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

Comparing Coro/Coro.pm (file contents):
Revision 1.132 by root, Thu Sep 20 22:53:23 2007 UTC vs.
Revision 1.194 by root, Tue Jul 8 20:08:40 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 $VERSION = 4.744;
56		72
57	our @EXPORT = qw(async async_pool cede schedule terminate current unblock_sub);	73	our @EXPORT = qw(async async_pool cede schedule terminate current unblock_sub);
58	our %EXPORT_TAGS = (	74	our %EXPORT_TAGS = (
59	prio => [qw(PRIO_MAX PRIO_HIGH PRIO_NORMAL PRIO_LOW PRIO_IDLE PRIO_MIN)],	75	prio => [qw(PRIO_MAX PRIO_HIGH PRIO_NORMAL PRIO_LOW PRIO_IDLE PRIO_MIN)],
60	);	76	);
61	our @EXPORT_OK = (@{$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
117		103
118	$main->{desc} = "[main::]";	104	$main->{desc} = "[main::]";
119		105
120	# maybe some other module used Coro::Specific before...	106	# maybe some other module used Coro::Specific before...
121	$main->{specific} = $current->{specific}	107	$main->{_specific} = $current->{_specific}
122	if $current;	108	if $current;
123		109
124	_set_current $main;	110	_set_current $main;
125		111
126	sub current() { $current }	112	sub current() { $current } # [DEPRECATED]
127		113
128	=item $idle	114	=item $Coro::idle
129		115
130	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
131	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
132	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.
133		124
134	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
135	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
136	coroutine so the scheduler can run it.	127	coroutine so the scheduler can run it.
137		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
138	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
139	handlers), then it must be prepared to be called recursively.	138	handlers), then it must be prepared to be called recursively itself.
140		139
141	=cut	140	=cut
142		141
143	$idle = sub {	142	$idle = sub {
144	require Carp;	143	require Carp;
…		…
151	# free coroutine data and mark as destructed	150	# free coroutine data and mark as destructed
152	$self->_destroy	151	$self->_destroy
153	or return;	152	or return;
154		153
155	# call all destruction callbacks	154	# call all destruction callbacks
156	$_->(@{$self->{status}})	155	$_->(@{$self->{_status}})
157	for @{(delete $self->{destroy_cb}) \|\| []};	156	for @{(delete $self->{_on_destroy}) \|\| []};
158	}	157	}
159		158
160	# this coroutine is necessary because a coroutine	159	# this coroutine is necessary because a coroutine
161	# cannot destroy itself.	160	# cannot destroy itself.
162	my @destroy;	161	my @destroy;
…		…
171	}	170	}
172	};	171	};
173	$manager->desc ("[coro manager]");	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;
235	our $MAX_POOL_RSS = 64 * 1024;	255	our $POOL_RSS = 16 * 1024;
236	our @pool;	256	our @async_pool;
237		257
238	sub pool_handler {	258	sub pool_handler {
		259	my $cb;
		260
239	while () {	261	while () {
240	$current->{desc} = "[async_pool]";
241
242	eval {	262	eval {
243	my ($cb, @arg) = @{ delete $current->{_invoke} or return };	263	while () {
244	$cb->(@arg);	264	_pool_1 $cb;
		265	&$cb;
		266	_pool_2 $cb;
		267	&schedule;
		268	}
245	};	269	};
		270
		271	if ($@) {
		272	last if $@ eq "\3async_pool terminate\2\n";
246	warn $@ if $@;	273	warn $@;
247		274	}
248	last if @pool >= $POOL_SIZE \|\| $current->rss >= $MAX_POOL_RSS;
249
250	push @pool, $current;
251	$current->{desc} = "[async_pool idle]";
252	$current->save (Coro::State::SAVE_DEF);
253	$current->prio (0);
254	schedule;
255	}	275	}
256	}	276	}
257		277
258	sub async_pool(&@) {	278	sub async_pool(&@) {
259	# this is also inlined into the unlock_scheduler	279	# this is also inlined into the unlock_scheduler
260	my $coro = (pop @pool) \|\| new Coro \&pool_handler;;	280	my $coro = (pop @async_pool) \|\| new Coro \&pool_handler;
261		281
262	$coro->{_invoke} = [@_];	282	$coro->{_invoke} = [@_];
263	$coro->ready;	283	$coro->ready;
