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

Comparing cvsroot/Coro/Coro.pm (file contents):
Revision 1.140 by root, Thu Sep 27 16:25:10 2007 UTC vs.
Revision 1.222 by root, Tue Nov 18 08:59:46 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 used in this module also	33	on SMP machines. The specific flavor of coroutine used in this module
26	guarantees 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 = '3.8';	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 essential 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	$main->{desc} = "[main::]";
119
120	# maybe some other module used Coro::Specific before...
121	$main->{specific} = $current->{specific}
122	if $current;
123
124	_set_current $main;
125
126	sub current() { $current }	105	sub current() { $current } # [DEPRECATED]
127		106
128	=item $idle	107	=item $Coro::idle
129		108
130	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
131	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
132	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.
133		117
134	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
135	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
136	coroutine so the scheduler can run it.	120	coroutine so the scheduler can run it.
137		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
138	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
139	handlers), then it must be prepared to be called recursively.	131	handlers), then it must be prepared to be called recursively itself.
140		132
141	=cut	133	=cut
142		134
143	$idle = sub {	135	$idle = sub {
144	require Carp;	136	require Carp;
…		…
151	# free coroutine data and mark as destructed	143	# free coroutine data and mark as destructed
152	$self->_destroy	144	$self->_destroy
153	or return;	145	or return;
154		146
155	# call all destruction callbacks	147	# call all destruction callbacks
156	$_->(@{$self->{status}})	148	$_->(@{$self->{_status}})
157	for @{(delete $self->{destroy_cb}) \|\| []};	149	for @{ delete $self->{_on_destroy} \|\| [] };
158	}	150	}
159		151
160	# this coroutine is necessary because a coroutine	152	# this coroutine is necessary because a coroutine
161	# cannot destroy itself.	153	# cannot destroy itself.
162	my @destroy;	154	my @destroy;
…		…
168	while @destroy;	160	while @destroy;
169		161
170	&schedule;	162	&schedule;
171	}	163	}
172	};	164	};
173	$manager->desc ("[coro manager]");	165	$manager->{desc} = "[coro manager]";
174	$manager->prio (PRIO_MAX);	166	$manager->prio (PRIO_MAX);
175		167
176	# static methods. not really.
177
178	=back	168	=back
179		169
180	=head2 STATIC METHODS	170	=head2 SIMPLE COROUTINE CREATION
181
182	Static methods are actually functions that operate on the current coroutine only.
183		171
184	=over 4	172	=over 4
185		173
186	=item async { ... } [@args...]	174	=item async { ... } [@args...]
187		175
188	Create a new asynchronous coroutine and return it's coroutine object	176	Create a new coroutine and return it's coroutine object (usually
189	(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
190	terminated.	182	terminated.
		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.
191		188
192	Calling C<exit> in a coroutine will do the same as calling exit outside	189	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,	190	the coroutine. Likewise, when the coroutine dies, the program will exit,
194	just as it would in the main program.	191	just as it would in the main program.
195		192
		193	If you do not want that, you can provide a default C<die> handler, or
		194	simply avoid dieing (by use of C<eval>).
		195
196	# create a new coroutine that just prints its arguments	196	Example: Create a new coroutine that just prints its arguments.
		197
197	async {	198	async {
198	print "@_\n";	199	print "@_\n";
199	} 1,2,3,4;	200	} 1,2,3,4;
200		201
201	=cut	202	=cut
…		…
207	}	208	}
208		209
209	=item async_pool { ... } [@args...]	210	=item async_pool { ... } [@args...]
210		211
211	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
212	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
213	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 :).
214		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
215	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
216	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
217	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>
218	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,
219	which somehow defeats the purpose of pooling.	225	which somehow defeats the purpose of pooling (but is fine in the
		226	exceptional case).
220		227
221	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
222	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 $/ >>.
223		234
224	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
225	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
226	required.	237	coros as required.
227		238
228	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
229	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
230	{ terminate }> once per second or so to slowly replenish the pool. In	241	{ terminate }> once per second or so to slowly replenish the pool. In
231	addition to that, when the stacks used by a handler grows larger than 16kb	242	addition to that, when the stacks used by a handler grows larger than 16kb
232	(adjustable with $Coro::POOL_RSS) it will also exit.	243	(adjustable via $Coro::POOL_RSS) it will also be destroyed.
