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

Comparing Coro/Coro.pm (file contents):
Revision 1.105 by root, Fri Jan 5 16:55:01 2007 UTC vs.
Revision 1.206 by root, Thu Oct 30 09:57:00 2008 UTC

…		…
2		2
3	Coro - coroutine process abstraction	3	Coro - coroutine process abstraction
4		4
5	=head1 SYNOPSIS	5	=head1 SYNOPSIS
6		6
7	use Coro;	7	use Coro;
8		8
9	async {	9	async {
10	# some asynchronous thread of execution	10	# some asynchronous thread of execution
		11	print "2\n";
		12	cede; # yield back to main
		13	print "4\n";
11	};	14	};
12		15	print "1\n";
13	# alternatively create an async coroutine like this:	16	cede; # yield to coroutine
14		17	print "3\n";
15	sub some_func : Coro {	18	cede; # and again
16	# some more async code	19
17	}	20	# use locking
18		21	use Coro::Semaphore;
19	cede;	22	my $lock = new Coro::Semaphore;
		23	my $locked;
		24
		25	$lock->down;
		26	$locked = 1;
		27	$lock->up;
20		28
21	=head1 DESCRIPTION	29	=head1 DESCRIPTION
22		30
23	This module collection manages coroutines. Coroutines are similar	31	This module collection manages coroutines. Coroutines are similar to
24	to threads but don't run in parallel at the same time even on SMP	32	threads but don't (in general) run in parallel at the same time even
25	machines. The specific flavor of coroutine use din this module also	33	on SMP machines. The specific flavor of coroutine used in this module
26	guarentees you that it will not switch between coroutines unless	34	also guarantees you that it will not switch between coroutines unless
27	necessary, at easily-identified points in your program, so locking and	35	necessary, at easily-identified points in your program, so locking and
28	parallel access are rarely an issue, making coroutine programming much	36	parallel access are rarely an issue, making coroutine programming much
29	safer than threads programming.	37	safer and easier than threads programming.
30		38
31	(Perl, however, does not natively support real threads but instead does a	39	Unlike a normal perl program, however, coroutines allow you to have
32	very slow and memory-intensive emulation of processes using threads. This	40	multiple running interpreters that share data, which is especially useful
33	is a performance win on Windows machines, and a loss everywhere else).	41	to code pseudo-parallel processes and for event-based programming, such as
		42	multiple HTTP-GET requests running concurrently. See L<Coro::AnyEvent> to
		43	learn more.
		44
		45	Coroutines are also useful because Perl has no support for threads (the so
		46	called "threads" that perl offers are nothing more than the (bad) process
		47	emulation coming from the Windows platform: On standard operating systems
		48	they serve no purpose whatsoever, except by making your programs slow and
		49	making them use a lot of memory. Best disable them when building perl, or
		50	aks your software vendor/distributor to do it for you).
34		51
35	In this module, coroutines are defined as "callchain + lexical variables +	52	In this module, coroutines are defined as "callchain + lexical variables +
36	@_ + $_ + $@ + $/ + C stack), that is, a coroutine has its own callchain,	53	@_ + $_ + $@ + $/ + C stack), that is, a coroutine has its own callchain,
37	its own set of lexicals and its own set of perls most important global	54	its own set of lexicals and its own set of perls most important global
38	variables.	55	variables (see L<Coro::State> for more configuration).
39		56
40	=cut	57	=cut
41		58
42	package Coro;	59	package Coro;
43		60
…		…
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 = '3.3';	72	our $VERSION = 4.802;
56		73
57	our @EXPORT = qw(async async_pool cede schedule terminate current unblock_sub);	74	our @EXPORT = qw(async async_pool cede schedule terminate current unblock_sub);
58	our %EXPORT_TAGS = (	75	our %EXPORT_TAGS = (
59	prio => [qw(PRIO_MAX PRIO_HIGH PRIO_NORMAL PRIO_LOW PRIO_IDLE PRIO_MIN)],	76	prio => [qw(PRIO_MAX PRIO_HIGH PRIO_NORMAL PRIO_LOW PRIO_IDLE PRIO_MIN)],
60	);	77	);
61	our @EXPORT_OK = (@{$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 = new Coro;
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<$main> (of course).
