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

Comparing cvsroot/Coro/Coro.pm (file contents):
Revision 1.121 by root, Fri Apr 13 12:56:55 2007 UTC vs.
Revision 1.220 by root, Sun Nov 16 11:12:57 2008 UTC

…		…
2		2
3	Coro - coroutine process abstraction	3	Coro - coroutine process abstraction
4		4
5	=head1 SYNOPSIS	5	=head1 SYNOPSIS
6		6
7	use Coro;	7	use Coro;
8		8
9	async {	9	async {
10	# some asynchronous thread of execution	10	# some asynchronous thread of execution
		11	print "2\n";
		12	cede; # yield back to main
		13	print "4\n";
11	};	14	};
12		15	print "1\n";
13	# alternatively create an async coroutine like this:	16	cede; # yield to coroutine
14		17	print "3\n";
15	sub some_func : Coro {	18	cede; # and again
16	# some more async code	19
17	}	20	# use locking
18		21	use Coro::Semaphore;
19	cede;	22	my $lock = new Coro::Semaphore;
		23	my $locked;
		24
		25	$lock->down;
		26	$locked = 1;
		27	$lock->up;
20		28
21	=head1 DESCRIPTION	29	=head1 DESCRIPTION
22		30
23	This module collection manages coroutines. Coroutines are similar	31	This module collection manages coroutines. Coroutines are similar to
24	to threads but don't run in parallel at the same time even on SMP	32	threads but don't (in general) run in parallel at the same time even
25	machines. The specific flavor of coroutine use din this module also	33	on SMP machines. The specific flavor of coroutine used in this module
26	guarentees you that it will not switch between coroutines unless	34	also guarantees you that it will not switch between coroutines unless
27	necessary, at easily-identified points in your program, so locking and	35	necessary, at easily-identified points in your program, so locking and
28	parallel access are rarely an issue, making coroutine programming much	36	parallel access are rarely an issue, making coroutine programming much
29	safer than threads programming.	37	safer and easier than threads programming.
30		38
31	(Perl, however, does not natively support real threads but instead does a	39	Unlike a normal perl program, however, coroutines allow you to have
32	very slow and memory-intensive emulation of processes using threads. This	40	multiple running interpreters that share data, which is especially useful
33	is a performance win on Windows machines, and a loss everywhere else).	41	to code pseudo-parallel processes and for event-based programming, such as
		42	multiple HTTP-GET requests running concurrently. See L<Coro::AnyEvent> to
		43	learn more.
		44
		45	Coroutines are also useful because Perl has no support for threads (the so
		46	called "threads" that perl offers are nothing more than the (bad) process
		47	emulation coming from the Windows platform: On standard operating systems
		48	they serve no purpose whatsoever, except by making your programs slow and
		49	making them use a lot of memory. Best disable them when building perl, or
		50	aks your software vendor/distributor to do it for you).
34		51
35	In this module, coroutines are defined as "callchain + lexical variables +	52	In this module, coroutines are defined as "callchain + lexical variables +
36	@_ + $_ + $@ + $/ + C stack), that is, a coroutine has its own callchain,	53	@_ + $_ + $@ + $/ + C stack), that is, a coroutine has its own callchain,
37	its own set of lexicals and its own set of perls most important global	54	its own set of lexicals and its own set of perls most important global
38	variables.	55	variables (see L<Coro::State> for more configuration).