233		244
234	=cut	245	=cut
235		246
236	our $POOL_SIZE = 8;	247	our $POOL_SIZE = 8;
237	our $POOL_RSS = 16 * 1024;	248	our $POOL_RSS = 16 * 1024;
…		…
248	_pool_2 $cb;	259	_pool_2 $cb;
249	&schedule;	260	&schedule;
250	}	261	}
251	};	262	};
252		263
		264	if ($@) {
253	last if $@ eq "\3terminate\2\n";	265	last if $@ eq "\3async_pool terminate\2\n";
254	warn $@ if $@;	266	warn $@;
		267	}
255	}	268	}
256	}	269	}
257		270
258	sub async_pool(&@) {	271	sub async_pool(&@) {
259	# this is also inlined into the unlock_scheduler	272	# this is also inlined into the unblock_scheduler
260	my $coro = (pop @async_pool) \|\| new Coro \&pool_handler;	273	my $coro = (pop @async_pool) \|\| new Coro \&pool_handler;
261		274
262	$coro->{_invoke} = [@_];	275	$coro->{_invoke} = [@_];
263	$coro->ready;	276	$coro->ready;
264		277
265	$coro	278	$coro
266	}	279	}
267		280
		281	=back
		282
		283	=head2 STATIC METHODS
		284
		285	Static methods are actually functions that operate on the current coroutine.
		286
		287	=over 4
		288
268	=item schedule	289	=item schedule
269		290
270	Calls the scheduler. Please note that the current coroutine will not be put	291	Calls the scheduler. The scheduler will find the next coroutine that is
		292	to be run from the ready queue and switches to it. The next coroutine
		293	to be run is simply the one with the highest priority that is longest
		294	in its ready queue. If there is no coroutine ready, it will clal the
		295	C<$Coro::idle> hook.
		296
		297	Please note that the current coroutine will I<not> be put into the ready
271	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
272	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 >>,
273	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.
274		309
275	The canonical way to wait on external events is this:	310	The canonical way to wait on external events is this:
276		311
277	{	312	{
278	# remember current coroutine	313	# remember current coroutine
…		…
291	Coro::schedule while $current;	326	Coro::schedule while $current;
292	}	327	}
293		328
294	=item cede	329	=item cede
295		330
296	"Cede" to other coroutines. This function puts the current coroutine into the	331	"Cede" to other coroutines. This function puts the current coroutine into
297	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
298	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.
299		336
300	Returns true if at least one coroutine switch has happened.	337	This function is often called C<yield> in other languages.
301		338
302	=item Coro::cede_notself	339	=item Coro::cede_notself
303		340
304	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>
305	coroutine, regardless of priority, once.	342	coroutine, regardless of priority. This is useful sometimes to ensure
306		343	progress is made.
307	Returns true if at least one coroutine switch has happened.
308		344
309	=item terminate [arg...]	345	=item terminate [arg...]
310		346
311	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.
312		358
313	=cut	359	=cut
314		360
315	sub terminate {	361	sub terminate {
316	$current->cancel (@_);	362	$current->cancel (@_);
317	}	363	}
318		364
		365	sub killall {
		366	for (Coro::State::list) {
		367	$_->cancel
		368	if $_ != $current && UNIVERSAL::isa $_, "Coro";
		369	}
		370	}
		371
319	=back	372	=back
320		373
321	# dynamic methods
322
323	=head2 COROUTINE METHODS	374	=head2 COROUTINE METHODS
324		375
325	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).
326		378
327	=over 4	379	=over 4
328		380
329	=item new Coro \&sub [, @args...]	381	=item new Coro \&sub [, @args...]
330		382
331	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
332	automatically terminates as if C<terminate> with the returned values were	384	automatically terminates as if C<terminate> with the returned values were
333	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
334	by calling the ready method.	386	queue by calling the ready method.
335		387
336	See C<async> for additional discussion.	388	See C<async> and C<Coro::State::new> for additional info about the
		389	coroutine environment.
337		390
338	=cut	391	=cut
339		392
340	sub _run_coro {	393	sub _run_coro {
341	terminate &{+shift};	394	terminate &{+shift};
…		…
347	$class->SUPER::new (\&_run_coro, @_)	400	$class->SUPER::new (\&_run_coro, @_)
348	}	401	}
349		402
350	=item $success = $coroutine->ready	403	=item $success = $coroutine->ready
351		404
352	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
353	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
354	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.
