[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 1.139 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 = '3.1';	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	$coro->{status} \|\|= [];
159	$_->ready for @{delete $coro->{join} \|\| []};
160		177
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;	178	&schedule;
168	}	179	}
169	};	180	};
		181	$manager->desc ("[coro manager]");
		182	$manager->prio (PRIO_MAX);
170		183
171	# static methods. not really.	184	# static methods. not really.
172		185
173	=back	186	=back
174		187
…		…
182		195
183	Create a new asynchronous coroutine and return it's coroutine object	196	Create a new asynchronous coroutine and return it's coroutine object
184	(usually unused). When the sub returns the new coroutine is automatically	197	(usually unused). When the sub returns the new coroutine is automatically
185	terminated.	198	terminated.
186		199
187	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
188		201	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	202	just as it would in the main program.
190	program.
191		203
192	# create a new coroutine that just prints its arguments	204	# create a new coroutine that just prints its arguments
193	async {	205	async {
194	print "@_\n";	206	print "@_\n";
195	} 1,2,3,4;	207	} 1,2,3,4;
196		208
197	=cut	209	=cut
198		210
199	sub async(&@) {	211	sub async(&@) {
200	my $pid = new Coro @_;	212	my $coro = new Coro @_;
201	$pid->ready;	213	$coro->ready;
202	$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
203	}	274	}
204		275
205	=item schedule	276	=item schedule
206		277
207	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
…		…
220	# wake up sleeping coroutine	291	# wake up sleeping coroutine
221	$current->ready;	292	$current->ready;
222	undef $current;	293	undef $current;
223	};	294	};
224		295
225	# call schedule until event occured.	296	# call schedule until event occurred.
226	# in case we are woken up for other reasons	297	# in case we are woken up for other reasons
227	# (current still defined), loop.	298	# (current still defined), loop.
228	Coro::schedule while $current;	299	Coro::schedule while $current;
229	}	300	}
230		301
231	=item cede	302	=item cede
232		303
233	"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
234	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
235	current "timeslice" to other coroutines of the same or higher priority.	306	current "timeslice" to other coroutines of the same or higher priority.
		307
		308	Returns true if at least one coroutine switch has happened.
		309
		310	=item Coro::cede_notself
		311
		312	Works like cede, but is not exported by default and will cede to any
		313	coroutine, regardless of priority, once.
		314
		315	Returns true if at least one coroutine switch has happened.
236		316
237	=item terminate [arg...]	317	=item terminate [arg...]
238		318
239	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>).
240		320
…		…
259	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
260	automatically terminates as if C<terminate> with the returned values were	340	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	341	called. To make the coroutine run you must first put it into the ready queue
262	by calling the ready method.	342	by calling the ready method.
263		343
264	Calling C<exit> in a coroutine will not work correctly, so do not do that.	344	See C<async> for additional discussion.
265		345
266	=cut	346	=cut
267		347
268	sub _run_coro {	348	sub _run_coro {
269	terminate &{+shift};	349	terminate &{+shift};
…		…
286	Return wether the coroutine is currently the ready queue or not,	366	Return wether the coroutine is currently the ready queue or not,
287		367
288	=item $coroutine->cancel (arg...)	368	=item $coroutine->cancel (arg...)
289		369
290	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
291	status (default: the empty list).	371	status (default: the empty list). Never returns if the coroutine is the
		372	current coroutine.
292		373
293	=cut	374	=cut
294		375
295	sub cancel {	376	sub cancel {
296	my $self = shift;	377	my $self = shift;
297	$self->{status} = [@_];	378	$self->{status} = [@_];
		379
		380	if ($current == $self) {
298	push @destroy, $self;	381	push @destroy, $self;
299	$manager->ready;	382	$manager->ready;
300	&schedule if $current == $self;	383	&schedule while 1;
		384	} else {
		385	$self->_cancel;
		386	}
301	}	387	}
302		388
303	=item $coroutine->join	389	=item $coroutine->join
304		390
305	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
…		…
308		394
309	=cut	395	=cut
310		396
311	sub join {	397	sub join {
312	my $self = shift;	398	my $self = shift;
		399
313	unless ($self->{status}) {	400	unless ($self->{status}) {
314	push @{$self->{join}}, $current;	401	my $current = $current;
315	&schedule;	402
		403	push @{$self->{destroy_cb}}, sub {
		404	$current->ready;
		405	undef $current;
		406	};
		407
		408	&schedule while $current;
316	}	409	}
		410
317	wantarray ? @{$self->{status}} : $self->{status}[0];	411	wantarray ? @{$self->{status}} : $self->{status}[0];
		412	}
		413
		414	=item $coroutine->on_destroy (\&cb)
		415
		416	Registers a callback that is called when this coroutine gets destroyed,
		417	but before it is joined. The callback gets passed the terminate arguments,
		418	if any.