39		56
40	=cut	57	=cut
41		58
42	package Coro;	59	package Coro;
43		60
44	use strict;	61	use strict qw(vars subs);
45	no warnings "uninitialized";	62	no warnings "uninitialized";
46		63
47	use Coro::State;	64	use Coro::State;
48		65
49	use base qw(Coro::State Exporter);	66	use base qw(Coro::State Exporter);
50		67
51	our $idle; # idle handler	68	our $idle; # idle handler
52	our $main; # main coroutine	69	our $main; # main coroutine
53	our $current; # current coroutine	70	our $current; # current coroutine
54		71
55	our $VERSION = '3.56';	72	our $VERSION = 5.0;
56		73
57	our @EXPORT = qw(async async_pool cede schedule terminate current unblock_sub);	74	our @EXPORT = qw(async async_pool cede schedule terminate current unblock_sub);
58	our %EXPORT_TAGS = (	75	our %EXPORT_TAGS = (
59	prio => [qw(PRIO_MAX PRIO_HIGH PRIO_NORMAL PRIO_LOW PRIO_IDLE PRIO_MIN)],	76	prio => [qw(PRIO_MAX PRIO_HIGH PRIO_NORMAL PRIO_LOW PRIO_IDLE PRIO_MIN)],
60	);	77	);
61	our @EXPORT_OK = (@{$EXPORT_TAGS{prio}}, qw(nready));	78	our @EXPORT_OK = (@{$EXPORT_TAGS{prio}}, qw(nready));
62		79
63	{
64	my @async;
65	my $init;
66
67	# this way of handling attributes simply is NOT scalable ;()
68	sub import {
69	no strict 'refs';
70
71	Coro->export_to_level (1, @_);
72
73	my $old = *{(caller)[0]."::MODIFY_CODE_ATTRIBUTES"}{CODE};
74	*{(caller)[0]."::MODIFY_CODE_ATTRIBUTES"} = sub {
75	my ($package, $ref) = (shift, shift);
76	my @attrs;
77	for (@_) {
78	if ($_ eq "Coro") {
79	push @async, $ref;
80	unless ($init++) {
81	eval q{
82	sub INIT {
83	&async(pop @async) while @async;
84	}
85	};
86	}
87	} else {
88	push @attrs, $_;
89	}
90	}
91	return $old ? $old->($package, $ref, @attrs) : @attrs;
92	};
93	}
94
95	}
96
97	=over 4	80	=over 4
98		81
99	=item $main	82	=item $Coro::main
100		83
101	This coroutine represents the main program.	84	This variable stores the coroutine object that represents the main
		85	program. While you cna C<ready> it and do most other things you can do to
		86	coroutines, it is mainly useful to compare again C<$Coro::current>, to see
		87	whether you are running in the main program or not.
102		88
103	=cut	89	=cut
104		90
105	$main = new Coro;	91	# $main is now being initialised by Coro::State
106		92
107	=item $current (or as function: current)	93	=item $Coro::current
108		94
109	The current coroutine (the last coroutine switched to). The initial value	95	The coroutine object representing the current coroutine (the last
		96	coroutine that the Coro scheduler switched to). The initial value is
110	is C<$main> (of course).	97	C<$Coro::main> (of course).
111		98
112	This variable is B<strictly> I<read-only>. It is provided for performance	99	This variable is B<strictly> I<read-only>. You can take copies of the
113	reasons. If performance is not essentiel you are encouraged to use the	100	value stored in it and use it as any other coroutine object, but you must
114	C<Coro::current> function instead.	101	not otherwise modify the variable itself.
115		102
116	=cut	103	=cut
117		104
118	# maybe some other module used Coro::Specific before...
119	$main->{specific} = $current->{specific}
120	if $current;
121
122	_set_current $main;
123
124	sub current() { $current }	105	sub current() { $current } # [DEPRECATED]
125		106
126	=item $idle	107	=item $Coro::idle
127		108
128	A callback that is called whenever the scheduler finds no ready coroutines	109	This variable is mainly useful to integrate Coro into event loops. It is
129	to run. The default implementation prints "FATAL: deadlock detected" and	110	usually better to rely on L<Coro::AnyEvent> or LC<Coro::EV>, as this is
130	exits, because the program has no other way to continue.	111	pretty low-level functionality.
		112
		113	This variable stores a callback that is called whenever the scheduler
		114	finds no ready coroutines to run. The default implementation prints
		115	"FATAL: deadlock detected" and exits, because the program has no other way
		116	to continue.
131		117
132	This hook is overwritten by modules such as C<Coro::Timer> and	118	This hook is overwritten by modules such as C<Coro::Timer> and
133	C<Coro::Event> to wait on an external event that hopefully wake up a	119	C<Coro::AnyEvent> to wait on an external event that hopefully wake up a
134	coroutine so the scheduler can run it.	120	coroutine so the scheduler can run it.
135		121
		122	Note that the callback I<must not>, under any circumstances, block
		123	the current coroutine. Normally, this is achieved by having an "idle
		124	coroutine" that calls the event loop and then blocks again, and then
		125	readying that coroutine in the idle handler.
		126
		127	See L<Coro::Event> or L<Coro::AnyEvent> for examples of using this
		128	technique.
		129
136	Please note that if your callback recursively invokes perl (e.g. for event	130	Please note that if your callback recursively invokes perl (e.g. for event
137	handlers), then it must be prepared to be called recursively.	131	handlers), then it must be prepared to be called recursively itself.