264		284
265	$coro	285	$coro
266	}	286	}
267		287
		288	=back
		289
		290	=head2 STATIC METHODS
		291
		292	Static methods are actually functions that operate on the current coroutine.
		293
		294	=over 4
		295
268	=item schedule	296	=item schedule
269		297
270	Calls the scheduler. Please note that the current coroutine will not be put	298	Calls the scheduler. The scheduler will find the next coroutine that is
		299	to be run from the ready queue and switches to it. The next coroutine
		300	to be run is simply the one with the highest priority that is longest
		301	in its ready queue. If there is no coroutine ready, it will clal the
		302	C<$Coro::idle> hook.
		303
		304	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	305	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	306	again unless something else (e.g. an event handler) calls C<< ->ready >>,
273	ready.	307	thus waking you up.
		308
		309	This makes C<schedule> I<the> generic method to use to block the current
		310	coroutine and wait for events: first you remember the current coroutine in
		311	a variable, then arrange for some callback of yours to call C<< ->ready
		312	>> on that once some event happens, and last you call C<schedule> to put
		313	yourself to sleep. Note that a lot of things can wake your coroutine up,
		314	so you need to check wether the event indeed happened, e.g. by storing the
		315	status in a variable.
274		316
275	The canonical way to wait on external events is this:	317	The canonical way to wait on external events is this:
276		318
277	{	319	{
278	# remember current coroutine	320	# remember current coroutine
…		…
291	Coro::schedule while $current;	333	Coro::schedule while $current;
292	}	334	}
293		335
294	=item cede	336	=item cede
295		337
296	"Cede" to other coroutines. This function puts the current coroutine into the	338	"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	339	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.	340	up the current "timeslice" to other coroutines of the same or higher
		341	priority. Once your coroutine gets its turn again it will automatically be
		342	resumed.
299		343
300	Returns true if at least one coroutine switch has happened.	344	This function is often called C<yield> in other languages.
301		345
302	=item Coro::cede_notself	346	=item Coro::cede_notself
303		347
304	Works like cede, but is not exported by default and will cede to any	348	Works like cede, but is not exported by default and will cede to I<any>
305	coroutine, regardless of priority, once.	349	coroutine, regardless of priority. This is useful sometimes to ensure
306		350	progress is made.
307	Returns true if at least one coroutine switch has happened.
308		351
309	=item terminate [arg...]	352	=item terminate [arg...]
310		353
311	Terminates the current coroutine with the given status values (see L<cancel>).	354	Terminates the current coroutine with the given status values (see L<cancel>).
		355
		356	=item killall
		357
		358	Kills/terminates/cancels all coroutines except the currently running
		359	one. This is useful after a fork, either in the child or the parent, as
		360	usually only one of them should inherit the running coroutines.
		361
		362	Note that while this will try to free some of the main programs resources,
		363	you cnanot free all of them, so if a coroutine that is not the main
		364	program calls this function, there will be some one-time resource leak.
312		365
313	=cut	366	=cut
314		367
315	sub terminate {	368	sub terminate {
316	$current->cancel (@_);	369	$current->cancel (@_);
317	}	370	}
318		371
		372	sub killall {
		373	for (Coro::State::list) {
		374	$_->cancel
		375	if $_ != $current && UNIVERSAL::isa $_, "Coro";
		376	}
		377	}
		378
319	=back	379	=back
320		380
321	# dynamic methods
322
323	=head2 COROUTINE METHODS	381	=head2 COROUTINE METHODS
324		382
325	These are the methods you can call on coroutine objects.	383	These are the methods you can call on coroutine objects (or to create
		384	them).