111		98
112	This variable is B<strictly> I<read-only>. It is provided for performance	99	This variable is B<strictly> I<read-only>. You can take copies of the
113	reasons. If performance is not essentiel you are encouraged to use the	100	value stored in it and use it as any other coroutine object, but you must
114	C<Coro::current> function instead.	101	not otherwise modify the variable itself.
115		102
116	=cut	103	=cut
		104
		105	$main->{desc} = "[main::]";
117		106
118	# maybe some other module used Coro::Specific before...	107	# maybe some other module used Coro::Specific before...
119	$main->{specific} = $current->{specific}	108	$main->{_specific} = $current->{_specific}
120	if $current;	109	if $current;
121		110
122	_set_current $main;	111	_set_current $main;
123		112
124	sub current() { $current }	113	sub current() { $current } # [DEPRECATED]
125		114
126	=item $idle	115	=item $Coro::idle
127		116
128	A callback that is called whenever the scheduler finds no ready coroutines	117	This variable is mainly useful to integrate Coro into event loops. It is
129	to run. The default implementation prints "FATAL: deadlock detected" and	118	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.	119	pretty low-level functionality.
		120
		121	This variable stores a callback that is called whenever the scheduler
		122	finds no ready coroutines to run. The default implementation prints
		123	"FATAL: deadlock detected" and exits, because the program has no other way
		124	to continue.
131		125
132	This hook is overwritten by modules such as C<Coro::Timer> and	126	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	127	C<Coro::AnyEvent> to wait on an external event that hopefully wake up a
134	coroutine so the scheduler can run it.	128	coroutine so the scheduler can run it.
135		129
		130	Note that the callback I<must not>, under any circumstances, block
		131	the current coroutine. Normally, this is achieved by having an "idle
		132	coroutine" that calls the event loop and then blocks again, and then
		133	readying that coroutine in the idle handler.
		134
		135	See L<Coro::Event> or L<Coro::AnyEvent> for examples of using this
		136	technique.
		137
136	Please note that if your callback recursively invokes perl (e.g. for event	138	Please note that if your callback recursively invokes perl (e.g. for event
137	handlers), then it must be prepared to be called recursively.	139	handlers), then it must be prepared to be called recursively itself.
138		140
139	=cut	141	=cut
140		142
141	$idle = sub {	143	$idle = sub {
142	require Carp;	144	require Carp;
…		…
149	# free coroutine data and mark as destructed	151	# free coroutine data and mark as destructed
150	$self->_destroy	152	$self->_destroy
151	or return;	153	or return;
152		154
153	# call all destruction callbacks	155	# call all destruction callbacks
154	$_->(@{$self->{status}})	156	$_->(@{$self->{_status}})
155	for @{(delete $self->{destroy_cb}) \|\| []};	157	for @{(delete $self->{_on_destroy}) \|\| []};
156	}	158	}
157		159
158	# this coroutine is necessary because a coroutine	160	# this coroutine is necessary because a coroutine
159	# cannot destroy itself.	161	# cannot destroy itself.
160	my @destroy;	162	my @destroy;
…		…
166	while @destroy;	168	while @destroy;
167		169
168	&schedule;	170	&schedule;
169	}	171	}
170	};	172	};
171		173	$manager->desc ("[coro manager]");
172	$manager->prio (PRIO_MAX);	174	$manager->prio (PRIO_MAX);
173		175
174	# static methods. not really.
175
176	=back	176	=back
177		177
178	=head2 STATIC METHODS	178	=head2 SIMPLE COROUTINE CREATION
179
180	Static methods are actually functions that operate on the current coroutine only.
181		179
182	=over 4	180	=over 4
183		181
184	=item async { ... } [@args...]	182	=item async { ... } [@args...]
185		183
186	Create a new asynchronous coroutine and return it's coroutine object	184	Create a new coroutine and return it's coroutine object (usually
187	(usually unused). When the sub returns the new coroutine is automatically	185	unused). The coroutine will be put into the ready queue, so
		186	it will start running automatically on the next scheduler run.