355		412
356	=item $is_ready = $coroutine->is_ready	413	=item $is_ready = $coroutine->is_ready
357		414
358	Return wether the coroutine is currently the ready queue or not,	415	Return whether the coroutine is currently the ready queue or not,
359		416
360	=item $coroutine->cancel (arg...)	417	=item $coroutine->cancel (arg...)
361		418
362	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
363	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
…		…
365		422
366	=cut	423	=cut
367		424
368	sub cancel {	425	sub cancel {
369	my $self = shift;	426	my $self = shift;
370	$self->{status} = [@_];	427	$self->{_status} = [@_];
371		428
372	if ($current == $self) {	429	if ($current == $self) {
373	push @destroy, $self;	430	push @destroy, $self;
374	$manager->ready;	431	$manager->ready;
375	&schedule while 1;	432	&schedule while 1;
376	} else {	433	} else {
377	$self->_cancel;	434	$self->_cancel;
378	}	435	}
379	}	436	}
380		437
		438	=item $coroutine->throw ([$scalar])
		439
		440	If C<$throw> is specified and defined, it will be thrown as an exception
		441	inside the coroutine at the next convenient point in time. Otherwise
		442	clears the exception object.
		443
		444	Coro will check for the exception each time a schedule-like-function
		445	returns, i.e. after each C<schedule>, C<cede>, C<< Coro::Semaphore->down
		446	>>, C<< Coro::Handle->readable >> and so on. Note that this means that
		447	when a coroutine is acquiring a lock, it might only throw after it has
		448	sucessfully acquired it.
		449
		450	The exception object will be thrown "as is" with the specified scalar in
		451	C<$@>, i.e. if it is a string, no line number or newline will be appended
		452	(unlike with C<die>).
		453
		454	This can be used as a softer means than C<cancel> to ask a coroutine to
		455	end itself, although there is no guarantee that the exception will lead to
		456	termination, and if the exception isn't caught it might well end the whole
		457	program.
		458
		459	You might also think of C<throw> as being the moral equivalent of
		460	C<kill>ing a coroutine with a signal (in this case, a scalar).
		461
381	=item $coroutine->join	462	=item $coroutine->join
382		463
383	Wait until the coroutine terminates and return any values given to the	464	Wait until the coroutine terminates and return any values given to the
384	C<terminate> or C<cancel> functions. C<join> can be called multiple times	465	C<terminate> or C<cancel> functions. C<join> can be called concurrently
385	from multiple coroutine.	466	from multiple coroutines, and all will be resumed and given the status
		467	return once the C<$coroutine> terminates.
386		468
387	=cut	469	=cut
388		470
389	sub join {	471	sub join {
390	my $self = shift;	472	my $self = shift;
391		473
392	unless ($self->{status}) {	474	unless ($self->{_status}) {
393	my $current = $current;	475	my $current = $current;
394		476
395	push @{$self->{destroy_cb}}, sub {	477	push @{$self->{_on_destroy}}, sub {
396	$current->ready;	478	$current->ready;
397	undef $current;	479	undef $current;
398	};	480	};
399		481
400	&schedule while $current;	482	&schedule while $current;
401	}	483	}
402		484
403	wantarray ? @{$self->{status}} : $self->{status}[0];	485	wantarray ? @{$self->{_status}} : $self->{_status}[0];
404	}	486	}
405		487
406	=item $coroutine->on_destroy (\&cb)	488	=item $coroutine->on_destroy (\&cb)
407		489
408	Registers a callback that is called when this coroutine gets destroyed,	490	Registers a callback that is called when this coroutine gets destroyed,
409	but before it is joined. The callback gets passed the terminate arguments,	491	but before it is joined. The callback gets passed the terminate arguments,
410	if any.	492	if any, and I<must not> die, under any circumstances.
411		493
412	=cut	494	=cut
413		495
414	sub on_destroy {	496	sub on_destroy {
415	my ($self, $cb) = @_;	497	my ($self, $cb) = @_;
416		498
417	push @{ $self->{destroy_cb} }, $cb;	499	push @{ $self->{_on_destroy} }, $cb;
418	}	500	}
419		501
420	=item $oldprio = $coroutine->prio ($newprio)	502	=item $oldprio = $coroutine->prio ($newprio)
421		503
422	Sets (or gets, if the argument is missing) the priority of the	504	Sets (or gets, if the argument is missing) the priority of the
…		…
445	higher values mean lower priority, just as in unix).	527	higher values mean lower priority, just as in unix).