326		385
327	=over 4	386	=over 4
328		387
329	=item new Coro \&sub [, @args...]	388	=item new Coro \&sub [, @args...]
330		389
331	Create a new coroutine and return it. When the sub returns the coroutine	390	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	391	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	392	called. To make the coroutine run you must first put it into the ready
334	by calling the ready method.	393	queue by calling the ready method.
335		394
336	See C<async> for additional discussion.	395	See C<async> and C<Coro::State::new> for additional info about the
		396	coroutine environment.
337		397
338	=cut	398	=cut
339		399
340	sub _run_coro {	400	sub _run_coro {
341	terminate &{+shift};	401	terminate &{+shift};
…		…
347	$class->SUPER::new (\&_run_coro, @_)	407	$class->SUPER::new (\&_run_coro, @_)
348	}	408	}
349		409
350	=item $success = $coroutine->ready	410	=item $success = $coroutine->ready
351		411
352	Put the given coroutine into the ready queue (according to it's priority)	412	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	413	queue for each priority) and return true. If the coroutine is already in
354	and return false.	414	the ready queue, do nothing and return false.
		415
		416	This ensures that the scheduler will resume this coroutine automatically
		417	once all the coroutines of higher priority and all coroutines of the same
		418	priority that were put into the ready queue earlier have been resumed.
355		419
356	=item $is_ready = $coroutine->is_ready	420	=item $is_ready = $coroutine->is_ready
357		421
358	Return wether the coroutine is currently the ready queue or not,	422	Return wether the coroutine is currently the ready queue or not,
359		423
…		…
365		429
366	=cut	430	=cut
367		431
368	sub cancel {	432	sub cancel {
369	my $self = shift;	433	my $self = shift;
370	$self->{status} = [@_];	434	$self->{_status} = [@_];
371		435
372	if ($current == $self) {	436	if ($current == $self) {
373	push @destroy, $self;	437	push @destroy, $self;
374	$manager->ready;	438	$manager->ready;
375	&schedule while 1;	439	&schedule while 1;
…		…
379	}	443	}
380		444
381	=item $coroutine->join	445	=item $coroutine->join
382		446
383	Wait until the coroutine terminates and return any values given to the	447	Wait until the coroutine terminates and return any values given to the
384	C<terminate> or C<cancel> functions. C<join> can be called multiple times	448	C<terminate> or C<cancel> functions. C<join> can be called concurrently
385	from multiple coroutine.	449	from multiple coroutines, and all will be resumed and given the status
		450	return once the C<$coroutine> terminates.
386		451
387	=cut	452	=cut
388		453
389	sub join {	454	sub join {
390	my $self = shift;	455	my $self = shift;
391		456
392	unless ($self->{status}) {	457	unless ($self->{_status}) {
393	my $current = $current;	458	my $current = $current;
394		459
395	push @{$self->{destroy_cb}}, sub {	460	push @{$self->{_on_destroy}}, sub {
396	$current->ready;	461	$current->ready;
397	undef $current;	462	undef $current;
398	};	463	};
399		464
400	&schedule while $current;	465	&schedule while $current;
401	}	466	}
402		467
403	wantarray ? @{$self->{status}} : $self->{status}[0];	468	wantarray ? @{$self->{_status}} : $self->{_status}[0];
404	}	469	}
405		470
406	=item $coroutine->on_destroy (\&cb)	471	=item $coroutine->on_destroy (\&cb)
407		472
408	Registers a callback that is called when this coroutine gets destroyed,	473	Registers a callback that is called when this coroutine gets destroyed,
409	but before it is joined. The callback gets passed the terminate arguments,	474	but before it is joined. The callback gets passed the terminate arguments,
410	if any.	475	if any, and I<must not> die, under any circumstances.
