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

Comparing Coro/Coro.pm (file contents):
Revision 1.97 by root, Mon Dec 4 13:47:56 2006 UTC vs.
Revision 1.145 by root, Wed Oct 3 16:03:17 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 = '3.01';	55	our $VERSION = '4.0';
47		56
48	our @EXPORT = qw(async cede schedule terminate current unblock_sub);	57	our @EXPORT = qw(async async_pool cede schedule terminate current unblock_sub);
49	our %EXPORT_TAGS = (	58	our %EXPORT_TAGS = (
50	prio => [qw(PRIO_MAX PRIO_HIGH PRIO_NORMAL PRIO_LOW PRIO_IDLE PRIO_MIN)],	59	prio => [qw(PRIO_MAX PRIO_HIGH PRIO_NORMAL PRIO_LOW PRIO_IDLE PRIO_MIN)],
51	);	60	);
52	our @EXPORT_OK = (@{$EXPORT_TAGS{prio}}, qw(nready));	61	our @EXPORT_OK = (@{$EXPORT_TAGS{prio}}, qw(nready));
53		62
…		…
99		108
100	The current coroutine (the last coroutine switched to). The initial value	109	The current coroutine (the last coroutine switched to). The initial value
101	is C<$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 }
…		…
132	$idle = sub {	143	$idle = sub {
133	require Carp;	144	require Carp;
134	Carp::croak ("FATAL: deadlock detected");	145	Carp::croak ("FATAL: deadlock detected");
135	};	146	};
136		147
		148	sub _cancel {
		149	my ($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	}
		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, otherwise the coroutine
		225	will be re-used "as-is".
		226
		227	The pool size is limited to 8 idle coroutines (this can be adjusted by
		228	changing $Coro::POOL_SIZE), and there can be as many non-idle coros as
		229	required.
		230
		231	If you are concerned about pooled coroutines growing a lot because a
		232	single C<async_pool> used a lot of stackspace you can e.g. C<async_pool
		233	{ terminate }> once per second or so to slowly replenish the pool. In
		234	addition to that, when the stacks used by a handler grows larger than 16kb
		235	(adjustable with $Coro::POOL_RSS) it will also exit.
		236
		237	=cut
		238
		239	our $POOL_SIZE = 8;
		240	our $POOL_RSS = 16 * 1024;
		241	our @async_pool;
		242
		243	sub pool_handler {
		244	my $cb;
		245
		246	while () {
		247	eval {
		248	while () {
		249	_pool_1 $cb;
		250	&$cb;
		251	_pool_2 $cb;
		252	&schedule;
		253	}
		254	};
		255
		256	last if $@ eq "\3terminate\2\n";
		257	warn $@ if $@;
		258	}
		259	}
		260
		261	sub async_pool(&@) {
		262	# this is also inlined into the unlock_scheduler
		263	my $coro = (pop @async_pool) \|\| new Coro \&pool_handler;
		264
		265	$coro->{_invoke} = [@_];
		266	$coro->ready;
		267
		268	$coro
194	}	269	}
195		270
196	=item schedule	271	=item schedule
197		272
198	Calls the scheduler. Please note that the current coroutine will not be put	273	Calls the scheduler. Please note that the current coroutine will not be put
…		…
211	# wake up sleeping coroutine	286	# wake up sleeping coroutine
212	$current->ready;	287	$current->ready;
213	undef $current;	288	undef $current;
214	};	289	};
215		290
216	# call schedule until event occured.	291	# call schedule until event occurred.
217	# in case we are woken up for other reasons	292	# in case we are woken up for other reasons
218	# (current still defined), loop.	293	# (current still defined), loop.
219	Coro::schedule while $current;	294	Coro::schedule while $current;
220	}	295	}
221		296
…		…
223		298
224	"Cede" to other coroutines. This function puts the current coroutine into the	299	"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	300	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.	301	current "timeslice" to other coroutines of the same or higher priority.
227		302
		303	Returns true if at least one coroutine switch has happened.
		304
		305	=item Coro::cede_notself
		306
		307	Works like cede, but is not exported by default and will cede to any
		308	coroutine, regardless of priority, once.
		309
		310	Returns true if at least one coroutine switch has happened.
		311
228	=item terminate [arg...]	312	=item terminate [arg...]
229		313
230	Terminates the current coroutine with the given status values (see L<cancel>).	314	Terminates the current coroutine with the given status values (see L<cancel>).
		315
		316	=item killall
		317
		318	Kills/terminates/cancels all coroutines except the currently running
		319	one. This is useful after a fork, either in the child or the parent, as
		320	usually only one of them should inherit the running coroutines.
231		321
232	=cut	322	=cut
233		323
234	sub terminate {	324	sub terminate {
235	$current->cancel (@_);	325	$current->cancel (@_);
		326	}
		327
		328	sub killall {
		329	for (Coro::State::list) {
		330	$_->cancel
		331	if $_ != $current && UNIVERSAL::isa $_, "Coro";
		332	}
236	}	333	}
237		334
238	=back	335	=back
239		336
240	# dynamic methods	337	# dynamic methods
…		…
250	Create a new coroutine and return it. When the sub returns the coroutine	347	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	348	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	349	called. To make the coroutine run you must first put it into the ready queue
253	by calling the ready method.	350	by calling the ready method.
