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

Comparing Coro/Coro.pm (file contents):
Revision 1.119 by root, Wed Mar 28 14:24:17 2007 UTC vs.
Revision 1.182 by root, Fri May 9 22:29:05 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 use din this module also	32	on SMP machines. The specific flavor of coroutine used in this module
26	guarentees 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 = '3.55';	71	our $VERSION = 4.6;
56		72
57	our @EXPORT = qw(async async_pool cede schedule terminate current unblock_sub);	73	our @EXPORT = qw(async async_pool cede schedule terminate current unblock_sub);
58	our %EXPORT_TAGS = (	74	our %EXPORT_TAGS = (
59	prio => [qw(PRIO_MAX PRIO_HIGH PRIO_NORMAL PRIO_LOW PRIO_IDLE PRIO_MIN)],	75	prio => [qw(PRIO_MAX PRIO_HIGH PRIO_NORMAL PRIO_LOW PRIO_IDLE PRIO_MIN)],
60	);	76	);
61	our @EXPORT_OK = (@{$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 essentiel 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;
…		…
166	while @destroy;	167	while @destroy;
167		168
168	&schedule;	169	&schedule;
169	}	170	}
170	};	171	};
171		172	$manager->desc ("[coro manager]");
172	$manager->prio (PRIO_MAX);	173	$manager->prio (PRIO_MAX);
173		174
174	# static methods. not really.
175
176	=back	175	=back
177		176
178	=head2 STATIC METHODS	177	=head2 SIMPLE COROUTINE CREATION
179
180	Static methods are actually functions that operate on the current coroutine only.
181		178
182	=over 4	179	=over 4
183		180
184	=item async { ... } [@args...]	181	=item async { ... } [@args...]
185		182
186	Create a new asynchronous coroutine and return it's coroutine object	183	Create a new coroutine and return it's coroutine object (usually
187	(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
188	terminated.	189	terminated.
189		190
190	Calling C<exit> in a coroutine will not work correctly, so do not do that.	191	The remaining arguments are passed as arguments to the closure.
191		192
192	When the coroutine dies, the program will exit, just as in the main	193	See the C<Coro::State::new> constructor for info about the coroutine
193	program.	194	environment in which coroutines are executed.
194		195
		196	Calling C<exit> in a coroutine will do the same as calling exit outside
		197	the coroutine. Likewise, when the coroutine dies, the program will exit,
		198	just as it would in the main program.
		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
195	# create a new coroutine that just prints its arguments	203	Example: Create a new coroutine that just prints its arguments.
		204
196	async {	205	async {
197	print "@_\n";	206	print "@_\n";
198	} 1,2,3,4;	207	} 1,2,3,4;
199		208
200	=cut	209	=cut
…		…
206	}	215	}
207		216
208	=item async_pool { ... } [@args...]	217	=item async_pool { ... } [@args...]
209		218
210	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
211	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
212	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 :).
213		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
214	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
215	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
216	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>
217	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,
218	which somehow defeats the purpose of pooling.	232	which somehow defeats the purpose of pooling (but is fine in the
		233	exceptional case).
219		234
220	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
221	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 $/ >.
222		241
223	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
224	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
225	required.	244	required.
226		245
227	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
228	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
229	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.
230		251
231	=cut	252	=cut
232		253
233	our $POOL_SIZE = 8;	254	our $POOL_SIZE = 8;
		255	our $POOL_RSS = 16 * 1024;
234	our @pool;	256	our @async_pool;
235		257
236	sub pool_handler {	258	sub pool_handler {
		259	my $cb;
		260
237	while () {	261	while () {
238	eval {	262	eval {
239	my ($cb, @arg) = @{ delete $current->{_invoke} or return };	263	while () {
240	$cb->(@arg);	264	_pool_1 $cb;
		265	&$cb;
		266	_pool_2 $cb;
		267	&schedule;
		268	}
241	};	269	};
		270
		271	last if $@ eq "\3async_pool terminate\2\n";
242	warn $@ if $@;	272	warn $@ if $@;
243
244	last if @pool >= $POOL_SIZE;
245	push @pool, $current;
246
247	$current->save (Coro::State::SAVE_DEF);
248	$current->prio (0);
249	schedule;
250	}	273	}
251	}	274	}
252		275
253	sub async_pool(&@) {	276	sub async_pool(&@) {
254	# this is also inlined into the unlock_scheduler	277	# this is also inlined into the unlock_scheduler
255	my $coro = (pop @pool or new Coro \&pool_handler);	278	my $coro = (pop @async_pool) \|\| new Coro \&pool_handler;
256		279
257	$coro->{_invoke} = [@_];	280	$coro->{_invoke} = [@_];
258	$coro->ready;	281	$coro->ready;