		187
		188	The first argument is a codeblock/closure that should be executed in the
		189	coroutine. When it returns argument returns the coroutine is automatically
188	terminated.	190	terminated.
189		191
190	Calling C<exit> in a coroutine will not work correctly, so do not do that.	192	The remaining arguments are passed as arguments to the closure.
191		193
192	When the coroutine dies, the program will exit, just as in the main	194	See the C<Coro::State::new> constructor for info about the coroutine
193	program.	195	environment in which coroutines are executed.
194		196
		197	Calling C<exit> in a coroutine will do the same as calling exit outside
		198	the coroutine. Likewise, when the coroutine dies, the program will exit,
		199	just as it would in the main program.
		200
		201	If you do not want that, you can provide a default C<die> handler, or
		202	simply avoid dieing (by use of C<eval>).
		203
195	# create a new coroutine that just prints its arguments	204	Example: Create a new coroutine that just prints its arguments.
		205
196	async {	206	async {
197	print "@_\n";	207	print "@_\n";
198	} 1,2,3,4;	208	} 1,2,3,4;
199		209
200	=cut	210	=cut
…		…
206	}	216	}
207		217
208	=item async_pool { ... } [@args...]	218	=item async_pool { ... } [@args...]
209		219
210	Similar to C<async>, but uses a coroutine pool, so you should not call	220	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	221	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 :).	222	coroutine that might have executed other code already (which can be good
		223	or bad :).
213		224
		225	On the plus side, this function is faster than creating (and destroying)
		226	a completly new coroutine, so if you need a lot of generic coroutines in
		227	quick successsion, use C<async_pool>, not C<async>.
		228
214	Also, the block is executed in an C<eval> context and a warning will be	229	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 C<async> does.	230	issued in case of an exception instead of terminating the program, as
		231	C<async> does. As the coroutine is being reused, stuff like C<on_destroy>
		232	will not work in the expected way, unless you call terminate or cancel,
		233	which somehow defeats the purpose of pooling (but is fine in the
		234	exceptional case).
216		235
217	The priority will be reset to C<0> after each job, otherwise the coroutine	236	The priority will be reset to C<0> after each run, tracing will be
218	will be re-used "as-is".	237	disabled, the description will be reset and the default output filehandle
		238	gets restored, so you can change all these. Otherwise the coroutine will
		239	be re-used "as-is": most notably if you change other per-coroutine global
		240	stuff such as C<$/> you I<must needs> revert that change, which is most
		241	simply done by using local as in: C<< local $/ >>.
219		242
220	The pool size is limited to 8 idle coroutines (this can be adjusted by	243	The idle pool size is limited to C<8> idle coroutines (this can be
221	changing $Coro::POOL_SIZE), and there can be as many non-idle coros as	244	adjusted by changing $Coro::POOL_SIZE), but there can be as many non-idle
222	required.	245	coros as required.
223		246
224	If you are concerned about pooled coroutines growing a lot because a	247	If you are concerned about pooled coroutines growing a lot because a
225	single C<async_pool> used a lot of stackspace you can e.g. C<async_pool {	248	single C<async_pool> used a lot of stackspace you can e.g. C<async_pool
226	terminate }> once per second or so to slowly replenish the pool.	249	{ terminate }> once per second or so to slowly replenish the pool. In
		250	addition to that, when the stacks used by a handler grows larger than 16kb
		251	(adjustable via $Coro::POOL_RSS) it will also be destroyed.