254		351
255	Calling C<exit> in a coroutine will not work correctly, so do not do that.	352	See C<async> and C<Coro::State::new> for additional info about the
		353	coroutine environment.
256		354
257	=cut	355	=cut
258		356
259	sub _run_coro {	357	sub _run_coro {
260	terminate &{+shift};	358	terminate &{+shift};
…		…
277	Return wether the coroutine is currently the ready queue or not,	375	Return wether the coroutine is currently the ready queue or not,
278		376
279	=item $coroutine->cancel (arg...)	377	=item $coroutine->cancel (arg...)
280		378
281	Terminates the given coroutine and makes it return the given arguments as	379	Terminates the given coroutine and makes it return the given arguments as
282	status (default: the empty list).	380	status (default: the empty list). Never returns if the coroutine is the
		381	current coroutine.
283		382
284	=cut	383	=cut
285		384
286	sub cancel {	385	sub cancel {
287	my $self = shift;	386	my $self = shift;
288	$self->{status} = [@_];	387	$self->{_status} = [@_];
		388
		389	if ($current == $self) {
289	push @destroy, $self;	390	push @destroy, $self;
290	$manager->ready;	391	$manager->ready;
291	&schedule if $current == $self;	392	&schedule while 1;
		393	} else {
		394	$self->_cancel;
		395	}
292	}	396	}
293		397
294	=item $coroutine->join	398	=item $coroutine->join
295		399
296	Wait until the coroutine terminates and return any values given to the	400	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	401	C<terminate> or C<cancel> functions. C<join> can be called concurrently
298	from multiple coroutine.	402	from multiple coroutines.
299		403
300	=cut	404	=cut
301		405
302	sub join {	406	sub join {
303	my $self = shift;	407	my $self = shift;
		408
304	unless ($self->{status}) {	409	unless ($self->{_status}) {
305	push @{$self->{join}}, $current;	410	my $current = $current;
306	&schedule;	411
		412	push @{$self->{_on_destroy}}, sub {
		413	$current->ready;
		414	undef $current;
		415	};
		416
		417	&schedule while $current;
307	}	418	}
		419
308	wantarray ? @{$self->{status}} : $self->{status}[0];	420	wantarray ? @{$self->{_status}} : $self->{_status}[0];
		421	}
		422
		423	=item $coroutine->on_destroy (\&cb)
		424
		425	Registers a callback that is called when this coroutine gets destroyed,
		426	but before it is joined. The callback gets passed the terminate arguments,
		427	if any.
		428
		429	=cut
		430
		431	sub on_destroy {
		432	my ($self, $cb) = @_;
		433
		434	push @{ $self->{_on_destroy} }, $cb;
309	}	435	}
310		436
311	=item $oldprio = $coroutine->prio ($newprio)	437	=item $oldprio = $coroutine->prio ($newprio)
312		438
313	Sets (or gets, if the argument is missing) the priority of the	439	Sets (or gets, if the argument is missing) the priority of the
…		…
338	=item $olddesc = $coroutine->desc ($newdesc)	464	=item $olddesc = $coroutine->desc ($newdesc)
339		465
340	Sets (or gets in case the argument is missing) the description for this	466	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.	467	coroutine. This is just a free-form string you can associate with a coroutine.
342		468
		469	This method simply sets the C<< $coroutine->{desc} >> member to the given string. You
		470	can modify this member directly if you wish.
		471
343	=cut	472	=cut
344		473
345	sub desc {	474	sub desc {
346	my $old = $_[0]{desc};	475	my $old = $_[0]{desc};
347	$_[0]{desc} = $_[1] if @_ > 1;	476	$_[0]{desc} = $_[1] if @_ > 1;
…		…
355	=over 4	484	=over 4
356		485
357	=item Coro::nready	486	=item Coro::nready
358		487
359	Returns the number of coroutines that are currently in the ready state,	488	Returns the number of coroutines that are currently in the ready state,
360	i.e. that can be swicthed to. The value C<0> means that the only runnable	489	i.e. that can be switched to. The value C<0> means that the only runnable
361	coroutine is the currently running one, so C<cede> would have no effect,	490	coroutine is the currently running one, so C<cede> would have no effect,
362	and C<schedule> would cause a deadlock unless there is an idle handler	491	and C<schedule> would cause a deadlock unless there is an idle handler
363	that wakes up some coroutines.	492	that wakes up some coroutines.