138		132
139	=cut	133	=cut
140		134
141	$idle = sub {	135	$idle = sub {
142	require Carp;	136	require Carp;
…		…
149	# free coroutine data and mark as destructed	143	# free coroutine data and mark as destructed
150	$self->_destroy	144	$self->_destroy
151	or return;	145	or return;
152		146
153	# call all destruction callbacks	147	# call all destruction callbacks
154	$_->(@{$self->{status}})	148	$_->(@{$self->{_status}})
155	for @{(delete $self->{destroy_cb}) \|\| []};	149	for @{ delete $self->{_on_destroy} \|\| [] };
156	}	150	}
157		151
158	# this coroutine is necessary because a coroutine	152	# this coroutine is necessary because a coroutine
159	# cannot destroy itself.	153	# cannot destroy itself.
160	my @destroy;	154	my @destroy;
…		…
166	while @destroy;	160	while @destroy;
167		161
168	&schedule;	162	&schedule;
169	}	163	}
170	};	164	};
171		165	$manager->{desc} = "[coro manager]";
172	$manager->prio (PRIO_MAX);	166	$manager->prio (PRIO_MAX);
173		167
174	# static methods. not really.
175
176	=back	168	=back
177		169
178	=head2 STATIC METHODS	170	=head2 SIMPLE COROUTINE CREATION
179
180	Static methods are actually functions that operate on the current coroutine only.
181		171
182	=over 4	172	=over 4
183		173
184	=item async { ... } [@args...]	174	=item async { ... } [@args...]
185		175
186	Create a new asynchronous coroutine and return it's coroutine object	176	Create a new coroutine and return it's coroutine object (usually
187	(usually unused). When the sub returns the new coroutine is automatically	177	unused). The coroutine will be put into the ready queue, so
		178	it will start running automatically on the next scheduler run.
		179
		180	The first argument is a codeblock/closure that should be executed in the
		181	coroutine. When it returns argument returns the coroutine is automatically
188	terminated.	182	terminated.
189		183
		184	The remaining arguments are passed as arguments to the closure.
		185
		186	See the C<Coro::State::new> constructor for info about the coroutine
		187	environment in which coroutines are executed.
		188
190	Calling C<exit> in a coroutine will try to do the same as calling exit	189	Calling C<exit> in a coroutine will do the same as calling exit outside
191	outside the coroutine, but this is experimental. It is best not to rely on	190	the coroutine. Likewise, when the coroutine dies, the program will exit,
192	exit doing any cleanups or even not crashing.	191	just as it would in the main program.
193		192
194	When the coroutine dies, the program will exit, just as in the main	193	If you do not want that, you can provide a default C<die> handler, or
195	program.	194	simply avoid dieing (by use of C<eval>).
196		195
197	# create a new coroutine that just prints its arguments	196	Example: Create a new coroutine that just prints its arguments.
		197
198	async {	198	async {
199	print "@_\n";	199	print "@_\n";
200	} 1,2,3,4;	200	} 1,2,3,4;
201		201
202	=cut	202	=cut
…		…
208	}	208	}
209		209
210	=item async_pool { ... } [@args...]	210	=item async_pool { ... } [@args...]
211		211
212	Similar to C<async>, but uses a coroutine pool, so you should not call	212	Similar to C<async>, but uses a coroutine pool, so you should not call
213	terminate or join (although you are allowed to), and you get a coroutine	213	terminate or join on it (although you are allowed to), and you get a
214	that might have executed other code already (which can be good or bad :).	214	coroutine that might have executed other code already (which can be good
		215	or bad :).
215		216
		217	On the plus side, this function is faster than creating (and destroying)
		218	a completly new coroutine, so if you need a lot of generic coroutines in
		219	quick successsion, use C<async_pool>, not C<async>.
		220
216	Also, the block is executed in an C<eval> context and a warning will be	221	The code block is executed in an C<eval> context and a warning will be
217	issued in case of an exception instead of terminating the program, as	222	issued in case of an exception instead of terminating the program, as
218	C<async> does. As the coroutine is being reused, stuff like C<on_destroy>	223	C<async> does. As the coroutine is being reused, stuff like C<on_destroy>
219	will not work in the expected way, unless you call terminate or cancel,	224	will not work in the expected way, unless you call terminate or cancel,
220	which somehow defeats the purpose of pooling.	225	which somehow defeats the purpose of pooling (but is fine in the
		226	exceptional case).
221		227
222	The priority will be reset to C<0> after each job, otherwise the coroutine	228	The priority will be reset to C<0> after each run, tracing will be
223	will be re-used "as-is".	229	disabled, the description will be reset and the default output filehandle
		230	gets restored, so you can change all these. Otherwise the coroutine will
		231	be re-used "as-is": most notably if you change other per-coroutine global
		232	stuff such as C<$/> you I<must needs> revert that change, which is most
		233	simply done by using local as in: C<< local $/ >>.