446		528
447	=item $olddesc = $coroutine->desc ($newdesc)	529	=item $olddesc = $coroutine->desc ($newdesc)
448		530
449	Sets (or gets in case the argument is missing) the description for this	531	Sets (or gets in case the argument is missing) the description for this
450	coroutine. This is just a free-form string you can associate with a coroutine.	532	coroutine. This is just a free-form string you can associate with a
		533	coroutine.
		534
		535	This method simply sets the C<< $coroutine->{desc} >> member to the given
		536	string. You can modify this member directly if you wish.
451		537
452	=cut	538	=cut
453		539
454	sub desc {	540	sub desc {
455	my $old = $_[0]{desc};	541	my $old = $_[0]{desc};
…		…
464	=over 4	550	=over 4
465		551
466	=item Coro::nready	552	=item Coro::nready
467		553
468	Returns the number of coroutines that are currently in the ready state,	554	Returns the number of coroutines that are currently in the ready state,
469	i.e. that can be switched to. The value C<0> means that the only runnable	555	i.e. that can be switched to by calling C<schedule> directory or
		556	indirectly. The value C<0> means that the only runnable coroutine is the
470	coroutine is the currently running one, so C<cede> would have no effect,	557	currently running one, so C<cede> would have no effect, and C<schedule>
471	and C<schedule> would cause a deadlock unless there is an idle handler	558	would cause a deadlock unless there is an idle handler that wakes up some
472	that wakes up some coroutines.	559	coroutines.
473		560
474	=item my $guard = Coro::guard { ... }	561	=item my $guard = Coro::guard { ... }
475		562
476	This creates and returns a guard object. Nothing happens until the object	563	This creates and returns a guard object. Nothing happens until the object
477	gets destroyed, in which case the codeblock given as argument will be	564	gets destroyed, in which case the codeblock given as argument will be
…		…
506		593
507		594
508	=item unblock_sub { ... }	595	=item unblock_sub { ... }
509		596
510	This utility function takes a BLOCK or code reference and "unblocks" it,	597	This utility function takes a BLOCK or code reference and "unblocks" it,
511	returning the new coderef. This means that the new coderef will return	598	returning a new coderef. Unblocking means that calling the new coderef
512	immediately without blocking, returning nothing, while the original code	599	will return immediately without blocking, returning nothing, while the
513	ref will be called (with parameters) from within its own coroutine.	600	original code ref will be called (with parameters) from within another
		601	coroutine.
514		602
515	The reason this function exists is that many event libraries (such as the	603	The reason this function exists is that many event libraries (such as the
516	venerable L<Event\|Event> module) are not coroutine-safe (a weaker form	604	venerable L<Event\|Event> module) are not coroutine-safe (a weaker form
517	of thread-safety). This means you must not block within event callbacks,	605	of thread-safety). This means you must not block within event callbacks,
518	otherwise you might suffer from crashes or worse.	606	otherwise you might suffer from crashes or worse. The only event library
		607	currently known that is safe to use without C<unblock_sub> is L<EV>.
519		608
520	This function allows your callbacks to block by executing them in another	609	This function allows your callbacks to block by executing them in another
521	coroutine where it is safe to block. One example where blocking is handy	610	coroutine where it is safe to block. One example where blocking is handy
522	is when you use the L<Coro::AIO\|Coro::AIO> functions to save results to	611	is when you use the L<Coro::AIO\|Coro::AIO> functions to save results to
523	disk.	612	disk, for example.
524		613
525	In short: simply use C<unblock_sub { ... }> instead of C<sub { ... }> when	614	In short: simply use C<unblock_sub { ... }> instead of C<sub { ... }> when
526	creating event callbacks that want to block.	615	creating event callbacks that want to block.
		616
		617	If your handler does not plan to block (e.g. simply sends a message to
		618	another coroutine, or puts some other coroutine into the ready queue),
		619	there is no reason to use C<unblock_sub>.
		620
		621	Note that you also need to use C<unblock_sub> for any other callbacks that
		622	are indirectly executed by any C-based event loop. For example, when you
		623	use a module that uses L<AnyEvent> (and you use L<Coro::AnyEvent>) and it
		624	provides callbacks that are the result of some event callback, then you
		625	must not block either, or use C<unblock_sub>.
