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

Comparing Coro/Coro.pm (file contents):
Revision 1.129 by root, Wed Sep 19 22:33:08 2007 UTC vs.
Revision 1.191 by root, Sat May 31 12:10:55 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	my $lock = new Coro::Semaphore;
19	cede;	22	my $locked;
		23
		24	$lock->down;
		25	$locked = 1;
		26	$lock->up;
20		27
21	=head1 DESCRIPTION	28	=head1 DESCRIPTION
22		29
23	This module collection manages coroutines. Coroutines are similar	30	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	31	threads but don't (in general) run in parallel at the same time even
25	machines. The specific flavor of coroutine used in this module also	32	on SMP machines. The specific flavor of coroutine used in this module
26	guarantees you that it will not switch between coroutines unless	33	also guarantees you that it will not switch between coroutines unless
27	necessary, at easily-identified points in your program, so locking and	34	necessary, at easily-identified points in your program, so locking and
28	parallel access are rarely an issue, making coroutine programming much	35	parallel access are rarely an issue, making coroutine programming much
29	safer than threads programming.	36	safer and easier than threads programming.
30		37
31	(Perl, however, does not natively support real threads but instead does a	38	Unlike a normal perl program, however, coroutines allow you to have
32	very slow and memory-intensive emulation of processes using threads. This	39	multiple running interpreters that share data, which is especially useful
33	is a performance win on Windows machines, and a loss everywhere else).	40	to code pseudo-parallel processes and for event-based programming, such as
		41	multiple HTTP-GET requests running concurrently. See L<Coro::AnyEvent> to
		42	learn more.
		43
		44	Coroutines are also useful because Perl has no support for threads (the so
		45	called "threads" that perl offers are nothing more than the (bad) process
		46	emulation coming from the Windows platform: On standard operating systems
		47	they serve no purpose whatsoever, except by making your programs slow and
		48	making them use a lot of memory. Best disable them when building perl, or
		49	aks your software vendor/distributor to do it for you).
34		50
35	In this module, coroutines are defined as "callchain + lexical variables +	51	In this module, coroutines are defined as "callchain + lexical variables +
36	@_ + $_ + $@ + $/ + C stack), that is, a coroutine has its own callchain,	52	@_ + $_ + $@ + $/ + 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	53	its own set of lexicals and its own set of perls most important global
38	variables.	54	variables (see L<Coro::State> for more configuration).
39		55
40	=cut	56	=cut
41		57
42	package Coro;	58	package Coro;
43		59
…		…
50		66
51	our $idle; # idle handler	67	our $idle; # idle handler
52	our $main; # main coroutine	68	our $main; # main coroutine
53	our $current; # current coroutine	69	our $current; # current coroutine
54		70
55	our $VERSION = '3.7';	71	our $VERSION = 4.742;
56		72
57	our @EXPORT = qw(async async_pool cede schedule terminate current unblock_sub);	73	our @EXPORT = qw(async async_pool cede schedule terminate current unblock_sub);
58	our %EXPORT_TAGS = (	74	our %EXPORT_TAGS = (
59	prio => [qw(PRIO_MAX PRIO_HIGH PRIO_NORMAL PRIO_LOW PRIO_IDLE PRIO_MIN)],	75	prio => [qw(PRIO_MAX PRIO_HIGH PRIO_NORMAL PRIO_LOW PRIO_IDLE PRIO_MIN)],
60	);	76	);
61	our @EXPORT_OK = (@{$EXPORT_TAGS{prio}}, qw(nready));	77	our @EXPORT_OK = (@{$EXPORT_TAGS{prio}}, qw(nready));
62		78
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	79	=over 4
98		80
99	=item $main	81	=item $Coro::main
100		82
101	This coroutine represents the main program.	83	This variable stores the coroutine object that represents the main
		84	program. While you cna C<ready> it and do most other things you can do to
		85	coroutines, it is mainly useful to compare again C<$Coro::current>, to see
		86	wether you are running in the main program or not.