259		282
260	$coro	283	$coro
261	}	284	}
262		285
		286	=back
		287
		288	=head2 STATIC METHODS
		289
		290	Static methods are actually functions that operate on the current coroutine.
		291
		292	=over 4
		293
263	=item schedule	294	=item schedule
264		295
265	Calls the scheduler. Please note that the current coroutine will not be put	296	Calls the scheduler. The scheduler will find the next coroutine that is
		297	to be run from the ready queue and switches to it. The next coroutine
		298	to be run is simply the one with the highest priority that is longest
		299	in its ready queue. If there is no coroutine ready, it will clal the
		300	C<$Coro::idle> hook.
		301
		302	Please note that the current coroutine will I<not> be put into the ready
266	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
267	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 >>,
268	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.
269		314
270	The canonical way to wait on external events is this:	315	The canonical way to wait on external events is this:
271		316
272	{	317	{
273	# remember current coroutine	318	# remember current coroutine
…		…
278	# wake up sleeping coroutine	323	# wake up sleeping coroutine
279	$current->ready;	324	$current->ready;
280	undef $current;	325	undef $current;
281	};	326	};
282		327
283	# call schedule until event occured.	328	# call schedule until event occurred.
284	# in case we are woken up for other reasons	329	# in case we are woken up for other reasons
285	# (current still defined), loop.	330	# (current still defined), loop.
286	Coro::schedule while $current;	331	Coro::schedule while $current;
287	}	332	}
288		333
289	=item cede	334	=item cede
290		335
291	"Cede" to other coroutines. This function puts the current coroutine into the	336	"Cede" to other coroutines. This function puts the current coroutine into
292	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
293	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.
294		341
295	Returns true if at least one coroutine switch has happened.	342	This function is often called C<yield> in other languages.
296		343
297	=item Coro::cede_notself	344	=item Coro::cede_notself
298		345
299	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>
300	coroutine, regardless of priority, once.	347	coroutine, regardless of priority. This is useful sometimes to ensure
301		348	progress is made.
302	Returns true if at least one coroutine switch has happened.
303		349
304	=item terminate [arg...]	350	=item terminate [arg...]
305		351
306	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.
307		363
308	=cut	364	=cut
309		365
310	sub terminate {	366	sub terminate {
311	$current->cancel (@_);	367	$current->cancel (@_);
312	}	368	}
313		369
		370	sub killall {
		371	for (Coro::State::list) {
		372	$_->cancel
		373	if $_ != $current && UNIVERSAL::isa $_, "Coro";
		374	}
		375	}
		376
314	=back	377	=back
315		378
316	# dynamic methods
317
318	=head2 COROUTINE METHODS	379	=head2 COROUTINE METHODS
319		380
320	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).
321		383
322	=over 4	384	=over 4
323		385
324	=item new Coro \&sub [, @args...]	386	=item new Coro \&sub [, @args...]
325		387
326	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
327	automatically terminates as if C<terminate> with the returned values were	389	automatically terminates as if C<terminate> with the returned values were
328	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
329	by calling the ready method.	391	queue by calling the ready method.
330		392
331	Calling C<exit> in a coroutine will not work correctly, so do not do that.	393	See C<async> and C<Coro::State::new> for additional info about the
		394	coroutine environment.
332		395
333	=cut	396	=cut
334		397
335	sub _run_coro {	398	sub _run_coro {
336	terminate &{+shift};	399	terminate &{+shift};
…		…
342	$class->SUPER::new (\&_run_coro, @_)	405	$class->SUPER::new (\&_run_coro, @_)
343	}	406	}
344		407
345	=item $success = $coroutine->ready	408	=item $success = $coroutine->ready
346		409
347	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
348	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
349	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.