224		234
225	The pool size is limited to 8 idle coroutines (this can be adjusted by	235	The idle pool size is limited to C<8> idle coroutines (this can be
226	changing $Coro::POOL_SIZE), and there can be as many non-idle coros as	236	adjusted by changing $Coro::POOL_SIZE), but there can be as many non-idle
227	required.	237	coros as required.
228		238
229	If you are concerned about pooled coroutines growing a lot because a	239	If you are concerned about pooled coroutines growing a lot because a
230	single C<async_pool> used a lot of stackspace you can e.g. C<async_pool {	240	single C<async_pool> used a lot of stackspace you can e.g. C<async_pool
231	terminate }> once per second or so to slowly replenish the pool.	241	{ terminate }> once per second or so to slowly replenish the pool. In
		242	addition to that, when the stacks used by a handler grows larger than 16kb
		243	(adjustable via $Coro::POOL_RSS) it will also be destroyed.
232		244
233	=cut	245	=cut
234		246
235	our $POOL_SIZE = 8;	247	our $POOL_SIZE = 8;
		248	our $POOL_RSS = 16 * 1024;
236	our @pool;	249	our @async_pool;
237		250
238	sub pool_handler {	251	sub pool_handler {
		252	my $cb;
		253
239	while () {	254	while () {
240	eval {	255	eval {
241	my ($cb, @arg) = @{ delete $current->{_invoke} or return };	256	while () {
242	$cb->(@arg);	257	_pool_1 $cb;
		258	&$cb;
		259	_pool_2 $cb;
		260	&schedule;
		261	}
243	};	262	};
		263
		264	if ($@) {
		265	last if $@ eq "\3async_pool terminate\2\n";
244	warn $@ if $@;	266	warn $@;
245		267	}
246	last if @pool >= $POOL_SIZE;
247	push @pool, $current;
248
249	$current->save (Coro::State::SAVE_DEF);
250	$current->prio (0);
251	schedule;
252	}	268	}
253	}	269	}
254		270
255	sub async_pool(&@) {	271	sub async_pool(&@) {
256	# this is also inlined into the unlock_scheduler	272	# this is also inlined into the unblock_scheduler
257	my $coro = (pop @pool or new Coro \&pool_handler);	273	my $coro = (pop @async_pool) \|\| new Coro \&pool_handler;
258		274
259	$coro->{_invoke} = [@_];	275	$coro->{_invoke} = [@_];
260	$coro->ready;	276	$coro->ready;
261		277
262	$coro	278	$coro
263	}	279	}
264		280
		281	=back
		282
		283	=head2 STATIC METHODS
		284
		285	Static methods are actually functions that operate on the current coroutine.
		286
		287	=over 4
		288
265	=item schedule	289	=item schedule
266		290
267	Calls the scheduler. Please note that the current coroutine will not be put	291	Calls the scheduler. The scheduler will find the next coroutine that is
		292	to be run from the ready queue and switches to it. The next coroutine
		293	to be run is simply the one with the highest priority that is longest
		294	in its ready queue. If there is no coroutine ready, it will clal the
		295	C<$Coro::idle> hook.
		296
		297	Please note that the current coroutine will I<not> be put into the ready
268	into the ready queue, so calling this function usually means you will	298	queue, so calling this function usually means you will never be called
269	never be called again unless something else (e.g. an event handler) calls	299	again unless something else (e.g. an event handler) calls C<< ->ready >>,
270	ready.	300	thus waking you up.
		301
		302	This makes C<schedule> I<the> generic method to use to block the current
		303	coroutine and wait for events: first you remember the current coroutine in
		304	a variable, then arrange for some callback of yours to call C<< ->ready
		305	>> on that once some event happens, and last you call C<schedule> to put
		306	yourself to sleep. Note that a lot of things can wake your coroutine up,
		307	so you need to check whether the event indeed happened, e.g. by storing the
		308	status in a variable.
271		309
272	The canonical way to wait on external events is this:	310	The canonical way to wait on external events is this:
273		311
274	{	312	{
275	# remember current coroutine	313	# remember current coroutine
…		…
280	# wake up sleeping coroutine	318	# wake up sleeping coroutine
281	$current->ready;	319	$current->ready;
282	undef $current;	320	undef $current;
283	};	321	};
284		322
285	# call schedule until event occured.	323	# call schedule until event occurred.