102		87
103	=cut	88	=cut
104		89
105	$main = new Coro;	90	$main = new Coro;
106		91
107	=item $current (or as function: current)	92	=item $Coro::current
108		93
109	The current coroutine (the last coroutine switched to). The initial value	94	The coroutine object representing the current coroutine (the last
		95	coroutine that the Coro scheduler switched to). The initial value is
110	is C<$main> (of course).	96	C<$main> (of course).
111		97
112	This variable is B<strictly> I<read-only>. It is provided for performance	98	This variable is B<strictly> I<read-only>. You can take copies of the
113	reasons. If performance is not essential you are encouraged to use the	99	value stored in it and use it as any other coroutine object, but you must
114	C<Coro::current> function instead.	100	not otherwise modify the variable itself.
115		101
116	=cut	102	=cut
		103
		104	$main->{desc} = "[main::]";
117		105
118	# maybe some other module used Coro::Specific before...	106	# maybe some other module used Coro::Specific before...
119	$main->{specific} = $current->{specific}	107	$main->{_specific} = $current->{_specific}
120	if $current;	108	if $current;
121		109
122	_set_current $main;	110	_set_current $main;
123		111
124	sub current() { $current }	112	sub current() { $current } # [DEPRECATED]
125		113
126	=item $idle	114	=item $Coro::idle
127		115
128	A callback that is called whenever the scheduler finds no ready coroutines	116	This variable is mainly useful to integrate Coro into event loops. It is
129	to run. The default implementation prints "FATAL: deadlock detected" and	117	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.	118	pretty low-level functionality.
		119
		120	This variable stores a callback that is called whenever the scheduler
		121	finds no ready coroutines to run. The default implementation prints
		122	"FATAL: deadlock detected" and exits, because the program has no other way
		123	to continue.
131		124
132	This hook is overwritten by modules such as C<Coro::Timer> and	125	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	126	C<Coro::AnyEvent> to wait on an external event that hopefully wake up a
134	coroutine so the scheduler can run it.	127	coroutine so the scheduler can run it.
135		128
		129	Note that the callback I<must not>, under any circumstances, block
		130	the current coroutine. Normally, this is achieved by having an "idle
		131	coroutine" that calls the event loop and then blocks again, and then
		132	readying that coroutine in the idle handler.
		133
		134	See L<Coro::Event> or L<Coro::AnyEvent> for examples of using this
		135	technique.
		136
136	Please note that if your callback recursively invokes perl (e.g. for event	137	Please note that if your callback recursively invokes perl (e.g. for event
137	handlers), then it must be prepared to be called recursively.	138	handlers), then it must be prepared to be called recursively itself.
138		139
139	=cut	140	=cut
140		141
141	$idle = sub {	142	$idle = sub {
142	require Carp;	143	require Carp;
…		…
149	# free coroutine data and mark as destructed	150	# free coroutine data and mark as destructed
150	$self->_destroy	151	$self->_destroy
151	or return;	152	or return;
152		153
153	# call all destruction callbacks	154	# call all destruction callbacks
154	$_->(@{$self->{status}})	155	$_->(@{$self->{_status}})
155	for @{(delete $self->{destroy_cb}) \|\| []};	156	for @{(delete $self->{_on_destroy}) \|\| []};
156	}	157	}
157		158
158	# this coroutine is necessary because a coroutine	159	# this coroutine is necessary because a coroutine
159	# cannot destroy itself.	160	# cannot destroy itself.
160	my @destroy;	161	my @destroy;
161	my $manager;	162	my $manager;
162		163
163	$manager = new Coro sub {	164	$manager = new Coro sub {
164	$current->desc ("[coro manager]");
165
166	while () {	165	while () {
167	(shift @destroy)->_cancel	166	(shift @destroy)->_cancel
168	while @destroy;	167	while @destroy;
169		168
170	&schedule;	169	&schedule;
171	}	170	}
172	};	171	};
173		172	$manager->desc ("[coro manager]");
174	$manager->prio (PRIO_MAX);	173	$manager->prio (PRIO_MAX);
175		174
176	# static methods. not really.