227		252
228	=cut	253	=cut
229		254
230	our $POOL_SIZE = 8;	255	our $POOL_SIZE = 8;
		256	our $POOL_RSS = 16 * 1024;
231	our @pool;	257	our @async_pool;
232		258
233	sub pool_handler {	259	sub pool_handler {
		260	my $cb;
		261
234	while () {	262	while () {
235	my ($cb, @arg) = @{ delete $current->{_invoke} };
236
237	eval {	263	eval {
238	$cb->(@arg);	264	while () {
		265	_pool_1 $cb;
		266	&$cb;
		267	_pool_2 $cb;
		268	&schedule;
		269	}
239	};	270	};
		271
		272	if ($@) {
		273	last if $@ eq "\3async_pool terminate\2\n";
240	warn $@ if $@;	274	warn $@;
241		275	}
242	last if @pool >= $POOL_SIZE;	276	}
243	push @pool, $current;	277	}
244
245	$current->prio (0);
246	schedule;
247	}
248	}
249		278
250	sub async_pool(&@) {	279	sub async_pool(&@) {
251	# this is also inlined into the unlock_scheduler	280	# this is also inlined into the unlock_scheduler
252	my $coro = (pop @pool or new Coro \&pool_handler);	281	my $coro = (pop @async_pool) \|\| new Coro \&pool_handler;
253		282
254	$coro->{_invoke} = [@_];	283	$coro->{_invoke} = [@_];
255	$coro->ready;	284	$coro->ready;
256		285
257	$coro	286	$coro
258	}	287	}
259		288
		289	=back
		290
		291	=head2 STATIC METHODS
		292
		293	Static methods are actually functions that operate on the current coroutine.
		294
		295	=over 4
		296
260	=item schedule	297	=item schedule
261		298
262	Calls the scheduler. Please note that the current coroutine will not be put	299	Calls the scheduler. The scheduler will find the next coroutine that is
		300	to be run from the ready queue and switches to it. The next coroutine
		301	to be run is simply the one with the highest priority that is longest
		302	in its ready queue. If there is no coroutine ready, it will clal the
		303	C<$Coro::idle> hook.
		304
		305	Please note that the current coroutine will I<not> be put into the ready
263	into the ready queue, so calling this function usually means you will	306	queue, so calling this function usually means you will never be called
264	never be called again unless something else (e.g. an event handler) calls	307	again unless something else (e.g. an event handler) calls C<< ->ready >>,
265	ready.	308	thus waking you up.
		309
		310	This makes C<schedule> I<the> generic method to use to block the current
		311	coroutine and wait for events: first you remember the current coroutine in
		312	a variable, then arrange for some callback of yours to call C<< ->ready
		313	>> on that once some event happens, and last you call C<schedule> to put
		314	yourself to sleep. Note that a lot of things can wake your coroutine up,
		315	so you need to check whether the event indeed happened, e.g. by storing the
		316	status in a variable.
266		317
267	The canonical way to wait on external events is this:	318	The canonical way to wait on external events is this:
268		319
269	{	320	{
270	# remember current coroutine	321	# remember current coroutine
…		…
275	# wake up sleeping coroutine	326	# wake up sleeping coroutine
276	$current->ready;	327	$current->ready;
277	undef $current;	328	undef $current;
278	};	329	};
279		330
280	# call schedule until event occured.	331	# call schedule until event occurred.
281	# in case we are woken up for other reasons	332	# in case we are woken up for other reasons
282	# (current still defined), loop.	333	# (current still defined), loop.
283	Coro::schedule while $current;	334	Coro::schedule while $current;
284	}	335	}
285		336
286	=item cede	337	=item cede
287		338
288	"Cede" to other coroutines. This function puts the current coroutine into the	339	"Cede" to other coroutines. This function puts the current coroutine into
289	ready queue and calls C<schedule>, which has the effect of giving up the	340	the ready queue and calls C<schedule>, which has the effect of giving
290	current "timeslice" to other coroutines of the same or higher priority.	341	up the current "timeslice" to other coroutines of the same or higher
		342	priority. Once your coroutine gets its turn again it will automatically be
		343	resumed.
		344
		345	This function is often called C<yield> in other languages.
291		346
292	=item Coro::cede_notself	347	=item Coro::cede_notself
293		348
294	Works like cede, but is not exported by default and will cede to any	349	Works like cede, but is not exported by default and will cede to I<any>
295	coroutine, regardless of priority, once.	350	coroutine, regardless of priority. This is useful sometimes to ensure
		351	progress is made.
296		352
297	=item terminate [arg...]	353	=item terminate [arg...]