286	# in case we are woken up for other reasons	324	# in case we are woken up for other reasons
287	# (current still defined), loop.	325	# (current still defined), loop.
288	Coro::schedule while $current;	326	Coro::schedule while $current;
289	}	327	}
290		328
291	=item cede	329	=item cede
292		330
293	"Cede" to other coroutines. This function puts the current coroutine into the	331	"Cede" to other coroutines. This function puts the current coroutine into
294	ready queue and calls C<schedule>, which has the effect of giving up the	332	the ready queue and calls C<schedule>, which has the effect of giving
295	current "timeslice" to other coroutines of the same or higher priority.	333	up the current "timeslice" to other coroutines of the same or higher
		334	priority. Once your coroutine gets its turn again it will automatically be
		335	resumed.
296		336
297	Returns true if at least one coroutine switch has happened.	337	This function is often called C<yield> in other languages.
298		338
299	=item Coro::cede_notself	339	=item Coro::cede_notself
300		340
301	Works like cede, but is not exported by default and will cede to any	341	Works like cede, but is not exported by default and will cede to I<any>
302	coroutine, regardless of priority, once.	342	coroutine, regardless of priority. This is useful sometimes to ensure
303		343	progress is made.
304	Returns true if at least one coroutine switch has happened.
305		344
306	=item terminate [arg...]	345	=item terminate [arg...]
307		346
308	Terminates the current coroutine with the given status values (see L<cancel>).	347	Terminates the current coroutine with the given status values (see L<cancel>).
		348
		349	=item killall
		350
		351	Kills/terminates/cancels all coroutines except the currently running
		352	one. This is useful after a fork, either in the child or the parent, as
		353	usually only one of them should inherit the running coroutines.
		354
		355	Note that while this will try to free some of the main programs resources,
		356	you cannot free all of them, so if a coroutine that is not the main
		357	program calls this function, there will be some one-time resource leak.
309		358
310	=cut	359	=cut
311		360
312	sub terminate {	361	sub terminate {
313	$current->cancel (@_);	362	$current->cancel (@_);
314	}	363	}
315		364
		365	sub killall {
		366	for (Coro::State::list) {
		367	$_->cancel
		368	if $_ != $current && UNIVERSAL::isa $_, "Coro";
		369	}
		370	}
		371
316	=back	372	=back
317		373
318	# dynamic methods
319
320	=head2 COROUTINE METHODS	374	=head2 COROUTINE METHODS
321		375
322	These are the methods you can call on coroutine objects.	376	These are the methods you can call on coroutine objects (or to create
		377	them).
323		378
324	=over 4	379	=over 4
325		380
326	=item new Coro \&sub [, @args...]	381	=item new Coro \&sub [, @args...]
327		382
328	Create a new coroutine and return it. When the sub returns the coroutine	383	Create a new coroutine and return it. When the sub returns, the coroutine
329	automatically terminates as if C<terminate> with the returned values were	384	automatically terminates as if C<terminate> with the returned values were
330	called. To make the coroutine run you must first put it into the ready queue	385	called. To make the coroutine run you must first put it into the ready
331	by calling the ready method.	386	queue by calling the ready method.
332		387
333	See C<async> for additional discussion.	388	See C<async> and C<Coro::State::new> for additional info about the
		389	coroutine environment.
334		390
335	=cut	391	=cut
336		392
337	sub _run_coro {	393	sub _run_coro {
338	terminate &{+shift};	394	terminate &{+shift};
…		…
344	$class->SUPER::new (\&_run_coro, @_)	400	$class->SUPER::new (\&_run_coro, @_)
345	}	401	}
346		402
347	=item $success = $coroutine->ready	403	=item $success = $coroutine->ready
348		404
349	Put the given coroutine into the ready queue (according to it's priority)	405	Put the given coroutine into the end of its ready queue (there is one
350	and return true. If the coroutine is already in the ready queue, do nothing	406	queue for each priority) and return true. If the coroutine is already in
351	and return false.	407	the ready queue, do nothing and return false.
		408
		409	This ensures that the scheduler will resume this coroutine automatically
		410	once all the coroutines of higher priority and all coroutines of the same
		411	priority that were put into the ready queue earlier have been resumed.
352		412
353	=item $is_ready = $coroutine->is_ready	413	=item $is_ready = $coroutine->is_ready
354		414
355	Return wether the coroutine is currently the ready queue or not,	415	Return whether the coroutine is currently the ready queue or not,
356		416
357	=item $coroutine->cancel (arg...)	417	=item $coroutine->cancel (arg...)