177
178	=back	175	=back
179		176
180	=head2 STATIC METHODS	177	=head2 SIMPLE COROUTINE CREATION
181
182	Static methods are actually functions that operate on the current coroutine only.
183		178
184	=over 4	179	=over 4
185		180
186	=item async { ... } [@args...]	181	=item async { ... } [@args...]
187		182
188	Create a new asynchronous coroutine and return it's coroutine object	183	Create a new coroutine and return it's coroutine object (usually
189	(usually unused). When the sub returns the new coroutine is automatically	184	unused). The coroutine will be put into the ready queue, so
		185	it will start running automatically on the next scheduler run.
		186
		187	The first argument is a codeblock/closure that should be executed in the
		188	coroutine. When it returns argument returns the coroutine is automatically
190	terminated.	189	terminated.
		190
		191	The remaining arguments are passed as arguments to the closure.
		192
		193	See the C<Coro::State::new> constructor for info about the coroutine
		194	environment in which coroutines are executed.
191		195
192	Calling C<exit> in a coroutine will do the same as calling exit outside	196	Calling C<exit> in a coroutine will do the same as calling exit outside
193	the coroutine. Likewise, when the coroutine dies, the program will exit,	197	the coroutine. Likewise, when the coroutine dies, the program will exit,
194	just as it would in the main program.	198	just as it would in the main program.
195		199
		200	If you do not want that, you can provide a default C<die> handler, or
		201	simply avoid dieing (by use of C<eval>).
		202
196	# create a new coroutine that just prints its arguments	203	Example: Create a new coroutine that just prints its arguments.
		204
197	async {	205	async {
198	print "@_\n";	206	print "@_\n";
199	} 1,2,3,4;	207	} 1,2,3,4;
200		208
201	=cut	209	=cut
…		…
207	}	215	}
208		216
209	=item async_pool { ... } [@args...]	217	=item async_pool { ... } [@args...]
210		218
211	Similar to C<async>, but uses a coroutine pool, so you should not call	219	Similar to C<async>, but uses a coroutine pool, so you should not call
212	terminate or join (although you are allowed to), and you get a coroutine	220	terminate or join on it (although you are allowed to), and you get a
213	that might have executed other code already (which can be good or bad :).	221	coroutine that might have executed other code already (which can be good
		222	or bad :).
214		223
		224	On the plus side, this function is faster than creating (and destroying)
		225	a completely new coroutine, so if you need a lot of generic coroutines in
		226	quick successsion, use C<async_pool>, not C<async>.
		227
215	Also, the block is executed in an C<eval> context and a warning will be	228	The code block is executed in an C<eval> context and a warning will be
216	issued in case of an exception instead of terminating the program, as	229	issued in case of an exception instead of terminating the program, as
217	C<async> does. As the coroutine is being reused, stuff like C<on_destroy>	230	C<async> does. As the coroutine is being reused, stuff like C<on_destroy>
218	will not work in the expected way, unless you call terminate or cancel,	231	will not work in the expected way, unless you call terminate or cancel,
219	which somehow defeats the purpose of pooling.	232	which somehow defeats the purpose of pooling (but is fine in the
		233	exceptional case).
220		234
221	The priority will be reset to C<0> after each job, otherwise the coroutine	235	The priority will be reset to C<0> after each run, tracing will be
222	will be re-used "as-is".	236	disabled, the description will be reset and the default output filehandle
		237	gets restored, so you can change all these. Otherwise the coroutine will
		238	be re-used "as-is": most notably if you change other per-coroutine global
		239	stuff such as C<$/> you I<must needs> to revert that change, which is most
		240	simply done by using local as in: C< local $/ >.
223		241
224	The pool size is limited to 8 idle coroutines (this can be adjusted by	242	The pool size is limited to C<8> idle coroutines (this can be adjusted by
225	changing $Coro::POOL_SIZE), and there can be as many non-idle coros as	243	changing $Coro::POOL_SIZE), and there can be as many non-idle coros as
226	required.	244	required.