		493
		494	=item my $guard = Coro::guard { ... }
		495
		496	This creates and returns a guard object. Nothing happens until the object
		497	gets destroyed, in which case the codeblock given as argument will be
		498	executed. This is useful to free locks or other resources in case of a
		499	runtime error or when the coroutine gets canceled, as in both cases the
		500	guard block will be executed. The guard object supports only one method,
		501	C<< ->cancel >>, which will keep the codeblock from being executed.
		502
		503	Example: set some flag and clear it again when the coroutine gets canceled
		504	or the function returns:
		505
		506	sub do_something {
		507	my $guard = Coro::guard { $busy = 0 };
		508	$busy = 1;
		509
		510	# do something that requires $busy to be true
		511	}
		512
		513	=cut
		514
		515	sub guard(&) {
		516	bless \(my $cb = $_[0]), "Coro::guard"
		517	}
		518
		519	sub Coro::guard::cancel {
		520	${$_[0]} = sub { };
		521	}
		522
		523	sub Coro::guard::DESTROY {
		524	${$_[0]}->();
		525	}
		526
364		527
365	=item unblock_sub { ... }	528	=item unblock_sub { ... }
366		529
367	This utility function takes a BLOCK or code reference and "unblocks" it,	530	This utility function takes a BLOCK or code reference and "unblocks" it,
368	returning the new coderef. This means that the new coderef will return	531	returning the new coderef. This means that the new coderef will return
369	immediately without blocking, returning nothing, while the original code	532	immediately without blocking, returning nothing, while the original code
370	ref will be called (with parameters) from within its own coroutine.	533	ref will be called (with parameters) from within its own coroutine.
371		534
372	The reason this fucntion exists is that many event libraries (such as the	535	The reason this function exists is that many event libraries (such as the
373	venerable L<Event\|Event> module) are not coroutine-safe (a weaker form	536	venerable L<Event\|Event> module) are not coroutine-safe (a weaker form
374	of thread-safety). This means you must not block within event callbacks,	537	of thread-safety). This means you must not block within event callbacks,
375	otherwise you might suffer from crashes or worse.	538	otherwise you might suffer from crashes or worse.
376		539
377	This function allows your callbacks to block by executing them in another	540	This function allows your callbacks to block by executing them in another
…		…
382	In short: simply use C<unblock_sub { ... }> instead of C<sub { ... }> when	545	In short: simply use C<unblock_sub { ... }> instead of C<sub { ... }> when
383	creating event callbacks that want to block.	546	creating event callbacks that want to block.
384		547
385	=cut	548	=cut
386		549
387	our @unblock_pool;
388	our @unblock_queue;	550	our @unblock_queue;
389	our $UNBLOCK_POOL_SIZE = 2;
390		551
391	sub unblock_handler_ {	552	# we create a special coro because we want to cede,
392	while () {	553	# to reduce pressure on the coro pool (because most callbacks
393	my ($cb, @arg) = @{ delete $Coro::current->{arg} };	554	# return immediately and can be reused) and because we cannot cede
394	$cb->(@arg);	555	# inside an event callback.
395
396	last if @unblock_pool >= $UNBLOCK_POOL_SIZE;
397	push @unblock_pool, $Coro::current;
398	schedule;
399	}
400	}
401
402	our $unblock_scheduler = async {	556	our $unblock_scheduler = new Coro sub {
403	while () {	557	while () {
404	while (my $cb = pop @unblock_queue) {	558	while (my $cb = pop @unblock_queue) {
405	my $handler = (pop @unblock_pool or new Coro \&unblock_handler_);	559	# this is an inlined copy of async_pool
406	$handler->{arg} = $cb;	560	my $coro = (pop @async_pool) \|\| new Coro \&pool_handler;
		561
		562	$coro->{_invoke} = $cb;
407	$handler->ready;	563	$coro->ready;
408	cede;	564	cede; # for short-lived callbacks, this reduces pressure on the coro pool
409	}	565	}
410		566	schedule; # sleep well
411	schedule;
412	}	567	}
413	};	568	};
		569	$unblock_scheduler->desc ("[unblock_sub scheduler]");
414		570
415	sub unblock_sub(&) {	571	sub unblock_sub(&) {
416	my $cb = shift;	572	my $cb = shift;
417		573
418	sub {	574	sub {
419	push @unblock_queue, [$cb, @_];	575	unshift @unblock_queue, [$cb, @_];
420	$unblock_scheduler->ready;	576	$unblock_scheduler->ready;
421	}	577	}
422	}	578	}
423		579
424	=back	580	=back
…		…
431		587
432	- you must make very sure that no coro is still active on global	588	- you must make very sure that no coro is still active on global
433	destruction. very bad things might happen otherwise (usually segfaults).	589	destruction. very bad things might happen otherwise (usually segfaults).
434		590
435	- this module is not thread-safe. You should only ever use this module	591	- this module is not thread-safe. You should only ever use this module
436	from the same thread (this requirement might be losened in the future	592	from the same thread (this requirement might be loosened in the future
437	to allow per-thread schedulers, but Coro::State does not yet allow	593	to allow per-thread schedulers, but Coro::State does not yet allow
438	this).	594	this).
439		595
440	=head1 SEE ALSO	596	=head1 SEE ALSO
441		597

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Comparing Coro/Coro.pm (file contents): Revision 1.97 by root, Mon Dec 4 13:47:56 2006 UTC vs. Revision 1.145 by root, Wed Oct 3 16:03:17 2007 UTC

Diff Legend

Comparing Coro/Coro.pm (file contents):
Revision 1.97 by root, Mon Dec 4 13:47:56 2006 UTC vs.
Revision 1.145 by root, Wed Oct 3 16:03:17 2007 UTC