		419
		420	=cut
		421
		422	sub on_destroy {
		423	my ($self, $cb) = @_;
		424
		425	push @{ $self->{destroy_cb} }, $cb;
318	}	426	}
319		427
320	=item $oldprio = $coroutine->prio ($newprio)	428	=item $oldprio = $coroutine->prio ($newprio)
321		429
322	Sets (or gets, if the argument is missing) the priority of the	430	Sets (or gets, if the argument is missing) the priority of the
…		…
364	=over 4	472	=over 4
365		473
366	=item Coro::nready	474	=item Coro::nready
367		475
368	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,
369	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
370	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,
371	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
372	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
373		515
374	=item unblock_sub { ... }	516	=item unblock_sub { ... }
375		517
376	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,
377	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
378	immediately without blocking, returning nothing, while the original code	520	immediately without blocking, returning nothing, while the original code
379	ref will be called (with parameters) from within its own coroutine.	521	ref will be called (with parameters) from within its own coroutine.
380		522
381	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
382	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
383	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,
384	otherwise you might suffer from crashes or worse.	526	otherwise you might suffer from crashes or worse.
385		527
386	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
…		…
391	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
392	creating event callbacks that want to block.	534	creating event callbacks that want to block.
393		535
394	=cut	536	=cut
395		537
396	our @unblock_pool;
397	our @unblock_queue;	538	our @unblock_queue;
398	our $UNBLOCK_POOL_SIZE = 2;
399		539
400	sub unblock_handler_ {	540	# we create a special coro because we want to cede,
401	while () {	541	# to reduce pressure on the coro pool (because most callbacks
402	my ($cb, @arg) = @{ delete $Coro::current->{arg} };	542	# return immediately and can be reused) and because we cannot cede
403	$cb->(@arg);	543	# 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 {	544	our $unblock_scheduler = new Coro sub {
412	while () {	545	while () {
413	while (my $cb = pop @unblock_queue) {	546	while (my $cb = pop @unblock_queue) {
414	my $handler = (pop @unblock_pool or new Coro \&unblock_handler_);	547	# this is an inlined copy of async_pool
415	$handler->{arg} = $cb;	548	my $coro = (pop @async_pool) \|\| new Coro \&pool_handler;
		549
		550	$coro->{_invoke} = $cb;
416	$handler->ready;	551	$coro->ready;
417	cede;	552	cede; # for short-lived callbacks, this reduces pressure on the coro pool
418	}	553	}
419		554	schedule; # sleep well
420	schedule;
421	}	555	}
422	};	556	};
		557	$unblock_scheduler->desc ("[unblock_sub scheduler]");
423		558
424	sub unblock_sub(&) {	559	sub unblock_sub(&) {
425	my $cb = shift;	560	my $cb = shift;
426		561
427	sub {	562	sub {
428	push @unblock_queue, [$cb, @_];	563	unshift @unblock_queue, [$cb, @_];
429	$unblock_scheduler->ready;	564	$unblock_scheduler->ready;
430	}	565	}
431	}	566	}
432		567
433	=back	568	=back
…		…
440		575
441	- 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
442	destruction. very bad things might happen otherwise (usually segfaults).	577	destruction. very bad things might happen otherwise (usually segfaults).
443		578
444	- 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
445	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
446	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
447	this).	582	this).
448		583
449	=head1 SEE ALSO	584	=head1 SEE ALSO
450		585

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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 1.139 by root, Thu Sep 27 15:52:30 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 1.139 by root, Thu Sep 27 15:52:30 2007 UTC