227		245
228	If you are concerned about pooled coroutines growing a lot because a	246	If you are concerned about pooled coroutines growing a lot because a
229	single C<async_pool> used a lot of stackspace you can e.g. C<async_pool {	247	single C<async_pool> used a lot of stackspace you can e.g. C<async_pool
230	terminate }> once per second or so to slowly replenish the pool.	248	{ terminate }> once per second or so to slowly replenish the pool. In
		249	addition to that, when the stacks used by a handler grows larger than 16kb
		250	(adjustable via $Coro::POOL_RSS) it will also be destroyed.
231		251
232	=cut	252	=cut
233		253
234	our $POOL_SIZE = 8;	254	our $POOL_SIZE = 8;
		255	our $POOL_RSS = 16 * 1024;
235	our @pool;	256	our @async_pool;
236		257
237	sub pool_handler {	258	sub pool_handler {
		259	my $cb;
		260
238	while () {	261	while () {
239	$current->{desc} = "[async_pool]";
240
241	eval {	262	eval {
242	my ($cb, @arg) = @{ delete $current->{_invoke} or return };	263	while () {
243	$cb->(@arg);	264	_pool_1 $cb;
		265	&$cb;
		266	_pool_2 $cb;
		267	&schedule;
		268	}
244	};	269	};
		270
		271	last if $@ eq "\3async_pool terminate\2\n";
245	warn $@ if $@;	272	warn $@ if $@;
246
247	last if @pool >= $POOL_SIZE;
248
249	push @pool, $current;
250	$current->{desc} = "[async_pool idle]";
251	$current->save (Coro::State::SAVE_DEF);
252	$current->prio (0);
253	schedule;
254	}	273	}
255	}	274	}
256		275
257	sub async_pool(&@) {	276	sub async_pool(&@) {
258	# this is also inlined into the unlock_scheduler	277	# this is also inlined into the unlock_scheduler
259	my $coro = (pop @pool) \|\| new Coro \&pool_handler;;	278	my $coro = (pop @async_pool) \|\| new Coro \&pool_handler;
260		279
261	$coro->{_invoke} = [@_];	280	$coro->{_invoke} = [@_];
262	$coro->ready;	281	$coro->ready;
263		282
264	$coro	283	$coro
265	}	284	}
266		285
		286	=back
		287
		288	=head2 STATIC METHODS
		289
		290	Static methods are actually functions that operate on the current coroutine.
		291
		292	=over 4
		293
267	=item schedule	294	=item schedule
268		295
269	Calls the scheduler. Please note that the current coroutine will not be put	296	Calls the scheduler. The scheduler will find the next coroutine that is
		297	to be run from the ready queue and switches to it. The next coroutine
		298	to be run is simply the one with the highest priority that is longest
		299	in its ready queue. If there is no coroutine ready, it will clal the
		300	C<$Coro::idle> hook.
		301
		302	Please note that the current coroutine will I<not> be put into the ready
270	into the ready queue, so calling this function usually means you will	303	queue, so calling this function usually means you will never be called
271	never be called again unless something else (e.g. an event handler) calls	304	again unless something else (e.g. an event handler) calls C<< ->ready >>,
272	ready.	305	thus waking you up.
		306
		307	This makes C<schedule> I<the> generic method to use to block the current
		308	coroutine and wait for events: first you remember the current coroutine in
		309	a variable, then arrange for some callback of yours to call C<< ->ready
		310	>> on that once some event happens, and last you call C<schedule> to put
		311	yourself to sleep. Note that a lot of things can wake your coroutine up,
		312	so you need to check wether the event indeed happened, e.g. by storing the
		313	status in a variable.
273		314
274	The canonical way to wait on external events is this:	315	The canonical way to wait on external events is this:
275		316
276	{	317	{
277	# remember current coroutine	318	# remember current coroutine
…		…
290	Coro::schedule while $current;	331	Coro::schedule while $current;
291	}	332	}
292		333
293	=item cede	334	=item cede
294		335
295	"Cede" to other coroutines. This function puts the current coroutine into the	336	"Cede" to other coroutines. This function puts the current coroutine into
296	ready queue and calls C<schedule>, which has the effect of giving up the	337	the ready queue and calls C<schedule>, which has the effect of giving
297	current "timeslice" to other coroutines of the same or higher priority.	338	up the current "timeslice" to other coroutines of the same or higher
		339	priority. Once your coroutine gets its turn again it will automatically be
		340	resumed.