298		354
299	Terminates the current coroutine with the given status values (see L<cancel>).	355	Terminates the current coroutine with the given status values (see L<cancel>).
		356
		357	=item killall
		358
		359	Kills/terminates/cancels all coroutines except the currently running
		360	one. This is useful after a fork, either in the child or the parent, as
		361	usually only one of them should inherit the running coroutines.
		362
		363	Note that while this will try to free some of the main programs resources,
		364	you cannot free all of them, so if a coroutine that is not the main
		365	program calls this function, there will be some one-time resource leak.
300		366
301	=cut	367	=cut
302		368
303	sub terminate {	369	sub terminate {
304	$current->cancel (@_);	370	$current->cancel (@_);
305	}	371	}
306		372
		373	sub killall {
		374	for (Coro::State::list) {
		375	$_->cancel
		376	if $_ != $current && UNIVERSAL::isa $_, "Coro";
		377	}
		378	}
		379
307	=back	380	=back
308		381
309	# dynamic methods
310
311	=head2 COROUTINE METHODS	382	=head2 COROUTINE METHODS
312		383
313	These are the methods you can call on coroutine objects.	384	These are the methods you can call on coroutine objects (or to create
		385	them).
314		386
315	=over 4	387	=over 4
316		388
317	=item new Coro \&sub [, @args...]	389	=item new Coro \&sub [, @args...]
318		390
319	Create a new coroutine and return it. When the sub returns the coroutine	391	Create a new coroutine and return it. When the sub returns, the coroutine
320	automatically terminates as if C<terminate> with the returned values were	392	automatically terminates as if C<terminate> with the returned values were
321	called. To make the coroutine run you must first put it into the ready queue	393	called. To make the coroutine run you must first put it into the ready
322	by calling the ready method.	394	queue by calling the ready method.
323		395
324	Calling C<exit> in a coroutine will not work correctly, so do not do that.	396	See C<async> and C<Coro::State::new> for additional info about the
		397	coroutine environment.
325		398
326	=cut	399	=cut
327		400
328	sub _run_coro {	401	sub _run_coro {
329	terminate &{+shift};	402	terminate &{+shift};
…		…
335	$class->SUPER::new (\&_run_coro, @_)	408	$class->SUPER::new (\&_run_coro, @_)
336	}	409	}
337		410
338	=item $success = $coroutine->ready	411	=item $success = $coroutine->ready
339		412
340	Put the given coroutine into the ready queue (according to it's priority)	413	Put the given coroutine into the end of its ready queue (there is one
341	and return true. If the coroutine is already in the ready queue, do nothing	414	queue for each priority) and return true. If the coroutine is already in
342	and return false.	415	the ready queue, do nothing and return false.
		416
		417	This ensures that the scheduler will resume this coroutine automatically
		418	once all the coroutines of higher priority and all coroutines of the same
		419	priority that were put into the ready queue earlier have been resumed.
343		420
344	=item $is_ready = $coroutine->is_ready	421	=item $is_ready = $coroutine->is_ready
345		422
346	Return wether the coroutine is currently the ready queue or not,	423	Return whether the coroutine is currently the ready queue or not,
347		424
348	=item $coroutine->cancel (arg...)	425	=item $coroutine->cancel (arg...)
349		426
350	Terminates the given coroutine and makes it return the given arguments as	427	Terminates the given coroutine and makes it return the given arguments as
351	status (default: the empty list). Never returns if the coroutine is the	428	status (default: the empty list). Never returns if the coroutine is the
…		…
353		430
354	=cut	431	=cut
355		432
356	sub cancel {	433	sub cancel {
357	my $self = shift;	434	my $self = shift;
358	$self->{status} = [@_];	435	$self->{_status} = [@_];
359		436
360	if ($current == $self) {	437	if ($current == $self) {
361	push @destroy, $self;	438	push @destroy, $self;
362	$manager->ready;	439	$manager->ready;
363	&schedule while 1;	440	&schedule while 1;
…		…
367	}	444	}
368		445
369	=item $coroutine->join	446	=item $coroutine->join
370		447
371	Wait until the coroutine terminates and return any values given to the	448	Wait until the coroutine terminates and return any values given to the
372	C<terminate> or C<cancel> functions. C<join> can be called multiple times	449	C<terminate> or C<cancel> functions. C<join> can be called concurrently
373	from multiple coroutine.	450	from multiple coroutines, and all will be resumed and given the status
		451	return once the C<$coroutine> terminates.