411		476
412	=cut	477	=cut
413		478
414	sub on_destroy {	479	sub on_destroy {
415	my ($self, $cb) = @_;	480	my ($self, $cb) = @_;
416		481
417	push @{ $self->{destroy_cb} }, $cb;	482	push @{ $self->{_on_destroy} }, $cb;
418	}	483	}
419		484
420	=item $oldprio = $coroutine->prio ($newprio)	485	=item $oldprio = $coroutine->prio ($newprio)
421		486
422	Sets (or gets, if the argument is missing) the priority of the	487	Sets (or gets, if the argument is missing) the priority of the
…		…
447	=item $olddesc = $coroutine->desc ($newdesc)	512	=item $olddesc = $coroutine->desc ($newdesc)
448		513
449	Sets (or gets in case the argument is missing) the description for this	514	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.	515	coroutine. This is just a free-form string you can associate with a coroutine.
451		516
		517	This method simply sets the C<< $coroutine->{desc} >> member to the given string. You
		518	can modify this member directly if you wish.
		519
		520	=item $coroutine->throw ([$scalar])
		521
		522	If C<$throw> is specified and defined, it will be thrown as an exception
		523	inside the coroutine at the next convinient point in time (usually after
		524	it gains control at the next schedule/transfer/cede). Otherwise clears the
		525	exception object.
		526
		527	The exception object will be thrown "as is" with the specified scalar in
		528	C<$@>, i.e. if it is a string, no line number or newline will be appended
		529	(unlike with C<die>).
		530
		531	This can be used as a softer means than C<cancel> to ask a coroutine to
		532	end itself, although there is no guarentee that the exception will lead to
		533	termination, and if the exception isn't caught it might well end the whole
		534	program.
		535
452	=cut	536	=cut
453		537
454	sub desc {	538	sub desc {
455	my $old = $_[0]{desc};	539	my $old = $_[0]{desc};
456	$_[0]{desc} = $_[1] if @_ > 1;	540	$_[0]{desc} = $_[1] if @_ > 1;
…		…
464	=over 4	548	=over 4
465		549
466	=item Coro::nready	550	=item Coro::nready
467		551
468	Returns the number of coroutines that are currently in the ready state,	552	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	553	i.e. that can be switched to by calling C<schedule> directory or
		554	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,	555	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	556	would cause a deadlock unless there is an idle handler that wakes up some
472	that wakes up some coroutines.	557	coroutines.
473		558
474	=item my $guard = Coro::guard { ... }	559	=item my $guard = Coro::guard { ... }
475		560
476	This creates and returns a guard object. Nothing happens until the object	561	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	562	gets destroyed, in which case the codeblock given as argument will be
…		…
506		591
507		592
508	=item unblock_sub { ... }	593	=item unblock_sub { ... }
509		594
510	This utility function takes a BLOCK or code reference and "unblocks" it,	595	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	596	returning a new coderef. Unblocking means that calling the new coderef
512	immediately without blocking, returning nothing, while the original code	597	will return immediately without blocking, returning nothing, while the
513	ref will be called (with parameters) from within its own coroutine.	598	original code ref will be called (with parameters) from within another
		599	coroutine.
514		600
515	The reason this function exists is that many event libraries (such as the	601	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	602	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,	603	of thread-safety). This means you must not block within event callbacks,
518	otherwise you might suffer from crashes or worse.	604	otherwise you might suffer from crashes or worse. The only event library
		605	currently known that is safe to use without C<unblock_sub> is L<EV>.
519		606
520	This function allows your callbacks to block by executing them in another	607	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	608	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	609	is when you use the L<Coro::AIO\|Coro::AIO> functions to save results to
523	disk.	610	disk, for example.
524		611
525	In short: simply use C<unblock_sub { ... }> instead of C<sub { ... }> when	612	In short: simply use C<unblock_sub { ... }> instead of C<sub { ... }> when
526	creating event callbacks that want to block.	613	creating event callbacks that want to block.
		614
		615	If your handler does not plan to block (e.g. simply sends a message to
		616	another coroutine, or puts some other coroutine into the ready queue),
		617	there is no reason to use C<unblock_sub>.