298		341
299	Returns true if at least one coroutine switch has happened.	342	This function is often called C<yield> in other languages.
300		343
301	=item Coro::cede_notself	344	=item Coro::cede_notself
302		345
303	Works like cede, but is not exported by default and will cede to any	346	Works like cede, but is not exported by default and will cede to I<any>
304	coroutine, regardless of priority, once.	347	coroutine, regardless of priority. This is useful sometimes to ensure
305		348	progress is made.
306	Returns true if at least one coroutine switch has happened.
307		349
308	=item terminate [arg...]	350	=item terminate [arg...]
309		351
310	Terminates the current coroutine with the given status values (see L<cancel>).	352	Terminates the current coroutine with the given status values (see L<cancel>).
		353
		354	=item killall
		355
		356	Kills/terminates/cancels all coroutines except the currently running
		357	one. This is useful after a fork, either in the child or the parent, as
		358	usually only one of them should inherit the running coroutines.
		359
		360	Note that while this will try to free some of the main programs resources,
		361	you cnanot free all of them, so if a coroutine that is not the main
		362	program calls this function, there will be some one-time resource leak.
311		363
312	=cut	364	=cut
313		365
314	sub terminate {	366	sub terminate {
315	$current->cancel (@_);	367	$current->cancel (@_);
316	}	368	}
317		369
		370	sub killall {
		371	for (Coro::State::list) {
		372	$_->cancel
		373	if $_ != $current && UNIVERSAL::isa $_, "Coro";
		374	}
		375	}
		376
318	=back	377	=back
319		378
320	# dynamic methods
321
322	=head2 COROUTINE METHODS	379	=head2 COROUTINE METHODS
323		380
324	These are the methods you can call on coroutine objects.	381	These are the methods you can call on coroutine objects (or to create
		382	them).
325		383
326	=over 4	384	=over 4
327		385
328	=item new Coro \&sub [, @args...]	386	=item new Coro \&sub [, @args...]
329		387
330	Create a new coroutine and return it. When the sub returns the coroutine	388	Create a new coroutine and return it. When the sub returns, the coroutine
331	automatically terminates as if C<terminate> with the returned values were	389	automatically terminates as if C<terminate> with the returned values were
332	called. To make the coroutine run you must first put it into the ready queue	390	called. To make the coroutine run you must first put it into the ready
333	by calling the ready method.	391	queue by calling the ready method.
334		392
335	See C<async> for additional discussion.	393	See C<async> and C<Coro::State::new> for additional info about the
		394	coroutine environment.
336		395
337	=cut	396	=cut
338		397
339	sub _run_coro {	398	sub _run_coro {
340	terminate &{+shift};	399	terminate &{+shift};
…		…
346	$class->SUPER::new (\&_run_coro, @_)	405	$class->SUPER::new (\&_run_coro, @_)
347	}	406	}
348		407
349	=item $success = $coroutine->ready	408	=item $success = $coroutine->ready
350		409
351	Put the given coroutine into the ready queue (according to it's priority)	410	Put the given coroutine into the end of its ready queue (there is one
352	and return true. If the coroutine is already in the ready queue, do nothing	411	queue for each priority) and return true. If the coroutine is already in
353	and return false.	412	the ready queue, do nothing and return false.
		413
		414	This ensures that the scheduler will resume this coroutine automatically
		415	once all the coroutines of higher priority and all coroutines of the same
		416	priority that were put into the ready queue earlier have been resumed.