374		452
375	=cut	453	=cut
376		454
377	sub join {	455	sub join {
378	my $self = shift;	456	my $self = shift;
379		457
380	unless ($self->{status}) {	458	unless ($self->{_status}) {
381	my $current = $current;	459	my $current = $current;
382		460
383	push @{$self->{destroy_cb}}, sub {	461	push @{$self->{_on_destroy}}, sub {
384	$current->ready;	462	$current->ready;
385	undef $current;	463	undef $current;
386	};	464	};
387		465
388	&schedule while $current;	466	&schedule while $current;
389	}	467	}
390		468
391	wantarray ? @{$self->{status}} : $self->{status}[0];	469	wantarray ? @{$self->{_status}} : $self->{_status}[0];
392	}	470	}
393		471
394	=item $coroutine->on_destroy (\&cb)	472	=item $coroutine->on_destroy (\&cb)
395		473
396	Registers a callback that is called when this coroutine gets destroyed,	474	Registers a callback that is called when this coroutine gets destroyed,
397	but before it is joined. The callback gets passed the terminate arguments,	475	but before it is joined. The callback gets passed the terminate arguments,
398	if any.	476	if any, and I<must not> die, under any circumstances.
399		477
400	=cut	478	=cut
401		479
402	sub on_destroy {	480	sub on_destroy {
403	my ($self, $cb) = @_;	481	my ($self, $cb) = @_;
404		482
405	push @{ $self->{destroy_cb} }, $cb;	483	push @{ $self->{_on_destroy} }, $cb;
406	}	484	}
407		485
408	=item $oldprio = $coroutine->prio ($newprio)	486	=item $oldprio = $coroutine->prio ($newprio)
409		487
410	Sets (or gets, if the argument is missing) the priority of the	488	Sets (or gets, if the argument is missing) the priority of the
…		…
435	=item $olddesc = $coroutine->desc ($newdesc)	513	=item $olddesc = $coroutine->desc ($newdesc)
436		514
437	Sets (or gets in case the argument is missing) the description for this	515	Sets (or gets in case the argument is missing) the description for this
438	coroutine. This is just a free-form string you can associate with a coroutine.	516	coroutine. This is just a free-form string you can associate with a coroutine.
439		517
		518	This method simply sets the C<< $coroutine->{desc} >> member to the given string. You
		519	can modify this member directly if you wish.
		520
		521	=item $coroutine->throw ([$scalar])
		522
		523	If C<$throw> is specified and defined, it will be thrown as an exception
		524	inside the coroutine at the next convinient point in time (usually after
		525	it gains control at the next schedule/transfer/cede). Otherwise clears the
		526	exception object.
		527
		528	The exception object will be thrown "as is" with the specified scalar in
		529	C<$@>, i.e. if it is a string, no line number or newline will be appended
		530	(unlike with C<die>).
		531
		532	This can be used as a softer means than C<cancel> to ask a coroutine to
		533	end itself, although there is no guarentee that the exception will lead to
		534	termination, and if the exception isn't caught it might well end the whole
		535	program.
		536
440	=cut	537	=cut
441		538
442	sub desc {	539	sub desc {
443	my $old = $_[0]{desc};	540	my $old = $_[0]{desc};
444	$_[0]{desc} = $_[1] if @_ > 1;	541	$_[0]{desc} = $_[1] if @_ > 1;
…		…
452	=over 4	549	=over 4
453		550
454	=item Coro::nready	551	=item Coro::nready
455		552
456	Returns the number of coroutines that are currently in the ready state,	553	Returns the number of coroutines that are currently in the ready state,
457	i.e. that can be swicthed to. The value C<0> means that the only runnable	554	i.e. that can be switched to by calling C<schedule> directory or
		555	indirectly. The value C<0> means that the only runnable coroutine is the
458	coroutine is the currently running one, so C<cede> would have no effect,	556	currently running one, so C<cede> would have no effect, and C<schedule>
459	and C<schedule> would cause a deadlock unless there is an idle handler	557	would cause a deadlock unless there is an idle handler that wakes up some
460	that wakes up some coroutines.	558	coroutines.
