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

Comparing Coro/Coro.pm (file contents):
Revision 1.93 by root, Fri Dec 1 19:41:06 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 $init;
57		66
…		…
99		108
100	The current coroutine (the last coroutine switched to). The initial value	109	The current coroutine (the last coroutine switched to). The initial value
101	is C<$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	$main->{specific} = $current->{specific}	121	$main->{_specific} = $current->{_specific}
111	if $current;	122	if $current;
112		123
113	_set_current $main;	124	_set_current $main;
114		125
115	sub current() { $current }	126	sub current() { $current }
…		…
128	handlers), then it must be prepared to be called recursively.	139	handlers), then it must be prepared to be called recursively.
129		140
130	=cut	141	=cut
131		142
132	$idle = sub {	143	$idle = sub {
133	print STDERR "FATAL: deadlock detected\n";	144	require Carp;
134	exit (51);	145	Carp::croak ("FATAL: deadlock detected");
135	};	146	};
		147
		148	sub _cancel {
		149	my ($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	}
136		159
137	# this coroutine is necessary because a coroutine	160	# this coroutine is necessary because a coroutine
138	# cannot destroy itself.	161	# cannot destroy itself.
139	my @destroy;	162	my @destroy;
		163	my $manager;
		164
140	my $manager; $manager = new Coro sub {	165	$manager = new Coro sub {
141	while () {	166	while () {
142	# by overwriting the state object with the manager we destroy it	167	(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) {	168	while @destroy;
148	my $coro = pop @destroy;
149	$coro->{status} \|\|= [];
150	$_->ready for @{delete $coro->{join} \|\| []};
151		169
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;	170	&schedule;
159	}	171	}
160	};	172	};
		173	$manager->desc ("[coro manager]");
		174	$manager->prio (PRIO_MAX);
161		175
162	# static methods. not really.	176	# static methods. not really.
163		177
164	=back	178	=back
165		179
…		…
173		187
174	Create a new asynchronous coroutine and return it's coroutine object	188	Create a new asynchronous coroutine and return it's coroutine object
175	(usually unused). When the sub returns the new coroutine is automatically	189	(usually unused). When the sub returns the new coroutine is automatically
176	terminated.	190	terminated.
177		191
178	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.
179		194
180	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
181	program.	196	the coroutine. Likewise, when the coroutine dies, the program will exit,
		197	just as it would in the main program.
182		198
183	# create a new coroutine that just prints its arguments	199	# create a new coroutine that just prints its arguments
184	async {	200	async {
185	print "@_\n";	201	print "@_\n";
186	} 1,2,3,4;	202	} 1,2,3,4;
187		203
188	=cut	204	=cut
189		205
190	sub async(&@) {	206	sub async(&@) {
191	my $pid = new Coro @_;	207	my $coro = new Coro @_;
192	$pid->ready;	208	$coro->ready;
193	$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
194	}	273	}
195		274
196	=item schedule	275	=item schedule
197		276
198	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
…		…
211	# wake up sleeping coroutine	290	# wake up sleeping coroutine
212	$current->ready;	291	$current->ready;
213	undef $current;	292	undef $current;
214	};	293	};
215		294
216	# call schedule until event occured.	295	# call schedule until event occurred.
217	# in case we are woken up for other reasons	296	# in case we are woken up for other reasons
218	# (current still defined), loop.	297	# (current still defined), loop.
219	Coro::schedule while $current;	298	Coro::schedule while $current;
220	}	299	}
221		300
…		…
223		302
224	"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
225	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
226	current "timeslice" to other coroutines of the same or higher priority.	305	current "timeslice" to other coroutines of the same or higher priority.
227		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
228	=item terminate [arg...]	316	=item terminate [arg...]
229		317
230	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.
231		325
232	=cut	326	=cut
233		327
234	sub terminate {	328	sub terminate {
235	$current->cancel (@_);	329	$current->cancel (@_);
		330	}
		331
		332	sub killall {
		333	for (Coro::State::list) {
		334	$_->cancel
		335	if $_ != $current && UNIVERSAL::isa $_, "Coro";
		336	}
236	}	337	}
237		338
238	=back	339	=back
239		340
240	# dynamic methods	341	# dynamic methods
…		…
250	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
251	automatically terminates as if C<terminate> with the returned values were	352	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	353	called. To make the coroutine run you must first put it into the ready queue
253	by calling the ready method.	354	by calling the ready method.
254		355
255	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.
256		358
257	=cut	359	=cut
258		360
259	sub _new_coro {	361	sub _run_coro {
260	terminate &{+shift};	362	terminate &{+shift};
261	}	363	}
262		364
263	sub new {	365	sub new {
264	my $class = shift;	366	my $class = shift;
265		367
266	$class->SUPER::new (\&_new_coro, @_)	368	$class->SUPER::new (\&_run_coro, @_)
267	}	369	}
268		370
269	=item $success = $coroutine->ready	371	=item $success = $coroutine->ready
270		372
271	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)
…		…
277	Return wether the coroutine is currently the ready queue or not,	379	Return wether the coroutine is currently the ready queue or not,
278		380
279	=item $coroutine->cancel (arg...)	381	=item $coroutine->cancel (arg...)