354		417
355	=item $is_ready = $coroutine->is_ready	418	=item $is_ready = $coroutine->is_ready
356		419
357	Return wether the coroutine is currently the ready queue or not,	420	Return wether the coroutine is currently the ready queue or not,
358		421
…		…
364		427
365	=cut	428	=cut
366		429
367	sub cancel {	430	sub cancel {
368	my $self = shift;	431	my $self = shift;
369	$self->{status} = [@_];	432	$self->{_status} = [@_];
370		433
371	if ($current == $self) {	434	if ($current == $self) {
372	push @destroy, $self;	435	push @destroy, $self;
373	$manager->ready;	436	$manager->ready;
374	&schedule while 1;	437	&schedule while 1;
…		…
378	}	441	}
379		442
380	=item $coroutine->join	443	=item $coroutine->join
381		444
382	Wait until the coroutine terminates and return any values given to the	445	Wait until the coroutine terminates and return any values given to the
383	C<terminate> or C<cancel> functions. C<join> can be called multiple times	446	C<terminate> or C<cancel> functions. C<join> can be called concurrently
384	from multiple coroutine.	447	from multiple coroutines, and all will be resumed and given the status
		448	return once the C<$coroutine> terminates.
385		449
386	=cut	450	=cut
387		451
388	sub join {	452	sub join {
389	my $self = shift;	453	my $self = shift;
390		454
391	unless ($self->{status}) {	455	unless ($self->{_status}) {
392	my $current = $current;	456	my $current = $current;
393		457
394	push @{$self->{destroy_cb}}, sub {	458	push @{$self->{_on_destroy}}, sub {
395	$current->ready;	459	$current->ready;
396	undef $current;	460	undef $current;
397	};	461	};
398		462
399	&schedule while $current;	463	&schedule while $current;
400	}	464	}
401		465
402	wantarray ? @{$self->{status}} : $self->{status}[0];	466	wantarray ? @{$self->{_status}} : $self->{_status}[0];
403	}	467	}
404		468
405	=item $coroutine->on_destroy (\&cb)	469	=item $coroutine->on_destroy (\&cb)
406		470
407	Registers a callback that is called when this coroutine gets destroyed,	471	Registers a callback that is called when this coroutine gets destroyed,
408	but before it is joined. The callback gets passed the terminate arguments,	472	but before it is joined. The callback gets passed the terminate arguments,
409	if any.	473	if any, and I<must not> die, under any circumstances.
410		474
411	=cut	475	=cut
412		476
413	sub on_destroy {	477	sub on_destroy {
414	my ($self, $cb) = @_;	478	my ($self, $cb) = @_;
415		479
416	push @{ $self->{destroy_cb} }, $cb;	480	push @{ $self->{_on_destroy} }, $cb;
417	}	481	}
418		482
419	=item $oldprio = $coroutine->prio ($newprio)	483	=item $oldprio = $coroutine->prio ($newprio)
420		484
421	Sets (or gets, if the argument is missing) the priority of the	485	Sets (or gets, if the argument is missing) the priority of the
…		…
446	=item $olddesc = $coroutine->desc ($newdesc)	510	=item $olddesc = $coroutine->desc ($newdesc)
447		511
448	Sets (or gets in case the argument is missing) the description for this	512	Sets (or gets in case the argument is missing) the description for this
449	coroutine. This is just a free-form string you can associate with a coroutine.	513	coroutine. This is just a free-form string you can associate with a coroutine.
450		514
		515	This method simply sets the C<< $coroutine->{desc} >> member to the given string. You
		516	can modify this member directly if you wish.
		517
		518	=item $coroutine->throw ([$scalar])
		519
		520	If C<$throw> is specified and defined, it will be thrown as an exception
		521	inside the coroutine at the next convinient point in time (usually after
		522	it gains control at the next schedule/transfer/cede). Otherwise clears the
		523	exception object.
		524
		525	The exception object will be thrown "as is" with the specified scalar in
		526	C<$@>, i.e. if it is a string, no line number or newline will be appended
		527	(unlike with C<die>).
		528
		529	This can be used as a softer means than C<cancel> to ask a coroutine to
		530	end itself, although there is no guarentee that the exception will lead to
		531	termination, and if the exception isn't caught it might well end the whole
		532	program.