358		418
359	Terminates the given coroutine and makes it return the given arguments as	419	Terminates the given coroutine and makes it return the given arguments as
360	status (default: the empty list). Never returns if the coroutine is the	420	status (default: the empty list). Never returns if the coroutine is the
…		…
362		422
363	=cut	423	=cut
364		424
365	sub cancel {	425	sub cancel {
366	my $self = shift;	426	my $self = shift;
367	$self->{status} = [@_];	427	$self->{_status} = [@_];
368		428
369	if ($current == $self) {	429	if ($current == $self) {
370	push @destroy, $self;	430	push @destroy, $self;
371	$manager->ready;	431	$manager->ready;
372	&schedule while 1;	432	&schedule while 1;
373	} else {	433	} else {
374	$self->_cancel;	434	$self->_cancel;
375	}	435	}
376	}	436	}
377		437
		438	=item $coroutine->throw ([$scalar])
		439
		440	If C<$throw> is specified and defined, it will be thrown as an exception
		441	inside the coroutine at the next convenient point in time (usually after
		442	it gains control at the next schedule/transfer/cede). Otherwise clears the
		443	exception object.
		444
		445	The exception object will be thrown "as is" with the specified scalar in
		446	C<$@>, i.e. if it is a string, no line number or newline will be appended
		447	(unlike with C<die>).
		448
		449	This can be used as a softer means than C<cancel> to ask a coroutine to
		450	end itself, although there is no guarantee that the exception will lead to
		451	termination, and if the exception isn't caught it might well end the whole
		452	program.
		453
		454	You might also think of C<throw> as being the moral equivalent of
		455	C<kill>ing a coroutine with a signal (in this case, a scalar).
		456
378	=item $coroutine->join	457	=item $coroutine->join
379		458
380	Wait until the coroutine terminates and return any values given to the	459	Wait until the coroutine terminates and return any values given to the
381	C<terminate> or C<cancel> functions. C<join> can be called multiple times	460	C<terminate> or C<cancel> functions. C<join> can be called concurrently
382	from multiple coroutine.	461	from multiple coroutines, and all will be resumed and given the status
		462	return once the C<$coroutine> terminates.
383		463
384	=cut	464	=cut
385		465
386	sub join {	466	sub join {
387	my $self = shift;	467	my $self = shift;
388		468
389	unless ($self->{status}) {	469	unless ($self->{_status}) {
390	my $current = $current;	470	my $current = $current;
391		471
392	push @{$self->{destroy_cb}}, sub {	472	push @{$self->{_on_destroy}}, sub {
393	$current->ready;	473	$current->ready;
394	undef $current;	474	undef $current;
395	};	475	};
396		476
397	&schedule while $current;	477	&schedule while $current;
398	}	478	}
399		479
400	wantarray ? @{$self->{status}} : $self->{status}[0];	480	wantarray ? @{$self->{_status}} : $self->{_status}[0];
401	}	481	}
402		482
403	=item $coroutine->on_destroy (\&cb)	483	=item $coroutine->on_destroy (\&cb)
404		484
405	Registers a callback that is called when this coroutine gets destroyed,	485	Registers a callback that is called when this coroutine gets destroyed,
406	but before it is joined. The callback gets passed the terminate arguments,	486	but before it is joined. The callback gets passed the terminate arguments,
407	if any.	487	if any, and I<must not> die, under any circumstances.
408		488
409	=cut	489	=cut
410		490
411	sub on_destroy {	491	sub on_destroy {
412	my ($self, $cb) = @_;	492	my ($self, $cb) = @_;
413		493
414	push @{ $self->{destroy_cb} }, $cb;	494	push @{ $self->{_on_destroy} }, $cb;
415	}	495	}
416		496
417	=item $oldprio = $coroutine->prio ($newprio)	497	=item $oldprio = $coroutine->prio ($newprio)
418		498
419	Sets (or gets, if the argument is missing) the priority of the	499	Sets (or gets, if the argument is missing) the priority of the
…		…
442	higher values mean lower priority, just as in unix).	522	higher values mean lower priority, just as in unix).
443		523
444	=item $olddesc = $coroutine->desc ($newdesc)	524	=item $olddesc = $coroutine->desc ($newdesc)
445		525
446	Sets (or gets in case the argument is missing) the description for this	526	Sets (or gets in case the argument is missing) the description for this
447	coroutine. This is just a free-form string you can associate with a coroutine.	527	coroutine. This is just a free-form string you can associate with a
		528	coroutine.