461		559
462	=item my $guard = Coro::guard { ... }	560	=item my $guard = Coro::guard { ... }
463		561
464	This creates and returns a guard object. Nothing happens until the objetc	562	This creates and returns a guard object. Nothing happens until the object
465	gets destroyed, in which case the codeblock given as argument will be	563	gets destroyed, in which case the codeblock given as argument will be
466	executed. This is useful to free locks or other resources in case of a	564	executed. This is useful to free locks or other resources in case of a
467	runtime error or when the coroutine gets canceled, as in both cases the	565	runtime error or when the coroutine gets canceled, as in both cases the
468	guard block will be executed. The guard object supports only one method,	566	guard block will be executed. The guard object supports only one method,
469	C<< ->cancel >>, which will keep the codeblock from being executed.	567	C<< ->cancel >>, which will keep the codeblock from being executed.
…		…
494		592
495		593
496	=item unblock_sub { ... }	594	=item unblock_sub { ... }
497		595
498	This utility function takes a BLOCK or code reference and "unblocks" it,	596	This utility function takes a BLOCK or code reference and "unblocks" it,
499	returning the new coderef. This means that the new coderef will return	597	returning a new coderef. Unblocking means that calling the new coderef
500	immediately without blocking, returning nothing, while the original code	598	will return immediately without blocking, returning nothing, while the
501	ref will be called (with parameters) from within its own coroutine.	599	original code ref will be called (with parameters) from within another
		600	coroutine.
502		601
503	The reason this fucntion exists is that many event libraries (such as the	602	The reason this function exists is that many event libraries (such as the
504	venerable L<Event\|Event> module) are not coroutine-safe (a weaker form	603	venerable L<Event\|Event> module) are not coroutine-safe (a weaker form
505	of thread-safety). This means you must not block within event callbacks,	604	of thread-safety). This means you must not block within event callbacks,
506	otherwise you might suffer from crashes or worse.	605	otherwise you might suffer from crashes or worse. The only event library
		606	currently known that is safe to use without C<unblock_sub> is L<EV>.
507		607
508	This function allows your callbacks to block by executing them in another	608	This function allows your callbacks to block by executing them in another
509	coroutine where it is safe to block. One example where blocking is handy	609	coroutine where it is safe to block. One example where blocking is handy
510	is when you use the L<Coro::AIO\|Coro::AIO> functions to save results to	610	is when you use the L<Coro::AIO\|Coro::AIO> functions to save results to
511	disk.	611	disk, for example.
512		612
513	In short: simply use C<unblock_sub { ... }> instead of C<sub { ... }> when	613	In short: simply use C<unblock_sub { ... }> instead of C<sub { ... }> when
514	creating event callbacks that want to block.	614	creating event callbacks that want to block.
		615
		616	If your handler does not plan to block (e.g. simply sends a message to
		617	another coroutine, or puts some other coroutine into the ready queue),
		618	there is no reason to use C<unblock_sub>.
		619
		620	Note that you also need to use C<unblock_sub> for any other callbacks that
		621	are indirectly executed by any C-based event loop. For example, when you
		622	use a module that uses L<AnyEvent> (and you use L<Coro::AnyEvent>) and it
		623	provides callbacks that are the result of some event callback, then you
		624	must not block either, or use C<unblock_sub>.
515		625
516	=cut	626	=cut
517		627
518	our @unblock_queue;	628	our @unblock_queue;
519		629
520	# we create a special coro because we want to cede,	630	# we create a special coro because we want to cede,
521	# to reduce pressure on the coro pool (because most callbacks	631	# to reduce pressure on the coro pool (because most callbacks
522	# return immediately and can be reused) and because we cannot cede	632	# return immediately and can be reused) and because we cannot cede
523	# inside an event callback.	633	# inside an event callback.