350		417
351	=item $is_ready = $coroutine->is_ready	418	=item $is_ready = $coroutine->is_ready
352		419
353	Return wether the coroutine is currently the ready queue or not,	420	Return wether the coroutine is currently the ready queue or not,
354		421
…		…
360		427
361	=cut	428	=cut
362		429
363	sub cancel {	430	sub cancel {
364	my $self = shift;	431	my $self = shift;
365	$self->{status} = [@_];	432	$self->{_status} = [@_];
366		433
367	if ($current == $self) {	434	if ($current == $self) {
368	push @destroy, $self;	435	push @destroy, $self;
369	$manager->ready;	436	$manager->ready;
370	&schedule while 1;	437	&schedule while 1;
…		…
374	}	441	}
375		442
376	=item $coroutine->join	443	=item $coroutine->join
377		444
378	Wait until the coroutine terminates and return any values given to the	445	Wait until the coroutine terminates and return any values given to the
379	C<terminate> or C<cancel> functions. C<join> can be called multiple times	446	C<terminate> or C<cancel> functions. C<join> can be called concurrently
380	from multiple coroutine.	447	from multiple coroutines, and all will be resumed and given the status
		448	return once the C<$coroutine> terminates.
381		449
382	=cut	450	=cut
383		451
384	sub join {	452	sub join {
385	my $self = shift;	453	my $self = shift;
386		454
387	unless ($self->{status}) {	455	unless ($self->{_status}) {
388	my $current = $current;	456	my $current = $current;
389		457
390	push @{$self->{destroy_cb}}, sub {	458	push @{$self->{_on_destroy}}, sub {
391	$current->ready;	459	$current->ready;
392	undef $current;	460	undef $current;
393	};	461	};
394		462
395	&schedule while $current;	463	&schedule while $current;
396	}	464	}
397		465
398	wantarray ? @{$self->{status}} : $self->{status}[0];	466	wantarray ? @{$self->{_status}} : $self->{_status}[0];
399	}	467	}
400		468
401	=item $coroutine->on_destroy (\&cb)	469	=item $coroutine->on_destroy (\&cb)
402		470
403	Registers a callback that is called when this coroutine gets destroyed,	471	Registers a callback that is called when this coroutine gets destroyed,
404	but before it is joined. The callback gets passed the terminate arguments,	472	but before it is joined. The callback gets passed the terminate arguments,
405	if any.	473	if any, and I<must not> die, under any circumstances.
406		474
407	=cut	475	=cut
408		476
409	sub on_destroy {	477	sub on_destroy {
410	my ($self, $cb) = @_;	478	my ($self, $cb) = @_;
411		479
412	push @{ $self->{destroy_cb} }, $cb;	480	push @{ $self->{_on_destroy} }, $cb;
413	}	481	}
414		482
415	=item $oldprio = $coroutine->prio ($newprio)	483	=item $oldprio = $coroutine->prio ($newprio)
416		484
417	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
…		…
442	=item $olddesc = $coroutine->desc ($newdesc)	510	=item $olddesc = $coroutine->desc ($newdesc)
443		511
444	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
445	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.
446		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
447	=cut	534	=cut
448		535
449	sub desc {	536	sub desc {
450	my $old = $_[0]{desc};	537	my $old = $_[0]{desc};
451	$_[0]{desc} = $_[1] if @_ > 1;	538	$_[0]{desc} = $_[1] if @_ > 1;
…		…
459	=over 4	546	=over 4
460		547
461	=item Coro::nready	548	=item Coro::nready
462		549
463	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,
464	i.e. that can be swicthed 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
465	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>
466	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
467	that wakes up some coroutines.	555	coroutines.
468		556
469	=item my $guard = Coro::guard { ... }	557	=item my $guard = Coro::guard { ... }
470		558
471	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
472	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
…		…
501		589
502		590
503	=item unblock_sub { ... }	591	=item unblock_sub { ... }
504		592
505	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,
506	returning the new coderef. This means that the new coderef will return	594	returning a new coderef. Unblocking means that calling the new coderef
507	immediately without blocking, returning nothing, while the original code	595	will return immediately without blocking, returning nothing, while the
508	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.
509		598
510	The reason this fucntion exists is that many event libraries (such as the	599	The reason this function exists is that many event libraries (such as the
511	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
512	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,
513	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>.
514		604
515	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
516	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
517	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
518	disk.	608	disk, for example.
519		609
520	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
521	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>.