		529
		530	This method simply sets the C<< $coroutine->{desc} >> member to the given
		531	string. You can modify this member directly if you wish.
448		532
449	=cut	533	=cut
450		534
451	sub desc {	535	sub desc {
452	my $old = $_[0]{desc};	536	my $old = $_[0]{desc};
…		…
461	=over 4	545	=over 4
462		546
463	=item Coro::nready	547	=item Coro::nready
464		548
465	Returns the number of coroutines that are currently in the ready state,	549	Returns the number of coroutines that are currently in the ready state,
466	i.e. that can be swicthed to. The value C<0> means that the only runnable	550	i.e. that can be switched to by calling C<schedule> directory or
		551	indirectly. The value C<0> means that the only runnable coroutine is the
467	coroutine is the currently running one, so C<cede> would have no effect,	552	currently running one, so C<cede> would have no effect, and C<schedule>
468	and C<schedule> would cause a deadlock unless there is an idle handler	553	would cause a deadlock unless there is an idle handler that wakes up some
469	that wakes up some coroutines.	554	coroutines.
470		555
471	=item my $guard = Coro::guard { ... }	556	=item my $guard = Coro::guard { ... }
472		557
473	This creates and returns a guard object. Nothing happens until the object	558	This creates and returns a guard object. Nothing happens until the object
474	gets destroyed, in which case the codeblock given as argument will be	559	gets destroyed, in which case the codeblock given as argument will be
…		…
503		588
504		589
505	=item unblock_sub { ... }	590	=item unblock_sub { ... }
506		591
507	This utility function takes a BLOCK or code reference and "unblocks" it,	592	This utility function takes a BLOCK or code reference and "unblocks" it,
508	returning the new coderef. This means that the new coderef will return	593	returning a new coderef. Unblocking means that calling the new coderef
509	immediately without blocking, returning nothing, while the original code	594	will return immediately without blocking, returning nothing, while the
510	ref will be called (with parameters) from within its own coroutine.	595	original code ref will be called (with parameters) from within another
		596	coroutine.
511		597
512	The reason this fucntion exists is that many event libraries (such as the	598	The reason this function exists is that many event libraries (such as the
513	venerable L<Event\|Event> module) are not coroutine-safe (a weaker form	599	venerable L<Event\|Event> module) are not coroutine-safe (a weaker form
514	of thread-safety). This means you must not block within event callbacks,	600	of thread-safety). This means you must not block within event callbacks,
515	otherwise you might suffer from crashes or worse.	601	otherwise you might suffer from crashes or worse. The only event library
		602	currently known that is safe to use without C<unblock_sub> is L<EV>.
516		603
517	This function allows your callbacks to block by executing them in another	604	This function allows your callbacks to block by executing them in another
518	coroutine where it is safe to block. One example where blocking is handy	605	coroutine where it is safe to block. One example where blocking is handy
519	is when you use the L<Coro::AIO\|Coro::AIO> functions to save results to	606	is when you use the L<Coro::AIO\|Coro::AIO> functions to save results to
520	disk.	607	disk, for example.
521		608
522	In short: simply use C<unblock_sub { ... }> instead of C<sub { ... }> when	609	In short: simply use C<unblock_sub { ... }> instead of C<sub { ... }> when
523	creating event callbacks that want to block.	610	creating event callbacks that want to block.
		611
		612	If your handler does not plan to block (e.g. simply sends a message to
		613	another coroutine, or puts some other coroutine into the ready queue),
		614	there is no reason to use C<unblock_sub>.
		615
		616	Note that you also need to use C<unblock_sub> for any other callbacks that
		617	are indirectly executed by any C-based event loop. For example, when you
		618	use a module that uses L<AnyEvent> (and you use L<Coro::AnyEvent>) and it
		619	provides callbacks that are the result of some event callback, then you
		620	must not block either, or use C<unblock_sub>.
524		621
525	=cut	622	=cut
526		623
527	our @unblock_queue;	624	our @unblock_queue;
528		625
529	# we create a special coro because we want to cede,	626	# we create a special coro because we want to cede,
530	# to reduce pressure on the coro pool (because most callbacks	627	# to reduce pressure on the coro pool (because most callbacks
531	# return immediately and can be reused) and because we cannot cede	628	# return immediately and can be reused) and because we cannot cede
532	# inside an event callback.	629	# inside an event callback.