		618
		619	Note that you also need to use C<unblock_sub> for any other callbacks that
		620	are indirectly executed by any C-based event loop. For example, when you
		621	use a module that uses L<AnyEvent> (and you use L<Coro::AnyEvent>) and it
		622	provides callbacks that are the result of some event callback, then you
		623	must not block either, or use C<unblock_sub>.
527		624
528	=cut	625	=cut
529		626
530	our @unblock_queue;	627	our @unblock_queue;
531		628
…		…
535	# inside an event callback.	632	# inside an event callback.
536	our $unblock_scheduler = new Coro sub {	633	our $unblock_scheduler = new Coro sub {
537	while () {	634	while () {
538	while (my $cb = pop @unblock_queue) {	635	while (my $cb = pop @unblock_queue) {
539	# this is an inlined copy of async_pool	636	# this is an inlined copy of async_pool
540	my $coro = (pop @pool or new Coro \&pool_handler);	637	my $coro = (pop @async_pool) \|\| new Coro \&pool_handler;
541		638
542	$coro->{_invoke} = $cb;	639	$coro->{_invoke} = $cb;
543	$coro->ready;	640	$coro->ready;
544	cede; # for short-lived callbacks, this reduces pressure on the coro pool	641	cede; # for short-lived callbacks, this reduces pressure on the coro pool
545	}	642	}
…		…
563		660
564	1;	661	1;
565		662
566	=head1 BUGS/LIMITATIONS	663	=head1 BUGS/LIMITATIONS
567		664
568	- you must make very sure that no coro is still active on global
569	destruction. very bad things might happen otherwise (usually segfaults).
570
571	- this module is not thread-safe. You should only ever use this module	665	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	666	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	667	future to allow per-thread schedulers, but Coro::State does not yet allow
574	this).	668	this). I recommend disabling thread support and using processes, as this
		669	is much faster and uses less memory.
575		670
576	=head1 SEE ALSO	671	=head1 SEE ALSO
577		672
		673	Event-Loop integration: L<Coro::AnyEvent>, L<Coro::EV>, L<Coro::Event>.
		674
		675	Debugging: L<Coro::Debug>.
		676
578	Support/Utility: L<Coro::Cont>, L<Coro::Specific>, L<Coro::State>, L<Coro::Util>.	677	Support/Utility: L<Coro::Specific>, L<Coro::Util>.
579		678
580	Locking/IPC: L<Coro::Signal>, L<Coro::Channel>, L<Coro::Semaphore>, L<Coro::SemaphoreSet>, L<Coro::RWLock>.	679	Locking/IPC: L<Coro::Signal>, L<Coro::Channel>, L<Coro::Semaphore>, L<Coro::SemaphoreSet>, L<Coro::RWLock>.
581		680
582	Event/IO: L<Coro::Timer>, L<Coro::Event>, L<Coro::Handle>, L<Coro::Socket>, L<Coro::Select>.	681	IO/Timers: L<Coro::Timer>, L<Coro::Handle>, L<Coro::Socket>, L<Coro::AIO>.
583		682
584	Embedding: L<Coro:MakeMaker>	683	Compatibility: L<Coro::LWP>, L<Coro::BDB>, L<Coro::Storable>, L<Coro::Select>.
		684
		685	XS API: L<Coro::MakeMaker>.
		686
		687	Low level Configuration, Coroutine Environment: L<Coro::State>.
585		688
586	=head1 AUTHOR	689	=head1 AUTHOR
587		690
588	Marc Lehmann <schmorp@schmorp.de>	691	Marc Lehmann <schmorp@schmorp.de>
589	http://home.schmorp.de/	692	http://home.schmorp.de/

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Comparing Coro/Coro.pm (file contents): Revision 1.132 by root, Thu Sep 20 22:53:23 2007 UTC vs. Revision 1.194 by root, Tue Jul 8 20:08:40 2008 UTC

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Comparing Coro/Coro.pm (file contents):
Revision 1.132 by root, Thu Sep 20 22:53:23 2007 UTC vs.
Revision 1.194 by root, Tue Jul 8 20:08:40 2008 UTC