (with parameters) from within its own coroutine.	537	ref will be called (with parameters) from within its own coroutine.
364		538
365	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
366	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
367	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,
368	otherwise you might suffer from crashes or worse.	542	otherwise you might suffer from crashes or worse.
369		543
370	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
…		…
375	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
376	creating event callbacks that want to block.	550	creating event callbacks that want to block.
377		551
378	=cut	552	=cut
379		553
380	our @unblock_pool;
381	our @unblock_queue;	554	our @unblock_queue;
382	our $UNBLOCK_POOL_SIZE = 2;
383		555
384	sub unblock_handler_ {	556	# we create a special coro because we want to cede,
385	while () {	557	# to reduce pressure on the coro pool (because most callbacks
386	my ($cb, @arg) = @{ delete $Coro::current->{arg} };	558	# return immediately and can be reused) and because we cannot cede
387	$cb->(@arg);	559	# 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 {	560	our $unblock_scheduler = new Coro sub {
396	while () {	561	while () {
397	while (my $cb = pop @unblock_queue) {	562	while (my $cb = pop @unblock_queue) {
398	my $handler = (pop @unblock_pool or new Coro \&unblock_handler_);	563	# this is an inlined copy of async_pool
399	$handler->{arg} = $cb;	564	my $coro = (pop @async_pool) \|\| new Coro \&pool_handler;
		565
		566	$coro->{_invoke} = $cb;
400	$handler->ready;	567	$coro->ready;
401	cede;	568	cede; # for short-lived callbacks, this reduces pressure on the coro pool
402	}	569	}
403		570	schedule; # sleep well
404	schedule;
405	}	571	}
406	};	572	};
		573	$unblock_scheduler->desc ("[unblock_sub scheduler]");
407		574
408	sub unblock_sub(&) {	575	sub unblock_sub(&) {
409	my $cb = shift;	576	my $cb = shift;
410		577
411	sub {	578	sub {
412	push @unblock_queue, [$cb, @_];	579	unshift @unblock_queue, [$cb, @_];
413	$unblock_scheduler->ready;	580	$unblock_scheduler->ready;
414	}	581	}
415	}	582	}
416		583
417	=back	584	=back
…		…
424		591
425	- 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
426	destruction. very bad things might happen otherwise (usually segfaults).	593	destruction. very bad things might happen otherwise (usually segfaults).
427		594
428	- 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
429	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
430	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
431	this).	598	this).
432		599
433	=head1 SEE ALSO	600	=head1 SEE ALSO
434		601
435	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>.
436		603
437	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>.
438		605
439	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>.
440		607

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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 1.148 by root, Fri Oct 5 20:11:25 2007 UTC

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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 1.148 by root, Fri Oct 5 20:11:25 2007 UTC