		533
451	=cut	534	=cut
452		535
453	sub desc {	536	sub desc {
454	my $old = $_[0]{desc};	537	my $old = $_[0]{desc};
455	$_[0]{desc} = $_[1] if @_ > 1;	538	$_[0]{desc} = $_[1] if @_ > 1;
…		…
463	=over 4	546	=over 4
464		547
465	=item Coro::nready	548	=item Coro::nready
466		549
467	Returns the number of coroutines that are currently in the ready state,	550	Returns the number of coroutines that are currently in the ready state,
468	i.e. that can be switched to. The value C<0> means that the only runnable	551	i.e. that can be switched to by calling C<schedule> directory or
		552	indirectly. The value C<0> means that the only runnable coroutine is the
469	coroutine is the currently running one, so C<cede> would have no effect,	553	currently running one, so C<cede> would have no effect, and C<schedule>
470	and C<schedule> would cause a deadlock unless there is an idle handler	554	would cause a deadlock unless there is an idle handler that wakes up some
471	that wakes up some coroutines.	555	coroutines.
472		556
473	=item my $guard = Coro::guard { ... }	557	=item my $guard = Coro::guard { ... }
474		558
475	This creates and returns a guard object. Nothing happens until the object	559	This creates and returns a guard object. Nothing happens until the object
476	gets destroyed, in which case the codeblock given as argument will be	560	gets destroyed, in which case the codeblock given as argument will be
…		…
505		589
506		590
507	=item unblock_sub { ... }	591	=item unblock_sub { ... }
508		592
509	This utility function takes a BLOCK or code reference and "unblocks" it,	593	This utility function takes a BLOCK or code reference and "unblocks" it,
510	returning the new coderef. This means that the new coderef will return	594	returning a new coderef. Unblocking means that calling the new coderef
511	immediately without blocking, returning nothing, while the original code	595	will return immediately without blocking, returning nothing, while the
512	ref will be called (with parameters) from within its own coroutine.	596	original code ref will be called (with parameters) from within another
		597	coroutine.
513		598
514	The reason this function exists is that many event libraries (such as the	599	The reason this function exists is that many event libraries (such as the
515	venerable L<Event\|Event> module) are not coroutine-safe (a weaker form	600	venerable L<Event\|Event> module) are not coroutine-safe (a weaker form
516	of thread-safety). This means you must not block within event callbacks,	601	of thread-safety). This means you must not block within event callbacks,
517	otherwise you might suffer from crashes or worse.	602	otherwise you might suffer from crashes or worse. The only event library
		603	currently known that is safe to use without C<unblock_sub> is L<EV>.
518		604
519	This function allows your callbacks to block by executing them in another	605	This function allows your callbacks to block by executing them in another
520	coroutine where it is safe to block. One example where blocking is handy	606	coroutine where it is safe to block. One example where blocking is handy
521	is when you use the L<Coro::AIO\|Coro::AIO> functions to save results to	607	is when you use the L<Coro::AIO\|Coro::AIO> functions to save results to
522	disk.	608	disk, for example.
523		609
524	In short: simply use C<unblock_sub { ... }> instead of C<sub { ... }> when	610	In short: simply use C<unblock_sub { ... }> instead of C<sub { ... }> when
525	creating event callbacks that want to block.	611	creating event callbacks that want to block.
		612
		613	If your handler does not plan to block (e.g. simply sends a message to
		614	another coroutine, or puts some other coroutine into the ready queue),
		615	there is no reason to use C<unblock_sub>.
		616
		617	Note that you also need to use C<unblock_sub> for any other callbacks that
		618	are indirectly executed by any C-based event loop. For example, when you
		619	use a module that uses L<AnyEvent> (and you use L<Coro::AnyEvent>) and it
		620	provides callbacks that are the result of some event callback, then you
		621	must not block either, or use C<unblock_sub>.
526		622
527	=cut	623	=cut
528		624
529	our @unblock_queue;	625	our @unblock_queue;
530		626
531	# we create a special coro because we want to cede,	627	# we create a special coro because we want to cede,
532	# to reduce pressure on the coro pool (because most callbacks	628	# to reduce pressure on the coro pool (because most callbacks
533	# return immediately and can be reused) and because we cannot cede	629	# return immediately and can be reused) and because we cannot cede
534	# inside an event callback.	630	# inside an event callback.