522		616
523	=cut	617	=cut
524		618
525	our @unblock_queue;	619	our @unblock_queue;
526		620
527	# we create a special coro because we want to cede,	621	# we create a special coro because we want to cede,
528	# to reduce pressure on the coro pool (because most callbacks	622	# to reduce pressure on the coro pool (because most callbacks
529	# return immediately and can be reused) and because we cannot cede	623	# return immediately and can be reused) and because we cannot cede
530	# inside an event callback.	624	# inside an event callback.
531	our $unblock_scheduler = async {	625	our $unblock_scheduler = new Coro sub {
532	while () {	626	while () {
533	while (my $cb = pop @unblock_queue) {	627	while (my $cb = pop @unblock_queue) {
534	# this is an inlined copy of async_pool	628	# this is an inlined copy of async_pool
535	my $coro = (pop @pool or new Coro \&pool_handler);	629	my $coro = (pop @async_pool) \|\| new Coro \&pool_handler;
536		630
537	$coro->{_invoke} = $cb;	631	$coro->{_invoke} = $cb;
538	$coro->ready;	632	$coro->ready;
539	cede; # for short-lived callbacks, this reduces pressure on the coro pool	633	cede; # for short-lived callbacks, this reduces pressure on the coro pool
540	}	634	}
541	schedule; # sleep well	635	schedule; # sleep well
542	}	636	}
543	};	637	};
		638	$unblock_scheduler->desc ("[unblock_sub scheduler]");
544		639
545	sub unblock_sub(&) {	640	sub unblock_sub(&) {
546	my $cb = shift;	641	my $cb = shift;
547		642
548	sub {	643	sub {
…		…
557		652
558	1;	653	1;
559		654
560	=head1 BUGS/LIMITATIONS	655	=head1 BUGS/LIMITATIONS
561		656
562	- you must make very sure that no coro is still active on global
563	destruction. very bad things might happen otherwise (usually segfaults).
564
565	- this module is not thread-safe. You should only ever use this module	657	This module is not perl-pseudo-thread-safe. You should only ever use this
566	from the same thread (this requirement might be losened in the future	658	module from the same thread (this requirement might be removed in the
567	to allow per-thread schedulers, but Coro::State does not yet allow	659	future to allow per-thread schedulers, but Coro::State does not yet allow
568	this).	660	this). I recommend disabling thread support and using processes, as this
		661	is much faster and uses less memory.
569		662
570	=head1 SEE ALSO	663	=head1 SEE ALSO
571		664
		665	Event-Loop integration: L<Coro::AnyEvent>, L<Coro::EV>, L<Coro::Event>.
		666
		667	Debugging: L<Coro::Debug>.
		668
572	Support/Utility: L<Coro::Cont>, L<Coro::Specific>, L<Coro::State>, L<Coro::Util>.	669	Support/Utility: L<Coro::Specific>, L<Coro::Util>.
573		670
574	Locking/IPC: L<Coro::Signal>, L<Coro::Channel>, L<Coro::Semaphore>, L<Coro::SemaphoreSet>, L<Coro::RWLock>.	671	Locking/IPC: L<Coro::Signal>, L<Coro::Channel>, L<Coro::Semaphore>, L<Coro::SemaphoreSet>, L<Coro::RWLock>.
575		672
576	Event/IO: L<Coro::Timer>, L<Coro::Event>, L<Coro::Handle>, L<Coro::Socket>, L<Coro::Select>.	673	IO/Timers: L<Coro::Timer>, L<Coro::Handle>, L<Coro::Socket>, L<Coro::AIO>.
577		674
578	Embedding: L<Coro:MakeMaker>	675	Compatibility: L<Coro::LWP>, L<Coro::BDB>, L<Coro::Storable>, L<Coro::Select>.
		676
		677	XS API: L<Coro::MakeMaker>.
		678
		679	Low level Configuration, Coroutine Environment: L<Coro::State>.
579		680
580	=head1 AUTHOR	681	=head1 AUTHOR
581		682
582	Marc Lehmann <schmorp@schmorp.de>	683	Marc Lehmann <schmorp@schmorp.de>
583	http://home.schmorp.de/	684	http://home.schmorp.de/

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Comparing Coro/Coro.pm (file contents): Revision 1.119 by root, Wed Mar 28 14:24:17 2007 UTC vs. Revision 1.182 by root, Fri May 9 22:29:05 2008 UTC

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Comparing Coro/Coro.pm (file contents):
Revision 1.119 by root, Wed Mar 28 14:24:17 2007 UTC vs.
Revision 1.182 by root, Fri May 9 22:29:05 2008 UTC