533	our $unblock_scheduler = async {	630	our $unblock_scheduler = new Coro sub {
534	while () {	631	while () {
535	while (my $cb = pop @unblock_queue) {	632	while (my $cb = pop @unblock_queue) {
536	# this is an inlined copy of async_pool	633	# this is an inlined copy of async_pool
537	my $coro = (pop @pool or new Coro \&pool_handler);	634	my $coro = (pop @async_pool) \|\| new Coro \&pool_handler;
538		635
539	$coro->{_invoke} = $cb;	636	$coro->{_invoke} = $cb;
540	$coro->ready;	637	$coro->ready;
541	cede; # for short-lived callbacks, this reduces pressure on the coro pool	638	cede; # for short-lived callbacks, this reduces pressure on the coro pool
542	}	639	}
543	schedule; # sleep well	640	schedule; # sleep well
544	}	641	}
545	};	642	};
		643	$unblock_scheduler->{desc} = "[unblock_sub scheduler]";
546		644
547	sub unblock_sub(&) {	645	sub unblock_sub(&) {
548	my $cb = shift;	646	my $cb = shift;
549		647
550	sub {	648	sub {
…		…
559		657
560	1;	658	1;
561		659
562	=head1 BUGS/LIMITATIONS	660	=head1 BUGS/LIMITATIONS
563		661
564	- you must make very sure that no coro is still active on global	662	=over 4
565	destruction. very bad things might happen otherwise (usually segfaults).
566		663
		664	=item fork with pthread backend
		665
		666	When Coro is compiled using the pthread backend (which isn't recommended
		667	but required on many BSDs as their libcs are completely broken), then
		668	coroutines will not survive a fork. There is no known workaround except to
		669	fix your libc and use a saner backend.
		670
		671	=item perl process emulation ("threads")
		672
567	- this module is not thread-safe. You should only ever use this module	673	This module is not perl-pseudo-thread-safe. You should only ever use this
568	from the same thread (this requirement might be losened in the future	674	module from the same thread (this requirement might be removed in the
569	to allow per-thread schedulers, but Coro::State does not yet allow	675	future to allow per-thread schedulers, but Coro::State does not yet allow
570	this).	676	this). I recommend disabling thread support and using processes, as having
		677	the windows process emulation enabled under unix roughly halves perl
		678	performance, even when not used.
		679
		680	=item coroutine switching not signal safe
		681
		682	You must not switch to another coroutine from within a signal handler
		683	(only relevant with %SIG - most event libraries provide safe signals).
		684
		685	That means you I<MUST NOT> call any fucntion that might "block" the
		686	current coroutine - C<cede>, C<schedule> C<< Coro::Semaphore->down >> or
		687	anything that calls those. Everything else, including calling C<ready>,
		688	works.
		689
		690	=back
		691
571		692
572	=head1 SEE ALSO	693	=head1 SEE ALSO
573		694
		695	Event-Loop integration: L<Coro::AnyEvent>, L<Coro::EV>, L<Coro::Event>.
		696
		697	Debugging: L<Coro::Debug>.
		698
574	Support/Utility: L<Coro::Cont>, L<Coro::Specific>, L<Coro::State>, L<Coro::Util>.	699	Support/Utility: L<Coro::Specific>, L<Coro::Util>.
575		700
576	Locking/IPC: L<Coro::Signal>, L<Coro::Channel>, L<Coro::Semaphore>, L<Coro::SemaphoreSet>, L<Coro::RWLock>.	701	Locking/IPC: L<Coro::Signal>, L<Coro::Channel>, L<Coro::Semaphore>, L<Coro::SemaphoreSet>, L<Coro::RWLock>.
577		702
578	Event/IO: L<Coro::Timer>, L<Coro::Event>, L<Coro::Handle>, L<Coro::Socket>, L<Coro::Select>.	703	IO/Timers: L<Coro::Timer>, L<Coro::Handle>, L<Coro::Socket>, L<Coro::AIO>.
579		704
580	Embedding: L<Coro:MakeMaker>	705	Compatibility: L<Coro::LWP>, L<Coro::BDB>, L<Coro::Storable>, L<Coro::Select>.
		706
		707	XS API: L<Coro::MakeMaker>.
		708
		709	Low level Configuration, Coroutine Environment: L<Coro::State>.
581		710
582	=head1 AUTHOR	711	=head1 AUTHOR
583		712
584	Marc Lehmann <schmorp@schmorp.de>	713	Marc Lehmann <schmorp@schmorp.de>
585	http://home.schmorp.de/	714	http://home.schmorp.de/

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Revision 1.220 by root, Sun Nov 16 11:12:57 2008 UTC