527		626
528	=cut	627	=cut
529		628
530	our @unblock_queue;	629	our @unblock_queue;
531		630
…		…
544	cede; # for short-lived callbacks, this reduces pressure on the coro pool	643	cede; # for short-lived callbacks, this reduces pressure on the coro pool
545	}	644	}
546	schedule; # sleep well	645	schedule; # sleep well
547	}	646	}
548	};	647	};
549	$unblock_scheduler->desc ("[unblock_sub scheduler]");	648	$unblock_scheduler->{desc} = "[unblock_sub scheduler]";
550		649
551	sub unblock_sub(&) {	650	sub unblock_sub(&) {
552	my $cb = shift;	651	my $cb = shift;
553		652
554	sub {	653	sub {
…		…
563		662
564	1;	663	1;
565		664
566	=head1 BUGS/LIMITATIONS	665	=head1 BUGS/LIMITATIONS
567		666
568	- you must make very sure that no coro is still active on global	667	=over 4
569	destruction. very bad things might happen otherwise (usually segfaults).
570		668
		669	=item fork with pthread backend
		670
		671	When Coro is compiled using the pthread backend (which isn't recommended
		672	but required on many BSDs as their libcs are completely broken), then
		673	coroutines will not survive a fork. There is no known workaround except to
		674	fix your libc and use a saner backend.
		675
		676	=item perl process emulation ("threads")
		677
571	- this module is not thread-safe. You should only ever use this module	678	This module is not perl-pseudo-thread-safe. You should only ever use this
572	from the same thread (this requirement might be loosened in the future	679	module from the same thread (this requirement might be removed in the
573	to allow per-thread schedulers, but Coro::State does not yet allow	680	future to allow per-thread schedulers, but Coro::State does not yet allow
574	this).	681	this). I recommend disabling thread support and using processes, as having
		682	the windows process emulation enabled under unix roughly halves perl
		683	performance, even when not used.
		684
		685	=item coroutine switching not signal safe
		686
		687	You must not switch to another coroutine from within a signal handler
		688	(only relevant with %SIG - most event libraries provide safe signals).
		689
		690	That means you I<MUST NOT> call any function that might "block" the
		691	current coroutine - C<cede>, C<schedule> C<< Coro::Semaphore->down >> or
		692	anything that calls those. Everything else, including calling C<ready>,
		693	works.
		694
		695	=back
		696
575		697
576	=head1 SEE ALSO	698	=head1 SEE ALSO
577		699
		700	Event-Loop integration: L<Coro::AnyEvent>, L<Coro::EV>, L<Coro::Event>.
		701
		702	Debugging: L<Coro::Debug>.
		703
578	Support/Utility: L<Coro::Cont>, L<Coro::Specific>, L<Coro::State>, L<Coro::Util>.	704	Support/Utility: L<Coro::Specific>, L<Coro::Util>.
579		705
580	Locking/IPC: L<Coro::Signal>, L<Coro::Channel>, L<Coro::Semaphore>, L<Coro::SemaphoreSet>, L<Coro::RWLock>.	706	Locking/IPC: L<Coro::Signal>, L<Coro::Channel>, L<Coro::Semaphore>, L<Coro::SemaphoreSet>, L<Coro::RWLock>.
581		707
582	Event/IO: L<Coro::Timer>, L<Coro::Event>, L<Coro::Handle>, L<Coro::Socket>, L<Coro::Select>.	708	IO/Timers: L<Coro::Timer>, L<Coro::Handle>, L<Coro::Socket>, L<Coro::AIO>.
583		709
584	Embedding: L<Coro:MakeMaker>	710	Compatibility: L<Coro::LWP>, L<Coro::BDB>, L<Coro::Storable>, L<Coro::Select>.
		711
		712	XS API: L<Coro::MakeMaker>.
		713
		714	Low level Configuration, Coroutine Environment: L<Coro::State>.
585		715
586	=head1 AUTHOR	716	=head1 AUTHOR
587		717
588	Marc Lehmann <schmorp@schmorp.de>	718	Marc Lehmann <schmorp@schmorp.de>
589	http://home.schmorp.de/	719	http://home.schmorp.de/

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Revision 1.222 by root, Tue Nov 18 08:59:46 2008 UTC