535	our $unblock_scheduler = async {	631	our $unblock_scheduler = new Coro sub {
536	$current->desc ("[unblock_sub scheduler]");
537	while () {	632	while () {
538	while (my $cb = pop @unblock_queue) {	633	while (my $cb = pop @unblock_queue) {
539	# this is an inlined copy of async_pool	634	# this is an inlined copy of async_pool
540	my $coro = (pop @pool or new Coro \&pool_handler);	635	my $coro = (pop @async_pool) \|\| new Coro \&pool_handler;
541		636
542	$coro->{_invoke} = $cb;	637	$coro->{_invoke} = $cb;
543	$coro->ready;	638	$coro->ready;
544	cede; # for short-lived callbacks, this reduces pressure on the coro pool	639	cede; # for short-lived callbacks, this reduces pressure on the coro pool
545	}	640	}
546	schedule; # sleep well	641	schedule; # sleep well
547	}	642	}
548	};	643	};
		644	$unblock_scheduler->desc ("[unblock_sub scheduler]");
549		645
550	sub unblock_sub(&) {	646	sub unblock_sub(&) {
551	my $cb = shift;	647	my $cb = shift;
552		648
553	sub {	649	sub {
…		…
562		658
563	1;	659	1;
564		660
565	=head1 BUGS/LIMITATIONS	661	=head1 BUGS/LIMITATIONS
566		662
567	- you must make very sure that no coro is still active on global
568	destruction. very bad things might happen otherwise (usually segfaults).
569
570	- this module is not thread-safe. You should only ever use this module	663	This module is not perl-pseudo-thread-safe. You should only ever use this
571	from the same thread (this requirement might be loosened in the future	664	module from the same thread (this requirement might be removed in the
572	to allow per-thread schedulers, but Coro::State does not yet allow	665	future to allow per-thread schedulers, but Coro::State does not yet allow
573	this).	666	this). I recommend disabling thread support and using processes, as this
		667	is much faster and uses less memory.
574		668
575	=head1 SEE ALSO	669	=head1 SEE ALSO
576		670
		671	Event-Loop integration: L<Coro::AnyEvent>, L<Coro::EV>, L<Coro::Event>.
		672
		673	Debugging: L<Coro::Debug>.
		674
577	Support/Utility: L<Coro::Cont>, L<Coro::Specific>, L<Coro::State>, L<Coro::Util>.	675	Support/Utility: L<Coro::Specific>, L<Coro::Util>.
578		676
579	Locking/IPC: L<Coro::Signal>, L<Coro::Channel>, L<Coro::Semaphore>, L<Coro::SemaphoreSet>, L<Coro::RWLock>.	677	Locking/IPC: L<Coro::Signal>, L<Coro::Channel>, L<Coro::Semaphore>, L<Coro::SemaphoreSet>, L<Coro::RWLock>.
580		678
581	Event/IO: L<Coro::Timer>, L<Coro::Event>, L<Coro::Handle>, L<Coro::Socket>, L<Coro::Select>.	679	IO/Timers: L<Coro::Timer>, L<Coro::Handle>, L<Coro::Socket>, L<Coro::AIO>.
582		680
583	Embedding: L<Coro:MakeMaker>	681	Compatibility: L<Coro::LWP>, L<Coro::BDB>, L<Coro::Storable>, L<Coro::Select>.
		682
		683	XS API: L<Coro::MakeMaker>.
		684
		685	Low level Configuration, Coroutine Environment: L<Coro::State>.
584		686
585	=head1 AUTHOR	687	=head1 AUTHOR
586		688
587	Marc Lehmann <schmorp@schmorp.de>	689	Marc Lehmann <schmorp@schmorp.de>
588	http://home.schmorp.de/	690	http://home.schmorp.de/

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Comparing Coro/Coro.pm (file contents): Revision 1.129 by root, Wed Sep 19 22:33:08 2007 UTC vs. Revision 1.191 by root, Sat May 31 12:10:55 2008 UTC

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Comparing Coro/Coro.pm (file contents):
Revision 1.129 by root, Wed Sep 19 22:33:08 2007 UTC vs.
Revision 1.191 by root, Sat May 31 12:10:55 2008 UTC