524	our $unblock_scheduler = async {	634	our $unblock_scheduler = new Coro sub {
525	while () {	635	while () {
526	while (my $cb = pop @unblock_queue) {	636	while (my $cb = pop @unblock_queue) {
527	# this is an inlined copy of async_pool	637	# this is an inlined copy of async_pool
528	my $coro = (pop @pool or new Coro \&pool_handler);	638	my $coro = (pop @async_pool) \|\| new Coro \&pool_handler;
529		639
530	$coro->{_invoke} = $cb;	640	$coro->{_invoke} = $cb;
531	$coro->ready;	641	$coro->ready;
532	cede; # for short-lived callbacks, this reduces pressure on the coro pool	642	cede; # for short-lived callbacks, this reduces pressure on the coro pool
533	}	643	}
534	schedule; # sleep well	644	schedule; # sleep well
535	}	645	}
536	};	646	};
		647	$unblock_scheduler->desc ("[unblock_sub scheduler]");
537		648
538	sub unblock_sub(&) {	649	sub unblock_sub(&) {
539	my $cb = shift;	650	my $cb = shift;
540		651
541	sub {	652	sub {
…		…
550		661
551	1;	662	1;
552		663
553	=head1 BUGS/LIMITATIONS	664	=head1 BUGS/LIMITATIONS
554		665
555	- you must make very sure that no coro is still active on global
556	destruction. very bad things might happen otherwise (usually segfaults).
557
558	- this module is not thread-safe. You should only ever use this module	666	This module is not perl-pseudo-thread-safe. You should only ever use this
559	from the same thread (this requirement might be losened in the future	667	module from the same thread (this requirement might be removed in the
560	to allow per-thread schedulers, but Coro::State does not yet allow	668	future to allow per-thread schedulers, but Coro::State does not yet allow
561	this).	669	this). I recommend disabling thread support and using processes, as this
		670	is much faster and uses less memory.
562		671
563	=head1 SEE ALSO	672	=head1 SEE ALSO
564		673
		674	Event-Loop integration: L<Coro::AnyEvent>, L<Coro::EV>, L<Coro::Event>.
		675
		676	Debugging: L<Coro::Debug>.
		677
565	Support/Utility: L<Coro::Cont>, L<Coro::Specific>, L<Coro::State>, L<Coro::Util>.	678	Support/Utility: L<Coro::Specific>, L<Coro::Util>.
566		679
567	Locking/IPC: L<Coro::Signal>, L<Coro::Channel>, L<Coro::Semaphore>, L<Coro::SemaphoreSet>, L<Coro::RWLock>.	680	Locking/IPC: L<Coro::Signal>, L<Coro::Channel>, L<Coro::Semaphore>, L<Coro::SemaphoreSet>, L<Coro::RWLock>.
568		681
569	Event/IO: L<Coro::Timer>, L<Coro::Event>, L<Coro::Handle>, L<Coro::Socket>, L<Coro::Select>.	682	IO/Timers: L<Coro::Timer>, L<Coro::Handle>, L<Coro::Socket>, L<Coro::AIO>.
570		683
571	Embedding: L<Coro:MakeMaker>	684	Compatibility: L<Coro::LWP>, L<Coro::BDB>, L<Coro::Storable>, L<Coro::Select>.
		685
		686	XS API: L<Coro::MakeMaker>.
		687
		688	Low level Configuration, Coroutine Environment: L<Coro::State>.
572		689
573	=head1 AUTHOR	690	=head1 AUTHOR
574		691
575	Marc Lehmann <schmorp@schmorp.de>	692	Marc Lehmann <schmorp@schmorp.de>
576	http://home.schmorp.de/	693	http://home.schmorp.de/

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Comparing Coro/Coro.pm (file contents): Revision 1.105 by root, Fri Jan 5 16:55:01 2007 UTC vs. Revision 1.206 by root, Thu Oct 30 09:57:00 2008 UTC

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Revision 1.105 by root, Fri Jan 5 16:55:01 2007 UTC vs.
Revision 1.206 by root, Thu Oct 30 09:57:00 2008 UTC