280		382
281	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
282	status (default: the empty list).	384	status (default: the empty list). Never returns if the coroutine is the
		385	current coroutine.
283		386
284	=cut	387	=cut
285		388
286	sub cancel {	389	sub cancel {
287	my $self = shift;	390	my $self = shift;
288	$self->{status} = [@_];	391	$self->{_status} = [@_];
		392
		393	if ($current == $self) {
289	push @destroy, $self;	394	push @destroy, $self;
290	$manager->ready;	395	$manager->ready;
291	&schedule if $current == $self;	396	&schedule while 1;
		397	} else {
		398	$self->_cancel;
		399	}
292	}	400	}
293		401
294	=item $coroutine->join	402	=item $coroutine->join
295		403
296	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
297	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
298	from multiple coroutine.	406	from multiple coroutines.
299		407
300	=cut	408	=cut
301		409
302	sub join {	410	sub join {
303	my $self = shift;	411	my $self = shift;
		412
304	unless ($self->{status}) {	413	unless ($self->{_status}) {
305	push @{$self->{join}}, $current;	414	my $current = $current;
306	&schedule;	415
		416	push @{$self->{_on_destroy}}, sub {
		417	$current->ready;
		418	undef $current;
		419	};
		420
		421	&schedule while $current;
307	}	422	}
		423
308	wantarray ? @{$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;
309	}	439	}
310		440
311	=item $oldprio = $coroutine->prio ($newprio)	441	=item $oldprio = $coroutine->prio ($newprio)
312		442
313	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
…		…
338	=item $olddesc = $coroutine->desc ($newdesc)	468	=item $olddesc = $coroutine->desc ($newdesc)
339		469
340	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
341	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.
342		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
343	=cut	476	=cut
344		477
345	sub desc {	478	sub desc {
346	my $old = $_[0]{desc};	479	my $old = $_[0]{desc};
347	$_[0]{desc} = $_[1] if @_ > 1;	480	$_[0]{desc} = $_[1] if @_ > 1;
348	$old;	481	$old;
349	}	482	}
350		483
351	=back	484	=back
352		485
353	=head2 UTILITY FUNCTIONS	486	=head2 GLOBAL FUNCTIONS
354		487
355	=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
356		531
357	=item unblock_sub { ... }	532	=item unblock_sub { ... }
358		533
359	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,
360	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
361	immediately without blocking, returning nothing, while the original code	536	immediately without blocking, returning nothing, while the original code
362	ref will be called (with parameters) from within its own coroutine.	537	ref will be called (with parameters) from within its own coroutine.
363		538
364	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
365	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
366	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,
367	otherwise you might suffer from crashes or worse.	542	otherwise you might suffer from crashes or worse.
368		543
369	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
…		…
374	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
375	creating event callbacks that want to block.	550	creating event callbacks that want to block.
376		551
377	=cut	552	=cut
378		553
379	our @unblock_pool;
380	our @unblock_queue;	554	our @unblock_queue;
381	our $UNBLOCK_POOL_SIZE = 2;
382		555
383	sub unblock_handler_ {	556	# we create a special coro because we want to cede,
384	while () {	557	# to reduce pressure on the coro pool (because most callbacks
385	my ($cb, @arg) = @{ delete $Coro::current->{arg} };	558	# return immediately and can be reused) and because we cannot cede
386	$cb->(@arg);	559	# 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 {	560	our $unblock_scheduler = new Coro sub {
395	while () {	561	while () {
396	while (my $cb = pop @unblock_queue) {	562	while (my $cb = pop @unblock_queue) {
397	my $handler = (pop @unblock_pool or new Coro \&unblock_handler_);	563	# this is an inlined copy of async_pool
398	$handler->{arg} = $cb;	564	my $coro = (pop @async_pool) \|\| new Coro \&pool_handler;
		565
		566	$coro->{_invoke} = $cb;
399	$handler->ready;	567	$coro->ready;
400	cede;	568	cede; # for short-lived callbacks, this reduces pressure on the coro pool
401	}	569	}
402		570	schedule; # sleep well
403	schedule;
404	}	571	}
405	};	572	};
		573	$unblock_scheduler->desc ("[unblock_sub scheduler]");
406		574
407	sub unblock_sub(&) {	575	sub unblock_sub(&) {
408	my $cb = shift;	576	my $cb = shift;
409		577
410	sub {	578	sub {
411	push @unblock_queue, [$cb, @_];	579	unshift @unblock_queue, [$cb, @_];
412	$unblock_scheduler->ready;	580	$unblock_scheduler->ready;
413	}	581	}
414	}	582	}
415		583
416	=back	584	=back
…		…
423		591
424	- 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
425	destruction. very bad things might happen otherwise (usually segfaults).	593	destruction. very bad things might happen otherwise (usually segfaults).
426		594
427	- 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
428	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
429	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
430	this).	598	this).
431		599
432	=head1 SEE ALSO	600	=head1 SEE ALSO
433		601
434	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>.
435		603
436	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>.
437		605
438	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>.
439		607

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Comparing Coro/Coro.pm (file contents): Revision 1.93 by root, Fri Dec 1 19:41:06 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 1.93 by root, Fri Dec 1 19:41:06 2006 UTC vs.
Revision 1.148 by root, Fri Oct 5 20:11:25 2007 UTC